JP2014166082A - Motor control device and air conditioner using the same - Google Patents

Abstract

A high-efficiency motor control device that reduces noise due to resonance between a fan and a rotor is provided.
The power source is connected to a DC power source, and the DC power of the DC power source is converted into AC power of variable voltage and variable frequency, and applied to an inverter for driving and controlling a three-phase motor and a three-phase motor for rotationally driving a load. A vector control unit that calculates voltage, a high-order component generation unit that calculates a higher-order component of the fundamental wave of the applied voltage of the vector control unit, and a high-order component generation unit that calculates the applied voltage calculated by the vector control unit A voltage adding unit for adding a second component, and a PWM pulse generating unit for controlling the pulse width of the inverter based on a signal from the voltage adding unit, with respect to a resonance sound generated by resonance of the three-phase motor and its load. The component generation unit calculates a high-order component of the order expressed by the resonance frequency of the resonance sound or the motor frequency, and the voltage addition unit adds the high-order component to the applied voltage, thereby reducing the resonance sound.
[Selection] Figure 1

Description

  The present invention relates to a control method of a motor control device and an air conditioner using the same. In particular, the present invention relates to a reduction in sound caused by a fan motor.

  Conventionally, in a small fan motor used in an air conditioner, noise generated at a specific rotation speed due to resonance between the rotor and the fan has been a problem. In order to solve the problem of noise due to resonance, the vibration is reduced by providing an anti-vibration rubber on the rotor part or an anti-vibration rubber on the fan shaft receiving part.

  One of the causes is current waveform distortion due to the difference between the induced voltage distortion of the motor and the applied voltage, and various methods have been proposed to eliminate this current waveform distortion.

  For example, Patent Document 1 discloses a technique in which a voltage that cancels torque ripple generated due to distortion of an induced voltage is created in advance as an induced voltage ripple table and added to a command voltage.

  In Patent Document 2, there is a control method for switching a modulation method according to a map of torque and rotation speed or two-dimensional coordinates of id current (d-axis) and iq current (q-axis) in order to realize high-efficiency operation. It is disclosed.

JP 2008-219966 A JP 2005-229676 A

  However, the method of providing the anti-vibration rubber for reducing the resonance noise of the fan and the rotor has a problem that the structure of the motor and the fan becomes complicated and the cost becomes high.

  Further, the inventor has confirmed through experiments that the resonance sound of the fan and the rotor does not disappear with the current sine wave technology disclosed in Patent Document 1.

  Further, the present inventor has confirmed through experiments that the method of switching the modulation method disclosed in Patent Document 2 may or may not eliminate the resonance sound of the fan and the rotor.

  Therefore, an object of the present invention is to provide a high-efficiency motor control device that reduces noise caused by resonance between a fan and a rotor.

  The motor control device of the present invention is connected to a DC power source, converts the DC power of the DC power source into AC power of variable voltage and variable frequency, and controls an inverter that drives and controls a three-phase motor, and a three-phase that drives a load to rotate. A vector control unit that calculates a voltage applied to the motor, a high-order component generation unit that calculates a high-order component of a fundamental wave of the applied voltage of the vector control unit, and a high-order component generation unit that calculates the applied voltage calculated by the vector control unit Resonance voltage generated by resonance of the three-phase motor and its load, the voltage adding unit for adding the higher-order components calculated by the above and a PWM pulse generating unit for controlling the pulse width of the inverter based on the signal of the voltage adding unit The high-order component generation unit calculates a high-order component of the order represented by the resonance frequency of the resonance sound or the motor frequency, and the voltage addition unit adds the high-order component to the applied voltage, thereby reducing the resonance sound.

  ADVANTAGE OF THE INVENTION According to this invention, the highly efficient motor control apparatus which reduced the sound by the resonance of a fan and a rotor can be provided.

It is a figure which shows the internal structure of the motor control apparatus which concerns on 1st Embodiment of this invention, and the relationship between this DC motor control apparatus, a power supply, a three-phase alternating current synchronous motor, and load. In 1st Embodiment of this invention, it is a figure which shows the method of adding the high-order component of a high-order component production | generation part to the fundamental wave of a vector control part using a rotation coordinate system in a voltage addition part. In 1st Embodiment of this invention, it is a figure which shows the method of adding the high order component of a high order component production | generation part to the fundamental wave of a vector control part using a fixed coordinate system in a voltage addition part. It is a figure which shows the characteristic of the fan noise with respect to rotation speed and a sound frequency. It is a figure which shows the noise change at the time of applying the 36th-order high order component in 130min-1. It is a figure which shows an example of the control which applies the high order component of several order with respect to rotation speed. It is a figure which shows the internal structure of the motor control apparatus which concerns on 2nd Embodiment of this invention, and the relationship between this DC motor control apparatus, a power supply, a three-phase alternating current synchronous motor, and load. In 2nd Embodiment of this invention, it is a figure which shows the method of adding the high order component of a high order component production | generation part to the fundamental wave of a vector control part using a rotation coordinate system in a current addition part. In 2nd Embodiment of this invention, it is a figure which shows the method of adding the high order component of a high order component production | generation part to the fundamental wave of a vector control part using a fixed coordinate system in a current addition part. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in general three phase modulation. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in the stationary phase 60 degree switching system which is a two-phase modulation system. It is a figure which shows the voltage waveform of the U phase in the upper stationary phase 120 degree switching system which is a two-phase modulation system, a V phase, and a W phase. It is a figure which shows the voltage waveform of U phase, V phase, and W phase in the lower stationary phase 120 degree | times switching system which is a two-phase modulation system. It is a figure which shows the internal structure of the motor control apparatus which concerns on 3rd Embodiment of this invention, and the relationship between this DC motor control apparatus, a power supply, a three-phase alternating current synchronous motor, and load. It is a figure which shows the structure of the air conditioner which concerns on 4th Embodiment of this invention.

  The motor control device of the present embodiment is connected to a DC power source, converts the DC power of the DC power source into AC power of variable voltage and variable frequency, and controls the inverter for driving the motor and the motor for rotationally driving the load. A vector control unit for calculating an applied voltage; a high-order component generation unit for calculating a higher-order component of a fundamental wave of the applied voltage of the vector control unit; and generating the higher-order component in the applied voltage calculated by the vector control unit A voltage adding unit for adding higher-order components calculated by the unit, and a PWM pulse generating unit for controlling the pulse width of the inverter based on a signal from the voltage adding unit, and generated by resonance between the motor and its load For the resonance sound, the higher-order component generation unit calculates a higher-order component of the order expressed by the ratio of the resonance frequency of the resonance sound to the motor frequency (resonance frequency frequency of the resonance sound / motor frequency). Calculated, and the voltage adding unit is added to the applied voltage the higher order components.

  Further, the motor control device of the present embodiment is connected to a DC power source, converts DC power of the DC power source into AC power of variable voltage variable frequency, and passes the inverter to the motor and the motor. A command current calculation unit that calculates current, a high-order component generation unit that calculates a high-order component of a fundamental wave of the command current that is an output of the command current calculation unit, and the high-order component generation unit calculates the command current A current adding unit for adding the higher-order components, a vector control unit for calculating a voltage to be applied to the motor from an output of the current adding unit, and pulse width controlling the inverter based on a signal from the vector control unit A PWM pulse generator, and for a resonance sound generated by resonance of the motor and its load, the higher-order component generator generates a ratio of a resonance frequency of the resonance sound to a motor frequency (of the resonance sound). Represented by excitation frequency frequency / motor frequency) calculates the higher order components of the order, the current adding unit adding the high-order component to the command current.

  In addition, the motor control device of the present embodiment is connected to a DC power source, converts the DC power of the DC power source into AC power of variable voltage variable frequency, and drives the motor to drive and rotates the load. A vector control unit that calculates a voltage applied to the motor, a high-order component generation unit that calculates a high-order component of the fundamental wave of the applied voltage of the vector control unit, and a plurality of modulation methods including a fixed two-phase modulation method. And a PWM pulse generator for controlling the pulse width of the inverter based on a signal from the voltage adder, and a high-order component corrector for correcting the high-order component corresponding to a plurality of modulation schemes. A voltage adding unit that adds the higher-order component calculated by the higher-order component correction unit to the applied voltage calculated by the control unit, and for the resonance sound generated by resonance of the motor and its load, The unit calculates a higher order component of the order represented by the ratio of the resonance frequency of the resonance sound and the motor frequency (resonance frequency frequency of the resonance sound / motor frequency), and the higher order component corrected by the higher order component is A voltage adding unit adds the applied voltage.

  Further, the motor control device of the present embodiment is connected to a DC power source, converts DC power of the DC power source into AC power of variable voltage variable frequency, and passes the inverter to the motor and the motor. A command current calculation unit that calculates current, a high-order component generation unit that calculates a high-order component of a fundamental wave of the command current that is an output of the command current calculation unit, and the high-order component corresponding to a plurality of modulation methods A high-order component correction unit that corrects the current, a current addition unit that adds the high-order component corrected by the high-order component correction unit to the command current, and an output from the current addition unit that is applied to the three-phase motor A vector control unit that calculates a voltage to be output, and a PWM pulse generation unit that has a plurality of modulation schemes including a fixed two-phase modulation scheme, and that controls the pulse width of the inverter based on a signal of the vector control unit, The motor and the motor For the resonance sound generated by the resonance of the load, the higher-order component generator calculates the higher-order component of the order expressed by the ratio of the resonance frequency of the resonance sound to the motor frequency (resonance frequency frequency of the resonance sound / motor frequency). Then, the high-order component corrected by the high-order component correction unit is added to the command current by the current adding unit according to a modulation method.

  EMBODIMENT OF THE INVENTION The form for implementing invention of this application (henceforth "embodiment") is demonstrated with reference to drawings below. A motor control device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an internal configuration of a motor control device 11 according to the first embodiment of the present invention, a motor control device 11, a DC power source 12, a three-phase AC synchronous motor (as appropriate “motor” or “three-phase motor”). It is a figure which shows the relationship between (abbreviated) 13 and load (fan) 14. FIG.

  In FIG. 1, the motor control device 11 includes an inverter 15 that is a DC-AC power converter and a control device 17 that controls the inverter 15.

  The control device 17 includes a PWM (Pulse Width Modulation) pulse generation unit 24, a vector control unit 21, a high-order component generation unit 22, and a voltage addition unit 23.

  A feature of the motor control device 11 of the first embodiment is that the control device 17 includes a high-order component generation unit 22, and when the control device 17 performs PWM control of the inverter 15, the high-order component generation unit 22 to the voltage addition unit 23. Is to add the higher order component of the voltage. By this method, noise due to resonance between the motor 13 and the fan 14 as a load is removed.

  Before describing details of the motor control device 11 of the first embodiment, which is characterized by a method for removing noise due to resonance, noise due to resonance between the motor and the fan will be described first. The motor control device 11 of one embodiment will be described in detail.

  The noise generated by the fan 3 when the fan 14 (FIG. 1) is driven by the motor 13 (FIG. 1) will be described.

  FIG. 4 is a diagram illustrating an example of characteristics of the noise of the fan 14 with respect to the rotation speed. 2 and 3 will be described later.

In FIG. 4, the horizontal axis represents the rotational speed [min ⁻¹ ], the vertical axis represents the sound frequency, and the color density represents the noise [dB]. The rotation speed [min ⁻¹ ] is the rotation speed / minute. Also, it corresponds to rpm (rotation per minute). In the following description, for example, 520 rpm / min is simply expressed as 520 min ⁻¹ . The data is obtained by changing the number of rotations every 10 min ⁻¹ . The dark portion appears in the vicinity of the sound frequencies of 280 Hz and 310 Hz, but it can be seen that the sound has a high rotation speed and a low rotation speed. Here, the rotational speed at which the sound is loud is around 780 min ⁻¹ , 520 min ⁻¹ , 390 min ⁻¹ , 270 min ⁻¹ , and 130 min ⁻¹ . This is also characterized in that the audibility deteriorates even if the absolute value of the noise at a frequency of 310 Hz is small because the total sound generated by the fan is small at low speed compared to high speed.

  If the rotation speed is 780 min-1, the motor is a three-phase AC synchronous motor. Therefore, if the number of poles of the motor is 8, the electrical frequency of the motor is 52 Hz [520 / {60 × (2/8) }]. It can be seen that the sound is generated by the excitation torque in the vicinity of 312 Hz, which is the sixth-order component, with 54 Hz as the fundamental frequency. When this concept is developed, 520, 390, 310, 260, 190, 160, 130, 110 min-1 are 9th order, 12th order, 15th order, 18th order, 24th order, 30th order, 36th order, 42nd order in order. Become. In the graph, the relationship between the frequency of each order and the fan speed is represented by a dotted line, and the point where the straight line and the resonance frequency of the sound (solid line in the graph) are within tolerance is the speed at which the resonance sound is generated. And the frequency at that time.

Therefore, in order to eliminate the resonance noise between the fan 14 and the motor (motor rotor) 13, measures against these higher-order components are taken.
(Configuration of motor controller: Part 2)
The configuration of the motor control device 11 according to the first embodiment of the present invention shown in FIG. 1 will be described again in detail.

  As described above, FIG. 1 is a diagram illustrating the configuration of the motor control device 11 according to the first embodiment of the present invention and the relationship among the DC power supply 12, the motor 13, and the fan (load) 14.

  In FIG. 1, a motor control device 11 receives DC power from a DC power supply 12 and converts it into three-phase AC power. Further, the motor (three-phase AC synchronous motor) 13 is supplied with the three-phase AC power from the motor control device 11, is driven and controlled to rotate, and rotates the fan 14.

  Next, details of the motor control device 11 will be described.

  In FIG. 1, as described above, the motor control device 11 includes the inverter 15 (power converter) that converts DC power into three-phase AC power of variable voltage and variable frequency, and the control device 17 that controls the inverter 15. It is configured. Further, a DC bus current detection circuit 16 is provided in the DC power source of the inverter 15.

  The inverter 15 includes a power conversion main circuit 51 including a diode element connected in reverse parallel to a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor), and a PWM pulse signal from a PWM pulse generation unit 24 described later. And a gate driver 52 that generates a gate signal to the IGBT (Sup, Sun, Svp, Svn, Swp, Swn) of the power conversion main circuit 51 based on 17A.

  The IGBTs (Sup, Sun) constituting the legs by connecting the IGBTs in series are connected between the DC power sources 12, and the connection points of the upper arm (Sup) and the lower arm (Sup) are U-phase AC. Output terminal.

  Similarly, IGBTs (Svp, Svn) that are connected in series to form a leg are connected between the DC power supplies 12, and the connection points of the upper arm (Svp) and the lower arm (Svn) are V-phase AC. Output terminal.

  Further, IGBTs (Swp, Swn) that are connected in series and constitute a leg are connected between the DC power supplies 12, and the connection points of the upper arm (Swp) and the lower arm (Swn) are the AC of the W phase. Output terminal.

  When the control device 17 appropriately controls the above IGBTs (Sup, Sun, Svp, Svn, Swp, Swn) via the gate driver 52, the DC power of the DC power supply 12 can be changed to a variable voltage variable frequency. Three-phase AC power is output from the U-phase, V-phase, and W-phase AC output terminals.

  The control device 17 includes a PWM pulse generation unit 24, a vector control unit 21, a high-order component generation unit 22, and a voltage addition unit 23.

  The vector control unit 21 generates a fundamental wave applied voltage command 21B to the permanent magnet synchronous motor 13 based on DC bus current information (appropriately expressed as “phase current information”) 16A detected by the DC bus current detection circuit 16. And the motor rotation speed / phase information 21A of the permanent magnet synchronous motor 13 is calculated.

  The high-order component generation unit 22 outputs the high-order component 22A of the voltage of the permanent magnet synchronous motor 13 to the voltage addition unit 23 based on the motor rotation speed / phase information 21A.

  Moreover, the voltage addition part 23 adds the high-order component 22A of a voltage to the fundamental wave applied voltage command 21B, and outputs the applied voltage command 23A.

  Further, the PWM pulse generator 24 converts the PWM voltage signal 17A into the PWM pulse signal 17A based on the applied voltage command 23A and the internal carrier signal.

  The vector control of the vector control unit 21 is, for example, ““ Study of a new vector control method for a high-speed permanent magnet synchronous motor ”, Electrotechnical D, Vol.129 (2009) No.1 pp.36-45” , "Simple vector control of a position sensorless permanent magnet synchronous motor for home appliances," Electrotechnical D, Vol.124 (2004) No.11 pp.1133-1140. is there.

  The DC bus current detection circuit 16 is connected to the negative DC bus of the DC power supply 12 and acquires phase current information in which U-phase, V-phase, and W-phase pulsating currents are mixed. The acquired phase current information is output to the vector control unit 21 as DC bus current information (phase current information) 16A.

  In addition, the method of acquiring phase current information is possible by the system etc. which are disclosed by Unexamined-Japanese-Patent No. 2004-48886, for example.

  In the first embodiment, in order to reduce noise, a high-order component is applied by the following high-order component generation unit 22 and voltage addition unit 23 of voltage.

  Hereinafter, the operations of the high-order component generation unit 22 that generates the high-order component 22A of the voltage and the voltage addition unit 23 that adds the high-order component 22A to the fundamental wave applied voltage command 21B will be described with reference to FIGS. I will explain.

  The high-order component generation unit 22 generates a high-order component based on the motor rotation speed / phase information 21A using the values of G and φ in (Equation 2) and (Equation 4) which will be described later, which are set in advance. The next component 22A is output to the voltage adder 23.

  The voltage adder 23 adds the fundamental wave applied voltage command 21B output from the vector controller 21 and the higher-order component 22A of the voltage output from the higher-order component generator 22, and outputs the result to the PWM pulse generator 24.

  As a specific configuration, there are addition in a rotating coordinate system and addition in a fixed coordinate system. Next, these methods will be described in order.

  A method of addition in the rotating coordinate system will be described with reference to FIG.

  FIG. 2 shows the first embodiment of the present invention in which the higher-order component (voltage higher-order component 22A) of the higher-order component generator 22 is transferred to the fundamental wave (fundamental wave applied voltage command 21B) of the vector controller 21. It is a figure which shows the method to add using the rotation coordinate system in the addition part.

In FIG. 2, the vector control unit 21 is a rotating coordinate system based on the magnet flux direction (d axis) of the motor rotor based on the phase current information 16 </ b> A and based on the d axis and a perpendicular direction (q axis). On the dq coordinate axis, a fundamental wave applied voltage command 21B (Vd ^* , Vq ^* ) and motor rotation speed / phase information 21A are output. Note that Vd ^* is the fundamental wave applied voltage command 21B (FIG. 1) relating to the d-axis and Vq ^* is related to the q-axis.

  The higher-order component generation unit 22 generates higher-order components 22A-d (d-axis) and 22A-q (q-axis) on the dq coordinate axis based on the motor rotation speed / phase information 21A from the vector control unit 21. Note that the high-order components 22A-d and 22A-q correspond to the high-order component 22A in FIG.

The voltage adding unit 23 adds the fundamental wave applied voltage command (Vd ^* ) and the higher-order component 22A-d on the d-axis, and outputs a d-axis applied voltage command 23A-d.

In addition, the voltage adding unit 23 adds the fundamental wave applied voltage command (Vq ^* ) and the higher-order component 22A-q on the q axis, and outputs a q-axis applied voltage command 23A-q.

  The applied voltage commands 23A-d and 23A-q are converted into U-phase, V-phase, and W-phase components by a converter (not shown), and input to the PWM pulse generator 24 (FIG. 1).

  The addition method in the fixed coordinate system will be described with reference to FIG.

  FIG. 3 shows a case where the high-order component (voltage high-order component 22A) of the high-order component generation unit 22 is transferred to the fundamental wave (fundamental wave applied voltage command 21B) of the vector control unit 21 in the first embodiment of the present invention. It is a figure which shows the method of adding using a fixed coordinate system in the addition part.

In FIG. 3, the vector control unit 21 is based on the phase current information 16A, and the three-phase AC fundamental wave applied voltage command 21B (Vu ^* , Vv ^* , Vw ^* ) in the fixed coordinate system and the motor rotation speed / phase information. 21A is output.

  The high-order component generator 22 generates high-order components 22A-U, 22A-V, and 22A-W for each phase based on the motor rotation speed / phase information 21A from the vector controller 21.

The voltage adding unit 23 outputs a three-phase alternating current fundamental wave applied voltage command 21B (Vu ^* , Vv ^* , Vw ^* ) of a fixed coordinate system and higher-order components 22A-U, 22A-V, 22A-W to each phase ( U, V, and W) are added to output applied voltage commands 23A-U, 23A-V, and 23A-W, respectively.

  Next, a method for reducing the resonance noise of the fan 14 and the rotor (rotor of the motor 13) generated at n times the motor rotation speed will be described.

  The resonance caused by the fan 14 and the rotor (13) is caused by vibration in the rotation direction, and the voltage or current of each phase of the motor is different from the coordinate axis. The resonance of the fan and the rotor is related to the component of the coordinate axis of the rotating magnetic field resulting from the synthesis of three phases having different phases every 120 degrees (2π / 3) of the motor. Therefore, it is appropriate to take measures to reduce resonance noise by converting to the dq coordinate system of the rotating coordinate system instead of the voltage of each phase of the three-phase motor (motor).

  In general, in vector control, a voltage command in the dq coordinate is given as (Equation 1).

Where, r: motor phase resistance, ω ₁ ^* : command angular velocity, L _d , L _q : d-axis and q-axis reactance, I _d ^* , I _q ^* : d-axis and q-axis command current, K _E : Induced voltage constant.

On the other hand, a high-order component is calculated as in (Equation 2) and added as shown in (Equation 3) to obtain new voltage commands V _d ^** and V _q ^** .

Where V _dn ^* , V _qn ^* : d-axis and q-axis high-order voltage components, G _n : n-order high-order component amplitude coefficient, n: high-order, θ _d : d-axis phase, φ _n : n The initial phase of the next higher order component.

The present inventor has confirmed through experiments that sound of n times the motor frequency is reduced by optimally selecting G _n and φ _n in this (Equation 2). By applying the n-th order component voltage, it is possible to suppress the torque fluctuation that is the source of the sound and reduce the sound.

  As shown in FIG. 3, a high-order component expression when a voltage is applied in a fixed coordinate system is (Expression 4).

Here, V _Un ^* , V _Vn ^* , V _Wn ^* : n-order voltage higher-order components of U, V, and W phases.

Further, (Equation 2) is expressed by the ratio G _n to the voltage amplitude and the phase difference φ _n for the voltage component. By changing G _n and φ _n , a higher-order component can be freely applied. Can do.

Next, an example of noise reduction at 130 min ⁻¹ is shown. When a high-order voltage was not applied, a noise of 35 dB was generated at 312 Hz. In FIG. 5, the horizontal axis represents the 36th-order initial phase φ ₃₆ , the vertical axis represents the noise change value, the 36th-order higher-order component amplitude coefficient G ₃₆ = 0.5%, and φ ₃₆ from −180 [deg] to 180 [deg]. deg] until they show noise variation value in the case of changing the G ₃₆ when the noise variation value and phi ₃₆ = -134 when the even changed [deg]. Thus, by setting φ ₃₆ = −134 deg and G ₃₆ = 0.4%, noise could be reduced by 19 dB.

  A method of applying the first (start) and the last (end) when applying a higher-order component will be described.

In the high-order component generation unit 22, when the rotational speed at which the high-order component is applied is reached, the amplitude value of the high-order component is gradually increased from 0 to a predetermined amplitude (soft start). For example, applying a sixth-order component (Equation 2) corresponds to gradually increasing the coefficient of G ₆ (ratio to the voltage fundamental wave amplitude).

  Further, when the rotational speed at which the high-order component is not applied is reached from the state where the high-order component is applied, the amplitude value of the high-order component is gradually reduced from a predetermined amplitude to 0 (soft end).

  By adopting the soft start and soft end when applying this higher-order component, there is no shock when the application of the higher-order component is started and finished, and stable control is achieved.

  A case where a plurality of higher-order components are combined will be described with reference to FIG. The vertical axis in FIG. 6 represents the magnitude of the amplitude coefficient of each order, and the horizontal axis represents the fan speed. If the coefficients of the amplitudes of the respective orders are implemented as shown in FIG. 6 according to the fan rotational speed, the sound can be reduced at a full rotational speed for a certain resonance sound. In the example of FIG. 6, when a certain order appears in the vicinity of a certain number of revolutions, it does not appear at any other number of revolutions. However, when there are a plurality of resonance points, the same order or a plurality of revolutions may be set.

  The present inventors have less than 5% of the proper value of the amplitude of the higher-order component based on the amplitude of the first-order component (the square root of the sum of squares of Vd and Vq). I confirmed that

  According to the first embodiment shown in FIG. 1, the resonance noise of the fan and the rotor having a frequency n times the motor frequency can be reduced by applying the n-order higher-order component with a predetermined phase and amplitude.

  A second embodiment will be described with reference to FIGS. So far, it has been explained that the sound can be reduced by applying a higher-order component of voltage, but it can also be realized by applying a higher-order component of current.

  FIG. 7 shows the internal configuration of the motor control device 11 according to the second embodiment of the present invention, the motor control device 11, the DC power source 12, and the three-phase AC synchronous motor (appropriately referred to as “motor” or “three-phase motor” as appropriate). ) 13 and a load (fan) 14.

  In FIG. 7, the configuration of the control device 18 of the motor control device 11 is characterized as the second embodiment.

  The DC power supply 12, the motor 13, the fan 14, the inverter 15, and the DC bus current detection circuit 16 are the same as those in the first embodiment shown in FIG.

  The control device 18 includes a vector control unit 21, a higher-order component generation unit 22, and a PWM pulse generation unit 24. The vector control unit 21 includes a current command generation unit 25, a current addition unit 26, and a voltage command calculation unit. It is prepared for.

  The current command generation unit 25 acquires the phase current information 16A from the DC bus current detection circuit 16, calculates the motor rotation speed / phase information 25A, and outputs it to the higher-order component generation unit 22. In addition, the command current generation unit 25 also outputs a fundamental wave current command 25B to the current addition unit 26.

  The high-order component generator 22 outputs the high-order component 22A of the current of the permanent magnet synchronous motor 13 to the current adder 26 based on the motor rotation speed / phase information 25A.

  The current adder 26 adds the higher-order component 22A of the current to the fundamental wave applied current command 25B and outputs a current command 26A.

  The voltage command calculation unit 27 calculates the voltage command 27A based on the current command 26A and outputs the voltage command 27A to the PWM pulse generation unit 24.

  Other parts having the same configuration as the first embodiment will not be described.

  In the second embodiment, in order to reduce noise, a high-order component is applied by a high-order component generation unit 22 and a current addition unit 26 described below.

  Hereinafter, the operations of the high-order component generator 22 that generates the high-order component 22A of the current and the current adder 26 that adds the high-order component 22A to the fundamental current command 25B will be described with reference to FIGS. explain.

  The high-order component generation unit 22 generates a high-order component based on the motor rotation speed / phase information 21A using the values of G and φ in (Equation 5) and (Equation 6) which are set in advance and are described later. The next component 22A is output to the voltage adder 23.

  The voltage adder 23 adds the fundamental wave applied voltage command 21B output from the vector controller 21 and the higher-order component 22A of the voltage output from the higher-order component generator 22, and outputs the result to the PWM pulse generator 24.

  As a specific configuration, there are addition in a rotating coordinate system and addition in a fixed coordinate system. Next, these methods will be described in order.

  A method of addition in the rotating coordinate system will be described with reference to FIG.

  FIG. 8 shows a second embodiment of the present invention in which a higher-order component (current higher-order component 22A) of the higher-order component generator 22 is transferred to a fundamental wave (fundamental current command 25B) of the current command generator 25. It is a figure which shows the method to add in the addition part 26 using a rotation coordinate system.

In FIG. 8, the current command generation unit 25 is based on the phase current information 16A and is based on the magnet magnetic flux direction (d-axis) of the motor rotor in a rotational coordinate system based on the d-axis and the perpendicular direction (q-axis). On a certain dq coordinate axis, a fundamental wave current command 25B (Id ^* , Iq ^* ) and motor rotation speed / phase information 25A are output. Note that Id ^* is the fundamental wave current command 25B (FIG. 7) related to the d-axis and Iq ^* is related to the q-axis.

  The high-order component generator 22 generates high-order components 22A-d (d-axis) and 22A-q (q-axis) on the dq coordinate axis based on the motor rotation speed / phase information 25A from the current command generator 25. . Note that the high-order components 22A-d and 22A-q correspond to the high-order component 22A in FIG.

The current adder 26 adds the fundamental current command (Id ^* ) and the higher-order component 22A-d on the d-axis, and outputs a d-axis current command 23A-d.

In addition, the current addition unit 23 adds the fundamental wave current command (Iq ^* ) and the higher-order component 22A-q on the q axis, and outputs a q-axis applied current command 23A-q.

  The applied current commands 23A-d and 23A-q are converted into U-phase, V-phase, and W-phase components by a converter (not shown), and input to the PWM pulse generator 24 (FIG. 7).

  Further, the addition method in the fixed coordinate system will be described with reference to FIG.

  FIG. 9 shows a case where a high-order component (current high-order component 22A) of the high-order component generator 22 is transferred to a fundamental wave (fundamental current command 25B) of the current command generator 25 in the second embodiment of the present invention. It is a figure which shows the method of adding using the fixed coordinate system in the addition part.

In FIG. 9, the current command generation unit 25 is based on the phase current information 16A, and a three-phase alternating current fundamental wave command 25B (Iu ^* , Iv ^* , Iw ^* ) in a fixed coordinate system and motor rotation speed / phase information. 25A is output.

  The high-order component generator 22 generates high-order components 22A-U, 22A-V, and 22A-W for each phase based on the motor rotation speed / phase information 25A from the current command generator 25.

The current adder 26 outputs a three-phase alternating current fundamental voltage application voltage command 25B (Iu ^* , Iv ^* , Iw ^* ) in a fixed coordinate system and higher-order components 22A-U, 22A-V, 22A-W to each phase ( U, V, and W) are added to output applied voltage commands 23A-U, 23A-V, and 23A-W, respectively.

  Next, a method for reducing the resonance noise of the fan 14 and the rotor (rotor of the motor 13) generated at n times the motor rotation speed will be described.

  The resonance caused by the fan 14 and the rotor (13) is caused by vibration in the rotation direction, and the voltage or current of each phase of the motor is different from the coordinate axis. The resonance of the fan and the rotor is related to the component of the coordinate axis of the rotating magnetic field resulting from the synthesis of three phases having different phases every 120 degrees (2π / 3) of the motor. Therefore, it is appropriate to take measures to reduce resonance noise by converting to the dq coordinate system of the rotating coordinate system instead of the voltage of each phase of the three-phase motor (motor).

  In general, in vector control, a voltage command in the dq coordinate is given as (Equation 1).

Resonance noise can be reduced by defining a higher-order component of the current by (Equation 5) and adding it to I _d ^* and I _q ^* of the dq axis in (Equation 1).

Moreover, you may add by Iu ^* , Iv ^* , Iw ^* . In this case, the high-order current is as shown in (Formula 6).

  According to the first embodiment shown in FIG. 7, the resonance noise of the fan and rotor having a frequency n times the motor frequency can be reduced by applying the n-th order higher-order component with a predetermined phase and amplitude.

  A motor control device according to a third embodiment of the present invention will be described with reference to FIGS. The third embodiment includes both the high-order component generation unit 22 and the voltage addition unit 23 of the first embodiment, and control for switching the modulation method of PWM control of a three-phase AC motor described later.

  In general, it is known to switch modulation schemes for higher efficiency, sound reduction, and electrical noise reduction.

  In addition, fixed two-phase modulation is a method in which the potential of one phase is fixed and the other two phases are modulated at a predetermined electrical angle, including a fixed phase 60 degree switching method and a fixed phase 120 degree switching method described later. Shall be referred to as

  First, the stationary phase 60 degree switching method and the stationary phase 120 degree switching method, which are control methods of the motor control device, will be described first. Then, after that, the influence of this control method on sound will be described, and control combined with high-order voltage application control will be described.

  Here, a PWM control modulation method in the motor control device will be described.

  PWM control of a general three-phase AC motor is three-phase modulation (three-phase modulation method), but when the three-phase AC motor is Y-connected, two-phase is utilized by utilizing the fact that the phase voltage and the interphase voltage are different. There is a method of performing modulation (two-phase modulation method).

  That is, by utilizing the fact that the motor current is determined not by the phase voltage but by the interphase voltage, while ensuring the interphase voltage, each phase voltage is always turned on at every predetermined period by switching on the inverter switching element. In this method, the switching loss of the inverter is reduced by sequentially fixing the electrical power level π / 3 (60 °, 60 °) to the higher power level or the lower power level.

  In this method, as described above, one phase is fixed in potential in a predetermined section, and only the other two phases are modulated (PWM control). And this phase fixed in potential is repeated in order. Therefore, since only two phases are modulated at any time, this is called two-phase modulation.

  Hereinafter, the two-phase modulation method is referred to as a fixed phase 60-degree switching method.

  Next, the voltage waveform (voltage command) of the fixed phase 60 degree switching method is shown in FIG. 11, and this method will be described.

  FIG. 11 is a diagram showing U-phase, V-phase, and W-phase voltage waveforms (voltage commands) in the fixed-phase 60-degree switching method that is a two-phase modulation method.

  FIG. 10 is a diagram showing voltage waveforms (voltage commands) of the U phase, the V phase, and the W phase in a general three-phase modulation method as a reference.

  11 and 10, the horizontal axis represents the electrical angle [°], and the vertical axis represents the ratio of the voltage to the maximum voltage at each electrical angle, that is, the duty [%].

  In FIG. 11, the W phase is constant at a lower limit voltage of 0% duty when the electrical angle is 0 degree (corresponding to [°]) to 60 degrees.

  When the W phase is 0 to 60 degrees where the duty is 0%, the voltage difference and phase between the U phase and the V phase are the same as in the case of the three-phase modulation method shown in FIG. Take a voltage waveform that maintains the same relationship. That is, from 0 degrees to 60 degrees, the W-phase has a duty of 0%, so that the U-phase and the V-phase are slightly lower than the original voltage values.

  Further, from 60 degrees to 120 degrees, the U phase is constant at the upper limit voltage with a duty of 100%. In this section, the V phase and the W phase have a voltage waveform in which the voltage difference and phase with the U phase maintain the same relationship as in the case of the three-phase modulation shown in FIG. Take a slightly higher value. Note that at 60 degrees when the U phase is 100% duty at once, the voltages of the V phase and the W phase suddenly rise.

  Also, from 120 degrees to 180 degrees, the V phase is constant at the lower limit voltage with a duty of 0%. In this section, the W phase and the U phase have a voltage waveform in which the voltage difference and phase with the V phase maintain the same relationship as in the case of the three-phase modulation method shown in FIG. A slightly lower value. It should be noted that at 120 degrees when the V phase becomes a duty of 0% at once, the voltages of the W phase and the U phase suddenly drop.

  Control is repeated so that the operation waveforms of the U phase, V phase, and W phase are as described above.

  As shown in FIG. 11, the U-phase, V-phase, and W-phase interphase voltages have different waveforms from the sine wave, but the U-phase-V phase line voltage, V-phase-W-phase line voltage, W Since the phase-U phase line voltage has a sine waveform, the motor 13 (FIG. 14) and the fan 14 (FIG. 14) driven by the three-phase line voltage are shown in FIG. The operation is the same as in the case of the three-phase modulation method.

  However, since the W phase is constant from 0 to 60 degrees, the U phase is from 60 to 120 degrees, and the W phase is from 120 to 180 degrees, the number of PWM control operations by the inverter 15 is reduced. it can. Therefore, the power consumption of the inverter 15 is reduced.

  In addition, in 0 to 360 degrees and all the sections in which it is repeated, any of the U phase, V phase, and W phase is fixed, and the remaining two phases are modulated. Therefore, as described above, the two-phase modulation is performed.

  Further, “Semiconductor power conversion circuit”, pages 110, 111, 125, etc., published by the Institute of Electrical Engineers of Japan in March 1987, shows the same or similar technology.

  Next, the stationary phase 120 degree switching method in which the fixed section per phase is longer than the stationary phase 60 degree switching method will be described.

  The stationary phase 120 degree switching method includes an upper stationary phase 120 degree switching method for fixing the stationary phase to a high DC voltage potential, and a lower stationary phase 120 degree switching for fixing the stationary phase to a low DC voltage potential. There are two types of methods. Next, the upper stationary phase 120 degree switching method and the lower stationary phase 120 degree switching method will be described in order.

  FIG. 12 is a diagram illustrating voltage waveforms (voltage commands) of the U phase, the V phase, and the W phase in the upper stationary phase 120-degree switching method that is a two-phase modulation method. The horizontal axis represents the electrical angle [°], and the vertical axis represents the voltage duty [%].

  In FIG. 12, the U-phase is constant from 30 degrees (corresponding to [°]) to 150 degrees with an upper limit voltage of 100% duty.

  The W phase is constant from 150 degrees to 270 degrees with the upper limit voltage of 100% duty.

  The V phase is constant from the upper limit voltage of 100% duty from 270 degrees to (390) degrees.

  As described above, each of the U phase, the V phase, and the W phase is fixed at a high power supply level for each phase at an electrical angle of 2π / 3 (120 degrees).

  Further, in the section where one phase of each of the U phase, the V phase, and the W phase is fixed, the other phases are voltage differences and phases with respect to the above phases in the case of the three-phase modulation method shown in FIG. Control to take a voltage waveform that maintains the same relationship as.

  Therefore, the U-phase, V-phase, and W-phase can be Y-connected, and the three-phase AC motor can be driven with the respective line voltages.

  FIG. 13 is a diagram illustrating voltage waveforms (voltage commands) of the U phase, the V phase, and the W phase in the lower fixed phase 120-degree switching method that is a two-phase modulation method. The horizontal axis represents the electrical angle [°], and the vertical axis represents the voltage duty [%].

  In FIG. 13, the V phase is constant at a lower limit voltage of 0% duty from 90 degrees (corresponding to [°]) to 210 degrees.

  Further, the U phase is constant at a lower limit voltage of 0% duty from 210 degrees to 330 degrees.

  Further, the W phase is constant from 330 degrees to (450) degrees and from (-30) degrees to 90 degrees with a lower limit voltage of 0% duty.

  As described above, each of the U phase, the V phase, and the W phase is fixed to the low potential power supply level for each phase during an electrical angle of 2π / 3 (120 degrees).

  Further, in the section where one phase of each of the U phase, the V phase, and the W phase is fixed, the other phases are voltage differences and phases with respect to the above phases in the case of the three-phase modulation method shown in FIG. Take a voltage waveform that maintains the same relationship as.

  Therefore, it is possible to drive the three-phase motor with each line voltage with the U-phase, V-phase, and W-phase as Y connections.

  As described above, both the upper stationary phase 120 degree switching method and the lower stationary phase 120 degree switching method are sequentially fixed to the high power level or the low power level for each phase by an electrical angle of 2π / 3 (120 degrees, 120 °). Therefore, the switching loss of the inverter can be reduced.

  When the amplitude of the phase voltage becomes lower than a predetermined voltage value and the situation shown in FIG. 12 or 13 is not appropriate, the two-phase modulation method is stopped and the motor is controlled by the three-phase modulation method. There is also a method of applying a phase voltage.

  Patent Document 2 discloses the same or similar technique as described above.

  The voltage fluctuation changes due to the change of the modulation method. For example, in the fixed phase 60 ° switching method of the two-phase modulation method, there are six voltage discontinuities per rotation, so that the next multiple of 6 is affected. For example, in the case of the lower stationary phase 120 ° switching method, there are three discontinuous points 90, 210, and 330 ° in FIG. These explanations seem to contradict the above explanation that the change of the modulation method does not change as the line voltage, but the error of the modulation method is an error of several percent or less with respect to the applied voltage primary amplitude. It is almost impossible and affects sound.

  Therefore, when the modulation method is changed, the same sound reduction effect can be obtained even if the modulation method is changed by adding correction values to the phase φn and the amplitude Gn.

  Next, the configuration of a motor control device that reduces sound in modulation system switching control will be described.

  FIG. 14 is a diagram showing the internal configuration of the motor control device 11 according to the third embodiment of the present invention and the relationship among the motor control device 11, the DC power supply 12, the motor (three-phase motor) 13, and the fan 14. is there.

  In FIG. 14, the configuration of the control device 20 of the motor control device 11 has a feature as the third embodiment.

  The DC power supply 12, the motor 13, the fan 14, the inverter 15, and the DC bus current detection circuit 16 are the same as those in the first embodiment shown in FIG.

  The control device 20 includes a vector control unit 21, a PWM pulse generation unit 24, a high-order component generation unit 22, a voltage addition unit 23, a high-order component correction unit 28, and a modulation scheme selection unit 29. Is done.

  The vector control unit 21 acquires the phase current information 16A from the DC bus current detection circuit 16, calculates the motor rotation speed / phase information 21A, and outputs it to the high-order component generation unit 22 and the modulation method selection unit 29. . The vector control unit 21 also outputs a fundamental wave applied voltage command 21B to the voltage adding unit 23.

  The high-order component generation unit 22 generates a high-order component 22A based on the motor rotation speed / phase information 21A and outputs the high-order component 22A to the high-order voltage correction unit 28.

  The modulation method selection unit 29 selects the fixed phase 60 degree (or 120 degree) switching method of the two-phase modulation method or the three-phase modulation method based on the motor rotation speed / phase information 21A, and sends the modulation method selection signal 25A. This is output to the PWM pulse generator 24 and the high-order component corrector 28.

  The high-order voltage correction unit 28 corrects the high-order component from the modulation scheme information 25A and the high-order component 22A and outputs the corrected high-order component 26A to the voltage addition unit 23.

  The voltage adding unit 23 adds the fundamental wave applied voltage command 21B and the higher-order component 22A and outputs the applied voltage command 23A. The PWM pulse generator 24 generates PWM pulse information 20A based on the applied voltage command 23A and the modulation method selection signal 25A.

  With the above configuration, the resonance noise of the fan and the rotor is reduced by applying a higher voltage component in the two-phase modulation type fixed phase 60 degree switching method and the fixed phase 120 degree switching method.

  Therefore, the third embodiment has an effect of reducing the resonance noise of the fan and the rotor in addition to high efficiency by reducing the modulation method, reduction of sound, and reduction of electrical noise.

  As described above, the third embodiment has been described in the case where the voltage high-order component is added. However, the same effect as the method of adding the voltage high-order component can be expected in the method of adding the current high-order component.

  A motor control device according to a fourth embodiment of the present invention will be described. The fourth embodiment includes the higher-order component generation unit 22 and the current addition unit 26 of the second embodiment, and the higher-order component correction unit 28 and the modulation scheme selection unit 29 of the third embodiment. The implementation method is obtained by replacing the high-order voltage of the third embodiment with a high-order current.

  Next, a fifth embodiment will be described. In the present embodiment, the motor control device 11 described in the first to third embodiments is applied to the fan motor control device 108 of the outdoor unit 101 of the air conditioner 100.

  FIG. 15 is a diagram illustrating a configuration example of an air conditioner 100 according to the fifth embodiment of the present invention. 15, the air conditioner 100 includes an outdoor unit 101 that exchanges heat with the outside air, an indoor unit 102 that exchanges heat with the room, and a pipe 103 that connects the two.

  The outdoor unit 101 includes a compressor 104 that compresses a refrigerant, a heat exchanger 105 that exchanges heat with the outside air, an outdoor fan 106 that blows air to the heat exchanger 105, an outdoor fan motor 107 that rotates the outdoor fan 106, And a motor control device 108 for driving the outdoor fan motor 107. Note that the motor control device 11 of the first to fourth embodiments is applied to the motor control device 108, the outdoor fan motor 107 corresponds to the three-phase motor 13, and the outdoor fan 106 corresponds to the load 14.

  The indoor unit 102 includes a heat exchanger 109 that exchanges heat with the room, and a blower 110 that blows air into the room.

  In the fifth embodiment, as described above, the motor control device 11 of the first to fourth embodiments is applied to the air conditioner 100. That is, in the control devices (17, 18, 20) for controlling the inverter 15, a high-order component is applied or a modulation method is selected so that the fan 14 and rotor (motor) 13) Resonance noise is reduced.

  According to the fourth embodiment, it is possible to reduce the sound without using the vibration isolation rubber of the rotor part of the outdoor fan motor 107 or the vibration isolation rubber of the fan part, so that the quiet air conditioner 100 can be manufactured at low cost. Become.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, this invention is not limited to these embodiment and its deformation | transformation, There exists a design change etc. of the range which does not deviate from the summary of this invention. Well, here are some examples:

  Each configuration, function, processing unit, processing means, and the like of the present embodiment may be realized by hardware by designing a part or all of them with an integrated circuit, for example. Moreover, you may implement | achieve by the software which can change a program. Also, hardware and software may be mixed.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

  Part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  In addition, for the sake of clarity, the description has been given mainly for the case where the fan is driven as a load. However, the present invention is effective in reducing the sound caused by the structural resonance frequency, and the load is limited to the fan. Not what you want.

  The acquisition of phase current information by the DC bus current detection circuit 16 can be performed by using a general method such as the method disclosed in Japanese Patent Application Laid-Open No. 2004-48886, and does not specify a detection method.

  The vector control unit 21 is described in the above "" Examination of a new vector control method for a high-speed permanent magnet synchronous motor ", Electrotechnical D, Vol.129 (2009) No.1 pp.36-45" Realized by using general vector control such as the method proposed in "Electronic theory D, Vol.124 (2004) No.11 pp.1133-1140". It does not specify the control method.

  The IGBT is used as the switching element of the power conversion main circuit 51. However, a switching element of another semiconductor element may be used, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Further, a semiconductor element using SiC (Silicon Carbide, silicon carbide) or GaN (Gallium Nitride, gallium nitride) as the composition of the element may be used.

  In the high-order component application formula, G (ratio of higher-order wave amplitude to voltage fundamental wave amplitude) and φ (phase difference between the fundamental wave component and higher-order component) were initially described using the set values. Based on the information of the DC bus current detection circuit 16, there is a method in which the vector control unit 21 changes G and φ as appropriate according to the situation and performs optimal control.

  The gate driver 52 in FIG. 1 has a main function to increase the signal drive capability of the PWM pulse generation unit 24. Therefore, the gate driver 52 has sufficient drive capability at the output unit of the PWM pulse generation unit 24, or the gate driver. If the function 52 is built in the PWM pulse generator 24, the inverter 15 does not have to include the gate driver 52.

DESCRIPTION OF SYMBOLS 11, 108 Motor control apparatus 12 DC power supply 13 Motor, 3 phase motor, 3 phase AC synchronous motor 14 Load, fan 15 Inverter, power conversion circuit 16 DC bus current detection circuit 17, 18, 20 Control apparatus 21 Vector control section 22 High Next component generation unit 23 Voltage addition unit 24 PWM pulse generation unit 25 Command current generation unit 26 Current addition unit 27 Voltage command calculation unit 28 Higher order component correction unit 29 Modulation method selection unit 51 Power conversion main circuit 52 Gate driver 100 Air conditioning Machine 101 Outdoor unit 102 Indoor unit 103 Piping 104 Compressor 105 Heat exchanger (outdoor heat exchanger)
106 outdoor fan 107 outdoor fan motor 109 heat exchanger (indoor heat exchanger)
110 Blower

Claims (8)

An inverter connected to a DC power source, converting DC power of the DC power source into AC power of variable voltage and variable frequency, and driving and controlling the motor;
A vector control unit for calculating a voltage applied to the motor for rotationally driving a load;
A high-order component generation unit that calculates a high-order component of the fundamental wave of the applied voltage of the vector control unit;
A voltage addition unit that adds the higher-order component calculated by the higher-order component generation unit to the applied voltage calculated by the vector control unit;
A PWM pulse generator for controlling the pulse width of the inverter based on a signal from the voltage adder;
With
For the resonance sound generated by resonance of the motor and its load, the high-order component generation unit calculates a high-order component of the order represented by the ratio of the resonance frequency of the resonance sound and the motor frequency, and the voltage addition unit A motor control device characterized by adding a high-order component to an applied voltage. An inverter connected to a DC power source, converting DC power of the DC power source into AC power of variable voltage and variable frequency, and driving and controlling the motor;
A command current calculation unit for calculating a current flowing through the motor;
A high-order component generation unit that calculates a high-order component of a fundamental wave of a command current that is an output of the command current calculation unit;
A current adder for adding the higher order component calculated by the higher order component generator to the command current;
A vector control unit for calculating a voltage to be applied to the motor from the output of the current addition unit;
A PWM pulse generator for controlling the pulse width of the inverter based on the signal of the vector controller;
With
For the resonance sound generated by resonance of the motor and its load, the high-order component generation unit calculates a high-order component of the order represented by the ratio of the resonance frequency of the resonance sound to the motor frequency, and the current addition unit A motor control device characterized by adding a high-order component to a command current. An inverter connected to a DC power source, converting DC power of the DC power source into AC power of variable voltage and variable frequency, and driving and controlling the motor;
A vector control unit for calculating a voltage applied to the motor for rotationally driving a load;
A high-order component generation unit that calculates a high-order component of the fundamental wave of the applied voltage of the vector control unit;
A PWM pulse generation unit having a plurality of modulation methods including a fixed two-phase modulation method, and performing pulse width control of the inverter based on a signal of the voltage addition unit;
A high-order component correction unit that corrects the high-order component corresponding to a plurality of modulation methods;
A voltage addition unit that adds the higher-order component calculated by the higher-order component correction unit to the applied voltage calculated by the vector control unit;
With
For the resonance sound generated by resonance between the motor and its load, the high-order component generator calculates a high-order component of the order expressed by the ratio of the resonance frequency of the resonance sound to the motor frequency, and the high-order component is corrected. The motor control apparatus, wherein the high-order component is added to the applied voltage by the voltage adding unit. An inverter connected to a DC power source, converting DC power of the DC power source into AC power of variable voltage and variable frequency, and driving and controlling the motor;
A command current calculation unit for calculating a current flowing through the motor;
A high-order component generation unit that calculates a high-order component of a fundamental wave of a command current that is an output of the command current calculation unit;
A high-order component correction unit that corrects the high-order component corresponding to a plurality of modulation methods;
A current addition unit that adds the higher-order component corrected by the higher-order component correction unit to the command current;
A vector control unit for calculating a voltage to be applied to the three-phase motor from an output of the current adding unit;
A PWM pulse generator having a plurality of modulation schemes including a fixed two-phase modulation scheme, and performing pulse width control of the inverter based on a signal of the vector controller;
With
For the resonance sound generated by resonance of the motor and its load, the high-order component generation unit calculates a high-order component of the order represented by the ratio of the resonance frequency of the resonance sound and the motor frequency,
The motor control apparatus according to claim 1, wherein the current addition unit adds the high-order component corrected by the high-order component correction unit to the command current according to a modulation method.   5. The motor control device according to claim 1, wherein an amplitude of the higher-order component is 5% or less of an amplitude of the fundamental wave.   6. The motor control device according to claim 1, wherein the high-order component is a 3 m-order fundamental wave (m = 1, 2, 3,...).   The motor control device according to claim 1, wherein the load of the three-phase motor is a fan. An air conditioner equipped with the motor control device according to any one of claims 1 to 7.