KR20150121952A - Motor driving device and air conditioner including the same - Google Patents

Abstract

The present invention relates to an electric motor drive apparatus and an air conditioner having the same. An electric motor drive apparatus according to an embodiment of the present invention includes an inverter that has a plurality of switching elements and converts a pulsating power source to output a converted DC power source to a motor and a control unit that controls the inverter, , A first mode for performing grid current shaping or a second mode for not performing grid current shaping based on the speed and torque of the motor. As a result, it becomes possible to reduce the harmonics and improve the motor efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor driving apparatus and an air conditioner having the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor driving apparatus and an air conditioner having the same, and more particularly, to an electric motor driving apparatus capable of reducing harmonics and improving motor efficiency in a motor driving apparatus using a capacitor of a small capacity, will be.

The air conditioner is installed to provide a comfortable indoor environment for humans by discharging cold air to the room to adjust the room temperature and purify the room air to create a pleasant indoor environment. Generally, the air conditioner includes an indoor unit which is constituted by a heat exchanger and installed in a room, and an outdoor unit which is constituted by a compressor, a heat exchanger and the like and supplies the refrigerant to the indoor unit.

On the other hand, an electric motor is used in an air conditioner. Recently, various methods for efficient power consumption have been proposed in consideration of environmental problems. Accordingly, the use of a synchronous motor (SM), particularly a permanent magnet synchronous motor (PMSM) using a permanent magnet, is increasing.

On the other hand, when driving an electric motor, a capacitor of a low capacity is being used in order to reduce manufacturing costs. However, when a capacitor having a small capacity is used, there is a problem that the voltage across the capacitor is pulsated, and as a result, harmonics of the system current are increased.

An object of the present invention is to provide an electric motor drive apparatus capable of reducing harmonics and improving motor efficiency in a motor drive apparatus using a capacitor of a low capacity and an air conditioner having the same.

According to an aspect of the present invention, there is provided an electric motor drive apparatus including an inverter that includes a plurality of switching elements and converts pulsating pulsating power to output a converted DC power to a motor, And the control unit controls to operate in a first mode for performing grid current shaping or a second mode for not performing grid current shaping based on the speed and torque of the motor.

According to another aspect of the present invention, there is provided an air conditioner including a compressor for compressing refrigerant, a heat exchanger for performing heat exchange using compressed refrigerant, a compressor motor drive device for driving a motor in the compressor, Wherein the compressor motor driving apparatus includes an inverter that has a plurality of switching elements and converts the pulsating power supply to output the converted DC power to the motor and a control unit that controls the inverter, Based on the speed and torque of the motor, in a first mode for performing grid current shaping or in a second mode for not performing grid current shaping.

According to an embodiment of the present invention, an electric motor driving apparatus and an air conditioner having the same include a first mode for performing a grid current shaping or a second mode for performing grid current shaping 2 mode, it is possible to reduce the harmonics and improve the motor efficiency.

Particularly, when the motor output is higher than a predetermined value, the harmonics are reduced by the grid current shaping, and when the motor output is less than the predetermined value, the motor efficiency is maximized without the grid current shaping, do.

On the other hand, since it is possible to use a small-capacity film capacitor having a long life, the reliability of the motor drive device is improved, and the manufacturing cost and the volume are reduced.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.
2 is a schematic view of the outdoor unit and the indoor unit of FIG.
3 is a circuit diagram showing an example of a motor drive apparatus according to an embodiment of the present invention.
4 is an internal block diagram of the control unit of FIG.
5 is a diagram illustrating a dc voltage stage according to the capacitance of the capacitor of FIG.
6 is a diagram illustrating the first mode and the second mode of the speed and torque of the electric motor.
7 is an internal block diagram of the control unit of FIG. 3 according to an embodiment of the present invention.
8A is an internal block diagram of the first mode operation unit of FIG.
8B is an internal block diagram of the second mode operation unit of FIG.
9 is an internal block diagram of the power command generation unit of FIG. 8A.
10A illustrates the waveform of the dc voltage and the grid current according to the first mode.
FIG. 10B illustrates waveforms of the dc voltage and the grid current according to the second mode.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The suffix "module" and " part "for components used in the following description are given merely for convenience of description, and do not give special significance or role in themselves. Accordingly, the terms "module" and "part" may be used interchangeably.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.

The air conditioner 100 according to the present invention may include an indoor unit 31 and an outdoor unit 21 connected to the indoor unit 31 as shown in FIG.

The indoor unit 31 of the air conditioner is applicable to any of the stand-type air conditioner, the wall-mounted air conditioner, and the ceiling type air conditioner, but the stand type indoor unit 31 is exemplified in the figure.

Meanwhile, the air conditioner 100 may further include at least one of a ventilator, an air purifier, a humidifier, and a heater, and may operate in conjunction with the operation of the indoor unit and the outdoor unit.

The outdoor unit 21 includes a compressor (not shown) that receives refrigerant and compresses the refrigerant, an outdoor heat exchanger (not shown) that exchanges heat between the refrigerant and outdoor air, an accumulator that extracts the gas refrigerant from the supplied refrigerant, And a four-way valve (not shown) for selecting the flow path of the refrigerant according to the heating operation. In addition, a number of sensors, valves, oil recovery devices, and the like are further included, but a description thereof will be omitted below.

The outdoor unit (21) operates the compressor and the outdoor heat exchanger to compress or heat-exchange the refrigerant according to the setting to supply the refrigerant to the indoor unit (31). The outdoor unit 21 can be driven by a demand of a remote controller (not shown) or the indoor unit 31. At this time, as the cooling / heating capacity is changed corresponding to the indoor unit to be driven, the number of operation of the outdoor unit and the number of operation of the compressor installed in the outdoor unit can be varied.

At this time, the outdoor unit 21 supplies the compressed refrigerant to the indoor unit 310 connected thereto.

The indoor unit (31) receives the refrigerant from the outdoor unit (21) and discharges the cold air to the room. The indoor unit 31 includes an indoor heat exchanger (not shown), an indoor unit fan (not shown), an expansion valve (not shown) to which refrigerant supplied is expanded, and a plurality of sensors (not shown).

At this time, the outdoor unit 21 and the indoor unit 31 are connected to each other via a communication line to transmit and receive data. The outdoor unit and the indoor unit are connected to a remote controller (not shown) by wire or wireless, can do.

A remote controller (not shown) is connected to the indoor unit 31, and inputs a user's control command to the indoor unit, and receives and displays the status information of the indoor unit. At this time, the remote controller can communicate by wire or wireless according to the connection form with the indoor unit.

2 is a schematic view of the outdoor unit and the indoor unit of FIG.

Referring to the drawings, an air conditioner 100 is roughly divided into an indoor unit 31 and an outdoor unit 21.

The outdoor unit 21 includes a compressor 102 for compressing the refrigerant, a compressor 102b for driving the compressor, an outdoor heat exchanger 104 serving to dissipate the compressed refrigerant, An outdoor fan 105 which is disposed at one side of the heat exchanger 104 and includes an outdoor fan 105a for accelerating the heat radiation of the refrigerant and an electric motor 105b for rotating the outdoor fan 105a and an outdoor fan 105 for expanding the condensed refrigerant An accumulator 103 for temporarily storing the gasified refrigerant to remove moisture and foreign substances, and then supplying a refrigerant with a predetermined pressure to the compressor, a compressor 106 for compressing the refrigerant, a cooling / heating switching valve 110 for changing the flow path of the compressed refrigerant, And the like.

The indoor unit 31 includes an indoor heat exchanger 109 disposed inside the room and performing a cooling / heating function, an indoor fan 109a disposed at one side of the indoor heat exchanger 109 for promoting heat radiation of the refrigerant, And an indoor air blower 109 composed of an electric motor 109b for rotating the fan 109a.

At least one indoor heat exchanger 109 may be installed. At least one of an inverter compressor and a constant speed compressor may be used as the compressor 102. [

Further, the air conditioner 100 may be constituted by a cooling unit that cools the room, or a heat pump that cools or heats the room.

The compressor 102 in the outdoor unit 21 of Fig. 1 can be driven by a compressor motor drive apparatus (200 in Fig. 3) that drives the compressor motor 250. [

3 is a circuit diagram showing an example of a motor drive apparatus according to an embodiment of the present invention.

3 includes a rectifier 210, an inverter 220, a controller 230, a grid current detector A, a dc voltage converter (not shown) The detection unit B, the DC capacitor C, the motor current detection unit E, and the grid voltage detection unit F. [ 3 may further include reactors L1 and L2 and the like.

A reactor (L1, L2) may perform an action, such as, commercial AC power source (205, v _g) and is arranged between the rectifying section 210, a noise removal.

The system current detection section A can detect the system current i _g input from the commercial AC power supply 205. [ For this purpose, a CT (current trnasformer), a shunt resistor, or the like may be used as the system current detector A. The detected system current i _g is a discrete signal in the form of a pulse and can be input to the controller 230 for power control.

Grid voltage detector (F) is, it is possible to detect a system voltage (v _g) is input from the commercial AC power source 205. For this purpose, the system voltage detector F may include a resistance element, an amplifier, and the like. The detected system voltage v _g is a discrete signal in the form of a pulse and can be input to the controller 230 for power control.

The rectifying section 210 rectifies and outputs the commercial AC power source 205 through the reactors L1 and L2. For example, the rectifying unit 210 may include a full bridge diode having four diodes connected thereto, but various modifications are possible.

The capacitor C stores the input power. In the figure, one element is exemplified by the DC short-circuit capacitor C, but a plurality of elements are provided to secure the element stability.

On the other hand, the DC short-circuit capacitor C in the present specification may be a small-capacity capacitor, and it may be a capacitorless type capacitor. That is, the capacitor C may be a film type capacitor, not an electrolytic capacitor. By using such a capacitorless type capacitor, the stability of the electric motor drive apparatus is improved, and the manufacturing cost and the volume of the capacitor are reduced.

On the other hand, since both ends of the capacitor C are stored with DC power, they may be referred to as a dc stage or a dc link stage.

the dc short voltage detection unit B can detect the dc short voltage Vdc at both ends of the capacitor C. [ For this purpose, the dc voltage detection unit B may include a resistance element, an amplifier, and the like. The detected dc short voltage Vdc may be input to the control unit 230 for generation of the inverter switching control signal Sic as a discrete signal in the form of a pulse.

The inverter 220 includes a plurality of inverter switching elements and can convert the rectified power supply Vdc into three-phase AC power sources va, vb, vc having a predetermined frequency and output the three-phase power to the three-phase motor 250.

The inverter 220 includes a pair of upper arm switching elements Sa, Sb and Sc and lower arm switching elements S'a, S'b and S'c connected in series to each other, The switching elements are connected to each other in parallel (Sa & S a, Sb & S'b, Sc & S'c). Diodes are connected in anti-parallel to each switching element Sa, S'a, Sb, S'b, Sc, S'c.

The switching elements in the inverter 220 perform ON / OFF operations of the respective switching elements based on the inverter switching control signal Sic from the controller 230. [ Thus, the three-phase AC power source (va, vb, vc) having a predetermined frequency is outputted to the three-phase motor 250.

The control unit 230 can control the switching operation of the inverter 220. [ To this end, the control unit 230 can receive the output current (i _o ) flowing to the motor detected by the motor current detection unit (E).

The control unit 230 outputs the inverter switching control signal Sic to the inverter 220 to control the switching operation of the inverter 220. [ Inverter switching control signal (Sic) is a switching control signal for PWM, and output is generated based on the output value of the current detected by the motor current detector (E) (i _o). The detailed operation of the output of the inverter switching control signal Sic in the controller 230 will be described later with reference to FIG.

It detects the motor current detector (E), the inverter 220 and the output current (i _o) flowing between a three-phase motor 250. That is, the current flowing in the three-phase motor 250 is detected. The motor current detection unit E can detect all of the output currents ia, ib, ic of each phase, or can detect the output currents of the two phases using a three-phase balance.

The motor current detection unit E may be located between the inverter 220 and the three-phase motor 250. For current detection, a current transformer (CT), a shunt resistor, or the like may be used.

When a shunt resistor is used, three shunt resistors are placed between the inverter 220 and the three-phase motor 250, or three down-arm switching elements S'a, S'b, S'c To be connected to each other. On the other hand, it is also possible to use two shunt resistors using three phase equilibrium. On the other hand, when one shunt resistor is used, the shunt resistor may be disposed between the capacitor C and the inverter 220 described above.

The output (i _o), a current detection is, as discrete signals (discrete signal) of the pulse type, may be applied to the controller 230, is generated by the inverter switching control signal (Sic) based on the detected output current (io) do. In the output current detection (i _o) will now be described in that the three-phase output currents (ia, ib, ic) of the.

On the other hand, the three-phase motor 250 has a stator and a rotor, and each phase alternating current power of a predetermined frequency is applied to a coil of a stator of each phase (a, b, c phase) .

The three-phase electric motor 250 may be, for example, a Surface Mounted Permanent Magnet Synchronous Motor (SMPMSM), an Interior Permanent Magnet Synchronous Motor (IPMSM) A synchronous reluctance motor (Synrm), and the like.

Among them, SMPMSM and IPMSM are permanent magnet applied Permanent Magnet Synchronous Motor (PMSM), and Synrm is characterized by having no permanent magnet.

Meanwhile, in connection with the embodiment of the present invention, the control unit 230 may control the first mode for performing the grid current shaping or the second mode for performing the grid current shaping based on the speed and torque of the motor , It can be controlled to operate.

In particular, the controller 230 may perform the grid current shaping such that the grid current corresponds to the ripple voltage in the first mode of operation.

The control unit 230 includes a mode selection unit (410 in FIG. 7) that selects either the first mode or the second mode based on the speed calculated based on the output current flowing to the motor and the torque command value .

The control unit 230 may further include a torque command generation unit (325 in Fig. 7) that generates a torque command value based on the calculated speed and the speed command value.

The control unit 230 may further include a first mode operation unit 420 (FIG. 7) for operating the motor in the first mode and a second mode operation unit 430 (FIG. 7) for operating the motor in the second mode .

The first mode operation section (420 in Fig. 7) includes a current command generation section (330 in Fig. 8A) for generating a current command value based on the torque command value, and a current command value generation section A power command generator (520 in FIG. 8A) for generating a power command value based on the torque command value; a power controller (520 in FIG. 8A) for generating a second voltage command value based on the power command value; (525 in Fig. 8A) and a switching control signal output unit (360 in Fig. 8A) for outputting a switching control signal based on the first and second voltage command values. At this time, the system current control, that is, shaping, of the inverter is performed in consideration of the pulsating dc voltage by the second voltage command value based on the power command generator (520 in Fig. 8A) and the power controller (525 in Fig. Lt; / RTI >

The second mode operation section (430 in FIG. 7) includes a current command generation section (330 in FIG. 8B) for generating a current command value and a voltage command generation section (340 in FIG. 8B) for generating a voltage command value based on the current command value And a switching control signal output unit (360 in Fig. 8B) for outputting a switching control signal based on the voltage command value. In this case, the system current control considering the pulsating dc voltage is not performed, but the motor can be operated at the maximum efficiency corresponding to the load.

On the other hand, the control unit 230 determines whether or not the system current i _g detected by the system current detection unit A, the system voltage v _g detected by the system voltage detection unit F, on the basis of the dc terminal voltage (Vdc), the output current (i _o) detected by the motor current detector (E), and performs power control.

4 is an internal block diagram of the control unit of FIG.

4, the control unit 230 includes an axis transformation unit 310, a position estimation unit 320, a current command generation unit 330, a voltage command generation unit 340, an axis transformation unit 350, And a switching control signal output unit 360.

The axial conversion unit 310 receives the three-phase output currents ia, ib, ic detected by the output current detection unit E and converts the three-phase output currents ia, ib, ic into the two-phase currents iα, iβ in the stationary coordinate system.

On the other hand, the axis converting unit 310 can convert the two-phase current i ?, i? Of the still coordinate system into the two-phase current id, iq of the rotating coordinate system.

)에 기초하여, 추정된 속도(

)를 추청할 수 있다.The position estimating unit 320 receives the two-phase currents iα and iβ of the stationary coordinate system and the two-phase voltages vα and vβ of the stationary coordinate system and estimates the rotor position θ. In addition, the position estimating unit 320 estimates the position

), The estimated speed (

).

The two-phase currents i alpha and i beta of the stationary coordinate system at this time can be input from the axis converter 310 and the two phase voltages v alpha and v beta of the stationary coordinate system are input to the dc stage from the dc stage voltage detector B The voltage (Vdc), and the switching operation state of the inverter (220). For example, the three-phase output voltages (va, vb, vc) are calculated by a predetermined relational expression according to the dc voltage source Vdc from the dc voltage detection unit B and the switching operation state of the inverter 220 , And can be converted into the two-phase voltage (v [alpha], v [beta]) of the stationary coordinate system again in the axis conversion unit 310. [

)와 추정된 속도(

)를 출력할 수 있다.On the other hand, the position estimating unit 320 estimates the position (

) And the estimated speed (

Can be output.

)를 연산할 수 있다. 즉, 위치 신호에 기반하여, 시간에 대해, 나누면, 속도를 연산할 수 있게 된다. 이하에서는, 위치 추정부(320)를 중심으로 기술한다.4, there is illustrated a sensorless type position estimating unit 320 that does not have a separate sensor for sensing the rotor position. Alternatively, when a position sensing sensor such as a Hall sensor is used, The controller 320 can be replaced with a speed calculator (not shown). That is, when a position signal sensed by the hall sensor is input to a speed calculating unit (not shown), a speed

) Can be calculated. That is, based on the position signal, it is possible to calculate the speed by dividing it with respect to time. Hereinafter, the position estimating unit 320 will be mainly described.

)와 연산된 속도(

)를 출력할 수 있다.On the other hand, the position estimating unit 320 calculates the position (H) based on the position signal H of the input rotor

) And the calculated speed (

Can be output.

)와 속도 지령치(ω^* _r)에 기초하여, 전류 지령치(i^* _q)를 생성한다. 예를 들어, 전류 지령 생성부(330)는, 연산 속도(

)와 속도 지령치(ω^* _r)의 차이에 기초하여, PI 제어기(335)에서 PI 제어를 수행하며, 전류 지령치(i^* _q)를 생성할 수 있다. 도면에서는, 전류 지령치로, q축 전류 지령치(i^* _q)를 예시하나, 도면과 달리, d축 전류 지령치(i^* _d)를 함께 생성하는 것도 가능하다. 한편, d축 전류 지령치(i^* _d)의 값은 0으로 설정될 수도 있다. On the other hand, the current command generation unit 330 generates the current command

(I ^* _q ) on the basis of the speed command value? ^* _R and the speed command value? ^* _R. For example, the current command generation section 330 generates the current command

The PI controller 335 performs the PI control based on the difference between the speed command value? ^* _R and the speed command value? ^* _R , and generates the current command value i ^* _q . In the figure, the q-axis current command value (i ^* _q ) is exemplified by the current command value, but it is also possible to generate the d-axis current command value (i ^* _d ) unlike the figure. On the other hand, the value of the d-axis current command value i ^* _d may be set to zero.

On the other hand, the current command generation section 330 may further include a limiter (not shown) for limiting the current command value (i ^* _q ) so that the current command value (i ^* _q ) does not exceed the allowable range.

Next, the voltage command generating unit 340 generates the voltage command generating unit 340 with the d-axis and q-axis currents (i _d , i _q ) axially transformed into the two-phase rotational coordinate system in the axial converting unit and the current command value based on ^{_{i * d, i * q)}} , and generates a d-axis, q-axis voltage command value ^{_{(v * d, v * q}} ). For example, the voltage command generation unit 340 performs PI control in the PI controller 344 based on the difference between the q-axis current (i _q ) and the q-axis current command value (i ^* _q ) It is possible to generate the axial voltage command value v ^* _q . The voltage command generation unit 340 performs PI control in the PI controller 348 based on the difference between the d-axis current i _d and the d-axis current command value i ^* _d , It is possible to generate the command value v ^* _d . On the other hand, the value of the d-axis voltage command value v ^* _d may be set to 0 corresponding to the case where the value of the d-axis current command value i ^* _d is set to zero.

The voltage command generator 340 may further include a limiter (not shown) for limiting the level of the d-axis and q-axis voltage command values v ^* _d and v ^* _q so as not to exceed the permissible range .

On the other hand, the generated d-axis and q-axis voltage command values (v ^* _d and v ^* _q ) are input to the axial conversion unit 350.

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis transforming unit 350 transforms the position calculated by the position estimating unit 320

) And the d-axis and q-axis voltage command values (v ^* _d , v ^* _q ).

)가 사용될 수 있다.First, the axis converting unit 350 performs conversion from a two-phase rotating coordinate system to a two-phase stationary coordinate system. At this time, the position calculated by the position estimating unit 320

) Can be used.

Then, the axial conversion unit 350 performs conversion from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axial conversion section 2050 outputs the three-phase output voltage instruction values v ^* a, v ^* b, v ^* c.

The switching control signal output section 360 generates the switching control signal Sic for inverter according to the pulse width modulation (PWM) method based on the three-phase output voltage instruction values v ^* a, v ^* b and v ^* And outputs it.

The output inverter switching control signal Sic may be converted into a gate driving signal in a gate driver (not shown) and input to the gate of each switching element in the inverter 220. [ As a result, the switching elements Sa, S'a, Sb, S'b, Sc, and S'c in the inverter 220 perform the switching operation.

5 is a diagram illustrating a dc voltage stage according to the capacitance of the capacitor of FIG.

First, FIG. 5A illustrates the dc short-circuit voltage Vdc1 when an electrolytic capacitor having a large capacitance is used as the dc-short capacitor C. In FIG.

Next, Fig. 5B illustrates the dc short-circuit voltage Vdc2 when a small-capacity film-type capacitor is used as the dc short-circuit capacitor C. Fig.

As shown in Fig. 5B, when the capacitor of the capacitorless type is used, since the capacitance is small, the smoothing function is deteriorated, and the fluctuation of the dc short-circuit voltage becomes much larger than that of Fig. 5A.

Equation 1 below shows the relationship between the input power Pg, the dc short-circuit power Pdc, and the inverter output power Pinv.

,

는 각각 전동기에 인가되는 전압 벡터와 전동기에 흐르는 전류 벡터를 의미하며, θ_vi는 전압 벡터(

)와 전류 벡터(

)의 위상 차이를 나타낸다.Here, Cdc represents a dc-stage capacitor,

,

Denotes a voltage vector applied to the motor and a current vector flowing to the motor, and? _Vi denotes a voltage vector

) And the current vector (

) ≪ / RTI >

In the case of a general inverter, since the capacity of the dc short-circuit capacitor C in FIG. 5A is large enough to compensate for the difference in power, the desired inverter output power Pinv can be obtained without considering the input power Pg Can be output.

5 (b), the magnitude of the dc short-circuit power Pdc is limited by the capacity of the dc short-circuit capacitor C, so that the input power Pg and the inverter output power Pinv) can not be sufficiently compensated.

Particularly, when a single-phase input power source is used, a large pulsation component of the input power Pg generated due to the single-phase input power source may remain in the inverter output power Pinv to a large extent, resulting in pulsation of the motor output.

In the embodiment of the present invention, in the motor drive apparatus using the capacitorless type capacitor, it is possible to drive the motor in consideration of the dc step voltage (Vdc) with high fluctuation, Suggest a plan.

6 is a diagram illustrating the first mode and the second mode of the speed and torque of the electric motor.

Referring to the drawings, the present invention is divided into a first mode for performing current shaping and a second mode for not performing current shaping according to the speed and torque of the electric motor 250.

Particularly, since the product of the speed and the torque of the electric motor 250 is proportional to the output of the motor, when the output of the motor is greater than or equal to a predetermined value, it operates in the first mode, can do.

Particularly, when the motor output is large, the harmonic component of the system current can be increased in accordance with the short dc pulse, so that the current shaping is performed in order to reduce harmonic components. That is, the inverter can be controlled in consideration of the pulsating dc stage.

On the other hand, when the motor output is small, the dc short pulsation is relatively small, so that the harmonic component of the grid current can be negligible. At this time, the efficiency of the motor can be improved by controlling the inverter so that the efficiency of the motor is maximized.

7 is an internal block diagram of the control unit of FIG. 3 according to an embodiment of the present invention, FIG. 8A is an internal block diagram of the first mode operation unit of FIG. 7, and FIG. 8B is an internal block diagram of the second mode operation unit of FIG. to be.

Referring to the drawings, in accordance with an embodiment of the present invention, the controller 230 may be configured to perform a first mode for performing grid current shaping, or a second mode for performing grid current shaping, Mode to operate.

In particular, the controller 230 may perform the grid current shaping such that the grid current Ig corresponds to the ripple voltage in the first mode of operation.

), 및 토크 지령치(T^*)에 기초하여, 제1 모드와 제2 모드 중 어느 하나를 선택하는 모드 선택부(410)를 구비할 수 있다.The control unit 230 compares the speed calculated based on the output current Io flowing through the motor

, And a torque command value T ^* , based on the torque command value T ^* and the torque command value T ^* .

)와 속도 지령치(ω^* _r)에 기초하여 토크 지령치(T^*)를 생성하는 토크 지령 생성부(325)를 더 포함할 수 있다.The control unit 230 compares the calculated speed (

And a torque command generation section 325 for generating a torque command value T ^* based on the speed command value? ^* _R and the speed command value? ^* _R.

The control unit 230 may further include a first mode operation unit 420 for operating the motor in the first mode and a second mode operation unit 430 for operating the motor in the second mode.

The first mode operation section 420 includes a current command generation section 330 for generating a current command value I ^* based on the torque command value T ^* and a current command value generation section 330 for generating a current command value I ^* A voltage command generation section 340 for generating a voltage command value V ^* ₁ , a power command generation section 520 for generating a power command value P ^* based on the torque command value T ^* , a power command value P ^{* *)} and, by a switching control signal based on the second (and V ^- _2), a power controller 525 for generating the first and second voltage command value ((V ^- _1, V ^- ₂₎ voltage command value based on the ( The second voltage command value V ^* ₂ based on the power command generation unit 520 and the power controller 525 may be used to generate pulsating the system current control of the inverter 220, that is, shaping, can be performed in consideration of the dc short voltage Vdc.

The second mode operation unit 430 includes a current command generation unit 330 that generates a current command value I ^* and a voltage command generation unit 340 that generates a voltage command value V ^* based on the current command value. And a switching control signal output unit 360 for outputting the switching control signal Sic based on the voltage command value V ^* . In this case, the system current control considering the pulsating dc voltage is not performed, but the motor can be operated at the maximum efficiency corresponding to the load.

On the other hand, the torque command generation section 325 in the control section 230 can output the torque command value T ^* for rotation of the electric motor based on the speed command and the calculated speed value. In particular, the torque command generation section 325 can output an average torque command value. On the other hand, the calculated speed can be calculated based on the above-described output current (i _o ) flowing to the electric motor, or the position signal.

The current command generation section 330 can generate the current command value I ^* based on the torque command value T ^* . Here, the current command value I ^* may be a meaning including a d-axis current command value and a q-axis current command value in the synchronous coordinate system.

Next, the voltage command generation section 340 can generate the voltage command value V ^* based on the current command value I ^* and the output current flowing to the actual motor. Here, the voltage command value V ^* may be a meaning including a d-axis voltage command value and a q-axis voltage command value in the synchronous coordinate system.

Next, the switching control signal output section 360 can output a switching control signal for controlling the switching elements in the inverter 120 based on the voltage command value V ^* .

8B is a mode which is performed when the motor output is less than a predetermined value and is a control mode that does not consider the dc step voltage and in particular the voltage Vdc stored in the capacitor C Method.

Accordingly, when the capacitor C of the capacitorless type is used, the fluctuation in the magnitude of the dc voltage is small, so that the efficiency at the time of driving the motor can be maximized.

On the other hand, when the output of the motor is increased, driving in the second mode as shown in FIG. 8B results in no power control and precise power compensation control.

In particular, due to the limitation of the PI controller in the voltage command generator 340, the output voltage limit may be exceeded, which may cause a reduction of the power factor and a limitation of the operation range of the motor. Accordingly, when the motor output is equal to or greater than a predetermined value, the first mode in which power control is possible is operated.

8A includes a torque command generation section 325, a power command generation section 520, a power controller 525, a current command generation section 330, a voltage command generation section 340, an adder 555 ), And a switching control signal output unit 360. The axis transformation unit 310, the axis transformation unit 350, and the position estimation unit 320 described in FIG. 4 may be further included. Hereinafter, the units described in Fig. 8A will be mainly described.

)와 속도 지령치(ω^* _r)에 기초하여, 전동기의 회전을 위한, 토크 지령치(T^*)를 출력할 수 있다. 특히, 토크 지령 생성부(325)는, 평균 토크 지령치를 출력할 수 있다. 한편, 연산 속도(

)는, 상술한, 전동기(250)에 흐르는 출력 전류(i_o), 또는 위치 신호에 기반하여, 연산될 수 있다.The torque command generation section 325 generates the torque command

And the torque command value T ^* for rotation of the electric motor based on the speed command value? ^* _R and the speed command value? ^* R. In particular, the torque command generation section 325 can output an average torque command value. On the other hand,

Can be calculated based on the above-described output current (i _o ) flowing to the electric motor 250, or the position signal.

The current command generation section 330 can generate the current command value I ^* based on the torque command value T ^* . Here, the current command value I ^* may be a meaning including a d-axis current command value and a q-axis current command value in the synchronous coordinate system.

The voltage command generation section 340 can generate the first voltage command value V ^* ₁ based on the current command value I ^* and the output current flowing to the actual motor. Here, the first voltage command value V ^* ₁ may be a meaning including a d-axis voltage command value and a q-axis voltage command value in the synchronous coordinate system.

On the other hand, in relation to the weak field current, the current command generation section 330 can output the weak field control current command value to the voltage command generation section 340 during weak field control.

), 및 dc 단 전압 검출부에서 검출된 dc 단 전압(Vdc)에 기초하여, 출력 전력 지령치(P^*)를 생성하여 출력한다. 특히, 인버터(220)에서 출력 가능한 인버터 출력 전력 지령치(P^*inv)를 생성하여 출력한다. 본 명세서에서는, 전력 지령 생성부(520)에서 생성되는 출력 전력 지령치에 대해, P^* 와 P^*inv 를 혼용하여 사용하나, 그 의미는 동일하다.On the other hand, the power command generation unit 520 generates the power command Vg, the torque command value T ^*

) And the dc step voltage (Vdc) detected by the dc step voltage detecting unit, and outputs the generated output power instruction value (P ^* ). In particular, the inverter output power command value (P ^* inv) output from the inverter 220 is generated and output. In this specification, for the output power command value generated by the power command generation unit 520, P ^* and P ^* inv Are used in combination, but the meaning is the same.

)와, 계통 전압(Vg)의 위상을 이용하여, 입력 전력의 순시치(P^*g)를 산출한다.Specifically, the electric power command generation unit 520 generates the electric power command based on the torque command value T ^* , which is the output of the torque command generation unit 325,

(P ^* g) of the input power by using the phase of the power supply voltage Vg and the phase of the system voltage Vg.

In order to drive the capacitor-less inverter, the power change due to the dc step voltage variation must be considered. Therefore, in addition to the instantaneous value (P ^* g) of the input power, (P ^* dc). The power command generation unit 520 generates an inverter output power command value P ^* inv using the instantaneous value P ^* g of the input power and the instantaneous value of the dc step power P ^* dc .

9, the system voltage Vg detected by the system voltage detection unit F is supplied to the zero crossing detection unit 605 and the phase detection unit (PLL) 607 in the power command generation unit 520 Can be input.

The zero crossing point detected by the zero crossing detection unit 605 can be input to the torque command generation unit 325 and used.

The phase detection unit (PLL) 607 detects the phase? G by using the system voltage Vg detected by the system voltage detection unit F. [ The detected phase [theta] g is used in the first unit 609. [

)를 입력받아, 이를 승산한다. 이에 의해, 입력 전력(P'g)이 연산될 수 있다. 제3 유닛(612)에 입력된다.On the other hand, the second unit 611 calculates the torque command value T ^*

), And multiplies it. Thereby, the input power P'g can be calculated. And is input to the third unit 612.

The third unit 612 multiplies the calculated input power P'g by the sinusoidal function 3sin ² (? G) output from the first unit 609. Thus, the input power instantaneous value P ^* g is calculated.

On the other hand, the fourth unit 614 generates the dc single power instantaneous value P ^* dc, which is calculated by the capacitance Cdc of the capacitor C and the dc short voltage Vdc detected by the dc short voltage detection unit And outputs it.

The fifth unit 616 subtracts the dc step voltage command value P ^* dc from the input power instantaneous value P ^* g. Then, the difference between the input power instantaneous value (P ^* g) and the dc single-phase electric power instantaneous value (P ^* dc), that is, the inverter output power command value (P ^* inv) is output. The inverter output power command value (P ^* inv) may be called an inverter power instantaneous value.

The following Equation 2 illustrates a method of calculating the inverter output power command value P ^* inv calculated in the power command generator 520 of FIG. 9 described above.

Here, Vg denotes a system voltage, Ig denotes a grid current, Vdc denotes a dc short-circuit voltage, and Cdc denotes a capacitance of the capacitor C. Then, wgt corresponds to the above-mentioned phase? G.

The power command value P ^* output from the power command generation unit 520 of FIG. 8A and the inverter output power command value P ^* inv of FIG. 9 mean the same value.

Next, the power controller 525 performs power control based on the input inverter output power command value P ^* inv.

The power controller 525 can generate the second voltage command value V ^* ₂ based on the inverter output power command value P ^* inv. Here, the second voltage instruction value V ^* ₂ is a compensation voltage instruction value for compensating the first voltage instruction value V ^* ₁ in which the dc step voltage is not taken into consideration.

The adder 555 adds the first voltage command value V ^* ₁ and the second voltage command value V ^* ₂ and outputs the result. That is, the inverter output voltage command value V ^* 3 is output as the third voltage command value.

Then, the switching control signal output section 360 generates and outputs a switching control signal based on the third voltage command value V ^* 3.

The detailed operation of the power controller 525 is as follows.

On the other hand, the magnitude of the inverter power (Pinv) can be determined by the inner product of the motor output current vector and the inverter output voltage vector. Accordingly, the motor current vector or the inverter output voltage vector can be adjusted to obtain the desired inverter power.

Among these methods, the method of adjusting the motor output current vector may not be able to quickly follow the inverter output power command value due to the delay generated in the voltage command generator 340. [ Also, in a given motor output current situation, the inverter power control can not be precisely controlled since the necessary voltage magnitude is different in order to match the required inverter output voltage magnitude with the inverter power magnitude.

Accordingly, in this specification, a method of adjusting the inverter output voltage vector is presented.

According to the embodiment of the present invention, the power controller 525 generates the second voltage command value V ^* ₂ for compensating the first voltage command value V ^* ₁ corresponding to the dc terminal voltage. Accordingly, control of the inverter output voltage becomes possible through the power controller 525. [

The inverter output voltage vector may affect not only the output power of the inverter but also the change of the motor current vector. Therefore, it is necessary to minimize the influence on the voltage command generator 340 by selecting an appropriate voltage vector.

The power controller 525 can select any one of the various inverter output voltage command vectors in consideration of the inverter output power command value.

)에 평행하며, 최종 전압 지령치의 벡터(

)가, 제1 전압 지령치의 벡터(

)에 가장 가까운 벡터가 되도록 하는, 벡터를, 보상 전압 지령치의 벡터(

)로 산출할 수 있다. 그리고, 전력 제어기(525)는, 산출된 보상 전압 지령치의 벡터(

)를 제2 전압 지령치의 벡터(

)로 출력할 수 있다.That is, the power controller 525 calculates the vector of the output current flowing through the motor

), And the vector of the final voltage command value (

) Is a vector of the first voltage command value (

), Which is the closest vector to the vector of the compensation voltage command value

). Then, the power controller 525 calculates the vector of the calculated compensation voltage command value (

) To the vector of the second voltage command value (

).

The inverter output voltage vector, that is, the third voltage command value V ^* 3 can be finally calculated by the sum of the first voltage command value V ^* ₁ and the second voltage command value V ^* ₂ .

Thus, according to the embodiment of the present invention, real-time compensation of the output voltage becomes possible for desired inverter output power control. In other words, real-time compensation according to the load becomes possible. Therefore, when the inverter is driven under the capacitorless operation, the system current becomes close to the sinusoidal wave and the harmonic component is considerably reduced. Therefore, the harmonic regulation is satisfied.

10A illustrates the waveform of the dc voltage and the grid current according to the first mode.

The grid current shaping is performed according to the operation of the first mode operation unit 420 of Fig. 8A, so that the grid current shaping is performed corresponding to the dc short voltage waveform Vdc_mode1 as shown in the figure, ) Waveform is formed. As a result, the harmonics are reduced and the harmonic regulation is satisfied.

FIG. 10B illustrates waveforms of the dc voltage and the grid current according to the second mode.

According to the operation of the second mode operation unit 430 of Fig. 8B, the grid current shaping is not performed as described above, and therefore, the grid current Ia, which does not follow the dc short voltage waveform Vdc_mode2, (Ig_mode2) waveform is formed. However, since the motor output is less than a predetermined value, the harmonics of the system current are not so large, and instead, the output of the motor is improved.

The motor driving apparatus and the air conditioner having the same according to the present invention are not limited to the configuration and the method of the embodiments described above, but the embodiments can be applied to all of the embodiments Or some of them may be selectively combined.

Meanwhile, the method of operating the motor driving apparatus or the air conditioner of the present invention can be implemented as a processor-readable code on a recording medium readable by a processor included in the motor driving apparatus or the air conditioner. The processor-readable recording medium includes all kinds of recording apparatuses in which data that can be read by the processor is stored. Examples of the recording medium that can be read by the processor include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave such as transmission over the Internet . In addition, the processor-readable recording medium may be distributed over network-connected computer systems so that code readable by the processor in a distributed fashion can be stored and executed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

Claims (13)

An inverter having a plurality of switching elements, for converting pulsating pulsating power and outputting the converted DC power to the motor; And
And a control unit for controlling the inverter,
Wherein,
And controls to operate in a first mode for performing grid current shaping or a second mode for not performing grid current shaping based on the speed and torque of the motor. The method according to claim 1,
Wherein,
Wherein the controller controls the first mode to be performed when the motor output based on the speed and torque of the motor is greater than or equal to a predetermined value and controls the second mode to be performed when the motor output is less than the predetermined value. The method according to claim 1,
And a rectifying unit for rectifying the grid current,
Wherein,
And performs the grid current shaping such that the grid current corresponds to the ripple voltage in the first mode of operation. The method according to claim 1,
Wherein,
And a mode selection unit for selecting either the first mode or the second mode based on a speed calculated based on an output current flowing through the motor and a torque command value. 5. The method of claim 4,
Wherein,
Further comprising a torque command generator for generating the torque command value based on the calculated speed and speed command value. 5. The method of claim 4,
Wherein,
Further comprising a first mode operation unit for operating the motor in a first mode,
Wherein the first mode operation unit comprises:
A current command generator for generating a current command value based on the torque command value;
A voltage command generator for generating a first voltage command value based on the current command value;
A power command generation unit for generating a power command value based on the torque command value;
A power controller for generating a second voltage command value based on the power command value; And
And a switching control signal output unit for outputting a switching control signal based on the first and second voltage instruction values. 5. The method of claim 4,
Wherein,
And a second mode operation unit for operating the motor in a second mode,
Wherein the second mode operation unit comprises:
A current command generator for generating a current command value based on the torque command value;
A voltage command generator for generating a voltage command value based on the current command value; And
And a switching control signal output unit for outputting a switching control signal based on the voltage command value. The method according to claim 1,
Wherein the efficiency of the motor in the second mode section is greater than the efficiency of the motor in the first mode section. A compressor for compressing the refrigerant;
A heat exchanger for performing heat exchange using the compressed refrigerant; And
And a compressor motor drive device for driving a motor in the compressor,
The compressor motor drive apparatus includes:
An inverter having a plurality of switching elements, for converting pulsating pulsating power and outputting the converted DC power to the motor; And
And a control unit for controlling the inverter,
Wherein,
And controls to operate in a first mode for performing grid current shaping or a second mode for not performing grid current shaping based on the speed and torque of the motor. 10. The method of claim 9,
Wherein,
Wherein the controller controls the first mode to be performed when the motor output based on the speed and torque of the motor is greater than or equal to a predetermined value and controls the second mode to be performed when the motor output is less than the predetermined value. 10. The method of claim 9,
And a rectifying unit for rectifying the grid current,
Wherein,
Wherein in the first mode of operation, the grid current shaping is performed such that the grid current corresponds to the ripple voltage. 10. The method of claim 9,
Wherein,
A mode selecting unit that selects either the first mode or the second mode based on a speed calculated based on an output current flowing to the motor and a torque command value;
A torque command generator for generating the torque command value based on the calculated speed and speed command value;
A first mode operation unit for operating the motor in a first mode; And
And a second mode operation unit for operating the motor in a second mode. 13. The method of claim 12,
Wherein the first mode operation unit comprises:
A current command generator for generating a current command value based on the torque command value;
A voltage command generator for generating a first voltage command value based on the current command value;
A power command generation unit for generating a power command value based on the torque command value;
A power controller for generating a second voltage command value based on the power command value; And
And a switching control signal output unit for outputting a switching control signal based on the first and second voltage instruction values.

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