CN108809202A - It is a kind of that there is belt speed to throw the alternating current generator of function again for electric installation - Google Patents

Abstract

The invention relates to the field of AC motor control, in particular to an AC motor power supply device with the function of reintroduction with speed. It realizes the normal power supply of the AC motor and the function of belt speed re-starting, so as to meet the requirements and needs of the control effect of the AC motor under different working conditions. Including controller, rectifier device, filter device, fully controlled device with freewheeling capability, stator voltage or back EMF sampler, carrier generator, working modulation wave generator, analog modulation wave generator, modulator, pre-filter Phase-locking and voltage standardization module, AC motor sector calculation module, AC motor stator residual voltage or back EMF calculator, using the synergy between the working modulation wave generator and the analog modulation wave generator and the AC motor sector calculation module, to realize AC Motor starting, speed regulation, stable operation and low impact current with speed re-start function.

Description

A kind of AC motor power supply device with speed re-introduction function

technical field

The invention relates to the field of AC motor control, in particular to an AC motor power supply device with the function of reintroduction with speed.

Background technique

With the development of electromagnetic field theory, AC motor theory and power electronics technology, the types of AC motors and their control systems are constantly enriched and developed. Due to its good operating characteristics, AC motors are widely used in aerospace, national defense technology, industrial production, transportation and daily life. In practical engineering, in order to meet the needs of speed regulation, general-purpose inverters are often used as power supply devices for AC motors. The frequency and amplitude of the power output by the inverter and the structure of the AC motor itself determine the speed of the AC motor. Due to the needs of the production process, the needs of the work process, or the intermittent failure of the power supply, the AC motor will switch between the power-on state and the power-off state. Usually, the process of reconnecting the power supply when the AC motor is powered off and decelerated and the speed has not decayed to zero is called It is called speed re-rolling. Due to the existence of stator residual voltage (also known as "power-off residual voltage") or back electromotive force, if it is re-injected directly at high speed, a large inrush current and inrush torque will be generated in the line, which will affect the insulation and protection of various devices in the line. The safety of personal equipment will cause harm; if the AC motor is decelerated to a static state and then re-connected to the power supply, it cannot meet the requirements of large inertia applications or applications requiring short downtime.

A Chinese patent disclosed a "frequency converter with speed tracking function and its speed tracking method" in 2014 (patent number CN103580453A). This invention samples the stator residual voltage after power failure, and performs amplification adjustment and shaping And isolated output, the controller calculates the frequency of the pulse signal and then calculates the speed of the motor. This invention can only track the speed of the motor, and does not have the function of re-introduction with speed; a Chinese patent disclosed a "permanent magnet synchronous" in 2015 Control method, device and system for re-introduction of motor with speed" (Patent No. CN103516281A), this invention compares the back EMF with the voltage on the inverter side, if the back EMF of the permanent magnet synchronous motor is higher than the voltage on the inverter side , then the permanent magnet synchronous motor is not allowed to re-start with speed, otherwise the permanent-magnet synchronous motor is allowed to re-start with speed. Inrush current and inrush torque. A Chinese patent disclosed a "Large inertia load permanent magnet synchronous motor drive power-off-restart control method and device" (patent No. CN102684583A) in 2015. This invention uses the permanent magnet synchronous motor after power failure as a generator, and The three-phase AC power output by the motor is fed back to the DC side through the three-phase full-bridge inverter circuit of the freewheeling device, so that the voltage on the DC bus capacitor is maintained at the rated value, and the DC re-investment is performed when the power supply is restored, weakening or avoiding power failure The electrical and mechanical impact brought by the re-inverting process, the invention uses the matching of the amplitude of the DC power supply and the amplitude of the rectified DC residual voltage as the re-introduction condition, and does not take into account the phase angle matching between the stator residual voltage and the voltage after the inverter is also to ensure The key to successful rerolling with speed. At the same time, in the case of frequency conversion control, the above method ignores that the frequency converter is a device that provides power to the motor, and reasonable control of the frequency converter output is the key to re-starting with speed.

Contents of the invention

The present invention aims at the defects existing in the prior art, and aims at the above-mentioned problems existing in the existing AC motor speed reintroduction method, device and system and the industry status quo. The purpose of the present invention is to provide an AC motor with The motor power supply device (hereinafter also referred to as "power supply device") realizes the normal power supply of the AC motor and the function of re-initiating the belt speed, so as to meet the requirements and needs of the control effect of the AC motor under different working conditions.

In order to achieve the above object, the present invention adopts the following technical solutions, including a controller, a rectifier device, a filter device, a fully controlled device with freewheeling capability, a stator voltage or back EMF sampler, a carrier generator, a working modulation wave generator, Analog modulation wave generator, modulator, pre-filter phase-locking and voltage standardization module (voltage standardization circuit), AC motor sector calculation module, AC motor stator residual voltage or back EMF calculator, using the working modulation wave generator and analog The synergistic effect of the modulation wave generator and the AC motor sector calculation module realizes the functions of AC motor starting, speed regulation, stable operation and low impact current with speed re-injection.

As a preferred solution, use the AC motor voltage collector or back EMF calculator, AC motor stator residual voltage or back EMF sampler, pre-filter phase-locked and voltage standardization module, and AC motor sector calculation module to calculate the AC motor stator residual voltage. pressure or back EMF (the value of i is equal to the number of phases of the AC motor), the stator residual voltage or back electromotive force of each phase is sampled and output as At the same time, pre-filter phase-locking and voltage standardization are carried out, and the output of each phase after standardization is use The combination of can uniquely determine the sector Q _i where the rotating part of the AC motor is located (the value of i is related to the number of phases and pole pairs of the AC motor). The controller controls the amplitude A and frequency f of the modulating wave (A=F(f), where F represents a certain functional relationship), and at the same time, according to the calculation results of the sector, the modulating wave and the carrier phase are modulated to generate a pulse signal. The pulse signal control has a continuous The conductor of the fully-controlled device with current capability is turned off, so that the power supply device outputs AC power to the outside.

As another preferred solution, a working modulating wave generator and an analog modulating wave generator are arranged inside the power supply device, and function generating devices, circuits and modules are arranged inside the generator, and the working modulating wave generator and the analog modulating wave generator are controlled Under the action of the AC motor, the process of AC motor starting, speed regulation, stable operation and low impact current re-injection is completed according to the instructions input by the user; for the three-phase two-pole AC motor, the six space sectors I-VI can be controlled by The combination of values Q _i (i=I, II, III, IV, V, VI) is uniquely determined: Q _I = (+1, -1, +1), Q _II = (+1, -1, -1 ), Q _III = (+1, +1, -1), Q _IV = (-1, +1, -1), Q _V = (-1, +1, +1), Q _VI = (-1 , -1, +1), assuming that within a certain sampling interval, the controller of the power supply device detects that Q _II changes to Q _III , indicating that the stator residual voltage or back EMF signal of the B-phase equivalent winding of the AC motor It is exactly at the zero-crossing moment from the negative half cycle to the positive half cycle. At this time, the controller will control the initial value of the B-phase analog modulation wave in the analog modulation wave generator to be zero and the cycle is consistent with the cycle of the stator residual voltage or back EMF. The A-phase analog The period of the modulation wave and the C-phase analog modulation wave is consistent with the B-phase analog modulation wave, and the initial phase angle of the A-phase analog modulation wave and the C-phase analog modulation wave is determined by the spatial position of the three-phase stator equivalent winding of the AC motor and the actual control strategy. It is decided that the three-phase analog modulation wave will exit the operation after several cycles of access to the circuit. The angle is consistent with the initial phase angle of the three-phase analog modulation wave, and the frequency and amplitude of the working modulation wave are determined by the user's command.

Preferably, the analog modulating wave generator and the working modulating wave generator contain function waveform generating devices, which cooperate to complete the functions of AC motor starting, speed regulation, stable operation and belt speed re-introduction.

Preferably, the pre-filter phase-locked and voltage standardization circuit includes a phase-locked loop, an operational amplifier and a high-precision voltage zero-crossing comparator.

More specifically: a controller for users to input instructions, the controller controls the working modulation wave generator to connect to the internal circuit of the power supply device and output a working modulation wave with adjustable frequency and amplitude, and the working modulation wave is modulated with the carrier wave to generate Working pulse, the working pulse controls the on and off of the fully controlled device, the AC power supply with adjustable output frequency and fundamental wave amplitude of the power supply device, and realizes the starting, speed regulation and stable operation of the AC motor; due to the needs of the production process, If the work flow requires or the power supply is intermittently faulty, the power supply for the power supply device will be temporarily disconnected. When the AC motor is powered off and needs to be restarted at high speed, the stator residual voltage or back EMF output by the AC motor will be passed through the sampling circuit and pre-filtered. circuit, phase-locking circuit and voltage standardization circuit are processed into digital signals, and the controller controls the analog modulation wave generator to output an analog modulation wave consistent with the frequency of the input signal according to the input digital signal. After the command is input, the controller controls the analog modulation wave generator to connect to the internal circuit of the power supply device to keep the output frequency and amplitude of the analog modulation wave unchanged. The on and off of the type device, the AC power supply with constant output frequency and constant amplitude of the fundamental wave of the power supply device, the speed of the AC motor will maintain the current speed unchanged, and the analog modulation wave generator will Exit the internal circuit of the power supply device, and at the same time, the working modulation wave generator is connected to the internal circuit of the power supply device. The controller controls the working modulation wave generator to output a working modulation wave whose frequency and amplitude gradually increase according to the constraint conditions. The working modulation wave is modulated with the carrier wave The working pulse is generated, and the working pulse controls the turn-on and turn-off of the full-control device, and the output frequency and fundamental wave amplitude of the power supply device gradually increase according to the constraint conditions. The AC power supply completes the low-impact belt-speed re-injection process of the AC motor.

Compared with the prior art, the present invention has beneficial effects.

The invention provides an AC motor power supply device with the function of re-introduction with speed. The power supply device can realize the starting, speed regulation, stable operation and With the function of re-introduction with speed, the impact current and impact torque are reduced during re-initiation with speed, and the harm caused by the re-initiation impact to the insulation of various devices in the line and the safety of personal equipment is reduced, and it can meet the needs of large inertia AC motors or work requiring short downtime Require.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following expressions.

Fig. 1 is an internal structure diagram of an AC motor power supply device with a speed re-introduction function according to the present invention.

Fig. 2 is a schematic diagram of the three-phase value network and the space voltage vector when the three-phase AC motor of the present invention is re-commissioned at speed.

Fig. 3 is a schematic diagram of a space sector of a three-phase two-pole AC motor according to the present invention.

Fig. 4 is a specific embodiment of an AC motor power supply device with a speed re-introduction function in an AC motor according to the present invention.

In the figure, 1 is the rectification and inverter circuit, 2 is the switch from mains to user side, 3 is the rectification device, 4 is the filter device, 5 is the full-control device with freewheeling capability, and 6 is two devices with freewheeling capability. 7 is the inverter circuit composed of all the bridge arms, 8 is the control circuit of the power supply device, 9 is the switching switch between the working modulation wave and the analog modulation wave, 10 is the equivalent winding of the AC motor stator, 11 is the direction of rotation of the AC motor, 12 is an AC motor power supply device with speed re-throw function, 13 is a wire, 14 is a voltage collector or a back EMF calculator, 15 is a three-phase AC motor, and 16 is a signal line.

Detailed ways

As shown in Figure 1, the present invention includes a rectification and inverter circuit 1, a mains to user side switch 2, a rectification device 3, a filter device 4, a fully-controlled device 5 with freewheeling capability, and two The bridge arm 6 composed of fully controlled devices (the number of bridge arms is determined by the phase number of the AC motor to be powered), the inverter circuit 7 composed of all bridge arms, the control circuit 8 of the power supply device, the switching between the working modulation wave and the analog modulation wave Switch 9 and other necessary components and connecting wires.

Figure 2 is a schematic diagram of the three-phase value network and the space voltage vector when the three-phase AC motor is re-introduced at speed. Reactance, S is the three-phase re-throw switch, Xa, Xb, Xc are the equivalent reactance of the AC motor, u _a , u _b , u _c are the equivalent voltage sources of the three-phase residual voltage (or back EMF); △u _a , △ u _b , △u _c are the vector differences between the three-phase reintroduction power supply and the three-phase residual voltage (or counter electromotive force) equivalent voltage source, δ _a , δ _b , and δ _c are the three-phase reinjection power supply and the three-phase residual voltage ( or back EMF) phase angle difference of the equivalent voltage source, it can be seen that the size of δ _a , δ _b , δ _c and the size of the vector difference determine the magnitude of the current in the network during re-throwing.

When the mains supply is normal, the mains-to-user switch 2 is in the ON state, and the mains will provide power for the control circuit of the power supply device and the rectification and inverter circuit 1 through the mains-to-user switch 2, wherein the mains is passed through the rectifier 3 will be rectified into a fluctuating direct current, and the fluctuating direct current is converted into a constant amplitude direct current by the filter device 4, and the constant amplitude direct current will provide inverter power for the inverter circuit 7 composed of all bridge arms. When the user issues instructions for starting, speed regulation, and stable operation, the controller in the control loop 8 of the power supply device receives the user instruction, controls the carrier wave generator and the working modulation wave generator to output the carrier wave and the modulation wave, and simultaneously controls the work modulation wave and the analog modulation wave The upper side of the wave switching switch 9 is turned on, and the carrier wave and the working modulation wave are phase-modulated by the modulator to generate a working pulse, which controls the on and off of the fully-controlled device 5 with freewheeling capability, the output frequency of the power supply device, the base The AC power supply whose amplitude can be adjusted according to the command realizes the functions of starting, speed regulation and stable operation of the AC motor.

When the production process needs, the work flow needs or the mains power intermittently fails, the mains to user side switch 2 will be in the off state, at this time the power output of the AC motor power supply device with the function of re-introduction with speed will be 0, the AC motor It is in a state of power-off rotation due to no power supply. When the mains power returns to normal, the switch 2 from the mains to the user side is in the conduction state, and the power output of the power supply device remains at 0 before the controller receives the command of reintroduction with speed from the user. At this time, the stator residual voltage of the AC motor Or the back EMF sampler will test the AC motor stator residual voltage or back EMF (the number of i is equal to the number of phases of the stator windings of the AC motor) for sampling, according to Shannon’s sampling law in the control principle, the sampling period is T, the sampling frequency f _s =1/T, and the sampling angular frequency ω _s =2πf _s , the output signal after the AC motor stator residual voltage or back EMF sampler is in Input to the pre-filter phase-locking and voltage standardization module, the pre-filter phase-locking can eliminate noise or unknown harmonics in the signal, the pre-filter can be composed of a voltage holder or a digital filter, the digital filter adopts a bandwidth filtering method, and the bandwidth The maximum value of the angular frequency is ω _r , and ω _r is the rotational speed of the AC motor in the last sampling period. Phase-locking can be achieved by using a phase-locked loop or a PLL (Phase-Locked Loop), or specific harmonics can be used to eliminate the lock Phase method SHE-PLL (Specific Harmonic Eliminate-PLL) and device implementation, voltage standardization can standardize the signal output by the pre-filter phase-locked, the basic method is: if the input signal Then the output signal after voltage normalization If the input signal Then the output signal after voltage normalization The AC motor sector calculation module calculates the input signal The sector position of the rotating part of the AC motor can be determined at this time, and the position detection of the rotating part of the AC motor can be realized. At the same time, the sector calculation module of the AC motor can also calculate the input signal period T _i . The AC motor sector calculation module inputs the calculated sector position and the period of the input signal to the controller, and the controller controls the output of the analog modulation wave generator and the input signal An analog modulation wave with the same frequency, the frequency value is 1/T _i . When the user issues a re-instruction with speed and the controller detects that the sector signal changes, it controls the lower side of the working modulation wave and analog modulation wave switching switch 9 to conduct, and the analog modulation wave generator is connected to the internal circuit of the power supply device. The analog modulation wave with constant output frequency and amplitude, the analog modulation wave and the carrier wave generated by the carrier generator are modulated by the modulator to generate an analog pulse, the analog pulse controls the on and off of the fully controlled device, and the output frequency of the power supply device is constant ( AC power supply with frequency value f ₀ ) and constant fundamental wave amplitude (fundamental wave amplitude value A ₀ ), combined with Figure 2, it can be seen that the reinvestment current in the network is small at this time, and the speed of the AC motor will maintain the current speed No change, after the analog modulation wave has experienced several cycles, the controller controls the upper side of the switching switch 9 for the working modulation wave and the analog modulation wave to conduct, the analog modulation wave generator exits the internal circuit of the power supply device, and the working modulation wave generator is put back into the power supply device Internal circuit, the working modulating wave generator takes f ₀ and A ₀ as the initial value, and the output frequency and amplitude gradually increase to the rated frequency and amplitude working modulating wave according to the constraints, and the working modulating wave and carrier phase modulation generate working pulse , the working pulse controls the turn-on and turn-off of the fully-controlled device 5 with freewheeling capability, and the output frequency and fundamental wave amplitude of the power supply device are gradually increased to the rated frequency and amplitude of the AC power supply according to the constraints, so as to realize the AC motor with Quick reload function.

The calculation principle and process of the AC motor sector are further described in detail in conjunction with accompanying drawing 3, which is a schematic diagram of a three-phase two-pole AC motor space sector, including an AC motor stator equivalent winding 10 and an AC motor rotation direction 11. For an AC motor with m phases and n poles, it can be divided into m×n sectors. Among them, A, B, and C represent the equivalent spatial axes of the stator windings of the three-phase two-pole AC motor, and the spatial angles of the stator windings at 0°, 60°, 120°, 180°, 240°, and 300°, respectively, in the interval (0°, 60° °) means sector I, interval (60°, 120°) means sector II, interval (120°, 180°) means sector III, interval (180°, 240°) means sector IV, interval (240° , 300°) means sector V, and the interval (300°, 0°) means sector VI. When the AC motor rotates, the magnetic field of the rotating part and the magnetic field of the stator winding together constitute the space air gap magnetic field of the AC motor. The space air gap magnetic field can be equivalent to the equivalent magnetic pole, and the pole pair number p _M of the equivalent magnetic pole is the same as the pole of the AC motor The logarithms of p are equal, and p=n/2. The equivalent magnetic poles rotate in space and induce induced potentials on the stator windings of the AC motor. The amplitude and frequency of the induced potentials are proportional to the magnetic field strength and rotation speed of the equivalent magnetic poles. Since the equivalent spatial axis A, axis B, and axis C of the stator winding of the AC motor are the equivalent performance of the stator winding of the AC motor after centralized processing, the spatial position of the axis also determines the space vector of the induced potential on the stator side when the equivalent magnetic pole rotates relation. For a three-phase two-pole AC motor, the induced potentials on the three axes can be expressed as in and It can be directly measured, or indirectly calculated by methods such as the back EMF open-loop integration method and the observer method, which are widely used in existing research. easy to know lag electrical degrees (two sectors), lag Electrical degrees (four sectors). Using the phase-locking and voltage standardization method of the pre-filter of the AC motor described above, the Pre-filtering, phase-locking and normalization are performed, and the normalized signals are respectively expressed as The basic methods of standardized processing are: ①If So if So ②If So if So ③If So if So In order to more intuitively show the change process of the equivalent magnetic pole rotation for one revolution in Figure 3, three concentric rings with alternating colors are introduced in Figure 3 and two color legends are used to represent +1 and -1 respectively, and three concentric circles From the outside to the inside of the ring are and Obviously, the six space sectors I—VI of the three-phase two-pole AC motor can be obtained by The combination of values is uniquely determined, and the combined value of sectors I-VI is expressed as Q _i (i=I, II, III, IV, V, VI), that is, Q _I =(+1,-1,+1), Q _II = (+1, -1, -1), Q _III = (+1, +1, -1), Q _IV = (-1, +1, -1), Q _V = (-1, + 1, +1), Q _VI = (-1, -1, +1). The AC motor sector can easily calculate the value of Q _i at any time, judge the sector where the rotating part of the AC motor is located through the internal table, and calculate the input signal by calculating the duration of a certain sector T _i of the period, and then input the sector position and the period of the input signal to the controller to realize the next step of control.

Shown in accompanying drawing 4, it is a kind of embodiment of the AC motor power supply device with speed reinvestment function in the AC motor of the present invention, by a kind of AC motor power supply device 12, lead wire 13, voltage Necessary connection mechanisms such as a collector or a back EMF calculator 14, a three-phase AC motor 15, and a signal line 16 are formed. When the mains supply is normal, the user inputs a starting command through the control panel or the remote control panel, the controller inside the power supply device 12 controls the working modulation wave generator to connect to the internal circuit of the power supply device 12, and the working modulation wave generator generates and outputs a fixed The frequency is f ₁ and the fixed amplitude is A ₁ three-phase working modulation wave, where the relationship between f ₁ and A ₁ is set by the user, the three-phase working modulation wave and the carrier are modulated by the modulator to generate a working pulse, and the working pulse controls all The full-control device 5 with freewheeling capability in the inverter circuit 7 composed of bridge arms is turned on and off, the power supply device 12 outputs a three-phase AC power supply with _a fixed frequency of f1, and the three-phase AC motor 15 completes the starting process ; The user inputs a speed regulation command through the control panel or a remote control panel, and at this time, the controller inside the power supply device ₁₂ determines the constraint condition _{A 2 =} F( f ₂ ), where F represents a certain functional relationship, then control the working modulating wave generator to connect to the circuit, generate and output the three-phase working modulating wave with frequency f ₂ and amplitude A ₂ , the three-phase working modulating wave and the carrier After being modulated by the modulator, a working pulse is generated, and the working pulse controls the on and off of the fully-controlled device with freewheeling capability in the inverter circuit 7 composed of all the bridge arms. The output frequency of the power supply device 12 is f _o2 and the amplitude is the three-phase AC power supply of A _o2 , where A _o2 = F(f _o2 ), the three-phase AC motor 15 completes the speed regulation process; the user inputs a stable operation command through the control panel or remote control panel, and the controller inside the power supply device 12 controls The working modulating wave generator is connected to the circuit and generates a three-phase working modulating wave with a fixed frequency of f ₃ and a fixed amplitude of A ₃ , the three-phase working modulating wave and the carrier wave are modulated by the modulator to generate working pulses, and the working pulses control all bridges In the inverter circuit 7 composed of arms, the full-control device 5 with freewheeling capability is turned on and off, the power supply device 12 outputs a three-phase AC power supply with a fixed frequency and a fixed fundamental wave amplitude, and the three-phase AC motor 15 completes Stable running process.

When due to the needs of the production process, the needs of the work process or the intermittent failure of the mains, the frequency and amplitude of the output power of the power supply device 12 are 0, and the three-phase AC motor 15 is in a power-off state; Before the speed re-introduction command, the output power frequency and amplitude of the power supply device 12 are still 0. At this time, the voltage collector or back EMF calculator 14 can calculate the stator residual voltage or back EMF of the AC motor, and the calculation result is passed through the signal Line 16 is input to the power supply device 12. The AC motor stator residual voltage or back EMF sampler, the pre-filter phase-locked & voltage standardization module, and the AC motor sector calculation module in the power supply device 12 perform the stator residual voltage or back EMF according to the above The process is processed, and the processing result is input to the controller of the power supply device 12, and the controller controls the analog modulation wave generator to generate a three-phase analog modulation wave consistent with the frequency of the input signal, the frequency of which is f _i , and the amplitude is A _i , and A _i =F(f _i ); when the user inputs the belt speed re-start command through the control panel or the remote control panel, the controller in the power supply device 12 detects that the sector signal changes, that is, the change from Q _i to Q _i When ₊₁ , the controller controls the analog modulation wave generator to be connected to the internal circuit of the power supply device 12, and outputs a three-phase analog modulation wave with a fixed frequency of f _i and a fixed amplitude of A _i , and the analog modulation wave and carrier wave are modulated by the modulator Generate analog pulses, the analog pulses control the on and off of the fully controlled device, and the power supply device outputs a three-phase AC power supply with a fixed frequency f _oi and a fixed fundamental wave amplitude A _oi , where A _oi = F(f _oi ) , at this time the speed of the three-phase AC motor will remain unchanged at the current speed, and the controller of the power supply device 12 controls the analog modulation wave generator to exit the internal circuit of the power supply device after the analog modulation wave has experienced several cycles. It can be set by the user through the control panel or remote control panel; at the same time, the working modulating wave generator is connected to the internal circuit of the power supply device, and the controller controls the working modulating wave generator to generate and output a three-phase working modulating frequency of f ₄ and amplitude of A ₄ wave, A ₄ and f ₄ need to meet the condition A ₄ =F(f ₄ ), the working modulation wave and carrier phase modulation generate working pulse, the working pulse controls the on and off of the fully-controlled device, and the output frequency of the power supply device is f _o4 , a three-phase AC power supply whose fundamental amplitude is A _o4 , where A _o4 = F(f _o4 ). Through the above process, the belt speed re-introduction function of the three-phase AC motor 15 is completed. At the same time, the amplitudes A ₁ , A ₂ , A ₃ , A ₄ , A _i , A _o2 , A _o4 , A _oi and frequencies f ₁ , f ₂ , f ₃ , f ₄ , f The actual values of _i , f _o2 , f _o4 , and f _oi can be set by the user through the control panel, remote control panel, or preset program on-site control or program control, and can also be set according to actual production needs. For the three-phase two-pole AC motor, according to the content mentioned above, the six space sectors I-VI can be obtained by The combination of values Q _i (i=I, II, III, IV, V, VI) is uniquely determined: Q _I = (+1, -1, +1), Q _II = (+1, -1, -1 ), Q _III = (+1, +1, -1), Q _IV = (-1, +1, -1), Q _V = (-1, +1, +1), Q _VI = (-1 , -1, +1), assuming that within a certain sampling interval, the controller of the power supply device 12 detects that Q _II changes to Q _III , indicating that the stator residual voltage or back EMF waveform of the B-phase equivalent winding of the AC motor is just in the negative At the zero-crossing moment from the half cycle to the positive half cycle, the controller will control the initial value of the B-phase analog modulation wave in the analog modulation wave generator to be zero and the cycle is consistent with the cycle of the stator residual voltage or back EMF.

In the above-mentioned embodiments, all user instructions can be input into the controller of the AC motor power supply device with speed re-introduction function of the present invention through the control panel, remote control panel or preset program, and the controller can control or Program control completes the starting, speed regulation, stable operation and speed re-injection functions of the AC motor; the number of wires 13 is consistent with the number of phases of the AC motor, and the number of signal wires 16 is determined by the stator residual voltage or back EMF. The calculation method is determined, and the spatial arrangement and shape structure of each component in the above-mentioned embodiments are not limited to the expression form in Fig. 4 .

The AC motors in the above embodiments are three-phase two-pole AC motors, but they are also applicable to multi-phase and multi-pole situations.

The above is only an embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention, such as the communication in this embodiment The inner rotor structure of the motor is changed to the outer rotor structure or changed to a disc structure or changed to a linear structure, or the improvement of the general power supply frequency converter, or a single modulation wave generator is used to realize the working modulation wave generator and analog modulation wave generation device, or use rotary encoders, position and speed sensors, etc. to indirectly determine the sector involved in the present invention by means of obtaining the position signal of the rotating part of the AC motor, as well as multi-phase multi-pole AC motors, all should be included in the protection scope of the present invention within.

It should also be noted that, in this article, terms such as the schematic diagram of the embodiment or the schematic diagram of the AC motor space sector, input and output, front and rear, turn-on and turn-off, access and exit are only used to indicate that a An entity or operation is distinguished from another entity or operation without necessarily requiring or implying any such actual relationship or order between the entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "consisting of" does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on and explains the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

Claims (4)

1. An AC motor power supply device with speed re-throw function, characterized in that it includes a controller, a rectifier, a filter, a fully controlled device with freewheeling capability, a stator voltage or back EMF sampler, and a carrier generation generator, working modulating wave generator, analog modulating wave generator, modulator, pre-filter phase-locking and voltage standardization module, AC motor sector calculation module, AC motor stator residual voltage or back EMF calculator, using working modulating wave to generate The synergistic effect of the generator and the analog modulation wave generator and the AC motor sector calculation module realize the functions of AC motor starting, speed regulation, stable operation and low impact current with speed re-injection. 2. A kind of AC motor power supply device with speed re-investment function according to claim 1, characterized in that: using AC motor voltage collector or back EMF calculator, AC motor stator residual voltage or back EMF sampler, Pre-filter phase-locking and voltage standardization module, AC motor sector calculation module to calculate AC motor stator residual voltage or back EMF (the value of i is equal to the number of phases of the AC motor), the stator residual voltage or back electromotive force of each phase is sampled and output as At the same time, pre-filter phase-locking and voltage standardization are carried out, and the output of each phase after standardization is use The combination of can uniquely determine the sector Q _i where the rotating part of the AC motor is located (the value of i is related to the number of phases and pole pairs of the AC motor). The controller controls the amplitude A and frequency f of the modulating wave (A=F(f), where F represents a certain functional relationship), and at the same time, according to the calculation results of the sector, the modulating wave and the carrier phase are modulated to generate a pulse signal. The pulse signal control has a continuous The conductor of the fully-controlled device with current capability is turned off, so that the power supply device outputs AC power to the outside. 3. A kind of AC motor power supply device with speed re-throw function according to claim 1, characterized in that: the power supply device is internally provided with a working modulating wave generator and an analog modulating wave generator, and the generator is internally provided with a function Generating devices, circuits and modules, the working modulating wave generator and the analog modulating wave generator, under the action of the controller, complete the process of AC motor starting, speed regulation, stable operation and low-impact current speed re-injection according to the instructions input by the user; For a three-phase two-pole AC motor, the six space sectors I—VI can be given by The combination of values Q _i (i=I, II, III, IV, V, VI) is uniquely determined: Q _I = (+1, -1, +1), Q _II = (+1, -1, -1 ), Q _III = (+1, +1, -1), Q _IV = (-1, +1, -1), Q _V = (-1, +1, +1), Q _VI = (-1 , -1, +1), assuming that within a certain sampling interval, the controller of the power supply device detects that Q _II changes to Q _III , indicating that the stator residual voltage or back EMF signal of the B-phase equivalent winding of the AC motor It is exactly at the zero-crossing moment from the negative half cycle to the positive half cycle. At this time, the controller will control the initial value of the B-phase analog modulation wave in the analog modulation wave generator to be zero and the cycle is consistent with the cycle of the stator residual voltage or back EMF. The A-phase analog The period of the modulation wave and the C-phase analog modulation wave is consistent with the B-phase analog modulation wave, and the initial phase angle of the A-phase analog modulation wave and the C-phase analog modulation wave is determined by the spatial position of the three-phase stator equivalent winding of the AC motor and the actual control strategy. It is decided that the three-phase analog modulation wave will exit the operation after several cycles of access to the circuit. The angle is consistent with the initial phase angle of the three-phase analog modulation wave, and the frequency and amplitude of the working modulation wave are determined by the user's command. 4. A power supply device for an AC motor with a speed re-throw function according to claim 1, characterized in that: the analog modulating wave generator and the working modulating wave generator contain function waveform generating devices, and cooperate to complete the AC motor starting , speed regulation, stable operation and speed re-throw function.