CN104993494B - Motor simulator based on four-quadrant power electronic converter and method - Google Patents

Abstract

The invention provides a motor simulation device and method based on a four-quadrant power electronic converter. The device includes an input switch, an input transformer, a connecting reactance, a power unit, an output reactance and an output switch. To make the voltage of the power unit tend to be stable, by controlling the voltage and current at the output end of the four-quadrant power electronic converter, the four-quadrant power electronic converter can change the active or reactive power emitted or absorbed, thereby simulating synchronous generators and asynchronous power generators Machine, synchronous motor, asynchronous motor operating characteristics. In the case of generator characteristics, the converter can provide power for the load, and can also provide a test source for the load to detect the load characteristics, and can also adjust the reactive power of the grid, etc.; The assessment power supply provides a load to detect the characteristics of the power supply, and can also be used as a load to adjust the power balance of the power grid, etc., with convenient control and timely response.

Description

A motor simulation device and method based on a four-quadrant power electronic converter

technical field

The invention relates to the technical field of power electronics, in particular to a motor simulation device and method based on a four-quadrant power electronic converter.

Background technique

Motors play a vital role in industrial production and research experiments. Synchronous generators and asynchronous generators can generate active power and inductive and capacitive reactive power, so they can supply power to loads or adjust active and reactive power to the grid. Synchronous motors and asynchronous motors can absorb active power and inductive and capacitive reactive power, so they can be used as loads or to regulate active and reactive power on the grid.

Due to the large inertia, slow response and limited functions of the traditional motor, the control of the motor is more complicated. Therefore, the use of power electronic devices to simulate the characteristics of the motor is favored. The Chinese invention patent with the application number 201410157692.0 discloses "A Microgrid and Microsource Control Method Based on Virtual Synchronous Generator". At the same time, it can also realize the switching of different operating modes of the microgrid, but this method can only simulate the operating characteristics of synchronous generators, which has certain limitations.

Contents of the invention

The purpose of the present invention is to provide a motor simulation device and method based on a four-quadrant power electronic converter, which can not only simulate the characteristics of synchronous generators and asynchronous generators, but also simulate the characteristics of synchronous motors and asynchronous motors.

To achieve the above object, the present invention adopts the following technical solutions:

A motor simulation device based on a four-quadrant power electronic converter, including an input switch, an input transformer, a connection reactance, a power unit, an output reactance, an output switch and a first control system, and the input transformer adopts three single-phase transformers connected in series Structure, the primary side adopts delta connection method, the secondary side adopts multi-secondary winding structure, each secondary winding is connected to the reactance and a single power unit in turn, and the single power units on each secondary winding are connected in cascade form Stand up to form a single-phase power unit, the power unit is composed of three single-phase power units, the output terminals of the three single-phase power units are respectively connected to the power grid or the equipment under test through the output reactance and the output switch, the output of the power unit adopts In the star connection method with a neutral line, the first control system controls the inverter side connected to the power unit, and is used to form a modulation wave to modulate the inverter side of the power unit;

When forming the modulated wave, the first control system first performs PI control on the difference between the reference value and the actual value of the active power on the inverter side of the power unit, and at the same time, the first control system also controls the reactive power on the inverter side of the power unit. The difference between the reference value and the actual value is controlled by PI, and the coordinates of the PI control results of active power and reactive power are transformed to obtain the current reference value on the inverter side of the power unit. The first control system then compares this reference value with the power unit The difference between the actual value of the inverter side current is repeatedly learned and controlled to obtain a voltage modulation signal, and then the first control system adds the output voltage at the output end of the converter and the modulation voltage 90° ahead of the output end voltage to obtain voltage feedforward control signal. Finally, the first control system adds the voltage feedforward control signal to the voltage modulation signal to obtain the modulated wave on the inverter side of the power unit. Adding this modulated wave to the inverter side of the power unit can control the power unit The inverter side of the device is modulated to adjust the phase of the output voltage and output current of the device.

The single power unit on each secondary winding adopts two H-bridge back-to-back connections, the left H-bridge is the rectifier side, the right H-bridge is the inverter side, and the H-bridge uses a fully-controlled semiconductor device, and all of them are connected in parallel with A reverse freewheeling diode, with an energy storage capacitor connected in parallel between the two H bridges.

The individual power units on each of the secondary windings are connected in cascaded form, the number of cascades is determined by the voltage level of the motor to be simulated, and the inverter side of the single power unit of each phase adopts carrier phase-shifted sine controlled by pulse width modulation.

It also includes a second control system. The second control system controls the rectification side connected to the power unit, and is used to form a modulation wave to modulate the rectification side of the power unit. When forming a modulation wave, the second control system first converts the collected energy storage The voltage at both ends of the capacitor is averaged by a sliding window. After obtaining the average value of a period, the difference between the average value and the rated voltage at both ends of the energy storage capacitor is controlled by PI. The second control system then compares the output signal of the PI control with the voltage The voltage of the input transformer secondary winding collected by the transformer is multiplied to obtain the reference value of the input current of the power unit, and then the second control system compares the reference value with the measured value of the input current of the power unit collected by the current transformer Then, the second control system performs P control on the voltage input to the secondary winding of the transformer to obtain a feedforward control signal. Finally, the second control system adds the modulation signal to the feedforward control signal. The modulation wave on the rectification side of the power unit can be obtained, and the modulation wave can be added to the rectification side of the power unit to modulate the rectification side of the power unit, so that the energy storage capacitor has a stable voltage.

A motor simulation method based on a four-quadrant power electronic converter, comprising the following steps in sequence

(1) The input switch is closed first, the input transformer is put into operation, and the energy storage capacitor starts charging;

(2) Select the required voltage U _ref , current I _ref , and phase angle θ _ref to calculate active power reference value P _ref and reactive power reference value Q _ref , where, P _ref = U _ref I _ref cosθ _ref , Q _ref = U _ref I _ref sinθ _ref , the subscript ref represents the grid;

(3) Use the power sensor to collect the active power P and reactive power Q on the inverter side of the power unit, and input the difference between the calculated active power reference value P _ref and the measured active power P on the inverter side of the power unit into the first A PI controller, which inputs the difference between the calculated reactive power reference value Q _ref and the reactive power Q measured on the inverter side of the power unit into the second PI controller, and the active power and After coordinate transformation of the reactive power, the current reference value i ^* on the inverter side of the power unit is obtained; the calculation formula of the first PI controller is The calculation formula of the second PI controller is Among them, k _p3 and k _p4 are proportional coefficients, k _i3 and k _i4 are integral coefficients, the subscript p represents the proportion, and the subscript i represents the integral;

(4) Use the current transformer to collect the actual current value i _s of the inverter side of the power unit, and compare the current reference value i ^* of the inverter side of the power unit obtained in step (3) with the actual current value i _s of the inverter side of the power unit Repeated learning control to obtain the modulation signal V _m1 ;

(5) Use the voltage transformer to collect the output terminal voltage u _s of the device, multiply the voltage u _s by the proportional coefficient k _p5 to obtain the component k _p5 u _s in phase with the output voltage, and multiply the voltage u _s⊥ by the proportional coefficient k _p6 Get the component k _p6 u _s⊥ that is 90° ahead of the output voltage. After k _p5 u _s is added to k _p6 u _s⊥ , the feedforward control signal V _m2 is obtained, and the modulation signal V _m1 is compared with the feedforward control signal V _m2 After adding, the modulation wave V _m on the inverter side of the single power unit is obtained, the voltage u _s⊥ is the voltage 90° ahead of the output terminal voltage of the device, and the subscript p represents the ratio;

(6) The modulated wave V _m of the single power unit inverter side obtained in step (5) is sequentially staggered by 180/N, and N is the number of power units of each phase, so that the modulated wave of each power unit can be obtained;

(7) Add the modulated waves of each power unit obtained in step (6) to the inverter side of the power unit in turn, and control the inverter side of the power unit, thereby adjusting the phase of the output voltage and output power of the device.

Also include step (8) to step (13), specifically:

(8) Use a voltage transformer to collect the voltage at both ends of the energy storage capacitor, denoted as u _dc , average the sliding window to obtain the average value of a cycle The subscript dc means direct current;

(9) The average value obtained in step (8) and the reference value of the voltage across the storage capacitor The difference Δu _dc is input to the third PI controller to obtain the signal ΔI, the reference value The magnitude of is equal to the rated voltage of the energy storage capacitor; the calculation formula of the third PI controller is Among them, k _p is the proportional coefficient, p represents the proportion, k _i is the integral coefficient, i represents the integral, and s represents the Laplace transform;

(10) Use the voltage transformer to collect the voltage u _s1 of the secondary winding of the input transformer, multiply the signal ΔI obtained in step (9) by the voltage u _s1 of the secondary winding of the input transformer, and obtain the reference value of the input current of the power unit The subscript s1 indicates the secondary side of the transformer, and the subscript s indicates the transformer;

(11) Use the current transformer to collect the input current i _s of the power unit, and set the reference value of the input current of the power unit The difference Δi _s from the measured value i _s of the input current of the power unit is input to the first P controller, and multiplied by the proportional coefficient k _p1 to obtain the voltage modulation signal u _m1 , where the subscript p represents the proportion;

(12) Input the collected voltage u _s1 of the secondary winding of the input transformer into the second P controller, multiply it by the proportional coefficient k _p2 , and obtain the voltage feedforward control signal u _m2 , and combine the voltage modulation signal u _m1 with the voltage feedforward The control signal u _m2 is added to obtain the modulated wave u _m on the rectification side of the power unit, where the subscript s1 represents the secondary side of the transformer, the subscript s represents the transformer, and the subscript p represents the ratio;

(13) Apply the modulated wave u _m obtained in step (12) to the rectification side of the power unit, so that the energy storage capacitor has a stable voltage.

The invention can simultaneously simulate the characteristics of synchronous generators, synchronous motors, asynchronous generators and asynchronous motors.

When the current leads the voltage by 0-90°, the converter generates active power and capacitive reactive power; when the current lags the voltage by 0-90°, the converter generates active power and inductive reactive power. Simulate synchronous or asynchronous generator characteristics.

When the current leads the voltage by 90-180°, the converter absorbs active power and inductive reactive power; when the current lags the voltage by 90-180°, the converter absorbs active power and capacitive reactive power. Simulate synchronous or asynchronous motor characteristics.

In the case of generator characteristics, the converter can provide power for the load, and can also provide a test source for the load to detect the load characteristics, and can also adjust the reactive power of the grid, etc.; The assessment power supply provides a load to detect the characteristics of the power supply, and can also be used as a load to adjust the power balance of the power grid. At the same time, the present invention uses a four-quadrant power electronic converter to simulate a motor, which is convenient for control and timely in response.

Description of drawings

Fig. 1 is a topological structure diagram of a motor simulation device based on a four-quadrant power electronic converter according to the present invention;

Fig. 2 is the circuit diagram of the power unit in the device shown in Fig. 1;

Fig. 3 is a schematic diagram of the topology of the single-phase power electronic converter in the device shown in Fig. 1;

Fig. 4 is a block diagram of the modulation wave generation algorithm on the rectification side of the power unit shown in Fig. 2;

Figure 5 is a block diagram of the modulation wave generation algorithm on the inverter side of the power unit when the converter is connected to the grid;

FIG. 6 is a vector diagram of voltage and current at the single-phase output terminal shown in FIG. 3 .

detailed description

As shown in Figures 1 to 3, the motor simulation device based on a four-quadrant power electronic converter according to the present invention includes an input switch 101, an input transformer 102, a connection reactance 103, a power unit 104, an output reactance 105, and an output switch 106 , the first control system and the second control system, the input transformer 102 adopts the structure of three single-phase transformers connected in series, the primary side adopts the delta connection method, the secondary side adopts a multi-secondary winding structure, and each secondary winding is respectively connected to the connecting reactance 103 and a single power unit, the single power units on each secondary winding are connected in cascaded form to form a single-phase power unit, the number of cascading is determined by the voltage level of the system to be simulated, each secondary winding The single power unit is controlled by carrier phase-shifted sine wave pulse width modulation (CPS-SPWM). The power unit 104 is composed of three single-phase power units, and the output terminals of the three single-phase power units are respectively passed through the output reactance 105 and the output switch 106 are connected to the power grid or the equipment under test, and the output end of the power unit 104 adopts a star connection with a neutral line.

The single power unit on each secondary winding adopts two H-bridge back-to-back connections, the left H-bridge is the rectifier side, the right H-bridge is the inverter side, and the energy storage capacitor C is connected in parallel between the two H-bridges. G1, G2, G3, G4, G5, G6, G7, and G8 are IGBTs connected in parallel with reverse freewheeling diodes.

The first control system controls and connects the inverter side of the power unit 104, and is used to form a modulation wave to modulate the inverter side of the power unit 104. When the first control system forms a modulation wave, it first controls the active power PI control is performed on the difference between the reference value and the actual value of the power unit 104. At the same time, the first control system also performs PI control on the difference between the reference value and the actual value of the reactive power on the inverter side of the power unit 104, and the active power and reactive power Coordinate transformation is performed on the PI control result to obtain the current reference value on the inverter side of the power unit 104, and the first control system performs repeated learning control on the difference between the reference value and the actual current value on the inverter side of the power unit 104 to obtain a voltage modulation signal, Then the first control system adds the output voltage at the output terminal of the converter and the modulation voltage 90° ahead of the output terminal voltage to obtain a voltage feedforward control signal. Finally, the first control system combines the voltage feedforward control signal with the voltage modulation Signals are added to obtain the modulation wave on the inverter side of the power 104 unit, and the modulation wave is added to the inverter side of the power unit to modulate the inverter side of the power unit, thereby adjusting the output voltage of the device and then the phase of the output current .

The second control system controls the rectification side connected to the power unit 104 to form a modulation wave to modulate the rectification side of the power unit 104. When forming the modulation wave, the second control system first collects the voltage across the energy storage capacitor C Carry out sliding window averaging, after obtaining the average value of one cycle, then perform PI control on the difference between the average value and the rated voltage at both ends of the energy storage capacitor C, and the second control system will collect the output signal of PI control with the voltage transformer After multiplying the voltage of the secondary winding of the input transformer 102, the reference value of the input current of the power unit 104 is obtained, and then, the second control system compares this reference value with the measured value of the input current of the power unit 104 collected by the current transformer Then, the second control system performs P control on the voltage input to the secondary winding of the transformer 102 to obtain a feedforward control signal, and finally, the second control system adds the modulation signal to the feedforward control signal , the modulation wave on the rectification side of the power unit 104 can be obtained, and the modulation wave can be added to the rectification side of the power unit 104 to modulate the rectification side of the power unit 104 so that the energy storage capacitor C has a stable voltage.

As shown in Fig. 4 and Fig. 5, the motor simulation method based on the four-quadrant power electronic converter of the present invention includes the following steps in sequence:

(1) First close the input switch 101, the input transformer 102 is put into operation, and the energy storage capacitor C starts charging;

(2) Use a voltage transformer to collect the voltage at both ends of the energy storage capacitor C, denoted as u _dc , average the sliding window to obtain the average value of a cycle The subscript dc means direct current;

The voltage u _dc at both ends of the energy storage capacitor actually contains a dc component and an ac component, but the amplitude of the ac component is small and difficult to be controlled, so the control of u _dc is transformed into its dc component The control of the u _dc sliding window is averaged to obtain the average value of a cycle the DC component The sliding-window averaging adopts the sliding-window FFT analysis method, which is a well-known technique and will not be repeated here.

(3) The average value obtained in step (2) and the reference value of the voltage across the energy storage capacitor C The difference Δu _dc is input to the third PI controller to obtain the signal ΔI, the calculation formula of the third PI controller is Among them, k _p is the proportional coefficient, p represents the proportion, k _i is the integral coefficient, i represents the integral, s represents the Laplace transform, and the reference value The magnitude of Δu dc is equal to the rated voltage at both ends of the energy storage capacitor C, which can be obtained by checking the manual, and Δu _dc can be obtained by making a difference through software.

(4) Use a voltage transformer to collect the voltage u _s1 of the secondary winding of the input transformer 102, and multiply the signal ΔI obtained in step (3) by the voltage u _s1 of the secondary winding of the input transformer 102 to obtain a reference value of the input current of the power unit 104 The subscript s1 indicates the secondary side of the input transformer 102, the subscript s indicates the input transformer 102, and the multiplication of ΔI and the secondary winding voltage u _s1 of the input transformer 102 is realized by software.

(5) Utilize the current transformer to collect the input current i _s of the power unit 104, and input the reference value of the power unit 104 current The difference Δi _s from the measured value i _s of the input current of the power unit 104 is input to the first P controller, and multiplied by the proportional coefficient k _p1 to obtain the voltage modulation signal u _m1 , where the subscript p represents the ratio, and the subscript p1 is only Distinguishment is not a variable. The subscripts m, m1 and s only serve as a distinction, not a variable. Δi _s is obtained through software difference.

(6) Input the collected voltage u _s1 of the secondary winding of the input transformer 102 into the second P controller, multiply it by the proportional coefficient k _p2 , obtain the voltage feedforward control signal u _m2 , and modulate the voltage obtained in step (5) The signal u _m1 is added to the voltage feed-forward control signal u _m2 to obtain the modulation wave u _m on the rectification side of the power unit 104, and this modulation wave u _m is added to the rectification side of the power unit 104 to keep the voltage on the energy storage capacitor C Stable, wherein, the subscript s1 indicates the secondary side of the input transformer 102, the subscript s indicates the input transformer 102, the subscripts m and m2 both play a distinguishing role, and are not variables, the subscript p indicates a ratio, and the subscript p2 is only a distinguishing function. is not a variable.

(7) Select the required voltage U _ref , current I _ref , and phase angle θ _ref , and calculate active power reference value P _ref and reactive power reference value Q _ref , where, P _ref = U _ref I _ref cosθ _ref , Q _ref =U _ref I _ref sinθ _ref , the subscript ref represents the grid.

The output side of the device of the present invention is connected to a certain position of the power grid, so the voltage U _ref is determined, and the current I _ref and phase angle θ _ref are determined according to the needs of the user.

(8) Utilize the power sensor to collect the active power P and reactive power Q on the inverter side of the power unit 104, and input the difference between the calculated active power reference value P _ref and the measured active power P on the inverter side of the power unit 104 The first PI controller, the calculation formula of the first PI controller is Input the difference between the calculated reactive power reference value Q _ref and the reactive power Q measured on the inverter side of the power unit into the second PI controller, and the calculation formula of the second PI controller is After the active power and reactive power after PI control are transformed through dq-abc (that is, coordinate transformation), the current reference value i ^* on the inverter side of the power unit is obtained;

k _p3 and k _p4 are proportional coefficients, k _i3 and k _i4 are integral coefficients, subscript p means proportion, subscript i means integral, and subscripts p3, p4, i3, and i4 are only for distinction, not variables; The dq-abc transformation, that is, the coordinate transformation is a well-known technology, and will not be repeated here.

(9) Use a current transformer to collect the current actual value i on the inverter side of the power unit 104, and compare the current reference value i ^* on the inverter side of the power unit 104 obtained in step (8) with the actual current value on the inverter side of the power unit 104 The difference of i is subjected to repeated learning control to obtain the modulated signal V _m1 , and the subscripts m and m1 are only for distinguishing, not variables.

The repeated learning control process is shown in the block diagram in Figure 6. In the figure, k _r is the feedback proportional coefficient. In order to ensure a certain stability margin, k _r is set to 0.8-2 in this embodiment; k _f is the forgetting factor, which is usually less than 1. The value in this embodiment is 0.95; k _s is the repetitive control coefficient. When the values of k _r and k _f are determined, the value of k _s affects the stability of the system. When k _s = 2, the system is in critical stability. Therefore, k _s is 0-2. In this embodiment, k _s is 1-1.5. e- ^sT represents the delay operator of the learning cycle. The repeated learning control process uses the periodicity of the error signal to compensate, so that the cycle of the system The error can be gradually attenuated or eliminated, so that the system output can reach the expected target control strategy. By using repetitive learning control, it is possible to ensure that the static error of compensation is zero while realizing accurate tracking of the command current. In the present invention, the voltage modulation signal V _m1 can reach a desired value by using the above repeated learning control process.

(10) Use the voltage transformer to collect the output terminal voltage u _s of the device. For phase A, it is the voltage between the two points of the output terminal AN in Figure 3. Multiply the output terminal voltage u _s by the proportional coefficient k _p5 to get The component k _p5 u _s with the same phase as the output voltage u _s , the voltage u _s⊥ is multiplied by the proportional coefficient k _p6 to get the component k _p6 u _s⊥ ahead of the output voltage by 90°, the voltage u _s⊥ is ahead of the output of the device The voltage of the terminal voltage at 90° can be obtained by using a phase-shifting transformer. After adding k _p5 u _s and k _p6 u _s⊥ , the feed-forward control signal V _m2 is obtained, and the modulation signal V _m1 obtained in step (9) is combined with the feed-forward The control signal V _m2 is added to obtain the modulated wave V _m on the inverter side of a single power unit, where the subscript p represents the ratio, and the subscripts p5, p6, m, m2, and s are only used to distinguish, not variables.

A single power unit is cascaded, and the modulated wave V _m on the inverter side of the single power unit is staggered by 180/N in turn, where N is the number of power units in each phase, and the modulated wave of each power unit can be obtained.

(11) Apply the modulated wave of each power unit obtained in step (10) to the inverter side of the power unit 104 in sequence, and control the power unit 104 to adjust the phase of the output voltage and output current.

When the present invention is working, the modulated waves obtained in the above steps are respectively added to the rectification side and the inverter side of the power unit, and the amplitude and phase of the output terminal voltage and current are measured respectively, as shown in Figure 6, is the output voltage, is the output current, θ is the output current Leading output voltage angle to the output terminal voltage As a reference vector, when the output current In the first quadrant, that is, when the phase of the current at the output terminal leads the phase of the voltage at the output terminal by 0° to 90°, the converter generates active power and capacitive reactive power; when the current at the output terminal In quadrant IV, that is, when the current phase at the output terminal lags behind the voltage phase at the output terminal by 0° to 90°, the converter generates active power and inductive reactive power. In the above two cases, the converter simulates the synchronous generator and the asynchronous generator characteristic.

When the output current In quadrant II, that is, when the phase of the current at the output terminal leads the phase of the voltage at the output terminal by 90° to 180°, the converter absorbs active power and inductive reactive power; when the current at the output terminal In the third quadrant, that is, when the output current phase lags the output voltage phase by 90~180°, the converter absorbs active power and capacitive reactive power. In the above two cases, the converter simulates the characteristics of synchronous motors and asynchronous motors .

Claims (6)

1. a kind of motor simulation device based on four-quadrant electronic power convertor, it is characterised in that：Including input switch, input Transformator, connection reactance, power cell, output reactance, output switch and the first control system, the input tranformer adopt three Individual single-phase transformer cascaded structure, former limit adopt delta connection, secondary to adopt many vice-side winding structures, and each vice-side winding is equal Reactance and single power cell are sequentially connected, are connected using cascade form between the single power cell on each vice-side winding Come, constitute single-phase power cells, power cell is made up of three single-phase power cells, and the outfan of three single-phase power cells is equal Pass through output reactance respectively and output switch is connected with electrical network or Devices to test, the outfan of power cell is using the star with center line Type connection, the inverter side of the first control system control connection power cell, for forming inverter side of the modulating wave to power cell It is modulated；

First control system when modulating wave is formed, the first reference value and actual value to power cell inverter side active power Difference carry out PI controls, while the first control system is also to the reference value and actual value of power cell inverter side reactive power Difference carries out PI controls, and the PI control results of active power and reactive power are carried out coordinate transform, power cell inversion is obtained The current reference value of side, the first control system is again by the current reference value of power cell inverter side and power cell inverter side electric current The difference of actual value carries out repetitive study control, obtains voltage modulation signal, and then the first control system is by four-quadrant power electronics The output voltage of current transformer outfan and be ahead of 90 ° of output end voltage modulation voltage be added, obtain voltage feedforward control letter Number, finally, this voltage feedforward control signal is added by the first control system with voltage modulation signal, obtains power cell inverter side Modulating wave, this modulating wave is added in into the inverter side of power cell, you can the inverter side of power cell is modulated, so as to adjust The phase place of regulating device output voltage and output current.

2. a kind of motor simulation device based on four-quadrant electronic power convertor as claimed in claim 1, it is characterised in that： Using the back-to-back connected mode of two H bridges, left side H bridges are rectification side to single power cell on described each vice-side winding, right Side H bridges are inverter side, and H bridges adopt all-controlled semiconductor device, and are parallel with reverse fly-wheel diode, between two H bridges simultaneously It is associated with storage capacitor.

3. a kind of motor simulation device based on four-quadrant electronic power convertor as claimed in claim 2, it is characterised in that： Coupled together using cascade form between single power cell on each described vice-side winding, cascade number is electric by simulation is treated The electric pressure of machine determines that the inverter side of the single power cell per phase is carried out using phase-shifting carrier wave Sine Wave Pulse Width Modulation mode Control.

4. a kind of motor simulation device based on four-quadrant electronic power convertor as claimed in claim 3, it is characterised in that： Also include the second control system, the rectification side of the second control system control connection power cell, for modulating wave being formed to power Unit rectification side is modulated, and when modulating wave is formed, the second control system passes through first by the storage capacitor two ends for collecting Voltage carries out sliding window and is averaging, after obtaining the meansigma methodss of a cycle, then by the specified of this meansigma methods and storage capacitor two ends Difference in voltage carries out PI controls, and the output signal that PI is controlled by the second control system again is become with the input that voltage transformer is collected After the voltage of depressor vice-side winding is multiplied, the reference value of power cell input current is obtained, then, the second control system is by power The difference of the measured value of the power cell input current that the reference value of unit input current is collected with current transformer carries out P controls System, obtains modulated signal, then, before the second control system is obtained after the voltage of input tranformer vice-side winding is carried out P controls Feedforward control signal, finally, modulated signal is added by the second control system with feed-forward control signals, you can obtain power cell rectification This modulating wave is added in the rectification side of power cell by the modulating wave of side, you can the rectification side of power cell is modulated, storage is made There can be stable voltage on electric capacity.

5. it is simulated using a kind of motor simulation device based on four-quadrant electronic power convertor described in claim 4 Method, it is characterised in that：Comprise the following steps successively

(1) input switch is first closed, input tranformer is devoted oneself to work, and storage capacitor is started to charge up；

(2) the voltage U needed for selecting_ref, electric current I_ref, phase angle theta_ref, calculate active power reference value P_ref, reactive power reference Value Q_ref, wherein, P_ref=U_refI_refcosθ_ref, Q_ref=U_refI_refsinθ_ref, subscript ref represents reference value；

(3) active-power P and reactive power Q of power cell inverter side are gathered using power sensor, it is active by what is calculated Value and power reference P_refA PI controllers are input into the difference of the active-power P for measuring power cell inverter side, will be calculated Reactive power reference qref Q_refThe 2nd PI controllers are input into the difference of the reactive power Q for measuring power cell inverter side, Active power and reactive power after PI controls obtains the current reference of power cell inverter side after coordinate transform Value i^*；The computing formula of the first PI controllers isThe computing formula of the 2nd PI controllers isWherein, k_p3、 k_p4It is proportionality coefficient, k_i3、k_i4Integral coefficient is, subscript p represents ratio, and subscript i represents integration, and s represents that Laplce becomes Change；

(4) the current actual value i of power cell inverter side is gathered using current transformer_s, the power cell that step (3) is obtained Current reference value i of inverter side^*With the current actual value i of power cell inverter side_sDifference carry out repetitive study control, obtain Modulated signal V_m1；

(5) using voltage transformer harvester output end voltage u_s, by voltage u_sIt is multiplied by proportionality coefficient k_p5After obtain and export electricity Press synchronous component k_p5u_s, voltage u_s⊥It is multiplied by proportionality coefficient k_p6Obtain afterwards being ahead of the component k of 90 ° of output voltage_p6u_s⊥, k_p5u_sWith k_p6u_s⊥After addition, feed-forward control signals V are obtained_m2, by modulated signal V_m1With feed-forward control signals V_m2After addition, obtain The modulating wave V of single power cell inverter side_m, voltage u_s⊥To be ahead of the voltage of 90 ° of device output end voltage, subscript p is represented Ratio；

(6) the modulating wave V of the single power cell inverter side that step (5) is obtained_mStagger 180/N successively, and N is every mutually single work( The number of rate unit, you can obtain the modulating wave of each single-phase power cells；

(7) modulating wave of each single-phase power cells for obtaining step (6) is added in the inverter side of power cell successively, to power The inverter side of unit is controlled, so as to adjusting means output voltage and the phase place of output.

6. a kind of analogy method as claimed in claim 5, it is characterised in that also including step (8) to step (13), specifically For：

(8) voltage at storage capacitor two ends is gathered using voltage transformer, u is designated as_dc, by voltage u_dcSliding window is averaging and obtains one The meansigma methodss in cycleSubscript dc represents direct current；

(9) meansigma methodss that step (8) is obtainedWith the reference value of storage capacitor both end voltageDifference DELTA u_dcInput the Three PI controllers, obtain signal delta I, reference valueSize be equal to storage capacitor rated voltage；The meter of the 3rd PI controllers Calculating formula isWherein, k_pFor proportionality coefficient, p represents ratio, k_iFor integral coefficient, i represents integration, and s represents La Pula This conversion；

(10) the voltage u of input tranformer vice-side winding is gathered using voltage transformer_s1, signal delta I that step (9) is obtained with Input tranformer vice-side winding voltage u_s1The reference value of power cell input current is obtained after multiplicationSubscript s1 indication transformer Secondary；

(11) the input current i of power cell is gathered using current transformer_s, by the reference value of power cell input currentWith The measured value i of power cell input current_sDifference DELTA i_sThe first P controller is input into, proportionality coefficient k is multiplied by_p1Afterwards, obtain voltage Modulated signal u_m1, wherein, subscript p represents ratio；

(12) by the voltage u of the input tranformer vice-side winding for collecting_s1The second P controller is input into, proportionality coefficient k is multiplied by_p2Afterwards, Obtain voltage feedforward control signal u_m2, by voltage modulation signal u_m1With voltage feedforward control signal u_m2It is added, obtains power cell The modulating wave u of rectification side_m, wherein, subscript s1 indication transformer secondary, subscript s indication transformer, subscript p represent ratio；

(13) the modulating wave u that step (12) is obtained_mThe rectification side of power cell is added in, makes that there is on storage capacitor stable electricity Pressure.