A motor simulation method and system based on Quasi-Z source inverter

Abstract

The present invention discloses a motor simulation method and system based on a Quasi-Z source inverter, and relates to the technical field of motor simulation. The method comprises: constructing a mathematical model of a target actual motor and determining the corresponding motor output data; connecting a motor simulator to the output port of a motor driver, and performing pulse width modulation on the motor driver respectively, and performing simulation side inverter control and grid-connected inverter control on the motor simulator; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter is incorporated into a three-phase power grid to simulate the external port characteristics of the target actual motor under different working conditions. The present invention can improve the motor simulation accuracy, anti-interference ability and system power quality, while reducing the test cost.

Description

Technical Field

[0001] The present invention relates to the technical field of motor simulation, and in particular to a motor simulation method and system based on a Quasi-Z source inverter. Background Art

[0002] The motor simulator has high research value and broad application prospects because its test scheme can flexibly and comprehensively test the performance of the motor drive under different working conditions. In some extreme test environments, if the machine fails but is still driven, it may cause damage to the machine and cause safety problems. Therefore, through the motor simulator, the control strategy for the faulty machine can be tested to prevent damage to the actual machine.

[0003] However, existing motor simulation technology usually uses two three-phase power converters connected back-to-back to simulate an actual motor and realize the four-quadrant operation of the motor, that is, the bidirectional flow of electric energy. However, since the upper and lower bridge arms of the power converter cannot be turned on at the same time, this solution needs to consider the dead time, which reduces the system reliability and the power quality in the system. Summary of the invention

[0004] The object of the present invention is to provide a motor simulation method and system based on a Quasi-Z source inverter, which can improve the motor simulation accuracy, anti-interference ability and system power quality, while reducing the test cost.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A motor simulation method based on a Quasi-Z source inverter, comprising:

[0007] Construct a mathematical model of the target actual motor and determine the corresponding motor output data;

[0008] The motor simulator is connected to the output port of the motor driver to form a motor simulation control circuit; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter;

[0009] Based on the motor simulation control circuit, the motor driver is debugged under different working conditions, pulse width modulation is performed on the motor driver, and the motor simulator is controlled by a simulation side inverter and a grid-connected inverter;

[0010] The motor simulator output data measured after debugging is compared with the motor output data. When the comparison result is in the set difference range, the output port of the motor simulator is connected to the three-phase power grid to simulate the external port characteristics of the target actual motor under different working conditions.

[0011] Optionally, constructing a mathematical model of the target actual motor and determining corresponding motor output data specifically includes:

[0012] Establish a mathematical model of the target motor in the abc coordinate system and the dq coordinate system respectively, wherein the mathematical model of the target motor includes a voltage equation and a flux equation describing the electrical characteristics of the motor, a torque equation and a speed equation describing the mechanical characteristics of the motor, and a comprehensive formula of the four equations;

[0013] The motor body parameter acquisition method is used to identify the required parameters and build a table, and the motor output data corresponding to the target actual motor is determined; the motor body parameter acquisition method includes: experimental measurement, least squares method, model reference adaptive method and extended Kalman filter method.

[0014] Optionally, a dual space vector modulation strategy is used for the motor simulator module during the debugging; the dual space vector modulation strategy includes a control strategy for grid voltage orientation and DC link voltage feedforward compensation of the simulation side Quasi-Z source inverter, and a control strategy for fixing the AC side abc axis current of the energy feedback inverter.

[0015] Optionally, the modulation process of the analog side Quasi-Z source inverter is:

[0016] When the analog side Quasi-Z source inverter reference current vector I ref When falling into any sector, the reference current vector I ref The two adjacent valid state vectors I of the sector a and I b , and the zero state vector I z and the through state zero vector I st Synthesis, effective state vector I a and I b Respectively through the duty cycle d α and d β , zero state vector I z By duty cycle d 0r , through state zero vector I st By duty cycle d st , to modulate the six bidirectional switches S of the inverter ap , S bp , S cp , S an , S bn and S cn , and the switching state of a bidirectional switch tube S in the Quasi-Z source network in the Quasi-Z source inverter.

[0017] Optionally, the modulation process of the energy feedback inverter is:

[0018] When the energy feedback inverter reference voltage vector V1 falls into any sector, the reference voltage vector V1 is composed of two adjacent valid state vectors U a and U b , and two zero state vectors U z1 and U z2 Synthesis, effective state vector U a By duty cycle d αμ and d βμ , the effective state vector U b By duty cycle d αv and d βv , zero state vector U z1 By duty cycle d a0i , zero state vector U z2 By duty cycle d 0r and d st , to modulate the six bidirectional switches S of the inverter Ap , S Bp , S Cp , S An , S Bn and S Cn The switch status.

[0019] The present invention also provides a motor simulation system based on a Quasi-Z source inverter, which is applied to the motor simulation method as described above, comprising: a motor drive, a motor simulator and a three-phase power grid connected in sequence; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter.

[0020] Optionally, the Quasi-Z source network in the Quasi-Z source inverter is composed of 2 coupled inductors, 2 capacitors and 1 bidirectional switch tube.

[0021] Optionally, the common voltage source inverter uses a three-phase AC power supply as an energy feedback network.

[0022] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] The present invention discloses a motor simulation method and system based on a Quasi-Z source inverter, the method comprising constructing a mathematical model of a target actual motor and determining the corresponding motor output data; connecting a motor simulator to the output port of a motor driver, and performing pulse width modulation on the motor driver respectively, and performing simulation side inverter control and grid-connected inverter control on the motor simulator; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter is incorporated into a three-phase power grid to simulate the external port characteristics of the target actual motor under different working conditions. The present invention can allow the upper and lower bridge arms to pass directly, adopt a single-stage structure to achieve the purpose of buck-boost, and have the advantages of a small output waveform distortion rate, thereby improving the motor simulation accuracy, anti-interference ability and system power quality, while reducing the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 Schematic diagram of the structure of the motor simulator based on the Quasi-Z source inverter in this embodiment;

[0026] Figure 2 Schematic diagram of the grid-connected control strategy of the energy feedback inverter in this embodiment;

[0027] Figure 3 Schematic diagram of the control strategy of the analog side Quasi-Z source inverter in this embodiment;

[0028] Figure 4 Schematic diagram of current vector synthesis of the analog side Quasi-Z source inverter in this embodiment;

[0029] Figure 5 Schematic diagram of voltage vector synthesis of the energy regenerative inverter in this embodiment;

[0030] Figure 6 The diagram is a duty cycle distribution diagram of the motor simulator module in this embodiment, taking sector I as an example;

[0031] Figure 7 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor load torque in the working condition 1 in this embodiment;

[0032] Figure 8The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor speed in the working condition 1 of the present embodiment;

[0033] Fig. 9 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor output torque in working condition 1 of this embodiment;

[0034] Fig.10 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor port current in the working condition 1 of the present embodiment;

[0035] Fig.11 This is a simulation waveform diagram of the grid-side three-phase current of the motor simulator of the present invention in working condition 1 in this embodiment;

[0036] Fig.12 This is a simulation waveform diagram of the DC bus voltage of the Quasi-Z source inverter on the analog side of the present invention in working condition 1 in this embodiment;

[0037] Fig.13 This is a simulation waveform diagram of the input DC voltage of the Quasi-Z source inverter on the analog side of the present invention in working condition 2 of this embodiment;

[0038] Fig.14 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor speed in working condition 2 of this embodiment;

[0039] Fig.15 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor output torque in working condition 2 of this embodiment;

[0040] Fig.16 The simulation waveform diagram of the motor simulator of the present invention, the motor simulator based on the traditional voltage source inverter and the actual motor port current in the working condition 2 of this embodiment;

[0041] Fig.17 This is a simulation waveform diagram of the DC bus voltage of the Quasi-Z source inverter on the analog side of the present invention in working condition 2 in this embodiment. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The object of the present invention is to provide a motor simulation method and system based on a Quasi-Z source inverter, which can improve the motor simulation accuracy, anti-interference ability and system power quality, while reducing the test cost.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1-Figure 17 As shown, the present invention provides a motor simulation method based on a Quasi-Z source inverter, comprising:

[0046] Step 1: Construct a mathematical model of the target actual motor and determine the corresponding motor output data.

[0047] Step 2: Connect the motor simulator to the output port of the motor driver to form a motor simulation control circuit; wherein the topology of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter.

[0048] Step 3: Based on the motor simulation control circuit, debugging is performed under different working conditions, pulse width modulation is performed on the motor driver, and simulation side inverter control and grid-connected inverter control are performed on the motor simulator.

[0049] Step 4: Compare the motor simulator output data measured after debugging with the motor output data. When the comparison result is in the set difference range, the output port of the motor simulator is connected to the three-phase power grid to simulate the external port characteristics of the target actual motor under different working conditions.

[0050] Based on the above technical solution, the following detailed steps are provided:

[0051] The step 1 comprises:

[0052] 1.1) Establish the mathematical model of the target motor in the abc and dq coordinate systems respectively, including the voltage equation and flux equation describing the electrical characteristics of the motor, the torque equation and speed equation describing the mechanical characteristics of the motor, and the comprehensive formula of the above four equations.

[0053] 1.2) Establish a parametric model of the target motor, use motor body parameter acquisition methods such as experimental measurement, least squares method, model reference adaptive method or extended Kalman filter method to identify and build a table of the required parameters, and determine the corresponding motor output data.

[0054] The structure of step 2 includes:

[0055] 1.1) A motor simulator module consists of an inverter embedded in a Quasi-Z source network, including a simulation-side Quasi-Z source inverter and an energy regeneration inverter.

[0056] 2.2) The Quasi-Z source network includes two coupled inductors, two capacitors and one bidirectional switch. Figure 1 As shown in the structure.

[0057] 2.3) A motor driver module supplies power to and drives the motor simulator system, and a three-phase AC power supply serves as an energy feedback network.

[0058] The step 3) comprises:

[0059] 3.1) A dual space vector modulation strategy is used for the motor simulator module, that is, the Quasi-Z source inverter on the simulation side adopts a grid voltage orientation and DC link voltage feedforward compensation control strategy, while the energy regenerative inverter adopts a fixed AC shaft current control strategy.

[0060] 3.2) The control process of the energy feedback inverter is as follows Figure 2 As shown, the reference signal The measured DC voltage V in By comparison, the d-axis reference current is obtained through the proportional integral (PI) controller The AC side current is converted into a dq reference frame component i d and i q . refer to and The actual current i d and i q Then, the PI controller generates reference voltages, which are passed from dq to the abc reference frame and then sent to the modulator to generate the gate signal.

[0061] 3.3) The control process of the Quasi-Z source inverter on the analog side is as follows Figure 3 As shown, the inverter AC side voltage v oabc is converted to and To the dq frame and get the analog side control system angle through the phase-locked loop (PLL), and then the voltage is input to the target motor model to generate the reference stator current and Measure the inverter output current i oabc , and converted to i d and i q The comparison was made with the reference values ​​generated by the established target motor model. and i d 、i q The error between them is obtained by PI controller and and convert to and The DC side of the Quasi-Z source network uses DC link voltage feedforward compensation control, and the reference signal The measured DC voltage V in Add and divide by 2 to get the reference voltage of capacitor C1 The actual measured voltage V C1 Comparison is performed and the pulse gate signal is generated by inputting it into the modulator through the PI controller.

[0062] 3.4) The switching mode of the energy regenerative inverter can be divided into two states: effective vector state and zero vector state, as shown in Table 1 and Table 2.

[0063] Table 1 All current space vector tables of the energy regenerative inverter of the motor simulator module

[0064] Serial number <![CDATA[S Ap ,S Bp ,S Cp ]]> <![CDATA[S An ,S Bn ,S Cn ]]> Vector describe 1 1，0，0 0，1，1 <![CDATA[U1]]> Effective vector 2 1，1，0 0，0，1 <![CDATA[U2]]> Effective vector 3 0，1，0 1，0，1 <![CDATA[U3]]> Effective vector 4 0，1，1 1，0，0 <![CDATA[U4]]> Effective vector 5 0，0，1 1，1，0 <![CDATA[U5]]> Effective vector 6 1，0，1 0，1，0 <![CDATA[U6]]> Effective vector 7 0，0，0 1，1，1 <![CDATA[U7]]> Zero Vector 8 1，1，1 0，0，0 <![CDATA[U8]]> Zero Vector

[0065] Table 2 Switching status table of each sector of the energy feedback inverter of the motor simulator module

[0066] Sector I II III IV V VI <![CDATA[U a or U' a ]]> <![CDATA[U1]]> <![CDATA[U2]]> <![CDATA[U3]]> <![CDATA[U4]]> <![CDATA[U5]]> <![CDATA[U6]]> <![CDATA[U b or U' b ]]> <![CDATA[U2]]> <![CDATA[U3]]> <![CDATA[U4]]> <![CDATA[U5]]> <![CDATA[U6]]> <![CDATA[U1]]> <![CDATA[U z1 or U' z1 ]]> <![CDATA[U7]]> <![CDATA[U8]]> <![CDATA[U7]]> <![CDATA[U8]]> <![CDATA[U7]]> <![CDATA[U8]]> <![CDATA[U z2 or U' z2 ]]> <![CDATA[U8]]> <![CDATA[U7]]> <![CDATA[U8]]> <![CDATA[U7]]> <![CDATA[U8]]> <![CDATA[U7]]>

[0067] 3.5) The switching mode of the Quasi-Z source inverter on the analog side can be divided into a direct zero vector state, an effective vector state and a zero vector state, as shown in Tables 3 and 4. When the direct zero vector is inserted into the zero state of the Quasi-Z source network, the upper and lower bridge arms of the inverter are turned on at the same time to boost the voltage.

[0068] Table 3 All voltage space vector tables of Quasi-Z source inverter on the simulation side of the motor simulator module

[0069]

[0070] Table 4 Switching status table of each sector of Quasi-Z source inverter on the simulation side of the motor simulator module

[0071] Sector I II III IV V VI <![CDATA[I a ]]> <![CDATA[I1]]> <![CDATA[I2]]> <![CDATA[I3]]> <![CDATA[I4]]> <![CDATA[I5]]> <![CDATA[I6]]> <![CDATA[I b ]]> <![CDATA[I2]]> <![CDATA[I3]]> <![CDATA[I4]]> <![CDATA[I5]]> <![CDATA[I6]]> <![CDATA[I1]]> <![CDATA[I z ]]> <![CDATA[I7]]> <![CDATA[I8]]> <![CDATA[I8]]> <![CDATA[I9]]> <![CDATA[I9]]> <![CDATA[I7]]> <![CDATA[I st ]]> <![CDATA[I 11 ]]> <![CDATA[I 14 ]]> <![CDATA[I 12 ]]> <![CDATA[I 15 ]]> <![CDATA[I 10 ]]> <![CDATA[I 13 ]]>

[0072] 3.6) Calculation of vector duty cycle. The space vector duty cycles of the energy regenerative inverter and the analog side Quasi-Z source inverter are calculated as follows:

[0073]

[0074] Among them, θ i is the angle of the input current vector of the energy feedback inverter, θ o is the angle of the output voltage vector of the Quasi-Z source inverter on the analog side, d α d β d st and d 0r is the duty cycle of different current vectors in a control cycle, d αμ d βμ d αv d βv d α0i and d β0i are the duty cycle of the output voltage vector in one control cycle respectively.

[0075] 3.7) Switch state allocation: The switch state obtained in steps 3.4 and 3.5 and the duty cycle in a control cycle are used Figure 5 The method shown is distributed to control the switching devices of the inverter in the motor simulator.

[0076] When the analog side Quasi-Z source inverter reference current vector I ref When falling into any sector, the reference current vector I ref The two adjacent valid state vectors I of the sector a and I b , and the zero state vector I z and the through state zero vector I st Synthesis, effective state vector I a and I b Respectively through the duty cycle d α and d β , zero state vector I z By duty cycle d 0r , through state zero vector I st By duty cycle d st , to modulate the six bidirectional switches S of the inverter ap , S bp , S cp , S an , S bn and S cn , and the switching state of a bidirectional switch tube S in the Quasi-Z source network in the Quasi-Z source inverter.

[0077] When the energy feedback inverter reference voltage vector V1 falls into any sector, the reference voltage vector V1 is composed of two adjacent valid state vectors U a and U b , and two zero state vectors U z1 and U z2 Synthesis, effective state vector U a By duty cycle d αμ and d βμ , the effective state vector U b By duty cycle d αv and d βv , zero state vector U z1 By duty cycle d a0i , zero state vector U z2 By duty cycle d 0r and d st , to modulate the six bidirectional switches S of the inverter Ap , S Bp , S Cp , S An , S Bn and S Cn The switch status.

[0078] Based on the above specific steps, the simulation is performed as shown below.

[0079] The simulation model of the motor simulator system was built on the MATLAB / Simulink platform and compared with the drive system of the actual motor, which was obtained from the motor library provided by the simulation platform. The DC side voltage of the drive and the DC side voltage of the motor simulator module are both 560V, and the switching frequency of the voltage source inverter is 10kHz.

[0080] Simulation condition 1: In order to verify the motor simulator's ability to simulate no-load starting and load changes of the motor, a speed of 3000 r / min is given, and no-load starting is performed at 0s; a load torque of 60 Nm is applied at 0.3s; and the load torque is reduced to 30 Nm at 0.6s. Figure 7-Figure 12 The figure shows the simulated output waveforms of the motor simulator module based on the Quasi-Z source inverter, the motor simulator module based on the traditional voltage source inverter, and the actual motor under simulation condition 1. Figure 7 It can be seen that the initial running state of the motor is no-load, when 0.3s, 60Nm load torque is added, and when 0.6s, it is reduced to 30Nm load torque. The Quasi-Z source network stabilizes the voltage of the input voltage source inverter at the required value, thereby ensuring that the motor speed is maintained at 3000r / min, such as Figure 8 shown by Fig. 9It can be seen that the motor torque is maintained at 0 Nm before 0.3 s, maintained at 60 Nm from 0.3 to 0.6 s, and maintained at 30 Nm after 0.6 s, and the stator three-phase current simulated by the motor simulator module remains stable, as shown in Figure 2. Fig.10 shown. Fig.11 The current waveform of the energy feedback inverter is shown in FIG. 1 . It can be seen that it is a three-level output, indicating the correctness of the space voltage vector modulation designed by the present invention. When the motor changes from a no-load state to a load state, in order to maintain the stable operation of the motor simulator system, the DC side voltage of the motor simulator module is boosted from 560V to 800V through the Quasi-Z source network, as shown in FIG. Fig.12 As shown, the influence of load on the stable operation of the system is reduced. Figure 8-Figure 10 The figure shows a comparison of the output waveforms of a motor simulator module based on a Quasi-Z source inverter and a motor simulator module based on a traditional voltage source inverter, indicating the feasibility and stability of the operation of the motor simulator system proposed in the present invention.

[0081] Simulation condition 2: In order to verify the motor simulator's simulation capability of motor load starting and simulator input DC voltage changes, the given speed is 3000r / min, the given load torque is 10Nm, and the simulator input DC voltage is 560V at 0s and drops to 500V at 0.3s. Figure 13-Figure 17 Shown are the simulated output waveforms of the motor simulator module based on the Quasi-Z source inverter, the motor simulator module based on the traditional voltage source inverter, and the actual motor under simulation condition 2. Fig.13 Input the DC voltage change curve to the simulator. The Quasi-Z source network stabilizes the voltage of the input voltage source inverter at the required value, thereby ensuring that the motor speed is maintained at 3000r / min, such as Fig.14 shown by Fig.15 It can be seen that the motor torque is maintained at 10Nm, and the stator three-phase current simulated by the motor simulator module remains stable, as shown in Fig.16 When the simulator input DC source voltage changes, the motor simulator module DC side voltage is boosted to 800V through the Quasi-Z source network, as shown in Fig.17 As shown, it is demonstrated that the Quasi-Z source network DC link voltage feed-forward compensation control strategy adopted by the present invention is correct. Figure 14-16 The figure shows a comparison of the output waveforms of a motor simulator module based on a Quasi-Z source inverter and a motor simulator module based on a traditional voltage source inverter, which also demonstrates the stability and good dynamic characteristics of the motor simulator system proposed in the present invention compared to traditional motor simulators.

[0082] In summary, through Figure 8-Figure 10 , Figure 14-16Comparison of the output waveforms of the motor simulator module based on the Quasi-Z source inverter, the motor simulator module based on the traditional voltage source inverter, and the actual motor. It can be seen that the motor simulator module based on the Quasi-Z source inverter has a smaller overshoot of the output torque and speed, a faster adjustment time, and a smaller steady-state error, which is closer to the output of the actual motor; the simulated stator three-phase current is more stable than the stator three-phase current simulated by the motor simulator module based on the traditional voltage source inverter, and has a better tracking effect on the stator three-phase current of the actual motor, indicating that the motor simulator system based on the Quasi-Z source inverter proposed in the present invention has good simulation capabilities for the actual motor and has better dynamic response characteristics and better simulation effects than the motor simulator based on the general voltage source inverter.

[0083] It can be seen that this solution has the following beneficial effects:

[0084] First of all, the motor simulation method based on the Quasi-Z source inverter provided by the present invention does not require the use of an actual motor for testing, and can protect the load from harsh operating conditions, greatly reducing safety requirements, and can select a variety of test schemes to flexibly and comprehensively test the performance of the motor driver under different working conditions, and has a wide range of applications.

[0085] The introduction of the Quasi-Z source network improves the safety of the inverter's active devices, enhances anti-interference capabilities, solves inherent defects of traditional inverters such as the need to consider dead time and its effects, improves the quality of the output voltage, and improves the reliability of the inverter system and the quality of output power. In addition, the topology structure disclosed in this embodiment uses an integrated design for DC-DC and DC-AC conversion, allows direct connection between the upper and lower bridge arms, and uses a single-stage structure to achieve the purpose of stepping up and down, which greatly saves the inverter manufacturing cost.

[0086] In addition, the present invention also provides a motor simulation system based on a Quasi-Z source inverter, which is applied to the motor simulation method as described above, including: a motor drive, a motor simulator and a three-phase power grid connected in sequence; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter.

[0087] The Quasi-Z source network in the Quasi-Z source inverter is composed of two coupled inductors, two capacitors and one bidirectional switch tube. The common voltage source inverter uses a three-phase AC power supply as an energy feedback network.

[0088] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0089] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A motor simulation method based on Quasi-Z source inverter, characterized in that: include: Construct a mathematical model of the target actual motor and determine the corresponding motor output data; The motor simulator is connected to the output port of the motor driver to form a motor simulation control circuit; wherein the topological structure of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter; Based on the motor simulation control circuit, the motor driver is debugged under different working conditions, pulse width modulation is performed on the motor driver, and the motor simulator is controlled by a simulation side inverter and a grid-connected inverter; The motor simulator output data measured after debugging is compared with the motor output data. When the comparison result is within the set difference interval, the output port of the motor simulator is connected to the three-phase power grid to simulate the external port characteristics of the target actual motor under different working conditions; The dual space vector modulation strategy is used for the motor simulator module during the debugging; the dual space vector modulation strategy includes a control strategy for grid voltage orientation and DC link voltage feedforward compensation of the simulation side Quasi-Z source inverter, and a control strategy for AC side orientation of the energy feedback inverter. Control strategy of shaft current; The modulation process of the analog side Quasi-Z source inverter is: When the analog side Quasi-Z source inverter reference current vector When falling into any sector, the reference current vector The two adjacent valid state vectors of the sector and , and the zero state vector and through-state zero vector Synthesized, effective state vector and Duty cycle and , zero state vector By duty cycle , to modulate the six bidirectional switches of the inverter , , , , and , through state zero vector By duty cycle , to modulate a bidirectional switch in the Quasi-Z source network of the Quasi-Z source inverter The switch status; The modulation process of the energy feedback inverter is: When the energy feedback inverter reference voltage vector When falling into any sector, the reference voltage vector The two adjacent valid state vectors of the sector and , and two zero state vectors and Synthesized, effective state vector U a By duty cycle and , the effective state vector By duty cycle and , zero state vector By duty cycle , zero state vector By duty cycle and , to modulate the six bidirectional switches of the inverter , , , , and The switch status.

2. The motor simulation method based on Quasi-Z source inverter according to claim 1, characterized in that: The step of constructing a mathematical model of the target actual motor and determining the corresponding motor output data specifically includes: The target actual motor is respectively Coordinate system and A mathematical model of a target motor is established in the coordinate system, wherein the mathematical model of the target motor includes a voltage equation and a flux equation describing the electrical characteristics of the motor, a torque equation and a speed equation describing the mechanical characteristics of the motor, and a comprehensive formula of the four equations; The motor body parameter acquisition method is used to identify the required parameters and build a table, and the motor output data corresponding to the target actual motor is determined; the motor body parameter acquisition method includes: experimental measurement, least squares method, model reference adaptive method and extended Kalman filter method.

3. A motor simulation system based on a Quasi-Z source inverter, applied to the motor simulation method as described in any one of claims 1-2, characterized in that: include: A motor driver, a motor simulator and a three-phase power grid are connected in sequence; wherein the topology of the motor simulator is composed of a first-level Quasi-Z source inverter and a first-level ordinary voltage source inverter connected back to back; the ordinary voltage source inverter adopts an energy feedback inverter; the Quasi-Z source network in the Quasi-Z source inverter is composed of 2 coupled inductors, 2 capacitors and 1 bidirectional switch tube.

4. The motor simulation system based on Quasi-Z source inverter according to claim 3, characterized in that: The common voltage source inverter adopts a three-phase AC power supply as an energy feedback network.

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