Open-winding motors and their control methods and devices, computer-readable storage media

Abstract

This invention discloses an open-winding motor, its control method and apparatus, and a computer-readable storage medium. The method includes: acquiring the motor's current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage; acquiring the historical zero-phase feedback current after N sampling times prior to the current cycle, where N is a positive integer; acquiring the motor's zero-phase setpoint voltage based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity; acquiring the duty cycles of the first and second inverters based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage; and controlling the motor based on the duty cycles. Therefore, this method only requires storing the historical zero-phase feedback current from one cycle ago, eliminating the need for complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a control method for an open-winding motor, a computer-readable storage medium, an open-winding motor, and a control device for an open-winding motor. Background Technology

[0002] In recent years, the application scope of motor control systems has become increasingly wide, and the demand in high-speed operation fields has also increased. To achieve high-speed motor operation, the required motor terminal voltage has also increased, leading to the adoption of high-voltage inverters and field weakening flux control. For high-voltage inverters, boost circuits are typically used; however, as the voltage withstand capability of semiconductor components and smoothing capacitors increases, the application cost also increases, thus limiting the possibility of significantly increasing voltage. Field weakening flux control consumes excess power that does not contribute to motor torque, making its application effect less than ideal from an energy-saving perspective.

[0003] To solve the above problems, the current technical solution is to pull out the windings of the three-phase motor and drive it with two frequency converters. Compared with the conventional Y-connected three-phase motor, the open-winding motor system can provide nearly twice the DC bus voltage utilization rate.

[0004] Furthermore, since the zero-phase current in the aforementioned open-winding motor system leads to decreased motor efficiency and torque ripple, a zero-phase current suppression module is typically installed to eliminate this zero-phase current at three times the frequency. The control block diagram of the zero-phase current suppression module is shown below. Figure 1 As shown, the controller consists of a proportional control block 21A and a resonant control block 21B (hereinafter referred to as the PR (Proportion Resonant) controller). Since the frequency of the zero-phase current is three times the frequency of the motor phase current, it will be affected by the current detection delay during high-speed operation. Therefore, a further step is to insert a control block such as... Figure 2 The phase forward compensation block 21C shown and the gain compensation block 21D that cancels the nonlinear gain generated by the phase forward compensation block 21C improve the phase characteristics, thereby improving the control characteristics of the motor when it is running at high speed.

[0005] The above Figure 2 The corresponding method is then specified and implemented on a real machine, such as Figure 3 The Simulink model shown has a very large amount of computation in the gain compensation block 21D, including logarithmic calculations. The phase forward compensation block 21C is also a control block containing a transfer function with variable coefficients. If the software is installed on a computer for calculation, the computer's computational load will be very heavy and the code will be very complex, making it difficult to implement the above technical solutions in practice. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to propose a control method for an open-winding motor that only requires storing the historical zero-phase feedback current from one cycle ago, without requiring complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0007] A second objective of this invention is to provide a computer-readable storage medium.

[0008] The third objective of this invention is to provide an open-winding motor.

[0009] The fourth objective of this invention is to provide a control device for an open-winding motor.

[0010] To achieve the above objectives, a first aspect of the present invention provides a control method for an open-winding motor. The motor includes a three-phase winding, with the two ends of the three-phase winding connected to a first inverter and a second inverter, respectively. The first inverter and the second inverter share a DC bus. The method includes: acquiring the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor at the current moment; acquiring the historical zero-phase feedback current after N sampling times prior to one cycle of the zero-phase feedback current, where N is a positive integer; acquiring the zero-phase setpoint voltage of the motor based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity; acquiring the duty cycle of the first inverter and the second inverter based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage; and controlling the motor based on the duty cycle.

[0011] According to an embodiment of the present invention, the control method for an open-winding motor first acquires the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor at the current moment. Then, it acquires the historical zero-phase feedback current after N sampling times prior to the current cycle. Based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity, it acquires the zero-phase setpoint voltage of the motor. Based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage, it acquires the duty cycles of the first and second inverters. Finally, it controls the motor based on the duty cycles. Therefore, this method only requires storing the historical zero-phase feedback current from one cycle ago, eliminating the need for complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0012] In addition, the control method for an open-winding motor according to the above embodiments of the present invention may also have the following additional technical features:

[0013] According to one embodiment of the present invention, obtaining the historical zero-phase feedback current after N sampling times before one cycle of the zero-phase feedback current includes: obtaining the period of the zero-phase feedback current based on the feedback angular velocity; obtaining N sampling times based on the sampling frequency of the zero-phase feedback current; and obtaining the historical zero-phase feedback current from a historical database based on the time difference between the period and N sampling times.

[0014] According to one embodiment of the present invention, the period of the zero-phase feedback current is three times the feedback angular velocity.

[0015] According to one embodiment of the present invention, obtaining the zero-phase given voltage of a motor based on the zero-phase given current, the zero-phase feedback current, the historical zero-phase feedback current, and the feedback angular velocity includes: performing a first proportional control on the current difference between the zero-phase given current and the zero-phase feedback current to obtain a first voltage; performing resonance control on the current difference between the zero-phase given current and the historical zero-phase feedback current to obtain a second voltage; and summing the first voltage and the second voltage to obtain the zero-phase given voltage.

[0016] According to one embodiment of the present invention, a second voltage is obtained by resonant control of the current difference between the zero-phase given current and the historical zero-phase feedback current, including: obtaining a third voltage by performing a second proportional control on the current difference between the zero-phase given current and the historical zero-phase feedback current; obtaining a fourth voltage by performing integral control on the product of the square of three times the feedback angular velocity and the second voltage at the previous moment; and obtaining the second voltage at the current moment by performing integral control on the voltage difference between the third voltage and the fourth voltage.

[0017] According to one embodiment of the present invention, obtaining the zero-phase feedback current, feedback angular velocity, and rotor position angle of a motor at the current moment includes: obtaining the three-phase current of the motor; performing coordinate transformation on the three-phase current to obtain the q-axis feedback current, d-axis feedback current, and zero-phase feedback current of the motor; and performing position estimation based on the q-axis feedback current and d-axis feedback current to obtain the feedback angular velocity and rotor position angle.

[0018] According to one embodiment of the present invention, obtaining the q-axis voltage and d-axis voltage of a motor at the current moment includes: obtaining a given angular velocity and dq-axis voltage of the motor; performing speed control on the angle difference between the given angular velocity and the feedback angular velocity to obtain a given q-axis current of the motor; performing field weakening control on the voltage difference between the DC bus voltage and the dq-axis voltage to obtain a given d-axis current of the motor; and performing current control based on the given q-axis current, the given d-axis current, the q-axis feedback current, and the d-axis feedback current to obtain the q-axis voltage and d-axis voltage.

[0019] To achieve the above objectives, a second aspect of the present invention provides a computer-readable storage medium storing a control program for an open-winding motor, which, when executed by a processor, implements the steps of the above method.

[0020] According to the computer-readable storage medium of the present invention, based on the above method, only the historical zero-phase feedback current from one cycle ago needs to be stored, without the need for complex and heavy data calculation processing, and can be implemented using a low-cost microcomputer.

[0021] To achieve the above objectives, a third aspect of the present invention provides an open-winding motor, comprising: a three-phase winding, a first inverter, a second inverter, and a control device, wherein the two ends of the three-phase winding are respectively connected to the first inverter and the second inverter, and the first inverter and the second inverter share a DC bus; the control device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the above method.

[0022] According to the open-winding motor of the present invention, based on the above control method, it is only necessary to store the historical zero-phase feedback current one cycle ago, without performing complex and heavy data calculation processing, and can be implemented using a low-cost microcomputer.

[0023] To achieve the above objectives, a control device for an open-winding motor is provided in a fourth aspect embodiment of the present invention. The motor includes a three-phase winding, with the two ends of the three-phase winding connected to a first inverter and a second inverter, respectively. The first inverter and the second inverter share a DC bus. The device includes: an acquisition module for acquiring the zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor at the current moment; a PR control module for acquiring the historical zero-phase feedback current after one cycle of the zero-phase feedback current and after N sampling times, and acquiring the zero-phase setpoint voltage of the motor based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity; a duty cycle generation module for acquiring the duty cycle of the first inverter and the second inverter based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage; and a control module for controlling the motor based on the duty cycle.

[0024] According to an embodiment of the present invention, the control device for an open-winding motor acquires the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor through an acquisition module. It acquires the historical zero-phase feedback current after N sampling times prior to the current cycle through a PR control module, and obtains the zero-phase setpoint voltage of the motor based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity. A duty cycle generation module obtains the duty cycles of the first and second inverters based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage. The control module controls the motor based on the duty cycles. Therefore, this device only needs to store the historical zero-phase feedback current from one cycle ago, eliminating the need for complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0025] In addition, the control device for the open-winding motor according to the above embodiments of the present invention may also have the following additional technical features:

[0026] According to one embodiment of the present invention, the PR control module obtains the historical zero-phase feedback current after N sampling times before one cycle of the zero-phase feedback current, specifically for: obtaining the cycle of the zero-phase feedback current based on the feedback angular velocity; obtaining N sampling times based on the sampling frequency of the zero-phase feedback current; and obtaining the historical zero-phase feedback current from the historical database based on the time difference between the cycle and N sampling times.

[0027] According to one embodiment of the present invention, the period of the zero-phase feedback current in the PR control module is three times the feedback angular velocity.

[0028] According to one embodiment of the present invention, the duty cycle generation module obtains the zero-phase given voltage of the motor based on the zero-phase given current, the zero-phase feedback current, the historical zero-phase feedback current, and the feedback angular velocity. Specifically, it is used to: perform a first proportional control on the current difference between the zero-phase given current and the zero-phase feedback current to obtain a first voltage; perform resonance control on the current difference between the zero-phase given current and the historical zero-phase feedback current to obtain a second voltage; and sum the first voltage and the second voltage to obtain the zero-phase given voltage.

[0029] According to one embodiment of the present invention, the duty cycle generation module performs resonant control on the current difference between the zero-phase given current and the historical zero-phase feedback current to obtain a second voltage. Specifically, it is used to: perform a second proportional control on the current difference between the zero-phase given current and the historical zero-phase feedback current to obtain a third voltage; perform integral control on the product of the square of three times the feedback angular velocity and the second voltage at the previous moment to obtain a fourth voltage; and perform integral control on the voltage difference between the third voltage and the fourth voltage to obtain the second voltage at the current moment.

[0030] According to one embodiment of the present invention, the acquisition module acquires the zero-phase feedback current, feedback angular velocity, and rotor position angle of the motor at the current moment, specifically for: acquiring the three-phase current of the motor; performing coordinate transformation on the three-phase current to obtain the q-axis feedback current, d-axis feedback current, and zero-phase feedback current of the motor; and performing position estimation based on the q-axis feedback current and d-axis feedback current to obtain the feedback angular velocity and rotor position angle.

[0031] According to one embodiment of the present invention, the acquisition module acquires the q-axis voltage and d-axis voltage of the motor at the current moment, specifically for: acquiring the given angular velocity and dq-axis voltage of the motor; performing speed control on the angle difference between the given angular velocity and the feedback angular velocity to obtain the given q-axis current of the motor; performing field weakening control on the voltage difference between the DC bus voltage and the dq-axis voltage to obtain the given d-axis current of the motor; and performing current control based on the given q-axis current, the given d-axis current, the q-axis feedback current, and the d-axis feedback current to obtain the q-axis voltage and d-axis voltage.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the PR controller block in the relevant technology;

[0034] Figure 2 A schematic diagram of a PR controller block for inserting phase shift compensation and gain compensation blocks in related technologies;

[0035] Figure 3 A Simulink model diagram illustrating the insertion of phase shift compensation blocks and gain compensation blocks in related technologies;

[0036] Figure 4 A flowchart of a control method for an open-winding motor according to an embodiment of the present invention;

[0037] Figure 5 This is a circuit connection diagram of an open-winding motor according to an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the control block of an open-winding motor according to an embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of a sampling time 1 cycle prior to a specific embodiment of the present invention;

[0040] Figure 8 This is a block diagram of a PR controller in a control method according to an embodiment of the present invention;

[0041] Figure 9 This is a schematic diagram of a Simulink model of a control method according to an embodiment of the present invention;

[0042] Figure 10 This is a schematic diagram of simulation results for a control method of an open-winding motor according to an embodiment of the present invention;

[0043] Figure 11 This is a schematic diagram of the simulation results of the control method in the related technology;

[0044] Figure 12 This is a block diagram of an open-winding motor according to an embodiment of the present invention;

[0045] Figure 13 This is a block diagram of a control device for an open-winding motor according to an embodiment of the present invention. Detailed Implementation

[0046] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0047] The following description, with reference to the accompanying drawings, outlines the control method for an open-winding motor, a computer-readable storage medium, an open-winding motor, and a control device for an open-winding motor, all according to embodiments of the present invention.

[0048] Figure 4 This is a flowchart of a control method for an open-winding motor according to an embodiment of the present invention.

[0049] like Figure 5 As shown, in one embodiment of the present invention, the motor includes a three-phase winding 10, and the two ends of the three-phase winding 10 are respectively connected to a first inverter 20 and a second inverter 30. The first inverter 20 and the second inverter 30 share a DC bus.

[0050] Specifically, the aforementioned motor has a three-phase winding 10 with an open winding structure. The first inverter 20 and the second inverter 30 employ three-phase full-bridge rectifiers, with each bridge arm consisting of at least one power electronic device connected in series. In this embodiment, the switching device uses IGBTs (Insulated Gate Bipolar Transistors), meaning each inverter includes six IGBTs. Furthermore, the DC sides of the first inverter 20 and the second inverter 30 share the same DC power supply dc, meaning both are powered by the same DC power supply dc. The input voltage of both the first inverter 20 and the second inverter 30 is V. dcOne end of any phase winding in the motor is connected to the center node of the corresponding upper and lower bridge arm in the first inverter 20, and the other end is connected to the center node of the corresponding upper and lower bridge arm in the second inverter 30, as shown below. Figure 1 As shown, one end of the three-phase winding 10 is connected to nodes A, B and C of the first inverter 20, and the other end is connected to nodes D, E and F of the second inverter 30.

[0051] When the power supply for the first frequency converter 10 and the second frequency converter 20 is the same DC power supply (dc), the zero-phase current of the motor will flow through the DC link path, and the equations for the motor's voltage and current are as follows:

[0052]

[0053] I0=(I u +I v +I w ) / 3

[0054] V0=(V u +V v +V w ) / 3

[0055] Where p is the differential operator, ω e Let θ be the electrical angular velocity. e For electrical angle, I d I is the d-axis current. q I is the q-phase current, I0 is the zero-phase current, and V d V is the d-axis voltage. q V0 is the q-axis voltage, and L is the zero-phase voltage. d For the d-axis inductance, L q For q-axis self-inductance, l s For leakage flux, Ψ d Let Ψ0 be the fundamental frequency of the magnetic flux, δ be the third harmonic component of the magnetic flux, and I be the phase difference between the d-axis and the magnetic flux. u I v and I w V represents the three-phase current of the motor. u V v and V w This represents the three-phase voltage of the motor.

[0056] This shows that the frequency of the zero-phase current I0 of the open-winding motor system is three times the frequency of the motor phase current.

[0057] like Figure 4 As shown, the control method for an open-winding motor according to an embodiment of the present invention may include:

[0058] S1, obtain the current zero-phase given current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage and DC bus voltage of the motor at the current moment.

[0059] like Figure 6 As shown, according to one embodiment of the present invention, obtaining the zero-phase feedback current I0, feedback angular velocity ω, and rotor position angle θ of the motor at the current moment includes: obtaining the three-phase current (I0, I ... and rotor position angle θ of the motor at the current moment. u I v and I w ); for three-phase current (I u I v and I w The q-axis feedback current I of the motor is obtained by performing coordinate transformation. q d-axis feedback current I d And the zero-phase feedback current I0; based on the q-axis feedback current I q and d-axis feedback current I d Position estimation is performed to obtain the feedback angular velocity ω and the rotor position angle θ.

[0060] Specifically, the three-phase current I of the motor can first be measured by a current sensor installed in the circuit. u I v and I w Real-time detection and acquisition can be performed, for example, by acquiring the current I through a current sensor installed on the circuit formed by connecting nodes A and D. u The current I is obtained by a current sensor installed on the circuit formed by connecting nodes B and E. v The current I is obtained by a current sensor installed on the circuit formed by connecting nodes C and F. w Then detect the obtained I u I v and I w The input is fed into coordinate transformation module 1 for coordinate transformation to obtain the feedback current I. q I d And I0, the feedback current I along the q-axis and d-axis q I d The output is sent to position estimation module 2, and the position of the rotor in the motor is estimated to obtain the feedback angular velocity ω and the rotor position angle θ.

[0061] Continue to refer to Figure 6 According to one embodiment of the present invention, the q-axis voltage V of the motor at the current moment is obtained. q and d-axis voltage V d This includes: obtaining the given angular velocity ω of the motor. ref and dq axis voltage V dq For a given angular velocity ω refThe angular difference between the current and the feedback angular velocity ω is used to control the speed and obtain the q-axis setpoint current I of the motor. qref For DC bus voltage V dc With dq axis voltage V dq The voltage difference between the two is used to obtain the d-axis current I of the motor through field weakening control. dref Based on the q-axis given current I qref d-axis given current I dref q-axis feedback current I q and d-axis feedback current I d Current control is used to obtain the q-axis voltage V. q and d-axis voltage V d Wherein, given angular velocity ω ref It can be calibrated according to the actual situation.

[0062] Specifically, given an angular velocity ω ref The feedback angular velocity ω output by the position estimation module 2 is input to the speed control module 3, and the speed control module 3 controls the angular velocity ω. ref The speed control is performed using the difference between the feedback angular velocity ω and the given current I. qref The obtained DC bus voltage V dc With dq axis voltage V dq Input to field weakening control module 4, field weakening control module 4 will V dc and V dq The voltage difference obtained by subtraction is used to obtain the given current I through field weakening control. dref Then, the given current I along the q-axis and d-axis is obtained. qref I dref And the feedback current I of the q-axis and d-axis output by coordinate transformation module 1. q I d The input is sent to the current control module 5, and the current control module 5 controls the q-axis voltage V to obtain the voltage. q and d-axis voltage V d .

[0063] S2, obtains the historical zero-phase feedback current after N sampling times before the one-cycle zero-phase feedback current, where N is a positive integer.

[0064] In other words, the historical data stored one cycle ago, namely the zero-phase feedback current I0 obtained through coordinate transformation one week ago, is called up as the historical zero-phase feedback current corresponding to the current time, and the time difference between the time corresponding to the historical zero-phase feedback current and the current time is the unit cycle time minus N sampling times.

[0065] It should be noted that the sampling time mentioned above refers to the unit time of the computer's internal processing, which is usually consistent with the PWM (Pulse Width Modulation) carrier wave.

[0066] The method for obtaining historical zero-phase feedback current is explained in detail below.

[0067] According to one embodiment of the present invention, obtaining the historical zero-phase feedback current N sampling times prior to the zero-phase feedback current I0 in one cycle includes:

[0068] S201, obtain the period T of the zero-phase feedback current I0 based on the feedback angular velocity ω.

[0069] According to one embodiment of the present invention, the period T of the zero-phase feedback current I0 is three times the feedback angular velocity ω.

[0070] S202, obtain the sampling time N based on the sampling frequency of the zero-phase feedback current I0; the sampling frequency can also be set according to the actual application. The single sampling interval t can be calculated from the sampling frequency, so the required sampling time N*t can be obtained by multiplying N by the single sampling interval t.

[0071] S203 retrieves the historical zero-phase feedback current I′0 from the historical database based on the time difference between the sampling time of period T and N.

[0072] In other words, during the application process, it is necessary to store the zero-phase feedback current I0 data from one cycle ago to form a table of the relationship between sampling time and zero-phase feedback current. When the current time is determined to be T2, the memory stores the zero-phase feedback current I0 within the time period T1-T2 (one cycle). The sampling time to be called is determined according to the value of N, that is, the zero-phase feedback current I0 corresponding to the time point TN*t before T2 is retrieved from the historical database and recorded as the historical zero-phase feedback current I′0 corresponding to the current time T2.

[0073] The following explanation uses N=1 as an example. Figure 7 As shown, the current time is T2, then the time one cycle ago is T1 = T2 - T. The memory stores a table of the correspondence between the sampling time and the zero-phase feedback current during the T1-T2 time period to form a historical database. The N*t time to be called is determined to be a sampling time, i.e., t. The time point after T1 has passed one sampling time t is t1. Then, the zero-phase feedback current I0 corresponding to the above historical data at time t1 is retrieved, which is used as the historical zero-phase feedback current I′0 required for the current time T2.

[0074] It should be noted that the value of the positive integer N mentioned above can be set according to the actual situation. For example, when the phase compensation in this control method only considers the sampling delay of the current sensor, it can be set to 1 sampling time, i.e., N=1. If the phase delay of the current sensor itself is also considered, using 2 sampling times can achieve a better control effect, i.e., N=2.

[0075] S3, based on the zero-phase given current I 0ref The zero-phase feedback current I0, historical zero-phase feedback current I′0, and feedback angular velocity ω are used to obtain the zero-phase setpoint voltage V of the motor. Oref .

[0076] like Figure 6 As shown, the zero-phase given current I 0ref The current I0 obtained through coordinate transformation module 1, the historical zero-phase feedback current I′0 obtained above, and the feedback angular velocity ω obtained through position estimation module 2 are input to zero-sequence current suppression module 6, and the voltage V is calculated. 0ref .

[0077] It should be noted that the zero-phase given voltage V of the above-mentioned motor 0ref The method for obtaining it should be selected according to the actual situation. The following is a detailed explanation of the method.

[0078] According to one embodiment of the present invention, based on the zero-phase given current I 0ref The zero-phase feedback current I0, historical zero-phase feedback current I′0, and feedback angular velocity ω are used to obtain the zero-phase setpoint voltage V of the motor. 0ref ,include:

[0079] S301, for zero-phase given current I 0ref The current difference I between the zero-phase feedback current I0 and the zero-phase feedback current I 0dev The first voltage V1 is obtained by performing the first proportional control. The zero-phase given current I... Oref It is always 0.

[0080] like Figure 8 As shown, the zero-phase given current I Oref Subtracting the zero-phase feedback current I0 from the result gives I 0dev =-I0, input proportional control block 21A, that is, with the proportional adjustment coefficient K p The first proportional control is performed to obtain voltage V1. It should be noted that the proportional adjustment coefficient used in the first proportional control can be set according to the actual application.

[0081] S302, for zero-phase given current I 0ref The second voltage V2 is obtained by resonant control of the current difference between the current and the historical zero-phase feedback current I′0.

[0082] Among them, I 0ref =0, that is, the current I 0ref The current difference -I′0 obtained by subtracting the historical zero-phase feedback current I′0 is input to the resonance control block 21B for resonance control, and the second voltage V2 is calculated.

[0083] According to an embodiment of the present invention, a zero-phase given current I 0ref The second voltage V2 is obtained by resonant control of the current difference between the current and the historical zero-phase feedback current, which may include: controlling the zero-phase given current I 0ref The third voltage V3 is obtained by performing a second proportional control on the current difference between the historical zero-phase feedback current I′0 and the feedback current. The fourth voltage V4 is obtained by performing integral control on the product of the square of three times the feedback angular velocity ω and the second voltage V2 at the previous moment. The second voltage V2 at the current moment is obtained by performing integral control on the voltage difference between the third voltage V3 and the fourth voltage V4.

[0084] Specifically, the current I obtained above 0ref The current difference -I′0 between the current and the historical zero-phase feedback current I′0 is input to the proportional control module to proportionally control the adjustment coefficient K. r Perform a second proportional control operation to calculate the third voltage V3, and substitute the feedback angular velocity ω obtained by the position estimation module 2 into the formula ω0=(3ω). 2 ω0 is calculated, then ω0 is multiplied by the second voltage V2 obtained at the previous moment, and integral control is performed to calculate the fourth voltage V4. The voltage difference obtained by subtracting the third voltage V3 from the fourth voltage V4 is then used for integral control to calculate the second voltage V2 at the current moment.

[0085] In other words, during the calculation of V2, it is necessary to save the current V2 value so that it can be substituted into the calculation to obtain the V2 value at the next time step. The parameters required for the above calculation can be set according to the actual situation.

[0086] Furthermore, the method for obtaining the second voltage V2 is also related to the motor speed n. According to an embodiment of the present invention, the method further includes: when the motor speed n is determined to be greater than a preset speed n based on the feedback angular velocity ω. ref At that time, given a zero-phase current I 0ref The second voltage V2 is obtained by resonant control using the current difference between the current and the historical zero-phase feedback current; when the motor speed n is determined to be less than or equal to the preset speed n based on the feedback angular velocity ω. ref At that time, given a zero-phase current I 0ref The current difference I between the zero-phase feedback current I0 and the zero-phase feedback current I 0dev A second voltage V2 is obtained by performing resonance control. The preset rotational speed n... refIt can be configured according to the actual application.

[0087] Specifically, the current motor speed n is calculated based on the feedback angular velocity ω. If the unit of ω is rad / s and the unit of speed n is r / min, then the relationship between angular velocity and speed can be expressed by the formula ω = n × π / 30. Therefore, the current motor speed n can be calculated using this formula, and then the current speed n is compared with the preset speed n. ref For comparison, if n is greater than n ref The zero-phase given current I 0ref The current difference between the current and the historical zero-phase feedback current is input to the resonant control block 21B, and the second voltage V2 is calculated. If n is less than or equal to n... ref Then I is controlled by resonance. 0ref The difference between the current and I0 is used to obtain the second voltage V2. That is, based on the current motor speed n and the preset speed n... ref The magnitude of the signal determines the input quantity of the resonance control block 21B, which is then controlled and modified. In other words, the repetitive control block 21E does not perform compensation in the low-speed region of the motor.

[0088] S303, summing the first voltage V1 and the second voltage V2 to obtain the zero-phase given voltage V 0ref .

[0089] In other words, the zero-phase given voltage V 0ref The calculation formula is:

[0090] V 0ref =V1+V2

[0091] Among them, V 0ref The zero-phase voltage is given, V1 is the first voltage, and V2 is the second voltage.

[0092] S4, based on the zero-phase given voltage V 0ref Rotor position angle θ, q-axis voltage V q d-axis voltage V d and DC bus voltage V dc Obtain the duty cycle of the first inverter 20 and the second inverter 30.

[0093] Specifically, the V output by the zero-sequence current suppression module mentioned above... 0ref The position estimation module 2 outputs θ, and the current control module outputs V. q V d and DC bus voltage V dcThe input is sent to the space vector modulation module 7, and the duty cycle of the first inverter 20 and the second inverter 30 is calculated by the space vector modulation method. The output is the control signals U1, V1, W1, X1, Y1 and Z1 corresponding to the six transistors in the first inverter 20, and the control signals U2, V2, W2, X2, Y2 and Z2 corresponding to the transistors in the second inverter 30.

[0094] S5 controls the motor according to the duty cycle. That is, the control signals U1, V1, W1, X1, Y1, Z1, U2, V2, W2, X2, Y2, Z2 output by the space vector modulation module 7 are used to control the first inverter 20 and the second inverter 30, thereby realizing the control operation of the motor.

[0095] The control method of this invention first controls the three-phase current I of the motor. u I v and I w The feedback current I is obtained through coordinate transformation module 1. q I d And I0, feedback current I q I d The output enters the position estimation module 2 to obtain the rotor position angle θ and the feedback angular velocity ω. Given the angular velocity ω... ref The feedback angular velocity ω is input to the speed control module 3 to obtain the given current I. qref DC bus voltage V dc With dq axis voltage V dq Input field weakening control module 4 given current I dref Given current I qref I dref and feedback current I q I d The input is sent to the current control module 5, and the voltage V is obtained through the current control module 5. q V d Zero-phase given current I 0ref The current I0, the historical zero-phase feedback current, and the feedback angular velocity ω are input to the zero-sequence current suppression module 6, and the voltage V is calculated. 0ref Finally, the zero-phase given voltage V 0ref Rotor position angle θ, q-axis voltage V q d-axis voltage V d and DC bus voltage V dc The input to the space vector modulation module 7 calculates the duty cycle of the first inverter 20 and the second inverter 30, and outputs control signals U1, V1, W1, X1, Y1, Z1 and U2, V2, W2, X2, Y2, Z2 to the first inverter 20 and the second inverter 30, thereby realizing the control of the motor.

[0096] Among them, the control block in the aforementioned zero-sequence current suppression module 6 is as follows: Figure 8 As shown, the zero-phase given current I 0ref Subtracting the zero-phase feedback current I0 from the input of the proportional control block 21A, i.e., using the proportional adjustment coefficient K, results in the input of the proportional control block 21A. p Perform the first proportional control to obtain the first voltage V1, and then control the current I. 0ref The current difference obtained by subtracting the historical zero-phase feedback current is input to the resonant control block 21B to calculate the second voltage V2. The second voltage V2 obtained by the above control method is added to the first voltage V1 output by the P controller (i.e., the proportional control block 21A) to obtain the zero-phase setpoint voltage V. 0ref .

[0097] Furthermore, the aforementioned control method inserts a K-type control at the front end of the R (Resonant) controller (i.e., resonant control block 21B) of the PR controller. k The control block represented is the repetitive control block 21E, used to improve phase characteristics. This is a concretization of the above control method, resulting in... Figure 9 The Simulink model shown is... Figure 9 In the Simulink model shown, I0 is directly used as the input to the proportional control block 21A, the repetitive control block 21E, and the resonant control block 21B. The feedback angular velocity ω is input to the switch control module, thereby controlling whether the input of the resonant control block 21B is connected to the output of the repetitive control block 21E or I0 based on the ω value. In other words, the ω value determines whether resonant control is applied to the historical zero-phase current I′0 or the zero-phase current I0. Then, the sum of the voltages calculated by blocks 21A and 21B is multiplied by -1 to obtain the result. Figure 8 The corresponding zero-phase given voltage V 0ref .

[0098] The above Figure 8 Zhong K k The control block corresponds to Figure 9 The repetitive control block 21E marked in the figure, taking N=1 as an example, improves the phase characteristics by inputting the historical zero-phase feedback current (zero-phase feedback current I0) one sampling time before the first cycle of the third harmonic component (zero-phase feedback current I0), which is proportional to the motor speed n, into the R controller. In other words, this control method uses the historical zero-phase feedback current corresponding to one sampling time before the first cycle of the zero-phase feedback current I0 as a delay processing.

[0099] Specifically, the motor speed n is first calculated using the feedback angular velocity ω. Then, the period T of the third harmonic, i.e., the period of the zero-phase feedback current I0, is calculated based on the motor speed n. The zero-phase feedback current I0 corresponding to one period T is then stored. If the sampling time is s, the time point Ts can be obtained through the delay time processing block 21F. The zero-phase feedback current I0 corresponding to the time Ts stored in the memory is then retrieved as the historical zero-phase feedback current I′0 and input to the resonance control block 21B. If the current value of the historical zero-phase feedback current I′0 of the third harmonic component one period ago is almost unchanged from the current value of the current feedback current I0, the historical zero-phase feedback current I′0 is regarded as a prediction of the zero-phase feedback current value of the current zero-phase feedback current I0 after one sampling time and then input to the R controller, thereby improving the phase characteristics. The processing method used in the above repetitive control block 21E is simple and does not require complex and heavy calculations such as logarithmic calculations. It can be processed by microcomputer software, reducing application costs.

[0100] Furthermore, the repetitive control block 21E does not perform compensation in the low-speed region of the motor; that is, when the motor speed n is greater than the preset speed n... ref At that time, the zero-phase given current I 0ref The current difference between the obtained historical zero-phase feedback current and the current difference is input into the resonance control block 21B to obtain the second voltage V2. When the motor speed n is less than or equal to the preset speed n ref At that time, the zero-phase given current I is directly applied. 0ref The current difference input I between the zero-phase feedback current I0 and the zero-phase feedback current I0 0dev The second voltage V2 is obtained by inputting the resonance control block 21B to control the resonance.

[0101] In summary, this method only requires storing the sampled values ​​of the third harmonic component of the three-phase motor within one cycle in the memory, and then extracting the data one sampling time before it one cycle ago to complete the lag processing application. Therefore, it does not require complex and heavy computational processing such as logarithmic calculation, and the above control process can be implemented with a low-cost microcomputer.

[0102] Furthermore, the above control method is highly effective, especially suitable for applications involving motors with relatively slow acceleration and deceleration, such as air conditioners. Taking a motor speed of 6000 rpm as an example, a simulation of the above control method is performed. Figure 10 The display shows that Figure 8 and Figure 9 The simulation results of the control of the gain cancellation block repetitive control block 21E are shown in the figure. Figure 11 The display shows that it has the following characteristics: Figure 1 The simulation results shown, without the phase compensation control block, demonstrate that... Figure 10 Compared to Figure 11 The zero-phase feedback current I0 is reduced, and the suppression effect is improved, thus verifying the effectiveness of the control method.

[0103] In summary, the control method for an open-winding motor according to an embodiment of the present invention first acquires the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor at the current moment. Then, it acquires the historical zero-phase feedback current after N sampling times prior to the current cycle. Based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity, it acquires the zero-phase setpoint voltage of the motor. Based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage, it acquires the duty cycles of the first and second inverters. Finally, it controls the motor based on the duty cycles. Therefore, this method only requires storing the historical zero-phase feedback current within one cycle, eliminating the need for complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0104] Corresponding to the above embodiments, the present invention also proposes a computer-readable storage medium.

[0105] The computer-readable storage medium of this invention stores a control program for an open-winding motor, which, when executed by a processor, implements the steps of the above-described method.

[0106] According to the computer-readable storage medium of the present invention, based on the above-described control method for an open-winding motor, only the historical zero-phase feedback current from one cycle ago needs to be stored, without the need for complex and heavy-load data calculation processing, and can be implemented using a low-cost microcomputer.

[0107] Corresponding to the above embodiments, the present invention also proposes an open-winding motor.

[0108] like Figure 12 As shown, the open-winding motor of this embodiment of the invention may include: a three-phase winding 10, a first inverter 20, a second inverter 30, and a control device 40.

[0109] The three-phase winding 10 is connected at both ends to the first inverter 20 and the second inverter 30, respectively, and the first inverter 20 and the second inverter 30 share a DC bus. The control device 40 includes a memory 41 and a processor 42. The memory 41 stores a computer program, and the processor 42 executes the computer program to implement the steps of the above method.

[0110] According to the open-winding motor of the present invention, based on the above-described control method for the open-winding motor, it is only necessary to store the historical zero-phase feedback current from one cycle ago, without performing complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0111] Corresponding to the above embodiments, the present invention also proposes a control device for an open-winding motor.

[0112] like Figure 13 As shown, the control device for an open-winding motor according to an embodiment of the present invention includes a three-phase winding. The two ends of the three-phase winding are respectively connected to a first inverter and a second inverter. The first inverter and the second inverter share a DC bus. The device may include: an acquisition module 60, a PR control module 70, a duty cycle generation module 80, and a control module 90.

[0113] The acquisition module 60 acquires the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor. The PR control module 70 acquires the historical zero-phase feedback current after N sampling times prior to the current cycle, and acquires the zero-phase setpoint voltage of the motor based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity. The duty cycle generation module 80 acquires the duty cycle of the first inverter and the second inverter based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage. The control module 90 controls the motor based on the duty cycle.

[0114] It should be noted that for details not disclosed in the control device of the open-winding motor in the embodiments of the present invention, please refer to the details disclosed in the control method of the open-winding motor in the above embodiments of the present invention, which will not be repeated here.

[0115] According to an embodiment of the present invention, the control device for an open-winding motor acquires the current zero-phase setpoint current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor through an acquisition module. It acquires the historical zero-phase feedback current after N sampling times prior to the current cycle through a PR control module, and obtains the zero-phase setpoint voltage of the motor based on the zero-phase setpoint current, zero-phase feedback current, historical zero-phase feedback current, and feedback angular velocity. A duty cycle generation module obtains the duty cycles of the first and second inverters based on the zero-phase setpoint voltage, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage. The control module controls the motor based on the duty cycles. Therefore, this device only needs to store the historical zero-phase feedback current from one cycle ago, eliminating the need for complex and heavy-load data calculations, and can be implemented using a low-cost microcomputer.

[0116] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0117] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0118] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0119] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0120] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A control method for an open-winding motor, characterized in that, The motor includes a three-phase winding, with its two ends connected to a first inverter and a second inverter, respectively. The first inverter and the second inverter share a DC bus. The method includes: Obtain the zero-phase given current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage, and DC bus voltage of the motor at the current moment; Obtain the historical zero-phase feedback current after N sampling times before one cycle of the zero-phase feedback current, where N is a positive integer; The zero-phase given voltage of the motor is obtained based on the zero-phase given current, the zero-phase feedback current, the historical zero-phase feedback current, and the feedback angular velocity. The duty cycles of the first inverter and the second inverter are obtained based on the zero-phase given voltage, the rotor position angle, the q-axis voltage, the d-axis voltage, and the DC bus voltage. The motor is controlled according to the duty cycle.

2. The method according to claim 1, characterized in that, The acquisition of the historical zero-phase feedback current after one cycle of sampling time N includes: The period of the zero-phase feedback current is obtained based on the feedback angular velocity; The N sampling time is obtained based on the sampling frequency of the zero-phase feedback current; The historical zero-phase feedback current is obtained from the historical database based on the time difference between the period and the N sampling time.

3. The method according to claim 2, characterized in that, The period of the zero-phase feedback current is three times the feedback angular velocity.

4. The method according to any one of claims 1-3, characterized in that, The step of obtaining the zero-phase given voltage of the motor based on the zero-phase given current, the zero-phase feedback current, the historical zero-phase feedback current, and the feedback angular velocity includes: A first voltage is obtained by performing a first proportional control on the current difference between the zero-phase given current and the zero-phase feedback current; The second voltage is obtained by resonant control of the current difference between the zero-phase given current and the historical zero-phase feedback current. The zero-phase given voltage is obtained by summing the first voltage and the second voltage.

5. The method according to claim 4, characterized in that, The step of obtaining a second voltage by resonant control of the current difference between the zero-phase given current and the historical zero-phase feedback current includes: The third voltage is obtained by performing a second proportional control on the current difference between the zero-phase given current and the historical zero-phase feedback current. The fourth voltage is obtained by integrating the product of the square of three times the feedback angular velocity and the second voltage at the previous moment. The second voltage at the current moment is obtained by integral control of the voltage difference between the third voltage and the fourth voltage.

6. The method according to claim 5, characterized in that, The method further includes: When the motor speed is determined to be greater than the preset speed based on the feedback angular velocity, the second voltage is obtained by resonant control of the current difference between the zero-phase given current and the historical zero-phase feedback current. When the motor speed is determined to be less than or equal to the preset speed based on the feedback angular velocity, the second voltage is obtained by resonant control of the current difference between the zero-phase given current and the zero-phase feedback current.

7. The method according to claim 1, characterized in that, The following information is obtained: the zero-phase feedback current, feedback angular velocity, and rotor position angle of the motor at the current moment. Obtain the three-phase current of the motor; The coordinate transformation of the three-phase current is used to obtain the q-axis feedback current, d-axis feedback current and zero-phase feedback current of the motor; The feedback angular velocity and the rotor position angle are obtained by position estimation based on the q-axis feedback current and the d-axis feedback current.

8. The method according to claim 7, characterized in that, Obtaining the q-axis voltage and d-axis voltage of the motor at the current moment includes: Obtain the given angular velocity and dq-axis voltage of the motor; The q-axis given current of the motor is obtained by speed control based on the angular velocity difference between the given angular velocity and the feedback angular velocity; The d-axis given current of the motor is obtained by applying field weakening control to the voltage difference between the DC bus voltage and the dq axis voltage. The q-axis voltage and the d-axis voltage are obtained by current control based on the given q-axis current, the given d-axis current, the q-axis feedback current, and the d-axis feedback current.

9. A computer-readable storage medium, characterized in that, It stores a control program for an open-winding motor, which, when executed by a processor, implements the steps of the method described in any one of claims 1 to 8.

10. An open-winding motor, characterized in that, include: The system comprises a three-phase winding, a first inverter, a second inverter, and a control device. The two ends of the three-phase winding are respectively connected to the first inverter and the second inverter, and the first inverter and the second inverter share a DC bus; The control device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 8.

11. A control device for an open-winding motor, characterized in that, The motor includes a three-phase winding, with its two ends connected to a first inverter and a second inverter, respectively. The first inverter and the second inverter share a DC bus. The device includes: The acquisition module is used to acquire the zero-phase given current, zero-phase feedback current, feedback angular velocity, rotor position angle, q-axis voltage, d-axis voltage and DC bus voltage of the motor at the current moment; The PR control module is used to acquire the historical zero-phase feedback current after N sampling times before one cycle of the zero-phase feedback current, and to acquire the zero-phase given voltage of the motor based on the zero-phase given current, the zero-phase feedback current, the historical zero-phase feedback current and the feedback angular velocity. The duty cycle generation module is used to obtain the duty cycle of the first inverter and the second inverter based on the zero-phase given voltage, the rotor position angle, the q-axis voltage, the d-axis voltage and the DC bus voltage; The control module is used to control the motor according to the duty cycle.

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