Permanent magnet synchronous motor parameter-free current prediction control method and device based on ANPC three-level inverter driving

Abstract

The invention provides a permanent magnet synchronous motor parameter-free current prediction control method and device based on ANPC three-level inverter driving. The method comprises the following steps: acquiring a voltage vector of the ANPC three-level inverter at a previous moment; a corresponding alternative voltage vector set is selected according to the voltage vector at the previous moment, and the number of basic voltage vectors in the alternative voltage vector set is smaller than 27; based on a cost function, selecting a basic voltage vector which enables the value of the cost function to be minimum from the alternative voltage vector set as an optimal basic voltage vector; and transmitting the on-off state corresponding to the optimal basic voltage vector to the ANPC three-level inverter so as to realize operation control of the permanent magnet synchronous motor. According to the technical scheme, the calculation burden of the system is reduced under the condition that the motor rotating speed control precision and the neutral-point voltage control precision are ensured.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a parameterless current prediction control method and device for a permanent magnet synchronous motor driven by an ANPC three-level inverter. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in industrial drives, aerospace, and electric vehicles due to their simple structure, high efficiency, and high power density. The active neutral point clamped (ANPC) three-level inverter topology is well-developed and offers advantages such as high power density, suitability for high DC bus voltage systems, and higher output waveform quality. The application of ANPC three-level inverters in the control of permanent magnet synchronous motors, especially in the control and speed regulation of high-voltage AC motors, is of great significance.

[0003] As voltage levels increase, the number of voltage vectors in the Space Vector Pulse Width Modulation (SVPWM) algorithm increases exponentially. A three-level inverter has 27 basic voltage vectors, making the partitioning and timing calculation of these space vectors increasingly complex. The ANPC three-level inverter also suffers from DC-side midpoint voltage imbalance, requiring additional algorithmic control. Model Predictive Control (MPC), on the other hand, offers advantages such as simple control and good dynamic performance, and can simultaneously control multiple objectives within the inverter using a cost function.

[0004] Since the ANPC three-level inverter has 27 basic voltage vectors, traversing all of them would greatly increase the computational burden and affect the dynamic performance of the control system. Moreover, traditional MPC relies on accurate mathematical models of the motor, while the nonlinear and multivariable properties of permanent magnet synchronous motors mean that system parameters will change during operation, leading to a decline in control performance. Summary of the Invention

[0005] In view of this, this application proposes a parameterless current prediction control method and device for permanent magnet synchronous motor driven by an ANPC three-level inverter.

[0006] Specifically, this application is implemented through the following technical solution: According to a first aspect of the embodiments of this specification, a parameterless current prediction control method for a permanent magnet synchronous motor driven by an ANPC three-level inverter is provided, comprising the following steps: Step S1: Obtain the voltage vector of the ANPC three-level inverter at the previous moment; Step S2: Select a corresponding set of candidate voltage vectors based on the voltage vector at the previous moment. The number of basic voltage vectors in the set of candidate voltage vectors is less than 27. Step S3: Select the basic voltage vector that minimizes the cost function from the set of candidate voltage vectors based on the cost function as the optimal basic voltage vector; Step S4: The switching state corresponding to the optimal basic voltage vector is sent to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

[0007] According to a second aspect of the embodiments of this specification, a parameterless current prediction control device for a permanent magnet synchronous motor driven by an ANPC three-level inverter is provided, the device comprising: The voltage vector acquisition unit is used to acquire the voltage vector of the ANPC three-level inverter at the previous moment; A voltage vector set selection unit is used to select a corresponding candidate voltage vector set based on the voltage vector at the previous moment, wherein the number of basic voltage vectors in the candidate voltage vector set is less than 27. An optimal voltage vector selection unit is used to select, based on a cost function, the basic voltage vector that minimizes the value of the cost function from the set of candidate voltage vectors as the optimal basic voltage vector. The motor control unit is used to transmit the switching state corresponding to the optimal basic voltage vector to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

[0008] According to a third aspect of the embodiments of this specification, an electronic device is provided, including a processor; and a computer-readable storage medium storing computer program instructions that, when executed by the processor, cause the processor to perform the method described in the first aspect.

[0009] According to a fourth aspect of the embodiments of this specification, a computer-readable storage medium is provided having a computer program stored thereon, the computer program being executed by a processor of the method described in the first aspect.

[0010] In this embodiment, a candidate voltage vector set is selected according to specific rules instead of traversing all 27 basic voltage vectors, which reduces the computational burden of the system. The optimal basic voltage vector is selected from the candidate voltage vector set based on the cost function, thereby improving the motor control effect. Attached Figure Description

[0011] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Some specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings indicate the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart illustrating an exemplary embodiment of the present application of a parameterless current prediction control method for a permanent magnet synchronous motor driven by an ANPC three-level inverter. Figure 2 This is a schematic diagram of a control system architecture shown in an exemplary embodiment of this application; Figure 3 This is a schematic diagram of the topology of an ANPC three-level inverter shown in an exemplary embodiment of this application; Figure 4 This is a schematic diagram of the space voltage vector of an ANPC three-level inverter, as illustrated in an exemplary embodiment of this application. Figure 5 This is a schematic diagram of a motor speed waveform shown in an exemplary embodiment of this application; Figure 6 This is a schematic diagram of the DC side midpoint voltage deviation of an ANPC three-level inverter, as shown in an exemplary embodiment of this application. Figure 7 This is a block diagram illustrating an electronic device according to an exemplary embodiment of this application; Figure 8 This is a block diagram of a parameterless current prediction control device for a permanent magnet synchronous motor driven by an ANPC three-level inverter, as illustrated in an exemplary embodiment of this application. Detailed Implementation

[0012] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0013] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0014] The embodiments described in this specification will now be described in detail.

[0015] This application provides a parameterless current prediction control method for a permanent magnet synchronous motor driven by an ANPC three-level inverter. Figure 1 This is a schematic flowchart illustrating a parameterless current prediction control method for a permanent magnet synchronous motor driven by an ANPC three-level inverter, as shown in an exemplary embodiment of this application. Figure 1 As shown, the control method includes at least the following steps: Step S1: Obtain the voltage vector of the ANPC three-level inverter at the previous moment.

[0016] Step S2: Select a corresponding set of candidate voltage vectors based on the voltage vector at the previous moment. The number of basic voltage vectors in the set of candidate voltage vectors is less than 27. Step S3: Select the basic voltage vector that minimizes the cost function from the set of candidate voltage vectors based on the cost function as the optimal basic voltage vector; Step S4: The switching state corresponding to the optimal basic voltage vector is sent to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

[0017] In some embodiments, the control method further includes: Based on the switching rules of the ANPC three-level inverter, the correspondence between the voltage vector of the ANPC three-level inverter at the previous moment and the set of candidate voltage vectors at the next moment is established in advance. Step S2 includes: determining a set of candidate voltage vectors corresponding to the voltage vector at the previous moment based on the correspondence; The switching rules are as follows: The switching state P of the ANPC three-level inverter remains in the current switching state P or changes to the switching state O in the next moment. The switching state N of the ANPC three-level inverter will either maintain the current switching state N or change to the switching state O in the next moment. The switching state O of the ANPC three-level inverter remains in the current switching state O or changes to the switching state P or N in the next moment.

[0018] In other words, switch state P cannot directly change to switch state N, and switch state N cannot directly change to switch state P.

[0019] Specifically, the correspondence between the voltage vector of the previous moment and the set of candidate voltage vectors for the next moment includes: If the voltage vector at the previous moment is PPP, then the corresponding set of candidate voltage vectors is PPP, OPP, POP, PPO; If the voltage vector at the previous moment is PPO, then the corresponding set of candidate voltage vectors is PPO, OPO, POO, PPP, PPN; If the voltage vector at the previous moment is PPN, then the corresponding set of candidate voltage vectors is PPN, OPN, PON, PPO; If the voltage vector at the previous moment is POP, then the corresponding set of candidate voltage vectors is POP, OOP, PPP, PNP, POO; If the voltage vector at the previous moment is POO, then the corresponding set of candidate voltage vectors is POO, OOO, PPO, PNO, POP, PON; If the voltage vector at the previous moment is PON, then the corresponding set of candidate voltage vectors is PON, OON, PPN, PNN, POO; If the voltage vector at the previous moment is PNP, then the corresponding set of candidate voltage vectors is PNP, ONP, POP, PNO; If the voltage vector at the previous moment is PNO, then the corresponding candidate voltage vector set is PNO, ONO, POO, PNP, PNN; If the voltage vector at the previous moment is PNN, then the corresponding set of candidate voltage vectors is PNN, ONN, PON, PNO; If the voltage vector at the previous moment is OPP, then the corresponding set of candidate voltage vectors is OPP, PPP, NPP, OOP, OPO; If the voltage vector at the previous moment is OPO, then the corresponding set of candidate voltage vectors is OPO, PPO, NPO, OOO, OPP, OPN; If the voltage vector at the previous moment is OPN, then the corresponding set of candidate voltage vectors is OPN, PPN, NPN, OON, OPO; If the voltage vector at the previous moment is OOP, then the corresponding set of candidate voltage vectors is OOP, POP, NOP, OPP, ONP, OOO; If the voltage vector at the previous moment is OOO, then the corresponding set of candidate voltage vectors is OOO, POO, NOO, OPO, ONO, OOP, OON; If the voltage vector at the previous moment is OON, then the corresponding set of candidate voltage vectors is OON, PON, NON, OPN, ONN, OOO; If the voltage vector at the previous moment is ONP, then the corresponding set of candidate voltage vectors is ONP, PNP, NNP, OOP, ONO; If the voltage vector at the previous moment is ONO, then the corresponding set of candidate voltage vectors is ONO, PNO, NNO, OOO, ONP, ONN; If the voltage vector at the previous moment is ONN, then the corresponding set of candidate voltage vectors is ONN, PNN, NNN, OON, ONO; If the voltage vector at the previous moment is NPP, then the corresponding set of candidate voltage vectors is NPP, OPP, NOP, NPO; If the voltage vector at the previous moment is NPO, then the corresponding set of candidate voltage vectors is NPO, OPO, NOO, NPP, NPN; If the voltage vector at the previous moment is NPN, then the corresponding set of candidate voltage vectors is NPN, OPN, NON, NPO; If the voltage vector at the previous moment is NOP, then the corresponding set of candidate voltage vectors is NOP, OOP, NPP, NNP, NOO; If the voltage vector at the previous moment is NOO, then the corresponding set of candidate voltage vectors is NOO, OOO, NPO, NNO, NOP, NON; If the voltage vector at the previous moment is NON, then the corresponding set of candidate voltage vectors is NON, OON, NPN, NNN, NOO; If the voltage vector at the previous moment is NNP, then the corresponding set of candidate voltage vectors is NNP, ONP, NOP, NNO; If the voltage vector at the previous moment is NNO, then the corresponding set of candidate voltage vectors is NNO, ONO, NOO, NNP, NNN; If the voltage vector at the previous moment is NNN, then the corresponding set of candidate voltage vectors is NNN, ONN, NON, NNO.

[0020] In some embodiments, step S3 includes: The following steps are taken: First, obtain the d-axis and q-axis voltages generated by different voltage vectors in the candidate voltage vector set, as well as the d-axis and q-axis currents sampled at the current moment. Based on a pre-built permanent magnet synchronous motor model, obtain the predicted values ​​of the d-axis and q-axis currents for the next moment. Second, obtain the three-phase bridge arm output switch states corresponding to each basic voltage vector in the candidate voltage vector set, the three-phase currents sampled at the current moment, and the midpoint voltage deviation sampled at the current moment. Based on a pre-established midpoint voltage deviation prediction model, obtain the predicted value of the midpoint voltage deviation for the next moment. Third, based on the predicted values ​​of the d-axis and q-axis currents, the predicted value of the midpoint voltage deviation for the next moment, and the pre-set reference values ​​of the d-axis and q-axis currents, calculate the cost function values ​​corresponding to all basic voltage vectors in the candidate voltage vector set. Finally, select the basic voltage vector with the smallest cost function value as the optimal basic voltage vector.

[0021] In some embodiments, the permanent magnet synchronous motor model is: in, , , , , For the first The d-axis current obtained by sampling at each time step For the first The q-axis current obtained by sampling at any given time. For the first The predicted d-axis current value at time t. For the first The predicted q-axis current at time t is 1. For the first The rotor's electric angular velocity at all times, For the first The selected d-axis stator voltage at that moment For the first The q-axis stator voltage selected at that moment. For stator resistance, It is a permanent magnet flux linkage. To control the cycle, For d-axis inductance, It is the q-axis inductance.

[0022] In some embodiments, the midpoint voltage deviation prediction model is: in, For the first Midpoint voltage deviation at time t. For the first Midpoint voltage deviation at time, , , The first The three-phase currents (A, B, and C) obtained by sampling at various times. , , This refers to the output switch status of the three-phase bridge arm. The capacitance is either the upper DC-side capacitor or the lower DC-side capacitor, wherein the upper DC-side capacitor capacitance is equal to the lower DC-side capacitor capacitance.

[0023] In some embodiments, the cost function for: in, For the first The reference value of the d-axis current at time t. For the first The q-axis current reference value at time t. , , These are the preset weighting coefficients.

[0024] Next, with Figure 2 The aforementioned control system and Figure 3 Taking the ANPC three-level inverter shown as an example, the control process of the embodiments of this application will be described in detail.

[0025] First, a permanent magnet synchronous motor model independent of motor parameters is established.

[0026] The traditional voltage equation for a permanent magnet synchronous motor is: (1) In formula (1), , These are the d-axis stator voltage and the q-axis stator voltage, respectively. Stator resistance; , These are the d-axis stator current and the q-axis stator current, respectively. , These are the d-axis inductance and the q-axis inductance, respectively. For permanent magnet flux linkage; Electric angular velocity; For time.

[0027] To obtain a discretized prediction model suitable for FCS-MPC (Finite Control Set-Model Predictive Control), the forward Euler method is used: (2) Discretizing formula (1) allows us to obtain the result on the 1st... Predicting the first time the permanent magnet synchronous motor generates under any voltage vector. If the current is at a given time, then the current prediction model is: (3) In formula (3), To control the cycle, For the first The predicted d-axis current value at time t. For the first The predicted q-axis current at time t is 1. For the first The d-axis current obtained by sampling at each time step For the first The q-axis current obtained by sampling at any given time. For the first The rotor's electric angular velocity at all times, For the first The selected d-axis stator voltage at that moment For the first The q-axis stator voltage selected at that moment.

[0028] Simplifying formula (3) to highlight the mathematical relationship between voltage and current increments, we obtain the permanent magnet synchronous motor model as follows: (4) In formula (4), , .

[0029] Next, the recursive least squares method is used to identify the permanent magnet synchronous motor model. and .

[0030] Construct recursive least squares equations, using Indicates the first The value of this quantity at any given time, taking the d-axis as an example: (5) In formula (5), Here is the gain matrix. Let covariance matrix be the variance matrix. Forgetting factor, It is the identity matrix. For the current increment matrix, the parameters are... , , Simplify the model parameters for the d-axis to be identified.

[0031] Identifying the parameters of the simplified q-axis model The process of identifying simplified d-axis model parameters The process is similar, and will not be described in detail here.

[0032] Then, a prediction model for the midpoint voltage deviation of the ANPC three-level inverter is established.

[0033] The ANPC three-level inverter topology in this embodiment is as follows: Figure 3 As shown, the switching state function of the ANPC three-level inverter is: (6) In formula (6), , , This refers to the output switching state of the three-phase bridge arm. Taking phase A as an example, when... When, it represents the output state as P, when When, it represents the output state as 0. When , it represents the output state as N.

[0034] The mathematical model of the DC side of the ANPC three-level inverter is: (7) In formula (7), This refers to the current of the capacitor on the DC side. This refers to the current of the capacitor on the DC side. This is the voltage across the capacitor on the DC side. This is the voltage of the capacitor on the DC side. This refers to either the upper or lower capacitance of the DC-side capacitor, where the upper and lower capacitances are equal. This is the DC side midpoint current. , , These are the three-phase currents, A, B, and C, respectively.

[0035] Using the forward Euler method to discretize formula (7), the discretized DC-side mathematical model of the ANPC three-level inverter is as follows: (8) In formula (8), For the first The current of the capacitor on the DC side at any given time. For the first DC side capacitor current at all times For the first At any given moment, the voltage of the capacitor on the DC side, For the first At any given moment, the voltage of the capacitor on the DC side, For the first The DC-side capacitor voltage at any given moment. For the first The DC-side capacitor voltage at any given moment. For the first DC side midpoint current at constant time , , The first The three-phase currents A, B, and C obtained by sampling at any time.

[0036] Based on formula (8), the midpoint voltage deviation prediction model can be obtained: (9) In formula (9), , For the first At time 1, the voltage of the capacitor on the DC side is the same as the voltage at the 1st moment. The difference in the DC-side capacitor voltage at time t, i.e., the first... Midpoint voltage deviation at any given time; For the first At time 1, the voltage of the capacitor on the DC side is the same as the voltage at the 1st moment. The difference in the DC-side capacitor voltage at time t, i.e., the first... Voltage deviation at midpoint at any given time.

[0037] Next, based on the voltage vector output at the previous moment, select the corresponding set of candidate voltage vectors: like Figure 4 As shown, the ANPC three-level inverter has 27 basic voltage vectors. Since traversing all 27 basic voltage vectors at once would increase the computational burden, this embodiment pre-establishes a set of candidate voltage vectors according to the following switching rules. The switching rules are as follows: based on the voltage vector at the previous moment, only one phase of the candidate voltage vector at the next moment can change its switching state, or all three phases can remain unchanged. Furthermore, the rules for changing the switching state are: P can change to O, N can change to O, O can change to P or N, but P cannot directly change to N, and N cannot directly change to P. In this way, the correspondence between the voltage vector at the previous moment and the set of candidate voltage vectors at the next moment, as described above, can be obtained.

[0038] It is worth noting that the initial output voltage vector is set to OOO.

[0039] This embodiment is based on Figure 2 The MPC component in the control system shown calculates the voltage vector of the ANPC three-level inverter. The specific calculation process can be found in relevant technical solutions for those skilled in the art, and will not be described in this embodiment. Thus, the MPC component can obtain the voltage vector of the ANPC three-level inverter at the previous moment, and based on the above correspondence, a corresponding set of candidate voltage vectors can be selected.

[0040] Finally, the cost function is used to select the basic voltage vector that provides the best centralized control effect among the candidate voltage vectors.

[0041] The simplified model parameters of the d-axis will be identified. Simplified model parameters with the q-axis The d-axis voltage generated by different voltage vectors in the selected candidate voltage vector set. With q-axis voltage and the d-axis current obtained by sampling at time 10 pm With q-axis current Substituting these values ​​into equation (4), we obtain the d-axis current increment and the q-axis current increment, thus obtaining the first... d-axis current prediction at time 1 Compared with the predicted q-axis current .

[0042] The different voltage vectors in the selected candidate voltage vector set are matched one-to-one with the different voltage vectors according to formula (6). , , , No. The three-phase currents (A, B, and C) obtained by sampling at different times , , and the Midpoint voltage deviation obtained from sampling at various times Simultaneously, substituting into formula (9), the midpoint voltage deviation is predicted, and the first... Midpoint voltage deviation prediction at time 1 .

[0043] For example, the cost function in this embodiment is: (10) In formula (10), , The first The d-axis current reference value and q-axis current reference value at time t. , , These are the preset weighting coefficients.

[0044] Iterate through all the basic voltage vectors in the selected candidate voltage vector set, and select the one that minimizes the cost function as the first... The optimal basic voltage vector at any given time is determined, and the switching state of this optimal basic voltage vector is transmitted to the ANPC three-level inverter to realize the control operation of the permanent magnet synchronous motor and the DC side midpoint voltage control of the ANPC three-level inverter.

[0045] This application also includes simulation experiments, where the simulation parameters for the permanent magnet synchronous motor are set as follows: stator resistance. dq axis inductance Number of magnetic pole pairs Permanent magnet flux Moment of inertia DC bus voltage The speed of the permanent magnet synchronous motor is set to change from an initial 800 rpm to 1600 rpm in 0.3 seconds. Figure 5 This is the motor speed waveform. Figure 6 This refers to the DC-side midpoint voltage deviation of the ANPC three-level inverter. Figure 5 and Figure 6 As can be seen from the embodiments of this application, the control method has better motor speed control accuracy and better midpoint voltage control accuracy.

[0046] Based on the above embodiments of this application, the technical solution of this application has at least the following technical effects: (1) The embodiments of this application construct a permanent magnet synchronous motor model that does not involve specific motor parameters, and use the recursive least squares method with forgetting factor to identify the permanent magnet synchronous motor model parameters. The identification speed is fast and the accuracy is high, avoiding the impact of motor parameter mismatch and improving the robustness of the system. (2) The embodiments of this application select the candidate voltage vector set according to specific rules, reducing the number of candidate voltage vectors to 4-7, without having to traverse all 27 basic voltage vectors, thus reducing the computational burden of the system.

[0047] Figure 7 This is a schematic diagram of an electronic device illustrated in this specification according to an exemplary embodiment. Please refer to... Figure 7 At the hardware level, the device includes a processor 702, an internal bus 704, a network interface 706, memory 708, a hardware acceleration device 710, and non-volatile memory 712, and may also include other hardware required for its functions. One or more embodiments of this application can be implemented in software, for example, the processor 702 reads the corresponding computer program from the non-volatile memory 712 into the memory 708 and then runs it. Of course, in addition to software implementation, one or more embodiments of this application do not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. That is to say, the execution subject of the above processing flow is not limited to each logic unit, but can also be hardware or logic devices.

[0048] Figure 8 This is a block diagram illustrating a parameterless current prediction control device for a permanent magnet synchronous motor driven by an ANPC three-level inverter, as shown in an exemplary embodiment of this application. The control device can be applied to applications such as... Figure 8The electronic device shown implements the technical solution of this application. The control device includes: a voltage vector acquisition unit 810, a vector set selection unit 820, an optimal voltage selection unit 830, and a motor control unit 840, wherein: The voltage vector acquisition unit 810 is used to acquire the voltage vector of the ANPC three-level inverter at the previous moment; The voltage vector set selection unit 820 is used to select a corresponding candidate voltage vector set based on the voltage vector at the previous moment, wherein the number of basic voltage vectors in the candidate voltage vector set is less than 27. The optimal voltage vector selection unit 830 is used to select the basic voltage vector that minimizes the value of the cost function from the set of candidate voltage vectors based on the cost function as the optimal basic voltage vector. The motor control unit 840 is used to transmit the switching state corresponding to the optimal basic voltage vector to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

[0049] In some embodiments, the control device further includes: The preprocessing unit is used to establish the correspondence between the voltage vector of the ANPC three-level inverter at the previous moment and the set of candidate voltage vectors at the next moment, based on the switching rules of the ANPC three-level inverter. The voltage vector set selection unit 820 is specifically used to determine a set of candidate voltage vectors corresponding to the voltage vector at the previous moment based on the correspondence relationship. The switching rules are as follows: compared to the voltage vector at the previous moment, the voltage vector at the next moment can only change the switching state of one phase or all three phases remain unchanged, and the following state change constraints are satisfied: the switching state P of the ANPC three-level inverter maintains the current switching state P or changes to the switching state O at the next moment; the switching state N of the ANPC three-level inverter maintains the current switching state N or changes to the switching state O at the next moment; the switching state O of the ANPC three-level inverter maintains the current switching state O or changes to the switching state P or N at the next moment.

[0050] In some embodiments, the optimal voltage selection unit 830 is used to acquire the d-axis voltage and q-axis voltage generated by different voltage vectors in the candidate voltage vector set, as well as the d-axis current and q-axis current sampled at the current moment, so as to obtain the predicted values ​​of the d-axis current and q-axis current at the next moment based on a pre-built permanent magnet synchronous motor model; acquire the three-phase bridge arm output switch state corresponding to each basic voltage vector in the candidate voltage vector set, the three-phase current sampled at the current moment, and the midpoint voltage deviation sampled at the current moment, so as to obtain the predicted value of the midpoint voltage deviation at the next moment based on a pre-established midpoint voltage deviation prediction model; calculate the value of the cost function corresponding to all basic voltage vectors in the candidate voltage vector set based on the predicted values ​​of the d-axis current and q-axis current at the next moment, the predicted value of the midpoint voltage deviation at the next moment, and the pre-set reference values ​​of the d-axis current and q-axis current; and select the basic voltage vector with the smallest cost function value as the optimal basic voltage vector.

[0051] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0052] Accordingly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the methods described in any of the above embodiments.

[0053] Accordingly, embodiments of this application also provide a computer program product configured to perform the methods described in any of the above embodiments.

[0054] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which can take the form of a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email sending and receiving device, game console, tablet computer, wearable device, or any combination of these devices.

[0055] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0056] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0057] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random-access memory (SRAM), dynamic random-access memory (DRAM), other types of random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0058] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily intended to describe features of specific embodiments of a particular invention. Certain features described in the various embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation thereof.

[0059] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0060] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings are not necessarily shown in a specific order or sequence to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0061] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A parameterless current prediction control method for a permanent magnet synchronous motor driven by an ANPC three-level inverter, characterized in that, Includes the following steps: Step S1: Obtain the voltage vector of the ANPC three-level inverter at the previous moment; Step S2: Select a corresponding set of candidate voltage vectors based on the voltage vector at the previous moment. The number of basic voltage vectors in the set of candidate voltage vectors is less than 27. Step S3: Select the basic voltage vector that minimizes the cost function from the set of candidate voltage vectors based on the cost function as the optimal basic voltage vector; Step S4: The switching state corresponding to the optimal basic voltage vector is sent to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

2. The method according to claim 1, characterized in that, The method further includes: Based on the switching rules of the ANPC three-level inverter, the correspondence between the voltage vector of the ANPC three-level inverter at the previous moment and the set of candidate voltage vectors at the next moment is established in advance. Step S2 includes: determining a set of candidate voltage vectors corresponding to the voltage vector at the previous moment based on the correspondence; The switching rule is as follows: compared to the voltage vector at the previous moment, the voltage vector at the next moment can change the switching state of only one phase or all three phases remain unchanged, and the following state change constraint conditions are satisfied: The switching state P of the ANPC three-level inverter remains in the current switching state P or changes to the switching state O in the next moment. The switching state N of the ANPC three-level inverter will either maintain the current switching state N or change to the switching state O in the next moment. The switching state O of the ANPC three-level inverter remains in the current switching state O or changes to the switching state P or N in the next moment.

3. The method according to claim 2, characterized in that, The correspondence between the voltage vector at the previous moment and the set of candidate voltage vectors at the next moment includes: If the voltage vector at the previous moment is PPP, then the corresponding set of candidate voltage vectors is PPP, OPP, POP, PPO; If the voltage vector at the previous moment is PPO, then the corresponding set of candidate voltage vectors is PPO, OPO, POO, PPP, PPN; If the voltage vector at the previous moment is PPN, then the corresponding set of candidate voltage vectors is PPN, OPN, PON, PPO; If the voltage vector at the previous moment is POP, then the corresponding set of candidate voltage vectors is POP, OOP, PPP, PNP, POO; If the voltage vector at the previous moment is POO, then the corresponding set of candidate voltage vectors is POO, OOO, PPO, PNO, POP, PON; If the voltage vector at the previous moment is PON, then the corresponding set of candidate voltage vectors is PON, OON, PPN, PNN, POO; If the voltage vector at the previous moment is PNP, then the corresponding set of candidate voltage vectors is PNP, ONP, POP, PNO; If the voltage vector at the previous moment is PNO, then the corresponding candidate voltage vector set is PNO, ONO, POO, PNP, PNN; If the voltage vector at the previous moment is PNN, then the corresponding set of candidate voltage vectors is PNN, ONN, PON, PNO; If the voltage vector at the previous moment is OPP, then the corresponding set of candidate voltage vectors is OPP, PPP, NPP, OOP, OPO; If the voltage vector at the previous moment is OPO, then the corresponding set of candidate voltage vectors is OPO, PPO, NPO, OOO, OPP, OPN; If the voltage vector at the previous moment is OPN, then the corresponding set of candidate voltage vectors is OPN, PPN, NPN, OON, OPO; If the voltage vector at the previous moment is OOP, then the corresponding set of candidate voltage vectors is OOP, POP, NOP, OPP, ONP, OOO; If the voltage vector at the previous moment is OOO, then the corresponding set of candidate voltage vectors is OOO, POO, NOO, OPO, ONO, OOP, OON; If the voltage vector at the previous moment is OON, then the corresponding set of candidate voltage vectors is OON, PON, NON, OPN, ONN, OOO; If the voltage vector at the previous moment is ONP, then the corresponding set of candidate voltage vectors is ONP, PNP, NNP, OOP, ONO; If the voltage vector at the previous moment is ONO, then the corresponding set of candidate voltage vectors is ONO, PNO, NNO, OOO, ONP, ONN; If the voltage vector at the previous moment is ONN, then the corresponding set of candidate voltage vectors is ONN, PNN, NNN, OON, ONO; If the voltage vector at the previous moment is NPP, then the corresponding set of candidate voltage vectors is NPP, OPP, NOP, NPO; If the voltage vector at the previous moment is NPO, then the corresponding set of candidate voltage vectors is NPO, OPO, NOO, NPP, NPN; If the voltage vector at the previous moment is NPN, then the corresponding set of candidate voltage vectors is NPN, OPN, NON, NPO; If the voltage vector at the previous moment is NOP, then the corresponding set of candidate voltage vectors is NOP, OOP, NPP, NNP, NOO; If the voltage vector at the previous moment is NOO, then the corresponding set of candidate voltage vectors is NOO, OOO, NPO, NNO, NOP, NON; If the voltage vector at the previous moment is NON, then the corresponding set of candidate voltage vectors is NON, OON, NPN, NNN, NOO; If the voltage vector at the previous moment is NNP, then the corresponding set of candidate voltage vectors is NNP, ONP, NOP, NNO; If the voltage vector at the previous moment is NNO, then the corresponding set of candidate voltage vectors is NNO, ONO, NOO, NNP, NNN; If the voltage vector at the previous moment is NNN, then the corresponding set of candidate voltage vectors is NNN, ONN, NON, NNO.

4. The method according to claim 1, characterized in that, Step S3 includes: The d-axis voltage and q-axis voltage generated by different voltage vectors in the candidate voltage vector set, as well as the d-axis current and q-axis current sampled at the current moment, are obtained to obtain the predicted values ​​of the d-axis current and q-axis current at the next moment based on the pre-built permanent magnet synchronous motor model. The three-phase bridge arm output switch state corresponding to each basic voltage vector in the candidate voltage vector set, the three-phase current sampled at the current moment, and the midpoint voltage deviation sampled at the current moment are obtained, so as to obtain the predicted value of the midpoint voltage deviation at the next moment based on the pre-established midpoint voltage deviation prediction model. Based on the predicted d-axis current and q-axis current values ​​at the next time step, the predicted midpoint voltage deviation at the next time step, and the pre-set reference values ​​for d-axis current and q-axis current, calculate the cost function values ​​corresponding to all basic voltage vectors in the candidate voltage vector set. The basic voltage vector that minimizes the cost function is taken as the optimal basic voltage vector.

5. The method according to claim 4, characterized in that, The permanent magnet synchronous motor model is as follows: in, , , , , For the first The d-axis current obtained by sampling at each time step For the first The q-axis current obtained by sampling at any given time. For the first The predicted d-axis current value at time t. For the first The predicted q-axis current at time t is 1. For the first The rotor's electric angular velocity at all times, For the first The selected d-axis stator voltage at that moment For the first The q-axis stator voltage selected at that moment. For stator resistance, It is a permanent magnet flux linkage. To control the cycle, For d-axis inductance, It is the q-axis inductance.

6. The method according to claim 5, characterized in that, The midpoint voltage deviation prediction model is as follows: in, For the first Midpoint voltage deviation at time t. For the first Midpoint voltage deviation at time, , , The first The three-phase currents (A, B, and C) obtained by sampling at various times. , , This refers to the output switch status of the three-phase bridge arm. The capacitance is either the upper DC-side capacitor or the lower DC-side capacitor, wherein the upper DC-side capacitor capacitance is equal to the lower DC-side capacitor capacitance.

7. The method according to claim 6, characterized in that, The cost function for: in, For the first The reference value of the d-axis current at time t. For the first The q-axis current reference value at time t. , , These are the preset weighting coefficients.

8. A parameterless current prediction control device for a permanent magnet synchronous motor driven by an ANPC three-level inverter, characterized in that, The device includes: The voltage vector acquisition unit is used to acquire the voltage vector of the ANPC three-level inverter at the previous moment; A voltage vector set selection unit is used to select a corresponding candidate voltage vector set based on the voltage vector at the previous moment, wherein the number of basic voltage vectors in the candidate voltage vector set is less than 27. An optimal voltage vector selection unit is used to select, based on a cost function, the basic voltage vector that minimizes the value of the cost function from the set of candidate voltage vectors as the optimal basic voltage vector. The motor control unit is used to transmit the switching state corresponding to the optimal basic voltage vector to the ANPC three-level inverter to realize the operation control of the permanent magnet synchronous motor.

9. An electronic device, characterized in that, include: processor; as well as A computer-readable storage medium storing computer program instructions that, when executed by the processor, cause the processor to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which is executed by a processor according to any one of claims 1 to 7.

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