A permanent magnet synchronous motor model predictive control method, device and driver

Abstract

This article provides a permanent magnet synchronous motor model predictive control method, device and driver, the method comprising: obtaining voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determining multiple alternative voltage modulation vectors based on the voltage vector, wherein the zero-sequence component of each alternative voltage vector is zero; collecting the operating parameters of the permanent magnet synchronous motor in the current control cycle; calculating the current prediction value corresponding to each alternative voltage modulation vector based on the operating parameters and a preset prediction model; obtaining a given current value, and determining a target current prediction value based on the given current value and multiple current prediction values; determining the alternative voltage modulation vector corresponding to the target current value as the target control voltage of the next control cycle to realize drive control of the permanent magnet synchronous motor. This article can avoid the influence of current harmonics caused by the zero-sequence component in the voltage vector, thereby improving the reliability and efficiency of motor control.

Description

Technical Field

[0001] This article belongs to the field of motor systems and control, and specifically relates to a permanent magnet synchronous motor model predictive control method, device and driver. Background Art

[0002] The traditional three-phase, three-leg main circuit topology employs voltage space vector modulation (SVPWM) technology to reduce the harmonic content of the winding current and improve the utilization of the DC bus voltage, thereby reducing motor torque ripple and widening the motor's speed regulation range. However, this traditional topology struggles to maintain safe and reliable system operation in the event of a phase loss or single-phase circuit breaker fault. Therefore, a three-phase, three-leg topology is created by adding an additional leg connected to the motor's neutral point. This topology also employs voltage space vector modulation technology to drive the permanent magnet synchronous motor.

[0003] SVPWM modulation technology cannot completely eliminate the effects of the zero-sequence voltage component of the voltage fundamental vector. Consequently, the zero-sequence current harmonics generated by this zero-sequence voltage component cause significant torque fluctuations, which in turn affect motor operation. Therefore, improving the control efficiency and performance of series-wound three-phase, four-leg permanent magnet synchronous motors has become a pressing technical challenge. Summary of the Invention

[0004] In view of the above problems in the prior art, the purpose of this paper is to provide a permanent magnet synchronous motor model predictive control method, device and driver to improve the control efficiency of a series-wound three-phase four-bridge-arm permanent magnet synchronous motor.

[0005] In order to solve the above technical problems, the specific technical solutions of this article are as follows:

[0006] In one aspect, this paper provides a model predictive control method for a permanent magnet synchronous motor, the method comprising:

[0007] Obtaining voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determining a plurality of candidate voltage modulation vectors based on the voltage vectors, wherein the zero-sequence component of each candidate voltage vector is zero;

[0008] Collect the operating parameters of the permanent magnet synchronous motor in the current control cycle;

[0009] Calculating a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model;

[0010] Obtaining a given current value, and determining a target current prediction value based on the given current value and a plurality of current prediction values;

[0011] The candidate voltage modulation vector corresponding to the target current value is determined as the target control voltage of the next control cycle to achieve drive control of the permanent magnet synchronous motor.

[0012] Furthermore, determining a plurality of candidate voltage modulation vectors according to the voltage vector includes:

[0013] Determine the three phase voltages corresponding to each voltage vector;

[0014] According to the three phase voltages, a zero-sequence component corresponding to each voltage vector is calculated;

[0015] A voltage vector having a zero-sequence component of zero is determined as a candidate voltage modulation vector.

[0016] Preferably, the calculating and obtaining the zero-sequence component corresponding to each voltage vector according to the three phase voltages includes:

[0017] An average value of the three phase voltages is calculated according to the three phase voltages, and the average value is used as a zero-sequence component corresponding to the voltage vector.

[0018] Furthermore, according to the operating parameters and the preset prediction model, a current prediction value corresponding to each candidate voltage modulation vector is calculated, including:

[0019] Acquiring the operating parameters, wherein the operating parameters include a three-phase stator current of the permanent magnet synchronous motor and a motor rotor position angle;

[0020] Converting the three-phase stator current into a direct-axis component and a quadrature-axis component of the stator current through coordinates, and obtaining the rotor electrical angular velocity through a differential process of the motor rotor position angle;

[0021] Converting the candidate voltage modulation vector into a direct-axis component and a quadrature-axis component of a voltage vector through coordinates;

[0022] According to the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, a current prediction value corresponding to each alternative voltage modulation vector is calculated through a preset prediction model.

[0023] Furthermore, the current prediction value corresponding to each candidate voltage modulation vector is calculated by a preset prediction model based on the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, including:

[0024] Setting the direct-axis component of the current prediction value to a specified value;

[0025] According to the specified value, combined with the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, the quadrature-axis prediction value of the current prediction value corresponding to each alternative voltage modulation vector is calculated through a preset prediction model.

[0026] Furthermore, obtaining a given current value includes:

[0027] Determine the target speed of the current control cycle;

[0028] A given current value is obtained through PI control according to the target rotational speed and the rotor electrical angular velocity.

[0029] Furthermore, the obtaining of a given current value and determining a target current prediction value based on the given current value and a plurality of current prediction values ​​includes:

[0030] Calculating an evaluation value of each current prediction value by using a cost function according to the given current value and the plurality of current prediction values;

[0031] The current prediction value with the smallest evaluation value is taken as the target current prediction value.

[0032] On the other hand, this article also provides a permanent magnet synchronous motor model predictive control device, the device comprising:

[0033] an alternative voltage modulation vector determination module, configured to obtain voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determine a plurality of alternative voltage modulation vectors based on the voltage vectors, wherein the zero-sequence component of each of the alternative voltage vectors is zero;

[0034] Working parameter acquisition module, used to collect the working parameters of the permanent magnet synchronous motor in the current control cycle;

[0035] a current prediction value calculation module, configured to calculate a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model;

[0036] a target current predicted value determination module, configured to obtain a given current value and determine a target current predicted value based on the given current value and a plurality of current predicted values;

[0037] A driving module is used to determine the candidate voltage modulation vector corresponding to the target current value as the target control voltage of the next control cycle to achieve drive control of the permanent magnet synchronous motor.

[0038] On the other hand, this document also provides a driver, the driver comprising: a memory and a controller;

[0039] The memory stores a computer program executable on the controller;

[0040] When the controller executes the computer program, the control method described above is implemented.

[0041] Finally, this article also provides a motor system, which includes a series-wound three-phase four-bridge-arm permanent magnet synchronous motor and the drive described above.

[0042] By adopting the above technical solution, a permanent magnet synchronous motor model predictive control method, device and driver described in this article determine the voltage vector with zero zero-sequence component from the voltage vectors corresponding to all the switching states of the permanent magnet synchronous motor, and use this voltage vector as an alternative voltage modulation vector. Then, through the collected working parameters and the preset prediction model, the current prediction value corresponding to each alternative voltage modulation vector is calculated, and the target current prediction value is determined according to the current prediction value and the given current value, and then the target control voltage for driving the motor in the next control cycle is determined. This article can avoid the influence of current harmonics caused by the zero-sequence component in the voltage vector and improve the reliability and efficiency of motor control.

[0043] In order to make the above and other purposes, features and advantages of this article more obvious and easy to understand, the following specifically cites preferred embodiments and provides detailed descriptions in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of this article or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of this article. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A schematic diagram of the steps of a permanent magnet synchronous motor model predictive control method provided in an embodiment of this invention is shown;

[0046] Figure 2 A schematic diagram showing steps for determining an alternative voltage debugging vector in an embodiment of this invention is shown;

[0047] Figure 3 A schematic diagram of the steps for calculating the current prediction value in the embodiment of this article is shown;

[0048] Figure 4 The topology diagram of the series-wound three-phase four-bridge-arm permanent magnet synchronous motor and inverter in the embodiment of this article is shown;

[0049] Figure 5 The embodiment of this article provides a schematic diagram of the model predictive control principle of a three-phase four-bridge-arm permanent magnet synchronous motor with a series winding;

[0050] Figure 6A schematic diagram of the voltage vector αβ plane space of a series-wound three-phase four-bridge-arm permanent magnet synchronous motor in an embodiment of this invention is shown;

[0051] Figure 7 A three-dimensional schematic diagram of the voltage vector of a series-wound three-phase four-bridge-arm permanent magnet synchronous motor in an embodiment of this invention is shown;

[0052] Figure 8 A schematic diagram of an alternative voltage modulation vector space in the embodiment of this invention is shown;

[0053] Figure 9 A schematic structural diagram of a model predictive control device for a permanent magnet synchronous motor provided in an embodiment of this invention is shown;

[0054] Figure 10 A schematic diagram of the structure of a computer device provided in an embodiment of this invention is shown.

[0055] Description of the accompanying symbols:

[0056] 100. Alternative voltage modulation vector determination module;

[0057] 200. Working parameter acquisition module;

[0058] 300. Current prediction value calculation module;

[0059] 400. Target current prediction value determination module;

[0060] 500, driver module;

[0061] 1002. Computer equipment;

[0062] 1004, processor;

[0063] 1006. Memory;

[0064] 1008, driving mechanism;

[0065] 1010, input / output module;

[0066] 1012. Input device;

[0067] 1014. Output device;

[0068] 1016. Presentation equipment;

[0069] 1018. Graphical user interface;

[0070] 1020, network interface;

[0071] 1022, communication link;

[0072] 1024. Communication bus. DETAILED DESCRIPTION

[0073] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this document. Obviously, the embodiments described are only part of the embodiments of this document, not all of the embodiments. Based on the embodiments of this document, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this document.

[0074] It should be noted that the terms "first," "second," and the like in the specification and claims herein and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or devices.

[0075] In the existing technology, the control of a series-wound three-phase four-arm permanent magnet synchronous motor mainly adopts a space vector pulse width modulation scheme, which divides the voltage basic vector corresponding to the existing switching state into different sectors. When a certain vector is to be synthesized, the vector is first decomposed into the two voltage vectors closest to it, and then these two voltage vectors are used to represent it. The voltage vectors are used to synthesize the required voltage vectors according to different time proportions, thereby ensuring that the generated voltage waveform is close to a sine wave. However, this method does not eliminate the effect of the zero-sequence component of the voltage vector, and the zero-sequence current harmonics generated by the zero-sequence component bring about large torque fluctuations, thereby affecting the operation of the motor.

[0076] In order to solve the above problems, the embodiment of this paper provides a model predictive control method for a series-wound three-phase four-bridge-arm permanent magnet synchronous motor, which can improve the control efficiency of the series-wound three-phase four-bridge-arm permanent magnet synchronous motor. Figure 1 As shown in the figure, it is the principle diagram of the model predictive control in this method. First, an alternative voltage modulation vector with a zero-sequence component of zero is selected from the voltage vector corresponding to the switching state. Then, the current prediction values ​​corresponding to different alternative voltage modulation vectors are obtained through motor working parameter acquisition, coordinate transformation and model prediction. Then, the target current value is determined by screening the value function through the current prediction value and the given current value. Then, closed-loop control of the motor is realized according to the target control voltage corresponding to the target current value. This article does not require a complex space vector pulse width modulation strategy to achieve stable current control and improve the control ability of the motor.

[0077] The series winding three-phase four-bridge arm permanent magnet synchronous motor can be understood as opening the neutral point of the traditional three-phase motor, connecting the three-phase windings in series, thereby forming four nodes, and then connecting the four nodes to the output end of the four-bridge arm inverter, such as Figure 2 As shown in FIG, the topology of the three-phase four-bridge-arm permanent magnet synchronous motor in this application.

[0078] Specifically, the embodiments of this document provide a model predictive control method for a permanent magnet synchronous motor, which can improve the control efficiency of a three-phase four-bridge-arm permanent magnet synchronous motor with series windings. Figure 3 This is a schematic diagram of the steps of a permanent magnet synchronous motor model predictive control method provided in the embodiment of this article. This specification provides the method operation steps described in the embodiment or flowchart, but based on conventional or non-creative work, more or fewer operation steps may be included. The order of steps listed in the embodiment is only one way of executing the steps among many steps, and does not represent the only execution order. When the actual system or device product is executed, it can be executed in the order or in parallel according to the method shown in the embodiment or the accompanying drawings. Specifically, Figure 3 As shown, the method may include:

[0079] S101: Obtain voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determine multiple candidate voltage modulation vectors based on the voltage vectors, where the zero-sequence component of each candidate voltage vector is zero;

[0080] S102: Collecting the operating parameters of the permanent magnet synchronous motor in the current control period;

[0081] S103: Calculating a current prediction value corresponding to each candidate voltage modulation vector according to the operating parameters and a preset prediction model;

[0082] S104: Obtaining a given current value, and determining a target current prediction value based on the given current value and a plurality of current prediction values;

[0083] S105: Determine the candidate voltage modulation vector corresponding to the target current value as the target control voltage of the next control cycle to achieve drive control of the permanent magnet synchronous motor.

[0084] It can be understood that this paper first determines an alternative voltage modulation vector with a zero zero-sequence component based on the voltage vectors corresponding to the different switching states of the motor, and selects the voltage from the above alternative voltage modulation vectors as the selected voltage for the subsequent control cycle control, thereby suppressing the zero-sequence component on the inverter side and improving the stability of current control. The current prediction value corresponding to each alternative voltage modulation vector is calculated by combining the operating parameters of the permanent magnet synchronous motor in the current control cycle with a preset prediction model (i.e., the motor voltage and motor parameter equations). The current prediction value closer to the given current value is then selected as the target current prediction value for the next control cycle, thereby determining the target control voltage and achieving control of the motor.

[0085] The embodiments of this specification are applicable to three-phase four-arm series winding permanent magnet synchronous motors, such as Figure 2 As shown in the figure, it is the switching state of the inverter topology. This topology includes 8 switching tubes, so 16 different switching states can be obtained, corresponding to permanent magnet synchronous motor voltage vectors of different amplitudes, and the zero-sequence component corresponding to each voltage vector is also different, thus forming a three-phase four-bridge arm series winding permanent magnet synchronous motor voltage vector space, as shown in Figure 6 As shown, it is a schematic diagram of the αβ plane of the voltage vector space, wherein the switch state corresponding to each voltage vector is represented by the number 01, 1 indicates that the corresponding bridge arm is in the upper tube conduction state, and 0 indicates that the corresponding bridge arm is in the lower tube conduction state.

[0086] The operating parameters may be the operating voltage DC bus voltage, the real-time three-phase stator current value, the motor rotor position angle and the target speed. Of course, there may also be other parameter information, which is not limited in the embodiments of this specification.

[0087] The target speed is obtained by the following steps:

[0088] Obtaining the motor rotor position angles at adjacent moments and calculating the motor rotor position angle difference at the adjacent moments;

[0089] Calculate the ratio of the motor rotor position angle difference divided by the time difference between the adjacent moments, and use the ratio as the motor mechanical rotor angular velocity;

[0090] The product of the motor mechanical rotor angular velocity and the number of motor pole pairs is used as the target speed.

[0091] The mechanical rotor angular velocity represents the change in the motor rotor position angle, and the number of pole pairs of the motor is determined by the electrode topology and can be obtained according to actual conditions.

[0092] The DC bus voltage can be acquired through a voltage sensor, and the real-time three-phase stator current value can be acquired through a current sensor, such as a stator three-phase current sensor. The motor rotor position angle can be acquired through a rotor photoelectric encoder. In some other embodiments, there may also be other acquisition devices, which are not described in detail in the embodiments of this specification.

[0093] It should be noted that the above working parameters are sampled data in the three-phase stationary abc coordinate system. In this manual, it is necessary to perform transformations between the two-phase stationary αβ0 coordinate system and the two-phase rotating dq0 coordinate system, and then select a reasonable control method for control through the prediction model provided above. For the three commonly used coordinate systems, the a-axis in the three-phase stationary coordinate system can usually be selected as the reference, the α-axis coincides with the a-axis, and the β-axis leads by 90° phase angle. The angle between the d-axis and the a-axis is defined as the motor rotor position angle θ, and the dq0 coordinate system rotates at the rotor electrical angular velocity. The transformation coefficient between the three-phase stationary coordinate system and the two-phase stationary coordinate system is different depending on the value taken by the equal power transformation and the equal amplitude transformation, such as the equal amplitude Clark transformation and Park transformation, etc. The corresponding setting method is selected according to the actual situation and is not limited in this manual.

[0094] In the embodiments of this specification, Figure 4 As shown, the determining of a plurality of candidate voltage modulation vectors according to the voltage vector includes:

[0095] S201: Determine three phase voltages corresponding to each voltage vector;

[0096] S202: Calculate and obtain a zero-sequence component corresponding to each voltage vector based on the three phase voltages;

[0097] S203: Determine a voltage vector with a zero-sequence component of zero as a candidate voltage modulation vector.

[0098] It can be understood that since each voltage vector corresponds to a zero-sequence component, the three phase voltages corresponding to the voltage vector are the three voltage components of the voltage vector in the ADC coordinate system. The process of obtaining the three phase voltages includes: obtaining the output state of the four-bridge-arm inverter, that is, the conduction status of the upper and lower bridge arms. The motor phase voltage can be obtained by the bridge arm state at both ends of the phase, which is not limited in the embodiments of this specification. The zero-sequence component corresponding to each voltage vector can be obtained by obtaining the three-phase voltage, and the voltage vector with zero zero-sequence component is determined as the alternative voltage modulation vector. In this way, when the motor is driven by the alternative voltage modulation vector, the generation of additional zero-sequence current can be avoided, thereby improving the stability of the motor operation.

[0099] In a further embodiment, calculating the zero-sequence component corresponding to each voltage vector based on the three phase voltages includes:

[0100] An average value of the three phase voltages is calculated according to the three phase voltages, and the average value is used as a zero-sequence component corresponding to the voltage vector.

[0101] Among them, the average value can be the amplitude average value of the three phase voltages, so the zero-sequence component corresponding to the voltage vector is equivalent to the common-mode component of the three-phase voltage of the voltage vector. The zero-sequence component obtained by calculation can expand the two-dimensional three-phase four-bridge arm winding group permanent magnet synchronous motor voltage vector space to three dimensions, and show the direction and amplitude of the zero-sequence component in the three-dimensional space, such as Figure 7 As shown in FIG, a three-dimensional voltage vector space diagram of a three-phase four-bridge-arm winding group permanent magnet synchronous motor.

[0102] In actual work, taking the (1000) switch state as an example, the amplitudes of the three-phase voltages are: u a =u dc –0=u dc ,u b =0–0=0,u c =0–0=0, then the zero sequence component is u0=(u a +u b +u c ) / 3=u dc / 3, the 16 switching states of the three-phase four-bridge arm series-wound permanent magnet synchronous motor correspond to 16 voltage vectors. The zero-sequence component of each voltage vector can be obtained by calculating the zero-sequence component, as shown in Table 1 below, which is a comparison table of the zero-sequence components of the voltage vector corresponding to different switching states:

[0103] Table 1

[0104]

[0105] The numbers corresponding to the voltage vectors in Table 1 (e.g., 0001) represent different switching states. From Table 1, it can be determined that there are a total of 8 voltage vectors with zero zero-sequence components, that is, eight alternative voltage modulation vectors are determined. Therefore, different alternative voltage modulation vectors can be obtained by simply adjusting the switching state and the application time of the switching state in each control cycle, thereby realizing the driving of the permanent magnet synchronous motor, such as Figure 8 Part a is a schematic diagram of the voltage vectors corresponding to the 16 switching states in the αβ plane. Figure 8 Part b is a spatial distribution diagram of the eight selected candidate voltage modulation vectors, which is a new hexagonal area. When voltage vector modulation is performed in the hexagonal area, the output common mode component can be zero.

[0106] The above steps can be used to obtain the candidate voltage modulation vector, and then the control voltage vector of the next control cycle can be selected according to the working parameters of the motor in the current control cycle. As an option, Figure 5 As shown, according to the operating parameters and the preset prediction model, the current prediction value corresponding to each candidate voltage modulation vector is calculated, including:

[0107] S301: Acquire the operating parameters, where the operating parameters include a three-phase stator current of the permanent magnet synchronous motor and a motor rotor position angle;

[0108] S302: converting the three-phase stator current into a direct-axis component and a quadrature-axis component of the stator current through coordinates, and obtaining a rotor electrical angular velocity from the motor rotor position angle through a differentiation process;

[0109] S303: Converting the candidate voltage modulation vector into a direct-axis component and a quadrature-axis component of a voltage vector through coordinates;

[0110] S304: Obtain a current prediction value corresponding to each candidate voltage modulation vector by calculating using a preset prediction model according to the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity.

[0111] It can be understood that after obtaining the motor rotor position angle θ, the rotor electrical angular velocity ω can be obtained through the differential process. e ; Then the three-phase stator winding current i is obtained by collecting A 、i B 、i C , combined with the rotor position information, after abc-dq coordinate transformation, the (direct axis) d and (quadrature axis) q axis feedback current values ​​i are obtained d 、i q , the above-mentioned alternative voltage modulation vector is transformed into the direct axis component u of the voltage vector by coordinate transformation dref and quadrature axis component u qref Finally, the above data is combined with the voltage prediction model to obtain the motor current prediction value.

[0112] The specific conversion process is not limited in this embodiment of the specification.

[0113] Alternatively, the voltage prediction model may be expressed by the following formula (1):

[0114]

[0115] Among them, u dref and u qref are the direct-axis and quadrature-axis components of the alternative voltage modulation vector, L d and L q is the inductance of the motor on the direct and quadrature axes, i dref is the direct-axis predicted value of the motor stator current, i qref is the predicted value of the motor stator current quadrature axis, Rs is the resistance of the motor, Ts is the control cycle time of the controller, ω e is the electrical angular velocity of the motor, Ψ f is the flux linkage of the motor’s permanent magnet, i d (k) is the direct axis component of the motor real-time current coordinate conversion in the current control cycle, i d (k) is the quadrature axis component after the real-time current coordinate transformation of the motor in the current control cycle.

[0116] In a further embodiment, in order to improve the utilization rate of the motor performance, the current prediction value corresponding to each candidate voltage modulation vector is calculated by a preset prediction model based on the direct-axis component and the quadrature-axis component of the stator current, the direct-axis component and the quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, including:

[0117] The direct axis component of the current prediction value (i.e., the stator current direct axis prediction value i dref ) is set to the specified value;

[0118] According to the specified value, combined with the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, the quadrature-axis prediction value of the current prediction value corresponding to each alternative voltage modulation vector is calculated through a preset prediction model.

[0119] Alternatively, i dref =0, the quadrature-axis component of the current prediction value is calculated by the above formula (1) (the quadrature-axis component of the current prediction value can be called the current prediction value at this time), which can avoid the generation of direct-axis current and improve the stability and reliability of the motor operation.

[0120] This specification can determine the current prediction value corresponding to each alternative voltage modulation vector through the above formula (1) and the working parameters of the current control cycle of the motor. In actual work, in order to ensure the stability of the motor operation and maximize the performance, a quick-break control loop (such as a PI controller) is usually set to obtain a given current value for the next control cycle. The given current value can be understood as the theoretical current value input to the motor in the next cycle. However, since the input current of the motor is achieved by adjusting the switching state, in order to avoid generating zero-sequence current and ensure the stability of the motor operation at the same time, the embodiment of this specification selects the best one among the alternative voltage modulation vectors as the control voltage for the next control cycle.

[0121] In a further embodiment, the given current value is obtained by the following steps:

[0122] Determine the target speed of the current control cycle;

[0123] A given current value is obtained through PI control according to the target rotational speed and the rotor electrical angular velocity.

[0124] The given current value is the theoretical current value input to the motor in the next cycle, which can be obtained by subtracting the target speed from the rotor electrical angular velocity (i.e., the feedback speed) and inputting it into a proportional-integral controller to obtain the given current value (i.e., the q-axis current value). Therefore, based on obtaining the given current value and the current prediction value corresponding to each alternative voltage modulation vector, a closer current prediction value can be determined. Optionally, obtaining the given current value and determining the target current prediction value based on the given current value and multiple current prediction values ​​includes:

[0125] Calculating an evaluation value of each current prediction value by using a cost function according to the given current value and the plurality of current prediction values;

[0126] The current prediction value with the smallest evaluation value is taken as the target current prediction value.

[0127] In the embodiment of this specification, the value function can be expressed by the following formula (2):

[0128]

[0129] Among them, g is the evaluation value, i qref is the predicted value of stator current (i.e. the quadrature-axis component of the predicted current), is a given current value.

[0130] Through the above steps, the current prediction value with the smallest deviation from the given current value can be obtained, thereby determining the target current prediction value. Based on the determination of the target current prediction value, its corresponding alternative voltage modulation vector can be determined. The alternative voltage modulation vector is the target control voltage. Finally, the motor operation in the next control cycle is controlled by the switch state corresponding to the target control voltage.

[0131] The embodiments of this specification provide a prediction model notification method for a three-phase, four-leg series-wound permanent magnet synchronous motor. Compared to traditional open-winding three-phase motor control strategies, this control algorithm, based on a three-phase, four-leg inverter topology, reduces hardware costs while fully leveraging the performance advantages of three-phase motors and improving their control performance. Compared to conventional three-phase motors, this series-wound three-phase motor control algorithm can improve the motor's output torque and maximum speed, provide faster torque response, and effectively suppress zero-sequence components introduced by the inverter.

[0132] Based on the same inventive concept, the embodiment of this specification also provides a permanent magnet synchronous motor model predictive control device, such as Figure 9 As shown, the device includes:

[0133] The candidate voltage modulation vector determination module 100 is configured to obtain voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determine a plurality of candidate voltage modulation vectors based on the voltage vectors, wherein the zero-sequence component of each candidate voltage vector is zero;

[0134] The operating parameter acquisition module 200 is used to acquire the operating parameters of the permanent magnet synchronous motor in the current control cycle;

[0135] A current prediction value calculation module 300 is configured to calculate a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model;

[0136] a target current prediction value determination module 400, configured to obtain a given current value and determine a target current prediction value based on the given current value and a plurality of current prediction values;

[0137] The driving module 500 is configured to determine the candidate voltage modulation vector corresponding to the target current value as the target control voltage of the next control cycle, so as to realize drive control of the permanent magnet synchronous motor.

[0138] The beneficial effects achieved by the above-mentioned device are consistent with the intended effects achieved by the above-mentioned method, and will not be described in detail in the embodiments of this specification.

[0139] In some other embodiments, a driver is provided herein, comprising: the driver is used to control a series-winding three-phase four-bridge-arm permanent magnet synchronous motor, the driver comprising a memory and a controller;

[0140] The memory stores a computer program executable on the controller;

[0141] When the controller executes the computer program, the control method described above is implemented.

[0142] In some other embodiments, this document also provides a motor system, which includes a series-wound three-phase four-bridge-arm permanent magnet synchronous motor and the drive described above.

[0143] In some other embodiments, this document further provides an electrical device comprising the aforementioned motor system. The electrical device may be a small servo device, such as a small robotic arm. In some other embodiments, the electrical device may also be an assembly line system configured with a servo link including the aforementioned motor. This invention achieves extreme performance improvements without modifying the motor structure, and also addresses the issue of large torque fluctuations during operation of open-winding motors.

[0144] like Figure 10As shown, a computer device provided in an embodiment of the present invention is shown. The computer device 1002 may include one or more processors 1004, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. The computer device 1002 may also include any memory 1006 for storing any type of information, such as code, settings, data, etc. For example, without limitation, the memory 1006 may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, etc. More generally, any memory may use any technology to store information. Furthermore, any memory may provide volatile or non-volatile retention of information. Furthermore, any memory may represent a fixed or removable component of the computer device 1002. In one embodiment, when the processor 1004 executes associated instructions stored in any memory or combination of memories, the computer device 1002 may perform any operation of the associated instructions. The computer device 1002 also includes one or more drive mechanisms 1008, such as a hard disk drive mechanism, an optical disk drive mechanism, etc., for interacting with any memory.

[0145] Computer device 1002 may also include an input / output module 1010 (I / O) for receiving various inputs (via input device 1012) and providing various outputs (via output device 1014). A specific output mechanism may include a presentation device 1016 and an associated graphical user interface (GUI) 1018. In other embodiments, input / output module 1010 (I / O), input device 1012, and output device 1014 may not be included, and the computer device 1002 may simply be a computer device in a network. Computer device 1002 may also include one or more network interfaces 1020 for exchanging data with other devices via one or more communication links 1022. One or more communication buses 1024 couple the components described above together.

[0146] The communication link 1022 may be implemented in any manner, for example, via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 1022 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0147] Corresponding to Figure 3-Figure 5 The embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which executes the steps of the above method when executed by a processor.

[0148] The embodiment of the present invention also provides a computer readable instruction, wherein when the processor executes the instruction, the program causes the processor to execute the following Figures 3 to 5 The method shown.

[0149] It should be understood that in the various embodiments of this document, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0150] It should also be understood that in the embodiments herein, the term "and / or" merely describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" could represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0151] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0152] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0153] In the several embodiments provided herein, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices, or units, or can be an electrical, mechanical, or other form of connection.

[0154] 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 units may be selected according to actual needs to achieve the purpose of the embodiments herein.

[0155] In addition, the functional units in the various embodiments herein may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0156] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this article is essentially or the part that contributes to the existing technology, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this article. The aforementioned storage medium includes: various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0157] This article uses specific embodiments to illustrate the principles and implementation methods of this article. The description of the above embodiments is only used to help understand the methods and core ideas of this article. At the same time, for those skilled in the art, based on the ideas of this article, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation to this article.

Claims

1. A permanent magnet synchronous motor model predictive control method, characterized in that: The method is applied to a series-wound three-phase four-bridge-arm permanent magnet synchronous motor, comprising: Obtaining voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determining a plurality of candidate voltage modulation vectors based on the voltage vectors, wherein the zero-sequence component of each candidate voltage vector is zero; Collect the operating parameters of the permanent magnet synchronous motor in the current control cycle; Calculating a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model; Obtaining a given current value, and determining a target current prediction value based on the given current value and a plurality of current prediction values; Determining the candidate voltage modulation vector corresponding to the target current prediction value as the target control voltage of the next control cycle to achieve drive control of the permanent magnet synchronous motor; The method of determining a plurality of candidate voltage modulation vectors according to the voltage vector comprises: Determine the three phase voltages corresponding to each voltage vector; Calculating an average value of the three phase voltages according to the three phase voltages, and using the average value as a zero-sequence component corresponding to the voltage vector; A voltage vector having a zero-sequence component of zero is determined as a candidate voltage modulation vector.

2. The method according to claim 1, characterized in that Calculating a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model includes: Acquiring the operating parameters, wherein the operating parameters include a three-phase stator current of the permanent magnet synchronous motor and a motor rotor position angle; Converting the three-phase stator current into a direct-axis component and a quadrature-axis component of the stator current through coordinates, and obtaining the rotor electrical angular velocity through a differential process of the motor rotor position angle; Converting the candidate voltage modulation vector into a direct-axis component and a quadrature-axis component of a voltage vector through coordinates; According to the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, a current prediction value corresponding to each alternative voltage modulation vector is calculated through a preset prediction model.

3. The method according to claim 2, characterized in that The method of calculating the current prediction value corresponding to each candidate voltage modulation vector by a preset prediction model based on the direct-axis component and the quadrature-axis component of the stator current, the direct-axis component and the quadrature-axis component of the voltage vector, and the rotor electrical angular velocity includes: Setting the direct-axis component of the current prediction value to a specified value; According to the specified value, combined with the direct-axis component and quadrature-axis component of the stator current, the direct-axis component and quadrature-axis component of the voltage vector, and the rotor electrical angular velocity, the quadrature-axis prediction value of the current prediction value corresponding to each alternative voltage modulation vector is calculated through a preset prediction model.

4. The method according to claim 2, characterized in that The obtaining of a given current value comprises: Determine the target speed of the current control cycle; A given current value is obtained through PI control according to the target rotational speed and the rotor electrical angular velocity.

5. The method according to claim 1, wherein The obtaining of a given current value and determining a target current prediction value based on the given current value and a plurality of current prediction values ​​includes: Calculating an evaluation value of each current prediction value by using a cost function according to the given current value and the plurality of current prediction values; The current prediction value with the smallest evaluation value is taken as the target current prediction value.

6. A permanent magnet synchronous motor model predictive control device, characterized in that: The device is applied to a series-wound three-phase four-bridge-arm permanent magnet synchronous motor, comprising: an alternative voltage modulation vector determination module, configured to obtain voltage vectors corresponding to all switching states of the permanent magnet synchronous motor, and determine a plurality of alternative voltage modulation vectors based on the voltage vectors, wherein the zero-sequence component of each of the alternative voltage vectors is zero; Working parameter acquisition module, used to collect the working parameters of the permanent magnet synchronous motor in the current control cycle; a current prediction value calculation module, configured to calculate a current prediction value corresponding to each candidate voltage modulation vector based on the operating parameters and a preset prediction model; a target current predicted value determination module, configured to obtain a given current value and determine a target current predicted value based on the given current value and a plurality of current predicted values; a driving module, configured to determine the candidate voltage modulation vector corresponding to the target current prediction value as the target control voltage of the next control cycle, so as to realize drive control of the permanent magnet synchronous motor; The method of determining a plurality of candidate voltage modulation vectors according to the voltage vector comprises: Determine the three phase voltages corresponding to each voltage vector; Calculating an average value of the three phase voltages according to the three phase voltages, and using the average value as a zero-sequence component corresponding to the voltage vector; A voltage vector having a zero-sequence component of zero is determined as a candidate voltage modulation vector.

7. A driver, characterized in that: The driver includes: a memory and a controller; The memory stores a computer program executable on the controller; When the controller executes the computer program, the control method according to any one of claims 1 to 5 is implemented.

8. A motor system, characterized in that: The system includes a series-wound three-phase four-bridge-arm permanent magnet synchronous motor and the driver according to claim 7.

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