A dead-time compensation method for deadbeat predictive current control of permanent magnet synchronous motor

Abstract

The application relates to the technical field of current harmonic suppression and discloses a dead-time compensation method for deadbeat prediction current control of a permanent magnet synchronous motor. The method comprises the following steps: establishing a motor model of the permanent magnet synchronous motor; obtaining ideal control voltage of the permanent magnet synchronous motor in a current sampling period through a deadbeat current prediction control method according to the motor model; predicting the rotor flux increment and the change amount of the stator side induced electromotive force of the permanent magnet synchronous motor in the current sampling period through the motor model according to the operation state and the motor parameters of the permanent magnet synchronous motor, so as to obtain a disturbance voltage generated by the dead-time of the permanent magnet synchronous motor; superimposing the disturbance voltage and the ideal control voltage to obtain target control voltage, and driving a three-phase inverter of the permanent magnet synchronous motor through the target control voltage, so as to control the operation of the permanent magnet synchronous motor. The application can solve the problems of the increase of current harmonic content and the increase of motor torque ripple caused by the dead-time of the permanent magnet synchronous motor.

Description

Technical Field

[0001] This invention relates to the field of current harmonic suppression technology, and in particular to a dead zone compensation method, device, equipment and medium for dead-zone compensation in predictive current control of permanent magnet synchronous motors without deadbeat. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) have become the preferred choice for drive motors due to their high power density, high efficiency, and high reliability. Currently, the main current control methods for PMSMs include hysteresis current control (HCC), proportional-integral (PI) control, sliding mode control (SMC), and predictive control (PC). In recent years, with the rapid development of embedded chip technology, predictive control, with its clear concept, simple structure, and fast dynamic performance, has been increasingly widely used in motor drive systems with microsecond-level control cycles. Therefore, research on predictive current control (PCC) is of great significance for improving the control system performance of new energy vehicle drive systems and enhancing their dynamic performance and ride comfort.

[0003] Deadbeat Predictive Current Control (DPCC), a type of predictive current control, modulates the voltage vector obtained from the predictive model using Space Vector Pulse Width Modulation (SVPWM) and then applies it to the inverter. Its fixed switching frequency reduces current ripple and computational complexity, and it has been widely used in high-performance motor applications. To prevent shoot-through in one arm of the inverter, which could lead to a short-circuit fault, a dead time is required. However, due to the voltage drop across the switching transistors and the dead time, the actual output voltage of the inverter cannot be equal to the given voltage vector. Especially at low motor speeds, the small duty cycle of PWM, coupled with the significant impact of the dead time and transistor voltage drop, increases the harmonic content of the controller, severely distorts the current waveform, and leads to larger fluctuations in the motor's output torque, thus deteriorating both the dynamic and steady-state performance of the system. Summary of the Invention

[0004] The purpose of this invention is to provide a dead-zone compensation method, device, equipment, and medium for dead-zone predictive current control of permanent magnet synchronous motors without deadbeat. This can solve the problem that when the motor speed is low, the small duty cycle of pulse width modulation (PWM) results in a large impact of dead zone and tube voltage drop, which increases the harmonic content of the controller, causes severe distortion of the current waveform, and leads to larger fluctuations in the output torque of the motor, resulting in poor dynamic and steady-state performance of the system.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor, comprising the following steps: Establish a motor model for the permanent magnet synchronous motor; Based on the motor model, the ideal control voltage of the permanent magnet synchronous motor within one current sampling period is predicted by the deadbeat current prediction control method. Based on the operating status and parameters of the permanent magnet synchronous motor, the rotor flux increment and the change in stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle are predicted by the motor model in order to obtain the disturbance voltage generated by the permanent magnet synchronous motor due to the dead time. The target control voltage is obtained by superimposing the disturbance voltage and the ideal control voltage, and the three-phase inverter of the permanent magnet synchronous motor is driven by the target control voltage to control the operation of the permanent magnet synchronous motor.

[0006] Furthermore, the establishment of the motor model for the permanent magnet synchronous motor includes: A first motor model of a permanent magnet synchronous motor in a three-phase stationary abc coordinate system is established. The first motor model is transformed by Clarke and Park to obtain the second motor model in a two-phase rotating dq coordinate system.

[0007] Furthermore, the second motor model consists of the voltage equation, torque equation, and flux linkage equation of a permanent magnet synchronous motor, which are as follows: ; ; The flux linkage equation is: ; In the formula, R For stator resistance, u d , u q , i d , i q They are dq Shaft voltage and stator current, L d and Lq yes dq The stator inductance value of the shaft, ω e It is electric angular velocity. It is a permanent magnet flux chain. T e It is electromagnetic torque. n p It is an extreme logarithm. and This represents the components of the stator flux linkage along the d-axis and q-axis. L d and L q This represents the d-axis inductance and the q-axis inductance. It is a permanent magnet flux linkage.

[0008] Furthermore, the disturbance voltage generated by the dead time of the permanent magnet synchronous motor is obtained through the following steps: Establish a stationary coordinate system Voltage equation for a permanent magnet synchronous motor: ; In the formula, u , u , i , i These are the stationary coordinate systems. Under voltage and stator current, L s It is the stator inductance value. The back electromotive force component; Obtain the actual voltage when the dead-time effect exists: ; In the formula, This is the dead zone equivalent disturbance voltage; The Park transformation yields the result in the rotating coordinate system. dq Compensation voltage under f d , f q : ; Combine a sampling period T i Current deviation values ​​of the perpendicular and direct axes in the internal rotating coordinate system: ; In the formula, i d , i q One sampling period T i Current deviation value along the direct axis in the internal rotating coordinate systeme d , e q The back electromotive force component along the dq axis; The formula for estimating the disturbance voltage is derived as follows: .

[0009] Further, the step of obtaining the ideal control voltage of the permanent magnet synchronous motor within one current sampling period using the deadbeat current prediction control method based on the motor model includes: The voltage equation is subjected to first-order forward difference to obtain the predicted current expression of the permanent magnet synchronous motor at a certain moment, and the control voltage expression of the permanent magnet synchronous motor at a certain moment is determined based on the predicted current expression. The ideal control voltage of the permanent magnet synchronous motor within one current sampling period is obtained based on the control voltage expression.

[0010] Furthermore, prior to the three-phase inverter that drives the permanent magnet synchronous motor via the target control voltage, the following is also included: The target control voltage is low-pass filtered.

[0011] Embodiments of the present invention also provide a dead-zone compensation device for dead-time predictive current control of a permanent magnet synchronous motor, comprising: The model building module is used to build the motor model of the permanent magnet synchronous motor; The ideal voltage prediction module is used to obtain the ideal control voltage of the permanent magnet synchronous motor within one current sampling period based on the motor model and using the deadbeat current prediction control method. The disturbance voltage acquisition module is used to predict the changes in rotor flux linkage and stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle based on the operating status and motor parameters of the permanent magnet synchronous motor, so as to obtain the disturbance voltage generated by the permanent magnet synchronous motor due to the dead time. The disturbance voltage compensation module is used to superimpose the disturbance voltage with the ideal control voltage to obtain the target control voltage, and then drive the three-phase inverter of the permanent magnet synchronous motor through the target control voltage to control the operation of the permanent magnet synchronous motor.

[0012] Embodiments of the present invention also provide a computer device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the dead-zone compensation method for dead-zone predictive current control of a permanent magnet synchronous motor as described above.

[0013] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the dead-zone compensation method for dead-zone predictive current control of a permanent magnet synchronous motor.

[0014] The dead-zone compensation method for dead-time predictive current control of permanent magnet synchronous motors provided by this invention has at least the following beneficial effects: By analyzing the operating status and parameters of the permanent magnet synchronous motor (PMSM), the rotor flux increment and the change in stator-side induced electromotive force are estimated to obtain the disturbance voltage caused by the dead time. Feedforward compensation is then performed, and the disturbance voltage is superimposed with the ideal control voltage to obtain the target control voltage. This target control voltage drives the three-phase inverter of the PMSM to control its operation. This method significantly improves the output voltage waveform of the PMSM inverter by compensating for the voltage error caused by the dead time effect, reduces the harmonic content of the motor stator current, and decreases the pulsation of the motor output torque. It is suitable for PMSM drive applications with high low-speed performance requirements. Furthermore, traditional dead time compensation strategies typically require high accuracy in current polarity detection, while this invention does not require any additional hardware circuitry for current polarity detection, effectively solving the problem of difficult current polarity detection in traditional dead time compensation processes. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0016] Figure 1 A flowchart illustrating a dead-zone compensation method for dead-zone predictive current control of a permanent magnet synchronous motor provided by the present invention. Figure 2 This invention provides a schematic diagram of dead-zone compensation control for dead-zone predictive current control of a permanent magnet synchronous motor without deadbeat. Figure 3 A schematic diagram of experimental results comparison provided by the present invention Figure 1 ; Figure 4 A schematic diagram of experimental results comparison provided by the present invention Figure 2 . Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] As can be seen from the background technology, there is currently a need for a compensation method to improve a series of problems caused by dead time, which affect the steady-state static error and dynamic fast response capability of the DPCC algorithm.

[0019] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] One embodiment of the present invention relates to a dead-zone compensation method for dead-zone predictive current control of a permanent magnet synchronous motor without deadbeat. The specific flow of the dead-zone compensation method for dead-zone predictive current control of a permanent magnet synchronous motor in this embodiment can be as follows: Figure 1 As shown, it includes: Step 101: Establish the motor model of the permanent magnet synchronous motor.

[0021] Step 102: Based on the motor model, obtain the ideal control voltage of the permanent magnet synchronous motor within one current sampling period using the deadbeat current prediction control method.

[0022] Step 103: Based on the operating status and parameters of the permanent magnet synchronous motor, predict the changes in rotor flux linkage and stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle using the motor model, so as to obtain the disturbance voltage generated by the dead time of the permanent magnet synchronous motor.

[0023] Step 104: The disturbance voltage is superimposed with the ideal control voltage to obtain the target control voltage, and the three-phase inverter of the permanent magnet synchronous motor is driven by the target control voltage to control the operation of the permanent magnet synchronous motor.

[0024] The following is a detailed description of the implementation details of the dead zone compensation method for the dead-zone predictive current control of permanent magnet synchronous motors in this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0025] In step 101, a first motor model of a permanent magnet synchronous motor in a three-phase stationary abc coordinate system is first established, and then the first motor model is transformed by Clarke transformation and Park transformation to obtain a second motor model in a two-phase rotating dq coordinate system.

[0026] In practical implementation, the derivation of the dynamic model of a permanent magnet synchronous motor usually requires the following assumptions to simplify the analysis: 1) The magnetomotive force generated by the three-phase symmetrical winding of the stator is distributed according to a sinusoidal law, and the higher harmonics of the stator magnetic field are ignored. The back electromotive force of the motor is also distributed according to a sinusoidal law. 2) Assume that the permanent magnet has no damping effect and the stator has an undamped winding; 3) Ignore the cogging effect, assume that the stator and rotor surfaces are smooth, and assume that the air gap magnetic field thickness is uniform; 4) Ignore magnetic circuit saturation, eddy current effects, and hysteresis losses, and assume that the motor's magnetic circuit is linear; 5) The self-inductance and mutual inductance between each winding are constant.

[0027] Based on the above assumptions, the three-phase stationary... a - b - c The voltage equation of a permanent magnet synchronous motor in the coordinate system is: ; In the formula, p For differential operators, R For stator resistance, and These are the three-phase stator voltage and current, respectively. This refers to the flux linkage of the three-phase stator winding.

[0028] The flux linkage equation is: ; In the formula, It is a permanent magnet flux chain. L aa express a stator winding self-inductance M ab express ab mutual inductance between phase stator windings Indicates permanent magnet flux linkage and a The same applies to the cross-linking magnetic flux of the phases, and others.

[0029] The electromagnetic torque equation is: ; In the formula, T e Represents electromagnetic torque. n p Represents the extreme logarithm.

[0030] The dynamic model of a permanent magnet synchronous motor can be represented by windings located on the quadrature axis and the direct axis (i.e., d, q The two-phase motor with a shaft () is derived. The two-phase rotating... (after Clarke transform and Park transform) d - q The PMSM voltage equation in the coordinate system is:

[0031] ; In the formula, u d , u q , i d , i q They are dq Shaft voltage and stator current, L d and L q yes dq The stator inductance value of the shaft, ω e It is electric angular velocity.

[0032] The torque equation is: .

[0033] The flux linkage equation is: ; In the formula, and This represents the components of the stator flux linkage along the d-axis and q-axis; L d and L q This represents the d-axis inductance and the q-axis inductance. It is a permanent magnet flux linkage.

[0034] In step 102, the voltage equation in the two-phase rotating dq coordinate system is subjected to first-order forward difference to obtain the predicted current expression of the permanent magnet synchronous motor at a certain moment. Based on the predicted current expression, the control voltage expression of the permanent magnet synchronous motor at a certain moment is determined, thereby obtaining the ideal control voltage of the permanent magnet synchronous motor within a current sampling period based on the control voltage expression.

[0035] In practical implementation, the principle of deadbeat current predictive control is derived based on the motor's physical model: Deadbeat current predictive control, also known as minimum beat current control, requires the actual current to follow the target current value within the minimum control cycle. The current control voltage of deadbeat current predictive control is calculated based on the motor's discrete mathematical model and reference current, and is applied to the inverter to generate a switching signal through coordinate transformation and SVPWM modulation so that the actual current can accurately follow the reference current at the next moment. This embodiment uses a three-phase surface-mounted permanent magnet synchronous motor (SPMSM) for scheme illustration. dq The stator inductance value of the shaft should meet the following conditions:

[0036] ; Substituting the above equation into the two-phase rotation... d - q The PMSM voltage equation in the coordinate system, when derived by its first-order forward difference, yields the... k The expression for the predicted current at time +1 is: ; in G ( k ), H, E ( k It can be represented in the following form: ; And in the above formula u d ( k ), u q ( k ), i d ( k ), i q ( k ) are respectively dq Axis at the k Voltage and stator current at time t, i d ( k + 1) and i q ( k+ 1) For dq Axis at the k Stator current at time +1 ω e ( k ) is the first k electric angular velocity at time t, T s This refers to the sampling time of the control system.

[0037] From the above formula, we can obtain the first... k Moment dq The expression for the shaft control voltage is: ; The control voltage needs to ensure that the actual current at the next moment accurately follows the reference current, therefore the first... k Reference current at time +1 i * d ( k +1) and i * q ( k +1) Replace the firstk The actual current at time +1 i d ( k+ 1) and i q ( k+ 1), therefore dq The equation for the shaft control voltage can be rewritten as: ; The first one is calculated using the above formula. k The predicted control voltage at the given moment is then applied to the inverter via SVPWM. Theoretically, after one sampling cycle, the actual current can accurately follow the given current. However, in practical digital control systems, due to delays in current sampling and algorithm calculation, the predicted control voltage at the given moment is not always accurate. k Control voltage for each sampling period u ( k ) can only be in the ( k Loading for +1) sampling periods requires control delay compensation, specifically:

[0038] ; Assuming the sampling time is short enough, the reference current i * d and i * q and electric angular velocity ω e It can be assumed that it remains unchanged between two adjacent sampling periods, that is: ; The predictive control voltage for deadbeat current predictive control with one-beat delay compensation can be obtained as follows: .

[0039] In step 103, the traditional dead-time effect compensation strategy used in most cases requires high accuracy in current polarity detection, which is very difficult. These problems greatly increase the difficulty of implementing the dead-time compensation algorithm. This embodiment proposes a feedforward compensation method to improve the dead-time effect based on the idea of ​​feedforward control. This method does not require current polarity detection and can effectively solve the problem of difficult current polarity detection during dead-time compensation. Specifically, this embodiment constructs a disturbance voltage observer based on the vector operation of the flux linkage increment and the estimated back electromotive force, and uses a feedforward method to improve the impact of dead-time.

[0040] The dead-zone feedforward compensation method estimates the voltage distortion caused by the dead zone and adds it to the drive signal of the three-phase inverter. The dead-zone feedforward compensator is composed of the voltage setpoint output by the current loop, the rotor position, the quadrature and direct axis currents in the two-phase rotating coordinate system, the motor phase resistance, and the motor phase inductance, which reduces the impact of the dead-zone effect.

[0041] In the dead zone compensation process, consider the stationary coordinate system. Voltage equation for a permanent magnet synchronous motor: ; In the formula, u , u , i , i These are the stationary coordinate systems. Under voltage and stator current, L s It is the stator inductance value. This is the back electromotive force component.

[0042] If the dead-time effect is introduced, the actual voltage should be expressed as: ; In the formula, This is the dead zone equivalent disturbance voltage.

[0043] The Park transformation yields the result in the rotating coordinate system. dq Compensation voltage under f d , f q : ; Since the polarity of the disturbance voltage and current caused by the inverter dead time is not directly related, the detection current polarity can be disregarded when compensating for the disturbance voltage, thus avoiding the influence of current clamping on the dead time disturbance voltage compensation. In this embodiment, the selected current sampling frequency is much lower than the system's PWM frequency, allowing for the acquisition of the current derivative in a synchronous rotating coordinate system. i d / T i , i q / T i At this point, the sign of the change in current does not represent the direction of the current in a specific phase.

[0044] This embodiment uses the "magnetic flux increment-back electromotive force estimation" method to derive the disturbance voltage. Since the electromagnetic response of the motor is much faster than its mechanical response, the rotor position can be considered essentially unchanged within one sampling period. Therefore, the current increment is mainly determined by the applied voltage and the disturbance voltage. Hence:

[0045] ; In the formula, i d , i q One sampling period T i Current deviation value along the direct axis in the internal rotating coordinate system e d , e q Let be the back electromotive force component along the dq axis. T i One sampling period.

[0046] The formula for estimating the disturbance voltage is derived as follows: ; In the compensation stage, the estimated disturbance voltage is directly added to the voltage setpoint to obtain the corrected voltage command: ; In the formula, and It is the given target voltage value along the perpendicular and perpendicular axes.

[0047] The above equation shows the relationship between the disturbance voltage caused by the dead-zone effect and the change in current within one current sampling period, and the dead-zone disturbance voltage is independent of the rotor position information. Combining the dead-zone disturbance voltage with the dynamic voltage equation of the permanent magnet synchronous motor yields the relationship between the change in current and the disturbance compensation voltage. Since the mechanical response of the motor lags behind its electromagnetic response, the change in rotor electrical angle can be ignored within one current sampling period. The inverter output voltage deviation caused by the dead-zone effect is related to the motor's AC and DC axis currents, rotor angular velocity, phase inductance, and rotor flux linkage, and is independent of the rotor's position. This dead-zone compensation method avoids many of the shortcomings and errors of traditional dead-zone compensation, thus ensuring the stability and accuracy of the dead-zone disturbance voltage observer.

[0048] In step 104, before driving the three-phase inverter of the permanent magnet synchronous motor with the target control voltage, the target control voltage is first low-pass filtered. Specifically, considering the influence of the rotor mechanical response on the calculation of the stator-side induced electromotive force change, the current sampling frequency must be increased. However, this will increase the noise of the sampled current. To improve the accuracy of the disturbance voltage compensation value, a first-order low-pass filter with a cutoff frequency of several hundred hertz must be introduced to filter out part of the current sampling noise. The time delay caused by this filter is less than the PWM period of the system, and its impact on the calculation and compensation effect of the dead-zone disturbance voltage is negligible. The low-pass filter cutoff frequency selected in this invention is 600Hz.

[0049] This embodiment improves the performance of the vector controller for the permanent magnet synchronous motor by using a dead-time disturbance observer to compensate for the effect of dead time. The disturbance voltage is calculated by observing the flux linkage increment parameter and the unit back electromotive force function. The calculated disturbance voltage is then fed forward to the output of the current controller to compensate for the dead-time effect. This method does not require any additional hardware circuitry for current polarity detection.

[0050] Based on this, the present invention provides a vector control method for permanent magnet synchronous motors with dead-time compensation. This method aims to solve the problems of output voltage distortion, increased current harmonic content, and increased motor torque ripple caused by inverter dead time, especially the deterioration of system performance under low-speed conditions. The core of this method lies in proposing and implementing a novel dead-time feedforward compensation scheme, which constructs a disturbance voltage observer based on flux linkage increment vector calculation and back EMF estimation. Specific implementation steps include: First, using the current loop output voltage setpoint, rotor position, quadrature and direct axis currents, motor phase resistance and inductance, combined with flux linkage increment parameters and unit back EMF function, the disturbance voltage component caused by the dead-time effect is estimated online. Then, feedforward compensation is performed: the estimated disturbance voltage is fed forward and superimposed onto the output of the current regulator, i.e., the input voltage setpoint signal of the SVPWM modulation stage. Next, noise suppression is performed by introducing a low-pass filter with a cutoff frequency of approximately 600Hz at the compensation voltage output to filter out the influence of current sampling noise, while ensuring that its impact on the compensation effect is negligible.

[0051] This method allows for the control of permanent magnet synchronous motors through a system: The system comprises a speed outer loop, a current inner loop, a delay compensation module, a dead-zone compensation module, an SVPWM modulation module, and an inverter drive and feedback module. The speed outer loop uses a PI controller to calculate the desired current components on the d and q axes based on the difference between the set target speed and the current feedback speed of the motor. The current inner loop is based on a deadbeat predictive control strategy, combining the mathematical model of the permanent magnet synchronous motor with the current, voltage, and speed state parameters at the current moment to predict the voltage control quantity required for the next sampling cycle. To overcome the inherent one-beat delay problem of digital control systems, a delay compensation mechanism is adopted to align the predicted voltage control quantity with the current control output. Simultaneously, to address the dead-zone effect caused by the non-ideal characteristics of power devices in the inverter, a dead-zone feedforward compensation module is designed to further correct the predicted voltage based on information such as current direction, electrical angle, and switching status, obtaining the compensation voltage used for modulation. Subsequently, the SVPWM modulation module receives the corrected voltage reference quantity and the current electrical angle information, generates a three-phase space vector modulation signal, drives the three-phase inverter to output a PWM waveform, and controls the operation of the permanent magnet synchronous motor. A control diagram can be found in [reference needed]. Figure 2The system samples the three-phase current output from the inverter and obtains the dq-axis current components through coordinate transformation, forming a closed-loop feedback with the desired current. Simultaneously, it acquires speed and electrical angle data for speed loop regulation and space vector modulation. This system significantly improves dynamic response speed and low-speed stability while maintaining control accuracy, making it suitable for high-performance permanent magnet synchronous motor control applications such as electric vehicle drives, servo control, and industrial automation.

[0052] The following simulation verification of the dead zone compensation method for dead-zone predictive current control of permanent magnet synchronous motor provided by the present invention is carried out. In this embodiment, simulation experiments are conducted on traditional dead-zone predictive current control and dead-zone predictive current control based on the dead zone compensation method proposed in this invention: 1) The motor load torque is 0 before 0.04s, and the load torque jumps to 10Nm at 0.04s; 2) The motor speed loop adopts PI control, and the q-axis reference current is calculated in real time according to the difference between the reference speed and the actual speed, while the d-axis reference current is always 0.

[0053] Simulation test results are as follows Figure 3 and Figure 4 As shown: Figure 3 This figure compares the stator phase current test results of traditional deadbeat current predictive control (DPCC) modulation and the method proposed in this invention under steady-state conditions with a motor speed of 100 r / min and a load torque of 10 Nm. Figure 3 It can be seen that after adding the dead zone compensation module to the system, the sinusoidal nature of the three-phase current waveform of the permanent magnet synchronous motor is significantly improved, and the zero-current clamping phenomenon is greatly reduced.

[0054] Figure 4 This figure compares the stator phase current test results of traditional deadbeat current predictive control (DPCC) modulation and the method proposed in this invention under steady-state conditions of motor speed 500 r / min and load torque 10 Nm. Figure 4 It can be seen that dead zone compensation has a significant effect on suppressing current harmonics caused by dead zone. Moreover, the effect of dead zone compensation becomes smaller and smaller as the speed increases. This is because the impact of dead zone on the system decreases as the speed of the permanent magnet synchronous motor increases.

[0055] The steps of the various methods described above are only for clarity. In practice, they can be combined into one step or some steps can be split into multiple steps. As long as they include the same logical relationship, they are all within the protection scope of this invention. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, without changing the core design of the algorithm and process, are also within the protection scope of this invention.

[0056] Another embodiment of the present invention relates to a dead-zone compensation device for dead-zone predictive current control of a permanent magnet synchronous motor without deadbeat. The implementation details of this embodiment are described below. The following details are provided for ease of understanding and are not essential for implementing this solution. The dead-zone compensation device for dead-zone predictive current control of a permanent magnet synchronous motor in this embodiment includes: The model building module is used to build the motor model of the permanent magnet synchronous motor; The ideal voltage prediction module is used to obtain the ideal control voltage of the permanent magnet synchronous motor within one current sampling period based on the motor model and using the deadbeat current prediction control method. The disturbance voltage acquisition module is used to predict the changes in rotor flux linkage and stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle based on the operating status and motor parameters of the permanent magnet synchronous motor, so as to obtain the disturbance voltage generated by the permanent magnet synchronous motor due to the dead time. The disturbance voltage compensation module is used to superimpose the disturbance voltage with the ideal control voltage to obtain the target control voltage, and then drive the three-phase inverter of the permanent magnet synchronous motor through the target control voltage to control the operation of the permanent magnet synchronous motor.

[0057] It is not difficult to see that this embodiment is a device embodiment corresponding to the above method embodiments, and this embodiment can be implemented in conjunction with the above method embodiments. The relevant technical details and technical effects mentioned in the above embodiments are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the above embodiments.

[0058] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0059] Another embodiment of the present invention relates to a computer device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the dead-zone compensation method for deadbeat predictive current control of permanent magnet synchronous motors in the above embodiments.

[0060] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0061] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0062] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method embodiments described above.

[0063] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0064] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A dead-zone compensation method for dead-beat predictive current control of a permanent magnet synchronous motor, characterized in that, The method includes: Establish a motor model for the permanent magnet synchronous motor; Based on the motor model, the ideal control voltage of the permanent magnet synchronous motor within one current sampling period is predicted by the deadbeat current prediction control method. Based on the operating status and parameters of the permanent magnet synchronous motor, the rotor flux increment and the change in stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle are predicted by the motor model in order to obtain the disturbance voltage generated by the permanent magnet synchronous motor due to the dead time. The target control voltage is obtained by superimposing the disturbance voltage and the ideal control voltage, and the three-phase inverter of the permanent magnet synchronous motor is driven by the target control voltage to control the operation of the permanent magnet synchronous motor.

2. The dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor according to claim 1, characterized in that, The establishment of the motor model for the permanent magnet synchronous motor includes: A first motor model of a permanent magnet synchronous motor in a three-phase stationary abc coordinate system is established. The first motor model is transformed by Clarke and Park to obtain the second motor model in a two-phase rotating dq coordinate system.

3. The dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that, The second motor model consists of the voltage equation, torque equation, and flux linkage equation of a permanent magnet synchronous motor, which are as follows: ； ； The flux linkage equation is: ； In the formula, R For stator resistance, u d , u q , i d , i q They are dq Shaft voltage and stator current, L d and L q yes dq The stator inductance value of the shaft, ω e It is electric angular velocity. It is a permanent magnet flux chain. T e It is electromagnetic torque. n p It is an extreme logarithm. and This represents the components of the stator flux linkage along the d-axis and q-axis. L d and L q This represents the d-axis inductance and the q-axis inductance. It is a permanent magnet flux linkage.

4. The dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor according to claim 3, characterized in that, The disturbance voltage generated by the dead time of the permanent magnet synchronous motor is obtained through the following steps: Establish a stationary coordinate system Voltage equation for a permanent magnet synchronous motor: ； In the formula, u , u , i , i These are the stationary coordinate systems. Under voltage and stator current, L s It is the stator inductance value. The back electromotive force component; Obtain the actual voltage when the dead-time effect exists: ； In the formula, This is the dead zone equivalent disturbance voltage; The Park transformation yields the result in the rotating coordinate system. dq Compensation voltage under f d , f q : ； Combine a sampling period T i Current deviation values ​​of the perpendicular and direct axes in the internal rotating coordinate system: ； In the formula, i d , i q One sampling period T i Current deviation value along the direct axis in the internal rotating coordinate system. e d , e q The back electromotive force component along the dq axis; The formula for estimating the disturbance voltage is derived as follows: 。 5. The dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor according to claim 1, characterized in that, The step of obtaining the ideal control voltage of the permanent magnet synchronous motor within one current sampling period using the deadbeat current predictive control method based on the motor model includes: The voltage equation is subjected to first-order forward difference to obtain the predicted current expression of the permanent magnet synchronous motor at a certain moment, and the control voltage expression of the permanent magnet synchronous motor at a certain moment is determined based on the predicted current expression. The ideal control voltage of the permanent magnet synchronous motor within one current sampling period is obtained based on the control voltage expression.

6. The dead-zone compensation method for dead-time predictive current control of a permanent magnet synchronous motor according to claim 1, characterized in that, Prior to the three-phase inverter that drives the permanent magnet synchronous motor via the target control voltage, the following is also included: The target control voltage is low-pass filtered.

7. A dead-zone compensation device for dead-time predictive current control of a permanent magnet synchronous motor, characterized in that, The system includes: The model building module is used to build the motor model of the permanent magnet synchronous motor; The ideal voltage prediction module is used to obtain the ideal control voltage of the permanent magnet synchronous motor within one current sampling period based on the motor model and using the deadbeat current prediction control method. The disturbance voltage acquisition module is used to predict the changes in rotor flux linkage and stator-side induced electromotive force of the permanent magnet synchronous motor within one current sampling cycle based on the operating status and motor parameters of the permanent magnet synchronous motor, so as to obtain the disturbance voltage generated by the permanent magnet synchronous motor due to the dead time. The disturbance voltage compensation module is used to superimpose the disturbance voltage with the ideal control voltage to obtain the target control voltage, and then drive the three-phase inverter of the permanent magnet synchronous motor through the target control voltage to control the operation of the permanent magnet synchronous motor.

8. A computer device, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the dead-zone compensation method for dead-zone predictive current control of permanent magnet synchronous motors as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the dead zone compensation method for dead-time predictive current control of permanent magnet synchronous motor as described in any one of claims 1 to 6.

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