Motor bus voltage adaptive control method, device and motor system

Abstract

This application relates to the field of motor control technology and discloses a method, device, and motor system for adaptive control of motor bus voltage. The method includes: determining an initial voltage reference value based on the current operating state of the motor; optimizing the voltage margin and determining a target voltage reference value based on the optimized voltage margin and the initial voltage reference value; determining a voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and determining a reference value for the inductor current of the voltage conversion circuit based on the voltage tracking error; and performing deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, so that the bus voltage converges to the target voltage reference value. This application significantly improves the bus voltage utilization rate and modulation ratio, and significantly enhances the operational reliability and lifespan of the motor system.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a method, device and motor system for adaptive control of motor bus voltage. Background Technology

[0002] Magnetically suspended turbulent molecular pumps (MSTMPs) are widely used in semiconductor manufacturing, precision vacuum systems, and high-end scientific instruments. They extensively employ high-power-density, low-inductance permanent magnet synchronous motors (PMSMs). In related technologies, a three-phase voltage source inverter with a fixed DC bus voltage is typically used in conjunction with space vector pulse width modulation (SVPWM) to drive the motor.

[0003] However, as systems develop towards miniaturization and high speed, motors are gradually adopting low inductance designs, making them sensitive to high-frequency voltage components. Using related technologies for motor drive results in significant high-frequency harmonic current, leading to increased motor losses and excessively rapid temperature rise, which seriously affects the reliability of motor system operation. Summary of the Invention

[0004] This application provides a method, device, and motor system for adaptive control of motor bus voltage, which solves the technical problems of significant high-frequency harmonics in current motor drives, leading to increased motor losses and excessively rapid temperature rise. It adopts a method of dynamically adjusting the bus voltage to reduce the current harmonic content, and combines deadbeat predictive control to ensure that the bus voltage can respond instantaneously to changes in speed or load, thereby significantly improving the bus voltage utilization rate and modulation ratio, and significantly enhancing the reliability and lifespan of the motor system.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, this application provides a method for adaptive control of motor bus voltage, wherein a voltage conversion circuit is connected between the motor and an input power supply, and the voltage conversion circuit outputs bus voltage to the motor; the method includes: Determine the initial voltage reference value based on the current operating status of the motor; The voltage margin used to compensate for the initial voltage reference value is optimized, and the target voltage reference value is determined based on the optimized voltage margin and the initial voltage reference value. The voltage tracking error is determined based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and the inductor current reference value of the voltage conversion circuit is determined based on the voltage tracking error. Based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, the voltage conversion circuit is subjected to deadbeat current control, so that the bus voltage converges to the target voltage reference value.

[0006] This application proposes an adaptive control method for motor bus voltage. It generates an optimal bus voltage reference value through upper-level decision-making and combines this with lower-level deadbeat current control to achieve high-speed and accurate tracking of dynamic voltage. Furthermore, it utilizes a voltage conversion circuit to dynamically adjust the bus voltage, reducing unnecessary bus voltage margin and increasing the modulation ratio. Compared to related technologies using PI control, this application employs deadbeat current control to effectively eliminate phase lag, ensuring the bus voltage can respond instantaneously to changes in speed or load. This makes the inverter output voltage closer to an ideal sine wave, thereby reducing current harmonic content, effectively reducing additional losses, and contributing to lower motor temperature rise and improved system reliability and lifespan. Moreover, compared to related technologies, this application suppresses harmonic generation at its source, reducing conducted and radiated interference, thus minimizing the impact on the magnetic levitation bearing control system and improving the stability and accuracy of levitation control.

[0007] Optionally, determining the initial voltage reference value based on the current operating state of the motor includes: Obtain the d-axis voltage component and q-axis voltage component of the field-oriented control output under the current operating state of the motor; The initial voltage reference value is determined based on the d-axis voltage component, the q-axis voltage component, and the preset distortion-free constraint condition of the space vector pulse width modulation.

[0008] Optionally, optimizing the voltage margin used to compensate the initial voltage reference value includes: A preset disturbance signal is generated, and the voltage margin is optimized based on the preset disturbance signal and the dynamic optimization algorithm.

[0009] This application generates a preset disturbance signal and optimizes the voltage margin based on a dynamic optimization algorithm. It can automatically search online for the optimal value that balances the voltage margin and modulation saturation, thereby suppressing harmonics and avoiding modulation saturation, and achieving synergistic optimization of efficiency and modulation performance.

[0010] Optionally, when the dynamic optimization algorithm is an extreme value search algorithm, the step of optimizing the voltage margin based on the preset disturbance signal and the dynamic optimization algorithm includes: Construct a cost function, wherein the cost function characterizes the sum of the voltage margin and the preset cost term, wherein the voltage margin includes a reference margin and the preset disturbance signal; The estimated gradient of the cost function in response to the preset disturbance signal is obtained, and the baseline margin is updated according to the estimated gradient until the cost function reaches the preset convergence condition. The optimized voltage margin is determined according to the updated baseline margin and the preset disturbance signal.

[0011] This application uses extreme value search optimization to determine in real time the voltage margin that can balance efficiency and modulation saturation. The voltage margin obtained in this way can suppress harmonics without causing modulation saturation.

[0012] Optionally, determining the target voltage reference value based on the optimized voltage margin and the initial voltage reference value includes: The target voltage reference value is determined by adding the initial voltage reference value and the voltage margin obtained through optimization.

[0013] This application determines the target voltage reference value that satisfies the space vector pulse width modulation constraint and takes into account system efficiency by adding the initial voltage reference value to the voltage margin obtained through optimization. This allows the target voltage reference value to not only respond quickly to changes in motor operating conditions, but also to autonomously optimize to the optimal bus voltage operating point that balances efficiency and performance.

[0014] Optionally, determining the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and determining the inductor current reference value of the voltage conversion circuit based on the voltage tracking error, includes: The voltage tracking error is determined based on the difference between the target voltage reference value and the bus voltage. The inductor current reference value is determined by the proportional-integral controller based on the voltage tracking error.

[0015] This application forms a closed-loop voltage control by comparing the difference between the target voltage reference value and the bus voltage. Then, the proportional-integral controller generates an inductor current reference value based on the voltage tracking error, providing an accurate command signal for subsequent control of the voltage converter based on the inductor current reference value.

[0016] Optionally, the step of performing deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply includes: A state discrete model of the voltage conversion circuit is determined, which characterizes the mapping relationship between the current inductor current, the bus voltage, the duty cycle, the inductor current and the input voltage in the current motor control cycle; The inductor current reference value is used as the inductor current of the voltage conversion circuit in the next motor control cycle and substituted into the mapping relationship. The duty cycle is then solved by combining the current inductor current, the bus voltage, and the input voltage of the voltage conversion circuit in the current motor control cycle. Based on the solution results and preset duty cycle constraints, the target duty cycle of the voltage conversion circuit in the current motor control cycle is determined, so as to perform deadbeat current control on the voltage conversion circuit according to the target duty cycle.

[0017] This application determines the state discrete model of the voltage conversion circuit, substitutes the inductor current reference value into the model to obtain the duty cycle of the voltage conversion circuit corresponding to the current motor control cycle, realizes the rapid and accurate tracking of the target voltage reference value, eliminates the phase lag of traditional proportional-integral control, and improves the dynamic response speed of the bus voltage.

[0018] Optionally, the voltage conversion circuit includes any one of a Buck converter, a Buck-Boost converter, and a Z-source inverter.

[0019] Secondly, this application provides a motor bus voltage adaptive control device, wherein a voltage conversion circuit is connected between the motor and the input power supply, and the voltage conversion circuit outputs a bus voltage to the motor. The device includes: The reference voltage initialization module is used to determine the initial voltage reference value based on the current operating state of the motor. The reference voltage optimization module is used to optimize the voltage margin used to compensate the initial voltage reference value, and to determine the target voltage reference value based on the optimized voltage margin and the initial voltage reference value. The voltage control loop module is used to determine the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and to determine the inductor current reference value of the voltage conversion circuit based on the voltage tracking error. The current control loop module is used to perform deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, so that the bus voltage converges to the target voltage reference value.

[0020] Thirdly, this application provides a motor system, the system comprising: Electric motor; Input power; Voltage conversion circuit; And the motor bus voltage adaptive control device as described above, wherein the input terminal of the voltage conversion circuit is connected to the input power supply, the output terminal of the voltage conversion circuit is connected to the motor, and the adaptive control device is connected to the control terminal of the voltage conversion circuit to adaptively control the bus voltage output by the voltage conversion circuit. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the motor system topology of PMSM in related technologies; Figure 2 This is a schematic diagram of the motor system topology of the PMSM in the embodiments of this application; Figure 3 One of the flowcharts for an adaptive control method for motor bus voltage provided in this application embodiment; Figure 4 This is a schematic diagram of the control system topology of the PMSM in the embodiments of this application; Figure 5 A second schematic flowchart illustrating an adaptive control method for motor bus voltage provided in this application embodiment; Figure 6 The third schematic flowchart of an adaptive control method for motor bus voltage provided in this application embodiment; Figure 7 The fourth flowchart illustrates a motor bus voltage adaptive control method provided in this application embodiment; Figure 8 Fifth of a flowchart illustrating an adaptive control method for motor bus voltage provided in this application embodiment; Figure 9 This is a schematic diagram of the structure of a motor bus voltage adaptive control device provided in an embodiment of this application; Figure 10 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0025] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0026] In fields such as semiconductor manufacturing and precision vacuum systems, magnetic levitation molecular pumps widely use permanent magnet synchronous motors with high power density and low inductance, which have extremely high requirements for the stability, low vibration and low temperature rise of the drive system.

[0027] PMSMs typically use a three-phase voltage source inverter with a fixed DC bus voltage in conjunction with SVPWM to drive the permanent magnet synchronous motor. Figure 1 The motor system topology of the PMSM is shown, such as... Figure 1 As shown, the PMSM acts as a load connected to the input power supply via a three-phase inverter, and the input power supply provides a DC voltage. The input is a three-phase inverter, which then uses Field Oriented Control (FOC) to adjust the inverter's switching duty cycle according to the real-time speed and load, thereby generating a three-phase AC voltage as the bus voltage input to the PMSM.

[0028] However, as systems evolve towards miniaturization and higher speeds, motor designs tend towards low-inductance structures. The extremely small inductance results in weak energy storage and filtering capabilities, making them highly sensitive to voltage transients generated by PWM. During normal operation, especially under non-maximum speed conditions, the fixed bus voltage causes an excessively low modulation ratio, resulting in the inverter's output voltage vector pulse being far greater than the actual requirement, thus generating significant high-frequency current harmonics.

[0029] In some related technologies, harmonic compensation methods such as PIR and ADRC mainly target low-frequency characteristic harmonics such as the 5th and 7th harmonics, and have limited effectiveness in suppressing broadband high-frequency harmonics near the switching frequency. Other related technologies employ Model Predictive Control (MPC), which is computationally complex and difficult to implement on low-cost hardware platforms, while suppressing harmonics by increasing the switching frequency leads to a significant increase in switching losses.

[0030] It is evident that high-power-density, low-inductance PMSMs are prone to generating high-frequency current harmonics under conventional high-frequency PWM drive, which leads to increased motor losses, higher temperature rise, enhanced torque pulsation, and interference with the stability of the magnetic levitation bearing system.

[0031] To address the aforementioned issues, this application provides a method for adaptive control of motor bus voltage, which can be used in precision motor systems such as magnetic levitation molecular pumps. Figure 2 The motor system topology of the PMSM in this embodiment is shown, such as... Figure 2 As shown, a voltage conversion circuit is connected between the PMSM and the input power supply, and the voltage conversion circuit outputs bus voltage to the motor. The voltage conversion circuit includes any one of a Buck converter, a Buck-Boost converter, and a Z-source inverter, and provides bus voltage to the motor through the inverter. In this embodiment, a Buck converter is used as an example of the voltage conversion circuit and is not intended to limit this application.

[0032] Furthermore, Figure 3 The flowchart of the above-described adaptive control method for motor bus voltage in some embodiments of this application is shown, such as... Figure 3 As shown, the method includes the following steps: Step S1: Determine the initial voltage reference value based on the current operating status of the motor.

[0033] Specifically, in a motor control system, the operating state of a motor is determined by factors such as its speed and load torque, which are ultimately reflected in the voltage command output by the FOC algorithm. Figure 4The diagram shows the control system topology of the PMSM in this embodiment of the application. Combined with the FOC algorithm, it can be seen that the rotor position signal of the motor is first obtained by the rotor position observer. The actual electric angular velocity of the motor is obtained through differential calculation. Its relationship with the given speed signal The comparison is then input to the speed loop controller. The speed loop controller outputs the q-axis current command. Meanwhile, the three-phase stator current , and The sampled signal input undergoes Clarke transform to obtain the current component in the stationary coordinate system. and Then... and Current components converted to a rotating coordinate system and Then, the current components are... With d-axis current command Comparison results and current components With q-axis current command The comparison result is input to the current loop controller, where, Typically, the value is set to 0. Finally, the voltage component output by the current loop controller... and Determine the above initial voltage reference value This provides an accurate voltage basis for subsequent voltage optimization, which facilitates improving the subsequent control response speed.

[0034] It should be noted that in some embodiments of this application, the initial voltage reference value... It represents the bus voltage value that satisfies the SVPWM no-distortion constraint, ensuring that the inverter output voltage waveform is not distorted.

[0035] Step S3: Optimize the voltage margin used to compensate for the initial voltage reference value, and determine the target voltage reference value based on the optimized voltage margin and the initial voltage reference value.

[0036] Specifically, due to the initial voltage reference value While the initial voltage reference value is theoretically optimal, in reality, the system suffers from non-ideal factors such as parameter errors and noise. To ensure the robustness of the target voltage reference value, the embodiments of this application use an initial voltage reference value... Provides a dynamically adjustable voltage margin. Among them, the voltage margin is optimized through an online optimization algorithm. Perform adaptive search, and then optimize the voltage margin. Compared with the initial voltage reference value Adding them together yields the target voltage reference value. This value serves as the command input for subsequent bus voltage regulation, enabling adjustments based on the target voltage reference value. Adjust the bus voltage output of the voltage conversion circuit It can reduce as much as possible while meeting the requirements of the modulation linear region, thereby suppressing high-frequency current harmonics and helping to achieve a balance between efficiency and dynamic performance.

[0037] Step S5: Determine the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and determine the inductor current reference value of the voltage conversion circuit based on the voltage tracking error.

[0038] Target voltage reference value Once determined, the actual bus voltage needs to quickly follow the command. For example... Figure 4 As shown, the cascaded control loop includes an outer loop, where the objective of the outer loop is to reduce the bus voltage. Accurately track target voltage reference value In this embodiment, the outer loop is responsible for setting the inductor current target. Specifically, the outer loop sets the target voltage reference value. and the bus voltage fed back by the voltage conversion circuit Determine voltage tracking error Based on voltage tracking error Generate inductor current reference value This provides precise input commands for subsequent deadbeat current control.

[0039] Step S7: Based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, perform deadbeat current control on the voltage conversion circuit to make the bus voltage converge towards the target voltage reference value.

[0040] Specifically, Figure 4 The cascaded control loop shown also includes an inner loop, the objective of which is based on the inductor current reference value generated by the outer loop. To achieve single-cycle deadbeat control of the duty cycle of the voltage conversion circuit, this embodiment is responsible for eliminating phase lag and ensuring that the inductor current tracks the command in real time. Optionally, a discrete state model of the voltage conversion circuit is first determined. This model establishes a mapping relationship between state variables such as inductor current, bus voltage, and duty cycle. Then, the inner loop substitutes the inductor current reference value into this mapping relationship to obtain the duty cycle of the voltage conversion circuit in the current motor control cycle. Therefore, based on the duty cycle Adjust the switching frequency of the current motor control cycle according to the situation, so that the output voltage of the voltage conversion circuit is directed towards the target voltage reference value. Convergence enables rapid and accurate tracking of the target voltage.

[0041] This application proposes an adaptive control method for motor bus voltage. It generates an optimal bus voltage reference value through upper-level decision-making and combines this with lower-level deadbeat current control to achieve high-speed and accurate tracking of dynamic voltage. Furthermore, it utilizes a voltage conversion circuit to dynamically adjust the bus voltage, reducing unnecessary bus voltage margin and increasing the modulation ratio. Compared to related technologies using PI control, this application employs deadbeat current control to effectively eliminate phase lag, ensuring the bus voltage can instantly respond to changes in speed or load. This makes the inverter output voltage closer to an ideal sine wave, thereby reducing current harmonic content, effectively reducing additional losses, and contributing to lower motor temperature rise and improved system reliability and lifespan. Moreover, compared to related technologies, this application suppresses harmonic generation at the source, reducing conducted and radiated interference, thus reducing the impact on the magnetic levitation bearing control system and improving the stability and accuracy of levitation control.

[0042] Figure 5 A flowchart of step S1 above is shown, as follows: Figure 5 As shown, in some embodiments of this application, step S1 may include the following steps: Step S11: Obtain the d-axis voltage component and q-axis voltage component of the field-oriented control output under the current operating state of the motor; Step S13: Determine the initial voltage reference value based on the preset distortion-free constraint conditions of the d-axis voltage component, the q-axis voltage component, and the space vector pulse width modulation.

[0043] Specifically, during motor operation, the FOC algorithm outputs the d-axis voltage components in the rotating coordinate system based on the adjustment results of the speed loop and current loop. and q-axis voltage component Therefore, the initial voltage reference value is determined based on the following formula (1): Understandably, formula (1) represents Satisfy the SVPWM distortion-free constraint.

[0044] In some embodiments of this application, step S3 may include: generating a preset disturbance signal, optimizing the voltage margin based on the preset disturbance signal and a dynamic optimization algorithm, and then determining the target voltage reference value based on the sum of the initial voltage reference value and the optimized voltage margin.

[0045] Specifically, the initial voltage reference value ensures that the bus voltage can meet the basic voltage requirements of the motor under the current operating conditions, while the optimized voltage margin is used as a dynamic compensation term to adjust the bus voltage online to balance the optimal trade-off between harmonic suppression and modulation safety.

[0046] In this embodiment of the application, the preset perturbation signal is a high-frequency sinusoidal perturbation signal, and the discretization formula of the preset perturbation signal is shown in the following formula (2): In the formula, This represents the preset disturbance signal in the k-th motor control cycle. To preset the disturbance amplitude, To preset the perturbation frequency, This refers to the motor control cycle time.

[0047] Therefore, the aforementioned voltage margin It consists of a gradually varying reference margin and a preset disturbance signal. Composition, namely voltage margin As shown in the following formula (3): In the formula, This represents the voltage margin in the k-th motor control cycle. This represents the baseline margin during the (k-1)th motor control cycle.

[0048] Therefore, in this embodiment, a preset disturbance signal is superimposed on the voltage margin of the previous motor control cycle to excite the system to produce an observable response change. Then, the dynamic optimization algorithm analyzes the disturbance response based on the system performance index to determine the direction and degree of deviation of the voltage margin from the optimal value under the current motor control cycle, thereby realizing the dynamic optimization of the voltage margin.

[0049] Optionally, embodiments of this application employ dynamic optimization algorithms such as Extremum Seeking Control (ESC), Look-Up Table (LUT), Particle Swarm Optimization (PSO), and reinforcement learning. Among these, the Look-Up Table, PSO, and reinforcement learning are more dependent on motor parameters than slow optimization algorithms.

[0050] This application embodiment generates a preset disturbance signal and optimizes the voltage margin based on a dynamic optimization algorithm. It can automatically search online for the optimal value that balances the voltage margin and modulation saturation. While suppressing harmonics, it avoids modulation saturation and achieves synergistic optimization of efficiency and modulation performance. As a result, the target voltage reference value obtained by adding the initial voltage reference value and the optimized voltage margin can not only respond quickly to changes in motor operating conditions, but also autonomously optimize to the best bus voltage operating point that balances efficiency and performance.

[0051] Furthermore, when the dynamic optimization algorithm is an extreme value search algorithm, Figure 6 A flowchart of step S3 above is shown, as follows: Figure 6 As shown, step S3 above may include the following steps: Step S31: Construct a cost function, wherein the cost function represents the sum of the voltage margin and the preset cost term, wherein the voltage margin includes the reference margin and the preset disturbance signal.

[0052] Specifically, the constructed cost function As shown in the following formula (4): In the formula, For the preset cost item, Here are the weighting coefficients for the preset cost terms, where, The efficiency is represented by a lower voltage, which is better. In some embodiments of this application, the preset cost term is a modulation saturation penalty term, which increases when the modulation ratio approaches the saturation region, forcing the optimization process to avoid entering the overmodulation region. In other embodiments of this application, the cost term can also be set based on the current THD sampling value, but this method requires additional signal processing circuitry.

[0053] It should be noted that at the perturbation frequency When the system response is low and approximately linear, the cost function can be approximated by the following formula (5): In the formula, This represents the approximate cost function. The DC component of the cost function when the disturbance amplitude is zero. Gradient and = , For noise and disturbances at other frequencies, etc.

[0054] Step S33: Obtain the estimated gradient of the cost function in response to the preset disturbance signal, and update the reference margin according to the estimated gradient until the cost function reaches the preset convergence condition. Determine the optimized voltage margin according to the updated reference margin and the preset disturbance signal.

[0055] Specifically, after superimposing a preset disturbance signal with a known frequency and amplitude onto the baseline margin, the preset disturbance signal will cause corresponding fluctuations in the cost function. By performing bandpass filtering, multiplication demodulation, and low-pass filtering on the fluctuation signal of J, the estimated gradient can be extracted, and the baseline margin can be updated in the direction of the estimated gradient descent, so that the cost function reaches the preset convergence condition.

[0056] In some embodiments of this application, in order to... The gradient g information can be accurately extracted from the response through a three-step simultaneous demodulation process: standard bandpass filtering, phase-sensitive demodulation (multiplication operation), and low-pass filtering.

[0057] First of all, A high-pass filter (HPF) is applied to remove DC bias and irrelevant frequency noise, resulting in a cost function that contains only fundamental frequency information. As shown in the following formula (6): In the formula, After filtering The phase delay relative to the original signal before filtering.

[0058] Then, Multiplying the signal by a reference signal that is in phase and frequency with the preset disturbance signal yields the function component shown in formula (7) below. for: Function components The DC component proportional to the gradient g can be accurately extracted using a narrowband low-pass filter. As shown in the following formula (8): In particular, because the frequency of the high-frequency disturbance signal injected into the voltage margin during ESC is much lower than the system bandwidth, the phase delay caused by this disturbance is very small. It can be approximated as 1.

[0059] This application embodiment uses a discrete integrator to implement gradient descent, and updates the baseline margin according to the extracted gradient information as shown in the following formula (9): In the formula, For the updated baseline margin, This is the baseline margin before the update. For integral gain. Under the action of formula (9), when When the value is positive, it indicates that the baseline margin is too high, causing the updated baseline margin to decrease; conversely, it increases until... It converges to zero, that is, it reaches the minimum point of the cost function.

[0060] Based on the updated baseline margin Superimposed preset disturbance signal p To achieve voltage margin The optimization update. Furthermore, the target voltage reference value consists of two parts: the initial voltage reference value and the voltage margin obtained through optimization. That is, the target voltage reference value is obtained from the above formulas (1) and (9) as shown in the following formula (10): The embodiments of this application employ extreme value search optimization to determine in real time the voltage margin that can balance efficiency and modulation saturation. The voltage margin obtained in this way can suppress harmonics without causing modulation saturation.

[0061] Figure 7 A flowchart of step S5 above is shown, as follows: Figure 7 As shown, in some embodiments of this application, step S5 may include the following steps: Step S51: Determine the voltage tracking error based on the difference between the target voltage reference value and the bus voltage.

[0062] Specifically, such as Figure 4 As shown, the output voltage of the voltage conversion circuit As the bus voltage is fed forward, the voltage tracking error is determined according to the following formula (11): In the formula, Let be the voltage tracking error in the k-th motor control cycle. This is the target voltage reference value for the k-th motor control cycle. This represents the bus voltage during the kth motor control cycle.

[0063] Step S53: Determine the reference value of the inductor current based on the voltage tracking error using a proportional-integral controller.

[0064] Specifically, such as Figure 4 As shown, the generated voltage tracking error feedback input is the outer loop in the cascaded control loop, i.e., the voltage loop. Using the discrete PI controller of this voltage loop, the inductor current reference value required to generate the inner loop is determined based on the voltage tracking error, as shown in the following formula (12): In the formula, This is the reference value for the inductor current during the k-th motor control cycle. This is the proportional gain of the voltage loop. This is the integral gain of the voltage loop.

[0065] This application embodiment forms a closed-loop voltage control by comparing the difference between the target voltage reference value and the bus voltage. Then, the proportional-integral controller generates an inductor current reference value based on the voltage tracking error, providing an accurate command signal for subsequent control of the voltage converter based on the inductor current reference value.

[0066] This application embodiment determines the duty cycle of the voltage conversion circuit based on the aforementioned inductor current reference value. Related technologies generally employ traditional PI control or hysteresis control methods. However, due to issues such as response lag and limited adjustment bandwidth, these methods easily lead to bus voltage tracking errors, thereby limiting the inverter modulation ratio, causing modulation distortion and high-frequency current harmonics, ultimately affecting system performance and motor control stability. Therefore, this application embodiment uses the CDPC control algorithm to achieve dynamic voltage tracking.

[0067] Figure 8 A flowchart of step S7 above is shown, as follows: Figure 8 As shown, in some embodiments of this application, step S7 may include the following steps: Step S71: Determine the state discrete model of the voltage conversion circuit. The state discrete model represents the mapping relationship between the current inductor current, bus voltage, duty cycle of the voltage conversion circuit in the current motor control cycle, the inductor current in the next motor control cycle, and the input voltage.

[0068] Specifically, in this embodiment of the application, a Buck converter is used as a voltage conversion circuit as an example. The state equation of the Buck converter is discretized as shown in the following formula (13): In the formula, and These are the bus voltages under the k-th and (k+1)-th motor control cycles, respectively. and These are the inductor currents in the k-th and (k+1)-th motor control cycles, respectively. This refers to the output filter inductance value of the Buck converter. This refers to the capacitance value of the Buck converter. This refers to the load current of the Buck converter. Input voltage, Let be the duty cycle of the Buck converter during the k-th motor control cycle.

[0069] Therefore, the mapping relationship between the current inductor current, bus voltage, duty cycle, inductor current and input voltage of the Buck converter in the current motor control cycle can be determined by the above formula (13).

[0070] Step S73: Substitute the inductor current reference value as the inductor current of the voltage conversion circuit in the mapping relationship, and combine the current inductor current, bus voltage and input voltage of the voltage conversion circuit in the current motor control cycle to solve the duty cycle.

[0071] Specifically, such as Figure 4 As shown, the inductor current of the Buck converter during the current motor control cycle. The inner loop in the feedback input cascaded control loop is the current loop. In this embodiment, the goal of the current loop is to control the inductor current. The single-cycle deadbeat control, that is, applying a duty cycle D(k) in the k-th cycle, such that in the k+1-th cycle, Equal to the reference value given by the outer ring That is, .

[0072] Furthermore, Substituting the mapping relationship shown in the above formula (13), the predicted expression for the inductor current is obtained as shown in the following formula (14): Thus, the duty cycle D(k) is obtained by inverse solution as shown in the following formula (15): Substituting the above formula (12) into formula (15), the result of calculating the duty cycle of the buck converter in the current motor control cycle is shown in the following formula (16): Step S75: Determine the target duty cycle of the voltage conversion circuit in the current motor control cycle based on the solution results and preset duty cycle constraints, so as to perform deadbeat current control on the voltage conversion circuit according to the target duty cycle.

[0073] Specifically, to ensure stable system operation and take into account hardware switching timing constraints, this embodiment of the application performs a limiting process on the actual duty cycle applied to the Buck converter, and then determines the target duty cycle according to the following formula (17): In the formula, and These are the minimum and maximum limits for the output duty cycle, respectively, which can be set according to system parameters and dead time, among other factors.

[0074] This application embodiment determines the state discrete model of the voltage conversion circuit, substitutes the inductor current reference value into the model to obtain the duty cycle of the voltage conversion circuit corresponding to the current motor control cycle, realizes fast and accurate tracking of the target voltage reference value, eliminates the phase lag of traditional proportional-integral control, and improves the dynamic response speed of the bus voltage.

[0075] Therefore, this application's embodiments first address the problem of small inductor motors being sensitive to high-frequency voltage components due to their small armature inductance, resulting in significant high-frequency harmonics in the current. A method of dynamically adjusting the bus voltage is employed. By reducing unnecessary bus voltage margins and increasing the modulation ratio, the inverter output voltage is made closer to an ideal sine wave, thereby weakening high-frequency current components and reducing current harmonic components. This effectively reduces additional losses such as copper and iron losses caused by harmonics, improving overall system efficiency, reducing motor temperature rise, and enhancing system reliability and lifespan. Furthermore, this application's embodiments address the electromagnetic interference problem caused by high-frequency harmonics by suppressing harmonic generation at its source, reducing conducted and radiated interference, thereby reducing the impact on the magnetic levitation bearing control system and improving the stability and accuracy of levitation control.

[0076] Secondly, addressing the issues of low utilization rate and limited modulation ratio of the fixed bus voltage, this application's embodiments achieve dynamic adjustment of the bus voltage by connecting a single-stage Buck converter and other voltage conversion circuits in series at the front end of a traditional three-phase voltage source inverter, and generating the minimum necessary voltage using SVPWM constraints. Simultaneously, optimal voltage margin configuration is achieved through online optimization using ESC, automatically finding the optimal reference voltage value for the bus voltage that suppresses harmonics without causing modulation saturation. Combined with Cascaded Deadbeat Predictive Control (CDPC), the phase lag of traditional PI control is eliminated, ensuring that the bus voltage can respond instantaneously to changes in speed or load, thereby significantly improving bus voltage utilization and modulation ratio.

[0077] It is worth noting that the PI control and other methods used in the relevant technologies are error-based feedback control. Their working logic involves detecting the error, calculating the control input, applying the control, and waiting for the next cycle to detect the error, resulting in a significant lag in the control response. Specifically, the controller samples the output voltage at the beginning of each discrete control cycle and compares it with a voltage reference value to obtain the error. This means that the control action is based on the state at the end of the previous cycle, rather than the actual demand at the current moment.

[0078] Meanwhile, the new duty cycle calculated by the PI controller needs to be applied within the current cycle. However, due to the physical characteristics of voltage conversion circuits such as Buck circuits, where the inductor current and capacitor voltage cannot change abruptly, the output voltage needs to go through multiple switching cycles to track the command value, resulting in a significant calculation and execution lag. Furthermore, the integral term in PI control achieves adjustment by accumulating errors, and its output relative error change lags, introducing additional phase delay during dynamic adjustment, making it difficult to meet the control requirements for high-speed and high-precision tracking of bus voltage.

[0079] Deadbeat control is a model-based predictive control. Its core idea is to accurately calculate the control quantity required to eliminate the error in the next cycle based on the current state and system model. The control objective is not to reduce the error, but to directly set the target value for the next cycle. Substituting the target into the predictive model, the duty cycle required for the current cycle is solved. In this embodiment, the CDPC algorithm is implemented based on the discretized model of the voltage conversion circuit. Based on the model represented by the above formula (13), the current inductor current in the next cycle after applying the duty cycle can be accurately predicted based on the current inductor current, the current bus voltage, the input voltage, the filter inductor, and the motor control cycle. The current inner loop adopts deadbeat control, which is responsible for achieving single-cycle accurate tracking of the inductor current and fundamentally eliminating phase lag. The voltage outer loop adopts a PI controller, which only needs to output the inductor current reference value based on the voltage error and does not require high-speed dynamic response. Even if there is a slight lag in the outer loop, the inner current loop can quickly execute the tracking command, making the phase lag of the overall bus voltage tracking much smaller than that of the traditional dual-loop PI control structure, thus avoiding the defect of the voltage loop and current loop lags superimposed and coupled in the traditional structure.

[0080] Furthermore, the embodiments of this application employ a strategy based on extreme value search to optimize the target voltage reference value and cascaded deadbeat predictive control, which significantly reduces computational complexity while ensuring optimization performance and is suitable for low-cost control platforms such as DSPs.

[0081] Accordingly, please refer to Figure 9 This application also provides a motor bus voltage adaptive control device, wherein a voltage conversion circuit is connected between the motor and the input power supply, and the voltage conversion circuit outputs the bus voltage to the motor. The device includes: The reference voltage initialization module 100 is used to determine the initial voltage reference value according to the current operating state of the motor. For details, please refer to step S1. The reference voltage optimization module 200 is used to optimize the voltage margin used to compensate the initial voltage reference value, and to determine the target voltage reference value based on the optimized voltage margin and the initial voltage reference value. For details, please refer to step S3. The voltage control loop module 300 is used to determine the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and to determine the inductor current reference value of the voltage conversion circuit based on the voltage tracking error. For details, please refer to step S5. The current control loop module 400 is used to perform deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, so that the bus voltage converges to the target voltage reference value. For details, please refer to step S7.

[0082] The specific configurations and further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0083] The motor bus voltage adaptive control device provided in this application generates an optimal bus voltage reference value through upper-level decision-making and combines it with lower-level deadbeat current control to achieve high-speed and accurate tracking of dynamic voltage. It then uses a voltage conversion circuit to dynamically adjust the bus voltage, reducing unnecessary bus voltage margin and increasing the modulation ratio. Compared with related technologies using PI control, this application's deadbeat current control effectively eliminates phase lag, ensuring the bus voltage can instantly respond to changes in speed or load. This makes the inverter output voltage closer to an ideal sine wave, thereby reducing current harmonic content, effectively reducing additional losses, and helping to reduce motor temperature rise and improve system reliability and lifespan. Furthermore, compared with related technologies, this application suppresses harmonic generation at the source, reducing conducted and radiated interference, thus reducing the impact on the magnetic levitation bearing control system and improving the stability and accuracy of levitation control.

[0084] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0085] Accordingly, embodiments of this application also provide a motor system, the system comprising: Electric motor; Input power; Voltage conversion circuit; And the motor bus voltage adaptive control device as described above, wherein the input terminal of the voltage conversion circuit is connected to the input power supply, the output terminal of the voltage conversion circuit is connected to the motor, and the adaptive control device is connected to the control terminal of the voltage conversion circuit to adaptively control the bus voltage output by the voltage conversion circuit.

[0086] Please see Figure 10 , Figure 10 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application, such as... Figure 10As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 10 Take a processor 10 as an example.

[0087] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0088] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0089] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0090] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0091] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0092] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0093] This application provides a computer program product including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the method of any embodiment of this application.

[0094] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

[0095] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0096] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0097] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0098] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for adaptive control of motor bus voltage, characterized in that, A voltage conversion circuit is connected between the motor and the input power supply, and the voltage conversion circuit outputs a bus voltage to the motor. The method includes: Determine the initial voltage reference value based on the current operating status of the motor; The voltage margin used to compensate for the initial voltage reference value is optimized, and the target voltage reference value is determined based on the optimized voltage margin and the initial voltage reference value. The voltage tracking error is determined based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and the inductor current reference value of the voltage conversion circuit is determined based on the voltage tracking error. Based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, the voltage conversion circuit is subjected to deadbeat current control so that the bus voltage converges to the target voltage reference value. The step of determining the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and determining the inductor current reference value of the voltage conversion circuit based on the voltage tracking error, includes: The voltage tracking error is determined based on the difference between the target voltage reference value and the bus voltage. The inductor current reference value is determined by a proportional-integral controller based on the voltage tracking error. The step of performing deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply includes: A state discrete model of the voltage conversion circuit is determined, which characterizes the mapping relationship between the current inductor current, the bus voltage, the duty cycle, the inductor current and the input voltage in the current motor control cycle; The inductor current reference value is used as the inductor current of the voltage conversion circuit in the next motor control cycle and substituted into the mapping relationship. The duty cycle is then solved by combining the current inductor current, the bus voltage, and the input voltage of the voltage conversion circuit in the current motor control cycle. Based on the solution results and preset duty cycle constraints, the target duty cycle of the voltage conversion circuit in the current motor control cycle is determined, so as to perform deadbeat current control on the voltage conversion circuit according to the target duty cycle.

2. The adaptive control method for motor bus voltage according to claim 1, characterized in that, Determining the initial voltage reference value based on the current operating state of the motor includes: Obtain the d-axis voltage component and q-axis voltage component of the field-oriented control output under the current operating state of the motor; The initial voltage reference value is determined based on the d-axis voltage component, the q-axis voltage component, and the preset distortion-free constraint condition of the space vector pulse width modulation.

3. The adaptive control method for motor bus voltage according to claim 1, characterized in that, The optimization of the voltage margin used to compensate for the initial voltage reference value includes: A preset disturbance signal is generated, and the voltage margin is optimized based on the preset disturbance signal and the dynamic optimization algorithm.

4. The adaptive control method for motor bus voltage according to claim 3, characterized in that, When the dynamic optimization algorithm is an extreme value search algorithm, the optimization of the voltage margin based on the preset disturbance signal and the dynamic optimization algorithm includes: Construct a cost function, wherein the cost function characterizes the sum of the voltage margin and the preset cost term, wherein the voltage margin includes a reference margin and the preset disturbance signal; The estimated gradient of the cost function in response to the preset disturbance signal is obtained, and the baseline margin is updated according to the estimated gradient until the cost function reaches the preset convergence condition. The optimized voltage margin is determined according to the updated baseline margin and the preset disturbance signal.

5. The adaptive control method for motor bus voltage according to claim 1, characterized in that, The step of determining the target voltage reference value based on the voltage margin obtained through optimization and the initial voltage reference value includes: The target voltage reference value is determined by adding the initial voltage reference value and the voltage margin obtained through optimization.

6. The adaptive control method for motor bus voltage according to any one of claims 1 to 5, characterized in that, The voltage conversion circuit includes any one of a Buck converter, a Buck-Boost converter, and a Z-source inverter.

7. A motor bus voltage adaptive control device, characterized in that, A voltage conversion circuit is connected between the motor and the input power supply, and the voltage conversion circuit outputs a bus voltage to the motor. The device is used in the motor bus voltage adaptive control method according to any one of claims 1 to 6, and the device includes: The reference voltage initialization module is used to determine the initial voltage reference value based on the current operating state of the motor. The reference voltage optimization module is used to optimize the voltage margin used to compensate the initial voltage reference value, and to determine the target voltage reference value based on the optimized voltage margin and the initial voltage reference value. The voltage control loop module is used to determine the voltage tracking error based on the target voltage reference value and the bus voltage output by the voltage conversion circuit, and to determine the inductor current reference value of the voltage conversion circuit based on the voltage tracking error. The current control loop module is used to perform deadbeat current control on the voltage conversion circuit based on the inductor current reference value, the current inductor current of the voltage conversion circuit in the current motor control cycle, the bus voltage, and the input voltage of the input power supply, so that the bus voltage converges to the target voltage reference value.

8. A motor system, characterized in that, The system includes: Electric motor; Input power; Voltage conversion circuit; And the motor bus voltage adaptive control device as described in claim 7, wherein the input terminal of the voltage conversion circuit is connected to the input power supply, the output terminal of the voltage conversion circuit is connected to the motor, and the adaptive control device is connected to the control terminal of the voltage conversion circuit to adaptively control the bus voltage output by the voltage conversion circuit.

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