Permanent magnet motor driving method based on trajectory closed loop in driver and driver

Abstract

This invention provides a permanent magnet motor driving method and driver based on a closed-loop trajectory within the driver, belonging to the field of motor drive and control technology. The method includes: acquiring a virtual trajectory signal of the permanent magnet motor based on the current thrust command; acquiring a trajectory error signal of the permanent magnet motor based on the real-time position signal and the virtual trajectory signal; acquiring a fluctuation compensation thrust command for the permanent magnet motor based on the trajectory error signal; acquiring a drive thrust command for the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command; and adjusting the drive current of each phase of the permanent magnet motor according to the drive thrust command. This invention significantly improves the output linearity of the motor drive system by constructing a high-frequency trajectory closed loop within the driver to achieve closed-loop tracking and fluctuation compensation of the thrust command.

Description

Technical Field

[0001] This invention relates to the field of motor drive and control technology, and in particular to a permanent magnet motor drive method and driver based on a closed-loop trajectory within the driver. Background Technology

[0002] Permanent magnet motors, including permanent magnet synchronous rotary motors, linear motors, and planar motors, are widely used in various precision motion systems, such as lithography machine stages and precision machine tools, due to their high power density, high response speed, and high reliability. In these high-end applications, the system's motion accuracy requirements reach the nanometer or even sub-nanometer level, making the nonlinearity between the motor's thrust output and the thrust command particularly prominent. This nonlinearity mainly originates from the motor's cogging effect, end effect, magnetic field harmonics, and current control model errors, manifesting as the actual thrust output deviating from the ideal value and causing additional fluctuations in the motion trajectory, severely limiting the improvement of the system's ultimate accuracy.

[0003] In existing technologies, the main approaches to improving motor output nonlinearity include optimizing the motor body structure, such as using skewed pole and fractional slot designs, and improving motion control algorithms, such as using disturbance observers and iterative learning control. However, structural optimization is limited by manufacturing precision and cost, and cannot completely eliminate nonlinearity; while algorithm compensation based on motion controllers is limited by its finite servo frequency, usually on the order of 1kHz, making it difficult to effectively suppress high-frequency thrust fluctuations. Summary of the Invention

[0004] This invention provides a permanent magnet motor driving method and driver based on a closed-loop trajectory within the driver. By constructing a high-frequency trajectory closed loop inside the driver, closed-loop tracking and fluctuation compensation of thrust commands are achieved, thereby significantly improving the output linearity of the motor drive circuit.

[0005] In a first aspect, the present invention provides a permanent magnet motor driving method based on a closed-loop trajectory within the driver, comprising: The virtual trajectory signal of the permanent magnet motor is obtained according to the current thrust command of the permanent magnet motor; The trajectory error signal of the permanent magnet motor is obtained based on the real-time position signal of the permanent magnet motor and the virtual trajectory signal; The fluctuation compensation thrust command of the permanent magnet motor is obtained based on the trajectory error signal; The driving thrust command of the permanent magnet motor is obtained based on the current thrust command and the fluctuation compensation thrust command. The driving current of each phase of the permanent magnet motor is adjusted according to the driving thrust command.

[0006] In some embodiments, obtaining the virtual trajectory signal of the permanent magnet motor based on the current thrust command of the permanent magnet motor includes: The current thrust command is subjected to a second-order integral operation to obtain the virtual trajectory signal.

[0007] In some embodiments, the current thrust command is integrated second-order to obtain the virtual trajectory signal, satisfying the following formula: ; in, This indicates the current thrust command. Indicates speed signal, The virtual trajectory signal represents the value, and m represents the mover mass of the permanent magnet motor. In some embodiments, obtaining the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal includes: The trajectory error signal is input into the virtual trajectory controller, and the fluctuation compensation thrust command is obtained through the control calculation of the virtual trajectory controller.

[0008] In some embodiments, the virtual trajectory controller is a linear controller or a nonlinear controller.

[0009] In some embodiments, when the virtual trajectory controller is a linear controller, its control operations include at least one of proportional, integral, and derivative operations.

[0010] In some embodiments, obtaining the drive thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command includes: The fluctuation compensation thrust command is multiplied by a fusion coefficient related to the current thrust command and then superimposed with the current thrust command to obtain the driving thrust command.

[0011] Secondly, the present invention also provides a permanent magnet motor driver based on a closed-loop trajectory within the driver, comprising: The thrust trajectory unit is used to obtain the virtual trajectory signal of the permanent magnet motor according to the current thrust command of the permanent magnet motor. An error calculation unit is used to obtain the trajectory error signal of the permanent magnet motor based on the real-time position signal of the permanent magnet motor and the virtual trajectory signal; The trajectory control unit is used to obtain the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal; The compensation synthesis unit is used to obtain the driving thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command; A current drive unit is used to adjust the drive current of each phase of the permanent magnet motor according to the drive thrust command.

[0012] In some embodiments, the thrust trajectory unit is a second-order integrator, and the compensation synthesis unit is a proportional-integral-derivative controller.

[0013] Thirdly, the present invention also provides a permanent magnet motor motion control system, comprising: The host motion controller is used to issue the current thrust command; A position sensor is used to detect the position of the permanent magnet motor and generate a real-time position signal of the permanent magnet motor; The driver is communicatively connected to the permanent magnet motor, the host motion controller, and the position sensor, respectively, and is used to execute the permanent magnet motor driving method based on the closed loop of the driver's internal trajectory as described in the first aspect.

[0014] This invention is applicable to improving the output linearity of existing permanent magnet motors, such as permanent magnet synchronous rotary motors, linear motors, and planar motors, that is, the consistency between the thrust or torque output and the thrust command during motor driving. By constructing an additional virtual trajectory closed-loop structure in the driver, the closed-loop tracking of the motor thrust output to the thrust command is indirectly achieved, thereby compensating for thrust fluctuations and improving the linearity of the motor output. It can be applied to the improvement of the driving method of various permanent magnet motors, and solves the problem of motion accuracy deterioration caused by the non-ideal linearity of the motor drive link in precision and ultra-precision motion systems. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced one by one below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating a permanent magnet motor driving method based on closed-loop trajectory within the driver, provided by an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a permanent magnet motor driver based on a closed-loop trajectory within the driver, provided by an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a traditional permanent magnet motor driver; Figure 4 This is a structural diagram of the motor motion control system of the permanent magnet motor driver based on the closed loop of the driver's internal trajectory, provided in an embodiment of the present invention. Figure 5 This is a structural diagram of a motor motion control system using a traditional drive method; Figure 6The simulation results of thrust output under square wave thrust command are shown in the diagrams of the method of this invention and the traditional driving method. Figure 7 The figure shows the displacement error experimental results of the motor motion control system using the method of this invention and the traditional driving method under the fourth-order trajectory tracking test. 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 with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. 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] Permanent magnet motors generate motion by utilizing the interaction force between permanent magnets and energized coils. Common structural forms in engineering include permanent magnet synchronous rotary motors, linear motors, and planar motors. Because they use permanent magnets for excitation, permanent magnet motors have advantages such as simple structure, high power density, high positioning accuracy, high response speed, and high safety and reliability, and are widely used in various electromechanical motion systems.

[0019] In precision and ultra-precision motion systems using permanent magnet motors as drive components, such as in lithography machine workpiece stages, the adverse effects of motor output nonlinearity become increasingly apparent due to the extremely high requirements for system motion accuracy and dynamic performance. Motor output nonlinearity refers to the inconsistency between the motor's thrust or torque output and the thrust command, causing the thrust command and motor displacement to deviate from the ideal linear second-order integral relationship. This nonlinearity primarily stems from various undesirable factors present in actual motor operation, such as cogging effects, end effects, and magnetic field harmonics. This nonlinearity will cause fluctuations in motor displacement, making it difficult for the dynamic accuracy of the motion system to meet ultra-precision requirements.

[0020] To address the performance degradation of motion systems caused by motor output nonlinearity, existing improvement measures mainly fall into two categories: optimizing motor structural design and improving motion control methods. Optimizing motor structural design involves standardizing the actual electromagnetic field structure at the hardware level to match the ideal design as closely as possible. This primarily includes adjusting the shape and size of the magnetic poles and armature, such as using a skewed permanent magnet arrangement or a fractional-slot armature structure. Improving motion control methods involves designing error compensation mechanisms at the control algorithm level to eliminate the adverse effects of motor output nonlinearity. For example, a disturbance observer can be designed to treat thrust fluctuations as external disturbances and estimate them in real time, with corresponding compensation in the control input. Iterative learning control methods can be used to obtain the timing sequence of control inputs under optimal trajectory error, which can significantly suppress trajectory deviations caused by spatial repetitive components in thrust fluctuations.

[0021] While the above measures mitigate the nonlinearity of motor output or its negative impact on the motion system to some extent, corresponding limitations remain. Regarding optimizing motor structural design, on the one hand, it's impossible to avoid inaccurate nominal values ​​of structural parameters due to actual manufacturing and assembly errors; on the other hand, the assumption of an idealized sinusoidal distribution of the actual magnetic field in the drive current model remains unchanged, making it difficult to improve motor output linearity to its limit. As for improving motion control methods, the improvement is constrained by the performance limits of the control method. Even when using industry-recognized high-precision control methods, such as iterative learning control, which can compress repetitive disturbances to a limit level, its effectiveness in suppressing non-repetitive disturbances still relies on traditional feedback control.

[0022] In summary, improving the linearity of motor output has a significant effect on improving the dynamic performance of precision and ultra-precision motion systems. However, existing motor structure optimization methods and motion control methods all have their own limitations, making it difficult to meet the ever-increasing requirements of ultra-precision performance.

[0023] To address the aforementioned technical problems, this invention proposes a method for improving the output linearity of permanent magnet motors based on a closed-loop trajectory within the driver. This method is applicable to various permanent magnet motors, including permanent magnet synchronous rotary motors, linear motors, and planar motors, which require precise and ultra-precision motion control. By additionally setting a closed-loop trajectory structure within the driver, thrust closed-loop control is performed at a frequency much higher than that of the motion controller. This effectively compensates for thrust fluctuation errors caused by various undesirable factors, improves the motor's output linearity, and thus reduces the difficulty of precise motion control of the motor.

[0024] Figure 1 This is a schematic flowchart illustrating a permanent magnet motor driving method based on a closed-loop trajectory within the driver, provided in an embodiment of the present invention. The permanent magnet motor driving method based on a closed-loop trajectory within the driver can be executed by the permanent magnet motor driver based on a closed-loop trajectory within the driver provided in this embodiment of the invention. Figure 1 As shown, the permanent magnet motor drive method based on closed-loop trajectory within the driver includes the following steps: S101. Obtain the virtual trajectory signal of the permanent magnet motor based on the current thrust command of the permanent magnet motor.

[0025] Specifically, the current thrust command refers to the target value of thrust or torque that the permanent magnet motor is expected to output, calculated in real time by the host motion controller, such as a CNC system or motion control card, and sent to the driver. The virtual trajectory signal refers to the displacement that the motor should produce when executing the thrust command under ideal linear conditions, derived in reverse from the current thrust command; that is, the trajectory reference signal. The driver receives the current thrust command from the host controller and converts it into a desired displacement signal, i.e., the virtual trajectory signal, through theoretical calculation.

[0026] In some embodiments, obtaining the virtual trajectory signal of the permanent magnet motor based on the current thrust command of the permanent magnet motor includes: performing a second-order integral operation on the current thrust command to obtain the virtual trajectory signal.

[0027] Specifically, second-order integration refers to performing two consecutive integration operations on the input signal. The driver performs two consecutive integration operations on the received current thrust command. The first integration converts the current thrust command into theoretical velocity, and the second integration converts the theoretical velocity into theoretical displacement, thereby obtaining a virtual trajectory signal. Thus, this embodiment of the invention uses second-order integration to generate a virtual trajectory signal, which can accurately map the signal in the thrust command domain to the displacement command domain, laying the foundation for subsequent trajectory error calculation.

[0028] In some embodiments, a second-order integral operation is performed on the current thrust command to obtain a virtual trajectory signal, satisfying the following formula: ; in, Indicates the current thrust command. Indicates speed signal, This represents the virtual trajectory signal, and m represents the mass of the mover of the permanent magnet motor.

[0029] Specifically, the mover mass refers to the mass of the moving part in a permanent magnet motor, such as the rotor of a rotary motor or the mover of a linear motor. For rotary motors, this parameter corresponds to the equivalent moment of inertia, which can be set according to the actual load or obtained through identification methods. Therefore, this embodiment of the invention provides a clear and implementable calculation formula, and the introduction of the mover mass parameter makes the model more consistent with physical reality. By adjusting the mover mass, it can adapt to motors of different models or load conditions.

[0030] In some embodiments, during the operation of the permanent magnet motor, the mover mass of the permanent magnet motor can be identified and updated online using the recursive least squares method or the model reference adaptive algorithm.

[0031] Specifically, recursive least squares can continuously update the estimation of system parameters using new observation data. Model reference adaptive algorithms adjust controller parameters to make the output of the controlled system track the output of the ideal reference model, while simultaneously identifying system parameters online. The mover mass used by the driver during second-order integration can also be a variable value. During motor operation, the driver simultaneously runs an online parameter identifier, employing methods such as recursive least squares or model reference adaptive algorithms. The online parameter identifier dynamically estimates and updates the mover mass of the permanent magnet motor in the model using real-time acquired data such as the current thrust command and real-time position signal, and uses the updated value for second-order integration.

[0032] Therefore, this embodiment of the invention enables the dynamic model inside the driver to automatically adapt to changes in the real load through online identification, solving the problem that inaccurate model parameters lead to errors in the calculation of virtual trajectory signals, which in turn affect the compensation effect.

[0033] It should be noted that the mover mass primarily serves as a feedforward gain in the virtual trajectory closed loop. The accuracy of its value mainly affects the dynamic response of the closed-loop system, while having a negligible impact on the steady-state accuracy of the thrust and displacement outputs. This indicates that the method of this invention has a certain robustness to the model parameters. Furthermore, in some motion control architectures, the host motion controller directly issues acceleration commands. In this case, the driving method of this invention can directly set the mover mass to a unit mass, i.e., set it to 1, and treat the acceleration command as an equivalent thrust command, thus the method described in this invention is equally applicable.

[0034] S102. Obtain the trajectory error signal of the permanent magnet motor based on the real-time position signal and virtual trajectory signal of the permanent magnet motor.

[0035] Specifically, the real-time position signal refers to the actual position information of the permanent magnet motor's mover, detected and fed back in real time by position sensors such as linear encoders and encoders. The trajectory error signal refers to the difference between the virtual trajectory signal and the real-time position signal, which indirectly reflects the deviation between the actual thrust output and the current thrust command. The driver acquires the motor's real-time position signal and compares it with the virtual trajectory signal to obtain the trajectory error signal. The trajectory error signal essentially maps the deviation of the thrust output to the displacement domain.

[0036] In some embodiments, the trajectory error signal of the permanent magnet motor is obtained based on the real-time position signal and the virtual trajectory signal of the permanent magnet motor, satisfying the following formula: in, Indicates real-time location signal, Represents virtual trajectory signal, Trajectory error signal.

[0037] S103. Obtain the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal.

[0038] Specifically, the fluctuation compensation thrust command refers to the additional thrust command calculated based on the trajectory error signal to compensate for the fluctuation and nonlinear components present in the actual thrust output.

[0039] In some embodiments, obtaining the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal includes: inputting the trajectory error signal into a virtual trajectory controller, and obtaining the fluctuation compensation thrust command through the control calculation of the virtual trajectory controller.

[0040] Specifically, the virtual trajectory controller is a control module within the driver, used to calculate the required thrust compensation amount, i.e., the fluctuation compensation thrust command, based on the input trajectory error signal using a specific control algorithm. The control calculation can be linear or nonlinear. The core function of the virtual trajectory controller is to generate a compensation thrust based on the trajectory error signal, capable of driving the actual position to track the virtual trajectory command. Its design goal is to ensure that the internal virtual trajectory closed loop possesses good stability, fast response, and anti-interference capability. Therefore, by configuring the virtual trajectory controller, this embodiment of the invention can flexibly achieve effective correction of trajectory errors, thereby compensating for thrust fluctuations.

[0041] In some embodiments, the virtual trajectory controller is a linear controller or a nonlinear controller. When the virtual trajectory controller is a linear controller, its control operations include at least one of proportional, integral, and derivative operations.

[0042] Specifically, control operations can encompass various elementary or advanced mathematical operations, such as, but not limited to, proportions, integrals, derivatives, filtering, convolutions, and their combinations and function transformations. Their general form can be expressed as: ,in This represents the computational functions executed by the virtual trajectory controller.

[0043] In some embodiments, when the virtual trajectory controller is a linear controller, linear operations are performed on the trajectory error signal to obtain the fluctuation compensation thrust command, satisfying the following formula: ; in, This indicates a surge compensation thrust command. This indicates the trajectory error signal. , , The calculated coefficients refer to the gain parameters corresponding to the proportional, integral, and derivative terms in linear control operations.

[0044] Specifically, the linear operation can be a proportional-integral-differential operation. In the above formula, the proportional term is used to quickly respond to the current error, the integral term is used to eliminate the steady-state error, and the differential term is used to predict the error change trend and suppress overshoot. Therefore, this embodiment of the invention makes the generation of the compensation amount, i.e., the fluctuation compensation thrust command, have a clear mathematical basis and adjustability, through reasonable tuning. , , These three coefficients enable the internal trajectory closed loop to have good dynamic and static performance, thereby achieving effective and smooth compensation for thrust fluctuations.

[0045] In some embodiments, the fluctuation compensation thrust command can be obtained based on the trajectory error signal, or the trajectory error signal can be input into a nonlinear controller for processing; wherein, the gain of the nonlinear controller can be dynamically adjusted according to the magnitude or rate of change of the trajectory error signal.

[0046] Specifically, a nonlinear controller refers to a controller whose output and input do not satisfy a simple linear relationship, and whose gain may vary with the system state. Dynamic adjustment refers to the process by which the controller's parameters or internal rules change according to the real-time state of the system. A nonlinear controller receives trajectory error signals, but its internal processing rules or gain parameters are not fixed; instead, they are dynamically adjusted in real time according to the magnitude or rate of change of the current trajectory error signal. Therefore, when the error is large, a stronger control action can be used to quickly reduce the error; when the error is small, the gain can be reduced to avoid system chatter and improve steady-state accuracy. Through this dynamic adjustment, compared to a linear controller with fixed parameters, a nonlinear controller can achieve better dynamic performance and stronger anti-interference capabilities over a wider operating range, potentially resulting in better fluctuation compensation.

[0047] For example, dynamic adjustment may include: when the absolute value of the trajectory error signal is less than a first set threshold, using a first control gain; when the absolute value of the trajectory error signal is greater than or equal to the first set threshold and less than a second set threshold, using a second control gain less than the first control gain; and when the absolute value of the trajectory error signal is greater than or equal to the second set threshold, limiting the amplitude of the output fluctuation compensation thrust command.

[0048] Specifically, the first and second preset thresholds are two pre-defined threshold values ​​used to divide the error range, with the second threshold being greater than the first. Control gain, the coefficient multiplied by the proportional and integral terms in the controller, directly affects the strength of the control action. Amplitude limiting forcibly restricts the amplitude of the controller's output signal, ensuring it does not exceed a preset maximum allowable value. When the absolute value of the trajectory error signal is less than the first preset threshold, the controller uses a larger first control gain to achieve high-precision control. When the absolute value of the error is between the first and second thresholds, a smaller second control gain is used to prevent excessive control. When the absolute value of the error exceeds the second threshold, it indicates that the system may be subject to a large disturbance or an anomaly. In this case, the controller no longer follows the conventional control law but directly limits its output fluctuation compensation thrust command to a safe maximum amplitude. Therefore, it ensures control accuracy under small errors while preventing controller output saturation under large errors or disturbances, avoiding excessive impact on the system or causing instability.

[0049] In some embodiments, after obtaining the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal, the method further includes: performing time-frequency domain analysis on the fluctuation compensation thrust command; identifying periodic components in the fluctuation compensation thrust command that are in sync with the motor's mechanical cycle or non-periodic abrupt change components that exceed a preset range based on the time-domain analysis results; and generating a fault warning signal when periodic components or non-periodic abrupt change components are identified.

[0050] Specifically, time-frequency domain analysis refers to mathematical methods that simultaneously extract and analyze features of a signal in both the time and frequency dimensions, such as short-time Fourier transform and wavelet transform. Periodic components refer to frequency components in a signal that appear synchronously with the mechanical motion cycle of a motor. Non-periodic abrupt change components refer to transient or impulsive components in a signal that appear suddenly and whose amplitude deviates significantly from the normal fluctuation range.

[0051] The actuator performs time-frequency domain analysis on the fluctuation compensation thrust command. In the frequency domain, spectral lines with abnormally increased amplitudes and frequencies in sync with the motor's mechanical cycle can be identified, potentially indicating periodic mechanical faults such as bearing wear or mover imbalance. In the time domain, abrupt spikes exceeding a preset safety threshold can be detected, possibly corresponding to non-periodic abnormal events such as instantaneous guide rail jamming or sudden load collisions. Once these abnormal components are identified, the actuator generates and reports a fault warning signal. Therefore, this embodiment of the invention eliminates the need for additional vibration or force sensors; utilizing only the existing signal and processing capabilities within the actuator, it achieves early fault diagnosis and health management of critical mechanical components, improving the system's intelligence and maintainability, preventing problems before they occur, and avoiding downtime or damage due to escalating faults.

[0052] S104. Obtain the driving thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command.

[0053] Specifically, the drive thrust command refers to the total thrust command ultimately used to control the motor current, obtained by combining the current thrust command and the fluctuation compensation thrust command. For example, the drive thrust command for the permanent magnet motor is obtained based on the current thrust command and the fluctuation compensation thrust command, satisfying the following calculation formula: in, Indicates the current thrust command. This indicates a surge compensation thrust command. This indicates the driving thrust command for the permanent magnet motor.

[0054] In some embodiments, obtaining the driving thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command also includes: multiplying the fluctuation compensation thrust command by a fusion coefficient related to the current thrust command and then superimposing it with the current thrust command to obtain the driving thrust command.

[0055] Specifically, the fusion coefficient refers to a variable weighting coefficient associated with the current thrust command, used to adjust the contribution of the fluctuation compensation thrust command in the final synthesis. The synthesis of the driving thrust command is not simply an addition of the current thrust command and the fluctuation compensation thrust command, but rather the introduction of a fusion coefficient. The specific synthesis formula is as follows: Among them, the fusion coefficient This is the current thrust command. The function. For example, when When the speed is very low, the motor may be operating at low speed or near zero speed. At this speed, thrust fluctuations have a relatively large impact, but sensor noise may also be amplified. Therefore, a smaller fusion coefficient can be set. To reduce the amount of compensation that may be affected by noise pollution; when When the value is large, the fusion coefficient can be set. Approaching 1, the compensation effect is fully utilized. Therefore, this embodiment of the invention, by introducing a fusion coefficient related to the main command, achieves intelligent modulation of the compensation effect, avoiding the risk that the compensation loop might introduce additional noise or cause unnecessary responses under specific operating conditions, such as low thrust commands, further optimizing the overall performance of the system across the entire operating range.

[0056] S105. Adjust the driving current of each phase of the permanent magnet motor according to the driving thrust command.

[0057] Specifically, the driver distributes and adjusts the drive current of each phase coil of the permanent magnet motor according to the drive thrust command, thereby driving the motor to move. For example, based on the drive thrust command and combined with the current position of the motor and the thrust constant DQ (Direct-Quadrature) decomposition model, the required current for each phase coil, such as i, can be calculated. A i B i C The system outputs precise current through power devices to achieve the target thrust output. It should be noted that the specific algorithm for determining the drive current of each phase of the permanent magnet motor based on the drive thrust command is well known to those skilled in the art and will not be elaborated here.

[0058] In summary, this invention additionally constructs a trajectory closed-loop structure within the driver, namely, a trajectory feedback equivalent closed-loop control path structure. This indirectly achieves closed-loop tracking of the motor thrust output to the thrust command received by the driver, resulting in a high degree of linearity in the motor drive process. The trajectory closed-loop structure construction can include additionally setting up a thrust-trajectory second-order integrator within the driver. The current thrust command received by the driver from the upper-level motion controller in the motor servo system is processed by the second-order integrator to obtain a virtual trajectory signal. The trajectory error signal is obtained by subtracting the real-time position signal fed back by the motor from this virtual trajectory signal. A virtual trajectory controller is set up within the driver, and the trajectory error signal is input to this virtual trajectory controller to obtain a fluctuation-compensated thrust command. After superimposing the fluctuation-compensated thrust command with the current thrust command issued by the upper-level controller, it is connected to the current loop. The motor's current position and thrust constant model are used to allocate the current of each phase coil to drive the motor, achieving precise drive and improving the linearity of the thrust output. This is suitable for servo systems requiring precise thrust control, such as permanent magnet synchronous rotary motors and linear motors.

[0059] Therefore, this invention essentially constructs a virtual trajectory loop nested within the driver, making the thrust command indirectly a reference input for trajectory control. Thrust output is adjusted through trajectory error feedback, thereby achieving closed-loop tracking of the thrust command. Without modifying the upper-level motion controller structure, the consistency between thrust output and command can be significantly improved, enhancing the linearity of the input-output characteristics of the motor drive, making it particularly suitable for applications with high requirements for thrust disturbance suppression and dynamic accuracy. Compared to existing thrust fluctuation compensation methods that improve motion control, this invention, by performing thrust closed-loop control within a driver with higher dynamic computing performance, possesses a servo frequency five to ten times higher than that of the motion controller. Therefore, it can effectively compensate for high-frequency thrust ripple that is difficult to eliminate with motion control methods, resulting in more accurate thrust output and displacement control results.

[0060] This invention also provides a permanent magnet motor driver based on a closed-loop trajectory within the driver. Figure 2 This is a schematic diagram of a permanent magnet motor driver based on a closed-loop trajectory within the driver, provided by an embodiment of the present invention. Figure 2As shown, the permanent magnet motor driver based on a closed-loop trajectory within the driver includes a thrust trajectory unit 201, an error calculation unit 202, a trajectory control unit 203, a compensation synthesis unit 204, and a current drive unit 205. The thrust trajectory unit 201 is used to obtain the virtual trajectory signal of the permanent magnet motor based on the current thrust command of the permanent magnet motor; the error calculation unit 202 is used to obtain the trajectory error signal of the permanent magnet motor based on the real-time position signal and the virtual trajectory signal of the permanent magnet motor; the trajectory control unit 203 is used to obtain the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal; the compensation synthesis unit 204 is used to obtain the driving thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command; the current drive unit, i.e., the current loop 205, is used to adjust the driving current of each phase of the permanent magnet motor according to the driving thrust command. Therefore, the permanent magnet motor driver based on a closed-loop trajectory within the driver has the beneficial effects described in the above embodiments, which will not be repeated here.

[0061] In some embodiments, the thrust trajectory unit 201 is a second-order integrator, and the compensation synthesis unit 203 is a proportional-integral-derivative controller.

[0062] Specifically, a second-order integrator refers to an electronic circuit or digital signal processing algorithm module capable of performing two consecutive integral operations on an input signal. A proportional-integral-derivative (PID) controller refers to an electronic circuit or digital signal processing algorithm module capable of implementing a PID (Proportional-Integral-Derivative) control algorithm. The thrust trajectory unit 201 consists of a second-order integrator hardware or a fixed algorithm, used to perform second-order integral operations on the current thrust command to obtain a virtual trajectory signal. The trajectory control unit 203 consists of a proportional-integral-derivative (PID) controller, used to perform PID operations on the trajectory error signal to obtain a fluctuation compensation thrust command.

[0063] Figure 3 This is a schematic diagram of a traditional permanent magnet motor driver. In contrast, the structure of a traditional motor drive method that does not use the method of this invention is as follows: Figure 3 As shown, after receiving the current thrust command from the upper controller, the driver directly inputs it into the current loop, and distributes the current of each phase coil according to the DQ decomposition to drive the motor. Since there is no displacement feedback thrust closed-loop control channel, it is impossible to compensate for actual motor thrust disturbances and DQ decomposition model errors in real time. Therefore, the motor drive circuit will have significant nonlinearity, posing difficulties for precision motion control.

[0064] Figure 4 This is a structural diagram of the motor motion control system of the permanent magnet motor driver based on the closed loop of the driver's internal trajectory, provided in an embodiment of the present invention. Figure 5 This is a structural diagram of a motor motion control system using a traditional drive method. (Comparison) Figure 4The method of the present invention shown is used with Figure 5 The structure of the motor motion control system using the traditional motor drive method is shown. It can be seen that the method of the present invention opens up a new displacement feedback closed-loop control channel in the motion control system. This channel has a higher response bandwidth than the position loop where the motion controller is located, which can effectively compensate for the nominal thrust deviation and tune the controlled object acted by the motion controller into an ideal linear second-order integral system, which greatly reduces the difficulty of precision motion control.

[0065] Figure 6 The figure shows the simulation results of thrust output under square wave thrust command using the method of this invention and the traditional driving method. Figure 7 The figure shows the displacement error experimental results of the motor motion control system using the method of this invention and the traditional driving method under the fourth-order trajectory tracking test. Figure 6 The horizontal axis represents time in seconds, and the vertical axis represents thrust in kilometres (N). Curve b represents the input ideal square wave thrust command, and curve c represents the corresponding... Figure 2 The thrust output under the structure shown is represented by curve d. Figure 3 The thrust output under the structure shown. Figure 6 As can be seen, after using the method of the present invention, the fluctuation error of the output thrust is significantly reduced, and the root mean square error of the thrust output is 0.015N, which is 95.5% lower than the 0.33N of the traditional driving method. Figure 7 The horizontal axis represents time in seconds (s), and the vertical axis represents displacement error in nanometers (nm). Curve 'e' represents a scaled reference acceleration curve corresponding to the fourth-order motion trajectory, used to visually demonstrate the relationship between displacement error and motion state, especially during acceleration and deceleration. Curve 'f' represents the corresponding... Figure 4 The displacement error under the structure shown is represented by curve g. Figure 5 The displacement error under the structure shown. (From...) Figure 7 It can be seen that after using the method of the present invention, the displacement error of trajectory tracking is significantly reduced, with a root mean square error of 16.77 nm, which is 84.9% lower than the 111.2 nm of the traditional driving method.

[0066] This invention also provides a permanent magnet motor motion control system, including a host motion controller, a position sensor, and a driver. The host motion controller is used to issue a current thrust command; the position sensor is used to detect the position of the permanent magnet motor and generate a real-time position signal of the permanent magnet motor; the driver is communicatively connected to the permanent magnet motor, the host motion controller, and the position sensor, and is used to execute the permanent magnet motor driving method based on the closed loop of the driver's internal trajectory as described in the above embodiments. Therefore, it has the beneficial effects described in the above embodiments, which will not be repeated here.

[0067] Specifically, the upper-level motion controller refers to the controller located above the actuator, responsible for overall motion planning, trajectory generation, and high-level control. Position sensors are devices used to detect the actual position of the moving parts of the permanent magnet motor. Communication connection refers to the electrical or wireless connection used to transmit commands, data, and signals. The upper-level motion controller is responsible for calculating and issuing the current thrust command. The position sensor detects the motor position in real time and generates a real-time position signal. The actuator, as the core execution component, receives the thrust command and position signal, executes the method described in the above embodiments, and ultimately outputs drive current to the permanent magnet motor, forming a complete control closed loop. The upper-level controller focuses on macroscopic motion planning and the external closed loop, while delegating the high-bandwidth thrust linearization compensation task to the internal closed loop of the actuator. This architecture fully leverages the performance advantages of each hardware component, enabling the entire system to achieve a significant improvement in thrust output linearity and motion accuracy without excessively relying on the computing power of the upper-level controller.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A permanent magnet motor driving method based on closed-loop trajectory within the driver, characterized in that, include: The virtual trajectory signal of the permanent magnet motor is obtained according to the current thrust command of the permanent magnet motor; The trajectory error signal of the permanent magnet motor is obtained based on the real-time position signal of the permanent magnet motor and the virtual trajectory signal; The fluctuation compensation thrust command of the permanent magnet motor is obtained based on the trajectory error signal; The driving thrust command of the permanent magnet motor is obtained based on the current thrust command and the fluctuation compensation thrust command. The driving current of each phase of the permanent magnet motor is adjusted according to the driving thrust command.

2. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to claim 1, characterized in that, Obtaining the virtual trajectory signal of the permanent magnet motor based on the current thrust command of the permanent magnet motor includes: The current thrust command is subjected to a second-order integral operation to obtain the virtual trajectory signal.

3. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to claim 2, characterized in that, The virtual trajectory signal is obtained by performing a second-order integral operation on the current thrust command, satisfying the following formula: ； in, This indicates the current thrust command. Indicates speed signal, The virtual trajectory signal is represented by m, which represents the mass of the mover of the permanent magnet motor.

4. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to claim 1, characterized in that, Obtaining the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal includes: The trajectory error signal is input into the virtual trajectory controller, and the fluctuation compensation thrust command is obtained through the control calculation of the virtual trajectory controller.

5. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to claim 4, characterized in that, The virtual trajectory controller is a linear controller or a nonlinear controller.

6. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to claim 5, characterized in that, When the virtual trajectory controller is a linear controller, its control operations include at least one of proportional, integral, and derivative operations.

7. The permanent magnet motor driving method based on closed-loop trajectory within the driver according to any one of claims 1-6, characterized in that, The drive thrust command of the permanent magnet motor is obtained based on the current thrust command and the fluctuation compensation thrust command, including: The fluctuation compensation thrust command is multiplied by a fusion coefficient related to the current thrust command and then superimposed with the current thrust command to obtain the driving thrust command.

8. A permanent magnet motor driver based on a closed-loop trajectory within the driver, characterized in that, include: The thrust trajectory unit is used to obtain the virtual trajectory signal of the permanent magnet motor according to the current thrust command of the permanent magnet motor. An error calculation unit is used to obtain the trajectory error signal of the permanent magnet motor based on the real-time position signal of the permanent magnet motor and the virtual trajectory signal; The trajectory control unit is used to obtain the fluctuation compensation thrust command of the permanent magnet motor based on the trajectory error signal; The compensation synthesis unit is used to obtain the driving thrust command of the permanent magnet motor based on the current thrust command and the fluctuation compensation thrust command; A current drive unit is used to adjust the drive current of each phase of the permanent magnet motor according to the drive thrust command.

9. The permanent magnet motor driver based on closed-loop trajectory within the driver according to claim 8, characterized in that, The thrust trajectory unit is a second-order integrator, and the compensation synthesis unit is a proportional-integral-derivative controller.

10. A motion control system for a permanent magnet motor, characterized in that, include: The host motion controller is used to issue the current thrust command; A position sensor is used to detect the position of the permanent magnet motor and generate a real-time position signal of the permanent magnet motor; The driver is communicatively connected to the permanent magnet motor, the host motion controller, and the position sensor, respectively, and is used to execute the permanent magnet motor driving method based on the closed loop of the driver's internal trajectory as described in any one of claims 1-7.

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