Motor vector control device and motor driving system
By monitoring and controlling the motor operating parameters in real time, the synchronous cascade PID output in the inductive FOC control system is achieved, solving the asynchronous output of the output limit value, and improving the stability and efficiency of motor control.
Patent Information
- Application Number
- CN202311871292.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
In inductive FOC control systems, the output limits of existing cascade PID controllers cannot be synchronized, resulting in the stability and efficiency of motor control being affected.
By monitoring the operating parameters of the motor in real time, the main control chip is used to adjust the input request of the pre-level PID to ensure that the pre-level PID output does not continue to increase when the post-level PID output reaches the limit, and synchronize the pre-level PID output.
It improves the dynamic response performance and stability of the motor drive system, avoids system failures, and improves control efficiency.
Smart Images
Figure CN120237999A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of motor control. More specifically, the present invention relates to a motor vector control device and a motor drive system including the motor vector control device. Background Art
[0002] Motor vector control (also known as sensorless field-oriented control, abbreviated as sensorless FOC) technology is an advanced motor control strategy that realizes independent control of the motor magnetic field and torque by decomposing the stator current of the motor into two orthogonal components. This control method is based on the coordinate transformation theory, which transforms the motor control problem into a synchronous rotating coordinate system, making the motor control more intuitive and simple.
[0003] For example, in the vector control system of a permanent magnet synchronous motor, a double closed-loop control strategy is generally adopted. The speed controller and the current controller are used as the outer loop and the inner loop respectively. Both of these control loops can use traditional PID controllers, so it is also called a cascade PID control strategy. The advantage of this cascade control strategy is that the principle is simple and the robustness is strong, and it can effectively control the motor under different working conditions.
[0004] However, in the actual application process of this cascade control strategy, the output limits of the two loops cannot be synchronized with each other, and there may be a situation where the inner loop (current PID) has a response delay, which is not conducive to realizing the stability of motor control and the efficient operation of the motor. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to achieve synchronization of the cascade PID output limits in a sensorless FOC control system. By real-time controlling the input request of the front-stage PID, it is ensured that when the output of the rear-stage PID reaches the output limit, the output of the front-stage PID will not continue to increase, thereby avoiding invalid requests of the rear-stage PID, and further achieving the effect of cascade PID output synchronization.
[0006] Specifically, a first aspect of the present invention proposes a motor vector control device, which includes a speed detection module, a parameter acquisition module, a first conversion module, and a main control chip. The speed detection module is configured to detect the actual value ω of the current speed of the motor in real time during the operation of the motor. The parameter acquisition module is configured to acquire at least one operating parameter of the motor in real time during the operation of the motor. The first conversion module is configured to determine the actual value I of the current current of the motor based on the at least one operating parameter provided by the parameter acquisition module q , and the main control chip is configured to determine and output the speed request value ω of the motor according to the user request REF , and the device further includes:
[0007] A first controller stage, wherein the first controller stage is configured to receive the actual speed value ω from the speed detection module and receive the motor speed request value ω from the main control chip REF , and based on the actual speed value ω and the speed request value ω REF The deviation Δω between them is used to adjust the current request value I output to the second controller stage QREF ;and
[0008] A second controller stage is configured to receive the current actual value I from the first conversion module. q and receiving the current request value I from the first controller stage QREF , and based on the actual current value I q With the current request value I QREF The deviation ΔI between them is used to adjust the voltage control value V used to control the motor operation. q ,
[0009] The main control chip is further configured to monitor in real time the voltage control value V output by the second controller stage. q Whether it exceeds the preset maximum voltage limit V limit , and at the voltage control value V q exceeds the maximum voltage limit V limit The speed request value ω output to the first controller stage is adjusted REF .
[0010] According to an optional embodiment, the main control chip is further configured to: q exceeds the maximum voltage limit V limit , automatically switches to the limit mode, in which the speed request value ω provided to the first controller stage REF It is always equal to the actual value of the motor's current speed ω.
[0011] According to an optional embodiment, the main control chip is further configured to continuously monitor the voltage control value V output by the second controller stage in the limit mode. q , wherein, when the voltage control value V q drops to the maximum voltage limit V limit When the value is below 0.05, the limit mode of the main control chip is released.
[0012] According to an optional embodiment, the at least one operating parameter includes the current three-phase current of the motor, and the current actual value I q Including the q-axis current obtained by converting the three-phase current.
[0013] According to an optional embodiment, the voltage control value Vq is the q-axis voltage of the motor, and the device further includes a second conversion module configured to convert the q-axis voltage into three-phase voltages for controlling a three-phase inverter bridge of the motor.
[0014] According to an optional embodiment, the first conversion module includes a Clark converter and a Park converter, and / or the second conversion module includes an inverse Park converter and an inverse Clark converter.
[0015] According to an optional embodiment, the first controller stage and the second controller stage respectively include a PID controller.
[0016] According to an optional embodiment, the main control chip is formed as a part of the motor controller.
[0017] A second aspect of the present invention also proposes a motor drive system, which includes:
[0018] a motor; and
[0019] the motor vector control device as described above.
[0020] According to an optional embodiment, the motor is a permanent magnet synchronous motor.
[0021] The motor vector control device according to the present invention can effectively solve the output synchronization problem of the existing cascade PID controller in motor control applications, thereby improving the dynamic response performance and stability of the entire motor drive system. In particular, the device can monitor and control the input requests of the front and rear stage PID controllers in real time, thereby avoiding system failures caused by asynchronous output limits and improving the reliability of the system. In addition, the device can synchronize the output limits of the front and rear stage PIDs in a timely manner, avoiding the ineffective increase of the output of the front stage PID and improving the control efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] By incorporating the drawings herein and the following specific embodiments used to illustrate certain principles of the present invention, other features and advantages of the method of the present invention will become clear or will be more specifically illustrated. Figure 1 shows a schematic structural diagram of a conventional cascade PID control strategy.
[0023] Figure 1 shows a schematic diagram of the output responses of the front and rear stage controllers in the cascade PID control strategy.
[0024] Figure 2 shows Figure 1 the
[0025] Figure 3The structural schematic diagram of a motor vector control device according to an exemplary embodiment of the present invention is shown.
[0026] Figure 4 It shows a Figure 3 flowchart of a cascade controller output limit synchronization method implemented based on the vector control device in Detailed implementation manners
[0027] The motor vector control device according to the present invention will be described below with reference to the accompanying drawings and through embodiments. In the following description, many specific details are set forth in order to enable those skilled in the art to more fully understand the present invention. However, it is obvious to those skilled in the art that some of these specific details may not be required for the implementation of the present invention. On the contrary, the present invention can be implemented by considering any combination of the following features and elements, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims.
[0028] The cascade PID controller is a widely used motor vector control (also known as sensorless FOC) strategy, which includes two or more PID controllers connected together in a certain order. In this structure, the output of the front-stage PID serves as the set value of the rear-stage PID. This structure can improve the control accuracy and stability of the system. However, in some cases, if the output limits of the cascade PID are not synchronized, it may lead to a lag in the speed control response. This is because when the rear-stage PID reaches its output limit, if the front-stage PID continues to increase its output, the rear-stage PID will not be able to effectively respond to the request of the front-stage PID, resulting in a decrease in the response speed of the entire system.
[0029] Figure 1 The structural schematic diagram of a conventional cascade PID control strategy is shown. In this Figure 1 one, the speed PID and the current PID serve as the front-stage and rear-stage controllers respectively. The outputs of these two controllers both have their respective maximum limits (the maximum current limit and the maximum voltage limit respectively) in the application. However, in some cases, the output of the rear-stage current PID reaches the limit first, which causes the output of the front-stage speed PID to no longer be able to play its role, thus affecting the control performance of the entire system.
[0030] Figure 2 It shows a Figure 1 schematic diagram of the output responses of the front-stage and rear-stage controllers in the cascade PID control strategy of Figure 2As shown, when the output of the secondary current PID reaches the maximum limit value, further increasing the output of the primary speed PID will have no effect. When the speed demand value decreases, it is necessary to first reduce the output value of the speed PID (i.e., the current request value), and then affect the reduction of the output value of the current PID, which will cause a response delay of the current PID.
[0031] To solve this problem, the present invention proposes a new motor vector control device. This device adopts the method of synchronously cascading the PID output limit value, and ensures that when the output of the secondary PID reaches the limit value, the output of the primary PID will not continue to increase by real-time monitoring and controlling the input requests of the front and rear stage PID controllers. This can avoid invalid requests of the secondary PID, realize the synchronization of the front and rear cascaded PID outputs, and thus improve the response speed and performance of the motor control system.
[0032] Figure 3 FIG. shows a schematic structural diagram of a motor vector control device according to an exemplary embodiment of the present invention. As Figure 1 shown, the device includes a speed detection module S1, a parameter acquisition module (not shown in the figure), a first conversion module D1, and a main control chip (not shown in the figure). Among them, the speed detection module S1 is used to detect the actual speed value ω of the motor M in real time during the operation of the motor M, and the parameter acquisition module is used to acquire at least one operating parameter of the motor in real time during the operation of the motor, for example, the three-phase current i a , i b , i c . In this article, the motor M can especially be a permanent magnet synchronous motor.
[0033] The first conversion module D1 can determine the actual current value I of the motor M based on at least one operating parameter provided by the parameter acquisition module q , and this actual current value I q can be, for example, the q-axis current converted from the collected three-phase currents i a , i b , i c . The main control chip can be a part of the motor controller, and it can determine and output the speed request value ω of the motor M according to the user request REF .
[0034] As Figure 1 shown, the device adopts a cascaded PID control strategy to control the operation of the motor. Specifically, the device includes first and second controller levels C1, C2, and each of these two controller levels includes a corresponding PID controller PI1, PI2. In this example, the first controller level C1 is the outer loop, which is also called the "speed PID", and the second controller level C2 is the inner loop, which is also called the "current PID".
[0035] Functionally, the first controller stage C1 is responsible for receiving the actual rotational speed value ω from the rotational speed detection module S1 and the rotational speed request value ω of the motor M from the main control chip (not shown). REF . Based on the deviation Δω between the actual rotational speed value ω and the rotational speed request value ω REF , the first controller stage C1 can adjust the current request value I output to the second controller stage C2 QREF .
[0036] The second controller stage C2 is responsible for receiving the actual current value I from the first conversion module D1 q and the current request value I from the first controller stage C1 QREF . Based on the deviation ΔI between the actual current value I q and the current request value I QREF , the second controller stage C2 can further adjust the voltage control value V for controlling the operation of the motor q . The voltage control value V output by the second controller stage C2 q is especially the q-axis voltage of the motor M. In order to convert this q-axis voltage into the three-phase voltages V a , V b , V c that can control the three-phase inverter bridge H of the motor M, the device may further include a second conversion module D2, and the second conversion module D2 may specifically include an inverse Park converter and an inverse Clark converter (also called an "SVM pulse width modulator").
[0037] The special feature of this embodiment of the present invention is that during the control process of the motor, the main control chip can also monitor in real time whether the voltage control value V output by the second controller stage C2 (i.e., the current PID) exceeds a preset maximum voltage limit value V q , and when the voltage control value V limit exceeds the maximum voltage limit value V q , adjust the rotational speed request value ω output to the first controller stage C1 limit . REF .
[0038] Figure 4 shows a flowchart of a cascade controller output limit synchronization method implemented based on the vector control device in Figure 3 . Specifically, referring to Figure 4 , first, a limit mode trigger condition can be preset inside the main control chip. This condition can be, for example, that the output of the inner loop controller (i.e., the current PID) - that is, the voltage control value V q - exceeds the maximum voltage limit value V limit .
[0039] When this condition is reached, it means that further increase in the output of the outer loop controller (i.e., speed PID) will not cause any reaction from the inner loop controller. To avoid such ineffective increase, the main control chip can automatically switch to the limit mode. In this limit mode, the speed request value ω provided to the first controller stage C1 (by the main control chip) REF is always equal to the actual speed value ω of the current motor M. Since the speed request value remains unchanged, the output of the speed PID will not continue to increase.
[0040] As an optional example, in this limit mode, the main control chip can continuously monitor the voltage control value V output by the second controller stage C2 q , where when it is monitored that the voltage control value V q drops below the maximum voltage limit V limit , the limit mode of the main control chip can be automatically lifted, thus restoring the normal double closed-loop control strategy of the motor; conversely, the limit mode is continued, that is, V q is always equal to V limit .
[0041] An exemplary embodiment of the present invention also proposes a motor drive system, which includes a motor M and the motor vector control device described above.
[0042] The motor vector control device according to the present invention can effectively solve the output synchronization problem of the existing cascade PID controller in motor control applications, thereby improving the dynamic response performance and stability of the entire motor drive system. In particular, this device can monitor and control the input requests of the front and rear stage PID controllers in real time, thus avoiding system failures caused by asynchronous output limits and improving the reliability of the system. In addition, this device can synchronize the output limits of the front and rear stage PIDs in a timely manner, avoiding ineffective increase in the output of the front stage PID and improving the control efficiency of the system.
[0043] Those skilled in the art can understand that the various steps of the method according to the present invention are not limited to being implemented in the order listed above. In addition, in the present invention, terms such as "comprising" and "including" mean that in addition to having the steps directly and clearly stated in the specification and claims, the technical solutions of this application do not exclude the situation of having other steps not directly or clearly stated.
[0044] Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should be incorporated into the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.
Claims
1. A motor vector control device, which includes a speed detection module (S1), a parameter acquisition module, a first conversion module (D1) and a main control chip. The speed detection module (S1) is configured to detect the actual current speed ω of the motor (M) in real time during the operation of the motor (M). The parameter acquisition module is configured to acquire at least one operating parameter of the motor in real time during the operation of the motor. The first conversion module (D1) is configured to determine the actual current value I of the motor (M) based on the at least one operating parameter provided by the parameter acquisition module q , and the main control chip is configured to determine and output the requested speed value ω of the motor (M) according to a user request REF , characterized in that The device further includes: The first controller stage (C1), the first controller stage (C1) is configured to receive the actual rotational speed value ω from the rotational speed detection module (S1) and the rotational speed request value ω of the motor (M) from the main control chip REF , and based on the deviation Δω between the actual rotational speed value ω and the rotational speed request value ω REF to adjust the current request value I output to the second controller stage (C2) QREF ; and Second controller stage (C2), the second controller stage (C2) being configured to receive the actual current value I from the first conversion module (D1) q and to receive the requested current value I from the first controller stage (C1) QREF , and based on the actual current value I q and the requested current value I QREF to adjust the voltage control value V for controlling the operation of the motor based on the deviation ΔI q , Wherein, the main control chip is further configured to monitor in real time whether the voltage control value V output by the second controller stage (C2) exceeds a preset maximum voltage limit value V q , and when the voltage control value V limit exceeds the maximum voltage limit value V q , adjust the rotational speed request value ω output to the first controller stage (C1) limit . REF .
2. The motor vector control device according to claim 1, wherein The main control chip is further configured to automatically switch to the limit mode when the voltage control value V q exceeds the maximum voltage limit V limit , and in this limit mode, the rotational speed request value ω REF provided to the first controller stage (C1) is always equal to the actual rotational speed value ω of the current motor (M).
3. The motor vector control device according to claim 2, characterized in that The main control chip is further configured to continuously monitor the voltage control value V output by the second controller stage (C2) in the limit mode q , where when it is monitored that the voltage control value V q drops below the maximum voltage limit V limit , the limit mode of the main control chip is released.
4. The motor vector control device according to any one of claims 1 to 3, characterized in that The at least one operating parameter includes the current three-phase current of the electric machine (M), and the actual current value I q includes a q-axis current obtained by converting the three-phase current.
5. The motor vector control device according to any one of claims 1 to 3, characterized in that The voltage control value V q is the q-axis voltage of the motor (M), and the device further includes a second conversion module (D2), which is configured to convert the q-axis voltage into three-phase voltages for controlling the three-phase inverter bridge (H) of the motor (M).
6. The motor vector control device according to claim 5, characterized in that The first conversion module (D1) includes a Clark converter and a Park converter; and / or, the second conversion module (D2) includes an inverse Park converter and an inverse Clark converter.
7. The motor vector control device according to any one of claims 1 to 3, characterized in that, The first controller stage (C1) and the second controller stage (C2) respectively include PID controllers (PI1, PI2).
8. The motor vector control device according to any one of claims 1 to 3, characterized in that The main control chip is formed as part of a motor controller.
9. A motor drive system, characterized in that, The system includes: a motor (M); and a motor vector control device according to any one of claims 1 to 8.
10. The motor drive system according to claim 9, characterized in that, The motor (M) is a permanent magnet synchronous motor.