Memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance

Abstract

The application discloses a memory motor current feedback time-sharing filter control method considering dynamic and steady state performance, which divides memory motor current control into two time periods, namely, a steady state operation period and a dynamic field regulation period. In the steady state operation period, the direct and quadrature axis currents are subjected to low-pass filtering to eliminate high-frequency noise, and then are fed back to the current controller to weaken current ripple in the steady state operation period and reduce motor operation noise. In the dynamic field regulation period, the low-pass filter at the direct and quadrature axis current feedback position is cancelled to eliminate the phase delay caused by the low-pass filter, thereby accelerating the current response speed, ensuring that the direct axis field regulation current can be accurately tracked, and reducing the current fluctuation caused by the cross-coupling effect, so as to weaken the field regulation torque fluctuation. The memory motor current control method can not only make the memory motor have smaller operation noise in the steady state operation period, but also make the memory motor have accurate current tracking performance and smaller field regulation torque fluctuation in the dynamic field regulation period.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of motor control, and particularly relates to a memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance. BACKGROUND

[0002] With the continuous development of science and technology, a variable flux permanent magnet synchronous motor (VFPMSM), also known as a memory motor, uses the characteristic that the magnetization state of a low coercive force permanent magnet is easy to change, and changes the magnetization state of the low coercive force permanent magnet by applying a current pulse, so as to change the permanent magnet flux linkage of the motor. The memory motor of the alternating current magnetic modulation type needs to inject a current pulse in the direct axis to realize magnetic modulation, and the amplitude of the current pulse is as high as 3-4 times the rated current. Due to the cross-coupling effect, the quadrature axis current also produces a large fluctuation.

[0003] In order to solve the problem, a current controller with decoupling function is generally selected. At present, some scholars use a feedforward PI current controller and a feedforward active disturbance rejection controller to realize the decoupling between the direct-axis current and the quadrature-axis current, so as to ensure accurate tracking of the direct-axis current and the quadrature-axis current. However, only selecting the current controller with the decoupling function cannot guarantee that the memory motor has excellent current control performance in both steady state operation and dynamic magnetic modulation.

[0004] In view of the above problems, the present application provides a memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance, which guarantees that the memory motor has excellent current control performance in both steady state operation and dynamic magnetic modulation, and reduces operating noise and magnetic modulation torque.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance comprises the following steps:

[0008] S1, determining whether magnetic modulation is needed according to the running state of the memory motor, and dividing the running of the memory motor into two different periods: when magnetic modulation is not needed, the flag PMflag=0, and a control method of the direct-axis current given i d * = 0 or a maximum torque current ratio control method is adopted; when magnetic modulation is needed, the flag PMflag=1, the direct-axis current is given a magnetic modulation pulse according to the target flux linkage, and the quadrature-axis current is given the output of a speed controller with constant speed as the target;

[0009] S2, judging whether to add or remove the low-pass filter feedback by the current controller according to whether the field current pulse is applied in the direct axis, when the field current pulse is not applied in the direct axis, i.e. steady state operation, the quadrature and direct axis currents are fed back to the current controller through the low-pass filter, i.e. d * = i dlpf , i q * = i qlpf , i dlpf is the filtered quadrature axis current, i qlpf is the filtered direct axis current; when the field current pulse is applied in the direct axis, i.e. dynamic field regulation, the quadrature and direct axis currents are directly fed back to the current controller;

[0010] S3, according to the state of the given current and the feedback current, the current controller outputs the quadrature and direct axis voltages, and then outputs the three-phase voltage through the voltage vector control to control the motor to operate stably.

[0011] Further, the current controller is not limited to the feedforward PI controller, and different current controllers all adopt the current feedback filtering control method.

[0012] Further, in S2, when the motor operates stably, the current feedback through the low-pass filter can effectively eliminate high-frequency noise, so as to weaken the current ripple in the steady state operation and reduce the motor operating noise; when the motor operates dynamically, the low-pass filter at the current feedback position is cancelled, so as to eliminate the phase delay caused by the low-pass filter, thereby accelerating the current response speed, ensuring that the direct axis field current can be accurately tracked, and reducing the current fluctuation caused by the cross-coupling effect, so as to weaken the field regulation torque fluctuation.

[0013] Advantages of the application:

[0014] 1. The memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance can reduce the memory motor operating noise, because the quadrature and direct axis currents have small fluctuations when the memory motor operates stably.

[0015] 2. The memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance can ensure that the direct axis current can be accurately tracked and accurately regulate the field, because the current response is fast when the memory motor operates dynamically.

[0016] 3. The memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance can reduce the electromagnetic torque fluctuation in the memory motor field regulation process, thereby reducing the speed fluctuation, because the quadrature axis current has small fluctuations when the memory motor operates dynamically. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0018] Figure 1 is a memory motor current feedback time-sharing filter control block diagram considering dynamic and steady state performance of the present application;

[0019] Figure 2 is a memory motor running state schematic diagram when the feedforward PI current controller uses a low-pass filter;

[0020] Figure 3 is a memory motor running state schematic diagram when the feedforward PI current controller does not use a low-pass filter;

[0021] Figure 4 is a memory motor running state schematic diagram when the feedforward PI current controller uses the method of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the protection scope of the present application.

[0023] As shown in Figure 1 , the memory motor current feedback time-sharing filter control method considering dynamic and steady state performance adopts a feedforward PI current controller, and includes the following steps:

[0024] S1, judging whether it is necessary to adjust the magnetism according to the memory motor running state, and dividing the memory motor running into two different time periods, i.e. when it is not necessary to adjust the magnetism, the flag PMflag=0, and adopting the control method of the direct axis current given i d * = 0 or the maximum torque current ratio control method; when it is necessary to adjust the magnetism, the flag PMflag=1, and adjusting the magnetism according to the target flux linkage given direct axis current pulse, and at the same time, the quadrature axis current given is the output of the speed controller with constant speed as the target;

[0025] Embodiment 1

[0026] When the motor speed rises to 950 rpm, the demagnetizing current pulse is applied to the direct axis of the motor, the demagnetizing current amplitude is -25 A, the permanent magnet flux linkage after demagnetization is 0.145 Wb, and the direct axis current given during demagnetization can be expressed as:

[0027]

[0028] When the motor speed drops to 700 rpm, a magnetizing current pulse is applied to the direct axis of the motor, the magnetizing current amplitude is 30 A, and the permanent magnet flux after magnetizing is 0.245 Wb. The direct axis current given during magnetizing can be expressed as:

[0029]

[0030] S2, whether to add or remove the low-pass filter feedback by the current controller is judged according to whether a magnetizing current pulse is applied to the direct axis. When no magnetizing current pulse is applied to the direct axis, i.e. steady-state operation, the direct and quadrature axis currents are fed back to the current controller through the low-pass filter, i.e. d *=i dlpf , i q *=i qlpf , where i dlpf is the filtered quadrature axis current, and i qlpf is the filtered direct axis current; when a magnetizing current pulse is applied to the direct axis, i.e. dynamic magnetizing, the direct and quadrature axis currents are directly fed back to the current controller.

[0031] During steady-state operation, the current feedback through the low-pass filter can effectively eliminate high-frequency noise, thereby weakening the current ripple during steady-state operation and reducing the motor operating noise. During dynamic magnetizing, the low-pass filter at the direct and quadrature axis current feedback is removed to eliminate the phase delay caused by the low-pass filter, thereby speeding up the current response and ensuring that the direct axis magnetizing current can accurately track. At the same time, the current fluctuation caused by the cross-coupling effect is reduced to weaken the magnetizing torque fluctuation.

[0032] S3, according to the state of the given current and the feedback current, the current controller outputs the direct and quadrature axis voltages, and then outputs the three-phase voltage through voltage vector control to control the stable operation of the motor.

[0033] Figure 2 、 Figure 3 、 Figure 4 The memory motor operating states when the feedforward PI current controller uses the low-pass filter, when the feedforward PI current controller does not use the low-pass filter, and when the feedforward PI current controller uses the method of the present application are respectively shown, including motor speed change curves, torque change curves, direct axis current change curves and quadrature axis current change curves.

[0034] In order to verify the advantages of the present application, three groups of comparative experiments were conducted. The memory motor operating state when the feedforward PI current controller uses the low-pass filter is shown in FIG. 1, the memory motor operating state when the feedforward PI current controller does not use the low-pass filter is shown in FIG. 2, and the memory motor operating state when the feedforward PI current controller uses the method of the present application is shown in FIG. 3. Figure 2As shown in the experimental results, although the memory motor has small current fluctuation in the steady state, the cross-axis current fluctuation is large when the memory motor is magnetized and demagnetized, which results in large torque fluctuation and speed fluctuation. Figure 3 For the memory motor running state when the feedforward PI current controller does not use the low-pass filter, compared with Figure 2 , the cross-axis current fluctuation is significantly reduced when the memory motor is magnetized and demagnetized, but the cross-axis current fluctuation is large in the steady state, which produces large running noise. The memory motor running state when the feedforward PI current controller uses the method of the present application is shown in Figure 4 The method of the present application combines the advantages of the above two methods, so that the memory motor has small current fluctuation and low noise in the steady state, and the torque and speed fluctuation are also significantly reduced when the memory motor is magnetized and demagnetized.

[0035] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0036] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A memory motor current feedback time-sharing filtering control method considering dynamic and steady state performance, characterized in that, Comprising the following steps: S1, according to the memory motor operating state to determine whether to need to adjust the magnetic, memory motor operation is divided into two different periods - no need to adjust the magnetic flag PMflag = 0, using the direct axis current given The control method or the maximum torque current ratio control method; need to adjust the magnetic flag PMfla = 1, according to the target flux given direct axis current magnetic pulse, at the same time, the output of the cross axis current given is the constant speed controller for the target speed controller; S2, judging whether to add or remove the low-pass filter feedback by the current controller according to whether to apply the field current pulse in the direct axis - when the direct axis is not applied with the field current pulse, i.e. in the steady state operation, the cross and direct axis currents after filtering by the low-pass filter are fed back to the current controller after operation with the given cross and direct axis current values; when the direct axis is applied with the field current pulse, i.e. in the dynamic field regulation, the cross and direct axis currents are fed back to the current controller after operation with the given cross and direct axis current values; S3, outputting the cross and direct axis voltages by the current controller according to the states of the given and feedback currents, and then outputting the three-phase voltages by the voltage vector control to control the motor to operate stably.

2. The memory motor current feedback split-time filtering control method with consideration of dynamic and steady state performance according to claim 1, characterized in that, The current controller is a feedforward PI controller.

3. The memory motor current feedback split-time filtering control method with consideration of dynamic and steady state performance according to claim 1, characterized in that, In the S2, in the steady state operation, the current feedback through the low-pass filter can effectively eliminate the high-frequency noise to weaken the current ripple in the steady state operation and reduce the motor operation noise; in the dynamic field regulation, the low-pass filter at the current feedback is cancelled to eliminate the phase delay caused by the low-pass filter, thereby accelerating the current response speed, ensuring the direct axis field current to be accurately tracked, and reducing the current fluctuation caused by the cross-coupling effect to weaken the field regulation torque fluctuation.

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