Permanent magnet synchronous motor driving control method, recording medium and system

Abstract

The invention belongs to the technical field of motor control, and particularly relates to a permanent magnet synchronous motor driving control method, a traversal optimization process is removed through an angle search method, and the increase of the number of virtual voltage vectors does not increase the calculated amount of a system. Therefore, compared with a traditional model prediction control method, the number of the virtual voltage vectors constructed in the proposed method can be selected at will, the control effect is not limited by the hardware computing power any more, the over-modulation problem is optimized under the condition that no additional control module is added, and the control effect is improved. And the control and dynamic response performance of the permanent magnet synchronous motor is improved. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

Description

Technical Field

[0001] The invention belongs to the technical field of motor control and discloses a permanent magnet synchronous motor drive control method, a recording medium and a system. Background Art

[0002] With the continuous improvement of permanent magnet material performance, the improvement of processing technology and the rapid development of modern control technology, permanent magnet synchronous motors have shown strong competitiveness in many fields, including transportation, wind power generation, industrial production, household appliances, medical equipment, aerospace and military industry. The core of permanent magnet synchronous motors lies in their drive control system, which plays a key role in ensuring the safe and stable operation of permanent magnet synchronous motors in various working environments. The drive control system usually consists of a converter, a controller, a power supply and a sensor, among which the controller generates control instructions for the converter through a control algorithm, thereby achieving precise control of the motor. The control algorithm directly determines the operating performance of the motor.

[0003] The traditional permanent magnet synchronous motor control algorithm uses a proportional-integral module to track the command speed and command current, but this method requires manual adjustment of the proportional and integral parameters, and for different models of motors, re-debugging is required. In addition, the proportional-integral method has a relatively weak response capability to sudden changes in commands, which may cause the motor to fluctuate significantly when the command changes suddenly. In contrast, the model predictive control-based method generates control commands by predicting the motor state of the next cycle without the need for initial parameter adjustment. Since the control commands are generated based on real-time measurement data, model predictive control has excellent dynamic response capabilities.

[0004] In the model predictive control method, all potential voltage vectors need to be traversed to find the best solution, and the more voltage vectors there are, the better the control performance. However, as the number of candidate voltage vectors increases, the computational complexity of the system will also increase. Therefore, the number of candidate voltages in model predictive control is limited by the computing power of the processor. When the number of candidate voltage vectors is insufficient, the error between the control instruction and the actual action per cycle is large, and the current harmonics of the motor will increase significantly during operation. In addition, when the load or speed instruction changes suddenly, the motor may enter a transient overload state. At this time, the inverter enters an overmodulation state and cannot accurately execute the voltage vector instruction, resulting in the occurrence of control errors and a decrease in control performance. Summary of the invention

[0005] In view of the above problems, the present invention provides a permanent magnet synchronous motor drive control method, comprising the following steps:

[0006] S1. According to the synthetic relationship of the command voltage vector, the unit calculation is realized through coordinate system transformation;

[0007] S2. Determine the sector where the voltage vector is located by the coordinate value of the command voltage vector in the transformed coordinate system, and calculate the command voltage vector angle according to the sector and the coordinate value;

[0008] S3. Construct a set of virtual voltage vectors, and search for a virtual voltage vector closest to the angle of the command voltage vector as the optimal voltage vector according to the angle of the command voltage vector and the sector in which it is located;

[0009] S4. The duty cycle of the cycle is solved by the command voltage vector and the optimal voltage vector; the on-time of the three-phase switch of the inverter in one cycle is calculated by the duty cycle;

[0010] S5. The three-phase switches of the inverter are closed-loop controlled by the opening time to complete the drive control of the permanent magnet synchronous motor.

[0011] Preferably, in step S2, the command voltage vector located in the overmodulation region is corrected, and the angle of the command voltage vector is adjusted so that the corrected voltage vector is located in the modulatable region.

[0012] Preferably, the coordinate system transformation in step S1 includes transforming the command voltage vector from the dq rotating coordinate system to the αβ fixed coordinate system, and then transforming the command voltage vector from the αβ fixed coordinate system to the gh basic voltage vector coordinate system through coordinate transformation.

[0013] Another solution of the present invention is to provide a non-transitory readable recording medium for storing one or more programs including a plurality of instructions. When the instructions are executed, the processing circuit will execute the above-mentioned permanent magnet synchronous motor drive control method.

[0014] Another embodiment of the present invention is to provide a permanent magnet synchronous motor drive control system, including a processing circuit and a memory electrically coupled thereto, wherein the memory is configured to store at least one program, wherein the program includes multiple instructions, and the processing circuit runs the program to execute the above-mentioned permanent magnet synchronous motor drive control method.

[0015] Compared with the prior art, the permanent magnet synchronous motor drive control method, recording medium and system provided by the present invention have the following beneficial effects:

[0016] The traversal optimization process is eliminated by the angle search method, and the increase in the number of virtual voltage vectors will not increase the amount of calculation of the system. Therefore, compared with the traditional model predictive control method, the number of virtual voltage vectors constructed in the proposed method can be arbitrarily selected, the control effect is no longer limited by the hardware computing power, and the control performance of the permanent magnet synchronous motor is greatly improved.

[0017] On this basis, an overmodulation processing scheme based on the proposed angle search method is proposed to address the overmodulation problem that may exist in the inverter during motor operation. The overmodulation problem is optimized without adding additional control modules, thereby improving the dynamic response performance of the motor control system when the load or speed command changes suddenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the process of a permanent magnet synchronous motor drive control method in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making innovative efforts are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, an embodiment of a permanent magnet synchronous motor drive control device provided by the present invention is as follows:

[0021] The first step is to transform and normalize the command voltage vector.

[0022] In the actual process of permanent magnet synchronous motor, after calculating the synthetic relationship of the command voltage vector, the command voltage vector is transformed from the dq rotating coordinate system to the αβ fixed coordinate system:

[0023]

[0024] Where θ is the motor rotation angle, and is the coordinate of the command voltage vector in the αβ fixed coordinate system, and is the coordinate of the command voltage vector in the dq rotating coordinate system.

[0025] The voltage vector is transformed from the αβ fixed coordinate system to the gh basic voltage vector coordinate system through coordinate transformation, so as to realize the normalized calculation. The transformation process is as follows:

[0026]

[0027] Among them, u g and u h is the coordinate of the command voltage vector in the gh coordinate system.

[0028] The parameters in the above coordinate transformation process are as follows:

[0029]

[0030]

[0031] Among them, u dc is the DC bus voltage.

[0032] The second step is to use the command voltage vector coordinate value u g and u h Determine the sector where the command voltage vector is located:

[0033] Set two parameters x and y.

[0034] When u g ≥0 and u h ≥0, it is determined that the command voltage vector is located in the first voltage sector, at this time x=u g ,y=u h .

[0035] When u g <0 and u h ≥0 and u g +u h ≥0, it is determined that the command voltage vector is located in the second voltage sector, at this time x=u h +u g ,y=-u g .

[0036] When u g <0 and u h ≥0 and u g +u h When x is less than 0, it is determined that the command voltage vector is located in the third voltage sector. At this time, x = u h ,y=-u g -u h .

[0037] When u g <0 and u h When x is less than 0, it is determined that the command voltage vector is located in the fourth voltage sector, and at this time x = -u g ,y=-u h .

[0038] When u g ≥0 and u h <0 and u g +u h When x is less than 0, it is determined that the command voltage vector is located in the fifth voltage sector, and at this time x = -u g -u h ,y=u h .

[0039] When u g≥0 and u h <0 and u g +u h ≥0, it is determined that the command voltage vector is located in the sixth voltage sector, at this time x=-u h ,y=u g +u h .

[0040] After obtaining the parameters x and y, the command voltage vector angle is calculated as follows:

[0041]

[0042] Wherein, γ is the angle of the command voltage vector in the gh coordinate system.

[0043] The third step is to correct the command voltage vector in the overmodulation area and adjust the voltage command vector angle so that the corrected voltage vector is in the modulatable area.

[0044] When x+y>=1 or |xy|<=1, the x and y values ​​are corrected as follows:

[0045]

[0046] Substitute the corrected x and y values ​​back into the calculation to obtain the corrected voltage vector angle γ.

[0047] When xy>1, the voltage vector angle γ is directly corrected as follows:

[0049] γ=0°

[0050] When xy<-1, the voltage vector angle γ is directly corrected as follows:

[0052] γ=60°

[0053] Step 4: Solve for the optimal voltage vector

[0054] Construct a virtual voltage vector set, and obtain the number of the optimal voltage vector in the virtual voltage vector set according to the obtained command voltage vector angle γ

[0055] n b =round[γ / (60 / N)]

[0056] Among them, round is an approximate rounding function used to round the result of γ / N, N is the number of sectors, n b The voltage vector number whose angle is closest to the command voltage vector angle.

[0057] The optimal voltage vector after restoration is obtained through the following transformation:

[0058] ub =(1-n b *f)*u a +n b *f*u a+1

[0059] Where, f = 1 / N, a is the sector number where the selected optimal voltage vector is located, ranging from 1 to 6, and u b is the optimal voltage vector selected, u a and u a+1 are the basic voltage vectors numbered a and a+1 respectively. When the optimal voltage vector is in sector VI, u a and u a+1 u 6 and u 1 .

[0060] The basic voltage vector in the above equation can be expressed as

[0061]

[0062] in

[0063]

[0064]

[0065] Step 5: Obtain the three-phase switching time index per cycle

[0066] The duty cycle of the cycle is solved by the command voltage vector and the optimal voltage vector.

[0067]

[0068] The on-time of the three-phase switch in one cycle is obtained by calculating the duty cycle.

[0069]

[0070] Among them, T 1 , T 2 , T 3 The on-time of the three-phase switch in one cycle.

[0071] When the optimal voltage vector is in sector II, T 2 , T 1 , T 3 They are the on-time of the A-phase, B-phase and C-phase switches in one cycle.

[0072] When the optimal voltage vector is in sector III, T 3 , T 1 , T 2 They are the on-time of the A-phase, B-phase and C-phase switches in one cycle.

[0073] When the optimal voltage vector is in sector IV, T 3 , T 2 , T 1 They are the on-time of the A-phase, B-phase and C-phase switches in one cycle.

[0074] When the optimal voltage vector is in sector V, T 2 , T 3 , T 1 They are the on-time of the A-phase, B-phase and C-phase switches in one cycle.

[0075] When the optimal voltage vector is in sector VI, T 1 , T 3 , T 2 They are the on-time of the A-phase, B-phase and C-phase switches in one cycle.

[0076] The three-phase switch of the inverter is controlled by the calculated three-phase switch opening time, thereby completing the control of the permanent magnet synchronous motor in this cycle.

[0077] Compiling the above method steps into a program and then storing it on a hard disk or other non-transitory storage medium constitutes an embodiment of "a non-transitory readable recording medium" of the present invention; and electrically connecting the storage medium to a computer processor and completing the drive control of the permanent magnet synchronous motor through data processing constitutes an embodiment of "a permanent magnet synchronous motor drive control system" of the present invention.

[0078] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computers, available storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0079] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0082] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A permanent magnet synchronous motor drive control method, characterized in that: The following steps are involved: S1. According to the synthetic relationship of the command voltage vector, the unit calculation is realized through coordinate system transformation; S2. Determine the sector where the voltage vector is located by the coordinate value of the command voltage vector in the transformed coordinate system, and calculate the command voltage vector angle according to the sector and the coordinate value; S3. Construct a set of virtual voltage vectors, and search for a virtual voltage vector closest to the angle of the command voltage vector as the optimal voltage vector according to the angle of the command voltage vector and the sector in which it is located; S4. The duty cycle of the cycle is solved by the command voltage vector and the optimal voltage vector; the on-time of the three-phase switch of the inverter in one cycle is calculated by the duty cycle; S5. The three-phase switches of the inverter are closed-loop controlled by the opening time to complete the drive control of the permanent magnet synchronous motor.

2. A permanent magnet synchronous motor drive control method according to claim 1, characterized in that: In step S2, the command voltage vector located in the overmodulation area is corrected, and the command voltage vector angle is adjusted so that the corrected voltage vector is located in the modulatable area.

3. A permanent magnet synchronous motor drive control method according to claim 2, characterized in that: The coordinate system transformation in step S1 includes transforming the command voltage vector from dq The rotating coordinate system is transformed into the αβ fixed coordinate system, and then transformed from the αβ fixed coordinate system to the gh basic voltage vector coordinate system through coordinate transformation.

4. A non-transitory readable recording medium for storing one or more programs including a plurality of instructions, characterized in that: When the instruction is executed, the processing circuit will be caused to execute a permanent magnet synchronous motor drive control method as described in any one of claims 1-3.

5. A permanent magnet synchronous motor drive control system, comprising a processing circuit and a memory electrically coupled thereto, characterized in that: The memory configuration stores at least one program, the program includes a plurality of instructions, and the processing circuit runs the program to execute a permanent magnet synchronous motor drive control method as described in any one of claims 1-3.

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