A Current Loop Control Method for a Permanent Magnet Synchronous Motor in Three-Phase Asymmetrical State

Abstract

This invention provides a current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical conditions, comprising: constructing a three-phase asymmetrical model of the permanent magnet synchronous motor with resistive and inductive asymmetry, and extending the three-phase asymmetrical model to a two-phase rotating coordinate system; employing a deadbeat current control algorithm under three-phase asymmetry, incorporating asymmetrical resistance and inductance parameters into the deadbeat current control, and calculating the voltage and current at the current moment based on the initial voltage and current in the two-phase rotating coordinate system. This invention establishes a complete three-phase asymmetrical state model, analyzes the impact of resistance and inductance asymmetry on the system, and improves the current loop control effect by optimizing the current loop control algorithm.

Description

Technical Field

[0001] This invention relates to the field of servo control, and more specifically, to a current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical conditions. Background Technology

[0002] Permanent magnet synchronous motors have advantages such as high efficiency, high power density, and good dynamic performance. However, during motor use, damage to the stator insulation and manufacturing defects can alter the symmetry of the three phases of the stator, causing torque pulsation and speed fluctuations.

[0003] Existing research on the three-phase asymmetry characteristics of PMSMs includes online identification of three-phase asymmetry resistance values ​​for fault diagnosis, but only discusses the impact of resistance asymmetry on the system. Alternatively, research on modeling and simulation of stator inter-turn short-circuit faults in PMSMs analyzes PMSM models for resolving stator inter-turn short-circuit faults, but only considers stator inter-turn short-circuit faults. Summary of the Invention

[0004] To address the problem of poor dynamic response of the current loop in a three-phase unbalanced state of a permanent magnet synchronous motor (PMSM), this invention provides a current loop control method for a PMSM under three-phase unbalanced state, comprising:

[0005] A three-phase asymmetric model of the resistance and inductance asymmetry of a permanent magnet synchronous motor is constructed, and the three-phase asymmetric model is extended to a two-phase rotating coordinate system.

[0006] A deadbeat current control algorithm under three-phase asymmetry is adopted, which introduces the asymmetric resistance parameters and asymmetric inductance parameters into the deadbeat current control. Based on the initial voltage and current in a two-phase rotating coordinate system, the voltage and current at the current moment are calculated.

[0007] This invention provides a current loop control method for a permanent magnet synchronous motor (PMSM) under three-phase asymmetrical conditions. It establishes a complete three-phase asymmetrical state model, analyzes the impact of resistance and inductance asymmetry on the system, and optimizes the current loop control algorithm to reduce the static current error of the PMSM during operation, thereby improving the accuracy and robustness of the current loop control and enhancing the current loop control effect. Attached Figure Description

[0008] Figure 1 The present invention provides a flowchart of a current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical conditions. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined with each other to form feasible technical solutions. Such combinations are not constrained by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0010] To address the issue of poor dynamic response of the current loop under three-phase asymmetrical conditions in PMSM, Figure 1 A flowchart of a current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical conditions provided by the present invention is shown below. Figure 1 As shown, the method includes:

[0011] Step 1: Construct a three-phase asymmetric model of the permanent magnet synchronous motor with resistance asymmetry and inductance asymmetry, and extend the three-phase asymmetric model to a two-phase rotating coordinate system.

[0012] The three-phase asymmetric model of the permanent magnet synchronous motor in the d / q rotating coordinate system is as follows:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] in, To introduce the asymmetric resistance parameter, R dq R qd R is the coupling resistor. dd R qq For d-axis and q-axis resistance; To introduce the asymmetric inductance parameter, L dq L qd For the coupled inductor, L dd L qq For d-axis and q-axis inductance; i d iq For d-axis and q-axis currents; u d u q ω represents the voltages along the d and q axes; e ω is the electric angular velocity of the rotor. f The flux linkage between the permanent magnet and the stator is p; the differential operator is R. a R b R c R is the three-phase stator resistance. a R b R c Not equal; L aa L bb and L cc M represents the self-inductance coefficient of the three-phase stator windings; ab M ac M ba M bc M ca and M cb This represents the mutual inductance coefficient of the three-phase stator windings; It is a rotation matrix.

[0019] It is understandable that in the three-phase asymmetric model of a permanent magnet synchronous motor in the d / q rotating coordinate system... The resistance parameter introduced is R in the traditional motor model. dd R dq R qd and R qq All are equal, meaning that symmetrical resistance parameters are introduced into the motor model. However, in the motor model of this invention, R... dd R dq R qd and R qq Unequal, meaning the introduction of asymmetrical resistance parameters. Similarly, For the introduced inductance parameter, L in the traditional motor model dd L dq L qd and L qq All are equal, meaning that symmetrical inductance parameters are introduced into the motor model, while L in this invention... dd L dq L qd and L qq This means that asymmetrical inductance parameters are introduced into the motor model, which is more consistent with the actual operation model of the motor.

[0020] Step 2: The deadbeat current control algorithm under three-phase asymmetry is adopted. The asymmetric resistance parameters and asymmetric inductance parameters are introduced into the deadbeat current control. Based on the initial voltage and current in the two-phase rotating coordinate system, the voltage and current at the current moment are calculated.

[0021] Understandably, the asymmetrical resistance and inductance parameters are introduced into the three-phase asymmetrical model of the permanent magnet synchronous motor, and a deadbeat current control algorithm is introduced into the model to calculate the two-phase rotating voltage and two-phase rotating current at any time in real time.

[0022] Specifically, based on the three-phase asymmetric permanent magnet synchronous motor model, the forward Euler method is used for discretization, resulting in the following discrete motor model:

[0023]

[0024] The discrete motor model after considering delay compensation is as follows:

[0025]

[0026] in,

[0027]

[0028]

[0029]

[0030] Among them, i d (k), i q (k) represents the d-axis and q-axis currents at time k; i d * (k), i q * (k) represents the d-axis and q-axis currents at time k; u d (k), u q (k) represents the d-axis and q-axis voltages at time k; ω e (k) represents the electric angular velocity of the rotor at time k; T s This refers to the operating cycle of a permanent magnet synchronous motor.

[0031] From the discrete motor model after time delay compensation, it can be seen that the two-phase rotating voltage and two-phase rotating current at time k+1 are related to the two-phase rotating voltage and two-phase rotating current at time k (i.e., the previous time). Therefore, it is necessary to calculate the two-phase rotating voltage and two-phase rotating current at time k+1, which is actually a cyclic iterative process. During the cyclic iterative process, it is necessary to obtain the two-phase rotating voltage and two-phase rotating current at the initial time.

[0032] Therefore, the initial voltage u in the two-phase rotating coordinate system at the start of the permanent magnet synchronous motor is obtained. d (0), u q (0) and initial current i d (0), i q (0); based on the initial voltage u d(0), u q (0) and initial current i d (0), i q (0), Based on the discrete motor model considering delay compensation, the voltage u at the current moment is calculated by a cyclic iterative method. d (k+1) and current u q (k+1) is used to control the two-phase rotating voltage and two-phase rotating current of the permanent magnet synchronous motor.

[0033] This invention provides a current loop control method for a permanent magnet synchronous motor (PMSM) under three-phase asymmetrical conditions. It establishes a complete three-phase asymmetrical state model, analyzes the impact of resistance and inductance asymmetry on the system, and optimizes the current loop control algorithm to reduce the static current error of the PMSM during operation, thereby improving the accuracy and robustness of the current loop control and enhancing the current loop control effect.

[0034] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0035] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0036] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0037] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0038] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0039] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0040] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical conditions, characterized in that, include: A three-phase asymmetric model of the resistance and inductance asymmetry of a permanent magnet synchronous motor is constructed, and the three-phase asymmetric model is extended to a two-phase rotating coordinate system. A deadbeat current control algorithm under three-phase asymmetry is adopted, which introduces the asymmetric resistance parameters and asymmetric inductance parameters into the deadbeat current control. Based on the initial voltage and current in the two-phase rotating coordinate system, the voltage and current at the current moment are calculated. The three-phase asymmetric model extended to a two-phase rotating coordinate system is as follows: ； ； ； ； ； in, The introduced asymmetric resistance parameters, , For coupling resistors, , For d-axis and q-axis resistance; To introduce asymmetric inductance parameters, , For coupled inductors, , For d-axis and q-axis inductance; , These are the d-axis and q-axis currents; , These are the d-axis and q-axis voltages; The electric angular velocity of the rotor; The magnetic flux linkage between the permanent magnet and the stator; It is a differential operator; , , For three-phase stator resistance, , , They are not equal; , and Indicates the self-inductance coefficient of the three-phase stator windings; , , , , and Indicates the mutual inductance coefficient of the three-phase stator windings; , It is a rotation matrix.

2. The current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical state according to claim 1, characterized in that, Based on the aforementioned three-phase asymmetric model, the discrete motor model can be obtained by discretizing it using the forward Euler method: ； The discrete motor model after considering delay compensation is as follows: ； in, ; ， ， ， ； ； ； in, , Let d and q be the currents at time k; , Let k be the given current along the d and q axes at time k; , Let d and q be the voltages at time k; Let T be the electric angular velocity of the rotor at time k. s This refers to the operating cycle of a permanent magnet synchronous motor.

3. The current loop control method for a permanent magnet synchronous motor under three-phase asymmetrical state according to claim 2, characterized in that, The calculation of the voltage and current at the current moment based on the initial voltage and current in a two-phase rotating coordinate system includes: Obtain the initial voltage in the two-phase rotating coordinate system when the permanent magnet synchronous motor starts. , and initial current , ; Based on the initial voltage , and initial current , The voltage at the current moment is calculated based on the discrete motor model considering delay compensation. and current .

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