Two-degree-of-freedom control method for discrete domain current loop of permanent magnet synchronous motor

Abstract

The invention relates to the field of permanent magnet synchronous motor control, in particular to a two-degree-of-freedom control method for a discrete domain current loop of a permanent magnet synchronous motor. According to the method, a current controller is designed through a coefficient matrix F and an input matrix G of a discrete domain mathematical model of the permanent magnet synchronousmotor under a rotating dq coordinate system, and the problem of angle lag caused by compensation digital control one-beat delay is considered. According to the invention, the following rapidity design of the current loop of the permanent magnet synchronous motor is not restricted by the anti-interference performance. The introduction of the additional parameter freedom degree can realize the active configuration of the anti-interference performance, and meanwhile, the contradiction between the current tracking rapidity and the parameter robustness of the permanent magnet synchronous motor isbetter overcome, the parameter robustness of the system is improved to a greater extent while the rapid or minimum beat current response is obtained, and the operation quality of the current control system of the permanent magnet synchronous motor is further improved.

Description

technical field [0001] The invention relates to the field of permanent magnet synchronous motor control, in particular to a two-degree-of-freedom control method for a discrete domain current loop of a permanent magnet synchronous motor. Background technique [0002] Permanent magnet synchronous motors are widely used in high-performance drive applications such as new energy vehicles and industrial servo systems due to their high efficiency, high power density, specific power, and high starting torque. For many years, the proportional-integral (PI) controller based on the rotor field-oriented synchronous rotating coordinate system has been the industry standard for AC motor current control because of its wide speed range and zero steady-state error. However, the current commonly used current controllers will have the following problems when facing the high-speed and low-carrier ratio operation state: 1) The cross-coupling disturbance term introduced by the rotation coordinate...

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Problems solved by technology

However, the current commonly used current controllers will have the following problems when facing the high-speed and low-carrier ratio operation state: 1) The cross-coupling disturbance term introduced by the rotation coordinate transformation between the d and q-axis subsystems increases with the increase of the operating speed However, the increase in height even becomes the main determinant factor of the d and q axis current components, which brings great disturbance to the control performance of the d and q axis subsystems; 2) limited by the allowable switching frequency and heat dissipation conditions of power devices, the corresponding The carrier ratio is low, which makes the discretization error prominent, the influence of sampling and control delay is aggravated, and even leads to system instability in severe cases

[0008] 1. The uneven air gap of the built-in permanent magnet synchronous motor makes the AC and direct axis inductance unequal, and the complex vector technology cannot be used to simplify the permanent magnet motor voltage model into a single-input single-output model. Based on the single-input and single-output control object described by the vector, the discrete domain design scheme of the current controller is not suitable for the built-in permanent magnet synchronous motor;

[0009] 2. The design of the discrete domain current controller for the built-in permanent magnet synchronous motor reported in reference 3 has the problem that the current loop following performance and the anti-disturbance performance cannot be taken into account at the same time, and the parameter deviation seriously restricts the allowable control in actual use. Bandwidth, insufficient robustness of system parameters

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