Vehicle permanent magnet synchronous motor vector field weakening control system considering torque precision

Abstract

The invention discloses a vehicle permanent magnet synchronous motor vector field weakening control system considering torque precision. The system comprises a current closed-loop adjustment module, a modulation ratio deviation calculation module, a current instruction angle compensation module, a current angle presetting module, a current instruction angle limit comparator, a current given amplitude compensation module and a current given vector correction module. The adjustment direction is always weak magnetic direction, and instability caused by repeated adjustment is avoided; the dq current is introduced and corrected at the same time, so that the anti-voltage saturation pressure can be shared to the dq current, and the situation that the output torque deviation is too large due to too much adjustment of the single-axis current is avoided; according to the method, the torque precision is ensured while the traditional weak magnetic target which is controlled by the system and does not lose stability is ensured.

Description

technical field [0001] The invention belongs to the field of permanent magnet synchronous motor control, and in particular relates to a vehicle permanent magnet synchronous motor vector field weakening control system considering torque accuracy. Background technique [0002] In the vehicle embedded permanent magnet synchronous motor (IPMSM) control system, due to the inevitable change of the controlled object - IPMSM in the actual application scene, the pre-cured control parameters in the control program are invalidated, resulting in the motor running at high speed and weakening the field Insufficient voltage causes voltage saturation, which jeopardizes the stability of the motor drive system. [0003] The embedded permanent magnet synchronous motor has the characteristics of high power density, wide operating range and high efficiency, and is widely used in the drive motor of electric vehicles; its torque equation is: [0004] (1) [0005] in, is the electromagnetic ...

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Problems solved by technology

[0018] 1. When the motor is in mass production, the process and materials will inevitably lead to the inconsistency of the motor;

[0019] 2. When there is a deviation in the resolver offset of the motor, even when the current regulator is working normally, it will cause a deviation in the orientation of the magnetic field on the control, which will cause the actual dq current in the motor to be inconsistent with the expected current command;

[0020] 3. Changes in ambient temperature will affect the flux linkage of permanent magnets. When the temperature drops, it will cause As a result, the calibrated dq current command no longer satisfies the voltage limit

According to formula (3), when )>0, increase the negative i d , can reduce the output voltage, that is, this scheme is effective; but when )d , will make The reverse increase will cause the output voltage to further increase, which will cause the voltage saturation to be more serious; therefore, when using this method, it must be ensured that )>0

However, in vehicle motor control, if this limitation is added, the reluctance torque of the motor in the high-speed region will not be fully utilized, sacrificing the performance of the motor

In the above scheme, reduce i when the voltage is saturated d The method can deepen the weak magnetic field and make the motor exit the voltage saturation state, but this method has a great impact on the output torque, because only by correcting i d , requires a larger i d Correction amount, the combination of dq current changes greatly, so that it has a great impact on the output torque

Non-Patent Literature (T.M. Jahns, "Flux Weakening Regime Operation of an Interior Permanent-Magnet Synchronous Motor Drive", IEEE Trans. on Ind. Appl., vol. IA-23, no. 4, pp. 55-63, 1987) A method is proposed to reduce the i q method, but only adjusting a single current also faces the problem of having a large impact on the output torque

No good existing technology has been found that can effectively deal with the voltage saturation problem and have as little impact on the output torque as possible

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