Control system for low-speed running of permanent magnet motor

Abstract

The invention discloses a control system for low-speed running of a permanent magnet motor, which consists of a speed controller, a current loop, an angle sensor, a disturbing estimator, a tooth socket torque estimator and a tooth socket torque calculator. The sizes of the tooth socket torque and the rest resisting moments are quickly calculated by the disturbing estimator and the tooth socket torque estimator; the influence of the tooth socket torque on the speed is further accurately calculated through the tooth socket torque calculator so as to make compensation; the stability of the control system is increased by controlling integral coefficients of the speed controller in real time, and equivalently, output current is changed through changing the integral coefficients to compensate for aperiodic resisting moments at the same time; and the response speed of the control system is increased by carrying out the advanced compensation of the delay of the controller so that the disturbance is quicker to attenuate. The control system has higher correctness and stability, and is particularly suitable for realizing the low-speed control of the permanent magnet motor under the condition of the larger change range of the resisting moments.

Description

technical field [0001] The invention relates to a motor control system, more specifically, the invention relates to a control system for permanent magnet motors running at low speed. Background technique [0002] Cogging torque is an inherent phenomenon of permanent magnet motors. Due to the existence of cogging, the output torque of the motor fluctuates, which affects the accuracy of the control system. This phenomenon is especially obvious at low speeds. In addition to improving the structure of the motor in the existing technology, the suppression of the cogging torque is mainly to increase the compensation measures for the cogging torque in the control algorithm in the control system, so as to reduce the fluctuation of the motor speed. For example, the system introduced in the article "Research on Low-speed Cogging Torque Ripple Compensation of Direct Drive Annular Permanent Magnet Torque Motor" on pages 21-24 of the third issue of "Electrical Technology" in 2009, consis...

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Problems solved by technology

[0003] The disadvantage of this control system is that it does not consider the influence of other resistance torques except cogging torque

Since the cogging torque is a periodic disturbance, other resistance torques such as friction torque or elastic resistance torque can be regarded as non-periodic disturbances. The impact of non-periodic disturbances on the delay of the control system is not the same as that of periodic disturbances. A single estimate The device cannot accurately restore the phase of external disturbances. In the case of a relatively large range of external disturbances, the error caused by the phase will be relatively large.

In addition, if the variation range of the non-periodic disturbance is relatively large, the overshoot of the control system is also constantly changing, which reduces the stability of the control system, limits the maximum bandwidth that the control system can obtain, and reduces the response speed of the control system.

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