Low-carrier-wave-ratio dead-beat control system and method for permanent magnet synchronous motor

Abstract

The invention discloses a low-carrier-wave-ratio dead-beat control system and method for a permanent magnet synchronous motor. The system comprises the permanent magnet synchronous motor, an encoder,an abc-dq coordinate conversion unit, a rotating speed outer ring PI controller, a 1 / 2 moment current estimation unit, a current dead-beat controller, a dq-alpha beta coordinate conversion unit, an SVPWM modulation module and an inverter. In the process of building a current prediction model, the inverter and the motor are regarded as a whole for building the model, the delay action of the inverter is considered, and 1 / 2 moment current estimation is added for correcting a discretization error, so that the built model is more accurate than a traditional current prediction model; and a current error decoupling integral compensation module is added into the dead-beat controller, so that a stator current control offset is greatly improved, the purpose of good dead-beat control under a low-carrier wave ratio is achieved finally, and a result shows that the motor speed and stator current control is good, the motor stator current control offset is relatively small, and the output torque pulsation is also improved.

Description

technical field [0001] The invention relates to a low-to-carrier-ratio deadbeat control system and method for a permanent magnet synchronous motor, belonging to the technical field of motor control. Background technique [0002] Due to the limitation of switching loss, the high-power permanent magnet synchronous traction motor drive system has to use low switching frequency (such as about 500Hz) to control the driving motor in reality, which makes the ratio of switching frequency to current frequency, that is, the carrier ratio, low. [0003] At present, permanent magnet synchronous motors generally use dual-PI vector control strategies, but at low switching frequencies, the system sampling delay will be greatly increased, which will destroy the dynamic decoupling in the vector control system, and the motor control is difficult to meet the control requirements, and the output stator The current contains a large number of harmonics, which makes the output torque of the motor ...

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Problems solved by technology

[0006] In order to solve the deficiencies in the prior art, the object of the present invention is to provide a low-carrier-ratio deadbeat control system and method for permanent magnet synchronous motors, which solves the control effect of traditional permanent magnet synchronous motor deadbeat control systems at low switching frequencies. Poor, large current static difference, large output torque ripple, etc., realize the good control effect of deadbeat control strategy at low switching frequency, and the current control static difference is also small

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