Permanent magnet motor model prediction control method with fixed switching frequency

Abstract

The invention discloses a permanent magnet motor model prediction control method with a fixed switching frequency. The method comprises the following steps: building a mathematical model of a permanent magnet motor and a driving converter system of the permanent magnet motor, and obtaining the current of the motor, a DC bus side voltage value, and an inverter output voltage value; establishing a discretization stator current prediction model under a rotating coordinate system, and predicting the current value of the motor at the next moment after performing one-step compensation on the system time delay; establishing a switching period discretization model equivalent to the switching frequency of the IGBT, counting switching actions of the device, and predicting a switching period value; and establishing a total cost function, determining a switching state, and outputting and controlling on and off of an inverter switching tube. Switching signals are not generated through modulation, the control structure is simple, the operation load is low, the effects of constant switching frequency and neutral point potential balance are achieved at the same time, the control effect can be globally optimal, and the permanent magnet motor can have low torque ripple and high dynamic response at the same time during operation.

Description

technical field [0001] The invention relates to the technical field of permanent magnet motor control, in particular to a model predictive control method for a permanent magnet motor with a fixed switching frequency. Background technique [0002] The continuous innovation of the traction system is the key to the technological progress of rail trains, and it is also an important and difficult point to realize the autonomy of high-speed rail technology. The traction system is the "heart" of a high-speed train, and its performance determines the starting, braking and maximum speed of the train. Green and high efficiency is the eternal goal of the development of rail transit traction systems. Compared with asynchronous motor traction systems, in recent years, permanent magnet synchronous motors (Permanent Magnet Synchronize Motor, PMSM) have low loss, high efficiency, low noise, and high power density. , good starting characteristics, strong acceleration ability and other advan...

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Problems solved by technology

[0005] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a model predictive control method for a permanent magnet motor with a fixed switching frequency, which solves the problem that the switching frequency of the existing FCS-MPC is not fixed, making it more suitable for high-power permanent magnet motors At the same time, it can take into account the dynamic response performance and torque ripple performance of permanent magnet motors, further reduce the switching loss of power devices when FCS-MPC is used in high-power permanent magnet traction systems, and can effectively estimate the heating range of the system, which is beneficial to the traction system The heat sink and output filter design of the

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