Model predictive current overmodulation control method for two-level brushless direct current motor

Abstract

The method comprises the following steps: firstly, acquiring three-phase stator current and an electrical angle of a rotor at a moment k through a current sensor and an encoder, and calculating three-phase counter electromotive force according to a piecewise linear method; calculating a current prediction component of the three-phase current under a dq coordinate at a k sampling moment through coordinate transformation, and further calculating a current prediction value of the three-phase current under a dq axis coordinate at a k + 1 sampling moment through a first-order Euler equation; taking the dq current as a control object, and constructing a value function related to the dq current; then, the optimal voltage vector, the secondary optimal voltage vector and the zero vector jointly act on a sampling period, so that the dq-axis current error is zero, and the action time t1, t2 and t0 of the optimal voltage vector, the secondary optimal voltage vector and the zero vector are calculated through the Cramer rule; through switching of the operation modes, the rotating speed range of the brushless direct current motor is expanded, the direct current bus voltage utilization rate is improved, and meanwhile better dynamic and steady state performance can be obtained.

Description

technical field [0001] The invention relates to a two-level brushless DC motor model prediction current overmodulation control method, which belongs to the field of motor drive and control. Background technique [0002] Traditional DC motors use brushes to achieve commutation mechanically. During the commutation process, noise, sparks, and radio interference will be caused by friction, which shortens the life of the motor. In addition, its manufacturing cost is high and maintenance is difficult. Its scope of use is extremely limited. Brushless Direct Current Motor (BLDCM) is a high-performance motor developed on the basis of brushed DC motors. Brushless DC motor has the advantages of high power density, good speed regulation performance, high structural reliability and relatively simple control, so it has been widely researched and applied. The field of production and inspection equipment widely used by brushless DC motors such as centrifuges and agitators is developing in...

AI Technical Summary

Problems solved by technology

The phase advance method achieves speed expansion by turning on a certain phase in advance of the switch tube, but this method will cause the motor current to be too large, increase the heat generation of the motor, and increase the heat dissipation cost of the motor

The back EMF offset method uses the inverter back EMF to offset the rotation back EMF, but this method increases the complexity of the motor design

The instantaneous power method utilizes the relationship between instantaneous reactive power and rotational speed to achieve speed expansion. Since reactive power needs to be detected in real time, this requires high processing power of the CPU, and the speed expansion effect is not obvious.

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