Flexible permanent magnet brushless direct current motor control system and control method thereof

Abstract

The invention discloses a flexible permanent magnet brushless direct current motor control system, which comprises a direct current power supply, a filter capacitor, a voltage source inverter, a permanent magnet brushless direct current motor and a controller, the output end of the direct-current power supply is connected with the filter capacitor; the voltage source inverter is provided with m bridge arms which are connected to the two ends of the filter capacitor in parallel; an upper controllable switching device and a lower controllable switching device are arranged on each bridge arm; thephase number of armature windings of the permanent magnet brushless direct current motor is equal to that of the bridge arms; the head end of each phase armature winding is correspondingly connectedwith the middle connection point of the upper controllable switch device and the lower controllable switch device of one bridge arm; the tail ends of all phases of armature windings are connected together; equally dividing the electric period of the permanent magnet brushless direct current motor into a plurality of sectors; and the controller determines sectors corresponding to the N pole and theS pole according to the position of the rotor, and outputs a control signal to drive the corresponding controllable switching devices to be switched on and off. The invention further discloses a speed regulation method of the flexible permanent magnet brushless direct current motor. Graded speed regulation is achieved according to different conduction modes and pulse width modulation.

Description

technical field [0001] The invention relates to a control system and a control method of a brushless direct current motor, in particular to a control system and a control method of a flexible permanent magnet brushless direct current motor. Background technique [0002] At present, the permanent magnet brushless DC motor uses electronic commutation technology to replace the brush commutation of the traditional DC motor, which retains the superior performance of the DC motor, such as large starting torque, fast response to speed regulation, etc., and also has the structure of an AC motor It has the advantages of simplicity, convenient maintenance and reliable operation, and the rotor uses permanent magnet materials for excitation without excitation loss. With the in-depth research on new permanent magnet materials and power electronics technology, the production and application of brushless DC motors in the national economy has been greatly improved. At present, it has been ...

AI Technical Summary

Problems solved by technology

Taking the three-phase six-state permanent magnet brushless DC motor drive as an example, the current in the armature winding switches from one phase to another every time the motor passes through a conduction state. Due to the inductance of the armature winding, the current in the armature winding During commutation, the current change rate of the current rising phase and the current decaying phase are different, which causes the electromagnetic torque of the three-phase current synthesis to change, thereby causing torque fluctuations

[0004] The three-phase permanent magnet brushless DC motor drive circuit mainly adopts the three-phase full-bridge inverter circuit. This topology has the advantages of simple structure, convenient control and fewer controllable switches. Multiple controllable switches are required to be connected in parallel on the arm, which is prone to uneven current distribution and lead to failure, which affects the reliability of the system

Images