A control method of electric bicycle based on permanent magnet brushless DC motor

Abstract

The invention discloses an electric bicycle control method based on a permanent magnet brushless direct current motor. According to the method, subdivided rotor position information is used for directly starting the motor, and the switching procedure from square wave starting to sine wave starting in a traditional control method is omitted. The electric bicycle control method relates to a rotor section calculation module, a speed calculation module, an angle subdivision module, a phasing adjustment module, a speed control module, a current-limiting control module, a waveform modulation module, a three-phase inverter and a motor starting module. By the adoption of the method, control efficiency and control performance are improved, and currents passing through a motor winding are in a sine wave mode when the motor operates; compared with a traditional square wave control method, torque pulsation is small, motor running noise is low, and the service life of the motor can be prolonged; compared with a traditional space vector control method, the algorithm is simple, implementation is easy, the requirement for a microprocessor is low, and high cost performance is achieved.

Description

technical field [0001] The invention relates to a control structure and method of an electric bicycle, in particular to a control structure and method of an electric bicycle based on a permanent magnet brushless DC motor. Background technique [0002] Permanent magnet brushless DC motors are widely used in industrial fields such as household appliances, instruments and meters, and medical equipment due to their simple structure, reliable operation, convenient maintenance, high efficiency, no excitation loss, and good speed regulation performance. [0003] The control method of permanent magnet brushless DC motor is generally square wave (or trapezoidal wave) control. This control method is simple and easy to implement. However, since the stator current and air gap flux are square waves or trapezoidal waves, the torque ripple is large. The mute effect is poor, and the motor control efficiency is not high. However, some of the existing control methods are based on square wave...

AI Technical Summary

Problems solved by technology

[0003] The control method of permanent magnet brushless DC motor is generally square wave (or trapezoidal wave) control. This control method is simple and easy to implement. However, since the stator current and air gap flux are square waves or trapezoidal waves, the torque ripple is large. The mute effect is poor, and the efficiency of motor control is not high

However, some of the existing control methods are based on square wave control to compensate the motor current, which cannot fundamentally eliminate pulsation and reduce noise; Low; there are also space vector control methods, which have higher requirements on the single-chip microcomputer, and the algorithm is very complicated, which is not conducive to actual operation.

[0004] Permanent magnet brushless DC motor sine wave control generally needs to be switched from square wave start to sine wave control when starting. This control method requires an additional start-up procedure, which is not conducive to improving control efficiency and system performance.

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