| Be provided with celerity start-up and good mechanical characteristic and longevity and high dependability and low noises, the brushless-motor are used widely in high-precision and high-powered mechanical and electronic control system.The point of Pulse Width Modulation—PWM is a technic of using a set of ordinal pulse to obtain requisite voltage waveform which form and amp could be changed. Using this technic,three-phase brushless-motor would be endued with higher efficiency and wider timing range. it would achieve more nicety current and control either. So this technic is the mainstream research way of brushless-motor driver.There is a kind of interplay between the positive control and negative feedback exist in controllable quantity and under control quantity, namely, under control quantity is controlled by controllable quantity utilizing control function, while the under control quantity is feed back to the input port of closed up system. After compared with the input signal, we can get a amended quantity. thereby correct error of the closed up system. Which we call closed up system feedback.The text designed a kind of brushless-motor driver of 3 phases using hybria encapsulation based on the system feedback theory and the application of PWM theory in electromotor control. The brushless-motor driver can control and drive the brushless-motor, and it is provided with high voltage and current, as well as 100% duty cycle and over current protection. The text mainly explains:1.Carry on an investigation in unearthly status, the relationship of control signal in the part of the export. And raised a way to control the the high and low transistor, avoiding the part of export burn in case of “common state short circuit”. based on the way, we realize the design of dead time.2.Carry on an investigation in respond speed of feedback control, to a higher slope of control. Based on the error amp in current feedback circuit, the text adopted dc current unclosed loop,to solve unstable in zero point of the driver because of the dithering of voltage when the control signal is zero, which may cause the driver outputs the excessively voltage or current in positive or negative. |
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