恒磁通步进式脉宽调制变频电源研究

设计了一种恒磁通步进旋转式脉宽调制变频电源,该电源的斩波脉冲宽度数据是根据等面积原理计算所得的在60°的两相数据,其输出波形保持了电动机磁通的恒定,同时在每个斩波的两端磁通方向保持不变。在输出标准脉宽调制(PWM)正弦波时,可使谐波畸变率小于5%。工作时只有2/3周期为双极性波形,1/3周期为单极性波形,可使功率三极管总功耗降低1/3。频率降低时,脉宽数据不变,可获得与频率成比例下降的输出电压,达到了变频变压保证电机磁路不饱和及恒转矩输出的目的。该电源可广泛用于机械、冶金、化工、轻工等领域。

Research on Variable Frequency Power Supply Based on Permanent Magnetism Step Pulse Width Modulation

A variable frequency power supply on permanent magnetism step rotation pulse width modulation(PWM) is introduced.According to the equal-acreage principle,the computed width data of the chopped pulse of the frequency conversing power gets two-phase data in 60°,and the output wave of this mode makes the motor magnetism constant,while magnetism direction on two terminals of each chopped wave keep invariable.If theoretic output pluse is 100% standard PWM sine wave,the harmonic distortion can be less than 5%.When the power supply is working,with the double polar wave in 2/3 cycle and single polar wave,then the total power wastage can be reduced by 1/3.If the frequency is depressed and the pulse width is kept,the output voltage decreacing in proportion to the frequency's fall can be got,so as to realize variable frequency,variable voltage and to make the output of the motor magnetic circuit unsaturated and torque constantly.The power can be widely applied in the fields of machinery,metallurgy,chemical industry,light industry,etc.