电磁轴承脉宽调制型开关功放的实现及电流纹波分析

传统两电平脉宽调制电磁轴承开关功放的电流纹波较大,导致电磁轴承中产生的纹波损耗较大.采用一种三电平脉宽调制方法,对电磁轴承开关功放电流纹波进行理论分析,结果表明该方法能够大大减小开关功放的电流纹波,具有传统两电平脉宽调制输出波形质量好、动态响应快等优点,且实现简单.最后通过计算机仿真和实验对该方法进行了验证,仿真与实验结果说明了该方法的可行性和有效性.

Analysis of Current Ripple and Implementation of Pulse Width Modulation Switching Power Amplifiers for Active Magnetic Bearing

A three-level pulse width modulation (PWM) switching power amplifier for active magnetic bearing applications is implemented in the paper. Different from conventional two-level PWM switching power amplifier, the switching power amplifier can achieve current ripple reduction. Then an analytical method for computing the current ripple is presented. The current ripple amplitude of the three-level PWM switching power amplifier is compared with that of the two-level PWM switching power amplifier. Comparative results indicate that the three-level PWM techniques can effectively reduce the current ripple in theory. The method of control has the advantages of conventional two-level method with good output wave and fast dynamic response and it is simple to be implemented. By using a practical switching power amplifier as an illustrative example, which works in two different PWM techniques, numerical simulation and experimental method are implemented. The consistency of the final simulation results with the experimental results further indicates the feasibility and effectiveness of the used control strategy.