三态空间电压矢量分布三桥臂开关功放的控制
A Control Method of Switching Power Amplifiers with Triple？？Arm SVPWM

针对传统电磁轴承开关功放采用两路独立的H桥控制结构存在的体积庞大、功率损耗高等缺点,以空间电压矢量分布(space voltage pulse？？width modulation,SVPWM)控制理论为基础,结合H桥三电平控制的优点,提出一种三电平三桥臂功率放大器的实现方法。该方法通过对不同结构载波的选择分别设计了基于对称结构、非对称结构下SVPWM主动电磁轴承开关功放的控制算法,对比分析了在不同载波结构下纹波电流的特性,并在Matlab/Simulink环境下构建出两种原理性仿真模型。在dSPACE实时仿真系统下搭建出一个三桥臂功放电路控制平台,并对两种不同结构下功率系统的频率特性进行了测试。理论与实验结果表明,基于对称结构的三态SVPWM控制算法,不仅可有效地提高电流响应速度,而且还能够使纹波电流频率加倍、纹波幅值显著减小,当频率为1 750 rad/s时,其系统增益仅为-3 dB。因此,该方法在满足电磁轴承系统低纹波电流和良好动态特性要求的同时也提高了主动电磁轴承系统的可靠性性能。
A novel triple？？arm switching power amplifier based on SVPWM theory is proposed to solve the problem that the traditional AMB (active magnetic bearing) that is controlled by two H？？bridge switching power amplifiers have some shortcomings such as bulky size, high power consumption. The amplifier bases on the theory of SVPWM and the advantage of three？？level control. Both symmetrical and asymmetrical SVPWM theories are applied for different carriers. Two different methods of SVPWM switching power amplifiers are established in the Matlab/Simulink environment and a novel three？？leg switching power amplifier circuit system is realized by dSPACE. Both the theoretical results and experiment results show that the symmetrical SVPWM control algorithm improves the current response speed effectively, doubles the ripple current frequency and decreases its amplitude significantly. When the frequency is 1 750 rad/s, the system gain is only －3 dB. Thus the method meets the requirements of low ripple current and good dynamic, and improves the reliability of AMB system performance