基于空间电压矢量PWM控制的磁轴承开关功放

Magnetic bearing switching power amplifier based on SVPWM control

针对传统开关功放驱动多自由度磁轴承体积大、功耗大的缺点,设计了一种新型磁轴承功放。该功放采用了三桥臂主电路拓扑结构以及空间矢量PWM控制策略,利用六个功率开关管的八种开关状态相对应的基本电压空间矢量来逼近磁轴承线圈的电压,根据线圈空间电压矢量切换来对其电流进行控制。这种功放能够提供双极性的电流驱动,同时驱动磁轴承两个自由度的绕组,该功放驱动的磁轴承线圈电压具有三态,具有三电平功放低纹波电流的优点。仿真和实验结果表明,该功放可以独立的对两路输出电流进行控制,并且能够控制其很好地跟踪给定信号。与传统类型的磁轴承开关功放相比,减小了体积和开关损耗,提高了可靠性,特别适合于空间环境应用。

A magnetic bearing 3-leg switching power amplifier is applied for solving the problem of volume and power loss while using the conventional switching power amplifier in magnetic bearing control system. A space vector pulse width modulation （SVPWM） control method is applied in the new circuit design and then the magnetic bearing voltage is approached by the basic voltage space vector corresponding to 8 switch-status of 6 power switching tubes, which control coil current by switching the magnetic bearing coil space voltage vector. The amplifier can supply bipolar circuit drive and drives 2 freedoms magnetic bearing coil simultaneously. The magnetic bearing coil voltage derived by the amplifier has merits of three-state and the low current ripple three- level modutation. Simulation and experiment prove that 2 outputs current can be controlled individually and trace the given signal accurately. Compared with the conventional magnetic bearing switching power amplifier, the volume and switching loss is reduced, and the reliability is higher. It can apply in space application better.