一种新型的磁悬浮轴承五相六桥臂开关功率放大器控制策略

A Novel Control of Five-Phase Six-Leg Switching Power Amplifier in Magnetic Levitating Bearing System

针对磁悬浮轴承系统电流型五相六桥臂开关功率放大器控制算法复杂以及各路输出电流存在耦合的问题,提出一种新型的五相六桥臂开关功率放大器的解耦控制策略。该方法固定公共桥臂占空比为0.5,以单周期控制的方式,同时控制每路负载线圈电流的周期变量平均值等于给定电流周期变量平均值,实现电流的独立输出与解耦控制。推导了该控制方法的数学模型,并制作了试验样机,仿真和实验结果均表明,基于该控制方法下的五相六桥臂开关功率放大器实现了各相的独立控制,并具有控制简单、运算量小、响应速度快、控制精度高和通用性强的优点。

The traditional current control algorithm for the five-phase six-leg switching power amplifier in the magnetic levitating bearing system is complicated and different phase currents are intercoupling. To address this problem,a novel decoupling control strategy is proposed in this paper. This method sets the duty cycle of the neutral leg as 0. 5,which ensures that the average current of each phase is equal to the reference in each control cycle and realizes the independent and decoupling control for the output currents. The mathematic model of the system is built,and the prototype is constructed to test this method. Both the simulation and experimental results have demonstrated that the five-phase six-leg output currents can be controlled independently. The proposed method has the advantages of easy control,less computation,quick dynamic response,high accuracy,and strong universality.