矩阵变换器改进的双电压控制策略

Improved control strategy of double line-to-line voltages for matrix converter

针对矩阵变换器双电压控制策略中开关状态转换过程复杂、软件实现困难的问题,提出了一种改进的控制策略。将输入、输出电压各划分为12个区间,并根据一定原则对三相输入、输出电压进行变量定义。输入、输出电压区间的组合情况被分成4种进行讨论,在每一种情况下,占空比的表达式是统一的。详细推导并分析了这4种情况下各个占空比的大小关系,归纳总结成2种情况,具有固定的大小关系。根据各个占空比的大小,考虑开关状态的转换,绘制出了2种情况的PWM顺序图,简化了双电压控制策略的实现,并且使得开关状态的转换次数最少。研制了实验原理样机,用实验验证了改进控制策略的正确性和可行性。

An improved control strategy of double line-to-line voltages is proposed for matrix converter,which simplifies the conversion operation of switching state.The input and output voltages are divided into twelve sectors respectively and their variables are defined according to a certain principle.Their sector combinations are discussed in four patterns and each has unified duty-cycle expression.The relations of duty cycle of these patterns are analyzed respectively and summarized to two conditions with fixed relation.The conversion operations of switching state are considered based on the fixed duty-cycle relation and the switching sequence of PWM is drawn for two conditions,which simplifies the implementation of control strategy and minimizes the switching times.Its validity is verified by experiments.