矩阵变换器的电压型两步换流策略

分析了基本的电压型两步换流策略，在输入两相电压值接近(电压换区间)时刻，由于输入相电压的相对大小判断错误而导致输入相的短路现象以及原因。为此，提出了基于电压型两步换流策略的矩阵变换器控制方法，通过引入过渡区间，并在过渡区间内定义新的P、M、N状态和PM、MN、NP暂态以及调整过渡区间中每个调制周期的零矢量和双向功率开关状态换流次序，可以避免输入相电压在过渡区间因判断不准确而出现的短路现象，实现矩阵变换器安全、可靠的两步换流和稳定运行，且输出电压波形和输入电流波形不受影响。在5 kW矩阵变换器实验样机上进行了大量的实验，实验结果表明，所提出的控制方法可实现矩阵变换器电压型两步换流和安全运行，而不需要外加专门的精确检测输入相电压相对大小关系的测量装置，控制电路简单易行。

Two-step Commutation Strategies for Matrix Converter

Short circuit phenomenon will happen because of using the traditional two-step commutation strategies, when the magnitude of two input phase voltages is adjacent which may cause polarity misjudgment. Based on two-step commutation strategies, a control method for matrix converter (MC) was proposed to make MC commutation safety and stability. By using the intermediate intervals, defining new commutation steady states (P, M, N) and new commutation temporary states (PM, MN, NP), selecting special zero vectors and changing subsequence of vectors, the short circuit phenomenon in the intermediate intervals can be avoided because of the polarity misjudgment of input line voltage. The method has little influence on input currents and output voltages. Experimental results of 5 kW MC prototype verify the validity and feasibility of the safe commutation method. The power equipment need not precise circuit to detect the polarity of input line voltage and the control circuit is easy to realize.