矩阵变换器输入功率因数可调时的换流控制策略

矩阵变换器的电压型两步换流策略具有换流过程快,开关损耗小,不受运行工况影响,控制系统结构简单等优点。针对该方法在输入电压换区间时易发生短路的现象,一些文献提出了一种带有过渡区间的电压型两步换流策略,较好地解决了矩阵变换器在较大功率输出条件下的换流问题,但是该方法只适用于输入功率因数为1附近的情况,当输入功率因数变化较大时,系统仍会发生短路问题。为此,本文在具体分析换流过程的基础上,提出了适用于输入功率因数可调时的换流方法,在过渡区间内通过判断电压的相对大小,使用换序法将大压差电压调整至调制顺序的中间,避免了换流时可能出现的短路现象,进一步完善电压型两步换流策略。最后,仿真和实验结果表明本文所提出的改进策略是正确可行的。

Commutation Strategies of Matrix Converter with Adjustable Input Power Factor

Voltage-controlled two-step commutation strategies of matrix converter have excellent characteristic such as fast commutation,low switching loss,hard to disturb and easy to control.But short circuit phenomenon will happen when the instantaneous value of two input phase voltages is adjacent.A kind of voltage-controlled commutation method using the intermediate intervals is proposed to solve short circuit in some literatures.This method is only used when input power factor is near to 1.Short circuit will inevitably happen when input power factor is adjustable.An advanced method applied to adjustable input power factor is proposed in this paper based on the commutation process analyzed.By measuring the instantaneous value of input voltages,changing high differential voltage to the middle of the modulation subsequence,the proposed method can avoid short circuit,ensure safe commutation and consummate voltage-controlled commutation strategies.Simulation and experimental results verify the validity and feasibility of the proposed commutation method.