双Buck电压源逆变器的半周期电流调制方法

Half Cycle Current Modulation Method for Dual Buck Voltage Source Inverter

双Buck逆变器由于消除了桥式逆变器的直通问题并优化设计了续流二极管,效率及可靠性都得到了很大的提高。传统的用于双Buck逆变电路的斜坡比较控制采用带偏置电流的控制方式,导致效率较低。采用滞环控制半周期电流调制方式消除了偏置电流,提高了效率,但是开关频率的变化不利于输出滤波器的设计。本文首先分析了电流半周期调制方式下双Buck逆变器的四象限运行方式及半周期调制原理,提出采用单电流互感器采样的恒频斜坡交截控制。对斜坡交截控制和滞环控制的稳态和动态性能进行了比较,并对有偏置电流和无偏置电流斜坡交截两种控制方式进行了频谱分析。仿真和实验结果表明了理论分析的正确性。

Dual Buck inverter＇s efficiency and reliability have been greatly improved due to the elimination of the shoot-through problem of bridge inverter and optimization of the freewheeling diode. Traditional control method used for dual Buck inverter is ramp compare method with bias current which leads to poor efficiency. To improve the efficiency, traditional half cycle modulation hysteresis control is adopted. But the output filter is difficult to design due to the varying switching frequency. In this paper, the four quadrants operating modes of dual Buck inverter under the current half cycle modulation are analyzed, and single current sampler constant ramp compare control method is proposed through the analysis of current half cycle modulation which eases the filter design and reduces the cost of the control. The steady and dynamic performance are compared between ramp compare and hystereis control, and the spectrum analysis is made for biased and unbiased control. The simulation and experimental results prove the correctness of the theoretical analysis.