可升压自然软开关DC/AC逆变器电压控制特性分析

提出三相逆变器线电压调制度概念,避开了相电压的零序分量对传统相电压调制度的影响,更有利于从伏秒面积相等的概念出发理解脉宽调制的本质.指出无论采用何种调制模式,如果在线性调制范围内要获得幅值高于给定输入直流电压的三相对称正弦波输出交流电压,必须增加一级直流环节的升压电路.以此为基础,提出了一种特殊的升压电路拓扑,介绍了该电路的基本工作原理,详细分析了该拓扑特有的控制方案和升压特性,为该拓扑在不同工作场合工作模式的正确选择打下坚实的理论基础.实验证明新型拓扑具有良好的工作特性.

Voltage Control Character of the Natural Soft-Switching Two-Level DC-AC Power Converter With Adjustable DC Link Voltage

This paper defines a line-line voltage modulation for the three-phase inverter. It avoids the effect of the zero-sequence component of phase voltage in the conventional modulation, and makes it easy to explain the essence of the pulse width modulation. Based on this definition, it is easier to understand that in the linear modulation range to obtain a higher output line-line AC voltage, a kind of boost circuit should be inserted between the DC source and the three-phase inverter. A novel boost circuit is presented with its basic operation. Analysis about its special voltage character is carried out in detail, which will be benefit to select its right operation for the different applications. Experimental results will be presented to demonstrate these new features of this topology.