一种模块化48脉冲大功率PWM逆变器

多脉冲逆变器通过移相变压器原副边移相角度的精确设计,可以在工频开关方式下,实现交流侧阶梯波输出,经过滤波得到高质量的正弦波形,但工频开关方式使其输出调压困难,而且随着脉冲数的提高,逆变器连接的变压器结构复杂,多个绕组之间的匝比难以兼顾,因此实际应用中多脉冲逆变器的通道数多在4以下。提出一种只有两个规格移相变压器结构的模块化48脉冲大功率PWM逆变器,该逆变器具有8个通道的三相逆变器和对应移相变压器组成,且每个三相逆变器采用低频PWM调制策略,实现输出电压调节。构建了一台8通道48脉冲的PWM逆变器样机,在各种运行状态下的输出波形以及相关测试数据验证了所提出的模块化多脉冲逆变器在输出波形、开关频率以及输出调节特性等方面的优势。

A Modular 48-pulse high-power PWM inverter

Multi-pulse inverter can output staircase wave under low switching frequency mode with the secondary winding of phase shift transformer turn ratio accurately design, and then, the high quantity sine wave can be obtained at the AC side of the inverter after filter. But suffering from the fundamental switching mode, the output voltage regulation of multi-pulse inverter is difficult. Moreover, as the number of its pulse increased, the structure of the phase shift transformer becomes complex and the winding turn ratio of transformer cannot be designed accurately. The channel number of the multi-pulse inverter is usually below four in actual application. This paper presents a modular 48-pulse high-power PWM inverter with only two kinds of phase shift transformer which has the structure of 8-channel three-phase inverter and phase shift transformer accordingly. The proposed inverter shows great virtue of voltage regulation benefited from low switching frequency PWM modulation strategy. A 50 kilowatts 8-channel mutli-pulse inverter prototype is constructed, and the test data and waveform in many operating modes validated the advantages of the proposed modular multi-pulse inverter in output waveform, switching frequency and regulation performance etc.