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1.引言 随着电气传动技术,尤其是变频调速技术的发展,作为大容量传动的高压变频调速技术也得到了广泛的应用。近年来,各种高压变频器不断出现,电压源型高压变频器具有运行稳定、调速范围宽、输出波形好、输入电流谐波含量低、功率因数高和效率高等优点,应用较为广泛。本文对三电平PWM变频器和单元串联多电平PWM变频器二种应用较为普遍的电压源型高压变频器进行分析比较,指出各自优缺点。 2.三电平PWM电压源型变频器 在PWM电压源型变频器中,当输出电压较高时,为了避免器件串联引起的动态均压问题,同时降低输出谐波和dv/dt,逆变器部分可以采用三电平方式,也称中心点钳位(Neutral Point Clamped:NPC)方式,如图1。逆变部分功率器
1. Introduction With the development of electric drive technology, especially frequency conversion speed regulation technology, it has been widely used as a high-voltage frequency conversion speed regulation technology for high-capacity transmission. In recent years, a variety of high-voltage inverter constantly appear, voltage source high-voltage inverter with stable operation, wide speed range, the output waveform is good, the input current harmonic content is low, high power factor and high efficiency, the application is more extensive. This article analyzes and compares two kinds of voltage-source type high-voltage inverters, which are generally used in three-level PWM inverter and series-connected multi-level PWM inverter, and point out their respective advantages and disadvantages. 2. Three-level PWM voltage source inverter In the PWM voltage source inverter, when the output voltage is high, in order to avoid the device caused by the series voltage dynamic voltage balance, while reducing the output harmonic and dv / dt, inverter Part of the device can be three-level mode, also known as the center point clamp (Neutral Point Clamped: NPC) approach, shown in Figure 1. Inverter part of the power device