TABLE OF CONTENTS As described in Chapter 3, all DC/AC pulse-width-modulation (PWM) inverters are treated as a first-order-hold (FOH) element in digital control systems. We will discuss this model in various circuits in this Chapter.
DC/AC inverters are a newly developed group of the power switching circuits applied in industrial applications in comparison with other power switching circuits. Although choppers were popular in DC/AC power supply long time ago, power DC/AC inverters were used in industrial application since later 1980s. Semiconductor manufacture development brought power devices, such as gate turn-off thyristor, Triac, bipolar transistor, insulated gate bipolar transistor and metal-oxide semiconductor field effected transistor (GTO, Triac, BT, IGBT, MOSFET, respectively) and so on, in higher switching frequency (say from thousands Hz upon few MHz) into the DC/AC power supply since 1980s. Due to the devices such as thyristor (silicon controlled rectifier, SCR) with low switching frequency, the corresponding equipment is low power rate.
Square-waveform DC/AC inverters were used in early ages before 1980s. In those equipment thyristors, GTOs andTriacs could be used in low-frequency switching operation. High-frequency/high-power devices such as power BTs and IGBTs were produced in the 1980s. The corresponding equipment implementing the PWM technique has large range of the output voltage and frequency, and low total harmonic distortion (THD). Nowadays, most DC/AC inverters are DC/AC PWM inverters in different prototypes.
DC/AC inverters are used for inverting DC power source into AC power applications. They are generally used in following applications:
Variable voltage/frequency AC supplies in adjustable speed drives...
