ABSTRACT
Voltage source inverters (VSI) are widely used in industrial applications and renewable energy systems. This chapter introduces some typical VSI circuits. Single-phase VSI can be implemented in half-bridge and full bridge circuits. Multistage pulse width modulation (PWM) inverters can be constructed by two methods: multicell and multilevel. Unipolar modulation PWM inverters can be considered multistage inverters. The carrier-based pulse width modulation technique is applied in this three-phase multistage PWM inverter. Multistage PWM inverters can consist of many cells. Each cell can be a single-phase or three-phase input plus single-phase output VSI. The chapter examines the single-phase source inverter operating in the bipolar modulation. Unipolar regulation method is likely a two-stage PWM inverter. If the output voltage is positive, only the upper device works and the lower device idles. The advantages to implement unipolar regulation are no need to set dead time and the pulses are narrow.
