The two major types of drives are known as voltage source inverter (VSI) and current source inverter (CSI). In industrial markets, the VSI design has proven to be more efficient, have higher reliability and faster dynamic response, and be capable of running motors. A current-source inverter is a type of inverter used to control a motor. Its main function is to control the motor's speed, torque, and operating status by adjusting the output current of the control circuit. A current-source inverter ty pic ally consists of a DC power supply, an inverter, a. There are two types of fixed-frequency pulse-width modulation (PWM) control: voltage mode (VM) and current mode (CM). Figure 1 shows a diagram that explains both control types. The PWM inverter can switch on and off the IGBT at much faster rate. Thus, it is possible to get almost perfect sinusoidal voltage, with a very low harmonic distortion.