Research Projects

Power electronic inverter is widely used in electric drives. Essentially, in a typical application, for example driving ac machines, dc power is converted to ac power to drive the ac machine using the inverter. In the inverter, the dc power is continuously switched in a programmed manner to generate alternating power. Each switching cycle takes the inverter through a predetermined set of discrete stages to emulate the three phase ac power to drive the ac machine. The discrete stages correspond to distinct states of the inverter and transition continuously happens from one state to another. Usually in the analysis of inverter, its average continuous performance is analyzed. But in reality, the inverter and the machine are put through discrete states corresponding to the applied voltage emulating the application of continuous power. To get a realistic model, the inverter is to be considered a discrete event system (DES). DES is a discrete-state event-driven system. In a variation of DES, called hybrid system, each distinct state of DES corresponds to a dynamic system attached to it. This is precisely the model in which an electric drive using an inverter is to be described. In other words, an inverter can be described by DES. An electric drive driving an ac machine, for example, can be considered an hybrid system.