Improved circuit of AC choppers for single-phase systems

In this paper, an improved circuit of AC choppers for single-phase systems are proposed and investigated. This new circuit employs a DC chopper modulated switch with a diode bridge rectifier and two switches to provide freewheeling path for the load current when the modulated switch is off. The attractive feature of this improved circuit is that, it uses only a single modulated switch. The improved circuit has many advantages compared with the conventional ac choppers such as simple design requirements, easy implementation, higher power capacity, fast dynamic response, high reliability, high power factor, low cost, low switching loss and consequently high efficiency. By digital simulation several characteristics are investigated.