| This thesis proposes switching strategies for AC chopper converters which can implement the multiple steps switching technique and convert the AC energy to AC, directly. The switching process in this technique depends on the current direction in the load.;The main advantage of the technique is that the load will not be disconnected during switching events. Also, the semi-soft switching topology overcomes the switching problems in the AC chopper converters, without increasing the conduction losses of the devices. In addition, this topology does not require a dead-time, an attribute that is essential in the other topologies for ensuring that there is not a short circuit on the input source. In addition, during the dead-time in the traditional AC chopper, the load current is completely is connected from the power source and drains across the snubber circuits, including increased power losses and a bulky snubber circuit.;The advocated semi-soft switching topology achieves the multiple step switching and reduces the switching losses, as compared to the hard switching topology with dead-time.;A comprehensive analysis is performed including operating principles and all calculations of the currents and power losses. Finally, computer simulations of the applications are executed to validate the approach. |
