| 主权项 |
1. A DC/AC converter comprising: at least one module having a three winding single phase transformer using an annular core with a single turn (α) winding, a single turn (γ) winding and a single turn (γ) winding extending through the core and having an (sp) control switch connected to the (β) winding, an (sz) control switch connected to the (β) and (γ) windings and an (sm) control switch connected to the y winding; a DC source with an AC converter connected to the a winding providing an input voltage to the at least one module, said at least one module; and, a switch controller connected to and providing pulse width modulation (PWM) activation of the (sp) control switch, (sz) control switch and (sm) control switch of the at least one module for a controlled output voltage and output current at an output of the at least one module, the switch controller operating in a first quadrant wherein average output voltage is greater than zero and output current is greater than zero, a second quadrant wherein average output voltage is less than zero and output current is greater than zero, a third quadrant wherein average output voltage is less than zero and output current is less than zero, and a fourth quadrant wherein average output voltage is greater than zero and output current is less than zero, said switch controller for first quadrant and third quadrant operation firing the (sz) control switch coincident with a transition of the input voltage and for second quadrant and fourth quadrant operation, preferring the (sp) and (sm) control switches to lead a transition of the input voltage by at least a time required for a natural commutation and a margin period in the (sz) control switch. |
