An integrated high power factor three-phase AC-DC-AC converter for AC-machines implemented in one microcontroller

A high power factor three-phase AC-DC-AC power converter for AC machines has been designed and tested. The AC-DC-AC converter is controlled by one single 16-b microcontroller. The converter has two PWM-VSI bridges with common snubber- and drive-circuit topologies. The high power factor rectifier is space vector controlled and the inverter controls an AC-induction machine by an energy optimized strategy. Common software tasks are utilized in order to minimize memory demands in the microcontroller. Measurements show a high power factor of the converter, and, in addition, the converter can very rapidly change from motor to generator operation during reversing of the AC machine. It is concluded that the AC-DC-AC converter works well, can be designed to be very compact, and represents some of the state-of-the-art integration and performance in three-phase AC-DC-AC converters