The implementation of a DFC topology under scalar control algorithm with a voltage gain beyond unity

The implementation of a novel direct frequency changer topology is proposed. This converter is controlled using the scalar control algorithm. The performance of the scalar algorithm has already been demonstrated in a direct frequency changer using bidirectional switches in a unique matrix topology, The proposed converter is made of two units called semi-direct frequency changers (SDFC). Each unit has six unidirectional switches which are operated under the scalar control algorithm. The two units are connected by a DC link. It would seem this setup results in double conversion, but contrary to real intermediate conversion frequency changers, energy storage elements in the DC link are associated only with the commutation frequency, This converter improves the voltage transfer ratio by effectively removing the 0.87 limit normally imposed by direct conversion. A set of four standard microcontrollers is used to implement the control unit which also provides real-time operation. Finally, laboratory test results from a 100 W prototype are presented.