Abstract: An electric power supply system for driving an electric rotating machine has a generator supplied with driving power from an engine to generate alternating-current electric power and a matrix converter as an alternating-current to alternating-current direct converter supplied with the alternating-current electric power to output arbitrary alternating-current electric power. By driving a motor with the alternating-current electric power supplied from the matrix converter, only one time electric power conversion is carried out to provide high efficiency in the whole system. In addition, electric power loss can be reduced so as to enhance a motor output when the system is applied to a vehicle power supply system.

Abstract: Transformer driving coils 24 and 25 are added to a DC-DC converter composed of a DC power supply 1, semiconductor switching devices 91 and 92, a transformer 2, rectifiers 81 and 82, a filter capacitor 3, and others, in order to perform a self-oscillating operation. On the other hand, an output-voltage detection and control circuit 6 is used to provide control consisting of both frequency and pulse-width modulation, thus keeping the output voltage constant without the use of any expensive IC circuits or pulse transformers.

Abstract: Transformer driving coils 24 and 25 are addled to a DC-DC converter composed of a DC power supply 1, semiconductor switching devices 91 and 92, a transformer 2, rectifiers 81 and 82, a filter capacitor 3, and others, in order to perform a self-oscillating operation. On the other hand, an output-voltage detection and control circuit 6; is used to provide control consisting of both frequency an( pulse-width modulation, thus keeping the output voltage constant without the use of any expensive IC circuits or pulse transformers.