Patent ID: 9197135
Filing Date: 2015-11-24
Classification: H02M,Y02B

Abstract:
1. A bi-directional DC/DC converter capable of bi-directional power supply between a first DC voltage source and a second DC voltage source through an isolation transformer, the bi-directional DC/DC converter comprising: a first bridge circuit composed of a plurality of semiconductor switching elements connected to the first DC voltage source; a second bridge circuit composed of a plurality of semiconductor switching elements connected to the second DC voltage source; the isolation transformer connected between an AC side of the first bridge circuit and an AC side of the second bridge circuit; an LC resonance circuit composed of at least one set of a reactor and a capacitor connected between the AC side of the first bridge circuit and the isolation transformer or a reactor and a capacitor connected between the AC side of the second bridge circuit and the isolation transformer; a first detection circuit for detecting a voltage and a current of the first DC voltage source; a second detection circuit for detecting a voltage and a current of the second DC voltage source; a first control circuit for controlling the semiconductor switching elements of the first bridge circuit; and a second control circuit for controlling the semiconductor switching elements of the second bridge circuit; wherein the first control circuit has a control means for performing fixed frequency control of the semiconductor switching elements of the first bridge circuit at around a resonance frequency of the LC resonance circuit, and a control means for performing frequency modulation control of the semiconductor switching elements of the first bridge circuit at a frequency lower than the resonance frequency; the second control circuit has a control means for performing fixed frequency control of the semiconductor switching elements of the second bridge circuit at around the resonance frequency of the LC resonance circuit, and a control means for performing frequency modulation control of the semiconductor switching elements of the second bridge circuit at a frequency lower than the resonance frequency; the first control circuit also has a first change-over means for performing change-over of the first bridge circuit between the fixed frequency control and the frequency modulation control based on a magnitude of a control variable determined according to detected values by the second detection circuit in a mode of supplying electric power from the first DC voltage source to the second DC voltage source; the second control circuit also has a second change-over means for performing change-over of the second bridge circuit between the fixed frequency control and the frequency modulation control based on a magnitude of a control variable determined according to detected values by the first detection circuit in a mode of supplying electric power from the second DC voltage source to the first DC voltage source.