Power transfer system

摘要

A power-transmission-unit-side resonant circuit includes a resonant capacitor connected in series with a power transmission coil and a power-reception-unit-side resonant circuit including a resonant capacitor connected in series with a power reception coil resonate with each other to cause sympathetic vibration. This allows power to be transferred using two kinds of coupling via the magnetic field and the electric field between the power transmission coil and the power reception coil. Also, operation is performed at a switching frequency that is higher than a specific resonant frequency of the entire multi-resonant circuit, such that a ZVS operation is performed. As a result, a switching loss is reduced by a large amount and a highly efficient operation is performed thus enabling a power transfer system with a reduced size and an increased power conversion efficiency to be provided.

主权项

1. A power transfer system comprising:
a power transmission unit including a power transmission coil; and a power reception unit including a power reception coil; wherein
the power transmission unit includes:a power-transmission-unit-side resonant capacitor that constitutes a power-transmission-unit-side resonant circuit together with the power transmission coil; anda power-transmission-unit-side alternating-current voltage generation circuit that is connected to the power transmission coil, that includes a switching circuit, and that generates an alternating-current voltage from a direct-current voltage input thereto, the switching circuit being a parallel circuit in which a switching element, a diode, and a capacitor are connected in parallel with each other; the power reception unit includes:
a power-reception-unit-side resonant capacitor that constitutes a power-reception-unit-side resonant circuit together with the power reception coil; anda power-reception-unit-side rectifier circuit that is connected to the power reception coil and that rectifies an alternating-current voltage produced in the power reception coil into a direct-current voltage; wherein mutual inductance and mutual capacitance that are equivalently generated between the power transmission coil and the power reception coil constitute an electromagnetic coupling circuit, the power-transmission-unit-side resonant circuit and the power-reception-unit-side resonant circuit resonate with each other, and power is transferred from the power transmission unit to the power reception unit; energy of power that has not been transmitted from the power transmission unit is retained in the power-transmission-unit-side resonant circuit as resonance energy; and energy that has not been supplied to an output among energy of power received by the power reception unit is retained in the power-reception-unit-side resonant circuit as resonance energy.