Patent ID: 8773082
Filing Date: 2014-07-08
Classification: H02M

Abstract:
1. A DC/DC power conversion apparatus comprising: high voltage terminals; low voltage terminals; a device series unit including a plurality of rectification devices connected in series to each other, the device series unit being connected between the high voltage terminals; switching devices connected in parallel to all or some of the plurality of rectification devices, respectively; at least one capacitor for retaining a divided voltage of a voltage between the high voltage terminals, the at least one capacitor being connected in parallel to the plurality of the rectification devices; a reactor for, in accordance with switching operation of the switching devices, allowing conduction and performing operation to store or release energy, one end of the reactor being connected to one of the low voltage terminals, and the other end being connected to a series connection point among the plurality of rectification devices; and a control circuit for, by controlling ON/OFF operation of the switching devices, controlling DC voltage conversion between the voltage between the high voltage terminals and a voltage between the low voltage terminals, wherein with the voltage ratio k being the voltage between the high voltage terminals divided by the voltage between the low voltage terminals, the range of the voltage ratio k for executing the DC voltage conversion is divided into a plurality of operation regions and the plurality of operation regions include an operation region including the voltage ratio k=2; and wherein the control circuit sets, in accordance with the operation regions of the DC voltage conversion, a switching frequency at which the switching devices perform ON/OFF operation, such that the magnitude of a current ripple flowing in the reactor is equal to or smaller than a predetermined limiting value irrespective of the operation regions and the switching frequency set for the operation region including k=2 is equal to or lower than the switching frequencies set for the other operation regions.