Patent ID: 9716455
Date: 2017-07-25
CPC Classifications: H02P

Claim:
1. A power conversion device, comprising: a power conversion section including a plurality of bridge-connected semiconductor switching elements arranged in an upper arm and a lower arm for each of a plurality of phases, and including direct current voltage terminals and alternating current voltage terminals, the switching elements converting direct current power to output alternating current power when turned on and off; a plurality of free wheel diodes, one of the free wheel diodes being connected in reverse parallel with each semiconductor switching element in the power conversion section; and a rotating electric machine connected to the alternating current voltage terminals of the power conversion section, a capacitor connected between the direct current voltage terminals of the power conversion section, wherein when a voltage across the direct current voltage terminals is below a specified value when starting the rotating electric machine, a speed of the rotating electric machine is detected in a condition where the voltage across the direct current voltage terminals is boosted to at least the specified value by intermittently turning on and off at least one of the plurality of semiconductor switching elements, wherein boosting the voltage across the direct current voltage terminals to at least the specified value is carried out by simultaneously and intermittently turning on and off all the semiconductor switching elements in either the upper arms or the lower arms of the power conversion section.