Patent ID: 7688018
Filing Date: 2010-03-30
Classification: H02P

Abstract:
1. An inverter comprising: an inverter circuit having upper-arm switching elements connected on a positive side of a DC power source and lower-arm switching elements connected on a negative side of the DC power source; a current sensor for detecting current flowing between the DC power source and the inverter circuit; and a control circuit energizing the inverter circuit by a PWM system for the inverter circuit to supply an AC to a motor, and detecting a phase current with the current sensor through a correction of a time, during which an ON-signal is supplied to only one or only two of the upper-arm switching elements, into a predetermined time necessary for detecting the phase current by the current sensor within a carrier cycle; wherein, the control circuit judges a direction of current, which is a direction flowing into the motor or a direction flowing out of the motor, of a phase having an intermediate length of an ON-period in the carrier cycle and changes the predetermined time according to the direction.