Source: {"pile_set_name": "USPTO Backgrounds"}

Conventionally, an inverter device for detecting current by current detecting device provided for a DC part in an inverter is known. In the case of detecting currents of respective phases by current detecting device provided for the DC part in the inverter, current has to be detected in an active voltage vector interval. Consequently, current detection cannot be performed at the peak of a PWM reference signal as a carrier signal, and a ripple component is included in a current detection value. To address the problem, for example, in Patent Literature 1, timings which are symmetrical with respect to the carrier peak are obtained, an average value is used as a phase current detection value at the carrier peak, and the average value is used as a current value at the carrier peak.
In Patent Literature 1, current has to be detected at timings which are symmetrical with respect to the carrier peak. Since sampling intervals vary according to the magnitude of voltage, the sampling intervals cannot be made constant. In addition, since the current detection is performed four times per PWM cycle, the frequency of the current detection is high. In the case where a zero-voltage vector period is long such as the case where application voltage is small or large, the current detection cannot be performed properly.    Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2010-88260