Patent ID: 7126832

Claim:
A control unit of an electric power conversion apparatus comprising: a converter section having semiconductor switches forming a bridge configuration, for converting AC power of an AC power supply into DC power; a smoothing capacitor for smoothing the DC power converted by the converter section; a DC voltage control section for performing discrete system control of DC voltage so that the DC voltage of the smoothing capacitor matches a DC voltage command value; a reference sine wave generation section based on discrete system control for outputting a sine wave signal used as reference based on AC voltage of the above-mentioned AC power supply; an AC command value calculation section based on discrete system control for multiplying output of the DC voltage control section by output of the reference sine wave generation section and outputting an AC command value; an AC control section for calculating an AC voltage command value based on the AC command value output from the AC command value calculation section and AC of the AC power supply and outputting the AC voltage command value; a pulse width modulation section inputted the AC voltage command value, for generating an on/off signal for turning on/off the semiconductor switch based on continuous control; and a switch drive section for turning on/off the semiconductor switch in accordance with the on/off signal output from the pulse width modulation section, wherein the AC control section includes: a band-pass filter with a power supply frequency as the center frequency and set to a gain not exceeding 1 with the power supply frequency as the center band, the band-pass filter inputted the AC command value output from the AC command value calculation section; a subtraction section for calculating deviation between a signal passing through the band-pass filter, of the AC command value and the AC of the AC power supply; and a proportional calculation section for inputting the deviation calculated by the subtraction section and calculating an AC voltage command value reducing the deviation to zero by proportional calculation; and wherein the AC control section calculates the AC voltage command value based on continuous control.