A controller for a power conversion circuit includes a first limiter for limiting a compensating voltage component within a compensating voltage switching level. A delay time measurement section measures an ON-delay time and an OFF-delay time, based on a binarized digital value and a PWM command value. A multiplier calculates an error voltage component average value by multiplying an average value of the ON-delay time and the OFF-delay time by a value that is obtained by dividing a direct-current power supply voltage by a half cycle of a triangular wave carrier signal. A second limiter extracts a component of the error voltage component average value that is beyond the compensating voltage switching level in absolute value. An adder sets a combined compensating voltage component to a sum of a limited compensating voltage component outputted by the first limiter and a limited error voltage component outputted by the second limiter.