Power conversion device and method of controlling power conversion device

A power conversion device comprising:

• a power conversion circuit including first and second switching elements connected in series between first and second lines;
• and
• a control circuit to control on/off of the first and second switching elements by hysteresis control based on a comparison of a detection value of an electrical quantity treated in power conversion by the power conversion circuit with an upper limit and a lower limit of a hysteresis band encompassing a command value of the electrical quantity,
• wherein the on/off of the first and second switching elements is controlled such that a dead time is provided in which both of the first and second switching elements are turned off when the on/off is switched,
• the control circuit including
• a hysteresis band generation unit to generate a hysteresis bandwidth in the hysteresis control, in accordance with a target value of switching frequency of the first and second switching elements,
• an upper/lower limit setting unit to set the upper limit and the lower limit in accordance with the hysteresis bandwidth and the command value,
• a dead time compensation unit to add, to the upper limit and the lower limit set by the upper/lower limit setting unit, a compensation amount for preventing the detection value from falling outside the hysteresis band during the dead time,
• a hysteresis comparator to compare the detection value with the upper limit and the lower limit after processing by the dead time compensation unit, and
• a dead time generator to generate a control signal for the on/off of the first and second switching elements such that the dead time is given, based on an output signal of the hysteresis comparator,
• wherein the dead time compensation unit performs a process of adding the compensation amount with a different polarity to a different one of the upper limit and the lower limit between when the detection value is positive and when the detection value is negative.