DC/DC voltage converter and voltage conversion control method therefor

A voltage conversion control method for a DC/DC voltage converter, the DC/DC voltage converter being configured to control voltage conversion of a converter main circuit with use of a control unit,

• the converter main circuit comprising:
• a first smoothing capacitor and a second smoothing capacitor for voltage smoothing, the first smoothing capacitor being connected between a positive terminal and a negative terminal on a primary side of the converter main circuit, the second smoothing capacitor being connected between a positive terminal and a negative terminal on a secondary side of the converter main circuit;
• a power module comprising at least two pairs of two power semiconductor units, each of which comprises a switch element and a rectifier element that are connected in anti-parallel,
• one of the two power semiconductor units in one of the at least two pairs and one of the two power semiconductor units in another one of the at least two pairs being connected in series between the positive terminal on the primary side and the positive terminal on the secondary side,
• another of the two power semiconductor units in the one of the at least two pairs and another of the two power semiconductor units in the another one of the at least two pairs being connected in series between the positive terminal on the primary side and the negative terminal on the secondary side in a direction reverse to a direction of the ones of the two power semiconductor units;
• an energy transfer capacitor connected between a secondary-side terminal of one of the two power semiconductor units and a secondary-side terminal of another of the two power semiconductor units in the one of the at least two pairs excluding a pair of power semiconductor units closest to the secondary side;
• and
• an inductor connected between a pair of the power semiconductor units closest to the primary side and the positive terminal on the primary side,
• the voltage conversion control method comprising performing control by switching a plurality of switch-ON circuits having different resistance values so as to increase a rate of charging electric charge of a gate capacitance of the switch element of each of the at least two pairs of two power semiconductor units when a conduction current of the inductor remains in any one of a positive polarity and a negative polarity in an operation of the converter main circuit.