Power converter

A power converter that performs direct-current (DC) voltage conversion, the power converter comprising:

• a first bridge including a plurality of first legs;
• a second bridge including a plurality of second legs;
• a transformer connected between the first bridge and the second bridge;
• each of the first legs including a switching element on a high voltage side and a switching element on a low voltage side connected in series between a first power line on the high voltage side and a second power line on the low voltage side with an intermediate node in between,
• each of the second legs including a switching element on the high voltage side and a switching element on the low voltage side connected in series between a third power line on the high voltage side and a fourth power line on the low voltage side with an intermediate node in between,
• the transformer including
• a primary winding connected to a plurality of the intermediate nodes of the first legs, and
• a secondary winding connected to a plurality of the intermediate nodes of the second legs and magnetically coupled to the primary winding,
• the power converter comprising:
• a plurality of reactors respectively connected between a chargeable DC power supply and the intermediate nodes of the first legs;
• and
• a control circuit to control ON and OFF of a plurality of the switching elements of each of the first legs and the second legs, wherein
• the control circuit controls, in the first bridge, according to a first control command value for controlling a first DC voltage between the first power line and the second power line, ON and OFF of respective switching cycles of the switching elements of the first legs so as to
• provide an ON period of one switching element of the switching element on the high voltage side and the switching element on the low voltage side of each of the first legs for increasing an absolute value of a reactor current flowing through each of the reactors, and
• provide an ON period of the other switching element of the switching element on the high voltage side and the switching element on the low voltage side until the absolute value of the reactor current returns to zero after end of the ON period of the one switching element, and
• the control circuit controls, in the second bridge, ON and OFF of respective switching cycles of the switching elements of the second legs so as to
• reflect a second control command value for controlling a second DC voltage between the third power line and the fourth power line, and
• cause an ON period length of the switching element on the high voltage side of each of the second legs is substantially equal to an ON period length of the switching element on the high voltage side of each of the first legs, and an ON period length of the switching element on the low voltage side of each of the second legs is substantially equal to an ON period length of the switching element on the low voltage side of each of the first legs.