Power converting device and power conditioner using the same

A power-converting device, comprising:

• a first conversion circuit electrically connected between a reference potential point and a first input point on a high potential side of a direct current power supply;
• a second conversion circuit electrically connected between the reference potential point and a second input point on a low potential side of the direct current power supply;
• and
• a voltage-regulating circuit configured to adjust a magnitude of an applied voltage to the first conversion circuit and the second conversion circuit, wherein
• the first conversion circuit includes
• first to fourth switching elements electrically connected in series with each other between the first input point and the reference potential point in an order of the first switching element, the second switching element, the third switching element, and the fourth switching element from the first input point, and
• a first capacitor electrically connected in parallel with a series circuit of the second switching element and the third switching element,
• the first conversion circuit switches a magnitude of a voltage generated between the reference potential point and a first output point between three stages which are zero, a first level, and a second level, the first output point being a connection point of the second switching element and the third switching element,
• the second conversion circuit includes
• fifth to eighth switching elements electrically connected in series with each other between the reference potential point and the second input point in an order of the fifth switching element, the sixth switching element, the seventh switching element, and the eighth switching element from the reference potential point, and
• a second capacitor electrically connected in parallel with a series circuit of the sixth switching element and the seventh switching element,
• the second conversion circuit switches a magnitude of a voltage generated between the reference potential point and a second output point between three stages which are zero, a third level, and a fourth level, the second output point being a connection point of the sixth switching element and the seventh switching element, and
• the voltage-regulating circuit is configured to increase the magnitude of the applied voltage over time during a start time period from a start of supplying power from the direct current power supply until the first capacitor and the second capacitor are charged to a specified voltage,
• the power-converting device further comprising:
• a third conversion circuit electrically connected between the first output point and the second output point, including first to fourth switches in a full bridge configuration, and configured to convert a voltage generated between the first output point and the second output point into an alternate current voltage and to output the alternate current voltage;
• and
• an inductor electrically connected between the third conversion circuit and at least one of the first output point and the second output point, wherein
• a series circuit of the first switch and the second switch and a series circuit of the third switch and the fourth switch are connected in parallel with each other between the first output point and the second output point, and
• the third conversion circuit is configured to keep at least one pair of a pair of the first and second switches and a pair of third and fourth switches in an on state during the start time period to form a current path including the inductor between the first output point and the second output point.