Non-isolated inverting apparatus, control method thereof and photovoltaic system having the same

A non-isolated inverting apparatus, comprising:

• a DC port comprising a first terminal and a second terminal;
• an AC port comprising a first terminal and a second terminal;
• five switches comprising a first switch, a second switch, a third switch, a fourth switch and a fifth switch, each of the switches having a first terminal, a second terminal and a third terminal,
• wherein the first terminal of the first switch and the first terminal of the fifth switch are electrically coupled to the first terminal of the DC port, the second terminal of the second switch and the first terminal of the fourth switch are electrically coupled to the second terminal of the DC port and the second terminal of the AC port, the first terminal of the third switch and the second terminal of the first switch are electrically coupled to the first terminal of the AC port, and the second terminal of the third switch is electrically coupled to the second terminal of the fourth switch;
• a first inductor electrically coupled between the first terminal of the second switch and the second terminal of the fifth switch;
• a first capacitor electrically coupled between the first terminal of the second switch and the second terminal of the fourth switch;
• and
• a free-wheeling element electrically coupled between the second terminal of the third switch and the second terminal of the fifth switch;
• wherein the five switches are configured to be controlled via the third terminal respectively, according to control signals, so that the inverting apparatus are switched among a plurality of operating modes and transmit an active power or a reactive power to a power grid, and that in at least one of the operating modes, only one switch connected between the AC port and the DC port is turned on.