Inverter apparatus and solar power generation system
An inverter apparatus comprising a first switch group that is connected to a DC power source and includes a first switch and a second switch connected in series; a capacitor that has one end thereof connected to a first connection point between the first switch and the second switch; a second switch group that is connected in parallel with the capacitor and includes a third switch and a fourth switch that are connected in series; a switch control section that controls an ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to convert DC voltage from the DC power source into AC voltage and output the AC voltage from a second connection point between the third switch and the fourth switch; and a smoothing circuit that is connected to the second connection point and normalizes a pulse waveform of the AC voltage.
1. An inverter apparatus comprising:
a first switch group that is connected to a DC power source and includes a first switch and a second switch connected in series;
a capacitor that has one end thereof connected to a first connection point between the first switch and the second switch;
a second switch group that is connected in parallel with the capacitor and includes a third switch and a fourth switch that are connected in series;
a switch control section that controls an ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to convert DC voltage from the DC power source into AC voltage and output the AC voltage from a second connection point between the third switch and the fourth switch; and
a smoothing circuit that is connected to the second connection point and normalizes a pulse waveform of the AC voltage, wherein
after turning the first switch and the second switch ON and OFF in an alternating manner and turning the third switch and the fourth switch ON and OFF in an alternating manner, the switch control section turns the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays OFF and the second switch stays ON.
2. A solar power generation system comprising:
a solar cell; and
the inverter apparatus of claim 1 that converts DC voltage from the solar cell into AC voltage.
3. An inverter apparatus comprising:
a first switch group that is connected to a DC power source and includes a first switch and a second switch connected in series;
a capacitor that has one end thereof connected to a first connection point between the first switch and the second switch;
a second switch group that is connected in parallel with the capacitor and includes a third switch and a fourth switch that are connected in series;
a switch control section that controls an ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to convert DC voltage from the DC power source into AC voltage and output the AC voltage from a second connection point between the third switch and the fourth switch; and
a smoothing circuit that is connected to the second connection point and normalizes a pulse waveform of the AC voltage, wherein
the switch control section turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF, and turns the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays ON and the second switch stays OFF.
4. The inverter apparatus according to claim 3 , wherein
after turning the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays ON and the second switch stays OFF, the switch control section turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF.
5. The inverter apparatus according to claim 4 , wherein
after turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF, the switch control section turns the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays OFF and the second switch stays ON.
6. The inverter apparatus according to claim 3 , further comprising a voltage measuring section that measures voltage of a system power source connected on the output side of the smoothing circuit, wherein
the switch control section determines a timing for switching from an operation of turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF to an operation of turning the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays ON and the second switch stays OFF, based on the voltage of the system power source.
7. A solar power generation system comprising:
a solar cell; and
the inverter apparatus of claim 3 that converts DC voltage from the solar cell into AC voltage.
8. An inverter apparatus comprising:
a first switch group that is connected to a DC power source and includes a first switch and a second switch connected in series;
a capacitor that has one end thereof connected to a first connection point between the first switch and the second switch;
a second switch group that is connected in parallel with the capacitor and includes a third switch and a fourth switch that are connected in series;
a switch control section that controls an ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to convert DC voltage from the DC power source into AC voltage and output the AC voltage from a second connection point between the third switch and the fourth switch; and
a smoothing circuit that is connected to the second connection point and normalizes a pulse waveform of the AC voltage, wherein
the inverter apparatus is connected to a three-phase AC power source, and
the switch control section controls the ON/OFF state of the first switch, the second switch, the third switch, and the fourth switch to output from the smoothing circuit shifted AC voltage obtained by shifting a reference AC voltage, with which the AC voltage is to be phase-synchronized, in a positive direction by a predetermined potential, from a reference potential of the reference AC voltage.
9. The inverter apparatus according to claim 8 , wherein
after turning the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays OFF and the second switch stays ON, the switch control section turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF.
10. The inverter apparatus according to claim 9 , wherein
after turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF, the switch control section turns ON the first switch, turns OFF the second switch, turns OFF the third switch, turns ON the fourth switch, and maintains the switches in this state.
11. The inverter apparatus according to claim 10 , wherein
if the state in which the first switch is ON, the second switch is OFF, the third switch is OFF, and the fourth switch is ON is maintained for an interval greater than 2π/3, the switch control section turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF and then, after turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays OFF and the fourth switch stays ON, turns ON the first switch, turns OFF the second switch, turns OFF the third switch, turns ON the fourth switch, and maintains the switches in this state.
12. The inverter apparatus according to claim 10 , wherein
after maintaining the state in which the first switch is ON, the second switch is OFF, the third switch is OFF, and the fourth switch is ON, the switch control section turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF.
13. The inverter apparatus according to claim 12 , wherein
if the state in which the first switch is ON, the second switch is OFF, the third switch is OFF, and the fourth switch is ON is maintained for an interval greater than 2π/3, the switch control section turns ON the first switch, turns OFF the second switch, turns OFF the third switch, turns ON the fourth switch, maintains the switches in this state and then, after turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays OFF and the fourth switch stays ON, turns the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF.
14. The inverter apparatus according to claim 12 , wherein
after turning the first switch and the second switch ON and OFF in an alternating manner while the third switch stays ON and the fourth switch stays OFF, the switch control section turns the third switch and the fourth switch ON and OFF in an alternating manner while the first switch stays OFF and the second switch stays ON.
15. A solar power generation system comprising:
a solar cell; and
the inverter apparatus of claim 8 that converts DC voltage from the solar cell into AC voltage.