Off-grid phase splitter and inverter system

1. An off-grid phase splitter, comprising:

a first input port and a second input port separately connected to a power supply that provides a first voltage;

a first output port, a second output port, and a third output port, wherein the first output port and the second output port provide a second voltage, the second output port and the third output port provide a third voltage, and both the second voltage and the third voltage are less than the first voltage;

a first capacitor connected between the first output port and the second output port, and a second capacitor connected between the second output port and the third output port;

a first switch circuit and a second switch circuit connected in series to form a first node between the first input port and the second input port, wherein the first switch circuit and the second switch circuit are unidirectionally switched on in opposite directions;

an inductor is connected between the first node and the second output port, wherein the first switch circuit and the second switch circuit enable electricity on the first capacitor to be transferred to the second capacitor through the inductor, or vice versa; and

a driving control system to control, based on a voltage at both ends of the first capacitor and a voltage at both ends of the second capacitor, the first switch circuit and the second switch circuit to be unidirectionally switched on, wherein the driving control system comprises:

a collector, configured to collect the voltage at both ends of the first capacitor, the voltage at both ends of the second capacitor, and a current of the inductor;

a voltage regulator, configured to receive a difference between a voltage value of the voltage at both ends of the first capacitor and a voltage value of the voltage at both ends of the second capacitor, to obtain a first current; and

a current regulator, configured to receive a generated current and the current of the inductor to obtain a fourth voltage, wherein

the driving control system calculates, based on the fourth voltage and a larger one of the voltage at both ends of the first capacitor and the voltage at both ends of the second capacitor, a duty cycle used to control the first switch circuit and the second switch circuit.

2. The off-grid phase splitter according to claim 1 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is greater than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a positive value, the second switch circuit forms a conducted circuit in a third direction; and

when the first switch circuit forms a conducted circuit in a first direction, the first capacitor discharges to the inductor; or when the first switch circuit forms an open circuit in the first direction, the inductor charges the second capacitor in the third direction by using the second switch circuit.

3. The off-grid phase splitter according to claim 2 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is greater than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a negative value, the second switch circuit forms a conducted circuit in a fourth direction; and

when the first switch circuit forms a conducted circuit in a second direction, the first capacitor discharges to the inductor; or when the first switch circuit forms an open circuit in the second direction, the inductor charges the second capacitor in the fourth direction by using the second switch circuit.

4. The off-grid phase splitter according to claim 1 , wherein

when an absolute value voltage value of a voltage at both ends of the first capacitor is less than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a positive value, the first switch circuit forms a conducted circuit in a first direction; and

when the second switch circuit forms a conducted circuit in a third direction, the second capacitor discharges to the inductor; or when the second switch circuit forms an open circuit, the inductor charges the first capacitor in the first direction by using the first switch circuit.

5. The off-grid phase splitter according to claim 4 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is less than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a negative value, the first switch circuit forms a conducted circuit in a second direction; and

when the second switch circuit forms a conducted circuit in a fourth direction, the second capacitor discharges to the inductor; or when the second switch circuit forms an open circuit, the inductor charges the first capacitor in the second direction by using the first switch circuit.

6. The off-grid phase splitter according to claim 5 , wherein

the first direction and the second direction are opposite directions, the third direction and the fourth direction are opposite directions, a direction in which a current on the first switch circuit flows to the inductor along the first direction is the same as a direction in which a current on the second switch circuit flows to the inductor along the third direction.

7. The off-grid phase splitter according to claim 5 , wherein the first switch circuit comprises a first switch and a second switch, and the second switch circuit comprises a third switch and a fourth switch;

a first switch configured to enable the first switch circuit to form a conducted circuit or an open circuit in the first direction; and

a second switch configured to enable the first switch circuit to form a conducted circuit or an open circuit in the second direction.

8. The off-grid phase splitter according to claim 7 , wherein the first switch and the second switch are formed by MOS transistors.

9. The off-grid phase splitter according to claim 5 , wherein the second switch circuit comprises:

a third switch configured to enable the second switch circuit to form a conducted circuit or an open circuit in the third direction; and

a fourth switch configured to enable the second switch circuit to form a conducted circuit or an open circuit in the fourth direction.

10. The off-grid phase splitter according to claim 9 , wherein the third switch and the fourth switch are formed by MOS transistors.

11. The off-grid phase splitter according to claim 1 , wherein

the driving control system calculates, based on the fourth voltage and the larger one of the voltage at both ends of the first capacitor and the voltage at both ends of the second capacitor, a duty cycle used to control a first switch, a second switch, a third switch, and a fourth switch.

12. An off-grid phase splitting method, comprising:

providing a first input port and a second input port separately connected to a power supply that provides a first voltage;

providing a first output port, a second output port, and a third output port, wherein the first output port and the second output port provide a second voltage, wherein the second output port and the third output port provide a third voltage, and wherein both the second voltage and the third voltage are less than the first voltage;

controlling, based on a voltage difference between a voltage at both ends of a first capacitor and a voltage at both ends of a second capacitor, one of a first switch circuit and a second switch circuit to be switched on, so that one of the first capacitor and the second capacitor discharges to an inductor, wherein the first capacitor is connected between the first output port and the second output port, the second capacitor is connected between the second output port and the third output port, the first switch circuit and the second switch circuit are connected in series to form a first node between the first input port and the second input port, and the inductor is connected between the first node and the second output port;

controlling the other one of the first switch circuit and the second switch circuit to be switched on, so that the inductor charges the other one of the first capacitor and the second capacitor; and

controlling by a driving control system, based on the voltage at both ends of the first capacitor and the voltage at both ends of the second capacitor, the first switch circuit and the second switch circuit to be unidirectionally switched on, wherein the driving control system further performs operations:

collecting, by a collector of the driving control system, the voltage at both ends of the first capacitor, the voltage at both ends of the second capacitor, and a current of the inductor;

receiving, by a voltage regulator of the driving control system, a difference between a voltage value of the voltage at both ends of the first capacitor and a voltage value of the voltage at both ends of the second capacitor, to obtain a first current;

receiving, by a current regulator of the driving control system, a generated current and the current of the inductor to obtain a fourth voltage; and

calculating, based on the fourth voltage and a larger one of the voltage at both ends of the first capacitor and the voltage at both ends of the second capacitor, a duty cycle used to control the first switch circuit and the second switch circuit.

13. An inverter system, comprising:

an inverter, configured to convert a direct current signal into an alternating current signal; and

an off-grid phase splitter, including:

a first input port and a second input port separately connected to a power supply that provides a first voltage,

a first output port, a second output port, and a third output port, wherein the first output port and the second output port provide a second voltage, the second output port and the third output port provide a third voltage, and both the second voltage and the third voltage are less than the first voltage,

a first capacitor connected between the first output port and the second output port, and a second capacitor connected between the second output port and the third output port,

a first switch circuit and a second switch circuit connected in series to form a first node between the first input port and the second input port, wherein the first switch circuit and the second switch circuit are unidirectionally switched on in opposite directions,

an inductor is connected between the first node and the second output port, wherein the first switch circuit and the second switch circuit enable electricity on the first capacitor to be transferred to the second capacitor through the inductor, or vice versa, and

a driving control system to control, based on a voltage at both ends of the first capacitor and a voltage at both ends of the second capacitor, the first switch circuit and the second switch circuit to be unidirectionally switched on, wherein the driving control system comprises:

a collector, configured to collect the voltage at both ends of the first capacitor, the voltage at both ends of the second capacitor, and a current of the inductor;

a voltage regulator, configured to receive a difference between a voltage value of the voltage at both ends of the first capacitor and a voltage value of the voltage at both ends of the second capacitor, to obtain a first current; and

a current regulator, configured to receive a generated current and the current of the inductor to obtain a fourth voltage, wherein

the driving control system calculates, based on the fourth voltage and a larger one of the voltage at both ends of the first capacitor and the voltage at both ends of the second capacitor, a duty cycle used to control the first switch circuit and the second switch circuit.

14. The inverter system according to claim 13 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is greater than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a positive value, the second switch circuit forms a conducted circuit in a third direction; and

when the first switch circuit forms a conducted circuit in a first direction, the first capacitor discharges to the inductor; or when the first switch circuit forms an open circuit in the first direction, the inductor charges the second capacitor in the third direction by using the second switch circuit.

15. The inverter system according to claim 14 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is greater than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a negative value, the second switch circuit forms a conducted circuit in a fourth direction; and

when the first switch circuit forms a conducted circuit in a second direction, the first capacitor discharges to the inductor; or when the first switch circuit forms an open circuit in the second direction, the inductor charges the second capacitor in the fourth direction by using the second switch circuit.

16. The inverter system according to claim 13 , wherein

when an absolute value voltage value of a voltage at both ends of the first capacitor is less than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a positive value, the first switch circuit forms a conducted circuit in a first direction; and

when the second switch circuit forms a conducted circuit in a third direction, the second capacitor discharges to the inductor; or when the second switch circuit forms an open circuit, the inductor charges the first capacitor in the first direction by using the first switch circuit.

17. The inverter system according to claim 16 , wherein

when an absolute voltage value of a voltage at both ends of the first capacitor is less than an absolute voltage value of a voltage at both ends of the second capacitor, and a voltage value between the first output port and the third output port is a negative value, the first switch circuit forms a conducted circuit in a second direction; and

when the second switch circuit forms a conducted circuit in a fourth direction, the second capacitor discharges to the inductor; or when the second switch circuit forms an open circuit, the inductor charges the first capacitor in the second direction by using the first switch circuit.

18. The inverter system according to claim 17 , wherein, wherein

the first direction and the second direction are opposite directions, the third direction and the fourth direction are opposite directions, a direction in which a current on the first switch circuit flows to the inductor along the first direction is the same as a direction in which a current on the second switch circuit flows to the inductor along the third direction.