Abstract: A photovoltaic system and a leakage current control method for the photovoltaic system includes at least one photovoltaic module group, at least one photovoltaic inverter, a grounded metal frame, and a sampling control unit. The photovoltaic module group is mounted on the grounded metal frame. An output end of the photovoltaic module group is connected to an input end of the photovoltaic inverter, and an output end of the photovoltaic inverter is connected to a power grid. The sampling control unit is coupled to both the photovoltaic module group and the photovoltaic inverter and is configured to detect a current value of a leakage current formed by a common-mode voltage of the photovoltaic inverter on a parasitic capacitor. Herein, the parasitic capacitor exists between the photovoltaic module group and the grounded metal frame.

Abstract: An impedance detection method and a photovoltaic system are provided to help reduce complexity and costs of impedance detection. The method includes: sampling a voltage between a direct current bus and a protective earthing at each of a first time point and a second time point, to obtain a first voltage value and a second voltage value; sampling a leakage current on the direct current bus at each of the first time point and the second time point, to obtain a first current value and a second current value; and calculating an insulation impedance value of a combiner box based on a difference between the first voltage value and the second voltage value and a difference between the first current value and the second current value, to determine whether impedance of the combiner box is abnormal.

Abstract: An inverter apparatus is disclosed in this application, which includes a plurality of protection units and a plurality of inverter units. For any protection unit, when a voltage at an input terminal of the protection unit is greater than a voltage at an output terminal of the protection unit, a path between the input terminal and the output terminal of the protection unit is in a forward conducted state; when the voltage at the output terminal of the protection unit is greater than the voltage at the input terminal voltage of the protection unit, the path between the input terminal and the output terminal of the protection unit is in a reverse cut-off state; and when a control terminal of the protection unit receives a first trigger signal, the path between the input terminal and the output terminal of the protection unit is in a reverse conducted state.

Abstract: A direct current (DC)/DC conversion circuit includes an input end, a power circuit, and an output end, a bypass circuit that is a unidirectional conduction circuit, and a switch disposed between the input end and the power circuit, where the input end is configured to be coupled to an external power supply to receive power to the DC/DC conversion circuit. The bypass circuit is coupled between the input end and the power circuit, the bypass circuit is disposed between the switch and the power circuit, and the bypass circuit is coupled to the power circuit in parallel. The switch is configured to be closed when the input end is reversely coupled to the external power supply to enable a current from a positive electrode of the external power supply to flow back to a negative electrode of the external power supply through the bypass circuit and the switch.

Abstract: In a detection condition determining method, a control center obtains a working parameter value of a target photovoltaic device in a first time length closest to a current time point, where the working parameter value of the target photovoltaic device may be provided for the control center by a photovoltaic inverter coupled to the target photovoltaic device. The control center detects the target photovoltaic device in response to the control center determining, based on the working parameter value, that an environmental parameter value of the target photovoltaic device meets an environmental parameter threshold. Using the method helps reduce operation and maintenance costs of a photovoltaic power station.

Abstract: An example system includes an inverter and at least one combiner box. The combiner box includes a plurality of direct current-direct current (DC-DC) circuits and one controller. The controller is configured to: when an output voltage of the combiner box is greater than or equal to a first preset voltage and less than or equal to a second preset voltage, control the combiner box to output a maximum power. When the output voltage of the combiner box is greater than the second preset voltage, the controller controls an output power of the combiner box to decrease as the output voltage increases. The second preset voltage is greater than the first preset voltage, and the maximum power is a sum of maximum powers of all photovoltaic strings connected to the combiner box.

Abstract: A device for resolving common-mode voltage interference is applied to a power supply system including a power converter and a switch mechanism. Each phase of an output end of the power converter is connected to a downstream circuit by using the switch mechanism. The switch mechanism includes a first switch and a second switch. The device includes a controller and a passive component. Two ends of the first switch in at least one phase of the output end of the power converter are connected in parallel to the passive component, and the controller controls the second switch to be turned on, and when a voltage difference between the two ends of the first switch is less than a preset voltage, controls the first switch to be turned on. In this manner, the switch mechanism is protected, thereby prolonging a service life of the switch mechanism.

Abstract: A photovoltaic system includes a controller and two groups of inverters. The two groups of inverters include a positive inverter group and a negative inverter group. The positive inverter group includes at least two inverters: a first inverter and a third inverter. The negative inverter group includes at least two inverters: a second inverter and a fourth inverter. Alternating current output ends of the first inverter and the third inverter are connected in parallel. Direct current input ends of the first inverter and the second inverter are connected in series. Alternating current output ends of the second inverter and the fourth inverter are connected in parallel. Direct current input ends of the third inverter and the fourth inverter are connected in series.

Abstract: A photovoltaic system and a circulating current suppression method. The system includes a controller and at least two inverters. A direct current input terminal of each inverter is connected to a corresponding photovoltaic array. Alternating current output terminals of the at least two inverters are connected in parallel. The controller is configured to: obtain a direct current component of a common-mode output current of at least one of the at least two inverters and adjust a direct current bus voltage of the corresponding inverter based on a magnitude of the direct current component of the common-mode output current, to suppress a circulating current between the at least two inverters. A circulating current between a plurality of inverters connected in parallel can be suppressed, thereby reducing loss caused by a circulating current, and improving power supply efficiency.

Abstract: A fault detection apparatus includes a temperature detection unit, a current detection unit, a controller, and a breaking unit. The temperature detection unit is configured to detect temperatures of the plurality of filter capacitors and output the temperatures to the controller. The current detection unit is coupled to the plurality of filter capacitors and is configured to detect currents of the plurality of filter capacitors and output the currents to the controller. The controller is separately connected to the temperature detection unit, the current detection unit, and the breaking unit, and is configured to: when the received temperature exceeds a first threshold and the received current exceeds a second threshold, control the breaking unit to be disconnected. The breaking unit is connected between the output end of the grid-tied inverter and the plurality of filter capacitors and is configured to be disconnected or connected under control of the controller.

Abstract: A converter includes a power conversion circuit, a switching device, and a controller, and includes N phases, where N is 2 or 3. An input end of the power conversion circuit is connected to a direct current power supply, and the power conversion circuit converts a direct current output by the direct current power supply into an alternating current. The switching device includes at least the following two stages: a first-stage switching device and a second-stage switching device. The first-stage switching device and the second-stage switching device separately include N switches, and the N switches are connected in series to the N phases respectively. An output end of the power conversion circuit is connected to an alternating current power grid through the first-stage switching device and the second-stage switching device that are connected in series.

Abstract: A connector and an electronic device, to resolve a problem of poor mountability of the connector. The connector includes a housing, a conductive core, and a fastening structure. The housing has a channel that passes through a first end and a second end of the housing. The conductive core is disposed in the channel. A solder leg is disposed on one end of the conductive core, and the solder leg protrudes from the first end of the housing and is configured to be soldered to a circuit board. The fastening structure is configured to fasten the housing to a panel. The conductive core may be directly soldered to the circuit board, so that a connection effect between the conductive core and the circuit board can be improved, and mounting steps can be reduced.

Abstract: This application discloses a photovoltaic device, a photovoltaic inverter, a system, and a power limit control method. The device includes a DC-DC converter circuit, an inverter circuit, and a controller. An input end of the DC-DC converter circuit is connected to a photovoltaic array, and an output end of the DC-DC converter circuit is connected to an input end of the inverter circuit. The controller is configured to: receive a power scheduling instruction, where the power scheduling instruction carries a power reference value; and when the power reference value is less than a power at a maximum power point, reduce an input current of the DC-DC converter circuit; or when an input voltage of the DC-DC converter circuit is greater than or equal to a preset voltage, increase an input current of the DC-DC converter circuit until an output power of an inverter becomes consistent with the power reference value.

Abstract: A common mode current controller of an inverter includes switches and an impedance correction circuit. One end of the impedance correction circuit is grounded, and the other end is connected to one end of each of the switches. The other end of each of the switches is connected to one of a positive terminal and a negative terminal of a direct current busbar capacitor. When a midpoint-to-ground voltage of the direct current busbar capacitor exceeds a threshold range, the switches are closed to adjust impedance matching between a positive terminal-to-ground equivalent impedance of the direct current busbar capacitor and a negative terminal-to-ground equivalent impedance of the direct current busbar capacitor.

Abstract: Embodiments of this application provide a power conversion circuit, a power transmission system, and a photovoltaic device. The power conversion circuit includes: a first bridge arm, where the first bridge arm includes a first upper bridge arm and a first lower bridge arm; the first upper bridge arm includes a switching component connected between an input positive end and an output end; the first lower bridge arm includes a switching component connected between the output end and an input negative end; each of the switching components includes a switching transistor and a first diode anti-parallel connected to the switching transistor.

Abstract: An inverter, an inverter system, and a method. The inverter includes an inverter circuit and a controller. When at least one of the following conditions is met, the controller adjusts at least one of parameters including an operating frequency, operating voltage, and operating current of the inverter, to increase a loss of the inverter, where the at least one condition is as follows: an output power of the inverter circuit is lower than a preset power, output current of the inverter circuit is lower than a preset current, operating temperature of the inverter is lower than a preset temperature, or operating humidity of the inverter is higher than a preset humidity. When any one of the foregoing conditions is met, the inverter may increase the operating temperature of the inverter or reduce the operating humidity of the inverter by increasing the loss of the inverter, thereby ensuring inverter operation.

Abstract: This application provides a photovoltaic power generation system. The system includes at least one first photovoltaic module, a photovoltaic inverter, a first two-way DC/DC converter, and at least one first energy storage unit, and further includes at least one second photovoltaic module or at least one second energy storage unit. The photovoltaic inverter includes a DC/DC converter and a DC-AC inverter, where the DC/DC converter is electrically connected to the at least one first photovoltaic module, and the DC/DC converter is connected to the DC-AC inverter through a direct current bus. For the photovoltaic power generation system, photovoltaic arrays and energy storage devices can be configured flexibly to cope with peaks and troughs of power consumption.

Abstract: A fault protection apparatus includes a first diode, a first switch component, a control unit, a first port, a second port, a third port, a fourth port, and a fifth port. The first port is connected to a positive common direct current bus of the common direct current bus. The second port is connected to a negative common direct current bus of the common direct current bus. The third port is connected to a positive local bus of a branch on which the fault protection apparatus is located. The fourth port is connected to a negative local bus of the branch on which the fault protection apparatus is located. The first diode and the first switch component are connected to the power system through the first port, the second port, the third port, and the fourth port.

Abstract: A photovoltaic converter string is provided, to control, one of switching transistors in a buck/boost circuit of the photovoltaic converter to be conducted, wherein the switching transistors are connected in parallel to a bypass diode; and control the other switching transistors in the buck/boost circuit to be cut off. Therefore, an output voltage of the photovoltaic converter is applied to both ends of the non-conducted switching transistor in the switching transistors connected in parallel to the bypass diode, and after the output voltage of the photovoltaic converter reaches a breakdown voltage of the non-conducted switching transistor, an avalanche breakdown occurs on the non-conducted switching transistor, and a voltage of both ends of the bypass diode connected to a positive output end and a negative output end of the photovoltaic converter is clamped to be less than or equal to the breakdown voltage of the switching transistor.

Abstract: Embodiments of this application provide a power system. An output terminal of a power supply or a DC-to-DC unit is cascaded. In addition, according to the power system provided in embodiments of this application, a quantity of cables from the power supply or the DC-to-DC unit to the DC-to-AC unit may be further reduced by cascading an output terminal of the power supply or the DC-to-DC unit and cascading an input of the DC-to-AC unit.