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 linkage protection system includes an inverter, an anti-potential-induced degradation (PID) apparatus, and an insulation-monitoring apparatus. The anti-PID apparatus is configured to inject a voltage into an input end or an output end of the inverter, to increase or decrease a voltage-to-earth of a photovoltaic system. The insulation-monitoring apparatus is configured to inject an insulation-monitoring voltage into a direct current (DC) side or an alternating current (AC) side of the inverter. The anti-PID apparatus and the insulation-monitoring apparatus directly or indirectly communicate with each other, to learn of information about whether a peer apparatus is operating, and perform linkage control. The anti-PID apparatus and the insulation-monitoring apparatus operate in different time periods.

Abstract: Embodiments of this application disclose a control method for a photovoltaic power generation system and a photovoltaic power generation system, to reduce a photovoltaic energy loss. The method includes: presetting, by the photovoltaic power generation system, an upper limit value for each converter in the photovoltaic power generation system, where the upper limit value is a maximum voltage value of an output voltage to ground of the converter, and the output voltage to ground is a voltage difference between a positive output end of the converter and a ground point of the photovoltaic power generation system; and limiting, by the photovoltaic power generation system, an output voltage to ground of a target converter based on an upper limit value corresponding to the target converter, where the target converter may be any converter in the photovoltaic power generation system.

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: A method and an apparatus for detecting a short circuit of an inverter, and an inverter are provided. A voltage of a common bus is increased when a plurality of boost circuits in the inverter are all in a non-working state, and after circuit parameters of input sides of all the plurality of boost circuits are detected, a boost circuit in which a diode is short-circuited in the plurality of boost circuits is further determined based on the circuit parameters of the input sides of the boost circuits. According to the method and the apparatus for detecting a short circuit of an inverter, and the inverter, circuit complexity of the inverter can be reduced, and circuit complexity of a photovoltaic power generation system including the inverter is reduced.

Abstract: An inverter in a power generation system converts a direct current that is input from a direct-current-side device into an alternating current for power supply. The inverter includes a control apparatus and a communications apparatus. The control apparatus controls the inverter to convert the direct current that is input from the direct-current-side device into an alternating current for power supply. The communications apparatus is coupled to the control apparatus, and sends a networking information request signal used to request networking information to the direct-current-side device in the power generation system through a direct-current power line, where a frequency of the networking information request signal is within a first frequency band. The communications apparatus also receives the networking information from the direct-current-side device; and sends a control signal to the direct-current-side device, where a frequency of the control signal is within a second frequency band.

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 photovoltaic power generation system includes an inverter, a controller, and at least two direct current branch circuits. The leakage current detection apparatus is configured to: detect a leakage current of the direct current branch circuit on which the leakage current detection apparatus is located and send the leakage current to the controller. The controller is further configured to: when the photovoltaic power generation system runs and a value of a leakage current of the direct current branch circuit exceeds a preset range, determine that an insulation fault occurs on the direct current branch circuit. The system can determine the direct current branch circuit on which the insulation fault occurs in the photovoltaic power generation system, so that measures are taken in time for the direct current branch circuit on which the insulation fault occurs, to eliminate a potential safety hazard.

Abstract: A power system is disclosed. Output terminals of a power supply or a DC-to-DC unit are cascaded to increase an output voltage, so as to reduce a current between the power supply or the DC-to-DC unit and the DC-to-AC unit, and resolve cost and loss problems of the cable from the power supply or the DC-to-DC unit to the DC-to-AC unit. In addition, according to the power system provided in the 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 output terminals of the power supply or the DC-to-DC unit and cascading inputs of the DC-to-AC unit, thereby reducing system costs. In addition, in the power system provided in the embodiments of this application, cascaded input and isolated output of the DC-to-AC unit can reduce a specification of a power conversion device.

Abstract: This application discloses a method and an apparatus for detecting a solar cell of a photovoltaic plant. The method includes: obtaining a first infrared image and a second infrared image, where the first infrared image includes infrared image information corresponding to an ambient infrared signal reflected by a to-be-detected solar cell operating in a short-circuit state, the second infrared image includes infrared image information corresponding to an infrared signal emitted by the to-be-detected solar cell operating in a first state and infrared image information corresponding to an ambient infrared signal reflected by the to-be-detected solar cell, and the first state is another state other than the short-circuit state; and detecting, based on the first infrared image and the second infrared image, whether the to-be-detected solar cell has a defect.

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: This application discloses an inverter of a grid-connected photovoltaic power generation system. The inverter includes a grid-connected inverter unit, an alternating current auxiliary power supply, and a startup apparatus. The alternating current auxiliary power supply is configured to convert an alternating current from an alternating current power grid into a direct current. An input terminal of the grid-connected inverter unit is connected to a bus capacitor. The startup apparatus is configured to: obtain an alternating current from the alternating current power grid, convert the alternating current into a direct current, and then provide the direct current to the bus capacitor, to start the grid-connected inverter unit. By using the inverter, the grid-connected photovoltaic power generation system can be started normally when there is insufficient or no sunlight, to allow scheduling of the grid-connected photovoltaic power generation system to be normally performed.

Abstract: A fault detection apparatus includes an image capture module and a detection module, and the fault detection apparatus is configured to capturing an image of the photovoltaic module in a light emitting state, and performing fault detection on the photovoltaic module based on the image when a signal-to-noise ratio of the image is maximized, to identify a fault type of the photovoltaic module.

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: This application relates to the field of circuit technologies, and provides a step-up circuit and a step-up circuit control method. The step-up circuit includes a power supply, an inductor, N switch components, N-1 flying capacitors, N flyback diodes, a pre-charge unit, and an output unit. The N switch components are connected in series, a first switch component of the N switch components is connected to a first terminal of the power supply through the inductor, and an Nth switch component is connected to a second terminal of the power supply. At least two switch components of the N switch components have withstand voltage specifications different from each other. Values of voltages withstood by switch components with different withstand voltage specifications during normal operation are also different from each other. N is a positive integer.

Abstract: A breaker apparatus and an inverter system are configured to disconnect an electrical connection when a fault occurs in a protected circuit. The breaker apparatus is connected in series in a protected circuit, and is configured to disconnect the electrical connection when a fault occurs in the protected circuit. The breaker apparatus includes a first branch, and a second branch. The first branch includes an overcurrent-automatic-disconnection unit and a first current limiting unit that are connected in series, where the overcurrent-automatic-disconnection unit is configured to be automatically disconnected when a current flowing through the overcurrent-automatic-disconnection unit exceeds a breaking current threshold. The a second branch is configured to be open or closed under control of the controller.

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 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: 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: A power supply system includes at least one inverter, at least one cell string, and a transformer, where an input end of the at least one inverter is connected to an output end of the at least one cell string, an output end of the at least one inverter is connected to an input end of the transformer, and an output end of the transformer is configured to output a power supply voltage. The output end of the at least one inverter is connected to an output end of an inverter unit.