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.

The present disclosure provides a rapid shutdown device for a photovoltaic system, which is connected between a photovoltaic power generation module and a photovoltaic inverter and comprises an input port and an output port. The rapid shutdown device further comprises: a first switch and a second switch; a third switch and a fourth switch; a controller coupled to control terminals of the first switch, the third switch, and the fourth switch, and configured to control on and off of the first switch, the third switch, and the fourth switch, so that the rapid shutdown device operates in a normal state, a bypass state or a shutdown state.

The present disclosure provides a rapid shutdown device for a photovoltaic system, which is connected between a photovoltaic power generation module and a photovoltaic inverter and comprises an input port and an output port. The rapid shutdown device further comprises: a first switch and a second switch; a third switch and a fourth switch; a controller coupled to control terminals of the first switch, the third switch, and the fourth switch, and configured to control on and off of the first switch, the third switch, and the fourth switch, so that the rapid shutdown device operates in a normal state, a bypass state or a shutdown state.

A PV-optimiser power system for a photovoltaic installation for supply of power from a photovoltaic installation. The system includes a first DC/DC converter connected to a PV panel and to one or more energy storage modules, and a second DC/DC converter, connected in parallel to the PV panel in a string of PV panels of a PV installation, wherein the second DC/DC converter is configured to operate as an optimiser and execute a maximum power point tracking algorithm (MPPT) to determine the maximum power output of the PV panel of the plurality of the PV panels in the string.

A distributed energy conversion system may include one or more DC power sources and two or more inverters to convert DC power from the power sources to AC power. The AC power from the two or more inverters may be combined to provide a single AC output. A module may include one or more photovoltaic cells and two or more inverters. An integrated circuit may include power electronics to convert DC input power to AC output power and processing circuitry to control the power electronics. The AC output power may be synchronized with an AC power distribution system.

A distributed energy conversion system may include one or more DC power sources and two or more inverters to convert DC power from the power sources to AC power. The AC power from the two or more inverters may be combined to provide a single AC output. A module may include one or more photovoltaic cells and two or more inverters. An integrated circuit may include power electronics to convert DC input power to AC output power and processing circuitry to control the power electronics. The AC output power may be synchronized with an AC power distribution system.

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.

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.

A photovoltaic system includes an inverter and a plurality of photovoltaic units connected to the inverter. Each photovoltaic unit includes a controller and one or more photovoltaic modules connected to the controller. The controller in each photovoltaic unit is further configured to obtain a power carrier signal sent by a controller in another photovoltaic unit of the plurality of photovoltaic units, determine an attenuation reference factor of the power carrier signal based on the obtained power carrier signal, and send the attenuation reference factor to the inverter. The inverter is further configured to group the plurality of photovoltaic units based on the attenuation degree of the power carrier signal obtained by each photovoltaic unit. This application can implement automatic grouping of photovoltaic units.

A photovoltaic system includes an inverter and a plurality of photovoltaic units connected to the inverter. Each photovoltaic unit includes a controller and one or more photovoltaic modules connected to the controller. The controller in each photovoltaic unit is further configured to obtain a power carrier signal sent by a controller in another photovoltaic unit of the plurality of photovoltaic units, determine an attenuation reference factor of the power carrier signal based on the obtained power carrier signal, and send the attenuation reference factor to the inverter. The inverter is further configured to group the plurality of photovoltaic units based on the attenuation degree of the power carrier signal obtained by each photovoltaic unit. This application can implement automatic grouping of photovoltaic units.