Abstract: A photovoltaic inverter system and a method, and a PID effect compensation device for the photovoltaic inverter system are provided. A processing control unit records operation conditions of photovoltaic modules, determines whether a PID effect compensation condition is met, calculates a compensation voltage optimally and controls the integrated PID compensation device to perform PID effect compensation on the photovoltaic modules.

Abstract: A method and a device for suppressing a common-mode voltage of an inverter AC cable relative to ground are provided. A control unit generates a control signal according to a voltage of the AC side of the inverter. A switch unit connects or disconnects the discharge unit with ground or reference ground in response to the control signal. A discharge unit discharges the common-mode voltage of the inverter AC cable relative to ground when the switch unit is turned on. Therefore, during maintenance of the inverter when the AC switch is turned off, the common-mode voltage of the AC cable relative to ground can be discharged without using the isolated sampling solution in the conventional technology which has a high implementation cost and has a high requirement on the insulation class of the components, thereby avoiding the risk of electric shock to the maintenance technician.

Abstract: A grid-connected single-stage photovoltaic inverter is provided, which includes a direct current (DC) to alternating current (AC) inverter circuit, a DC to DC voltage booster circuit and a bypass element. An output of the DC to AC inverter circuit is connected to an alternating current grid, the DC to DC voltage booster circuit is connected in series between a photovoltaic array and the DC to AC inverter circuit, and the bypass element is connected in parallel with the DC to DC voltage booster circuit. A rated power capacity of the DC to DC voltage booster circuit is less than a rated power capacity of the DC to AC inverter circuit.