Abstract: This application provides a power supply system and a conversion method. The power supply system includes a power generation apparatus, a converter circuit, and a drive control circuit. The drive control circuit may be configured to: when a power grid fails, control, based on duration of previous low voltage ride-through, the converter circuit to increase a value of a current to be output to the power grid from a first operating current value to a low voltage ride-through current value, to increase a voltage value at an output end of the converter circuit. Herein, the previous low voltage ride-through is latest low voltage ride-through. In this application, the system can control, based on duration of previous voltage ride-through, a current to be output by the converter circuit to the power grid, to reduce circuit oscillation, with a simple structure, a simple control method, and high safety.

Abstract: A power conversion apparatus and a control method for a power conversion apparatus to reduce an amplitude of an output voltage of a converter when a grid is recovered from a fault, to ensure device safety. The power conversion apparatus includes a controller and a converter, and the controller is connected to the converter. The controller is configured to: after the output voltage of the converter is less than a first threshold, when the output voltage of the converter rises to be greater than a second threshold, reduce an active current output by the converter to a first current value, and reduce a reactive current output by the converter to a second current value, where the second threshold is greater than the first threshold.

Abstract: An islanding detection method and apparatus for an inverter, and a power supply system to resolve a problem that an existing voltage total harmonic distortion (THD)-based islanding detection method has low islanding detection reliability due to existence of a relatively large detection dead zone. According to this detection method, the voltage total harmonic distortion changes more significantly before and after the islanding effect of the inverter occurs in order to reduce an islanding detection dead zone and improve islanding detection reliability.

Abstract: An islanding detection method and apparatus for an inverter, and a power supply system to resolve a problem that an existing voltage total harmonic distortion (THD)-based islanding detection method has low islanding detection reliability due to existence of a relatively large detection dead zone. According to this detection method, the voltage total harmonic distortion changes more significantly before and after the islanding effect of the inverter occurs in order to reduce an islanding detection dead zone and improve islanding detection reliability.