Abstract: A circuit for arc detection in a direct current and a microprocessor to resolve a problem of low accuracy of a detection result of an existing circuit for arc detection in a direct current, where the circuit includes a current sampling circuit, a first circuit, a second circuit, and a microprocessor. The current sampling circuit is configured to perform current sampling on the direct current, and output a current sampling signal of the direct current. The first circuit is configured to output a time domain signal including at least one pulse. The second circuit is configured to output a frequency domain signal of the current sampling signal after amplifying and filtering the current sampling signal. The microprocessor is configured to determine that an arc exists in the direct current when a counting result of the quantity of arc events meets a preset condition.

Abstract: This application provides a noise generation circuit, a self-checking circuit, an AFCI, and a photovoltaic power generation system. The noise generation circuit includes a power switch module, a noise generator, and a capacitor, where the noise generator is connected to both the power switch module and the capacitor; the power switch module is configured to control, according to a self-checking instruction, whether the noise generator generates a noise signal; and the capacitor is configured to filter out a direct current component in the noise signal when the noise generator generates the noise signal. According to the noise generation circuit, the self-checking circuit, the AFCI, and the photovoltaic power generation system that are provided in this application, no noise signal is generated in a non self-checking time, thereby ensuring normal working of the AFCI and the photovoltaic inverter.

Abstract: This application provides a noise generation circuit, a self-checking circuit, an AFCI, and a photovoltaic power generation system. The noise generation circuit includes a power switch module, a noise generator, and a capacitor, where the noise generator is connected to both the power switch module and the capacitor; the power switch module is configured to control, according to a self-checking instruction, whether the noise generator generates a noise signal; and the capacitor is configured to filter out a direct current component in the noise signal when the noise generator generates the noise signal. According to the noise generation circuit, the self-checking circuit, the AFCI, and the photovoltaic power generation system that are provided in this application, no noise signal is generated in a non self-checking time, thereby ensuring normal working of the AFCI and the photovoltaic inverter.

Abstract: A circuit for arc detection in a direct current and a microprocessor to resolve a problem of low accuracy of a detection result of an existing circuit for arc detection in a direct current, where the circuit includes a current sampling circuit, a first circuit, a second circuit, and a microprocessor. The current sampling circuit is configured to perform current sampling on the direct current, and output a current sampling signal of the direct current. The first circuit is configured to output a time domain signal including at least one pulse. The second circuit is configured to output a frequency domain signal of the current sampling signal after amplifying and filtering the current sampling signal. The microprocessor is configured to determine that an arc exists in the direct current when a counting result of the quantity of arc events meets a preset condition.