Ground insulation impedance detection method, circuit and equipment with circuit

Abstract

The embodiment of the invention discloses a ground insulation impedance detection method, a circuit and equipment with the circuit. The circuit consists of a first voltage division circuit and a second voltage division circuit, wherein the first voltage division circuit is connected between a first output terminal and a ground wire; and the second voltage division circuit is connected between a second output terminal and the ground wire. The ground insulation impedance detection method comprises the following steps: enabling the resistance ratio of the first voltage division circuit and the second voltage division circuit to be changed from N to 1/N to N; respectively acquiring voltages at two ends of the first voltage division circuit and the second voltage division circuit under three circuit states; obtaining a first equation, a second equation and a third equation with the detected ground insulation impedance as an independent variable according to a series connection voltage division principle; respectively solving to obtain ground insulation impedance values of the first output terminal and the second output terminal by the simultaneous equations of the first equation, the second equation, and the third equation; and taking a minimum value as the detection result. The equipment with the circuit comprises a junction box and an inverter. According to the ground insulation impedance detection method provided by the invention, the detection accuracy of ground insulation impedance is improved and the problem that the detection result of a traditional detection scheme is inaccurate is solved.

Description

technical field [0001] The invention relates to a method and a circuit for detecting the insulation resistance of a DC power supply to ground. Background technique [0002] The DC power supply (such as electric vehicle power battery, photovoltaic array, etc.) has poor insulation resistance to the ground or the resistance value is lower than the specified value of the safety regulations, which will cause the DC power supply to form a high voltage to the ground, and then cause the shell of the equipment using the DC power supply to be charged. Not only is the equipment easily damaged, but it also poses a huge threat to personal safety. Therefore, it is necessary to detect the insulation resistance of the DC power supply to the ground, so as to take corresponding adjustment measures in time to ensure that the insulation resistance always meets the safety requirements. [0003] The existing insulation resistance detection scheme obtains the positive pole-to-ground insulation re...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention provides a method for detecting insulation resistance to ground, a circuit and equipment with the circuit, so as to solve the problem of inaccurate detection results of existing detection schemes

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