Insulation impedance detection circuit and method for non-isolated photovoltaic inverter

Abstract

The invention discloses an insulation impedance detection circuit and method for a non-isolated photovoltaic inverter. The insulation impedance detection circuit used for the non-isolated photovoltaicinverter comprises an insulation impedance function module used for detecting insulation impedance of a photovoltaic assembly to the ground; the insulation impedance detection circuit also comprisesa first switch and a detection resistor, one end of the first switch is used for being electrically connected to the casing of the photovoltaic inverter, the other end of the first switch is electrically connected with one end of the detection resistor, and the other end of the detection resistor is used for being electrically connected to a power grid and is grounded through a neutral point of the power grid. The detection blind area existing when the casing is not grounded is solved.

Description

technical field [0001] The invention belongs to the field of photovoltaic inverters, and relates to an insulation resistance detection circuit and method for non-isolated photovoltaic inverters. Background technique [0002] Under the global background of energy shortage and environmental degradation, the use of new clean energy is particularly important. Solar energy is widely developed and applied due to its renewable and abundant resources. With the popularization of photovoltaic grid-connected power generation applications, the safety of photovoltaic grid-connected power generation systems has received more and more attention. The insulation resistance detection function of the photovoltaic inverter is necessary to ensure the safe and reliable operation of the photovoltaic system and to prevent personal electric shock. How to realize the real and reliable detection function is very meaningful to meet the safety requirements and reduce the cost of the inverter. In non-i...

AI Technical Summary

Problems solved by technology

[0003] However, in the existing non-isolated photovoltaic grid-connected inverters, the insulation resistance detection circuit is mostly based on the earth equivalent of the chassis, and the prerequisite for accurate detection is that the chassis is well grounded

When the inverter is not well connected to the ground, the insulation resistance circuit cannot normally detect the parasitic impedance of the photovoltaic module to the ground. At this time, the connection of the machine to the grid will affect the machine itself and the human body

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