Leakage current detecting fast protection circuit and protection method

A leakage current detection and protection circuit technology, used in emergency protection circuit devices, AC network circuits, circuit devices, etc., can solve the risk of personal injury and reduce the safety and reliability of the system, so as to reduce the time of protection action, enhance the Safety and reliability, the effect of reducing the risk of electric shock

Active Publication Date: 2018-08-17
YANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the case of excessive leakage current, the process of the controller calculating the effective value of the leakage current and then making judgments to generate corresponding actions will inevitably lead to a long delay, which increases the risk of personal injury to the operator and the safety and reliability of the system. reduce

Method used

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  • Leakage current detecting fast protection circuit and protection method
  • Leakage current detecting fast protection circuit and protection method
  • Leakage current detecting fast protection circuit and protection method

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Embodiment Construction

[0021] The present invention will be further described below in conjunction with specific embodiments.

[0022] The invention aims at the requirements of the new energy standard NB / T 32004-2013 standard for photovoltaic grid-connected inverters, and proposes a leakage current detection fast protection circuit and a protection circuit for rapid leakage current protection in the case of large leakage currents. method.

[0023] Such as figure 1 with figure 2 As shown, the protection circuit in the present invention is made up of the following components:

[0024] A current transformer 1, a self-excited oscillator 2, a fast protection circuit 3, a sampling resistor Rs4, a Chebyshev filter 5, a sampling conditioning unit 6, and a controller 7; wherein, the current transformer 1 can be composed of a rectangular magnetic hysteresis circuit The magnetic core with linear characteristics is wound into a coil; the controller 7 is composed of a digital control chip; the positive and n...

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Abstract

The invention discloses a leakage current detecting fast protection circuit in the field of power electronics. The leakage current detecting fast protection circuit comprises a current transformer installed on a loop to be tested. A secondary side output winding of the current transformer is connected with both ends of a self-excited oscillator. An output end of the self-excited oscillator is connected with an input end of the fast protection circuit. An input end of the self-excited oscillator is connected with a non-ground end of a sampling resistor, and at the same time, the non-ground endof the sampling resistor is connected with an input end of a Chebyshev filter. An output end of the Chebyshev filter is connected with an input end of a sampling conditioning unit. The sampling conditioning unit includes a signal voltage dividing resistor and an operational amplifier. The output end of the Chebyshev filter is connected with one end of the signal voltage dividing resistor, and theother end of the signal voltage dividing resistor is connected directly with an output end of the fast protection circuit and an in-phase input end of the operational amplifier in the sampling conditioning unit. An output end of the sampling conditioning unit is connected with a controller. The leakage current detecting fast protection circuit of the invention is safer and more rapid when detecting a large leakage current, and can be used in photovoltaic grid-connected power generation.

Description

technical field [0001] The invention relates to a photovoltaic inverter, in particular to a current detection and protection circuit of a photovoltaic grid-connected inverter. Background technique [0002] With the promotion and development of photovoltaic grid-connected technology, photovoltaic grid-connected systems have also received relevant national policy and financial support in my country. Photovoltaic grid-connected systems are generally composed of components, inverters, and grids. They are a low-voltage power distribution method. The interface between the grid and the load often uses an inverter system, but there will be a direct connection between the grid and the photovoltaic array in the system. However, there will be parasitic capacitance between the photovoltaic array and the ground, and the changing voltage will generate leakage current in the photovoltaic grid-connected inverter system, which will cause safety hazards and cause personal injury. In addition...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/32G01R31/02H02J3/38
CPCG01R31/50H02H3/32H02J3/383Y02E10/56
Inventor 尧永方宇王明南杨家俊张晓莉
Owner YANGZHOU UNIV
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