Multipath MPPT input photovoltaic inverter insulation impedance detection device and method

A photovoltaic inverter and insulation resistance technology, which is used in photovoltaic system monitoring, impedance measurement, photovoltaic power generation, etc., can solve problems such as failure of the solution, inability to accurately detect the insulation resistance value of the system, and achieve high precision.

Active Publication Date: 2016-02-24
JIANGSU GOODWE POWER SUPPLY TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this solution does not actually detect the magnitude of the insulation resistance value, but judges whether the insulation resistance is qualified according to the difference between the theoretical and actual voltages, and wh

Method used

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  • Multipath MPPT input photovoltaic inverter insulation impedance detection device and method
  • Multipath MPPT input photovoltaic inverter insulation impedance detection device and method
  • Multipath MPPT input photovoltaic inverter insulation impedance detection device and method

Examples

Experimental program
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Embodiment 1

[0045] Embodiment 1: The sub-circuit connected between the positive pole PVn+ of n solar panels in the photovoltaic system and the ground includes n branches that can be turned on and off independently, and each branch is connected to a solar cell in the photovoltaic system. Between the positive pole PVn+ of the board and the ground, each branch includes a first switch and a first resistor connected in series. The sub-circuit connected between the negative pole PV- and ground includes a second switch and a second resistor connected in series.

[0046] as attached image 3 As shown, in this embodiment, taking a dual-channel MPPT input photovoltaic inverter as an example, it is connected to the positive poles PV1+ and PV2+ of the two solar panels in the photovoltaic system, and the negative poles of the two solar panels are connected to PV -. The insulation resistance of the positive pole PV1+ to the ground is X1, the insulation resistance of the positive pole PV2+ to the grou...

Embodiment 2

[0077] Embodiment two: as attached Figure 5 As shown, compared with the first embodiment, this embodiment is based on four MPPT input photovoltaic inverters. It is connected to the positive poles PV1+, PV2+, PV3+, and PV4+ of the four solar panels in the photovoltaic system, and the negative poles of the four solar panels are connected to PV-. The insulation resistance of positive PV1+ to ground is X1, the insulation resistance of positive PV2+ to ground is X2, the insulation resistance of positive PV3+ to ground is X3, the insulation resistance of positive PV4+ to ground is X4, and the insulation resistance of negative PV- to ground is X5 . The sub-circuit connected between the positive poles PV1+, PV2+, PV3+, PV4+ of the four solar panels in the photovoltaic system and the ground includes four branches that can be turned on and off independently, and the positive poles PV1+, PV2+, PV3+, and PV4+ are respectively connected to one Each branch includes a first switch and a f...

Embodiment 3

[0078] Embodiment 3: The sub-circuit connected between the positive pole PVn+ of n solar panels in the photovoltaic system and the ground includes n branches that can be turned on and off independently, and each branch is correspondingly connected to a solar cell in the photovoltaic system Between the positive pole PVn+ of the board and the ground, each branch includes several first resistors connected in series and a first switch connected in parallel to both ends of one first resistor. The sub-circuit connected between the negative pole PV- and the ground includes several second resistors connected in series and a second switch connected in parallel to both ends of one second resistor.

[0079] as attached Figure 6As shown, the dual-channel MPPT input photovoltaic inverter is still taken as an example. It is connected to the positive poles PV1+ and PV2+ of the two solar panels in the photovoltaic system, and the negative poles of the two solar panels are connected to PV-. ...

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Abstract

The invention relates to a multipath MPPT input photovoltaic inverter insulation impedance detection device which is connected with a multipath MPPT input photovoltaic inverter connected with a photovoltaic system and used for detecting the ground insulation impedance value of the photovoltaic system. The multipath MPPT input photovoltaic inverter is connected with the positive electrodes PVn+ and the connected negative electrodes PV- of n solar cell panels in the photovoltaic system. The ground insulation impedance of each positive electrode PVn+ is Xn, and the ground insulation impedance of each negative electrode is Xn+1, wherein n is a positive integer greater than or equal to 2. The insulation impedance detection device comprises at least two paths of sub-circuits which can be independently on and off so as to change access resistance. At least two paths of sub-circuits are respectively connected between the positive electrodes PVn+ and the ground and between the negative electrodes PV- and the ground of the n solar cell panels in the photovoltaic system. The circuit is enabled to be in different states via on/off of each sub-circuit so that the ground insulation resistance value can be accurately detected based on different states of the circuit, and precision is relatively high.

Description

technical field [0001] The invention belongs to the field of photovoltaic power generation, and in particular relates to an insulation resistance detection device and method applied to a photovoltaic inverter with multi-channel MPPT input. Background technique [0002] In a photovoltaic system, the insulation resistance of the DC side to the ground characterizes the insulation performance of the DC system. If the impedance is too low, the leakage current generated by it will pose a threat to people. Therefore, the current safety standards require that when the DC-to-ground insulation resistance is less than a certain value, the system is not allowed to operate in parallel with the grid. Based on this, the photovoltaic inverter needs to detect the insulation resistance value of the photovoltaic system. Multi-channel MPPT input inverters share PV-connection. Taking dual-channel MPPT input inverters share PV-connection as an example, the basic circuit topology is as follows: ...

Claims

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Application Information

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IPC IPC(8): H02S50/00G01R27/18
CPCY02E10/50
Inventor 曾维波黄敏方刚卢进军
Owner JIANGSU GOODWE POWER SUPPLY TECHNOLOGY CO LTD
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