Rapid Shutdown Device for Photovoltaic Systems

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Solution Overview

Problem

Existing rapid shutdown devices for photovoltaic systems are costly due to the need for each photovoltaic power generation module to be equipped with a corresponding device, as semiconductor switches struggle to achieve both high voltage resistance and low impedance characteristics, leading to high system costs.

Innovation Solution

A rapid shutdown device with a dual-switch redundancy design, utilizing mechanical switches like relays and semiconductor devices, which allows a single device to handle the entire string of photovoltaic power generation modules, reducing the need for individual devices per module and lowering costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If each photovoltaic power generation module is equipped with a rapid shutdown device using semiconductor switches, then the shutdown function is achieved, but the system cost increases significantly

Engineering Contradiction:

Improveshutdown functionVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple rapid shutdown functions into a single device by connecting photovoltaic modules in series strings that share common shutdown switches. Instead of equipping each module with its own shutdown device, the invention combines the shutdown functionality for multiple modules into one unified rapid shutdown device, thereby reducing system cost while maintaining safety.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rapid shutdown device is designed to handle entire strings of photovoltaic modules universally. The device can manage multiple modules through shared switches (first and second switches for normal operation, third and fourth switches for bypass), making a single device perform the function that would otherwise require multiple individual devices.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If semiconductor switches are used to achieve high voltage resistance, then the shutdown capability is improved, but the impedance increases

Engineering Contradiction:

Improvevoltage resistanceVSAvoidimpedance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite switching architecture that combines semiconductor switches (for controlled shutdown functionality and voltage resistance) with mechanical relay switches (for low-impedance normal conduction). This composite approach allows the system to achieve both high voltage resistance during shutdown and low impedance during normal operation by utilizing the complementary strengths of different switch types.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11532935B2Rapid shutdown device for photovoltaic system and control method thereof and protection system

Publication Date: 2022.12.20 DELTA ELECTRONICS (SHANGHAI) CO LTD

AI summary

The present disclosure provides a rapid shutdown device for a photovoltaic system, which is connected between a photovoltaic power generation module and a photovoltaic inverter and comprises an input port and an output port. The rapid shutdown device further comprises: a first switch and a second switch; a third switch and a fourth switch; a controller coupled to control terminals of the first switch, the third switch, and the fourth switch, and configured to control on and off of the first switch, the third switch, and the fourth switch, so that the rapid shutdown device operates in a normal state, a bypass state or a shutdown state.