SI24488A - Safety switch of photovoltaic modules - Google Patents

Abstract

The invention describes a new design solution for the electronic circuit breaker circuit breaker for photovoltaic modules, which can safely and automatically shut off the complete photovoltaic power plant in the event of fire or maintenance. The safety circuit breaker of the photovoltaic modules is designed in such a way that, in the event of a failure of the mains voltage, the activation of the main safety switch or the triggering of safety sensors (fire, flood), each photovoltaic module is switched to a short circuit so that the complete power plant is free from electrical voltage. Subject of the invention relates to the field of switching technique - an electronic protective switch. The circuit breaker electronic circuitry consists of transistors (3, 4), a bistable electromechanical relay with two coils (1, 2) and the switch part of the relay (12), the capacitor (5.11) and the resistors (6, 7, 8, 9, 10). The technical problem solved by the invention is the triggering of the SET coil (2) of the bistable relay without external voltage and the reliable switching of the switching part (12) of the bistable relay, since with the resistor (10) and the condenser (11), the current and the voltage are protected, thereby protecting the contact a bistable relay system (12) (there is no arcing between contacts and welding of contacts).

Description

ISKRA-RELAYS d.d Statenberg 88 2321 Makole

DESCRIPTION OF THE INVENTION

Safety breaker for photovoltaic modules

The invention describes a new design of an electronic circuit breaker circuit breaker for photovoltaic modules that can safely and automatically shut off the complete photovoltaic power plant in the event of fire or maintenance. As photovoltaic modules continuously generate electricity throughout the day, the entire photovoltaic power plant is under high voltage. In the event of an emergency, it is not possible to physically disconnect individual modules from the network. Even switching off a switch that disconnects the PV network from the inverter to AC does not guarantee safety, since the entire photovoltaic power plant to the inverter is still energized. The circuit breaker automatically switches each individual photovoltaic module to a short circuit so that the complete power plant is free of electricity. The switch-off can be triggered manually (with a switch) or automatically (fire sensor). With safety breakers the photovoltaic power plant is yours. The invention describes a safety switch for photovoltaic modules, consisting of a printed circuit board with electronic elements, a bistable electromechanical relay, a housing and corresponding cable connectors.

The circuit breaker of photovoltaic modules is designed in such a way that in case of a power failure, activation of the main safety switch or actuation of safety sensors (fire, flood), each individual photovoltaic module switches into a short circuit so that the complete power plant is without electricity.

The subject of the invention relates to the field of switching technique - electronic protection switch.

Description of the solution known so far

The construction of a comparable safety circuit breaker for photovoltaic modules, as previously known, may result in overloading of the bistable electromechanical relay (switching contacts may be welded upon switching on) and thus failure of the safety circuit breaker.

• ·

Description of the present invention (new solution)

The circuit breaker electronic circuit consists of transistors (3, 4), a bistable electromechanical relay with two coils (1, 2) and a relay switch part (12), a capacitor (5, 11) and resistors (6, 7, 8, 9). 10).

When a high voltage potential (+18 to 30 V) is present at the input control terminal (13), a transistor (3) opens through the capacitor (5) and the resistor (3), thereby triggering the RESET coil (1) of the bistable relay. The switch part (12) of the bistable relay breaks the contact, leaving the terminal (14) at the normal voltage potential of the photovoltaic module (30 to 60 V). In decoupling the relay contacts, the capacitor (11) and the resistor (10) are of paramount importance, keeping the low voltage potential at the switch part (12) for a short time, thus preventing the formation of an electric arc on the contacts of the bistable relay.

When the input terminal (13) has a low voltage potential (0 V), the electronic circuit uses the stored energy of the capacitor (5) and triggers the SET coil (2) of the bistable relay via resistors (6, 8) and transistor (4). The switch part (12) of the bistable relay contacts, leaving a low voltage potential of the photovoltaic module (0 V) at the terminal (14). In making the relay contacts, a resistor (10) which restricts the current through the contact is essential, thus preventing the welding of the contacts of the bistable relay.

A technical problem solved by the invention is the actuation of the SET coil (2) of the bistable relay without external voltage, and the reliable switching of the switch part (12) of the bistable relay, since the resistor (10) and the capacitor (11) limit the current and voltage, thereby protecting the contact bistable relay system (12) (no arc between contacts and contact welding).

Claims (3)

1. The safety switch of photovoltaic modules is characterized in that it switches off the photovoltaic module without external excitation since the electronic circuitry uses the stored energy of the capacitor (5) and triggers the SET coil (2) of the bistable relay via resistors (6, 8) and transistor (4). 2. The photovoltaic module safety breaker according to claim 1, characterized in that the capacitor (11) and the resistor (10), while breaking the relay contacts, keep a low voltage potential at the switching part (12) for a short time, thus preventing the formation of an electric arc on the contacts of the bistable relay. 3. The photovoltaic module safety circuit breaker according to claim 1, characterized in that when closing the relay contacts, the resistor (10) limits the current through the contact, thereby preventing the welding of the contacts of the bistable relay.