Design scheme of grid-connected LED environmental protection billboard power supply system

1 Introduction

Solar photovoltaic lighting equipment has established an important position in the lighting industry by virtue of its features of energy saving, environmental protection and easy installation. In recent years, with the continuous improvement and development of the commoditized market, the advertising business has become larger and larger, and more and more energy has been invested in the advertising business. Based on the concept of environmental protection and energy saving, there are already many companies producing solar billboards on the market, but these billboards generally do not fully consider how to maximize the battery energy conversion rate and service life.

This paper analyzes some problems that are not fully considered in the popular controllers on the market, and on this basis, a set of energy-saving grid-connected LED environmental protection billboard power supply system design scheme is proposed.

2. Overall block diagram of grid-connected LED environmental protection billboard power supply system

The grid-connected LED environmental protection billboard power supply system is composed of solar cells, commercial power, lead-acid batteries, LED lights, drive circuits and controllers. A basic grid-connected LED environmental protection billboard power supply system, the functional block diagram shown in Figure 1.

Functional block diagram of grid-connected LED environmental protection billboard power supply system

(1) The solar panel is the main source of energy for the grid-connected LED environmental protection billboard power supply system. Its function is to directly convert solar energy into electrical energy and store it in lead-acid batteries.

(2) The control circuit controls the charging phase of the lead-acid battery to realize the trickle, constant current, overcharge, and float charging modes of the battery, and at the same time controls the power supply of the battery and the commercial power to the LED billboard.

(3) Lead-acid batteries are used for energy storage and for LED billboards.

This system mainly accomplishes the purpose of energy saving from the following points:

(1) Use lead-acid batteries as the energy source of the control system to reduce the consumption of mains electricity and realize the full use of clean energy.

(2) According to the characteristics of the photoresistor, control the approximate charging time of the lead-acid battery. Generally speaking, under good weather conditions, the sunlight is the strongest and the light energy is the most sufficient at noon, and the conversion efficiency of the solar panel per unit time is the highest. At this time, the lead-acid battery is charged to fully utilize the solar energy, and the time required is the shortest.

(3) The clock chip feeds back the time signal to the single-chip microcomputer, and the single-chip microcomputer controls the night working time of the LED advertising lamp in real time to reduce unnecessary energy waste.

(4) The advertising lamp adopts LED lamp, which has the characteristics of low voltage, higher brightness and energy saving compared with the same power lamp.

3. Hardware design of the control system

3.1 Design of power supply module

(1) Design of single-chip power supply module and CN173 special battery charge management chip power module power supply of single-chip power supply module and CN173 special battery charge management chip power module are derived from 12V lead-acid battery and solar battery respectively, using LM2575T-ADJ as voltage conversion chip, Obtain 5V and 15V regulated power supply respectively.

(2) The design of the LED power supply module of the LED billboard by the city power. The 220V city power of the standby power supply is reduced, rectified and filtered to obtain the same voltage as the lead-acid battery to supply the LED billboard, so that the LED advertising lamp can work stably. The power module circuit is shown in Figure 2.

Power module circuit

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