A smart street lighting energy controllers design and implementation (1)

0 introduction

As China's rapid economic development, increasing people's living standards, energy and resources become increasingly tight, power shortage has become the highlight of the restrictive national economic development.

Currently, lighting consumes about electricity production of 10% ~ 20%, and urban public lighting in lighting electricity consumption accounts for 30 per cent, and in recent years as the city light up slogan, national road number is still growing rapidly. Public street lighting and energy saving slogan will result. Usually there are two ways to save energy: energy saving light source is one; second, it is necessary to adopt reasonable control line. This article on the use of energy-saving light sources of use reasonable control circuitry to achieve energy-saving lamps. In power supply system, to avoid transmission line loss during and at the peak of electricity resulting in end voltage too low, power supply units are made of a high voltage transmission. So much higher than the street lamp under voltage lamps for the rated voltage. However according to my small city after 21: 00 at night, large and medium cities after 00: 00 am on the road almost empty. Resulting in a "few cars dilute lamp lighter" unreasonable. To avoid this situation, most cities and regions have adopted the developed countries had already eliminated in the original Street lamp light lights control method. This approach not only lead to uneven pavement illuminance distribution, and will reduce the lamp service life. This article uses the "three quarters of the year, a quarter of segmented" time-sharing control thought the purpose of achieving energy saving. At different times into different supply voltage operation, ensure that lamps Lighting, both to the electricity-saving slump period. While taking advantage of the power line technology implementation on street health monitoring.

1 system hardware circuit design

1.1 smart street lighting control system

The intelligent energy-saving lighting system consists of power detection circuit, real time clock, auto-transformer circuits, show circuit and carrier communication circuit.

The year broadly divided into three seasons to control the lights, in different seasons have different switch lamp time. From the light to turn off the lights based on local traffic and can be broadly divided into three stages (peak, normal, low) to control the lights. From real-time clock chip sets the current street lamp operating position accordingly, chip output control contactor coil cut-and-contact output control auto-transformer of three contact, corresponding to the four stalls, each stall corresponding to the corresponding lamp voltage. Because of the power transmission in the harmonic interference caused by electrical instability, should always detect Street lamp power to power the chip ATT7028 detect current or voltage too high or too low, the resulting message to AT89C51-chip, microcontroller and Fram comparison of information, if you find current or voltage too high or too low, the SCM will make adjustments to lower or raise the voltage to enable Streetlight overload, overvoltage, and other features for control, using the power line communication technology will be transferred to the monitoring of the situation. Principle diagram shown in Figure 1.

1.2 power detection circuit design

Power acquisition module mainly completed Street lamp current and voltage data acquisition.

The acquisition of the signal converted to ADC circuit may be collecting and processing analog signal, power chip converted to digital signals sent to the SCM, testing the voltage and current are overloaded, based on this to control circuit load voltage. Design with three-phase electric dedicated metering chip ATT7028A, suitable for three-phase three-wire and three-phase four-wire application, able to measure each phase as well as in-phase active power and functionality, while also measuring the RMS phase current, voltage, power factor, phase angle, frequency and other parameters, to fully meet the three-phase complex power multi-function Watt-hour meter needs. At the same time power signal into the FRAM AT24C24, the storage data is missing for active energy history query. ATT7028A provides an SPI interface, convenient and external measurement parameters between microcontroller and school table parameters of the transmission. Design application ATT7028A measuring current and voltage RMS, using the school tables SPI interface with the outside microcontroller made between delivery measurement parameters, in order to detect the valid values of voltage and current street lamp. In addition to detect overload, overvoltage and failure alarm.

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