Energy includes two types: Renewable energy and non-renewable energy. At present, our country as well as many other countries are exploiting 4 commercial energy is traditional hydropower, coal, oil - and gas atoms. In addition to hydropower as renewable energy, the remaining 3 types of non-renewable forms of energy, that is exploited to a certain level will end.
Use energy needs associated with environmental sustainability, restrictions affecting climate change. And the new trend of using energy resources avail endless, environmentally friendly and renewable energies such as solar, wind, tidal, wave, hydro, nature waste, ... At present, most people are aware of solar energy is very large, easily obtained, and is well suited to the climate in Vietnam. Vietnam is a country with an average of 1 day sun is high, about 5 hours of sunshine / day. This is a very favorable conditions for efficient use of this energy source [Link Removed
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A public lighting system needs to meet the conditions for stability, reliability, safety and urban landscape while saving electricity is a requirement of urban areas and cities. To accomplish this goal need to adopt measures illumination-application of new technologies for energy saving street lighting and traffic in Vietnam today.
2. System Requirements
A block diagram for a lighting columns as follows:
The system will consist of building components:
- Solar 12V DC power supply [Link Removed
- Power adapter (charger, DC / DC, Inverter DC / AC, battery)
- Power supply (12V power supply for LED lights).
- LED lighting.
- LED controller.
The principle of the system:
- The lampposts activities independently. Each light pole will be attached a system of LED lights, one controller.
- Control the light by the potentiometer controls for the lighting circuit. For example, when it starts up, the lights began to dim, when it gets dark, the light stays permanently at full capacity ..
- Programming schedule for lighting by time of day, by day of week, holidays, timetables for outdoor lighting, ensure adequate lighting for security requirements and safety . We use these buttons to control the lighting system. For example, the default button when the light sensor detects the light does not light, turn off the light sensor detects light ...
- Solar cells to provide power to the system circuits, sensors .. battery to recharge for the night will be used to provide the LED system.
3. Theoretical Foundations
3.1. DC / AC
- Use solar power
- Power Supply AC 220V - 50Hz stable
- Solar Cells
- The Battery
- Battery Chargers
- The converter Converter DC / DC
- The inverter DC / AC (12VDC/220VAC)
- Solar DC power supply, the charger will be passed on Battery charger. The inverter takes the DC power input and the output is 220V 50Hz AC power.
During normal operation, the input DC voltage is supplied by solar panels. When the battery is charging systems, high voltage stage to accept the battery down and charge the battery voltage level. When the battery is fully charged, the battery charger switch to stand-by mode.
In the case of input power failure occurs, the system will take a way from the battery source. When this adapter DC / DC mode work boots. The purpose of the converter DC / DC to DC power is increased and the removal of the unwanted components in order to provide stable DC power for the inverter. The converter DC / DC will generate output voltages 440V between the poles, 220V-220V at the anode and the cathode.
Inverter DC / AC converter using a DC voltage of the output pulse voltage is approximately sinusoidal shape. The purpose of the adapter is to provide a voltage output frequency is determined by the reference signal. A sinusoidal reference signal is compared with 1 strip of symmetrical triangular wave signal resulting pulse width modulated.
Pulse input range is 1 LC filter, creating a sinusoidal voltage supply to the load. When 12V DC input is provided by solar cells due to any other reason that, the system still provides 220V AC power load stability.