Wednesday, August 7, 2013

Why microcontroller based ELC for microhydro



Micro hydro is an attractive choice for electricity generation in rural area or underdeveloped countries. There are abounding micro-hydro systems operating in our country Nepal. It plays a great role to provide electricity to local communities where grid power is inadequate or unavailable.
The micro hydro system is designed to provide electricity by using the water resources available in the local areas. By taking the advantages of head and flow, water is used to generate electricity. Micro hydro system is built with technology and materials that is found in local market. It consists of set that consists of synchronous generator, turbine and penstock pipe. Due to the availability of these components as well as technicians, installation of the project is cheap.
The problem seen during the operating of the micro-hydro systems is fluctuation in frequency generated by the generator which causes adverse effect in various electrical appliances. The generated voltage and frequency of these machines varies with varying load. A controller is required to solve this problem. The electronic load controller is required to control the frequency of the generated voltage in the micro hydro system. Whereas  the machines delivers the fixed amount of power, the ELC can be used to switch in or switch out a dumb load whenever the consumer load decrease or increase respectively.
Existing controller available in market has few defects which degrade its efficiency. Its performance is not good. Response time is high; load switching times is high which may cause damage to generator due to overload or under load. Cost is high which has made the controller system high.
We plan to use micro controller for the Pulse width modulation so that it can give real time output. Sense the voltage and frequency of the generator through the sensor. Sensor output will be used for input to micro controller and micro controller will generate PWM and switch the thyristor. In existing system, many electronics components are used and those are scheme specific. If we are to change the value of components, then whole system had to change but in case of microcontroller based Electronics Load Controller, can be tailored to each system by changing the software parameter.
Microcontroller based ELC are easy to design, install and maintenance. Our system can operate in Synchronous/Asynchronous system, 50/60 Hz and single/3-Phase. This system is completely electronics module so easy to operate in minimal supply. The cost will be cheaper by 60% compared to existing ELC. With the robust and reliable algorithm used, minor as-well as major changes can be easily handled. The overall size of each unit is reduced by about 40-50%. The system is self diagnostic and can be changed as per requirement.