Title: PLL Based Solar Array Feeding Grid


    The use of renewable energy sources to meet the shortage of electric power, nowadays, is very common and also cheaper. Not only on grid level, it’s usage to drive the load of offices and houses is also common. The solar energy is the most common for this purpose. To utilize its power, as it is being DC in nature, inverter to convert it to AC is a must thing. There are many losses in this process hence we need an efficient inverter and also the one which maximize the power output of solar arrays. Moreover, there is a time when there is surplus power in the output and we need only a few of it to drive our load. With no wastage, we can send it to grid to earn and more importantly, to meet the shortfall (which is common on our country).
   The main part here is inverter. We need a highly efficient to inverter to eliminate the losses and to get the maximum power output. First, we designed a 3 phase inverter and checked its output by driving a three phase balanced load. Then we moved on to designing a highly efficient inverter (with efficiency exceeding >98%) that was HERIC (Highly Efficient and Reliable Inverter Concept). We did its simulations and tried to implement it on hardware.
   Then we used Precision Rectifier to measure the root mean square voltages of output of inverter and the grid i.e. distribution line in our case the supply we are getting from WAPDA). Zero crossing detector was also used to detect the frequency of the inverter and WAPDA. Current sensors were used to measure the current and to analyse its waveform.
   Now to feed the inverter output i.e. power from DC BUS BAR (Solar Panels), to the grid we have to synchronize all the parameters of the inverter and grid i.e. Vrms and Freq. For this purpose we are using PLL (phase lock loop) technique in which the output of the inverter is tracked till it matches with that of the grid’s. When the synchronization is done, it is then fed to the grid.

Advisor:   Arsalan A Raheem   

Group Members:

Name: Hafiz M. Osama
Phone: 0331-4220443

Name: Hussnain Saleem
Phone: 03320341022

Name: Touseef Akhtar
Phone: 03017180680

Name: Abdul Moeed