The project is done in several phases. In the first phase, we have tried to develop the PWM square output for the high frequency MOSFETs to switch ON and OFF with high frequency so that it can drive the chopper to step-up the voltage from 12 V to 220 V. In our second phase, we have tried to lower the frequency which was produced from the first PWM which is 70 kHz to 50 Hz. It was a challenge for us because not only we have to change the frequency but also we have to change the nature of the output signal which is the square signal has to be changed to sinusoidal signal or close to it. We have tried a lot of ways to find the solution but each of them was a dead end. There were also other to solve this but as one of our objective states that this device should be cheap so that it could be used in the country side, so we could not go for that solution. So we have decided to use Arduino to produce the sinusoidal output.

In our final phase, we have used the arduino to produce almost sinusoidal signal to drive the low frequency MOSFETs to give an overall output of 220 V with 50 Hz. In addition to that, we have introduced another function which is called CHARGE CONTROLLER. This feature charges the battery connected to the device when the solar panel is producing electricity and at the same time deliver it to the loads. When there is no solar input, at that time the controller switches allowing the battery to discharge to the loads. There are also some LEDs to indicate the charge level of the battery.