Pure sine wave inverter using PIC microcontroller

MY final year project


Pakistan has been facing load shedding due to electricity demand being more than production power of national grid, and unable to execute plans to enhance power production because of shortage of budget. But Pakistan is blessed with many renewable and nonrenewable energy resources. All what we need to do is wise and best utilization of resources.

In our country we are rich in renewable energy sources, in summer sun shines about eight to ten hours per day in most parts of country. Similarly in winter duration of sunny day is although shorter but still it is there. On the other hand we are blessed with wind energy as well, that is comparatively lesser than solar energy. We can utilize this energy to make user independent in power production.


This project deals with basic understanding of hybrid pure sine wave inverter and its implementation. The hybrid inverter is designed to utilize two sources e.g solar and wind. Implementation process is sub divided into several parts. Initially DC to DC converter using push pull topology is simulated at Proteus, and then is implemented on hardware. Then next part is to simulate inverter using H bridge topology and its hardware implementation. SPWM is used to generate pure sine wave To obtain a pure sine wave a LC filter is designed. At the end, since output of sources is no constant, so in order to regulate their voltage, voltage regulator using Buck topology is designed in MATLAB, its response is controlled using PID in Proteus and then hardware is implemented.

pure sine wave inverter implementation and circuit diagram

pure sine wave inverter implementation and circuit diagram

Basic review of project:

A hybrid system combines solar and wind technologies together. Both photovoltaic and wind generator use DC power. So an inverter is required to change the direct current into alternating current. The DC-AC inverters usually operate on Pulse Width Modulation (PWM) technique. The PWM is a very  advance  and  useful  technique  in  which  width  of  the  Gate  pulses  are  controlled  by  various mechanisms. PWM inverter is used to keep the output voltage of the inverter at the rated voltage (depending on the user’s choice) irrespective of the output load .In a conventional inverter the output voltage changes according to the changes in the load.  To  nullify this effect of  the changing  loads,  the  PWM inverter  correct  the  output  voltage  by  changing the width of the pulses and  the output AC depends  on  the  switching  frequency  and  pulse  width which  is adjusted according to the value of  the load connected  at  the outputs as to  provide  constant rated output. The inverters usually operate in a pulse width modulated (PWM) way and switch between different  circuit  topologies,  which  means  that the  inverter  is  a  nonlinear,  specifically  piecewise  smooth system. In addition to this, the control strategies used in the inverters are also similar to those in DC-DC converters. Both current-mode control and voltage-mode control are employed in practical applications.

pure sine wave inverter implementation and circuit diagram

pure sine wave inverter implementation and circuit diagram

In order to maximize output it is important to select   to select an inverter with the following characteristics.

  • High efficiency
  • Low standby losses
  • High Surge capacity
  • Low harmonic distortion

All grid connected inverters are pure sine wave inverters. Pure sine wave inverters are used to operate sensitive electronic devices that require high quality waveform with little harmonic distortion. In addition they have high surge capacity which means they are able to exceed their rated wattage for a limited time. This enables power motor to start easily which can draw up to seven times their rated current during startup. Virtually any electronic device will operate with output of pure sine wave inverter.

Application of PSW Inverter:

Some electronic devices may pick up inverter noise while operating with modified wave form. Fluorescent tube light works smoothly with pure sine wave inverter. Some appliances such as microwaves, drill machines, clocks or speed motors will not produce full output, if they don’t use sine wave current , moreover they may damage the equipment,. Some loads such as dimmers will not work at all.

It is safe to say any electronic device that requires sensitive calibration can only be used with pure sine wave inverters.

To know about hybrid pure sine wave inverter design and implementation including hardware and programming parts of this project, click on following link:

Pure sine wave inverter A-Z

Keep visiting my blog for more practical knowledge and final year project ideas.Remember me in your prayers in return.

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