simplest modified sinewave inverter without microcontroller


Posted on Feb 5, 2014

Most of the inverters in the market uses modified sinewave for better output at competitive cost. The modified sinewave unit uses a 50% fixed PWM squarewave and the hikes are balanced by a capacitor to produce almost a sine wave. This is called quasi sinewave having THD around 25-28% while squarewave inverters have 45% THD and pure sinewave invert


simplest modified sinewave inverter without microcontroller
Click here to download the full size of the above Circuit.

ers have just 3% THD. So, to form a modified sinewave inverter of 220V, we have to generate a 4 phase signal which has 25% 0V, 25% +311V, 25% 0V and 25% -311V. Thus, by series resistor-ed capacitor, the waveform becomes a quasi sinewave. In the driving section of push pull MOSFET sets (2 sets) we have to provide the following pulse, Now this requires a controlled bistable multivibrator whose output is set to off in 50% time. But we will use here a simple replacement for that. It`s a 4017 decade counter IC. We`ll use it to generate 4 pulses and the fifth state would be reset and this creates our required pulse. Then we just connect two non-consecutive outputs to MOSFET section to generate output. But there`s a tricky part in the clock and frequency. Since 4017 decade counter IC don`t have inbuilt clock generator, it requires external CP. For this we`ll use 555 timer IC and for each CP the output changes one step, but we need 4 changes for a complete 360 ° cycle. Hence, to make a 50Hz output, we need to set 555 timer IC to 200Hz. Please note that following circuit only shows upto outputs from oscillator, you need to connect MOSFET pairs at the outputs for driving the Inverter Transformer.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    TA8210AH - 2 x 22W BTL Car Amplifier Circuit
    PC Fan Speed Controller - For a Low-Noise PC
    Arduino solenoid project behaves strangely when operated on PC power supply
    Cellphone-Based Device Control With Voice Acknowledgement
    high current 10 to 20 amp automatic
    electronic mouse trap
    curve tracer adaptor schematics
    RF2126 high efficiency amplifier for 2.45 GHz ISM
    SMPSU With A Relay
    Use opa37 composed of the head preamplifier circuit diagram



    Top