Solar 3 Phase Inverter Circuit

In this post we learn how to design a simple solar 3 phase inverter circuit using just a few specific ICs.

We have already learned how to make a simple solar inverter circuit, in this article we'll see how a solar inverter with a 3 phase output can be built using very ordinary ICs and passive components.

Inverter Basic Requirement

For acquiring a 3 phase AC output from any single phase or a DC source we would require three fundamental circuit stages:

  1. A 3 phase generator or processor circuit
  2. A 3 phase driver power stage circuit.
  3. A boost converter circuit

One good example may be studied in this article which explains a simple 3 phase inverter circuit

In the present design we too incorporate these three basic stages, let's first learn regarding the 3 phase generator processor circuit from the following discussion:


3 phase signal processor circuit

How the Circuit Works

The diagram above shows the basic processor circuit which looks complex but actually it's not. The circuit is made up of three sections, the IC 555 which determines the 3 phase frequency (50 Hz or 60 Hz), the IC 4035 which splits the frequency into the required 3 phases separated by a phase angle of 120 degrees.

R1, R2 and C must be appropriately selected for acquiring a 50 Hz or 60 Hz frequency at 50% duty cycle.

8 numbers NOT gates from N3 to N8 can be seen incorporated simply for splitting the generated three phases into pairs of high and low logic outputs.

These NOT gates may be acquired from two 4049 ICs.

These pairs of high and low outputs across the shown NOT gates become essential for feeding our next 3 phase driver power stage.

The following explanation details the solar 3 phase power mosfet driver circuit


solar 3 phase inverter circuit

As may be seen in the above figure, this section is built across 3 separate half bridge driver ICs using IRS2608 which are specialized for driving high side and low side mosfet pairs.

The configuration looks quite straightforward, thanks to this highly sophisticated driver IC from International rectifier.

Each IC stage has its own HIN (high In) and LIN (low In) input pins and also their respective supply Vcc/ground pins.

All the Vcc are required to be joined together and connected with the 12V supply line of the first circuit (pin4/8 of IC555), so that all the circuit stages become accessible to the 12V supply derived from the solar panel.

Similarly all the ground pins and lines must be made into a common rail.

The HIN and LIN should be joined with the outputs generated from the NOT gates as specified in the second diagram.

The above arrangement takes care of the 3 phase processing and amplification, however since the 3 phase output should be at the mains level and a solar panel could be rated at a maximum of 60V, we must have an arrangement that would enable boosting this low 60 volts solar panel to the required 220V or 120V level.

Using IC 555 Based Flyback Buck/Boost Converter

This can be easily implemented through a simple 555 IC based boost converter circuit as may be studied below:


Again, the shown configuration of the 60V to 220V boost converter looks not so difficult, and can be constructed using very ordinary components.

The IC 555 is configured as an astable with a frequency of approximately 20 to 50 kHz. This frequency is fed to the gate of a switching mosfet via a push pull BJT stage.

The heart of the boost circuit is formed with the help of a compact ferrite core transformer which receives the driving frequency from the mosfet and converter the 60V input into the required 220V output.

This 220V DC is finally attached with the previously explained mosfet driver stage across the drains of the 3 phase mosfets for achieving the 220V 3 phase output.

The boost converter transformer can be built on any suitable EE core/bobbin assembly using 1mm 50 turns primary (two 0.5mm bifilar magnet wire in parallel), and secondary using o.5 mm magnet wire with 200 turns


40 thoughts on “Solar 3 Phase Inverter Circuit

  1. Have questions? Please feel free to post them through comments! Comments will be moderated and solved ASAP.
  2. Please sir I need a substitute for this APTCC1203 its a FET. I have searched online but I couldn't get the datasheet. Its for my 1000W SMP inverter. Please help me sir.

    • Musa, if you can tell me roughly about the voltage and current values your FET is being supplied with then probably I would be able to suggest an appropriate equivalent. also let me know whether it's a N channel or a P channel fet.

  3. I have no details about the FET. But, It just a FET used in the H-bridge output of my newly bought 1000w smp 12v dc to 220v ac inverter. I mistakenly connect the output of my inverter to ac mains. In trying to make a change-over.

  4. please, i need some clearifications on the circuit
    1. what is the frequency to be generated initially from 555 to be fed into the ic 4035 to generate 3 phase @ 50Hz?
    2. in the boost circuit, does the 60v step up transformer determine the over all power rating of this inverter system or what?
    3. in the power mosfet driver circuit, does the mosfets determine the over all output rating of the sysytem?
    4. will the phases be connected directly to power load ?
    5. i can't see where the shutdown SD is connected in the circuit

    • 1) it should be 50Hz.
      2) yes the 60v trafo determines the ultimate power, along with the mosfets.

      4) the indicated 3 phases will go to the three wires of the load
      5) shut down is an optional feature which will need an error amplifier integration for the implementation.

  5. thanks for the clarifications.
    can i use more than one mosfet in parallel in the boost circuit stage for more power handling capability in my design or it doesnt matter?

  6. hello SWAGATAM MAJUMDAR, My Name is Lufuno, I had been following you for some time, I have a great need of a Single Phase MPPT Solar Pump Inverter , can you help me with the design, I appreciate your help

  7. Thanks Mr Swagatam , i will await the post , it also more similar to what positivethinker 7512 is asking for , but my source will be solar panels

    Pump Wattage 370 Watt (0.37 KW),Pump Input Voltage 220V AC three phase ,I want to drive the pump directly from solar Power source , no battery

  8. Dear sir i want to make 36/48/60vdc (solar power ) to three phase 440vac for 2A induction motor load.
    please give me an idea with detail of components.
    awaiting your response

  9. Hi Swagtham , can you please help me with the schematic /idea of a 555 IC based boost converter circuit for my solar panel of 44VDC to 310 VDC , need to feed the output 310 VDC to the solar pump inverter you suggested to me avoiding the need of transformer and reducing the amount of solar panels

    • Hello Swagatam , thanks for a prompt reply, got few questions

      1. just a bit of clarity on IC 555 12V input using resistor an emitter follower dropping stage. or an example.
      2.Any suggestion on the Mosfet , is it suppose to an N-Channel or P-Channel
      3.Any Replacement for BA 159
      4.if I feed the buck booster with 44V 750 Watts from the solar panel will the power on the output power change or remain the same like 310 VDC 750 Watts
      5. On the other circuit I am struggling to find IRF450 , it is discontinued by our supplier, any replacement.

      Thanks in Advance

    • Thanks Lufono,

      please refer to this article and see how the BC546 is used for supplying 9V to the IC from 48V input

      the mosfet could be an IRF840 if IRF450 is not obtainable.

      BA159 could be replaced with FR107 or any other similar.

      The output wattage will be little less than 750 watts, the output current will be 750/310 = 2.4 amps

  10. I have made the circuit for 3 phase inverter , i have a problem while running a motor. I think i am wrong in my code. Can give a code for driving a bldc motor with gate driver(ir2110). Advance thanks

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