Solar 3 Phase Inverter Circuit - Detailed Working Explanation and CircuitDiagram

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 converter circuit

How it 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

Note: The shut down pin must be connected to the ground line if not used, otherwise the circuit will not work

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:

IC 555 Based Flyback Buck/Boost Converter

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

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Ambrose said…
Sir. Thanks I have gotten the answer in the 3 phase inverter post. Thank you very much.
musa kizito said…
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.
Swagatam said…
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.
musa kizito said…
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.
Swagatam said…
for a 12V battery input you can try using an IRF540 fets if it's an Nchannel, which it will be more often....for a pchannel you can try IRF9540
omooh Kole said…
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
Swagatam said…
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.
omooh Kole said…
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?
Swagatam said…
first test with single mosfets, if everything goes well, then you can try adding more mosfets in parallel for increasing wattage gain of the output
Adrian Vivar said…
What's the power delivered by this circuit? And how can I increase it if I want to?
Swagatam said…
the power rating depends on the mosfet power could be upgraded to any desire level by adding more mosfets in parallel
Riscy said…
IRS2608 is not the same as shown in schematic, it is 10 pin with SD, what the actual PN?
Swagatam said…
I think there was a mistake while typing the number.

please try IR2110 instead
ningrat_edan said…
hello sir Mujamdar Swagatam ,
get you help me to make the inverter using ic NE555 using ferrite transformer with 12volt input ? thank you so much for your help
Swagatam said…
Hello ningrat_edan, if possible I'll try to publish it soon...
ningrat_edan said…
Okay sir , I really thank you for having responded to my question
I patiently wait for the results
Swagatam said…
thanks ningrat, I have updated the design below
vhafuwi said…
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
Swagatam said…
Hi Lufono, I'll try to post it soon in this website
vhafuwi said…
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
Swagatam said…
Thanks Lufono, I'll try to update it as as soon as I finish my earlier pending requests.
Swagatam said…
Thanks Lufono, can you please mention the voltage rating of the panels, higher voltage rating is recommended to facilitate smaller inverter size and lower current operation....

vhafuwi said…
Hi Mr Swagatam , thanks for the prompt reply, My Solar Panel Voltage rating is 36V
Swagatam said…
OK got it thanks!
Sir in your boost converter (60v from solar panel) that IRFP450; can I replace it with IRFP460 without any change to the circuit?
Swagatam said…
Hi Kabir, yes that's possible you can do it....
Unknown said…
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
Swagatam said…
yes it's possible, you can use the above mentioned circuit for your specific needs.

If you find the first circuit a little complex, you can try the following instead
vhafuwi said…
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
Swagatam said…
Hi Lufono, you can try the first concept as presented in the following article

however the IC 555 section must be fed with a 12V using resistor an emitter follower dropping stage.

for the upper transistor you can use a mosfet for better power handling
vhafuwi said…
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
Swagatam said…
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
Nihal said…
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
Swag said…
sorry did not properly understand your query, please elaborate more
shivaji said…
sir, plz can i know which type of MOSFET and IC used in last circuit of three phase inverter circuit.
Swag said…
Shivaji, the mosfet specs will depend on the load wattage specs

IC can be any half bridge driver, for example IRS2608 or LM5109
Matthias said…
good day please how do i get the exact diagram for the pin connection for the NOT gate N3 to N8?
Swag said…
please check the datasheet of the IC, you will get all the details in it....
Afam Nzoiwu said…
You applied three 10uf/1kv capacitors in all phases instead of one. Why?
Swag said…
One will do, it got duplicated while drawing the stages, I hope you understood now!
heelicoms said…
Dear Swag.
I have A vfd circuit but i dont know if it works .Kindly check it for me and advice
How can i upload .

Swag said…
Dear helicom, you can send it to homemadecircuits
If it is possible, I will check it out and provide suggestions.
chris kenbert luna said…
can you explain further how exactly 4049 ic will split the generated three phases into pairs of high and low logic outputs??

base on what i understand, when you input for example 1 on an logic inverter the output will be 0 and vice versa. lets say i input 1 on a two parallel logic inverter the ouput will be 0 and 0. i dont think i will be able to get an output of high (1) and low (0) using the above configuration of the cmos hex.

can you please explain it further maybe im just confused or something.
chris kenbert luna said…
on the 555 section, you put a 220uF accross the R1, R2 and C. does it affect the output of the desired frequency? i searched a frequency calculator for 555 but it doesnt have any capacitor accross the the parameters for determining the output freqency? in terms of the formula for frequency calculation R1, R2 and c are the only parameters.
Swag said…
The 4049 gates are arranged NOT gate inverters, meaning the outputs from each gate will be opposite to their respective input volatge polarities at any given instant. This allows each of the outputs to generate complementary logics sequencing at the applied 3 phase 120 degrees phase difference and at 50Hz frequency. Together it can become a complex process which cannot be interpreted mentally or verbally, you will need a scope to confirm the waveform.
Swag said…
OK, I agree, there's a mistake in the drawing, while answering the previous comment I was imaging the following design:

however the above article needs a correction, will do it soon.
chris kenbert luna said…
sir on the above boost converter, you use a transformer to step up the 60V DC from the panel into 220V DC however if im not mistaken transformers cannot step up DC voltage.
Swag said…
the 220uF is only for providing extra filtration and for grounding any residual voltage spikes or transients in the line
chris kenbert luna said…
so it will not affect the output frequency?? if im not mistaken sir and as far as i know that paralleled capacitor will contribute a change on the computation of the frequency.
Swag said…
Hi Chris, the mosfet will be switching the transformer primary with a pulsating DC, therefore it won't be a constant DC, rather a switching DC at the trafo primary.
Swag said…
The 220uF cap is connected across the supply lines, it has nothing to do with the 555 timing, the timing capacitor is shown as "C", this capacitor decides the output frequency of the IC
kola said…
I made the phase converter it worked but the 4035 got hot after feeding driving signal
what do I do?
Swag said…
Hi, try adding a 1000uF capacitor right across the +/- pins of the IC, and see if that helps!

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