The post discuses the how to make a 3 phase inverter circuit which can be used in conjunction with any ordinary single phase square wave inverter circuit. The circuit was requested by one of the interested readers of this blog.
UPDATE: Looking for an Arduino based design? You may find this one useful:
The Circuit Concept
A 3 phase load can be operated from a single phase inverter by employing the following explained circuit stages.
Basically the involved stages can be divided into three groups:
- The PWM generator circuit
- The 3 phase signal generator circuit
- The mosfet driver circuit
The first diagram below shows the PWM generator stage, it may be understood with the following points:
The Oscillator and the PWM Stage
The IC 4047 is wired as a standard flip flop output generator at the rate of the desired mains frequency set by VR1 and C1.
The dimensioned push-pull PWM now becomes available at the E/C junction of the two BC547 transistors.
This PWM is applied to the input of the 3 phase generator explained in the next section.
The following circuit shows a simple three phase generator circuit which converters the above input push-pull signal into 3 discrete outputs, phase shifted by 120 degrees.
These outputs are further bifurcated by individual push-pull stages made from a NOT gates stages. These 3 discrete 120 degree phase shifted, push pull PWMs now become the feeding input signals (HIN, LIN) for the final 3 phase driver stage explained below.
This signal generator uses a single 12V supply and not a dual supply.
Complete explanation can be found in this 3 phase signal generator article
The circuit below shows a 3 phase inverter inverter circuit stage using H-bridge mosfets configuration which receives the phase shifted PWMs from the above stage and converts them into corresponding high voltage AC outputs for operating the connected 3 phase load, normally this would be a 3 phase motor.
The 330 high voltage across the indivdual mosfet drivers sections is obtained from any standard single phase inverter integrated across the shown mosfets drains for powering the desired 3 phase load.
The 3-Phase Full-Bridge Driver Stage
In the above 3 phase generator circuit (second last diagram) using a sine wave doesn't make sense because the 4049 would ultimately convert it into square waves, and moreover the driver ICs in the last design employ digital ICs which will not respond to sine waves.
Therefore a better idea is to use a 3 phase square wave signal generator for feeding the last driver stage.
You may refer the article which explains how to make a 3 phase solar inverter circuit for understanding the 3 phase signal generator stage functioning and implementation details.
Using IC IR2103
A relatively simpler version of the above 3 phase inverter circuit can be studied below, using the IC IR2103 half bridge driver ICS. This version lacks the shut down feature, therefore if you do not wish to incorporate the shut down feature, you can try the following simpler design.
Simplifying the Above Designs
In the above explained 3-phase inverter circuit, the 3-phase generator stage looks unnecessarily complex, and therefore I decided to look for an alternative easier option for replacing this specific section.
After some searching I found the following interesting 3 phase generator circuit which looks pretty easy and and straightforward with its settings.
Therefore now you can simply replace the earlier explained IC 4047 and the opamp section entirely and integrate this design with HIN, LIN inputs f the 3 phase driver circuit.
But remember you will have to still use the N1----N6 gates between this new circuit and the full bridge driver circuit.
Making a Solar 3 Phase Inverter Circuit
So far we have learned how to make a basic 3 phase inverter circuit, now we'll see how a solar inverter with a 3 phase output can be built using very ordinary ICs and passive components.
The concept is basically the same, I have just changed the 3 phase generator stage for the application.
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:
- A 3 phase generator or processor circuit
- A 3 phase driver power stage circuit.
- A boost converter circuit
- Solar Panel (appropriately Rated)
To learn how to match a solar panel with battery and inverter, you can read the following tutorial:
Calculate solar Panels for Inverters
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:
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
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:
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
it’s working in inverter 3 phase refrigerator compressor operate.???
Since it is a square wave design it might not be suitable for compressors.
Hi thanks for the post. What is the use of HV capacitors? What would happen if I omit them?
The HV capacitors are for controlling the switching high voltage spikes and protect the MOSFETs.
Thanks
Hello Swagatam,
Wht is the output rating of the circuit. I want to use it for driving a 220 V, 60 w 3 phase brushless motor. May I know if the fuse or other safety device for protection is required.
Thanks.
Vijay Sonawane
Hello Vijay,
The output power will depend on the specifications of the MOSFETs. The MOSFET rating can be selected in accordance with the power of the load. You can add a fuse in series with your output load.
Well explained article.
With the availability of so many advanced ICs, can’t it be made around a single IC signal generator and control circuit and another single IC for MOSFET. In short every thing built around just two chips.
Thank you very much. So far I haven’t come across any 3 phase driver IC having a built-in 3 phase generator. If you have any ideas please do let us know about it.
Dear Swagatam
Instead of the 4047, can I use the 50 hz 555 oscillator to directly drive the lm324 thee phase generator?
Hi Richard,
You can use 555 oscillator but the NPN/PNP transistors will be still required.
Maybe it’s possible to make sine inverter using IRS20957 (used in audio amplifier, class D)
Hi Sir, I am constantly studying your projects, I like them. They are explained in a simple and easy way. I don’t have that much experience but I have learned a lot from reading your articles, thank you for that. I want to make VFD to drive 3 phsae motor from single phase 230 VAC for 5Hp three phase motor in our farm. So which of your projects should be referred to? I would be very grateful if you could help me with this. – Sanika
Thank you Sanika, I am Glad you found my posts helpful.
However, presently i do not have a properly tested 3 phase VFD circuit with me, so it is not possible for me to solve your problem.
In near future, if I happen to get this circuit I will surely inform you about it.
Good Morning sir,
I studied below mentioned circuit.In that I have confusion about 10uf/1kv capacitor. Please it would be good if you could explain to me and what kind of it? Polarised or non-polarise?
Have a good day .
thank you Sir.
https://www.homemade-circuits.com/wp-content/uploads/2013/10/3-phase-inverter-with-parts.png
Hello Sanika,
I would recommend using a non-polar capacitor, which would work better than a polarized one.
Sorry Sir to distrub you again,
Please which capacitor ( 10uf/1kv product name just like 104/105) available in market? I searched a lot of but I confused to select.I want check all material availablity in market and after that I will be going to make it so please help for the same issue.
Awaiting for your positive response.
Thanking you Sir.
No problem Sanika!
If you are having difficulty in getting a single 10uF/1kV capacitor, you can try 10nos of 1uF/1KV in parallel, or 5nos or 2uF/1KV in parallel.
R/Sir,
I have 10uf / 500v capacitor, so how can do? Please suggest me.
OK, in that case you will need 4 of these capacitors. Make two series connections each having 2nos of 10uF/500V capacitors then connect these two series strings in parallel.
Est ce que ce circuit correspond pour le variateur de vitesse moteur asynchrone triphasé
Any 3 phase motor should work with this inverter.
Hey swagatam, I just wanted to ask whether the address mentioned on JustDial is still available or you it has been changed? We were actually planning to visit you.
Hello Shubham,
I have moved to Mira Road now. If you have any circuit related questions you can feel free to ask me here, I will be most happy to help you.
sir can you please mail us the address my mail id is kaifs06@gmail.com
I am sorry Kaif, meeting personally may not be possible because then I may have to meet with many other visitors also, which can be difficult for me.
Ohkayy can you please share your contact no. on my email because we are eagerly planning to meet you.
I am sorry Shubham, meeting personally may not be possible for me, I prefer discussing through comment conversation only….I hope you will not mind it.
Sir we are almost in bhayandar… you are probably our last hopee… pls don’t let us down. We are hoping for a positive response from your end. Or pls send us simple 3 phase inverter circuit diagram Input -12V dc and output – 230V AC each phase and only lamp load max 60W load
Hello Shubham,
There’s no simple circuit for a 3 phase inverter.
You will have to to build the one which is given in the above article, taken from the datasheet of the IC.
First you will have to try the following circuit and check with an oscilloscope whether it produces 12 V 3 phase signals or not:
https://www.homemade-circuits.com/wp-content/uploads/2013/09/oscillator.png
Once the above circuit is verified, then you can integrate the 3 phase signal to the input side of the following circuit:
https://www.homemade-circuits.com/wp-content/uploads/2022/08/3-phase-inverter-circuit.jpg
If you find the above concept difficult then you can try the following concept instead:
electronics-project-hub.com/three-phase-inverter-circuit-diagram/
can i visit your shop in mira bhayander and please share some contact details i am coming all the way from thane, i need a circuit diagram of 3 phase solar inverter (12 V input)(230 v output in each phase).
The circuit diagram is already given in the above article. You can see the circuit diagram just below the heading “Using IC IR2103”
However the problem is that this project is recommended for those who are expert in electronic concepts…it is not recommended for newcomers.
Sir, i have to make a 3 phase solar inverter and i am facing difficulties in that and since i am a final year student i have a deadline to get it completed by end of february can you please help me with making a circuit for 3 phase solar inverter
Hello Kaif,
3 phase inverter is not an easy project to build. It will require a thorough knowledge of electronics for completing the project successfully.
I would recommend to first try the concept explained in the above article, under the heading “Using IC IR2103”.
If you are able to complete this circuit successfully, then you can replace the mosfet +600V supply with a supply from a solar panel DC.
Hi Swagatam
Many thanks for all the interesting stuff on your site as its very helpful for a learner like me. As per an earlier request, I need a circuit to produce 115v 3 phase 400Hz to power a military artificial horizon using a 12v dc supply. I plan to use the 4047 based oscillator circuit feeding the LM324 and IC4049 based 3 phase generator circuit. The HIN and LIM will then be fed into the IR2103 based full bridge driver stage.
What value of R1,P1 and C1 in the oscillator do I require for 400Hz?
What is a shutdown mode and do I need it?
Do I need to feed 115v dc to the Mosfet drain?
Would it be better to use a 24v dc supply and if so what changes to the circuit would be required?
Many thanks
Thank you zoomer, I would recommend you to try the following circuit for the oscillator, since it looks easier and hassle free:
https://www.homemade-circuits.com/wp-content/uploads/2013/09/oscillator.png
But test it separately to see whether it generates the required 3 phase signal or not?
I am not sure about the part values for 400 Hz, you may have to set the values using a frequency meter.
MOSFET drain can handle any DC depending upon its drain/source voltage rating.
12V is the recommended voltage for the ICs.
Thank you for the reply. With regard to the alternative oscillator circuit. It does not have any power input and 3 outputs so how does it connect to the 3 phase generator circuit?
The following 3 phase circuit already has 4049 gates at the HIN, LIN inputs which will do the required conversions. Power input must be connected to the respective supply pins of the op amp.
https://www.homemade-circuits.com/wp-content/uploads/2022/08/3-phase-inverter-circuit.jpg
Ok so I think I understand. This circuit replaces the need for the oscillator circuit and connects directly to the driver stage. How is the 400Hz frequency set?
Yes that’s right. I think C1, and R1 can be adjusted appropriately to get the desired frequency at the output:
https://www.homemade-circuits.com/wp-content/uploads/2013/09/oscillator.png
the flyback buck/boost converter would usually have a snubber network across the transformer primary to absorb transients.
Hi Swagatam.
Thank you very much for the detailed explanations of the 3-phase inverter designs shown here.
I was hoping to make enough sense out of this article to make an inverter for my specific need:
I need 115V 400Hz 3-phase with just some 200 – 400mA output. It would ideally have an input of 12VDC and be small. It is is to drive a vintage artificial horizon instrument out of a WW2 aircraft. It has 3 low power gyroscopes in it that require this voltage and frequency. It is for demonstration purposes, NOT for use in an aircraft. 🙂
Kind Regards,
Joe Hovel, Australia
Thank you Joe,
It is possible to get 115V, 400 mA 3-phase AC from the shown designs. You can try the IC IR2103 based design which appears to be a good option. However for getting 115V you will need to supply 115 DC across the drains of the mosfets. If you are intending to get the 115V from 12V then you will have to first boost the 12V to 115V through a boost converter circuit and then feed it across the mosfet drains.
like it this idear l like learn form you but if are going teach me very well
I want to achieve a 3 standard phase output(415v ) from 12v batteries. I understand how to go about this up until the mosfet drver where you fed in 330V dc into the mosfet .
How will i get my desired out voltage(not for motor control) using your mosfet driver configuration
You will get the 3 phase voltages across the 3 wires that are connected to the motor. If you feed 330V Dc to the mosfet drains, then the output wires from the mosfets will produce 330V AC 3 phase square wave.
Hi
there is a little difference in opinion. to obtain 220vac line to line you will need 311VDC bus & for 415V ac line to line you will need 650VDC bus.
Hi, the output AC from the bridge is a square wave not a sine wave, so its value will be equal to the DC input, according to me.
4049ic connect
Hi Very interesting the 3 ph circuit .
I am thinking about driving a std 220v refrigeration compressor with this type of circuit .
Your thoughts on this application ?
Regards
Nico
Hi, thank you and glad you liked the post. I think fridge compressor require sine wave AC, so unless the above 3 phase inverter is converted to sine wave it can be unsafe to use.
i am confusing in pwm generator circuit where r1,p1,c1 what is the value of it
and 3 phase signal generator circuit where c1 =?
mosfet driver circuit what is the watt of 100ohm resister and which mosfet
and what is the value of ah battaery
can i use irf540 mosfet in this circuit and is it right one mosfet is n channel and another is p channel
plz help me this is my final year project
The formula is
f = 1/4.4RC
R = P1 + R1 and these should be in ohms.
C will be in farads
100 ohm is 1/4 watt
battery Ah and voltage will depend on the required inverter power output.
All mosfets are N channel, and its rating will again depend on the desired inverter power output