how to build your own inverter

                                                      welcome to my blog
                      how to build an inverter from the scratch.  
by freeborn Emmanuel

article contents.
1. about me.
2. introduction to inverter. 
3. type of inverter. 
4. what makes up an inverter                                              
5. inverter oscillator.
6. inverter power circuit.
7. inverter transformer.   
8. how to assembled the inverter circuit.
                                                                      
                                                                about me.
am freeborn Emmanuel, am into inverter, battery charger and automatic change over for generator and stabilizer designing. i do design locally made inverter for house and office use and i do install solar panel with inverter, i do design solar charge controller and lots more. all this are product of herd work and passion. am so passionate about renewable energy and i enjoy spending much time at home making research and experiment of all type of inverter design and other electronic circuit and am quick in understanding and am very smart, if i should tell the story how it all started it well be so unbelievable but you see with so much passion and herd work and above all faith in God i can now design an inverter and other use full electrical system for my self and for friends and other people who need my service, i also do maintenance on electrical system, and i do help student with there project and lots more.
         
                                              introduction to inverter.
what is an inverter?. inverter is an electronic system that convert DC (direct current) in to AC (alternating current). inverter is a noiseless power generator and it can be use to power home and office and other electrical appliances.
                                                   how dos it work?
how it work is very simple if you have a battery lets say a car battery and you want to power your TV set with your car battery you will need an inverter to convert the current from the battery which is 12V DC current into a useful 220V or 120V AC current. 
when using an inverter to power any electrical appliances the battery which is the main source of energy will be discharging little by little and after some time the battery will discharge to a point that the inverter will have to short it self down because of low battery in that case you will have to use a battery charger to recharge the battery back to normal.        

                                     type of inverter
some inverter are automatic which means the inverter turn on automatically when there is power outage and when power is restore it automatically switch to standby mood and start charging the battery. 
some automatic inverter with in-build charger do not have charge control some can overcharge the battery and some are very slow when charging but many automatic inverter in the market have battery full cut off and some are not too slow when recharging battery it all depend on the product and specification design of the inverter.
some inverter do have in-build charger but are not automatic, you will have to torn off the inverter and then switch on the charging switch before it can start charging and you have to change over your load manually.
some inverter do not have charger and are not automatic its just an inverter that convert DC to AC nothing else added to it. all this have to do with design specification.                                          
                                                           inverter wave form
there are deferent type of inverter output wave form, some inverter are sine wave, and some are modify sine wave, and some are square wave.

                                                             sine wave inverter
A sine wave inverter have a smooth output wave form, how do you know this? when you use a sine wave inverter to power a fan it will work with out making a homing sound and it have the ability to power electrical compressor and the compressor will work with its normal power rating. a sine wave inverter is very good for a house use appliances. 

                                                           modify sine wave inverter
modify sine wave inverter is similar to a sine wave inverter but its output wave is not as smooth as that of sine wave.

                                                            square wave inverter  
A square wave inverter is very good for the use of electrical appliances like element, electric heater, pressing ion, filament bulb and electric fence, etc.
a square wave inverter is not recommendable for the use of fan and compressor because its wave form make lots of noise in a fan and may not drive the fan as fast as it use to be.
              
                                                              what makes up an inverter
there are three major pert in a simple inverter which are.
1. the inverter oscillator.
2. the inverter power transistor.
3. the inverter transformer.
                                                                     inverter oscillator.
what is an inverter oscillator?.. inverter oscillator is an electronic circuit in an inverter that convert DC to AC in a very low amps, in other word you can call it an inverter driver because the first conversion from DC to AC in an inverter take place in the inverter oscillator. the inverter oscillator output is what will determine if the inverter will be a sine wave or modify sine wave or square wave inverter. but you can filter the wave of an inverter oscillator to be smoother with an additional oscillator output filter circuit.
                                                          type of inverter oscillator. 
there are four type of inverter oscillator we will be looking at.
1. pulse modulator inverter oscillator.
2. a non pulse inverter oscillator. 
3. IC for inverter oscillator.
4. transistor inverter oscillator.   

                                              pulse modulator inverter oscillator                       
 in many inverter the oscillator is what is been use to control the inverter output and to set it at a particular voltage this is what is called pulse modulation oscillator.
a pulse modulator oscillator have a feed back ability to set the inverter output at a giving voltage, if set at 220V the inverter output will remain at 220V and if set at 120V the inverter output will remain at 120V in-respective of the load or battery drop down. a pulse modulator inverter oscillator is the best option when designing an inverter. have you ever wonder why some inverter when been loaded the output do not drop? that is the work of a pulse modulator oscillator.
                                                          non pulse inverter oscillator
a non pulse inverter oscillator is more simple to design because you will not need much component.
when you build an inverter with a non pulse inverter oscillator the inverter output will drop when you load the inverter and as the battery is discharging the inverter output will be dropping.
example if the if the battery is 12V DC and the inverter output is 240V AC when you apply a load to the inverter and the battery drop by one volt because of the load apply the inverter output will drop from 240V to 220V. how to calculate this.
divide 240 by 12 = 20 then minus 20 from 240 you will have 220, in that case each volt from the 12V DC battery is been multiply to 20V and 20 X 12 = 240.
                  
                                                       IC for inverter oscillator    
 there are lot of IC that can be use for inverter oscillator some of this IC are programmable micro cheap and some are not programmable but are pulse modulator IC and some IC are not pulse modulator but are still very good for inverter oscillator.
some pulse modulator IC are sg3524, sg3525, sg2524, 556, tl494.
there are so many non pulse width modulator IC (PWM) but we shall be looking at cd4047.
cd4047 is a very good inverter oscillator IC but it dos not have in-build (PWM) but its very strong monostable multivibrator oscillator IC.
  

                                                     Inverter power transistor
An inverter power transistor is the amplifier that amplify the AC current from the oscillator output to a higher amp  up to any capacity you want, if you want to get a reliable high capacity inverter then the DC input must be high and you must have to use a higher voltage power transistor for the inverter power.
the type of power transistor commonly use in inverter are mosfet transistor, the capacity of the inverter you want to design is what will determine the inverter DC input voltage and also the value of power mosfet you have to use.
Here are some data  for power mosfet.
Irf3205…….55V…….110A….(55 volt…..110 amps)
Irf150…….100V……….40A
Irfp150……100V………44A
Irfp250……200V………33A
Irf1404…….40V………162A
Irf1407…….75V………130A
Irf1302……..20V………180A
If you want to design a 500W power inverter of a 12V DC input the recommended power mosfet you can use is irf1404 or irf3205 or irf1302 because thy have a low input voltage and a high amps.
                                                     Inverter transformer.
The inverter transformer is what will boost the voltage from the inverter power mosfet to the set or require voltage for the inverter output. Example if you are building a 12V DC input inverter the current from the oscillator will be 12V AC and the current from the power mosfet will be 12V AC but the transformer is what will boost it voltage 12V to 220V or 120V depending on the transformer winding.