In this project we design an Inverter to convert 12V DC power source to 230V AC power. This system consist 3 main stages such as oscillator, switching circuit and step up transformer stage. In oscillator we use 4047 CMOS astable multivibrator to generate nearly 60Hz oscillation.
In a given configuration,
f = 1/(4.4C2(R1+R2))
f = 1/(4.4×(0.1/106)((3.3+33)×103)))
f = 62.609 Hz
In a switching stage we use 2SD400 NPN transistors and IRFZ44 N-channel FETs. For the step-up transformer it is recommended to use 12V-0-12V : 230V – 5A transformer.
When constructing the circuit it is highly advisable to apply good heat sinks to both Q1 and Q2. If you are plan to use single heat sink to both Q1 and Q2 it is required to place good insulator between the transistors and the heat sink.
During the field test we use 12V - 7Ah sealed lead acid battery (which was commonly used in general UPS) with this system and constructed prototype deliver 238V AC in no-load.
To get the complete circuit diagram and Eagle PCB design please check the http://elect.wikispaces.com.