Principle of Inverter

Inverter

• It is a apparatus or device which converts constant DC voltage into variable voltage, variable frequency AC supply.

Principle

• The basic circuit for voltage driven Inverter is shown in the figure A.
•  The DC supply is given to the primary winding of the transformer. 
• There are two semiconductor switches S1 and S2 in which switching is done by astable multivibrator at selected frequency. 
• When the switch S1 is kept on, the current flows through transformer upper primary winding resulting the flux generates in the core and induced emf in it.

• Similarly when switch S2 is kept on, the current flows through lower part of the transformer primary winding resulting the flux generates in the reverse direction. 
• This will result in emf induced in the reverse direction. The switching of switch S1 and S2 are done alternately. 
• There is a transistor, SCR, MOSFET, IGBT or GTO used as a semiconductor device. 
• The saturation voltage drop of these devices is low therefore it is neglected. As the input voltage is DC, the output is square wave.

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