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feed back current sensing for pic microcontroller

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nouman_rafi

nouman_rafi

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I make open looop PWM sine wave single phase inverter for p.v cell.Now i want to make feedback current sensing circuit to take sample of curent.By the help of this sample i change duty cycle automatically.controller that i can use is pic 18 series.my inverter is 100 watt.
 

So you want to measure alternating current, right? There are two ways. One is to use a shunt resistor, and the other is to use a transformer.

First approach has advantage of being simple and cheap, but also contributes power loss in circuit. Resistor can be really small (like 0.2R or something). Then you amplify and measure the voltage drop across shunt resistor.

Transformer approach uses a small tranfnormer with appropriate winding ratio where load current flows through primary and voltage is measured in secondary winding. This involves (probably) winding a custom impulse transformer, which is pain in the ass.
 

11112011117.jpg

you can find a example here for Shunt resistor What is a Shunt - Electric Circuit,
however i tried to read the current in safe way by using CT at ratio of 1:200 turns, it work with PIC 16F877 ,
 

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