Make True Sin Inverter ?

true-sinüs inverterler

I have proplems when write the program to make a true sin Inverter .When the Load is R the output is good .But when the load is nonlinear ( as a full wave rectifier ) ,the output isn't sin wave .I use the PI control for output voltage .I think I need use the PI for the output current but I don't know how do it .I need a source code or some designs .Hepl me! Thanks.

sin inverter

please post your circuit

true sin inverter

use XR2206 Function Generator for sine way generation.....

inverter with xr2206

hoang_quy said:

I have proplems when write the program to make a true sin Inverter .When the Load is R the output is good .But when the load is nonlinear ( as a full wave rectifier ) ,the output isn't sin wave .I use the PI control for output voltage .I think I need use the PI for the output current but I don't know how do it .I need a source code or some designs .Hepl me! Thanks.

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If you want good voltage shape on output in unlinear load, you must have voltage source output with very low impedance (not current limited and huger current resources on maximal voltage peak) - PU-control if i thinking your 'PI' right above. For 'P' limit, you cannot using simple 'P=UI' calculate on peak current and peak voltage, you must intergrate over full period with continius multiplication as analog multipler circurits or high sampling rate digital system (>250 sampel/period) to calculate 'Watts per period' if you want usable 'Watt' power limit on UPS on not so nice unliniar load.

In case of unlinear load you can not make sinusial current and voltage in same time, you must choice between sinusial current and distord voltage shape or sinusial voltage and distord current shape -> unlinear load as rectifier give high crest factor loads, ie. draw high current peak in very small time on voltage top (10% of sinus voltage shape and up to ten time higher current compare to averange 'P=UI' load over time) and zero current rest of time - and you must make inverter output can give ten time more current in peak and maximum voltage compare you designed 'P=IU' Watt capacity.


Peak current drawing from rectifier in all switched power supplys over world (including millions of power save flourecent ligth with electronic ballast) is a big problem in power-grid world, and try measure voltage from socket in wall with oscilloscope and you see more or less hard distorded 230/115 AC Voltage shape - same effect you see on your inverter. Your sinus inverter and power grid manager have same problem... ;-)