RANCANG BANGUN PENYEARAH TERKENDALI TIGA FASA BERBASIS MIKROKONTROLER

Abstract

This reseach was based on many usages of power electronics in the processes of electrical conversion. DC voltage source is very important in daily activities. DC voltage needed is changing sometimes depending on load requirement. Based on that, it was build a three phase half wave controlled rectifier using microcontroller. Microcontroller ATmega 8535 was used as PWM signal control and the PWM signal was processed in microcontroller ATmega 16 based on ADC data from potentiometer to measure firing angle of the thyristor. This equipment started to work if zero crossing detector circuit detected sinusoidal AC 220V wave while passing through the zero point from phase R, S, T. Zero crossing was reference which is used as starting of giving suspended time delay to microcontroller for triggering thyristor. The thyristor used SCR BT151. Firing signal was gained from microcontroller output, then it was passed to optoisolator MOC 3020 circuit. The firing angle can be set is about 0⁰ up to 180⁰ with potentiometer. This three phase half wave controlled rectifier had been tested to produce variation DC voltages based on thyristor firing angel. This rectifier worked in 0⁰ – 180⁰ and voltage variation produced was about 0-140Vdc. Bigger thyristor firing angel, smaller output voltage produced. This rectifier had worked well even though the output voltage was not same as theory.

Kata Kunci:  ATmega8535, ATmega16, PWM, thyristor, zero crossing detector.