The Effect of Amplitude Modulation Index and Frequency Modulation Index on Total Harmonic Distortion in 1-Phase Inverter

One of the problems that often arise in the conversion process using an inverter is the existence of Total Harmonic Distortion (THD). Harmonics is a symptom of sinusoidal wave formation whose frequency is a multiple of fundamental frequency. Harmonics will cause interference to the system to damage to electrical devices. This paper discusses the effect of modulation index value amplitude (Ma) and frequency modulation index (Mf) of the value of THD before using the filter. The test was performed using a 1 phase inverter with input variation of the amplitude modulation index and the frequency that was set using PSIM software. The 16 ATMega microcontroller is used as a pulse width modulation (PWM) signal generator. Simulations using a 6 variations value Ma, i.e.: 0.4, 0.6, 0.8 1.0, 1.2, and 1.4, as well as 10 variations of the value of Mf, namely 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100. Based measurement, for Mf are the same, the greater the value of Ma, then the value of THD tends to decrease. Meanwhile, for the same Ma, the greater the value of Mf, then the value of THD tends to decrease