EFFECT OF SUPPLY VOLTAGE HARMONICS ON THE INPUT CURRENT OF SINGLE-PHASE DIODE BRIDGE RECTIFIER LOADS

This paper describes the effect of supply voltage harmonics on the response of single-phase capacitor filtered diode bridge rectifier loads. A complete analytical model for calculating the current harmonics of these loads, when energized by nonsinusoidal supply voltages, is presented. The model is then used to investigate the effect of supply voltage harmonics on current harmonics. The key findings of the paper are as follows: 1. The phase angles of supply voltage harmonics determine whether or not these harmonics increase or decrease current distortion. In general, a peaked voltage wave increases input current distortion, whereas a flattened wave has the opposite affect, Because of this complex relationship, voltage crest factor is a much better predictor of total harmonic current distortion (THDI) than is total harmonic voltage distortion (THDV). 2. The current harmonics created by these loads produce voltage harmonics that tend to have a partial self-compensating effect on the current harmonics.