Method and device for determining the duty-cycles of PWM control signals of an inverter

摘要

An efficient method of determining the three duty-cycles of the three PWM control signals of an inverter that drives a three-phase load in SVM mode and that requires a reduced number of steps advantageously exploits the fact that the three duty-cycles are modulated, in function of the angle ³ of the phasor that represents the triplet of voltages to be applied, according to modulating signals that may be reconstructed from only two waveforms using reflection and reversal operations. By storing these two waveforms in two look-up tables, it is possible to reconstruct the modulating signals for each value of the angle ³, with a single memory access and eventually an addition.