Generalized Modulation Technique for Current Source Converters

Abstract

The pulse width modulation (PWM) schemes are receiving increased attention for their ability to control the harmonic content of output. Sinusoidal PWM and space vector PWM are widely used for power converters. The comprehensive relation between the two methods provides a platform to develop new PWM modulators. In this paper a simple but superior carrier based PWM technique with reduced computations and improved modulation index is proposed for current source rectifiers and inverters. The proposed technique extracts the duty cycle information from the reference currents and the input current using simple logic circuit which directly generates the firing pulses for the switches. The proposed new carrier based PWM scheme offers an increased modulation index compared with conventional sinusoidal PWM technique. The proposed algorithm can also be extended for current source multilevel inverters (CSMLI). The algorithm is validated by simulation using MATLAB / SIMULINK