Design of a PWM current source rectifier for high power induction melting applications

PWM current source converters (CSCs) can directly replace traditional thyristor rectifiers in many industrial applications to improve power quality significantly. In this work, a design process for PWM current source rectifiers in the range of 1-10 MVA is developed. Different PWM techniques for CSCs are reviewed in the light of semiconductor losses and harmonic distortion of the modulated current. A design procedure for the AC-filter (LC-filter) is proposed that identifies filter designs that comply to emission limits for harmonic currents as well as thermal limits of the semiconductors. The design procedure is verified by detailed simulations. Results of a real-world case study are presented.