A resonant-commutated-link variable-frequency converter

A novel dc-link converter utilizing resonant commutation is presented. Since resonant commutation is accomplished, converter switches are thyristors (SCR's) with lower costs than forced commutated devices. Focus is on the variable-frequency operation of the converter, with potential application in variable-frequency custom power delivery or adjustable-speed motor drives. The converter operates with greater stored energy in the dc link, thus offering current holdup capabilities during a contingency which cannot be attained with a conventional resonant dc-link converter and achieves minimum switching losses without increased conduction losses. Harmonic elimination is achieved by employing sinusoidal pulsewidth modulation (SPWM) control of the converter. Simulation results and experimental validation of the resonant commutation of a low-voltage and low-power laboratory model are discussed. Work in progress and the scope of further work are discussed. Index Terms - Modulation index control, resonant commutation, resonant link converter, switching losses.