Multi-modular current-source SPWM converters for superconducting magnetic energy storage system

The authors point out the advantages of using multiple modules of the current-source, sinusoidal pulse-width-modulation (SPWM), three-phase, six-valve converters as the power conditioner for a superconducting magnetic energy storage system. A high degree of controllability is obtained by using dynamic SPWM trilogic as the operating strategy. Very low switching losses are assured by using two carrier triangles per modulating cycle. By parallel connection of coverter modules and by phase shifting the triangle carriers, the following are the gains: increasing the current capacity to the level required by the superconducting magnet, reducing conduction losses, meeting harmonic standards, without the need for an expensive filter, by harmonic cancellation, and achieving a high frequency bandwidth