As part of a Swiss research project, a motor system using silicon carbide (SiC) MOSFET-based Variable Speed Drive was evaluated against a conventional system with insulated-gate bipolar transistor (IGBT) technology. Energy loss measurements from both systems were used to estimate the potential savings if all speed-controlled pump drive systems worldwide were converted to SiC technology. The results point to a global annual savings potential of 17 – 25 TWh.

Key findings from the efficiency comparison:

1. Higher efficiency at all loads: Replacing IGBT-based Variable Speed Drives with SiC MOSFETs increased system efficiency by up to 10 percentage points at partial load and by about 1 percentage point at nominal load.
2. Switching frequency has limited impact: Raising the switching frequency above the standard 8 kHz did not significantly reduce overall losses, with or without a sine-wave motor filter.
3. Motor-side filtering enhances performance: Using a motor-side filter with low-loss core material further improved efficiency. In combination with SiC Variable Speed Drives, this setup reduced total system losses to a minimum.
4. Importance of sine-wave filters: Removing the sine-wave filter led to a disproportionate increase in motor losses, caused by unfiltered current ripple.

Conclusion: Transitioning from IGBT to SiC-based Variable Speed Drives in pump systems offers a clear path to substantial energy savings, particularly in applications with varying loads.

For more details, download the full report.