Hybrid ASD Comparison With Conventional - Significant Efficiency Improvements are Still Available

Abstract

High speed pump and compressor applications can frequently gain significant performance improvements when operated via an adjustable speed drive (ASD). By utilizing a fixed speed motor to provide a portion of the rated power (for example, 85%), two small servo motors (combined rating 15%) each connected to an ASD and an epicyclic gearbox, a high performance Hybrid ASD solution can show significant additional benefits beyond the conventional ASD approach. A detailed comparison between this hybrid system and a conventional system utilizing a fully rated ASD and a parallel offset gearbox based on a nominal compressor load of 10.9MW, 10,000rpm is presented in detail. Most notably, these benefits include an efficiency improvement in excess of two percentage points.