Restart Strategy for Synchronous Reluctance Machine Driving a High Inertia Load

In many industrial settings, momentary power disruptions commonly occur, resulting in tripping of large electric machines, which then have to be brought to zero speed before the machine can be restarted. This approach can result in frequent interruptions in an industrial process, which can have negative effects on productivity. A more practical control implementation would restart the machine back to the original speed as soon as power is restored, not having to wait for the machine to be at a standstill. This concept is known as flying restart. In this paper we propose an approach to implement the universal restart for SynRM (Synchronous Reluctance Machine) through a simple identification algorithm which determines the speed and position of the machine so that the correct voltage vector can be applied and thus minimize the inrush current during the restart. The novelty of the proposed method is that its implementation only requires nameplate machine parameters and needs no machine-specific tuning, making the approach suitable for implementation with both high-inertia vector and scalar-controlled SynRM.