Motor starter for synchronous machine

Abstract

Embodiments of the invention relate to a motor starter for a synchronous machine. Systems, methods, techniques and apparatuses of motor starters are disclosed. One exemplary embodiment is a synchronous machine including a plurality of stator phase windings, a rotor, a motor starter, and a controller. The motor starter includes a plurality of wye semiconductor switches and a plurality of delta semiconductor switches. The controller is structured to operate the plurality of wye semiconductor switches and the plurality of delta semiconductor switches so as to couple the plurality of stator phasewindings in a delta configuration while an angular speed of the rotor is less than a synchronous speed, and structured to operate the plurality of wye semiconductor switches and the plurality of deltasemiconductor switches so as to couple the plurality of stator phase windings in a wye configuration in response to the angular speed of the rotor being equal to the synchronous speed.

Description

technical field [0001] The present disclosure generally relates to electric motor starters. Background technique [0002] A synchronous motor undergoes a starting operation to achieve synchronous speed. For synchronous machines directly connected to the utility grid, the synchronous speed of the synchronous machine is based on the frequency of the power from the grid and the number of poles of the rotor and stator. During start-up operation, the inrush current magnitude tends to spike. Where a synchronous motor is connected to the mains without an intermediate variable frequency drive, a motor starter is often used to limit the inrush current. [0003] Synchronous motors can be used to rotate loads with a high moment of inertia, such as fan centrifuges or conveyors. Certain synchronous motors cannot run at speeds synchronous with high moment of inertia loads that can be rotated by similarly rated induction motors. This drawback is due to the inability to bring high momen...

AI Technical Summary

Problems solved by technology

Conventional motor starters do not develop enough torque to pull the motor into synchronous operation

[0004] Existing motor starting operations have many disadvantages and disadvantages

There are still unmet needs which include reducing hardware complexity and reducing machine power consumption

For example, synchronous motors spinning high moment of inertia loads require expensive variable frequency drives that generate switching power losses during operation

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