Sensorless control of switched reluctance electric machines

Abstract

A system and methodology for control of a switched reluctance electric machine comprising: a switched reluctance electric machine including a sensor generating and transmitting a sensor signal indicative of an operating characteristic; a controller operatively coupled to the switched reluctance motor and the sensor; and the controller executing a method. The method comprises: probing a selected diagnostic phase with a pulse injection process; measuring an actual operating characteristic of the switched reluctance electric machine; computing an inductance based on the actual operating characteristic and correlating the inductance with a position to formulate an estimated position; modeling the switched reluctance electric machine to formulate an observer-based estimated position; selecting at one of the estimated position, the observer-based estimated position, and a combination thereof to formulate a selected position of the switched reluctance machine; and controlling said switched reluctance machine based on said selected position and a command.

Description

[0001] This invention relates to sensorless operation of a switched reluctance electric machine.[0002] A switched reluctance motor (SRM) is a viable candidate for various motor control applications due to its rugged and robust construction. A high-performance SRM drive is possible by appropriately scheduling the commutation angles using accurate rotor position and speed information. The position information for a SRM drive is usually, obtained from a position sensor, often a shaft-mounted encoder or resolver, which adds cost and complexity to the overall drive system.[0003] Sensorless operation is a key feature required to make SRM drives industrially competitive. Sensorless operation is important for various applications due to the need for minimum package size, high reliability and low cost for electric motor driven actuators. Use of discrete position sensors adds cost and complexity to the overall drive system and generally reduces reliability especially in harsh environments. Re...

AI Technical Summary

Benefits of technology

0004] Disclosed herein is a method for sensorless control of a switched reluctance electric machine comprising: probing a selected diagnostic phase of a switched reluctance electric machine with a pulse injection process; measuring an actual operating characteristic of the switched reluctance electric machine; computing an inductance based on the actual operating characteristic and correlating the inductance with a position to formulate an estimated position; modeling the switched reluctance electric machine to formulate a modeled position; selecting at least one of the estimated position, the modeled position, or a combination thereof to formulate a selected position of the switched reluctance machine; controlling the switched reluctance machine based on the selected position and a desired command.

Problems solved by technology

The position information for a SRM drive is usually, obtained from a position sensor, often a shaft-mounted encoder or resolver, which adds cost and complexity to the overall drive system.

Use of discrete position sensors adds cost and complexity to the overall drive system and generally reduces reliability especially in harsh environments.

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