Thomas A. Nondahl

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This paper provides and analyzes a simple, robust, and universal model for rotor position estimation for synchronous machines. The rotor position is estimated using an equivalent electromotive force (EMF) model of a synchronous machine or, alternately, using a sliding-mode observer (SMO) based on the equivalent EMF model. The SMO provides fast convergence(More)
This paper addresses the position error issue existing in sensorless IPM motor drives using the high frequency injection (HFI) method. A simple-to-design on-line compensation method is proposed based upon filter group delay theory, which substantially minimizes the error between the estimated position and the actual position caused by filters in a(More)
This paper provides a simple, robust, and universal position observer for position sensorless control of synchronous machines. The observer is designed using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model. The sliding mode observer provides fast convergence and low(More)
Society Leadership Changes A new Executive Board takes over leadership of the Society effective 1 January 2005. The Executive Board has day-to-day management responsibility for the Society and consists of four elected officers, the four operating department chairs, the chairs of the four staff departments, and nine members-at-large. Newly elected officers(More)
In recent years there has been increasing acceptance of position sensorless control in industrial products. This paper discusses the implementation and performance of a position sensorless permanent magnet synchronous motor (PMSM) control over the full speed range in a PMSM drive. Experimental results with a commercial drive which utilizes a sensorless(More)
This paper proposes a general approach to designing a stability control for open-loop operation that can be used for either induction motor, permanent magnet synchronous motor, or any other motor drives. A speed or frequency set point is adjusted by a frequency compensation value to provide the stability control to mitigate hunting or motor stoppage. The(More)
This paper proposes a position sensorless control scheme for an induction and permanent magnetic motor drive with output filter and transformer. The proposed method provides sufficient starting torque with controlled drive/motor current. In addition, transformer saturation is addressed. The sensorless starting scheme presented in this paper has been(More)
This paper proposes a simple MATLAB/ SIMULINK model of a three-phase, three-legged, saturated transformer. A fictitious delta winding is added to three single-phase saturable transformers. The proposed model is simple and fairly accurate to model the nonlinear characteristics of a saturable three-legged transformer including mutual coupling.
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