Implementation and Evaluation of a Full-Order Observer for a Synchronous Reluctance Motor
Sensorless control of the synchronous reluctance motor has been a topic of research for more than a
decade, producing several successful methods to accomplish this goal. However, a technique that has been overlooked is the full-order nonlinear observer, which is essentially a software model of the motor driven by measurements from the actual motor.
Presented in this thesis is the design, implementation, and experimental testing of a full-order observer-based sensorless control technique which requires only the phase current and voltage measurements that are typically available in standard three-phase inverters.
A technique is also presented for calculating a table of observer feedback gains parameterized only by the steady-state motor speed. This allows a gain-scheduling observer to be implemented which, as shown using experiments, improves the transient response of the observer over a wide speed range.
The sensorless controller consists of a full-order nonlinear observer coupled with an input-output
linearization speed controller. The resulting controller was implemented in Simulink and executed on a dSPACE DS1103 real-time DSP board using the Real-Time Workshop extension to Simulink. A custom built three-phase IGBT inverter was used to interface the DSP to a 100 watt synchronous reluctance motor for laboratory testing.
The resulting sensorless controller was able to successfully track a varying speed reference from
150 rpm to 1800 rpm with a tracking error under 5% for most of the speed range. At the lowest
speeds, the tracking error begins to increase but the observer remains stable down to 150 rpm.
Advisor:Taylor, David; Harley, Ronald; Habetler, Thomas
School:Georgia Institute of Technology
School Location:USA - Georgia
Source Type:Master's Thesis
Keywords:electrical and computer engineering
Date of Publication:04/12/2004