Rotor Position information is essential in the operation of the Switched Reluctance Motor (SRM) for properly controlling its phase currents. This thesis uses Field Programmable Gate Array (FPGA) technology to implement a method to estimate the SRMs rotor position using the inverse inductance value of the SRMs phases. The estimated rotor position is given as input to the Commutator circuit, also implemented in the FPGA, to determine when torque-producing currents should be input in the SRM phase windings. The Estimator and Commutator design is coded using Verilog HDL and is simulated using Xilinx tools. This circuit is implemented on a Xilinx Virtex XCV800 FPGA system. The experimentally generated output is validated by comparing it with simulation results from a Simulink model of the Estimator. The performance of the FPGA based SRM rotor position estimator in terms of calculation time is compared to a digital signal processor (DSP) implementation of the same position estimator algorithm. It is found that the FPGA rotor position Estimator with a 5MHz clock can update its rotor position estimate every 7s compared to an update time of 50s for a TMS320C6701-150 DSP implementation using a commercial DSP board. This is a greater than 7 to one reduction in the update time.

This thesis deals with the modelling, simulation and control of Permanent Magnet Synchronous Machines (PMSM) used specially in electric and hybrid vehicles. With the availability of fast semiconductor switches and high speed processors, Vector controlled drives are gaining popularity. One disadvantage of this type of control however, is the need for high cost, high resolution sensors (encoders) for determining the rotor position. Position sensorless schemes have evolved over a decade and this thesis addresses this issue. Two schemes have been proposed for the elimination of encoders in vector controlled drives. One is a semi-sensored scheme wherein a combination of low cost hall sensors and a digital position estimator gives the position information. In the second scheme, a reduced order observer called Luenbuerger observer has been used to estimate speed and rotor angle. The problem of finding rotor angle at standstill has also been dealt with. This thesis also discusses the difference in simulating a BLDC (Brushless DC) and PMSM machine. An experimental set-up consisting of MOSFET inverter and TMS320LF2407 DSP based digital controller was developed in the laboratory to implement the control algorithms. Two PMSM machines were procured from a two-wheeler manufacturer to set up the rig. Simulations were done in MATLAB/ Simulink (Off-line) and Xilinx XC3S400 (in real-time) to verify the concepts. Simulation and experimental results are finally compared.

The development of an add-on sensorless position estimator for a 4.8 m Linear Switched Reluctance Machine (LSRM) with minimal modifications to the transducer-based controller is investigated for the first time in this study. LSRMs require position feedback for closed-loop control but present a low cost, high energy efficiency alternative for linear actuation due to their rugged construction and single-sided excitation. Mechanical position transducers mounted on the vehicle are expensive and can impact reliability. The use of a sensorless position estimator removes all electronics from the passive vehicle, resulting in considerable reductions in cost, maintenance, and mechanical complexity. This study examines the use of an add-on processor and data acquisition system for sensorless position estimation. An approach exploiting the active phase windings is used to preserve the normal operation of the transducer-based DSP controller with the goal of limiting reductions in high performance features such as force ripple reduction and velocity control [3]. The estimator system is retrofit to the transducer-based DSP controller by mimicking the output of a mechanical position sensor by emulating a Quadrature encoder. The feasibility and design issues for an add-on or retrofit position estimator are investigated. Although sensorless schemes for rotary Switched Reluctance Machines (SRMs) have been studied in detail, the problem of sensorless implementations for LSRMs has not been addressed. Experimental validation of the proposed sensorless estimation scheme is attempted, but closed-loop operation is not achieved successfully due to air gap fluctuations. In depth analysis of the sources and propagation of error is presented. / Master of Science