Suresh Gopalakrishnan

Four-Quadrant Pulse Injection and Sliding-Mode-Observer-Based Sensorless Operation of a Switched Reluctance Machine Over Entire Speed Range Including Zero Speed

The objective of this paper is to present a sensorless position estimation technique for switched reluctance machines (SRM) operating in constant dynamic mode over a wide speed range including zero speed. The technique combines two different methods to deliver high resolution position information over the wide speed range. At zero and low speeds, a voltage pulse injection method is used to estimate the rotor position in all four quadrants. For higher speeds, a sliding mode observer (SMO) based algorithm is used and combined to work with the low speed algorithm. Experimental results demonstrate the effectiveness of this new combined technique that has four-quadrant operation capability.

Fault Tolerant Permanent Magnet Motor Drive Topologies for Automotive X-By-Wire Systems

Future automobiles will be equipped with by-wire systems to improve reliability, safety and performance. The fault tolerant capability of these systems is crucial due to their safety critical nature. Three fault tolerant inverter topologies for permanent magnet brushless dc motor drives suitable for automotive x-by-wire systems are analyzed. A figure of merit taking into account both cost and post-fault performance is developed for these drives. Simulation results of the two most promising topologies for various inverter faults are presented. The drive topology with the highest post-fault performance and cost effectiveness is built and evaluated experimentally.

A hybrid sensorless SRM drive with eight- and six-switch converter topologies

This paper presents a hybrid sensorless controller used with both the classical eight-switch converter and a reduced six-switch converter topology for switched reluctance motor (SRM) drives. The hybrid sensorless scheme consists of a sliding mode observer (SMO)-based position sensorless approach for high speeds along with a low-resolution discrete sensor for low speeds and standstill. The hybrid position estimation switches between the SMO and the low-resolution sensor according to the speed sign and the position error difference between the SMO and the low-resolution sensor. The experimental results show the robustness of this hybrid low-cost control approach with the two converter topologies.