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This paper considers the operation and control of a brushless ac prototype embedded aircraft generator that has been designed for use as an alternative to the emergency run air turbine. To meet the wide operating speed requirements, the generator utilizes a hybrid rotor construction comprising permanent magnet and variable reluctance sections. The constant current source characteristics of the design are exploited to derive the phase information required by the ac vector controller, thus avoiding the use of a shaft-mounted rotor position sensor. The methodology behind the controller operation is presented together with test results taken from a prototype generator system, and this is contrast with the results taken from the conventionally controlled machine with resolver position feedback. Index Terms--Embedded aircraft generation, hybrid permanent-magnet (PM)/variable reluctance machines, power factor control, sensorless control.

This paper presents recent research into the use of an embedded generation system as an alternative to the emergency ram air turbine on aircraft, the proposal being to utilize the windmill effect of the low-pressure turbine of the main aircraft engine for emergency power generation. A novel topology of a high specific output ac permanent-magnet generator is described that has been designed to be driven directly from the low-pressure turbine via an integral fixed-ratio gearbox, the requirement being to generate a regulated 270-V dc 0-20-kW emergency supply over a 12 : 1 3000-36 000-r/min generator shaft speed range. The methodologies behind the machine design and operation are described together with test results taken from a prototype generator system. Index Terms--Embedded aircraft generation, high-speed permanent-magnet (PM) generators, hybrid PM/variable-reluctance (VR) machines.

The present paper describes an angle and speed estimation algorithm suitable for the control of a wound-field synchronous starter/generator (S/G) without position sensors for aircraft engine starting applications. The proposed control strategy is based on the injection of a high-frequency voltage signal and the subsequent demodulation of the resulting high-frequency stator current components. The coupling due to high-speed operation that degrades the estimation accuracy of similar algorithms based on signal injection is taken into account. Modeling of the machine response to a high-frequency voltage signal injected into the estimated d-axis is presented, also considering the influence of damping circuits both on the d- and q-axis. Local asymptotic stability of the proposed observer is also demonstrated. Through extensive experimental results, the proposed control technique is shown capable of guaranteeing full-torque sensorless operation at zero speed and sustained operation up to engine ignition speed. [ABSTRACT FROM AUTHOR]

Studies the fault-tolerant operation of multipole single-phase switched reluctance generators (SRG). Description of the multipole single-phase SRG; Analysis of the SRG performance; Application of two-dimensional finite-element analysis and static torque measurement; Operation of disconnecting faulty bank.

Studies the operation of the multipole single-phase switched reluctance generator (SRG) under faults. Characteristics of SRG; Description of output power under coil faults with constant currents; Investigation of the SRG under the faults.