摘要:

The paper examines the optimal efficiency excitation of a variable-reluctance motor (VRM) drive operating at constant speed. The drive comprises a motor, an inverter, an excitation and a control strategy. The excitation refers to a prescribed relationship between the phase currents and rotor position that results in the desired drive behaviour. The excitation is considered from an integrated viewpoint such that overall drive efficiency is maximised for a given torque and speed. An algorithm for the determination of optimal excitation is presented. The algorithm is based on the determination of excitation that nominally meets the drive torque-speed requirement, followed by optimisation of this excitation to improve efficiency. Other performance criteria, such as torque ripple or acoustic noise, could be considered in a similar manner, with appropriate models. The paper applies the algorithm to high-power (60 kW) VRM drive. The results of the optimisation indicate the importance of considering inverted losses when performing the optimization. Inverter losses are shown to be comparable to motor losses, imparting significant influence on the excitation design. The stability implications of the optimal-efficiency excitation are discussed, including the necessity for closed loop control. In addition, the experimental VRM drive design is critically reviewed based on the breakdown of inverter and motor losses. Allowable excitation parameter variations and the dependence of the optimal excitation on load torque are also discussed.

DOI:10.1049/ip-b.1991.0001

出版商:IEE    

年代:1991

数据来源: IET

摘要:

It is shown that rectification and reinjection of the DC ripple can double the number of pulses of parallel connected AC/DC convertors with interphase reactors. Theoretical and experimental evidence is provided to demonstrate that the combined use of phase-shifting and DC ripple reinjection techniques effectively quadruples the pulse number of bridge rectifiers and inverters. Although the analysis is general, the results displayed relate to the conversion of a conventional 12-pulse double bridge for use as a 24-pulse configuration.

DOI:10.1049/ip-b.1991.0002

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A method of reducing the torsional vibration of a motor using a dynamic absorber has been studied. The vibration characteristics of a motor-mounted dynamic absorber have been analysed. Theoretical and experimental investigations show that the absorber is highly effective, even for the reduction of low-amplitude torsional vibrations where viscous dampers do not function as well. Furthermore, it is shown that the response of the control system does not deteriorate, even when an absorber is applied to the 2-phase servomotor of a servo system. Therefore the twice-line-frequency torsional vibration of a 2-phase servomotor, caused by an unbalanced voltage supply, can be reduced by the application of the dynamic absorber.

DOI:10.1049/ip-b.1991.0003

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper describes a novel method of rotor-position sensing of permanent-magnet machines, which requires no encoder nor any modification to conventional machines. The machine is electronically commutated, by virtue of position sensing, achieved through measuring the modulation in the inverter carrier frequency component, caused by the positional variation in motor winding impedance. A closed-loop speed control system drives the motor with precision and at maximum efficiency for a wide range of load and speed.

DOI:10.1049/ip-b.1991.0004

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A new approach for decomposing voltage, current and power in power systems is presented. According to different situations, the hierarchical decomposition can be used. Whenuandihave the same harmonic spectra, Czarnecki's concepts are applied; whenuandihave different harmonic spectra, Slonim and Wyk's concepts are considered.

DOI:10.1049/ip-b.1991.0005

出版商:IEE    

年代:1991

数据来源: IET