摘要:

A modular DC–DC convertor for high-output voltage applications is presented. The proposed convertor consists of DC–DC modules whose inputs are connected in parallel and the outputs in series, with a control scheme that ensures input current sharing among the modules and regulated output voltage. Moreover, it utilises single feedback sensing that achieves almost equal output voltage sharing among the modules.

DOI:10.1049/ip-b.1993.0012

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Resonant link inverter configurations have been proposed as a means of obtaining significantly lower switching losses, thereby allowing operating frequencies and switch power ratings to be raised. In the paper, resonant link topologies are analysed by means of time-domain simulation, and the frequency spectrum typical of a resonant link inverter is compared with one typical of a hard-switched inverter. The resonant link system results in an increase in circuit complexity, and the frequency spectrum is limited by the need to employ integral pulse-modulation techniques.

DOI:10.1049/ip-b.1993.0013

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A new and efficient approach for the analysis of power electronic circuits using the modified nodal formulation of circuit equations is presented. The method is well suited for the development of dedicated simulation software for power electronic systems. Semiconductor switches are modelled as binary inductors, as a very low value of inductance (determined by the rating of the semiconductor) during conduction, and infinite value of inductance otherwise. The system matrix is partitioned in such a manner as to permit efficient handling of switch status. Changes in topology are taken into consideration by the least amount of computation. The method can be easily adapted to incorporate control circuits and machine representations. The backward Euler method of integration is used for the solution of equations to ensure convergence. Examples of regulator and inverter circuits are solved using the new approach and results are included.

DOI:10.1049/ip-b.1993.0014

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper introduces the axially laminated anisotropic (ALA) rotor reluctance synchronous machine as a brushless high-performance generator. A new theory for steadystate performance analysis and determination of maximum power-conversion capability of reluctance generators is presented. The high efficiency, high power factor, and high power density of the ALA-rotor reluctance generator are demonstrated through load tests on a laboratory model obtained from a 1.5 kW, 2-pole induction machine whose rotor was replaced by a single lamination/insulation-layer ALA rotor built for demonstration purposes. Unusually high values ofLd/LLratio have been measured (Ld/Lq> 16). The reluctance generator should be ideal as a DC-output brushless generator, with power electronics for voltage control.

DOI:10.1049/ip-b.1993.0015

出版商:IEE    

年代:1993

数据来源: IET

摘要:

An original electric machine is described which has a single stator and two rotors, each core being of a disc geometry, with the stator sandwiched between the two rotors. The rotors carry squirrel cage windings, and are mounted on individual, independent shafts driving two wheels of an electric vehicle. The torque generated by each rotor depends on the slip of each rotor and the dimensions of the cores, particularly the stator yoke depth which controls the magnitude of any differential flux in the two sections of the machine. An analytical model of the machine is developed, based on a travelling wave model and taking into account the harmonics, travelling at synchronous speed, which are produced by saturation in the various parts of the cores. Leakage fluxes are accounted for, and are divided into fluxes which do, and do not, contribute towards saturation in the machine. Laboratory results are compared with those predicted by the model. Systematic differences are evident between these results and explanations are offered to account for them.

DOI:10.1049/ip-b.1993.0016

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The static and dynamic characteristics of a practicable step-up nine-switch matrix convertor under the control strategy proposed by Venturini are analysed fully by the recently presented circuit DQ transformation technique and signal flow graphs. The step-up nine-switch matrix convertor consists of nonideal voltage and current sources, such as occur in practical inductance and capacitance filters. The energy storage elements of inductors and capacitors are not simplified into ideal current and voltage sources, as in most previous works, so that the dynamic behaviour of the convertor can be explored. Several static and dynamic features of the convertor, such as steadystate input/output voltage gain, input power factor and transient response, are predicted analytically and verified by computer simulations. The signal flow graph is adopted to solve the complex fourth-order equivalent convertor and thus the nine-switch matrix convertor is analysed fully in explicit form. It is found that the voltage gain and input displacement angle cannot be independently controllable, unlike the ideal nine-switch matrix convertor case; however they are controllable to a certain extent by a properly selected switch modulation function. The paper compares computer simulation results with those obtained by analytic technique. The authors expect to report on practical circuit work in due course.

DOI:10.1049/ip-b.1993.0017

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The feasibility of using solid-state technology for certain medium voltage applications was investigated. The application considered was a 7.2 kV contactor unit which despite a number of design problems proved to be technically successful. The solid-state approach, despite its relative complexity and a certain cost penalty, offers the user certain advantages for this type of application. For the moment, however, medium voltage applications are limited by the available power semiconductor performance.

DOI:10.1049/ip-b.1993.0018

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper describes techniques for the design, construction and analysis of multielement transformers based on toroidal core transformer elements. It is shown that the multielement approach lends itself most readily to high frequency, low voltage DC–DC convertors. The design techniques for one multielement transformer are described in detail. Results for this, and a further three transformers, were evaluated in conventional rectangular wave convertors at 500 kHz. We have shown that the multielement transformer is a cheap, efficient design, which is ideally suited to this application. Its low leakage inductance means that voltage spikes produced at the turnoff transitions contain little energy and can be controlled by a simple zener diode clamp.

DOI:10.1049/ip-b.1993.0019

出版商:IEE    

年代:1993

数据来源: IET