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EPE Journal Volume 12-3 - Papers
- Eddy Current Losses: a Theoretical Discussion of Dowell's Layer Copper Factor
- Extension of the Park's Transformation Applied to Non-Sinusoidal Saturated Synchronous Motors
- A Multilevel Voltage Space Phasor Generation for an Open-End Winding Induction Motor Drive Using a Dual-Inverter Scheme with Assymetrical DC-Link Voltages
- Analysis and Experimental Results of Squarewave Current Shaping for Reducing Commutation Torque in SPM Motors
- Feeding the Grid from Regenerative Sources, the Way to a Sustainable Energy Supply?
- EMC Compliant Harmonic and Reactive Power Compensation Using Passive Filter Cascaded with Shunt Active Filter
EPE Journal Volume 12-3 - Editorial
By G. Maggetto
The Editorial of the EPE Journal Volume 12 N°3, "The Sixth EC Framework Programme, The European Research Area - Unique Challenges for the European Power Electronics Community", written by Prof. Gaston Maggetto, Chairman of the Editorial Board of the EPE Journal.
EPE Journal Volume 12-3 - Papers
By F. Robert
In ID analytical models aimed at calculating eddy current losses in magnetic devices subject to high-frequency effects, the "layer copper factor" is classically used to take layers composed of several conductors into account. In this paper, we discuss the theoretical base of this factor, showing that the equations used in Dowell's basic paper are inconsistent with Ampere's law. as a conclusion, the layer copper factor is re-interpreted as a true empirical correcting factor which can be used to model several 2D effects of the fields inside the windings.
By G. Sturtzer; D. Flieller; J.-P. Louis
This paper presents an extension of the Park transformation that takes into account the magnetic circuit saturation. This transformation applies to variable reluctance synchronous motors, excited or not. This method follows from the evolution of the operating point with constant torque and minimum copper losses in the Concordia frame.
By V. T. Somasekhar; K. Gopakumar; E. G. Shivakumar; A. Pittet
An open-end winding induction motor drive fed from two inverters with different DC-link voltages is proposed in this paper. A total of 64 voltage space phasor combinations are possible in this scheme, as each inverter is capable of producing 8-voltage space phasors independently of the other. The proposed scheme produces 37 voltage space phasor locations while a 3-level inverter produces only 18 voltage space phasor locations. In the proposed scheme, the neutral connection of the induction motor is removed (open-end winding) and is fed from both the ends. Two 2-level inverters with isolated DC-link voltages of 2/3 Vdc and 1/3 Vdc are used for driving the motor, where Vdc denotes the DC-link voltage of an equivalent conventional (single-inverter) scheme. A combination of two 2-level inverters with 2/3 Vdc and 1/3 Vdc DC-link voltages produces a total of 64 voltage space phasor combinations in 37 space phasor locations. The voltage space phasor locations can be associated with three regions according to the speed range. In the lower speed range, while being in the PWM mode of operation, the phase voltage exhibits a six-step envelope (similar to the conventional scheme) and in the middle range the motor phase voltage, still being in the PWM mode of operation, shows a 12-step envelope. In the higher speed range (including over modulation) the motor phase voltage has an 18- step envelope. A simple and elegant space phasor based PWM scheme has been proposed in this paper, which requires only the instantaneous values of the three phase motor reference voltages in all of the sectors. The sector identification is achieved by comparing the components of the motor reference voltages, using simple hysteresis comparators, along the three orthogonal axes to the a,b,c phase axes. The proposed PWM strategy has been experimentally verified on a 1HP open-end winding motor and the experimental results are presented in this paper.
By N. Bianchi; S. Cervaro
In several applications where electrical motors are used, the torque ripple must be avoided, since it causes voibrations and acoustic noise. This paper deals with the analysis of the torque ripple of surface-mounted permanent magnet motors fed by squarewave currents. Differently from the previous works, the non-ideal induced back-e.m.f. waveform is considered and the current commutation is emphasised. This analysis allows some remedial strategies to be identified, in order to minimise the commutation torque ripple. Simulations and experimental results are reported, confirming the goodness of the proposed strategies.
By W. Leonhard
Electricity produced from wind or sun is not matched to consumption by electrical loads and needs to be conditioned for general use. The strategy pursued in some industrial European countries of granting priority to regenerative sources and subsidizing the infeed of raw natural energy into the electrical grid is ineffective when mainly thermal power stations are employed for grid control; the control should include regenerative sources as well. Also, part of the expected fuel saving by the use of wind or solar energy is lost through the control of the thermal stations. When further expanding the use of renewable sources it is necessary to develop large energy storage facilities for decoupling generation from consumption; chemical storage could facilitate a flexible demand-driven reconversion of electricity with stationary or mobile fuel cells. This is a wide future field for power electronics.
By M. K. Darwish; M. El-Habrouk; I. Kasikci
A novel control method for active power filters in conjunction with a cascaded passive filter circuit is presented and analysed in this paper in order to comply with EMC regulations. The principles of analysis, design, operation and control of the new circuit equipped with IGBTs are presented. This enables the compensation of rapidly changing harmonics and reactive switching power. the new configuration improves the rating of the active power filter, reducing power losses in the switches compared to existing and newly developed active filters. Furthermore, the paper also presents a mathematical modelling of the proposed system equations. the frequency response of the proposed system is also discussed. The proposed circuit has been checked using a dedicated software simulation program, which was specifically developed for this purpose. An experimental set-up has been designed and implemented in order to apply the new method using IGBTs and other passive devices.