Lucian Tutelea

Automotive Electric Propulsion Systems With Reduced or No Permanent Magnets: An Overview

Hybrid and electric vehicle technology has seen rapid development in recent years. The motor and the generator are at the heart of the vehicle drive and energy system and often utilize expensive rare-earth permanent magnet (PM) material. This paper reviews and addresses the research work that has been carried out to reduce the amount of rare-earth material that is used while maintaining the high efficiency and performance that rare-earth PM machines offer. These new machines can use either less rare-earth PM material, weaker ferrite magnets, or no magnets; and they need to meet the high performance that the more usual interior PM synchronous motor with sintered neodymium-iron-boron magnets provides. These machines can take the form of PM-assisted synchronous reluctance machines, induction machines, switched reluctance machines, wound rotor synchronous machines (claw pole or biaxially excited), double-saliency machines with ac or dc stator current control, or brushless dc multiple-phase reluctance machines.

PM-assisted reluctance synchronous motor/generator (PM-RSM) for mild hybrid vehicles: electromagnetic design

This paper introduces the conceptual design and finite-element method analysis of a permanent-magnet-assisted reluctance synchronous motor/generator for mild hybrid vehicles where a large constant power speed range (6:1) is required and machine volume, converter peak kVA, and battery size are the main constraints. Careful flux-barrier and permanent-magnet sizing, high magnetic saturation, and current density are the main requirements for maximum torque production with constraint volume. A specific tangential force density of 4.33 N/cm/sup 2/ is obtained. Rated (continuous) power-battery limited is 2.5 kW at 42 V dc, from 1000 to 6000 r/min. The peak torque of 140 N/spl middot/m is obtained at 202 A (rms/phase) and can be secured up to 500 r/min. Peak power is still 7.85 kW at 6000 r/min at 42 V dc with an efficiency of 90%. Preliminary results on a prototype are also available.

DTFC-SVM motion-sensorless control of a PM-assisted reluctance synchronous machine as starter-alternator for hybrid electric vehicles

Permanent magnet-assisted reluctance synchronous machine (PM-RSM) starter alternator systems are credited with good performance for wide speed range in hybrid electric vehicles. This paper proposes a motion-sensorless motor/generator control of PM-RSM from zero speed up to maximum speed, using direct torque and flux control with space vector modulation. A quasioptimal stator flux reference with a flux versus torque functional is proposed. A stator flux observer in wide speed range uses combined voltage-current models for low speeds, and only the voltage model for medium to high speeds, both in proportional-integral closed loop. A novel rotor speed and position observer with a fusion strategy employs signal injection and only one D-module vector filter in stator reference for low speed, combined with a speed observer from the stator flux vector estimation-for medium-high speed. The proposed system is introduced piece by piece and then implemented on a dSpace 1103 control board with a 350-A metal-oxide-semiconductor field-effect transistor-pulse-width modulation converter connected to a 42-Vdc, 55-Ah battery, and a 140-Nm peak torque PM-RSM. Extensive experimental results from very low speed to high speed, regarding observers and drive responses, including artificial loading (motoring and generating), seem very encouraging for future starter-alternator systems

Linear Permanent Magnet Oscillatory Machine: Comprehensive Modeling for Transients With Validation by Experiments

A linear and respective nonlinear state space model of a linear permanent magnet oscillatory machine is defined and then its parameters are computed from tests. The experiments were performed on two linear machine prototypes, one with interior permanent magnets and flux concentration and the other with surface permanent magnets. The finite element method model, validated on the existing prototype, shows further improvement possibilities of the interior permanent magnet machine. Dynamic tests and simulations with mechanical coupling of the two machines are used to validate the model in motion and on load. Good agreement between theory and tests in terms of various variables, including the linear position measured with a Laser-based transducer, has been observed.

BEGA - a biaxial excitation generator for automobiles: comprehensive characterization and test results

This paper presents the design and test results for a biaxial excitation generator/motor for automobiles (BEGA), which has a three-phase stator and a salient-pole excited heteropolar rotor with multiple flux barriers filled with low-cost permanent magnets (PMs). For this new generator, the low-voltage regulation is obtained by the flux-barrier PM combination with field (excitation) low-power control and a full-power diode rectifier in the stator. Good power/volume and superior efficiency (up to 80%) are obtained at costs comparable to those of an existing Lundell generator. The generator configuration, principle, equations, finite-element field analysis, design optimization, performance characteristics, and test results, together with the generating system simulations, constitute the core of the paper.

FEM analysis and control of a tapered airgap single phase PMSM

The present paper investigates by FEM, on a case study, the gradual airgap surface PM single phase synchronous motor to obtain a good compromise between starting torque, average torque and torque ripple. Then, based on a dynamic circuit model, the torque pulsations with trapezoidal current control is explored through digital simulations with about 80%( from average rated torque) initial self-starting torque.

Novel motion sensorless control of stand alone Permanent Magnet Synchronous Generator (PMSG): harmonics and negative sequence voltage compensation under nonlinear load

The present paper introduces a novel harmonics voltage compensation solution for nonlinear (diode rectifier) load operation in stand alone PMSG with bidirectional converter motion sensorless vector control. Both the case of three phases and two phase output of the load side converter, with voltage symmetrisation by negative component active cancellation, are treated. The latter is called unbalanced load handling. The main solutions for motion sensorless vector control of the two back-to-back PWM converters with loops to compensate output voltage harmonics and its negative sequence for diode rectifier load are introduced, implemented and validated through experimental results on 2.2 Kw PMSG systems.

Motion Sensorless Bidirectional PWM Converter Control with Seamless Switching from Power Grid to Stand Alone and Back

This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase-locked-loop technique, from grid connected to stand alone and vice versa in the event of a fault on grid is proposed. Tests results show the proposed method works properly

Power Electronic Drives, Controls, and Electric Generators for Large Wind Turbines - An Overview

Abstract—Wind represents a major and growing source of renewable energy for the electric power systems. This article provides an overview of state-of-the-art technologies and anticipated developments in the area of power electronic drives, controls, and electric generators for large multi-megawatt wind turbine systems. The principal components employed in a turbine for energy conversion from wind to electricity are described, and the main solutions that are commercially available are briefly reviewed. The specific issues of complex mission profiles, power codes, and reliability are discussed. Topics of power electronics, ranging from devices to circuit topologies, and similar matters for electric generators, together with results of optimal design studies are included. It is shown that the individual power rating of wind turbines has increased over the years, and technologies required to reach and exceed a power rating of 10 MW are discussed. The role of power electronics for improving the operation of wind turbines and ensuring compliance with power grid codes is analyzed with a view at producing fully controllable generation units suitable for tight integration into the power grid and large-scale deployment in future smart power systems.

25 kW, 15 krpm, 6/4 PMSM: Optimal design and torque pulsation reduction via FEM

In these days, the choice of the right motor topology for industrial applications and household electrical appliances is a challenging quest. Since universal motors can not meet the ever-growing standards of electrical equipment design, new generations of electric machines compete to conquer this market. For industrial applications and home appliances, PMSMs seem to be the most fitted solution, especially at high speed operation. In this paper, a 25 kW, 15 krpm, 6/4 PMSM is presented and analyzed via FEM, as a cost effective solution. Optimal design through Hooke-Jeeves method is; presented. The problem of cogging torque reduction is discussed and several techniques are used to reduce total torque pulsations. Results obtained via FEM are analyzed, in order to apply the best technique for our case, without compromising design requirements, low manufacturing costs and high efficiency.