Hybrid Excited Claw Pole Research Articles

Design and Optimization of Hybrid-Excited Claw-Pole Machine for Vehicle

In order to overcome the shortcomings of traditional electric excitation claw machine such as large leakage of magnetic field and easy saturation of ferromagnetic materials, a new topology structure with permanent magnet and electrical excited of shunt excitation scheme is proposed for claw-pole machine. Firstly, the output characteristics of voltage and current in power generation and electric state for claw-pole machine are analyzed by 3-D finite element method (FEM). And the influence of different excitation currents on the saturation state of magnetic circuit is calculated. On this basis, the influence of saturation of magnetic circuit is considered for electromagnetic torque and torque ripple. Therefore, under the condition of unsaturated flux density, in order to ensure the fastest and most stable start of the vehicle, it is necessary to obtain the maximum excitation current. Finally, a hybrid-excited claw-pole machine with rated power of 1.5kW is manufactured, and the on-load and no-load characteristics of prototype are tested to verify the feasibility of the hybrid-excited topology proposed.

Torque and back-emf in hybrid excited claw pole generator

PurposeThe paper aims to present the hybrid excited claw pole generator design, simulation and experimental results. The prototype has claw poles on two rotor sections, between which an excitation coil is located. The innovation of this machine is permanent magnets location on claws of one part of the rotor. The paper presents construction of the machine and analysis of the current in the excitation control coil influence on the electromagnetic torque, cogging torque and back-emf values. Presented studies enabled the determination of the torque and the back-emf for both: the strengthening and the weakening of magnetic field.Design/methodology/approachIn the study, finite element analysis was used to perform simulation research. Then, based on the simulation studies, an experimental model was built. The paper also presents selected experimental results.FindingsAchieved results show that the proposed machine topology allows to eliminate the disadvantages mentioned in paper, i.e. necessary to introduce special areas inside the machine to limit magnetic flux leakage or its complicated construction.Research limitations/implicationsThe obtained cogging torque values and back-emf pulsation are still relatively high. In the near future, some of known techniques for reducing these pulsations can be applied, including the use of magnetic wedges, changing shapes of rotor’s poles and/or skewing of permanent magnets.Practical implicationsThe proposed solution can be used in wind turbines as a generator.Originality/valueThe paper presents an original design of a new construction of a hybrid-excited claw pole machine and also an excitation current influence on cogging torque and back-emf values.

Hybrid excited claw pole generator with skewed and non-skewed permanent magnets

Abstract This article contains simulation results of the Hybrid Excited Claw Pole Generator with skewed and non-skewed permanent magnets on rotor. The experimental machine has claw poles on two rotor sections, between which an excitation control coil is located. The novelty of this machine is existence of non-skewed permanent magnets on claws of one part of the rotor and skewed permanent magnets on the second one. The paper presents the construction of the machine and analysis of the influence of the PM skewing on the cogging torque and back-emf. Simulation studies enabled the determination of the cogging torque and the back-emf rms for both: the strengthening and the weakening of magnetic field. The influence of the magnets skewing on the cogging torque and the back-emf rms have also been analyzed.

MEC-Based Sizing of a Hybrid-Excited Claw Pole Alternator

The paper is aimed at a magnetic equivalent circuit (MEC)-based sizing of a novel hybrid-excited claw pole alternator. It consists in a claw pole concept with a NdFeB permanent magnet (PM) excitation in the rotor and a dc one in the stator, with the homopolar flux eradicated owing to a magnetic barrier inserted between the stator yoke and lamination. The proposed MEC considers both linear and saturated magnetic circuit, with a focus on the modeling of the leakage fluxes. The developed model is applied for the prediction of the no-load characteristic which is validated by 3-D finite-element analysis (FEA). Then, a dual FEA-experimental validation is carried out considering the case of a dc excitation. Moreover, the proposed MEC makes the investigation of the influent sizing parameters on the machine back-electromotive force (EMF) production capability easy. This latter is enhanced owing to the integration of two ring ferrite PMs linked to the stator, along with a reduction of the volume of the NdFeB PM in the rotor. It has been found that the gained improvement is better than the benefit yielded by as many pole number ferrite PMs inserted between the claws.

FEA-based investigation of the generating capability of a novel hybrid excited claw pole alternator with improved cost-effectiveness

Purpose – The purpose of this paper is to investigate the generating capability of a novel hybrid excited brushless claw pole alternator (HEBCPA) with improved cost-effectiveness gained thanks to the substitution the rotor NdFeB-made permanent magnet (PM) with ferrite ones. Design/methodology/approach – The investigation of the magnetic features of the novel HEBCPA has been carried out using a 3D finite element analysis (FEA). Findings – It has been found that the machine generating capability is not affected by the substitution of the single rotor NdFeB-made PM by stator and rotor ferrite-made ones, which represents a crucial cost benefit. Research limitations/implications – An experimental validation of the features computed by FEA shall be considered as an outlook of the present work. Practical implications – The novel HEBCPA could be of great interest for automotive generating systems. Originality/value – The proposed HEBCPA with ferrite-made PMs is a novel concept.

An attempt to improve the sizing of a hybrid excited brushless claw pole alternator

Purpose – This paper aims at the improvement of the generating capability of a hybrid excited brushless claw pole alternator (HEBCPA).Design/methodology/approach – Following the identification of the HEBCPA influent sizing parameters, the investigation of their impact on the back‐EMF production capability is carried out considering a 3D‐finite element analysis (FEA).Findings – The HEBCPA Back‐EMF production capability is highly affected by the variation of the influent sizing parameters. A selected combination of these parameters has led to an optimized generating capability.Research limitations/implications – An experimental validation of the generating performance computed by 3D‐FEA shall be treated in the future.Practical implications – The optimized HEBCPA is of great interest for the automotive applications as well as for wind energy generating systems.Originality/value – The optimized HEBCPA is a new concept that has been proposed by the authors in a recent work.