Transient analysis of a new outer-rotor permanent-magnet brushless DC drive using circuit-field-torque coupled time-stepping finite-element method

In this paper, a new outer-rotor permanent magnet (PM) brushless dc drive is designed and analyzed. To enable this drive applicable to electric vehicles, its transient performances at both normal and flux-weakening operations are particularly focused. The distinct feature in design is due to the new motor configuration including the outer-rotor topology, the multipole magnetic circuit and the full slot-pitch coil span arrangement. The distinct feature in analysis is due to the development of the circuit-field-torque coupled time-stepping finite-element method. The proposed PM brushless dc drive is prototyped. The analysis results are verified by experimental measurement.published_or_final_versio

Advanced conduction angle control of permanent magnet brushless motor drives

A novel advanced conduction angle control scheme for permanent magnet brushless motor drives is presented in this paper. The originality of this scheme is to employ the transformer EMF in stator windings to counteract the rotational EMF by controlling the advanced conduction angle when the motor drive operates above the base speed. Hence the constant-power operation region can be extended considerably, even though the current regulator is in saturation. The attractive feature of the proposed control scheme is that it has better controllability and easier to implement than conventional flux-weakening control scheme because of the absence of coordinate transformation. It can be applied to all PM brushless motors, including conventional, phase-decoupling, sinusoidal-fed and rectangular-fed types. An Intel 8098-based digital controller and a phase-decoupling rectangular-fed PM brushless motor are employed to implement the scheme. The hardware and the software are simple and flexible. Both computer simulation and experimental results of a 1-kW motor drive system verifies that the proposed control scheme works well.published_or_final_versio

A new surface-inset, permanent-magnet, brushless dc motor drive for electric vehicles

A new five-phase, surface-inset, permanent-magnet (PM), brushless dc motor drive is proposed in this paper. The motor drive has advantages of both the PM brushless dc motor drive and the dc series motor drive. The originlity is that the air-gap flux of the motor is generated by both the PM excitation and the specially controlled stator currents (two particular phases) under the same PM pole. The motor configuration and principle of operation are so unusual that the magnetic field distribution and steady-state performance are analyzed by the finite-element method (FEM). Experimental results for a prototype verify that the proposed motor drive is promising for modern electric vehicle applications.published_or_final_versio

Novel wide range speed control of permanent magnet brushless motor drives

This paper presents a novel approach for wide range speed control of permanent magnet (PM) brushless motor drive, including both sinewave and squarewave versions. As compared with conventional flux-weakening control, the approach takes definite advantages that it can be applied to the squarewave PM brushless motor drive directly, and even to the motor drive with negligible mutual inductances between phase windings. Moreover, it is easier to implement than flux-weakening control because no coordinate transformation is needed. The key of this approach is to make use of the transformer EMF in such a way that it weakens the rotational EMF when the motor operate above the base speed, leading to achieve constant-power operation. Computer simulation and experimental results show that the proposed approach works well.published_or_final_versio

Optimal efficiency control of PM hybrid motor drives for electrical vehicles

The paper deals with the control of a novel brushless PM hybrid motor to optimize its efficiency. The approach is to adaptively adjust the field current to minimize the total loss based on its potential for a high efficiency over a wide torque-speed region. The optimal controller has good performance for electrical vehicles.published_or_final_versio

Design and analysis of a new multiphase polygonal-winding permanent-magnet brushless dc machine

In this paper, a new multiphase polygonal-winding permanent-magnet brushless dc (PMBDC) machine is proposed anal analyzed. The originality of the proposed machine lies on the multiphase polygonal-winding stator anal the surface-inset permanent-magnet rotor. Because of its unique structure and operating principle, a circuit-field-torque coupled time stepping finite-element method is also employed for analysis. The designed machine is prototyped and the analysis is verified by experimentation.published_or_final_versio

Permanent magnet brushless drives

The purpose of this paper is to present an optimal efficiency control scheme for constant power operation of phase decoupling (PD) PM brushless DC motor drives. The key is to adaptively adjust the advanced conduction angle to minimize the system losses for a given operation point in the constant power region. The strategy for constant power operation of PD PM brushless DC motor drives is exemplified using a 5-phase 22-pole PD PM brushless DC motor. In the sections that follow, the newly-developed optimal efficiency control technique is then illustrated. Then, after describing the corresponding implementation, both computer simulation and experimental results are presented, and some conclusions are offered.published_or_final_versio

Optimal-efficiency control for constant-power operation of phase-decoupling permanent-magnet brushless motor drives

In this paper, a control approach to optimize the system efficiency of phase-decoupling (PD) permanent-magnet (PM) brushless motor drives during constant-power operation is presented. The approach is to adaptively adjust the advanced conduction angle to minimize the total system losses for a given operation point in the constant-power region. The corresponding minimum total losses are determined by minimizing the input current for a fixed voltage source. Both computer simulation and experimental results are given for illustration.published_or_final_versio

A novel polyphase multipole square-wave permanent magnet motor drive for electric vehicles

A novel high-power-density permanent magnet (PM) motor drive for electric vehicles (EVs) is proposed. The motor is a polyphase multipole square-wave PM motor, which can be classified as a kind of PM brushless DC motor. The distinct features of the proposed motor as compared to those of the conventional PM brushless DC motor are as follows. First, the multipole magnetic circuit arrangement enables the minimization of the magnetic yoke, resulting in the reduction of motor volume and weight. Second, the coil span is purposely designed to be equal to one slot pitch, thus saving the amount of copper used. Third, by using a fractional number of slots per pole per phase, the arrangement of the numbers of poles and slots is so unique that the magnetic force between the stator and the rotor at any rotating position is uniform, hence eliminating the cogging torque that usually occurs in PM motors. Finally, the motor can be controlled to operate at a constant torque region and a constant power region with field weakening, thus both high starting torque and high cruising speed can be achieved. Therefore, as the proposed motor drive possesses the distinct advantages of high power density, high efficiency, and superior dynamic performance, it is very suitable for EV applications. A prototype of a five-phase 22-pole 5 kW motor drive has been designed for an experimental EV.published_or_final_versio

Ciliary assessment in bronchiectasis: is there a clinico-pathological correlation?

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