This paper reviews the relative merits of induction, switched reluctance, and permanent-magnet (PM) brushless machines and drives for application in electric, hybrid, and fuel cell vehicles, with particular emphasis on PM brushless machines. The basic operational characteristics and design requirements, viz. a high torque/power density, high efficiency over a wide operating range, and a high maximum speed capability, as well as the latest developments, are described. Permanent-magnet brushless dc and ac machines and drives are compared in terms of their constant torque and constant power capabilities, and various PM machine topologies and their performance are reviewed. Finally, methods for enhancing the PM excitation torque and reluctance torque components and, thereby, improving the torque and power capability, are described

Electrical Machines and Drives for Electric, Hybrid, and Fuel Cell Vehicles

This paper reviews the relative merits of induction, switched reluctance, and permanent-magnet (PM) brushless machines and drives for application in electric, hybrid, and fuel cellvehicles,withparticularemphasisonPMbrushlessmachines. The basic operational characteristics and design requirements, viz. a high torque/power density, high efficiency over a wide operatingrange,andahighmaximumspeedcapability,aswell as the latest developments, are described. Permanent-magnet brushless dc and ac machines and drives are compared in terms of their constant torque and constant power capabilities, and various PM machine topologies and their performance are reviewed. Finally, methods for enhancing the PM excitation torque and reluctance torque components and, thereby, improv- ing the torque and power capability, are described.

Electrical Machines and Drives for Electric, Hybrid, and Fuel Cell Vehicles Induction and switched-reluctance machines can provide the needed characteristics, but permanent magnet brushless machines offer a higher efficiency and torque density.

Interior permanent-magnet (IPM) synchronous motors possess special features for adjustable-speed operation which distinguish them from other classes of ac machines. They are robust high powerdensity machines capable of operating at high motor and inverter efficiencies over wide speed ranges, including considerable ranges of constant-power operation. The magnet cost is minimized by the low magnet weight requirements of the IPM design. The impact of the buried-magnet configuration on the motor's electromagnetic characteristics is discussed. The rotor magnetic circuit saliency preferentially increases the quadrature-axis inductance and introduces a reluctance torque term into the IPM motor's torque equation. The electrical excitation requirements for the IPM synchronous motor are also discussed. The control of the sinusoidal phase currents in magnitude and phase angle with respect to the rotor orientation provides a means for achieving smooth responsive torque control. A basic feedforward algorithm for executing this type of current vector torque control is discussed, including the implications of current regulator saturation at high speeds. The key results are illustrated using a combination of simulation and prototype IPM drive measurements.

Interior Permanent-Magnet Synchronous Motors for Adjustable-Speed Drives

The application of vector control to the PMSM (permanent-magnet synchronous motor) is described, and complete modeling, simulation, and analysis of the drive system are presented. State-space models of the motor and speed controller and real-time models of the inverter switches and vector controller are included. Performance differences due to the use of pulsewidth-modulation (PWM) and hysteresis current controllers are also examined. Particular attention is paid to the motor torque pulsations and speed response. Some experimental verification of the drive performance is also given. >

Modeling, simulation, and analysis of permanent-magnet motor drives. I. The permanent-magnet synchronous motor drive

This brief studies dynamic characteristics of a permanent-magnet synchronous motor (PMSM). The mathematical model of the PMSM is first derived, which is fit for carrying out the bifurcation and chaos analysis. Then, the steady-state characteristics of the system, when subject to constant input voltage and constant external torque, are formulated. Three cases are discussed and, for each case, conditions are derived under which the dynamic characteristics of the system are either of steady-state type, limit cycles or chaotic, thus by properly adjusting some system parameters, the system can exhibit limit cycles (LCs) or chaotic behaviors at will. Finally, computer simulations are presented to verify the existence of strange attractors in the PMSM.

Bifurcations and chaos in a permanent-magnet synchronous motor

Two methods are presented by which the performance of ac permanent magnet machines can be predicted. The first method utilizes phasor diagrams to include core-loss. The second method uses the concept of machine admittance; this admittance is also adjusted for the effects of core-loss. The admittance also defines the shape of the current locus as a function of voltage induced by the magnets.

Performance of Polyphase Permanent Magnet Machines

The permanent magnet motor operating at subsynchronous speeds, as during run-up, is treated with particular emphasis placed on the role that magnet excitation plays. The torque, during run-up, is separated into components called the "cage torque", the "magnet torque" and pulsating components of double-slip-frequency and single-slip-frequency. Equations for calculation of these torques are derived and a comparision of the relative magnitude is given.

V. B. Honsinger

Papers

Performance of Polyphase Permanent Magnet Machines

Permanent Magnet Machines: Asychronous Operation