Search

Recently, permanent magnet type linear synchronous motors have been used as a driving source of transportation systems, to satisfy requirements such as speeding up of transportation systems and also to simplify maintenance. The authors' laboratory has proposed a stationary discontinuous armature PM-LSM in which the armature is engaged only when accelerated and decelerated operation is necessary, in order to resolve the problem of higher costs, when PM-LSM is used with long-distance transportation systems in factories. However, the stationary discontinuous armature PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem, because the cogging force that they exert influences the controllability of the motor. This paper presents the results of an experimental examination and three-dimensional numerical analysis by the finite element method of the cogging force exerted by the outlet edge. Moreover, we modified the permanent magnet on the mover to decrease the cogging force at the outlet edge, and the results are examined using three-dimensional numerical analysis by the finite element method. Index Terms--Cogging force, discontinuous arrangement, energy conversion, linear synchronous motor, outlet edge, skew, three-dimensional numerical analysis.

This paper presents a control strategy that provides fault tolerance to the major sensor faults which may occur in an interior-permanent-magnet-motor (IPMM)-based electric vehicle propulsion drive system. Failures of a position sensor, a dc-link voltage sensor, and current sensors are all included in the study assuming no multiple faults. For each possible sensor fault, a corresponding method of detection or diagnosis is provided. Additionally, once the fault is detected, the control scheme is automatically reconfigured to provide post-fault operational capability. A state observer is used to provide missing current information in the case of current sensor faults. Experimental results demonstrate the effectiveness of both the fault detection algorithm and the reconfigurable control scheme. The resulting IPMM drive system proves to be resilient to sensor failures while providing smooth transition to the post-fault operational mode. Index Terms--Fault tolerance, reconfigurable control, sensor fault, state observer.

This paper presents a method using carrier-frequency injection to estimate the initial rotor position and magnetic polarity for an interior permanent-magnet synchronous machine. A nonsaturating inductance model of the machine provides no information about the polarity of the rotor magnet because the position observer based on this model is locally stable at both poles. To distinguish the polarity of the rotor magnet, the magnetic saturation effect can be used. The Taylor series can be used to describe the nonlinear magnetic saturation relationship between the current and the flux linkage in the d-axis rotor reference frame. The second-order term produces the second harmonic component of the carrier frequency, and the sign of its coefficient identifies the polarity of the rotor magnet being tracked. Both simulation and experimental results show good response of the position observer at several rotor electrical positions using either a rotating vector in the stationary reference frame or a oscillating vector in the estimated rotor reference frame. Index Terms--Carrier-frequency injection, initial rotor position, magnetic polarity, second harmonic component.

This paper presents the design and implementation procedures of a control scheme for a high-performance induction motor drive for the traction purpose of full-scale electric vehicles to be series produced. For automotive use, the control scheme is designed with the expectation of possible advances in energy efficiency by adopting maximum-torque-per-ampere control and in robustness by employing extensive compensations for variations in magnetic flux, temperature, and voltage. The control scheme is then validated in the course of the bench test, followed by the in-vehicle test. [ABSTRACT FROM PUBLISHER]

Novel analysis and design methodology using the newly adopted synthetic flux linkage for interior permanent-magnet (PM) synchronous motors (IPMSMs) with a multilayered PM have been proposed. In addition, cross magnetization between the d and q axes in the IPMSM is taken into account via the proposed synthetic flux linkage, which can be identified numerically and experimentally. It is validated with the experimental ones for the purposely built prototype, and its further effectiveness on control application is introduced. [ABSTRACT FROM AUTHOR]

This paper suggests an isolated dc/dc converter using an unregulated LLC converter for fuel cell applications. The LLC converter operates as an isolated voltage amplifier with a constant voltage gain, and a nonisolated converter installed in the input stage regulates the output voltage under a wide variation of fuel cell stack voltage. By separating the functions, the unregulated LLC converter can be operated at an optimal switching condition, and the high-frequency operation of 300 kHz can be accomplished without introducing an excessive switching loss. The prototype converter with a 1-kW design (Vin = 24 \sim 48\ \V/Vo = 400\ \V) shows an efficiency of above 90.2% under a 24-V input and full load conditions. [ABSTRACT FROM AUTHOR]

This letter suggests a two-stage isolated/bidirectional dc/dc converter with three bridges. Two bridges are used for electrical isolation and constant gain, and the bidirectional control is accomplished through only a single bridge. RMS currents in the high-voltage source and link capacitor can be alleviated by capacitor division and synchronizing operation of both stages. This structure provides a simple control scheme and removes snubber circuitry, so a high efficiency can be obtained under a high switching frequency regardless of operational modes. [ABSTRACT FROM AUTHOR]