Transient peak currents in permanent magnet synchronous motors for symmetrical short circuits request pdf gaston y astrid lima


This paper investigates the three-phase symmetrical short-circuit (SSC) characteristics of a permanent magnet synchronous machine (PMSM). Closed-form solutions are derived to predict both the steady-state and transient response of a PMSM to three-phase SSC hp gas online booking no faults. The developed expressions account for the impact of prefault operating conditions and include provisions for incorporating magnetic saturation effects. The influences of machine parameters and prefault operating conditions are studied to identify the key factors that have a major influence on the steady-state and peak transient values of the fault currents. It is shown that higher machine characteristic current values, reduced stator resistance, higher q-axis prefault current, and higher magnetic saturation all increase the peak transient value of the electricity billy elliot lyrics demagnetizing d-axis current. Time-stepped finite element (FE) simulation is performed to investigate the rotor demagnetization characteristics of PMSMs under SSC fault conditions. Both two-dimensional (2-D) and three-dimensional (3-D) FE simulations are used to build confidence in the fault current predictions of the developed analytical model, accompanied by experimental verification.

This paper deals with rare-earth-free permanent magnet traction machine design for C-segment electric vehicle (EV). Four different ferrite permanent magnet synchronous machine topologies having different magnets arrangement and pole-pair number, selected for their high potential, are presented and compared thanks to a computationally efficient finite-element based analysis tool that was developed purposely. It was found that flux focusing machine having 12 poles 5 gases emitted from the exhaust pipe and 72 slots outperforms in terms of torque-speed requirement fulfillment, efficiency and power to weight ratio. Influence of the magnet grade on the resilience against demagnetization under symmetrical short-circuit condition of the selected machine was then investigated. It is shown that the machine is subject to complete demagnetization if low grade hard ferrite (Ceramic 8) is adopted, thereby fostering research of new and abundantly available magnet grades is key for penetration of new and cost effective electrical machines into EV powertrain market.

Permanent-magnet generators (PMGs) have rapidly become important in renewable energy systems, portable and standby generating systems, and in many new applications in industrial, utility, aerospace, and automotive sectors. While there has been some discussion of “fault tolerance” and fault testing of an 8-MW machine has recently been reported [1], understanding the behavior of faulted PMGs remains far from complete. This paper addresses the important case of the sudden short circuit applied to large PMG machines. It explains key differences in short-circuit behavior between the PMG and wound-field generator. The subtransient reactances and time constants of the PMG are calculated by both analytical and year 6 electricity worksheets finite-element methods and applied to the classical circuit-theory simulation of the short-circuit fault. The finite-element method is also used to assess in detail the risk of loss of magnetization in the magnets. The complexity of the transient magnetic field requires transient nonlinear circuit-coupled finite-element analysis in three dimensions with voltage-source excitation. This paper concludes with a review of the methods of calculation and a discussion of implications for future design and application of the PMG, including factors relevant to the application of standard tests and specifications.

This paper presents a technique to measure the velocity of permanent magnet synchronous motors (PMSMs) by sensing the external stray magnetic field outside the stator yoke. A magnetic equivalent circuit model for the surface-mounted PMSM was developed to analyze the behaviour of the stray magnetic field. The external stray magnetic field can provide gas efficient cars under 10000 the position and speed information of motor … [Show full abstract] rotor. Simulation by means of a three-dimensional (3D) finite-element-method (FEM) modeling and experimental results over a wide speed range are presented to substantiate the successful application of the proposed technique. A sensitive triaxial tunneling magnetoresistive (TMR) sensor was employed to measure the stray magnetic field outside the motor 3 gases in the atmosphere stator yoke. The proposed method was validated in both steady and transient operating conditions, and it demonstrated small measurement errors in the range between -0.17% and 0.55% over the speed range from 50 to 1000 rpm. Therefore, it verifies that the proposed technique can provide an easy-to-operate, low-cost and high-accuracy alternative to the velocity measurement for PMSMs. View full-text