This paper presents the evaluation of saturation and cross-magnetization effects in an interior permanent magnet synchronous motor (IPMSM) over the entire range of direct- and quadrature-axis ...excitations. The conventional two-axis machine model is modified in order to include the influence of saturation and cross-coupling effects on the variation of self- and cross-coupling inductances in the direct and the quadrature axis. The two-axis machine model parameters are evaluated by experiments performed on an IPMSM using a controlled voltage-source inverter and are compared with parameter values evaluated by the finite-element method. The evaluation of two-axis machine model parameters reveals significant saturation and cross-magnetization effects in both axes, especially in the flux-weakening regime.
The performance comparison of three- and single-phase line-start interior permanent magnet synchronous motors (LSIPMSMs) and induction motors (IMs) with equal squirrel-cage design and symmetric ...four-pole stator windings is presented. The finite element method was employed in analysis of steady-state synchronous performance of LSIPMSMs. A magnetically linear lumped parameter model was employed in analysis of line-starting performance of LSIPMSMs, where the electrical and also the mechanical subsystems were considered. The procedure which was used for the LSIPMSM design was validated by comparison of calculation and measurement results. The performance of three- and single-phase LSIPMSMs and IMs with equal squirrel-cage design was directly compared and evaluated, thus emphasizing impacts of the permanent magnet breaking torque and reluctance breaking torque on the LSIPMSM performance in the asynchronous operation region.
The properties of magnetic material are normally described by the permeability tensor, while the magnetically nonlinear properties of electromagnetic devices (EMDs) can be described by the ...current-dependent characteristics of flux linkages. This paper presents and evaluates different experimental methods appropriate for determining the magnetically nonlinear characteristics of EMDs. The tested device is supplied by a controlled voltage source. Sinusoidal voltages, sinusoidal voltages with offset, and stepwise changing voltages are applied. Current-dependent characteristics of flux linkages are determined from the measured voltages and currents, either by numerical integration or by Fourier analysis and calculation of impedances.
The line-starting performance and synchronization capability of a line-start interior permanent magnet synchronous motor (LSIPMSM) has to be evaluated by considering different loads and different ...values of supply voltages, which requires the usage of a reliable dynamic model. In this work the parameters of a magnetically linear lumped parameter LSIPMSM dynamic model were determined by the differential evolution (DE). The optimization objective was the best possible agreement between the measured and by the model calculated time-behavior of model variables. Parameters determined by the DE are used in the LSIPMSM dynamic model, improving agreement between measured and calculated responses of currents and motor speed.
This paper deals with experimental methods for the identification of linear synchronous reluctance motor (LSRM) parameters. A magnetically nonlinear two-axis dynamic LSRM model is derived. This model ...accounts for the effects of slotting, saturation, cross-saturation, and the end effects. The parameters of the obtained model are not constant. They are given by the characteristics of the flux linkages, thrust, and friction force depending on the mover position and the direct (d) and quadrature (q) axis currents. These characteristics are determined experimentally by a controlled voltage-source inverter employing closed-loop current control in the d-q reference frame. The proposed model, experimental methods, and determined characteristics are confirmed through a comparison between the measured and calculated results. Two tests are performed: a test at the locked mover, and kinematic control at low speed. The effects of cross saturation under dynamic operating conditions and the effects of slotting can be clearly seen in the measured and calculated results.
The paper presents a finite-element method-based design and analysis of interior permanent magnet synchronous motor with flux barriers (IPMSMFB). Various parameters of IPMSMFB rotor structure were ...taken into account at determination of a suitable rotor construction. On the basis of FEM analysis the rotor of IPMSMFB with three-flux barriers was built. Output torque capability and flux weakening performance of IPMSMFB were compared with performances of conventional interior permanent magnet synchronous motor (IPMSM), having the same rotor geometrical dimensions and the same stator construction. The predicted performance of conventional IPMSM and IPMSMFB was confirmed with the measurements over a wide-speed range of constant output power operation.
This paper presents a torque analysis of an axial flux permanent magnet synchronous machine (AFPMSM) based on analytical analysis of magnetic field. The proposed method for torque analysis requires ...less computational time and is more flexible than finite element method (FEM). This is important advantage, especially for the early stages of the design process. Torque measurements on prototype AFPMSM confirm the validity of the torque analysis method.
This paper deals with the differential evolution (DE)-based method for determining the magnetically nonlinear iron core characteristics of transformers and iron core inductors. The unknown iron core ...characteristic, approximated by the sum of exponential functions, is included in a dynamic model of the tested device. The approximation function parameters are determined by DE. The optimization objective is the best possible agreement between the measured and the dynamic model calculated currents in the time and frequency domains. Using the measured inrush currents and corresponding voltages, the magnetically nonlinear characteristic can be determined over a broad operational range. The inclusion of iron core characteristic, as determined by the proposed method, in the transformer dynamic model gives very good agreement between the measured and calculated currents in both transient and steady states.
This paper presents the analytical analysis of magnetic field and back electromotive force (back EMF) calculation in an axial flux permanent magnet synchronous generator (AFPMSG) without stator core. ...For the verification, the numerical analysis finite element method (FEM) of magnetic field is accomplished and comparison between analytical and numerical solution of magnetic field is presented. Both analytical and numerical solutions are obtained via magnetic vector potential, respectively. This paper also presents the comparison between analytical solution and numerical (FEM) solution of back EMF using Faraday's law. The verifications show that good agreement between analytical and numerical solution of magnetic field and back EMF is obtained. The validity of the proposed analytical method is additionally confirmed with measurements of back EMF on prototype AFPMSG with coreless stator.
This work presents an experimental method appropriate for determining magnetically nonlinear characteristics of electric machines which contain magnetically nonlinear and anisotropic iron core, ...damping windings, and permanent magnets. The method is based on the two-axis dynamic model of a three-phase machine with wye-connected three-phase stator winding. The d-axis is defined with the magnetic axis of permanent magnets (ldquoflux linkage vectorrdquo due to the permanent magnets), while the q-axis is displaced by electrical pi/2. The tested machine is supplied by a controlled voltage source inverter. Voltage in one axis is changed in the stepwise manner, while current in the orthogonal axis is closed loop controlled. The characteristic flux linkage versus current in the form of a hysteresis loop is determined numerically using the time behavior of measured applied voltage and responding current in the same axis. Unfortunately, the currents induced in the machine's damping windings or squirrel cage disturb the flux linkage characteristic determined in this way. Therefore, only the final points of each hysteresis loop, where the currents induced in the damping windings already died-out, can be used as correct points of the machine's magnetically nonlinear iron core characteristic. The proposed method is confirmed by the tests performed with a single three-phase stator and four different rotors: the reluctance rotor, the reluctance rotor with squirrel cage, the reluctance rotor with inserted permanent magnets, and the reluctance rotor with inserted permanent magnets and squirrel cage.
