Senad Smaka

Switched reluctance machines for hybrid electric vehicles

This paper presents a procedure of determination of static characteristics of switched reluctance machines (SRMs). Calculations are realized for two SRM topologies including novel configuration with 8 stator and 14 rotor poles (SRM 8/14). This configuration is based on new pole design formula introduced recently. Flux linkage and static torque characteristics are calculated for different rotor positions and stator currents using two-dimensional finite element analysis (2D-FEA). Simulation results for new SRM 8/14 and conventional SRM 8/6 with the same number of phases and outer dimensions are presented and compared. This comparison shows that new configuration can have better torque density. Therefore, new design approach should be considered to make this type of machines a more attractive for high performance HEVs (Hybrid Electric Vehicles) drives.

Multi-objective design optimization of 8/14 switched reluctance motor

Two methods of the multi-objective design optimization of switched reluctance motor with 8 stator and 14 rotor poles (SRM 8/14) are compared in this paper. The first optimization method is based on using the results of Two-Dimensional Finite Element Method (2D FEM) parametric analysis of SRM 8/14. Augmented Lagrangian Genetic Algorithm (ALGA) and 2D FEM are coupled in the second optimization process. The optimization objectives are to minimize torque ripple and maximize average steady-state torque, torque factor, torque quality factor, torque density and losses factor. The optimization variables are the stator and rotor poles arc angles, the taper angles of the stator and rotor poles, stator yoke radius, rotor yoke radius, and stator coil height.

Design considerations for novel 8/14 and comparison with conventional 8/6 and 8/10 switched reluctance machines

In this paper a comparative evaluation of three, four-phase, switched reluctance machines (SRMs) is presented. Configurations 8/6 and 8/10 are conventional SRMs with standard relationship between number of stator and rotor poles. Configuration 8/14 has number of rotor poles calculated according to the new pole design formula introduced recently. Design considerations for novel SRM 8/14 are given. Static characteristics of SRM 8/6, SRM 8/10 and SRM 8/14 are investigated using finite element analysis (FEA). Comparison of these characteristics is given regarding several criterions for torque profiles evaluation and torque density assessment.

Parameter identification and digital control of speed of a permanent magnet DC motors

The digital control of speed of a permanent magnet DC motor based on a digital computer is analyzed in this paper. Datasheet information about the DC motor was initially unknown. Therefore, the parameter identification and parameter estimation of the motor was done. A type of PID controller, which parameters were optimized (PI), was used in process of controlling the speed of the motor. DAQ acquisition card was used for the purposes of motors parameter identification and realization of computer control of motor speed in closed feedback loop. Manipulations with the same DAQ card were done using Matlab/Simulink software package. Experimental results were compared with the results obtained by simulation.

Multidimensional performance optimization of switched reluctance machines

This paper presents a procedure for optimization of the switched reluctance drive, in order to achieve required torque-speed characteristics. SRM configuration and characteristics are given, and experimental verification of the modeled characteristic is presented. Genetic algorithm (GA) was used for optimization of turn-on angle, turn-off angle and voltage, which represent basic control inputs. The achieved results suggest that the machines geometry should be optimized as well.

Design of initial topology of interior permanent magnet synchronous machine for hybrid electric vehicle

The design method of initial topology of interior permanent magnet synchronous machine (IPMSM) for hybrid electric vehicle (HEV) propulsion is described in this paper. Design constraints are selected on the basis of limitations imposed by machines manufacturer and application (e.g. maximum copper slot fill factor, air gap length, permanent magnet material, limited space available in drive trains, etc.). Design variables are rotor radius, stator slot width and number of turns per phase winding. Parametric analysis is performed for various machine topologies. The cost function, which connects the distribution of operating points of HEV and the efficiency maps of various topologies of an electrical machine, is defined. Obtained parametric results are compared to find the result leading to the extreme value of the cost function. The initial design of IPMSM that corresponds to this result is considered as the best initial design.

Fast analytical model of switched reluctance machine

This paper describes a fast analytical model for computing the nonlinear magnetization and static torque characteristics of a switched reluctance machine (SRM). This model is developed using the flux-tube and gage-curve methods. The proposed model is used for computing the magnetization (flux-linkage) and torque characteristics of three and four-phase SRMs. The simulation results obtained using the proposed analytical model are compared to those obtained using magnetostatic finite-element analysis (FEA) for a three-phase 12/8 SRM and for a four-phase 8/6 SRM. Finally, experimental verification of the analytical model is presented for the 12/8 SRM and 8/6 SRM prototypes.

Excitation parameters and stability of open loop operated self-excited switched reluctance generator

This paper presents a study on output voltage of a self-excited 8/6 switched reluctance generator (SRG). A nonlinear Matlab/Simulink® model of the machine has been developed and used to determine dynamic behavior of SRG. SRG has been simulated in open loop with fixed conducting angle strategy in low speed range, with variable turn-on angle being basic excitation parameter. A relationship between output voltage and turn-on angle has been established. Load current is found to have significant influence on output voltage and stability. Boundaries of stable operation in open loop with respect to load current are determined. A proposed operation mode has been presented and tested in simulation and validated through experimental results.

A novel approach to analytically modeling switched reluctance machine

This paper presents a novel analytical model for computation of the switched reluctance machines (SRM) nonlinear magnetization characteristic and torque lookup table. The flux-tube and the gage-curve methods are used to develop the novel analytical model. Presented model is used for computation of the magnetization characteristic and torque lookup table of three and four phase SRMs. The simulation results obtained using proposed analytical model are compared to finite-element method (FEM) results. Experimental verification of the analytical model is presented for an 8/6 SRM.

Design of wound rotor low-voltage synchronous generator

Magnetic circuit design of wound rotor low-voltage three-phase synchronous generator for autonomous operation is presented in this paper. The Maxwell software based on two-dimensional finite element method (2D FEM) is used to study the performance of the synchronous generator in specified static operating regime. Two machines with different configurations are analyzed. These machines are characterized by the same stator and rotor external dimensions and used materials. Moreover, stators of all machines are exactly the same while the rotor magnetic circuit structures and excitation windings are different. Calculated characteristics and their comparisons are presented and discussed. Some characteristics of prototype, which is currently under construction, are given.