This paper describes the transient characteristics and control of the output DC voltage of a stand-alone switched reluctance generator (SRG). A mathematical model of switched reluctance machine (SRM) is developed and implemented in Matlab/Simulink software. The mathematical model is verified experimentally. The robust controller based on the discrete-time sliding mode control (DT-SMC) technique is proposed for the SRG voltage control. The robustness is achieved using the disturbance estimator. The proposed control technique was implemented through simulations on a three phase 12/8-pole SRG with a variable speed and load. The proposed DT-SMC based controller is compared with a standard PI controller. Obtained results show the effectiveness and quality of DT-SMC based voltage control technique for the SRG.

Phasor estimation is an essential task in power system since the voltage angle and voltage RMS determine the available active power and its flow. This paper proposes fast and simple algorithm for harmonic phasor estimation in a three-phase system. Harmonics are considered the most serious power quality (PQ) problem in the emerging scenario with a growing proportion of power electronic based devices in the power system. The algorithm is based on well-known mathematical transform and recommendations given in relevant IEC and IEEE standards. The presented algorithm can be used to generate input data for Harmonic State Estimation.

The paper describes a photovoltaic system (PVS) composed of a group of photovoltaic (PV) panels and presents the initial evaluation of power quality (PQ) in the low-power microgrid connected to these PV panels. This PVS is called solar tree and it is built as a research platform at our faculty to conduct teaching and research on renewable energy sources. The solar tree can operate in two modes: on-grid and off-grid (autonomous operation). An off-grid mode was analysed and experiments were carried out in order to determine the maximum power that can be delivered to the load connected to this autonomous photovoltaic system (APVS). Also, the various consumer's responses to a sudden load changes in this APVS were analysed. The experiments were carried out by using modern power quality monitoring devices and PQ of this single-phase APVS with energy storage is examined in terms of compatibility with the relevant international standards.

This paper describes the transient performance and voltage regulation of a stand-alone self-excited induction generator (SEIG). All characteristics are calculated with a ftux-based mathematical model of the induction machine in the stationary reference frame appropriate for the stand-alone SEIG. The generator model and the control system model are developed using Matlab/Simulink. A presented generator model takes into account significant effects of magnetic saturation on the SEIG performance. The simulation was performed by loading the SEIG with a variable resistive load. Some of the computed characteristics are compared with experimental results. Both uncontrolled and controlled response of the SEIG to load variations were analyzed. It is shown that voltage variations can be reduced by using voltage source inverter and terminal voltage controller.

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 machine's 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.

This paper describes fast analytical model for computation of the switched reluctance machine's (SRM) nonlinear magnetization characteristic and torque lookup table. The flux-tube and the gage-curve methods are used to develop this fast 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 the results of magnetostatic finite-element analysis (FEA) for a three-phase 12/8 SRM. Experimental verification of the analytical model is also presented for the same 12/8 SRM prototype.

The effects of magnetic circuit geometry on torque generation of switched reluctance motor with higher number of rotor poles are investigated in this paper. Specifically, the torque generation of novel switched reluctance machine with 8 stator and 14 rotor poles (SRM 8/14) is explored. A few suggested values of design ratios are derived for this novel SRM. The machine characteristics are computed using two-dimensional finite element method (2-D FEM).

This paper presents a novel analytical model for computation of the switched reluctance machine's (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.

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.

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.

Analysis and static characteristics optimization of the new four-phase switched reluctance machine with 8 stator and 14 rotor poles (SRM 8/14) is presented in this paper. This new configuration with higher number of rotor poles is considered to be suitable for high performance electric vehicle (EV) drives. Optimization variables were the stator and rotor poles arc angles, and the taper angle of the stator poles. The optimization objectives were to minimize torque ripple and maximize torque factor, torque quality factor, torque density and losses factor. Calculation of the static characteristics and optimization is performed by a combination of high-level technical computing language Matlab and 2D FEM software Ansoft Maxwell. The genetic algorithm (GA) is used for minimizing a weighted sum of five normalized objectives.

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.

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 machine's geometry should be optimized as well.

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.

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 motor's 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.