Mohamed K. El-Nemr

A less sensor control method for standalone small wind energy using Permanent Magnet Synchronous Generator

This paper proposes a new control strategy using less number of sensors for variable speed wind energy conversion system (WECS). Maximum Power Point Tracking (MPPT) algorithm, and near unity power factor correction control (UPF) are achieved at the generator side using direct driven Permanent Magnet Synchronous Generator (PMSG). The PMSG operates at variable wind speed connected to a full controlled active rectifier employing both unity power factor and MPPT control. The dc-link voltage is controlled to be fixed using a storage system through bi-directional power flow link to achieve power flow control with MPPT. Simple Hysteresis control is applied for the fully controlled active rectifier. The full system has been analyzed and simulated using PSIM to examine its performance. Then, a prototype has been built and tested in the laboratory. Some selected experimental results are provided for the validation of the system.

Optimum design of high efficiency power conditioning wind energy system

This paper introduces a study for the small wind energy conversion system (WECS), which aims to select the optimum design parameters to achieve high performance system. The main features of the studied system are high efficiency, operation at maximum power point tracking (MPPT) and long battery lifetime. The Permanent Magnet Synchronous Generator (PMSG) operates at variable wind speed and it is connected to a full controlled active rectifier. The dc-link voltage is controlled to be fixed by using a storage system through Bi-directional power flow link. As the battery is the most costly part in the small WECS, the controller should have the ability to reduce the battery current ripple, which results in longer life for the battery. It is found here that the designed dc voltage level is the main factor that affects the battery current ripple. Therefore, a full study for choosing the optimum dc voltage level that results in better system performance is provided. A maximum power point tracking control is employed using hysteresis control for the fully controlled active rectifier. The complete system is studied, analyzed and simulated using PSIM to validate the system performance.

Design and simulation of a battery powered electric vehicle implementing two different propulsion system configurations

This paper presents a design and simulation of a powertrain system for battery powered electric vehicle (EV). Two different configurations are used for the EV propulsion system. The rear wheels of EV are driven by one traction motor through a differential system, and the front wheels are driven by two other traction motors coupled directly in-wheels. Permanent magnet synchronous motors (PMSM) are adopted as the traction motors. Rule-based power management and control (PMC) strategy is presented to manage and control the power flow between rear and front drive systems. Simulation of the whole EV model is established using AVL CRUISE. Vehicle performance under the new European driving cycle (NEDC) is calculated and presented in the simulation results to specify the potential of the proposed system.

Real time implementation of high performance closed loop embedded control system for interior permanent magnet motors

Aiming at achieving a low cost and precise closed loop speed control of interior permanent magnet synchronous motor (IPMSM), this paper introduces an implementation of cost effective real time embedded control system. Scalar (constant V/f) closed loop speed control strategy was implemented using a conventional PI regulator in conjunction with space vector pulse width modulation (SVPWM) technique. The motor speed has been obtained using incremental shaft encoder with reasonable resolution and price. Due to the necessity of accurate position and current measurements, fast PI controller actions, and digital implementation of SVPWM technique, a suitable digital signal controller (DSC) has been used as the computing and control center. Optimized embedded software was developed using C programming language combined with assembly instructions. Several experimental results show that the proposed drive system has a worthy dynamic response and precise tracking of the speed trajectory in a wide speed range, including zero speed without losing synchronization.

Variable speed drive system of a line-start interior permanent magnet synchronous motor for industrial applications

This paper presents a cost-effective adjustable speed drive (ASD) system of a line-start interior permanent magnet synchronous motor (LSIPMSM). The proposed drive system based on the digital implementation of space-vector pulse width modulation (SVPWM) using a low-cost digital signal controller (DSC). Finite element analysis (FEA) is used to determine stator self-inductances. While, other motor parameters are determined experimentally. Both simulation and experimental results are presented and discussed.

Finite-element-based design of axial field PMSG for wind energy conversion with MPPT control

Day after day, wind energy is cutting wider segment of energy market. Its clean nature and low running cost make it a good competitor for the traditional and the other renewable energy sources. The electrical generator is the key component of the wind energy generating system. Properly designed generator can maximize the energy gain. Axial field permanent magnet synchronous generator is the choice whenever the axial compactness and the simple manufacturing are the main concerns. This paper presents a three-dimensional finite element based design for a double-rotor single-ironless-stator permanent magnet axial field synchronous generator suitable for simple manufacturing and high efficiency wind generating systems. The dynamic performance of the designed generator is tested when coupled to a wind turbine to clarify its advantages when used for this type of applications. A MPPT control system is adopted to extract the maximum available power from the wind. The simulation results clearly show the effectiveness of the proposed generating system.

Correlative angles switching technique for switched reluctance motor drive systems

Switched reluctance machines with its uncomplicated structure, low cost, high reliability and fault tolerance, is struggling to gain higher market share almost in all electric machinery utilities. Its simplicity encouraged researchers to apply a wide variety of classic and intelligent control techniques. These techniques are used to control the speed and torque via appropriate determination of switching-on and switching-off angles, usually associated with applying chopping in between. However, the nonlinear nature of the machine forced the utilization of sophisticated models to assist speed and torque controllers to select proper switching angles. Especially at high speeds, the uncontrolled current during freewheeling may produce negative torque and consequently torque ripples. Considerable research efforts have been performed to reduce such ripples. In this paper, a new switching technique is proposed. The technique aims to deal with the current waveform during excitation and freewheeling as a whole via correlating the switching-on, switching-off and current-end angles using simple calculations. The restrictions and limitations imposed on each switching angle to mollify operation conditions are investigated. An extensive simulated study is carried out to validate the reliability of the proposed technique. The results show the effectiveness of the proposed control method for practical high-speed applications.

Design and performance evaluation of halbach array linear generator for wave energy converters

Linear generators have been proposed as a proper power take-off system for direct-drive wave energy conversion. Coupled directly to a reciprocating wave energy device, it was proposed that linear generators could replace hydraulic and pneumatic systems. Here we established the design and performance evaluation of a permanent magnet linear generator that implements Halbach array arrangement. The designed generator is suitable for direct energy extraction from sea waves at small wave amplitude. The electromagnetic design is performed using a finite element method and space harmonic analysis. A comparative study is performed between Halbach array and conventional air-cored linear generators to demonstrate the effectiveness of the proposed design. The equivalent circuit based model is utilized to investigate the dynamic performance of the Halbach array generator. The simulated dynamic performance of the designed generator clarifies that the implementation of Halbach array arrangement would improve energy extraction and voltage waveform.

Prediction of inductor AC power loss in PSiP buck converter based on Steinmetz parameters

Miniaturization of magnetic components employed in power electronic devices is interrelated to increasing switching frequency. That increases the need of studies on magnetic components at high frequency, above 1MHz. Some models have been developed for core loss calculations. Models based on Steinmetzs parameters are the most convenient ways. However, these models are still in need for more validation for small size components, especially at high switching frequencies. This study aims to validate recent models of AC power loss for inductor integrated in buck converter switching at frequencies higher than 1MHz showing their limitations. Then, a systematic way to correct inductor Steinmetzs parameters based on device level measurements is developed to improve correlation of predicted results.

Distributed interactive power system simulator using Web technology

Power-system simulator is considered an essential tool for design, operation, and control of electrical power systems. The nature of power-system enforces its simulation into sophisticated mathematical models and matrix calculations. Consequently, several research efforts were directed to develop numerical techniques that include efficient mathematical methods for various power system problems. Along with these developments, valuable research efforts are directed to developed efficient single-line diagram visualization, these efforts emphasize many beneficial software aspects such as reusability and extendibility of the developed applications. On this context, several endeavors are oriented for Web-based powersystem simulation. This paper introduces a Web-based application designed to provide flexible, reliable and extendable power system simulator topology. The developed application brings together the features of Web and desktop applications together. The proposed application deploys Microsofts ActiveX technology using Microsoft foundation classes (MFC). The graphical user interface is implemented using HTML and Java Script which has been linked to the developed ActiveX control. The developed application presents a valuable tool for power system simulation through the WEB keeping into consideration features of the desktop applications.