Omer Cihan Kivanc

Development of high efficiency multi-output flyback converter for industrial applications

This study presents the development processes of a high-efficiency two-output flyback-converter. The detailed design phases are presented together with encountered design obstacles, limitations and the methods to overcome them. Despite their widely use in industry, studies on high-efficient flyback converter design still remains a need. Most of the flyback converters are designed with multi outputs for their various input voltages. This study firstly describes the preliminary design stages, modeling studies and definition of magnetic and electronic components and PCB design processes followed by a prototype manufacturing. Modelling study is conducted in MATLAB/Simulink environment, and PCB design is realized in Altium Designer Software. Prototype is tested and its performance parameters are recorded. It is seen that the performance values are good agreement with those of design objectives.

A simple least squares approach for low speed performance analysis of indirect FOC induction motor drive using low-resolution position sensor

This paper investigates an ordinary least squares based indirect field oriented control (IFOC) of induction motor at very low speed range (1–5 rpm) using a low-count encoder. At very low speeds the speed estimation provided by common techniques for low-count encoder applications such as averaging the last two speed samples and/or considering the previous speed value until the next position update can generate erroneous speed results which can cause instability in the overall control system. By proposing ordinary least squares (OLS) method with low-resolution position sensor based speed estimation for IFOC of IM drives more realistic speed can be obtained by fitting the predefined sets of speed data in a linear or quadratic manner. Experimental tests prove that the proposed scheme which is constituted of OLS (linear) speed estimation algorithm increases stability and improves low and oscillating speed performance of IFOC of IM drive with low-count encoders down to four pulses per revolution.

Comparison of different line start interior permanent magnet synchronous motor types with respect to IE4 efficiency class

Recently, the increasing requirements and tendencies of higher efficiency systems have caused a substantial impact on electric motor design. Designers tend to change their views on motor topologies to provide the predetermined values of higher efficiency classes (such as IE3, IE4, IE5). Line-start interior permanent magnet synchronous motors (LSIPMSM) are strong candidates for higher efficiency class general purpose motors due to their higher MTPA (maximum torque per ampere) values. In this study, three different rotor types of LSIPMSM, i.e. V-magnet type, spoke-magnet type and rectangular-magnet type, are investigated with regard to efficiency requirements of super premium efficiency class (IE4). The impact of designs on rotor cage which is essential for starting and synchronization is also studied. The electromagnetic design study is conducted and then the optimized designs are manufactured and tested. The most applicable motor type is determined by means of its ease-of-manufacture and low cost features.

Different filter approaches and performance analysis of fundamental sensors in autonomous ground vehicles

Autonomous ground vehicles are being designed and produced for industrial or military purposes. Since most of these vehicles are high cost the sensors used are high sensitive. However, sensors used in low cost robotic applications have low resolution. When non-precision sensor data added to measurement errors caused by different typical of geometry and drive methods, process functions of robots are hitching. To prevent this, five simple-structured filters are designed and compared in this study for low cost distance sensors and GPS sensors data. It has been observed that accuracy of hybrid-structured filters are more suitable than mono-structured filters in the results obtained.

In pursuit of proper BLDC motor design for electric bicycles

In this paper, an electric bicycle motor design study is presented according to the related standard. Fundamental dimensions and characteristics are kept within some certain boundaries by means of motor rated power and physical constraints arising from standard bicycle sizes available on the market. Slot/pole ratios and winding configurations are investigated comprehensively in order to obtain a proper design of electric motor due to the facts of pedal assisted electric bicycle application. After defining the motor parameters and the materials that are used the motor design an optimisation attempts are undertaken by using an analytical solver which is employing both numerical calculations and finite element method (FEM) analyses. Motor designs are assessed based on torque production, weigh, efficiency and ease-of-manufacture. A concise experimental study is conducted for prototype motor in order to evaluate validity of design study.

On regenerative braking capability of BLDC motor

The solution for range problems in electric vehicles is implying two essential approaches: consuming electrical energy with maximised efficiency and regenerative braking. Regenerative braking can be implemented by using the any converter used for electric motor control without needing an extra power circuit. To accomplish recovering electrical energy from mechanical energy a voltage boosting operation is necessary which is causing the current flow from induced voltage due to the mechanical motion to battery. In this study, a brushless DC (BLDC) motor drive system used for light electric vehicle propulsion is modeled by considering non-linear effects. The developed model of the motor drive system is used for defining the upper limits and constraints of operation. Analytic calculations and simulation results represent the operation modes of the system when regenerative braking is applied.

Electro-hydraulic power steering system modelling for parameter fault detection based on model reference adaptive frame

A simple and efficient fault detection and parameter monitoring algorithm for electro-hydraulic power steering (EHPS) system is proposed using model reference adaptive system (MRAS) without any additional sensor. In a faulty situation where the hydraulic system is disabled, assisted power is provided by an electric motor. Therefore, in low speed maneuvers, during sudden direction changes and parking, some parameters of an electric motor in EHPS are affected. These changes threaten the vehicles driving reliability and performance of EHPS. In this study, an EHPS system with rotor flux estimation based adaptive driver torque control principle has been presented. The motor winding temperature is obtained for monitoring purpose with the help of MRAS stator resistance estimation. The proposed parameter estimation method for EHPS has been simulated by using AMESim and MATLAB/Simulink cosimulation model. Simulation results demonstrate the feasibility and effectiveness of the proposed method.

Design and manufacture of electric powertrain and its cooling system for ITU EV project

In recent years all expositions of cars show that every car manufacturing company is developing at least one electric vehicle. Recently, ITU ALEK (Istanbul Technical University Alternative Energy Club) members and its supervisor created an electric vehicle project called ITU EV (electric vehicle). This project is about developing a drive system for a conventional internal combustion engine (ICE) vehicle. The project which started in 2011, has four different main research areas. These are electric powertrain which includes water cooling design, battery part, controlling part, mechanical construction and outer design part. In this study, electric powertrain design, cooling calculations and design, and production parts of the project will be investigated. For electric drivetrain a special design of 70 kW BLDC (brushless dc) motor is produced and laboratory tests are made. The rated voltage is chosen as 355 V.