Selin Ozcira

Speed control of permanent magnet synchronous motor based on direct torque control method

As technology improves, studies on permanent magnet synchronous motors have increased and became to major on field oriented control and direct torque control methods. The main topics of permanent magnet motor control are mathematical modelling, voltage feed inverter model, space vector modulation and determination of voltage vectors. In this study, the structure and direct torque process of the PMSM (permanent magnet synchronous motor) is explained and speed control system simulation is realized for low voltage-high power PMSM.

Direct Torque Control of permanent magnet synchronous motor using LP filter

In this study, direct torque control (DTC) of the permanent magnet synchronous motor has been analyzed, the stator flux and voltage space vectors are studied and a simulation of the direct torque control of a permanent magnet synchronous motor is realized. Afterwards, an additional LP filter is attached to the simulation setup in order to suppress harmonics on the current and voltage. Torque and flux, the main variables of the DTC, are estimated using the mathematical model of the motor. Estimated torque and flux values are compared to the reference values on every control cycle and according to the torque and flux demand, voltage vector is determined. The basic approach on voltage vector determination is the table method. In this study, an inverter switching table is built for the permanent magnet synchronous motor control and direct torque control is performed by selecting the appropriate stator space vectors from the table. LP filter - which utilizes voltage model is presented and simulation aspects are analyzed.

An economical aspect for energy focused SWOT analysis of Ukraine

In this study, the general position of Ukraine in world energy arena is analyzed based on the energy policies, and also the effective parts of energy production are analyzed. Ukraine has applied for negotiations to become an EU member. In this process, the issues of energy effectiveness, their contribution to the environmental factors, proprietorship issues of the energy producers, and privatization steps are being discussed. Based on these instructions, a cross-cutting construction is performed and the energy focused SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis is conducted.

Prediction wind energy potential using by wind data analysis in Bababurnu-Turkey

In Turkey, the importance of the renewable energy resources, and the number of the renewable energy power generation plants are increasing. Wind power has a considerable share, and the investments on this sector are growing. The first step of the electricity generation from wind power process consists of feasibility and wind potential studies. In this study, the wind power map and wind potential analysis are conducted for Canakkale & Aegean Region of Turkey using WAsP software. Also the distribution of the ideal wind power over the topography of the area is analyzed.

Dynamic performance and analysis of direct torque control method based on DSP for PMSM drives

This paper presents theoretical analysis and experimental verification of the direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drive. PMSM drive is characterized by the direct torque control based on space vector pulse-width modulation (SVPWM) method which is controlled by digital signal processor (DSP). Since the constant switching frequency is produced by SVM technique, the space vector PWM control method enables the drive to produce voltage vector of any direction and magnitude thus, torque ripple is eliminated compared with classical hysteresis DTC. The proposed DTC method includes simplified reference flux vector calculator and torque estimator introducing space vector pulse-width modulation (SVPWM) method. Experimental results obtained by a motor & generator setup are shown to verify the operating principle and performance. As a result, the experimental setup exhibits validity of the analysis and to demonstrates good dynamic response.

Direct Torque Control of Permanent Magnet Synchronous Motors

Modern electrical drive systems consist of; power electronics components, transformers, analog/digital controllers and sensors or observers. The improvements in the semiconductor power electronic components have enabled advanced control techniques with high switching frequency and the high efficiency. Complex control algorithms have been widely used and got simplified in drivers due to the developments in software technology. DC, asynchronous and synchronous motors are frequently used motor types with these driver systems. New kinds of motors are developed like linear motors, step motors, switching reluctance motors, and permanent magnet synchronous motors. Permanent magnet synchronous motors are used where in general high demands are made with regard to speed stability and the synchronous operation of several interconnected motors. They are suitable for applications where load-independent speeds or synchronous operation are required under strict observance of defined speed relations within a large frequency range. As the technology gets improved, studies on PMSM such as direct torque control method have been improved as well. DTC has many advantages such as faster torque control, high torque at low speeds, and high speed sensitivity. The main idea in DTC is to use the motor flux and torque as basic control variables, identical to the DC drives. In order to emulate the magnetic operating conditions of a DC motor, the information regarding the rotor status is required to perform the field orientation process of the flux-vector drive. This information should be obtained by feeding the rotor speed and angular position back by using a pulse encoder. Encoders are costly and they add more complexity to the overall system. Several methods have been developed to obtain the rotor position and angular speed from the electrical measurements and computations in order to eliminate the need for sensors. The idea behind such methods is to manipulate the motor equations in order to express motor position and speed as functions of the terminal quantities. In (Adreescu & Rabinovici, 2004) self tuning speed controller and Luenberger observer was proposed, however it is still necessary to use an encoder for rotor position detection. Most of the methods; however, work only when the rotor is anisotropic and if the dependence of the inductance on the rotor position is accurately known; moreover, the speed is not estimated, thus the drive is not completely without mechanical sensors (Yan et al, 2005). On the other hand, it can be reported that the method in (Bolognani et al, 1999) can a viable solution for the online determination of the rotor position and speed of a PMSM. In (Ichikawa et al, 2003) extended

Wireless Power Transfer by Using Magnetically Coupled Resonators

In this chapter, a wireless power transmission system based on magnetic resonance coupling circuit was carried out. Mathematical expressions of optimal coupling coefficients were examined with the coupling model. Equivalent circuit parameters were calculated with Maxwell 3D software, and then, the equivalent circuit was solved using MATLAB technical computing software. The transfer efficiency of the system was derived using the electrical parameters of the equivalent circuit. System efficiency was analyzed depending on the different air gap values for various characteristic impedan‐ ces using PSIM circuit simulation software. Since magnetic resonance coupling involves creating a resonance and transferring the power without the radiation of electromag‐ netic waves, resonance frequency is a key parameter in system design. The aim of this research was to define the efficiency according to variations of coefficients in wireless power transfer (WPT) system. In order to do that, the calculation procedure of mutual inductance between two self-resonators is performed by Maxwell software. Equiva‐ lent circuit is solved in circuit simulator PSIM platform. The calculations show that using the parameters that are obtained by magnetic analysis can be used for the equivalent circuit which has the capability to provide the efficiency using electrical quantities. The chapter discusses the application of this approach to a coil excited by a sinusoidal voltage source and a receiver coil, which receives energy voltage and current. Both could be obtained to calculate the instantaneous power and efficiency. To do so, the waveforms for voltage and current were obtained and computed with the PSIM circuit simulator. As the air gap between the coils increased, the coupling between the coils was weakened. The impedance of the circuit varied as the air gap changed, affecting the power transfer efficiency. In order to determine the differences between the software programs, efficiency values were calculated using three kinds of software. And it is concluded that equivalent circuit analysis by means of numerical computing is proper to obtain the voltage and current waveforms. Correspondingly, transmission efficien‐ cy can be calculated using the electrical relations.

Examination of Efficiency Based on Air Gap and Characteristic Impedance Variations for Magnetic Resonance Coupling Wireless Energy Transfer

In this paper wireless power transmission system based on magnetic resonance coupling circuit was carried out. With the research objectives based on the mutual coupling model, mathematical expressions of optimal coupling coefficients are examined. Equivalent circuit parameters are calculated by Maxwell software, and the equivalent circuit was solved by Matlab software. The power transfer efficiency of the system was derived by using the electrical parameters of the equivalent circuit. System efficiency was analyzed depending on the different air gap values for various characteristic impedances. Hence, magnetic resonance coupling involves creating a resonance and transferring the power without radiating electromagnetic waves. As the air gap between the coils increased the coupling between the coils were weakened. The impedance of circuit varied as the air gap changed, affecting the power transfer efficiency.

Hybrid energy storage power allocation and motor control for electric forklifts

Enhancing transportation efficiency is the preeminent place to start efforts to minimize emissions of carbon dioxide which is a crucial malefactor in global warming. Due to awe-inspiring advantages over vehicles with internal combustion engines, use of electric vehicles (EVs) finds application in a variety of areas. However, energy storage system (ESS) of the EV plays an important role in EVs performance and can be a limiting factor in its utilization. To mitigate problems arise from ESSs, different storage equipment can be combined into an integrated hybrid energy storage system (HESS). In this paper, the effectiveness of a HESS comprising lithium-ion battery pack and supercapacitors, has been tested by simulating a simple power splitting scheme in an electric forklift application considering a real world drive cycle. With the purpose of numerical investigation, battery and supercapacitor models in Simulink SimPowerSystems are used, induction motor parameters are estimated using data sheet values and field oriented control (FOC) technique is adopted to drive motors. Simulation results have shown that HESS could reduce stress on the battery by limiting peak and surge power demands.

A study on feasibility of wind energy production in Silivri region by using laboratory setup

In this study, suitability of several factors have been investigated for site selection and the wind energy potential of that site is analyzed in laboratory conditions. A 7.5kW wind turbine with a 1.65m wing radius that is coupled to an induction machine is modeled with a 7.5kW motor-generator couple in the laboratory and their rotational speeds are adjusted through their drives to desired levels. A power analyzer is employed to perform the measurements and the collected data is evaluated. The laboratory experiments allowed monitoring the output current, voltage, and the power of the generator under varying drive speeds that emulates the changes in the wind speeds. Based on the increased load references applied to the generator, it is observed that the current from the generator increases; however, it is observed that the generator output voltage does not vary as the same rate. The contribution of this study is mainly using wind speed data in order to calculate rotor speed data by taking into account the lab setup as basic simulation test bench.