Yazar "Uzun, Yunus" seçeneğine göre listele
Listeleniyor 1 - 20 / 23
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A neural network design for the estimation of nonlinear behavior of a magnetically-excited piezoelectric harvester(Springer, 2018) Çelik, Emre; Uzun, Yunus; Kurt, Erol; Öztürk, Nihat; Topaloğlu, NurettinAn application of an artificial neural network (ANN) has been implemented in this article to model the nonlinear relationship of the harvested electrical power of a recently developed piezoelectric pendulum with respect to its resistive load R (L) and magnetic excitation frequency f. Prediction of harvested power for a wide range is a difficult task, because it increases dramatically when f gets closer to the natural frequency f (0) of the system. The neural model of the concerned system is designed upon the basis of a standard multi-layer network with a back propagation learning algorithm. Input data, termed input patterns, to present to the network and the respective output data, termed output patterns, describing desired network output that are carefully collected from the experiment under several conditions in order to train the developed network accurately. Results have indicated that the designed ANN is an effective means for predicting the harvested power of the piezoelectric harvester as functions of R (L) and f with a root mean square error of 6.65 x 10(-3) for training and 1.40 for different test conditions. Using the proposed approach, the harvested power can be estimated reasonably without tackling the difficulty of experimental studies and complexity of analytical formulas representing the concerned system.Öğe Analysis of a novel four level flying capacitor h - bridge converter(Diponegoro University, 2018) Gülpınar, Feyzullah; Sarı, Filiz; Uzun, YunusIn this paper, a novel four-level flying capacitor inverter and its comparison with the conventional flying capacitor topology in terms of THD analysis are proposed. This new topology have some advantages over conventional one as following: The blocking voltages are the same for all switches used in the configuration, there is no need for capacitor midpoint connection and this eliminates low frequency current which circulate in dc-link capacitors, and the number of flying capacitor is reduced as compared with conventional form of it. The operation of the topology, modulation strategy, simulation results, and THD analysis for the output waveforms are presented in this paper.Öğe Design and analysis of a rotor for a 22 kW transversally laminated anisotropic synchronous reluctance motor(Kauno Technologijos Universitetas, 2021) Özdil, Ali; Uzun, YunusSubstantial increase in energy consumption in all around the world has led to researchers to need to produce electrical machines with high energy efficiency since majority of energy has been consumed at industry, especially by electrical machines. Among electrical machines, the Synchronous Reluctance Machines (SynRMs) have been preferred to investigate in recent years due to lack of Induction Machines (IMs) in terms of efficiency and high price of the Permanent Magnet Synchronous Machines (PMSMs). In this study, the Finite Element Analysis (FEA) showing the effects of phase angle of current, number of flux barriers, starting diameter of flux barriers, and ribs on machine performance of 22 kW Transversally Laminated Anisotropic (TLA)-SynRM with distributed winding have been carried out in ANSYS Electronics. The design is based on creating a novel rotor considering these rotor parameters since the utilized SynRM consists of same stator with same sized 22 kW IM. The performance of the machine has been investigated through torque, torque ripple, efficiency, saliency, and power factor. Moreover, the effect of the phase angle of the current on the machine performance and the comparison of the 22 kW-SynRM with the same sized and powered IM and with a different SynRM have been carried out in this study. This study has concluded that although the novel SynRM has high torque ripple values, it is better than the IM due to lack of copper losses of rotor and the previously utilized SynRM considering their efficiency classes. The efficiency class of novel SynRM is IE4, whereas that for utilized IM and previously created SynRM are IE1 and IE3, respectively.Öğe Design and comprehensive analyzes of a highly efficient TLA-Type synchronous reluctance machine including the effects of conductor per slot and wire size(MDPI, 2023) Özdil, Ali; Uzun, YunusConsuming energy sources and greenhouse gas emission are one of the most prominent problems of the latest century. Most of the energy consumed globally and carbon dioxide emissions originate from electric motors used in the industry. Therefore, researchers have recently focused on the production of highly efficient, eco-friendly, and low-priced machines: Synchronous Reluctance Machines. In this study, the design and comprehensive Finite Element Analysis of a TLA-SynRM including the effects of the number of conductors per slot and wire diameter directly affecting stator slot fill factor and crucial for obtaining more realistic results from experiments has been initially carried out. Moreover, power factor, saliency ratio, and efficiency of the novel SynRM are enhanced by utilizing a fine-tuning process based on d- and q-axes flux paths. Additionally, the layer structure of the initial design is changed to a double-layer structure to improve the performance of the machine in the fine-tuning process. In the final step of this study, the machine has been manufactured, and experiments have been accomplished. This study has concluded that the novel SynRM have low torque ripple, high power factor, saliency ratio, and efficiency, whose value is within the range of IE5 efficiency class.Öğe Design and implementation of a new contactless triple piezoelectrics wind energy harvester(Pergamon-Elsevıer Scıence Ltd, 2017) Kurt, Erol; Cottone, Francesco; Uzun, Yunus; Orfei, Francesco; Mattarelli, Maurizio; Özhan, DavutThe features of the new designed and constructed harvester are examined. The harvested power of three piezoelectric layers having different masses (i.e. different natural frequencies) has been explored. These layers have the same length around the harvester body, whereas a permanent magnet (PM) attached to the shaft rotates by low speed wind and this PM repels these three piezoelectric layers with a 120 phase shift. Since PM and the PMs located to the tip of the layers do not contact, this system improves the lifetime of the harvester. The measured harvested power in the low wind speeds (i.e. 1.75 m/s) is of the order of 0.2 mu W. The waveform includes many subharmonic and superharmonic components, hence the total harmonic distortion (THD) is found around 130%, which is fairly high due to nonlinear effects. Although the system shows an high THD, the 20% of the signal can be rectified and stored in the capacitor for the use of harvested energy. A scenario has also been created for a resistive load of R-L, =1 M Omega and 100 k Omega for various wind speeds and it has been proven that the harvester can feed the load at even lower wind speeds. In addition, extra power beyond the usage of the load can be stored into the capacitor. The proposed harvester and its rectifying unit can be a good solution for the energy conversion procedures of low-power required machines. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Design and simulation of a new dual-band RF energy harvester with high efficiency(Institute of Electrical and Electronics Engineers Inc., 2015) Uzun, Yunus; Kurt, ErolIn recent years, it is one of the biggest disadvantages of wireless sensors have vital importance that they are supplied by batteries. It is possible to overcome this deficiency by RF energy harvesting systems. In this work, the system generating electrical energy efficiently from two different RF signals have different frequencies is presented. Compared with conventional single frequency RF energy harvester, with the proposed dual band RF energy harvester, an increase is achieved 39% and 78% for 575 MHz and 900 MHz input frequencies at 0 dBm signal level, respectively. In a wide range of frequencies in the range of 400 MHz to 1000 MHz, the efficiency is obtained over 50% from the proposed system. Thus, the system can be used efficiently in an environment including any one or more DTV and GSM signal. The proposed circuit can be used effectively on the RF signals have the level of more than-15 and-10 dBm. © 2015 IEEE.Öğe Design and speed control of SynRM using cascade PID controller with PSO algorithm(Diponegoro University Indonesia - Center of Biomass and Renewable Energy (CBIORE), 2020) Alkhafaji, Mohammed Ayad; Uzun, YunusIn recent years, the variable speed motor drive is supported over a fixed speed motor drive as per essentialness safeguarding, speed or position control and improvement of transient response characteristics. The aim of any speed controller is to take main signal that represent the reference speed and to drive the framework at that reference speed. This paper exhibits the design, simulation and control of synchronous reluctance motor (SynRM). In addition, the motor speed is controlled by utilizing a conventional PID controller that has been used from the cascaded structure. The Particle Swarm Optimization (PSO) was used to find the best parameters of the PID controller. Lead-Lag controller presents from the cascaded controller as the following period of control. The Space vector pulse width modulation (SVPWM) plot has been proposed to control the motor and make the motor work with no rotor confine contingent upon the info parameters that utilization in the simulation. An examination between both of PID tuned and PSO tuned controller affirms that the PSO gives dazzling control highlights to the motor speed and have an edge over the physically changing controller. Thus, this paper present investigation and simulation for the most precise procedures to control the speed reaction and torque reaction of synchronous reluctance motor (SynRM).Öğe Design and ımplementation of RF energy harvesting system for low-power electronic devices(Springer, 2016) Uzun, YunusRadio frequency (RF) energy harvester systems are a good alternative for energizing of low-power electronics devices. In this work, an RF energy harvester is presented to obtain energy from Global System for Mobile Communications (GSM) 900 MHz signals. The energy harvester, consisting of a two-stage Dickson voltage multiplier circuit and L-type impedance matching circuits, was designed, simulated, fabricated and tested experimentally in terms of its performance. Simulation and experimental works were carried out for various input power levels, load resistances and input frequencies. Both simulation and experimental works have been carried out for this frequency band. An efficiency of 45% is obtained from the system at 0 dBm input power level using the impedance matching circuit. This corresponds to the power of 450 lW and this value is sufficient for many low-power devices. The most important parameters affecting the efficiency of the RF energy harvester are the input power level, frequency band, impedance matching and voltage multiplier circuits, load resistance and the selection of diodes. RF energy harvester designs should be optimized in terms of these parameters.Öğe Design of an efficient triple band RF energy harvester(Applied Computational Electromagnetics Society (ACES), 2015) Uzun, YunusIn this paper, a new triple band RF energy harvester, considering all the influential parameters, is designed by using Advanced Design System (ADS) simulation software. The most important problem in the RF energy harvesters is low system efficiency. Another problem is that these circuits work on narrow RF bands. The proposed design is found to be much efficient with its current form and provide broadband working frequencies. The output power values and efficiencies of each circuit have been obtained from the software by varying input RF power, load resistance and the number of stages in voltage multiplier at DTV 575 MHz, GSM 900 MHz and WiFi 2.45 GHz frequencies. Thereby a triple band RF energy harvester is proposed for higher efficiency. The system efficiencies for this input power level are obtained about 55% at 575 MHz, 45% at 900 MHz, 30% at 2.45 GHz. The average efficiency is found to be 43% for the individual systems. However, the system efficiency is 68% in the proposed triple band RF energy harvester. This corresponds to an increase rate of 58% for the efficiency. Furthermore, thanks to the proposed RF energy harvester, the efficiencies are increased significantly in cases which only one or two RF signals exist. © 2015 ACES.Öğe Design of broadband RF-DC converter(Institute of Electrical and Electronics Engineers Inc., 2016) Dursun, Bekir; Uzun, YunusAlmost all of the wireless devices are supplied by chemical batteries. These batteries have a number of disadvantages. In this study, a broadband RF energy harvester was designed to providing the use of wireless devices without batteries or increasing battery life. The system is designed to work between 500 MHz and 900 MHz. Thus, the proposed system can be obtained electrical energy from both DTV and GSM signals at the same time. The system efficiency which is mentioned above frequencies ranges is close to 80% for 0 dBm input power level. © 2016 IEEE.Öğe Effects of nonlinearities in a magneto-piezoelectric system(Institute of Electrical and Electronics Engineers Inc., 2014) Kurt, Erol; Uzun, YunusThis paper focuses on the theoretical and experimental analyzes on the dynamics of a magneto-piezoelectric pendulum system under the magnetic excitation. Initially, it handles the theoretical modelling of the problem including the mechanical, magnetic and electrical terms of the system. The theoretical formulation of the pendulum system is realized based on the experimental parameters. Then, a detailed experimental survey has been carried out for the system parameters, namely the magnetic field frequency f and amplitude V (i.e. proportional to the amplitude of the field). In the last part, the nonlinear patterns from the theoretical and experimental studies are discussed. It will be pointed out that the periodic magnetic flux can cause different responses in the magneto-piezoelectic system from regular dynamics to chaotic one. Phase space constructions, Poincare sections, FFTs and THDs are determined for certain parameter sets. A sample harvester application of the system will also be introduced at the end of the paper. © 2014 IEEE.Öğe Experimental and theoretical explorations on the buckling piezoelectric layer under magnetic excitation(Springer, 2017) Çelik, Kayhan; Kurt, Erol; Uzun, YunusIn the present study, experimental and theoretical explorations on the buckling features of a wind energy harvester have been performed. The harvester consists of a piezoelectric layer, which has a certain stiffness and voltage conversion rate. A blade rotates on a shaft carrying a magnet and sweeps the tip of the layer causing a serial buckling effect resulting in energy generation. Since the modeling of the buckling under a magnetic strength includes nonlinear terms over displacements, one requires a detailed study on the characteristics of buckling phenomena. It has been proven that the piezoelectric beam having the magnet at its tip can produce regular and chaotic dynamics for different frequencies (i.e. the rotation speed). In addition, there exist a number of quasi-periodic regions on the parameter space. The overall result indicates that the large area of complicated dynamics requires a detailed study in order to stabilize the position and velocity of the layer tip, thereby a much stabilized energy conversion from mechanical to electrical can be obtained. The present survey on the dynamics of the harvester is a new study and is considered as a two-parameter diagram [i.e. the wind speed (frequency) and magnetic strength]. Mainly, single-, double-, triple- and quadruple-type phase space portraits have been observed and the ripples on the maximal and minimal values of the beam velocity have been observed for certain rotation speeds. These results can be used in order to stabilize the harvester in terms of the reduction of total harmonic distortion in the generated waveform.Öğe Explorations of displacement and velocity nonlinearities and their effects to power of a magnetically-excited piezoelectric pendulum(Elsevier Science Sa, 2015) Uzun, Yunus; Kurt, Erol; Kurt, H. HilalThis paper explores the relation of the nonlinearities of displacement and velocity dynamics with the power of a piezoelectric pendulum under a periodic magnetic excitation. Initially, the theoretical formulation including the mechanical, magnetic and electrical terms is realized. Then a simulation study has been done by using the theoretical formulation based on the experimental parameters. Then, a detailed experimental survey has been carried out for some representative system parameters. Results of simulation based on the proposed model are presented and compared with the experimental results. It is observed that the periodic magnetic flux can cause different responses from regular dynamics to chaotic one. Phase space constructions, Poincare sections and FFTs are determined on parameter sets including the excitation frequency f and amplitude U-c of electromagnet. It is proven that the periodic magnetic flux exerts high frequency velocity fluctuations nearby the minimal and maximal values. While the displacement of the tip exhibits a harmonic fluctuation, FFFs prove the high frequency responses in addition to the main frequency. When f differs from the natural frequency of the system f(0), the responses become chaotic. It is proven that lower and higher frequency fluctuations in displacement and velocity, which are different from f(0) decrease the electrical power harvested by the piezoelectric pendulum. However, in the case of rms values of displacement/velocity, the harvested power is perfectly proportional to the rms values. Therefore, useful relations between power and rms values of displacement/velocity have been determined for the estimation of power output in such systems for the first time. The piezoelectric pendulum harvests much energy when f is closed to f(0) and the distance to the magnetic device should be closer in order to decrease the nonlinearities in displacement and velocity. (C) 2015 Elsevier B.V. All rights reserved.Öğe High accuracy gender determination using the egg shape index(Nature Research, 2023) Kayadan, Muhammed; Uzun, YunusSince only female chicks are used in layer hens, usually hatched male chicks are killed. It is estimated that around 7 billion chicks per year are killed immediately after hatching. In addition to being unethical, this situation also causes great financial losses. Sex determination in chicks can be done before or after hatching. Of course, determinations made before hatching are more advantageous, but the prediction rate is relatively low. The morphology of an egg is expressed in terms of the Shape Index (SI), which is the ratio of the short diameter to the long diameter. In this study, male and female chicks were predicted by using the shape index of the eggs using the RUSBoost Classifier using Shape Index. Although SI varied according to the egg type, a significant correlation (r = 0.78) was observed between chick sex and SI. Therefore, it was possible to estimate gender by utilizing SI in chickens, even if the accuracy of classification was not as high as in ducks. Besides the SI, mass, short axis, long axis, ovality, volume, eccentricity parameters were obtained and used for the results. With this features, females classified with 80% and males classified 81% correctly. The model predictions were applied to the probability of female chick hatching equation from the previous studies, 71% of the estimations were correctly classified according to this equation.With this work, around 80% of accurate predictions were made. In this case, killing 5.65 billion chicks can be prevented. Likewise, many eggs are not wasted. 1.13 billion USD loss can be prevented.Öğe Implementation of a new contactless piezoelectric wind energy harvester to a wireless weather station(Kauno Technologijos Universitetas, 2014) Uzun, Yunus; Demirbaş, S.; Kurt, E.A newcontactless piezoelectric (PZT) wind energy harvester is constructed and a feasibility study on its power generationmechanism is carried out for a wireless weather station. The new harvester has a magnetic unit enabling to vibrate aPZT layer in a contactless manner. The poles of magnets are oriented in such a way that the tip of the layer is always repelled, when wind rotates the harvester shaft. Therefore the produced magnetic force exerts mechanical bucklings on the layer and this effect produces electricity. After one-year operation, it is clarified that an averaged power of 20 mu W-60 mu W can be obtained monthly for the feeding of the station. These results prove that 5 %-18 % of the consumed power of wireless station can be generated by the harvester depending on the wind regime in the region.Öğe Mitigation of high harmonicity and design of a battery charger for a new piezoelectric wind energy harvester(Elsevier Science Sa, 2018) Bouzelata, Yahia; Kurt, Erol; Uzun, Yunus; Chenni, RachidA new piezoelectric wind energy harvester (PWEH) implementation and its power conversion system design have been studied. The new PWEH is a portable, economic, easy-mounted, and contactless machine exerting the elastic piezoelectric layers with permanent magnets (PMs). Although a single piezoelectric layer has an ideal sinusoidal waveform from its output terminals, the combined rotating system having multiple layers give complicated responses due to the electromechanical damping, high frequency mechanical vibrations and electromagnetic nonlinearities. In the current work, for instance, three layers generate three different waveforms with high harmonics. Thus, the output waveforms of such multiple layer low power-scale systems require special attention to gain the maximal power from such low scale harvesters. Indeed, electrical power generation from complicated voltage waveforms and charging efficiency have become main tasks for those low power systems. The proposed rectifier is joined to a capacitor-inductor output filter to ensure high quality DC - bus voltage by ripple mitigation function. An effective control strategy is also carried out for the voltage - mode control (VMC) method in order to control the DC-DC buck converter in such a way that it may guarantee a smooth output DC voltage. Then the later can be applied to charge storage unit such as a lead-acid type electrochemical battery for the future numerous low power applications. The proposed circuitry is successful to mitigate the harmonics of the voltage waveforms from the terminals of three piezoelectric layers with high THD values (i.e. 169.16%, 51.75% and 42.64%). In addition, the proposed PWEH has an ability to charge the battery with a stable output rectified voltage at 40V by enabling a linear increase in the State-Of-Charge (SOC) from 0% to 18% after 4 s till the battery is fully charged.Öğe Modeling and Simulation of A Photovoltaic Cell Module Controlled with Nonlinear Autoregressive Moving Average-L2 Controller(Institute of Electrical and Electronics Engineers Inc., 2020) Alkhafaji, Mohammed Ayad; Uzun, YunusThe photovoltaic cells are deemed one of the most important modern sources of renewable energy due to its direct dependence on solar energy, its low maintenance, and environmental protection. These characteristics led many specialists to study and develop this type of renewable energy. This research paper includes simulations for the design of single-diodes solar cells under the influence of different temperatures and saturation conditions to demonstrate the efficacy of the solar cell. It is also known that the solar cell must be linked to a power controller and here it will be used as an artificial neural network (ANN) technology which is the nonlinear autoregressive moving average (NARMA) by using MATLAB program to control the output power of the PV cell. Hence, the simulation results will show the comparison with and without using the NARMA-L2 controller as a maximum power point tracking (MPPT)Öğe Modeling, analysis and simulation of a high-efficiency battery control system(Tech Science Press, 2023) Alkhafaji, Mohammed Ayad; Uzun, YunusThis paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage system. The three-phase half-controlled rectifier has been designed to control and convert the AC power into DC power. In addition, two types of direct current converters have been used in this paper which are a buck and bidirectional DC/DC converters. These systems adjust the output voltage to be lower or higher than the input voltage. In the buck converters, the main switch operates in conduction or cut-off mode and is triggered by a Pulse-Width Modulated (PWM) signal. The output and input voltage levels ratio are used to calculate the PWM signal’s duty cycle. Therefore, the duty cycle indicates the operation mode of the converter in steady-state operation. In this study, we analyze and control of a buck converter with the PWM signal. Besides, the bidirectional DC/DC converter has been achieved and optimized by PI control methods to control the battery charging and discharging modes. The simulation has been applied via the Matlab/Simulink environment. The results show the activity of each part of the designed circuits starting from the converters and the battery control system in charge and discharge modes.Öğe Modelling and simulation of a propulsion electric vehicle system(Aksaray Üniversitesi Fen Bilimleri Enstitüsü, 2019) Ayad Radhi Alkhafaji, Mohammed; Uzun, YunusElektrikli Araçlar, enerji kaynağı olarak benzin yerine elektriğinin kullanılması bakımından arabaların gelişiminde bilimsel bir devrimdir. Global ısınma artışı, çevre kirliliği ve petrol üretimindeki azalma elektrikli araçları bu problemlerin üstesinden gelmek için mükemmel bir seçenek haline getirmiştir. Elektrikli araçların temel amaçları sağlam yapı, daha az bakım ve daha düşük enerji tüketimidir. Sürücü sistem, lektrikli araçların omurgasını oluşturduğu için bu özelliklerin her biri sürücü sisteminden kaynaklanmaktadır. Bu tez çalışmasında, aracı çalıştırmak amacıyla kullanılan iki adet eş zamanlı relüktans motor (SynRM) bulunmaktadır. Bu sistemde, DA batarya gerilimini üç fazlı AC gerilime dönüştürerek elektrik motorunu beslemek amacıyla gerilim kaynağı için uzay vektör darbe genişlik modülasyonlu dönüştürücü (VS-SVPWMI) kullanılmıştır. ARM hızını ayarlamak için, optimize edilmiş kademeli PID denetleyici kullanılmıştır. Denetleyici için en uygun parametre değerine ulaşmak amacıyla Parçacık Sürü Optimizasyonu (PSO) uygulanmıştır. Elektronik diferansiyel denetleyici (EDD) ve elektrikli araç sistemi modeli benzetimi yapılmıştır. EDD, çeşitli işlem ve yol şartlarında, elektrikli aracın performans dengesini düzenlemektedir. Önerilen elektrikli araç her bir sürüş biçimi için farklı yol şartlarında kararlı ve uygun bir performans sağlamaktadır. Bu çalışmada, itme sürüşlü elektrikli aracı kontrol etmek için Matlab/Simulink programı kullanılmıştır.Öğe Nonlinear problems in piezoelectric harvesters under magnetic field(Springer International Publishing AG, 2017) Kurt, Erol; Uzun, Yunus; Bizon, N; Tabatabaei, NM; Blaabjerg, F; Kurt, EThis chapter focuses on the nonlinear problems in the piezoelectric harvester systems under the magnetic field. In this manner, the chapter initially mentions an introductory section on the studies of piezoelectric harvester dynamics. After the introductory section, the basic properties of the piezoelectric systems and their energy harvester applications will be presented. Since the harvesters have a complicated structure under the magnetic field, the electromagnetic design, modeling and algebraic studies of a novel harvester study will be pointed out. After the presentation of a theoretical outline on the harvester systems, the experimental setups will be explained in detail. Thus, a complete picture of the problem will be produced in order to sustain a comparable study on the theory and experiment. The main dynamic quantities such as displacement and velocity of the vibrating piezoelectric layer as function of the system parameters will be explored. According to results, the effect of periodic magnetic flux can give varieties of responses from regular dynamics to chaotic one. Phase space constructions, Poincare sections and FFTs are evaluated depending on the parameter sets including the excitation frequency f, amplitude Uc of electromagnet and the distance d. It is proven that the periodic magnetic flux can exert high frequency velocity fluctuations nearby the minimal and maximal values of the velocity, whereas the situation differs for the position. Therefore it will be pointed out that the magnetic field mostly governs the velocity by yielding complicated vibrations. According to the detailed analyses, the FFTs prove the high frequency responses in addition to the main frequency. When f differs from the natural frequency of the system f(0), the responses become chaotic. It is proven that lower and higher frequency fluctuations in displacement and velocity, which are different from f(0) decrease the electrical power harvested by the piezoelectric pendulum. Indeed, it is remarkable to get a relation between the rms values of displacement/velocity and the harvested power according to the measurements. Thus this relation can be used to estimate the power output in harvester systems. The piezoelectric harvester generates much energy when f is closed to f(0) and the distance to the magnetic device should be closer in order to decrease the nonlinearities in displacement and velocity. The pendulum-like harvesters as the most preferable ones can be applied to many devices or units as a power source. The maximal power for these magnetically-excited structures can be estimated by the system parameters. At the end of the chapter, the recent techniques of maximal power point tracking (MPPT) and proposed controller units are explained for the piezoelectric harvester systems in order to optimize the harvested power.
