Overview and Advancements in Electric Vehicle WPT Systems Architecture

Wireless Power Transfer (WPT) system is a rapidly evolving technology with vast potentials in consumer electronics, electric vehicles, biomedicals and smart grid applications such as Vehicle to Grid (V2G). Hence, this article is devoted to present an overview of recent progress in WPT with specific interest in magnetic resonance WPT and its system architectures such as compensation topologies, inputs and outputs, as well as coil structure. The strengths, drawbacks and applications of the basic compensations (SS, SP, PS, PP) and hybrid compensations (LCC and LCL) were presented and compared. Although primary parallel compensations perform well at low mutual inductance, they are rarely used due to large impedance and dependence of coefficient coupling on the load. Hence, the need for extra-compensations forming hybrid topologies, such as LCC, LCL, which usually choice topologies for dynamic WPT application or V2G application

A review of compensation topologies and control techniques of bidirectional wireless power transfer systems for electric vehicle applications

Owing to the constantly rising energy demand, Internal Combustion Engine (ICE)-equipped vehicles are being replaced by Electric Vehicles (EVs). The other advantage of using EVs is that the batteries can be utilised as an energy storage device to increase the penetration of renewable energy sources. Integrating EVs with the grid is one of the recent advancements in EVs using Vehicle-to-Grid (V2G) technology. A bidirectional technique enables power transfer between the grid and the EV batteries. Moreover, the Bidirectional Wireless Power Transfer (BWPT) method can support consumers in automating the power transfer process without human intervention. However, an effective BWPT requires a proper vehicle and grid coordination with reasonable control and compensation networks. Various compensation techniques have been proposed in the literature, both on the transmitter and receiver sides. Selecting suitable compensation techniques is a critical task affecting the various design parameters. In this study, the basic compensation topologies of the Series-Series (SS), Series-Parallel (SP), Parallel-Parallel (PP), Parallel-Series (SP), and hybrid compensation topology design requirements are investigated. In addition, the typical control techniques for bidirectional converters, such as Proportional-Integral-Derivative (PID), sliding mode, fuzzy logic control, model predictive, and digital control, are discussed. In addition, different switching modulation schemes, including Pulse-Width Modulation (PWM) control, PWM + Phase Shift control, Single-Phase Shift, Dual-Phase Shift, and Triple-Phase Shift methods, are discussed. The characteristics and control strategies of each are presented, concerning the typical applications. Based on the review analysis, the low-power (Level 1/Level 2) charging applications demand a simple SS compensation topology with a PID controller and a Single-Phase Shift switching method. However, for the medium- or high-power applications (Level 3/Level 4), the dual-side LCC compensation with an advanced controller and a Dual-Side Phase-Shift switching pattern is recommended.Web of Science1520art. no. 781

Heikosti kytketyn langattoman tehonsiirtojärjestelmän tehovahvistimen suunnittelu ja toteutus

The exploitation of magnetic resonance induction in wireless power transfer system where two magnetically coupled tuned resonators forms an energy transfer path is introduced. Starting from equivalent circuit of coupled LC-resonators the expression for maximum power transfer efficiency was derived and it was found that coupling factor and resonators Q values are determinant in power transfer efficiency. Class D ZVS (zero voltage switching) and Class E switch mode power amplifiers were studied and prototype power stages were designed and implemented. Both amplifiers were tested with A4WP compliant coil set at 6.78MHz operation frequency. Several performance tests were carried out and at the end amplifier topologies were compared with respect to power transfer efficiency. According to the results both amplifier topologies met the high efficiency requirement needed in wireless power transfer, even though those both have their own optimal operation conditions where maximum efficiency is achieved. As a result topology selection table was presented as a tool for designer and design guidelines concerning amplifier topology selection, PWB layout, amplifier ZVS tuning and EMI were introduced. Previously in RF engineering exclusively seen GaN FETs are breaking into area of power electronics and the interest in their excellent switching characteristics brought them also part of this work. Both amplifiers were implemented by using GaN FETs as a switching device and high performance were proved by thermal measurements and observing switching waveforms. Main characteristics of GaN FET were studied and some qualitative comparison with MOSFET introduced.Magneettista resonanssi-induktiota hyödyntävässä langattomassa tehonsiirtojärjestelmässä kaksi heikosti toisiinsa kytkettyä resonaattoria muodostavat tehonsiirtotien. Lähtien liikkeelle kytkettyjen LC-resonaattorien piirikaaviosta johdetaan lauseke tehonsiirtohyötysuhteelle ja havaitaan kytkentäkertoimen ja resonaattoreiden Q-arvojen olevan määrääviä tekijöitä tehonsiirtohyötysuhteen arvossa. Työssä suunnitellaan ja toteutetaan kytkemistekniikkaan perustuvat D ja E-luokan tehovahvistimet. Kumpikin vahvistin testataan A4WP standardin mukaisella lähetin-vastaanotin parilla 6,78 MHz toimintataajuudella. Useita suorituskyky mittauksia suoritetaan ja lopuksi vahvistin topologioiden hyötysuhde arvoja vertaillaan. Kummankin vahvistin topologian havaitaan täyttävän langattoman tehonsiirto järjestelmän korkeat hyötysuhde vaatimukset, vaikka vahvistimien optimaaliset toiminta olosuhteet eroavatkin toisistaan. Työ tarjoaa suunnittelijoille ohjeita oikean vahvistin topologian valinnassa, piirilevyn suunnittelussa, vahvistimien optimaalisesta virityksestä sekä EMI näkökohdista. Aiemmin yksinomaan radiotekniikassa käytetyt GaN FET transistorit ovat alkaneet herättää kiinnostusta myös tehoelektroniikan puolella. GaN FET kytkinkomponenttien erinomaiset kytkentäominaisuudet toivat ne myös osaksi tätä työtä. Työn molemmat vahvistimet toteutettiin GaN FET kytkimillä ja niiden erinomainen suorituskyky vahvistettiin mittauksin

Modeling and Control of a 7-Level Switched Capacitor Rectifier for Wireless Power Transfer Systems

Wireless power continues to increase in popularity for consumer device charging. Rectifier characteristics like efficiency, compactness, impedance tunability, and harmonic content make the multi-level switched capacitor rectifier (MSC) an exceptional candidate for modern WPT systems. The MSC shares the voltage conversion characteristics of a post-rectification buck-boost topology, reduces waveform distortion via its multi-level modulation scheme, demonstrates tank tunability via the phase control inherent to actively switched rectifiers, and accomplishes all this without a bulky filter inductor. In this work, the MSC WPT system operation is explained, and a loss model is constructed. A prototype system is used to validate the models, showing exceptional agreement with the predicted efficiencies. The modeled MSC efficiencies are between 96.1% and 98.0% over the experimental power range up to 20.0 W. Two significant control loops are required for the MSC to be implemented in a real system. First, the output power is regulated using the modulation of the rectifier\u27s input voltage. Second, the switching frequency of the rectifier must exactly match the WPT carrier frequency set by the inverter on the primary side. Here, a small signal discrete time model is used to construct four transfer functions relating to the output voltage. Then, four novel time-to-time transfer functions are built on top of the discrete time model to inform the frequency synchronization feedback loop. Both loops are tested and validated in isolation. Finally, the dual-loop control problem is defined, closed form equations that include loop interactions are derived, and stable wide-range dual-loop operation is demonstrated experimentally

Study of radiation-tolerant integrated circuits for space applications

Integrated Circuits in space suffer from reliability problems due to the radiative surroundings. High energy particles can ionize the semiconductor and lead to single event effects. For digital systems, the transients can upset the logic values in the storage cells which are called single event upsets, or in the combinational logic circuits which are called single event transients. While for analog systems, the transient will introduce noises and change the operating point. The influence becomes more notable in advanced technologies, where devices are more susceptive to the perturbations due to the compact layout. Recently radiation-hardened-by-design has become an effective approach compared to that of modifying semiconductor processes. Hence it is used in this thesis project. Firstly, three elaborately designed radiation-tolerant registers are implemented. Then, two built-in testing circuits are introduced. They are used to detect and count the single event upsets in the registers during high-energy particle tests. The third part is the pulse width measurement circuit, which is designed for measuring the single event transient pulse width in combinational logic circuits. According to the simulations, transient pulse width ranging from 90.6ps to 2.53ns can be effectively measured. Finally, two frequently used cross-coupled LC tank voltage-controlled oscillators are studied to compare their radiation tolerances. Simulation results show that the direct power connection and transistors working in the deep saturation mode have positive influence toward the radiation tolerance. All of the circuit designs, simulations and analyses are based on STMicroelectronics CMOS 90 nm 7M2T General Process

Near-field wireless power transfer and communication system design for corneal intraocular prosthetic device

This thesis reports the design of a novel intraocular projection device for the treatment of intractable corneal opacity, with a design emphasis on the simultaneous wireless power and data transfer system. Electronic ocular prosthetics (EOP) or artificial eyes are devices designed to deliver artificial visual stimuli to patients with blindness to partially restore their visual function. The need for wireless capabilities in EOPs arises from the highly limited physical space available for the intraocular implant devices. Early attempts at EOPs incorporated prohibitively large battery power sources and physical wire connections for the transmission of both power and information. However, one of the vital health regulations on medical implant devices involves the potential infection and inflammation caused by the implantation. Such regulations strictly prohibit the use of physical wire between the interbody and external-body components. This thesis presents a wireless power transfer (WPT) implementation that allows the battery to be kept outside of the patient’s body, significantly reducing the size of the implanted components, while still supplying energy to the implant without a signal exchange wire. The designed devices maintain the needed power and data exchange with the embedded parts while minimizing potential health complications from surgically inserted cables and bulky embedded hardware

Development of wireless charging system along with power line communication used in Electric Vehicles

Charging an Electric Vehicle wirelessly is the latest technology being developed for the electric vehicles replacing the traditional way of plugging to the supply. In this paper, authors explained how to integrate Power Line Communication along with wireless power transfer in EV. The entire system is implemented in ADS simulation software. We are adapting to magnetic resonance coupling method for wireless power transfer in EV. The overall ideology of the project is to design an innovative system which involves higher power transfer and implement smart communication system between vehicle and the grid while following the latest magnetic resonance charging standards.

Harvesting energy from non-ideal vibrations

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 147-152).Energy harvesting has drawn significant interest for its potential to power autonomous low-power applications. Vibration energy harvesting is particularly well suited to industrial condition sensing, environmental monitoring and household environments where low-level vibrations are commonly found. While significant progress has been made in making vibration harvesters more efficient, most designs are still based on a single constant vibration frequency. However, most vibration sources do not have a constant frequency nor a single harmonic. Therefore, the inability to deal with non-ideal vibration sources has become a major technological obstacle for vibration energy harvesters to be widely applicable. To advance the state of vibration energy harvesting, this thesis presents a design methodology that is capable of dealing with two major non-ideal vibration characteristics: single harmonic frequency shifting and multi-frequency/broadband excitation. This methodology includes a broad-band impedance matching theory and a power electronics architecture to implement that theory. The generalized impedance matching theory extends the well known single frequency impedance matching model to a multi-frequency impedance matching model. By connecting LC tank circuits to the harvester output, additional resonant frequencies are created thereby enabling the energy harvesting system to effectively harvest energy from multi-harmonic vibration sources. However, the required inductors in the LC tank circuits are often too large (>10 H) to be implemented with discrete components. The power electronics proposed here addresses this issue by synthesizing the tank circuits with a power factor correction (PFC) circuit. This circuit mainly consists of an H-bridge, which contains four FETs, and a control loop that turns the FETs on and off at the right time such that the load voltage and current display the characteristics of the multiple tank circuits. By using this proposed power electronics, we demonstrate dual-frequency energy harvesting from a single mechanically resonant harvester. Simulation and experimental results match well and demonstrate that the proposed power electronics is capable of implementing higher order multi-resonant energy harvesting systems. In conclusion, this thesis presents both a theoretical foundation and a power electronics architecture that enables simultaneous effective multi-frequency energy harvesting with a single mechanically resonant harvester. The tunability of the power electronics also provides the possibility of dynamic real-time tuning which is useful to track non-stationary vibration sources.by Samuel C. Chang.Ph.D

Bidirectional Electric Vehicles Service Integration in Smart Power Grid with Renewable Energy Resources

As electric vehicles (EVs) become more popular, the utility companies are forced to increase power generations in the grid. However, these EVs are capable of providing power to the grid to deliver different grid ancillary services in a concept known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V), in which the EV can serve as a load or source at the same time. These services can provide more benefits when they are integrated with Photovoltaic (PV) generation. The proper modeling, design and control for the power conversion systems that provide the optimum integration among the EVs, PV generations and grid are investigated in this thesis. The coupling between the PV generation and integration bus is accomplished through a unidirectional converter. Precise dynamic and small-signal models for the grid-connected PV power system are developed and utilized to predict the system’s performance during the different operating conditions. An advanced intelligent maximum power point tracker based on fuzzy logic control is developed and designed using a mix between the analytical model and genetic algorithm optimization. The EV is connected to the integration bus through a bidirectional inductive wireless power transfer system (BIWPTS), which allows the EV to be charged and discharged wirelessly during the long-term parking, transient stops and movement. Accurate analytical and physics-based models for the BIWPTS are developed and utilized to forecast its performance, and novel practical limitations for the active and reactive power-flow during G2V and V2G operations are stated. A comparative and assessment analysis for the different compensation topologies in the symmetrical BIWPTS was performed based on analytical, simulation and experimental data. Also, a magnetic design optimization for the double-D power pad based on finite-element analysis is achieved. The nonlinearities in the BIWPTS due to the magnetic material and the high-frequency components are investigated rely on a physics-based co-simulation platform. Also, a novel two-layer predictive power-flow controller that manages the bidirectional power-flow between the EV and grid is developed, implemented and tested. In addition, the feasibility of deploying the quasi-dynamic wireless power transfer technology on the road to charge the EV during the transient stops at the traffic signals is proven

BiCMOS Millimetre-wave low-noise amplifier

Abstract: Please refer to full text to view abstract.D.Phil. (Electrical and Electronic Engineering