New Power Converter Topology For Low Power Rotary Capacitive Power Transfer System

Since the past decade, many researchers have taken interest to investigate the capacitive power transfer (CPT) as an alternative to achieve contactless power transfer. By employing the electric field as the energy transfer medium, CPT has the advantages of the confined electric field between coupling plates, power transfer capability through metal barriers, low eddy current power losses associated with metal surroundings, as well as the potential to minimise circuit size and cost. This thesis mainly concentrates on the development of a fundamental theory of CPT system and its application for low power contactless charging. Initially, the thesis begins by analysing the Class-E resonant inverter performance to generate high frequency AC power source to drive the CPT system. Due to the sensitivity of components variation, the investigation of Class-E resonant inverter with feedback frequency controller unit is proposed to enhance the efficiency of CPT system by preserving the zero voltage switching (ZVS) condition over a longer distance. Second, the utilization of compensation network to serve as an impedance converter in order to enable efficient power transfer between two stages with non-matching impedances had been investigated. Here, mathematical analysis of the sensitivity of the system output power in respect to the load variation was introduced. Third, a Class-E combined with LCCL compensation network topology for both transmitter and receiver is proposed to provide impedance matching and hence, keeping the ZVS condition for wider load-range changes. Next, based on the proposed Class-E LCCL topology, a single plate rotary CPT system was developed to realize power transfer to the rotating load. Finally, in enhancing the capacitive coupler embedded in the rotary CPT system, the rotating capacitive coupler was upgraded with multiple plate structure approach to generate a small and compact capacitive coupler plate without the need of increasing electric field emission. This was controlled by a novel power flow control topology called cascaded Boost-Class-E. With the application of these proposed control methods, the output power of rotary CPT system could be adjusted. Overall, this thesis presents a fundamental study on CPT technology carried out by employing mathematical analysis, computer simulations, and practical experiments for validation purpose. A 10W prototype was constructed to verify the proposed circuit. The best experiment prototype of this work has demonstrated more than 90% efficiency at 2 mm working distance, which can be considered as an exceptional performance, when compared to the existing low power scale CPT system achievements. In conclusion, the research outcomes portray the feasibility and the potential of CPT as an emerging contactless power transfer solution, as well as the theory and the practical design methods that establish a solid foundation for future CPT research and development

A study in industrial robot programming

This project is concerned with learning the tec1mology and programming of servo controlled industrial robots. A Mitsubishi RV-2AJ articulated robot was used in this project. The project work is divided into two parts: In the first part of the project the author familiarized herself with the operation and programming of the robot's manipulator and controller hardware by carrying out some laboratory experiments. A set oflaboratory sheets were produced from this exercise. In the second part, the author studied the mechanics of software control of the robot. A user-defined trajectory planning routine based on the cubic spline fitting function has successfhlly been developed in this project

DC Motor Speed Control Development System (DCMSCDS)

This project is about building a low cost education aid for teaching electrical drive laboratory experiments as well as useful output load for power electronics subjects. DC Motor Speed Control Development System is used for DC motor driver and control system. This block of system only consists of the de machine and speed indicator. The controller or drive is not included, to allow the user to design and construct the drive based on the specifications defined. This is the idea of this research, to enhancing creativity of the students in laboratory activities instead of constructing a circuit by referring the lab manual or just connecting the circuit by using jumper if involving the training module. This kind of laboratory training, student would only know how use jumper without knowing the function of every components in the circuit. They will not appreciate the important reading data sheet before running the lab work. Therefore, this project will give an encouraging scenario in teaching and learning techniques and in solving problems to be more innovative and creative in learning electric drive. The student will be able to appreciate more in designing and constructing. Moreover, this education aid also can be used by PSM student is speed control research area of DC motor because of its flexibility of input and output. Not forget to mention low cost teaching aid for electric drive experiments

Simulation Study on Self-frequency Tracking Control Strategy for Inductive Power Transfer System

This paper presents a closed loop Inductive Power Transfer (IPT) system. In this work, the Phased Lock Loop control system is used to control the frequency of Class E resonant converter circuit. Furthermore, self-frequency tracking control strategy with simple detection circuit is proposed as a feedback circuit to IPT system. Through this method, the frequency drifting that is due to variation in reactive components or mutual inductive coupling can be avoided successfully. The IPT system with and without frequency tracking is analyzed at different coupling coefficient. Simulation results confirm that the Class E resonant power converter circuit with frequency tracking gives a better output result with 92% efficiency at 0.8 of coupling coefficien

Simulation-based Study of Capacitance Values Affected by Various Dielectric Materials and Distances for Low Power Wireless Power Transfer System

Capacitive Power Transfer (CPT) system is nowadays getting better attention by some of the researchers who are focusing on wireless power transfer field. This is because of the simplicity, small size, and better reaction towards EMI characteristics of the method. Furthermore, the efficiency of the CPT system is greatly influenced by the coupling capacitances which are varied by distances and permittivity values. Thus, this paper attempts to converge into the effect of several dielectric materials towards capacitance values and also the effect of the capacitive plates’ distances towards the output power. By using Class E circuit configuration and MATLAB Simulink as the simulation software, the results are then explained graphically. From those simulations, the work achieved 90.7% as highest efficiency as compared to the theoretical values

The design of an efficient class E-LCCL capacitive power transfer system through frequency tuning method

In this work, the optimum zero voltage switching (ZVS) of Class E-LCCL capacitive power transfer (CPT) was determined via frequency tuning method. Through this an efficient system can be guanranteed although there is a change in the capacitive plates distance. This study used a Class-E LCCL inverter, as it can operate at a high alternate current frequency, besides producing low switching losses and minimal power losses. Specifically, this study conducted simulations and experiments to analyse the performance of an LCCL CPT System at 1 MHz operating frequency and 24 V DC supply voltage. Using an air gap distance of 0.1 cm, the designed CPT system prototype successfully achieved an output power of 10W and an efficiency of 95.45%. This study also found that by tuning the resonant frequency of the Class E-LCCL system, the optimum ZVS can be obtained although capacitive plate distance was varied from 1-3 cm via experimental. The results of this study could benefit medical implant and portable device development, consumer electronics, and environments that involve electrical hazards

Class E ZVS Inverter Simulation for Series Resonance Mode Ultrasonic Transducer

Single-ended Class E ZVS inverter is known as higher efficiency power converter with a simple design topology. However, the efficiency of the circuit is most influenced by the variations of the connected load, especially when dealing with ultrasonic transducer. This paper presents a design of high efficiency power converter for series resonance mode ultrasonic transducer in acoustics energy transfer applications. To enhance the performance of the circuit, the tuning procedure of shunt capacitor and series inductor are delivered and as a result, 0.191 W output power is able to be transmitted successfully with 95.5% power conversion efficiency

A Modified Class-Eπ1b For Capacitive Power Transfer System

This paper exhibits the advancement of another power transfer method utilizing electric field as energy medium transfer, namely capacitive power transfer. Capacitive power transfer system has been introduced as an attractive alternative to the traditional inductive coupling method due to better electromagnetic interference performance and robustness to surrounding metallic elements. In this work, a Class-E inverter has been utilized to drive the proposed CPT system. However, the Class-E inverter is highly sensitive to its circuit parameters under the scenario of having small capacitance at the coupling plate. As a solution, a 1b matching type has been integrated with Class-E inverter to provide impedance transformation and increase coupling capacitance for a better performance. The validity of the proposed idea has been approved through a 10W experimental work. The performance of the proposed topology is broke down in term of zero voltage switching and DC-DC effectiveness. Experimental work has successfully demonstrated that the proposed system able to transfer 8.82W of power across the 1.82nF capacitive interface, operating frequency of 1MHz, with 91.2% efficiency at 0.25mm working distance