Multiphase wireless dynamic charging systems for electric vehicles

PhD ThesisElectric vehicles (EVs) have been intensively developed as an attempt to reduce carbon-dioxide emissions caused by fossil-fuel vehicles. EVs require expensive batteries and power electronics for charging and discharging the battery. Unfortunately, battery technology, such as lithium-ion batteries requires substantial improvements to effectively compete with fossil-fuel cars in price. Also, batteries are usually heavy, take up large space and still have range limitation. Wireless Dynamic Charging (WDC), while the vehicles are in motion, is seen as an alternative to overcome the drawbacks associated with batteries. Due to the continues charging when driving, batteries can become smaller as most of the traction energy comes from the grid directly. WDC is fundamentally developed based on inductive power transfer (IPT) technology, where a time-varying magnetic field is generated by transmitter coils, which are installed underneath the road surface, to wirelessly power receiver coils, that charge the EV’s battery continuously. Presently, there are several technical challenges associated with WDC, which hinders commercialization. The output power fluctuation along the driving direction is one of the most serious problems. These fluctuations cause reduction in constant energy transfer thus requiring larger batteries. Also, batteries lifetime is significantly reduced as a result of increasing internal heating. Several studies attempted to realise constant output power for WDC. However, proposed methods so far, have disadvantages such as high cost, complexity or unable to sustain constant output power throughout the charging process. The work in this thesis proposes a multiphase WDC system to simultaneously achieve constant and high output power for EV applications. The proposed WDC system utilizes multiple primary windings that guarantee a homogeneous mutual magnetic flux for the receiver along the driving direction. This results in a constant induced voltage across the receiver and hence constant output power to charge the EV battery. High output power capability is attained by using multiple transmitter windings arranged in a novel winding method. The effectiveness of the proposed system is analytically described, simulated and demonstrated experimentally using a 3-kW laboratory prototype with the three-phase transmitter. The proposed system requires only simple control, eliminates communications between the primary and secondary sides and delivers 125% higher power transfer capability compared to conventional single-phase WDC systems

Robust condition monitoring for modern power conversion

The entire US electrical grid contains assets valued at approximately $800 billion, and many of these assets are nearing the end of their design lifetimes. In addition, there is a growing dependence upon power electronics in mission-critical assets (i.e. for drives in power plants and naval ships, wind farms, and within the oil and natural-gas industries). These assets must be monitored. Diagnostic algorithms have been developed to use certain key performance indicators (KPI) to detect incipient failures in electric machines and drives. This work was designed to be operated in real-time on operational machines and drives. For example the technique can detect impending failures in both mechanical and electrical components of a motor as well as semiconductor switches in power electronic drives. When monitoring power electronic drives, one is typically interested in the failure of power semiconductors and capacitors. To detect incipient faults in IGBTs, for instance, one must be able to track KPIs such as the on-state voltage and gate charge. This is particularly challenging in drives where one must measure voltages on the order of one or two volts in the presence of significant EMI. Sensing techniques have been developed to allow these signals to be reliably acquired and transmitted to the controller. This dissertation proposes a conservative approach for condition monitoring that uses communications and cloud-based analytics for condition monitoring of power conversion assets. Some of the potential benefits include lifetime extension of assets, improved efficiency and controllability, and reductions in operating costs especially with remotely located equipment

Vehicle test report: Electric Vehicle Associates electric conversion of an AMC Pacer

Tests were performed to characterize certain parameters of the EVA Pacer and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem; i.e., the batteries, controller and motor. The tests included coastdowns to characterize the road load, and range evaluations for both cyclic and constant speed conditions. A qualitative evaluation of the vehicle's performance was made by comparing its constant speed range performance with other electric and hybrid vehicles. The Pacer performance was approximately equal to the majority of those vehicles assessed in 1977

Space station common module network topology and hardware development

Conceptual space station common module power management and distribution (SSM/PMAD) network layouts and detailed network evaluations were developed. Individual pieces of hardware to be developed for the SSM/PMAD test bed were identified. A technology assessment was developed to identify pieces of equipment requiring development effort. Equipment lists were developed from the previously selected network schematics. Additionally, functional requirements for the network equipment as well as other requirements which affected the suitability of specific items for use on the Space Station Program were identified. Assembly requirements were derived based on the SSM/PMAD developed requirements and on the selected SSM/PMAD network concepts. Basic requirements and simplified design block diagrams are included. DC remote power controllers were successfully integrated into the DC Marshall Space Flight Center breadboard. Two DC remote power controller (RPC) boards experienced mechanical failure of UES 706 stud-mounted diodes during mechanical installation of the boards into the system. These broken diodes caused input to output shorting of the RPC's. The UES 706 diodes were replaced on these RPC's which eliminated the problem. The DC RPC's as existing in the present breadboard configuration do not provide ground fault protection because the RPC was designed to only switch the hot side current. If ground fault protection were to be implemented, it would be necessary to design the system so the RPC switched both the hot and the return sides of power

Peripheral Interface Controller-Based Photovoltaic DC-DC Boost Converter

Fossil-based energy resources used in generating electricity are exhausting and finding alternative energy sources is vital for future energy demand. Photovoltaic (PV) is one of the promising renewable energy sources. However, the inconsistent characteristic of solar irradiation tends to disturb the amount of PV energy extraction. This makes the PV a non-linear power source throughout the daytime. This paper presents the prototype development of a Peripheral Interface Controller (PIC)-based photovoltaic dc-dc boost converter. In order to produce a stable dc output voltage, a closed-loop system is implemented into the converter circuit. The converter circuit was designed and simulated in PROTEUS ISIS Professional Tool and PSpiceOrCAD software environment. The control algorithm of the converter system was developed in the PIC C-Compiler software. The converter utilizes an 18V of 100W capacity PV module to generate a higher voltage for various direct current (dc) applications. With the developed and embedded control algorithm, the PIC microcontroller model PIC16F877A generates an appropriate pulse-width modulation signal to control the switching device MOSFET IRF540. Simulation results show that the controller managed to boost-up the voltage to 58.661V with minimum ripple voltage of 0.488V. The experimental results show that the converter managed to regulate the output voltage at 57.8V which is 1.47% lower than that of simulation. The result signifies the efficacy of the converter system control algorithm

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

The development of an on-chip-metering solution

Includes bibliographical references.Energy Measurements Ltd (EML), a joint venture partnership between Siemens and Spescom, manufacture prepaid electricity utility meters for both the local and international markets. Under the brand name CASHPOWER 2000, EML produces single and polyphase prepayment utility meters. Currently, these meters currently utilise a separate module for the measuring of electrical energy. In order to reduce component costs, EML proposed the energy measurement be conducted by the onboard Microcontroller Unit (MCU), a term known as On-Chip-Metering (OCM). It is envisioned that this would quickly translate in an increase in revenue. However, a major concern regarding this has been the increase in the required processor overhead. The CASHPOWER 2000 embedded MCU would be required to conduct all the present metering functionality in addition to the energy measurement. This, together with the cost analysis and compliance with the stipulated IEC1036 regulations, constitute the key criteria in determining the projects viability. This dissertation represents the investigative and development stages of a prototype algorithm and accompanying peripheral hardware as a possible solution for OCM. As part of the preliminary research, several examples of digital power and energy-measurement techniques were investigated. A comparative analysis of these was performed to facilitate the development of a unique solution based on the research conducted. This completed, a prototype was developed and preliminary testing was conducted to determine its compliance with the stipulated regulations for a class 2 meter, as per IEC1O36 specifications

Three-Phase Unfolding Based Soft DC-Link Converter Topologies for AC to DC Applications

Battery electric vehicles (BEVs) and plugin hybrid electric vehicles (PHEVs) are more efficient than internal combustion-based vehicles. Adaption of EVs will help reduce the carbon emissions produced by the transportation sector. The charging infrastructure has to grow at a rapid pace to encourage EV adaption. Installing higher capacity fast chargers will help alleviate the range anxiety of battery electric vehicle customers. More public charging stations are required for the full adaption of EVs. Utility power is distributed as ‘alternating current.’ A battery requires ‘direct current’ (DC) source to charge it. Hence a power converter that converts AC source to DC source is required to charge an electric vehicle battery. Public transportation is another sector that is adapting electric vehicles at a fast pace. These vehicles require more power to operate and hence have huge battery packs. These vehicles require ultra-high-power charger to keep the charging time reasonable. A 60 Hz stepdown transformer is required at the facility to use the power. The cost and time to install this heavy transformer will inhibit the setting up a charging station. Power converters than can connect to medium voltage directly will eliminate the need for the step-down transformer saving space and cost. Commercially available state-of-the-art fast charging converters are adapted from general purpose commercial and industrial application rectifiers. The efficiencies of these converters tend to be lower (around 94%) due to the two-stage power conversion architecture. All the power that flows from the AC utility grid to charge the battery will be processed and filtered through two power conversion stages. Due to the anticipated increase in demand, there is a renewed interest in developing power converter topologies specific to battery charging applications. The objective here is to develop cheaper and compact power converters for battery charging. This dissertation proposes an innovative quasi-single stage power converter topologies for battery charging applications and direct medium voltage connected converters. The proposed topology fundamentally can achieve higher efficiency and power density than the conventional two-stage based converters. Only one stage requires filtering and incurs power conversion losses. Control burden is usually higher for single stage topologies. Innovative control approaches are presented to simplify the control complexity

Bipropellant pulsed energy turboalternator power system development Final report, Sep. 1, 1965 - Jul. 14, 1966

Development and performance testing of bipropellant pulsed energy turboalternator and gas generator power syste

Preliminary design studies of an advanced general aviation aircraft

The preliminary design results are presented of the advanced aircraft design project. The goal was to take a revolutionary look into the design of a general aviation aircraft. Phase 1 of the project included the preliminary design of two configurations, a pusher, and a tractor. Phase 2 included the selection of only one configuration for further study. The pusher configuration was selected on the basis of performance characteristics, cabin noise, natural laminar flow, and system layouts. The design was then iterated to achieve higher levels of performance