This thesis shows the implementation of a novel control scheme DC-DC converter. The converter is a phase-shifted full-bridge PWM converter that is designed to operate as a front stage of a power conversion system where the input is a variable low voltage high current source. The converter is designed to step-up the low voltage input to an acceptable level that can be inverted to a 120/240 VAC 60Hz voltage for residential power. A DSP based adaptive control model is developed, taking into account line variations introduced by the input source while providing very good load dynamics for the converter in both discontinuous and continuous conduction modes. The adaptive controller is implemented using two voltage sensors that read the input and the output voltages of the converter. The controller's bandwidth is comparable to current mode control, without the need for an expensive current sensor, yet providing the noise immunity seen in voltage mode controllers. The intended input source was a fuel cell but in its absence a DC supply is utilized instead. The system is simulated for both discontinuous and continuous conduction modes and implemented and demonstrated for the continuous conduction mode. The test results are shown to match the simulation results very closely. / Master of Science

The EU has proposed an ambitious goal to achieve widespread E-mobility in both the electrical and commercial sectors. To accomplish this, a substantial number of DC fast-charging stations must be built. These power converters, installed in the DC fast-charging stations (DCFC), differ from traditional DCDC converters as they exhibit high power density, reaching tens of kilowatts. In contrast to traditional non-isolated power converters, isolated power converters offer ideal galvanic isolation, providing protection to both the local power grid and electric vehicles. Among the DC power converters designed for industrial applications, the LLC resonant converters and DAB converters (Dual Active Bridge) have gained significant popularity. When compared to LLC converters, DAB converters demonstrate a more flexible input and output power range, as well as a higher power density. Considering these advantages, a 10kW bidirectional DAB power converter has been designed for the purpose of fulfilling the requirements of this thesis project. The thesis is organized into four distinct parts. The first part focuses on conducting a comprehensive literature review to explore the challenges prevalent in the current electrical field. Various DC-DC topologies are compared based on different factors, including component analysis, controllability, safety considerations, and cost-effectiveness. By examining these aspects, potential solutions for Electric Vehicles (EVs) are identified. In the second part, a specific DC-DC converter with a power rating of 10kW is chosen, utilizing the DAB (Dual Active Bridge) topology. The selection is based on the analysis conducted in the literature review. The thesis delves into the issues and technical challenges associated with this choice, such as reactive power, peak current, zero-voltage switching (ZVS), and phase shift modulation. These topics are thoroughly explored and discussed within the literature study. The second part of the thesis involves the establishment of a DAB model, incorporating mathematical equations and physical derivations. This modeling and design section discusses the energy conversion process, starting from fundamental physical formulas and extending to the overall system setup. Utilizing the proposed model, a control method called SPS (Single Phase Shift) modulation is implemented in the circuit to achieve closed-loop control. Within this part, the relationship between current, voltage, and output power is derived and utilized for the design of a PI closed controller. To address challenges associated with SPS control, such as reactive power elimination and peak current suppression, an EPS (Enhanced Phase Shift) control scheme is introduced. The EPS control scheme not only fulfills the basic requirement of power transfer but also optimizes the system’s overall efficiency. In the third part of the thesis, a simulation is developed to validate the accuracy of the proposed DAB model and control methods. Simulations are implemented using Simulink, a widely used software for dynamic system modeling and simulation. Various aspects of the system are evaluated through the simulation, including the leakage inductor current, voltage waveforms on both the primary and secondary sides and output power. These parameters are plotted and analyzed to assess the performance of the DAB model and control methods. Additionally, loss and efficiency analyses are conducted using PLECS, a simulation platform that specializes in power electronics systems. By inputting the datasheet information of the switches and transformer, PLECS enables the evaluation of losses and efficiency within the system. This analysis provides valuable insights into the performance and energy efficiency of the proposed DAB-based converter. In the final part of the thesis, conclusions are drawn based on the theoretical findings and simulation results obtained throughout the study. These conclusions reflect the overall outcomes and implications of the research conducted. Furthermore, the future work section outlines the tasks that remain unfinished or areas that can be explored in subsequent studies. This section serves as a guide for future researchers, highlighting potential directions for further investigation and improvement in the field of DAB-based DC-DC converters for E-mobility applications. By presenting the conclusions and future work, the thesis provides a comprehensive summary of the research conducted, its contributions, and potential avenues for future research and development. / EU har föreslagit ett ambitiöst mål för att uppnå utbredd e-mobilitet inom både den elektriska och kommersiella sektorn. För att åstadkomma detta måste ett stort antal DC snabbladdningsstationer byggas. Dessa effektomvandlare, installerade i DC-snabbladdningsstationerna (DCFC), skiljer sig från traditionella DC-DC-omvandlare eftersom de uppvisar hög effekttäthet och når tiotals kilowatt. I motsats till traditionella icke-isolerade kraftomvandlare erbjuder isolerade kraftomvandlare idealisk galvanisk isolering, vilket ger skydd för både det lokala elnätet och elfordon. Bland likströmsomvandlarna som är designade för industriella applikationer har LLC-resonantomvandlarna och DABomvandlarna (Dual Active Bridge) vunnit betydande popularitet. Jämfört med LLC-omvandlare uppvisar DAB-omvandlare ett mer flexibelt in- och uteffektområde, såväl som en högre effekttäthet. Med tanke på dessa fördelar har en 10kW dubbelriktad DAB-effektomvandlare designats för att uppfylla kraven i detta examensarbete. Avhandlingen är organiserad i fyra distinkta delar. Den första delen fokuserar på att genomföra en omfattande litteraturgenomgång för att utforska de utmaningar som råder inom det nuvarande elektriska området. Olika DCDC-topologier jämförs baserat på olika faktorer, inklusive komponentanalys, kontrollerbarhet, säkerhetsöverväganden och kostnadseffektivitet. Genom att undersöka dessa aspekter identifieras potentiella lösningar för elektriska fordon (EV). I den andra delen väljs en specifik DC-DC-omvandlare med en märkeffekt på 10kW, som använder DAB-topologin (Dual Active Bridge). Urvalet baseras på den analys som gjorts i litteraturöversikten. Avhandlingen fördjupar sig i de problem och tekniska utmaningar som är förknippade med detta val, såsom reaktiv effekt, toppström, nollspänningsomkoppling (ZVS) och fasskiftsmodulering. Dessa ämnen utforskas och diskuteras grundligt inom litteraturstudien. Den andra delen av examensarbetet omfattar upprättandet av en DAB-modell, innefattande matematiska ekvationer och fysiska härledningar. Det här avsnittet om modellering och design diskuterar energiomvandlingsprocessen, med start från grundläggande fysiska formler och sträcker sig till den övergripande systemuppställningen. Genom att använda den föreslagna modellen implementeras en styrmetod som kallas SPS-modulering (Single Phase Shift) i kretsen för att uppnå sluten-loop-styrning. Inom denna del härleds förhållandet mellan ström, spänning och uteffekt och används för konstruktionen av en sluten PI-regulator. För att ta itu med utmaningar förknippade med SPS-kontroll, såsom eliminering av reaktiv effekt och undertryckning av toppström, introduceras ett EPS-kontrollschema (Enhanced Phase Shift). EPS-kontrollsystemet uppfyller inte bara det grundläggande kravet på kraftöverföring utan optimerar också systemets totala effektivitet. I den tredje delen av avhandlingen utvecklas en simulering för att validera noggrannheten hos den föreslagna DAB-modellen och styrmetoderna. Simuleringar implementeras med Simulink, en mycket använd programvara för dynamisk systemmodellering och simulering. Olika aspekter av systemet utvärderas genom simuleringen, inklusive läckans induktorström, spänningsvågformer på både primär- och sekundärsidan och uteffekt. Dessa parametrar plottas och analyseras för att bedöma prestandan hos DABmodellen och styrmetoderna. Dessutom genomförs förlust- och effektivitetsanalyser med hjälp av PLECS, en simuleringsplattform som är specialiserad på kraftelektroniksystem. Genom att mata in databladsinformationen för switcharna och transformatorn, möjliggör PLECS utvärdering av förluster och effektivitet i systemet. Denna analys ger värdefulla insikter om prestandan och energieffektiviteten hos den föreslagna DAB-baserade omvandlaren. I den sista delen av uppsatsen dras slutsatser baserat på de teoretiska fynden och simuleringsresultat som erhållits genom studien. Dessa slutsatser speglar de övergripande resultaten och konsekvenserna av den genomförda forskningen. Vidare skisserar det framtida arbetsavsnittet de uppgifter som förblir oavslutade eller områden som kan utforskas i efterföljande studier. Det här avsnittet fungerar som en guide för framtida forskare, och lyfter fram potentiella riktningar för ytterligare undersökningar och förbättringar inom området DAB-baserade DC-DC-omvandlare för e-mobilitetstillämpningar. Genom att presentera slutsatserna och det framtida arbetet ger avhandlingen en omfattande sammanfattning av den forskning som bedrivs, dess bidrag och potentiella vägar för framtida forskning och utveckling.

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In this thesis, a new approach for single-stage power factor correction converters is proposed to increase their power ratings to be in the multiple kilowatts levels. The proposed techniques are based on the utilization of modified three-level resonant converter topologies. These topologies provide low component stresses, high frequency operation, zero voltage switching, applicability under a wide range of input and output conditions as well as added control flexibility. The proposed control algorithms are based on a combination of variable frequency and asymmetrical pulse width modulation control or variable frequency and phase shift modulation control. In either case, the variable frequency control is used to tightly regulate the output voltage, whereas, pulse width or phase shift modulation is used to regulate the dc-bus voltage as well as the input power factor. New converter topologies, their operation and steady state and dynamic analyses are presented in details. A modelling approach based on average multiple frequency methods is also proposed. This approach leads to the development of a full order state space model with the two control variables explicitly separated allowing a better controller design. The model can be used either at high level of detail expressing the non-linearities of the system or it can readily be simplified to a linear decoupled model for approximate solutions. Finally, a discrete time controller for the proposed converters, which is suitable for FPGA implementation, is presented. Analytical, simulation and experimental results are provided to verify the proposed concepts. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2008-01-30 14:28:15.725

Orientador: Carlos Alberto Canesin / Resumo: Esta tese apresenta uma forma inédita para o carregamento de veículos elétricos (VE) puros em movimento, sem fios e sem acoplamentos mecânicos (dynamic Wireless Power Transfer - dynamic WPT), considerando a transferência indutiva de energia (Induced Power Transfer - IPT), a partir de uma proposta sem sensores (WPT sensorless), combinando um arranjo de elementos transmissores, especialmente desenvolvidos para um estudo de caso. A estrutura de potência emprega um conversor ressonante LLCC série-paralelo operando em modo contínuo com modulação com frequência fixa e deslocamento de fase, com controle realimentado indiretamente para a corrente de saída. Além da metodologia utilizada para a proposta deste trabalho, o texto apresenta um projeto de carregamento estático compatível com o sistema de carregamento dinâmico e, também, uma comparação entre possíveis estruturas ressonantes de terceira e quarta ordens compatíveis com os elementos IPT, apresentando-se as vantagens e as desvantagens para cada estrutura. O carregador dinâmico foi aplicado experimentalmente para um veículo elétrico (VE) puro, em pequena escala de potência (mini baja elétrico), constituído por oito elementos IPTs associados em série como emissor, resultando em um acoplamento mútuo constante para o receptor IPT no VE por uma extensão de 1150 mm, a uma distância entre emissor e receptor, de 35 mm. Os resultados experimentais obtidos apresentam elevado rendimento médio (86,4 %) para o processo de transferência de po... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This thesis proposes a novel design to pure electrical vehicle (EV) dynamic charging electrical contactless and without mechanical coupling (dynamic Wireless Power Transfer - dynamic WPT), considering the induced power transfer, by a propose WPT sensorless, combining a transmitter element arrangement particularly designed for this study case. The power structure uses a LLCC series-parellel resonant converter, in continuous conduction mode with phase shift modulation and fixed frequency, applying a feedback indirect control for the output current. In addition to methodology in the present proposal, this paper shows a static wireless power transfer project works with the dynamic charging, and also a potential structure comparation of third and fourth order resonant compatible with the IPT elements, showing the advantages and disadvantages for each resonant tank. The dynamic charging is presently being piloted in a pure electrical vehicle, in small scale power (mini electric baja), it is made up of eight IPT elements in series association as emitter, resulting in a constant mutual coupling with IPT receiver in the EV, by a range of 1150 mm, with a distance between emitter and receiver of 35 mm. The experimental results obtained show a high average efficiency (86.4%) for the wireless power transfer process over the entire length of the loader, for the nominal input power condition of 1300 W. / Doutor