This thesis entails the design and fabrication of a smartphone charger that is powered by a bicycle dynamo hub. In addition to the design and validation of the charger prototype, this thesis involves the testing and characterization of the dynamo hub power source, the design and construction of specialized test equipment, and the design and prototyping of a handlebar-mounted case for the smartphone and charging electronics. With the intention of making the device a commercial product, price, aesthetics, and marketability are of importance to the design. An appropriate description of the charger circuit is a microcontroller-based energy management system, tailored to meet strict power demands of current smartphones. The system incorporates a switched-mode power supply, lithium polymer battery, microcontroller, and specialized protection circuitry. Prototype testing confirms that the circuit meets the charging requirements of the smartphone at bicycle speeds ranging from 7 miles per hour to as high as 55 miles per hour.

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In order to increase the power density, the discontinuous conducting mode (DCM) and small inductance is adopted for high power bidirectional dc-dc converter. The DCM related current ripple is minimized with multiphase interleaved operation. The turn-off loss caused by the DCM induced high peak current is reduced by snubber capacitor. The energy stored in the capacitor needs to be discharged before device is turned on. A complementary gating signal control scheme is employed to turn on the non-active switch helping discharge the capacitor and diverting the current into the anti-paralleled diode of the active switch. This realizes the zero voltage resonant transition (ZVRT) of main switches. This scheme also eliminates the parasitic ringing in inductor current. This work proposes an inductance and snubber capacitor optimization methodology. The inductor volume index and the inductor valley current are suggested as the optimization method for small volume and the realization of ZVRT. The proposed capacitance optimization method is based on a series of experiments for minimum overall switching loss. According to the suggested design optimization, a high power density hardware prototype is constructed and tested. The experimental results are provided, and the proposed design approach is verified. In this dissertation, a general-purposed power stage model is proposed based on complementary gating signal control scheme and derived with space-state averaging method. The model features a third-order system, from which a second-order model with resistive load on one side can be derived and a first-order model with a voltage source on both sides can be derived. This model sets up a basis for the unified controller design and optimization. The Δ-type model of coupled inductor is introduced and simplified to provide a more clearly physical meaning for design and dynamic analysis. These models have been validated by the Simplis ac analysis simulation. For power flow control, a unified controller concept is proposed based on the derived general-purposed power stage model. The proposed unified controller enables smooth bidirectional current flow. Controller is implemented with digital signal processing (DSP) for experimental verification. The inductor current is selected as feedback signal in resistive load, and the output current is selected as feedback signal in battery load. Load step and power flow step control tests are conducted for resistive load and battery load separately. The results indicate that the selected sensing signal can produce an accurate and fast enough feedback signal. Experimental results show that the transition between charging and discharging is very smooth, and there is no overshoot or undershoot transient. It presents a seamless transition for bidirectional current flow. The smooth transition should be attributed to the use of the complementary gating signal control scheme and the proposed unified controller. System simulations are made, and the results are provided. The test results have a good agreement with system simulation results, and the unified controller performs as expected. / Ph. D.

This thesis deals with the design of Hybrid Energy Storage System (HESS) for Light Electric Vehicles (LEV) and EVs. More specifically, a tri-mode high-efficiency non-isolated half-bridge converter is developed for the LEV based HESS applications. A 2 kW, 100 V interleaved two-phase converter prototype was implemented. The peak efficiency of 97.5% and a minimum efficiency of 88% over the full load range are achieved. Furthermore, a power-mix optimizer utilizing the real-time Global Positioning System (GPS) data for the EV based HESS is proposed. For a specific design, it is shown that at the cost of less than 1.5% of the overall energy savings, the proposed scheme reduces the peak battery charge and discharge rates by 76% and 47%, respectively. A 30 kW bi-directional dc-dc converter is also designed and implemented for future deployment of the designed HESS into a prototype EV, known as A2B.

This thesis deals with the design of Hybrid Energy Storage System (HESS) for Light Electric Vehicles (LEV) and EVs. More specifically, a tri-mode high-efficiency non-isolated half-bridge converter is developed for the LEV based HESS applications. A 2 kW, 100 V interleaved two-phase converter prototype was implemented. The peak efficiency of 97.5% and a minimum efficiency of 88% over the full load range are achieved. Furthermore, a power-mix optimizer utilizing the real-time Global Positioning System (GPS) data for the EV based HESS is proposed. For a specific design, it is shown that at the cost of less than 1.5% of the overall energy savings, the proposed scheme reduces the peak battery charge and discharge rates by 76% and 47%, respectively. A 30 kW bi-directional dc-dc converter is also designed and implemented for future deployment of the designed HESS into a prototype EV, known as A2B.

This thesis contains a complete description of the design and implementation of a 500W transformer soldering station. This soldering station includes a half-bridge DC/DC converter with a pulse transformer. The device works with a very low voltage and extremely high output current. Therefore some parts have a special design to ensure the proper equipment function. Coaxial transformer with very low leakage inductance (nH units) is unusual. A synchronous rectifier is another special feature working with low voltage and high output current of the transformer. The finished functional prototype consists of a soldering station and a soldering adapter.

For radio frequency energy transmission, the conversion efficiency of the receiver is decisive not only for reducing sending power, but also for enabling energy transmission over long and variable distances. In this contribution, we present a passive RF-DC converter for energy harvesting at ultra-low input power at 868 MHz. The novel converter consists of a reactive matching circuit and a combined voltage multiplier and rectifier. The stored energy in the input inductor and capacitance, during the negative wave, is conveyed to the output capacitance during the positive one. Although Dickson and Villard topologies have principally comparable efficiency for multi-stage voltage multipliers, the Dickson topology reaches a better efficiency within the novel ultra-low input power converter concept. At the output stage, a low-pass filter is introduced to reduce ripple at high frequencies in order to realize a stable DC signal. The proposed rectifier enables harvesting energy at even a low input power from −40 dBm for a resistive load of 50 kΩ. It realizes a significant improvement in comparison with state of the art solutions

Ce travail concerne l’étude et la réalisation d’une architecture multicellulaire de conversion d’énergie électrique haute tension avec étage intermédiaire alternatif moyenne fréquence destinée à la traction électrique ferroviaire. L’objectif de ce travail est de diminuer la masse et le volume de l’étage de conversion alternatif-continu que l’on retrouve dans les engins de traction conçus pour circuler sur les réseaux alternatifs 25kV-50Hz ou 15kV-16Hz2/3. La recherche de gains sur l’étage de conversion alternatif-continu s’applique aussi bien sur les automotrices où l’on cherche à gagner de la place disponible pour y placer des passagers que sur les locomotives ou encore sur les motrices de TGV où l’on recherche un gain de masse étant donné que ces engins sont en limite de charge à l’essieu. Le contexte de la haute tension implique l’utilisation d’interrupteurs de forts calibres en tension pour limiter au maximum le nombre de cellules de conversions utilisées. D’un autre côté, la recherche de gains sur le transformateur nécessite une fréquence de découpage élevée, génératrice de pertes en commutation dans les interrupteurs. L’architecture de conversion retenue permet par l’association de structures duales d’obtenir des conditions de commutation douce, ce qui est favorable à une montée en fréquence avec des interrupteurs de forts calibres en tension. Le convertisseur élémentaire associe un onduleur de tension commandé au blocage et un commutateur de courant commandé à l’amorçage. Afin d’évaluer le rendement de l’architecture considérée, un prototype d’un bloc de conversion élémentaire, d’une puissance de 280 kVA, a été réalisé au laboratoire PEARL. Les interrupteurs sont réalisés sur la base de modules IGBT 6,5kV/200A. Les essais en commutation douce ont permis d’évaluer, dans des conditions de fonctionnement réelles, les pertes dans les modules IGBT. Compte tenu de ces résultats, il est possible de déterminer les limites de fonctionnement de la structure de conversion et d’effectuer un dimensionnement en considérant le compromis rendement-poids-volume pour un engin de traction donné. / This thesis concerns the study and the rating of a high voltage multicellular converter with an intermediate medium frequency stage dedicated to railway traction. The objective is to reduce the weight and the volume of the AC-DC conversion stage which is implemented in railway engines running on 25kV-50Hz or 15kV-16Hz2/3 railways. Reduction on weight and size of the AC-DC converter may be applied on multiple unit trains where the transformer causes room loss for passengers and on locomotives and high speed trains where the axle load is limited. On one hand high voltage switches are required in order to minimize the number of cells used to build the converter. On the other hand, reducing the size and the weight of the transformer requires a high switching frequency, causing high commutation losses. To achieve soft switching conditions with high voltage semiconductors, the proposed topology is based on an association of dual structures. Each elementary converter combines a controlled turn-off voltage source inverter and a controlled turn-on current source inverter. In order to estimate the efficiency of the new topology, a prototype of one elementary cell working at 280 kVA, was built at the Power Electronics Associated Research Laboratory (PEARL). The switches are standard 6.5 kV/200A IGBTs modules. Soft-switching tests, in real operating conditions, allow evaluating IGBTs and diodes switching losses. Thanks to these results, it is possible to find the structure operating limits and to size the transformer considering the trade-off between the system efficiency and the transformer weight.