The main goal of this Electrical Engineering Bachelor project is to build a solar-power system for a quad-copter that will extend its battery life or rather its flight time. The complete system is comprised of a PV system (PV), a micro-controller (MC) and a DC/DC converter (DC) which was mounted onto the drone. On each subsystem, a separate thesis was written and this paper serves as a general yet complete overview of the design process, simulations and test results of a fully functioning solar drone with the theses attached as appendices for reference. The original (optimistic) aim of an extension of at least 25% of the battery lifetime was set by our supervisors. For the PV part SunPower C60 IBC cells were used (no specific selection was done) together with a (borrowed) custom-built drone (not built by this team, it was borrowed from another research group) as a starting point. After analysing the limitations of the drone and the cells, multiple configurations were designed and a mathematical model that determines power usage, energy costs per solar cell and the optimum amount of cells was developed. %The optimum amount of cells for this specific drone was found to be a total of 28 cells. A SEPIC converter will extract solar energy from a PV-module in order to charge the battery of the drone. The converter will be controlled by the micro-controller subgroup using MPPT (Maximum Power Point Tracker) algorithm and this will be done by supplying a PWM signal to the converter. Since the drone was not specifically designed for the project (thus not optimised when it comes to lift capacity and room for cell placement), the efficiency of the solar cells was not sufficient to extend the fight time by 25% (15.1% in summer, 5.6 in winter). Since these bottlenecks can easily be eliminated by replacing the drone and the cells, these results serve as a proof of concept and are an excellent starting point for future research. ... Read more

The Wireless Power Transfer (WPT) has been introduced decades ago for low power applications, and more recently, it has been used for industrial high power applications. WPT is gaining popularity because it presents several advantages over the power transfer through cable, such as the galvanic insulation between the power source and the load, the possibility of on-road charging for private electric vehicles, and it obviates the need of bringing around bulky cables of portable devices, especially the ones not standardized yet.

The subject of this thesis is an e-bike WPT charging system, using electromagnetic power transfer with resonant coupling. The WPT works through two coupled ferromagnetic coils with compensation capacitors. In particular, this thesis focuses on the control of the inverter of the e-bike WPT charging system.
Initially, some background on the WPT is given. Then, the problem treated in this project is defined, explaining the whole e-bike WPT charging system with its goals and constraints. The inductive and the resonant coupling are explained, including the possible compensation networks. Moreover, two different definitions of the bifurcation phenomenon are analyzed and compared. After this, power electronics topologies for both the primary and the secondary converters are presented, and the most suitable ones are chosen. Two possible operations for the inverter are discussed: the fixed frequency and the auto-resonant frequency operation. Additionally, a survey on the existing communication standards for WPT is presented, focusing in detail on the Qi specification from the Wireless Power Consortium.
The main contribution of this thesis is then explained in detail, which is the design of the control loop for the inverter, such that it works at auto-resonant frequency by automatically changing the operating point to achieve ZCS. The e-bike WPT charging system working at auto-resonant frequency gives a higher efficiency than when it is working at fixed frequency. Another crucial part of this thesis is also the validation of the theoretical model with measurements on a laboratory set-up. Finally, the main conclusions on the inverter control for the e-bike WPT charging system are given, together with recommendations for future research on the topic.
... Read more

This thesis is about the simulation of the permanent magnet motors of the Nuna Solar Car in order to find their fundamental motor parameters. These parameters can then be used in a Field-Oriented control algorithm to be used in a new motorcontroller for the team. A finite element analysis is done on the two current motors of the Nuna solar car, a radial flux Mitsuba motor and an axial flux Marand motor, with the intend to
find the fundamental motor parameters, the phase resistance, the inductance and the motor constant.
The model is presented and the simulation results are discussed. Also some variations to the current design have been made to test the adaptability of the simulation. Also some work is done to simulate the
entire drive system of the car. ... Read more

In this thesis the implementation of Field Oriented Control in the car of the NUON Solar Team will be discussed. The team decided to do research into the possibilities of a custom motor controller, and this thesis covers the beginning of that process. First a comparison between different control methods is made, and sensorless FOC is decided as the method to be used. Then the implementation of FOC is discussed. The Texas Instruments InstaSPIN™ technology has the preference for this implementation. This because it has all the elements of the control embedded in one microcontroller, along with a software estimator which eliminates the use of expensive sensors like a shaft encoder. Also the ease of use and the familiarity of TU Delft staff with this technology played a big part in this decision. With this technology, a simulation set-up was made as a proof of concept, which can also be used to teach the NUON Solar Team members the basics of motor control. After that the connections from the controller to the inverter are discussed, so it can be connected to other inverters in the future. In the controller, a CAN-interface is also implemented, which is essential for using it in the Nuna car. With the information presented in this thesis, the NUON Solar Team can continue the development of a controller. It is recommended to eventually leave the development kits used during this project, and integrate the MCU directly into an inverter. This will allow for well-tuned, efficient control of the motor with a small
footprint. ... Read more

Recent innovations in Electric Vehicles (EVs) will potentially change the future of the transportation industry. They will diversify the energy mix and reduce the dependence on fossil fuels. However, use of EVs only shifts the source of CO2 production to electricity generation plants. A smart solution to overcome this problem is the use of localized generated power and solar-powered charging stations are the best way to achieve it.

A solar powered e-bike charging station, installed on the TU Delft campus is one such example. The charging station is equipped with a meteorological station, sensors for monitoring performance, inverters and batteries. The PV system installed at the e-bike station was thoroughly modeled, considering both the location and meteorological conditions of the final installation [1]. To maximize the station’s utility, it is important to accurately predict the energy yield of the system. The modeling step comprises of several sub-models (irradiance, thermal and electrical model) which indicate the energy yield of the station as well as the power exchange with the grid. Though these models were based on (realistic) assumptions, there is a need to verify the assumptions against measured values.

In this thesis, the accuracy of existing irradiance, thermal and electrical models was evaluated by predicting the energy yield of the e-bike charging station. Further, the performance of these models, especially those related to the irradiance on the plane of the array and the instantaneous temperature of the PV modules, was improved. Also, two new decomposition models are introduced to improve the accuracy of obtaining diffuse irradiance from global horizontal irradiance specifically for the Netherlands. It was found that for accurate energy yield prediction it is necessary to optimize the models using
location specific parameters like sky view factor, albedo, INOCT etc. The energy yield predicted, using the improved models in this thesis, was only 17 kWℎ less than the measured yield for the duration Oct’16-Apr’17. ... Read more

This document is the bachelor graduation thesis of BAP Group B2. Together with BAP Group
B1 the objective of this project was to create a control network and DC/DC converter implementation
capable of fast, analog power management with active, remote-control and -interfacing of
multiple converter’s energy flows. The system will be designed to function in the solar-powered
eBike charging station on the TU Delft campus.
This document specifically is concerned with the design, simulation and testing of the DC/DC
converter. The thesis presents a bi-directional flyback DC/DC converter design and prototype
with analog power management, universal control signals and high integration potential.
These aspects are accomplished by building upon the traditional flyback DC/DC converter design
with respect to circuit topology, power-flow control, connectivity and accessibility. The
difficult regulation and measurement of DC power flow has been reduced to a set of analog
signals interpretable by any microcontroller, easing the integration of the converter into larger
energy and control networks.
A working prototype is presented and the inner-workings of the electrical circuit are discussed
and evaluated in detail. The converter is tested beyond the limit of the design requirements and
the performance is documented. Provided are possible reasons for malfunctioning and guidelines
for future improvements.
Design ... Read more

In this paper, the possibilities of a network of DC/DC flyback converters are explored. The implementation is as follows:
Multiple microcontroller units are connected to a single board computer (ODROID C1+) via the I2C bus. Data collected by the MCU's is logged to an external server, where it is accessable via the internet. Users are able to control the voltages and currents via a website. ... Read more