Intermittent nature of renewable energy sources like the wind and solar energy poses new challenges to harness and supply uninterrupted power for consumer usage. Though, converting energy from these sources to useful forms of energy like electricity seems to be promising, still, significant innovations are needed in design and construction of wind turbines and PV arrays with BS systems. The main focus of this research project is mathematical modelling and control of wind turbines, solar photovoltaic (PV) arrays and battery storage (BS) systems. After careful literature review on renewable energy systems, new developments and existing modelling and controlling methods have been analysed. Wind turbine (WT) generator speed control, turbine blade pitch angle control (pitching), harnessing maximum power from the wind turbines have been investigated and presented in detail. Mathematical modelling of PV arrays and how to extract maximum power from PV systems have been analysed in detail. Application of model predictive control (MPC) to regulate the output power of the wind turbine and generator speed control with variable wind speeds have been proposed by formulating a linear model from a nonlinear mathematical model of a WT. Battery chemistry and nonlinear behaviour of battery parameters have been analysed to present a new equivalent electrical circuit model. Converting the captured solar energy into useful forms, and storing it for future use when the Sun itself is obscured is implemented by using battery storage systems presenting a new simulation model. Temperature effect on battery cells and dynamic battery pack modelling have been described with an accurate state of charge estimation method. The concise description on power converters is also addressed with special reference to state-space models. Bi-directional AC/DC converter, which could work in either rectifier or inverter modes is described with a cost effective proportional integral derivative (PID/State-feedback) controller.

In the eastern part of Stockholm, a major urban development project is taking place. It is called Stockholm Royal Seaport and up to the year 2030 approximately 12000 new homes, 35000 workplaces and 600000 square meters of commercial areas will be added to the area. The project has been given a very ambitious environmental action program. As a part of that, the City of Stockholm has established a logistics centre in the area. The logistics centre is supposed to coordinate all transports of building material and handle the waste during the construction phase. One objective with the logistics centre is to reduce the number of transports and thereby reduction in the use of energy. The thesis-work mainly focused on developing an optimisation program for electricity supply to the logistics centre, in order to find the optimal way of managing charging and the use of electrical energy, when the logistics centre has procured a new batterypowered truck. The main objective is to minimize the purchase of power bought from the grid, for the loads at the logistics centre at Stockholm Royal Seaport. This thesis not only focused on this site in particular, but the work also resulted in creating a benchmark model that could be used for studying the electrification process for other construction sites in general. The logistics centre contains stationary battery storage, electrified distribution trucks, a PV generation system, and other electrical loads at the site. This thesis aimed at considering all the limitations and constraints for all the resources at the site and then finding an optimal method of utilising these resources in order to minimize the overall energy consumption. In this thesis, the optimal sizing of the battery for an electrified distribution truck is also performed considering the overall functional requirements of the distribution truck. Various charging strategies have been identified and simulated to understand the routines of charging the truck and their direct impact on the grid due to the purchase of energy during various hours of the day. The work resulted in optimised use of assets at the site during different hours of the day. The simulation work identified the best strategy and the use of resources at the site thus saving some amount of energy consumption at the site. This directly resulted in saving overall operational costs of the logistics centre. / I den östra delen av Stockholm pågår ett stort stadsutvecklingsprojekt. Det kallas Norra Djurgårdsstaden och fram till år 2030 kommer cirka 12000 nya bostäder, 35000 arbetsplatser och 600000 kvadratmeter kommersiella områden att läggas till området. Projektet har fått ett mycket ambitiöst miljöprogram och som en del av det har Stockholm stad inrättat ett logistikcenter i området. Logistikcentret ska samordna alla transporter av byggmaterial och hantera avfallet under byggfasen. Ett mål med logistikcentret är att minska antalet transporter och därmed minska energianvändningen. Examensarbetet fokuserade främst på att utveckla ett optimeringsprogram för elförsörjningen till bygglogistikcentret för att hitta det optimala sättet att hantera laddning och användning av elektrisk energi när logistikcentret investerar i en ny batteridriven lastbil. Huvudmålet är att minimera importen av elkraft som köps från nätet för att försörjar lasterna vid Norra Djurgårdsstadens Bygglogistikcenter. Målet är att göra en vägledande modell som kan användas för att studera elektrifieringsprocessen för byggarbetsplatser i allmänhet. Detta logistikcenter innehåller stationär batterilagring, elektrifierade distributionsbilar, ett PV -genereringssystem och andra elektriska laster på platsen. Syftet med denna avhandling var att överväga begränsningarna och resurserna på platsen och sedan hitta en optimal metod för att använda dessa resurser för att minimera den totala energiförbrukningen. I detta examensarbetet utförs också den optimala dimensioneringen av batteriet för en elektrifierad distributionsbil med beaktande av de övergripande funktionella kraven för distributionsbilen. Olika laddningsstrategier har identifierats och simulerats för att förstå rutinerna för laddning av lastbilen och dess direkta påverkan på nätet på grund av inköp av energi under olika timmar på dygnet. Arbetet resulterade i optimerad användning av tillgångar på platsen under olika timmar på dygnet. Simuleringsarbetet identifierade den bästa strategin och användningen av resurser på platsen, vilket sparar en viss energiförbrukning på platsen. Detta resulterade direkt i att spara logistikcentralens totala driftskostnader.