This thesis applies structural reliability measures for the performance based design of residential PV system structures. These measures are intended to support designers in delivering systems with quantified and consistent reliability. Existing codified practices prescribe global factors (allowable stress design) and partial factors (load and resistance factor design) intended to provide an acceptable level of reliability as defined by historical practice. When applied to residential PV systems this prescriptive approach has two flaws, (1) calibration efforts needed to ensure consistency across structural system types have not kept up with the commercially available system types and (2) the actual expected reliability is not quantified and available to support decisions. The proposed reliability measures include probability of failure conditioned to wind speed in a fragility curve and the reliability index β, both of which are commonly used in performance based design. The approach is demonstrated through the application of the reliability measures to code compliant designs. Diverse system types are utilized to demonstrate how the existing code prescribed approach may lead to non-uniform structural performance. For each of the system types on which the reliability measures are demonstrated, a code compliant design is developed for three roof slopes, wind tunnel testing is conducted to provide an experimental measure of wind pressure coefficients, system specific fragility curves are generated to quantify the probability of failure conditioned to a set of wind speeds, and then, a site specific wind model is applied to produce a probability of failure and reliability index β. Through the performance based approach proposed in this thesis, two key outputs show non-uniform and unanticipated structural performance of PV systems designed according to the prescriptive code method. The two key outputs which illustrate this finding are fragility curves which illustrate the probability of failure over a range of wind speeds and reliability index, β values which couple the structural and wind distributions for a single measure of reliability.

This Master of Applied Science thesis presents a single phase grid connected DC/AC inverter with reactive power (VAR) control for residential photovoltaic (PV) applications. The inverter, utilizing the voltage sourced inverter (VSI) configuration, allows the local residential PV generation to actively supply reactive power to the utility grid. A low complexity grid synchronization method was introduced to generate the parallel and orthogonal components of the grid voltage in a highly computationally efficient manner in order to create a synchronized current reference to the current control loop. In addition, the inverter is able to use a small long life film type capacitor on the DC-link by utilizing a notch filter on the voltage control loop. Simulations were performed on PSCAD/EMTDC platform and a prototype was also developed in the lab to prove the effectiveness of the controllers and the grid synchronization method.

This Master of Applied Science thesis presents a single phase grid connected DC/AC inverter with reactive power (VAR) control for residential photovoltaic (PV) applications. The inverter, utilizing the voltage sourced inverter (VSI) configuration, allows the local residential PV generation to actively supply reactive power to the utility grid. A low complexity grid synchronization method was introduced to generate the parallel and orthogonal components of the grid voltage in a highly computationally efficient manner in order to create a synchronized current reference to the current control loop. In addition, the inverter is able to use a small long life film type capacitor on the DC-link by utilizing a notch filter on the voltage control loop. Simulations were performed on PSCAD/EMTDC platform and a prototype was also developed in the lab to prove the effectiveness of the controllers and the grid synchronization method.

This thesis investigates the economic viability of a grid connected PV system integrated with battery storage in a multifamily home in Sweden. In addition, a fleet of electric cars is added to the system and its economic feasibility is analyzed. The analysis is further classified based on the roof area available for PV installation, wherein system 1 considers nearly the entire roof area of 908 m2 and system 2 is assumed to have less than half the roof area of 360 m2 for PV installation. To help with the assessment, five scenarios are created; where scenario one represents a baseline Swedish cooperative without PV, scenario two includes a PV system; scenario three incorporates battery storage; four considers an electric vehicle fleet embedded into the system and scenario five has a fleet of gasoline cars. These scenarios are applied to the two systems and their results compared. To address the question of this thesis both scenarios 2 and 3 are simulated in System Advisor Model (SAM) and scenario 4 is modeled in Matlab. The outputs are exported to Excel in order to obtain the Net Present Value (NPV), which is the economic indicator for this assessment. In none of the tested scenarios the NPVs’ are positive and the best result is observed in a PV system installed with battery storage in a roof area of 360 m2, which has a NPV of -82,000 SEK. A sensitivity analysis is done to assess the changes in NPV by varying the input parameters. It is concluded that battery storage is not yet economically viable in a Swedish multifamily house.