Inductive wireless power transmission for automotive applications

Rozman, Matjaz (2019) Inductive wireless power transmission for automotive applications. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Technology has revolutionised all aspects of human life at all consecutive intervals and Fourth Industrial Revolution is no different. Daily transport and energy industries not only shape the future of a country’s economy, but also make the economy highly yielding due to recent advances. Electric vehicles (EV) have been rapidly invading the market share during recent years. The advancements in EV and enhanced market share demand EV charging, being more reliant on either conventional plug-in charging or wireless charging. Given the limitations within battery related apparatus such as escalating battery costs, higher weight and lower power density, wireless power transfer (WPT) is a novel state of the art technology in energising. WPT has remarkable characteristics such as enhanced flexibility, mobility, convenience and safety, indicating potential benefits, if it is adopted for EV with similar efficiency; for example, it can eliminate the use of charging cables. Despite the fact that the wireless charges for EV, have undergone significant development phase during the last decade, many design limitations are yet to be addressed. Although the technology has been commercially outgrown, key limitations such as limited efficiency over distance, limited driving range, vulnerability to misalignments, or positional offsets are yet to be researched. Moreover, although high system efficiency can be attained, the distance variations between the transmitter and receiver and the misalignments will impact the system efficiency. This thesis addresses the aforementioned limitations and design challenges of the magnetic resonance WPT system, and proposes a novel transmitter and receiver circuit and coil designs, to minimise the impact of distance variations and coil misplacement, reduce the size and improve charging performance. This thesis focusses on inductive wireless power transfer (IWPT) which is also referred to as magnetic resonance and reviews and contrasts other WPT mechanisms. Additionally, it presents a detailed mathematical analysis of inductive wireless power circuit model to obtain accurate modelling parameters. Two and four loop strongly coupled magnetic resonance (SCMR) wireless power systems have been mathematically analysed and their performance has been evaluated. A novel combined, conformal strongly coupled magnetic resonance system (CSCMR) has been combined with SCMR, in order to minimise the dimensions of the receiver and compensate the coupling factor due to distance variations between the transmitter and receiver. In the second phase, additional inductors were added to the existing loosely coupled system to obtain higher efficiencies over higher distances. The size of the system has significantly reduced due to the additional smaller transmitter and receiver inductor which were added to the existing system to achieve better performance. The validity of each design has been discussed via a set of simulations, and their measurements have been obtained via prototypes. Finally, a smart WPT charging system, consisting of six transmitter loops and a sensor network array, for an autonomous parking space was developed. The proposed method reduces the energy required for determining a car’s location, eventually increasing the performance of the charger.