The goal of this bachelor's end project is to reduce the fluctuation of power in a dynamic inductive power transfer system (DIPT) by controlling the input power using a control system. When a receiver coil in a dynamic wireless charging system moves over transmit coils, the delivered output power to its load fluctuates. Three different control system architectures are proposed, analysed, and simulated. These are feedforward control, feedback PI control and a receiver-side cascaded boost converter with PI control. Also other methods in the literature are analysed and briefly discussed.

First, a method for simulating a DIPT system in Simulink, with a realistic time-varying mutual inductance profile, is developed and verified with a prototype. This method is later used to verify the proposed control systems.

With feedforward control the power fluctuations are reduced by compensating for the changing mutual inductance at the receiving side. An accurate model of the varying mutual inductance is required. The system succeeded in reducing the power ripple in a controlled setting, but it will be hard to implement in practice.

Direct feedback control using a PI controller does not require an accurate model of the system and also achieves significant power ripple reduction. It does, however, require a feedback signal from the receiver side, making it more complex to implement.

The receiver side boost converter reduces the power ripple by controlling the power at the receiver side. When implemented with PI control, this does not need a model or communication with the transmitting side. A disadvantage of this system is that extra hardware is required, at the cost of extra components, cost and weight.

Wireless power transfer has been around for a long time. In 1899 Nikola Tesla demonstrated that it was possible to transfer power using a pair of coils. This technology has advanced to now charge a wide range of portable devices, such as phones. In this thesis, a wireless charging system is designed to be integrated into a power bank with UV-C sterilization to charge phones.

The design focuses on creating a small and highly efficient module to transfer energy from the power bank battery to the phone with as little losses as possible. The design adheres to the Qi standard from the Wireless Power Consortium by following the MP-A2 reference design. The design consists of a voltage regulator to provide a constant voltage, a controlled inverter that manages output power, and a series compensated transmitter coil. LTspice simulations predict the power efficiency to be 74% from the battery to the receiver. A prototype PCB was designed and assembled to demonstrate the performance of the design in practice and transferred 5W at an efficiency of 67%. This shows potential for future integration of the design into the power bank.