Design and development of high efficiency wireless photovoltaic power transfer system

Wireless power transfer (WPT) is an electronic device that converts direct current (DC) power to be alternating current (AC) power on the transmitter coil using an inverter circuit and transmits it without wire to the receiver coil based on the concept of inductive coupling. Normally, the switching time of the inverter circuit is conducted by an analog timer and the switching components are bipolar transistor. It causes a desired frequency of the switching signal is difficult to be set for a suitable driver to drive the driving terminal of the switching components, also the voltage and current level of the switching components are low. An unsuitable value of inductance of transmitter and receiver coil can cause an unmatching frequency. These problems cause a low transmitted power, low efficiency and short transferring distance. Generally, battery is as main DC voltage source of WPT system, but it is not suitable to be applied in the moving area. It is due to that the battery needs to be charged during or after operating. The photovoltaic (PV) module issuitable to replace the battery for this condition. The performance PV module depends on solar irradiance and it is different in one area to the other area. Thus, a study of solar irradiance related to the PV module performance and the magnetic field intensity of the transmitter coil are important on the wireless photovoltaic power transfer (WPVPT) system. The objectives of this thesis are to designs, simulates and analyses a WPT system with digital microcontroller and power MOSFETs for improving its performance with a longer transferring distance. The other objective is to simulate and analyse solar irradiance related to the PV module performance and the magnetic field intensity of solenoid in the WPVPT system. The design of WPT system is conducted by calculating the inductance value and constructing the transmitter and receiver coil for the diameter of 16.6 cm and 47.5 cm with the frequency system of 2.5 kHz. The development of inverter circuit and rectifier circuit are also conducted for the transmitter and receiver sides of WPT system. An experimental and simulation of WPT system are conducted to validate its performance for a required DC voltage source and distance between the transmitter and receiver coil. The data of solar irradiance for the year of 2015 is analysed and related to the performance of PV module and magnetic field intensity generated by the transmitter coil. An experimental and simulation of WPVPT system are also conducted to validate its performance for the different condition of solar irradiance and PV module performance. The results show that the performances of WPT system are valid for the experimental and simulation results based on the error percentage. The DC power on the receiver side of WPT system will be decreased with a longer distance between the transmitter and receiver coil. The simulation result of magnetic field density on the transmitter coil shows that the magnetic field density is affected by the magnitude of AC current that flows through the transmitter coil for the constant turn number of transmitter coil and the constant coil length. The magnitude of AC current that flows through the transmitter coil depends on the level of DC voltage source or PV module voltage. The increasing of DC voltage source or PV module voltage causes the increasing of AC current and magnetic field density on the transmitter coil and increasing the capability of arriving magnetic field on the receiver coil. The experimental and simulation of WPVPT performance are also valid for the different condition of solar irradiance and PV module performance.