Research and Development of Short-Range Wireless Power Transmission System

Recently, there has been much interest into the area of Magnetic-coupled resonator wireless power transmission (WPT) systems. WPT is an efficient way for the transmission of electric power from one point to another through vacuum or atmosphere without the use of wire or any substance. By using this technology, it is possible to supply power to places, which is hard to do using conventional wires. Several applications of wireless power transfer are apparent and obvious. Firstly, WPT could eliminate traditional charging systems in place today. Instead of plugging in a mobile phone or laptop via power cord to charge the battery, wireless power can be harnessed and implemented in a home such that a laptop and phone charge continuously and wirelessly without the need for plugging anything in. Higher level applications include charging of electric vehicles (EVs). Driving EVs is become more and more prevalent on the roads. The feasibility of driving such a vehicle can be charged wirelessly and automatically via WPT systems. This project designs and development a WPT systems which include two important components: rectifier and LDO. In WPT receiver the input AC sources have to be converted into DC sources to power up downstream electronics. The full-wave active rectifier is commonly used to convert AC power into DC power. To achieve a high power conversion efficiency (PCE) full-wave active rectifier using dynamic delay compensation circuits. The dynamic delay compensation circuits could dynamic adjusting the offset of the comparator, and reduce the reverse current of the active rectifier. The proposed active rectifier provides a lower power consumption, and higher power and voltage conversion efficiency (PCE, VCE). The PCE of proposed active rectifier in this project reached over 95%, and the output power reached 1.5 W. The active rectifier is designed in 0.18μm CMOS device technology, the input resonant frequency is 13.56 MHz, and peak voltage is 3.6V. After the rectifier generates the output voltage, the simplest way to regulate the output voltage of the rectifier is to add a low dropout linear regulator. Linear regulators can filter out the input supply noise and provide a clean supply voltage to drive noise sensitive sensor circuits, wireless communication front-end circuits, critical paths in VLSI chips, and simply provide a voltage step-down function in low-cost applications. To realize a current-efficient LDO regulator, a proposed technique permits the linear regulator to transform itself between 2-stage and 3-stage cascaded topologies with respective power transistor, depending on the load current condition. It offers an ultra-low quiescent current (1 uA) solution at no load whilst achieving high load regulation across the whole load current range. Beside this, we also introduce an LHP zero to improve the phase margin of the linear regulator. The linear regulator is designed in 0.18μm CMOS device technology, with input voltage range of 1.5 V ~ 3 V, while regulating the output range of 0.9 V ~ 1.8 V.

Project ID:PB10708-2383
External Project ID:MOST107-2221-E182-061