Adaptive AC-DC Converters for Wireless Power Transmission

• Main Authors: Ye-Sing Luo, 羅業興
• Other Authors: 劉深淵
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/rj6w2w

博士 === 國立臺灣大學 === 電子工程學研究所 === 105 === For the development of the Internet of Things (IoT), wearable devices, and implantable medical devices, the wireless power transmission is receiving significant attention. In these applications, the external power from a transmitter is transmitted by the coils / antennas, and an AC voltage will be received in a wireless device. To convert the AC voltage into a DC one for the device working, an AC-DC converter is widely adopted. The cores of the AC-DC converters usually use a diode-connected MOS transistor or a comparator-based active diode. However, the diode-connected MOS transistor and the active diode suffer from the threshold voltage of a transistor and the turn on/off delay time of the comparator, respectively. Both of them reduce the output voltage and the power conversion efficiency (PCE) of the AC-DC converters. Hence, increasing the output voltage and the PCE are the crucial topics for the AC-DC converters. This thesis presents two AC-DC converters to increase their output voltages and PCEs. In chapter 2, an AC-DC converter with adaptive threshold voltage compensation is presented. A compensation voltage is adjusted in the background to compensate the threshold voltage of the transistors. The output voltage and the PCE of the AC-DC converter are increased. In chapter 3, an AC-DC converter using an adaptive pulse controller is presented to receive the low input amplitude. The adaptive pulse controller adjusts the delay time and pulse-width of the pulses in the background to turn on/off the power switches. The output voltage is kept as high as possible, and the PCE of this AC-DC converter is enhanced. Finally, the conclusions are given in chapter 4.