Phase Estimation for Phase-Locked-Loop Ultrasonic Drive

• Main Authors: Ting-wei Kuo, 郭定緯
• Other Authors: Shiang-Hwua Yu
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/x7836k

碩士 === 國立中山大學 === 電機工程學系研究所 === 106 === An ultrasonic drive requires frequency locking at its resonance for high vibration efficiency. Phase locked loop is a common approach to achieving this purpose. To fully employ the power of phase locked loop, however, it requires the precise phase information, which is difficult to obtain for coarsely sampled signals. This thesis combines the signal reconstruction method and Newton’s method to reconstruct the zero-crossing points of coarsely sampled waveforms and thereby to precisely estimate the phase difference of the driving voltage and current. The algorithm is implemented on an FPGA with the ultrasonic driving circuit. With the proposed phase estimation algorithm, the performance of the phase-locked-loop ultrasonic drive is improved over the conventional bang-bang design.