A Sensorless Self-Tuning Resonance System for Piezoelectric Broadband Vibration Energy Harvesting. - Shi Ge 001; Yinshui Xia; Yanmei Yang; Junfu Chen; Yansheng Peng; Huakang Xia; Xiudeng Wang; Libo Qian (IEEE Trans. Ind. Electron., 2021)