Self-Powered Multifunctional Sensor of Positive Displacement Motor Based on Triboelectric Nanogenerator

In response to the testing requirements of downhole positive displacement motor (PDM), this research proposes a self-powered multifunctional sensor based on the triboelectric nanogenerator that can simultaneously measure the rotating speed, rotating angle and abrasion. Tests, including speed measurement tests, angle measurement tests, abrasion tests and reliability tests, were respectively tested after the sensor is manufactured. Speed tests results show that the measurement range is 0 to 900 r/min, the measurement error is less than 3%, and the maximum output voltage amplitude can reach 5.5 V. Angle tests results show that the minimum resolution is 60 degrees, and the measurement error is less than 5%. Abrasion tests results show that three abrasion thresholds of 0 mm, 0 to 20 mm and greater than 20 mm can be detected. Reliability tests results show that the sensor can work normally in an environment where the temperature is less than 250 degrees Celsius and the humidity is less than 90%. In addition, the power generation performance had also been tested, and the results show that the friction model and the sensing model of the sensor can output a maximum power of 28.3 \times 10.9\text{W} and 5.7 \times 10.9\text{W} respectively when connected in series with a 1000M \Omega load. Compared with the traditional downhole sensors, this research can working normally in self-powered model at higher temperatures, and has more measurement parameters.