2019 Volume 27 Issue 1 Pages 25-30
This study presents instantaneous inductance estimation and a sensorless stroke estimation method of a linear resonant actuator (LRA). In LRA, the stroke information is most important since the maximum distance of the mover is not mechanically constrained. In order to estimate the stroke from the voltage equation, motor parameters such as effective resistance, effective inductance and force constant are required. Especially, the inductance of LRA may change due to magnetic saturation. Therefore, it is necessary to estimate the inductance during operation and update its value continuously. This paper proposes a method to estimate the inductance during operation by using the current slope in the pulse width modulation (PWM). Furthermore, a method for estimating the stroke using estimated inductance is proposed. The effectiveness of the proposed method is validated by the results of numerical simulation.
