Tuned driving of piezoelectric resonators: Impedance matching

For optimal operation of piezoelectric resonators, the electrical impedance of electronic drivers and the resonator itself must be matched. Lack of matching results in a non smooth transmission of electrical power between the drive and the load which, in turn, leads to heating and poor efficiency. The rest of properties of the driving voltage (frequency, amplitude and phase) are also affected by this mismatch. This paper presents the optimal design of power drivers for piezoelectric resonators. This approach is based on a first stage of electro-mechanical experimental characterization. This first step sets the basis for an impedance matching process. The approach has been experimentally validated on a well known piezoelectric resonator: the ultrasonic motor.