Application of hybrid-loop control approach to inverter design with piezoelectric transducers

A hybrid-loop control approach applied to inverter circuit design with piezoelectric transducers is proposed in this paper. This approach was motivated because the transducer is easily affected by the temperature effect and damping pressure, causing the mechanical frequency drift and unstable current variation. In view of these demerits, a hybrid-loop control mechanism is suggested to achieve both phase-tracking and constant-current control such that both operation frequency and vibration strength can be well controlled while maintaining a stable mechanical frequency. Moreover, by embedding this hybrid control concept into microprocessor controller units without adding any further sensors devices, the design cost is found to be meanwhile reduced. To validate the feasibility of this approach, the method has been validated through mathematical analysis and hardware realization. Test results confirm the performance improvement of the approach for piezoelectric transducer applications.