Resonant Current Estimation and Phase-Locked Loop Feedback Design for Piezoelectric Transformer-Based Power Supplies

Comparison of BSPT and PZT Piezoelectric Ceramic Transformers for High‐Temperature Power Supplies

“…The power electronic converter was operated with an 80 V DC input and a dedicated ZVS controller, based on the frequency doubler phased‐locked loop control system described in ref. [22], which ensures the converter is operated at the correct frequency. By automatically adjusting the frequency, this controller ensures that the switch turns off at the zero‐crossing of thereby allowing the greatest opportunity for to charge the voltage on capacitor from 0 to 80 V before switch turns on after radians.…”

“…While several topologies of PT‐based resonant converter have been studied, the choice of topology is typically related to a specific application and will have minimal impact on the performance comparison between PTs. Therefore, we relate our work only to the popular inductorless half‐bridge inverter topology, [ 22 ] as shown in Figure 2.…”

Performance of PZT-based piezoelectric transformers for use in high-temperature converters

“…During testing, the converter was operated with an 80V DC input, with the half-bridge switches driven in antiphase with a 25% duty cycle. A dedicated ZVS controller based on the frequency doubler phased-locked loop control system described in [14] ensures the converter is operated at resonance by forcing the resonant current to be 𝜋/2 out of phase with the input voltage by controlling the operating frequency.…”

“…If the PT is designed to the criterion presented by Foster et al [9], zero-voltage switching (ZVS) can be achieved in this circuit, irrespective of load. A full description of the modes of operation during ZVS for this converter can be found in [9], [14].…”

Resonant current estimation and voltage regulation for piezoelectric transformer-based power supply

“…Since the resonant current is internal to a PT and cannot be measured directly, the resonant current should be estimated in order to generate a feedback signal. Traditional current estimation methods reported in the literature show good effective sign detection for the resonant current, these methods use either anti-parallel diodes or a voltage differentiator [5] [6]. However, they exhibit one or more of the drawbacks: 1) primary estimator implementation could increase total effective capacitance presented at PT input section, making ZVS even more difficult to achieve, 2) the estimated current is sensitive to system noise and could be affected by MOSFET switching events.…”