Implementation of Control Strategy for Step-down DC-DC Converter Based on Piezoelectric Resonator

Abstract

With the growth in demand for miniaturization in power electronics, the current solutions are starting to display their limits in dimensions, power densities and efficiency. To meet the previous demands, the new piezoelectric materials achieving high power densities and efficiency could be the solution to ensuring the requirements. The piezoelectric resonators (PRs) and the piezoelectric transformers (PTs) have been used previously. Unlike the PTs, the use of PRs in power electronics has not been fully explored, and their use has been limited to operating as switched capacitors. However, a new operating principle using PRs based on energy and electrical balance exhibits good performances in steady state. In this paper, our motivation is to investigate in the capability to control a dc-dc converter based on PRs using this operating principle. Indeed, this paper presents the control strategy of a new step-down DC-DC converter based on a piezoelectric resonator (PR), which is used as an energy storage element. The operating principle of the converter is also presented. Moreover, the control algorithm has been implemented in field programmable gate array (FPGA) to regulate the output voltage. The control principle is validated experimentally for input-output voltages 120-48 V, and achieving an efficiency up to 94% for large operating power range.

A New Topology of DC–DC Converter Based on Piezoelectric Resonator

“…By adjusting t2 while keeping the other switches in the ZVS operation mode and synchronized on the mechanical oscillation, one can change the energy balance and then makes I increases or decreases to adjust the output current and then to regulate the output voltage. Yet, we have demonstrated and experimentally validated the control strategy of this converter in [26]. At the same output power, the efficiency decreases while reducing the output voltage, because the current amplitude I and the losses (2) increases while Iout=Pout/Vout increases, see (23).…”

“…The timing and frequency are then tuned to ensure ZVS and load conditions by using the observed waveform of VP. Nevertheless, we have implemented the optimal law control of the presented dc-dc converter based on PR in [26], that includes the synchronization with internal current i, load regulation and ZVS regulation.…”

“…As shown, the operating frequency decreases by increasing the power. Thus, for closed-loop operation, the operating frequency of PR should be measured, and the control of the switches must be synchronized with i like in [22]- [26].…”