New DC-DC Converter Enhances Piezoelectric Power Generation

French researchers have made a groundbreaking discovery that could revolutionize the way we use piezoelectric converters in various electronic devices such as TVs, phones, tablets, and electrical tools.

The team at CEA-Leti in France has successfully developed a DC-DC converter that effectively reduces the piezoelectric voltage swing and circulating current. This innovative converter is designed based on two piezoelectric resonators (PR) in an isolated dual bridge configuration.

Through experimental validation, the researchers have demonstrated a remarkable improvement in efficiency, with gains of up to 11% and an average increase of 5% in using mechanical motion to generate power. In a conversion scenario from 200 V to 120 V, the converter achieved an impressive efficiency of 96.2% with an inductive assisting circuit, 94.3% with a piezoelectric assisting circuit, and 87.4% without any assisting circuit. While the piezoelectric resonator offers enhanced efficiency within a smaller operating range compared to inductance, it results in a flatter converter.

During the Leti Innovation Days event, researcher Ghislain Despesse highlighted the versatility of piezoelectricity in power conversion, emphasizing its operation at high frequencies exceeding 100kHz without limitations on input power. This capability enables the generation of power levels reaching several hundred watts, expanding the potential applications across a wide spectrum of devices with most converters rated below 100W.

One of the challenges associated with piezoelectric converters is the presence of parallel capacitance in the resonator's equivalent circuit, necessitating charging and discharging processes that lead to circulating currents and associated losses. The newly developed DC-DC converter eliminates the need for transformers, paving the way for broader utilization of piezoelectric converters in diverse applications.

The dual-bridge isolated piezoelectric resonator converter (DB-IPRC) introduces a novel approach to achieving isolation through two independent piezoelectric resonators. This enhanced version of the DC-DC converter significantly enhances efficiency while upholding the fundamental principle of converter isolation.

Despesse envisions a future where the adoption of piezoelectric resonators instead of inductors in power conversion systems will result in a substantial reduction in the size of power converters. This breakthrough opens up possibilities for compact conversion solutions in isolated converters, making them compatible with a broader array of applications ranging from consumer electronics like TVs, phones, and tablets to various electrical tools.

For more information, visit www.leti-cea.com