Investigation on the efficiency potentials of anti-resonat driven high power ultrasonic systems compared to resonant operation

• Applicants: Professor Dr.-Ing. Axel Mertens; Dr.-Ing. Jens Twiefel
• Subject Area: Mechanics ; Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 382779182

High power ultrasonic systems are well established in many industrial applications. Those, i.e. the ultrasonic welding, have the need for faster and more energy efficient systems. The main focus of this proposal is increasing the knowledge on ultrasonic systems including its power electronics with a special focus on transient and efficiency aspects. In the state of art is no objective comparative study on the different operation strategies available. Especially the operation of power ultrasonic systems at anti-resonance is not sufficiently investigated.The project proposal aims to close this gap. This will be carried out by the investigation of an ultrasonic system consisting of an ultrasonic transducer and a power electronics in resonant and anti-resonant operation.It will be studied if the utilization of novel semiconductors (here: GaN) can reduce the internal and system losses as well as the switching losses at high switching frequencies (about 1 MHz). One essential question is the potential of reducing the size of filter components though the high switching frequencies. This includes a detailed research on the additional losses within the filter components. To enable the developed power electronics for resonant and anti-resonant operation of the ultrasonic transducer, different voltage levels have to be provided. This will be realized by developing two suited HF-transformers. Those will be detailed investigated and designed with respect to their properties including leakage inductance, internal and coupling capacitance.Suited model based control algorithms will be investigated with respect to settling time, stability and efficiency. Here the operation mode in combination with different load levels will be detailed studied. Hence a load emulation system will be extended and utilized for the comparative study. This allow high load dynamics and very good reproducibility.One important question, is which is the optimal operation mode, resonant or anti-resonant operation. The literature is providing limited studies on piezoelectric elements only, they provide the hypothesis that anti-resonance has major advantages. Typical pre-stressed bolted transducer for high power ultrasonic applications have not been covered yet. Moreover, the separation and identification of losses as mechanical, coupling and dielectric losses is an important task in the project. This will be used for increasing the fundamental understanding and model validation.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Jörg Wallaschek