Ultra-High-Bandwidth Power Amplifiers: A Technology Overview and Future Prospects

Abstract

Testing of power electronic converters can advantageously be carried out in power-hardwarein-the-loop (P-HIL) environments that emulate the behavior of power grids, electric motors, etc. The interface between the model and the device under test requires a power amplifier whose bandwidth ultimately limits the accuracy of the emulation. Hence, there is a need for general-purpose AC power amplifiers with ultra-high power bandwidth. This paper first provides a comprehensive review of amplifier concepts proposed over the past decades, i.e., linear power amplifiers, switch-mode amplifiers, including advanced variants such as multilevel (parallel-interleaving) and multicell (series-interleaving) topologies, as well as hybrid approaches that, e.g., combine analog and switch-mode stages. Based on this review, the two key concepts (parallelinterleaving of bridge-legs and cascading of converter cells) that facilitate high efficiency and ultra-high power bandwidth are identified and discussed, covering also suitable isolated mains interfaces and control considerations. Finally, we present a three-phase amplifier system that uses six cascaded converter cells per phase to realize an effective switching frequency of 3.6 MHz. The prototype thus achieves a measured power bandwidth of 100 kHz at the nominal phase output voltage of 230 V rms, and an output power of up to 10 kW per phase.INDEX TERMS Power-hardware-in-the-loop (P-HIL), grid emulation, motor emulation, power amplifier topologies, switch-mode power amplifier, ultra-high-bandwidth power amplifier.

A Physics-Informed Scaling Method for Power Electronic Converters in Power Hardware-in-the-Loop Test Beds

“…This is possible due to the high computational power of CPUs in realtime simulators. Adding to this, the power amplifiers' high bandwidth is wide enough to reflect all the time domain variations working as high fidelity controllable dc and ac sources [25]. Stand-alone PHIL mode-based emulation can be used to study the steady-state performance of the FSC with real controller validation, whereas, dynamic PHIL mode can be used to explore both the transient and steady-state behaviour of the FSC along with the real controller validation.…”

High-Bandwidth Isolated Voltage Measurements With Very High Common Mode Rejection Ratio for WBG Power Converters

“…(Corresponding Author: Pascal S. Niklaus) P. S. Niklaus, R. Bonetti, C. Stäger, J. W. Kolar and D. Bortis are with the Power Electronic Systems Laboratory, Swiss Federal Institute of Technology, Zurich 8092, Switzerland (e-mail: niklaus@lem.ee.ethz.ch; bonetti@lem.ee.ethz.ch; cstaeger@ethz.ch; kolar@lem.ee.ethz.ch; bortis@lem.ee.ethz.ch). CMRR @ 100MHz / dB [10] [8] [6] [12], [13] This Work [9] † ‡ [11] measurements have to be performed on floating reference potential, e.g., in multi-level/multi-cell converters [4], that is, the reference potential of the voltage to be measured differs from the reference potential of the measurement equipment (e.g., the oscilloscope), which is typically referred to Protective Earth (PE). Furthermore, isolation between different measurement channels is required when various measurements, all with different reference potential, are performed simultaneously.…”