Common DC-Link Multilevel Converters: Topologies, Control and Industrial Applications

Multilevel converters (MLCs) are widely recognized for their exceptional benefits and have emerged as the preferred choice for medium- and high-power/voltage applications. Their usage has also been extended to low-power applications to overcome issues associated with high switching frequencies and electromagnetic interference (EMI) commonly...

A Variable-Frequency ZVS Modulation for Four-Switch Buck+Boost Converters with Seamless Step-up/down Mode Transition

This paper introduces variable-frequency zero voltage switching (ZVS) modulation strategy for the four-switch buck+boost converter with one operating pattern for the inductor current, i.e., three-segment inductor current modulation control. The proposed modulation scheme guarantees a smooth transition from step-up to step-down or from step-down...

Over-the-Air Characterization Techniques for Antenna-Coupled Direct-Detectors at Terahertz Frequencies

The continuous advancements in the coverage and sensitivity of terahertz direct-detector imagers places increasing constraints on the test benches needed for characterization. Already, relative differences on the order of a few decibels are observed between simulated and measured performance in the state-of-the-art literature. This...

Ultrasound for Data Transfers from Deep Implants: an Experimental Comparison Between Binary-Frequency-Shift-Keying and On-Off-Keying with Backscatter Modulation

Implantable devices need to communicate information to the outside world. For deep-seated miniaturized implants ultrasound communication can be favourable. However, implants need to operate during movement, and the selected communication scheme should be assessed accordingly. In this work, we implemented a simple protocol to transfer data...

Three-Mode Variable-Frequency ZVS Modulation for Four-Switch Buck+Boost Converters With Ultra-high Efficiency

This article introduces a three-mode variable-frequency zero-voltage switching (ZVS) modulation method for the four-switch buck+boost converter. This method makes this circuit concept well suited for applications, such as wireless power charging of electric vehicles, where this circuit operates as a power buffer between the resonant converter...

A Dual Active Bridge Converter with an Extended High-Efficiency Range by DC Blocking Capacitor Voltage Control

A Dual Active Bridge (DAB) converter can achieve a wide high-efficiency range when its input and output voltages are equal, assuming a 1:1 turns ratio for its isolation transformer. If its input or output voltage is doubled, efficiency of the DAB will drop significantly, because of the introduction of hard switching and high circulating power....

Wireless communication systems using signal space diversity

The next generation communication devices are foreseen to not only support a large variety of applications, ranging from speech, audio and video graphics but also be able to maintain connection with many other devices (rather than a single base station) in different changing environments. The aim of the dissertation is to analyze digital...

Hiding correlation-based Watermark templates using secret modulation

A possible solution to the difficult problem of geometrical distortion of watermarked images in a blind watermarking scenario is to use a template grid in the autocorrelation function. However, the important drawback of this method is that the watermark itself can be estimated and subtracted, or the peaks in the Fourier magnitude spectrum can be...