Basic Transducer Interfacing Concepts

Before developing reasonable interfacing and power conditioning concepts, the nature of electromagnetic vibration transducers needs to be explored. Therefore, this Chapter starts with introducing general terms of transducer interface operation and the power processing chain in Sect. 2.1. There, also a further overview of a power processing and conditioning chain is given and basic evaluation metrics are defined. Thereafter, the electromagnetic vibration transducer is studied in Sect. 2.2. Application of continuous power extraction versus averaged (buffered) power extraction is compared and optimal load ratios for fractional-voltage tracking are found. These findings are the basis for developing a MPPT approach in Sect. 2.3. The focus of the developed MPPT scheme is a trade-off between a high power extraction efficiency and low operational losses in the interface. In addition, basic rules for finding system parameter values for a given transducer specification complete this part. Then, Sect. 2.4 presents architectures, topologies, and related implementation constraints for realizing the key components of the energy-harvesting based supply layer, i.e. the rectifier, the MPPT interface, and the voltage regulation. A final summary in Sect. 2.5 concludes the main findings necessary for the transistor-level circuit development given in the following chapters.