EA322 - Energy harvesting

In view of the growing number of low-power wireless sensors, recovering energy from the environment is proving to be a promising solution for meeting their energy needs, and doing away with the need for conventional batteries. 

Batteries are still widely used today, despite their considerable cost, limited lifespan and potential pollutant emissions. Energy harvesting is a promising alternative that is more respectful of the environment and enables theoretically infinite powering of wireless sensors in the environment. Solar, thermal and vibratory energy are currently being extensively studied for various applications (intelligent building, medicine, intelligent agriculture, environmental monitoring, aeronautics, aerospace, etc.).

An energy recuperator requires (i) a transducer converting energy from the environment (solar, thermal, chemical, vibratory, etc.) into electrical energy, and (ii) an electrical energy management interface.

EN:

Regarding the ever-increasing number of remote low power sensors, harvesting the energy from the surrounding environment is a pertinent solution to meet the energy needs but reduce the use of conventional batteries. On the one hand chemical batteries are still massively chosen despite their non-negligible cost, their limited lifetime and the pollution they are likely to produce. On the other hand, harvesting ambient energy is a promising alternative to power autonomously and indefinitely remote sensors in addition to process in an eco- friendly way. Solar, thermal and vibrational energies are currently studied and promising for different applications (smart buildings, medicine, agriculture, security issues such as eartquake and fire detection, aeronautic, aircrafts...).

Energy harvesting requires (i) a transducer to convert the environmental energy (solar, thermic, chemical, vibrational...) into electrical energy and (ii) an power management unit (PMU) to extract the maximum energy from the transducer and to convert the electrical signal into the one required by the sensor.

This module will first present various transducers (solar cells, thermogenerators, piezoelements, etc.) and their equivalent electrical model, useful for sizing the electronic interface. This will be followed by a more in-depth study of the management electronics. In particular, the concept of maximum power tracking (MPPT) will be introduced, along with several converters associated with a storage unit. It's important to note that the powers involved range from µW to hundreds of mW, so particular attention will be paid to the energy efficiency of the overall system. 

EN:

This module will first present different types of transducers (solar cells, thermogenerators, piezoelements...) and their electrical modeling useful to design the PMU. Then, we will focus on the PMU and introduce the concept of Maximum Power Point Tracking (MPPT) which is known to be mainly used in photovoltaic modules. Several low-power converters associated to a storage unit will also be studied to adapt and store the harvested voltage. It should be noticed that the power at stake are ranging from µW to several mW and attention will be paid on the PMU efficiency.

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