Energy Storage Needs
In order to power systems using ambient energy harvesting, several factors must taken into consideration to calculate the power required to operate the system in various states:
1 - Identify the sources of ambient energy to be used and the type of Energy Harvesting transducer to be used
2 - Characterize the power output of the EH transducer over various ambient conditions
3 - Looking at all the system components, calculate the power required for all states operation (e.g. sleep, sensing, wireless)
4 - Identify the EH conversion and power management electronics to be used and add the power used to the overall total.
5 - Size the energy storage device (solid state battery) to cover all the system energy storage and power delivery requirements.
Reference schematics of these systems can be found in the Cymbet EVAL-09 datasheet and the EVAL-10 data sheet.
Using Maximum Peak Power Tracking
To optimize the performance of energy harvesting based systems, it is critical the high efficiency energy conversion technique of maximum peak power tracking (MPPT) be used. MPPT can adapt to either constant impedance or variable impedance EH transducers. MPPT is used to match the impedance between the energy harvesting transducer and the system load as seen in the diagrams below. The EnerChip EP Energy Processor CBC915 implements an optimized version of MPPT.
Energy Transaction Calculations
he definition of an energy transaction is "the amount of discrete energy required to perform a certain task or functional transaction". This concept of energy transaction is very useful in the design of energy harvesting-based systems. In order to calculate the power budget and power boundary conditions for an EH-based system, all operating and quiescent power states of the system must identified. Each of these states requires an energy transaction level to function. Identifying all the various energy transactions will determine the sizing of the Energy Harvesting transducer and the energy storage devices.
Designing electronics for compact, small footprint systems requires the use of new advanced technologies such as the EnerChip CBC915 Energy Processor and the EnerChip CBC050 Solid State Battery. These space saving devices can be surface mounted anywhere on a PCB and reflow soldered. EnerChip solid state batteries last the life of the product so they never have to be changed.
EnerCard EH modules can be used in many systems such as Energy Harvesting-powered systems, Wireless Sensors, and tiny Internet of Things solutions.