| 摘要 |
To address at least some of these and other related problems in the prior art, the following invention controls the operation of the device so as, based-on the stored energy at the end of the current energy harvesting period, to regulate power expenditure until the random arrival of the next harvesting period. Regulating of power expenditure respects technological and operationally imposed constraints, like minimum and maximum allowable limit values and possible discrete steps available for choosing power expenditure values in between. The invention provides the methodology, algorithm and implementation steps to optimally trade off between two possible cases: (a) power expenditure is too high leading to energy exhaustion prior to the random arrival of the next harvesting period and (b) power expenditure is unnecessarily low and at the random arrival of the next harvesting period too little residual storage capacity is available to accommodate the energy to be harvested. The amount of energy to be harvested at the next random harvesting interval is also random. To meets its stated goals, the embodiment also includes on line methods to arrive at estimates for both the random length of time durations between energy harvesting and for the random amount of energy available to be harvested. Based on these continuously updated estimates, the trade-off achieved by the algorithm contributes to the safeguard of the availability of a minimal critical operation as well as to an increased overall autarky by avoiding unnecessary unavailability of storage at the energy harvesting intervals. The description of the invention is based on electric electronic autarkic devices with the energy harvester converting energy into electric form and the accumulator absorbing and providing electric energy. The concrete form of internal storage of energy (electrochemical as in batteries, electric charge as in capacitors, combined as in super capacitors, etc.) is left unspecified. The description below explains why a present day electric double-layer capacitor, also known as super capacitor, super condenser, pseudo capacitor, electrochemical double layer capacitor (EDLC), or ultra capacitor, referred below as super capacitor is the preferred energy accumulating device within the framework of the present invention. However applicability of the present invention is confined neither to capacitive energy storage nor to electric autarkic devices. Electronic sensor devices with embedded communication capabilities, networked or stand-alone, if designed for autarky, are presently the prominent representatives of autarkic devices; In other application areas and in different range for device size and magnitude of harvested energy, similar autarky principles can prevail. The present invention is first described for application to general autarkic systems satisfying the conditions specified. Particular representative examples given do not exclude other application areas. |
