AnAdaptive MaximumPowerPoint Tracker for Maximising Solar CellEfficiency inWireless Sensor Nodes

Thesuccess ofwireless sensor networks issomehow To overcome these problems andoptimally exploit the related totheenergy supply which, generally provided bybatteries, energy generated byasolar cell thesingle diode circuit must isafinite resource. Energy scavenge mustbepursuit togrant longbereplaced withamaximumpowerpoint tracker (MPPT) time operation andsolar energy issurely themosteffective onedue circuit which, forwireless sensor units, mustbesuitably toitsubiquitous distribution andrelatively high powerdensity. In designed tominimize itspowerconsumption. MPPT circuits this paperwe propose a maximumpowerpoint tracker circuit .. p (MPPT) forwireless nodes, i.e., a powerconverting circuit fornare specal powercircuits abletotransport energy generated optimally transferring solarenergytorechargeable batteries; inside atsarncllinnto a orage elmnt, like aebatrywh efficiency isgranted byanadaptive algorithm whichkeeps the aiming atmaintaining theworking point ofthecell around MPPTinits optimal working point bytracking solar radiation soas theoptimal one(maximizing thetransferred power). tomaximise theenergy generation andtransferflow. Inthis paperwe suggest anovelimplementation ofan adaptive digitally controlled MPPT circuit especially Keywords -MPPTcircuit, solar energy, wireless sensor networks designed forwireless sensornodes. Thedesign process has beencarried outbearing inmindtherequests ofthe I.INTRODUCTION embedded target device: lowcost, highefficiency, lowpower Theneedofscavenging energy inwireless sensor networks is consumption andadaptation tochanging light conditions. Thestructure ofthepapzer iSasfollows. Section IIaddresses aprimary issue tobeaddressed togrant effectiveness ofthe isestreltue totheMpap circi section IIproestes techoloy ia wde pecrumofapliatins.espte he ssuesrelated totheMPPT circuit; section IIIproposes the technology inawidespectrum ofapplications. Despite the adptv diia coto.ehiu o takn h pia fact that different energy sources exist (1), themosteffective working pint;onpesents e rint al forthehigh powerdensity obtainable isthesolar one. - , Unfortunately, solarcells exhibit a strong non linear II. DESIGINGAN ADAPTIVEPOWER CONVERTER electrical characteristic whichmakesitdifficult toefficiently extract energy. Moreover, suchcharacteristic isstronglyA MPPT circuit isessentially composed oftwomain influenced bytheillumination condition (angle ofincidence parts: aninput voltage-controllable