User's Manual

Page18of52
THEORYOFOPERATION
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SPTFUNDAMENTALS:
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• TheSPTmoduleputsMPPwhereitbelongs,oneverypanel,andproducesthemaximumpowerthatis
availableregardlessofpanelcondition,andregardlessoftheremainderofthesystem.Ifthereispartial
shade,dirtorpanelimbalance,everypanelstillputsoutitsmaximumpower.
• The
SPTmodulereceivesthepowerfromthepanelatMPP.Itdeliversthepowertoanyimpedance
determinedbytheremainderofthestringandtheinverter.Thissolvestheproblemofhavingpanels(current
sources)inseriesbeinglimitedbytheweakestpanelinthestring.
• Theconventionalbulk
powerinvertermayimpressanyvoltageitwantsandbecausetheSPTisdeployedasa
localizedDC‐DCconverter,thepanelfieldwillsimplyoutputMPPfromeverypanel.Thisallowstheinverterto
operateatitshighestefficiencypoint.
• Goingforward,SPTbasedinstallationscanenablebetterbulk
inverterdesignsthatdeliverhigherefficiency,
greaterreliability,smallerandlighterastheywouldnolongerberequiredtoincludeanMPPstage.
• OneofthemostsignificantelementsoftheSPTistheinherentwirelesscommunicationscapabilities,which
enablesinstantaneouscommunicationandcontrol.Theradioandubiquitouswirelessmesh
networkformed
bySPTmoduleswillnotonlyreportpanelvoltage,currentandtemperature,butalsoprovideoperational
benefitsbytogglingthepaneloutputsonandoff.
• Otherinformationcouldalsoresidetheresuchasserialnumberandmanufacturinginformation.
• Thewirelessradiowillalsoprovidediagnosticinformationfor
maintenanceandtrendanalysisthusallowing
intelligentdecisionsonwhatrequiresserviceandwhen.
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TheAmpt SPTisdesignedtomitigateirregularities
betweenthemodulesinanarrayandthebulk
inverter.Specifically,theSPTcanfixitsoutputto
matchtheoptimalinverterinputvoltageand
broadentheperformancerangeofconventional
PVmodules&invertercombinations.Byproviding
localizedDC‐DCconversionalong
withwireless
communication,theSPTenablesinstantaneous
controlandfeedbacktothesystemandthereby
maximizesenergyharvesting.