Panasonic NN­GS595A - 2 DESCRIPTION OF OPERATING SEQUENCE; 2.1 Variable Power Cooking Control; 2.2 Inverter Power Supply Circuit; 2.3 Steam Defrost, Auto Cook & Steam Reheat

10/24/2016 XMLServiceManual
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2DESCRIPTIONOFOPERATING
SEQUENCE
2.1Variablepowercookingcontrol
HighVoltageInverterPowerSupply(U)controlsoutputpowerbythesignalfromDigitalProgrammerCircuit(DPC).Powerrelay
alwaysstaysON,butPWM(pulsewidthmodulation)signalcontrolsmicrowaveoutputpower.
NOTE:
TheON/OFFtimeratiodoesnotcorrespondwiththepercentageofmicrowavepowersinceapproximately2secondsare
requiredforheatingofmagnetronfilament.
VariablePowerCooking
POWER
SETTING
OUTPUTPOWER(%)
APPROX.
MANUALMICROWAVEDUTY
ON(SEC) OFF(SEC)
HIGH 100% 22 0
MEDIUMHIGH 70% 22 0
MEDIUM 55% 22 0
MEDIUMLOW 40% 22 0
LOW 20% 13 9
DEFROST 30% 17 5
2.2InverterpowersupplycircuitNEWH.V.
TheInverterPowerSupplycircuitpoweredfromthelinevoltage,220V50HzACinputsupplies4,000VDCtothemagnetrontube,
andfunctionsinplaceoftheH.V.transformer,theH.V.capacitorandH.V.diode.
1.TheACinputvoltage220240V50HzisrectifiedtoDCvoltageimmediately.
2.DCvoltagewillbesuppliedtotheswitchingdevicescalledIGBT.ThesedevicesareswitchedONOFFbythe20to40
KHzPWM(pulsewidthmodulation)signalfromthemicrocomputerintheDPC.
3.ThisdrivestheHighvoltagetransformertoincreasevoltageupto2,000VAC.
4.Thenthehalfwavedoublervoltagerectifiercircuit,consistingoftheH.V.diodesandcapacitors,generatesthe
necessary4,000VDCneededforthemagnetron.
5.Outputpowerofthemagnetrontubeisalwaysmonitoredbythesignaloutputfromthecurrenttransformerbuiltintothe
invertercircuit.
6.ThissignalisfedbacktothemicrocomputerintheDPCtodetermineoperatingconditionsandoutputnecessaryto
controlPWMsignaltotheInverterPowerSupplyforcontroloftheoutputpower.
2.3Steamdefrost,Autocook&Steamreheat
WhentheAutoControlfeatureisselectedandtheStartpadistapped:
1.Thedigitalprogramercircuitdeterminesthepowerlevelandcookingtimetocompletecookingandindicatesthe
operatingstateinthedisplaywindow.Tableshowsthecorrespondingcookingtimesforrespectiveservingby
categories.
SteamDefrost
SELECTEDWEIGHT COOKINGTIME
1.0kg 15min.20sec.
AutoCook(Rice)
SELECTEDWEIGHT COOKINGTIME
0.2kg 20min.00sec.