Tuesday,April25,2023

03:00pmCEST|EMEAsession

02:00pmEDT|Americassession

ActiveDischargeandPre-chargeofEVHighVoltagePowerBus

2

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ActiveDischargeofEVHighVoltagePowerBus

1

WhydoweneedtodischargeHVBus?

2

HowcanwedischargeHVbus?

3

BenchmarkingDischargeSwitch

4

WhyusingTHYRISTOR?

5

6

7

8

THYRISTORProductrange

ReferenceDesignforHVBusdischarge

Howtodiagnosethedischargefunction?

LivedemoofDiagnosticandHVbusDischarge

ll·E.augmented

BMSActiveDischargewithTHYRISTOR

FastDischargepreventsFirehazard

IncriticaleventstheHVsystemshallbeactivelydischargedtopreventshortcircuitfireandelectricalshocksbyresidualvoltage.

Thebatteryvoltageisdisconnectedbyaseparatedisconnectionunit.

AllDCCapacitorsaredischargedinpowerresistorswithminimalvalueinordertominimizethedischargetime

3

SafetyRequirementinISO-6469specifydischargeinlessthan10sbutSCRDischargeinfewmillisecondswilllimittheriskofFire.

ISO6469-Part4

Postcrashelectricalsafety

400V

80

DC-Link

VOLTAGE

60

Timeto60VRDischargeCurrent

Fewms(shorterisbetter)

MinimizePowerresistorvalue

(smallerisbetter)

Batterydisconnected

VDC

SafeArea

5s

Vehiculestops

DClinkCapacitordischarge

DC-LinkVOLTAGE0V

10s

tmTime

Initialimpact

Invertercurrent

decreasetozero

(50A0A)

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HVCapacitivedischarge

SWITCHBenchmark

FOCUS

A

G

K

IGBT/MOSFET

Close/Open

Multiple

OPEN

<100A

6.5x9.7x2.3mm

PyroSwitch

CloseSingleSHORT5000A

25x30x60mm

SwitchDischarge

FailsPeakCurrent

Size

Price

THYRISTOR

Close

Multiple

SHORT

Upto3000A

6.5x9.7x2.3mm

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WhyusingSCRforHVdischarge?

SCRHigherpeakCurrent

MOSFET&IGBTareturnedONwithGateVoltage

MOSFETPeakcurrentwillbelimitedbySaturationregionIGBTPeakcurrentwillbelimitedbylinearMode

SCRislatchedbyGatecurrentpulse

OncetheSCRislatched,gatecurrentcanberemoved

SCRPeakcurrentismuchhigherthanMOSFETorIGBT

ForHVCapacitiveDischarge,onlySCRareabletosupport>2000A@1ms

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WhyusingSCRforHVdischarge?

300A

2

1

3

SafeOperatingArea(IGBTexample)isdefinedby

1Collector-EmiterSaturationvoltage(VCEsat)

2MaximumCollectorCurrent

3Thermallimit(Maxjunctiontemperature)

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WhyusingSCRforHVdischarge?

Figure7.Nonrepetitivesurgepeakon-statecurrent

2

4000A

1

3

SCRhasaspecificationforNonrepetitiveCurrent

4000AforPeakCurrentof0.1ms2000AforPeakCurrentof1ms600AforPeakCurrentof10ms

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BMSHVCapacitorDischarge

dedicatedSCRProducts

BatteryVoltage

DischargeEnergy

DischargeResistance

SCRPN#

BreakdownVoltage

PeakCurrent

CurrentrisedI/dt

Package

400V

300Joules

>0.2Ohms

>800V

<2000A

<450A/μs

D2PAK

TN4035HA-8

800V

1100Joules

>0.2Ohms

>1200V

<4000A

<450A/μs

TO247

TN13050HA-12

Pre-productionrelease

ESreleaseApr‘23

DischargePowerResistors

G

1100J0.6Ω

1000J0.2Ω

90J3Ω

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A

K

THYRISTORHighCurrentclipassemblyD2PAK

TO-247

STDES-DIS001EvaluationBoard

400VBatteryTN4035HA-8

MidPoint

Discharge

GND

GND

LSSCR

IsolatedSupply

PowerResistor+12VHSSCR

Boostrapdiode

MidPointMCUControlPowerResistor

LS/GND/HS

control

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CAPACITOR

3mF

Diagnostic

400V

400V400V

POWERRESISTOR

0.2Ω

1000Joules

LSclose

HSclose

LSclose

HSclose

Switchingfrom0Vto400V

0V0V

0V

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CapacitivedischargeDiagnostic

500V,2.25mF,0.3Ohms

CapVoltage

MidPointHIGH

MidPointLOW

HSControl

LSControl

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ll·fE.augmented

CAPACITOR

3mF

400V

POWERRESISTOR

0.2Ω

1000Joules

Discharge

0V

DischargeI

400V

DischargeCurrent

50V

990JoulesCapacitiveDischarge

850V,2.75mF,0.2Ohms

3750APeak

850V

1.5ms

50V

290A/μs

SCRtrigger

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Pre-chargeofEVHigh

VoltagePowerBus

DFDToursApril2023

ll·fE.auente

16

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Pre-chargeofEVHighVoltagePowerBus

1

Whydoweneedtopre-chargeHVBus?

2

Howtoimplementpre-chargewithThyristor?

3

Benchmarkingpre-chargeSwitch

4

Whatarethebenefitsof

THYRISTORpre-charge?

5

6

7

8

RecommendedSCRschematiccontrolforprecharge

HowtodetectHVBusdefault?

WebinarTakeAway

THYRISTORProductrange

ActivePre-chargewithTHYRISTOR

Apre-chargecircuitisusedtopreventstressanddamagetotheelectricsystembyimplementingaresistorandaswitchtolimitin-rushcurrent

Pre-chargeRelayareusuallyElectro-mechanicalcontactorusedinBatteryManagementSystem(BMS)andPowerdistributionUnit(PDU)

SCRcanreplacetraditionalpre-chargedRelayforamorereliable,smaller,andmoreresponsiveSolidStatesolutioncomparedto

mechanicalcontactswhichcanwearoutovertime.

17

ie.7ugrnsnieci

LimitIn-rushCurrentwithTHYRISTOR

18

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PDUfunctionalitydescription

Pre-chargemode

?SCR1&RELAY2are

switchedONtochargeinputcapacitancethroughthepre-chargeresistance

?RELAY1isturnedONafterprecharge

Steadystatemode

?BothrelaysareswitchedONtotakeoverthecurrentconduction

?SCRswitchedOFFautomaticallysincethecurrentbecomeslowerthantheholdingcurrentIH

Dischargemode

?RelaysasswitchedOFFtodisconnecttheBattery

?SCR3isswitchedON,aftertherelaysareOPEN,todischargetheCapacitancethroughthe

powerresistance

Solidstateswitchesbenefits

Mechanicalrelays

?Slowswitchingspeed

?LargesizeoccupationonthePCB

?Highpowerconsumption

?Limitedlifespanduetothedegradationofthemechanicalcontacts

?EMIandnoisegeneratedduetomechanicalcontactbouncing

?Firehazardduetoarcingbetweencontacts

?MetalcontactsaresubjecttoWelding

Solidstateswitches

?Fastswitchingtime

?Highpowerdensityhandlinginmorecompactpackages

?Smallerandthinnerformfactor

?Higherreliabilityandincreaseofthelifespanbyreplacingmechanicalcontact

?Lowerpowerconsumption

?Safersolutionwithoutcontactarcing

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Pre-chargeresistorsimpact

onPre-chargeduration1/2

2mΩ

850V

2mΩ

3mF

Pre-chargedesignexample

?Thepre-chargeresistorvaluehasakeyroleatdefiningthepre-chargedurationtime.

?Thehighertheresistance,theslowerthepre-charge.

?TheLowertheresistance,theHigherthecurrent.

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Pre-chargeresistorsimpact

onPre-chargeduration2/2

2mΩ

850V

2mΩ

3mF

Pre-chargedesignexample

?Pre-chargecurrentisgoingthroughtheSCR(Pinkbars)

?SCRmustbeselectedaccordingtothepre-chargeresistance

?Afterpre-charge,theSCRwillautomaticallyturnOFFoncetheRELAY1isON

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Pre-chargeresistor’simpact

onpeakcurrent

2m?

850V

2m?

3mF

Pre-chargedesignexample

?Thankstoitshighcurrentconductioncapability,SCRscanconducthighcurrentduringsmalltimeduration

?WhenPre-chargeresistorvalueisbelow1?,therelaycanbeturnedONwhentheSCRhasreachedtheturn-offcurrent

?SCRsenableusingsmallerpre-chargeresistors

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Pre-chargeSCRscontrolsuggestions

DistributionUnit

RELAY1preventsleakagecurrentinDisconnectMode.

SW1isusedtodetectSHORTcircuitonHVDCBus.

CapacitorischargingthruSW1thatisactivatedbyMCU.

RELAY1

WhentheHVDCBusisnotshorted,SCR2canbelatchedONtoenablePre-chargesafely.

AfterPre-charge,RELAY2willbeturnedONandSCR2willunlatchasallcurrentflowthrutherelay.

Mode

RELAY1

SW1

SCR2

RELAY2

SCR3

Disconnect

OFF

OFF

OFF

OFF

OFF

SHORTdetection

ON

ON

OFF

OFF

OFF

Pre-charge

ON

OFF

ON

OFF

OFF

SteadyState

ON

OFF

OFF

ON

OFF

FastDischarge

OFF

OFF

OFF

OFF

ON

Power

SCR3

SCR2

SW1

D2PAKTO-247

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ShortCircuitdetectionbeforepre-charge

SW1

Short-circuitDetection

SCR2Pulse

SteadyState

Relay2ON

Pre-charge

24

TAKEAWAY

G

A

K

ActiveDischargeandPre-charge

ofEVHighVoltagePowerBus

400VBATTERY

SCRPN#

BreakdownVoltage

PeakCurrent

CurrentrisedI/dt

Package

Pre-chargeR>0.2Ohms

TN4035HA-8*

>800V

<2000A

<450A/μs

D2PAK

DischargeR>0.2Ohms

TN4035HA-8*

>800V

<2000A

<450A/μs

D2PAK

*Productionpre-release

800VBATTERY

SCRPN#

BreakdownVoltage

PeakCurrent

CurrentrisedI/dt

Package

Pre-chargeR>0.2Ohms

TN13050HA-12*

>1200V

<4000A

<450A/μs

TO247

DischargeR>0.2Ohms

TN13050HA-12*

>1200V

<4000A

<450A/μs

TO247

*Engineeringsamples

ll·fe.augmented

D2PAK

TO-247

ST’sReferenceDesign

STDES-DIS001Colaterals

BoardSchematic

BoardLayout

KEYFEATURES

?ActiveDischargeSCRfor400Vbattery.

?ReferencedesignforDIAGNOSTIC&DISCH