Nottingham July 2008Control of AC-DC, HF DC-DC and Automotive DC-DC Converters Power Electronics Research Laboratories, Dept of Electrical and Electronic

Nottingham July 2008 Control of AC-DC, HF DC-DC and Automotive DC-DC Converters

PowerElectronics

Research

Laboratories

Power Electronics Research Laboratories, Dept of Electrical and Electronic Engineering, University College Cork, Ireland

Digital Control of Power Supply Systems with Reduced Standby Digital Control of Power Supply Systems with Reduced Standby LossesLosses

DigiPowerSaveDigiPowerSave

BackgroundBackground

MotivationMotivation

Technology DevelopedTechnology Developed

CommercialisationCommercialisation


PowerElectronics

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BackgroundBackground Regenerative electronic load for testing microprocessor Voltage Regenerative electronic load for testing microprocessor Voltage

Regulator Modules (VRM) developed under Regulator Modules (VRM) developed under PRP/00/PEI/02b, PRP/00/PEI/02b, “High Current/Low Voltage Converters for Environmentally “High Current/Low Voltage Converters for Environmentally Friendly Energy “Friendly Energy “

System demonstrated at IEEE APEC and Electronica.System demonstrated at IEEE APEC and Electronica. Detailed negotiations with companies to license this technology. Detailed negotiations with companies to license this technology.

Elements of this technology are now being commercialised Elements of this technology are now being commercialised demonstrate MOSFET/Drivers.demonstrate MOSFET/Drivers.


PowerElectronics

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2005 MOSFET Demonstrator

Follow-on project due completed in November 2006.Follow-on project due completed in November 2006. Observation: It appears easier to sell “technology Observation: It appears easier to sell “technology

development” than to license technology ?development” than to license technology ?


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Motivation for DigiPowerSaveMotivation for DigiPowerSave

Off-line, or mains-fed power supplies consist of two Off-line, or mains-fed power supplies consist of two parts, parts, a front-end rectifier or ac/dc converter, to draw raw power a front-end rectifier or ac/dc converter, to draw raw power

from the mains from the mains a second precision dc/dc converter to feed the low voltage a second precision dc/dc converter to feed the low voltage

electronic circuits.electronic circuits. Arising out of Arising out of PRP/00/PEI/02bPRP/00/PEI/02b , we had developed digital , we had developed digital

techniques for front-end ac/dc converters. techniques for front-end ac/dc converters. From our experience in industrial motor drive From our experience in industrial motor drive

technology, it was clear that digital control would also technology, it was clear that digital control would also extend to the dc/dc power supply world.extend to the dc/dc power supply world.

Digital control can bring major advantages to both of Digital control can bring major advantages to both of these converter technologies.these converter technologies.


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Potential for Digital Control Potential for Digital Control in Off-Line Power Suppliesin Off-Line Power Supplies

Input AC/DC Converter StageInput AC/DC Converter Stage Standby power in off-line power supplies uses 30W in every home Standby power in off-line power supplies uses 30W in every home

in Ireland.in Ireland.

Up to €35 million, or 5% of residential consumption, is wasted Up to €35 million, or 5% of residential consumption, is wasted every year, resulting in quarter of a million tonnes of COevery year, resulting in quarter of a million tonnes of CO2 2

generated.generated.

Digital control enables the use of non-linear topologies to Digital control enables the use of non-linear topologies to optimise efficiency and minimise standby loss. optimise efficiency and minimise standby loss.

Network communications facilitates remote power supply control. Network communications facilitates remote power supply control.

Output DC/DC Converter StageOutput DC/DC Converter Stage Accurate and precise PWM control.Accurate and precise PWM control. Potential for optimised adaptive control algorithms. Potential for optimised adaptive control algorithms. Reduced sensor requirements.Reduced sensor requirements. Digital communications with front-end ac/dc converter can help in Digital communications with front-end ac/dc converter can help in

overall system efficiency.overall system efficiency.


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Typical power supply unitTypical power supply unit

Objectives:- Objectives:- To address the growing environmentalTo address the growing environmental issue of stand-by issue of stand-by

energy loss and maximise efficiency.energy loss and maximise efficiency. To optimise the advantages of emerging digital control To optimise the advantages of emerging digital control

techniques to produce a tightly controlled dc output voltage.techniques to produce a tightly controlled dc output voltage. Applications include power supplies for a wide range of Applications include power supplies for a wide range of

electronic products.electronic products.


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Innovation in Digital AC/DC Converter Innovation in Digital AC/DC Converter ControlControl

Use of novel topologiesUse of novel topologies Digital technology allows non-linear control strategies Digital technology allows non-linear control strategies

not possible using analogue schemesnot possible using analogue schemes Alternative sensing arrangements can be implementedAlternative sensing arrangements can be implemented Extra magnetics can be eliminated, improving Extra magnetics can be eliminated, improving

manufacturabilitymanufacturability

Special standby modesSpecial standby modes Burst operation when power levels are low Burst operation when power levels are low Introduction of low- power standby functionIntroduction of low- power standby function Reduction of intermediate bus voltage during standbyReduction of intermediate bus voltage during standby

This also increases reliability of electrolytic capacitorsThis also increases reliability of electrolytic capacitors Hold-up capacities can be folded backHold-up capacities can be folded back

ATRP/01/314 DigiPowerSave


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Topology ImplementationTopology Implementation

Two prototypes power supplies were developedTwo prototypes power supplies were developed

A 65W two-switch flybackA 65W two-switch flyback No power factor correction is required below 70W No power factor correction is required below 70W Typical power level for dvd players and set-top boxesTypical power level for dvd players and set-top boxes Supply controlled by DSP on secondarySupply controlled by DSP on secondary Secondary post regulation was used for standby operationSecondary post regulation was used for standby operation

A 200W novel topologyA 200W novel topology 12V output to be cascaded with high spec dc-dc 12V output to be cascaded with high spec dc-dc Typical configuration for computer suppliesTypical configuration for computer supplies DSP on the primary, microcontroller on the secondaryDSP on the primary, microcontroller on the secondary Intermediate bus voltage reduced for standby operationIntermediate bus voltage reduced for standby operation



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65W Two-Switch Flyback65W Two-Switch Flyback

Secondary Side DSP controlSecondary Side DSP control Low power TopSwitchLow power TopSwitchtmtm-fed winding on the same -fed winding on the same

transformer for start-uptransformer for start-up Output filter inductor is used as a buck when in Output filter inductor is used as a buck when in

standby modestandby mode



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Efficiency in Normal ModeEfficiency in Normal Mode


65

70

75

80

85

90

95

0 10 20 30 40 50 60 70 80

Output Power (W)

Eff

icie

ncy

(%

)


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Efficiency in Standby ModeEfficiency in Standby Mode


40.0

45.0

50.0

55.0

60.0

65.0

70.0

75.0

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80

Output Power (W)

Eff

icie

ncy

(%

)


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Power Flow in an Off-Line PSUPower Flow in an Off-Line PSU


Power goes directlyto the output

Power stored inthe bus caps

Power from bus caps

Required Output Power

Power frombus caps

Mains Input Power


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Novel 200W TopologyNovel 200W Topology


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Topology CharacteristicsTopology Characteristics

BenefitsBenefits Only a single magnetic is requiredOnly a single magnetic is required 70% of the power requires only one “conversion”70% of the power requires only one “conversion” No inrush current, no NTC thermister requiredNo inrush current, no NTC thermister required Intermediate bus voltage can be reducedIntermediate bus voltage can be reduced

DrawbacksDrawbacks 2 high-side gate drives required 2 high-side gate drives required Fast recovery rectifier diodes requiredFast recovery rectifier diodes required Primary leakage results in re-circulating energyPrimary leakage results in re-circulating energy Discontinuous currentsDiscontinuous currents


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200W Prototype200W Prototype

Only one custom magnetic componentOnly one custom magnetic component Efficiency 83% to 87%Efficiency 83% to 87%



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Future possibilitiesFuture possibilities The digital strategies and technology The digital strategies and technology

developed in this project could also be developed in this project could also be applied toapplied to Power supplies with integral UPS featuresPower supplies with integral UPS features Integration of small scale generation with a Integration of small scale generation with a

household supplyhousehold supply Solar panelsSolar panels Small wind turbinesSmall wind turbines Micro CHPMicro CHP

Integration of power supplies with building Integration of power supplies with building management systemsmanagement systems



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Power Electronics Research Laboratories, Dept of Electrical and Electronic Engineering, University College Cork, IrelandPower Electronics Research Laboratories, Dept of Electrical and Electronic Engineering, University College Cork, Ireland

•

Digital control in dc-dc conversionDigital control in dc-dc conversion

Divides into two separate applications:Divides into two separate applications: Digital control loop (high-frequency) Digital control loop (high-frequency) System monitoring/interfacing (low-System monitoring/interfacing (low-

frequency) frequency)

Project focus on digital control loopProject focus on digital control loop Development of hardware modulesDevelopment of hardware modules

High-frequency, high-resolution pulse generationHigh-frequency, high-resolution pulse generation Generation of multiple matched and phase-delayed Generation of multiple matched and phase-delayed

signals requiring area-efficient implementationsignals requiring area-efficient implementation FPGA-based architectures with frequency calibration FPGA-based architectures with frequency calibration

capabilitycapability Algorithm developmentAlgorithm development

Observer-based controlObserver-based control


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Generation of multiple high-frequency, high-resolution pulsed digital signals

Reduced cost of current sensors

Project development:

Typical dc-dc buck converter architecture


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•

High resolution pulse generationHigh resolution pulse generation

Delay line approachDelay line approach Minimises required clock Minimises required clock

frequencies frequencies Uses logic gates as delay elements Uses logic gates as delay elements

Difference in time delay between paths Difference in time delay between paths allows very high resolution pulses to be allows very high resolution pulses to be generated.generated.


PowerElectronics

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31

30

1

0

AA=B?

B

Counter

k-bitComparator

d[6:2]

d[m-1:7]

c[k-1:0]

32-ElementDelay Line

Duty Cycle

= Delay Element

Auxiliary Delay LineS

RQ

32:1MUX

d[1:0]

PWM Output

AA=B?

B

k-bitComparator

k'111...11'

mediumfine

coarse

d[m-1:0]

1 2 3 4 5


UCC approach uses 3 delay granularitiesUCC approach uses 3 delay granularities Minimises required implementation areaMinimises required implementation area

Achieves very high resolution (~ 255 ps)Achieves very high resolution (~ 255 ps)


PowerElectronics

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N

31

30

1

0

AA=B?

B

Counter

4 x k-bitComparator

d[3:0][6:2]

d[3:0][m-1:7]

c[k-1:0]

32-ElementDelay Line

R

medium[3:0]

4 xBinary to1-of-N

Decoder

4 xCounter0-to-N

Memory&

Control

DigitalInputs

= 'Resettable' Delay Element

R

R

4 xAuxiliary Delay Line S

RS enableR enable

Q

fine[3:0]

coarse[3:0]

event[3:0]

event[3:0]

4 x32:1MUX

+EdgeDetect

PWM_(1)A

d[3:0][1:0]

2N PWMOutputs

d[3:0][m-1:0]

0

500

1000

1500

2000

2500

0 2 4 6 8 10 12 14 16

Number of DPWM phases (=N)

No. o

f LUTs

Novel area-efficient multi-phase architecture

Non-optimized architecture

Single output


Architecture expanded to generate multiple outputsArchitecture expanded to generate multiple outputs Phased nature of outputs used to reduce Phased nature of outputs used to reduce

implementation area compared to non-implementation area compared to non- optimised optimised architecturearchitecture


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Commercialisation ICommercialisation I

Two digitally controlled PSU’s have been developedTwo digitally controlled PSU’s have been developed A 65W supply for set-top box applicationsA 65W supply for set-top box applications A 200W single magnetic unit with integrated power factor A 200W single magnetic unit with integrated power factor

correction.correction.

Intellectual propertyIntellectual property Novel single magnetic topologyNovel single magnetic topology Application of state space methods to PSU controlApplication of state space methods to PSU control

Potential for commercialisationPotential for commercialisation Discussions with large IC company regarding PSU digital Discussions with large IC company regarding PSU digital

control.control. Support for Irish power supply companies wishing to Support for Irish power supply companies wishing to

incorporate digital control into their productsincorporate digital control into their products Licensing of novel topology to be further explored.Licensing of novel topology to be further explored.



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Commercialisation IICommercialisation II

June, 2005, 'A digital PWM controller for multi-June, 2005, 'A digital PWM controller for multi-phase dc/dc converters' (DigiPowerSave). This phase dc/dc converters' (DigiPowerSave). This patent was allowed to lapse as it was not patent was allowed to lapse as it was not licensed. licensed.

Discussions with large IC companies regarding Discussions with large IC companies regarding the use of high resolution PWM generationthe use of high resolution PWM generation



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The comparative non-isolated bi-directional dc-dc converter The comparative non-isolated bi-directional dc-dc converter analysis analysis

Marek RylkoMarek Rylko


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Aim of the workAim of the work

Comparative half-bridge bi-directional Comparative half-bridge bi-directional high-power dc-dc converter analysishigh-power dc-dc converter analysis Switching regimes (soft and hard switching)Switching regimes (soft and hard switching) Switching devices (MOSFET, IGBT, diode)Switching devices (MOSFET, IGBT, diode) Materials (silicon, SiC, GaN)Materials (silicon, SiC, GaN) Operating frequency limitsOperating frequency limits Volume and cost analysesVolume and cost analyses

Magnetic designMagnetic design An inductorAn inductor An transformerAn transformer


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IntroductionIntroduction

The hi-power dc-dc converter applicationThe hi-power dc-dc converter application Automotive (power train)Automotive (power train) Battery chargersBattery chargers Fuel Cell stationary generators Fuel Cell stationary generators Wind turbines (potentially)Wind turbines (potentially) Electric crafts Electric crafts

Battery SuperCap

DC-DC

Converter

Regenerative

Load


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The Power RequirementThe Power Requirement

Power requirement depends on design Power requirement depends on design i.e.:i.e.:

The automotive application for mid-size C The automotive application for mid-size C class car 100kW peak for 30sec and 50kW class car 100kW peak for 30sec and 50kW continuous power – competitive continuous power – competitive performance to present ICE carsperformance to present ICE cars

The battery charger - maximum charging The battery charger - maximum charging current and voltage (charging regimes)current and voltage (charging regimes)

Consideration of the work-cycle is important Consideration of the work-cycle is important to avoid an overestimated designto avoid an overestimated design


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The Power SupplyThe Power Supply

The internal combustion engine with generator (gasoline, The internal combustion engine with generator (gasoline, diesel, CNG, LPG, hydrogen, methanol)diesel, CNG, LPG, hydrogen, methanol) Pollution (NOPollution (NOxx, CO and CO, CO and CO22)) Crude Oil shortageCrude Oil shortage

The fuel cellThe fuel cell Zero emission (excluding hydrogen production) Zero emission (excluding hydrogen production) Refuelling problem, low social acceptanceRefuelling problem, low social acceptance Short Cycle LifetimeShort Cycle Lifetime

The batteryThe battery Well established technology, clean but expensive and Well established technology, clean but expensive and

requires complex production process, contains toxic requires complex production process, contains toxic components, recycling problemcomponents, recycling problem

The solar panelThe solar panel Low power density, solar radiation dependentLow power density, solar radiation dependent


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The Car Power TrainThe Car Power Train

Classical solutions with IECClassical solutions with IEC Hybrid propulsion systems (IEC and electric Hybrid propulsion systems (IEC and electric

motor)motor) Series HybridSeries Hybrid Parallel HybridParallel Hybrid Series-ParallelSeries-Parallel Complex HybridComplex Hybrid

The battery electric vehicleThe battery electric vehicle The fuel cell electric vehicleThe fuel cell electric vehicle


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The Hybrid Car ClassificationThe Hybrid Car Classification


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The Fuell CellThe Fuell Cell

Fuell Cell types and propertiesFuell Cell types and properties Types PEM, AFC, PAFC, MCFC, SOFCTypes PEM, AFC, PAFC, MCFC, SOFC fuel cell operates best at a 30 percent load factorfuel cell operates best at a 30 percent load factor due to issue due to issue

of mass transport limitation (oxygen and hydrogen contact with of mass transport limitation (oxygen and hydrogen contact with membrane)membrane)

Ironically, the fuel cell does not eliminate the battery – it Ironically, the fuel cell does not eliminate the battery – it promotes it. promotes it.

The The fuel cell needs batteries as a buffefuel cell needs batteries as a buffer.r. Efficiency up to 65%Efficiency up to 65% at 30% of load (efficiency is output at 30% of load (efficiency is output

power reffered to LHV – includes water vaporisation)power reffered to LHV – includes water vaporisation) Complex auxiliary components systemComplex auxiliary components system Auxiliary system requires 10-15% of FC rated powerAuxiliary system requires 10-15% of FC rated power High costHigh cost


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The Battery - types and propertiesThe Battery - types and properties Types: Types: Valve Regulated Lead Acid Valve Regulated Lead Acid (VRLA), NiCd, NiZn, NiMH, (VRLA), NiCd, NiZn, NiMH,

Zn/Air, Al/Air, Na/S, Na/NiClZn/Air, Al/Air, Na/S, Na/NiCl22, Li-Polymer, Li-ion, , Li-Polymer, Li-ion, High efficiency up to 99% (Li-ion polymer exclude converter)High efficiency up to 99% (Li-ion polymer exclude converter) Zero emission (energy generation not included)Zero emission (energy generation not included) Specific energy 330Wh/kg Li-ion superpolymer ElectrovayaSpecific energy 330Wh/kg Li-ion superpolymer Electrovaya Specific power 315W/kg at 80% discharge rate (Li-ion polymer)Specific power 315W/kg at 80% discharge rate (Li-ion polymer) Energy density 600Wh/liter Li-ion superpolymer ElectrovayaEnergy density 600Wh/liter Li-ion superpolymer Electrovaya High cost (>100€/kWh Li-ion)High cost (>100€/kWh Li-ion) Short lifetime (800-1200 at 80% discharge rate Li-ion) or 3-7 Short lifetime (800-1200 at 80% discharge rate Li-ion) or 3-7

yearsyears Toxic component – needs recycling policyToxic component – needs recycling policy Battery terminal voltage varies with state of charge and Battery terminal voltage varies with state of charge and

discharge current (1.6-2.4V for VLRA, 3-4V for Li-ion)discharge current (1.6-2.4V for VLRA, 3-4V for Li-ion) Charging issuesCharging issues Super CapacitorSuper Capacitor

BatteriesBatteries


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The LoadThe Load

4-quadrant inverter with electric motor4-quadrant inverter with electric motor Energy recoveringEnergy recovering Energy conditioning for double-fed induction Energy conditioning for double-fed induction

motormotor


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The ConverterThe Converter

Isolated – push and pull, full bridgeIsolated – push and pull, full bridge Non-isolated – half-bridge buck-boost, cascade, buck, Non-isolated – half-bridge buck-boost, cascade, buck,

boost, CUK, Sepic/Luo, voltage multipliers (magnetic-boost, CUK, Sepic/Luo, voltage multipliers (magnetic-less)less)

Hard switched (HS)Hard switched (HS) Soft switched (SS)Soft switched (SS) SimplicitySimplicity Bi- and uni-directionalBi- and uni-directional Advantages and disadvantagesAdvantages and disadvantages

Non-isolated SS converter Isolated converter

Non-isloated HS converter


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Hard and Soft SwitchingHard and Soft SwitchingThe Hard Switching

The Soft Switching

Switching losses limit the maximum operating switching frequency and may result in significant device derating.

The soft switching constrains the switching of the power devices to time intervals when the voltage across the device or the current through it is nearly zero.


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Semiconductor DevicesSemiconductor Devices

MaterialsMaterials SiliconSilicon Silicon Carbide (SiC)Silicon Carbide (SiC) Gallium(III) Nitride (GaN)Gallium(III) Nitride (GaN)

DevicesDevices MOSFET MOSFET (CoolMOS)(CoolMOS)

IGBT IGBT (Trench, Planar)(Trench, Planar)

BJTBJT ThyristorThyristor


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MagneticsMagnetics

InductorInductor High inductance dc inductor with small ac-High inductance dc inductor with small ac-

component – small current ripplecomponent – small current ripple Low inductance dc inductor with high ac-Low inductance dc inductor with high ac-

component – high current ripplecomponent – high current ripple TransformerTransformer

Magnetising inductance issueMagnetising inductance issue Power loss associatedPower loss associated

Core (histeresis, eddy currents)Core (histeresis, eddy currents) Windings (eddy currents – skin and proximity Windings (eddy currents – skin and proximity

effect)effect)


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Soft-Switching ConverterSoft-Switching Converter

The converter has been made by The converter has been made by adding an auxiliary cell to the adding an auxiliary cell to the

classical half-bridge bi-directional classical half-bridge bi-directional converter.converter.


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Soft-Switching ConverterSoft-Switching Converter

The presented soft-switched converter is quasi-The presented soft-switched converter is quasi-resonant with an auxiliary commutation cellresonant with an auxiliary commutation cell

Benefits of solution are:Benefits of solution are: Use intrinsic MOSFET body diodesUse intrinsic MOSFET body diodes High efficiency over a wide load range up to 97.6%*High efficiency over a wide load range up to 97.6%* High operating frequency leading to size reductionHigh operating frequency leading to size reduction Very robust, topology ensuring safe operating Very robust, topology ensuring safe operating

region by hardware designregion by hardware design Works above audible frequency 100kHzWorks above audible frequency 100kHz

DisadvantagesDisadvantages More elements than classical solutionMore elements than classical solution Auxiliary signalsAuxiliary signals Complicated design processComplicated design process

*For V1/V2 = 0.5


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The Duty Cycle AnalysisThe Duty Cycle Analysis

The converter is assumed to operate under fixed bus The converter is assumed to operate under fixed bus voltage conditions and the converter average output voltage conditions and the converter average output current gain is investigatedcurrent gain is investigated

The pole-voltage wave shape is affected by the turn-on The pole-voltage wave shape is affected by the turn-on and turn-off mechanismsand turn-off mechanisms

The converter current gain can differ significantly from The converter current gain can differ significantly from the idealised HS casethe idealised HS casePole voltage

SS cell

HS ideal


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The Duty Cycle Numerical VerificationThe Duty Cycle Numerical Verification

HS

SS

The HS and the SS case differs due to SS V·s loss

Gray points represents PSpice™ simulation results


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Converters comparisonConverters comparison

Three converters have been built and testedThree converters have been built and tested Soft-switched MOSFET based – low rippleSoft-switched MOSFET based – low ripple

Hard-switched MOSFET based – high rippleHard-switched MOSFET based – high ripple


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Converters comparisonConverters comparison Hard-switched IGBT based – low rippleHard-switched IGBT based – low ripple

ParameterSS MOSFET

HIGH-RIPPLE MOSFET

HS IGBT

Rated power 1.25 kW 1.25 kW 1.25 kWV1 125 V 125 V 125 V

V2 250 V 250 V 250 VL 200 H 28 H 200 Hf 100 kHz 100 kHz 100 kHzI 3.1 A 22 A 3.1 AIAVG 10.0 A 10.0 A 10.0 APeak Eff. 97.6% 97.4% 96.5%

Table I. Converters comparison


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Converters comparisonConverters comparison

Switching DevicesSwitching Devices MOSFET - MOSFET - Infineon type Infineon type SPW47N60 SPW47N60 (CoolMOS™)(CoolMOS™) IGBT - IGBT - International Rectifier type International Rectifier type IRGP50B60 (WARP2)IRGP50B60 (WARP2) Auxiliary MOSFET - Auxiliary MOSFET - Infineon type Infineon type SPP12N50C3SPP12N50C3 (CoolMOS™) (CoolMOS™)

InductorsInductors Low-ripple inductor made of solid wireLow-ripple inductor made of solid wire

ø1.5mm, 19 turns, 200ø1.5mm, 19 turns, 200H, core EE65,H, core EE65,

material 3F3, total airgap 1.44mmmaterial 3F3, total airgap 1.44mm High-ripple inductor made of Litz wire High-ripple inductor made of Litz wire

25xø0.315mm, 7 turns, 2825xø0.315mm, 7 turns, 28H, core H, core

EE65, material 3F3,EE65, material 3F3,

total airgap 2.38mmtotal airgap 2.38mm


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Converters comparison - resultsConverters comparison - results


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The Test RigThe Test Rig

Main pole

Inductor

The Soft-switching cell

Control board


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The Soft-Switching CellThe Soft-Switching Cell


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The Main PoleThe Main Pole


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The Control BoardThe Control Board

Based TMS320F2808


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ConclusionsConclusions

Bi-directional converters have been investigated onlyBi-directional converters have been investigated only The three converters, which have been presented, achieve The three converters, which have been presented, achieve

high efficiency of order 96-97% over a wide load rangehigh efficiency of order 96-97% over a wide load range Low-ripple HS MOSFET on test shows efficiency of order 88% Low-ripple HS MOSFET on test shows efficiency of order 88%

due to the poor intrinsic diodedue to the poor intrinsic diode The IGBT transistor with the soft-switching cell The IGBT transistor with the soft-switching cell did not did not

demonstrate any significantdemonstrate any significant efficiency efficiency improvements improvements The HS-converters with the IGBT transistors are preferred at The HS-converters with the IGBT transistors are preferred at

frequencies up to 150kHz due to lower cost and simplicityfrequencies up to 150kHz due to lower cost and simplicity Beyond 150kHz MOSFETs indicates superiority over IGBTsBeyond 150kHz MOSFETs indicates superiority over IGBTs High-ripple converter, despite great efficiency results, cause High-ripple converter, despite great efficiency results, cause

serious challenge for magnetic design due to significant serious challenge for magnetic design due to significant current AC componentcurrent AC component


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Continuing workContinuing work

Converters comparison at higher frequency 200kHz-Converters comparison at higher frequency 200kHz-500kHz500kHz

IGBT operation frequency limits under hard and soft IGBT operation frequency limits under hard and soft switching regimeswitching regime

A uni-directional dc-dc converter comparison with A uni-directional dc-dc converter comparison with different switching devices at 100kHz-500kHz different switching devices at 100kHz-500kHz (IGBT+Si/SiC, MOSFET+Si/SiC)(IGBT+Si/SiC, MOSFET+Si/SiC)

Inductor design for the converter at 100kHz-200kHz Inductor design for the converter at 100kHz-200kHz and 100kWand 100kW

Cost analysisCost analysis Interleaved converterInterleaved converter


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The EndThe End

Thank you for your attention.Thank you for your attention.

Documents

Nottingham July 2008Control of AC-DC, HF DC-DC and Automotive DC-DC Converters Power Electronics Research Laboratories, Dept of Electrical and Electronic