EUROPEAN GT CONFERENCE 2019 - gtisoft.com · European GT Conference 2019 –Frankfurt 2019 G. Boccardo, E. Graziano, L. DeRosa, T. Mrkvica, S. Pautasso –Virtual BEV Thermal Control

Virtual BEV thermal management control development by

means of an integrated GT-SUITE model of HVAC and

battery cooling circuits

G. Boccardo1, E. Graziano1, L. De Rosa1, T. Mrkvica2, S. Pautasso3

1: POWERTECH Engineering Srl, Turin – ITALY

2: Sattelo S.r.o – CZECH REPUBLIC

3: Diesel Emission Control L.t.d. - UK

EUROPEAN GT CONFERENCE 2019

October 7, 2019 - Frankfurt am Main, Germany

Page 2European GT Conference 2019 – Frankfurt 2019 G. Boccardo, E. Graziano, L. DeRosa, T. Mrkvica, S. Pautasso – Virtual BEV Thermal Control Development

Agenda

1. Introduction

2. Cooling System Layout & Model Overview

3. Control Strategy Overview

4. Model Setup

5. Results Assessment

6. Conclusions and Next Steps


Agenda

1. Introduction



4. Model Setup




1. Introduction

Source: Hertzke P, Müller N., Schenk S., Wu T., "The global electric-vehicle market is

amped up and on the rise". McKinsey & Company (May 2018). Retrieved 2019-05-13

Motivations

• Global EV/PHEV market share has

exponentially grown in the last decade

• Electrified powertrains bring new design

concerns and tradeoff for the thermal

conditioning systems:

– Component Protection

Fire/Explosion Hazard

Aging

– Performance

De-Rating Strategies

– Cabin comfort

Active cooling thermal budget

– Range

Energy cost for thermal conditioning

COOLING

AIR CONDITIONING


Aim / Constraints

Design a BEV thermal management strategy to coordinate the actuations of:

• Heater Circuit

• Passive Cooling Circuit

• Active Cooling Circuit (A/C)

• Cabin Evaporator

• Battery Chiller

1. Introduction

-20°C 10°C 25°C 35°C

Battery Pack Operative Temperature

Target Area

Optimal Ratio

Performance/Aging

Derating Strategy

Only Discharge Mode

Permitted

15°C 45°C 60°C

Derating Strategy

Only Discharge Mode

Permitted

Full Performance Area

Charge/Discharge Mode Permitted

→ To maintain the battery coolant temperature in the optimal temperature range and

with a maximum inlet-outlet temperature difference of 5°C with the minimum impact

on cabin comfort


Controller / Plant Coupling

• MiL Approach

– GT-SUITE plant model outputs represent the measures from the

different sensors placed along the model

– Simulink model outputs represent the signals governing the actuators

placed in the plant model

1. Introduction

To A

ctuato

rs

From

Sens

ors

CONTROLLER

PLANT

MOTIVATIONS:

• Fully physical plant

model

• Co-Simulation

Available on a

common Desktop PC

• No need of physical

hardware


Agenda

1. Introduction



4. Model Setup




Overview: Cooling system design study for a premium BEV

• Coolant Circuit (50% Water / 50% Glycole): Heating / Passive Cooling

• Refrigerant Circuit (R134a): Active Cooling / Cabin AC

• Vehicle Model: Battery load

• Cabin Model

2. Layout & Model Overview

BATTERY

HEATERPASSIVE

RADIATOR

BATTERY

CHILLER

Refrigerant

Side

RESERVOIR

PUMP #1

PUMP #2

COMPRESSOR

CONDENSER

CABIN

EVAPORATOR

BATTERY CHILLER

Coolant Side

IHX

EXV

CABIN

EXV BATTERY

AC CIRCUIT

HEATER VALVEPASSIVE COOLING

VALVE

ACTIVE COOLING

VALVE

CABIN

COOLANT

CIRCUIT


BATTERY

HEATERPASSIVE

RADIATOR

RESERVOIR

PUMP #1

PUMP #2

BATTERY CHILLER

Coolant Side


VALVE

ACTIVE COOLING

VALVE


COOLANT

CIRCUIT

Battery

• Single battery electro-chemical

element to represent the whole battery

pack (Thévenin equivalent circuit)

– 𝑂𝐶𝑉 = 𝑓 𝑆𝑂𝐶, 𝑇

– 𝐼𝑅 = 𝑓 𝑆𝑂𝐶, 𝑇

• Single lumped thermal mass

– Convective + radiative heat to ambient

– Convective heat to coolant

• BEV model used to define the battery

load given a certain vehicle speed:

– P >0: traction power

– P <0: charge power (brake, wall charger)

Electrical loadThermal load to

battery pack

Heat transfer

metal and coolant

Heat transfer to

ambient


COOLANT

CIRCUITBATTERY

HEATERPASSIVE

RADIATOR

RESERVOIR

PUMP #1

PUMP #2

BATTERY CHILLER

Coolant Side


VALVE

ACTIVE COOLING

VALVE


Passive Cooling Branch

• Coolant-Air Radiator

– Predictive modelling approach (master/slave)

– Heat Transfer predicted based on non-

dimensional correlations automatically built

from supplier’s datasheet

– Size scalable for sensitivity analyses

• Air Side

– Ram Duct

• Vehicle velocity imposed at boundaries

• Sensible to ambient conditions

– Electrical Fan

• Map-based modelling

RAM AIR

INLETPASSIVE RADIATOR

Air Side

FAN

RAM AIR

OUTLET

Coolant Side Connection

FAN MOTOR

Air @ Vehicle

Speed



BATTERY

HEATERPASSIVE

RADIATOR

RESERVOIR

PUMP #1

PUMP #2

BATTERY CHILLER

Coolant Side


VALVE

ACTIVE COOLING

VALVECOOLANT

CIRCUIT

Active Cooling Circuit

• Passive Radiator

BATTERY

CHILLER

Refrigerant

Side

COMPRESSOR

CONDENSER

CABIN

EVAPORATOR IHX

EXV CABINEXV BATTERY

AC CIRCUIT

CABIN

Active Cooling Circuit

Cooling source for cabin and battery in

high-temperature ambient conditions

• High Voltage (HV) electric compressor

• Condenser exchanges heat with

external air

• Internal Heat Exchanger (IHX)

– Improve efficiency

– Reduce pressure drop

• Electrical eXpansion Valves (EXV) to

modulate cooling power split between

cabin evaporator and battery chiller

• Validated against target P-h cycle



BATTERY

HEATERPASSIVE

RADIATOR

RESERVOIR

PUMP #1

PUMP #2

BATTERY CHILLER

Coolant Side


VALVE

ACTIVE COOLING

VALVECOOLANT

CIRCUIT

BATTERY

CHILLER

Refrigerant

Side

COMPRESSOR

CONDENSER

CABIN

EVAPORATOR IHX

EXV

CABIN

EXV BATTERY

AC CIRCUIT

CABIN

CABIN

CABIN

EVAPORATOR

(Air Side)

PTC HEATER

EXTERNAL

AMBIENT

AIR BLOWER

Cabin Cooling Circuit

Cabin:

• Single volume (single temp)

• Thermal masses (seats, dash, ...)

• Convective and radiative heat with

external ambient

Air Circuit

• Fixed 50% air recirculation

• Electrical blower

• Evaporator

• PTC Heater


Agenda

1. Introduction



4. Model Setup




3. Control Strategy – Overview

Pumps Speed

Actuation

System State

Active Cooling Controller

Passive Cooling Controller

Heater Controller

PLANT

∆Temperature

Target

Layout

3 main controllers

• State Machine

→ Status determination

• Coolant Flow Demand

→ Battery ∆T

• Cooling Power Demand

→ Compute Cooling or

Heating Need

Component Controllers

• Heater Controller

• Passive Cooling Controller

• Active Cooling Controller

Coolant Flow

Demand

Cooling Power

Demand


3. Control Strategy - Overview

Coolant Flow

Demand

Cooling Power

Demand

Pumps Speed

Actuation

System State



Heater Controller

PLANT

∆Temperature

Target

Layout

3 main controllers

• State Machine



→ Battery ∆T



Heating Need





∆𝑇 𝐵𝑎𝑡𝑡𝑒𝑟𝑦

5°𝐶

𝑃𝑢𝑚𝑝𝑆𝑝𝑒𝑒𝑑

𝐶𝑜𝑜𝑙𝑎𝑛𝑡 𝐹𝑙𝑜𝑤PI

𝑃𝑢𝑚𝑝𝐴𝑐𝑡𝑢𝑎𝑡𝑖𝑜𝑛



Coolant Flow

Demand

Cooling Power

Demand

Pumps Speed

Actuation

System State



Heater Controller

PLANT

∆Temperature

Target

Layout

3 main controllers

• State Machine



→ Battery ∆T



Heating Need





𝑇𝑐𝐵𝑜

𝑇𝐺𝑇

𝐶𝑜𝑜𝑙𝑖𝑛𝑔|𝐻𝑒𝑎𝑡𝑖𝑛𝑔𝑃𝑜𝑤𝑒𝑟 𝐷𝑒𝑚𝑎𝑛𝑑

PI



Coolant Flow

Demand

Cooling Power

Demand

Pumps Speed

Actuation

System State



Heater Controller

PLANT

∆Temperature

Target

Layout

3 main controllers

• State Machine



→ Battery ∆T



Heating Need







Coolant Flow

Demand

Cooling Power

Demand

Pumps Speed

Actuation

System State



Heater Controller

PLANT

∆Temperature

Target

Layout

3 main controllers

• State Machine



→ Battery ∆T



Heating Need






3. Control Strategy – Active Cooling Controller

POWER

DEMAND

SUPERHEAT

CONTROLLER EXV

CONTROLLER

COMPRESSOR &

CONDENSER

CONTROLLER

POWER Demand

Computes a thermal budget based on:• available cooling power

• cooling demand from cabin and battery

• battery cooling is always privileged

COMPRESSOR &

CONDENSER Controller• Compressor speed looked

up on the total cooling

request

• Condenser fan speed is

controlled via a FB+FF

loop on outlet pressure

EXV Controller:Throat area is split

proportionally to the cooling

request on the two valves

SUPERHEAT Controller:PI controller actuating the

equivalent EXV throat area

to control SuperHeat

𝑆𝑢𝑝𝑒𝑟𝐻𝑒𝑎𝑡

𝑇𝐺𝑇PI

𝐶𝑜𝑜𝑙𝑖𝑛𝑔@𝐵𝑎𝑡𝑡𝑒𝑟𝑦

𝑇𝑜𝑡𝑎𝑙𝐶𝑜𝑜𝑙𝑖𝑛𝑔

𝐶𝑜𝑜𝑙𝑖𝑛𝑔@𝐶𝑎𝑏𝑖𝑛

𝑇𝑜𝑡𝑎𝑙𝐶𝑜𝑜𝑙𝑖𝑛𝑔

𝑨𝒓𝒆𝒂𝑬𝑿𝑽𝒃𝒂𝒕𝒕𝒆𝒓𝒚

𝑨𝒓𝒆𝒂𝑬𝑿𝑽𝒄𝒂𝒃𝒊𝒏

𝑻𝒐𝒕𝒂𝒍 𝑬𝒒𝒖𝒊𝒗𝒂𝒍𝒆𝒏𝒕 𝑬𝑿𝑽 𝑨𝒓𝒆𝒂


Agenda

1. Introduction



4. Model Setup





• MiL Approach




placed in the plant modelTo

Actua

tors

From

Sens

ors

CONTROLLER

PLANT

4. Model Setup


4. Model Setup

Battery

Chiller

Evaporator

EXVs

Compressor

Condenser

IHX

Battery packPumps

Heater

LT radiator + fan

Battery

Chiller

2-way valves

Expansion tank

Coolant Flow Demand

Cooling Power Demand

Pumps Speed

Actuation

System State



Heater Controller

∆Temperature

Target

Blower

To A

ctuato

rs

From

Sens

ors

CONTROLLER

PLANT

0.2 - 0.5x

Real Time(Intel i7 3.6GHz)

• Computational Effort

– 700 flow volumes

– Timestep: 0.2s


• MiL Approach




placed in the plant model


Agenda

1. Introduction



4. Model Setup




Steady State Cases (Test Bench Like)

• Worst Cases (Charging – Hot Condition):

– battery recharging in a fast charging station at 100 kW

– external hot ambient air temperature (45 °C)

– passengers asking for cabin cooling

Dynamic Cases (Vehicle Like)

• RTS 95 (~RDE)

– Fully Charged Battery

– Ambient temperature 40°C

– 5 passengers (500 W)



Ambient: 45°C

TotalCoolingCapacity

Mode: Active Cooling

Design Case

Battery HeatRejection

CabinCooling

## [kW] [kW] [kW]

R_45-1 0.5 4 4.5

R_45-2 1 5 6

R_45-3 2 3 5

R_45-4 2 6 8

R_45-5 2.5 4 6.5

R_45-6 3 3 6

R_45-7 3.5 3.5 7

R_45-8 4 4 8

5. Results Assessment - Steady State Cases

Charging – Hot Condition - Results Envelop

• Battery temperature differential below 5°C in all the cases

• Battery chiller to the maximum power to react to high initial battery temperature

• Cabin cooling increased as soon as the battery temperature reaches optimal range

Full Operation Temperature Threshold


5. Results Assessment – Dynamic Case

Ambient: 40°C

TotalCoolingCapacity

Mode: Active Cooling

Design Case

Battery HeatRejection

CabinCooling

## [kW] [kW] [kW]

RTS95 Driving Cycle 5 Passengers -

Driving Cycle – Hot Condition – Case breakdown (RTS95)

• Cabin cooling de-rated for the first 15 minutes

• Cabin temperature at target after 12 minutes

• Battery temperature in optimal range after 8 minutes


Agenda

1. Introduction



4. Model Setup




Conclusions

• An effective BEV thermal management control strategy was

developed before any prototype build and experimental testing.

• Handles the battery cooling and the cabin conditioning in any load

profile and realistic external boundary conditions.

• GT-SUITE proved to be an effective means to model physical systems

and address design choices since the early development phase.

• This approach allows the developer to keep tracking of

performance, safety and comfort at the same time.

Next Steps

• Thermal control strategy will be deployed in a real Electronic Control

Unit (ECU) and used to drive a real system prototype.


THANK YOU FOR YOUR ATTENTION

Any Question?

EUROPEAN GT CONFERENCE 2019

October 7, 2019 - Frankfurt am Main, Germany

POWERTECH ENGINEERING S.R.L.

Via Carolina Invernizio 6, 10127 Torino, IT

www.pwt-eng.com

Giulio Boccardo

+39 011 0709966

[email protected]

Documents

EUROPEAN GT CONFERENCE 2019 - gtisoft.com · European GT Conference 2019 –Frankfurt 2019 G. Boccardo, E. Graziano, L. DeRosa, T. Mrkvica, S. Pautasso –Virtual BEV Thermal Control