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공학전문석사학위연구보고서
Vehicle Plant Modeling and Simulation to Optimize Mild Hybrid 48V BAS (Belt- driven Alternator Starter) System Controller Algorithm Design
마일드 하이브리드 48V 바스 상위 제어기 최적 설계를 위한 차량 플랜트 모델링과 시뮬레이션
2018 년 02 월
서울대학교 공학전문대학원 응용공학과 이 헌 수
Vehicle Plant Modeling and Simulation to Optimize Mild Hybrid 48V BAS (Belt- driven Alternator Starter) System Controller Algorithm Design
마일드 하이브리드 48V 바스 상위 제어기 최적 설계를 위한 차량 플랜트 모델링과 시뮬레이션
지도교수 차 석 원
이 리포트를 공학전문석사학위 연구보고서로 제출함
2017 년 11월 서울대학교 공학전문대학원 응용공학과 이 헌 수
이헌수의 공학석사 학위논문을 인준함 2017 년 12월 위 원 장 : (인)
위 원 : (인)
위 원 : (인)
Abstract
Vehicle Plant Modeling and Simulation to Optimize Mild Hybrid 48V BAS (Belt-driven Alternator Starter) System Controller Algorithm Design
Hunsoo Lee
Graduate school of Engineering Practice
Seoul National University
It has already been 20 years since Toyota introduced a hybrid vehicle call “Prius”. Many Hybrid vehicles have been produced since then, but even so many years have passed.7 There is still a long way to the popularization of the hybrid vehicle. It is still very low compared to the total number of vehicles.
Why? That is probably due to the cost of the Hybrid system being added.21 Even though Hybrid vehicles are eco-friendly and high fuel efficiency, the cost of producing the vehicle is too high compared to the benefits to the customer.18 The cost is about $5,000 which is too much. The very cost was a problem which is stumbling block to i
popularization.
To solve this problem, 48V BAS (Belt-driven alternator starter) hybrid system is proposed. This is the Mild Hybrid compared to the
Toyota Prius. This system can design the entire hybrid system at about $800.20
The problem in research and development organization of our company is that it is difficult to understand the development contents because we outsourced the various modeling to universities and professional developers. In order to solve this problem, we set it as a GSEP project.
The basic model was based on the EV (electric car) model that was previously performed in our company. And then the necessary parts from the 48V BAS have been added. The main point of this project is the vehicle modeling that is the target of the high level controller –EDU. Generation of the input variable (output variable) which required for high level controller was simulated.
Keyword: Mild Hybrid, 48V, BAS, Modeling, Simulation. Student Number: 2016-22251
ii
Contents
Abstract...... i Contents...... iii
List of Tables…………………………………...………………………v List of Figures………………………………….………………….…. vi
Chapter 1. Introduction………………………...……………….…….1
1.1 Study Background…………………………………………………….1 1.1.1 Needs for EV…………………………………...... …...... …. `1 1.1.2 Why especially 48V Mild Hybrid EV…………….….….2 1.1.3 Mild Hybrid Technology trend…….………………………3 1.2 Purpose of This Project………………….…………….…….….….6
Chapter 2. System Configuration……………………………………7
2.1 Mild Hybrid 48V BAS Architecture……………………….……7
2.2 48V Power Network…………………………………………….…8
2.3 Vehicle and EDU Modeling………………………………….……9
2.4 Configuration of HILS and RCP17……………………….……….10
2.5 Configuration of the interface between the Controller…….11
Chapter 3. Vehicle System Modeling …………………………….13 3.1 Input & Output Variable…………………………………….…13
iii
3.2 Vehicle Modeling……………………………………………….18
3.2.1 Plant: EV (Electric vehicle) Model Analysis...... 18
3.2.2 Plant_CAN: MEV Block……………………...………….20
3.2.3 Combination of MEV Block and Autonomie Model….21
3.2.4 Battery(ESS) function update………………………….24
3.2.5 Dynamics (Wheel + Chassis) function update…….26
3.2.6 CAN communication set up…………………………….28
3.3 EDU Logic Modeling……………………………………….….30
Chapter 4. The Result for Simulation……………………...…...32
4.1. Simulation based on driving cycle……………………………32
4.1.1. Analysis result of UDDS driving cycle…………………...32
4.1.2. Analysis result of NEDC driving cycle………….……….35
4.1.3. Analysis result of WLTC running cycle………………….38
4.2. Actual vehicle verification……………………………………….42
Chapter 5. Conclusion……………………………………………….44
Bibliography………….…………………………………………………45 국문 초록…..…………..………………………………………………..50
iv
List of Tables
Table 3.1 Input Variable from ECM……………………………………...... 13
Table 3.2 Input Variable from BMS……………………………………...... 14
Table 3.3 Input Variable from INVERTER……...…………………...... 15
Table 3.4 Input Variable from LDC……...……….…………………...... 16
Table 3.5 Output Variable from EDU……….…….…………………...... 17
Table 3.6 Wheel and Chassis Dynamic function update……...... 27
Table 3.7 CAN Specification ………………....…….…………………...... 28
Table 3.8 CAN Definition for Engine state....….…………………...... 29
Table 4.1 Fuel Economy comparison of 48V BAS vs Conventional type at UDDS………………………………………………….……………….32
Table 4.2 Fuel Economy comparison of 48V BAS vs Conventional type at NEDC……………………………………………………,.…….…...... 35
Table 4.3 Fuel Economy comparison of 48V BAS vs Conventional type at WLTC ……………...... 38
v
List of Figures
Figure 1.1 Global New Powertrain System requirement...... 1
Figure 1.2 HEV Function & Classification...... 3
Figure 1.3 VCU (Vehicle Control Unit) and Vehicle Modeling...... 5
Figure 2.1 Mild Hybrid BAS 48V Architecture7...... 7
Figure 2.2 48V Power Network16………………………...... 8
Figure 2.3 Vehicle Modeling Concept ...... ………………...... 9
Figure 2.4 Configuration of HLS and RCP tool...... 11
Figure 2.5 Interface between the controller...…………...... 12
Figure 3.1 Electric Vehicle Model Overview...…………...... 19
Figure 3.2 MEV Bock modification...…………...... 20
Figure 3.3 Combination of MEV Block and Component Model...... 22
Figure 3.4 Vehicle and subsystem structure...... 23
Figure 3.5 Battery(ESS) function update before and after...... 25
Figure 3.6 48V BAS Key mode...... 30
Figure 3.6 EDU logic function structure...... 31
Figure 4.1 UDDS (Urban Dynamometer Driving Schedule………...... 33
Figure 4.2 Engine and Motor Operating Point at UDDS…………...... 34
vi
Figure 4.3 NEDC (New European Driving Cycle) …………………...... 36
Figure 4.4 Engine and Motor Operating Point at NEDC…………...... 37
Figure 4.5 WLTC (Worldwide Light vehicle Test Cycle) ………...... 39
Figure 4.6 Engine and Motor Operating Point at WLTC…………...... 40
Figure 4.7 48V BAS Vehicle (Front)…………………………………...... 41
Figure 4.8 HILS Installation…………………………………………...... 42
Figure 4.9 DC/DC Converter Installation………………………...…...... 42
Figure 4.10 BAS (Belt driven alternator starter Installation…………43
Figure 4.11 48V Battery Installation……………………………………...43
vii
Chapter 1. Introduction
1.1. Study Background
1.1.1 Needs for EV As the environment of the automobile industry changes rapidly, the demand for a new type of vehicle powertrain has been increased. Especially a solution for the exhaust gas regulation, global warming, and energy problem in each country was needed.
To satisfy these demands, EV (Electric Vehicle), FCEV (Fuel
Cell Electric Vehicle) and HEV (Hybrid Electric Vehicle) have emerged.3
Figure 1.1 Global New Powertrain System requirement21
１
1.1.2 Why especially 48V Mild Hybrid EV?
In the case of the Full HEV (Hybrid Electric Vehicle) which was launched with the Toyota Prius, the vehicle price was very high, since the system configuration cost was very high. This was a fatal weakness for the growth of EV vehicles. Since its debut in 1997, It has not been popularized for nearly 20 years due to its high price. On the other hand, for Micro HEVs the effect was insufficient compared to rising costs for the system due to low efficiency.6,18
However, the 48V Mild Hybrid BAS, which we are planning to develop, will cost about $800 for the system configuration.20 And fuel economy improvement can be expected up to 15%.1 It is the most cost-effective system available.
２
Figure 1.2 HEV Function & Classification21
1.1.3 Mild Hybrid Technology Trend
As the safety and convenience specifications of vehicles have recently been expanded and the demand for high-power / high- efficiency systems for exhaust gas regulation has increased, existing systems have been replaced by electric motors and electronic control devices.2,4,16 The EU passed a regulation to reduce carbon dioxide emissions by 27% from 130g / km in 2015 to
95g / km in 2021 in February 2014.15 Currently, the generation capacity of general passenger cars is about 1.2 [KW] ~ 1.5 [KW].
３
However, since 2015 the demand for power generation capacity required by automobiles increased from 3.0 [KW] ~ 7.0 [KW].
Research has been actively conducted on a 12 V and 48 V dual voltage power system that is capable of using a high voltage load and is highly compatible with a conventional 12 V power system.16
European automakers will be mass-produced in sooner or later by applying BAS (Belt-driven Alternator Starter) based on a 48 [V] power system through collaboration with related parts companies.21
In order to cope with exhaust gas and fuel efficiency regulations such as Euro6, demand for electric equipment based on 48 [V] power supply is increasing.18
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1.2 Purpose of This Project
The purpose of this project is to integrate BAS E-Machine and
Inverter, two-way DC-DC converter and 48-V lithium-ion battery, which are core components of an automotive 48 [V] power system to improve fuel efficiency and efficiency of the automobile.18,16
Figure 1.3 VCU (Vehicle Control Unit) and Vehicle Modeling
Project Scope was Mild Hybrid 48V BAS System Development. Sub-
Project was set as Mild Hybrid 48V BAS VCU design program.20 To design the optimized controller (VCU), BAS vehicle was modeled and simulated.11,22,23
Project technical requirements was Modeling technology of vehicle
５
system using MATLAB, SIMULINK.10
Project development of VCU Controller side created the appropriate software logic configuration for the vehicle control unit(VCU) Using
MATLAB and SIMULINK.3
Purpose of project development of Vehicle modeling side was
. To populate modeling of the entire vehicle system
using MATLAB and SIMULINK
. To simulate the entire system through this work
. To control various variables of the other system which
is connected with BAS
. To implement Modeling, which is close to the actual
vehicle
. To check response to changes of EDU logic
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Chapter 2. System Configuration
2.1 Mild Hybrid BAS 48 V Architecture
Figure 2.1 Mild Hybrid BAS 48V Architecture20
The architecture of this system is configured as described above.
The EDU, which controls the entire vehicle, is a key part of the 48V
BAS.8 The system consists of INVERTER which is the controller of
E-machine, DC / DC Converter which controls 48V and 12V Power,
ECM to control the engine, and ABS to control chassis.13,21
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2.2 48V Power Network
Figure 2.2 48V Power Network16
In case of the 48V power supply, it is located on the rear side of the vehicle, and BAS is installed in the engine part, and INVERTER, which is a control E-machine, is disposed beside it.
８
2.3. Vehicle & EDU Modeling
The model was modified to 48V BAS by using the MEV (Mini
Electric Vehicle) model which was made in the past program as a base model. For this purpose, the MEV model was analyzed. The
48V BAS EDU (Electrical Development Unit) was also configured by existing electric vehicle MEV VCU(Vehicle Control Unit) as a base model.13
Figure 2.3 Vehicle Modeling Concept
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2.4. Configuring HILS and RCP
For this, HILS (Vehicle Target) is used for the vehicle model and RCP (EDU Target) for the host controller.17 Modeling was done using the Simulink tool after connecting Notebook PC as Host on top of these two modules. Simulink can only be connected itself on the computer, but the reason for connecting each of these targets such
HILS and RCP is to create a vehicle test environment similar to the actual hardware so that we can prepare for future problems in advance.
RCP (EDU Target) is a function of Micom in actual hardware.
Later, when the actual vehicle is built, It actually can run the vehicle with connecting to IO Board
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Figure 2.4 Configuration of HLS and RCP tool
2.5 Configuring the interface between the controllers
BAS (Belt-driven Alternator Starter) system consists of
EDU, BMS, INVERTER, ECM, DC / DC converter. Each of these elements communicates closely with each other and perform their respective roles in the entire vehicle system. The EDU controls the whole systems between these components.13
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Figure 2.5 Interface between the controller
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Chapter 3. Vehicle System Modeling
3.1 Define Input and Output Variable
In order to do modeling, it is needed to define a variable that enters and exits each system.21 Each system is divided into ECM,
BMS, INVERTER, LDC, and EDU, and the parameters are defined under each condition.
Table3.1 Input Variable from ECM
Data Instrument Name Description Unit Range
VKPH Vehicle Speed kph 255 Accel pedal status VCLSTHRT Boolean 0,1 1=accel pedal is depressed, 0==accel pedal is not depressed 0: LDCtroller Reset 1: Ignition Key is On, Engine not Turning 2: Ignition Key is On and Engine is Turning at Cranking Speed ENGSTATE 3: Ignition Key is On and Engine is Turning at Running Speed Enum 1~7 4: Ignition Key is On and Engine has ceased Turning 5: Ignition Key is Off and ECM is in Power Off Delay Process 6: Ignition Key is Off and ECM is in Process of Shutting Down
EPEDPOSN Accel Pedal Position pct 0~200 APS_AI
IGNSTATE Ignition State Boolean 0,1 IGN_Input_DI 1=Vehicle key is at ignition position, 0=Vehicle key is not at ignition position
ACDASH Reflects status of the A/C request switch on the vehicle dash Boolean 0,1 A/C Request_DI 1=ACDASH is on, 0=ACDASH is off
EBRAKE Brake pedal status Boolean 0,1 EBrake_SW_DI 1=brake pedal is depressed, 0==brake pedal is not depressed
SMTTURNON Cranking signal Boolean 0,1 CRANK_EN_DI 1=Cranking is activated, 0=Cranking is not activated Gear State VTGEAR Boolean 0,1 0=neutral gear, 1≠neutral gear VCOOLTMP Engine Coolant Temperature ˚C -256~256
CLUTCH CLUTCH state Boolean 0,1 CLUTCH_DI 1=Clutch pedal is depressed, 0=Clutch pedal is not depressed
ISGMNSWON ISG Manual Switch Boolean 0,1 ISG_DIS_DI 1=ISG stop function is used, 0=ISG stop function is not used
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Table 3.2. Input Variable from BMS
Data Instrument Name Description Unit Range PACK_VOLT mV of 48V battery from BMS mV 0~65535 BAT48SOC SOC of 48V battery from BMS percent 0~6553.5 BAT48CUR Current of 48V battery from BMS amp -1~1 BMS_READY BMS is ready for operation Boolean 0,1 BMS_FF BMS fault occurs Boolean 0,1 ERR_FAN 1 : FAN diagnostic error Boolean 0,1 ERR_RAM 1 : RAM diagnostic error Boolean 0,1 ERR_ROM 1 : ROM diagnostic error Boolean 0,1 ERR_TEMP_SENS 1 : Temperature Sensor diagnostic error Boolean 0,1 ERR_CURR_SENS 1 : Current Sensor diagnostic error Boolean 0,1 ERR_MAIN_RLY 1 : Main Relay diagnostic error Boolean 0,1 ERR_PRE_RLY 1 : Pre-charge Relay diagnostic error Boolean 0,1 ERR_EXT_EEP 1 : Ext. EEPROM diagnostic error Boolean 0,1 ERR_AFEIC 1 : AFEIC diagnostic error Boolean 0,1 CHG_OCP 1 : Over charge protection current Boolean 0,1 DCG_OCP 1 : Over discahrge protection current Boolean 0,1 IS_CURR 1 : Abnormal current (When the relay is turned off) Boolean 0,1 CHG_OVP 1 : Over charge protection voltage Boolean 0,1 DCG_UVP 1 : Over discharge protection voltage Boolean 0,1 UVP_SHDN 1 : Over discharge shutdown voltage Boolean 0,1 CELL_OTP 1 : Over temperature protection Boolean 0,1 CELL_UTP 1 : Under temperature protection Boolean 0,1 CB_ON BMS status information Boolean 0,1 FAN_STATUS BMS status information Boolean 0,1 WARN_STATUS BMS status information Boolean 0,1 PRTC_STATUS BMS status information Boolean 0,1 ERR_STATUS BMS status information Boolean 0,1 12V_STATUS BMS status information Boolean 0,1 PRE_C_RLY_ON RELAY status information Boolean 0,1 MAIN_RLY_ON RELAY status information Boolean 0,1
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Table 3.3 Input Variable from INVERTER
Data Instrument Name Description Unit Range VRPM Engine Speed (LSB) rpm 0~8200
INV_READY Inverter is ready for operation Boolean 0,1
DERATEINV Derated torque is requested from Inverter to EDU Boolean 0,1
INV_FF Inveter fault occurs Boolean 0,1
W_Overheat Warning,Overheat Boolean 0,1
W_Stall Warning, Rotor Stall Boolean 0,1
W_LoadDump Load Dump Boolean 0,1
W_LowVoltage Low Voltage Boolean 0,1
Flt_BeltSlip Fault, Belt Slip Boolean 0,1
Flt_Brush Fault, Brush Wearing Boolean 0,1
Flt_Bridge Fault, Bridge Fault Boolean 0,1
Flt_SWinding Fault, Stator Winding Boolean 0,1
Flt_RWinding Fault, Rotor Winding Boolean 0,1
Flt_SISensor Fault, Stator Current Sensor Boolean 0,1
Flt_RISensor Fault, Rotor Current Sensor Boolean 0,1
Flt_PSensor Fault, Position Sensor Boolean 0,1
Flt_TmpSensor Fault, Temp Sensor Boolean 0,1
Flt_VSensor Fault, Voltage Sensor Boolean 0,1
Flt_Memory Fault, Memory Boolean 0,1
Flt_Watchdog Fault, Watchdog Boolean 0,1
Flt_FirstCrank Fault, First Cranking Boolean 0,1
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Table 3.4. Input Variable from LDC
Data Instrument Name Description Unit Range
LDC_READY LDC is ready for operation Boolean 0,1
LDC_WF Warning No Warning Boolean 0,1
LDC_FF FaultNo Fault Boolean 0,1
CAN_CONN_ ERR If there is no more than 5 seconds of CAN receive data Fault Boolean 0,1 [Clear by HCU command] CAN_VAL_ERR Boolean 0,1 -1.2 <= Pref <= 3kW Error at time [Ignition Off->On Clear] LCD_HW_FF Boolean 0,1 H / W LS OV or LS OC Fault when sensed [Clear by self clear / HCU command] HSV_OVF Boolean 0,1 Fault when HSV> 54V Fault when HSV < 24V HSV_UVF Boolean 0,1 Recovery when HSV > 36V [Clear by self clear / HCU command] LSV_OVF Boolean 0,1 Fault when LSV > 18V BUCK Enable CMD On인 경우 LSV < 6.5V 일 시 Fault LSV_UVF Boolean 0,1 BOOST Enable CMD On인 경우 LSV < 9V 일 시 Fault [HCU 지령에 의해 Clear] HSC_OCF Boolean 0,1 BOOST Enable CMD On인 경우 HSC > 25A 일 시 Fault [Clear by HCU command] LSC_OCF Boolean 0,1 LSC > 230A 일 시 Fault LDC Temp > 85℃ 일 시 Fault LDC_OTF Boolean 0,1 LDC Temp < 65℃ 일 시 Recovery [Clear by HCU command] PWM_ERR_F Boolean 0,1 PWM Error 일 시 Fault HSV > 52V 일 시 Warning HSV_OVW Boolean 0,1 HSV < 52V 일 시 Recovery HSV < 36V 일 시 Warning HSV_UVW Boolean 0,1 HSV > 36V 일 시 Recovery LSV > 16V 일 시 Warning LSV_OVW Boolean 0,1 LSV < 16V 일 시 Recovery LSV < 10V 일 시 Warning LSV_UVW Boolean 0,1 LSV > 10V 일 시 Recovery LSC > 218A 일 시 Warning LSC_OCW Boolean 0,1 LSC < 218A 일 시 Recovery LDC Temp > 65℃ 일 시 Warning LDC_OTW Boolean 0,1 LDC Temp < 65℃ 일 시 Recovery BAT12VOL Voltage of 12V battery from LDC volt 0~25
BAT12CUR Current of 12V battery from LDC current 0~25
˚C LDC_TEM -40~150
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Table 3.5 Output Variable from EDU
Data Instrument Name Description Unit Range FCRBAT4812R ISG First crank from both 48V & 12V battery is requested to LDC Boolean 0,1 FCRBAT48R ISG First crank from only 48V battery is requested to LDC Boolean 0,1 FCRREQSTD ISG First crank motoring is requested to Inverter Boolean 0,1 STPREQSTD ISG stop is requested to Inverter Boolean 0,1 CRABAT4812R ISG Crank from both 48V & 12V battery is requested to LDC Boolean 0,1 CRABAT48R ISG crank from only 48V battery is requested to LDC Boolean 0,1 CRAREQSTD ISG Crank motoring is requested to Inverter Boolean 0,1 GENREQSTD Generation mode is requested to Inverter Boolean 0,1 GEN12VCHA Charge of 12V Battery is requested to LDC Boolean 0,1 GEN48VCHA Charge of 48V Battery is requested to LDC Boolean 0,1 TQAREQSTD Torque assist is requested to Inverter Boolean 0,1 REGREQSTD Regeneration is requested to Inverter Boolean 0,1 REG12VCHA Charge of 12V Battery is requested to LDC Boolean 0,1 REG48VCHA Charge of 48V Battery is requested to LDC Boolean 0,1 Requested Mode from EDU to Inverter
0: SYSINITEN is requested 1: SYSREADEN is requested 2: SYSKEOFEN is requested 3: FCRREQSTD is requested MODREQSTD 4: GENREQSTD is requested Enum 0~9 5: STPREQSTD is requested 6: CRAREQSTD is requested 7: REGREQSTD is requested 8: TQAREQSTD is requested 9: Free Wheeling is requested 10: Free Wheeling is requested due to Malfunction Free wheeling mode is activated FREEWHEEL Enum 0,1 1=Free wheeling mode is activated, 0=Free wheeling mode is not
TORQFINAL Final torque to Inverter Nm -200~200
PWR_LMT Power limit requested from EDU to LDC Watt -1200~3000 0: 'Power Off' is requested to INV & LDC SYSRELYON Boolean 0,1
0: 'Relay Off' is requested to BMS RLY_ON Boolean 0,1 1: 'Relay On' is requested to BMS 0: 'Power Off' is requested to INV & LDC SYSRELYON Boolean 0,1
１７
3.2 Vehicle Modeling
3.2.1. EV (electric vehicle) Model Analysis: Plant CAN file
It is a straight running simulation model with only the target speed, so additional model such as power steering, lateral acceleration or speed is not required.5,23 Autonomie's model was modified and added to the current EV (Electric Vehicle) model.
Other files within the entire folder are considered files for VCU and CAN communication. The vehicle model was created by modifying this Plant file. The EDU part has been modeled separately. The initial vehicle model was populated. This model is an Electric Vehicle and it is a Forward Simulator type model in which the Driver Model follows the target speed through the PID control and transfer function by setting the target speed as a profile in each mode.
１８
Figure 3.1 Electric Vehicle Model Overview
１９
3.2.2. MEV Block
Analog_interface and Digital_In_From_VCU are blocks that support the vehicle model (VCU, etc.).
Only the MEV Block was analyzed in detail and then 48V BAS vehicle model was created.
In order to make this model as 48V BAS hybrid vehicle, at least the battery, ChsAPS1, ChsAPS2, ChsBrk, Cruise Control SW, Mot, and
Veh have been modified.7
Figure 3.2 MEV Bock modification
２０
3.2.3. Combination of MEV Block and Component Model
An Autonomie Block has been added to the MEV (Mini Electric
Vehicle) Block. The unused variables and signals in the variable block of the hybrid vehicle model were cleaned up constantly. The ESS
(Electric Storage System) is combined with the battery of the existing EV (Electric Vehicle) model.21 Starter and engine which did not exist in the electric car model were added and combined.
The parameters in each block are summarized. Engine, Clutch,
Gearbox, Final Differential, and Mechanic acc. were newly added models, so the signal output is summarized. Driver Model and Vehicle
Power Control were combined with EDU (Electric Development Unit) developers. ESS, Wheel, Chassis, Motor, Power Converter, and
Electric Acc. have been combined with existing models.16
Starter modeling was included in the Engine model. And the Final
Differential model was included in the Gearbox model. The Power
Converter model was included in the Electric Accessory model. Other signals have been processed.
２１
Figure 3.3 Combination of MEV Block and Component Model
２２
Figure 3.4 Vehicle and subsystem structure
２３
3.2.4. Battery(ESS) function update
ESS (Energy storage system) model was based on EV
(Electric Vehicle) model because the battery (ESS) model in existing
EV models such as CAN communication was bigger and more complicated.21 The Plant Block segment was not used in the
Autonomie Model being added. However only Control part was mainly used and the input and output were modified. ESS (Energy Storage
System) was collected from the output.
Autonomy block was combined with existing battery. The use of the existing current and voltage generation, command (power max, min), used an Autonomie block.
Since the efficiency was used in the existing motor block, the required current entered the battery. A power converter (electric accessory load) and a starter load were connected to that load. And it was connected to Battery.16
２４
Figure 3.5 Battery(ESS) function update before and after
２５
3.2.5. Dynamics (Wheel+Chassis) function update
VCU and Embedded System related parameters have been reported.
After the CAN data was acquired, the model signal was converted.
Dynamics of the EV model functions like the sum of Autonomie's
Wheel and Chassis blocks.9 Because there were many variables, it was divided into types such as Input, In block parameter, and Output.
Block was more complex. So, Autonomy was basic and EV was added.
２６
Table3.6 Wheel and Chassis Dynamic function update9
２７
3.2.6. CAN communication Set up
Embedded System parameters which were related to EDU and BMS,
Inverter etc. were received.21 After CAN database was recognized, the signals of each system modeling have been converted.
Table3.7 CAN Specification
Protocol CAN 2.0B Message format Standard (11 bit identifier) Baudrate 500 kbps
Doc Contents EDU-ECU, ReadDataByPacketIdentifier Service ID Delete Engin Add RPM, Vehicle Speed, Engine Coolant Temperatureat 48V BAS CAN DB_r4 ReadDataByIdentifier Request Service ID Error fix RESPONSE to the message, Tester Present BMS Message ID Revision (Refer to 0x6XX -> 0x2XX, Sheet 'BMS')
２８
Table3.8 CAN Definition for Engine state
ENGSTATE REQEUST the signal, ENGSTATE0xD0000574 Message Period START START Length ID (HEX) Source Signal Name Description Name [msec] Byte Bit (bit) 0 0 8 Req_Length 0x07 Req_Service_ID 0x23 1 8 16 Memory Address MSB 0xD0 3 24 8 Memory Address Midldle MSB 0x00 0x7e0 Req_ECUdata EDU 4 32 8 Memory Address Middle LSB 0x05 5 40 8 Memory Address LSB 0x74 6 48 8 Memory Size MSB 0x00 7 56 8 Memory Size LSB 0x02
RESPONSE to the request, 0xD0000574ENGSTATE Message Period START START Length ID (HEX) Source Signal Name Description Name [msec] Byte Bit (bit) 0 0 8 Req_Length 0x07 Req_Service_ID 0x63 1 8 16 Memory Address MSB 0xD0 3 24 8 Memory Address Midldle MSB 0x00 0x7e8 Res_ECUdata ECU 4 32 8 Memory Address Middle LSB 0x05 5 40 8 Memory Address LSB 0x74
6 48 8 Memory Size MSB 0x00
7 56 8 Memory Size LSB 0x02
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3.3. EDU Logic Modeling
The EDU Logic function model was created based on the vehicle model.3 There are various modes for driving the 48V BAS vehicle.
The core modes are 4 modes as follows. First of all, there is
Cranking mode which is used to start the vehicle. And it is divided into 1st cranking and Normal warmed up cranking. Next key mode is
Generating which is responsible for Charging the vehicle battery. And
Torque boosting,10 which plays an important role as a motor in the
Hybrid. And then, there is regenerative braking, which plays a very important role in improving the fuel economy of hybrid vehicles.1
Figure 3. 6. 48V BAS Key mode
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Figure 3.6. EDU logic function structure
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Chapter 4. Result for Simulation
4.1. Simulation based on driving cycle
4.1.1. Analysis result of UDDS driving cycle
In order to verify the vehicle model and EDU model, were conducted various driving modes were conducted. The test mode shown below is the UDDS mode, which means the Urban
Dynamometer Driving Schedule. This mode was established by shaping North American people's driving mode. While driving in each test mode.24 actual vehicle speed follows the target speed correctly.
When driving in this mode, the fuel consumption was improved by 12.21% as shown in table 4.1 as below. This is the result compared with the conventional type vehicle. In addition to this, the
HC decreased by -11.66%, the CO decreased by -26.41%, and the
NOx decreased by -11.15%.
Table 4.1 48V BAS vs Conventional type at UDDS
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Figure 4.1 UDDS (Urban Dynamometer Driving Schedule)
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Figure 4.2 Engine and Motor Operating Point at UDDS
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4.1.2. Analysis result of NEDC driving cycle
The vehicle model and the EDU model were also verified in NEDC
(New European Driving Cycle) mode. In this mode, Actual Speed followed the target speed too. In this mode, the fuel consumption was improved by 9.10% compared with the conventional type.
This result is somewhat lower than that of the UDDS mode with
12.21% improvement.
The fact that fuel economy did not improve much compared to
UDDS seems to be due to a large number of ECE mode.1 ECE mode is city traffic mode. As shown in Table 4.2 below, HC decreased by
-10.83%, CO decreased by -8.49%, and NOx decreased by -
18.07%.
Table 4.2 48V BAS vs Conventional type at NEDC
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Figure 4.3 NEDC (New European Driving Cycle)
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Figure 4.2 Engine and Motor Operating Point at NEDC
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4.1.3. Analysis result of WLTC running cycle
The vehicle model and the EDU model was verified in WLTC
(Worldwide Light Vehicle Test Cycle) mode. This mode is a test mode that reflects actual road conditions since the Volkswagen emission cheating issue. In the case of existing UDDS or NEDC, the mode was optimized for the LAB, but WLTC was established to reflect real-world driving.11-13
In this mode, Actual Speed also followed the target speed. In this mode, the fuel efficiency was 3.10% higher than the conventional type.18 This result is much less than other modes. In the case of
BAS, regenerative braking plays a big role in improving fuel efficiency. However, WLTC mode reflects a lot of actual road conditions. In emission cycle mode, a stable decel was not achieved.14
Table 4.3 48V BAS vs Conventional type at WLTC
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Figure 4.5 WLTC(Worldwide Light vehicle Test Cycle)
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Figure 4.6 Engine and Motor Operating Point at WLTC
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4.2. Actual vehicle verification
Actual vehicle was built to verify that the logic created in the
computer and HILS state works well in the vehicle condition. EDU
Algorithm has been created over 80% before the actual vehicle was
built. Generally, it is about 60%. Program lead time has been
shortened by almost 6 months. The function was working well not
only on computer simulation but also hardware on the actual vehicle
using HILS and R.P. Tool.23
Figure 4.7 48V BAS Vehicle(Front)
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Figure 4.8 HILS Installation
Figure 4.9 DC/DC Converter Installation
４２
Figure 4.10 BAS(Belt-driven alternator starter) Installation
Figure 4.11 48V Battery Installation
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Chapter 5. Conclusion
In this study, new BAS Control strategy and the logic algorithm have been proposed. It was confirmed that logic which was created by modeling works appropriately on actual build vehicle. In simulation condition, the new 48V BAS System showed 12.21% fuel efficiency increase in UDDS compared to the conventional type vehicle. In the case of exhaust gas HC: 11.66%, CO: 26.41% and
NOx: 11.15% were decreased. This is due to charging gain in
Regenerative Braking in a deceleration condition. The engine has been driven at the optimum point, helped by the use of the motor where the efficiency of the engine is low.
However, this result is somewhat lower than the initially expected
15% improvement. This is probably due to the low maturity of
EDU Logic. And able to reach initial target when additional logic upgrades are made.
Further Logic upgrades will be made at the actual vehicle condition.
Actual vehicle data and simulation data will be compared with each other.
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Bibliography
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국 문 초 록
Toyota에 의해 Prius라는 Hybrid 차량이 소개된 지도 벌써20년이
넘어간다. 하지만 그동안 많은 Hybrid 차량들이 생산 되었지만 그렇
게 많은 세월이 흘렀음에도 불구하고 아직도 대중화의 길은 멀다. 여전
히 전체 차량에 비하면 미미한 수준이다. 왜 그럴까, 그건 바로 가격의
문제일 것이다. 물론 Hybrid 차량이 친환경적이며 연비도 좋지만, 그 얻
는 효용에 비하여 차량 생산 비용이 너무 비싸다. 그 비용은 대략
$5,000 정도 되며 이는 너무 크다. 바로 그 가격이 문제 이었던 것이다.
이를 해결 하기 위하여 본 논문에서 48V Hybrid system을 제안하고
자 한다. 이것은 Toyota Prius등에 비하면 Mild Hybrid 에 해당된다.
이 System은 대략 $800 정도에서 전체 Hybrid System을 꾸밀 수 있
다. 이를 통해 가장 비용 대비 높은 효율의 System을 구현하여 Hybrid
System이 대중화 될 수 있는데 일익을 담당하고자 한다.
또한 지금까지의 연구 개발에 있어 또다른 문제점은 각종 Modeling
에 대해 전문 개발 업체에 외주를 줌으로써 그 개발 내용 자체 파악이
어려웠다는 점이다. 이를 해결하기 위해 48V BAS System 이라는 큰
프로젝트 아래 Modeling을 세부 프로젝트로 설정하여 직접 진행하였고
이를 통해 관련 기술을 내재화 할 수 있었다.
기본 Model은 기존에 수행하였던 EV(전기차) model을 Base로 하여
５０
여기에 48V BAS에서 필요한 부분을 추가하는 방식으로 진행 하였다.
이 Project의 핵심은 상위제어기의 대상이 되는 차량이므로 상위제어기
에 필요한 Input variable(차량 모델 기준 output variable) 을 생성해
내어 Modeling 하였다. 또한 EDU를 각각의 모드에 대하여 modeling
하여 차량이 구동 될 수 있도록 하였다.
완성된 차량 Model과 상위 제어 EDU Model로 Simulation 을 수행
해본 결과 Conventional Type vehicle 대비 12%의 연비 향상이 있음을
확인할 수 있었다. 또한 이를 통해 생성된 상위 제어 Logic으로 실 차량
에서 성공적으로 구동이 됨을 확인되었다.
주요어: 마일드 하이브리드, 48볼트 바스, 모델링, 시뮬레이션 학번: 2016-22251
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