CAN based Distributed Real Time Controller implementation for Hybrid Electric Vehicle
Renji V Chacko Scientist E, Power Electronics Group CDAC, Thiruvananthapuram
[email protected]
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Contents 1. Overview of Hybrid Electric Vehicle (HEV) and control requirements 2. CAN in distributed control for HEV 3. CANOpen implementation in HEV control
2
HEV Development Rationale
ICE
Driving cycle
1. Starting and Acceleration
: Peak, transient power from ICE
2. Steady run on level road
: Average, steady power from ICE
3. Deceleration and Stopping
: losses in gear, Brake
“ Efficient power-train control to optimize the performance of ICE for urban city driving cycle”
3
Hybrid Electric Vehicle Control Operate with two power sources Average power (ICE) Transient power (Battery) Parallel HEV ICE Battery Series HEV ICE Battery
Mechanical
Electrical
Mechanical
4
Series HEV Functional blocks Dash Board
~ ICE
= Electric
Electric
=
Generator
~
Motor
= Battery Pack
=
5
Series HEV Bus- M/s Ashok Leyland, Chennai Charger
PMC
GC
CA PM
Battery
Generator
ICE
PMPC
6
Series HEV- 3 Wheeler (M/s KAL, Trivandrum)
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AC Drive Requirements 30
50 45
25
Torque
40 35
20
30 15
25 20
10
15 10
5
5 0
0 0
500
1000
1500
2000
2500
3000
3500
0
1000
2000
3000
4000
5000
6000
7000
Speed Electric ICE
Generator
Battery Pack
~
Electric
= =
~
Motor
= =
8
HEV System Design and Simulation
9
CAN in distributed control for HEV •
Data exchange requirements
10
Control and Communication- eg.Propulsion motor
DC source
Local control
Motor Speed, Torque • (i/p) Motor Current, DC Voltage • (o/p) PWM signals
Communication
INPUT
OUTPUT
Speed reference
Motor speed
Battery/DC voltage
Propulsion Power Demand
Battery SOC
Module status
Start/Stop
Error Indications
Fwd/Rev Emergency Stop
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Data transfer requirements in HEV Parametric Data Exchange Battery Voltage (Vbat) DC link Voltage (Vdc) ICE speed (Nice) Acceleration Pedal reading (Nref) Propulsion motor speed (Npmc) Battery state of charge (Bsoc) Propulsion Controller Power (Ppmc) Generator Power (Pgc) Generator Power reference (Pref) Logical Data Exchange (*) Status of Controllers ICE start command PMC start/stop command BC start/stop command Emergency OFF Forward/Reverse command
Source BC PMC GC DB PMC BC PMC GC DB
Destination DB, GC, PMC DB, BC, GC DB PMC DB DB, PMC DB DB GC
PMC, GC, BC DB DB DB DB DB
DB GC PMC BC PMC, GC, BC PMC
“require Producer – Consumer data exchange”
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HEV Operation Dynamics • • • • •
ICE start up Vehicle Acceleration Steady Cruising Vehicle Deceleration Regenerative Braking Operational Dynamics “require Communication sampling in 10s of mSe”
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Real Time Distributed Control Local control sampling hardware timer
BC
AC d rive
CAN
AC d rive
CAN
Sampling time 200 micro sec
GC
PMC
Time message
Sampling for real time communication across network global time message
Data transfer
DB
Time message
Data transfer
Sampling time 16 milli sec
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CAN in HEV control Application requirements Network capabilities ( real time ) Physical layer suitability ( reliable under EMI) Integration with existing equipment (in vehicle networking) Speed and timing requirements (1mbps) Implementation (availability of components ) Application Layers
Supports distributed real-time control
7
Application
6
Presentation
5
Session
4
Transport
3
Network
2
Data link
1
Physical
Data transport Layers
CAN Protocol
Prioritization of messages through identifiers Non-destructive arbitration for collision resolution Data consistency though error detection and signaling Autonomous switching off of defective nodes Built in acknowledgement
OSI Protocol model S R I Idle O Identifier T D r0 DLC F R E
Data
CAN Frame
CRC
A C EOF K
I F S
Idle 15
Bus Arbitration Process S R I Idle O Identifier T D r0 DLC F R E
Data
CRC
A C K
EOF
I F S
Idle
Multiple transmitters 1. Identify the bus as idle 2. Start Of Frame (SOF) 3. Synchronization of all nodes w.r.t SOF of the node Starting the transmission first 16
Error Handling Error Detection
•Monitoring (transmitters compare the bit levels to be transmitted with the bit levels detected on the bus) •Cyclic Redundancy Check •Bit Stuffing •Message Frame Check
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CANopen (CAN based application Interface) Types of communication objects
Real-time data (Process Data Objects) Configuration parameters (Service Data Objects) Network Management (NMT) Time synchronization (SYNC)
CANOpen services and objects in HEV CAN-Open Objects TxPDO1 TxPDO2 RxPDO1 RxPDO2 NMT SYNC NMT Node Guard Emergency SDO1
Function Slave-Master Periodic transmission (SYNC) Slave- Master RTR transmission Master-Slave Periodic transmission Slave-Slave Periodic transmission State machine control Synchronization of periodic transmissions Check Slave status Error/Abnormal condition Configuration 18
CANOpen State Machine Master
Slave Initialization
Initialization
(Automatic)
(Automatic) Node Gaurd Preoperational After all slave nodes are in preoperational
Operational
Preoperational Reply Start Remote Node PDO
After receiving start remote node
Operational 19
Real time data transmission
20
Real Time Data Distribution in Communication Sampling SYNC
SYNC
RTR
RxPDO1
Master (DB)
TxPDO1
PMC GC BC
TxPDO2
RxPDO2
PMC TxPDO1
TxPDO2
RxPDO2
GC TxPDO1
TxPDO2
RxPDO2
BC Ts 21
Filter configuration for CANOpen S R I Idle O Identifier T D r0 DLC F R E
Data
CRC
Master
10
9
8
7
Function code
6
5
4
3
2
1
0
A C K
CAN bus
EOF
I F S
Idle
Slave
1st Tx PDO Node ID
Rx COBID
2nd Tx PDO Node ID
Rx COBID Node ID
Fun Code Node ID
2nd TxPDO Node ID
Fun Code
Emergency Node ID
0
Node-ID
Structure of the 11-bit identifier
Node ID
Masked Bits
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CAN System Debugging Tx
CPU
CAN module
Loop back
Rx
CAN trans ceiver
CAN_H
CAN_L
CAN software development in Loop Back mode
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Distributed Control of HEV system DB DA
CAN
BC
PMC, GC
“Redundancy and switch over to be addressed” 24
CONFIGURAION
Power ON Initialization of control circuits CAN NMT Services CAN initialization State machine in operational (Master and Slaves) Power circuits De- energized When the vehicle is at stop EV/HEV selection When HEV mode selected Start ICE When EV mode selected Stop ICE, if already ON Forward/Reverse selection Energize Power Circuits
RUN
INITIALIZATION
HEV Operation and CAN messaging
Apply pedal Enable the electric drive Vehicle Run mode
Event triggered PDO
Periodic Data (SYNC PDO) Event triggered PDO (Error handling)
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System Features • Dash board information with no additional meters Vehicle mode (EV/HEV) Battery voltage/Charge Electronic speedometer & Odometer
• Effective Performance evaluation A CAN module in Receiver mode can be plugged to the network and access relevant data Required performance evaluation profile can be implemented in the module
Vehicle speed / Propulsion Motor speed
eg. Acceleration profile 0-14 kmph 13-23 kmph 21-34 kmph 34-50 kmph
….. Sec ….. Sec ….. Sec ….. Sec
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•
CAN based control architecture resulted in reliable HEV proto implementation with satisfactory real time performance.
•
Operational parameters like Max speed, acceleration etc. can be easily configured and controlled for speed governance via ITS interfaces
•
Fleet monitoring and performance evaluation can be effectively implemented using appropriate CAN message data and ITS infrastructure
•
Though Evs and HEVs offer eco friendly public transportation, the economic viability is an issue. Vehicle price Subsidies / Incentives based on performance can promote the implementation.
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Current HEV Developments • Parallel HEV • Mild HEV Electric
ICE
Motor
Battery Pack
=
= =
~
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Parallel HEV Developments
AC drive and battery controller
Linear actuator system for fuel control Propulsion Motor Pedal sensor
Battery Bank
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References • Bates, B. ed., ”Electric and Hybrid Vehicle Technology”, SAE Publication SP-915, February 1992. • BK Powell, KE Bailey, and SR Cikanek, “Dynamic Modelling and Control. of Hybrid Electric Vehicle Powertrain Systems”, IEEE Control Systems, 0272- 1708, October 1998 • Werner Leonhard, “Control of Electric Drives,” Third edition, Springer 2001. • Robert Bosch GmbH, CAN Specification 2.0 Part B • CiA DS 102, CAN Physical Layer for Industrial Applications • CANopen, CAL-based Communication Profile for Industrial Systems, CiA DS-301 • TMS 320C2xx User’s Guide, Texas Instruments Inc. 2000. • PIC 18F44xx User’s Guide, Microchip Inc. 2004. 30
Thank you
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