Technology of Load Management for Enhancement of Power Safety in Vehicles

Transcription

1 EVS28 KINTEX, Korea, May 3-6, 2015 Technology of Load Management for Enhancement of Power Safety in Vehicles Jong-Min Park 1, Cha-Keon Cheong 2 1 Taesung Elecro-Circuit Systems, Republic of Korea, jmpark@tecstar.co.kr 2 Hoseo University, Republic of Korea

2 Introduction I. The major reason of fire in vehicles is the failure of electric system such as damage of electric line, failure of electric contact, and overload, which leads to catastrophic incidents. II. When automobile on 12v Lead Acid battery system collides, Intelligent Battery Disconnecting Systems is required to prevent a fire and to start a car(crank). There are main functions. 1. This is a Power Disconnecting System to cut off the power supply in a collision so that it can prevent electrical fire. 2. To prevent a fire that can be occurred by electric line short in any accident 3. To next cranking a car based on battery SOC(in case of dark current). 4. To support Generation Control Systems by recognizing the battery conditions 2

3 Why need Power Safety System? Vehicle Fire Report ( NEMA( National Emergency Management Agency) Vehicle fire report in Republic Korea from 2007 to 2009 year ) The major reason of fire in vehicles is the failure of electric system reason of electric line short, over current, and crash The electric line are need cut-off system for safety. 3

4 Why need Power Safety System? Damage of Battery Harness by Vehicle Crash Test Engine/Transmiss ion Battery Harness Battery Harness [Crash Test Result] The Battery Harness should be cut after crash The Battery Harness shorted to chassis ground. 4

5 Why need Power Safety System? Can not cranking reason of battery discharge from used black box camera? The Battery system need electric power management for next cranking. We need battery status management as State of Charge, State of Health,.. 5

6 Old Power Safety System Cut-Off Method Crash Detection Short cable Detection Battery Sensing Dark current protection Characteristic Pyro Tech Response time : about 5ms Can not Reuse O X X X 6

7 Summary of Required Function I. Reconstruction of automobile electric systems is needed to disconnect for the effectively power management.(separation Alternator, Starter power and Load power) II. III. The application of Latching relay is needed to secure a reusability and to minimize the dark currents Integrated of high precision sensor(current, voltage, temperature) is using for estimating battery status and measurement of over currents IV. Developments of battery status algorithm via measuring current, voltage, temperature and disconnecting algorithm via measuring over currents V. Power Cut off function 1. The function is to cut off the power by monitoring over currents in crash status. 2. The function is to cut off the power on undercharged battery 7

8 Old Battery System in vehicle Old battery charging system applied to alternator management system(ams) for energy saving and idle stop and go system but the system can not protect of electric line short from crash Load 1 Load 2 Regulated Voltage Battery Status (SoC) Starter Driving Engine Stop Alternator Engine Start Driving 8

9 Developed Power Safety System in vehicle The proposed power safety system integrated battery algorithm to charging control and the system are installed between alternator / starter electric line to battery plus pole. And the system can be cut-off at the event status as short and crash. Black Box emergency Load Signal Interface Cut-Off Load Power System Safety Module Function Old System Developed System Alternator Management Cut-Off Over-Current X Cut-Off Dark Current X 9

10 Required System Configuration 1 Crash Information ACU (Return Switch) 4 (Power Safety System) 2 (Load Management) 3 1 Cut-Off Power system by interface to Airbag ECU 2 Cut-Off Power system from over-current 3 Cut-Off Power system with load management unit for dark current management 4 Battery management from dark current 10

11 System Block Diagram Block Diagram Circuit Diagram 11

12 Current Sensing Result (Hall Effect) The current sensor used 2 channel hall effect solution from Micronas Hal817 and Hal824 because accuracy. Channel 1 sensor used coulomb counting for SoC update and channel 2 sensor are used detection of over current. Current 1 measurement Range : ±130A Current 2 measurement Range : ± 20A Magnetic Collect CORE : Ni alloy [Current Sensors Output Type] [Current Sensors Specification) Test Machine HALT30, Power & loader Test temperature -40, 25,105 Current Sensing Test Result (Current 1 measured error) (Current 2 measured error) 1CH(130A) 2CH(20A) Max. Error (%) 0.45% 0.95% Resolution 80mA 12.2mA Output Range Response Time 0.5V~4.5V Max. 2msec Current sensing error are max. 0.6A 12

13 Voltage Sensing Result The voltage sensor used OCV(open circuit voltage) and the sensing input voltage are directly connected from battery voltage. The voltage are process from analogue digital converter and digital filter in the micro-controller. 16Bit AD Converter Sensor Input A D Filter U- Processor error(v) E OCV Range (0~100%) Voltage(V) Maximum Error SOC(%) Error (Reference : FLUKE 8846A) ±2mV 약 ±0.2~0.3% 13

14 Temperature Sensing Result [Thermistor R-Cuve] B-Constant : 3560K 1 1 R = R 25 Exp B T T 25 The temperature sensor used thermistor sensor(ntc) The sensing result used estimation to battery internal temperature. VDD Measured Dats T[ ] Vout min Vout nom Vout max kω THERMISTOR OUTPUT R = 2.7kΩ + R THERMISTOR VOLTAGE THERMISTOR VDD T25 B log T = B log T 25 ( log R log R )

15 SoC Calculation method Used combination of Methods (Coulomb counting method + Open Circuit System(OCV) method 15

16 SoC temperature compensation and vehicle Test SoC : State of Charge, OCV : Open Circuit Voltage BTM : Battery Temperature Model SOC (%) Developed SOC IBS SOC (sec) BTM ( ) (sec) Developed BTM Battery Inner Temp IBS BTM NTC Temp Temp Error Battery Temperature Calculation : T0-{(T0-T1)*k} Battery temperature compensation SOC=aX+k Test Result are SOC error : ± 4%, BTM error : ±5 16

17 Electric Line Cut-Off Process(Crash and Over current) Normal Status Event Status Detection Cut-Off Return Return Switch Controller Vehicle Load Push MDPS EMS Airconditioner ACU CAN/PWM Turn 릴레이 On Relay 차단 ABS EMS Current > Max. Current Cable Short Battery ALT & Starter 17

18 System Interface for Dark current management Block diagram Fuse Box Block Latch Relay Load B+ Latch Relay Multimedia Load ALT ST Cut-Off Signal M C U Power Switch Lamp Load Body Load Fuse Box EMS SOC/BTM Load CLUSTER Crash Sig ACU Cut-Off Sig Cut-oFF power BAT Cut-Off Unit Request Cut-Off Signal interface The signal are transferred to load management device with PWM signal, if battery SoC status are decreased until to SoC limit 18

19 Electric Line Cut-Off Process(Dark current) Normal Statue Event Detection Cut-Off KEY OFF ON Controller Junction Box SOC < SOC_Limit Estimation SOC Measured Voltage Request Cut-Off Load Management Vehicle Load BCM Battery MTS Erc Unit 19

20 Electric Line Short Test Result 1500A Current Short Shunt Short Cut- Off Cut- Off Unit BAT 20ms 10ms 30ms 4V Relay Current are going to 15,000A relay operating voltage are 4V when the cable are shorted The battery system are disconnected after about 30ms for cable short 20

21 Conclusion This paper described the technology of power shutdown for enhancement of power safety in vehicle. The system could detect the dark current and over-current, and shutdown the power automatically, which result in protection of fire in vehicle in case of collision in addition to enhancement of battery efficiencies. The developed pre-commercialized experimental system was shown stabilized power shutdown operation in the various filed tests. Developed the power safety module are integrated latch relay and sensors(v,i,t) and installed to battery plus pole. Latch Relay Controller CAN Communication Connected to Battery Pole Current Sensors 21

22 THANK YOU! 22