Senior Design Team 2008 UCEM Power Train Sponsor: UConn Electric Motorsports Club Team: Zachary Ahearn, Waleed Hussain, Dennis Basar, Spencer Arnold Advisor: Sung-Yeul Park
Our Sponsor The UConn Electric Motorsports Team (UCEM) is a student-run, professional organization ● that designs and builds an electric, open-wheeled formula style race car Currently still in the designing and fabrication stage of “The Prometheus” ●
Project Statement Our team has three main objectives: ● Evaluating the performance of a preselected motor and battery system, both individually and as a completed, ○ integrated system Developing an embedded system to display real-time information about the power train ○ Assisting the ME senior design team on integrating a cooling system for the full power train ○ Each team member will be responsible for heading one of four subsystems: ● Battery Management System (BMS) → Dennis Basar ○ Battery and Battery Charger → Waleed Hussain ○ Motor and Motor Drive → Spencer Arnold ○ Embedded System → Zachary Ahearn ○ Our designs must adhere to Formula SAE rules and regulations ●
Before We Begin Information Acquisition ● A majority of the first semester will be devoted to researching and understanding the ○ choices of the previous years Senior Design teams Safety Concern and Mitigation ● High Voltage Training ○ Electric Safety Courses ○ Standard Operating Procedures are written and submitted for review ○ Proper PPE will be worn when working with the battery ■ In this case, Arc Flash Cat 2 PPE ■
BMS and Battery System
FSAE 2020 Specification For Battery and BMS Battery: Battery Management System (BMS) Max power drawn from the Must measure the voltage of ● ● battery must not exceed 80kW. every cell to ensure they remain Max voltage measured between in maximum and minimum cell ● any two points must not exceed voltage levels. 300VDC. Must measure the cell ● Must be fuse protected temperatures of at least 20% of ● the cells, to ensure the temperature stays below 60°C *All of the rules are covered in the FSAE rulebook found on their site
2017 Team’s Selections - Battery and BMS Orion BMS 2 ● Powered with 12VDC, 250mA ● Measures the voltage of up to 72 units ● Can monitor temperature of 8 ● thermistors TNR18650-25R cells in Li8P25RT Building Blocks ● 64 packs, 8 cells in each ● Max voltage of 268VDC, 360A. ● 5.2kWh / 20Ah capacity per pack ● 2 fuses per pack ●
2017 Team’s Selections - Charger and Contactor ● Elcon PFC 2500 TCCH-216-10 ● Custom charging curves KILOVAC LEV200 A4NAA ● ● 120V/60Hz input AC 500+ Amp, 12-900VDC ● ● Output voltage: nominal 216V, Contactor maximum 289V DC High-current protection ● ● Output current: 6A maximum 12VDC coil voltage ● ● CAN communication interface
Thermistor Expansion Module Monitors 80 additional thermistors ● Communicates via CAN ● Allows measurement of every cell’s ● temperatures Battery Thermistors ⇨ Thermistor Module ⇨ CANBUS ⇨ Microcontroller
Temperature Monitoring FSAE requires 13 thermistor modules to read cell temperatures ● A thermistor expansion module, as well as 3 banks of thermistors will add the additional monitoring that we ○ need Not using the bank directly connected to the BMS, due to incompatibility ○ Need to work with M.E. senior design team to determine optimal place to place thermistors based ● on their cooling system ○ Thermistors will not be in the way of their cooling system, however we must ensure the temperatures we’re reading are accurate across the entire battery array
Microcontroller/ Laptop BMS Electric Load Battery System
Battery Charging We would like to ensure the battery system is fully functional before connecting it to the motor ● system We will be testing for: ● Max voltage ○ Capacity ○ Charge time ○ Amperage ○ Temperature ○ How these change as the state of charge (SOC) changes ○ We will continue to perform these tests once the battery and motor are connected ●
Battery Discharging One FSAE test is a 30 minute endurance race ● Looking at the discharge characteristics will give an idea how the battery will perform ● Connecting to artificial load to test discharging characteristics ● Again, looking at: ● Voltage ○ Capacity ○ Discharge time ○ Amperage ○ Temperature ○ How these change as the state of charge (SOC) changes ○ Once the battery system is connected to the motor, these tests will be re-performed ●
Motor System
Motor System Specifications Precharge and Discharge Circuit for the Motor Controller ● According to the FSAE rules and our sponsors guidelines, the circuit “Must be charged to 90% within 5 ○ seconds and discharge to 60V in under 5 seconds.” The motor chosen had to provide a good amount of torque, while keeping power consumption in ● mind. Battery provide up to 268 Volts DC, and 360 Amps ○ Maximum power draw must be limited to 80kW ○ Motor had to handle maximum battery parameters, as well as have good software integration. ●
2017 Team’s Selections - Motor The motor chosen was the EMRAX 208 ● Max Voltage: 320 VDC ○ Max Current: 320 Amps ○ Max Power: 80kW ○ Continuous torque output of 80 ○ Nm, with a peak of 140 Nm (59 and 103 ft-lbs.) Lightweight, at only 9.4 kg (~21 ○ lbs.)
2017 Team’s Selections - Motor Controller The motor controller chosen was the EMSISO ● H300 Allows for Field Oriented ○ Control (FOC) Offers CAN protocol in order to ○ interface with rest of electrical system. Allows for regenerative braking ○ option
Motor and Motor Drive Approach Motor system requires more testing before connected to the battery ● Needs to be tested under dyno load, and tested with a temporary 3KW chiller ○ Torque and speed tests, both under and not under load ■ Chiller will be used until the ME’s cooling system is complete ■ Using EmDrive software and physical hardware, we can modify the parameters of the motor and control its ○ various functions Once testing is complete, we will connect it to the battery and ensure our parameters are correct ● Microcontroller system will also display essential stats and send them to an LCD ●
Testing Rectifier Original testing power supply is currently unavailable, so we need a way to test the motor ● Accomplished via a DC voltage rectifier circuit provided by Dr. Park ● Wall provides 208V 3-phase AC ○ Plugs into AC source to control voltage and current ○ AC source connects to voltage rectifier circuit to output 268V to motor ○
Temporary Chiller Microcontroller System Motor System
Microcontroller System Precharge/ Discharge Circuit Cooling System Final Design
Microcontroller System
Embedded System UCEM wants an embedded system to interface with BMS and motor controller ● We intend to use a microprocessor system to display vital stats in the car on an LCD screen ● State of Battery Charge ○ Throttle Level ○ Forward/Reverse ○ Using CAN (controller area network) to interface with systems directly from controllers ● BMS uses a very common set of CAN addresses under the OBDII protocol, while ○ UCEM team working on microcontroller system as well for low-voltage system, so we are working ● closely with them to create a system that can integrate both of our ideas
Microcontroller Raspberry Pi 3B+ ● Single-board computer running ○ Raspbian Linux 1.4GHz ARM processor, 1GB RAM ○ Four USB 2.0 ports, used to connect ○ to the motor controller and BMS DSI display port to connect a small ○ screen, as well as HDMI for prototyping
Interface Ewert CANdapter ● Converts between RS232 and USB, ○ allowing for CAN signals to be directly read or written to Up to 1Mbps baud rate ○ Developed by the same company ○ who made the ORION Creates a virtual serial port, that can ○ be interfaced directly with the USB port of the microcontroller or a laptop (for use with BMS software)
BMS Motor Controller CANdapter LCD Display Embedded System Proposal
Cooling System Mechanical Engineering senior design team is working on a cooling system for the battery and ● motor One full loop water cooling system, still in the design/simulation phase ○ Must work closely with them in the spring semester to help implement into the full power train ○ This requires us to have communication with them as well in order to ensure any decisions we ● make will not interfere with their cooling system Eg. location of thermistors, correct temperature data, etc. ○
Gantt Chart
Component Qty. Unit Price Total Price Raspberry Pi 3B Kit 1 $45.99 $45.99 Arduino Mega 2560 1 $14.99 $14.99 Micro SD Card, 32GB 1 $5.32 $5.32 20x4 Char. LCD Screen 1 $7.99 $7.99 Quick Disconnect W/ Pins 2 $6.75 $11.50 Misc. Chiller Parts 1 $40.00 $40.00 Grand Total $127.29 Budget
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