Electric Car Tractive System
AUTHOR NAME: Jerico M. STUDENT NUMBER: C15580367 COURSE: DT021A/TU821
Week 4 Objectives
basgsagdsagdsagadsgdsagsadgdsagasgsadgdsagsadgasadgasgdsagsadgadsgasgaThe main objectives for this week include both close coordination with other Kevin St. students that have projects on the EV which are Raimonds Kaminskis and Niall Beggan. Overall objectives for the projects along with my project objectives for this week are:
- Attend meeting with supervisors: Monday 17/02
- Put together an overall project plan between all three projects
- Initialize an Excel spreadsheet of all the signals that will be used in each of our projects
- Obtain motor hall-effect current sensors
- Research the Battery Management System installed on the EV
- Update the Tractive System (TS) and Low Voltage Control & Safety System (LVCSS) wiring diagrams
- Attend formula team meeting: Friday 21/02
Overall Project Progress
asgsagdsagdsagadsgdsagsadgdsagasgsadgdsagsadgasadgasgdsagsadgadsgasgasTo ensure that communication between my peers are optimal, I made a common drive between us to ensure that we keep each other up to date on each of our progress so that we meet deadlines for each part simultaneously or as close as possible. With the common drive set up, the following objectives have been started to have a clear outline of everything we will need.
Overall Project Plan
Current objectives for the week are laid out after meeting with supervisors on a weekly basis, along with further objective plans for the following weeks, for example for the next few weeks, the main objectives can be seen below in Figure 1 where the LVCSS must be fully wired in three weeks time which is a very high priority to ensure the EV is completed by the end of March, this is a key milestone for my part of the project. Other objectives that will be focused on would also be to start implementing and testing sensors that will be used for the TS, i.e. hall-effect current sensors for the BMS and motors. Some tasks might have to be postponed and new tasks could be added to the plan below in Figure 1 depending on the progress or issues that might come up during these weeks, so the project plan is subject to change.
Figure 1: Project Plan for the Next Three Weeks (Week 4)
Sensor List Audit
The following sensors that have been acknowledged so far are:
- 3x hall effect current sensors
- 1x hall effect current sensor for front left motor
- 1x hall effect current sensor for front right motor
- 1x hall effect current sensor for the battery system
- 3x hall effect voltage sensors
- 1x hall effect voltage sensor for front left motor
- 1x hall effect voltage sensor for front right motor
- 1x hall effect voltage sensor for the battery system
- Temperature sensors for the battery system
- 1x accelerometer
- 1x brake position sensor
- 1x steering position sensor
- 1x pressure sensor
- 4x linear potentiometers
Formula Team Meeting
With mechanical and electrical students of the formula team finishing their projects on different times, objectives and plans for the EV have to be adjusted to ensure that the car is put back together by the end of March and that it satisfies all of the regulatory and safety criteria laid out by the ImechE, primary objectives and key points were discussed in the team meeting for the coming weeks:
- Testing along with results must be started and obtained during early April
- All essential parts in regards to safety and regulations for both the mechanical and electrical side must be complete by end of March
- LVCSS need to be transferred to the new casing, this includes the following:
- Neat cable management
- Cable colour coding
- Cable and component labels
- Implementation of LVCSS to TS and how it will be wired around the car
- Solder Arduino pins to ensure secure connections
- Remove fault points such as the grey clip-on connectors since they are prone to vibrations
- Driver safety and driver training (Kart race where driver will be chosen out of the top four candidates from the team)
EV Tractive System Progress
asgsagdsagdsagadsgdsagsadgdsagasgsadgdsagsadgasadgasgdsagsadgadsgasgasThe main goal of this project is to ensure that the EV will be eligible for the competition at Silverstone by July 2020, with Kevin St. students finishing up their projects in May and mechanical students from Bolton St. finishing up in early March. For the electrical/electronic engineering side, the Tractive System (TS) is the main part of the vehicle that will be handled. The TS has already been designed by previous students in 2019, so adjustments are required for the car which will be discussed below.
TS and LVCSS Wiring Diagram 2019 Design
The main confusion from the TS wiring diagram designed by Philip Malone and the LVCSS wiring diagram designed by David Reynolds resulted mainly from the Positive and Negative Accumulator Isolation Relays (AIR). Snips from the final wiring diagrams can be seen below for Figure 2 and Figure 3, comparing these parts of the designs, it can be seen that there were mistakes in terms of labeling:
TS ID LVCSS ID Cable ID Component Description
RLY1 LVPR 1.21 20 Pre-charge Relay
CNT1 LVR 1.22 21 Positive Accumulator Isolation Relay
CNT2 LVR 1.23 19 Negative Accumulator Isolation Relay
Figure 2: TS Wiring Diagram Precharge & AIR Circuit
Figure 3: LVCSS Wiring Diagram Precharge & AIR Circuit
TS and LVCSS Wiring Diagram 2020 Updated Design
The following update was made to the TS and LVCSS drawing to have a finalized version before April, which can be seen below in Figure 4 and Figure 5, note that wiring diagram component IDs, cable IDs and tables for both TS and LVCSS had to be updated.
Figure 4: TS Wring Diagram Precharge & Air Circuit (Updated)
Figure 5: LVCSS Wiring Diagram Precharge & AIR Circuit (Updated)
Hall-effect Current Sensor for Motors
From meeting with the technicians and supervisors, the current transducers for the motor were obtained, which were the LA 205-S Current Transducers supplied by LEM. These sensors are perfect for current measurement as it satisfies all requirements to measure motor currents with the datasheet showing its specifications below in Figure 5:
Figure 6: LEM LA 205-S Current Transducer Specifications
These current transducers are suitable for current measurements due to the following:
- Measures up to 300A when motor max currents reach about 250A
- Measures within temperature range of motors being used
- It is a hall-effect sensor, suitable for the EV
- The only problem is the datasheet does it specify if it is bidirectional, since bidirectional will be needed if regenerative mode will be applied to the EV
Battery Management System (BMS)
After the formula team meeting on Friday 21/02/20, I talked to Michael who is doing a project on the accumulator system and battery management system of the EV. After thorough research with the installed BMS which is the EMUS G1 BMS, I created the block diagram below in Figure 7 to show how the system operates:
Figure 7: EMUS G1 BMS Block Diagram Breakdown
LVCSS Lamp Issues
With regards to the lamps of the physical LVCSS, there was confusion with the operation when testing the actual system where it was hard to determine which lamp was which due to the poor cable management of the physical system. Eventually the four main lamps of the system which are the:
Cable ID LVCSS ID Component Description
31 LVL 1.40 AMS Trip Lamp
29 LVL 1.37 IMD Trip Lamp
45 LVL 1.58 Low Voltage System Active Lamp
46 LVL 1.59 Tractive System Active Flashing Lamp
On the physical LVCSS LVL 1.40 AMS Trip Lamp and LVL 1.37 IMD Trip Lamp were just small red lamps, throughout the test these lamps should remain OFF as the IMD is currently not installed in the LVCSS while there should also be nothing tripping the AMS. The other two lamps were the LVL 1.58 Low Voltage System Active Lamp and LVL 1.59 Tractive System Active Flashing Lamp, where for the TS lamp, it was represented by a green lamp when the TS is inactive and a red lamp when the TS is active. These were identified after multiple testing of the system and tracking of each connection from the lamps to the rest of the system.
Week 4 Objectives Checklist
asgsagdsagdsagadsgdsagsadgdsagasgsadgdsagsadgasadgasgdsagsadgadsgasgasRed = Incomplete Green = Complete
- Attend meeting with supervisors: Monday 17/02
- Put together an overall project plan between all three projects
- Initialize an Excel spreadsheet of all the signals that will be used in each of our projects
- Obtain motor hall-effect current sensors
- Research the Battery Management System installed on the EV
- Update the Tractive System (TS) and Low Voltage Control & Safety System (LVCSS) wiring diagrams
- Attend formula team meeting: Friday 21/02
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