Electric Car Tractive System
AUTHOR NAME: Jerico M. STUDENT NUMBER: C15580367 COURSE: DT021A/TU821
Week 6 Objectives
basgsagdsagdsagadsgdsagsadgdsagasgsadgdsagsadgasadgasgdsagsadgadsgasgaMain objectives this week and the next few weeks will revolve around all of the stuff that will need to be put on the car before it is fully built, thus parts, sensors and extra parts that need to be added on the EV must be acknowledged and implemented before the end of March.
- Attend meeting with supervisors: Monday 02/03/20
- Spec a suitable speed sensor for the EV
- Implement the LA 205-S hall-effect current sensor with the Arduino
- Create list of all parts that will be needed for our projects, along with parts that will be needed for the overall EV i.e. Parts for LVCSS
- Start research into logging sensor data onto an SD card using the Arduino
- Design a suitable battery/supply that will be used for the LVCSS and Arduinos
- Work at Bolton Street workshop: Friday 06/03/20
Overall Project Progress
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Supervisor Meeting Summary (Week 6)
Meeting the supervisors on Monday 02/03/20, the progress on last weeks objectives were briefly discussed and a few new objectives were identified on top of the objective specified in Week 5, thus the objectives from last week, along with new objectives will be discussed below.
Objectives for the next few weeks (Specified in Week 5)
Red = Incomplete Green = Complete Orange = Postponed
- Rewiring of the LVCSS, this includes:
- Obtaining cable IDs from the technicians
- Creating a colour-code scheme for the cables
- Improve cable management and component positioning on the LVCSS
- Fit it to the new case and make necessary rearrangements
- Get rid of fault points by getting rid of the grey connectors or obtaining more secure connectors as they will be needed for maintenance
- Getting an update from Lowry to see his progress with the other sensors on the EV:
- Speed sensor
- Steering position sensor
- Brake position sensor
- Getting an update from Michael on the BMS measurements over CAN including:
- BMS temperature measurements CAN ID
- BMS voltage measurements CAN ID
- BMS current measurements CAN ID
- Instrumentation on the EV and CAN bus implementation:
- Motor current measurements (LA 205-S)
- Motor voltage measurements (LA 205-S)
- BMS measurements as mentioned above:
- BMS temperature measurements (BMS Cell Modules)
- BMS voltage measurements (BMS Cell Modules)
- BMS current measurements (G1 Close Loop Dual Range Current Sensor)
Objectives for the next few weeks (Week 6)
- Additional LVCSS requirements for rewiring:
- Identify and list parts that will be needed for rewiring
- Design 12V supply for the LVCSS and Arduinos
- Changes needed for Lowry’s Arduino:
- Implement on to the LVCSS Arduino a watchdog timer that will be connected to Lowry’s Arduino to track if his Arduino is operating, if his Arduino is not operating, the LVCSS Arduino can be set to shut the system down
- Implement CAN bus on Lowry’s Arduino
- Test Lowry’s Arduino for the fault where when his Arduino dies, the drives still make the motors run at full speed, instead of stopping, analog value can be set to zero to see if this can fix this issue
- For Instrumentation of the EV new objectives outlined were:
- Log motor current and voltage measurements (LA 205-S) on to an SD card using the Arduino
- Track the power from the TS to ensure it does not go above 80kW as specified in the Formula Rulebook, must be applied to the driver GUI
Overall Project Plan
Although the deadline for the objective of rewiring the LVCSS has already been discussed with the supervisors and the mechanical team which is around the 13th of March, due to extra parts being needed before being able to even start rewiring, the deadline must be extended along with the milestone for the instrumentation of the EV, i.e. LA 205-S current sensors for the motors and BMS CAN IDs. Thus in Figure 1, the project plan has been updated with the new objectives mentioned previously, along with new milestones to show when they are expected to be completed between this week (Week 6) and the following weeks.
Figure 1: Project Plan for the Next Three Weeks (Week 6)
EV Tractive System & LVCSS Progress
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LVCSS Rewiring Progress
After the progress of implementing the LVCSS into the new case last week, progress on rewiring the LVCSS has come to a halt because there are some parts that we need before we can start any of the other parts such as changing the colour-coding and labelling of the cables, thus a parts list needed to be ordered was made as shown in Figure 2 below, this includes spares that we would need, parts for rewiring the LVCSS, etc…:
Figure 2: List of Parts Needed to be Ordered
On top of this list, the following things were also completed and agreed upon with the mechanical students for the LVCSS:
- Mount for the NANO for the LVCSS was made, which can be successfully used to replace the UNO to maximize spacing in the case
- All cables will be going into a single loom instead for neater cable management, this will be carried out by Sean
- Cable colour coding scheme has also been agreed upon, with the limited colours we have in the workshop:
- Red: Switches/buttons
- Black: Ground
- Orange: Contactors
- White: Lamps
Speed Sensor for the EV
After talking to Lowry at the end of Week 5 and successfully testing out the SR17C-J6 sensor as mentioned in last weeks blog, at the start of this week, a new, more suitable sensor that must be mountable on one side of the gear tooth disc was specced, thus the table show below in Table 1 was constructed after looking through multiple websites. The Criteria for this table can be split up as followed:
Specs: This takes into account the voltage range, air gap, temperature range, etc… This is the highest weight as it is the most important factor when it comes to sensors for the EV.
Size: The reason size is the second most important factor is because of the current design of where the sensor is gonna be placed. The size of the sensor is important as it is needed for the gear disc design i.e. How many teeth is needed, mount design for the sensor, etc… The size weight was based on the desired diameter size = 8mm and length size = 30mm.
Range: Another characteristic mentioned in the criteria is the frequency range, all of these sensors have almost identical ranges, although the Honeywell 1GT10DC is given the lowest weight as it has a smaller operating frequency range of up to 10kHz compared to the other four sensors which has ranges of up to 15kHz.
Cost: When it comes to any component selection, cost is also an important factor, although the websites that I looked at were all accessible and easy to order from, sensor costs varied between €25 to €100, thus each sensor was weighted accordingly.
Availability: Due to shipping issues from these websites due to COVID-19, some sensors became unavailable within days of speccing the different sensors, thus availability was also important to mention in the criteria. The weight of the availability includes how long shipping of sensors would take, current stock of sensors in the websites and if it is purchasable through multiple websites, thus the weights below were applied based on these factors.
Table 1: Speed Sensor Selection: Weighted Factor Model
LEM LA 205-S Hall-effect Current Sensor
For this week I have completed the circuit needed to implement the LA 205-S hall-effect current sensors along with an Arduino code to extract current measurements for it, although due to safety measures, the implementation of this will have to be extended to Week 7 to get supervisor feedback to ensure that the circuit and code is safe and correct before being attempted, thus comparing the project plan from Week 5 to the project plan in Figure 1 for Week 6, the milestone has been adjusted accordingly.
Week 6 Objectives Checklist
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- Attend meeting with supervisors: Monday 02/03
- Spec a suitable speed sensor for the EV
- Implement the LA 205-S hall-effect current sensor with the Arduino
- Create list of all parts that will be needed for our projects, along with parts that will be needed for the overall EV i.e. Parts for LVCSS
- Start research into logging sensor data onto an SD card using the Arduino
- Design a suitable battery/supply that will be used for the LVCSS and Arduinos
- Work at Bolton Street workshop: Friday 06/03
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