Status | IN PROGRESS |
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Contributors | |
Approver | |
Due date |
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On this page |
❓ Problem statement
BPS is tasked with securing the safety and monitoring of the battery, such as current monitoring. Over-current of the battery can damage internal components and pose a risk to the driver.
💡 Research insights
There are 2 ways to measure current, either using a shunt resistor connected to the load or using a hall-effect sensor. They have their own pros and cons but they solve the same problem.
📊 Solution hypothesis
The solution is successful if we are able to track current reliably and transmit that data to the leaderboard.
🪛 Design options
There are only 2 ways to measure current. Either measure the voltage across a resistor in series with the load or we can measure the magnetic field of the wire.
Option 1 - Voltage Across a Resistor | Option 2 - Magnetic Field of Wire | |
|---|---|---|
Overview | Current Sense Amplifier or Isolated Modulators/ADC | Hall-Effect Current Sensing |
Screenshot |  |  |
Pros and cons | Accuracy Simplicity and cost Affected by electric noise Power loss and voltage drop | Electric isolation and no power loss Measures both AC and DC current Affected by magnetic noise and temperature Zero-drift problems |
DECISION 1
- Option 1 - Making the PCB though a shunt resistor
In the future, members can look into the second option for a hall-effect version
Ideas
Figure 1 is a common method to measure current using a shunt-resistor. There are # steps to read the current:
The differential voltage is fed into the Current Sense Amplifier and converted to a single-ended signal.
This single-ended signal is connected to an ADC, digitizing the signal.
The signal is sent to a microcontroller for processing.
Current Sense Amplifier | Isolated Modulator | |
|---|---|---|
Design | ||
Accuracy | Bigger shunt resistor allows for more accuracy | |
Power Dissipation | Smaller shunt resistor consumes less power |
✅ Follow up
# | Decision | Status | Next steps |
|---|---|---|---|
1 | COMPLETED |
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2 |
🔤 Vocab
Current Sense Amplifier: Amplifies the small voltage drop across a shunt resistor to measure current accurately in circuits.
Isolated Modulator: Converts analog signals to digital while maintaining electrical isolation, often used in high-voltage or noisy environments.
Hall-Effect Sensor: Detects magnetic fields to measure position, speed, or current without direct electrical contact.
Zero-drift: the phenomenon where a sensor's output signal shifts away from its baseline (or zero) value when there is no actual current flowing through the sensor; affects Hall-Effect Sensor
💎 Resource files
How to Sense Current | Hall-Effect White Paper | Shunt vs Hall-Effect | Isolated Amplifiers vs Isolated Modulators |