BMS communication protocols (CAN bus) in Power Electronics - Mini Project: Build & Apply

Understanding BMS Communication Protocols: CAN Bus

📖 Scenario: You are working with a Battery Management System (BMS) that uses the CAN bus protocol to communicate battery status to other vehicle systems. Understanding how data is structured and sent over CAN bus is essential for monitoring and controlling battery health.

🎯 Goal: Build a simple representation of CAN bus messages used in BMS communication. You will create a data structure for CAN messages, configure message identifiers, extract key data fields, and finalize the message format for transmission.

📋 What You'll Learn

Create a dictionary representing CAN messages with specific message IDs and data fields

Add a configuration variable for the standard CAN message ID format

Extract battery voltage and temperature from the CAN message data using dictionary comprehension

Complete the CAN message structure by adding a checksum field

💡 Why This Matters

🌍 Real World

BMS systems in electric vehicles use CAN bus to send battery voltage and temperature data to controllers for safe operation.

💼 Career

Understanding CAN bus communication is essential for engineers working on battery management, automotive electronics, and embedded systems.

1

Create CAN messages dictionary

Create a dictionary called can_messages with these exact entries: 0x100 mapped to {'voltage': 360, 'temperature': 25}, and 0x101 mapped to {'voltage': 355, 'temperature': 27}.

Power Electronics

# Create the can_messages dictionary with specified message IDs and data
# Your code here

Need a hint?

Use hexadecimal keys for message IDs and dictionaries for data fields.

2

Add CAN ID format configuration

Add a variable called can_id_format and set it to the string 'standard' to represent the standard CAN message ID format.

Power Electronics

can_messages = {
    0x100: {'voltage': 360, 'temperature': 25},
    0x101: {'voltage': 355, 'temperature': 27}
}
# Define the CAN ID format
# Your code here

Need a hint?

This variable helps specify the type of CAN ID used in communication.

3

Extract voltage and temperature data

Use dictionary comprehension to create a new dictionary called battery_data that extracts 'voltage' and 'temperature' from each message in can_messages. Use msg_id and data as loop variables.

Power Electronics

can_messages = {
    0x100: {'voltage': 360, 'temperature': 25},
    0x101: {'voltage': 355, 'temperature': 27}
}
can_id_format = 'standard'
# Extract voltage and temperature into battery_data
# Your code here

Need a hint?

Use dictionary comprehension with msg_id and data to extract fields.

4

Add checksum to CAN messages

Add a new key 'checksum' with value 0xAB to each dictionary in can_messages using a for loop with variables msg_id and data.

Power Electronics

can_messages = {
    0x100: {'voltage': 360, 'temperature': 25},
    0x101: {'voltage': 355, 'temperature': 27}
}
can_id_format = 'standard'
battery_data = {msg_id: {'voltage': data['voltage'], 'temperature': data['temperature']} for msg_id, data in can_messages.items()}
# Add checksum 0xAB to each CAN message
# Your code here

Need a hint?

Use a for loop to add the checksum key to each message dictionary.