Hysteresis control technique in Power Electronics - Mini Project: Build & Apply

Hysteresis Control Technique

📖 Scenario: You are working on a simple power electronics project where you need to control the output current of an inverter. To keep the current within a safe range, you will use the hysteresis control technique.This technique helps maintain the current close to a reference value by switching the inverter output on or off depending on the current's position relative to upper and lower limits.

🎯 Goal: Build a step-by-step understanding of the hysteresis control technique by defining the reference current, setting hysteresis band limits, applying the control logic, and completing the control decision process.

📋 What You'll Learn

Define a reference current value

Set upper and lower hysteresis band limits

Implement the hysteresis control logic to decide switching

Complete the control decision with output switching states

💡 Why This Matters

🌍 Real World

Hysteresis control is widely used in power electronics to maintain current or voltage within safe limits, improving device reliability and efficiency.

💼 Career

Understanding hysteresis control is essential for engineers working with inverters, motor drives, and power converters in industries like renewable energy, automotive, and manufacturing.

1

Define the reference current

Create a variable called i_ref and set it to the exact value 10.0 representing the reference current in amperes.

Power Electronics

# Create the reference current variable i_ref
# Your code here

Need a hint?

The reference current is the target current you want to maintain using hysteresis control.

2

Set hysteresis band limits

Create two variables called upper_limit and lower_limit. Set upper_limit to i_ref + 0.5 and lower_limit to i_ref - 0.5 to define the hysteresis band around the reference current.

Power Electronics

i_ref = 10.0
# Define upper_limit and lower_limit for hysteresis band
# Your code here

Need a hint?

The hysteresis band creates a range around the reference current to decide when to switch the output.

3

Implement hysteresis control logic

Create a variable called i_actual and set it to 10.3 representing the measured current. Then write an if-else statement that sets a variable switch_state to "OFF" if i_actual is greater than upper_limit, and to "ON" if i_actual is less than lower_limit. If i_actual is within the band, keep switch_state unchanged and initialize it to "ON" before the conditions.

Power Electronics

i_ref = 10.0
upper_limit = i_ref + 0.5
lower_limit = i_ref - 0.5
# Define i_actual and hysteresis control logic
# Your code here

Need a hint?

This logic turns the switch off if the current is too high, on if too low, and keeps it on if within limits.

4

Complete the hysteresis control decision

Add a final line that creates a variable called output_signal and sets it to 1 if switch_state is "ON", or 0 if switch_state is "OFF". Use a simple if-else statement for this.

Power Electronics

i_ref = 10.0
upper_limit = i_ref + 0.5
lower_limit = i_ref - 0.5
i_actual = 10.3
switch_state = "ON"
if i_actual > upper_limit:
    switch_state = "OFF"
elif i_actual < lower_limit:
    switch_state = "ON"
# Set output_signal based on switch_state
# Your code here

Need a hint?

The output signal controls the inverter switch: 1 means switch on, 0 means switch off.