PWM control for inverters in Power Electronics - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the basic PWM frequency variable.

Power Electronics

pwm_frequency = [1]  # in Hertz

Drag options to blanks, or click blank then click option'

A1000

B50

C0.5

D50000

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing too low frequency like 50 Hz causes poor output waveform.

Using extremely high frequency like 50000 Hz increases switching losses.

The PWM frequency for inverter control is typically set around 1000 Hz to balance switching losses and output quality.

2fill in blank

medium

Complete the code to calculate the duty cycle for a given modulation index.

Power Electronics

duty_cycle = [1] * modulation_index

Drag options to blanks, or click blank then click option'

A0.5

Bpwm_frequency

Cmodulation_index

Dswitching_period

Attempts:

3 left

💡 Hint

Common Mistakes

Using frequency instead of a scaling factor.

Multiplying by modulation_index twice.

The duty cycle is calculated by multiplying the modulation index by 0.5 to scale it between 0 and 1 for PWM signals.

3fill in blank

hard

Fix the error in the code that generates the PWM signal based on the carrier and reference signals.

Power Electronics

pwm_signal = 1 if reference_signal > [1] else 0

Drag options to blanks, or click blank then click option'

Aswitching_period

Bmodulation_index

Cpwm_frequency

Dcarrier_signal

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing reference signal with modulation index.

Using frequency value in comparison.

The PWM signal is generated by comparing the reference signal with the carrier signal, not the modulation index or frequency.

4fill in blank

hard

Fill both blanks to create a dictionary mapping inverter phases to their PWM duty cycles.

Power Electronics

phase_duty_cycles = {'A': [1], 'B': [2]

Drag options to blanks, or click blank then click option'

Aduty_cycle_A

Bduty_cycle_B

Cmodulation_index

Dpwm_frequency

Attempts:

3 left

💡 Hint

Common Mistakes

Using modulation_index or pwm_frequency instead of duty cycle variables.

Each inverter phase has its own duty cycle variable, which are assigned in the dictionary for control.

5fill in blank

hard

Fill all three blanks to create a filtered output voltage dictionary for the inverter phases.

Power Electronics

filtered_voltage = { 'A': [1], 'B': [2], 'C': [3] }

Drag options to blanks, or click blank then click option'

Avoltage_A_filtered

Bvoltage_B_filtered

Cvoltage_C_filtered

Dmodulation_index

Attempts:

3 left

💡 Hint

Common Mistakes

Using modulation_index instead of filtered voltage variables.

The filtered voltages for each phase are stored in the dictionary to represent the inverter output after PWM filtering.