Industrial electronics
It is like…
Sine PWM Is Like a Dot-Painted Picture
Sinusoidal PWM is like painting a smooth curve with dots
Quick check · tap an answer to continue
Lesson notes
Key points
- Picture an artist who only has black dots, yet draws a smooth grey wave by packing dots densely or sparsely.
- In an inverter, each dot is a full-voltage pulse, and wider pulses where the sine peaks make the average follow a sine wave.
- The analogy breaks because pulse widths come from comparing a sine reference with a fast triangle carrier, and leftover harmonics sit near the carrier frequency.
Definitions
- Modulation index
- Ratio of sine reference amplitude to triangle carrier amplitude; it sets the fundamental output voltage.
Takeaway: Sine PWM varies pulse width so the average traces a sine wave.
Quick check: In sine PWM, what is compared with the triangle carrier to set pulse widths?
- A square-wave clock
- A sine reference signal
- The load current
Switching occurs where the sine reference crosses the triangle carrier.
Dot densityPulse widthCarrier harmonics
Lessons like this, for your syllabus.
Short narrated study videos written for your course, level and exam. Free to start.
Get lessons for your own syllabus