Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Motion control and drives

Pulse-width modulation (PWM)

Also known as: PWM, Pulse-duration modulation

German: Pulsweitenmodulation (PWM)

In power electronics, pulse-width modulation (PWM) is a method of controlling the average voltage or current delivered to a load by switching it fully on and off at a fixed frequency and varying the ratio of on-time to period, the duty cycle.

  • Motion control

In one sentence

PWM controls the average voltage or current to a load by switching it on and off fast and varying the on-time ratio (duty cycle).

Example

A stepper driver switches the 24 V supply to each winding at 40 kHz with PWM and adjusts the duty cycle so the phase current stays at 1.2 A.

How it applies

  • Engineering: Motor windings smooth the switched voltage into a nearly continuous current. Higher PWM frequencies reduce current ripple and audible noise but raise switching losses.
  • Commissioning: A PWM frequency in the audible range makes motors whine; frequencies above about 20 kHz are inaudible.
  • Operation: Fast switching edges cause electromagnetic interference and leakage currents through cable capacitance, which cabling and shielding must handle.
  • Documentation: Give the PWM frequency where it matters to installers (cable length, shielding, Electromagnetic compatibility (EMC)) and explain that a PWM-switched output can't be measured correctly with a simple multimeter.

By knowledge.aitechdoc.world · Published September 28, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on power electronics practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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