Industrial Engineer · phase 11 of 16 · noun
Sensorless Vector Control
Control method that estimates motor flux, speed, or torque from electrical measurements and a motor model without an encoder.
The Explain card
- Plain English
- Sensorless vector control estimates what the motor is doing from the current and voltage the drive can already measure, using a mathematical model of the motor. No encoder, and yet the drive controls flux and torque separately.
- Example
- A mixer needs strong torque at low speed to start a thick batch. In sensorless vector mode the drive holds rated torque down to a couple of hertz, where V/Hz would stall.
- Why it matters
- It is the default mode on most modern drives and gives most of the benefit of a vector drive with none of the feedback wiring. The model only works if the motor data and the autotune are right, and a wrong model is worse than no model.
- Hook
- Vector control that reads the motor instead of watching the shaft.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, the technician selects Sensorless Vector Control, enters the induction motor nameplate data, and runs the drive's static autotune.
Why these words
- sensorless English sensor plus the suffix -less specifies the absence of a separate sensing device
- vector Latin vector, carrier links the phrase to vector-based analysis and control
- control Middle English from Anglo-French contrerolle, a checking register names the phrase as a method of regulation
Where it came from
- Origin
- English engineering compound formed from sensorless and vector control
- Entered the language
- 1980s
- What changed
- Vector moved from the Latin sense of carrier to a mathematical quantity and then to coordinate-based motor-control terminology; sensorless became a productive engineering modifier.
How it is spelled
- Pattern
- Sensorless is written as one word with the suffix -less.
- Pattern
- Vector control remains an open compound of two words.
- Pattern
- The full term is conventionally written as three separate words.
Spelled like
- brushless
- wireless
- encoderless
Broken into chunks
-
sensor
- sensing
- sensory
- sensor
-
-less
- brushless
- wireless
- gearless
-
vector
- vectorial
- vectoring
-
control
- controller
- controllable
- controlled
What it sits beside
Same subject
- field-oriented control
- motor autotune
- slip compensation
- speed feedback
- variable frequency drive
Same shape
- encoderless vector control
- closed-loop vector control
- open-loop vector control
VFD control modes
- volts-per-hertz control
- Sensorless Vector Control
- closed-loop vector control
motor feedback terms
- encoder feedback
- resolver feedback
- speed feedback
Where it sits in the deck
Phase 11: VFD Control Modes and Tuning
How a drive decides what to send the motor, from plain volts per hertz up to closed loop vector control, and how each mode is tuned.
