What is a field-oriented control?
What is a field-oriented control?
Vector control, also called field-oriented control (FOC), is a variable-frequency drive (VFD) control method in which the stator currents of a three-phase AC or brushless DC electric motor are identified as two orthogonal components that can be visualized with a vector.
What is meant by field-oriented control of induction motor?
The Field-Oriented Control Induction Motor Drive block represents a standard vector or rotor field-oriented control drive for induction motors. This drive features closed-loop speed control based on the indirect or feedforward vector control method.
What is the difference between DTC and FOC?
FOC uses linear controllers and pulse width modulation (PWM) to control the fundamental components of the load voltage. On the other hand, DTC is a nonlinear strategy that directly generates the voltage vectors in the absence of a modulator.
How do you implement FOC?
The steps involved in sensored FOC are as follows:
- Two of the three stator phase currents are measured and the third current is determined using Kirchoff”s current relation,
- The three phase currents are converted into a 2-axis coordinate system from the 3-axis system of the stator, using a Clarke transformation,
Why we use field-oriented control?
Also called vector control, field-oriented control is the most efficient way to drive electrical motors using orthogonal applied current. In short, you can’t simply control the amount of current needed to generate a certain torque.
What are the advantages of field orientation control?
higher top speed and, often just as importantly, higher motor drive efficiency. Motor controllers which adopt an FOC approach can drive the motor more efficiently, as high as 97 % in certain applications. This advantage is particularly pronounced at higher speeds.
Why is it called field-oriented control?
Field Oriented Control describes the way in which the control of torque and speed are directly based on the electromagnetic state of the motor, similar to a DC motor. FOC is the first technology to control the “real” motor control variables of torque and flux.
Is DTC a vector control?
Thus the torque and current ripple are of the same magnitude as with vector controlled drives with the same switching frequency….DTC control platform.
| Scalar control | V/f (Volts per frequency) |
|---|---|
| Vector control | FOC (Field-oriented control) DTC (Direct torque control) DSC (Direct self control) SVM (Space vector modulation) |
What is the difference between VF control and vector control?
1. Vector drives can separately manipulate the voltage and frequency to always produce the optimum V/Hz ratio for maximum torque. In this way, vector drives can generate more starting torque, and can provide full torque down to 1 Hz or less, while V/Hz drives are limited to about 5-6 Hz.
Why it is called field-oriented control?
What is FOC vs BLDC?
Sensorless Field Oriented Control (FOC) is one of the methods used to control a BLDC motor’s speed and torque. Field oriented control (also known as vector control) is a technique used to generate a 3-phase sinusoidal modulation which then can be controlled in frequency and amplitude.
Can FOC be used for BLDC?
FOC, or vector control, is most commonly used on brushless DC (BLDC) or DC motors that utilize permanent magnets. The position of the rotor and the phase of the magnetic field need to be known entities to provide torque to the motor shaft.
