What is flux weakening in induction motor?

Abstract: Flux-weakening control for induction motor (IM) in voltage extension region (outside the inscribed circle but in the hexagon) is meaningful to yield a further maximum torque. However, as the voltage-limit trajectory migrates out of the inscribed circle, torque ripple becomes more severe.

What does flux weakening mean?

Flux weakening allows a machine to operate above base speed in constant-power, high speed region when there is a fixed inverter voltage and current [7] . Below rated speed, all of the stator current can be used to produce torque. …

What is flux weakening for high speed operation?

The high speed implies a big electromotive force and requires flux-weakening. Usual control algorithms do flux-weakening by adding negative I d current when the required voltage by the current regulation exceeds the maximum voltage depending on the battery.

How does flux weakening work?

Here’s how field weakening is achieved: The d-axis of the stator current is referenced to, or in-line with, the axis of the rotor’s magnetic flux. But back EMF is created by rotor flux. So adding negative d-axis current reduces the rotor flux, which means that back EMF is also reduced.

How does field weakening work?

Field weakening is a method of raising the speed in DC motors. If the field (magnetic field) is weakened by reducing field current, back emf is reduced and thereby more armature current is drawn. Now torque is produced due to interaction of armature current and field flux.

What is field weakening in motor?

Field-weakening or flux-weakening is a technique for increasing the speed of an electric motor above its rating at the expense of reduced torque.

What is flux weakening of Pmsm?

Flux-weakening control of interior permanent magnet synchronous motor (PMSM) is elaborated by presentation of current limit trajectory, speed limit trajectory and load angel limit trajectory. Flux-weakening control extends the timing range of the motor.

What is field weakening?

What is field weakening range?

The frequency range below the nominal frequency is called a constant flux range. Above the nominal frequency/speed the motor operates in the field weakening range. This means that the maximum torque is approximately a constant at the constant flux range.

What is maximum torque per ampere?

Maximum torque per ampere control is also known as unit current output maximum torque control. The basic idea of MTPA control strategy is to find the current operating point that can output the maximum torque under the constant stator current amplitude [22, 23].

Does field weakening increase torque?

Using field weakening, the strength of gap field can be reduced, which reduces the back-EMF for a given speed. The lower back-EMF constant (torque constant) caused by the field weakening thus allows the motor to be run at a higher speed.

What is field weakening in synchronous motor?

What is the field weakening range of an induction motor?

In the field weakening range the motor can operate on constant power which is why the field weakening range is sometimes also called the constant power range. The maximum torque of an induction motor is proportional to the square of the magnetic flux (Tmax ~ ψ²).

What is meant by the term “flux-weakening” in a motor?

Flux-Weakening: Introduction. From the physical point of view, motor operation is constrained by limits in current and power, mainly related to thermal issues, speed (for the mechanical construction of the motor) and voltage, due to the dielectric rigidity of the phase windings.

What is the meaning of 3 phase motor?

July 11, 2019February 24, 2012. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. In the case of three phase AC (Alternating Current) operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device.

What happens when the rotor speed of three phase induction motor increases?

Thus from the working principle of three phase induction motor, it may be observed that the rotor speed should not reach the synchronous speed produced by the stator. If the speeds become equal, there would be no such relative speed, so no emf induced in the rotor, and no current would be flowing, and therefore no torque would be generated.