

Add to Cart
180kw Water Cooled High Torque Three Phase Permanent Magnet Motor
What Is The Permanent Magnet Synchronous Motor?
The PERMANENT MAGNET SYNCHRONOUS MOTOR is mainly composed of the
stator, rotor, chassis, front-rear cover, bearings, etc. The
structure of the stator is basically the same as that of ordinary
asynchronous motors, and the main difference between the permanent
magnet synchronous motor and other kinds of motors is its rotor.
The permanent magnet material with pre-magnetized (magnetic
charged) magnetic on the surface or inside the permanent magnet of
the motor, provides the necessary air gap magnetic field for the
motor. This rotor structure can effectively reduce the motor
volume, reduce loss and improve efficiency.
Structure of the IPM (interior permanent magnet) motor
PM motor structures can be separated into two categories: interior
and surface. Each category has its subset of categories. A surface
PM motor can have its magnets on or inset into the surface of the
rotor, to increase the robustness of the design. An interior
permanent magnet motor positioning and design can vary widely. The
IPM motor’s magnets can be inset as a large block or staggered as
they come closer to the core. Another method is to have them
embedded in a spoke pattern.
SPM vs IPM Motor Rotor Structure
IPM (Interior Permanent Magnet) Motor Features
High torque and high efficiency
High torque and high output are achieved by using reluctance torque
in addition to magnetic torque.
Energy-saving operation
It consumes up to 30% less power compared to conventional SPM
motors.
High-speed rotation
It can respond to high-speed motor rotation by controlling the two
types of torque using vector control.
Safety
Since the permanent magnet is embedded, mechanical safety is
improved as, unlike in an SPM, the magnet will not detach due to
centrifugal force.
Vector Control Features
While a conventional system (120-degree conduction system) has the
current impressed in the motor as a square wave, a vector control
impresses voltage which turns into a sine wave towards the rotor's
position (angle of the magnet), so it becomes possible to control
the motor current.
Working of Permanent Magnet Synchronous Motor:
The working of the permanent magnet synchronous motor is very
simple, fast, and effective when compared to conventional motors.
The working of PMSM depends on the rotating magnetic field of the
stator and the constant magnetic field of the rotor. The permanent
magnets are used as the rotor to create constant magnetic flux and
operate and lock at synchronous speed. These types of motors are
similar to brushless DC motors.
The phasor groups are formed by joining the windings of the stator
with one another. These phasor groups are joined together to form
different connections like a star, Delta, and double and single
phases. To reduce harmonic voltages, the windings should be wound
shortly with each other.
When the 3-phase AC supply is given to the stator, it creates a
rotating magnetic field and the constant magnetic field is induced
due to the permanent magnet of the rotor. This rotor operates in
synchronism with the synchronous speed. The whole working of the
PMSM depends on the air gap between the stator and rotor with no
load.
If the air gap is large, then the windage losses of the motor will
be reduced. The field poles created by the permanent magnet are
salient. The permanent magnet synchronous motors are not
self-starting motors. So, it is necessary to control the variable
frequency of the stator electronically.
The rotor pole of the rare earth permanent magnet motor is composed
of rare earth permanent magnet steel, so there is no slip, no
excitation current, and the rotor has no fundamental wave iron and
copper wear.
The rotor is excited by permanent magnets, and no reactive
excitation current is needed. Therefore, the power factor is
improved, the reactive power is reduced, the stator current is
greatly reduced, and the stator copper and iron losses are greatly
reduced.
At the same time, because the polar arc coefficient of the rare
earth permanent magnet motor is larger than that of the
asynchronous motor when the voltage and the stator structure are
constant, the average magnetic induction intensity of the motor is
smaller than that of the asynchronous motor and the iron loss is
small.
Therefore, it can be said that the rare earth permanent magnet
synchronous motor is energy-saving by reducing its own losses, and
is not affected by changes in operating conditions, environment,
and other factors.
Flux weakening/intensifying of PM motors:
Flux in a permanent magnet motor is generated by the magnets. The flux field follows a certain path, which can be boosted or opposed. Boosting or intensifying the flux field will allow the motor to temporarily increase torque production. Opposing the flux field will negate the existing magnet field of the motor. The reduced magnet field will limit torque production, but reduce the back-emf voltage. The reduced back-emf voltage frees up the voltage to push the motor to operate at higher output speeds. Both types of operation require additional motor current. The direction of the motor current across the d-axis, provided by the motor controller, determines the desired effect.