QINGDAO ENNENG MOTOR CO.,LTD.
QINGDAO ENNENG MOTOR CO.,LTD.
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Energy Saving Small Size High-Efficiency Interior Permanent Magnet Motor
What Is The Permanent Magnet Synchronous Motor?
The Permanent Magnet Synchronous Motor (PMSM) is a type of electric motor that operates using permanent magnets embedded in its rotor. It is also sometimes referred to as a brushless AC motor or a synchronous permanent magnet motor.
In a PMSM, the stator (the stationary part of the motor) contains a series of coils that are energized in a sequence to create a rotating magnetic field. The rotor (the rotating part of the motor) contains a series of permanent magnets that are arranged to produce a magnetic field that interacts with the magnetic field produced by the stator.
As the two magnetic fields interact, the rotor rotates, producing mechanical energy that can be used to power machinery or other devices. Because the permanent magnets in the rotor provide a strong, constant magnetic field, PMSMs are highly efficient and require less energy to operate than other types of electric motors.
PMSMs are used in a wide variety of applications, including electric vehicles, industrial machinery, and household appliances. They are known for their high efficiency, low maintenance requirements, and precise control, which makes them a popular choice for many different types of systems.
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.
Analysis of the principle of the technical advantages of permanent magnet motor
The principle of a permanent magnet synchronous motor is as follows: In the motor's stator winding into the three-phase current, after the pass-in current, it will form a rotating magnetic field for the motor's stator winding. Because the rotor is installed with the permanent magnet, the permanent magnet's magnetic pole is fixed, according to the principle of magnetic poles of the same phase attracting different repulsion, the rotating magnetic field generated in the stator will drive the rotor to rotate, The rotation speed of the rotor is equal to the speed of the rotating pole produced in the stator.
Back-emf waveform:
Back emf is short for back electromotive force but is also known as the counter-electromotive force. The back electromotive force is the voltage that occurs in electric motors when there is a relative motion between the stator windings and the rotor’s magnetic field. The geometric properties of the rotor will determine the shape of the back-emf waveform. These waveforms can be sinusoidal, trapezoidal, triangular, or something in between.
Both induction and PM machines generate back-emf waveforms. In an induction machine, the back-emf waveform will decay as the residual rotor field slowly decays because of the lack of a stator field. However, with a PM machine, the rotor generates its own magnetic field. Therefore, a voltage can be induced in the stator windings whenever the rotor is in motion. Back-emf voltage will rise linearly with speed and is a crucial factor in determining maximum operating speed.
Permanent magnet AC (PMAC) motors have a wide range of applications including:
Industrial Machinery: PMAC motors are used in a variety of industrial machinery applications, such as pumps, compressors, fans, and machine tools. They offer high efficiency, high power density, and precise control, making them ideal for these applications.
Robotics: PMAC motors are used in robotics and automation applications, where they offer high torque density, precise control, and high efficiency. They are often used in robotic arms, grippers, and other motion control systems.
HVAC Systems: PMAC motors are used in heating, ventilation, and air conditioning (HVAC) systems, where they offer high efficiency, precise control, and low noise levels. They are often used in fans and pumps in these systems.
Renewable Energy Systems: PMAC motors are used in renewable energy systems, such as wind turbines and solar trackers, where they offer high efficiency, high power density, and precise control. They are often used in the generators and tracking systems in these systems.
Medical Equipment: PMAC motors are used in medical equipment, such as MRI machines, where they offer high torque density, precise control, and low noise levels. They are often used in the motors that drive the moving parts in these machines.
Depending on how magnets are attached to the rotor and the design of the rotor, permanent magnet synchronous motors can be classified into two types:
Surface permanent magnet synchronous motor (SPMSM)
Interior permanent magnet synchronous motor (IPMSM).
SPMSM mounts all magnet pieces on the surface, and IPMSM places magnets inside the rotor.
Advantages
Small And Lightweight
In special electromagnetic and structural design, the volume-to-weight ratio is reduced by 20%, the length of the whole machine is reduced by 10%, and the full rate of stator slots is increased to 90%.
Highly Integrated
The motor and the inverter are highly integrated, avoiding the external circuit connection between the motor and the inverter, and improving the reliability of the system products.
Energy Efficient
High-performance rare-earth permanent magnet material, special stator slot, and rotor structure make this motor efficient up to IE4 standard.
Custom Design
Customized design and manufacture, dedicated to special machines, reduce redundant functions and design margins and minimize costs.
Low Vibration And Noise
The motor is directly driven, the equipment noise and vibration are small, and the impact on the construction work environment is reduced.
Maintenance Free
No high-speed gear parts, no need to change gear lubricant regularly, and truly maintenance-free equipment.
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.
What applications use PMSM motors?
Industries that use PMSM motors include Metallurgical, Ceramic, Rubber, Petroleum, Textiles, and many others. PMSM motors can be designed to operate at synchronous speed from a supply of constant voltage and frequency as well as Variable Speed Drive (VSD) applications. Widely used in electric vehicles (EVs) due to high efficiency and power and torque densities, they are generally a superior choice in high torque applications such as mixers, grinders, pumps, fans, blowers, conveyors, and industrial applications where traditionally induction motors are found.
Permanent magnet synchronous motors with internal magnets: Maximum energy efficiency
The permanent magnet synchronous motor with internal magnets (IPMSM) is the ideal motor for traction applications where the maximum torque does not occur at maximum speed. This type of motor is used in applications that require high dynamics and overload capacity. And it is also the perfect choice if you want to operate fans or pumps in the IE4 and IE5 range. The high purchase costs are usually recouped through energy savings over the run time, provided that you operate it with the right variable frequency drive.
Our motor-mounted variable frequency drives use an integrated control strategy based on MTPA (Maximum Torque per Ampere). This allows you to operate your permanent magnet synchronous motors with maximum energy efficiency. The overload of 200 %, the excellent starting torque, and the extended speed control range also allow you to fully exploit the motor rating. For fast recovery of costs and the most efficient control processes.
Permanent magnet synchronous motors with external magnets for classic servo applications
Permanent magnet synchronous motors with external magnets (SPMSM) are ideal motors when you need high overloads and rapid acceleration, for example in classic servo applications. The elongated design also results in low mass inertia and can be optimally installed. However, one disadvantage of the system consisting of SPMSM and variable frequency drive is the costs associated with it, as expensive plug technology and high-quality encoders are often used.
Why you should choose an IPM motor instead of an SPM?
1. High torque is achieved by using reluctance torque in addition to magnetic torque.
2. IPM motors consume up to 30% less power compared to conventional electric motors.
3. Mechanical safety is improved as, unlike in an SPM, the magnet will not detach due to centrifugal force.
4. It can respond to high-speed motor rotation by controlling the two types of torque using vector control.