Direct Drive PMAC Motor Variable Speed IP54 IP55 3 Phase Permanent Synchronous Motor

There are many types of permanent magnet synchronous motors, which can be divided into sine wave permanent magnet synchronous motors and trapezoidal wave permanent magnet synchronous motors according to the waveform of the stator winding induced electromotive force. In the structure of touch screen maintenance in the composition of machine tool equipment, the stator of the sine wave permanent magnet synchronous motor used is composed of three-phase windings and iron cores. The armature windings are often connected in a Y-shape and short-distance distributed windings are used: the air gap field is designed as a sine wave, to generate a sine wave counter electromotive force; the rotor uses permanent magnets instead of electric excitation.

1. Motor control method

At present, there are mainly two control methods for three-phase synchronous motors, one is another control type (also known as frequency open-loop control); the other is a self-control type (also known as frequency closed-loop control). The other control method mainly adjusts the speed of the rotor by independently controlling the frequency of the N#I-part power supply. It does not need to know the position information of the rotor, and an open-loop control scheme with a constant voltage-frequency ratio is often used. The self-controlled permanent magnet synchronous motor also adjusts the rotor speed by changing the frequency of the external power supply. Unlike the other control type, the change in the frequency of the external power supply is related to the position information of the rotor. The higher the rotor speed, the higher the stator energization frequency. The rotor speed is adjusted by changing the frequency of the applied voltage (or current) to the stator winding.

Because the self-controlled synchronous motor does not have the out-of-step and oscillation problems of the other-controlled synchronous motor, and the permanent magnet of the permanent magnet synchronous motor does not have brushes and commutators, which reduces the volume and quality of the rotor and improves the Response speed and speed range of the system, so we use a self-controlled AC permanent magnet synchronous motor. When the three-phase symmetrical power supply is added to the three-phase symmetrical winding, a synchronous rotating stator magnetic field will naturally be generated. The rotational speed of the synchronous motor rotor is strictly synchronized with the frequency of the external power supply and has nothing to do with the size of the load.

2. The principle of PMSM motor

PMSM stands for Permanent Magnet Synchronous Motor. The principle of operation of a PMSM motor is based on the interaction between the magnetic fields of a permanent magnet rotor and the stator winding currents.

The stator of the PMSM motor has multiple windings that are energized by a three-phase AC power source. The energized windings produce a rotating magnetic field that interacts with the permanent magnets on the rotor, causing it to rotate. The stator winding currents must be synchronized with the rotor position to maintain torque production.

The PMSM motor is a synchronous motor, which means that the rotor rotates at the same frequency as the stator field. The speed of the motor is directly proportional to the frequency of the AC power source and the number of poles in the stator.

The PMSM motor is a highly efficient and precise motor that is widely used in various applications, such as electric vehicles, robotics, and industrial automation.

3. The structure of the PMAC motor

A three-phase PMAC (Permanent Magnet AC) motor typically consists of two main parts: the stator and the rotor.

The stator is the stationary part of the motor and contains the three-phase winding that is connected to an AC power source. The stator winding produces a rotating magnetic field, which interacts with the permanent magnets on the rotor to produce torque and rotation.

The rotor is the rotating part of the motor and contains permanent magnets that produce a constant magnetic field. The permanent magnets are typically arranged in a radial or axial orientation, depending on the design of the motor.

The rotor is surrounded by the stator winding, which is usually placed in slots on the inner surface of the stator core. The stator core is made up of laminated steel sheets that are stacked together to reduce magnetic losses.

The motor also includes a shaft, which is connected to the rotor and supports the load being driven by the motor. The bearings support the shaft and allow it to rotate smoothly.

Overall, the three-phase PMAC motor structure is simple, efficient, and reliable, making it suitable for a wide range of industrial and commercial applications.

4. Benefits of PMSM motors:

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High efficiency

This is particularly true at lower speeds. The permanent magnet motor does not require current to be supplied to its rotor to generate the rotor field, therefore eliminating the rotor losses almost completely. When compared to induction or reluctance motors it also requires lower currents on the stator and has a bigger power factor, leading to smaller current ratings on the controller, and increasing the overall drive system efficiency.

Driving lower speeds at higher efficiency than an induction motor might delete the requirement of a speed-reduction transmission, taking the complexity out of the mechanical arrangement.

Constant torque

This type of motor can generate constant torque and maintain full torque at low speeds.

Size

The smaller size, lighter weight, and less coil provide a higher power density.

Cost-effective

With the absence of brushes, there are reduced maintenance costs.

Minimal heat

In PMSM the heat is generated on the stator coils and there are no brushes and only minimal heat generated on the rotor, facilitating the cooling of the motor. As they run cooler than induction motors, the motor's reliability and lifespan are increased.

Speed range

This type of motor can have a wide speed range with the use of Field Weakening and can adopt the maximum torque/current (MTPA) control strategy during constant torque operation.

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