Advantages of Permanent Magnet Synchronous Motors

PMSMs carve a niche for themselves within the growing industrial motor technologies due to their higher efficiency and performance. To begin to understand the advantages of PMSMs, it would be important to first consider the common problems that occur during traditional motor use and how PMSMs overcome those issues.

I. Major Issues in Motor Utilization

Power Loss in Motors Concept

Motors convert input electrical energy to magnetic and then into mechanical energy to deliver an output. This process of energy conversion, while vital for operation, inherently creates several kinds of loss; these include:

1.Energy Conversion Efficiency of Motors: During operation, motors suffer circuit, magnetic, mechanical, and stray losses; all these are converted into heat. All these losses bring down the overall efficiency of motors.

2. Power Factor of Motors:In the case of asynchronous motors, the excitation current formed in the stator does not do any useful work but results in line losses and heating. This gives rise to a type of loss known as “power factor loss.”

Problems of Motor Utilization

1. High Power Consumption Motors:Most of the conventional motors operate on low power efficiency with huge energy losses, resulting in excessive temperature generation and increase in workplace temperature.

2.Over-sized Motors for Small Loads: In order to provide greater starting torque, motors are often over-specified and hence become uneconomical. When the load is small the efficiency falls off sharply and the power factor deteriorates.

Selection of Motors

In selecting motors for energy-saving retrofitted or new custom-designed equipment, the following guidelines can reduce these problems:

1.Selection of High-Efficiency Motors: Use high-efficiency motors of first or second-level efficiency to replace lower-efficiency motors that are being phased out.

2. Reasonable Power Selection:On-site testing shall be taken to determine the appropriate motor size based on real-world performance data.
3. Appropriate Control Mode:Avoid high-energy consumption control methods such as autotransformer or star-delta starting. VFD control avoids power surges at startup, reducing mechanical and electrical shock during startup.

PMSM Advantages

Now that the disadvantages of the conventional motor systems have been discussed, special merits of Permanent Magnet Synchronous Motors are focused on.

Concept of Synchronous Motors

PMSMs are AC motors in which permanent magnets are inserted into a steel rotor, and windings are attached to the stator. When a three-phase current flows through the stator coils, it generates a rotating magnetic field that turns the rotor. PMSM stands for synchronous because, during unchanging operation, the speed of rotor rotation is at a synchronized rate to the rotation of the magnetic field.

PMSMs have a rotor of rare-earth permanent magnetic material that provides a constant magnetic field. This constant magnetic field interacts with the rotating magnetic field of the stator, which then makes the rotor run in sync with the speed of the stator. Therefore, the rotor is always at synchronous speed, and this contributes to high efficiency and accuracy for the motor.

Key Advantages of PMSMs

High Efficiency

1.Reduced Losses: The compact magnetic circuit and smaller windings reduce copper and iron losses, which directly enhance efficiency.

2.No Induced Current in Rotor: The use of rare-earth magnets on the rotor eliminates induced currents, hence no rotor resistance and hysteresis losses.

3. High Power Factor:Since the stator current does not include the excitation current, PMSMs provide higher power factor that reduces stator current and copper losses, hence making them more efficient.

High Power Factor

1. Resistive Load:Absence of induced currents for excitation results in the stator presenting a resistive load pulling the power factor near.
2. Grid Advantages:PMSMs, by reducing stator current, improve not only efficiency but also grid power quality, reduce transmission losses, and reduce the requirement for huge transmission capacity, thus saving infrastructure cost.

High Starting Torque

Economical in Heavy-Duty Applications: PMSMs give high starting torque, hence very suitable for applications such as twisting machines. This facilitates smaller capacity motors for higher capacity, less efficient ones, thus reducing initial investments and improving efficiency.

Low Temperature Rise

Heat Management Efficiency: Much less heat generation by PMSMs, as compared to conventional motors due to the absence of copper loss in the rotor and almost negligible reactive current in the stator windings hence reduced temperature rise and longer motor life.

Improved Performance Under Different Load Conditions

1. Constant Efficiency:PMSMs have a high efficiency for a wide range of loads, whereas asynchronous motors exhibit considerable deterioration in performance at low loads. This makes them effective in applications where the load demand fluctuates, such as in motors that have large starting loads and small operational loads.

2. Long-Term Savings:When a Y-series motor runs at 60% of the load, the drop in efficiency is 15%, while its performance indicators decline by 40%. Contrarily, at a load as low as 20%, PMSMs still keep up more than 80% of their performance. Thus, when using PMSMs, this guarantees huge long-term energy savings.

ENNENG: A Leader in PMSM Innovation

Qingdao Enneng Motor Co., Ltd. (ENNENG) is one of China leading permanent magnet motor provider. As one of the “Hundred Innovative Enterprises” of Qingdao in 2018 and a member of Qingdao Motor Industry Association. ENNENG’s solutions guarantee unparalleled performance and energy efficiency in various industrial applications.

Energy-Efficient Solution: ENNENG’s PMSMs are designed with advanced NdFeB permanent magnets and achieve IE4-level efficiency, thereby offering 5-10% energy savings over conventional motor designs. This makes them perfect for industries in line with sustainability, such as automotive, mining, and water treatment.

Custom Applications: ENNENG can create a PMSM for an exact application-from high torque applications of heavy machinery down to variable speed applications in robotics and automation-and realize up to 40% energy savings, especially for rubber tire manufacturing.

Industry Experience: With very broad experience in manifold industries such as oil and gas, industrial machinery, and textiles, among others, your business partner is ENNENG for the most high-tech applications of PMMS.

Conclusion

PMSMs offer an enormous amount of advantages, from their efficiency to high torque, making them one of the necessary drives in fields starting from simple electric vehicles up to automation and energy generation. Further, this makes them increasingly viable due to noiseless operation, low maintenance requirements, and the least environmental effects. In these cases, on the path to optimizing operations for enterprises, ENNENG provides the most advanced solutions based on PMSM for excellent performance, energy efficiency, and ensuring long-term cost savings.