Magnet for PMSM

Horizon Magnetics has been focusing on the development and production of a high-end series of PMSM magnets to provide a magnet solution with high magnetic energy product, excellent temperature stability, and long service life.

What Are Permanent Magnet Synchronous Motors:

Permanent magnet synchronous motors (PMSM) are advanced AC electric motors consisting of a stator, and a rotor which is connected to the output shaft. The permanent magnet AC motors typically use Neodymium magnets, which are embedded in the rotor to create torque garnered by electromagnetism. The rotation speed of a PMSM is synchronized with the electric frequency of the alternating current. PMSM motors are an excellent choice for a range of motion control applications.

Advantages of PMSM Motors:

1. High efficiency. This is particularly true at lower speeds. No current is required to supply to the rotor to generate the rotor field, so it’s almost complete to eliminate the rotor losses.

2. Constant torque. The PMSM motors can generate constant torque and maintain full torque at low speeds.

3. High power density: The smaller size, lighter weight and fewer coils provide a higher power density. 

4. Cost-effective: Simple structure with the absence of brushes and reducers reduces maintenance costs.

5. Long service life, safe and reliable: The PMSM Motors generate minimum heat on the rotor and don’t need brushes, so the motors’ reliability and lifespan is increased.

6. Low noise: No windings on the rotor produce electromagnetic noise during operation, its speed synchronized with the power frequency does not generate vibration noise, the simple structure without commutators and brushes reduces the generation of noise.

Disadvantages of PMSM Motors:

1. High initial cost: PMSM motors have higher requirement about materials including Neodymium magnets and production processes, resulting in relatively higher processing costs. Moreover, permanent magnet synchronous motors require specialized inverters to achieve frequency regulation and control, and the cost of inverters is relatively high.

2. Difficult to start: PMSM motors need some method like external DC source to bring them up to synchronous speed when they are initially turned on since they cannot start on their own.

Wide Applications of PMSM Motors:

1. High precision motion control systems: Applications requiring high-precision control, such as in robotics, CNC machining, and medical equipment, benefit from the use of PMSMs due to their precise speed and position control capabilities.

2. Pump and Fan Systems: PMSMs are used in various pump and fan applications, like water pumps, vacuum pumps, and industrial fans, due to their ability to operate efficiently at different speeds and loads.

3. HVAC systems: PMSM motors are employed in heating, ventilation, and air conditioning (HVAC) systems, including fans and pumps, due to their energy efficiency and ability to operate at variable speeds, matching the load requirements accurately.

4. Elevator or lifts: Permanent magnet synchronous gearless traction machines are used in the elevators thanks to their ability to operate efficiently with low vibration, noise, maintenance and expense.

5. Industrial automation: Permanent magnet synchronous motors find extensive use in industrial applications, such as robotics, conveyors, and various machinery used in manufacturing processes. Their precise speed control, low vibration, high torque and efficiency make them suitable for different automation tasks.

6. Electric vehicles: PMSM motors are commonly used in electric vehicles due to their high efficiency, compact size, and ability to provide high torque at low speeds.

7. Consumer appliances: Certain household appliances like washing machines, refrigerators, and dishwashers also use PMSMs for their energy efficiency, reduced noise levels, and improved performance.

8. Aerospace: Permanent magnet synchronous machines are employed in aerospace systems, including electric propulsion systems in aircraft and satellites, owing to their lightweight design, high power density, and efficiency.

Why Horizon Magnetics Magnets for PMSM Motors Optimizes Quality of Electric Motors:

Because PMSM motors have applications in a wide of areas with various environments, selecting the right type of AC motor magnets based on the specific application and environmental conditions is the key to optimizing electric motor performance. To adapt to the working environment, we have been devoting ourselves to developing and manufacturing NdFeB rare earth magnets for PMSM motors with following characteristics:

1. Wide range of magnetic properties: Electric motors mainly use Neodymium magnet grades of M, H, SH, UH, EH, and AH with maximum energy product ranging from 28 MGOe to 55 MGOe.

2. Various shapes and sizes: PMSM motor magnets are customized and available with various shapes like block, ring, segment, loaf and wedge along with appropriate size to meet the demands of a unique motor design so that magnetic flux may be optimally distributed to enhance efficiency and working stability.

3. Extreme effect: Extreme high magnetic energy product magnets like N54H, N45UH and N42EH Higher are helpful to attain higher torque density to enhance electric motor performance, particularly in those applications requiring compact and powerful motors. Intrinsic coercivity Hcj high to >35kOe (>2785 kA/m) increases magnets demagnetizing resistance. Neodymium magnets with high remanence (Br) and coercivity (Hc) are ideal for high-performance motors. Reversible temperature coefficients of PMSM magnets low to α(Br)< -0.1%/ºC and β(Hcj)< -0.5%/ºC ensures the AC electric motors to work with good stability under varying temperature conditions.

4. Consistency of magnetic properties: Control better consistency between magnets so as to reduce vibration or noise during electric motor working process.

5. Corrosion resistance: Coatings such as Nickel, Epoxy, or combinations protect the Neodymium magnets from corrosion, especially in electric motors exposed to harsh environments. Optimization of material composition and production technology improves the weight loss of Neodymium magnet material low to 2~5mg/cm2 in HAST testing condition: 130ºC, 95% RH, 2.7 ATM, 20 days which increases magnet corrosion resistance and then service life of the permanent magnet synchronous motors.