Neodymium magnet in variable frequency air conditioning

Variable frequency air conditioning is becoming the mainstream choice for environmental protection and energy conservation.

In 2023, the global sales of household air conditioners will be about 170 million units. With the impact of extreme weather and the improvement of people’s living standards, air conditioning has become an important part of daily life. However, traditional fixed-speed air conditioners often have problems such as energy waste during operation. In the context of global advocacy for energy conservation and emission reduction, variable-frequency air conditioners have gradually become the mainstream choice in the market.

The core of a variable-frequency air conditioner is its compressor, which differs from the compressor of a traditional fixed-speed air conditioner that can only operate at a fixed speed.  The compressor of a variable-frequency air conditioner can adjust its operating speed within a certain range. When the indoor temperature differs greatly from the set temperature, the compressor runs at high speed to quickly cool or heat the room; when the indoor temperature approaches the set temperature, the compressor runs at low speed to maintain a stable indoor temperature. By dynamically adjusting the operating power of the compressor, energy conservation and environmental protection are achieved.

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Neodymium magnets

The choice of magnet materials has a significant impact on the performance and efficiency of compressors. There are two main types of magnets used in compressors for variable-frequency air conditioners: ferrite permanent magnet and neodymium-iron-boron permanent magnet materials. Ferrite magnets have lower magnetic properties but are relatively inexpensive. Neodymium magnets are currently the highest magnetic performance permanent magnet materials, and are mainly used in the production of high-end variable-frequency air conditioners.

Compared to ferrite magnets, neodymium magnets have higher energy product, which means they can store more magnetic energy per unit volume. This is important for motors in compressors, as it allows the motors to be more compact while providing sufficient torque and power. Neodymium magnets also have higher coercivity, which makes them less susceptible to magnetic performance degradation due to external magnetic field interference or temperature changes, thereby improving the reliability and longevity of the compressor.

Currently, air conditioners are developing towards miniaturization. Neodymium magnets have higher magnetic efficiency, which means they require less magnetic material to generate the same magnetic field strength. This helps reduce the size and weight of compressors, thereby reducing energy consumption. In the long run, the application of ferrite in variable frequency air conditioners will gradually be replaced by high-performance neodymium magnets.

Other applications of neodymium magnets in variable frequency air conditioning

variable frequency air conditioning

Fan: In variable-frequency air conditioners, the fan motor is a key component for ensuring air circulation and heat dissipation. To achieve efficient air flow, the motor needs to generate sufficient torque and rotational speed. Traditional motor designs often rely on electromagnets to generate the required magnetic field. However, electromagnets have inherent limitations, such as high energy consumption and significant heat generation. These issues not only affect the overall efficiency of the motor, but also may lead to overheating, which can shorten its lifespan.

In order to overcome these problems, modern inverter air conditioning fan motors have begun to use neodymium magnets as the magnetic field source. The excellent magnetic properties of neodymium magnets mean that it can generate a stronger magnetic field than electromagnets in the same volume. This high-intensity magnetic field enables the motor to produce higher torque while maintaining low energy consumption. In addition, due to the excellent thermal stability of neodymium magnets, the heat generated during operation is much lower than that of electromagnets, significantly improving the reliability and longevity of the motor.

Control system: The control system is the intelligent core of the air conditioner, responsible for monitoring and adjusting various parameters of the air conditioner to ensure its efficient operation and meet the comfort needs of users.

Neodymium magnets are widely used in these sensors and switching components due to their high sensitivity and stability. For example, magnetic sensors in temperature sensors often use neodymium magnets to enhance their ability to sense temperature changes. Similarly, in switching components, the strong magnetic properties of neodymium magnets ensure reliable action of the switch, maintaining stable performance even under extreme environmental conditions. Through these applications, neodymium magnets not only improve the accuracy and reliability of frequency conversion air conditioning control systems, but also provide support for more intelligent energy-saving control.

The impact of industry development on the demand for neodymium magnets

In the period after 2010, the proportion of neodymium-iron-boron used in variable-frequency air conditioners did not continue to rise as expected, but instead showed a downward trend. The main reason for this unusual phenomenon is the change in China’s rare earth export policy, which caused a sharp rise and fall in rare earth prices in a short period of time.

Praseodymium and neodymium are key raw materials for the manufacture of neodymium magnets, and their price instability directly affects the production cost and market competitiveness of neodymium magnets.

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As the world’s leading air conditioning manufacturing country, China accounts for 80% of global air conditioning production. In 2020, China introduced stricter energy consumption standards for air conditioners, resulting in a 45% elimination rate of inverter air conditioners in the market.

Manufacturers can only effectively reduce energy consumption and meet new product energy consumption standards by using high-performance neodymium magnets. This requirement has led to a significant increase in demand for neodymium magnets. At the same time, with the gradual stabilization of rare earth supply and the increasing maturity of rare earth permanent magnet technology, neodymium magnets once again established their preferred position in the manufacture of variable frequency air conditioning compressors.

It is estimated that by 2025, the demand for neodymium magnets in the global inverter air conditioning market will reach approximately 17,000 metric tons, and the market penetration rate of rare earth inverter air conditioning will reach 70%.

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