In depth interpretation of key technologies for oil cooled permanent magnet speed controllers to assist carbon neutrality

Peaking carbon emissions and achieving carbon neutrality are goals set by China as a whole, both internationally and domestically. They are solemn commitments made to the international community after considering ecological civilization and economic development, and are of great significance for global efforts to address climate change and high-quality economic development in China. Industries with high energy consumption such as electric heating, petrochemicals, steel, and metallurgy have always been major carbon emitters in China. In terms of electricity consumption, their electricity consumption accounts for 68.2% of the country's total electricity consumption. How to address high energy consumption?

According to statistics on the implementation of national projects benefiting the people, industrial motors account for about 75% of the total industrial electricity consumption. After efforts, the market share of high-efficiency motors in China has increased from less than 5% to around 25%. However, it should be noted that the efficiency of over 70% of motor products is still 2% to 5% lower than the advanced level abroad, and the overall market share of high-efficiency motors is still relatively low. In actual operation, due to unreasonable system matching, long-term low load operation of equipment, and outdated transmission and speed regulation methods, the actual operating efficiency of the motor system is 10% to 20% lower than the advanced level abroad, and the gap is even greater.

Permanent magnet speed regulator is a revolutionary transmission device that transmits torque through an air gap. There is no need for mechanical connection between the motor and the load device shaft. When the motor rotates, it drives the active rotor of the conductor to cut magnetic lines in the strong magnetic field generated by the disk driven rotor equipped with strong rare earth magnets. As a result, eddy currents (Eddy Current) are generated in the disk, which induce a magnetic field on the active rotor of the conductor. The magnetic attraction and repulsion between the induced magnetic field and the permanent magnetic field pull the driven rotor, thereby achieving torque transmission between the motor and the load

The motor is connected to the active rotor at a constant speed. By adjusting the size of the air gap (distance) between the driven rotor and the active rotor, the magnetic field at the position of the driven rotor can be adjusted. The smaller the air gap, the stronger the magnetic field at the position of the active rotor, and the stronger the induced magnetic field generated by its high-speed rotation, resulting in a larger torque and higher load speed. On the contrary, the larger the air gap, the smaller the magnetic field at the position of the active rotor, the smaller the induced magnetic field generated by its high-speed rotation, the smaller the torque generated, and the lower the load speed.

The horizontal oil cooled permanent magnet governor system is an additional three parts installed outside the oil cooled dedicated permanent magnet governor device for cooling and cooling during equipment operation. The overall composition is: oil cooled permanent magnet governor+permanent magnet distribution box+thin oil station+thin oil station terminal box

The oil cooled permanent magnet governor consists of an outer sleeve, a permanent magnet equipment body, an electric actuator, and other components. The permanent magnet equipment body is connected to the load shaft by a high-precision permanent magnet rotor assembly (containing high-strength permanent magnets), and to the motor shaft by a composite conductor rotor. There is no physical (mechanical) connection between the outer rotor and the inner rotor. The entire permanent magnet equipment is installed inside a sealed outer sleeve, and during operation, it is supplied with oil by a lubrication station to spray on the main body of the permanent magnet equipment for cooling and lubrication.

Effective energy saving:

By using permanent magnet speed regulator technology, continuous control of flow and/or pressure can be achieved by adjusting the air gap, replacing the valves or air dampers that control flow and/or pressure in the original system. The speed of the fan or water pump can be adjusted while keeping the motor speed constant.

The permanent magnet transmission technology mainly transmits the torque output of the torque motor:

The torque output by the motor is equal to the torque required by the load equipment;

Centrifugal loads such as fans and pumps follow the law of similarity, where torque changes are proportional to the square of speed changes, i.e. Tl/T2=(N1/N2) 2; Power=T × W (torque × speed), so the output power of the motor is proportional to the square of the speed ratio of the load device, that is, P1/P2=(N1/N2) 2.

Vibration reduction:

As shown in the figure, the torque transmission without mechanical connection solves the problems of vibration caused by the coupling and excessive load on the motor bearings.

Soft start with buffering

Reducing the starting impulse current of the motor, minimizing torsional vibration, avoiding bearing sleeve running of the motor, and reducing the bearing load of the motor. At the same time, there is a 2-4% speed reduction *, which can further reduce the operating current of the motor and thus lower the bearing temperature.

Allow for larger installation alignment errors

Greatly simplifying the installation and debugging process, saving time.

Long service life

联轴器和永磁耦合器输出功率对比图（来源于沃弗实验室）

At present, the Wofer oil cooled permanent magnet speed governor has been applied to the energy-saving technology transformation of high-power motors in many large energy intensive industrial and mining enterprises, such as middling coal Datong Energy Power Plant, Guodian Longshan Power Plant, Guodian Tai'an Power Plant, Shenhua Guohua Mengjin Power Plant, Datang Faer Power Plant, Guodian Zhenjiang Dagang Power Plant, Nanjing Iron and Steel Group No. 3 Steelmaking Plant, CSIC, Xiangtan Iron and Steel, Yunnan Aluminum, etc. The equipment is in good operation. Taking the transformation project of Guodian Zhenjiang Dagang Thermal Power Plant as an example, the horizontal oil cooled permanent magnet speed governor is used to regulate the induced draft fan, saving a total power of 2.2458 million kW • h per year, equivalent to an annual saving of 729 standard coal 88t, carbon dioxide emission reduction 2023.6t/a *.

2021 is the starting year of the 14th Five Year Plan and a crucial year for the development of the post pandemic era. The manufacturing industry is transitioning from the mid to low end to the mid to high end, from being large and specialized to being refined, and from production-oriented manufacturing to service-oriented manufacturing. The task of achieving sustainable economic and social development while achieving carbon peak and carbon neutrality is extremely arduous and the challenges are enormous. To make a difference in this unprecedented transformation, Wolfe Permanent Magnet strives to achieve significant breakthroughs in new theories, discoveries, and technologies in the field of permanent magnet transmission, making a real contribution to carbon peaking and carbon neutrality.

Notes:

1. Electricity accounts for 68.2% of the national electricity consumption, and the data is compiled by China Electricity Council and Zhiyan Consulting;

2. 2-4% deceleration, data sourced from Wover Laboratory.

3. Power saving rate: 20%~50%; The total annual energy savings are 2.2458 million kW • h, equivalent to an annual savings of 729.88 tons of standard coal and a reduction of 2023.6 tons of carbon dioxide emissions. The data is sourced from the 2020 National Industrial Energy saving Technology Application Guidelines and Cases (2020),

Link: https://www.miit.gov.cn/jgsj/jns/gzdt/art/2020/art_eceaa82a7ce84a54bc06261da5c11de9.html