Analysis of the Application Situation of Switched Reluctance Motor in Domestic Market
The modern switched reluctance motor was born in the UK in the 1980s. It is relatively young in the motor type. It has developed rapidly in the past 30 years, first of all thanks to its structure: there are no slip rings, windings and permanent magnets on the rotor of the motor. There are concentrated windings on the top, there is no phase jumper, so the motor structure is relatively simple, easy to maintain and repair, the speed running range is wide, it is easy to achieve 15000r / min. Of course, the shortcomings of the switched reluctance motor are also obvious. Due to the double salient pole structure, torque ripple and noise are inevitable, which is an obstacle that is difficult to overcome by the switched reluctance motor.
The data show that the efficiency of the first generation of switched reluctance motors developed by our country in 1985 is lower than that of high-efficiency variable frequency motors, but only a few years later, the efficiency of the second generation of switched reluctance motors has been developed. Fully exceeds the high efficiency variable frequency motor. The inherent torque ripple of the switched reluctance motor and the large noise are also effectively suppressed with the development of the motor design technology. For example, the servo-switched reluctance motor developed by SRD Ltd. of the UK, the torque ripple is only It is 0.05%.
Some scholars have concluded that the application development of switched reluctance motors should be combined with the field, mainly considering the following five conditions:
(1) There is energy-saving need, energy saving 10-30% is the normal range, and the user's electricity cost in 1-3 years can earn back the transformation cost;
(2) There is a need for frequent positive and negative reversal, simplifying the mechanical structure;
(3) There is a short-term overload demand, such as 5 times starting torque or 3 times rated speed instantaneous overload;
(4) There is a wide range of shifting requirements, such as 10-150% speed regulation requirements;
(5) The requirements for noise and vibration are not strict.
On the basis of satisfying Article 5, if other 1-2 conditions can be met, a switched reluctance motor can be considered for better performance.
The earliest domestic industrialization of switched reluctance motors should be Beijing China Textile Co., Ltd. Unfortunately, this company has gone from bad to worse since 2012 until it was acquired by the Japanese. Beijing Zhongfang was mainly used in mining and oilfield industries in the early days, and promoted in the name of energy-saving renovation. Since the coal mine was a golden age ten years ago, the profit of the motor applied to the coal mine was also high, which led to Beijing Zhongfang Le not thinking about it, and did not open up other industries. With the sluggish coal industry, Beijing Zhongfang’s sales are getting smaller and smaller. Until it is acquired. At present, Beijing Zhongfang is also promoting the oilfield machinery. I don't know if it is because of the strategic layout of Nideco in Japan, so that the energy of Beijing Zhongfang is put on the electric car, and the performance in other occasions is average.
Since 2011, Shandong Kehui Electric has become the leader of the domestic switched reluctance motor enterprises. It is the first to propose the application of switched reluctance motors to electric screw presses at home and abroad, and currently accounts for about 70% of the national market share. According to media reports, Kehui Electric has been developing switch reluctance motors since 2002. It was initially promoted in wind turbines, gantry planes, etc., and the results were not good. Later, it was combined with universities to discuss the application of electric presses and persisted in investing for 10 years. Only after returning, the private enterprise is really not easy to do the real economy.
In recent years, more and more companies have developed R&D switches, and companies in Shenzhen, Hunan, Xi'an, Chengdu, Hangzhou, Nanjing and other places have launched products. For the switch reluctance practitioners, this is good news. It will only make the market smaller and smaller, and the market will be bigger. However, due to the short development time, the switched reluctance motor industry is still a niche industry. The domestic market for switched reluctance motors is mainly
(1) Forging machinery: At present, the most successful application of switched reluctance motor, no one, this occasion fully meets the above five conditions, overload requirements, forward and reverse, wide speed range, energy saving and other advantages , completely ignore the shortcomings of switched reluctance motors: noise, vibration and torque ripple. In the circle of switched reluctance motor enterprises, there is a saying that the forging is the best in the world. Shandong Kehui Company has achieved the first place in the country in recent years, and it is inseparable from its early accurate market development and positioning.
(2)Textile machinery: In this application, we must first thank the foreigners. The domestic mainstream imported textile machinery PICANOL has taken the lead in adopting the switched reluctance motor, which makes the domestic looms manufacturers naturally recognize the switched reluctance motor since 2009. After that, the switched reluctance motor gradually took its place in rapier looms and towel looms. When the textile application meets the conditions of 1, 3, and 5 mentioned above, energy saving and quick start (3 rotations of the motor can reach the rated speed from zero speed), and there is no requirement for vibration and noise. The switch reluctance motor used in foreign looms is four-phase 8/6 pole, and the domestic early stage is three-phase 12/8 pole. At present, four-phase motors are also introduced in China, and it is possible to gradually phase out the three-phase 12/ in the textile industry. 8 structure. It is very strange that Beijing China Textile Co., Ltd. was born in the Textile Research Institute. However, Beijing Zhongfang's switched reluctance motor has never been promoted in textile machinery. On the contrary, Shandong, Shenzhen, Hangzhou and other companies have promoted well in the textile industry.
(3) Oilfields and coal mines: Energy and environmental protection have always been the strategic layout of the country. The use of switched reluctance motors in pumping units, coal mine conveyor belts and other occasions can save more than 30% energy. The effect is still very obvious. In recent years, Shengli Oilfield and Zhongyuan Oilfield Changqing Oilfield has reform projects, and the overall requirements to meet the transformation requirements, but the oilfield market is the location of state-owned enterprises, ... you know, it is difficult to achieve large-scale promotion. As for the coal mine, for Beijing Zhongfang, Cheng Xiao also lost Xiao He. These years are the off-season of coal, and it is difficult to scale up.
(4) Small household appliances: This aspect mainly focuses on the application of high-speed switched reluctance motors. Foreign vacuum cleaners, cooking machines, broken machines, washing machines, etc. have applied switched reluctance motors in large quantities, and their performance has been significantly improved. Wide, however, there are only a few news in the country that mention the development of prototypes, and there has not been a large-scale application. Perhaps the cost price is the main bottleneck restricting the promotion of these occasions.
(5) Electric vehicles: For switched reluctance motors, mentioning electric vehicle applications may be a bitter tear. Regardless of domestic or foreign, the earliest prototypes of switched reluctance motors are developed for electric vehicles. They are optimistic about the large starting torque of switched reluctance motors and the advantages of good acceleration performance are very suitable for electric vehicle applications. Domestic Huazhong University of Science and Technology and Beijing China Textile Co., Ltd. jointly installed 20 switched reluctance motors for hybrid buses in Wuhan, and conducted long-term operation tests, which is quite effective. However, due to noise, power density and other issues, the electric vehicle market has been basically occupied by permanent magnet motors in recent years, which is also related to the low price of domestic permanent magnets. In the long run, permanent magnets are non-renewable resources and cannot support the huge market demand for electric vehicles. Switched reluctance motor practitioners should continue to dig deeper and wait for the flowers to bloom.
(6) Other occasions: In recent years, the number of enterprises producing switch reluctance motors has gradually increased. Each company has also made great achievements in various places. It has been tried on different occasions. The simplest ones are energy-saving renovations such as fans and pumps. Others such as ball mills, sliding doors, shears, starter/generators, injection molding machines, etc. have also achieved certain results, but the scale of use in these occasions is still small, and whether it can be promoted throughout the industry in the future needs to continue to observe. .
Summary: Switched reluctance motor is a new type of speed control system developed in the past 30 years. Its advantages and disadvantages are also obvious. The switch reluctance motor proposed by some manufacturers to attract investment will replace the general asynchronous motor (or It is not realistic to call the innovation plan. How to combine the characteristics of the field application, give full play to the advantages of the switched reluctance motor, and avoid or reduce the disadvantages caused by its shortcomings, is the direction that scientific research workers should make steady efforts.
