China High Speed ​​Rail Uses World's Most Advanced Traction Technology

The schematic diagram of the CRH380A EMU loaded with the core parts of Zhuzhou Institute

Over the past 11 years, a total of 10 million trials have accumulated 150 gigabytes of data and cost 100 million yuan. China National Automotive Zhuzhou Electric Locomotive Research Institute Co., Ltd. (hereinafter referred to as “Zhouzhou Institute”) has captured the third-generation rail transportation traction technology. The magnetic synchronous motor traction system (hereinafter referred to as the “permanent-magnet traction system”) has completely independent intellectual property rights and has become a strategic weapon for the high-speed railway winning market in China.

On May 16, 2015, the permanent magnet synchronous motor used in Changsha Metro Line 1 was successfully delivered. This is the first time that permanent magnet synchronous motors have been installed in the entire column of subway vehicles to be loaded into the vehicle.

According to Ding Rongjun, academician of the Chinese Academy of Engineering and general manager of the Zhuzhou Institute, Zhuzhou has developed a 690 kW permanent magnet traction system that can be used for high-speed trains with a speed of 500 kilometers per hour. This indicates that China has become one of the few countries in the world that has mastered the technology of high-speed rail permanent magnet traction systems following Germany, Japan and France.

"China's permanent magnet traction system with its own independent intellectual property rights has stepped into the pace of industrialization. The era of permanent magnet traction in China's rail transit has finally arrived," said Ding Rongjun.

From "use of subway" to "use of high-speed rail": "Climb the Hengshan and go to Mount Everest"

The traction drive system is called “the heart of the train” in the industry, and its performance determines the power quality, energy consumption, and control characteristics of the train to a certain extent. It also affects the economy, comfort, and reliability of the train. It is energy-saving. The key to upgrade.

The first generation of traction systems for the world's rail transit vehicles was DC motor traction systems. The second generation was an AC asynchronous motor traction system that started in the 1970s. It is currently the mainstream technology.

Feng Jianghua, deputy general manager of the Zhuzhou Institute, said, “For the rail transit traction technology, the permanent magnet traction system is a revolution. Whoever has a permanent magnet traction system will have the right to speak with a high-speed rail.”

Permanent-magnet traction system is the train's power system. It is composed of two parts: converter and motor. The converter is equivalent to the heart of the train. The motor is like the muscle of the train. The motor is mainly responsible for the transmission of power to complete the conversion from electrical energy to mechanical energy. Drive the train to run smoothly.

At present, Siemens, Bombardier and other international equipment manufacturers all regard the permanent magnet traction system as their R&D direction. In this emerging field, China has not lost its starting point.

In 2003, the description of the permanent magnet traction system was first introduced into Feng Jianghua's ear. At that time, the technology was still in the theoretical research stage. However, Feng Jianghua noticed that the permanent magnet traction system will replace the AC asynchronous motor traction system and must be rapidly developed. In that year, Zhuzhou took the lead in setting up the first permanent magnet traction system R&D team in China, “starting from scratch.”

Xu Junfeng, deputy director of Zhuzhou Institute of Foundation and Platform R&D Center, stated that in the research and development phase of AC asynchronous motor traction system, China has been lagging behind China by 20 years. In the more advanced field of permanent magnet synchronization, “We are like cars without headlights. The black light gropes on the mountain road, the direction is slightly uncertain, and the consequences are not just a deviation."

“The temperature control of the motor is the biggest bottleneck of the project.” Xu Junfeng introduced that in order to prevent water, dust, iron scraps, etc. from corroding the internal permanent magnets of the motor, the motor adopts a fully-enclosed structure, but due to too high motor power and excessive heat, permanent magnet materials Under conditions of high temperature, vibration, and strong reverse magnetic fields, serious risks of irreversible demagnetization may occur. "If the train loses magnetism at high speed, the consequences are unimaginable."

Feng Jianghua recalled, “There is no information that can be used for reference, and there is also a lack of relevant equipment for research and development testing.” The Zhuzhou Institute can only “cross the river by feeling the stones”, and many of the data still rely on the more primitive stupid approach. "For example, the motor heating test is done five or six hours, the motor temperature control data on the artificial full record to keep, so to slowly accumulate." Feng Jianghua said.

Eight years after the R&D team was established, that is, at the end of 2011, the Zhuzhou Permanent Magnet Traction System was successfully installed on the Shenyang Metro Line 2 to achieve the first application in the domestic rail transit field and ended the history of the Chinese railway without permanent magnet traction system. The Zhuzhou Institute has also become the only company in China that has mastered a full set of technologies for autonomous permanent magnet traction systems. As of the end of May 2015, the Shenyang Metro Line 2 has operated 70,000 kilometers without fault.

“This time, we grabbed the top spot.” Feng Jianghua told reporters that in 2011, Zhuzhou was assigned to participate in the “863 project” of the country’s “Key High-speed Railway Key Technology and Equipment Development Key Project” and bear the high-speed train group Yongyong. Research and development of magnetic traction systems.

From "low-power" to "high-power" and from "use of subway" to "use of high-speed rail," Zhuzhou is facing new difficulties.

Li Yifeng, chief design expert of Zhuzhou Institute, told China Economic Weekly that the permanent-magnet synchronous motor used in Shenyang metro has a power of 190kW, while the motor power for a 500km/h high-speed EMU is up to 690kW, and it is always running at high speed. The stability, reliability and other aspects of the system all pose great challenges. “The challenge to motor design is like climbing a mountain and climbing to Everest.”

Despite this, Zhuzhou has completed its tasks ahead of schedule. In December 2013, Zhuzhou successfully developed a motor that could be used for 500 km/h high-speed trains. It was successfully installed at Qingdao Sifang Stock Company in October 2014.

"If it goes well, China's high-speed rail will soon be able to fully use the permanent magnet traction system, not only more energy-efficient, but also more stable and more secure." Li Yifeng said.

"Energy Saving Artifact": Increase High-speed Rail Motor Power by 60%

Ding Rongjun told the China Economic Weekly that in 2014, the traction system of the Zhuzhou Institute had a market share of 57% in the urban rail train market. In the future, the permanent magnet traction system will gradually replace the asynchronous motor system.

Liu Kean, deputy general manager and chief engineer of Zhuzhou Electric Co., Ltd., said: "Efficient and energy-saving is the most prominent advantage of permanent magnet traction systems."

The data shows that the 690kW permanent magnet synchronous motor developed by Zhuzhou has 60% more power than the current mainstream asynchronous motor and the motor loss is reduced by 70%.

According to the actual operation data of Shenyang Metro Line 2, Liu Kean calculated a bill: A subway can save energy by 4 million yuan each year. “This is profit. Which unit will not use it?”

According to Liu Kean’s industry analysis report, around 2020, about 100 urban rail transit lines will be built nationwide. If 60% of newly-built lines use permanent magnetic traction systems, the expected output value will reach 10 billion yuan, and the annual energy consumption of the new line will save 240 million yuan.

The permanent magnet system also shows a strong alternative advantage in the central air conditioning field. The central air conditioner based on a permanent magnet variable frequency drive system can achieve energy savings of 40%. A 240kW central air conditioner, if operated for 4 months each year, can save at least 145,200 kWh of electricity a year. According to the calculation of 40,000 central air conditioners nationwide, electricity consumption of 4.6 billion kWh will be saved in one year, and 460,000 tons of carbon dioxide will be emitted less.

Since the launch of R&D in 2009, Zhuzhou has successfully developed the world's first central commercial air-conditioning permanent magnet high-speed direct drive system, becoming the only supplier of central air-conditioning permanent magnet drive systems at home and abroad. As of the end of April 2015, the permanent magnet system of Zhuzhou has applied more than 400 sets of central air conditioners. At the China Refrigeration Show in April this year, Gree Electric put central air-conditioning with permanent-magnet synchronous frequency conversion heat pump centrifuges as its high-end products on the market.

The high efficiency and energy saving of the permanent magnet traction system enables Zhuzhou to occupy a high point of market competition in areas such as electric vehicles, wind power generation, and 100% low-floor modern trams.

Feng Jianghua said that the development and industrial application of permanent magnet traction system is still in its infancy. “In the future, Zhuzhou will continue to deepen and refine technology development on the one hand, and will continue to expand the application of permanent magnet traction technology on the other. Field, achieve overall layout and continuous leadership."

Expert Reviews

Academician Liu Youmei of the Chinese Academy of Engineering:

Permanent Magnet Synchronous Traction System Is the Model of High-speed Railway Technology Upgrade in China

The electric traction system technology of the world's rail transit vehicles has undergone development from the “DC drive traction system” to the “AC drive traction system” and is currently being developed from “induction asynchronous drive” to “permanent magnet synchronous drive”. Due to its significant advantages of high efficiency and high power density, the permanent magnet synchronous traction system represents the current technological development trend of advocating energy conservation, emission reduction and environmental protection. It has become a technological hotspot for large-scale countries to compete for research and is unable to spend money. The core technology.

China National Chengzhou Zhuzhou Electric Locomotive Research Institute successfully developed a permanent magnet synchronous traction system for high-speed trains, making China one of the few countries in the world to master high-speed rail permanent magnet traction system technology. The motor rated efficiency of the permanent magnet synchronous traction system reaches more than 98%, reducing the motor loss to the original one-third, significantly reducing the traction energy consumption of high-speed trains. In the context of China's increasingly tense energy and the urgent need for "green traffic" in the society, the permanent magnet synchronous traction system has become a model for upgrading high-speed railway technology in China.

In order to catch up with the developed countries’ technological level as soon as possible, we actively raised our goals in the development process.

Zhuzhou Electric Locomotive Research Institute Co., Ltd. Deputy General Manager Feng Jianghua

Technological innovation is the pillar on which companies survive and the driving force for lasting development. In 2003, we started the basic research of permanent magnet synchronous traction system. At that time, the permanent magnet technology was still in its infancy in foreign countries. The technology was completely confidential and the technology was strictly blocked outside the country. We can only start from scratch, touch the stones and cross the river, carry out a large number of theoretical analysis, simulation research and three-dimensional virtual design, etc. We have experienced millions of ground tests and accumulated hundreds of G hard disk data. We successfully developed in 2011. The first permanent magnet synchronous traction system for rail transit in China was successfully installed on the Shenyang Metro Line 2 train. This is also the first application of the permanent magnet system in the domestic rail transit field.

In the same year of the Shenyang test, we received the task of developing a 600kW permanent magnet synchronous traction system for high-speed EMUs under the national "863 Program." In order to catch up with the technological level of the developed countries as soon as possible, after receiving the mission, we have raised the target of development to 690 kW internally. The three years of sticking and paying, in return for the joy of success.

The quality of the traction system determines the technical level of the train. The high-speed EMU 690kW permanent magnet synchronous traction system we developed has enabled China’s high-speed railway to have the most advanced traction technology in the world, which has effectively enhanced the technical level of China’s high-speed railway and once again demonstrated to the world that China’s high-speed railway is fully equipped with independent innovation. Technical capabilities.

More crucially, permanent magnet drive technology has not only triggered a technological revolution in the field of rail transit, but also is the core technology of new energy vehicles, ultra-high-speed permanent magnet drive centrifugal commercial air-conditioning, wind power and other fields, and is the cornerstone of our high-end equipment technology progress. . (Reporter Cao Chang trainee reporter Li Yonghua)

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