"The flywheel energy storage regenerative braking energy recovery system uses a variable frequency and variable voltage drive method in urban rail and subway transportation. When the subway is braking, electric braking is first performed to convert kinetic energy into electrical energy. Part of the energy is used by adjacent In addition to vehicle absorption. If the energy cannot be effectively absorbed, it will lead to an increase in the DC power of the traction network and affect the operation of the system. Therefore, the traditional solution is to use a braking resistor. This method wastes electric energy and is not energy-saving or environmentally friendly. . If a flywheel energy storage device is used to recycle energy, the electrical energy that can be saved can account for about 15%-17% of the traction power."

　　——Jiang Weiliang, Director of Physical Energy Storage Technology Research Institute of Shenyang Microcontrol New Energy Technology Co., Ltd.

　　Focusing on "double innovation in technology application, a new starting point for large-scale energy storage", it will accurately connect the global energy storage market and the global energy storage market in multiple dimensions by organizing keynote speeches, exhibitions, innovation competitions, special seminars, project inspections, new product releases, technical exchanges and other activities. The application helps Chinese energy storage companies integrate with international standards and builds a communication and interaction platform for energy storage companies with policy makers, planners, grid managers, power companies, and energy service providers. From May 18 to 20, 2019, the Zhongguancun Energy Storage Industry Technology Alliance and the Institute of Engineering Thermophysics of the Chinese Academy of Sciences held the "ESIE 2019 Energy Storage International Summit and Exhibition", and the entire event was broadcast live on the Polaris Energy Storage Network and the Electric Power Toutiao APP.

　　Jiang Weiliang, Director of Physical Energy Storage Technology Research Institute of Shenyang Microcontrol New Energy Technology Co., Ltd.

　　Good afternoon, distinguished guests! I am Jiang Weiliang from Microcontrol New Energy. I am very honored to be able to speak at this conference. My report is divided into four aspects:

　　Part One: Company Profile. First, let’s introduce VYCON, which was founded in 2003 and is headquartered in Los Angeles, California, USA. Shenyang Microcontrol New Energy Company has reached a comprehensive and exclusive strategic partnership with VYCON, and has all the technical capabilities and the right to use the VYCON brand. It is headquartered in Shenyang YYW-German Industrial Park, with an area of 100 acres. It has a R&D center in Shenzhen and is independent. R&D capabilities and production capabilities. It has applied for 16 invention patents, two utility model patents, two appearance designs, and 6 software copyrights. This is a magnetic levitation flywheel energy storage production line, and this is related intellectual property.

　　The second part introduces the key technology of magnetic levitation flywheel energy storage. This is a cross-sectional view of flywheel energy storage. The main part includes permanent magnet synchronous electrode technology, which can be used as both a generator and an engine technology to achieve two-way conversion of electrical energy and kinetic energy. The flywheel achieves the main storage of kinetic energy, and the bearing system plays a role in support and protection.

　　The flywheel electrode emits a three-way variable frequency alternating current. The power converter realizes two-way conversion of DC and AC to realize variable frequency drive. Working principle: In charging mode, the externally input electric energy drives the rotor to rotate through the motor, driving the flywheel to accelerate rotation. To convert electrical energy into kinetic energy and store it, the process of discharge is the opposite. The technology of flywheel energy storage is developing in the direction of continuously increasing energy density and reducing its own losses.

　　Modern flywheel energy storage technology is a comprehensive technology that integrates multiple disciplines. The main ways to increase energy density are:

　　The first is to improve the quality of the flywheel, the second is to increase the speed of the flywheel, and the third is to reduce its own losses.

　　Now flywheel energy storage technology is a comprehensive technology that integrates multiple disciplines: including flywheel material technology, bearing technology, motor technology, rotor dynamics, power electronics and other related technologies.

　　Flywheel bearing technology is a very core technology and has gone through several different stages of development: in the early days, it was purely mechanical bearings for support. The energy was proportional to the square of the rotational speed. The energy was increased by increasing the mass of the flywheel. Therefore, the corresponding flywheel has low energy density, low efficiency, and relatively short bearing life.

　　With the development of magnetic levitation technology, magnetic unloading mechanical bearings have been developed. During normal operation, the mechanical bearings run and unload part of the gravity through magnetic force, reducing the bearing capacity of the mechanical bearings, which can increase the speed of the flywheel and extend its life.

　　The latest technology now is completely magnetic suspension bearings. The flywheel is completely magnetically suspended when running, and there is no friction or contact with the bearings. Protected by spare mechanical bearings, this kind of flywheel has the characteristics of high speed, high energy density, high energy efficiency, and long bearing life. This is also the direction of the development of modern flywheel energy storage.

　　This is a flywheel energy storage rendering, which mainly includes the following core technologies:

　　First, five-axis active magnetic bearing and control technology. The upper and lower bearings enable the entire flywheel rotor system to operate stably. During operation, there is no contact between the flywheel rotor and the bearings, and the bearings are not worn.

　　Second, it runs at high speed, has a service life of more than 20 years, and a rotation speed of 37,000 rpm.

　　Third, alloy steel flywheel materials and process technology use aerospace-grade alloy steel flywheel materials, which have the advantages of high density, high strength, and strong anti-fatigue properties. They can simultaneously improve the quality and speed of the flywheel, and have good overall performance. Each flywheel All were treated non-destructively by ultrasound.

　　Fourth, brushless permanent magnet synchronous motor technology. It adopts brushless design and the rotor is made of rare earth Yongci material, which has high density and high efficiency.

　　Fifth, bidirectional power conversion and variable frequency drive technology uses IGBT for drive conversion, adaptively adjusts the frequency of AC power, and adopts variable frequency drive for AC motors.

　　Sixth, the vacuum chamber and heat dissipation technology are used to adopt a fully enclosed alloy shell, which plays the role of sealing, heat dissipation, battery evaluation and protection. It uses a vacuum pump to evacuate, detect and maintain the required vacuum degree in real time, and adopts a unique heat dissipation structure + Air-cooling heat dissipation technology maintains the thermal stability of the system.

　　Safety is the core part of energy storage technology, using multiple safety assurance technologies.

　　First, we use flywheel self-power supply technology, which is also our patented technology. During operation, the controller of the magnetic levitation bearing needs uninterrupted power supply. It adopts a two-way power supply design: one is an external auxiliary power supply, and the other is an internal automatic power supply. Power supply. The advantage is that the flywheel rotates at high speed, and the magnetic levitation controller is self-powered through the permanent magnet synchronous motor. Even in the event of external power outage, the power supply can be maintained uninterrupted.

　　Second, use backup mechanical bearing protection technology to achieve safe and smooth shutdown. Adopting a full range of status monitoring and protection technology, it can monitor electrical quantities, rotation speed, position, vacuum degree, temperature, and the operating status of each component in real time for real-time detection. The entire status is transparent and can automatically alarm if there are any abnormalities. downtime. Our products are very mature, with more than 1,700 devices in actual operation around the world, all operating safely and reliably.

　　Third, the magnetic levitation flywheel energy storage products and features adopt a standard cabinet design and include several parts, the first flywheel module part, the second graphical user interface, the third part flywheel control unit, and the fourth part magnetic levitation bearing control unit. Part 5 Bidirectional Converter.

　　There are now two series of products in mature mass production, one is called VDC series, the typical parameter rated power is 450KW, and the maximum available energy is 1.74KWh. There is also REGEN series, with a rated output power of 200KW, which can be used in 750V and 1500V. Through flywheel energy storage design, we can meet the needs of different application scenarios, ranging from several megawatts to tens of megawatts. DCS conversion is performed through PCS, and voltage is boosted through transformers, which can be controlled remotely or locally. Flywheel energy storage has great advantages over electrochemistry. The energy stored in flywheels strictly corresponds to the rotational speed. The corresponding energy at a certain rotational speed is certain. In this way, we can very accurately control the charging and discharging of each flywheel. , allowing everyone to fill or empty simultaneously.

　　Technical features of flywheel energy storage products:

　　1. High safety. The whole process is a physical energy storage process, without chemical reactions, all-round parameter monitoring, transparent status, safe and controllable;

　　2. Green and environmentally friendly, green and pollution-free throughout its life cycle. It is made of alloy steel and can be fully recycled after decommissioning, with low disposal costs;

　　3. Long life: Based on active magnetic suspension bearings, no mechanical friction, the core part can be used for up to 20 years;

　　4. High power;

　　5. Fast charging and discharging;

　　6. Wide temperature range;

　　7. Easy to deploy.

　　Fourth, the application scenarios of flywheel energy storage are particularly suitable for application scenarios that require high safety, high power, short time, and frequent charging and discharging. Focus on four types of application scenarios: urban rail transit regenerative braking energy recovery system, key power protection UPS, power frequency regulation, energy storage system for new energy regulation, and high-power energy storage power supply system to solve impact loads.

　　The flywheel energy storage type regenerative braking energy recovery system uses a variable frequency and variable voltage drive method in urban rail and subway transportation. When the subway is braking, electric braking is first performed to convert kinetic energy into electrical energy. Part of the energy is transferred to adjacent vehicles. outside of absorption. If the energy cannot be effectively absorbed, it will lead to an increase in the DC power of the traction network and affect the operation of the system. Therefore, the traditional solution is to use a braking resistor. This method wastes electric energy and is not energy-saving or environmentally friendly. If a flywheel energy storage device is used to recycle energy, the electrical energy that can be saved can account for about 15%-17% of the traction power.

　　The basic principle is introduced below: multiple flywheel energy storage devices are used to operate in parallel on the DC side, and a centralized control system is used to synchronously control the entire flywheel energy storage system to achieve synchronous charging and discharging, which is connected to the DC bus of the track traction network. , the system starts up and enters standby operation state. The electric energy is converted into kinetic energy and stored. When the train leaves the station, the flywheel stores energy and discharges, converting the kinetic energy into electric energy and releasing it. The main function is first to save energy. It can recycle the regenerative braking capacity and reduce operating costs. Second, it can perform bidirectional voltage stabilization. Third, you can cut the peak.

　　This system has a very mature application in the subway. This is our project in Los Angeles, USA. It was put into operation in 2014.

　　The following introduces the key power guarantee, flywheel energy storage UPS solution. UPS is a system used in many industrial fields. Nowadays, the commonly used UPS is bilateral conversion, which first undergoes rectification and then inversion. The energy storage supporting UPS traditionally uses lead-acid batteries, which have some problems, such as short life and high failure rate. According to statistics, more than 30% of the total failure rate of UPS is caused by battery failure. It occupies a large area, requires a separate room, and has relatively high temperature requirements. In addition, traction fluid is toxic and can cause pollution if used improperly.

　　Flywheel energy storage can replace lead-acid batteries and can be seamlessly exchanged with online UPS. Now we have a large number of applications with mainstream UPS brands. The main advantages of using UPS flywheel energy storage are long service life, 20-year use cycle, safety and reliability, low operation cost, small footprint, relatively wide requirements for ambient temperature, and full life cycle, green and pollution-free.

　　Working process: Normally, the flywheel is dived through rectification and inversion at the same time. When the power is cut off due to a fault, the flywheel energy storage is instantly discharged to ensure uninterrupted power supply to the load. This solution has many application cases, including data centers, telecommunications equipment rooms, semiconductor factories, etc.

　　Let’s introduce the hybrid energy storage solution of flywheel + battery. In the energy storage of the power system, there are different scale requirements for the charging and discharging time. For example, for new energy power generation, due to the randomness, volatility and intermittent nature of new energy power generation, the energy storage supporting new energy and microgrids has charging and discharging requirements of milliseconds and minutes, as well as minutes to hours. It is difficult to achieve perfection by relying on the current single energy storage method. Frequent short-term charging and discharging will quickly reduce the battery life. Therefore, we combine the functional battery energy storage method of flywheel and the energy-based method of battery to form a hybrid charging system, perform collaborative control, and achieve complementary advantages. This is a method of frequent charging and discharging in a short period of time.

　　For new energy station solutions, we can call the flywheel energy storage system or battery system as needed through the collaborative control system. For thermal power units + energy storage combined with AGC frequency regulation, the current typical preparation is based on the preparation of lithium-ion batteries and a typical design of 30 minutes. Experts from China Southern Power Grid also mentioned earlier that AGC frequency regulation power stations charge and discharge hundreds of times a day. For lithium-ion batteries, the life span is a ceiling, so we propose a hybrid system of flywheel + lithium battery, which is matched according to the proportion and controlled collaboratively.

　　When the AGC command has just been issued, the unit has not responded. At this time, the power is the highest. As the output of the unit gradually increases, the output of the energy storage part will decrease, forming a peak and a flat part. Therefore, the flywheel energy storage mainly bears the heavy load. Power, for short periods of time. Battery energy storage takes on the basic processing part, reduces charging and discharging frequency, and shortens lifespan.

　　This is a high-power flywheel energy storage power supply solution with impact resistance. This is characterized by the first sawtooth wave, where the power rises rapidly and then suddenly changes to form a cycle. The second is a square wave, and the third is a sudden increase or decrease in random power. It is characterized by large power fluctuations, rapid changes, short duration, frequent use, and impact loads that will have a greater impact on the diesel generator power supply system, microgrids, and large power grids, affecting the stability of the system and the life of the equipment. . Flywheel energy storage is very suitable for power sources with impact loads. We can reduce the configuration of generator unit capacity, extend the life of the unit, and improve the stability of the system. In addition, the high magnification characteristics are particularly suitable for high power input/output. Quick response, suitable for fast charging and discharging, and long life suitable for frequent charging and discharging.

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