How can supercapacitor module achieve high efficiency and energy saving in the braking energy recovery of urban rail transit?
Publish Time: 2024-12-05
With the expansion of urban population, urban rail transit is becoming more and more important. However, as a large-volume and high-density means of transportation, rail transit consumes huge amounts of energy. According to statistics, trains can feed back a large amount of electrical energy during braking. If this part of energy is recycled and reused, it can not only reduce a large amount of energy consumption, but also reduce the burden on the power grid. As a high-efficiency energy storage device, supercapacitor module plays an important role in the braking energy recovery of urban rail transit.
The main braking methods of urban rail transit are electric braking (including regenerative braking and resistor braking) and air braking. When the vehicle is running at high speed, regenerative braking and resistor braking are mainly used. When the vehicle is decelerated to the point where electric braking does not work, air braking is used. During the operation of the train, due to the short station spacing and frequent train starts and brakes, the braking energy is considerable, which can reach 40% to 50% of the traction energy. However, the traditional braking energy processing method often consumes the braking energy in the form of heat energy through resistors, which not only causes energy waste, but also increases the burden on the environmental control device in the station, and brings about temperature rise problems in tunnels and platforms.
In the braking energy recovery of urban rail transit, the supercapacitor module is connected in parallel with the DC power supply bus of the subway train through a bidirectional DC converter. When the subway train brakes, the DC bus voltage rises, and the bidirectional DC converter charges the supercapacitor array to absorb the braking energy; when the subway train starts, the DC bus voltage drops, and the energy stored in the supercapacitor array is released through the bidirectional DC converter to provide partial power support for the train. This method achieves the functions of "peak shaving and valley filling", balancing the DC side voltage and energy recovery and reuse.
The advantages of the supercapacitor module in braking energy recovery are mainly reflected in the following aspects:
Efficient energy storage: Supercapacitors have the ability to charge and discharge quickly, and the charging and discharging efficiency can reach about 99%, which can efficiently store and release braking energy.
Long life: Supercapacitors can be repeatedly cycled hundreds of thousands of times, far exceeding the life of rechargeable batteries, reducing replacement and maintenance costs.
Environmental protection: Supercapacitors are a green energy source that does not generate pollution during the charging and discharging process, which is in line with the country's energy conservation, emission reduction, and low-carbon environmental protection policies.
Stabilize grid voltage: Through the energy storage and release of supercapacitor modules, the voltage of the traction grid can be stabilized, reducing the impact of voltage fluctuations on the grid and equipment.
Supercapacitor modules can achieve high efficiency and energy saving in the braking energy recovery of urban rail transit, which not only reduces energy waste, but also reduces operating costs, and improves the environmental protection performance and economic benefits of urban rail transit.
