With the rapid growth of the real estate industry, it has also driven the development of the elevator industry. Today, elevators have become a necessary configuration of high-rise buildings, in addition to the need for basic functions, people pursue more elevator safety and comfort, but few people care about the energy consumption of elevators, which makes elevators the second largest energy-consuming equipment in high-rise buildings after air conditioning.
Studying the history of the development of the elevator, we can find that the elevator control system from the original DC control to today's permanent magnet synchronous gearless control, each step of the development of elevator technology is accompanied by the reduction of elevator energy consumption, from this perspective, energy saving is the inevitable direction of the development of the elevator. However, the braking method used by the current elevator is still mostly for energy consumption braking, so that the renewable energy generated by the elevator is consumed by braking resistance heating, causing a lot of energy loss, increasing the temperature of the machine room, which not only leads to secondary waste of energy, but also affects the normal operation of the elevator.
Article 7 of the Special Equipment Safety Law of the People's Republic of China stipulates that special equipment production, operation and use units shall comply with this Law and other relevant laws and regulations, establish and improve special equipment safety and energy-saving liability system, strengthen special equipment safety and energy-saving management, ensure the production, operation and use of special equipment safety, and meet the energy-saving requirements.
Elevator mechanical energy-saving traction type elevator tractor, by pulling steel wire rope one end to connect the car, one end to connect the counterweight device, drive the car and counterweight up and down operation. Elevator tractor has a gear and no gear.
Elevator Energy Saving Technology
Geared tractors are usually driven by a gearbox to drive the traction wheel, and the gearbox is generally driven by a snail gear, with a reduction ratio of 35:2. There is no gearbox in the middle of a gearless tractor, powered by an AC permanent magnet synchronous motor, and the winding ratio is usually 2:1 or 1:1.
From the perspective of elevator energy-saving analysis, the gearless tractor is better than the geared tractor, but if you have to use the geared tractor as a power source, use a high-efficiency geared tractor. The geared tractor according to its main drive mechanism type is mainly divided into 3 types of snail, bevel gear and planetary gear, the transmission efficiency of the snail is very low, only about 70%; Planetary gear transmission and bevel gear transmission have a high transmission efficiency, can reach more than 90%, but because of its requirements for high gear machining accuracy and high cost, so its application is not wide.
In addition, the geared drive can use a permanent magnet synchronous motor, which is at least 10% more efficient than the AC asynchronous motor, which is an energy-saving modification for geared tractors.
Permanent magnet synchronous tractor has incomparable advantages compared to geared tractor. Permanent magnet synchronous tractor does not need to draw idle current from the grid, so its power factor is relatively high; Permanent magnet synchronous tractor does not need to induce magnetic winding, no induction loss, due to low surface heating, high efficiency, can be improved by 20% to 40%. Permanent magnet synchronous tractor adopts rotor magnetic field directional vector control, has the same excellent speed, torque control characteristics as DC motor, starting and braking current is significantly lower than induction motor, the required motor power and frequency converter capacity are reduced.
There are many ways to save energy in the elevator control system, one is to save energy with variable frequency regulation, and the other is to use feedback devices to save energy.
The frequency of the power grid used in China is 50HZ, the so-called variable frequency adjustment of energy saving, usually refers to the speed adjustment below 50HZ, that is, the frequency adjustment below the base frequency.
At the base frequency below the speed adjustment, that is, the speed adjustment under constant torque, according to the principle of the electric motor, can be known by T = 9.55P / n, when the torque T remains unchanged, the power P will change with the change in speed n, that is, when n increases, P will also increase, when n decreases, P will also decrease.
In the normal operation of the elevator, according to the number of passengers in the cabin, the corresponding function can be output by the frequency converter, that is, when the number of passengers is large, the frequency converter output is larger, and when the number of passengers is small, the frequency converter output is smaller, thus avoiding the phenomenon of small cars, thus achieving the purpose of energy saving of the elevator.
2. Using the energy saving of the feedback device, according to the principle of energy conservation, the elevator in the light load up, heavy load down and level downstairs, excess energy (including kinetic energy and potential energy) is converted into renewable electricity through the electric motor and frequency converter, and consumed by the heating resistance, frequent use will lead to an increase in the temperature in the machine room, need to be equipped with air conditioning for cooling. Otherwise, it will cause the elevator failure rate to rise.
The higher the operating floor, the more frequent the operating frequency, the greater the energy savings, greatly improving the efficient use of electricity. According to statistics, the energy consumed on the elevator brake resistor accounts for 25% ~ 35% of the total electricity consumption of the elevator, if this part of the energy can be recycled and reused, it can achieve the purpose of saving electricity.
Elevator Energy Saving Technology
The IPC-PFE series of elevator energy-saving devices produced by Shenzhen Hexing Ga Energy Technology Co., Ltd. can not only reduce the machine room temperature, but also effectively recover renewable energy, or feed back to the grid, or supply other electrical equipment (air conditioning, computers, electric lights, etc.) to save the energy of the grid.
Elevator energy saving and reduction technology will certainly become an important direction for the future research and development of elevators, and will also become one of the frontrunners of the national "energy saving and emission reduction" policy.