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Application of Haipumont HD5E escalator special drive controller on escalator
With economic development and technological progress, there are more and more applications of escalators. At present, the number of escalators in China has exceeded 1 million.
Escalator system not only brings convenience and quick keys to people, but also consumes a lot of electricity. With the advancement of energy conservation and emission reduction, escalator energy conservation is imperative.
The "Regulations on Energy Conservation in Public Institutions" promulgated by the State Council on October 1, 2008 were formally implemented, and it has guided the development trend of escalator energy conservation in the form of laws.
Escalators are widely used in shopping malls, airports, subways and other public places. They run at the rated speed after being opened. When no one is on the elevator, the escalator still runs at high speed, which consumes a lot of electrical energy and wears down the mechanical parts of the elevator. If the running speed of the escalator can be reduced when no one is on the escalator, or even stop the escalator running, it can save electric energy, reduce the abrasion of the elevator mechanical parts, and increase the service life of the elevator.
2 Analysis of the existing escalator system
2.1 Non-energy-saving escalator system
Most of the current escalator applications are non-energy-saving escalator control systems. Use PLC or special control board as the core of the escalator control system. After the control system receives the start signal, it controls the action of the corresponding contactor, and the power grid drives the escalator up or down. These systems all have functions such as escalator protection logic, refueling and buzzer. Non-energy-saving escalators can only control the escalator to run at the rated speed or stop the escalator.
2.2 Y-△ step-down start energy-saving escalator system
In this scheme, when no one is on the elevator, the contactor is disconnected, the motor is de-energized, and the escalator stops; when someone is on the elevator, the escalator Y-△ depressurization starts and runs quickly. This kind of system can achieve the purpose of saving energy, but it is frequently started and stopped. Although it is started with Y-△ step-down voltage, it still has a big impact on the escalator power grid when it starts. Therefore, this scheme is rarely used.
2.3 Energy-saving escalator system with general frequency converter The frequency converter has the function of speed regulation, which can realize the soft start of the motor, and can make the escalator run at different speeds according to the demand. However, the general-purpose inverter itself does not have the relevant logic of escalator control, and needs to be used with other controllers. The other controllers complete the escalator control logic.
Receive up and down photoelectric signals, output fast or slow running commands to the inverter, and the inverter drives the escalator to run fast or slow. Since it is always frequency conversion operation, the elevator will generate power when it is going down. At this time, the inverter needs to be equipped with a braking resistor. Although this type of system can achieve soft start and low-speed energy saving, the system structure is complicated and the cost is relatively high.
3 HD5E technical features
HD5E special drive controller for escalators uses advanced customized design concepts, focuses on the needs of the escalator industry, and perfectly combines advanced motor control technology with escalator control logic. The product has a variety of escalator operation modes, excellent bypass frequency conversion technology, perfect escalator control logic and escalator failure protection, which can meet all kinds of escalator transformation and new elevator applications.
3.1 Multiple escalator operation modes
(1) Bypass variable frequency operation mode
When someone takes the elevator, the drive controller controls the escalator to accelerate to the power frequency, and the escalator is switched from the variable frequency drive to the power frequency drive; when no one is on the elevator, the escalator is driven by the variable frequency and runs at low speed.
(2) Full frequency conversion operation mode
Whether there are people on the elevator, the escalator is always in variable frequency drive operation, running at high speed when there are people on the elevator, and running at low speed and energy saving when no one is on the elevator.
(3) Power frequency Y-△ operation mode
The escalator adopts Y-△ step-down start to reduce the impact on the escalator and the power grid. After the start, the escalator is driven by the power frequency. When the variable frequency output is abnormal, the escalator system can run in the power frequency Y-△ operating mode, and a system provides 2 options.
(4) Maintenance operation
The overhaul operation is divided into frequency conversion overhaul and industrial frequency Y-△ overhaul. The input, output signals and operating status of the escalator system are checked in the frequency conversion state and the industrial frequency state respectively.
3.2 Excellent bypass frequency conversion technology
When the escalator is switched from frequency conversion to industrial frequency, the excellent phase locking technology makes the impact current when switching is small, and the escalator has no jitter.
When the escalator switches from industrial frequency to variable frequency, the ultra-smooth speed tracking technology realizes shock-free starting.
3.3 Three energy-saving operation modes
HD5E provides three different energy-saving operation modes: unmanned elevator running at low speed, unmanned elevator first running at low speed and then stopped, and unmanned elevator stopping running. It also provides forward express time, slow operation time, and express operation frequency. Function parameters such as slow car running frequency and so on can be set by users themselves, which can flexibly meet the energy-saving needs of different applications.
3.4 Perfect escalator failure protection
In addition to the various protection functions of the inverter, HD5E also provides safety circuit disconnection protection, anti-reversal protection, drive chain broken protection, motor speed measurement protection, handrail speed measurement protection, upper and lower step loss protection, and contact adhesion for the escalator system. Complete escalator failure protection logic such as protection, contactor contact feedback disconnection protection, fire alarm protection, etc., fully meet industry standards and relevant national technical requirements to ensure safe and reliable operation of escalators.
4 HD5E application case
4.1 HD5E energy-saving retrofit application case
In the transformation and application, the composition of the original system needs to be carefully analyzed. At present, the escalator control system with PLC as the core or the escalator system with the special control board as the core are generally used in the market. When retrofitting, users generally require that the original system cannot be changed significantly. The energy-saving retrofit of the escalator with minimal changes is a requirement for many retrofit occasions.
In this kind of transformation occasion, we choose the transformation plan of full frequency conversion operation mode.
The system structure diagram is as follows:
In the above scheme, only three signals of up command, down command and stop command are required from the original system. The protection logic of the escalator is still completed by the original system, but the main power of the original system is not output to the motor, and the motor is driven by HD5E variable frequency. The increased upper photoelectric and lower photoelectric signals are respectively installed at the upper and lower entrances of the escalator to detect whether someone is taking the elevator. When someone takes the elevator, HD5E drives the escalator to run at high speed;
When no one is on the elevator, HD5E drives the escalator to run at low speed and energy saving or stop running.
This kind of scheme can simply realize the energy-saving transformation of the escalator. Due to the full frequency conversion operation, when the escalator is carrying people down, the energy is fed back to the HD5E, and it is generally necessary to configure a braking resistor to discharge the feedback energy to prevent the HD5E from over-voltage faults. In addition, it should be noted that the original system is generally equipped with speed measurement protection, and the benchmark of the original system speed measurement protection is the rated elevator speed. When the escalator runs at low speed, the original system will report the speed measurement protection failure. At this time, the original system speed measurement protection needs to be shielded. Then the speed measurement signal is input into HD5E, and HD5E realizes speed measurement protection. HD5E provides a complete variety of speed measurement protection, which can completely protect the speed abnormality that may occur on the escalator.
4.2 HD5E New Ladder Application Case
In new elevator applications, it can give full play to HD5E's advanced motor control performance and perfect escalator control logic. HD5E can not only complete the escalator control logic but also complete the frequency conversion speed regulation of the motor. The escalator control system composed of HD5E no longer needs other control devices, and the high degree of integration improves the reliability and maintainability of the system.
In the new elevator application, the bypass frequency conversion operation mode is adopted, and Y contactor and delta contactor are equipped as backup. When the frequency conversion output is abnormal, it can be switched to the power frequency Y-delta operation mode to improve the reliability of the escalator system operation.
Among them: KM1 is the variable frequency output contactor; KM2a is the grid up contactor; KM2b is the grid down contactor; KM3a is the Y contactor; KM3b is the delta contactor.
The escalator control system composed of HD5E escalator special drive controller has the following advantages
(1) Realize the frequency conversion speed regulation of the motor, save energy, reduce the impact and wear of the escalator, and increase the service life of the escalator.
(2) The use of bypass frequency conversion technology reduces the working time of HD5E frequency conversion output and increases the service life of HD5E; since HD5E only frequency conversion output during startup and low speed, it can be used in downshifts, saving system costs; switching at high speed To power frequency operation, there is no need to configure a braking resistor, which saves space in the control cabinet and reduces heat generation.
(3) Integrating advanced motor control technology and perfect escalator control logic, simplifying the composition of the system and improving the reliability and maintainability of the system.
(4) The power frequency Y-△ operation mode is provided as the backup of the system. When the frequency conversion output is abnormal, the escalator can be driven by the power frequency, which further improves the reliability of the escalator system.
(5) A variety of energy-saving modes and flexible function parameter settings can meet the needs of different applications.
4.3 HD5E energy saving analysis
The calculation formula of power P is as follows:
Among them, U is the line voltage, I is the phase current, and Cosj is the power factor. Take an escalator driven by a 7.5Kw motor as an example. When the escalator runs at a high speed of 50Hz with no load, the output line voltage is 380V, the output phase current is 8A, and the power factor is low when the motor is lightly loaded. Assuming it is 0.5, the power P is calculated as follows.
When the escalator runs at a low speed of 10Hz with no load, the output line voltage is about 80V, and the output phase current is 8A. The power factor of the motor rises slightly at low speed. Assuming it is 0.7, the power P is calculated as follows.
Compared with 50Hz operation, when running at a low speed of 10Hz, it can save nearly 2Kwh of electric energy per hour. If it runs at low speed for 5 hours a day, it can save 10Kwh of electric energy a day. The escalator can also run at low speed and then stop running mode when unmanned, which can save more electric energy when it stops running. The above calculations illustrate the huge advantages of HD5E in terms of energy saving. Of course, different applications have different energy-saving effects, which are mainly related to the motor current and motor power factor when the escalator is unloaded.
Practice has proved that HD5E escalator special drive controller has won the recognition of customers for its excellent performance, rich and flexible functions, and reliable and stable performance, whether it is in the old elevator renovation or the new elevator application. HD5E will definitely make due contributions to the upgrade of the escalator system and the promotion of energy saving and emission reduction.