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EM12 series frequency inverter used for elevator application
Publish:China EM Technology Limited  Time:2018-03-20
EM12 series frequency inverter used for elevator application

    The fully automatic torque boosting function of the EM12 inverter achieves good comfort and stability in elevators applications. It can accept multi-speed frequency command or analog voltage and current command of controller such as PLC; It can adapt to various motors through auto-tuning, and obtain good vector control characteristics. Its stable startability at low speed is excellent. Hardware reliability and cost performance are extremely high also .
     In this application,Model selection and others accessories selection as below:
Braking unit and braking resistor should be installed with VFD together in elevator application, It obtains sufficient braking torque in the regenerative state;
AC reactor is also needed in long-term generator operation and other special places.
Inverter should be increased one rate according to the power of the motor. In order to obtain the ideal control performance of the inverter, the general inverter power should meet the following formula:
power of VFDK×1.732×Vm×Im
(K is the current waveform correction factor, Vm is the motor rated voltage, and Im is the motor rated current)
    when the elevator no-load up or down with heavy load, motor will be in the regenerative power generation braking operation state, so the energy fed back by the motor flows to the DC part to charge the filter capacitor through the parallel diode of the inverting process. When the feedback energy is large, it will cause the DC voltage to rise and the fault will occur, and the rapid deceleration of the motor will also cause the above phenomenon. The solution is to connect the brake unit and the braking resistor to VFD. The brake unit is an optional component of VFD. It is equipped with a detection and control circuit. It works online to detect the DC link voltage of the inverter. When the voltage exceeds the set response value, the trigger brake transistor is turned on, and the DC bus voltage of the inverter is maintained in the normal working range through the resistance release energy, and a braking unit can be connected in parallel with several resistors,details depends on the working.
     Project details for reference as below:
     Take one project used for middle speed elevator for example,tractor motor is 11KW asynchronous motor,VFD is EM12-G3-015/P3-018,construction as below:

VFD parameters setting
    1. In order to meet the requirements of operating efficiency, comfort, leveling accuracy and safety in elevator control,several main parameters will be introduced as below: in order to reduce the starting impact and increase the passenger‘s comfort, the speed loop of the speed control system The proportionality factor should be smaller, and the integral time constant should be larger. In order to improve the operating efficiency, the speed of the express train should be chosen to be 50HZ, and the creeping frequency should be as low as possible to reduce the parking shock, so choose 6HZ. The speed of overhauling the slow train can be 12hz. The “s” curve feature prevents vibrations during start-up, speed change or stop, which is most suitable for use in elevators, which greatly improves ride comfort. In addition, the fault diagnosis, detection, memory and other functions of the inverter are also very convenient and practical for system maintenance.  Other common parameters of the inverter can be directly input according to the grid voltage and the motor nameplate parameters. The elevator runs the ideal curve as shown

2. After completing the parameter setting, the inverter needs to auto-tuning the motor. The method is: detach the traction machine brake wheel from the motor shaft, make the motor in no-load state, and then start the motor, the inverter can automatically identify and store parameters of the motor.
The specific parameters are set as follows:

Application photo for reference:

Feedback from customer:
    After EMHEATER inverter used for this application,the elevator is stable and comfort with high safety,the maintenance cost is greatly reduced,customer said EMHEATER inverter is the best high performance inverter.