The supplier of the elevator energy feedback device reminds you that the operation of the elevator is a reverse movement of the car and the counterweight device, and the counterweight is generally heavier than the car. The elevator is driven up and down by a traction machine, and the load driven by the traction machine is composed of a passenger car and a counterweight balance block. Only when the load capacity of the car is about 50% (such as a 1-ton passenger elevator with about 7 passengers), the car and the counterweight balance block will balance each other. Otherwise, there will be a quality difference between the car and the counterweight.
The operation process of an elevator is the process of converting electrical energy into mechanical energy. When the elevator is overloaded and moving up or lightly loaded and moving down, energy needs to be provided to the elevator to increase the mechanical potential energy. The elevator converts electrical energy into mechanical potential energy through a traction machine, which is in a power consuming state; When the elevator is lightly loaded up or heavily loaded down, the operation process needs to reduce the mechanical potential energy. The mechanical potential energy of the elevator is converted into electrical energy by the traction machine, which is in a generating state.
In addition, the process of elevators from high-speed operation to braking stop is a process of mechanical kinetic energy consumption, and a part of the kinetic energy is converted into electrical energy by the traction machine, which is in the process of generating electricity. The electrical energy generated during the power generation process of the traction machine needs to be dealt with in a timely manner, otherwise it will pose serious harm to the traction machine. For variable frequency elevators, the electrical energy generated by the traction machine during the power generation process is reversed back to the DC end of the frequency converter through the three-phase inverter bridge of the frequency converter and stored in the DC capacitor. However, the capacity of the DC capacitor is limited. When the electrical energy generated by the traction machine exceeds the capacity of the DC capacitor, it will cause damage to the DC capacitor, so the excess electrical energy must be consumed.
The conventional method for handling this part of electrical energy in a variable frequency elevator is to install a braking unit and a braking resistor at the DC capacitor end. When the voltage across the capacitor reaches a certain value, the braking unit will activate, and the excess electrical energy will be converted into thermal energy through the braking resistor and dissipated into the air. The electric energy feedback device replaces the braking unit and braking resistor. By automatically detecting the DC bus voltage of the frequency converter, the DC voltage of the DC link of the frequency converter is reversed into an AC voltage with the same frequency and phase as the grid voltage. After multiple noise filtering links, it is connected to the AC power grid to achieve green, environmentally friendly, and energy-saving goals.
The elevator energy feedback device is a device that converts the electrical energy generated by the traction machine of the elevator under unbalanced load into high-quality AC power of the same frequency and phase as the power grid, and returns it to the local power grid through inversion. For use in elevator motherboards, elevator shaft lighting, car lighting, car fans, and nearby areas with loads (or other parallel elevators and ancillary equipment).