Energy-saving device and method capable of feeding back electric energy to power grid from parallel connection

Abstract

The invention provides an energy-saving device capable of feeding back electric energy to a power grid from parallel connection. The device adopts double closed-loop control of a direct current bus voltage control loop and a feedback current control loop, and adjusts the size of feedback current according to output of the direct current bus voltage control loop. The invention also provides an energy-saving method capable of feeding back electric energy to the power grid from parallel connection. By implementation of the energy-saving device and the method disclosed by the invention, the beneficial effects are that: firstly, double closed-loop control of the direct current bus voltage control loop and the feedback current control loop are adopted, and the size of the feedback current is adjusted according to the output of the direct current bus voltage control loop so as to ensure that no effect on the power grid is generated while feeding back electric energy to the power grid, and secondly, field application and field combination are flexible, one energy-saving device is connected between the power grid and one or more transducers to achieve electric energy feedback on the occasion of low power, and a plurality of energy-saving devices are connected between the power grid and one or more transducers to achieve electric energy feedback.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more specifically relates to an energy-saving device and method capable of self-parallel feeding back electric energy to a power grid. Background technique [0002] A crane is an electromechanical device that places heavy objects by vertical lifting or vertical lifting and horizontal movement. With the continuous development of technology, in order to ensure the safe and stable operation of cranes, the demand for speed control accuracy is increasing. At present, more and more on-site control uses frequency converters to control motor operation. However, there will be a problem when using frequency converter control. When the heavy load is lowered, its load position can be converted into electrical energy through the motor and stored in the DC capacitor, and the converted electrical energy will be stored in the DC capacitor when the crane brakes. It will cause the voltage of...

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide an energy-saving device capable of self-parallel feeding back electric energy to the power grid in view of the defect in the prior art that the electric energy generated during the operation of the crane cannot be well fed back to the power grid

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