Device and system for storing mixed energy of lifting system, and control method

Abstract

The invention discloses a device and a system for storing mixed energy of a lifting system, and a control method. The device comprises a DC protection current breaking unit, a mixed energy storing unit, and a BMS system control unit. The mixed energy storing unit is electrically connected with the DC protection current breaking unit and the BMS system control unit. The BMS system control unit controls the mixed energy storing unit to charge / discharge according to acquired voltage of the mixed energy storing unit, a DC bus, and a power grid. The mixed energy storing unit absorbs feedback energythrough the DC protection current breaking unit to realize charging, the feedback energy being generated by a power system which is electrically connected with the DC bus, or supplies power for the power system connected with the DC bus through the DC protection current breaking unit to realize discharge. The device and the system can realize double power mixed power supply, and make the power system work stably. The device and the system recycle the feedback energy fed back by the power system, and the feedback energy is recycled and used, capacity of a transformer is reduced, to achieve energy-saving effect.

Description

technical field [0001] The present invention relates to the technical field of new energy applications, in particular to a lifting system hybrid energy storage device, system and control method, which are applied to the power system of container terminal port machinery equipment, specifically rail-type shore bridge cranes, rubber tire doors Cranes and gantry cranes. Background technique [0002] At present, the power system of traditional quay cranes uses a single mains power grid as power, and consists of two large-capacity transformers to supply power to the power system and auxiliary systems. Usually, the capacity of the main transformer is ≥2500KVA, and the capacity of the auxiliary transformer is ≥250KVA. The overall power system efficiency is less than 40 %. The main reasons are as follows: [0003] a) Large installed capacity: Considering that the short-term maximum load demand of the quay crane power system must be met, the capacity and power of the transformer mus...

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Problems solved by technology

[0002] At present, the power system of traditional quay cranes uses a single mains power grid as power, and is composed of two large-capacity transformers to supply power to the power system and auxiliary systems. Usually, the capacity of the main transformer is ≥2500KVA, and the capacity of the auxiliary transformer is ≥250KVA. The overall power system efficiency is less than 40 %

[0003] a) Large installed capacity: Considering that the short-term peak load demand of the quay crane power system must be met, the capacity and power of the transformer must be matched according to the peak demand of the quay crane power system, which is more than twice the average power of the quay crane, resulting in the power supply system of the quay crane Large investment and high operating costs;

[0004] b) Low power efficiency: Affected by the difference in peak and valley fluctuations in energy demand during quay crane operations, the power factor of the quay crane transformer is low, resulting in low overall power efficiency of the quay crane;

[0005] c) Braking energy recovery function: the energy feedback system adopted by the quay bridge is to feed back the energy directly from the main circuit through the transformer of the quay bridge to the market when the hoisting mechanism of the quay bridge is lowered, the trolley is running, and the traveling mechanism of the cart is decelerating and braking. In the power grid, due to the existence of harmonics and unstable power quality in the feedback power, and the long part of the transmission line is converted into heat energy loss, the feedback energy cannot be stored and better recycled;

[0006] d) The quay crane usually adopts a single power supply mode. When the port substation suddenly loses power or the voltage fluctuates greatly, so that the mains power supply cannot provide power for the quay crane operation, the quay crane itself does not have an emergency power supply device, resulting in the quay crane in the port. There are safety hazards in the operation

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