DC system for container piling site tyre hoister

Abstract

The invention discloses a DC supplying system of container yard tyre suspension, which consists of power supplying device of tyre suspension and power receiving device, wherein the power supplying deice of tyre suspension contains at least one AC-to-DC conversion device and electrical net of public DC bus in the whole container yard; the electrical net of public DC bus connects a high-voltage AC power through AC-to-DC conversion device; the power receiving device connects the electrical net of public DC bus; the tyre suspension has power supplying system with complete maneuverability to share and allocate energy on the electric net of public DC bus among tyre suspensions, which reduces the loss to realize multiple-point power supplying pattern. The invention possesses simple structure and low cost, which reduces pollution to provide convenience for working.

Description

technical field [0001] The invention relates to the technical field of container loading and unloading, in particular to the field of power supply systems for tire cranes in container yards, and in particular to a DC power supply system for tire cranes in container yards. Background technique [0002] In modern society, there are more and more various container terminals, and the container terminal yard loading and unloading equipment mainly adopts tire cranes. Most of the tire cranes in the prior art are powered by diesel engines, which are flexible in transition, but the efficiency of the huge diesel generator set is very low, the reactive power consumption is large, the noise is large, and the environment is also polluted by smoke and dust. [0003] At the same time, a system that can directly supply power from the AC power grid has appeared in the prior art, thus changing the tire crane from using diesel to directly using electric energy (referred to as "oil to electrici...

AI Technical Summary

Problems solved by technology

Most of the tire cranes in the prior art are powered by diesel engines with flexible transitions, but the efficiency of the huge diesel generator set is very low, the reactive power consumption is large, the noise is large, and the environment is also polluted by smoke and dust.

[0003] At the same time, a system that can directly supply power from the AC power grid has appeared in the prior art, thus changing the tire crane from using diesel to directly using electric energy (referred to as "oil to electricity"), which can reduce to a large extent Energy consumption costs, but often bring new problems to the "flexible transition" of the tire crane

Since the power supply provided by the diesel engine is three-phase low-voltage alternating current, the simplest and direct method of "replacing oil with electricity" is to provide a suitable AC grid for power supply to the tire crane. There are many feasibility and operability issues:

[0004] First of all, a lot of energy will be released when the crane brakes and lowers the weight, and it will directly appear as a DC state. This is because the current inverters all adopt the "AC-DC-AC" structure, and the inverters use AC If the side is connected, the AC power supply is used. Between the tire cranes, the various frequency conversion speed control devices of the tire cranes and other electrical equipment cannot directly automatically distribute the DC power supply energy to each other. In this way, the process of placing heavy objects under the tire crane The energy generated in the inverter has to be wasted; there are also inverter modules from DC to AC power in the above-mentioned frequency conversion speed control devices to use the energy of regenerative power, that is, to invert the regenerated DC power into AC on the grid. AC, and then rectified by another inverter that is consuming power to DC for its motor, which is equivalent to allowing the electric energy to go through an additional transformation such as "DC-AC-DC", because the above method requires an additional inverter module (or purchase a frequency conversion speed control device that can be fed back to the grid), the cost is often very high, and the inverter module will cause the loss of AC grid harmonics and energy regeneration inverter

[0005] Secondly, in order to reduce the big problems caused by the "oil-to-electricity" change to the "flexible transition" of the tire crane, it is necessary to form a power supply grid as large as possible in the container yard, so that the tire crane can use the slide wire conductor to supply power along the The power grid moves, and there are many troubles in using the AC grid to form a large-area, long-distance, low-voltage public grid. Due to the low voltage, the current required for the same output power is relatively large. In order to ensure that the current is transmitted on the wire to maintain low energy and Voltage loss, the wire must be very thick, thus increasing the cost and difficulty of construction; the use of multi-point power supply can help solve the above-mentioned long-distance transmission problem of electric energy, but the AC power must be connected to the grid in the same phase, so that the transformer of the grid and the AC power supply connected to the grid Phase measurement and control put forward high requirements, also resulting in increased cost and reduced reliability of this method

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