A DC power supply system for drilling rig and its control method

Abstract

A direct current supply system for a drilling machine comprises a direct current supply bus (30), a first electric generator (11), a first rectifier (21), a second electric generator (12), a second rectifier (22), a first inverter (51), a top drive motor (71), a second inverter (52), a slush pump motor (72), a third inverter (53), a winch motor (73), a fourth inverter (54), other motors (74), a fifth inverter (55), other loads (75) for household consumption, an energy storage unit (80), a resistance braking unit (90) and a controller (100) coupled with the electric generators, the rectifiers, the inverters, the energy storage unit and the resistance braking unit. According to the direct current supply system for the drilling machine, the working efficiency and reliability can be improved, the energy storage capacity needing to be configured can be reduced, and the cost performance is improved.

Description

technical field [0001] The invention relates to a direct current power supply system for a drilling rig and a control method thereof. Background technique [0002] At present, the oil drilling rig system is generally composed of generators, AC busbars, and motor systems. One of its outstanding features is that it has an AC bus with relatively fixed frequency and voltage amplitude. The AC bus is generally 690V, 50Hz or 60Hz. The generators are all connected to this AC bus, which will greatly limit the degree of freedom of regulation of the generator control system, because its output frequency and voltage amplitude are strictly limited. Other loads such as domestic electricity are generally powered by 380V, which is usually obtained by converting 690V power through a transformer. Drilling rigs generally include a variety of variable frequency motor drive systems such as winches, mud pumps, and top drives, all of which are connected to the AC bus. [0003] The drive system...

AI Technical Summary

Problems solved by technology

Chinese patent ZL200820221729.1 proposes a method of using a DC energy storage device to absorb braking energy, but since the consumed energy is far less than the regenerative braking energy in a long period of time, the required DC energy storage device has a large storage energy , the economy is low, and there may even be a problem that the energy storage is full and cannot provide braking energy to solve the problem

However, in this scheme, the energy storage device is connected to the 50Hz AC bus, and the sudden change of the generator load is detected by detecting the deviation of the frequency of the AC bus. The detection algorithm is complicated and the detection speed is slow, which will lead to the compensation speed and Accuracy suffers

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