1. Overview
The driving objects of the frequency converter of the drilling platform are mainly winches, turntables and mud pumps.
The frequency conversion transmission equipment generally adopts the common DC bus scheme. For the system connected to the power grid, the rectifier unit can be configured with feedback, and the centralized brake unit must be configured on the DC bus if it cannot be feedback.
The winch of the drilling platform has load characteristics similar to that of the lifting application, which requires the inverter to have open/closed loop vector control, large starting torque, zero speed hover function, and for the deep well platform, it may involve one master and multiple slave synchronous control.
The rig's turntable requires torque limiting to prevent torque or parts from breaking.
2.frequency conversion drive scheme
Oil drilling system adopts HD2000 series water-cooled frequency converter, system composition includes: Power supply system, two 2.3MW rectifier units, three 1.7MW mud pump units, two 1.2MW winch units, one 1MW turntable unit, three 1.2MW centralized brake units, water cooling system, corresponding motors for each inverter unit, and external brake resistors. The power units of the winch unit and the turntable unit are designed with a rated power of 1.4MW.
Among them:
1. The whole system can be powered by power grid or diesel generator on site;
2. Two rectifier units and all inverter units, brake units common bus;
3. Three brake units in a unit cabinet;
4. Three mud pumps can be towed two, that is, the output with two 600kW coaxial motors running in parallel;
5. Winch A and winch B operate in master-slave mode;
6. The winch and turntable are equipped with a code tray module;
7. The water cooling system adopts a double pump system, and the circulating pump can be selected arbitrarily during operation.
The system topology is as follows:
The water-cooled multi-transmission frequency converter of oil drilling uses 8 HCU20 controllers to independently control the rectifier and inverter units, ensure the reliability of the system operation, and realize the communication and status signal transmission with the main control PLC, water cooler, brake and code disc.
Among them:
1. The communication between the main control PLC and each HCU20 can choose Profinet bus or Profibus bus;
2. The master-slave control mode is realized between winch A and winch B;
3. The water-cooled cabinet can be controlled locally, or can be controlled remotely by the controller of rectifier 1.
4. The brake unit establishes communication with the rectifier 2 controller, and the status information of the brake unit can be transferred to the rectifier 2 controller, or the fault reset of the brake unit can be realized through the rectifier 2 controller;
5. Mud pump is VF mode operation, winch and turntable are CLVC (with code plate vector control) operation;
6. Each HCU20 controller is equipped with sufficient AI, AO, DI, and DO signal interfaces for backup.
The control system topology is as follows:
