A pure electric rotary drilling rig power system and its control method

Abstract

The present invention relates to a power system of a pure electric rotary drilling rig and a control method thereof. The power system comprises: a power battery, a battery management system and a DC bus. The DC bus is connected to a working motor through a motor controller. The working motor includes a main hoist motor, a power head motor and a main pump motor. The DC bus is connected to an inverter, and the inverter is used to connect to a distribution box through an external cable, and the distribution box is used to connect to the power grid. Among them, the main hoist motor is used to drive the main hoist; the power head motor is used to drive the drill bit; the main pump motor is used to drive a pump set, and the pump set is connected to each hydraulic working component. The present invention improves the working condition adaptability of the electric rotary drilling rig, reduces the operation power consumption, and improves the safety and reliability of the system.

Description

Technical Field

[0001] The present invention relates to the field of rotary drilling rigs, and in particular to a fully electric rotary drilling rig power system and its control method. Background Art

[0002] Currently, the basic structure of a fully electric rotary drilling rig is that a driving motor directly drives a hydraulic pump to provide power. The driving motor is powered by an external power grid. The motor drives the hydraulic pump to output hydraulic oil to a hydraulic control valve, and the hydraulic control valve inputs hydraulic oil with direction, pressure, and flow to a motor or a cylinder, and the motor or the cylinder drives an actuator to complete various actions. In this solution, the motor directly drives a pump group (main pump, auxiliary pump, gear pump, pilot pump, etc.), and the motor continues to work in the standby state to maintain the hydraulic pressure of the pipelines of each operation path.

[0003] Currently, this type of fully electric rotary drilling rig has the following disadvantages:

[0004] ① It is necessary to configure a high-power motor to meet the requirements of different operation load changes. During the operation process, the working point is continuously adjusted with the change of the load, and the motor efficiency is poor; ② Each operation component is driven by a hydraulic system. The hydraulic system has a long transmission path and many pipeline losses, and the overall transmission efficiency is low, resulting in high energy consumption losses; ③ It is powered by an external cable. Limited by the power of the distribution cabinets at different construction sites, the cable power supply capacity is greatly affected by the construction site scenario factors, and the adaptability of the drilling operation effect of the whole machine is poor; ④ Energy recovery cannot be achieved. Summary of the Invention

[0005] The purpose of the present application is to provide a fully electric rotary drilling rig power system to solve the problem of low motor efficiency in the prior art. At the same time, the present invention also provides a control method for the fully electric rotary drilling rig power system.

[0006] To achieve the above purpose, the present invention proposes a fully electric rotary drilling rig power system, including:

[0007] A DC bus, the DC bus is connected to a working motor through a motor controller. The working motor includes a main hoist motor, a power head motor, and a main pump motor; the DC bus is connected in parallel with two power supplies. One path includes a connected converter, and the converter is used to connect to a distribution box through an external cable, and the distribution box is used to connect to the power grid; the other path is a power battery, and the power battery is connected to the DC bus;

[0008] Among them, the main hoist motor is used to drive the main hoist; the power head motor is used to drive the drill bit; the main pump motor is used to drive a pump group, and the pump group is connected to each hydraulic operation component.

[0009] Further, the converter is a vehicle-mounted rectifier cabinet, which is used to convert the alternating current of the external power grid into direct current.

[0010] Further, the motor controller is an all-in-one controller or several independent motor controllers, and each motor controller is respectively connected to a working motor.

[0011] Further, the working motors further include a slewing motor and a traveling motor.

[0012] Further, each type of working motor includes more than one motor.

[0013] Further, the main hoist system includes a main hoist motor, a main hoist, and a brake. The main hoist motor drives the main hoist, and the brake is arranged between the main hoist motor and the main hoist.

[0014] The present invention also provides a control method, and the steps include:

[0015] When the whole machine is powered on normally and receives a working speed command, the main hoist motor performs torque control and reads the memory torque at the last shutdown as the target torque;

[0016] The main hoist motor increases the torque. When the torque reaches the target torque, it requests the brake to open; if the torque of the main hoist motor cannot be increased to the target torque and exceeds the set torque response period, the motor shuts down;

[0017] After the brake is opened, the main hoist motor works normally;

[0018] During the working process, when a shutdown command is received, or an abnormal fault alarm of the main hoist occurs, or an emergency brake is triggered, the torque value of the main hoist motor at this moment is stored as the memory torque, and the brake is locked.

[0019] The beneficial effects of the present invention include: The pure electric power system of the present invention is suitable for using small motors, and the combination of small motors is used to meet the working requirements. Each motor has high working efficiency, saves energy, and avoids the problems of low working efficiency and energy waste caused by using large motors. The control method in this aspect realizes the anti-slip protection of the main hoist based on the judgment of the heavy object state. Therefore, the present invention improves the working condition adaptability of the electric rotary drilling rig, reduces energy consumption, and improves the system safety and reliability. Description of the Drawings

[0020] Figure 1 It is a structure diagram of the power system of a pure electric rotary drilling rig;

[0021] Figure 2 Structure schematic diagram of the main hoist system;

[0022] Figure 3 Safety control flow chart of the main hoist system;

[0023] Among them, 1. Construction site distribution box, 2. External cable, 3. On-vehicle rectifier cabinet, 4. Power battery, 5. Battery management system, 6. Motor controller, 7. Main hoist motor, 8. Power head motor, 9. Main pump motor, 10. Pump group, 11. Control valve group, 71. Brake, 72. Drum, 73. Steel rope, 74. Mast support frame, 75. Heavy object. Detailed implementation mode

[0024] Such as Figure 1 As shown, the power system of the pure electric rotary drilling rig of the present invention includes a DC bus. The DC bus is connected to the working motors through the motor controller 6. The working motors include the main hoist motor 7, the power head motor 8 and the main pump motor 9.

[0025] The power supply of the DC bus includes two paths. One path is the power battery 4. The power battery 4 is configured with a battery management system (BMS) 5, and the power battery 4 is connected to the DC bus. The other path is the external commercial power. The commercial power passes through the distribution box 1 (set on the construction site) and the on-vehicle rectifier cabinet (AC / DC) 3 and is connected to the DC bus, which is used to convert the alternating current of the power grid into direct current, and can also have the function of boosting or bucking the direct current.

[0026] The front end of the external cable 2 is connected to the distribution box (AC / AC) 1 to transmit the alternating current of the power grid to the on-vehicle rectifier cabinet 3 connected to the rear end. The power battery 4 and the battery management system 5 together form an on-vehicle energy supply system, which is connected in parallel with the on-vehicle rectifier cabinet 3 and connected to the DC bus to provide electrical energy to the motor controller 6. The motor controller 6 is an inverter device used to convert direct current into alternating current for the operation of the motor. The motor controller 6 can be an integrated multi-in-one controller or individual independent single motor controllers (for example, each motor is respectively configured with a motor controller).

[0027] Among them, the main hoist system is as Figure 2 As shown, the main hoist motor 7 is used to drive the main hoist 72. The main hoist 72 is wound with a steel rope 73. The steel rope 73 pulls the heavy object 75 through the mast support frame 74. The main hoist 72 also includes a brake 71. The brake 71 is arranged between the main hoist motor 7 and the main hoist 72 or integrated into the main hoist 72.

[0028] Among them, the power head motor 8 is used to drive the drill bit.

[0029] Among them, the main pump system includes a main pump motor 9, a pump set 10, etc. The main pump motor drives the pump set 10, and the pump set 10 is connected to a control valve group 11, and the control valve group 11 is connected to each hydraulic system operating component. Through the control valve group 11, the start, stop, and flow regulation of each hydraulic operating component can be achieved. In this embodiment, the power head, the main winch, etc. belong to the main operating components, so independent motors are respectively directly driven; for the above-mentioned hydraulic operating components, which are components that do not often operate, the method of using a motor to drive the hydraulic system is adopted to provide power.

[0030] Among them, the operating motors include not only the main winch motor 7, the power head motor 8, and the main pump motor 9, but also other types of operating motors can be added according to specific situations, such as a slewing motor, a traveling motor, etc. In addition, for a certain type of operating motor, it can be a single motor or include multiple motors, that is to say, different numbers of motors and arrangement methods can be selected. For example, in order to improve the drilling effect of the power head, a parallel dual-motor is used to drive the power head; in order to ensure the lifting and braking effect of the main winch for heavy objects, a series dual-motor is used to achieve this. In this embodiment, the motor is preferably a permanent magnet synchronous motor.

[0031] Among them, in this embodiment, the power battery is used as an on-vehicle power supply device. As other implementation manners, it can also be a super capacitor or other electric energy storage devices.

[0032] The pure electric power system of this embodiment is completely driven by electric energy and does not rely on other energy forms such as fossil fuels; and the electric energy supply includes two ways: commercial power and battery. Compared with a single way, the system has stronger safety and stability, and also improves the adaptability of the rotary drilling rig. For example, when connected to the power grid, the power grid is the main power supply way; when not connected to the power grid or the power that the power grid can provide is small, the battery is the main power supply way. In addition, the power battery can also recover the energy during the electric braking process (when the main winch motor lifts and lowers heavy objects such as drill pipes and drill buckets, the energy during the lowering process of the heavy objects can be recycled) to save energy.

[0033] The pure electric power system of this embodiment can implement various control strategies. The following introduces the safety control method of the main winch system.

[0034] The main winch system is as Figure 2As shown in the figure, a brake 71 is provided between the main hoist motor 7 and the main hoist 72 to restrict the steel rope 73. Different from the main pump providing pressurized power and the power head providing drilling driving power, the main hoist motor needs to provide timely response actions during the lifting and lowering of heavy objects. Especially in the emergency stop state, the hoist motor needs to maintain a short-term stop state before the mechanical brake is locked. During the operation of the rotary drilling rig, a failure or an emergency may occur that requires emergency braking, and then restart. After restarting, the steel rope may still bear the heavy object. For a non-electric power system, the mechanical or hydraulic system itself has a limiting ability, so that the steel rope can still maintain tension after restarting. However, the motor has no relevant control instructions after restarting. If the steel rope is still loaded, it may cause certain safety hazards.

[0035] To solve this problem, the idea of the present invention is to memorize the torque at this time when the machine stops, maintain the brake locked after the motor starts, and give the torque command to the motor equal to the memorized torque, so as to maintain the tension of the steel rope and ensure safety.

[0036] Specifically, as Figure 3 shown, the steps of the safety control method are as follows:

[0037] 1) The motor starts.

[0038] 2) The brake remains in the locked state.

[0039] 3) Judge whether the whole machine is powered on normally and receive the working speed command.

[0040] 4) If not, wait; if so, the main hoist motor performs torque control and reads the memorized torque at the last stop as the target torque; the so-called memorized torque is the torque value stored at the stop.

[0041] 5) The actual torque of the main hoist motor starts to increase, and judge whether the actual torque of the main hoist motor has increased to the target torque.

[0042] If not, that is, the torque of the main hoist motor can never increase to the target torque (possibly due to motor failure or other equipment failures), and it exceeds the set torque response period, then the motor stops; the so-called set torque response period is determined by the engineering designers according to the actual situation.

[0043] 6) If so, that is, the actual torque increases to the target torque within the set torque response period; at this time, request the brake to open.

[0044] 7) Judge whether the brake is opened, that is, confirm the brake state. If the brake is not opened within the set request period, continue to request the brake to open; the set request period is the time for confirmation and is determined by the engineering designers.

[0045] 8) Completion confirmation, that is, the brake is opened within the set request cycle. Due to the torque of the hoist motor, it can ensure that the heavy object does not slide down instantly when the brake is opened, thus ensuring safety. After the brake is opened, the hoist motor switches to speed control, responds to the normal target speed command, and works normally;

[0046] 9) During normal operation, when a shutdown command, hoist abnormal fault alarm or emergency braking is received, a brake locking request is sent, the torque value of the hoist motor at this moment is stored as the memory torque, and the brake locking is completed. During the process of the main hoist motor executing the target command, the judgment of shutdown execution, fault alarm, emergency braking light trigger signal is continuously carried out (for example, through an interrupt mechanism) to ensure the timely response to the braking demand; during the process of requesting to execute the target command, a response detection period is set respectively to cope with the system response processing process, and the execution of returning to the brake locking state for overdue or no command action is carried out;

[0047] 10) The motor restarts and starts again from step 1).

[0048] At each startup, due to the implementation of steps 3)-6), it can ensure that the heavy object does not slide down instantly when the brake is opened, avoiding the occurrence of safety accidents.

[0049] In summary, the pure electric power system of the present invention is suitable for using small motors, and meets the operation requirements through the combination of small motors. Each motor has high working efficiency, saves energy, and avoids the problems of low working efficiency and energy waste caused by using large motors. The control method in this aspect is based on the judgment of the heavy object state, realizing the anti-slip protection of the main hoist. Therefore, the present invention improves the working condition adaptability of the electric rotary drilling rig, reduces energy consumption, and improves the system safety and reliability.

Claims

1. A power system for a pure electric rotary drilling rig, characterized in that, including: a DC bus, the DC bus is connected to a working motor through a motor controller, and the working motor includes a main hoist motor, a power head motor and a main pump motor; two power supplies are connected in parallel to the DC bus, one includes a connected converter, the converter is used to connect to a distribution box through an external cable, and the distribution box is used to connect to the power grid; the other is a power battery, and the power battery is connected to the DC bus; wherein, the main hoist motor is used to drive the main hoist; the power head motor is used to drive the drill bit; the main pump motor is used to drive a pump set, and the pump set is connected to each hydraulic working component; wherein, when the whole machine is powered on normally and receives a working instruction, the main hoist motor performs torque control, and reads the torque value of the main hoist motor at the last shutdown as the target torque; the main hoist motor increases torque, when the torque reaches the target torque, it requests the brake to open; if the torque of the main hoist motor cannot be increased to the target torque and exceeds the set torque response period, the motor shuts down; after the brake is opened, the main hoist motor responds to the working instruction and works normally.

2. The power system of the pure electric rotary drilling rig according to claim 1, characterized in that, The converter is a vehicle-mounted rectifier cabinet, which is used to convert the alternating current of the external power grid into direct current.

3. The power system of the pure electric rotary drilling rig according to claim 1, wherein The motor controller is an all-in-one controller, or several independent motor controllers, and each motor controller is respectively connected to a working motor.

4. The power system of the pure electric rotary drilling rig according to claim 1, wherein The working motor further includes a slewing motor and a traveling motor.

5. The power system of the pure electric rotary drilling rig according to claim 1, characterized in that, Each type of working motor includes more than one motor.

6. The power system of the pure electric rotary drilling rig according to claim 1, characterized in that, The main hoist system includes a main hoist motor, a main hoist and a brake, the main hoist motor drives the main hoist, and the brake is arranged between the main hoist motor and the main hoist or integrated into the main hoist.

7. A control method for a power system of a pure electric rotary drilling rig according to any one of claims 1-6, characterized in that, The power system of a pure electric rotary drilling rig includes a DC bus, the DC bus is connected to a working motor through a motor controller, and the working motor includes a main hoist motor, a power head motor and a main pump motor; two power supplies are connected in parallel to the DC bus, one includes a connected converter, the converter is used to connect to a distribution box through an external cable, and the distribution box is used to connect to the power grid; the other is a power battery, and the power battery is connected to the DC bus; wherein, the main hoist motor is used to drive the main hoist; the power head motor is used to drive the drill bit; the main pump motor is used to drive a pump set, and the pump set is connected to each hydraulic working component; the steps of the control method include: when the whole machine is powered on normally and receives a working instruction, the main hoist motor performs torque control, and reads the memory torque at the last shutdown as the target torque; the main hoist motor increases torque, when the torque reaches the target torque, it requests the brake to open; if the torque of the main hoist motor cannot be increased to the target torque and exceeds the set torque response period, the motor shuts down; after the brake is opened, the main hoist motor responds to the working instruction and works normally; during the working process, when receiving a shutdown instruction, a main hoist abnormal fault alarm or triggering an emergency brake, the torque value of the main hoist motor at this moment is stored as the memory torque, and the brake is locked.

8. The control method of the power system of the pure electric rotary drilling rig according to claim 7, characterized in that, The converter is a vehicle-mounted rectifier cabinet, which is used to convert the alternating current of the external power grid into direct current.

9. The control method of the power system of the pure electric rotary drilling rig according to claim 7, characterized in that, The motor controller is an all-in-one controller, or several independent motor controllers, and each motor controller is respectively connected to a working motor.

10. The control method of the power system of the pure electric rotary drilling rig according to claim 7, characterized in that, The working motor further includes a slewing motor and a traveling motor.

11. The control method of the power system of the pure electric rotary drilling rig according to claim 7, characterized in that, Each of the operation motors includes more than one motor quantity.

12. The control method of the power system of the pure electric rotary drilling rig according to claim 7, characterized in that, The main hoisting system includes a main hoisting motor, a main hoist, and a brake. The main hoisting motor drives the main hoist, and the brake is provided between the main hoisting motor and the main hoist or integrated onto the main hoist.

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