Hybrid dual-mode drive fracturing pump skid system

Abstract

The application discloses an oil-electric dual-mode driving fracturing pump skid system, belongs to the technical field of skid-mounted equipment of oil and gas fracturing equipment, adopts a common DC bus architecture, and hangs a rectification power supply unit, an energy storage bidirectional converter and a plurality of variable frequency driving units on the bus to drive a permanent magnet synchronous motor to drive a fracturing pump. In control, the bus voltage and load power are detected, the energy storage unit is controlled to compensate or absorb power quickly to suppress the bus fluctuation caused by the impact load, and the rectification unit supports multi-source input to get rid of the dependence on a single power grid. Modular parallel variable frequency units are adopted to realize flexible power expansion, and the rotor flux orientation control is matched to improve the power factor. The application solves the problems of complete dependence on the power grid, severe bus fluctuation, low integration, fixed power and low power factor, and achieves the effects of reducing the power grid capacity demand, suppressing the bus voltage fluctuation within 5%, supporting plug-and-play expansion, and operating close to the unit power factor.

Description

Technical Field

[0001] This invention relates to the field of skid-mounted equipment technology for oil and gas fracturing equipment, specifically to a dual-mode driven fracturing pump skid system that can be used for both oil and electricity. Background Technology

[0002] Electric fracturing (EFL) equipment is a key component in shale oil and gas and tight oil and gas development. It is used to inject fracturing fluid under high pressure into the formation to create artificial fractures and improve oil and gas recovery. With the increasing intensity of unconventional oil and gas exploration and development, EFL equipment is being used more and more due to its environmental friendliness and high-capacity operation. Currently, the power supply architecture, drive system, and equipment integration method of EFL equipment directly affect the energy consumption cost, operational efficiency, environmental adaptability, and ease of on-site deployment in fracturing operations.

[0003] Currently, patent application CN118793418A discloses an electrically driven fracturing pump injection device and its power supply system. The device includes multiple electrically driven fracturing pump injection units, each mounted on a pure electric heavy-duty chassis. Each unit is connected to a switchgear via a DC bus, and the switchgear is connected to one end of a transformer-rectifier unit via the DC bus. The other end of the transformer-rectifier unit is connected to an external high-voltage power supply. Each electrically driven fracturing pump injection unit includes an energy storage unit, a variable frequency integrated motor, a drive shaft, and a fracturing pump. The energy storage unit is connected to both the pure electric heavy-duty chassis and the variable frequency integrated motor via cables. The energy storage unit contains interconnected battery packs, a BMS management system, and a charging unit. During fracturing operations, the external high-voltage power supply is converted to DC power by the transformer-rectifier unit and delivered to the DC bus to power the variable frequency integrated motor. The energy storage unit is mounted on the DC bus as a supplementary power source.

[0004] However, the existing electrically driven fracturing pumping equipment still has the following shortcomings in practical applications: The equipment is highly dependent on the external power grid and cannot operate without it. Existing electric fracturing pumps and their power supply systems rely entirely on external high-voltage power sources, with a single energy source: a transformer and rectifier unit converts AC power from the external grid into DC power to supply the variable frequency motor. When fracturing well sites are located in remote mountainous or hilly areas without grid coverage, the equipment cannot operate normally, severely limiting its widespread application. Although energy storage units can provide emergency power during grid failures, their limited capacity cannot support high-power, long-duration fracturing operations; they can only be used as short-term backup power and lack independent self-generating capabilities.

[0005] The impact load of fracturing pumps causes drastic fluctuations in bus voltage, affecting system stability. Fracturing pumps exhibit typical impact load characteristics during start-up, shutdown, pressurization, and depressurization, with rapidly changing load power. While existing energy storage units are connected to the DC bus, their control strategies primarily rely on simple power replenishment, lacking rapid response and mitigation mechanisms for load fluctuations. When the load suddenly increases, the bus voltage drops sharply, potentially causing the variable frequency drive (VFD) motor to shut down due to undervoltage protection; conversely, when the load suddenly decreases, the bus voltage rises sharply, potentially causing overvoltage damage to electrical equipment and severely impacting system reliability.

[0006] The equipment suffers from low integration, resulting in high on-site deployment and relocation costs. While existing electric fracturing pump injection equipment and unit power supply systems integrate frequency conversion functions into the variable frequency motor, the entire electric drive system still requires independent transformer and rectifier units, switchgear, and other equipment. This leads to a large number of devices, a large footprint, and a significant workload for on-site installation, cable connection, and commissioning. Furthermore, although the equipment is mounted on a pure electric heavy-duty chassis, its large size and weight make deployment and transportation extremely difficult in mountainous or hilly areas where available space is limited.

[0007] The power supply capacity has poor scalability and cannot flexibly adapt to fracturing conditions with different power levels. In existing technologies, each electrically driven fracturing pump is equipped with one variable frequency integrated motor and one fracturing pump, and the drive power of a single unit is fixed. When fracturing operations require higher power, the power capacity can only be increased by adding more electrically driven fracturing pumps. It is not possible to flexibly adjust the drive power configuration at the level of a single unit, making it difficult to meet the diverse drive power requirements of different well conditions and fracturing processes.

[0008] The motor has low energy efficiency, resulting in high energy costs during long-term operation. Current technology uses variable frequency integrated motors, but does not explicitly employ permanent magnet synchronous technology. Conventional variable frequency integrated motors are mostly asynchronous motors, with low power factors and poor low-speed torque characteristics. This leads to low efficiency under heavy-load, low-speed conditions in fracturing pumps, significantly increasing long-term energy costs.

[0009] Therefore, there is an urgent need for a dual-mode drive fracturing pump skid system that is self-generating, can operate independently off the power grid, has stable bus voltage, is highly integrated, and has high motor energy efficiency, in order to overcome the shortcomings of the existing technologies. Summary of the Invention

[0010] The purpose of this invention is to provide a dual-mode drive fracturing pump skid system that can be used for both oil and electricity, solving the problems of existing electric fracturing equipment that rely entirely on external power grids, suffer from severe fluctuations in DC bus voltage due to the impact load of the fracturing pump, have low equipment integration, have fixed drive power for a single unit, and have low power factor due to the use of asynchronous motors.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A dual-mode drive fracturing pump skid system for both oil and electricity use includes: A power generation matrix unit, comprising multiple generator sets, is used to generate alternating current in the absence of an external power source. An AC combiner unit is optionally connected to the power generation matrix unit and an external AC power source, and is used to combine a selected AC power source. A rectifier unit, connected to the AC combiner unit, is used to convert AC power into DC power; A DC power distribution unit, which is connected to the rectifier unit to form a DC bus; An energy storage unit is connected in parallel to the DC bus to smooth out load fluctuations. A drive motor, which is connected to the DC bus, is used to convert electrical energy into mechanical energy; A fracturing pump, which is connected to the drive motor, is used to pressurize the fracturing fluid; The control unit is connected to the power generation matrix unit, the rectifier unit, the energy storage unit, and the drive motor via signals, and is used to control the coordinated operation of each unit.

[0012] Preferably, each generator set in the power generation matrix unit is equipped with a generator controller, and the DC output terminal of each generator controller is connected in parallel to the DC bus to realize the parallel grid connection of multiple generators on the DC side.

[0013] Preferably, the energy storage unit includes a battery pack and a battery management system. The battery management system is used to monitor the status of the battery pack and control the charging and discharging of the battery pack according to the instructions of the control unit, so as to smooth out voltage fluctuations of the DC bus.

[0014] Preferably, the drive motor is a permanent magnet synchronous motor, which integrates an inverter drive unit. The inverter drive unit is used to convert the DC power from the DC bus into AC power to drive the permanent magnet synchronous motor.

[0015] Preferably, there are multiple drive motors, each connected to the DC bus via an independent motor controller, and the outputs of the multiple drive motors are coupled together through a confluence mechanism to drive the fracturing pump.

[0016] Preferably, the control unit dynamically calculates the allocated power of each generator set according to the load power demand, and issues power commands to each generator set respectively, so that each generator set operates according to the allocated power.

[0017] Preferably, when the load power is lower than a preset threshold, the control unit controls part of the generator set to stop operating, while the remaining generator sets operate in the high-efficiency range.

[0018] Preferably, the AC combiner unit is provided with a switching switch, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal is connected to the power generation matrix unit, the second input terminal is used to connect to an external AC power source, and the switching switch is used to selectively connect the first input terminal or the second input terminal to the output terminal.

[0019] Compared with the prior art, the beneficial effects of the present invention are: This invention solves the limitation of relying entirely on external power grid for power supply by constructing a common DC bus architecture and integrating a bidirectional energy storage converter, enabling the power grid and energy storage to work together and complement each other to supply power, and reducing the capacity requirements of the external power grid.

[0020] By utilizing the energy storage unit for rapid power tracking and dynamic compensation of the impact load of the fracturing pump, the problem of severe fluctuations in DC bus voltage is solved, and the dynamic fluctuations in bus voltage are suppressed to within 5%, ensuring the stable operation of each unit.

[0021] By modularly connecting rectification, energy storage, and frequency conversion drive to the busbar, the problem of low equipment integration is solved, which simplifies the power distribution structure and significantly saves floor space.

[0022] By using multiple variable frequency drive units connected in parallel, the problem of fixed power of a single drive unit is solved, enabling flexible power expansion and adaptation to different fracturing conditions.

[0023] By replacing the asynchronous motor with a permanent magnet synchronous motor and combining it with vector control, the problem of low power factor is solved, making the power factor close to unity power factor and significantly reducing line loss. Attached Figure Description

[0024] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a layout diagram of the entire machine according to Embodiment 1 of the present invention.

[0025] Figure 2 This is another perspective view of the overall layout of Embodiment 1 of the present invention.

[0026] Figure 3 This is a layout diagram of the entire machine according to Embodiment 2 of the present invention.

[0027] Figure 4 This is another perspective view of the overall layout of the machine in Embodiment 2 of the present invention.

[0028] Figure 5This is a schematic diagram of the overall system topology of Embodiment 1 of the present invention.

[0029] Figure 6 This is a schematic diagram of the overall system topology in Embodiment 2 of the present invention.

[0030] Figure 7 This is a schematic diagram of the overall system topology and a communication topology diagram of the present invention.

[0031] Figure 8 This is a block diagram of the dual power supply switching logic of the present invention.

[0032] Icons: 1-Power generation matrix unit, 2-Energy storage unit, 3-Generator controller, 4-Range extender controller, 5-Drive motor, 6-Coupling, 7-Control cabinet, 8-Skirt, 9-Fracturing pump, 10-Gearbox, 11-600V AC combiner unit, 12-High voltage DC power distribution unit, 13-Power combiner box, 14-Motor control unit, 15-Generator set, 16-Dual AC transfer switch, 17-Cooling system, 18-DC / DC auxiliary power supply, 19-Auxiliary control load, 20-800V high voltage DC bus, 21-600VAC external power input. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example 1 Please refer to Figure 1 , 2 5. This embodiment provides a dual-mode drive fracturing pump skid system for both oil and electricity, including a power generation matrix unit 1, an energy storage unit 2, a generator controller 3 (GCU), a range extender controller 4 (RCU), a drive motor 5, a coupling 6, a control cabinet 7, a skid base 8, a fracturing pump 9, a gearbox 10, a 600V AC combiner unit 11, and a high-voltage DC power distribution unit 12 (PDU).

[0035] The skid 8 is a frame structure used to support and secure the various components. The power generation matrix unit 1 is arranged side-by-side on one side of the skid 8 and consists of multiple generator sets 15. Each generator set includes an internal combustion engine and an AC generator coaxially driven with it. The internal combustion engine can be a diesel engine, a natural gas engine, or a methanol engine. The generator sets output 600V AC power.

[0036] A 600V AC combiner unit 11 is mounted on a skid mount 8. Its input terminals are connected to the output terminals of each generator set in the power generation matrix unit 1 and the on-site 600V industrial mains interface. The 600V AC combiner unit 11 has a built-in dual-channel AC transfer switch. This transfer switch has a first input terminal, a second input terminal, and an output terminal. The first input terminal is connected to the output terminal of the power generation matrix unit 1, the second input terminal is connected to the on-site 600V industrial mains, and the output terminal is connected to the generator controller 3. The transfer switch is used to selectively connect either the first or second input terminal to the output terminal. Electrical and mechanical interlocks are installed between the two power supplies to prevent simultaneous grid connection.

[0037] The input terminal of the generator controller 3 (GCU) is connected to the output terminal of the 600V AC combiner unit 11 to rectify and boost the input 600V AC power to 800V high-voltage DC power. The number of generator controllers 3 matches the number of generator sets 15 in the generator matrix unit 1, and the DC output terminal of each generator controller 3 is connected in parallel to the 800V high-voltage DC bus 20.

[0038] The range extender controller 4 (RCU) is connected to the generator controller 3 and the generator matrix unit 1. It is used to receive power dispatching commands from the vehicle controller VCU, control the internal combustion engine and the generator controller 3, and enable the generator set to operate stably in the high-efficiency power generation range.

[0039] The high-voltage DC distribution unit 12 (PDU) is mounted on the skid 8, and its input terminal is connected to the 800V high-voltage DC bus 20. The high-voltage DC distribution unit 12 is equipped with a high-voltage DC relay, fuse, busbar, high-voltage insulation monitoring device and DC / DC auxiliary power supply 18, which are used to realize high-voltage power distribution, electrical conversion and fault protection.

[0040] Energy storage unit 2 is connected in parallel to the 800V high-voltage DC bus 20. Energy storage unit 2 consists of an energy storage battery or supercapacitor, a BMS management system, a liquid cooling heat dissipation device, and a high-voltage distribution box. The nominal voltage of energy storage unit 2 is 800V, used to smooth out the high-power load fluctuations caused by the start-up, shutdown, pressurization, and depressurization of fracturing pump 9, thereby shaving peaks and filling valleys and stabilizing the bus voltage.

[0041] The drive motor 5 is a permanent magnet synchronous motor, and its input terminal is connected to one of the 800V DC outputs of the high-voltage DC power distribution unit 12. The permanent magnet synchronous motor integrates an inverter drive unit and a water-cooling structure. The inverter drive unit converts the 800V DC power into AC power to drive the permanent magnet synchronous motor. The output shaft of the permanent magnet synchronous motor is connected to the reduction gearbox 10 via a coupling 6, and after reduction and torque amplification, drives the fracturing pump 9.

[0042] Control cabinet 7 integrates the vehicle main control unit (VCU) and PLC control system. The VCU is the core of the entire system, communicating with the controllers of each subsystem via the CAN bus to achieve overall machine operation coordination, operating mode management, energy logic decision-making, fault diagnosis, and safety protection. The PLC interacts with the VCU via the bus, issuing control commands to the VCU according to the fracturing process, and realizing data communication and human-machine interaction with the host computer and field instruments.

[0043] Please refer to Figure 5 The overall system topology and working principle of this embodiment are as follows: The power generation matrix unit 1 consists of multiple generator sets 15 connected in parallel to output 600V AC power, serving as the main power source when there is no external power supply. The 600V AC combiner unit 11 is equipped with a dual-path switching switch 16, enabling power selection between the generator circuit and the mains input circuit, with double interlocks preventing simultaneous grid connection. The generator controller (GCU) 3 rectifies and boosts the 600V AC power to 800V high-voltage DC power and connects it to the 800V high-voltage DC bus 20, providing rectification and voltage regulation functions. The high-voltage DC distribution unit (PDU) 12 performs high-voltage DC combiner, distribution, insulation monitoring, fault protection, and overall power-on / off management. The cooling system 17 adopts a combined air-cooled and liquid-cooled structure to maintain constant temperature for heat-generating components such as the generator sets 15, generator controller (GCU) 3, and permanent magnet integrated motor. The DC / DC auxiliary power supply 18 converts the high-voltage DC power to 24V. Low-voltage electricity supplies power to the control system and low-voltage components; the energy storage unit 2 is connected in parallel to the 800V DC bus to achieve load peak shaving and valley filling and stabilize the bus voltage; the 800V DC bus provides power to the energy storage, auxiliary power supply, permanent magnet integrated motor and other high-voltage loads; VAC external power input 21 is the on-site industrial mains power access interface, which, together with the switch, enables dual-mode power supply selection.

[0044] The working process of this embodiment is as follows: Mode 1: Pure power generation mode (no external 600V AC power) When there is no 600V industrial mains power on site, the operator switches the power supply circuit to the power generation matrix unit 1 circuit via the switch of the 600V AC combiner unit 11. The VCU calculates the required total power generation based on the load demand of the fracturing pump 9 and issues power commands to each range extender controller 4 according to the principle of average distribution. Each range extender controller 4 controls the corresponding internal combustion engine to start, driving the alternator to operate and output 600V AC power.

[0045] The 600V AC power output from each generator set is combined by the 600V AC combiner unit 11 and then sent to each generator controller 3. Each generator controller 3 rectifies and boosts the 600V AC power to 800V high-voltage DC power, and the DC output terminals of each generator controller 3 are connected in parallel to the 800V high-voltage DC bus 20. The high-voltage DC power distribution unit 12 distributes the 800V DC power to the permanent magnet synchronous motor.

[0046] The inverter drive unit inside the permanent magnet synchronous motor converts 800V DC power into controllable AC power to drive the permanent magnet synchronous motor. The motor output shaft drives the fracturing pump 9 via coupling 6 and gearbox 10. During the start-up, shutdown, and sudden load changes of the fracturing pump 9, the energy storage unit 2 responds in real time. When the load suddenly increases, the energy storage unit 2 releases electrical energy to supplement the bus voltage; when the load suddenly decreases, the energy storage unit 2 absorbs excess electrical energy, maintaining the 800V DC bus voltage stable within ±5%.

[0047] Mode 2: External AC power direct drive mode (connected to 600V industrial AC power) When 600V industrial mains power is available on site, the operator switches the power supply circuit to the mains input circuit via the switch of the 600V AC combiner unit 11, while simultaneously blocking the output of the generator matrix unit 1. The 600V industrial mains power is sent to the generator controller 3 via the 600V AC combiner unit 11, rectified and boosted to 800V high-voltage DC, and then connected to the 800V high-voltage DC bus 20 to power the permanent magnet synchronous motor. At this time, the generator set of the generator matrix unit 1 can be shut down and put into hibernation mode, realizing low-cost power supply operation from the external power grid.

[0048] Example 2 Please refer to Figure 3 , 4 6. The difference between this embodiment and embodiment 1 is that the driving scheme adopts a multi-motor combined linkage driving method, rather than a single permanent magnet synchronous integrated motor driving.

[0049] In this embodiment, the drive motor 5 uses multiple permanent magnet synchronous motors, each of which is connected to the high-voltage DC power distribution unit 12 via an independent motor control unit 14 (MCU). The input terminal of each motor control unit 14 (MCU) is connected to the 800V high-voltage DC bus 20, and the output terminal is connected to the corresponding permanent magnet synchronous motor. The output terminals of each permanent magnet synchronous motor are coupled through the combiner box 13 to jointly drive the fracturing pump 10.

[0050] The CAN bus is used to uniformly schedule the speed and torque of each motor controller (VCU). The synchronization control algorithm ensures that each permanent magnet synchronous motor operates at the same speed and with balanced output, so as to drive the load smoothly.

[0051] In this embodiment, the power rating of the permanent magnet synchronous motor is 300kW to 600kW, and 2 to 4 permanent magnet synchronous motors can be selected to combine according to the actual power requirements. When different power ratings are required, the power can be expanded simply by increasing or decreasing the number of permanent magnet synchronous motors, without the need to redesign the entire drive system.

[0052] Please refer to Figure 6 The overall system topology and working principle of this embodiment are as follows: Similar to Example 1, the difference is that multiple motor control units (MCUs) 14 are used at the back end to drive the corresponding permanent magnet synchronous motors respectively. The multiple motors are coupled through a confluence box to drive the fracturing pump. The VCU uniformly and synchronously controls the speed and torque of each motor control unit (MCU) 14 to ensure the smooth operation of multiple machines in coordination.

[0053] Example 3 Please refer to Figure 7 The working principle of the communication system topology in this embodiment is as follows: The VCU (Variable Restricted Unit) acts as the master node, interacting with various subsystems such as the Range Extender Controller (RCU), Generator Controller (GCU), Battery Management Unit (BMS), and Motor Control Unit (MCU) via the CAN bus network. It coordinates the operating modes, power distribution, and fault protection of all subsystems, achieving coordinated control of the entire machine. Simultaneously, it communicates with the PLC and host computer via Ethernet to achieve overall machine control and data exchange.

[0054] The communication system adopts a dual-layer architecture of Ethernet + CAN bus to achieve real-time performance, reliability, and scalability of the whole machine control. The structure and working principle are as follows: 1. Network hierarchy ; 2. Core Communication Link Upper-level monitoring link: host computer → PLC → parameter control unit (VCU), using Ethernet protocol to realize control parameter distribution, operation data upload, fault diagnosis and remote monitoring.

[0055] Mid-level main control link: The VCU, as the CAN bus master node, communicates with all sub-units through the CAN bus (main network) and is the "central channel" for the control of the whole machine.

[0056] Lower-level device link: Each sub-unit achieves closed-loop control of the device through an independent CAN / bus, and then interacts with the VCU through the main network.

[0057] 3. Communication connection instructions for each subsystem ; Example

[0058] Please refer to Figure 1-8 This embodiment provides a detailed description of the dual power supply switching control method.

[0059] The system supports two independent operating modes: diesel generator power and 600VAC mains power. It operates manually, with both power sources equipped with electrical and software interlocks to prevent simultaneous grid connection. Power switching operations are only permitted before equipment shutdown and formal operation commences. The switching function is locked during equipment operation under load to eliminate the risk of switching while energized.

[0060] (1) Shutdown status confirmation and global self-test The operator may initiate a switching operation only when the equipment is completely shut down and under no load. The VCU monitors the insulation performance of the high-voltage circuit, the contactor status, and overall fault alarm signals. If a short circuit, grounding, insulation abnormality, or device fault is detected, the system locks the switching function and outputs a fault message, prohibiting further operation.

[0061] (2) Manually select the power supply mode before operation. Operators manually select the target power supply mode via the local panel or host computer: generator power supply mode or mains power supply mode. The system immediately performs a hardware and software interlock check to confirm that the non-target power supply circuit is completely tripped and locked.

[0062] (3) Switch from mains power to diesel generator power supply The VCU sends a trip command to the high-voltage DC distribution unit 12 to disconnect the main contactor on the mains side. After a system delay of ≥50ms, the mains circuit is confirmed to be completely disconnected through position feedback. The generator side main contactor is then closed. The diesel generator set is started. After the generator set output voltage and frequency stabilize within the rated range, the generator controller 3 connects to AC power and performs rectification and voltage regulation to establish a stable 800V DC bus.

[0063] (4) Switching from diesel generator power supply to mains power supply The VCU sends a trip command to the high-voltage DC power distribution unit 12 to disconnect the main contactor on the diesel generator side; after a system delay of ≥50ms, it confirms that the generator circuit is completely disconnected; after the mains voltage and frequency parameters are found to be qualified, it closes the mains contactor on the mains side; the generator controller 3 rectifies the mains power to maintain the normal output of the 800V DC bus and completes the mode switching. Example

[0064] This embodiment provides a detailed description of the control method for parallel power generation of multiple generators.

[0065] The system achieves stable parallel operation of multiple machines, dynamic power distribution, steady-state efficiency optimization, and fault-safe exit through centralized control of VCU and independent execution of each RCU.

[0066] (1) Generator single-unit start-up and self-test The VCU issues a generator start-up command based on load demand. Each range extender controller 4 independently executes the generator start-up process, sequentially performing self-checks on key parameters such as oil pressure, coolant temperature, engine speed, DC output voltage, current, and insulation status. After all self-checks are passed, the RCU sends a signal indicating that the DC output is stable, fault-free, and ready for grid connection to the generator controller 3 and the VCU, entering the DC grid-connected ready state.

[0067] (2) Power distribution among generator sets The VCU communicates with each generator controller 3 via CAN. Based on the principle of average distribution or equal incremental rate, and combined with the current total load demand of the fracturing pump, it dynamically calculates and issues the target output power command for each generator. After receiving the command, the RCU adjusts the engine speed and generator excitation in a closed loop to precisely control the DC output power of the unit, so that the load rate of each unit is basically consistent and the output is balanced.

[0068] The VCU monitors the total power of the motor controller and the total power of the auxiliary system in real time, performs DC-side power balance control, and ensures that the total power generation = load power + energy storage charging and discharging power, thereby maintaining the stability of the 800V bus voltage.

[0069] Total power output of load : ; In the formula: —Total output power of load —Motor controller power —Number of motor drivers, for permanent magnet synchronous integrated machine solution, n=1 —Auxiliary equipment power, including heat dissipation, lubrication, heating, control, lighting, etc. ; In the formula: —Generator power output —Number of generators (3) Steady-state efficiency optimization When the load is below the preset threshold for an extended period (according to a set time or plan), the VCU will suspend 1-2 generator sets, while the remaining generator sets will operate in the high-efficiency range (70%-90% load rate) to reduce fuel consumption under low load; at the same time, it will continuously monitor the DC bus voltage and maintain it in the optimal range.

[0070] (4) Shutdown of faulty units and smooth transfer of load When a generator experiences overvoltage, overcurrent, overtemperature, or abnormal speed, the RCU reports to the VCU in real time; the faulty unit's DC grid-connected circuit is immediately disconnected to isolate the fault; the VCU redistributes power according to the remaining unit capacity to complete a smooth load transfer; if the total capacity of the remaining units is insufficient to support the load, the system controls the fracturing pump to gradually reduce the load to ensure the safety and stability of the entire unit. Example

[0071] This embodiment provides a detailed description of the smoothing control of energy storage unit 2.

[0072] Energy storage unit 2 consists of a battery pack, a BMS management system, a liquid cooling system, and a high-voltage distribution box. The battery pack has a nominal voltage of 800V and is connected in parallel to the 800V high-voltage DC bus 20 through the high-voltage distribution box. The BMS management system collects the battery pack's voltage, current, SOC (state of charge), and temperature in real time and interacts with the VCU via the CAN bus.

[0073] The VCU incorporates load prediction and power smoothing algorithms. When it predicts that the fracturing pump 9 is about to start or pressurize, the VCU sends a discharge command to the energy storage unit 2 in advance. The energy storage unit 2 releases electrical energy to replenish the bus voltage and avoid a sudden drop in bus voltage. When it predicts that the fracturing pump 9 is about to depressurize or stop, the VCU sends a charging command to the energy storage unit 2 in advance. The energy storage unit 2 absorbs excess electrical energy and avoids a sudden rise in bus voltage.

[0074] The energy storage unit 2 has a response time of less than 50ms, which can quickly track the impact load changes of the fracturing pump and control the voltage fluctuation of the 800V DC bus within ±5%.

[0075] The complete operating procedure of this system in well sites without external power is as follows: The fracturing team transported the system to the fracturing well site, which was not covered by the power grid, and positioned the skid mount 8. The operators checked the connection status of each component and confirmed that the switch of the 600V AC combiner unit 11 was in the generator matrix circuit position. Each generator set in the generator matrix unit 1 was started, and after passing self-tests, each unit entered the grid-connected ready state.

[0076] The VCU calculates the required total drive power based on the displacement and pressure required by the fracturing process and distributes power commands to each range extender controller 4. Each generator set outputs 600V AC power according to the command, which is rectified and stepped up to 800V DC power by the generator controller 3 and connected to the DC bus. The energy storage unit 2 is in standby mode, ready to respond to load fluctuations at any time.

[0077] The operator issues fracturing operation commands through the PLC control system. The VCU controls the permanent magnet synchronous motor to start, which drives the fracturing pump 9 through coupling 6 and gearbox 10. Fracturing fluid enters the fracturing pump 9 from the suction manifold, is pressurized, and then discharged from the discharge manifold into the formation.

[0078] During fracturing operations, the VCU monitors load power changes in real time and dynamically adjusts the output power of each generator set. When the load suddenly increases, energy storage unit 2 automatically discharges to replenish electrical energy; when the load suddenly decreases, energy storage unit 2 automatically charges to absorb excess electrical energy. At the same time, the VCU continuously monitors the operating status of each generator set. If a generator set malfunctions, the VCU automatically disconnects it and redistributes power to the remaining units.

[0079] After the fracturing operation is completed, the operator controls the fracturing pump 9 to stop via PLC, and the VCU controls each generator set to stop sequentially. If the next well site has 600V industrial mains power, the operator can switch the 600V AC combiner unit 11 to the mains input circuit while the system is stopped, and the system can then operate in external mains power supply mode.

[0080] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A dual-mode driven fracturing pump skid system for both oil and electricity, characterized in that: include: A power generation matrix unit, comprising multiple generator sets, is used to generate alternating current in the absence of an external power source. An AC combiner unit is optionally connected to the power generation matrix unit and an external AC power source, and is used to combine a selected AC power source. A rectifier unit, connected to the AC combiner unit, is used to convert AC power into DC power; A DC power distribution unit, which is connected to the rectifier unit to form a DC bus; An energy storage unit is connected in parallel to the DC bus to smooth out load fluctuations. A drive motor, which is connected to the DC bus, is used to convert electrical energy into mechanical energy; A fracturing pump, which is connected to the drive motor, is used to pressurize the fracturing fluid; The control unit is connected to the power generation matrix unit, the rectifier unit, the energy storage unit, and the drive motor via signals, and is used to control the coordinated operation of each unit.

2. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: Each generator set in the power generation matrix unit is equipped with a generator controller, and the DC output terminal of each generator controller is connected in parallel to the DC bus to realize the parallel grid connection of multiple generators on the DC side.

3. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: The energy storage unit includes a battery pack and a battery management system. The battery management system is used to monitor the status of the battery pack and control the charging and discharging of the battery pack according to the instructions of the control unit, so as to smooth out voltage fluctuations of the DC bus.

4. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: The drive motor is a permanent magnet synchronous motor, which integrates an inverter drive unit. The inverter drive unit is used to convert the DC power from the DC bus into AC power to drive the permanent magnet synchronous motor.

5. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: The number of drive motors is multiple, and each drive motor is connected to the DC bus through an independent motor controller. The outputs of the multiple drive motors are coupled together through a confluence mechanism to drive the fracturing pump.

6. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: The control unit dynamically calculates the allocated power of each generator set according to the load power demand, and issues power commands to each generator set so that each generator set operates at the allocated power.

7. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 6, characterized in that: When the load power is lower than a preset threshold, the control unit controls some of the generator sets to stop operating, while the remaining generator sets operate in the high-efficiency range.

8. The dual-mode drive fracturing pump skid system for both oil and electricity as described in claim 1, characterized in that: The AC combiner unit is equipped with a switching switch, which has a first input terminal, a second input terminal, and an output terminal. The first input terminal is connected to the power generation matrix unit, and the second input terminal is used to connect to an external AC power source. The switching switch is used to selectively connect the first input terminal or the second input terminal to the output terminal.

Images