Vehicle-mounted high-power electric drive system and control method thereof

Abstract

This invention relates to the field of electric drive control technology for high-pressure, high-displacement pumps in oilfield fracturing operations. It discloses a vehicle-mounted high-power electric drive system. The high-voltage power distribution unit is connected to the power input unit and consists of a load switch and a circuit breaker connected in series. The load switch is connected to a fuse to output low-voltage control power. The circuit breaker is sequentially connected to a phase-shifting transformer and a medium-voltage frequency converter to provide the main power supply for the medium-voltage motor of the fracturing pump. The input terminal of the pre-charge unit is connected to the load switch, and the output terminal is connected to the phase-shifting transformer. A cooling system provides cooling for the phase-shifting transformer and the medium-voltage frequency converter. This invention also discloses a control method for the vehicle-mounted high-power electric drive system. This vehicle-mounted high-power electric drive system and its control method enable the integrated vehicle-mounted operation of a high-power, high-displacement fracturing pump skid and its drive system in the fracturing engineering field, significantly reducing on-site work intensity, lowering operating costs, and mitigating on-site risks.

Description

Technical Field

[0001] This invention relates to the field of electric drive control technology for high-pressure, high-displacement pumps in oilfield fracturing operations, specifically to a vehicle-mounted high-power electric drive system and its control method. Background Technology

[0002] With technological advancements, the application of electrification in oil and gas equipment is gradually increasing. In China and North America, fracturing equipment is gradually entering the era of electrification, and high-power electric drive systems are the core equipment in this wave of electrification.

[0003] Currently, the electric drive equipment used in fracturing engineering both domestically and internationally is mainly skid-mounted. The application scenario involves first using trailers to transport the electric drive system and fracturing pump to the oil and gas field well site in batches. After the equipment arrives at the well site, heavy lifting equipment is used to place the equipment into fixed positions one by one. Then, workers lay cables and cable trays, connect wires, and after construction is completed, the corresponding materials are disassembled and packed before being moved to the next work site. The entire preparation process often lasts for dozens of days. Frequent handling, hoisting, and disassembly are the most prominent characteristics of current electric drive equipment used in fracturing engineering. This greatly reduces the efficiency of fracturing construction and results in serious waste of equipment energy consumption. Furthermore, this operation mode artificially increases the number of high-risk areas at the construction site, bringing many uncertainties.

[0004] In existing technologies, the separate design of the electric drive system and the pump skid system leads to multiple hoisting operations, long-distance high-voltage cable laying and cable tray installation, and the coexistence of multiple risk areas such as high-pressure liquids and high-pressure electrical systems. This results in long construction preparation cycles, high work intensity, high costs, and high risks. Therefore, there is an urgent need for a vehicle-mounted high-power electric drive system and its control method that can achieve rapid deployment, reduce on-site operational risks, and improve construction efficiency. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the aforementioned technologies by providing a vehicle-mounted high-power electric drive system and its control method. This system enables the integrated vehicle-mounted high-power, high-displacement fracturing pump skid and its drive system in the field of fracturing engineering, significantly reducing on-site work intensity, lowering operating costs, and mitigating on-site risks.

[0006] To achieve the above objectives, the vehicle-mounted high-power electric drive system designed in this invention includes a power input unit, a high-voltage power distribution unit, a pre-charge unit, a phase-shifting transformer, a medium-voltage frequency converter, a cooling system, and a control unit. The power input unit is electrically connected to the output terminal of the well site power supply equipment switch. The high-voltage power distribution unit is connected to the power input unit and consists of a load switch and a circuit breaker connected in series. The load switch is connected to a fuse to output low-voltage control power. The circuit breaker is sequentially connected to the phase-shifting transformer and the medium-voltage frequency converter to provide the main power supply for the medium-voltage motor of the fracturing pump. The input terminal of the pre-charge unit is connected to the load switch, and the output terminal is connected to the phase-shifting transformer. The cooling system provides cooling for the phase-shifting transformer and the medium-voltage frequency converter. The control unit is electrically connected to the high-voltage power distribution unit, the medium-voltage frequency converter, and the cooling system, respectively, and realizes fully automatic control and protection of the system through the control unit.

[0007] Preferably, the power input unit adopts 10KV input, the system capacity is configured to be no less than 5800KVA, the single-unit drive power is no less than 4500kW / 3.3KV, the system size is no greater than 4750mm×2500mm×2300mm, the overall weight is no greater than 13.5T, the whole machine is installed on the gooseneck platform of the trailer, and the overall height after installation is no greater than 4 meters. The fracturing pump skid is installed on the rear trailer platform. The 10KV high voltage is connected to the system through the side, and after passing through the switch cabinet, phase shift transformer and medium voltage frequency converter, it is directly connected to the medium voltage motor of the fracturing pump installed on the trailer by cable. The pump skid and electric drive system are integrated into the trailer, which basically eliminates the risk of hoisting heavy equipment at the well site, and reduces the construction site area requirement by more than 30% and the equipment relocation and transportation work by more than 40%. This greatly lowers the threshold of fracturing construction operations, improves mobility, and realizes that fracturing and production enhancement operations in oil and gas field development can be used as needed and left as soon as they are completed, which greatly improves the construction efficiency of oil well fracturing and production enhancement operations.

[0008] Preferably, due to the system's lightweight design, the pre-charging unit, high-voltage bypass system, phase-shifting transformer, and high-voltage control components are all installed bare in the main power transformer room. Since the main transformer room has a relatively large capacity, it is necessary to maintain the system's airflow while ensuring overall high protection. Therefore, a multi-stage progressive air duct design is adopted, including four layers of protection: the first layer is the louvers on the outer wall of the cabin to prevent larger foreign objects (over 2.5cm) from entering; the second layer is a double-detour structure, which adjusts the air duct direction after air intake to create conditions for larger dust particles to settle; the third layer is a 5µm filter for initial mass filtration of the incoming air; and the fourth layer is a 1µm filter for fine mass filtration of the incoming air. Pre-set air duct buffer zones between different protection levels directly avoid direct contact between the structures of different protection layers. This not only effectively increases the air intake area but also further reduces the system's air intake pressure, decreases the intake of foreign objects, and reduces maintenance workload.

[0009] Preferably, the cooling system includes an air-cooled system and a water-cooled system, wherein the air-cooled system provides cooling for the phase-shifting transformer and the water-cooled system provides cooling for the medium-voltage frequency converter.

[0010] Preferably, the medium-voltage frequency converter adopts an NPC three-level structure, with separate designs for the rectifier and inverter units. The rectifier and inverter units are mounted on a high-conductivity hot water cooling plate. The water cooling system employs an internal and external dual-circulation structure, with completely separate internal and external circulation channels. The internal circulation cooling system directly exchanges heat with the high-conductivity hot water cooling plate via an ethylene glycol-water mixture. After heat exchange, the high-temperature liquid exits the high-conductivity hot water cooling plate and separates into multiple capillary tubes. These capillary tubes are installed within multiple external circulation low-temperature liquid passages. The heat from the internal circulation high-temperature liquid is exchanged within the external circulation low-temperature liquid passages using an external circulation ethylene glycol-water mixture. The external circulation liquid passages are horizontally designed, and the heat is carried away by the air-cooling system. After heat exchange in the external circulation low-temperature liquid passages, the high-temperature liquid exits the external circulation cooling medium and separates into multiple capillary tubes. These capillary tubes are horizontally designed and mounted on the top of the equipment. The system also includes... The external high-temperature coil cooling fan carries away the heat from the external circulating medium through the air, thus completing the system's cooling. The horizontal, separate air-water cooling design benefits the equipment in the following ways: The dual-circulation, separate water cooling system significantly increases system flexibility. On one hand, the heat exchange chambers of the internal and external systems can be located near the inlet pipes of the high-conductivity hot water cooling plates of the rectifier and inverter. This effectively shortens the coolant path length, improves cooling efficiency, and efficiently solves the structural limitations on the cooling system. It also greatly eliminates the influence of bends on the flow resistance of the coolant path, making the system's coolant path smoother and further improving cooling efficiency. On the other hand, the separate design of the cooling system allows for smaller unit volumes, making it possible to horizontally mount the external circulating cooler on top of the system. This design method, while ensuring cooling performance, greatly reduces the size and weight of the system, making it particularly suitable for small-sized, lightweight, high-power vehicle-mounted equipment.

[0011] Preferably, the system includes triple shock absorption and is a high-pressure, high-displacement, vehicle-mounted skid-mounted device. The vibration sources primarily originate from two sources: firstly, irregular multi-directional resonances generated during vehicle transportation; and secondly, the regular resonances generated at different frequencies by the high-power plunger pump during operation after the equipment is in place. The first layer of shock absorption consists of dampers installed on the gooseneck platform of the trailer and the back of the cabin mounting plate. The dampers on the gooseneck platform primarily buffer the vertical vibrations of the entire cabin during transportation, while the dampers on the back of the cabin mounting plate buffer the left-right vibrations of the high-power plunger pump after the equipment is in place. The first layer of vibration is to the right. The second layer of vibration protection is the flexible connection of the cooling system liquid pipeline. This is mainly for the cooling system liquid pipeline. During the equipment design, flexible connection hoses are used to connect the rectifier and inverter water cooling plates to the liquid outlet pipe, the liquid outlet pipe to the internal circulation cooling capillary tube, and the external circulation low temperature heat exchange chamber to the external circulation inlet and outlet pipes, etc., to enhance the vibration resistance of the liquid circuit system. The third layer of vibration protection is the soldering reinforcement of the main current power circuit. The adoption of multiple vibration protection technologies and measures effectively ensures that the maximum vibration value of the equipment as a whole is always kept within 4.5g, which improves the stability and reliability of the equipment.

[0012] Preferably, a staggered low-harmonic design method is adopted. Since the equipment is 4500KW and 3.3KV, it adopts three-level NPC technology and 12-pulse rectification. The harmonics of a single unit fully meet the national standards. However, fracturing operations generally require at least 14 units of equipment to be put into operation at the same time, which directly leads to harmonic resonance of multiple units with the same phase and frequency. Therefore, when designing the overall system, the equipment is divided into three equally distributed designs. The phase shifting transformers have electrical angles of 0º / 60º, +20º / -40º, and -20º / +40º, respectively, with a total of thirty-six pulse rectifications. This greatly reduces the possibility of system harmonic resonance and ensures the safety of the overall system equipment.

[0013] Preferably, the system adopts a fully automatic soft-key design, with all operations performed on the software screen. Except for emergency stop, the system has no physical buttons. System standby, start-up, and shutdown are entirely executed by software. The system features one-click standby and a self-healing system. Once the high-voltage power supply is available, the equipment can perform one-click standby via the software. During standby, the system self-checks for condensation and insulation, and activates the self-healing system. Once conditions are met, it automatically performs pre-charging and power-on, completing the system standby. The system addresses two key issues: First, equipment safety. Since the equipment operates outdoors for extended periods, its temperature characteristics vary across seasons and regions. With a high-voltage power supply available, the system allows for one-click backup via software, completely eliminating equipment malfunctions caused by human error or misjudgment, thus ensuring equipment safety. Second, personnel safety. The equipment is skid-mounted with a large-displacement high-pressure plunger pump. During fracturing operations, the high-temperature, high-pressure liquid process pipelines, containing chemical acids, pose a significant threat to the lives of operators and maintenance personnel. The development of the fully automated soft-key system enables remote operation, ensuring personnel safety.

[0014] A control method for a high-power electric drive system for vehicles, when put into operation, includes the following steps: S1) Safe power-on: Before the power grid supplies power, manually close the load switch and circuit breaker, close the front-end power system switch to send the 10KV high-voltage power supply to the power input unit, and manually close the high-voltage load switch. S2) Parameter verification: Verify all system parameters; S3) System power-on: After checking the system environment and operating conditions and ensuring that the safety requirements are fully met, the main power system is powered on. First, a command is sent to the pre-charging unit, which includes a pre-charging group and a high-voltage vacuum contactor. The high-voltage vacuum contactor closes first, and the electrical energy is used to pre-magnetize the phase-shifting transformer after being limited by the load switch, the high-voltage pre-charging resistor and the high-voltage vacuum contactor. After the pre-magnetization is completed, a circuit breaker closing command is sent. After the circuit breaker closes, the high-voltage vacuum contactor is automatically disconnected. S4) Cooling system operation: When the phase-shifting transformer and medium-voltage frequency converter are put into operation, the cooling system is started to provide cooling for the phase-shifting transformer and medium-voltage frequency converter; S5) Start-up and shutdown: The medium-voltage frequency converter performs a self-test. After the self-test is normal, the system issues a ready signal. At this time, the conditions for starting are fully met, and the medium-voltage motor of the fracturing pump can be started and stopped remotely or locally as needed.

[0015] Preferably, after the operation is completed, the phase-shifting transformer is disconnected from the main power system; when construction work is required, the relevant actions are continued from step S3; when an emergency shutdown is required, the circuit breaker is directly disconnected, and the phase-shifting transformer is triggered to cut off power.

[0016] In this invention, a stepped two-stage energy control design is adopted. After the system receives a 10KV power input, it is continuously separated into two stages through a load switch and a circuit breaker. The control-type low voltage is obtained from the first-stage load switch through a fuse, while the driving power-type high voltage is obtained from the second-stage high-voltage circuit breaker. This achieves the following three advantages: First, it ensures safe and reliable energy isolation during system operation and maintenance, significantly improving security; Secondly, the monitoring and self-healing system during the equipment standby phase is directly derived from a safe and reliable low-voltage, low-energy system. This means that the equipment has judgment and self-healing capabilities during the standby phase. During the energy path establishment phase, the system uses the low-voltage system to perform low-voltage energy limiting and slow charging on the DC bus. Only after the system bus is charged to a safe range can the high-voltage, high-energy high-voltage circuit be connected. This low-energy, low-risk control of high-energy, high-risk not only effectively reduces system impact but also greatly expands the equipment's adaptability in complex construction environments, improves equipment reliability, and reduces equipment failure rate. Third, in terms of system energy saving, under the traditional model, the large-capacity main transformer needs to be online during the standby phase of construction, resulting in no-load loss of nearly 100 kilowatts per transformer. The development of the stepped two-level energy control design method allows the use of low-energy transformer power during the standby phase, directly avoiding power waste during the downtime of the large-capacity transformer. The offline operation of the main transformer is also of great benefit to the safety of the site.

[0017] Compared with the prior art, the present invention has the following advantages: 1. By designing the electric drive system and pump skid system in a lightweight, compact, energy-saving, and intelligent manner and integrating them into a single skid on a trailer, the high-power, high-displacement fracturing pump skid and its drive system in the field of fracturing engineering have been integrated into a single skid on a vehicle. This has changed the electric drive construction operation mode in the field of fracturing engineering. Many unfavorable factors such as multiple skids and multiple transfers and hoisting, long-distance high-voltage cable laying and cable tray laying at the well site, and the coexistence of multiple risk areas such as high liquid pressure and high electrical pressure have been completely eliminated. Under the condition of meeting the relevant process power, the intensity of on-site operations has been greatly reduced, the operating cost has been reduced, and the on-site risks have been reduced. 2. By designing a stepped two-stage energy control system, low-energy and low-risk control of high-energy and high-risk systems is achieved. This not only effectively reduces system impact but also greatly expands the equipment's adaptability in complex construction environments, improves equipment reliability, and reduces equipment failure rate. At the same time, low-energy transformer power can be used during standby, directly avoiding power waste during the downtime of large-capacity transformers and achieving energy saving and consumption reduction. 3. By designing a multi-stage progressive air duct, a balance between multi-layer protection and high air intake is achieved. While meeting the overall high protection requirements, the system maintains air intake, reduces the intake of foreign objects, and reduces maintenance workload. 4. By designing a horizontally separated air-water cooling system and adopting an internal and external dual circulation structure, the size and weight of the system are greatly reduced while ensuring the cooling effect, making it particularly suitable for small-sized, lightweight, and high-power equipment in vehicles. 5. Through the design of multiple anti-vibration measures, triple anti-vibration measures are provided to address transportation vibration and construction resonance, ensuring that the maximum vibration value of the equipment as a whole is always kept within 4.5g, thereby improving the stability and reliability of the equipment. 6. By designing a staggered low harmonic design method, the system is divided into three groups of phase-shifting transformers with different electrical angles to achieve thirty-six-pulse rectification, which greatly reduces the possibility of system harmonic resonance and ensures the safety of the overall system equipment. 7. By designing a fully automatic soft key system, one-click backup and self-healing functions have been realized, which has basically eliminated equipment failures caused by human operation or judgment errors, ensuring equipment safety and personnel safety, and enabling remote operation. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] A vehicle-mounted high-power electric drive system includes a power input unit, a high-voltage power distribution unit, a pre-charge unit, a phase-shifting transformer, a medium-voltage frequency converter, a cooling system, and a control unit. The power input unit is electrically connected to the output terminal of the well site power supply equipment switch. The high-voltage power distribution unit is connected to the power input unit and consists of a load switch and a circuit breaker connected in series. The load switch is connected to a fuse to output low-voltage control power. The circuit breaker is connected in sequence to the phase-shifting transformer and the medium-voltage frequency converter to provide the main power supply for the medium-voltage motor of the fracturing pump. The input terminal of the pre-charge unit is connected to the load switch, and the output terminal is connected to the phase-shifting transformer. The cooling system provides cooling for the phase-shifting transformer and the medium-voltage frequency converter. The control unit is electrically connected to the high-voltage power distribution unit, the medium-voltage frequency converter, and the cooling system, respectively.

[0020] In this embodiment, the power input unit adopts a 10KV input, the system capacity is configured to be no less than 5800KVA, the single-unit drive power is no less than 4500kW / 3.3KV, the system size is no greater than 4750mm×2500mm×2300mm, the overall weight is no greater than 13.5T, the whole machine is installed on the gooseneck platform of the trailer, and the overall height after installation is no greater than 4 meters. The fracturing pump skid is installed on the rear trailer platform. The 10KV high voltage is connected to the system through the side, and after passing through the switch cabinet, phase shift transformer and medium voltage frequency converter, it is directly connected to the medium voltage motor of the fracturing pump installed on the trailer by cable. The pump skid and the electric drive system are integrated into the trailer.

[0021] In this embodiment, a multi-level progressive air duct design is adopted, including four layers of protection: the first layer of protection is the louver on the outer wall of the cabin; the second layer of protection is a double-detour structure; the third layer of protection is a 5um-level filter; the fourth layer of protection is a 1um-level filter; and there are preset air duct buffer intervals between different protection levels.

[0022] In this embodiment, the cooling system includes an air-cooled system and a water-cooled system. The air-cooled system provides cooling for the phase-shifting transformer, and the water-cooled system provides cooling for the medium-voltage frequency converter. The medium-voltage frequency converter adopts an NPC three-level structure with separate designs for the rectifier and inverter units. The rectifier and inverter units are mounted on a high-conductivity hot water cooling plate. The water-cooled system adopts an internal and external dual-circulation structure with completely separate internal and external circulation channels. The internal circulation cooling system directly exchanges heat with the high-conductivity hot water cooling plate through a glycol-water mixed medium, while the external circulation channel adopts a horizontal design and removes heat through the air-cooled system.

[0023] In this embodiment, triple shock protection is included: the first layer of shock protection is a shock-absorbing damper installed on the back of the trailer gooseneck platform and the cabin mounting plate; the second layer of shock protection is a flexible connecting hose connection for the cooling system liquid pipeline; and the third layer of shock protection is the soldering reinforcement of the main current power circuit.

[0024] In this embodiment, a staggered low harmonic design method is adopted, which is divided into three equally distributed designs, with phase-shifting transformer electrical angles of 0º / 60º, +20º / -40º, and -20º / +40º, respectively.

[0025] In this embodiment, a fully automatic soft key design is adopted, and all operations are performed on the software screen. Except for emergency stop, the system does not have physical buttons. The system's standby, start-up, and stop are all executed by the software. The system has one-click standby and self-healing system functions. After the high-voltage power supply of the equipment is available, the equipment can standby with one click through the software. During the standby process, the system self-checks condensation and insulation and starts the self-healing system. When the conditions are met, it automatically performs pre-charging and power-on to complete the system standby.

[0026] In the control method of this embodiment, the steps to be put into operation include: S1) Safe power-on: Before the power grid supplies power, manually close the load switch and circuit breaker, close the front-end power system switch to send the 10KV high-voltage power supply to the power input unit, and manually close the high-voltage load switch. S2) Parameter Verification: Verify all system parameters. In this embodiment, this includes the temperature and humidity sensor parameters in the main power transformer room and high-voltage distribution cabinet, setting load motor parameters, verifying the alarm temperature, shutdown temperature, insulation alarm value, motor protection value of the frequency converter rectifier and inverter unit, verifying the setting parameters of the high-voltage power distribution input cabinet integrated protection relay, verifying the circulating temperature of the liquid cooling pipe of the ethylene glycol water-cooled unit system, selecting the initial main and standby pumps, and verifying the start-up and shutdown temperature, alarm temperature, shutdown temperature, etc. of the main power transformer cooling fan. Ensure that the designed overvoltage, overcurrent, short circuit, over-temperature, fire detection, and other parameters match the system operating conditions, and that the self-healing system such as the dehumidification heating detection fan is effective. S3) System Power-On: After checking the system environment and ensuring that the safety requirements are fully met, the main power system is powered on. In this embodiment, the circuit breaker is ensured to be in automatic control mode. The equipment online function is used directly on the local touch screen. The system starts standby. During the standby process, the system self-healing system detects the system temperature, humidity, insulation, and fire detection status. Based on the insulation and temperature and humidity status, the corresponding heaters and fans of the system are started and stopped. In the power-on procedure of the main power system, the pre-charging unit is first given a command. The pre-charging unit includes a pre-charging group and a high-voltage vacuum contactor. The high-voltage vacuum contactor closes first. After the electrical energy is limited by the load switch, the high-voltage pre-charging resistor and the high-voltage vacuum contactor, it is used to pre-magnetize the phase-shifting transformer. After the pre-magnetization is completed, the circuit breaker closing command is given. After the circuit breaker closes, the high-voltage vacuum contactor is automatically disconnected. At this time, the main power supply of the system is fully connected. S4) Cooling system operation: When the phase-shifting transformer and medium-voltage frequency converter are put into operation, the cooling system is started to provide cooling for the phase-shifting transformer and medium-voltage frequency converter. Specifically, the air-cooling system of the main phase-shifting transformer starts the fan system according to the transformer winding temperature detection, and the water-cooling system of the frequency converter rectifier and inverter starts the internal circulation and external circulation systems according to the liquid situation in the corresponding water-cooled plate temperature cavity. S5) Start-up and shutdown: The medium-voltage frequency converter performs a self-test. After the self-test is normal, the system issues a ready signal. At this time, the conditions for starting are fully met, and the medium-voltage motor of the fracturing pump can be started and stopped remotely or locally as needed.

[0027] After the work is completed, disconnect the phase-shifting transformer from the main power system; when construction work is required, continue to perform the relevant actions from step S3; when an emergency shutdown is required, directly disconnect the circuit breaker, and the phase-shifting transformer will be triggered to cut off power.

[0028] This invention relates to a vehicle-mounted high-power electric drive system and its control method. By integrating the electric drive system and pump skid system into a single skid on a trailer in a lightweight, compact, energy-efficient, and intelligent design, it achieves vehicle-mounted integration of high-power, high-displacement fracturing pump skids and their drive systems in the fracturing engineering field. This completely revolutionizes the electric drive construction operation mode in fracturing engineering. It completely eliminates many unfavorable factors such as multiple skids and multiple transfers and hoisting, long-distance high-voltage cable laying and cable tray installation at the well site, and the coexistence of multiple risk areas such as high liquid pressure and high electrical pressure. Under the condition of meeting the relevant process power, it significantly reduces the intensity of on-site operations, lowers operating costs, and reduces on-site risks. Through the design of a stepped two-level energy control design, a multi-level progressive air duct design, a horizontal separate air-water cooling design, multiple anti-vibration designs, a staggered low harmonic design method, and a fully automatic "soft key" system, it achieves high reliability, high safety, high efficiency, and intelligence of the system, providing a revolutionary technical solution for fracturing engineering construction.

[0029] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this invention is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solutions of this invention are defined only by the scope of the claims.

[0030] The shapes, dimensions, ratios, angles, and figures disclosed in the description of various aspects of this specification and claims are merely examples, and therefore, this specification and claims are not limited to the details shown. In the following description, detailed descriptions of relevant known functions or configurations will be omitted where it would be determined that they unnecessarily obscure the focus of this specification and claims.

[0031] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention should be considered within the protection scope of the present invention.

Claims

1. A vehicle-mounted high-power electric drive system, characterized in that: The system includes a power input unit, a high-voltage power distribution unit, a pre-charge unit, a phase-shifting transformer, a medium-voltage frequency converter, a cooling system, and a control unit. The power input unit is electrically connected to the output terminal of the well site power supply equipment switch. The high-voltage power distribution unit is connected to the power input unit and consists of a load switch and a circuit breaker connected in series. The load switch is connected to a fuse to output low-voltage control power. The circuit breaker is connected in sequence to the phase-shifting transformer and the medium-voltage frequency converter to provide the main power supply for the medium-voltage motor of the fracturing pump. The input terminal of the pre-charge unit is connected to the load switch, and the output terminal is connected to the phase-shifting transformer. The cooling system provides cooling for the phase-shifting transformer and the medium-voltage frequency converter. The control unit is electrically connected to the high-voltage power distribution unit, the medium-voltage frequency converter, and the cooling system.

2. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: The power input unit adopts 10KV input, the system capacity is configured to be no less than 5800KVA, the single unit drive power is no less than 4500kW / 3.3KV, the system size is no greater than 4750mm×2500mm×2300mm, the overall weight is no greater than 13.5T, the whole unit is installed on the gooseneck platform of the trailer, and the overall height after installation is no greater than 4 meters. The fracturing pump skid is installed on the rear trailer platform. The 10KV high voltage is connected to the system through the side, and after passing through the switch cabinet, phase shift transformer and medium voltage frequency converter, it is directly connected to the medium voltage motor of the fracturing pump installed on the trailer by cable. The pump skid and electric drive system are integrated into the trailer.

3. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: It adopts a multi-level progressive air duct design, including four layers of protection: the first layer of protection is the louver on the outer wall of the cabin; the second layer of protection is a double-roundabout structure; the third layer of protection is a 5um-level filter; the fourth layer of protection is a 1um-level filter; and there are preset air duct buffer intervals between different protection levels.

4. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: The cooling system includes an air-cooled system and a water-cooled system. The air-cooled system provides cooling for the phase-shifting transformer, and the water-cooled system provides cooling for the medium-voltage frequency converter.

5. The vehicle-mounted high-power electric drive system as described in claim 4, characterized in that: The medium-voltage frequency converter adopts an NPC three-level structure with separate design of the rectifier unit and inverter unit. The rectifier unit and inverter unit are mounted on a high-conductivity hot water cooling plate. The water cooling system adopts an internal and external dual circulation structure with completely separate internal and external circulation liquid paths. The internal circulation cooling system directly exchanges heat with the high-conductivity hot water cooling plate through a glycol-water mixed medium. The external circulation liquid path adopts a horizontal design and removes heat through the air cooling system.

6. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: It includes triple shock protection: the first layer of shock protection is the shock damper installed on the back of the trailer gooseneck platform and the hull mounting plate; the second layer of shock protection is the flexible connection hose of the cooling system liquid pipeline; and the third layer of shock protection is the soldering reinforcement of the main current power circuit.

7. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: The staggered low harmonic design method is adopted, which is divided into three equally distributed designs, with phase-shifting transformer electrical angles of 0º / 60º, +20º / -40º, and -20º / +40º respectively.

8. The vehicle-mounted high-power electric drive system as described in claim 1, characterized in that: The system adopts a fully automatic soft key design, and all operations are performed on the software screen. Except for emergency stop, the system does not have physical buttons. The system's standby, start-up, and stop are all executed by the software. The system has one-click standby and self-healing system functions. After the high-voltage power supply of the equipment is available, the equipment can be switched to standby mode with one click through the software. During the standby process, the system self-checks condensation and insulation and starts the self-healing system. Once the conditions are met, it automatically performs pre-charging and power-on to complete the system standby.

9. A control method for a vehicle-mounted high-power electric drive system as described in any one of claims 1 to 8, characterized in that: The process of putting the device into operation includes the following steps: S1) Safe power-on: Before the power grid supplies power, manually close the load switch and circuit breaker, close the front-end power system switch to send the 10KV high-voltage power supply to the power input unit, and manually close the high-voltage load switch. S2) Parameter verification: Verify all system parameters; S3) System power-on: After checking the system environment and operating conditions and ensuring that the safety requirements are fully met, the main power system is powered on. First, a command is sent to the pre-charging unit, which includes a pre-charging group and a high-voltage vacuum contactor. The high-voltage vacuum contactor closes first, and the electrical energy is used to pre-magnetize the phase-shifting transformer after being limited by the load switch, the high-voltage pre-charging resistor and the high-voltage vacuum contactor. After the pre-magnetization is completed, a circuit breaker closing command is sent. After the circuit breaker closes, the high-voltage vacuum contactor is automatically disconnected. S4) Cooling system operation: When the phase-shifting transformer and medium-voltage frequency converter are put into operation, the cooling system is started to provide cooling for the phase-shifting transformer and medium-voltage frequency converter; S5) Start-up and shutdown: The medium-voltage frequency converter performs a self-test. After the self-test is normal, the system issues a ready signal. At this time, the conditions for starting are fully met, and the medium-voltage motor of the fracturing pump can be started and stopped remotely or locally as needed.

10. The control method for the vehicle-mounted high-power electric drive system as described in claim 9, characterized in that: After the operation is completed, the phase-shifting transformer is disconnected from the main power system; when construction work is required, the relevant actions are performed from step S3; when an emergency shutdown is required, the circuit breaker is directly disconnected, and the phase-shifting transformer is triggered to cut off power.