Variable speed regulating electric centrifugal pump with flow feedback and its flow control method

Abstract

This invention discloses a variable-speed adjustable electric centrifugal pump with flow feedback and its flow control method, belonging to the field of aero-engine control technology. The electric centrifugal pump includes a permanent magnet synchronous motor, a centrifugal pump, a differential pressure regulating valve, a metering valve, a linear variable differential transformer (LVDT), and a motor controller. The motor controller receives fuel mass flow commands from the engine controller and metering valve opening signals from the LVDT, and outputs motor control commands to adjust the centrifugal pump speed to change its outlet pressure. The differential pressure regulating valve senses this pressure change and drives the metering valve core to move, changing the opening of the metering orifice, thereby regulating the fuel flow. The LVDT detects the opening in real time and provides feedback, forming a closed-loop flow control. This invention achieves on-demand supply of pump outlet pressure through variable-speed regulation and achieves precise flow measurement and feedback through the synergistic effect of the differential pressure regulating valve and the metering valve, eliminating the pressure loss caused by traditional throttling valves and significantly improving system efficiency.

Description

Technical Field

[0001] This invention relates to the field of aero-engine control technology, and in particular to a variable speed regulating electric centrifugal pump with flow feedback for aero-engine fuel systems and a flow control method thereof. Background Technology

[0002] Multi-electric / all-electric aero-engines represent the development trend of next-generation advanced engines. As a key component for achieving multi-electric / all-electric control, intelligent control, and distributed control, the performance of the electric fuel pump is crucial. Currently, the electric motor-driven gear pump solution is limited by the gear pump's maximum speed (typically not exceeding 15,000 r / min), which restricts the improvement of the electric fuel pump's motor power density. In contrast, the high-pressure centrifugal pumps used in aero-engine fuel systems can reach rated speeds of 27,000 r / min or even 45,000 r / min, providing superior conditions for improving the electric fuel pump's motor power density. Furthermore, centrifugal pumps typically achieve efficiencies exceeding 60% at their rated point, comparable to gear pumps, ensuring that under the same fuel supply conditions, the motor power of electric centrifugal pumps is comparable to that of electric gear pumps. Finally, the maximum flow rate of centrifugal pumps is significantly greater than that of gear pumps, making electric centrifugal pumps applicable to a wider range of scenarios.

[0003] However, applying electric centrifugal pumps to the precise metering and feedback of fuel flow faces several key technical challenges: First, centrifugal pumps are non-volumetric pumps, meaning their outlet pressure is directly proportional to their speed. The outlet flow rate is determined by both the pump's flow-pressure characteristics and the load's flow-pressure characteristics, making it impossible to directly adjust the pump's outlet flow rate through speed control. Currently, when aero-engine fuel systems use centrifugal pumps to supply fuel to the engine, the pump is driven by the engine accessory casing, and the pump speed is coupled to the engine speed, preventing free adjustment. Fuel metering devices after the centrifugal pump typically use throttle valves to dissipate excess pressure at the pump outlet, increasing pressure loss, reducing fuel system efficiency, and increasing the burden on engine thermal management. Third, the fuel metering module used with the electric centrifugal pump needs to have both fuel flow metering capabilities and the ability to adjust and provide feedback on the metered flow rate in response to changes in the centrifugal pump's speed (i.e., changes in outlet pressure). Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a variable speed regulating electric centrifugal pump with flow feedback and its flow control method to solve the above-mentioned technical problems.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a variable speed regulating electric centrifugal pump with flow feedback, comprising a permanent magnet synchronous motor, a centrifugal pump, a differential pressure regulating valve, a metering valve, a linear variable differential transformer (LVDT), and a motor controller. The centrifugal pump is driven by the permanent magnet synchronous motor, achieving decoupling from the engine speed. The motor controller receives fuel mass flow commands from the engine controller and metering valve opening signals from the LVDT, and outputs a speed control signal through a closed-loop control algorithm to drive the permanent magnet synchronous motor. The valve core of the differential pressure regulating valve is a spool valve structure, with its two ends sensing the pre-metering oil pressure at the centrifugal pump outlet and the post-metering oil pressure at the metering valve outlet, respectively. The valve core of the metering valve is connected to the LVDT; the up-and-down movement of the valve core changes the opening of the metering orifice of the metering valve. The differential pressure regulating valve connects to the upper and lower chambers of the metering valve core via an oil circuit and controls the oil pressure in the upper and lower chambers of the metering valve core, thereby converting changes in the centrifugal pump outlet pressure into changes in the opening of the metering orifice of the metering valve.

[0007] Secondly, the present invention provides a flow control method based on the above-mentioned electric centrifugal pump, comprising: a motor controller receiving a fuel mass flow command from an engine controller and acquiring a current opening signal of the metering valve fed back by an LVDT; the motor controller generating a speed control signal for a permanent magnet synchronous motor based on the mass flow command and the current opening signal through a closed-loop control algorithm to drive the centrifugal pump to reach a target speed; sensing changes in the outlet pressure of the centrifugal pump through an equal differential pressure regulating valve and driving the valve core of the metering valve to move, thereby adjusting the opening of the metering orifice of the metering valve to a position corresponding to the target flow; and detecting changes in the opening in real time through an LVDT and feeding them back to the motor controller to close the flow control loop.

[0008] The beneficial effects of this invention include:

[0009] First, this invention directly drives the centrifugal pump using a permanent magnet synchronous motor, achieving complete decoupling between the centrifugal pump speed and the engine speed. This allows the centrifugal pump speed to be freely and quickly adjusted according to demand. Simultaneously, by varying the speed to achieve on-demand pressure supply, it eliminates the traditional throttling and pressure reduction method, significantly reducing system pressure loss and power consumption, and improving the overall efficiency of the fuel system.

[0010] Secondly, this invention employs a mechanical-hydraulic feedback system comprised of a differential pressure regulating valve, a metering valve, and an LVDT (Low Volume Dynamics Throttle). This system transforms the difficult-to-measure outlet flow rate of a non-volumetric centrifugal pump into a precisely measurable valve opening signal for feedback, achieving high-precision closed-loop flow control and solving the flow metering problem of electric centrifugal pumps. Furthermore, the system composed of the differential pressure regulating valve and the metering valve is highly responsive to pressure changes, quickly driving the metering valve core to a new equilibrium position. Simultaneously, the system's internal pressure feedback self-balancing mechanism ultimately returns the differential pressure regulating valve core to its equilibrium position, ensuring stability at different flow rates.

[0011] Finally, this invention establishes a one-to-one mapping relationship between the electric centrifugal pump speed, outlet pressure, metering valve opening, and outlet flow rate, thereby achieving accurate metering of the electric centrifugal pump's outlet flow rate. It employs a technical solution involving a permanent magnet synchronous motor, motor controller, centrifugal pump, differential pressure regulating valve, metering valve, and linear variable differential transformer (LVDT) to achieve closed-loop control of the electric centrifugal pump's outlet flow rate and precise on-demand pressure supply. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram illustrating the principle of a variable speed adjustable electric centrifugal pump with flow feedback under stable operating conditions according to an embodiment of the present invention.

[0014] Figure 2 This is a schematic diagram illustrating the unstable operating state of a variable speed regulating electric centrifugal pump with flow feedback when the flow rate increases, according to an embodiment of the present invention.

[0015] Figure 3 This is a schematic diagram illustrating the unstable operating state of a variable speed regulating electric centrifugal pump with flow feedback when the flow rate decreases, according to an embodiment of the present invention.

[0016] Figure 4 This is a comparative diagram of the structural principles of an oil supply and metering device for a variable speed electric centrifugal pump (a) with flow feedback and a traditional centrifugal pump (b) according to an embodiment of the present invention.

[0017] Figure 5 This is a comparison chart of the working PQ curves of a variable speed electric centrifugal pump with flow feedback and a traditional centrifugal pump oil supply and metering device according to an embodiment of the present invention. Detailed Implementation

[0018] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0019] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0021] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] This invention provides a variable speed regulating electric centrifugal pump with flow feedback and its control method, as described below. Figures 1 to 5 Provide a detailed description.

[0023] In one embodiment, refer to Figure 1 This paper proposes a variable speed regulating electric centrifugal pump with flow feedback. The electric centrifugal pump mainly includes a permanent magnet synchronous motor 1, a centrifugal pump 2, an equal pressure differential regulating valve 6, a metering valve 11, a linear variable differential transformer (LVDT) 10, and a motor controller 15. The permanent magnet synchronous motor 1 directly drives the centrifugal pump 2. This structure can decouple the centrifugal pump speed from the engine speed, thus providing a basis for variable speed regulation.

[0024] The valve core of the differential pressure regulating valve 6, namely the valve core 6-5, is a slide valve with three convex edges: upper, middle, and lower. The two ends of the valve core 6-5 sense the pre-metering oil pressure at the outlet of the centrifugal pump 2 and the post-metering oil pressure at the outlet of the metering valve 11, respectively. The upper convex edge of the valve core 6-5 of the differential pressure regulating valve is configured to control the connection or disconnection between the upper annular groove 6-2 and the upper cavity 6-1 of the valve core, and to control the connection or disconnection between the upper annular groove 6-2 and the secondary upper annular groove 6-3 of the differential pressure regulating valve; the middle convex edge of the valve core is configured to control the connection or disconnection between the secondary lower annular groove 6-4 and the secondary upper annular groove 6-3 of the differential pressure regulating valve, and to control the connection or disconnection between the secondary lower annular groove 6-4 and the lower annular groove 6-6 of the differential pressure regulating valve; the lower convex edge of the differential pressure regulating valve mainly serves as a guide for the valve core and disconnects the secondary lower annular groove 6-4 from the lower spring cavity 6-8 of the valve core.

[0025] The valve core of metering valve 11 is connected to the mover of linear variable differential transformer (LVDT) 10. The opening of metering valve metering orifice 11-5 on metering valve bushing is adjusted by moving the valve core 11-3 up and down. The metering valve metering orifice 11-5 can be rectangular, circular or other geometric shapes, and there can be several of them.

[0026] Centrifugal pump 2 outlet is split via high-pressure oil circuit 3. One path goes through fourth oil circuit 4 to the lower annular groove 6-6 of the differential pressure regulating valve, and the other path goes through fifth oil circuit 5 to the upper cavity 6-1 of the differential pressure regulating valve core and the lower annular groove 11-6 of the metering valve. Fuel is supplied to the combustion chamber through metering orifice 11-5, middle annular groove 11-4, and outlet oil circuit 12 of the metering valve. At the same time, outlet oil circuit 12 of the metering valve enters the lower spring cavity 6-8 of the differential pressure regulating valve core via sixth oil circuit 13.

[0027] The upper annular groove 6-2 of the differential pressure regulating valve is connected to the upper annular groove 11-2 of the metering valve and the upper chamber 11-1 of the metering valve core via the first oil passage 8. The lower annular groove 6-4 of the differential pressure regulating valve is connected to the lower chamber 11-7 of the metering valve core via the third oil passage 9. The upper annular groove 6-3 of the differential pressure regulating valve is connected to the low-pressure return oil via the second oil passage 7. Therefore, the movement of the metering valve core 11-3 is directly controlled by the oil pressure difference between the upper chamber 11-1 and the lower chamber 11-7 of the metering valve core, and the oil pressure difference is regulated by the differential pressure regulating valve 6.

[0028] A spring 6-7 is installed in the lower spring cavity 6-8 of the differential pressure regulating valve core. The preload and stiffness of the spring 6-7 are designed to ensure that the differential pressure regulating valve core 6-5 maintains dynamic balance under the combined action of the oil pressure before metering in the upper cavity 6-1 of the differential pressure regulating valve core, the oil pressure after metering in the lower spring cavity 6-8 of the differential pressure regulating valve core, and the spring force, and maintains the pressure difference between the oil before and after metering in the metering valve stable at 0.6MPa to 0.8MPa.

[0029] During operation, the permanent magnet synchronous motor 1 drives the centrifugal pump 2 to pressurize the low-pressure fuel from the engine. After passing through the high-pressure oil circuit 3, the fifth oil circuit 5, the lower annular groove 11-6 of the metering valve, the metering orifice 11-5 of the metering valve, the middle annular groove 11-4 of the metering valve, and the outlet oil circuit 12 of the metering valve, the fuel flows and pressures are precisely adjusted as needed to meet the fuel supply requirements of the aero-engine combustion chamber.

[0030] In one specific embodiment, refer to Figure 1 This diagram illustrates the stable operating state of a variable speed regulating electric centrifugal pump with flow feedback. In this state, the pump's speed and outlet pressure remain constant, as do the opening degrees of the differential pressure regulating valve core 6-5, the metering valve core 11-3, and the metering orifice 11-5. The working principle (flow control method) of the electric centrifugal pump in stable operating state is as follows: In stable operating state, the motor controller 15 receives a stable fuel mass flow command 16 from the engine controller and the opening signal of the metering orifice 11-5 of the metering valve 11 from the linear variable differential transformer (LVDT) 10. It then outputs a stable speed control signal 17 to the permanent magnet synchronous motor 1 through a closed-loop control algorithm. The permanent magnet synchronous motor 1 directly drives the centrifugal pump 2 to rotate to the target speed and pressurizes the low-pressure fuel from the engine to regulate the centrifugal pump's flow. The outlet pressure of pump 2, the fuel from the centrifugal pump 2 outlet, after passing through high-pressure oil circuit 3, is divided into two paths. One path flows through the fourth oil circuit 4 to the lower annular groove 6-6 of the differential pressure regulating valve; the other path flows through the fifth oil circuit 5 and is divided into two paths again. One path flows to the upper cavity 6-1 of the differential pressure regulating valve core, and the other path flows through the lower annular groove 11-6 of the metering valve, the metering orifice 11-5 of the metering valve, and the middle annular groove 11-4 of the metering valve to the outlet oil circuit 12 of the metering valve, where it is divided into two paths: one path supplies the engine combustion chamber, and the other path enters the lower spring cavity 6-8 of the differential pressure regulating valve core through the sixth oil circuit 13. For example, the closed-loop control algorithm is a PID control algorithm. The motor controller 15 converts the opening signal fed back from the LVDT into a feedback flow rate by looking up a table, and then performs closed-loop calculations based on the fuel mass flow rate received from the engine controller, outputting the centrifugal pump speed control signal.

[0031] The differential pressure regulating valve 6 senses changes in the centrifugal pump outlet pressure and drives the metering valve core 11-3 to move, adjusting the opening of the metering orifice 11-5 of the metering valve to a position corresponding to the target flow rate. Specifically, under this stable operating state, the speed of the electric centrifugal pump remains constant, the centrifugal pump outlet pressure remains constant, and the openings of the differential pressure regulating valve core 6-5, the metering valve core 11-3, and the metering orifice 11-5 also remain constant. Therefore, the differential pressure regulating valve core 6-5 is in a balanced position under the combined action of the pre-metering oil in the upper cavity 6-1 of the differential pressure regulating valve core, the post-metering oil in the lower spring cavity 6-8 of the differential pressure regulating valve core, and the differential pressure regulating valve spring 6-7. In this state, the upper convex edge of the valve core 6-5 of the differential pressure regulating valve isolates the upper cavity 6-1 of the valve core from the upper annular groove 6-2 of the differential pressure regulating valve, and the secondary upper annular groove 6-3 from the upper annular groove 6-2 of the differential pressure regulating valve; the middle convex edge of the valve core 6-5 of the differential pressure regulating valve isolates the secondary upper annular groove 6-3 from the secondary lower annular groove 6-4 of the differential pressure regulating valve, and the lower annular groove 6-6 from the secondary lower annular groove 6-4 of the differential pressure regulating valve; thus causing the upper cavity of the metering valve core to... Fuel in chambers 11-1 and 11-7 of the metering valve core cannot be discharged or increased, keeping the metering valve core 11-3 in a stable position. This maintains the oil pressure balance between chambers 11-1 and 11-7 of the metering valve core, thus keeping the opening of the metering orifice 11-5 of the metering valve constant. The mover of the linear variable differential transformer (LVDT) 10 is connected to the metering valve core 11-3 and feeds back the opening of the metering orifice 11-5 to the motor controller 15. In this state, the electric centrifugal pump achieves stable output with no static error. Because the differential pressure regulating valve core 6-5 is in the balanced position, the oil circuit between the upper and lower chambers of the metering valve core 11-3 is cut off, "locking" it in its current position, so that the flow rate is not affected by small fluctuations in upstream pressure. At the same time, maintaining a constant differential pressure (0.6MPa~0.8MPa) of the metering valve ensures a linear relationship between flow rate and opening, laying the foundation for accurate metering. Compared to traditional throttling schemes, this embodiment has no additional throttling loss under steady state, resulting in high system efficiency.

[0032] When the engine control system needs to change the flow rate to the combustion chamber, the engine controller sends a changed fuel mass flow command 16 to the motor controller 15. The motor controller 15 adjusts the speed of the permanent magnet synchronous motor 1 and the centrifugal pump 2 according to the change in the fuel mass flow command 16, changes the pressure at the outlet of the centrifugal pump 2, and causes the opening of the metering valve orifice 11-5 to change accordingly. This converts the change in the centrifugal pump outlet pressure into a change in the opening of the metering valve orifice 11-5, thereby changing the flow rate through the metering valve orifice 11-5. The linear variable differential transformer (LVDT) 10 detects the opening of the metering valve orifice 11-5 in real time and feeds back the opening change signal of the metering valve orifice 11-5 to the motor controller 15, forming a closed-loop control.

[0033] In another specific embodiment, refer to Figure 2 This illustrates an unstable operating state of a variable speed regulating electric centrifugal pump with flow feedback when the flow rate increases. In this state, the engine controller sends an increased fuel mass flow command 16 to the motor controller 15. The motor controller 15 increases the speed of the permanent magnet synchronous motor 1 and the centrifugal pump 2 according to the change in the fuel mass flow command 16. The pressure at the outlet of the centrifugal pump 2 also increases accordingly, causing the opening of the metering valve orifice 11-5 to increase. The linear variable differential transformer (LVDT) 10 feeds back the signal of the opening change of the metering valve orifice 11-5 to the motor controller 15.

[0034] The working principle (flow control method) of the electric centrifugal pump in the increased flow state is as follows: In the unstable working state with increased flow, the motor controller 15 receives the increased fuel mass flow command 16 from the engine controller and the opening signal of the metering valve orifice 11-5 of the metering valve 11 fed back by the linear variable differential transformer (LVDT) 10. It then outputs an increased speed control signal 17 to the permanent magnet synchronous motor 1 through a closed-loop control algorithm. The permanent magnet synchronous motor 1 directly drives the centrifugal pump 2 to accelerate and reach the target speed. The fuel at the outlet of the centrifugal pump 2 is divided into two paths after passing through the high-pressure oil circuit 3. One oil path flows through the fourth oil passage 4 to the lower annular groove 6-6 of the differential pressure regulating valve; the other path flows through the fifth oil passage 5 and then splits into two paths again. One path flows through the upper cavity 6-1 of the differential pressure regulating valve core, the upper annular groove 6-2 of the differential pressure regulating valve, the first oil passage 8, and the upper annular groove 11-2 of the metering valve to the upper cavity 11-1 of the metering valve core. The other path flows through the lower annular groove 11-6 of the metering valve, the metering orifice 11-5 of the metering valve, and the middle annular groove 11-4 of the metering valve to the outlet oil passage 12 of the metering valve and then splits into two paths. One path supplies the engine combustion chamber, and the other path enters the lower spring cavity 6-8 of the differential pressure regulating valve core through the sixth oil passage 13. The lower cavity 11-7 of the metering valve core is connected to the low-pressure return oil via the third oil passage 9, the lower annular groove 6-4 of the differential pressure regulating valve, the upper annular groove 6-3 of the differential pressure regulating valve, and the second oil passage 7.

[0035] The differential pressure regulating valve 6 senses changes in the centrifugal pump outlet pressure and drives the metering valve core 11-3 to move, adjusting the opening of the metering orifice 11-5 to correspond to the target flow rate. Specifically, as mentioned above, in the unstable operating state with increased flow, the centrifugal pump 2's speed increases, and the centrifugal pump outlet pressure also increases. This causes an increase in the pressure of the pre-metering oil in the upper chamber 6-1 of the differential pressure regulating valve core connected to the centrifugal pump outlet. At this time, the oil pressure of the post-metering oil in the lower spring chamber 6-8 of the differential pressure regulating valve core has not changed, causing the force balance of the differential pressure regulating valve core 6-5 to be broken. The increased pressure drives the differential pressure regulating valve core 6-5 to move downwards, i.e., the differential pressure regulating valve core... The upper convex edge of 6-5 moves downward, thereby causing the upper cavity 6-1 of the differential pressure regulating valve core to connect with the upper annular groove 6-2 of the differential pressure regulating valve, and causing the secondary upper annular groove 6-3 of the differential pressure regulating valve to be separated from the upper annular groove 6-2 of the differential pressure regulating valve; at the same time, the middle convex edge of the differential pressure regulating valve core 6-5 also moves downward, causing the secondary upper annular groove 6-3 of the differential pressure regulating valve to connect with the secondary lower annular groove 6-4 of the differential pressure regulating valve, and causing the lower annular groove 6-6 of the differential pressure regulating valve to be separated from the secondary lower annular groove 6-4 of the differential pressure regulating valve. This results in the upper chamber 11-1 of the metering valve core being connected to the upper chamber 6-1 of the differential pressure regulating valve core, and the lower chamber 11-7 of the metering valve core being connected to the low-pressure return oil. The upper chamber 6-1 of the differential pressure regulating valve core is connected to the high-pressure oil circuit 3 through the fifth oil circuit 5. Therefore, the oil pressure in the upper chamber 11-1 of the metering valve core is greater than the oil pressure in the lower chamber 11-7 of the metering valve core. Under the action of the pressure difference, the metering valve core 11-3 moves downward, thereby increasing the opening of the metering orifice 11-5 of the metering valve, that is, increasing the fuel flow through the metering orifice 11-5 of the metering valve. This, in turn, increases the pressure of the oil after metering by the metering valve, that is, increases the pressure in the annular groove 11-4 of the metering valve, the outlet oil circuit 12 of the metering valve, the sixth oil circuit 13, and the lower spring chamber 6-8 of the differential pressure regulating valve core.As the pressure in the lower spring chamber 6-8 of the differential pressure regulating valve continues to rise, the valve core 6-5 of the differential pressure regulating valve moves downward under the combined action of the oil before metering in the upper chamber 6-1, the oil after metering in the lower spring chamber 6-8, and the spring 6-7, gradually decelerating until it stops. At this time, the metering valve core 11-3 continues to move downward, causing the opening of the metering orifice 11-5 to continue to increase, meaning the flow rate through the metering orifice 11-5 continues to increase. Simultaneously, the pressure in the lower spring chamber 6-8 of the differential pressure regulating valve continues to rise until it reaches the equal pressure level. Under the combined action of the upper chamber 6-1 of the differential pressure regulating valve core 6-5 (measuring the oil before the differential pressure regulating valve core), the lower spring chamber 6-8 (measuring the oil after the differential pressure regulating valve core), and the spring 6-7 of the differential pressure regulating valve core 6-5, the valve core 6-5 of the differential pressure regulating valve begins to move upward and gradually returns to the equilibrium position of the differential pressure regulating valve core 6-5 when the electric centrifugal pump is in the stable working state as described above. At this time, the valve core 11-3 of the metering valve stops moving downward, that is, the opening of the metering orifice 11-5 of the metering valve stops increasing and remains in the corresponding stable position. At this time, the opening of the metering orifice 11-5 of the metering valve is adjusted to the position corresponding to the target flow rate. The Linear Variable Differential Transformer (LVDT) 10 monitors the opening of the metering valve's metering orifice 11-5 in real time and feeds back the signal of the opening change to the motor controller 15 to close the flow control loop. When the increased fuel mass flow command 16 and the flow rate represented by the opening of the metering valve's metering orifice 11-5 fed back by the LVDT 10 reach consistency, the motor controller 15 stops further increasing the centrifugal pump speed through a closed-loop control algorithm. This process exhibits excellent dynamic responsiveness and self-stability. Through mechanical-hydraulic feedback, it automatically converts the pressure change caused by the increase in speed into a precise increase in flow rate. The differential pressure regulating valve can automatically drive the metering valve to a new equilibrium point and ultimately self-reset, ensuring a smooth and rapid regulation process. Ultimately, it achieves the goal of meeting the increased flow rate demand with the lowest possible outlet pressure, resulting in significant energy savings.

[0036] In another specific embodiment, refer to Figure 3 This illustrates a variable speed regulating electric centrifugal pump with flow feedback. In an unstable operating state with reduced flow, the engine controller sends a reduced fuel mass flow command 16 to the motor controller 15. The motor controller 15 reduces the speed of the permanent magnet synchronous motor 1 and the centrifugal pump 2 according to the change in the fuel mass flow command 16. The pressure and flow at the outlet of the centrifugal pump 2 also decrease accordingly, resulting in a decrease in the opening of the metering valve orifice 11-5. The linear variable differential transformer (LVDT) 10 will detect the opening of the metering valve orifice 11-5 in real time and feed back the signal of the change in the opening of the metering valve orifice 11-5 to the motor controller 15.

[0037] The working principle (flow control method) of the electric centrifugal pump in the working state of reduced flow is as follows: In the unstable working state of reduced flow, the motor controller 15 receives the reduced fuel mass flow command 16 issued by the engine controller and the opening signal of the metering valve orifice 11-5 of the metering valve 11 fed back by the linear variable differential transformer (LVDT) 10, and outputs the reduced speed control signal 17 to the permanent magnet synchronous motor 1 through the closed-loop control algorithm. The permanent magnet synchronous motor 1 directly drives the centrifugal pump 2 to decelerate and rotate to reach the target speed, so as to reduce the outlet pressure of the centrifugal pump. The fuel from the centrifugal pump 2 outlet is split into two paths after passing through the high-pressure oil circuit 3. One path flows through the fourth oil circuit 4, the lower annular groove 6-6 of the differential pressure regulating valve, the secondary lower annular groove 6-4 of the differential pressure regulating valve, and the third oil circuit 9 to the lower chamber 11-7 of the metering valve core. The other path flows through the fifth oil circuit 5 and is split into two paths again. One path flows to the upper chamber 6-1 of the differential pressure regulating valve core, and the other path flows through the lower annular groove 11-6 of the metering valve, the metering orifice 11-5 of the metering valve, and the middle annular groove 11-4 of the metering valve to the metering valve outlet oil circuit 12, where it is split into two paths: one path supplies the engine combustion chamber, and the other path enters the lower spring chamber 6-8 of the differential pressure regulating valve core via the sixth oil circuit 13. The upper chamber 11-1 of the metering valve core is connected to the low-pressure return oil via the first oil circuit 8, the upper annular groove 6-2 of the differential pressure regulating valve, the secondary upper annular groove 6-3 of the differential pressure regulating valve, and the second oil circuit 7.

[0038] The differential pressure regulating valve 6 senses changes in the centrifugal pump outlet pressure and drives the metering valve core 11-3 to move, adjusting the opening of the metering orifice 11-5 to correspond to the target flow rate. Specifically, as described above, in the unstable operating state with reduced flow, the centrifugal pump 2's speed decreases, and the centrifugal pump outlet pressure also decreases. This leads to a decrease in the pressure of the oil before metering in the upper chamber 6-1 of the differential pressure regulating valve core connected to the centrifugal pump outlet. Meanwhile, the oil pressure after metering in the lower spring chamber 6-8 of the differential pressure regulating valve core has not changed. This disrupts the force balance of the differential pressure regulating valve core 6-5, causing it to move upwards. The upper convex edge moves upward, thereby causing the upper cavity 6-1 of the differential pressure regulating valve core to be separated from the upper annular groove 6-2 of the differential pressure regulating valve, and causing the secondary upper annular groove 6-3 of the differential pressure regulating valve to be connected to the upper annular groove 6-2 of the differential pressure regulating valve; at the same time, the middle convex edge of the differential pressure regulating valve core 6-5 also moves upward, causing the secondary upper annular groove 6-3 of the differential pressure regulating valve to be separated from the secondary lower annular groove 6-4 of the differential pressure regulating valve, and causing the lower annular groove 6-6 of the differential pressure regulating valve to be connected to the secondary lower annular groove 6-4 of the differential pressure regulating valve. This causes the upper chamber 11-1 of the metering valve core to connect with the low-pressure return oil, and the lower chamber 11-7 of the metering valve core to connect with the lower annular groove 6-6 of the differential pressure regulating valve. The lower annular groove 6-6 of the differential pressure regulating valve is connected to the high-pressure oil circuit 3 through the fourth oil circuit 4. Therefore, the oil pressure in the upper chamber 11-1 of the metering valve core is less than the oil pressure in the lower chamber 11-7 of the metering valve core. Under the action of the pressure difference, the metering valve core 11-3 moves upward, thereby reducing the opening of the metering orifice 11-5 of the metering valve, that is, reducing the fuel flow through the metering orifice 11-5 of the metering valve. Consequently, the pressure of the oil after metering by the metering valve decreases, that is, the pressure in the annular groove 11-4 of the metering valve, the outlet oil circuit 12 of the metering valve, the sixth oil circuit 13, and the lower spring chamber 6-8 of the differential pressure regulating valve core decreases.As the pressure in the lower spring chamber 6-8 of the differential pressure regulating valve core continues to decrease, the differential pressure regulating valve core 6-5, under the combined action of the pre-metering oil in the upper chamber 6-1, the post-metering oil in the lower spring chamber 6-8, and the differential pressure regulating valve spring 6-7, moves upward and gradually decelerates until it stops. At this time, the metering valve core 11-3 continues to move upward, causing the opening of the metering orifice 11-5 to continue to decrease, meaning the flow rate through the metering orifice 11-5 continues to decrease. Simultaneously, the pressure in the lower spring chamber 6-8 of the differential pressure regulating valve core continues to decrease until the differential pressure is equalized. Under the combined action of the upper chamber 6-1 of the differential pressure regulating valve core (measuring the oil before the flow) and the lower spring chamber 6-8 of the differential pressure regulating valve core (measuring the oil after the flow) and the spring 6-7 of the differential pressure regulating valve, the regulating valve core 6-5 begins to move downward and gradually returns to the equilibrium position of the differential pressure regulating valve core 6-5 when the electric centrifugal pump is in the stable working state as described above. At this time, the metering valve core 11-3 stops moving upward, that is, the opening of the metering orifice 11-5 of the metering valve stops decreasing and remains in the corresponding stable position. At this time, the opening of the metering orifice 11-5 of the metering valve is adjusted to the position corresponding to the target flow rate. The linear variable differential transformer (LVDT) 10 monitors the opening of the metering valve orifice 11-5 in real time and feeds back the opening change signal of the metering valve orifice 11-5 to the motor controller 15 to close the flow control loop. When the reduced mass flow command 16 and the flow rate represented by the opening of the metering valve orifice 11-5 fed back by the LVDT 10 reach the same level, the motor controller 15 stops further reducing the centrifugal pump speed through a closed-loop control algorithm. This process is also fast, stable, and energy-saving. It proves that the electric centrifugal pump described in this embodiment of the invention can work reliably in both directions of regulation, and the closed-loop mapping relationship of "reduced speed - reduced pressure - reduced opening - reduced flow" is stable and reliable, ensuring the accuracy of control.

[0039] In one embodiment, refer to Figure 4 (a) is a schematic diagram of a variable speed regulating electric centrifugal pump with flow feedback. The outlet pressure of the electric centrifugal pump is mainly composed of the pressure drop of the metering valve, the pressure drop of the fuel main, the nozzle pressure drop of the engine combustion chamber, and the back pressure of the combustion chamber. For example, the fuel flow rate supplied to the combustion chamber in a certain engine state is... The formula for calculating the outlet pressure of the electric centrifugal pump under this condition is as follows:

[0040]

[0041] in, For the outlet pressure of the electric centrifugal pump, For the pressure drop of the metering valve of the electric centrifugal pump, For the pressure drop in the fuel main, This refers to the pressure drop of the fuel injector. This is the back pressure in the combustion chamber.

[0042] Reference Figure 4 (b) is a schematic diagram of the traditional centrifugal pump fuel supply and metering device. The centrifugal pump outlet pressure is mainly composed of the pressure drop of the throttling constant differential pressure valve, the pressure drop of the metering valve, the pressure drop of the fuel main pipe, the nozzle pressure drop of the engine combustion chamber, and the combustion chamber back pressure. For example, the fuel flow rate supplied to the combustion chamber by the engine under the same conditions is... The formula for calculating the centrifugal pump outlet pressure under this condition is as follows:

[0043]

[0044] in, For traditional centrifugal pumps, the oil supply and metering device provides centrifugal pump outlet pressure. The pressure drop of the throttling constant differential pressure valve. The pressure drop of the metering valve in the traditional centrifugal pump's oil supply and metering device. For the pressure drop in the fuel main, This refers to the pressure drop of the fuel injector. This is the back pressure in the combustion chamber.

[0045] In this embodiment, the pressure drop of the metering valve of the electric centrifugal pump can be controlled. Pressure drop of metering valve in traditional centrifugal pump oil supply and metering device The design is the same, such as 0.6MPa to 0.8MPa; the same fuel flow rate. Under the following two fuel supply conditions, the pressure drop of the fuel main is... Fuel injector pressure drop Combustion chamber back pressure Similarly, the traditional centrifugal pump oil supply and metering device centrifugal pump outlet pressure Compared to the outlet pressure of the electric centrifugal pump described in the embodiment of the present invention To achieve a higher pressure drop than the throttling constant differential pressure valve, the engine uses the electric centrifugal pump of this embodiment to reduce pressure loss under the same operating conditions.

[0046] Furthermore, refer to Figure 5 This is a comparison of the PQ curves of a variable speed regulating electric centrifugal pump with flow feedback and a traditional centrifugal pump's oil supply and metering device, when supplying the same flow rate to the engine combustion chamber. In the case of a traditional centrifugal pump supply and metering device, the PQ curve of the centrifugal pump at speed n1 intersects with the corresponding load characteristic PQ curve at operating point A. The outlet pressure of the centrifugal pump corresponding to operating point A is... The PQ curve of a variable speed electric centrifugal pump with flow feedback in an embodiment of the present invention intersects with the corresponding load characteristic PQ curve at operating point B. The outlet pressure of the centrifugal pump at operating point B is... Where the rotational speed n1 is greater than the rotational speed n2. That is, under the same oil supply conditions, the centrifugal pump with flow feedback variable speed regulating electric centrifugal pump described in this embodiment of the invention has a lower rotational speed and a lower outlet pressure compared to the centrifugal pump with a traditional centrifugal pump oil supply and metering device, and thus lower power consumption.

[0047] Therefore, under the same fuel supply conditions, the variable speed electric centrifugal pump with flow feedback of this embodiment of the invention reduces pressure loss, improves fuel system efficiency, reduces the burden of engine fuel thermal management, and realizes on-demand supply of fuel system flow and pressure compared with traditional centrifugal pump fuel supply and metering devices.

[0048] The embodiments of the present invention address the problem that centrifugal pumps, being non-volumetric pumps, cannot directly adjust the outlet flow rate of metering centrifugal pumps through speed regulation. These embodiments employ a permanent magnet synchronous motor combined with centrifugal pump speed regulation to achieve centrifugal pump outlet pressure adjustment. Furthermore, they utilize a differential pressure regulating valve, a metering valve, and a linear variable differential transformer (LVDT) to sense changes in centrifugal pump outlet pressure and convert them into a metering valve opening corresponding to the flow rate, thus achieving precise metering and closed-loop control of the centrifugal pump outlet flow rate. Addressing the issues of traditional centrifugal pump oil supply and metering devices typically using throttle valves to dissipate excess pressure at the centrifugal pump outlet and the coupling between centrifugal pump speed and engine speed, these embodiments employ a permanent magnet synchronous motor to directly drive the centrifugal pump, enabling free rotation of the centrifugal pump speed. The invention employs a differential pressure regulating valve and a metering valve to replace the pressure drop of the throttling constant differential pressure valve, as well as the metering valve and electro-hydraulic servo valve, to achieve on-demand supply of fuel system flow and pressure, reducing pressure loss and improving fuel system efficiency. Addressing the issue of how to convert changes in centrifugal pump outlet pressure into a signal representing centrifugal pump outlet flow, this embodiment uses a differential pressure regulating valve with a slide valve to sense changes in centrifugal pump outlet pressure and adjust the metering orifice opening of the metering valve accordingly. This establishes a one-to-one mapping relationship between centrifugal pump outlet pressure, metering valve orifice opening, and centrifugal pump outlet flow, achieving precise metering of the electric centrifugal pump outlet flow. Ultimately, this enables closed-loop control of the electric centrifugal pump outlet flow and precise on-demand pressure supply.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A variable speed regulating electric centrifugal pump with flow feedback, characterized in that, include: Permanent magnet synchronous motor (1), centrifugal pump (2), equal pressure differential regulating valve (6), metering valve (11), linear variable differential transformer (10) and motor controller (15); The centrifugal pump (2) is driven by the permanent magnet synchronous motor (1); The motor controller (15) is configured to receive the fuel mass flow command (16) from the engine controller and the metering valve opening signal fed back from the linear variable differential transformer (10), and output the speed control signal (17) to the permanent magnet synchronous motor (1) through a closed-loop control algorithm. The valve core of the differential pressure regulating valve (6) is a slide valve structure. The two ends of the valve core (6-5) of the differential pressure regulating valve sense the pre-metering oil pressure at the outlet of the centrifugal pump (2) and the post-metering oil pressure at the outlet of the metering valve (11), respectively. The valve core of the metering valve (11) is connected to the linear variable differential transformer (10), and the opening degree of the metering valve orifice (11-5) is adjusted by the up and down movement of the valve core (11-3). The differential pressure regulating valve (6) is connected to the upper chamber (11-1) of the metering valve core and the lower chamber (11-7) of the metering valve core through an oil circuit, and controls the oil pressure in the upper chamber (11-1) and the lower chamber (11-7) of the metering valve core, thereby converting the change in the centrifugal pump outlet pressure into the change in the opening of the metering orifice (11-5) of the metering valve. The valve core (6-5) of the differential pressure regulating valve has three convex edges: upper, middle, and lower. The upper convex edge of the valve core of the differential pressure regulating valve is configured to control the communication or isolation between the upper annular groove (6-2) of the differential pressure regulating valve and the upper cavity (6-1) of the valve core of the differential pressure regulating valve, and to control the communication or isolation between the upper annular groove (6-2) of the differential pressure regulating valve and the secondary upper annular groove (6-3) of the differential pressure regulating valve. The convex edge of the valve core of the differential pressure regulating valve is configured to control the connection or disconnection between the secondary lower annular groove (6-4) and the secondary upper annular groove (6-3) of the differential pressure regulating valve, and to control the connection or disconnection between the secondary lower annular groove (6-4) and the lower annular groove (6-6) of the differential pressure regulating valve. The lower convex edge of the differential pressure regulating valve serves as a guide and separates the lower annular groove (6-4) of the differential pressure regulating valve from the lower spring cavity (6-8) of the valve core.

2. The electric centrifugal pump according to claim 1, characterized in that, The upper annular groove (6-2) of the differential pressure regulating valve is connected to the upper annular groove (11-2) of the metering valve and the upper cavity (11-1) of the metering valve core through the first oil passage (8); the secondary upper annular groove (6-3) of the differential pressure regulating valve is connected to the low-pressure return oil through the second oil passage (7); the secondary lower annular groove (6-4) of the differential pressure regulating valve is connected to the lower cavity (11-7) of the metering valve core through the third oil passage (9).

3. The electric centrifugal pump according to claim 1, characterized in that, The upper cavity (6-1) of the valve core of the differential pressure regulating valve and the lower annular groove (6-6) of the differential pressure regulating valve are connected to the high pressure oil circuit (3) of the centrifugal pump outlet through the fifth oil circuit (5) and the fourth oil circuit (4), respectively; the lower spring cavity (6-8) of the valve core of the differential pressure regulating valve is connected to the outlet oil circuit (12) of the metering valve through the sixth oil circuit (13).

4. The electric centrifugal pump according to claim 3, characterized in that, A spring (6-7) is provided in the lower spring cavity (6-8) of the differential pressure regulating valve core. By designing the preload and stiffness of the spring (6-7), the differential pressure regulating valve core (6-5) is kept in dynamic balance under the combined action of the oil pressure before metering in the upper cavity (6-1) of the differential pressure regulating valve core, the oil pressure after metering in the lower spring cavity (6-8) of the differential pressure regulating valve core, and the spring force, and the pressure difference between the oil before and after metering is kept stable at 0.6MPa to 0.8MPa.

5. The electric centrifugal pump according to claim 1, characterized in that, The bushing of the metering valve (11) is provided with a metering valve metering orifice (11-5), the shape of which is rectangular or circular; the opening of the metering valve metering orifice (11-5) is adjusted by moving the valve core (11-3) of the metering valve up and down.

6. The electric centrifugal pump according to claim 1, characterized in that, The movement of the metering valve core (11-3) is directly controlled by the oil pressure difference between the upper chamber (11-1) and the lower chamber (11-7) of the metering valve core, and the oil pressure difference is regulated by the differential pressure regulating valve (6).

7. A flow control method for a variable speed regulating electric centrifugal pump with flow feedback, based on the electric centrifugal pump according to any one of claims 1 to 6, characterized in that, Includes the following steps: The motor controller (15) receives the fuel mass flow command (16) from the engine controller and obtains the current opening signal of the metering valve (11) fed back by the linear variable differential transformer (10); The motor controller (15) outputs a speed control signal (17) to the permanent magnet synchronous motor (1) through a closed-loop control algorithm based on the mass flow command (16) and the current opening signal. The permanent magnet synchronous motor (1) directly drives the centrifugal pump (2) to reach the target speed according to the speed control signal (17), thereby adjusting the outlet pressure of the centrifugal pump (2). The pressure change at the outlet of the centrifugal pump (2) is sensed by the differential pressure regulating valve (6), and the valve core (11-3) of the metering valve is moved to adjust the opening of the metering orifice (11-5) of the metering valve to the position corresponding to the target flow rate. The change in the opening degree is detected in real time by a linear variable differential transformer (10) and fed back to the motor controller (15) to close the flow control loop.

8. The flow control method according to claim 7, characterized in that, When it is necessary to increase the fuel flow rate, perform the following procedure: The motor controller (15) outputs an increased speed control signal (17), which increases the speed and outlet pressure of the centrifugal pump (2); The increased pressure drives the valve core (6-5) of the differential pressure regulating valve to move downward, so that the upper chamber (11-1) of the metering valve core is connected to the high-pressure oil, and the lower chamber (11-7) of the metering valve core is connected to the low-pressure return oil. Under the action of pressure difference, the valve core (11-3) of the metering valve moves downward, which increases the opening of the metering orifice (11-5) of the metering valve, thereby increasing the fuel flow rate.

9. The flow control method according to claim 7, characterized in that, When it is necessary to reduce fuel flow, perform the following procedure: The motor controller (15) outputs a reduced speed control signal (17), which reduces the speed and outlet pressure of the centrifugal pump (2); The reduced pressure causes the valve core (6-5) of the differential pressure regulating valve to move upward, so that the upper chamber (11-1) of the metering valve core is connected to the low-pressure return oil, and the lower chamber (11-7) of the metering valve core is connected to the high-pressure oil. Under the action of pressure difference, the valve core (11-3) of the metering valve moves upward, which reduces the opening of the metering orifice (11-5) of the metering valve, thereby reducing the fuel flow rate.

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