Power System Torque Control Method and System

Abstract

A method and system for torque control of a power system. The method for torque control of the power system includes: determining the allowable torque of the power system; obtaining the actual consumed torque of non-controllable hydraulic pumps and getting the total actual consumed torque of all non-controllable hydraulic pumps; obtaining the total allowable torque that can be used by controllable hydraulic pumps according to the total actual consumed torque and the allowable torque; obtaining the control target torque of each controllable hydraulic pump according to the total allowable torque that can be used and the system predetermined distribution ratio coefficient; obtaining the target current of the controllable hydraulic pumps; and controlling the controllable hydraulic pumps according to the target current. The method and system for torque control of the power system provided by the present invention perform torque control on the controllable hydraulic pumps, thereby ensuring the total controlled torque, ensuring that the drive shafts of the controllable hydraulic pumps do not exceed the limit torque, and ensuring that the total torque of the power system does not exceed the total allowable torque that can be used, thus ensuring the reliability and safety of the power system.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method and a system for controlling the torque of a power system. Background Art

[0002] A power system includes a prime mover (engine or motor), a hydraulic pump, and an actuator. The prime mover drives the hydraulic pump, and the hydraulic pump drives the actuator to act. In applications using two or more hydraulic pumps, the total torque of the combined hydraulic pumps may exceed the torque rating of the prime mover or the input shaft of the hydraulic pump, especially in transient states. This can lead to catastrophic failures of the prime mover or the input shaft of the hydraulic pump.

[0003] Currently, it is usually necessary to select a larger model to avoid failures in the weakest link, resulting in an increase in hardware costs.

[0004] The foregoing description is provided to give general background information and does not necessarily constitute prior art.

[0005] Application Content

[0006] The object of the present invention is to provide a method and a system for controlling the torque of a power system, aiming to avoid the problem that the power system exceeds the limit torque.

[0007] The present invention provides a method for controlling the torque of a power system, which is applicable to a power system. The power system includes a prime mover, a direct-drive hydraulic pump, a first hydraulic pump, and a second hydraulic pump. One or more of the direct-drive hydraulic pumps are directly connected to the prime mover. The first hydraulic pump is connected in series after the direct-drive hydraulic pump. The second hydraulic pump is connected to the first hydraulic pump. The direct-drive hydraulic pump and the first hydraulic pump are controllable hydraulic pumps, and the second hydraulic pump is a non-controllable hydraulic pump. Each direct-drive hydraulic pump and the first hydraulic pump and / or the second hydraulic pump driven by it form a hydraulic branch. The method for controlling the torque of the power system is characterized in that it includes:

[0008] Determine the allowable torque of the power system;

[0009] Obtain the actual consumed torque of the non-controllable hydraulic pump, and obtain the total actual consumed torque of all the non-controllable hydraulic pumps;

[0010] Obtain the total allowable torque that can be used by the controllable hydraulic pumps according to the total actual consumed torque and the allowable torque: the total allowable torque that can be used is the difference between the allowable torque and the total actual consumed torque;

[0011] Obtain the control target torque of each controllable hydraulic pump according to the total allowable torque that can be used and the system predetermined distribution ratio coefficient;

[0012] Calculate the target displacement of each controllable hydraulic pump according to the control target torque and real-time outlet pressure of the controllable hydraulic pump, and then obtain the target current of the controllable hydraulic pump.

[0013] Control the controllable hydraulic pump according to the target current.

[0014] In an implementable manner, the power system is a single-path direct drive type, and the step of determining the allowable torque of the power system specifically includes:

[0015] Obtain the rotational speed of the prime mover, obtain the maximum output torque according to the rotational speed, and multiply the maximum output torque by a reasonable usage coefficient to obtain the usage torque;

[0016] Obtain the limiting torque of the direct drive hydraulic pump;

[0017] Determine the allowable torque of the power system according to the usage torque and the limiting torque, where the allowable torque is the smaller of the usage torque and the limiting torque.

[0018] In an implementable manner, obtaining the control target torque of each controllable hydraulic pump specifically includes: the control target torque of each controllable hydraulic pump is the product of the system predetermined allocation ratio coefficient of this controllable hydraulic pump and the total allowable torque, and the sum of the control target torques of each controllable hydraulic pump is less than or equal to the total allowable torque.

[0019] In an implementable manner, the power system is a multi-path direct drive type, and the step of determining the allowable torque of the power system specifically includes:

[0020] Obtain the rotational speed of the prime mover, obtain the maximum output torque according to the rotational speed, and multiply the maximum output torque by a reasonable usage coefficient to obtain the usage torque;

[0021] Obtain the total limiting torque of all the direct drive hydraulic pumps;

[0022] Determine the allowable torque of the power system according to the usage torque and the total limiting torque, where the allowable torque is the smaller of the usage torque and the total limiting torque.

[0023] In an implementable manner, obtaining the control target torques of the controllable hydraulic pumps specifically includes: the control target torque of each controllable hydraulic pump is the product of the system predetermined allocation ratio coefficient of this controllable hydraulic pump and the total torque allowed for use, and the sum of the control target torques of each controllable hydraulic pump is less than or equal to the total torque allowed for use; on each hydraulic branch, the sum of the control target torques of the direct-drive hydraulic pump and all the controllable hydraulic pumps driven by it and the sum of the actual consumption torques of all the non-controllable hydraulic pumps driven by it are less than or equal to the smaller of the use torque and the limit torque of the direct-drive hydraulic pump.

[0024] In an implementable manner, the step of obtaining the actual consumption torque of the non-controllable hydraulic pump specifically includes: calculating the output displacement of the non-controllable hydraulic pump according to the functional relationship between the outlet pressure and the output displacement of the non-controllable hydraulic pump, and then calculating the actual consumption torque of the non-controllable hydraulic pump according to the outlet pressure and the output displacement of the non-controllable hydraulic pump.

[0025] In an implementable manner, the step of controlling the controllable hydraulic pump according to the target current specifically includes: obtaining the current current of the controllable hydraulic pump, comparing the current current with the target current, and adjusting the control current of the controllable hydraulic pump according to the difference between the current current and the target current.

[0026] The present invention also provides a torque control system for a power system, applicable to a power system. The power system includes a prime mover, a direct-drive hydraulic pump, a first hydraulic pump, and a second hydraulic pump. One or more direct-drive hydraulic pumps are directly connected to the prime mover. The first hydraulic pump is connected in series behind the direct-drive hydraulic pump. The second hydraulic pump is connected to the first hydraulic pump. The direct-drive hydraulic pump and the first hydraulic pump are controllable hydraulic pumps, and the second hydraulic pump is a non-controllable hydraulic pump. Each direct-drive hydraulic pump and the first hydraulic pump and / or the second hydraulic pump driven by it form a hydraulic branch. It is characterized in that the torque control system for the power system includes:

[0027] An acquisition module, configured to acquire the rotational speed of the prime mover, the real-time outlet pressures of the first hydraulic pump and the second hydraulic pump, and configured to obtain the limit torque of the direct-drive hydraulic pump;

[0028] A data processing module is used to determine the allowable torque of the power system, obtain the actual consumed torque of the non-controllable hydraulic pump, and obtain the total actual consumed torque of all the non-controllable hydraulic pumps. The total allowable torque that the controllable hydraulic pump can use is obtained according to the total actual consumed torque and the allowable torque: the allowable used torque is the difference between the allowable torque and the total actual consumed torque. The control target torque of the controllable hydraulic pump is obtained according to the allowable used torque, and the target displacement of the controllable hydraulic pump is calculated according to the control target torque and the real-time outlet pressure of the controllable hydraulic pump, and then the target current of the controllable hydraulic pump is obtained.

[0029] A control module controls the controllable hydraulic pump according to the target current.

[0030] In an implementable manner, the power system is a single-path direct drive type. The data processing module determines the allowable torque of the power system specifically including: obtaining the maximum output torque of the prime mover according to the rotational speed of the prime mover, and multiplying the maximum output torque by a reasonable use coefficient to obtain a use torque. The allowable torque of the power system is determined according to the use torque and the limit torque, and the allowable torque is the smaller of the use torque and the limit torque.

[0031] The data processing module obtains the control target torque of each controllable hydraulic pump according to the allowable used torque specifically including: the data processing module is used to make the control target torque of each controllable hydraulic pump be the product of the system predetermined distribution ratio coefficient of this controllable hydraulic pump and the allowable used torque, and the sum of the control target torques of each controllable hydraulic pump is less than or equal to the allowable used torque.

[0032] In an implementable manner, the power system is a multi-path direct drive type. The data processing module determines the allowable torque of the power system specifically including: obtaining the maximum output torque of the prime mover according to the rotational speed of the prime mover, and obtaining a use torque according to the maximum output torque and a reasonable use coefficient. The total limit torque of all the direct drive hydraulic pumps is obtained according to the limit torque. The allowable torque of the power system is determined according to the use torque and the total limit torque: the allowable torque is the smaller of the use torque and the total limit torque; wherein, the allowable torque is the sum of the allowable torques of all the direct drive hydraulic pumps.

[0033] The data processing module obtaining the control target torque of each controllable hydraulic pump according to the total allowable torque specifically includes: the data processing module is configured to make the control target torque of each controllable hydraulic pump be the product of the system predetermined distribution ratio coefficient of this controllable hydraulic pump and the total allowable torque, and the sum of the control target torques of each controllable hydraulic pump is less than or equal to the total allowable torque, and on each hydraulic branch, the sum of the control target torques of the direct-drive hydraulic pump and all the controllable hydraulic pumps driven by it and the sum of the actual consumption torques of all the non-controllable hydraulic pumps driven by it is less than or equal to the smaller of the service torque and the limit torque of the direct-drive hydraulic pump.

[0034] Through the power system torque control method and system provided by the present invention, torque control is performed on the controllable hydraulic pump, so as to ensure the total controlled torque, ensure that the drive shaft of the controllable hydraulic pump does not exceed the limit torque, and ensure that the total torque of the power system does not exceed the total allowable torque, thereby ensuring the reliability and safety of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of a power system.

[0037] Figure 2 It is a schematic structural diagram of another power system.

[0038] Figure 3 It is a schematic flow diagram of a power system torque control method provided by the present invention.

[0039] Figure 4 In a single-channel direct-drive system Figure 3 It is a detailed flow diagram of step S11 in the flow diagram shown.

[0040] Figure 5 It is a schematic diagram of torque distribution in a single-channel direct-drive system.

[0041] Figure 6 It is a pressure-current-displacement curve diagram of an electronically controlled double-folded line constant power pump.

[0042] Figure 7It is the pressure-current displacement curve graph of the electronically controlled curve constant power pump.

[0043] Figure 8 It is the current-displacement curve graph of the electronically controlled displacement pump.

[0044] Figure 9 It is the pressure-displacement curve graph of the hydraulically controlled constant power pump.

[0045] Figure 10 For the multi-channel direct drive system Figure 3 It is the detailed process schematic diagram of step S11 in the process schematic diagram shown.

[0046] Figure 11 It is the schematic diagram of the torque distribution in the multi-channel direct drive system.

[0047] Figure 12 It is the structural schematic diagram of a torque control system for a power system provided by the present invention. Specific embodiments

[0048] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0049] It should be noted that in this article, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanations in the specific embodiments or further in combination with the context in the specific embodiments.

[0050] It should be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this document, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining". Furthermore, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the stated features, steps, operations, elements, components, items, kinds, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or", "and / or", "including at least one of the following" used in this application may be interpreted inclusively, or mean any one or any combination. For example, "including at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C", and again, "A, B or C" or "A, B and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C". An exception to this definition only occurs when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0051] It should be understood that although the steps in the flowchart in the embodiments of this application are shown sequentially according to the indication of the arrows, these steps are not necessarily executed sequentially according to the order indicated by the arrows. Unless there is a clear indication in this document, the execution of these steps has no strict order limit and can be executed in other orders. Moreover, at least a part of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same moment, but can be executed at different moments, and their execution order is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0052] Depending on the context, the words "if", "when" as used herein may be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" may be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0053] It should be noted that in this text, step codes such as S1 and S2 are used. The purpose is to more clearly and briefly express the corresponding content, and it does not constitute a substantial limitation in terms of sequence. Those skilled in the art may execute S4 first and then S3 during specific implementation, etc., but all these should be within the protection scope of this application.

[0054] It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0055] In the subsequent description, suffixes such as "module", "component", or "unit" used to represent elements are only for the convenience of explaining this application, and they have no specific meaning in themselves. Therefore, "module", "component", or "unit" can be used interchangeably.

[0056] Please refer to Figure 1 , which is a schematic structural diagram of a power system. The power system includes a prime mover 11, a direct-drive hydraulic pump 12, a first hydraulic pump 13, a second hydraulic pump 15, and an actuator (not shown in the figure). The prime mover 11 includes a drive shaft. The direct-drive hydraulic pump 12 is directly connected to the prime mover 11 through a transmission mechanism and is driven by the prime mover 11. The first hydraulic pump 13 is connected in series after the direct-drive hydraulic pump 12, that is, the first hydraulic pump 13 and the direct-drive hydraulic pump 12 are connected to the same drive shaft. The second hydraulic pump 15 is connected to the first hydraulic pump 13 through a transmission mechanism. Here, the prime mover 11 has only one drive shaft, and a direct-drive hydraulic pump 12 is connected to this drive shaft, which is a single-path direct-drive system. The direct-drive hydraulic pump 12 and the first hydraulic pump 13 and / or the second hydraulic pump 15 driven by it form a hydraulic branch. The power system also includes a controller 17 and an electronic control unit 19. The controller 17 is connected to the prime mover 11, and the electronic control unit 19 is connected to the controller 17. Each electronic control unit 19 is connected to a direct-drive hydraulic pump 12 or a first hydraulic pump 13 to control the corresponding hydraulic pump to work. The hydraulic pump connected to the electronic control unit 19 is a controllable hydraulic pump. The second hydraulic pump 15 is not connected to the electronic control unit 19, and this kind of hydraulic pump is an uncontrollable hydraulic pump. It can be understood that the second hydraulic pump 15 can also redistribute its power to other hydraulic pumps.

[0057] Please refer to Figure 2, is a schematic structural diagram of another power system, which includes a prime mover 11, a direct-drive hydraulic pump 12, a first hydraulic pump 13, a second hydraulic pump 15, and an actuator (not shown in the figure). The prime mover 11 includes multiple drive shafts. Multiple direct-drive hydraulic pumps 12 are directly connected to the prime mover 11 through different transmission mechanisms respectively. The first hydraulic pump 13 is connected in series behind the direct-drive hydraulic pump 12. The second hydraulic pump 15 is connected to the first hydraulic pump 13 through a transmission mechanism. Of course, the direct-drive hydraulic pump 12 may not be connected in series with the first hydraulic pump 13, but directly connected to the second hydraulic pump 15. Here, the prime mover 11 includes multiple drive shafts, and multiple direct-drive hydraulic pumps 12 are respectively connected to multiple drive shafts, forming a multi-way direct-drive system. Each direct-drive hydraulic pump 12 and the first hydraulic pump 13 and / or the second hydraulic pump 15 driven by it form a hydraulic branch. The power system also includes a controller 17 and an electronic control unit 19. The controller 17 is connected to the prime mover 11, the electronic control unit 19 is connected to the controller 17, and each electronic control unit 19 is connected to a direct-drive hydraulic pump 12 or a first hydraulic pump 13 to control the corresponding hydraulic pump to work. The hydraulic pump connected to the electronic control unit 19 is a controllable hydraulic pump. The second hydraulic pump 15 is not connected to the electronic control unit 19, and this kind of hydraulic pump is an uncontrollable hydraulic pump. It can be understood that multiple second hydraulic pumps 13 can be connected in series in each hydraulic branch, and the second hydraulic pump 15 can also redistribute its power to other hydraulic pumps. Figure 2 Only one example of the multi-way direct-drive system is shown in. Generally, the multi-way direct-drive system includes both the first hydraulic pump 13 and the second hydraulic pump 15 at the same time, but it may also only include the first hydraulic pump 13 or the second hydraulic pump 15. The numbers of the direct-drive hydraulic pump 12, the first hydraulic pump 13, and the second hydraulic pump 15 can also be set according to needs.

[0058] Such as Figure 3 shown, is a schematic flow diagram of a torque control method for a power system provided by the present invention. This torque control method for the power system is applicable to the above Figure 1 or Figure 2 shown power system. This torque control method for the power system includes:

[0059] S11, determine the allowable torque T of the power system allow .

[0060] S13, obtain the actual consumption torque T of each uncontrollable hydraulic pump realn , and obtain the total actual consumption torque ∑(T realn ) of the uncontrollable hydraulic pumps (that is, the sum of the actual consumption torques T of all uncontrollable hydraulic pumps realn ).

[0061] S15, according to the total actual consumption torque ∑(T realn ) and the allowable torque T allow obtain the total allowable torque T that the controllable hydraulic pumps can usectrl Specifically, the total allowable torque T ctrl is calculated by the formula T allow = T realn - ∑(T ctrl ), that is, the total allowable torque is the difference between the allowable torque and the total actual consumed torque.

[0062] S17. According to the total allowable torque T ctrl and the system predetermined distribution ratio coefficient C, the control target torque T targetn of each controllable hydraulic pump is obtained. Among them, the system predetermined distribution ratio coefficient C can be preset according to system requirements and is dynamically adjustable.

[0063] S19. According to the control target torque T targetn of each controllable hydraulic pump and the real-time outlet pressure P, the target displacement V targetn of each controllable hydraulic pump is calculated, and then the target current i targetn of each controllable hydraulic pump is obtained. Specifically, the target displacement V targetn can be calculated according to the formula V targetn = T mh · 20 · π · η targetn / P, and then the target current i targetn is calculated according to the equation i = f(P, V). In this way, the target current i targetn corresponding to each controllable hydraulic pump can be calculated.

[0064] S21. Control each controllable hydraulic pump according to the target current i targetn . In this way, the control of the limit torque of the power system can be realized. Specifically, when the target current i targetn of the controllable hydraulic pump A is I1, then I1 is used as the control current and input to the controllable hydraulic pump A. When the target current i targetn of the controllable hydraulic pump B is I2, then I2 is used as the control current and input to the controllable hydraulic pump B.

[0065] Specifically, in step S21, the current current of each controllable hydraulic pump is obtained, and the current current is compared with the target current i targetn , and the control current of each controllable hydraulic pump is adjusted according to the difference between the current current and the target current i targetn . In the adjustment of the control current, PID control can be used, or step control can be used.

[0066] For Figure 1 the single-channel direct drive system shown, please refer to Figure 4 and Figure 5 , step S11 specifically includes:

[0067] S112. Obtain the rotational speed n of the prime mover 11, and obtain the maximum output torque T based on the rotational speed n max , and based on the maximum output torque T max and the rational use factor η, obtain the service torque T source .

[0068] Specifically, calculate the maximum output torque T according to the formula T = f(n) max , and according to the formula T source = T max · η to calculate the service torque T source . The rational use factor η is related to the safety reserve of the power system and the basic consumption ratio, etc.

[0069] S114. Obtain the limiting torque T of the direct-drive hydraulic pump 12 limitn . Specifically, obtain the limiting torque T according to the parameter list of the hydraulic pump limitn . Each hydraulic pump has a definite limiting torque T limitn , which is an inherent parameter of the hydraulic pump and can be directly obtained. Since there is only one direct-drive hydraulic pump 12 directly connected to the prime mover 11 in the single-circuit direct-drive system, so T limitn is the total limiting torque ∑T of all direct-drive hydraulic pumps 12 limitn .

[0070] S116. Determine the allowable torque T of the power system according to the service torque T source and the limiting torque T limit . allow .

[0071] Specifically, the allowable torque T allow is the smaller value of the product of the service torque T source multiplied by the transmission ratio i and the limiting torque T limitn , that is, T allow = min(i * T source , T limitn ). The transmission ratio i may exist everywhere in the system and can be incorporated into the calculation according to the torque transmission principle. To simplify the calculation process, the transmission ratio i can be taken as 1. In this way, the allowable torque T allow is the smaller value of the service torque T source and the limiting torque T limitn , that is, T allow = min(T source , T limitn ).

[0072] Specifically, please refer to Figure 6 , which is the pressure-current-displacement curve graph of the electronically controlled double-fold line constant power pump. Please refer to Figure 7 , which is the pressure-current displacement curve graph of the electronically controlled curve constant power pump. Please refer toFigure 8 , which is the current-displacement curve of the electronically controlled displacement pump. Please refer to Figure 9 , which is the pressure-displacement curve of the hydraulically controlled constant power pump. According to the curve, the calculation methods of the output displacement V of different types of hydraulic pumps are different. For the electronically controlled constant power pump and the electronically controlled displacement pump, the outlet pressure P of the hydraulic pump can be collected, and combined with the actual control current i, the output displacement of the hydraulic pump can be calculated according to the formula V = f(P, I); for the hydraulically controlled constant power pump, the outlet pressure P of the hydraulic pump can be collected, and the output displacement of the hydraulic pump can be calculated according to the formula V = f(P). The hydraulically controlled constant power pump is a non-controllable hydraulic pump in this application, so its target current does not need to be obtained in step S23.

[0073] In step S13, specifically, the output displacement V of the non-controllable hydraulic pump can be calculated according to the outlet pressure P of the non-controllable hydraulic pump and the functional relationship between the outlet pressure P and the output displacement V, and then the actual consumption torque T of each non-controllable hydraulic pump can be calculated according to the outlet pressure P and the output displacement V of the non-controllable hydraulic pump realn , and the specific calculation formula can be T realn = P·V / (20·π·η mh ), where π is the pi, and η mh is the mechanical efficiency coefficient of the non-controllable hydraulic pump, and 20·π is a coefficient. If the units of the outlet pressure P and the output displacement V are different, the coefficient is different. In T realn = P·V / (20·π·η mh ), the unit of the outlet pressure P is bar, and the unit of the output displacement V is cubic centimeter. It can be understood that the output displacement V can also be obtained by other means. For example, a flow sensor can be set on the outlet oil path of the hydraulic pump, and combined with the hydraulic pump speed signal, it can be calculated in real time.

[0074] Specifically, in step S17, the control target torque T targetn of each controllable hydraulic pump is the product of the system predetermined distribution ratio coefficient C of this controllable hydraulic pump and the total allowable torque T ctrl , that is, T targetn = C%·T ctrl , and the sum ∑(T targetn ) of the control target torques T targetn of each controllable hydraulic pump is less than or equal to the total allowable torque T ctrl of the controllable hydraulic pump, that is, ∑(T targetn ) ≤ T ctrl . Please refer to Figure 5 , in Figure 1 the single-channel direct drive system shown, the control target torque of the direct drive hydraulic pump 12 is T target1 , and the control target torque of the first hydraulic pump 13 is T target2, the actual consumption torques of the two second hydraulic pumps 15 are T real1 and T real2 .

[0075] For Figure 2 the multi-way direct drive system shown, please refer to Figure 10 and Figure 11 , step S11 specifically includes:

[0076] S112, obtain the rotational speed n of the prime mover 11, obtain the maximum output torque T max from the rotational speed n, and obtain the service torque T max according to the maximum output torque T source .

[0077] Specifically, calculate the maximum output torque T max according to the formula T = f(n), and calculate the service torque T source = T max ·η. The reasonable service factor η is related to the safety reserve of the power system and the basic consumption ratio, etc. source .

[0078] S114, obtain the total limiting torque ∑(T limitn ) of all the direct drive hydraulic pumps 12. Specifically, since there are multiple direct drive hydraulic pumps 12 directly connected to the prime mover 11, the total limiting torque ∑(T limitn ) is the sum of the limiting torques T limitn of multiple direct drive hydraulic pumps 12 directly connected to the prime mover 11. Obtain the limiting torque T limitn according to the parameter list of the hydraulic pump. Each hydraulic pump has a definite limiting torque, which is an inherent parameter of the hydraulic pump and can be directly obtained.

[0079] S116, determine the allowable torque T source of the power system according to the service torque T limit and the total limiting torque T allow .

[0080] Specifically, the allowable torque T allow is the smaller of the product of the service torque T source multiplied by the transmission ratio i and the total limiting torque ∑(T limitn ), that is, T allow = min(i*T source , ∑(T limitn ))), where T allow is the allowable torque T allownThe sum. To simplify the calculation process, the transmission ratio i can be taken as 1. The transmission ratio i may exist in various places in the system and can be incorporated into the calculation according to the torque transmission principle. To simplify the calculation process, the transmission ratio i can be taken as 1. In this way, the allowable torque T allow is the use torque T source and the total limiting torque ∑(T limitn ) of each direct drive hydraulic pump 12, that is, the smaller value, namely T allow = min(T source , ∑(T limitn ))). Among them, the allowable torque T allow is the sum of the allowable torques T allown of all direct drive hydraulic pumps 12.

[0081] Specifically, in a multi-channel direct drive system, the method for obtaining the actual total consumed torque ∑(T realn ) in step S13 is the same as the method for obtaining the actual total consumed torque ∑(T realn ) of a single-channel direct drive system and will not be elaborated here.

[0082] Specifically, in a multi-channel direct drive system, in step S17, in addition to satisfying T targetn = C%·T ctrl , and ∑(T targetn ) ≤ T ctrl , it is also necessary to satisfy: for each direct drive hydraulic pump 12, the sum of the control target torque T targetn of this direct drive hydraulic pump 12 and all controllable hydraulic pumps driven by it and the sum of the actual consumed torque T realn of all non-controllable hydraulic pumps driven by it is less than or equal to the smaller value of the use torque T source and the limiting torque T limitn of this direct drive hydraulic pump 12, that is, for each hydraulic branch, ∑(T targetn ) + ∑(T realn ) ≤ min(T source , T limitn ). Please refer to Figure 11 , in Figure 2 the multi-channel direct drive system shown, the limiting torque of the direct drive hydraulic pump 12 on the first branch is T limit1 , the control target torque of the direct drive hydraulic pump 12 is T target11 , the control target torque of the first hydraulic pump 13 is T target12 , the actual consumed torques of the two second hydraulic pumps 15 are T real11 and T real12 respectively, the control target torque of the direct drive hydraulic pump 12 on the second branch is T target21 , the control target torque of the first hydraulic pump 13 is T target22, the actual consumption torques of the two second hydraulic pumps 15 are T real21 and T real22 . That is to say, T target11 +T target12 +T real11 +T real12 ≤min(T source ,T limit1 ), T target21 +T target22 +T real21 +T real22 ≤min(T source ,T limit2 ).

[0083] As Figure 12 shown, it is a schematic structural diagram of the torque control system of the power system provided by the present invention. The torque control system of the power system includes:

[0084] An acquisition module 51, which is used to acquire the rotational speed n of the prime mover, the real-time outlet pressure P of the hydraulic pump, and is used to obtain the limit torque T limitn of the direct-drive hydraulic pump 12;

[0085] A data processing module 53, which is used to determine the allowable torque T allow of the power system, obtain the actual consumption torques T realn of each non-controllable hydraulic pump, and obtain the total actual consumption torque ∑(T realn ). According to the total actual consumption torque ∑(T realn ) and the allowable torque T allow , obtain the total allowable torque T ctrl that can be used by the controllable hydraulic pump. According to the total allowable torque T ctrl , obtain the control target torque T targetn of each controllable hydraulic pump. According to the control target torque T targetn of each controllable hydraulic pump and the real-time outlet pressure P, calculate the target displacement V targetn of each controllable hydraulic pump, and further obtain the target current i targetn of each controllable hydraulic pump; among them, the total allowable torque T ctrl is the difference between the allowable torque T allow and the total actual consumption torque ∑(T realn ).

[0086] A control module 55, which controls each controllable hydraulic pump according to the target current i targetn .

[0087] Specifically, for a single-channel direct-drive power system, the data processing module 53 determines the allowable torque T allowSpecifically, it includes: obtaining the maximum output torque T of the prime mover according to the rotational speed n of the prime mover max , and according to the maximum output torque T max and the rational utilization factor η to obtain the service torque T source , according to the service torque T source , the limiting torque T limitn and the transmission ratio i to determine the allowable torque T of the power system allow , where the allowable torque T allow is the smaller value of the product of the service torque T source multiplied by the transmission ratio i and the limiting torque T limitn , that is, T allow = min(i * T source , T limitn ), the transmission ratio i may exist in various places in the system, and can be incorporated into the calculation according to the torque transmission principle. To simplify the calculation process, the transmission ratio i can be taken as 1. In this way, the allowable torque T allow is the smaller value of the service torque T source and the limiting torque T limit , that is, T allow = min(T source , T limit ). More specifically, the maximum output torque T is calculated according to the formula T = f(n) max , and the service torque T is calculated according to the formula T source = T max ·η source . The rational utilization factor η is related to the safety reserve of the power system and the basic consumption ratio, etc.

[0088] Specifically, for a single - path direct - drive power system, the data processing module 53 obtains the control target torque T of each controllable hydraulic pump according to the total allowable torque T ctrl Specifically, it includes: the data processing module 53 is used to make the control target torque T of each controllable hydraulic pump targetn be the product of the system - predetermined allocation ratio coefficient C of this controllable hydraulic pump and the total allowable torque T targetn , and the sum ∑(T ctrl ) of the control target torques T of each controllable hydraulic pump is less than or equal to the total allowable torque T targetn targetn ctrl allow max .

[0089] Specifically, for a multi - path direct - drive power system, the data processing module 53 determines the allowable torque T of the power system allow Specifically, it includes: obtaining the maximum output torque T of the prime mover according to the rotational speed n of the prime mover max , and according to the maximum output torque T max and the rational utilization factor η to obtain the service torque Tsource , according to the limiting torque T limitn , the total limiting torque ∑(T limitn ) of all direct-drive hydraulic pumps 12 is obtained. According to the operating torque T source , the total limiting torque T limit , and the transmission ratio i, the allowable torque T allow of the power system is determined. Among them, the allowable torque T allow is the product of the operating torque T source and the smaller value of the transmission ratio i and the total limiting torque T limit , that is, T allow = min(i * T source , ∑(T limitn ))). The allowable torque T allow is the sum of the allowable torques T allown of all the first hydraulic pumps 13 directly connected to the prime mover 11, that is, T allow = ∑(T allown ). The transmission ratio i may exist in various places in the system and can be incorporated into the calculation according to the torque transmission principle. To simplify the calculation process, the transmission ratio i can be taken as 1. In this way, the allowable torque T allow is the smaller value of the operating torque T source and the total limiting torque T limit , that is, T allow = min(T source , ∑(T limitn )). More specifically, the maximum output torque T max is calculated according to the formula T = f(n), and the operating torque T source is calculated according to the formula T max = T source ·η. The reasonable utilization factor η is related to the safety reserve of the power system and the basic consumption ratio, etc.

[0090] Specifically, for a multi-way direct-drive power system, the data processing module 53 obtains the control target torque T ctrl of each controllable hydraulic pump according to the total allowable torque T targetn . Specifically, it includes: the data processing module 53 is used to make the control target torque T targetn of each controllable hydraulic pump be the product of the system predetermined allocation ratio coefficient C of this controllable hydraulic pump and the total allowable torque T ctrl , and the sum ∑(T targetn ) of the control target torques T targetn of each controllable hydraulic pump is less than or equal to the total allowable torque T ctrl . And on each hydraulic branch, the sum of the control target torques T targetn of the direct-drive hydraulic pump 12 and all the controllable hydraulic pumps driven by it and the actual consumption torque T of all the non-controllable hydraulic pumps driven by itrealn The sum of the sums is less than or equal to the smaller of the torque T used source and the limiting torque T of the direct drive hydraulic pump 12 limitn .

[0091] Specifically, the total actual consumed torque ∑(T realn ) is equal to the actual consumed torque T of multiple non - controllable hydraulic pumps reanl . Specifically, the acquisition module 51 acquires the outlet pressure P of the non - controllable hydraulic pump. The data processing module 53 calculates the output displacement V of the non - controllable hydraulic pump according to the functional relationship between the outlet pressure P and the output displacement V of the non - controllable hydraulic pump, and then calculates the actual consumed torque T of each non - controllable hydraulic pump according to the outlet pressure P and the output displacement V realn , and the specific calculation formula can be T realn = P·V / (20·π·η mh ), where π is the pi, η mh is the mechanical efficiency coefficient of the non - controllable hydraulic pump, 20·π is a coefficient. If the units of the outlet pressure P and the output displacement V are different, the coefficient is different. In T real = P·V / (20·π·η mh ), the unit of the outlet pressure P is bar, and the unit of the output displacement V is cubic centimeter. It can be understood that the output displacement V can also be obtained by setting a flow sensor on the outlet oil path of the hydraulic pump and combining with the hydraulic pump speed signal for real - time calculation

[0092] Specifically, the calculation methods of the output displacement V of different types of hydraulic pumps are different. For the electronically controlled constant power pump and the electronically controlled displacement pump, the outlet pressure P of the hydraulic pump can be acquired, and combined with the actual control current i, the output displacement of the hydraulic pump can be calculated according to the formula V = f(P, I); for the hydraulically controlled constant power pump, the outlet pressure P of the hydraulic pump can be acquired, and the output displacement of the hydraulic pump can be calculated according to the formula V = f(P). The hydraulically controlled constant power pump is a non - controllable hydraulic pump in this application

[0093] Specifically, the data processing module 53 calculates the allowable total torque T ctrl through the formula T allow = T realn - ∑(T ctrl ).

[0094] Specifically, the target displacement V targetn can be calculated according to the formula V targetn = T mh ·20·π·η targetn / P, and then the target current i targetn can be calculated according to the equation i = f(P, V)

[0095] Specifically, the current current of each controllable hydraulic pump can be obtained, and the current current is compared with the target current i targetn , and the control current of each controllable hydraulic pump is adjusted according to the difference between the current current and the target current i targetn . In the adjustment of the control current, PID control can be adopted, or step control can be adopted.

[0096] In the torque control method and system of the power system of the present invention, torque control is performed on the controllable hydraulic pump, so as to ensure the total controlled torque, ensure that the drive shaft of the controllable hydraulic pump does not exceed the limit torque, and ensure that the total torque of the power system does not exceed the total allowable use torque, thereby ensuring the reliability and safety of the power system.

[0097] The above is only the specific implementation manner of the present application. The above scenarios are only examples and do not constitute a limitation on the application scenarios of the technical solutions provided by the embodiments of the present application. The technical solutions of the present application can also be applied to other scenarios. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered by the protection scope of the present application. Therefore, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0098] In the present application, for the description of the same or similar term concepts, technical solutions and / or application scenarios, generally only the first occurrence is described in detail. When it appears repeatedly later, for the sake of brevity, it is generally not described again. When understanding the technical solutions and other contents of the present application, for the same or similar term concepts, technical solutions and / or application scenarios that are not described in detail later, reference can be made to the relevant detailed descriptions before.

Claims

1. A torque control method for a power system, applicable to a power system, the power system comprising a prime mover (11), a direct drive hydraulic pump (12), a first hydraulic pump (13) and a second hydraulic pump (15), one or more of the direct drive hydraulic pumps (12) being directly connected to the prime mover (11), the first hydraulic pump (13) being connected in series after the direct drive hydraulic pump (12), the second hydraulic pump (15) being connected to the first hydraulic pump (13), the direct drive hydraulic pump (12) and the first hydraulic pump (13) being controllable hydraulic pumps, the second hydraulic pump (15) being a non-controllable hydraulic pump, each direct drive hydraulic pump (12) and the first hydraulic pump (13) and / or the second hydraulic pump (15) driven thereby forming a hydraulic branch, characterized in that, The torque control method for the power system includes: Determine the allowable torque (T allow ) of the power system; Obtain the actual consumed torque (T realn ) of the non-controllable hydraulic pump, and obtain the total actual consumed torque (Σ(T realn )) of all the non-controllable hydraulic pumps; According to the total actual consumed torque (Σ(T realn )) and the allowable torque (T allow ), obtain the total allowable torque (T ctrl ) that the controllable hydraulic pump is allowed to use: The total allowable torque (T ctrl ) is the difference between the allowable torque (T allow ) and the total actual consumed torque (Σ(T realn )); According to the total allowable torque (T ctrl ), and the system predetermined allocation ratio coefficient (C), the control target torque (T targetn ) of each controllable hydraulic pump is obtained; According to the control target torque (T targetn ) and the real-time outlet pressure (P) of the controllable hydraulic pump, calculate the target displacement (V targetn ) of each controllable hydraulic pump, and further obtain the target current (i targetn ) of the controllable hydraulic pump; Control the controllable hydraulic pump according to the target current (i targetn ); Among them, the power system is a single-path direct drive type, and the steps of determining the allowable torque (T allow ) specifically include: obtaining the rotational speed (n) of the prime mover (11), obtaining the maximum output torque (T max ) according to the rotational speed (n), and multiplying the maximum output torque (T max ) by a reasonable utilization factor (η) to obtain the utilization torque (T source ); obtaining the limiting torque (T limitn ) of the direct drive hydraulic pump (12); determining the allowable torque (T source ) of the power system according to the utilization torque (T limitn ) and the limiting torque (T allow ), wherein the allowable torque (T allow ) is the smaller value of the utilization torque (T source ) and the limiting torque (T limitn ); or, the power system is a multi-path direct drive type, and the steps of determining the allowable torque (T allow ) of the power system specifically include: obtaining the rotational speed (n) of the prime mover (11), obtaining the maximum output torque (T max ) according to the rotational speed (n), and multiplying the maximum output torque (T max ) by a reasonable utilization factor (η) to obtain the utilization torque (T source ); obtaining the total limiting torque (Σ(T limitn )) of all the direct drive hydraulic pumps (12); determining the allowable torque (T source ) of the power system according to the utilization torque (T limitn ) and the total limiting torque (Σ(T allow ), wherein the allowable torque (T allow ) is the smaller value of the utilization torque (T source ) and the total limiting torque (Σ(T limitn )); Step of obtaining the actual consumed torque (T realn ) of the uncontrollable hydraulic pump specifically includes: calculating the output displacement (V) of the uncontrollable hydraulic pump according to the functional relationship between the outlet pressure (P) and the output displacement (V) of the uncontrollable hydraulic pump, and then calculating the actual consumed torque (T realn ) of the uncontrollable hydraulic pump based on the outlet pressure (P) and the output displacement (V) of the uncontrollable hydraulic pump; or, obtaining the output displacement (V) of the uncontrollable hydraulic pump by setting a flow sensor on the uncontrollable hydraulic pump and performing real-time calculation in combination with the rotational speed (n) of the uncontrollable hydraulic pump, and then calculating the actual consumed torque (T realn ) of the uncontrollable hydraulic pump according to the outlet pressure (P) and the output displacement (V) of the uncontrollable hydraulic pump.

2. The torque control method of the power system according to claim 1, characterized in that, When the power system is a single-channel direct drive type, obtaining the control target torque (T targetn ) of each controllable hydraulic pump specifically includes: the control target torque (T targetn ) of each controllable hydraulic pump is the product of the system predetermined allocation ratio coefficient (C) of this controllable hydraulic pump and the total allowable torque (T ctrl ), and the sum (Σ(T targetn )) of the control target torque (T targetn ) of each controllable hydraulic pump is less than or equal to the total allowable torque (T ctrl ).

3. The torque control method of the power system according to claim 1, characterized in that, When the power system is a multi-channel direct drive type, obtaining the control target torque (T targetn ) of each of the controllable hydraulic pumps specifically includes: the control target torque (T targetn ) of each of the controllable hydraulic pumps is the product of the system predetermined allocation ratio coefficient (C) of this controllable hydraulic pump and the total allowable torque (T ctrl ), and the sum (Σ(T targetn )) of the control target torques (T targetn ) of each of the controllable hydraulic pumps is less than or equal to the total allowable torque (T ctrl ); on each of the hydraulic branches, the sum of the control target torques of the direct drive hydraulic pump (12) and all the controllable hydraulic pumps driven by it and the sum of the actual consumption torques of all the non-controllable hydraulic pumps driven by it is less than or equal to the smaller of the service torque (T source ) and the limit torque (T limitn ) of the direct drive hydraulic pump (12).

4. The torque control method for the power system according to claim 1, wherein The step of controlling the controllable hydraulic pump according to the target current (i targetn ) specifically includes: obtaining the current current of the controllable hydraulic pump, comparing the current current with the target current (i targetn ), and adjusting the control current of the controllable hydraulic pump according to the difference between the current current and the target current (i targetn ).

5. A torque control system for a power system, applicable to a power system, the power system including a prime mover (11), a direct drive hydraulic pump (12), a first hydraulic pump (13) and a second hydraulic pump (15), one or more of the direct drive hydraulic pumps (12) being directly connected to the prime mover (11), the first hydraulic pump (13) being connected in series behind the direct drive hydraulic pump (12), the second hydraulic pump (15) being connected to the first hydraulic pump (13), the direct drive hydraulic pump (12) and the first hydraulic pump (13) being controllable hydraulic pumps, the second hydraulic pump (15) being a non - controllable hydraulic pump, each direct drive hydraulic pump (12) and the first hydraulic pump (13) and / or the second hydraulic pump (15) driven by it forming a hydraulic branch, characterized in that, The torque control system for the power system includes: The acquisition module (51) is configured to acquire the rotational speed (n) of the prime mover, the real-time outlet pressures (P) of the first hydraulic pump (13) and the second hydraulic pump (15), and to obtain the limiting torque (T limitn ) of the direct drive hydraulic pump (12). A data processing module (53) for determining the allowable torque (T allow ) of the power system, obtaining the actual consumption torque (T realn ) of the non-controllable hydraulic pump, and obtaining the total actual consumption torque (Σ(T realn )) of all the non-controllable hydraulic pumps. According to the total actual consumption torque (Σ(T realn )) and the allowable torque (T allow ), obtaining the total allowable torque (T ctrl ) that the controllable hydraulic pump is allowed to use: The total allowable torque (T ctrl ) is the difference between the allowable torque (T allow ) and the total actual consumption torque (∑(T realn ). According to the total allowable torque (T ctrl ), obtaining the control target torque (T targetn ) of the controllable hydraulic pump. According to the control target torque (T targetn ) and the real-time outlet pressure (P) of the controllable hydraulic pump, calculating the target displacement (V targetn ) of the controllable hydraulic pump, and further obtaining the target current (i targetn ) of the controllable hydraulic pump; The control module (55) controls the controllable hydraulic pump according to the target current (i targetn ). Among them, the power system is a single - path direct - drive type, and the data processing module (53) determines the allowable torque (T allow ) specifically includes: obtaining the maximum output torque (T max ) of the prime mover according to the rotational speed (n) of the prime mover, and multiplying the maximum output torque (T max ) by the rational use factor (η) to obtain the service torque (T source ), determining the allowable torque (T source ) of the power system according to the service torque (T limitn ) and the limit torque (T allow ), the allowable torque (T allow ) being the smaller of the service torque (T source ) and the limit torque (T limitn ), and the data processing module (53) obtaining the control target torque (T targetn ) of each controllable hydraulic pump according to the total allowable torque (Tctrl) specifically includes: the data processing module (53) is used to make the control target torque (T targetn ) of each controllable hydraulic pump be the product of the system - predetermined distribution ratio coefficient (C) of this controllable hydraulic pump and the total allowable torque (T ctrl ); or, the power system is a multi - path direct - drive type, and the data processing module (53) determining the allowable torque (T allow ) of the power system specifically includes: obtaining the maximum output torque (T max ) of the prime mover according to the rotational speed (n) of the prime mover, and obtaining the service torque (T max ) according to the maximum output torque (T source ) and the rational use factor (η), obtaining the total limit torque (∑(T limitn )) of all the direct - drive hydraulic pumps (12) according to the limit torque (T limitn ), determining the allowable torque (T source ) of the power system according to the service torque (T limitn ) and the total limit torque (∑(T allow )): the allowable torque (T allow ) being the smaller of the service torque (T source ) and the total limit torque (∑T limitn ); among them, the allowable torque (T allow ) is the sum of the allowable torques (T allown ) of all the direct - drive hydraulic pumps (12), and the data processing module (53) obtaining the control target torque (T ctrl ) of each controllable hydraulic pump according to the total allowable torque (T targetn )Specifically, the data processing module (53) is used to make the control target torque (T targetn ) of each of the controllable hydraulic pumps be the product of the system predetermined allocation ratio coefficient (C) of the controllable hydraulic pump and the total allowable torque (T ctrl ) 6. The torque control system of the power system according to claim 5, characterized in that, When the power system is a single-path direct drive type, the sum (∑(T targetn )) of the control target torques (T targetn ) of each of the controllable hydraulic pumps is less than or equal to the total allowable torque (T ctrl ).

7. The torque control system of the power system according to claim 5, characterized in that When the power system is a multi-channel direct drive type, the sum (∑(T targetn )) of the control target torques (T targetn ) of each controllable hydraulic pump is less than or equal to the total allowable torque (T ctrl ), and on each hydraulic branch, the sum of the control target torques of the direct drive hydraulic pump (12) and all the controllable hydraulic pumps driven by it and the sum of the actual consumed torques of all the non-controllable hydraulic pumps driven by it is less than or equal to the smaller of the service torque (T source ) and the limit torque (T limitn ) of the direct drive hydraulic pump (12).

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