CN103016326B - Method and system for controlling variable output pump assembly, and engineering machinery - Google Patents

Abstract

The invention discloses a method and a system for controlling a variable output pump assembly, wherein the variable output pump assembly is formed by connecting n variable output pumps in parallel; according to a target output volume q of the variable output pump assembly, under a predetermined working pressure p, a functional relation between the efficiency e of the variable output pump assembly and the target outputs q1, q2, ellipsis, qn of the n variable output pumps is constructed; according to the functional relation, the target outputs q1, q2, ellipsis, qn of the n variable output pumps under the maximum efficiency max(e) of the variable output pump assembly is worked out through a optimization algorithm; and moreover, the n variable output pumps in the variable output pump assembly are controlled to run under the target outputs q1, q2, ellipsis, qn. In such a way, the efficiency and the service life of the variable output pump assembly are improved and prolonged respectively. The invention also provides engineering machinery comprising a control system of the variable output pump assembly.

Description

A kind of controlling method of variable displacement pump group and system, engineering machinery

Technical field

The present invention relates to hydraulic pump control technical field, particularly a kind of controlling method of variable displacement pump group and system, and apply the engineering machinery of control system of above-mentioned variable displacement pump group.

Background technique

At present, widely, the hydraulic system applying this variable displacement pump group can realize large-scale stepless time adjustment to the application area of electric proportional variable pump group, and driving torque is large, is hydraulic system conventional in engineering machinery field.

How better the efficiency of variable displacement pump group is one of its important performance index, the working state of multiple variable displacement pump in controlled variable pump group, for promoting the efficiency of whole variable displacement pump group and having very important significance working life.

In traditional control mode, electric proportional variable pump group generally adopts synchronous impartial control mode, and namely in variable displacement pump group, the displacement size of each variable displacement pump is equal and its change regulative mode is consistent.In working procedure, the displacement size of multiple variable displacement pump is equal, its drawback is just, under a lot of operating mode, multiple variable displacement pump is all operated in small displacement scope, and the leakage of variable displacement pump is very serious, friction and to send out loss thermogenetic very large, reduce volumetric efficiency and the mechanical efficiency of variable displacement pump significantly, thus reduce the efficiency of whole variable displacement pump group; Further, multiple variable displacement pump synchronous working in variable displacement pump group, each variable displacement pump can produce corresponding life consumption in the course of the work, thus reduces the working life of each variable displacement pump, eventually reduces the working life of whole variable displacement pump group.

Therefore, how the control mode of design variable pump group, to improve efficiency and the working life of variable displacement pump group, just becomes those skilled in the art's technical issues that need to address.

Summary of the invention

The present invention proposes a kind of controlling method and system of variable displacement pump group, improve efficiency and the working life of variable displacement pump group.The invention allows for a kind of engineering machinery comprising the control system of above-mentioned variable displacement pump group.

On the one hand, the present invention proposes a kind of controlling method of variable displacement pump group, described variable displacement pump group is formed in parallel by n variable displacement pump, n >=2, and described controlling method comprises:

According to the target discharge capacity q of described variable displacement pump group, under predetermined working pressure p, build efficiency e and n variable pump delivery q of described variable displacement pump group ₁, q ₂..., q _nfunctional relation:

$\left\{\begin{array}{c}\max \left(e\right)=\max [f\left(q_1\right)\×\left(q_2\right)\×...\×f\left(q_n\right)]\\ f\left(0\right)=1\\ q=q_1+q_2+...+q_n\\ 0\≤q_1\≤q_{1\max },0\≤q_2\≤q_{2\max },...,0\≤q_n\≤q_{n\max }\end{array}\right.$

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump;

According to above-mentioned functional relation, calculated the target discharge capacity q of described variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and to control in described variable displacement pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

Preferably, described variable displacement pump is electric proportional variable pump, according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, and to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _nwith control n electric proportional variable pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

Preferably, at q < q _1max+ q _2max+ ...+q _nmaxwhen; The alternation time T of design variables pump group, or, according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T; When described variable displacement pump group operation reaches alternation time T, control n variable displacement pump alternation in described variable displacement pump group.

Preferably, according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, the life consumption threshold value Δ s of design variables pump _t, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of described variable displacement pump group is defined as alternation time T.

Preferably, according to the working pressure p of described variable displacement pump group, the target discharge capacity q of operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nwith t working time, determine the life consumption Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, wherein,

Δs ₁＝G(p，r，q ₁，t)、Δs ₂＝G(p，r，q ₂，t)、…、Δs _n＝G(p，r，q _n，t)。

On the other hand, the invention allows for a kind of control system of variable displacement pump group, described variable displacement pump group is formed in parallel by n variable displacement pump, n >=2, and described control system comprises controller, and controller is connected with n variable displacement pump in described variable displacement pump group;

According to the target discharge capacity q of described variable displacement pump group, under predetermined working pressure p, described controller builds efficiency e and n variable pump delivery q of described variable displacement pump group ₁, q ₂..., q _nfunctional relation:

$\left\{\begin{array}{c}\max \left(e\right)=\max [f\left(q_1\right)\&times;\left(q_2\right)\&times;...\&times;f\left(q_n\right)]\\ f\left(0\right)=1\\ q=q_1+q_2+...+q_n\\ 0\&le;q_1\&le;q_{1\max },0\&le;q_2\&le;q_{2\max },...,0\&le;q_n\&le;q_{n\max }\end{array}\right.$

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump;

Described controller, according to above-mentioned functional relation, calculates the target discharge capacity q of described variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and to control in described variable displacement pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

Preferably, described variable displacement pump is electric proportional variable pump, and described controller is according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, and to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _nwith control n electric proportional variable pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

Preferably, at q < q _1max+ q _2max+ ...+q _nmaxwhen; The alternation time T of design variables pump group in the controller, or described controller is according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T; When described variable displacement pump group operation reaches alternation time T, described controller can control n variable displacement pump alternation in described variable displacement pump group.

Preferably, described controller is according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, the life consumption threshold value Δ s of design variables pump _t, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of described variable displacement pump group is defined as alternation time T by described controller.

Preferably, the working pressure p of described controller according to described variable displacement pump group, the target discharge capacity q of operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nwith t working time, determine the life consumption Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, wherein,

Δs ₁＝G(p，r，q ₁，t)、Δs ₂＝G(p，r，q ₂，t)、…、Δs _n＝G(p，r，q _n，t)。

In the present invention, according to the variable displacement pump group target discharge capacity q meeting the requirement of hydraulic system current work, calculated the target discharge capacity q of n variable displacement pump by optimizing algorithm ₁, q ₂..., q _n, q=q ₁+ q ₂+ ...+q _n, in variable displacement pump group, n variable displacement pump operates in target discharge capacity q ₁, q ₂..., q _nunder, variable displacement pump group works under being in maximal efficiency.Like this, according to the variable displacement pump group target discharge capacity q meeting the requirement of hydraulic system current work, obtain the target discharge capacity of variable displacement pump group n variable displacement pump under maximal efficiency, achieve the maximizing efficiency of variable displacement pump group by the control mode of n variable displacement pump discharge capacity in dynamic adjustments variable displacement pump group; Synchronous impartial control mode in prior art, reduces the phenomenon such as leakage and loss of variable displacement pump group, improve variable displacement pump group efficiency, and dynamic adjustments control mode can improve the working life of variable displacement pump group.

Another aspect, the invention allows for a kind of engineering machinery, comprises variable displacement pump group, also comprises the control system of above-mentioned variable displacement pump group.

Based on the technique effect of the control system of above-mentioned variable displacement pump group, the engineering machinery comprising the control system of this variable displacement pump group has above-mentioned technique effect too.

Accompanying drawing explanation

The accompanying drawing forming a part of the present invention is used to provide a further understanding of the present invention, and schematic description and description of the present invention, for explaining the present invention, does not form inappropriate limitation of the present invention.

Fig. 1 is the structure principle chart of the control system of a kind of variable displacement pump group that the present invention proposes.

Embodiment

Core concept of the present invention is the controlling method and the system that propose a kind of variable displacement pump group, to improve efficiency and the working life of variable displacement pump group; Further, the present invention also proposes a kind of engineering machinery comprising the control system of above-mentioned variable displacement pump group.

It should be noted that, when not conflicting, the embodiment in the present invention and the feature in embodiment can combine mutually.Below with reference to the accompanying drawings and describe the present invention in detail in conjunction with the embodiments.

As shown in Figure 1, Fig. 1 is the structure principle chart of the control system of a kind of variable displacement pump group that the present invention proposes.

In variable displacement pump, the efficiency of variable displacement pump depends primarily on working pressure and discharge capacity, and under predetermined working pressure, variable pump delivery is the principal element affecting its efficiency.

In the present invention, variable displacement pump group is formed in parallel by n variable displacement pump, then:

The efficiency of variable displacement pump and the pass of discharge capacity are: e ₁=f (q ₁), e ₂=f (q ₂) ..., e _n=f (q _n),

The pass of the discharge capacity of variable displacement pump group and n variable pump delivery is: q=q ₁+ q ₂+ ...+q _n,

The pass of the efficiency of the efficiency of variable displacement pump group and n variable displacement pump is: e=e ₁× e ₂× ... × e _n,

Wherein, e ₁, e ₂..., e _nbe respectively the efficiency of n variable displacement pump, q ₁, q ₂..., q _nbe respectively the discharge capacity of the efficiency of n variable displacement pump, q is the discharge capacity of variable displacement pump group, and e is the efficiency of variable displacement pump group.

With reference to Fig. 1, the control system of a kind of variable displacement pump group that the present invention proposes, comprise controller and variable displacement pump group, variable displacement pump group is formed in parallel by n variable displacement pump, n >=2, and controller is used for:

According to the target discharge capacity q of variable displacement pump group, under predetermined working pressure p, controller builds efficiency e and n variable pump delivery q of variable displacement pump group ₁, q ₂..., q _nfunctional relation:

max(e)＝max[e ₁×e ₂×...×e _n]＝max[f(q ₁)×f(q ₂)×...×f(q _n)]

The boundary conditions of this functional relation is:

f(0)＝1，

q＝q ₁+q ₂+...+q _n，

0≤q ₁≤q _1max，0≤q ₂≤q _2max，...，0≤q _n≤q _nmax，

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump;

According to above-mentioned functional relation, controller calculates the target discharge capacity q of variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and in controlled variable pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

In this example, require that (traffic demand) obtains the target discharge capacity q of variable displacement pump group according to the current work of hydraulic system, controller calculates the target discharge capacity q of n variable displacement pump by optimizing algorithm ₁, q ₂..., q _n, wherein, q=q ₁+ q ₂+ ...+q _n, make n variable displacement pump in variable displacement pump group operate in target discharge capacity q ₁, q ₂..., q _nunder, under variable displacement pump group is operated in maximal efficiency.Like this, meeting the variable displacement pump group target discharge capacity q of hydraulic system current work requirement, obtain the target discharge capacity of variable displacement pump group n variable displacement pump under maximal efficiency, achieve the maximizing efficiency of variable displacement pump group by the control mode of n variable displacement pump discharge capacity in dynamic adjustments variable displacement pump group; Synchronous impartial control mode in prior art, reduces the phenomenon such as leakage and loss of variable displacement pump group, improve variable displacement pump group efficiency, and dynamic adjustments control mode improves the working life of variable displacement pump group.

Such as, according to the variable displacement pump group target discharge capacity q meeting the requirement of hydraulic system current work, when adopting synchronous impartial control mode in prior art, in variable displacement pump group, the displacement size of n variable displacement pump is equal, and be all in small displacement operating range, its leakage phenomenon is very serious, and the loss that friction and heating cause is very large, and the efficiency of variable displacement pump group is extremely low, when adopting the control system of above-mentioned variable displacement pump group of the present invention, the target discharge capacity of variable displacement pump group n variable displacement pump under maximal efficiency can be obtained, when wherein one or two variable pump delivery can meet the variable displacement pump group target discharge capacity q of hydraulic system current work requirement, and under variable displacement pump group is in maximal efficiency, can control other variable pump deliveries is zero, i.e. closed portion variable displacement pump, like this, achieve the maximizing efficiency of variable displacement pump group, and be in the Partial Variable pump not generation time loss of closed condition in variable displacement pump group, the working life of variable displacement pump group can be improved.

In a particular embodiment, above-mentioned variable displacement pump group is formed in parallel by n electric proportional variable pump, and based on the electric proportionality of variable displacement pump, controller can according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, in control operation, controller is respectively to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _n, thus control n electric proportional variable pump is at target discharge capacity q ₁, q ₂..., q _nlower operation.

In actual application, under a lot of operating mode, in variable displacement pump group, n variable displacement pump is not operate at full capacity completely, i.e. the discharge capacity q < q of variable displacement pump group _1max+ q _2max+ ...+q _nmaxnow, in variable displacement pump group, the life consumption of n variable displacement pump there are differences, namely the life consumption of Partial Variable pump is larger, and the life consumption of another part variable displacement pump is less, especially, when Partial Variable pump is in running order, Partial Variable pump is in closed condition, the life consumption of the variable displacement pump under in running order is very large, and the variable displacement pump being in closed condition does not have life consumption; Normal this in the past, first the variable displacement pump that life consumption is larger can lose efficacy, and is formed " short slab " of whole variable displacement pump group, and the overall losses of variable displacement pump group increases, thus have impact on the working life of whole variable displacement pump group.

In order to reduce the overall losses of variable displacement pump group, making whole variable displacement pump group have longer working life, substantially equal working life can be had by n variable displacement pump in controlled variable pump group, eliminating " short slab " effect; For this reason, under the prerequisite meeting the requirement of operation horizontal stability, n variable displacement pump alternation in controlled variable pump group, like this, pass through alternate mode, in variable displacement pump group, n variable displacement pump can have substantially equal working life, thus reduces the overall losses of variable displacement pump group, improves the working life of whole variable displacement pump group.

Particularly, by setting alternation time T, when the operation of variable displacement pump group reaches alternation time T, n variable displacement pump alternation in controlled variable pump group.

In a kind of embodiment, at q < q _1max+ q _2max+ ...+q _nmaxwhen, the alternation time T of design variables pump group in the controller, when the operation of variable displacement pump group reaches alternation time T, n variable displacement pump alternation in controller controlled variable pump group.

In this example, the alternation time T of variable displacement pump can be preset according to parameters such as the running parameter of variable displacement pump, field working conditions condition, construction periods.

In another kind of embodiment, at q < q _1max+ q _2max+ ...+q _nmaxwhen, controller is according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T; When the operation of variable displacement pump group reaches alternation time T, n variable displacement pump alternation in controller controlled variable pump group.

Particularly, the life consumption threshold value Δ s of design variables pump in the controller _t, and controller can according to the target discharge capacity q of the working pressure p of variable displacement pump group, operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nthe life consumption Δ s of n variable displacement pump is determined with t working time ₁, Δ s ₂..., Δ s _n,

Δs ₁＝G(p，r，q ₁，t)、Δs ₂＝G(p，r，q ₂，t)、…、Δs _n＝G(p，r，q _n，t)，

Wherein, life consumption threshold value Δ s _tcan determine according to parameters such as the running parameter of variable displacement pump, field working conditions condition, construction periods, working pressure p can adopt the pressure of hydraulic oil, and operating ambient temperature r can adopt the temperature of hydraulic oil; Like this, controller in the process determining alternation time T, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of variable displacement pump group is defined as alternation time T.

In the present invention, when the operation of variable displacement pump group reaches alternation time T, n variable displacement pump alternation in controller controlled variable pump group, particularly, n variable displacement pump alternation comprises multiple situation: no matter the size of n its life consumption of variable displacement pump, can work, such as according to the job order cycle alternation of setting, sequence can be numbered to n variable displacement pump, and the cycle alternation work in order of a control n variable displacement pump; Or, the variable displacement pump that in n variable displacement pump, life consumption is maximum and the minimum variable displacement pump alternation of life consumption, advance to intermediate range successively, and can control the mediate variable displacement pump of scope of life consumption and keep working state constant, etc., do not enumerate one by one at this.

By n variable displacement pump alternation in controlled variable pump group, in variable displacement pump group, n variable displacement pump can have substantially equal working life, especially when to Partial Variable pump is in running order, Partial Variable pump is in closed condition, alternation is carried out by between working state and the variable displacement pump of closed condition, thus reduce the overall losses of variable displacement pump group, considerably improve the working life of whole variable displacement pump group.

The invention allows for a kind of controlling method of variable displacement pump group, described variable displacement pump group is formed in parallel by n variable displacement pump, and described controlling method comprises:

According to the target discharge capacity q of described variable displacement pump group, under predetermined working pressure p, build efficiency e and n variable pump delivery q of described variable displacement pump group ₁, q ₂..., q _nfunctional relation:

$\left\{\begin{array}{c}\max \left(e\right)=\max [f\left(q_1\right)\&times;\left(q_2\right)\&times;...\&times;f\left(q_n\right)]\\ f\left(0\right)=1\\ q=q_1+q_2+...+q_n\\ 0\&le;q_1\&le;q_{1\max },0\&le;q_2\&le;q_{2\max },...,0\&le;q_n\&le;q_{n\max }\end{array}\right.$

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump;

According to above-mentioned functional relation, calculated the target discharge capacity q of described variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and to control in described variable displacement pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

In a particular embodiment, described variable displacement pump group is formed in parallel by n electric proportional variable pump, in control operation process, according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, and to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _nwith control n electric proportional variable pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

In this example, require that (traffic demand) obtains the target discharge capacity q of variable displacement pump group according to the current work of hydraulic system, controller calculates the target discharge capacity q of n variable displacement pump by optimizing algorithm ₁, q ₂..., q _n, wherein, q=q ₁+ q ₂+ ...+q _n, in variable displacement pump group, n variable displacement pump operates in target discharge capacity q ₁, q ₂..., q _nunder, under variable displacement pump group is operated in maximal efficiency.Like this, meeting the variable displacement pump group target discharge capacity q of hydraulic system current work requirement, obtain the target discharge capacity of variable displacement pump group n variable displacement pump under maximal efficiency, achieve the maximizing efficiency of variable displacement pump group by the control mode of n variable displacement pump in dynamic adjustments variable displacement pump group; Synchronous impartial control mode in prior art, reduces the phenomenon such as leakage and loss of variable displacement pump group, improve variable displacement pump group efficiency, and dynamic adjustments control mode improves the working life of variable displacement pump group.

In above-mentioned control procedure, as the discharge capacity q < q of variable displacement pump group _1max+ q _2max+ ...+q _nmaxnamely in variable displacement pump group, n variable displacement pump is not when operating at full capacity completely, in order to reduce the overall losses of variable displacement pump group, makes whole variable displacement pump group have longer working life, under the prerequisite meeting the requirement of operation horizontal stability, n variable displacement pump alternation in controlled variable pump group.

In a kind of embodiment, at q < q _1max+ q _2max+ ...+q _nmaxwhen, the alternation time T of design variables pump group, when described variable displacement pump group operation reaches alternation time T, controls n variable displacement pump alternation in described variable displacement pump group.

In another kind of embodiment, at q < q _1max+ q _2max+ ...+q _nmaxwhen, according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T, when described variable displacement pump group operation reaches alternation time T, control n variable displacement pump alternation in described variable displacement pump group.

Particularly, the life consumption threshold value Δ s of design variables pump _t, and, can according to the target discharge capacity q of the working pressure p of variable displacement pump group, operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nthe life consumption Δ s of n variable displacement pump is determined with t working time ₁, Δ s ₂..., Δ x _n,

Δs ₁＝G(p，r，q ₁，t)、Δs ₂＝G(p，r，q ₂，t)、…、Δs _n＝G(p，r，q _n，t)，

Wherein, life consumption threshold value Δ s _tcan determine according to parameters such as the running parameter of variable displacement pump, field working conditions condition, construction periods, working pressure p can adopt the pressure of hydraulic oil, and operating ambient temperature r can adopt the temperature of hydraulic oil; Like this, in the process determining alternation time T, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of variable displacement pump group is defined as alternation time T.

The invention allows for a kind of engineering machinery, comprise variable displacement pump group, also comprise the control system of any one variable displacement pump group above-mentioned.

Based on the technique effect of the control system of above-mentioned variable displacement pump group, the engineering machinery comprising the control system of this variable displacement pump group has above-mentioned technique effect too.

These are only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (11)

1. a controlling method for variable displacement pump group, described variable displacement pump group is formed in parallel by n variable displacement pump, and n >=2, is characterized in that, described controlling method comprises:

According to the target discharge capacity q of described variable displacement pump group, under predetermined working pressure p, build efficiency e and n variable pump delivery q of described variable displacement pump group ₁, q ₂..., q _nfunctional relation:

$\left\{\begin{array}{c}\max \left(e\right)=\max [f\left(q_1\right)\&times;f\left(q_2\right)\&times;...\&times;f\left(q_n\right)]\\ f\left(0\right)=1\\ q=q_1+q_2+...+q_n\\ 0\&le;q_1\&le;q_{1\max },0\&le;q_2\&le;q_{2\max },...,0\&le;q_n\&le;q_{n\max }\end{array}\right.$

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump; F (q ₁), f (q ₂) ..., f (q _n) be respectively the 1st, 2 ..., a n variable displacement pump efficiency and the corresponding the 1st, 2 ..., a n variable pump delivery function relation;

According to above-mentioned functional relation, calculated the target discharge capacity q of described variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and to control in described variable displacement pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

2. the controlling method of variable displacement pump group according to claim 1, is characterized in that, described variable displacement pump is electric proportional variable pump, according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, and to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _nwith control n electric proportional variable pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

3. the controlling method of variable displacement pump group according to claim 1 and 2, is characterized in that, at q < q _1max+ q _2max+ ...+q _nmaxwhen, the alternation time T of design variables pump group, or, according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T; When described variable displacement pump group operation reaches alternation time T, control n variable displacement pump alternation in described variable displacement pump group.

4. the controlling method of variable displacement pump group according to claim 3, is characterized in that, according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, the life consumption threshold value Δ s of design variables pump _t, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of described variable displacement pump group is defined as alternation time T.

5. the controlling method of variable displacement pump group according to claim 4, is characterized in that, according to the working pressure p of described variable displacement pump group, the target discharge capacity q of operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nwith t working time, determine the life consumption Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, wherein,

Δs ₁＝G(p,r,q ₁,t)、Δs ₂＝G(p,r,q ₂,t)、…、Δs _n＝G(p,r,q _n,t)。

6. a control system for variable displacement pump group, described variable displacement pump group is formed in parallel by n variable displacement pump, and n >=2, is characterized in that, described control system comprises controller, and controller is connected with n variable displacement pump in described variable displacement pump group;

According to the target discharge capacity q of described variable displacement pump group, under predetermined working pressure p, described controller builds efficiency e and n variable pump delivery q of described variable displacement pump group ₁, q ₂..., q _nfunctional relation:

$\left\{\begin{array}{c}\max \left(e\right)=\max [f\left(q_1\right)\&times;f\left(q_2\right)\&times;...\&times;f\left(q_n\right)]\\ f\left(0\right)=1\\ q=q_1+q_2+...+q_n\\ 0\&le;q_1\&le;q_{1\max },0\&le;q_2\&le;q_{2\max },...,0\&le;q_n\&le;q_{n\max }\end{array}\right.$

Wherein, q _1max, q _2max..., q _nmaxbe respectively the maximum pump discharge of n variable displacement pump; F (q ₁), f (q ₂) ..., f (q _n) be respectively the 1st, 2 ..., a n variable displacement pump efficiency and the corresponding the 1st, 2 ..., a n variable pump delivery function relation;

Described controller, according to above-mentioned functional relation, calculates the target discharge capacity q of described variable displacement pump group n variable displacement pump under maximal efficiency max (e) by optimizing algorithm ₁, q ₂..., q _n, and to control in described variable displacement pump group n variable displacement pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

7. the control system of variable displacement pump group according to claim 6, is characterized in that, described variable displacement pump is electric proportional variable pump, and described controller is according to the target discharge capacity q of n electric proportional variable pump ₁, q ₂..., q _ncalculate corresponding proportional current i ₁, i ₂..., i _n, and to n electric proportional variable pump export ratio current i respectively ₁, i ₂..., i _nwith control n electric proportional variable pump at target discharge capacity q ₁, q ₂..., q _nlower operation.

8. the control system of the variable displacement pump group according to claim 6 or 7, is characterized in that, at q<q _1max+ q _2max+ ...+q _nmaxwhen, the alternation time T of design variables pump group in the controller, or described controller is according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _ndetermine alternation time T; When described variable displacement pump group operation reaches alternation time T, described controller can control n variable displacement pump alternation in described variable displacement pump group.

9. the control system of variable displacement pump group according to claim 8, is characterized in that, described controller is according to the life consumption value Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, the life consumption threshold value Δ s of design variables pump _t, at Δ s ₁, Δ s ₂..., Δ s _nin arbitrary life consumption value reach default life consumption threshold value Δ s _ttime, the current run time t of described variable displacement pump group is defined as alternation time T by described controller.

10. the control system of variable displacement pump group according to claim 9, is characterized in that, the working pressure p of described controller according to described variable displacement pump group, the target discharge capacity q of operating ambient temperature r, n variable displacement pump ₁, q ₂..., q _nwith t working time, determine the life consumption Δ s of n variable displacement pump ₁, Δ s ₂..., Δ s _n, wherein,

Δs ₁＝G(p,r,q ₁,t)、Δs ₂＝G(p,r,q ₂,t)、…、Δs _n＝G(p,r,q _n,t)。

11. 1 kinds of engineering machinery, comprise variable displacement pump group, it is characterized in that, also comprise the control system of the variable displacement pump group described in any one of claim 6 to 10.