CN105201935B - A kind of variable speed hydraulic power supply flow control system and method - Google Patents

Abstract

The invention discloses a kind of variable speed hydraulic power supply flow control system and method, including subtractor, PID controller, adder, servo-driver, magneto, gear pump, motor, current feed-forward device, for detecting the Hall current sensor of permanent magnet motor stator side electric current and for detecting the flow transducer of gear pump oil-out flow information.The present invention is capable of the flow-control of variable speed hydraulic power supply, and fast response time, and precision is higher.

Description

A kind of variable speed hydraulic power supply flow control system and method

Technical field

The invention belongs to hydraulic power system and control technical field, relate to a kind of variable speed hydraulic power Source flux control system and method.

Background technology

Hydraulic drive and control technology be collection hydraulic technique, microelectric technique, sensing detection technology, Numerous subjects such as computer control and modern control theory are comprehensive in high intercrossing, the height of one Technology-oriented discipline, has significant mechanical-electrical-hydraulic integration feature.In hydraulic test, major part will be to execution The speed of mechanism is controlled, say, that speed regulating control is the core of hydraulic test, is generally divided into Throttle grverning and two kinds of valve control forms of volumetric speed control.Continuous along with frequency conversion speed-adjusting Universal, hydraulic test variable frequency volume speed governing (variable speed control) method is suggested, its principle be by Quantitative oil pump and motor AC speed adjusting technique organically combine, and realize flow by the change of pump speed Dynamic regulation, eliminate the change displacement control mechanism of complexity compared with variable pump systems.With biography System valve controlled velocity modulation system is compared variable speed fluid speed regulating control and is simplified hydraulic circuit, contamination resistance By force, the energy loss of hydraulic valve is reduced or completely eliminated, has improve system effectiveness and reliability, Efficiency is up to more than 80%, and simple in construction, dynamic property are good, therefore hydraulic test variable speed Control to become Chinese scholars research and development focus.

The Speed rigidity of Reduction in Variable-speed Pump-control-motor System governing system is relatively low, and the effect of load torque can make Hydraulic pump, hydraulic motor and control valve produce leakage, cause motor rotary speed landing occur；Load turns The effect of square is also due to the mechanical property of motor produces certain motor speed loss；Hydraulic oil has can Compressibility, when system pressure changes, hydraulic oil volume can change；Load torque is more Greatly, motor speed loss is the most obvious.Therefore, how Active Compensation loads the motor rotary speed caused Landing is to ensure that the key point of adjusting speed accuracy.

High-power big inertia Pump-control-motor Speed Governing System with Inverter Based adds system due to the existence of big inertia Stability, but reduce system response rapidity, the most how to improve this kind of system response Rapidity is to improve another key issue of real-time tracking effect.High-power big inertia variable frequency pump control Motor governing system is due to the regulation dead band of big rotary inertia and hydraulic system so that control system There is bigger time lag, control system low-response, dynamic and static performance is the most poor, and permanent PID is anti- Feedback control method is difficult to obtain satisfied control effect.Such as: during loading, system pressure increases, Oil liquid leakage amount increases, so flow system flow there will be of short duration minimizing, can affect the control essence of speed Degree.Existing flow system flow hardware compensating measure all has certain limitation, such as: become in load Suitably adjust the rotating speed of pump (motor) during change, can appropriateness compensate loop leakage flow, maintain The stability of executor's rotating speed, but the amount compensated lacks theoretical direction, easily causes overcompensation or owes Compensate；It addition, select the converter of band vector controlled can improve motor speed axle largely Speed stiffness, be conducive to improving adjusting speed accuracy, vector type converter can not reduce hydraulic system The impact that system is exported of slow time-varying characteristic.

Summary of the invention

It is an object of the invention to the shortcoming overcoming above-mentioned prior art, it is provided that a kind of variable speed liquid Pressure power source flux control system and method, this system and method is capable of variable speed hydraulic power The flow-control in source, and fast response time, precision is higher,

For reaching above-mentioned purpose, variable speed hydraulic power supply flow control system bag of the present invention Include subtractor, PID controller, adder, servo-driver, magneto, gear pump, horse Reach, current feed-forward device, for detect permanent magnet motor stator side electric current Hall current sensor, And for detecting the flow transducer of gear pump oil-out flow information；

The outfan of described servo-driver is connected with the control end of magneto, magneto Output shaft is connected with the drive shaft of gear pump, and the oil-out of fuel tank is connected with the oiler of gear pump Logical, the oil-out of gear pump is connected with the oiler of motor, and the oil-out of motor enters with fuel tank Hydraulic fluid port is connected, and the outfan of Hall current sensor is connected with the input of current feed-forward device Connecing, the outfan of current feed-forward device is connected with the input of adder, flow transducer defeated Go out end to be connected with the input of subtractor, the outfan of subtractor and the input of PID controller Being connected, the outfan of PID controller is connected with the input of adder, the output of adder End is connected with the input of servo-driver.

Variable speed hydraulic power supply flow control methods of the present invention comprises the following steps:

1) the flow information Q at flow transducer Real-time Collection gear pump oil-out_p, and by gear Pump out the flow information Q of oil port_pBeing forwarded in subtractor, subtractor passes through goal-selling flow value Q_rDeduct current gear and pump out the flow value Q of oil port_pObtain flow system flow deviation, and by described system Flow deviation is forwarded in PID controller, and PID controller produces according to described flow system flow deviation PID controlled quentity controlled variable, and described PID controlled quentity controlled variable is forwarded in adder；Hall current sensor Detect the current information of permanent magnet motor stator side in real time, and by the electric current of described permanent magnet motor stator side Information is forwarded to current feed-forward device, and current feed-forward device is fixed according to presently described magneto The current information of sub-side produces control information, and described control information is forwarded in adder, adds Described control information and PID controlled quentity controlled variable are carried out additive operation by musical instruments used in a Buddhist or Taoist mass, and by the result of additive operation It is forwarded in servo-driver；

2) servo-driver is according to step 1) the output control magneto work of sum operation that obtains Making, the output shaft driven gear pump work of magneto, gear pump output hydraulic pressure oil drives motor work Make.

When the current information of the permanent magnet motor stator side that current feed-forward device receives is not changed in Time, then the control information exported is " 0 "；The magneto received when current feed-forward device is fixed When the current information of sub-side changes, then according to the change of the current information of permanent magnet motor stator side Amount produces control information.

Torque balance equation in the drive shaft of gear pump is:

$T_L=J_p\frac{d\mathrm{\ω}}{dt}+B_p\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p---\left(1\right)$

Wherein, T_LFor the input torque of gear pump,For the inertia torque of gear pump, B_pω is gear The damping torque of pump,The torque produced for oil liquid pressure, J_pFor the rotary inertia of gear pump, B_pDamped coefficient for gear pump；

Torque balance equation in the drive shaft of magneto is:

$J_m\frac{d\mathrm{\ω}}{dt}+B_m\mathrm{\ω}+T_L=T_e---\left(2\right)$

Wherein,For the inertia torque of magneto, B_mω is the drag torque of magneto, T_LFor The load torque of magneto, T_eFor the electromagnetic torque of magneto, J_mRotation for magneto Inertia, B_mDamped coefficient for magneto；

Electromagnetic torque T_eExpression formula be:

$T_e=\frac{3p}{2}{K}_{e}i---\left(3\right)$

Wherein, p is the number of pole-pairs of magneto, and i is the stator side electric current of magneto, K_eFor Permanent Magnet and Electric The back emf coefficient of machine；

Formula (1) and formula (3) are substituted in (2) formula,

$(J_p+J_m)\frac{d\mathrm{\ω}}{dt}+(B_p+B_m)\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p=\frac{3p}{2}{K}_{e}i---\left(4\right)$

Obtained by formula (4), the output pressure P of gear pump_pRotational speed omega and magneto with magneto Two variablees of electric current i relevant.

The method have the advantages that

Variable speed hydraulic power supply flow control system of the present invention and method are operationally, logical Flow information at inflow-rate of water turbine sensor acquisition gear pump oil-out, and by described gear pump oil-out Place flow information subtract each other with target flow, obtain flow system flow deviation, PID controller according to The deviation of flow system flow provides PID controlled quentity controlled variable, and PID controlled quentity controlled variable is input in adder, electricity Stream feedforward controller judges running situation according to the current information of current permanent magnet motor stator side, Then obtain control information according to running situation, and described control information is forwarded to adder In, servo-driver works according to the output control magneto of adder additive operation, Permanent Magnet and Electric Machine drives motor operations by gear pump, it is achieved to the control of hydraulic fluid flow rate at gear pump oil-out, Thus realize the control to variable speed hydraulic power source flux.Present invention firstly provides current feed-forward, Flow feedback combines, and forms the combined compensation active control strategies of current feed-forward-feedback, thus logical The overcurrent feedforward solves hydraulic system owing to occurring flow system flow transient wave when load disturbance changes Dynamic big, response speed slow, is difficult to the problems such as adjustment, combine with PID controller elimination liquid simultaneously The steady-state error of pressure power source flux, improves control accuracy.

Accompanying drawing explanation

Fig. 1 is the structural representation of the present invention；

Fig. 2 is magneto 5 stator side electric current and system pressure graph of a relation in the present invention；

Current-to-pressure graph of a relation when Fig. 3 is to survey hydraulic system loading, off-load in the present invention；

Fig. 4 is that traditional actual measurement PID method flow step loads response diagram；

Fig. 5 is that the flow step of the present invention loads response diagram；

Fig. 6 is that traditional actual measurement PID control method flow slope loads response diagram；

Fig. 7 is that the flow slope of the present invention loads response diagram；

Wherein, 1 be subtractor, 2 for PID controller, 3 for adder, 4 for servo-driver, 5 be magneto, 6 be gear pump, 7 be motor, 8 be current feed-forward device, 9 for Hall Current sensor, 10 it is flow transducer.

Detailed description of the invention

Below in conjunction with the accompanying drawings the present invention is described in further detail:

With reference to Fig. 1, variable speed hydraulic power supply flow control system of the present invention includes subtraction Device 1, PID controller 2, adder 3, servo-driver 4, magneto 5, gear pump 6, Motor 7, current feed-forward device 8, for detecting the Hall current of magneto 5 stator side electric current Sensor 9 and for detecting the flow transducer 10 of gear pump 6 oil-out flow information；Institute The control end of the outfan and magneto 5 of stating servo-driver 4 is connected, magneto 5 Output shaft is connected with the drive shaft of gear pump 6, the oil-out of fuel tank and the oiler of gear pump 6 Being connected, the oil-out of gear pump 6 is connected with the oiler of motor 7, the oil-out of motor 7 It is connected with the oiler of fuel tank, the outfan of Hall current sensor 9 and current feed-forward device The input of 8 is connected, and the outfan of current feed-forward device 8 connects with the input of adder 3 Connecing, the outfan of flow transducer 10 is connected with the input of subtractor 1, subtractor 1 defeated Go out end to be connected with the input of PID controller 2, the outfan of PID controller 2 and adder The input of 3 is connected, and the outfan of adder 3 is connected with the input of servo-driver 4.

Variable speed hydraulic power supply flow control methods of the present invention comprises the following steps:

1) the flow information Q at flow transducer 10 Real-time Collection gear pump 6 oil-out_p, and will Flow information Q at gear pump 6 oil-out_pBeing forwarded in subtractor 1, subtractor 1 is by presetting Target flow value Q_rDeduct the flow value Q at current gear pump 6 oil-out_pObtain flow system flow deviation, And described flow system flow deviation is forwarded in PID controller 2, PID controller 2 is according to described Flow system flow deviation produces PID controlled quentity controlled variable, and described PID controlled quentity controlled variable is forwarded to adder 3 In；Hall current sensor 9 detects the current information of magneto 5 stator side in real time, and by institute The current information stating magneto 5 stator side is forwarded to current feed-forward device 8, current feed-forward control Device 8 processed produces control information according to the current information of presently described magneto 5 stator side, and will Described control information is forwarded in adder 3, and described control information is controlled by adder 3 with PID Amount carries out additive operation, and the result of additive operation is forwarded in servo-driver 4；

2) servo-driver 4 is according to step 1) the output control magneto of sum operation that obtains 5 work, the output shaft driven gear pump 6 of magneto 5 works, gear pump 6 output hydraulic pressure oil Motor 7 is driven to work.

It should be noted that magneto 5 stator side received when current feed-forward device 8 When current information is not changed in, then the control information exported is " 0 "；When current feed-forward device 8 When the current information of magneto 5 stator side received changes, then according to magneto 5 The variable quantity of the current information of stator side produces control information.

Torque balance equation in the drive shaft of gear pump 6 is:

$T_L=J_p\frac{d\mathrm{\ω}}{dt}+B_p\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p---\left(1\right)$

Wherein, T_LFor the input torque of gear pump 6,For the inertia torque of gear pump 6, B_pω is The damping torque of gear pump 6,The torque produced for oil liquid pressure, J_pTurning for gear pump 6 Dynamic inertia, B_pDamped coefficient for gear pump 6；

Torque balance equation in the drive shaft of magneto 5 is:

$J_m\frac{d\mathrm{\ω}}{dt}+B_m\mathrm{\ω}+T_L=T_e---\left(2\right)$

Wherein,For the inertia torque of magneto 5, B_mω is the drag torque of magneto 5, T_LFor the load torque of magneto 5, T_eFor the electromagnetic torque of magneto 5, J_mFor Permanent Magnet and Electric The rotary inertia of machine 5, B_mDamped coefficient for magneto 5；

Electromagnetic torque T_eExpression formula be:

$T_e=\frac{3p}{2}{K}_{e}i---\left(3\right)$

Wherein, p is the number of pole-pairs of magneto 5, and i is the stator side electric current of magneto 5, K_eFor forever The back emf coefficient of magneto 5；

Formula (1) and formula (3) are substituted in (2) formula,

$(J_p+J_m)\frac{d\mathrm{\ω}}{dt}+(B_p+B_m)\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p=\frac{3p}{2}{K}_{e}i---\left(4\right)$

Obtained by formula (4), the output pressure P of gear pump 6_pRotational speed omega and permanent magnetism with magneto 5 Two variablees of the electric current i of motor 5 are relevant, it can be deduced that under different rotating speeds motor stator side electric current be Relation between system pressure, as shown in Figure 2.

As can be seen from Figure 3, when hydraulic system load is suddenlyd change, the change of magneto 5 stator side electric current It is Tong Bu that change almost changes with system pressure, therefore with magneto 5 stator side electric current as front Feedback signal is feasible.

As shown in Figure 4, after flow system flow is stable, add step rising, step with proportional pressure control valve Declining load, system pressure rises to 5MPa, and temperature is 23.5 DEG C；When system pressure step rises, Owing to the leakage rate of gear pump 6 increases, flow is caused to reduce, but owing to system uses stream Amount closed loop control, it is possible to compensate gear pump 6 by controlling the increase of magneto 5 rotating speed The increase of leakage, flow system flow is stable through 6.5 seconds adjustment and recoveries, reaches the target flow set. Meanwhile, when system pressure step decrease, flow can rise, regulate Permanent Magnet and Electric by closed loop control Machine 5 rotating speed, makes flow system flow reach the desired value set.

As shown in Figure 5, after adding current feed-forward, during load change, by the change of system pressure Change the change being coupled to current of electric, the variable quantity of current value is defeated through current feed-forward device 8 Being added with PID controlled quentity controlled variable after going out, now the simulation input controlled quentity controlled variable of magneto 5 increases, permanent magnetism The rotating speed of motor 5 raises, and the output flow of hydraulic power supply increases, target flow and flow system flow Deviation quickly diminishes, and the adjustment time of the present invention is only 2 seconds, controls to adjust than traditional PID/feedback The whole time shortens 4.5 seconds.

It will be appreciated from fig. 6 that after flow system flow is stable, adds with proportional pressure control valve and ramp up, under slope Load shedding lotus, system pressure rises to 5MPa, and temperature is 23.5 DEG C, system pressure when adding slope load Compare step load to rise slowly, but the adjustment time of flow remains as 6.5 seconds.

As shown in Figure 7, add after current feed-forward, when slope loads during the adjustment of flow system flow Between be 2.5 seconds, control the adjustment time than traditional PID/feedback and shorten 4 seconds.

Thus, the present invention efficiently solves variable speed hydraulic power supply and occurs when load disturbance changes The fluctuation of system instantaneous delivery is big, response speed slow, is difficult to the problems such as adjustment, in conjunction with the feedforward and The advantage of feedback control, it is achieved that variable speed hydraulic power supply based on current feed-forward actively controls.

Claims (2)

1. a variable speed hydraulic power supply flow control methods, it is characterised in that based on variable speed Hydraulic power supply flow control system, described variable speed hydraulic power supply flow control system includes subtraction Device (1), PID controller (2), adder (3), servo-driver (4), magneto (5), Gear pump (6), motor (7), current feed-forward device (8), it is used for detecting magneto (5) The Hall current sensor (9) of stator side electric current and be used for detecting gear pump (6) oil-out stream The flow transducer (10) of amount information；

The outfan of described servo-driver (4) is connected, forever with the control end of magneto (5) The output shaft of magneto (5) is connected with the drive shaft of gear pump (6), the oil-out of fuel tank and tooth The oiler of wheel pump (6) is connected, the oil-out of gear pump (6) and the oiler of motor (7) Being connected, the oil-out of motor (7) is connected with the oiler of fuel tank, Hall current sensor (9) Outfan be connected with the input of current feed-forward device (8), current feed-forward device (8) Outfan be connected with the input of adder (3), the outfan of flow transducer (10) with subtract The input of musical instruments used in a Buddhist or Taoist mass (1) is connected, the outfan of subtractor (1) and PID controller (2) Input is connected, and the outfan of PID controller (2) is connected with the input of adder (3), The outfan of adder (3) is connected with the input of servo-driver (4)；

Comprise the following steps:

1) the flow information Q at flow transducer (10) Real-time Collection gear pump (6) oil-out_p, And by the flow information Q at gear pump (6) oil-out_pIt is forwarded in subtractor (1), subtractor (1) By goal-selling flow value Q_rDeduct the flow value Q at current gear pump (6) oil-out_pThe system of obtaining Flow deviation, and described flow system flow deviation is forwarded in PID controller (2), PID controls Device (2) produces PID controlled quentity controlled variable according to described flow system flow deviation, and by described PID controlled quentity controlled variable It is forwarded in adder (3)；It is fixed that Hall current sensor (9) detects magneto (5) in real time The current information of sub-side, and the current information of described magneto (5) stator side is forwarded to electric current Feedforward controller (8), current feed-forward device (8) is according to presently described magneto (5) stator The current information of side produces control information, and described control information is forwarded in adder (3), Described control information and PID controlled quentity controlled variable are carried out additive operation by adder (3), and by additive operation Result be forwarded in servo-driver (4)；

2) servo-driver (4) is according to step 1) the output control Permanent Magnet and Electric of sum operation that obtains Machine (5) works, output shaft driven gear pump (6) work of magneto (5), gear pump (6) Output hydraulic pressure oil drives motor (7) work；

The current information of magneto (5) stator side received when current feed-forward device (8) does not has When changing, then the control information exported is " 0 "；When current feed-forward device (8) receives When the current information of magneto (5) stator side changes, then according to magneto (5) stator The variable quantity of the current information of side produces control information.

Variable speed hydraulic power supply flow control methods the most according to claim 1, its feature It is,

Torque balance equation in the drive shaft of gear pump (6) is:

$T_L=J_p\frac{d\mathrm{\ω}}{dt}+B_p\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p---\left(1\right)$

Wherein, T_LFor the input torque of gear pump (6),For the inertia torque of gear pump (6), B_pω For the damping torque of gear pump (6),The torque produced for oil liquid pressure, J_pFor gear pump (6) Rotary inertia, B_pDamped coefficient for gear pump (6)；

Torque balance equation in the drive shaft of magneto (5) is:

$J_m\frac{d\mathrm{\ω}}{dt}+B_m\mathrm{\ω}+T_L=T_e---\left(2\right)$

Wherein,For the inertia torque of magneto (5), B_mω is the resistance of magneto (5) Torque, T_LFor the load torque of magneto (5), T_eFor the electromagnetic torque of magneto (5), J_m For the rotary inertia of magneto (5), B_mDamped coefficient for magneto (5)；

Electromagnetic torque T_eExpression formula be:

$T_e=\frac{3p}{2}{K}_{e}i---\left(3\right)$

Wherein, p is the number of pole-pairs of magneto (5), and i is the stator side electric current of magneto (5), K_e Back emf coefficient for magneto (5)；

Formula (1) and formula (3) are substituted in (2) formula,

$(J_p+J_m)\frac{d\mathrm{\ω}}{dt}+(B_p+B_m)\mathrm{\ω}+\frac{D_p}{2\mathrm{\π}}{P}_p=\frac{3p}{2}{K}_{e}i---\left(4\right)$

Obtained by formula (4), the output pressure P of gear pump (6)_pWith the rotational speed omega of magneto (5) and Two variablees of the electric current i of magneto (5) are relevant.