KR101095983B1 - Hydraulic transmission system and method for controlling thereof - Google Patents

Abstract

PURPOSE: A hydrostatic transmission system and a control method thereof are provided to improve energy efficiency by variously controlling a hydraulic pump and a hydraulic motor during static operation. CONSTITUTION: A hydrostatic transmission system comprises a hydraulic pump(120), a hydraulic motor(130), a pressure sensor(122), a current sensor(132), and a hydraulic control unit(140). The hydraulic pump variably controls the pressure of the fluid, provided to an actuator(110). The hydraulic motor provides the power source and changeably drives the hydraulic pump. The pressure sensor measures a discharge pressure of the hydraulic pump. The current sensor measures on the current supplied to the hydraulic motor. The hydraulic control unit supplies the power source to the hydraulic motor. The hydraulic control unit receives the discharge pressure, measured by the pressure sensor, and the current, measured by the current sensor, in order to variably control the speed of rotation of the hydraulic motor.

Description

HYDRAULIC TRANSMISSION SYSTEM AND METHOD FOR CONTROLLING THEREOF

The present invention relates to a hydraulic transmission system, and more particularly, to a hydraulic transmission system for controlling a hydraulic motor and a hydraulic pump by reducing power consumption and a control method thereof.

The present invention also relates to a hydraulic transmission system and a control method thereof, which regenerate back electromotive force generated when the rotational speed of the hydraulic motor decreases to an electromotive force and resupply the driving power of the hydraulic motor.

In addition, the present invention relates to a hydraulic power transmission system and a control method thereof which reduce energy according to optimum operation, reduce carbon dioxide (CO2) emission, lower hydraulic oil temperature, and are easy to install, operate, and maintain.

In general, the hydraulic pump is mechanically connected to the hydraulic motor so that the piston of the hydraulic pump reciprocates by the rotational movement of the hydraulic motor.

The hydraulic pump is a device for discharging fluid while reciprocating several pistons by this reciprocating motion. The hydraulic pump is thus supplied with fluid to the wheel cylinder at the required time at the actuator.

1 is a block diagram schematically showing the structure of a conventional hydraulic transmission system, Figure 2 is a graph showing the power consumption used according to the time of the conventional hydraulic transmission system.

Such a conventional hydraulic transmission system 10 includes a hydraulic reservoir 1, a hydraulic pump 2, an actuator 3, and a hydraulic motor 4, as shown in FIG.

The hydraulic reservoir 1 stores hydraulic flow. The hydraulic pump 2 has a hydraulic reservoir 1 connected to the suction side, and an actuator 3 connected to the discharge side. The hydraulic pump 2 pumps hydraulic flow from the hydraulic reservoir 1 to increase the pressure at the actuator 3, and the hydraulic motor 4 is connected to the hydraulic pump 2 to drive the hydraulic pump 2. Connected. For example, the hydraulic motor 4 is provided with a three-phase induction motor, and the hydraulic pump 2 is provided with a variable pump. In addition, the hydraulic transmission system 10 may further include a hydraulic motor driving unit (not shown) and a pressure sensor (not shown) for driving the hydraulic motor 4.

Since the hydraulic transmission system 10 is driven to maintain the hydraulic motor 4 at a constant speed regardless of the load at all times, a lot of driving noise is generated in the hydraulic pump 2 and the hydraulic motor 4. In the hydraulic transmission system 10, the hydraulic motor 4 always operates at a constant speed regardless of the increase or decrease of the hydraulic pressure in the hydraulic pump 2, so that even if the hydraulic pressure decreases, the power consumed by the hydraulic motor 4 is almost unchanged. none. As a result, the hydraulic power transmission system 10 generates a lot of unnecessary power consumption, thereby causing a large amount of carbon dioxide (CO2) emissions.

In addition, in the conventional hydraulic transmission system 10, the hydraulic motor driving unit is provided as an inverter, and the rotation speed of the hydraulic motor 4 can be variably driven by measuring the hydraulic pressure of the actuator by a hydraulic sensor (not shown).

In this case, when hydraulic pressure is required in the actuator 3, the hydraulic motor 4 rotates at high speed, and when the hydraulic pressure is holding pressure, the hydraulic motor 4 is driven at a low speed state in which no load is applied to the hydraulic motor 4. At this time, the counter electromotive force is generated in the hydraulic motor 4. Since the counter electromotive force causes a waste of power, it is necessary to regenerate power using the counter electromotive force.

That is, in the conventional hydraulic transmission system 10, as shown in FIG. 2, the average power consumption is about 843 W, and the counter electromotive force generated when the rotation speed of the hydraulic motor 4 is reduced in the system using the inverter is hydraulic. When used for rotational drive of the motor 4, the method is applied to convert it into thermal energy using a resistor (not shown) separately installed and then consume it as it is. Therefore, there is a problem that energy is wasted in terms of energy efficiency. .

SUMMARY OF THE INVENTION An object of the present invention devised in view of the above is to provide a hydraulic transmission system having a hydraulic control unit for controlling a hydraulic motor and a hydraulic pump, and a control method thereof.

Another object of the present invention is to provide an eco-friendly hydraulic transmission system and a control method thereof, which reduce power consumption, have low heat generation and low noise, and are easy to operate and maintain.

It is another object of the present invention to provide a hydraulic transmission system and a control method for regenerating back electromotive force generated by the electromotive force generated by the reduction in the number of rotation of the hydraulic motor used in the hydraulic transmission system to reuse the power.

In addition, the present invention is to provide a hydraulic transmission system and a control method thereof, while preventing damage to the drive circuit for the hydraulic control and at the same time increase the compatibility of the hydraulic control unit, easy installation, operation and maintenance.

Hydraulic transmission system for achieving the object of the present invention as described above, and a hydraulic pump for variably adjusting the pressure of the fluid supplied to the actuator; A hydraulic motor for variably driving the hydraulic pump by receiving power; A pressure sensor for measuring a discharge pressure of the hydraulic pump; A current sensor for measuring a supply current to the hydraulic motor; And a hydraulic control unit for supplying the power to the hydraulic motor, receiving the discharge pressure measured from the pressure sensor, and variably controlling the rotational speed of the hydraulic motor by receiving the supply current measured from the current sensor. .

The hydraulic control unit is provided on one printed circuit board and modularized. Wherein the hydraulic control unit; A power supply unit for supplying power; Accepts the discharge pressure measured from the pressure sensor, receives the supply current measured from the current sensor and variably controls the rotation speed of the hydraulic motor, and determines whether the rotation speed of the hydraulic motor is decelerated from the current sensor. A controller for detecting; Receiving power from the power supply unit and supplying power to the hydraulic motor, and when the rotational speed of the hydraulic motor is decelerated from the controller, receives the counter electromotive force generated by the deceleration of the rotational speed to reproduce the electromotive force to the power of the hydraulic motor And an inverter control unit for resupply.

The inverter control unit; An inverter for receiving direct current or alternating current power from the power supply and supplying direct current power to the hydraulic motor; And a power regenerative unit configured to receive the counter electromotive force from the inverter and regenerate the electromotive force to supply the inverter to the inverter under the control of the controller.

In addition, the inverter control unit; An AC reactor which receives AC power from the power supply and smoothes current and removes noise to supply the inverter to the inverter; It is further provided with a DC reactor installed in the inverter to smooth the DC power of the inverter or remove noise.

The power regenerative unit; It is composed of a bridge circuit having a plurality of switching elements between the wiring connected to the inverter. Here, the switching elements are switched by the controller to output the counter electromotive force of the DC power supply to the electromotive force of the AC power supply to the inverter.

The hydraulic pump may be a variable piston pump or a variable vane pump.

The hydraulic transmission system; If an abnormality occurs in the detection signal for the discharge pressure and the supply current measured from the pressure sensor and the current sensor, an alarm unit for generating an alarm sound to the outside.

According to another aspect of the present invention, there is provided a control method of a hydraulic transmission system, including: driving a hydraulic motor by supplying power; Measuring a supply current supplied to the hydraulic motor; Pumping fluid into an actuator by driving a hydraulic pump by the hydraulic motor; Measuring a rotational speed of the hydraulic motor by measuring a discharge pressure discharged from the hydraulic pump; And variably controlling the hydraulic motor in response to the measured discharge pressure and the rotational speed.

The method; Receiving the counter electromotive force from the hydraulic motor and reproducing the electromotive force when the measured rotation speed is reduced; Resupplying the electromotive force to the power of the hydraulic motor.

Driving the hydraulic motor; It receives AC power and converts it into DC power to supply DC power to the hydraulic motor. The regeneration may be performed by receiving the counter electromotive force of the DC power and regenerating the electromotive force of the AC power.

The method also includes; If an abnormality occurs in the hydraulic transmission system, further comprising the step of generating an alarm sound.

As described above, the hydraulic transmission system of the present invention includes a hydraulic control unit that variably controls the hydraulic motor and the hydraulic pump in response to the load of the actuator, thereby reducing power consumption and improving energy efficiency. CO2 emissions can be reduced. In particular, in the case of holding pressure, by controlling in consideration of the efficiency characteristics of the hydraulic pump and the hydraulic motor, it is possible to operate in the optimum conditions.

In addition, the hydraulic transmission system of the present invention includes a power regenerative unit in the hydraulic control unit, whereby the counter electromotive force generated when the number of rotations of the motor used in the hydraulic transmission system decreases is regenerated by electromotive force using the power regenerative unit, and the power consumption is reduced. You can save about 40%.

In addition, the hydraulic transmission system of the present invention is implemented by modularizing the hydraulic control unit on a single printed circuit board, it is possible to miniaturize, increase the compatibility for a variety of hydraulic transmission system and can be easily installed and used.

1 is a block diagram schematically showing the structure of a conventional hydraulic transmission system,
2 is a graph showing the power consumption used according to the time of the conventional hydraulic transmission system,
3 is a block diagram schematically illustrating a structure of a hydraulic transmission system having a hydraulic control unit according to an embodiment of the present invention.
4 is a circuit diagram showing a part of the configuration of the hydraulic control unit shown in FIG.
5 is a cross-sectional view showing the structure of a variable piston pump used in a hydraulic transmission system according to an embodiment of the present invention,
Figure 6 is a cross-sectional view showing the structure of a variable vane pump used in the hydraulic transmission system according to another embodiment of the present invention,
7 is a graph showing power consumption used according to time of the hydraulic transmission system according to an embodiment of the present invention,
8 and 9 are flowcharts illustrating a procedure of driving the hydraulic power transmission system according to an embodiment of the present invention.

The embodiments of the present invention can be modified into various forms and the scope of the present invention should not be interpreted as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and the like of the components in the drawings are exaggerated in order to emphasize a clearer explanation.

Hereinafter, a hydraulic transmission system and a control method thereof according to an embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

3 is a block diagram showing the configuration of a hydraulic transmission system according to an embodiment of the present invention, Figure 4 is a circuit diagram showing a part of the configuration of the hydraulic control unit shown in FIG.

First, referring to FIG. 3, the hydraulic transmission system 100 according to an embodiment of the present invention uses the inverter 170 to control the hydraulic control unit 140 for controlling the hydraulic pump 120 and the hydraulic motor 130. Equipped. The hydraulic transmission system 100 is energy-saving, environmentally friendly, low noise, low heat, easy to operate and maintain. Therefore, the hydraulic transmission system 100 of the present invention is applicable to machine tool equipment, such as ATC (Auto Tool Changer), APC (Auto Plate Changer) or NC lathe, for example, using the hydraulic pressure of the machine center, in particular It is effective for the equipment with long waiting time to keep the oil pressure constant.

To this end, the hydraulic transmission system 100 includes an actuator 110 in which fluid is pumped inside, a hydraulic pump 120 for variably adjusting the pressure of the fluid supplied to the actuator 110, and a hydraulic control unit. A hydraulic motor 130 that variably drives the hydraulic pump 120 by receiving power from the 140, and a hydraulic motor 130 that calculates a fluid discharge amount discharged by the hydraulic pump 120 and corresponds to the calculated discharge amount. Measures the rotational speed of, and using the measured rotational speed of the hydraulic motor 130 is provided with a hydraulic control unit 140 for variable control of the hydraulic motor 130 in real time. Here, the hydraulic pump 120 may be provided as a variable displacement pump or the like, and the hydraulic motor 130 may be provided as a variable speed hydraulic pump.

In addition, the hydraulic transmission system 100 includes a pressure sensor 122 for measuring a fluid discharge amount of the hydraulic pump 120, for example, a discharge pressure, and a current sensor for measuring a supply current supplied to the hydraulic motor 130 ( 132 is provided. In addition, the hydraulic transmission system 100 further includes an alarm unit 190 generating an alarm to the outside in response to the current operation state and the abnormality of the hydraulic pump 120, the hydraulic motor 130 and the like.

The hydraulic control unit 140 includes a controller 142 for controlling all operations of the hydraulic transmission system 100, a power supply unit 150 for supplying power under the control of the controller 142, and a power supply unit 150. Receiving power and supplying to the hydraulic motor 130, if the reverse electromotive force due to the deceleration from the hydraulic motor 130, the inverter control unit 144 for regenerating back electromotive force to the electromotive force to supply the power of the hydraulic motor 130 again; do.

The hydraulic control unit 140 mounts the controller 142, the power supply unit 150, and the inverter control unit 144 on a single printed circuit board (PCB) to provide a module, thereby providing a hydraulic control unit 140 It is possible to miniaturize, which makes it easy to reduce manufacturing costs and maintain.

That is, the hydraulic control unit 140 adjusts the rotational speed (rotational speed) of the hydraulic motor 130 and the pump capacity of the hydraulic pump 120 in response to the load situation of the actuator 110 to consume power (W). Can reduce the pressure and temperature of the fluid.

The power consumption of the hydraulic control unit 140 is shown in Equation 1 below.

Where W is electric power, N is the rotational speed (min ^-1 ) of the variable speed flow motor, q is the pump capacity (cm ³ / rev) of the hydraulic pump, P is the discharge pressure and η is the efficiency.

Therefore, the hydraulic control unit 140 uses the inverter controller 144 to variably control and drive the hydraulic motor 130 and the hydraulic pump 120. In particular, the hydraulic control unit 140 in accordance with the efficiency characteristics of the hydraulic pump 120 and the hydraulic motor 130 at the time of holding pressure, the variable driving power of the hydraulic pump 120 and the hydraulic motor 130 in the optimal driving conditions and power Minimize consumption

Specifically, the controller 142 controls the overall operation of the hydraulic transmission system 100. That is, the controller 142 is electrically connected to the pressure sensor 122 and the current sensor 132 to monitor the discharge pressure and the supply current, and receive the discharge pressure measured from the pressure sensor 122 of the hydraulic motor 130. The power regenerative unit of the inverter controller 144 controls the rotational speed variably, detects the rotational speed of the hydraulic motor 130 from the current sensor 132, and regenerates the electromotive force when counter electromotive force is generated in the hydraulic motor 130. 180). In addition, the controller 142 is electrically connected to the alarm unit 190, and when an abnormal occurrence and detection signal for the discharge pressure and the supply current detected by the pressure sensor 122 and the current sensor 132 are not received, Alarm sound.

The power supply unit 150 supplies DC or AC power to the inverter control unit 144. That is, the power supply unit 150 supplies at least one of DC and AC power to the inverter 170 of the inverter controller 144.

When the power supplied from the power supply unit 150 is AC power, the inverter controller 144 automatically cuts off an abnormal current such as an overcurrent or a short circuit current generated from a three-phase AC power supplied for circuit protection. Mold Case Current Braker (MCCB) 160, an AC reactor 162 that receives a three-phase AC power and smoothes current uniformly and removes noise, and receives an AC power from the AC reactor 162 to supply a hydraulic motor 130. Inverter 170 for supplying DC power to the power supply, and a power regenerative unit (PRU) 180 for receiving the back electromotive force of the hydraulic motor 130 from the inverter 170 to reproduce the electromotive force.

The inverter 170 receives a three-phase AC power from the AC reactor 162, converts it into DC power, and supplies the same to the hydraulic motor 130. The inverter 170 may further include a DC reactor 172 for smoothing DC noise and removing noise. In the inverter 170, the power regenerative unit 180 is connected to the DC power terminals D + and D−. Therefore, the inverter 170 supplies power to the hydraulic motor 130 or receives back EMF generated from the hydraulic motor 130.

The power regenerative unit 180 is configured to receive the counter electromotive force of the DC power from the inverter 170, convert it to AC power, regenerate electromotive force, and circulate and supply the inverter to the inverter 170 through the AC reactor 162. As shown in FIG. 4, the power regenerative unit 180 of this embodiment includes a bridge circuit including a plurality of switching elements Q1 to Q6 corresponding to a three-phase AC power source.

That is, the plurality of switching elements Q1 to Q6 are connected between the wires connected to each of the DC power terminals D + and D− of the inverter 170. For example, the power regenerative unit 180 may include first and second switching elements Q1 and Q2 and third and fourth switching elements Q3 and Q4 in a line connected to each of the DC power terminals D + and D−. ), And the fifth and sixth switching elements Q5 and Q6 are connected in series with each other, and the first, third and fifth switching elements Q1, Q3 and Q5, and the second, fourth and fifth The six switching elements Q2, Q4 and Q6 are connected in parallel with each other.

A plurality of diodes D1 to D6 are connected to both ends of each of the first to sixth switching elements Q1 to Q6. In addition, an alternating current reactor is provided between the first and second switching elements Q1 and Q2, the third and fourth switching elements Q3 and Q4, and the fifth and sixth switching elements Q5 and Q6, respectively. (L) is connected. In addition, the power regenerative unit 180 is provided with a capacitor C connected to the wires connected to each of the DC power terminals D + and D- to receive and store back EMF.

The controller 142 is connected to the power regeneration unit 180 through a plurality of drives 146 connected to the gate terminals of each of the first to sixth switching elements Q1 to Q6. For example, one drive is connected to the gate terminals of two switching elements connected in series with each other. Therefore, the drive 146 drives to switch the respective switching elements in response to the control signal output from the controller 142. Therefore, each of the switching elements Q1 to Q6 receives a driving signal from the corresponding driver 146, switches to regenerate electromotive force, and outputs a three-phase AC power through the AC reactor L.

When the rotational speed of the hydraulic motor 130 is decelerated, the power regeneration unit 180 recognizes a control signal output from the controller 142, and electromotive force is generated by the counter electromotive force generated as the rotational speed of the hydraulic motor 130 is reduced. The switching operation of the first to sixth switching elements Q1 to Q6 is controlled. As a result, the power regenerative unit 180 regenerates the counter electromotive force into electromotive force and supplies it to the AC reactor 162 of the inverter controller 144. In this embodiment, the configuration and operation of the inverter controller 144 will be described using AC power, but it will be apparent to those skilled in the art that the operation of the inverter controller 144 can be performed using DC power. Of course, in this case, components such as the circuit breaker 160 and the AC reactor 162 are removed as an option.

Referring back to FIG. 3, the hydraulic pump 120 may be provided as a variable piston pump in the present invention as a device for discharging a fluid, or may be configured as a variable vane pump.

That is, Figure 5 is a cross-sectional view showing the structure of a variable piston pump used in the hydraulic transmission system according to an embodiment of the present invention, Figure 6 is a variable vane pump used in the hydraulic transmission system according to an embodiment of the present invention. 7 is a cross-sectional view showing the structure of FIG. 7 and FIG. 7 is a graph showing power consumption used according to time of the hydraulic transmission system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the variable piston pump 120 is a device for discharging fluid by suitably moving a plurality of pistons 121 installed in the axial direction, and the inclined plate 123 and the piston head 121a have a spring 124. Since the piston 121 is always closed by the inclined plate 123 while rotating the drive shaft 125, the piston 121 reciprocates.

When the piston 121 reciprocates, suction and discharge are performed by the valve plate 126, and the discharge flow rate of the piston 121 is changed by the inclination of the inclined plate 123.

In addition, the hydraulic pump 120 is a device for flowing a fluid corresponding to electricity to receive the mechanical energy from the outside by a motor or an engine to provide fluid energy according to the pressure and flow rate of the working fluid, the general of the hydraulic pump 120 The operation first creates a vacuum section at the inlet lower than atmospheric pressure, thereby sucking the fluid and rotating the sucked fluid and supplying it to the circuit through the outlet at a constant pressure and flow rate. Will be displayed.

As another example, as shown in FIG. 6, the variable vane pump 120a includes a cylinder 127 having a larger diameter and a cylinder 128 having a smaller diameter. It is configured to rotate eccentrically with respect to the large cylinder 127, and the cylinder 128 having a small diameter is provided with a plurality of vanes 129 to move the rotation toward the center.

Then, when the cylinder 128 with a smaller diameter rotates, the vane 129 is in close contact with the inner wall of the cylinder 127 having a larger diameter by centrifugal force, and the vane 129 has a diameter due to the rotation of the cylinder 128 having a smaller diameter. It rotates in close contact with the inner wall of this large cylinder 128.

Here, when the cylinder 128 having a smaller diameter rotates, the fluid is sucked at the point where the volume between the vanes 129 and the vane 129 increases, and the fluid is discharged at the point where the volume decreases to variably discharge the fluid. So that the capacity can be varied.

One side of the hydraulic pump (120, 120a) is provided with a pressure sensor 122 that can measure the size of the discharged hydraulic pressure, the hydraulic motor 130 based on the size of the hydraulic pressure measured by the pressure sensor 122 Measure and calculate the number of revolutions of the hydraulic control unit 140 to send a detection signal.

In addition, when the pressure sensor 122 is electrically connected to the controller 142 and the discharge pressure measured by the pressure sensor 122 is out of an error range of a set value or when hydraulic pressure is not detected, the pressure sensor 122 is removed from the controller 142. The abnormal signal is sent to the alarm unit 190 to prevent a malfunction of the hydraulic transmission system 100.

Hydraulic motor 130 is a device for converting the hydraulic energy of the fluid discharged from the hydraulic pump 120 to a rotational force on one side is provided with a current sensor 132 that can measure the current supplied to the hydraulic motor 130 have.

Like the pressure sensor 122, the current sensor 132 is also electrically connected to the controller 142, and when the current value measured by the current sensor 132 is out of an error range of the set value or no current is detected, An abnormal signal is sent from the controller 142 to the alarm unit 190 to prevent a malfunction of the hydraulic transmission system 100.

Actuate 110 is connected to the discharge port side of the hydraulic pump 120 is a device that is installed to increase the efficiency of energy as a device for increasing the hydraulic energy is introduced into the hydraulic pressure discharged from the hydraulic pump 120 therein .

The inverter controller 144 includes a power supply unit 150 and a power regenerative unit 180. The inverter controller 144 receives the pressure value and the current value sensed by the pressure sensor 122 and the current sensor 132, and receives the hydraulic pump 120. A control signal for controlling the hydraulic motor 130 is output.

The power supply unit 150 is not separately installed outside the hydraulic transmission system 100, it is effective to be integrally formed by modularizing with the inverter control unit 144 inside the hydraulic control unit 140, the power supply unit ( 150) AC power and DC power are used as both.

That is, since a circuit is provided so that any one of DC 24 V, AC 110 V, and AC 220 V can be used without a separate transformer or a rectifier, the hydraulic power transmission unit provided with the power regenerative unit 180 of the present invention is provided. System 100 can reduce the installation space, and can be easily installed and used anywhere.

The power regenerative unit 180 is provided at one side of the inverter controller 144 to convert back electromotive force generated when the rotational speed of the hydraulic motor 130 decreases to electromotive force to supply power to the hydraulic motor 130 again.

That is, the counter electromotive force generated by the hydraulic motor 130 is a current of DC 12 V. When this current is applied to the power regenerative unit 180, the inverter is converted into a three-phase AC current by a switching operation, and then the inverter controller 144. Is supplied to the AC reactor 162 again.

In addition, as described above, one side of the inverter controller 144 does not receive the detection signal for the pressure and current detected by the pressure sensor 122 and the current sensor 132 to the controller 142 of the inverter controller 144. If not, the alarm unit 190 is further provided for generating an alarm sound.

Therefore, the hydraulic power transmission system 100 provided with the power regenerative unit 180 according to an embodiment of the present invention can not only prevent the malfunction of the system but also prevent the system from being damaged due to overcurrent or overload. Can be.

8 is a flowchart illustrating a control procedure of the hydraulic transmission system according to an exemplary embodiment of the present invention, and FIG. 9 is a flowchart sequentially describing a procedure of controlling the hydraulic motor of the hydraulic transmission system illustrated in FIG. 8. .

8 and 9, first, when power is applied in step S1 to drive the hydraulic motor 130, the supply current of the power supplied from the inverter 170 to the hydraulic motor 130 at the same time in step S2. Measure At this time, the minimum output of the hydraulic motor 130 is driven is about 20 Hz, the maximum output is about 60 Hz, the drive is between about 20 Hz to about 60 Hz. In addition, the supplied power may be supplied with 12 V DC or 110 V AC and 220 V AC. When 110 V AC and 220 V AC are supplied, the hydraulic motor 130 is converted into DC by the inverter 170. Is supplied.

Specifically, referring to FIG. 9, when the power supply S1 of the hydraulic motor is supplied in step S11, the state of the setting switch is checked in step S12. The setting switch (not shown) is provided with a plurality of buttons connected to the power regenerative unit 180, through which the operating switch, abnormality occurrence, reset, and the like of the hydraulic transmission system 100 are set. For example, the setting switch may input a command for setting an operation mode such as full operation or static operation, or set an operation mode such as operation, stop, emergency stop, and fault release. have.

Therefore, in steps S13 to S23, the hydraulic motor 130 is driven in response to the setting state of the setting switch.

Referring back to FIG. 8, when the hydraulic motor 130 is driven, the fluid is pumped to the actuator 110 by the hydraulic pump 120 in step S3. In step S4, the discharge pressure discharged from the hydraulic pump 120 through the pressure sensor 122 is measured to measure the rotational speed of the hydraulic motor 130.

The fluid is doubled as the fluid is pumped into the actuator 110, and the measured rotational speed of the hydraulic motor 130 is transmitted to the controller 142 of the flow control unit 140 in real time, and the hydraulic motor 130 is targeted. To reach the rotational speed, the controller 142 outputs a control signal to adjust the amount of current supplied from the inverter 170 to the hydraulic motor 130.

Here, if the rotational speed of the hydraulic motor 130 is greater than about 20 Hz in a state where the discharge hydraulic pressure is greater than the reference pressure, as shown in FIG. 9, the output of the hydraulic motor 130 is reduced; Control to drive continuously at 20 Hz.

If the rotational speed of the hydraulic motor 130 is less than about 60 Hz while the discharge hydraulic pressure is less than the reference pressure, the hydraulic motor 130 is driven at about 60 Hz. Otherwise, the output of the hydraulic motor 130 is output. Will increase. This series of processes is repeated in real time so that the output of the hydraulic motor 130 is driven between about 20 Hz and about 60 Hz to maximize energy efficiency.

When the deceleration state of the rotational speed of the hydraulic motor 130 occurs in step S6, the counter electromotive force generated in step S7 is applied from the inverter 170 to the power regenerative unit 180 to be reproduced as electromotive force, and is reproduced in step S8. The electromotive force thus obtained is circulated and supplied to the AC reactor 162 of the inverter controller 144 and supplied to the inverter 170. As a result, by supplying the driven electromotive force by the electromotive force to the hydraulic motor 130, the power consumption is reduced and the energy efficiency is increased.

In addition, when an abnormality occurs or is not performed in any one of the above-described step S1 to step S8, a step of generating an alarm sound in the alarm unit 190 may be further performed to prevent malfunction of the system. In addition, the system can be prevented from being damaged due to overcurrent or overload.

Table 1 compares the power consumption, noise, and temperature increase of the hydraulic power transmission system 100 and the conventional hydraulic power transmission system shown in FIG. 1 according to an embodiment of the present invention.

Evaluation item

unit
Invention
Conventional
certification
Power Consumption

W
230
840
Korea Institute of Machinery & Materials
noise

dB
60
80
Korea Institute of Machinery & Materials
Temperature increase

℃
5
12
Korea Institute of Machinery & Materials

Here, the calculation of power consumption efficiency is performed by operating the power analyzer for about 48 hours, and then measuring the incoming current and the computed power amount. Although this was about 840 W or more, it can be seen that in the hydraulic power transmission system 100 according to the present invention, the average power consumption is reduced by about 70% or more by about 230 W.

In addition, the noise measurement method was measured using a simple sound level meter at various locations of about 0.5 m in height from about 1 m away from the hydraulic transmission system 100 of the present invention, but in the conventional hydraulic transmission system was about 80 dB, In the hydraulic transmission system 100 according to the invention it can be seen that the noise of about 25% is reduced to about 60 dB.

In addition, the method of measuring the fluid temperature circulating inside the hydraulic transmission system is operated at about 4 hours continuously in the hydraulic pressure system of the present invention at a height of about 100 mm from the bottom of the actuator 110 It measured using the oil temperature meter. As a result, in the conventional hydraulic transmission system is increased by about 12 ℃, in the hydraulic transmission system 100 according to the present invention it can be seen that about 5 ℃ to increase the heat generation of the device is reduced by about 58%.

In the above, the hydraulic transmission system of the present invention and a control method thereof have been described through preferred embodiments, but this is not intended to limit the technical scope of the present invention, it is only intended to help understanding of the invention. Not only that, those skilled in the art to which the present invention pertains may make various changes or modifications without departing from the technical gist of the present invention, and such changes or modifications may be applied to the interpretation of the claims. It goes without saying that it is within the technical scope.

100: hydraulic power system 110: actuator
120, 120a: hydraulic pump 122: pressure sensor
130: hydraulic motor 132: current sensor
140: hydraulic control unit 142: controller
144: drive control unit 146: drive
150: power supply unit 160: breaker
162: AC reactor 170: inverter
172: DC reactor 180: power regenerative unit
190: alarm unit

Claims (11)

In a hydraulic power system:
A hydraulic pump for variably adjusting the pressure of the fluid supplied to the actuator;
A hydraulic motor for variably driving the hydraulic pump by receiving power;
A pressure sensor for measuring a discharge pressure of the hydraulic pump;
A current sensor for measuring a supply current to the hydraulic motor;
And a hydraulic control unit for supplying the power to the hydraulic motor, receiving the discharge pressure measured from the pressure sensor, receiving the supply current measured from the current sensor, and variably controlling the rotational speed of the hydraulic motor. ;
The hydraulic control unit is formed on one printed circuit board and modularized;
A power supply unit for supplying power;
Accepts the discharge pressure measured from the pressure sensor, receives the supply current measured from the current sensor, variably controls the rotational speed of the hydraulic motor, and determines whether the rotational speed of the hydraulic motor is decelerated from the current sensor A controller for detecting;
Receiving power from the power supply unit and supplying power to the hydraulic motor, and when the rotational speed of the hydraulic motor is decelerated from the controller, receives the counter electromotive force generated by the deceleration of the rotational speed to reproduce the electromotive force to the power of the hydraulic motor And an inverter control unit for resupply. delete The method of claim 1,
The inverter control unit;
An inverter for receiving direct current or alternating current power from the power supply and supplying direct current power to the hydraulic motor;
And a power regenerative unit for receiving the counter electromotive force from the inverter and regenerating the electromotive force to supply the inverter to the inverter under the control of the controller. The method of claim 3, wherein
The inverter control unit;
An AC reactor which receives AC power from the power supply and smoothes current and removes noise to supply the inverter to the inverter;
And a direct current reactor installed in the inverter to smooth the DC power of the inverter or remove noise. The method of claim 4, wherein
The power regenerative unit;
It is composed of a bridge circuit having a plurality of switching elements between the wiring connected to the inverter;
And the switching elements are switched by the controller to output the counter electromotive force of the direct current power to the electromotive force of the alternating current power to supply the inverter to the inverter. The method of claim 1,
The hydraulic pump is a hydraulic transmission system, characterized in that a variable piston pump or a variable vane pump is used. The method according to any one of claims 1 and 3 to 6,
The hydraulic transmission system;
And an alarm unit for generating an alarm sound when an abnormality occurs in the discharge signal measured by the pressure sensor and the current sensor and the detection signal for the supply current. In the control method of the hydraulic electric system:
Supplying power to drive a hydraulic motor;
Measuring a supply current supplied to the hydraulic motor;
Pumping fluid into an actuator by driving a hydraulic pump by the hydraulic motor;
Measuring a rotational speed of the hydraulic motor by measuring a discharge pressure discharged from the hydraulic pump;
Variablely controlling the hydraulic motor in response to the measured discharge pressure and the rotational speed;
Receiving the counter electromotive force from the hydraulic motor and reproducing the electromotive force when the measured rotation speed is reduced;
And re-supplying the electromotive force to the power of the hydraulic motor. delete The method of claim 8,
Driving the hydraulic motor;
Receiving AC power and converting it into DC power to supply DC power to the hydraulic motor;
The regenerating may include receiving the counter electromotive force of the DC power and regenerating the electromotive force of the AC power. The method according to claim 8 or 10,
The method comprising:
If an abnormality occurs in the hydraulic transmission system, the control method of the hydraulic transmission system further comprising the step of generating an alarm sound.

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