KR20120110371A - Electric excavator system - Google Patents

Abstract

PURPOSE: An electric excavator system is provided to improve work efficiency by widening the operation range of an excavator and to stably and uniformly charge storage batteries. CONSTITUTION: An electric excavator system comprises a power supply unit and a power receiving unit. The power receiving unit comprises a charge-discharge control unit(215), a power distribution setting unit(340), and a generator power control unit. The charge-discharge control unit controls the charge and discharge of storage batteries(210a,210b,210c). The power distribution setting unit distributes the charging and discharging power of the storage batteries. The generator power control unit controls power generated from a motor generator and supplies the controlled power to the storage batteries. [Reference numerals] (110) Power box; (120) Cable drum; (122) Drum driving unit; (130) Cable guide; (210a,201b,210c) Storage battery; (212) Overcharge prevention unit; (214) Storage amount detection unit; (215) Charge-discharge control unit; (220) Inverter; (230) Traveling motor generator; (232) Turning motor generator; (240) Controller; (250) Alarm unit; (260) Hydraulic lamp; (270) Hydraulic control valve; (274) Boom cylinder; (276) Arm cylinder; (278) Bucket cylinder; (280) Switch; (310) Generator output setting unit; (320) Charge power setting unit; (330) Discharge power setting unit; (340) Power distribution setting unit; (350) Generator power control unit; (AA) External power source; (BB) Explanatory notes; (CC) Mechanical coupling; (DD) Electrical coupling; (EE) Hydraulic motion

Description

Electric Excavator System {ELECTRIC EXCAVATOR SYSTEM}

The present invention relates to an electric excavator system, and more particularly, to include a storage battery therein, so that the power supply unit and the power receiving unit can be operated in a separated state, so that a long distance work can be performed without space constraints. The present invention relates to an electric excavator equipped with an improved battery power distribution function to increase the life of a storage battery by performing a control for appropriately distributing the charging and discharging power of each storage battery so that charging and discharging is performed stably.

In general, an excavator is a construction machine with various work functions, such as excavation work to dig or fill the ground during construction and civil works, breaker work such as soil and rock crushing, compactor work such as soil compaction, and crusher work such as cutting. Say.

Such an excavator is usually equipped with an engine such as a diesel engine to obtain driving power, and uses the power of the engine to drive a hydraulic pump, and supply hydraulic oil discharged from the hydraulic pump to a hydraulic actuator such as a hydraulic motor or a hydraulic cylinder. As a result, each work part such as a traveling crawler or tire rotation, a boom, an arm or a bucket is operated.

Since such a well-known excavator is equipped with an engine such as a diesel engine, it has the advantage of being able to work freely without being restricted in the work place.

However, diesel, which is a fossil fuel, is gradually being depleted, and the necessity of alternative energy is seriously raised, and fuel costs are high, and fuel consumption is particularly high due to the peculiarity of heavy equipment.

As part of solving this problem, an electric excavator using electric energy has been disclosed.

The disclosed electric excavator, for example, by replacing the engine for driving the excavator with an electric motor, as shown in the example of FIG. 1 and by supplying the power for driving the motor from an external power source through the cable 10 to reduce the fuel cost by more than 70% For example, an external power box 20, a cable drum 22 to wind the cable 10, and a cable guide 24 to pivot the cable 10 so as to supply power from the outside. And an induction guide 30 installed in the excavator to guide the cable 10 guided out through the cable guide 24 to the excavator safely.

Thus, the driving of the excavator uses an engine-based electric motor mounted on the excavator, and the various work functions of the excavator use the hydraulic operation through the hydraulic pump as it is, but control the driving of the hydraulic pump by an electric motor. The function of was performed as it is.

However, since the electric excavator is structured to be powered using the cable 10, the range in which the excavator can operate is limited.

That is, since the work can be performed only within the range of the cable 10, the working radius is very limited, and the remote work is not possible, which causes a lot of inconveniences.

In addition, even if the remote operation is possible by using a battery, because the capacity of the battery has a limit, it is also difficult to work for a long time.

As a means for solving the problem, a method of selectively switching the battery using a plurality of batteries as needed may be proposed, and in addition, a method for extending the service life may be better.

In general, a battery used in an electric excavator is composed of a plurality of cells, all initially have the same performance, but as the operation of the electric excavator increases the performance of the cells of the battery.

Nevertheless, since the output of the motor is usually controlled based on the maximum output the battery can produce, after a certain point, the battery cells are discharged in a state exceeding the allowable discharge output. Shortened.

In addition, overcharging or overdischarging may be performed according to the charging and discharging of the battery, and in this case, the difference between the charging power and the discharging power of each battery may increase, thereby overloading other control elements or inputting or outputting power. This instability has a problem that may cause a failure in the operation of the excavator, in which case the shortening of the life of the battery is further accelerated.

The present invention was created in view of the above-mentioned problems in the prior art as described above. In the cable type electric excavator, the operating range of the excavator is extended to a farther distance than the cable, and thus the working range can be expanded. In addition to maximizing and switching the use of a plurality of batteries, a wide range of applications can be performed to ensure stable long-distance work for a long time, but to prevent overcharging and overdischarging according to the condition of the battery. The main purpose is to provide an electric excavator having a battery power distribution function to be distributed so that the charging and discharging of the batteries is performed stably.

Electric excavator system of the present invention for achieving the above object, the input of an external power source to the charging voltage, including a power box including a plurality of control buttons, cable drum, cable drum provided to wind or unwind the power transmission cable A power supply unit including a drum driving unit controlling a rotation driving unit and a cable guide connected to the power box and guiding the charging cable wound around the cable drum so as not to be tangled or twisted; A plurality of batteries including a cable connector to which the cable of the power supply unit can be connected / disconnected, a motor generator, and a controller, and charged with electricity supplied through regenerative braking of the motor and the motor generator; An overcharge protection unit for preventing overcharge under control, a storage capacity detection unit connected to the storage batteries and detecting a charge / discharge state including a potential difference of the storage battery and outputting the detected charge / discharge state to a controller and a power distribution setting unit. A power receiver comprising an inverter for converting a DC power supply to an AC power supply to an electric generator and a controller connected to the controller and transmitting an alarm when the detection potential of the batteries is lower than the reference potential; wherein the power receiver is the storage battery. Detects the state of charge or discharge of each battery A charge / discharge control unit configured to perform charge / discharge during driving within a range of a predetermined voltage or current; and charging state information of each of the accumulators of the power storage amount detection unit is input to the generator power control unit or the charge / discharge control unit. A power distribution setting unit for outputting a control signal, and distributing charge / discharge power of the batteries to uniformly perform charge / discharge of each battery by outputting discharge power control signals of the respective batteries; Characterized in that it further comprises; generator power control unit for controlling the power generated by the motor generator in accordance with the control signal of the power distribution setting unit to supply to each storage battery.

The power receiver may further include a generator output setting unit configured to generate a generator output signal and output the generator signal to a power distribution determining unit according to the state of charge of each battery detected by the electricity storage amount detector. And a discharge power setting unit for outputting to the power distribution determining unit and generating a discharge power setting signal and outputting the discharge power setting signal to the power distribution determining unit.

The power receiver is further provided with a switching switch for switching the connection between the battery and the inverter under the control of the controller when the potential of each battery is lower than the reference potential; The controller further includes a memory unit storing a discharge output value according to a state of charge (SOC) of the storage battery and an internal resistance value for each temperature as a table; A temperature sensor is further installed in the storage battery; The controller further includes a calculation unit for calculating the current and voltage based on the potential value detected by the temperature sensor and the capacitance detection unit, and then calculates the internal resistance by dividing the voltage by the current; The discharge output is controlled according to an experimental internal resistance table value stored in a memory unit corresponding to the calculated internal resistance.

In this case, the controller is characterized in that the discharge output control of the battery is stopped when the battery falls below the reference potential.

According to the present invention, by separating and combining the power supply unit and the power receiver unit, eliminating the constraints of the work space, improving the work efficiency, eco-friendly and reduce fuel costs, long distance work is possible, as well as constant charge and discharge of individual batteries It can be carried out in the voltage and current range, by allocating the charge or discharge power of the batteries to prevent the occurrence of overcharge or over-discharge in a specific battery can be obtained the effect of extending the life of the battery.

1 is an exemplary view of a conventional cable type electric excavator.
2 is a block diagram illustrating the construction of the electric excavator system according to the present invention.
3 is a schematic functional block diagram of an electric excavator system having a battery charge / discharge power distribution control function according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The electric excavator system according to the present invention has the concept of the conventional cable type electric excavator described above, including the charging concept, and receives power when needed, uses charged power when working, and secures the voltage required for the work. It is configured to detect whether it is doing so and to charge it when necessary.

In this regard, reference is made to FIG. 2, which shows a block diagram of an electric excavator system according to the invention.

As shown in Figure 2, the electric excavator system according to the present invention is configured to separate the power supply unit 100 and the power receiver 200.

At this time, the power supply unit 100 is installed in a place for supplying power from the outside as before, the power receiver 200 is installed in the excavator body.

In addition, the power receiver 200 is provided with a cable connector (meaning a plug and a socket, not shown) so as to be connected to the power supply unit 100.

More specifically, as shown in FIG. 2, the power supply unit 100 includes a power supply box 110, a cable drum 120, and a drum driver 122 and a cable guide 130 that control rotation of the cable drum 120. ).

In this case, the power box 110 is provided with a plurality of control switches, so that the external power is connected to supply the necessary power supplied from the external power source to the power receiver 200 when connected to the power receiver 200. It is designed.

In addition, the power supply unit 100 may be installed in plural as necessary, if a large working radius is installed a plurality at appropriate intervals to provide ease of connection through the power receiver 200 to further improve workability. Can be.

In addition, the cable drum 120 facilitates cable management to a short distance as well as to a long distance while winding or releasing a cable (Cable) for transmitting power controlled through the power box 110.

In this case, the cable drum 120 may be driven by a power source, the drive motor may be a drive motor, it may also be controlled by the drum drive unit (122).

In addition, the cable guide 130 is a structure that is guided so that the cable is not tangled or twisted power supply may have the form of the existing cable guide illustrated in FIG.

In this case, the cable guide 130 guides the cable drawn out from the cable drum 120 in which the cable is wound so as to smoothly withdraw the cable to a predetermined length range.

On the other hand, the power receiving unit 200 includes a driving motor generator 230 as a driving driving source, the driving motor generator 230 is in the form of AC power in the state in which the DC power is switched to the AC power through the inverter 220 Will be powered by

In this case, the inverter 220 is controlled by the controller 240.

In addition, the driving motor generator 230 is connected to the hydraulic pump 260 to be controlled through the controller 240.

In addition, the power supply unit 200 according to the present invention further includes a swing motor generator 232 capable of rotating the excavator body mounted with the boom 360 ° with respect to the main body.

In addition, they take the form of an electric motor and a generator to obtain electrical energy through regenerative braking, and the regenerative electricity obtained through regenerative braking is recovered and stored in the battery 210.

As such, since the regenerative braking can be used to accumulate electricity to the storage battery 210, it is possible to reduce heat generation due to driving and to recycle energy.

Of course, the swing motor generator 232 is also controlled by the controller 240.

In addition, the controller 240 may include a predetermined memory.

In addition, a hydraulic control valve 270 is connected to the hydraulic pump 260, and the hydraulic oil discharged by the hydraulic pump 260 is boom cylinder 274 and an arm cylinder according to the control sequence of the hydraulic control valve 270. 276, the bucket cylinder 278 is driven.

That is, since only the drive of the hydraulic pump 260 is electrically coupled, the controller 240 is controlled by the controller 240 to selectively receive the driving force of the driving motor generator 230, but the hydraulic oil generated by the driving of the hydraulic pump 260 thereafter. The hydraulic circuit associated with the supply of is made as before through the opening and closing control of the hydraulic control valve 270.

And the storage battery (210a, 210b, 210c) for supplying power to the driving motor generator 230 is provided, the storage battery (210a, 210b, 210c) has a capacity to supply sufficient power for driving the excavator. Since the storage batteries 210a, 210b, and 210c are DC-type, as described above, DC power is supplied to the traveling motor generator 230 through the inverter 220 to AC power, and a plurality of batteries are installed and the charging voltage is constant. That is, it includes a switching switch 280 to be replaced with another storage battery when it falls below the reference potential to work.

In this case, the changeover switch 280 is installed between the inverter 220 and the storage batteries 210a, 210b, and 210c, and is controlled by the controller 240.

Here, the three storage batteries 210a, 210b, 210c has been described as an example, but this is only a preferred embodiment and can be installed more of course.

Therefore, when three or more batteries are used while changing a single battery, the working time can be extended by that amount, and the working efficiency can be improved for a long time at a long distance.

In addition, the storage batteries 210a, 210b, and 210c are connected to the cable drawn out through the cable guide 120 and the cable connector and configured to be chargeable.

In other words, in a state in which a proper amount of power is charged, the driving motor generator 230 may be driven by being separated from the power supply unit 100 to freely expand and expand the working range of the excavator.

However, as described above, when the charged power falls below a certain level, it is difficult to perform the operation of the excavator, so it can be solved by checking the connection in advance and switching the connection to another battery having a sufficient amount of storage. Accordingly, the work efficiency does not need to be moved back to the power supply unit 100 for charging during the remote work.

To this end, in the present invention, the storage capacity detection unit 214 is further installed in the storage batteries 210a, 210b, and 210c, and at the same time, the overcharge preventing unit 212 can prevent damage to the storage batteries 210a, 210b and 210c due to overcharging. ) And a charge / discharge control unit 215 is installed.

At this time, the overcharge prevention unit 212 and the power storage detection unit 214 are all connected to the controller 240 is configured to be controlled by the controller 240, these overcharge protection unit 212 and the power storage detection unit to prevent overcharge It is preferable to have a kind of circuit form, such as a circuit and a capacitance detection circuit.

In addition, the capacitance detecting unit 214 detects an internal resistance that varies according to SOC (State Of Charge) and temperature of the batteries 210a, 210b, and 210c, and a method of estimating potential by estimating an electric potential. The amount of electricity stored in the 210a, 210b, and 210c, that is, the potential can be detected, and the voltage of both ends of the batteries 210a, 210b and 210c, which is the simplest method, is detected and transmitted to the controller 240, and the controller 240 ) Is preferably configured to check and control the charging by comparing the received detection potential with a reference potential required for driving.

In addition, when it is determined that the potential of the battery currently being used is lower than the reference potential through the storage amount detecting unit 214, the changeover switch 280 is connected to the inverter 220 with an adjacent storage battery having sufficient storage capacity under the control of the controller 240. Switch. In addition, the capacitance detection unit 214 has a battery temperature sensor, a current sensor, and a voltage sensor therein, and is configured to detect the charging state information of each battery and output the power distribution determination unit 340.

The state of charge information by the power storage detection unit 214 detects the output current of the batteries 210a, 210b, and 210c by using a current sensor and a voltage sensor and multiplies the voltage between the battery terminals, and calculates a power amount. It can be obtained by calculating a proportional formula for the amount of power at the preset maximum charge.

The charge / discharge control unit 215 is configured to be connected between the cable guide 130, the power switch 280 and the pre-rotational power generator 232, the driving motor generator 230 and the storage battery (210a, 210b, 210c) reference voltage To compare the voltages of the batteries 210a, 210b, and 210c, and compare the reference current and the discharge current of the batteries 210a, 210b, and 210c to charge or discharge the batteries 210a, 210b, and 210c. Charge and discharge of the storage battery (210a, 210b, 210c) to be performed within the range of.

That is, the charge / discharge control unit 215 compares the reference voltage with the voltage of each of the batteries 210a, 210b, and 210c so that the voltage of each of the batteries 210a, 210b, and 210c exceeds a predetermined voltage range including the reference voltage. When the charge of each of the storage battery (210a, 210b, 210c) is cut off. In addition, when the discharge current of each of the batteries 210a, 210b and 210c is out of a range of current values including the reference current by comparing the discharge current and the reference current of each of the batteries 210a, 210b and 210c. The discharge of the 210a, 210b, and 210c is blocked. As a result, the charge / discharge control unit 215 allows each of the storage batteries 210a, 210b, and 210c to be uniformly charged or discharged.

In FIG. 2, the charge / discharge control unit 215 and the power switch 280 are connected by one control and power line, and the charge / discharge control unit 215 and all the storage batteries 210a, 210b, and 210c are also connected by one control and power line. Although illustrated as being, the charge / discharge control unit 215 and the power switch 280 are each battery 210a, 210b, so that the charge and discharge control unit 215 can independently control each of the storage battery (210a, 210b, 210c) In order to supply the power of the 210c to the power switch 280 individually, the control and the power corresponding to the number of the storage batteries 210a, 210b and 210c are connected. The cable guide 130 or the charge / discharge control unit 215 and the storage batteries 210a, 210b and 210c may also independently control the charging and discharging control unit 215 to charge the respective storage batteries 210a, 210b and 210c. Control corresponding to the number of accumulators 210a, 210b, and 210c to divide the input power of the pre-rotational motor generator 232 or the traveling motor generator 230, respectively, and supply them independently to the respective accumulators 210a, 210b, and 210c. And a storage battery 210a, 210b, 210c by a power supply line.

Examples of circuits constituting the charge / discharge control unit 215 (not shown) include a voltage error amplifier ERROR AMP that amplifies and outputs an error ERROR of a voltage command V_ref, a capacitor, and a battery feedback voltage V_fb; An output error amplifier comprising a current error amplifier that amplifies and outputs an error of the current command I_ref and the capacitor and the feedback current flowing through the battery during charging and discharging, and two diodes connected to the output of the voltage error amplifier and the current error There is a charge / discharge switching circuit composed of two resistors connected to the amplifier output, and the diode and resistor are connected in common to the non-inverting input (+) terminal of the voltage follower to drive the charge control signal. It is connected to the non-inverting input (+) terminal of the voltage follower so as to drive the discharge control signal in common. There is a driver circuit part configured to be able to operate, and in the charging part, the drain of the N-type FET (Field Effect Transistor) (FET1, FET2) is connected to the positive power terminal (+ V). The output of the voltage follower amplifier is connected to the gate resistors R3 and R4 of the FETs FET1 and FET2, respectively, and in the discharge part, the drain of the P-type FETs FET3 and FET4 is negative. A circuit is connected to the terminal (-V) and the output of the voltage follower amplifier IC4 is connected to the gate resistors of the FETs FET3 and FET4, respectively.

In the case of the charging unit, resistors used for current limiting during charging and discharging are connected in common with the source of the N-type FETs (FET1, FET2) and the source of the discharge unit (P3). Since the drain-source resistance value is small when the FETs are connected in parallel, overcurrent may flow toward the smaller RDS value among the FETs connected in parallel when there are no resistors. Thus, adding resistors with a larger resistance value than RDS can be used to balance charge / discharge currents of parallel-connected FETs.

In the above configuration, the reference voltage V_fb and the feedback current I-fb are compared with the reference voltage V_ref and the reference current I_ref as the voltages and currents of the storage batteries 210a, 210b, and 210c, respectively. During the driving of the 210b and 210c, the voltage and the current of each of the storage batteries 210a, 210b and 210c are compared with the reference voltage and the reference current to control charging and discharging in a constant voltage range and current range.

The charge / discharge control unit 215 is not limited to the above example, and various circuit configurations for controlling charging and discharging of the storage battery may be applied according to reference voltage and reference current values.

In addition, the power receiver 200 distributes and controls the charging or discharging power to the respective storage batteries so that overcharging or overdischarging does not occur according to the state of charge of the storage batteries 210a, 210b, and 210c.

To this end, as shown in FIG. 2, the power receiver 200 includes a generator output setting unit 310, a charging power setting unit 320, a discharge power setting unit 330, a power distribution determining unit 340, and a generator power control unit ( It is configured to further comprise 350.

The generator output setting unit 310 is each of the storage batteries (210a, 210b, 210c) from the generator power control unit 350 in accordance with the charging state information of the storage batteries (210a, 210b, 210c) input from the storage capacity detection unit 214 Generates a signal for controlling the charging power to be supplied to the power distribution output unit 340.

The charging power setting unit 320 generates a charge / discharge control signal for controlling each of the storage batteries 210a, 210b, and 210c to perform a uniform charging or discharging within a predetermined voltage and current range. Output to 340.

The discharge power setting unit 330 calculates the maximum discharge power at each temperature according to the temperature information of each of the storage batteries 210a, 210b, and 210c detected by the storage amount detection unit 214, and the power distribution setting unit Output to 340.

The generator power control unit 350 is provided between the driving motor generator 230 and the turning motor generator 232 and the storage batteries 210a, 210b, and 210c according to the control signal of the power distribution determining unit 340. By controlling the power generated by the 230 and the pre-rotational power generator 232 to supply to each of the storage battery (210a, 210b, 210c) to control the supply of the generated power supplied to the storage battery.

The power distribution setting unit 340 controls the generator power control unit 350 according to a signal for controlling the charging power input from the generator output setting unit 310 to accumulate the batteries 210a and 210b by the power generated by the motor generators. , 210c) to prevent overcharging.

In addition, the power distribution setting unit 340 controls the charge / discharge control unit 215 according to the input charge / discharge control signal so that each of the storage batteries 210a, 210b, 210c is uniformly charged within a predetermined voltage and current range. Allow discharge to be performed.

In addition, the power distribution setting unit 340 charges and discharges each of the storage batteries 210a, 210b, and 210c so as not to discharge more than the maximum discharge power based on the maximum discharge power value input from the discharge power setting unit 330. The control unit 215 is controlled.

Further, as shown in FIG. 3, the temperature sensors 290 are installed in the storage batteries 210a, 210b, and 210c, respectively, and the temperature sensor 290 is connected to the controller 240 to detect the detected temperature value of the controller ( 240). The temperature sensors 290 may be a temperature sensor installed in the capacitance detection unit 214 or a temperature sensor additionally installed.

In addition, the controller 240 includes an operation unit 292 and a memory unit 294, and includes the operation unit 292 and the memory according to the temperature detection value of the temperature sensor 290 and the detection value of the power storage detection unit 214. The discharge unit 294 controls the discharge output of the storage batteries 210a, 210b, and 210c.

That is, the maximum allowable discharge output is controlled based on the SOC (state of charge) and the temperature of the batteries 210a, 210b, and 210c, which are internal to the batteries 210a, 210b, and 210c by these factors. This is because the resistance is different.

Accordingly, in the present invention, the driving conditions of the present invention are stored in the memory unit 294 in a state in which the internal resistance change of SOC and temperature storage batteries 210a, 210b, and 210c and the ideal discharge output value thereof are stored as table values through experiments. The internal resistance is calculated according to the method, and the value is compared with the stored value stored in the memory unit 294 to control the discharge output of the batteries 210a, 210b, and 210c to a value corresponding thereto. 210c) enables management.

At this time, the method of measuring the internal resistance is determined by the value of the voltage change divided by the current when the current flows to the battery to be tested, and when the internal resistance is determined in this way through the following equation (Equation 1), (Equation 2) The discharge output P can be determined.

-----------------(식1)

----------------- (Eq. 1)

-------------------------(식2)

------------------------- (Equation 2)

(R: internal resistance, ΔV: difference between the maximum voltage (V _LIMIT ) and the current voltage (V _CURRENT ) of the battery)

Here, if the output P is a negative value, the discharge output is a positive value. If the output P is a negative value, the discharge output is a charge output. In the present invention, since only an electric motor excluding a generator is used, the charge output will not be discussed.

As a result, in the present invention, the controller 240 receives the potential value detected through the capacitance detection unit 214, calculates an amount of change in current and voltage in the calculation unit 292, calculates an internal resistance, and stores the battery temperature at that temperature. The battery 210a, 210b, by adjusting the temperature detected by the sensor 290 and the value corresponding to the calculated internal resistance from the table value stored in the memory unit 294 to the discharge output presented in the table accordingly. The life of 210c) can be extended.

In addition, when the storage batteries 210a, 210b, and 210c are below the reference voltage, it is preferable to stop the discharge output adjustment.

In addition, the alarm unit 250 is connected to the controller 240.

The alarm unit 250 is preferably configured to flash the warning light while emitting an alarm sound so that the excavator driver can see visually.

The alarm unit 250 is operated under the control of the controller 240 when the detection potential of the storage batteries 210a, 210b, and 210c of the power storage detection unit 214 does not reach the reference potential. By driving toward the power supply unit 100 to connect the cable provided in the power supply unit 100 to the power receiver 200 to perform the charging operation.

In this case, the alarm unit 250 may generate an alarm for each discharge of each battery, and may be configured to generate an alarm when all the batteries are discharged. Preferably, only the warning lamp flashes during discharge of each battery. When all of the batteries are discharged, it is particularly preferable to generate a warning light and an alarm sound so that the batteries can be recognized visually.

In addition, the term "discharge" described in the present invention is not defined as a discharge concept commonly used, but is defined as meaning when the potential of the battery falls below a reference potential (a proper potential required for driving an excavator).

The present invention having such a configuration has the following operational relationship.

First, when the working radius is not far from the power supply unit 100 and is within the length of the cable, the power supply unit 100 and the power receiver unit through the cable connector do not need to separate the power supply unit 100 and the power receiver 200. While maintaining the connection state 200, the work that can be done through the electric excavator, such as excavation work, breaker work, crusher work, etc. are performed.

In this case, since the power is continuously supplied through the power supply unit 100, the driving power and the working power (for driving the hydraulic pump) are sufficient without sufficient force.

On the other hand, if the working radius is out of the cable length is supplied with sufficient power from the power supply unit 100 to sufficiently charge the power required for the storage batteries (210a, 210b, 210c) provided in the power receiving unit 200 or already charged state To be in.

Thus, when charging is complete, the cable connector is disconnected so that the power supply unit 100 and the power receiver 200 are separated.

Here, the output control of the storage batteries (210a, 210b, 210c) according to the discharge, as described above, the table value corresponding to the temperature value detected by the temperature sensor 290 and the arithmetic internal resistance value (stored in the memory unit) It is controlled in accordance with the present invention), so that abrupt discharge change can be suppressed, thereby extending the service life.

Then, the excavator is driven by using the power stored in the storage battery (210a, 210b, 210c), and after moving to the working place to drive the hydraulic pump 260 under the control of the controller 240 to perform the necessary work. .

In addition, when the warning light flashes through the alarm unit 250 during operation, the driver only needs to recognize that the battery is changing.

At the same time, the changeover switch 280 switches the connection between the storage battery and the inverter 220 to a new storage battery under the control of the controller 240.

Then, since the excavator can always be supplied with a power source above the reference potential, there is no problem in driving the driving motor generator 230, and thus, a long distance operation can be performed.

If the audio-visual alarm is generated through the alarm unit 250 even after the operation continues or during the operation, the driver recognizes that the battery needs to be stored, and drives the excavator toward the power supply unit 100 to connect the cable connector. By connecting the power supplied from the power supply unit 100 to charge the storage battery (210a, 210b, 210c), and if sufficient power storage is done again disconnect the cable and then move to the work place to work.

At this time, if a plurality of power supply unit 100 is installed in accordance with the working radius, the time required to move the excavator for charging, thereby reducing the charging time has the advantage that the work efficiency is improved.

As such, the electric excavator according to the present invention may drive the hydraulic motor 260 by driving the driving motor generator 230 replacing the engine by using the storage batteries 210a, 210b, and 210c. It is possible to perform various tasks that can improve the work efficiency and save energy.

First of all, by using a plurality of storage batteries (210a, 210b, 210c) can work for a long time even in the long-distance work has the advantage of significantly improved work efficiency.

100: power supply unit 110: power box
120: cable guide 200: power receiver
210a, 210b, 210c: Storage battery
215: charge and discharge control unit 220: inverter
230: electric motor 240: controller
250: alarm unit 260: hydraulic pump
270: hydraulic control valve 280: changeover switch
290: temperature sensor 292: calculation unit
294 memory section
310: generator output setting unit 320: charging power setting unit
330: discharge power setting unit 340: power distribution determination unit
350: generator power control unit

Claims (4)

In the electric excavator system including a power supply and a power receiver,
The power receiver includes a cable connector to which the cable of the power supply unit can be connected / disconnected; controller; A plurality of storage batteries; Overcharge protection; inverter; An alarm unit; And a storage capacity detection unit connected to the storage batteries and detecting a charge / discharge state including a potential difference between the storage batteries and outputting the detected charge / discharge state to the controller and the power distribution setting unit.
A charge / discharge control unit configured to detect a charging or discharging state of the storage battery so that charging and discharging of the storage battery is performed within a predetermined voltage or current range;
Receives the charging state information of each battery of the storage amount detection unit outputs a signal for controlling the charging power of the battery to the generator power control unit or the charge and discharge control unit, the discharge power control signal of each of the storage battery to the charge and discharge control unit A power distribution setting unit for distributing charge / discharge power of the storage batteries so that the charging and discharging of each storage battery is performed uniformly by outputting the output power;
And an electric generator power control unit for controlling the electric power generated by the electric generator according to the control signal of the electric power distribution setting unit and supplying the electric power to each battery. The method according to claim 1,
The power receiver comprises: a generator output setting unit for generating a generator output as a set signal according to the state of charge information of each battery detected by the power storage amount detecting unit and outputting the generator signal to a power distribution determining unit;
A charging power setting unit configured to generate a charging power setting signal and output the charging power setting signal to the power distribution determining unit;
And a discharge power setting unit configured to generate a discharge power setting signal and output the discharge power setting signal to the power distribution determining unit. The method according to claim 1,
The power supply unit is further provided with a switching switch for switching the connection between the battery and the inverter under the control of the controller when the potential of each battery is lower than the reference potential;
The controller further includes a memory unit storing a discharge output value according to a state of charge (SOC) of the storage battery and an internal resistance value for each temperature as a table;
A temperature sensor is further installed in the storage battery;
The controller further includes a calculation unit for calculating the current and voltage based on the potential value detected by the temperature sensor and the capacitance detection unit, and then calculates the internal resistance by dividing the voltage by the current;
The electric excavator system, characterized in that for controlling the discharge output in accordance with the experimental internal resistance table value stored in the memory unit corresponding to the calculated internal resistance. The method according to claim 3,
And the controller stops controlling the discharge output of the battery when the battery falls below the reference potential.

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