JP6071327B2 - Hybrid type construction machine control method and hybrid type construction machine - Google Patents

Description

  The present invention relates to a hybrid construction machine control method and a hybrid of a capacitor or a capacitor (hereinafter referred to as a storage battery) used in a construction machine or a working machine such as an agricultural machine, particularly a hybrid construction machine powered by an electric motor and an engine. Related to mold construction machinery.

  As one of energy-saving measures in construction machines or agricultural machines, etc., energy that was conventionally discharged as heat, for example, inertial energy when a hydraulic excavator stops turning, potential energy when a crane device is lowered, etc. It is becoming common to convert the energy into electrical energy and reuse it at startup. Japanese Patent Application Laid-Open No. 2004-151867 shows a conventional technique for such energy regeneration.

  Patent Document 1 describes a method of keeping the voltage of the power storage device constant at a set voltage.

  Non-Patent Document 1 was created by the Japan Electronics and Information Technology Industries Association based on JEITA RCR-1001A established for the purpose of improving safety in the entire electronic component and electronic equipment industry. It is described for explanation.

JP 2011-36111 A

Japan Electronics and Information Technology Industries Association Standard JEITA RCR-2370C “Electric Double Layer Capacitor Guidelines (Safety Application Guide for Electric Double Layer Capacitors)” 6.2.3 Applied Voltage

  By the way, in Patent Document 1, it is necessary to set the set voltage so that the voltage of the power storage device does not become equal to or lower than the system operating voltage even when the voltage fluctuation during system driving increases with the deterioration of the power storage device. In the stage, the set voltage is increased more than necessary, and the voltage load of the power storage device is increased to promote deterioration.

  Accordingly, an object of the present invention has been made to solve the above problems, and a hybrid construction machine that suppresses deterioration of a power storage device by adjusting a set voltage of the power storage device in accordance with a deterioration state of the power storage device. It is to provide a control method and a hybrid type construction machine.

  In order to solve the above-described problem, a hybrid construction machine control method according to the present invention provides a set voltage of a power storage device in a hybrid construction machine that cooperatively drives an electric motor supplied with power from the power storage device when driving a hydraulic actuator. In the hybrid type construction machine control method for controlling the power, the actual voltage of the power storage device is measured to determine the deterioration rate from the voltage fluctuation of the actual voltage in the initial state of the hybrid type construction machine and the voltage fluctuation of the actual voltage after operation. The adjustment coefficient is calculated from the operating voltage of the hybrid construction machine and the voltage fluctuation of the actual voltage after the operation, and a new set voltage is calculated from the reference voltage and the adjustment coefficient.

  Furthermore, when the lowest actual voltage due to voltage fluctuations below the set voltage is below the operating voltage lower limit, the adjustment coefficient may be calculated so that the lowest actual voltage exceeds the operating voltage lower limit.

  In addition, when the maximum actual voltage due to voltage fluctuation below the set voltage exceeds the rated voltage upper limit, the adjustment coefficient may be calculated so that the maximum actual voltage falls below the rated voltage upper limit.

  On the other hand, the hybrid construction machine according to the present invention that solves the above-described problems is a hybrid construction machine that controls the set voltage of the power storage device by cooperatively driving an electric motor supplied from the power storage device when driving the hydraulic actuator. Then, the actual voltage of the power storage device is measured to calculate the deterioration rate from the voltage fluctuation of the actual voltage in the initial state of the hybrid construction machine and the voltage fluctuation of the actual voltage after operation, and the hybrid construction machine An adjustment coefficient is calculated from the operating voltage and the voltage fluctuation of the actual voltage after the operation, and a new set voltage is calculated from the reference voltage and the adjustment coefficient.

  By adopting the hybrid type construction machine control method and the hybrid type construction machine according to the present invention, the voltage of the power storage device is less than or equal to the system operating voltage even in the voltage fluctuation at the time of system driving that increases with the deterioration of the power storage device according to the present invention. The set voltage can be set so as not to become a voltage. In the initial stage of deterioration, the set voltage can be set as necessary and sufficient, and the voltage load on the power storage device can be reduced.

1 is a system configuration diagram including a hydraulic circuit of an embodiment in a hybrid type construction machine according to the present invention. It is a block diagram of electric control unit ECU of the Example in the hybrid type construction machine which concerns on this invention. It is a graph about the voltage fluctuation rate about the relationship between an electric motor output voltage, the electrical storage apparatus output voltage, and time in the hybrid type construction machine which concerns on this invention. 6 is a graph showing electric characteristics of a conventional electric double layer capacitor described in Non-Patent Document 1 according to voltage application conditions. It is a flowchart which shows the process of the calculation command program 32 by the hybrid type construction machine control method of the Example in the hybrid type construction machine which concerns on this invention. It is a graph which shows the relationship of the voltage fluctuation | variation of an Example and the motor output (Pm) in the hybrid type construction machine which concerns on this invention. It is a graph which shows the relationship between the adjustment coefficient ((alpha)) and voltage deterioration rate (K) of the Example in the hybrid type construction machine which concerns on this invention.

  The configuration and operation of the hybrid construction machine according to the present invention will be described with reference to FIGS. The configuration will be described first, and the operation will be described.

  A configuration will be described with reference to a system configuration diagram including a hydraulic circuit of an embodiment of the hybrid type construction machine according to the present invention shown in FIG. In the figure, the upper swing body 10 exemplifies a hydraulic motor Hm as a hydraulic actuator for driving an upper swing body (not shown) of the construction machine and a hydraulic drive circuit related thereto, and the upper swing body 10 includes a reduction unit 11 and a gear unit 13. The hydraulic motor Hm and the electric motor Em are coupled to each other. An inverter 12 is coupled to the electric motor Em so that a predetermined current flows through the phase difference wire.

  The inverter 12 has a function of transmitting the output of the electric motor Em and the voltage of the power storage device to the electric control unit ECU.

  Reference numeral 14 denotes a power storage device mounted on the construction machine, which is composed of, for example, a capacitor, and the detection voltage Vact is given to the electric control unit ECU. In addition to the detection voltage Vact of the power storage device, the electric control unit ECU is also supplied with Pm which is the output torque of the electric motor Em. Further, the electric control unit ECU calculates the torque command Tr and supplies the torque command Tr to the inverter 12.

  Reference numeral 16 denotes a hydraulic motor unit including a communication valve 18 connected in parallel with the hydraulic motor Hm. The pressure oil supply / discharge ports A and B of the hydraulic motor Hm are connected to the switching valve 20 via flow paths LA and LB.

  The switching valve 20 is connected to a pilot operation pressure signal from a control stick (not shown) through a flow path. The pump 22 that generates the pressure oil supplied to the hydraulic motor Hm is a variable displacement pump and is configured to be driven by the engine EG. One of the pumps 22 is connected to the switching valve 20 and the other is connected to the tank T.

  The electric control unit ECU will be described with reference to FIG. 2 which is a configuration diagram of the electric control unit ECU of the embodiment in the hybrid construction machine according to the present invention. In the figure, reference numeral 24 denotes an analog / digital conversion unit (hereinafter referred to as an A / D conversion unit), to which an output torque Pm of the electric motor Em and an output Vact of the power storage device 14 are input. The electric control unit ECU further has a function of a calculation device that estimates the deterioration state of the power storage device 14 from the output of the electric motor Em received from the inverter 12 and the voltage of the power storage device 14, and stores the power from the estimated value of the deterioration state based on the calculation result. It has the function of a control device that adjusts the set voltage of the device 14.

Reference numeral 26 denotes a data memory, and the detected signals Pm and Vact are recorded as digital values in the predetermined memory section, and are updated to the latest values at a constant cycle. The data memory 26 also includes Vb that is the rated voltage of the power storage device 14 calculated inside the electric control unit ECU, the set voltage Vset, Vh that is the maximum value of the power storage device voltage, Vl that is the minimum value of the power storage device voltage, a voltage degradation rate K in the initial state, the voltage fluctuation Vo, a memory section such as adjustment factor α is provided in the initial state with no degradation.

  Reference numeral 28 is a central processing unit (hereinafter referred to as a CPU), and reference numeral 32 is a program memory for storing a calculation command program for the CPU 28. Reference numeral 30 denotes a digital / analog converter (hereinafter referred to as a D / A converter), which converts the set voltage Vset and the adjustment coefficient α in the data memory 26 into an analog signal by the D / A converter.

  FIG. 3 is a graph of the voltage fluctuation rate regarding the relationship between the motor output voltage, the power storage device output voltage, and the time when the motor is driven in the hybrid construction machine according to the present invention. In FIG. 3, the horizontal axis is time (sec), the vertical axis is provided with the motor output torque Pm on the left side, and the power storage device voltage Vact on the right side, but the display unit is the ratio (%) to the maximum motor output torque, respectively. It is a ratio (actual voltage fluctuation rate) (%) to the rated output voltage of the power storage device.

  Waveform Vact shows the transition of output voltage Vact of power storage device 14. A waveform Pm shows a transition of the output torque Pm of the electric motor Em. The waveform Pm changes in the negative direction of the motor output to perform the turning acceleration operation, and thereafter changes in the positive direction of the motor output to perform the turning deceleration operation. The waveform Vact initially maintains the set voltage Vset when the motor is driven, and then drops to the minimum value Vl in about 2 seconds by driving the motor for the turning acceleration operation, and then reaches Vh by the regenerative action of the turning deceleration operation. It has been shown to rise.

  Then, operation | movement of the hybrid type construction machine which concerns on this invention is demonstrated using FIGS. 1-3, 5-7.

  First, the case where the turning of the upper turning body 10 is accelerated in the hybrid construction machine according to the present invention will be described.

  The switching valve 20 switches an oil path connecting the hydraulic pump 22 and the hydraulic motor Hm according to the turning direction of the upper swing body 10. The hydraulic pump 22 is driven by an engine EG connected on the same axis, and supplies hydraulic oil sucked from the hydraulic oil tank T to the hydraulic motor Hm via the switching valve 20. The hydraulic motor Hm outputs a rotational force by the high-pressure hydraulic oil supplied from the hydraulic pump 22 and drives the upper swing body 10 via the gear unit 13. The electric motor Em receives the electric power of the power storage device 14 via the inverter 12, is driven by an output based on a command from the electric control unit ECU, and drives the upper swing body 10 in cooperation with the hydraulic motor Hm. The communication valve 18 is in a freely rotating state so as not to output torque by using the hydraulic motor Hm as a loop circuit during operation, but does not operate during acceleration.

  Next, the case where the turning of the upper turning body 10 is decelerated will be described.

  At this time, the switching valve 20 is in the neutral position, and the hydraulic oil discharged from the hydraulic pump 22 is returned to the hydraulic oil tank T without being supplied to the hydraulic motor Hm. The communication valve 18 operates to allow the hydraulic motor Hm to rotate. As a result, the hydraulic motor Hm does not output a braking torque and performs braking only with the electric motor Em. The electric motor Em is rotated by the rotational inertial force of the upper swing body 10, but outputs a braking torque according to a command from the electric control unit ECU, performs rotational braking, converts the rotational inertial force into electric power, and converts the inverter 12 The power storage device 14 is charged via

  That is, the power storage device 14 generates a voltage fluctuation in which the voltage decreases due to the output of the electric motor Em during turning acceleration, and the voltage increases due to charging by the electric motor Em during turning deceleration. The voltage of the power storage device 14 is maintained at a set voltage at which the voltage before turning acceleration is a constant value by adjusting the outputs of the hydraulic motor Hm and the electric motor Em by the electric control unit ECU.

  Subsequently, an operation according to the calculation command program 32 of the electric control unit ECU will be described with reference to FIGS.

  The electric control unit ECU receives the output torque Pm of the electric motor Em and the actual voltage fluctuation Vact of the power storage device 14 from the inverter 12 according to the calculation command program 32 (step a2 in FIG. 5).

The electric control unit ECU calculates the voltage fluctuation Vo in the initial state without deterioration from the output torque Pm of the electric motor Em according to the calculation command program 32 (step a4 in FIG. 5, FIG. 6). Here, since output voltage Vact of power storage device 14 is a voltage fluctuation in a deteriorated state, Vact> Vo.

In addition, FIG. 6 shows the relationship between the voltage fluctuation (V0, Vact) and the motor output (Pm). However, the performance deteriorates with the aging of the power storage device, and the function gradually changes like f ′. I know it will go. Regarding the definition of the function, an approximate curve may be defined from data obtained by a deterioration test of the power storage device, or a three-dimensional matrix table of the motor output (Pm) and the voltage fluctuation with respect to the service life may be used.

  The electric control unit ECU calculates the deterioration coefficient K by dividing the output voltage Vact of the power storage device 14 by the voltage fluctuation Vo in the initial deterioration state according to the calculation command program 32 (step a6 in FIG. 5). This deterioration coefficient represents the deterioration state of the power storage device. K is a numerical value of 1 or more, and the greater the value of K, the greater the deterioration.

The electric control unit ECU calculates α as an adjustment coefficient of the set voltage from the deterioration coefficient K according to the calculation command program 32 (step a8 in FIG. 5, FIG. 7). FIG. 7 shows the relationship between the adjustment coefficient (α) and the voltage deterioration rate (K) in the case where the set voltage Vset = the rated voltage Vb. As for the function g, an approximate curve may be defined from the data of the operation test of the hybrid construction machine, or a two-dimensional matrix table of the adjustment coefficient (α) and the voltage deterioration rate (K) may be used. Good.

In accordance with the calculation command program 32, the electric control unit ECU calculates the set voltage Vset by multiplying the rated voltage Vb of the power storage device 14 preset in the calculation command program 32 by the adjustment coefficient α (a10 in FIG. 5). Process). Rated voltage Vb of power storage device 14 is a set voltage at the initial state with no deterioration of the power storage device, when Vact = Vo K = α = 1, and becomes a Vb = Vset (Figure 7).

  This calculation is mainly performed at a point where the electric motor Em stably outputs a constant torque, so that variations in the calculation result can be suppressed.

  For example, when the upper swing body 10 is decelerated, the hydraulic motor is free to rotate, so there is no need to consider the influence of the hydraulic motor, and deceleration is performed with a constant braking torque that is only an electric motor. ing.

  FIG. 4 is an example showing the electrical characteristics of the electric double layer capacitor described in Non-Patent Document 1 depending on the voltage application conditions.

  According to FIG. 4, compared to the rated voltage (set voltage (Vset) in the present invention) of 5.5 volts, the applied voltage (corresponding to the set voltage (Vset) in the present invention) is compared between 5 volts and 4 volts. Looking at it, it is about 3,000 hours up to -40% at 5 volts, but about 6,000 hours at 4 volts, and it can be seen that the life to -40% is about twice longer at 4 volts. .

  The present invention proposes an unprecedented control method for a power storage device having such characteristics, and by adopting a control method for keeping the set voltage of the power storage device according to the present invention low according to the deterioration state. The life of the power storage device can be greatly extended by reducing the deterioration as compared with the conventional case.

  In addition, although the Example which applies the hybrid type construction machine control method which concerns on this invention to a construction machine was shown especially, the hybrid type operation | work using storage batteries, such as working machines, such as not only a construction machine but a hybrid type agricultural machine It goes without saying that it can be widely applied to machines.

ECU Electric control unit Em Electric motor Hm Hydraulic motor EG Engine T Hydraulic oil tank 10 Upper turning body 11 Deceleration unit 12 Inverter 13 Gear unit 14 Power storage device 16 Hydraulic motor unit 18 Communication valve 20 Switching valve 22 Hydraulic pump 24 Analog / digital conversion unit 26 Data memory 28 Central processing unit (CPU)
30 Digital / analog converter

Claims (4)

In a hybrid construction machine control method for controlling a set voltage (Vset) of a power storage device in a hybrid construction machine that cooperatively drives an electric motor supplied with power from the power storage device when driving a hydraulic actuator,
Wherein the voltage variation of the actual voltage (V o) in the actual voltage measured initial state with no degradation in the hybrid type construction machine of the electric storage device, since the voltage variation of said actual voltage after operation (Vac t) , Pm is the motor output, and f (Pm) and f ′ (Pm) are both functions with Pm as a dependent variable ,
Vo = f (Pm)
Vact = f ′ (Pm)
And the deterioration rate (K) defined by the following equation:
K = Vact / Vo
In addition ,
A function g (K) having K as a dependent variable, and a function g (K) defined by an approximate curve from operation test data of a hybrid type construction machine, or an adjustment coefficient (α) and a voltage deterioration rate (K) ,
α = g (K)
Using the function g (K) given by the two-dimensional matrix table of the adjustment coefficient (α) and the voltage deterioration rate (K)
From the rated voltage (Vb) of the power storage device and the adjustment coefficient (α) ,
Vset = α × Vb
A hybrid construction machine control method for calculating a new set voltage by   When the minimum actual voltage due to voltage fluctuations below the set voltage is below the lower voltage limit required for operation as the rated voltage set as the specification, an adjustment factor is calculated so that the minimum actual voltage exceeds the lower voltage limit. The hybrid construction machine control method according to claim 1, characterized in that:   When the maximum actual voltage due to voltage fluctuations below the set voltage exceeds the upper voltage limit necessary for operation as the rated voltage set as the specification, the adjustment factor is calculated so that the maximum actual voltage falls below the upper voltage limit. The hybrid construction machine control method according to claim 1, characterized in that: In the hybrid construction machine that controls the set voltage (Vset) of the power storage device by cooperatively driving the electric motor supplied with power from the power storage device when driving the hydraulic actuator,
Wherein the voltage variation of the actual voltage (V o) in the actual voltage measured initial state with no degradation in the hybrid type construction machine of the electric storage device, since the voltage variation of said actual voltage after operation (Vac t) , Pm is the motor output, and f (Pm) and f ′ (Pm) are both functions with Pm as a dependent variable ,
Vo = f (Pm)
Vact = f ′ (Pm)
And the deterioration rate (K) defined by the following equation:
K = Vact / Vo
In addition ,
A function g (K) having K as a dependent variable, and a function g (K) defined by an approximate curve from operation test data of a hybrid type construction machine, or an adjustment coefficient (α) and a voltage deterioration rate (K) ,
α = g (K)
Using the function g (K) given by the two-dimensional matrix table of the adjustment coefficient (α) and the voltage deterioration rate (K)
From the rated voltage (Vb) of the power storage device and the adjustment coefficient (α) ,
Vset = α × Vb
A hybrid construction machine that calculates a new set voltage.

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