JP2008044410A - Drive system of electrically driven dump truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the fuel consumption of a drive system of an electrically driven dump truck by automatically reducing the number of rotation of a motor if the load on the motor is low. <P>SOLUTION: Electric motors 12R, 12L are controlled based on the amount (p) of operation on an accelerator pedal 1. Also, a rotation number deviation ΔN is computed by subtracting from the actual number Ne of rotation of the motor 4 a target number Nr of rotation of the motor at that time. Based on the amount of operation on the accelerator pedal 1, the initial target number Nmin or Nmax of rotation of the motor is determined. The initial target number of rotation is set as the target number Nr of rotation of the motor. If the rotation number deviation ΔN is greater than a first set value ΔN1, the target number Nr of rotation of the motor 4 is gradually decreased; once the rotation number deviation ΔN becomes smaller than a second set value ΔN2, the target number Nr of rotation of the motor 4 is increased. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive system for an electrically driven dump truck, and more particularly, to a drive system for a large dump truck that travels by driving a generator with a prime mover, driving an electric motor for traveling with electric power generated by the generator.

  An electric drive dump truck drive system includes, for example, a motor, an electronic governor that controls the rotational speed and torque of the motor, an AC generator driven by the motor, and the AC generator as disclosed in Patent Document 1 For example, two electric motors that drive the left and right rear wheels, two inverters that are connected to an AC generator and control two electric motors (for example, induction motors), and an accelerator A control device that calculates a target rotation speed according to the operation amount of the pedal, controls the electronic governor, controls two inverters according to the operation amount of the accelerator pedal, and controls each electric motor; .

JP 2001-107762 A

  As described in Patent Document 1, in a conventional electrically driven dump truck, a target rotational speed is calculated according to an operation amount of an accelerator pedal, and a prime mover is driven at the target rotational speed. As a result, if the accelerator pedal is fully depressed, the prime mover will operate at the speed corresponding to the accelerator pedal, even if only a light load is loaded or the inclination is gentle and the load on the engine is small. , You will waste fuel.

  An object of the present invention is to provide a drive system for an electrically driven dump truck that can automatically reduce the rotational speed of the prime mover and reduce fuel consumption when the prime mover load is light.

  (1) In order to achieve the above object, the present invention provides a motor, an electronic governor for controlling the rotational speed and torque of the motor, an AC generator driven by the motor, and the motor driven by the motor. In an electric drive dump truck drive system having a prime mover load other than an alternator and at least two electric motors for driving driven by power supplied from the alternator, an accelerator pedal and an operation of the accelerator pedal Motor control means for controlling the electric motor based on the amount; and prime mover control means for controlling the prime mover by controlling the electronic governor, wherein the prime mover control means determines the prime mover from the actual rotational speed of the prime mover. A first means for calculating a rotational speed deviation obtained by subtracting the target rotational speed at the time, and the prime mover based on the operation amount of the accelerator pedal A second means for obtaining an initial target rotational speed and setting the initial target rotational speed as a target rotational speed of the prime mover; and when the rotational speed deviation is greater than a first set value, the target rotational speed of the prime mover is gradually decreased And a third means.

  In the present invention configured as described above, when the accelerator pedal is operated, the second means sets the target rotational speed of the prime mover based on the initial target rotational speed corresponding to the operation amount of the accelerator pedal, and then the load on the prime mover is large. When the target rotational speed is maintained, the load is light, and the rotational speed deviation calculated by the first means becomes larger than the first set value, the third means gradually decreases the target rotational speed. As a result, when the load is too light, the rotational speed of the prime mover can be automatically reduced to reduce the fuel consumption.

  (2) In the above (1), preferably, when the third means gradually decreases the target rotational speed of the prime mover, the rotational speed deviation is smaller than the first set value, and from the first set value, When it becomes larger than the small second set value, the target rotational speed at that time is maintained, and when the rotational speed deviation becomes smaller than the second set value, the target rotational speed of the prime mover is increased.

  As a result, when the target rotational speed is lowered and the rotational speed deviation becomes a value between the first set value and the second set value, the target rotational speed at that time is maintained and the rotational speed deviation is less than the second set value. When it becomes smaller, the target rotational speed increases, so the rotational speed of the prime mover automatically increases.

  (3) In the above (1), preferably, when the third means gradually decreases the target rotational speed, if the target rotational speed decreases to an intermediate rotational speed higher than a minimum rotational speed, the target rotational speed is reduced. It further has 4th means hold | maintained at the said intermediate rotation speed.

  As a result, when the state in which the rotational speed deviation is larger than the second set value continues, the target rotational speed is reduced to the intermediate rotational speed, and the rotational speed of the prime mover is similarly reduced. Thereafter, when the load increases and the rotational speed deviation becomes smaller than the second set value, the target rotational speed automatically increases from the intermediate rotational speed.

  (4) In the above (1), preferably, when the third means gradually decreases the target rotational speed, the target rotational speed is set to the initial target as soon as the rotational speed deviation becomes smaller than a second set value. Return to speed.

  As a result, after the number of revolutions of the prime mover decreases, when the load increases, the number of revolutions of the prime mover immediately increases to the number of revolutions corresponding to the amount of operation of the accelerator pedal, so that the number of revolutions can be increased with good response.

  (5) In the above (1), when the third means gradually decreases the target rotational speed, the target rotational speed is increased to the maximum rotational speed as soon as the rotational speed deviation becomes smaller than the first set value. You may let them.

  Also in this case, since the rotational speed of the prime mover increases to the maximum rotational speed as soon as the load increases after the rotational speed of the prime mover decreases, the rotational speed can be increased with good response.

  (6) In the above (1), preferably, when the accelerator pedal is not operated, the second means sets a minimum rotational speed as the initial target rotational speed, and the accelerator pedal is operated. Then, the maximum rotational speed is set as the initial target rotational speed.

  (7) Further, in the above (1), preferably, when the accelerator pedal is not operated, the second means sets a minimum rotational speed as the initial target rotational speed, and the accelerator pedal is operated. Then, the rotation speed according to the operation amount of the accelerator pedal is set as the initial target rotation speed.

  According to the present invention, in the electric drive dump truck, when the prime mover load is light, the number of revolutions of the prime mover can be automatically reduced to reduce the fuel consumption.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of an electric drive dump truck drive system according to a first embodiment of the present invention.

  In FIG. 1, the drive system of the electrically driven dump truck includes an accelerator pedal 1, a retard pedal 2, a shift lever 16, an overall control device 3, a prime mover 4, an AC generator 5, other prime mover loads 18, a rectifier circuit 6, and an inverter control. A device 7, a chopper circuit 8, a grid resistor 9, a capacitor 10, a resistor 11, left and right electric motors (for example, induction motors) 12R and 12L, speed reducers 13R and 13L, tires 14R and 14L, and electromagnetic pickup sensors 15R and 15L are provided. Yes. The inverter control device 7 includes torque command calculation units 71R and 71L, motor control calculation units 72R and 72L, and inverters (switching elements) 73R and 73L for the left and right electric motors 12R and 12L, respectively.

  The operation signal p of the accelerator pedal 1 and the operation signal q of the retard pedal 2 are input to the overall control device 3, and are signals for controlling the magnitudes of the driving force and the retarding force, respectively.

  When the dump truck is moved forward or backward, when the accelerator pedal 1 is depressed with the shift lever 16 in the forward position or the reverse position, the overall control device 3 outputs a command for the target rotational speed Nr to the prime mover 4. On the side, the actual rotational speed Ne is detected by a rotational speed sensor (not shown), and the signal is returned from the prime mover 4 to the control device 3. The prime mover 4 is a diesel engine equipped with an electronic governor 4a. When the electronic governor 4a receives a command for the target rotational speed Nr, it controls the fuel injection amount so that the prime mover 4 rotates at the target rotational speed Nr.

  An AC generator 5 is connected to the prime mover 4 and performs AC generation. The electric power generated by the AC power generation is rectified by the rectifier circuit 6 and stored in the capacitor 10, and the DC voltage value becomes V. The AC generator 5 is controlled by the overall controller 3 so that the voltage value obtained by dividing the DC voltage V by the detection resistor 11 is fed back and the voltage value becomes a predetermined constant voltage V0.

  The electric power generated by the AC generator 5 is supplied to the left and right electric motors 12R and 12L via the inverter control device 7. The overall control device 3 controls the AC generator 5 so that the DC voltage V rectified by the rectifier circuit 6 becomes a predetermined constant voltage V0, so that necessary electric power is supplied to the electric motors 12R and 12L. I have control.

  The command horsepower MR, ML of the left and right electric motors 12R, 12L from the overall control device 3 and the rotational speeds ωR, ωL of the electric motors 12R, 12L detected by the electromagnetic pickups 15R, 15L are input to the inverter control device 7. The inverter control device 7 drives the electric motors 12R and 12L with a slip ratio> 0 via the torque command calculation units 71R and 71L, the motor control calculation units 72R and 72L, and the inverters (switching elements) 73R and 73L.

  Left and right rear wheels (tires) 14R and 14L are connected to the electric motors 12R and 12L via speed reducers 13R and 13L, respectively. The electromagnetic pickups 15R and 15L are usually sensors that detect the peripheral speed of one tooth of a gear in the speed reducers 13R and 13L. Further, for example, taking the right drive system as an example, a detection gear may be attached to the drive shaft inside the electric motor 12R or the drive shaft connecting the speed reducer 13R and the tire 14R and installed at that position.

  When the accelerator pedal 1 is returned and the retard pedal 2 is depressed during traveling, the overall control device 3 controls so that the AC generator 5 does not generate power. Further, the horsepower commands MR and ML from the overall control device 3 have negative values, and the inverter control device 7 applies braking force to the vehicle body that travels by driving the electric motors 12R and 12L with a slip ratio <0. At this time, each of the electric motors 12R and 12L acts as a generator, and works to charge the capacitor 10 by a rectification function built in the inverter control device 7. The chopper circuit 8 operates so that the DC voltage value V is equal to or less than a preset DC voltage value V1, and current is passed through the grid resistor 9 to convert electrical energy into heat energy.

  In addition to the alternator 5, the prime mover 4 includes a hydraulic pump 18a (hereinafter referred to as a working hydraulic pump) 18a for driving the hydraulic system for raising and lowering the vessel of the dump truck and steering operation, and a radiator. A cooling fan (not shown) for blowing air, a second fan (not shown) for driving an electric fan (not shown) for cooling the AC generator 5, the grid resistor 9, the electric motors 12R and 12L, the control devices 3 and 7, and the like. A generator is driven. In FIG. 1, these are shown as other prime mover loads 18.

  The above is the basic configuration and operation of a normal electric drive dump truck.

  Here, the torque characteristics of the prime mover 4 will be described. FIG. 2 is a diagram showing the relationship between the rotational speed Ne (actual rotational speed) of the prime mover 4 and the output torque Te. FIG. 3 is a diagram showing the fuel injection characteristics of the electronic governor 4a.

  The electronic governor 4a of the prime mover 4 of the present embodiment has all the target rotational speeds including when the target rotational speed Nr is equal to the maximum rotational speed (rated rotational speed) Nrmax, that is, when Nr = Nrmax (for example, 2000 rpm). In the range, the fuel injection amount control is set to be droop control.

  In FIG. 2, straight lines R1 and R2 are torque characteristics of the motor 4 in the control region of the electronic governor 4a, a straight line R1 is a droop control characteristic at Nr = Nrmax, and a straight line R2 is a droop control characteristic at Nr = Nrmid (<Nmax). It is a characteristic.

  It is assumed that Nr = Nrmax and the motor 4 is operating at point A on the straight line R1 in the area Y0. When the load applied to the prime mover 4 increases from this state, the electronic governor 4a increases the injected fuel accordingly and increases the output torque. When the output torque of the prime mover 4 reaches a predetermined magnitude, for example, balance occurs at the point B. . Furthermore, when the prime mover load increases, the point Y is reached. Point Y is a state in which the fuel injection amount is maximized, and the output torque of the prime mover 4 cannot be increased any further. Furthermore, when the load applied to the prime mover 4 increases, the point C in the region Y1 is reached, eventually causing a stall and an engine stall. Thus, the region Y0 (control region of the electronic governor 4a) indicates a state where the output of the prime mover 4 has a margin, and the region Y1 (outside the control region of the electronic governor 4a) indicates a state where the output of the prime mover 4 has no margin. .

  The straight line R1 of the droop control has a predetermined slope, and on this straight line R1, the electronic governor 4a controls the fuel injection amount so as to increase the output torque while decreasing the rotational speed Ne of the prime mover.

  The same applies to the straight line R2 of the droop control. On the straight line R2, the electronic governor 4a controls the fuel injection amount so as to increase the output torque while decreasing the rotational speed Ne of the prime mover.

  When the droop control is performed with Nr = Nrmax, the electronic governor 4a is fueled so that ΔN (= Ne−Nr) becomes zero due to the rotational speed deviation ΔN which is the deviation between the target rotational speed Nr and the actual rotational speed Ne. Control the injection amount. FIG. 3 shows the relationship between the rotational speed deviation ΔN and the fuel injection amount Q at that time, and points A1, B1, Y1, and C1 are points A, B, Y, Corresponds to point C. As the load torque of the electric motors 12R, 12L increases and the rotational speed deviation ΔN (> 0) decreases, the fuel injection amount increases from A1 point → B1 point → Y1 point. The operating point changes from point A to point B to point Y. Since the fuel injection amount does not increase beyond the Y1 point, if the load on the prime mover 4 further increases, the operating point changes from the Y point to the C point. If the load further increases from this state, a stall will occur.

  The same applies when droop control is performed with Nr = Nrmid.

  Next, the part which becomes the characteristic of this invention is demonstrated.

  In the present invention, the operation of each component device is calculated according to a processing procedure in a memory (not shown) incorporated in the overall control device 3 and the inverter control device 7, respectively. FIG. 4 is a functional block diagram showing the processing procedure, and FIGS. 5 and 6 are flowcharts showing the processing procedure. In the following, the processing procedure will be described mainly using the functional block diagram of FIG. 4 according to the flowcharts shown in FIGS.

  In FIG. 5 and FIG. 6, the processing starts from START, and when processing up to END, the processing flow returns to START again.

  In step 101, the state quantity S indicating the switching position of the shift lever 16, the operation amount of the accelerator pedal 1 (hereinafter referred to as the accelerator operation amount) p, the current target rotational speed Nr of the prime mover 4, the actual rotational speed Ne of the prime mover 4, travel The rotational speeds (hereinafter referred to as motor rotational speeds) ωR, ωL of the electric motors 12R, 12L are read. There are three positions for switching the shift lever 16: N (neutral), F (forward), and R (reverse).

  In step 102, the target rotational speed automatic increase / decrease process is performed based on the accelerator operation amount p read in step 101, the current target rotational speed Nr and the actual rotational speed Ne of the prime mover 4, and a new target rotational speed Nr is calculated ( FIG. 4 block 202). Details of the target rotation speed automatic increase / decrease process will be described later.

  In step 111, the actual rotational speed Ne of the prime mover 4 read in step 101 is referred to a data map of engine rotational speed vs. motor maximum output horsepower represented by the motor maximum output horsepower function Mr (Ne) shown in FIG. Then, the corresponding maximum horsepower Mr that can be used by the electric motors 12R and 12L is calculated, and this is multiplied by ½ to calculate the output horsepower upper limit value Pmax per electric motor 12R and 12L (see FIG. 4). Blocks 211, 212).

  In FIG. 7, the function Mr (Ne) is the maximum horsepower (hereinafter referred to as motor maximum output horsepower) Mr that can be used by the electric motors 12R and 12L as the actual rotational speed Ne (hereinafter referred to as engine speed) Ne of the prime mover 4 increases. Is set to increase.

  A method for setting the function Mr (Ne) of the motor maximum output horsepower will be described.

  FIG. 8 is a diagram showing a data map of rotational speed versus prime mover maximum output horsepower represented by a function f (Ne) and a data map of rotational speed versus other prime mover load loss horsepower represented by a function g (Ne). .

  The function f (Ne) is the maximum output horsepower that the motor 4 can output, and is a synthesis of the function f1 (Ne), the function f2 (Ne), and the function f3 (Ne). The function f1 (Ne) corresponds to the function fr = f (Nr) of the target rotational speed Nr of the prime mover 4 and the output horsepower, and the engine rotational speed Ne changes from Nrmin (for example, 750 rpm) to Nrmax (for example, 2000 rpm). Then, the maximum output horsepower f (Ne) that the motor 4 can output changes from the minimum value Fmin to the maximum value Fmax. This is a characteristic diagram specific to the prime mover 4. The function f2 (Ne) is obtained by setting the maximum output horsepower f (Ne) of the prime mover 4 to a constant value of f2 = Fmin in the range of 0 ≦ Ne <Nrmin, and the function f3 (Ne) is Nrmax <Ne ≦ In the range of Nemax, the maximum output horsepower f (Ne) of the prime mover 4 is a constant value of f3 = Fmax.

  The prime mover 4 drives other prime mover loads 18 in addition to the AC generator 5. The other prime mover load 18 includes a hydraulic pump 18a for driving a hydraulic system for raising and lowering the vessel of the dump truck and a steering operation, a cooling fan (not shown) for blowing air to the radiator, the AC generator 5, A second generator (not shown) for driving an electric fan (not shown) for cooling the grid resistor 9, the electric motors 12R and 12L, the control devices 3 and 7, and the like. The horsepower value assigned in advance for driving the other prime mover load 18 is g (Ne) in FIG. This horsepower g (Ne) is set large with a margin with respect to the horsepower value actually consumed by the other prime mover load 18. In the present specification, this horsepower is referred to as lost horsepower.

  The loss horsepower function g (Ne) is a combination of the function g1 (Ne), the function g2 (Ne), and the function g3 (Ne), like the function (Ne). In the function g1 (Nr), when the engine speed Ne changes from Nrmin (for example, 750 rpm) to Nrmax (for example, 2000 rpm), the loss horsepower g1 (Ne) changes from the minimum value Gmin to the maximum value Gmax. The function g2 (Ne) is obtained by setting the loss horsepower g (Ne) to a constant value of g2 = Gmin in the range of 0 ≦ Ne <Nrmin, and the function g3 (Ne) is in the range of Nrmax <Ne ≦ Nemin. The loss horsepower g (Ne) is a constant value of g3 = Gmax.

  In FIG. 8, Mr, which is the difference between f (Ne) and g (Ne) (f (Ne) -g (Ne)), is the total effective maximum horsepower that may be given to the electric motors 12R, 12L. In other words, Mr = f (Ne) −g (Ne) is the maximum horsepower (assigned value of horsepower) that can be used by the electric motors 12R and 12L for traveling out of the maximum output horsepower f (Ne) that the prime mover 4 can output. The maximum output horsepower of the electric motors 12R and 12L cannot exceed the value, that is, Mr = f (Ne) −g (Ne).

  The function Mr (Ne) of the motor maximum output horsepower is set based on the above-described idea, and the output horsepower upper limit value Pmax per one of the electric motors 12R, 12L is given by the following equation.

Pmax = Mr / 2 = (f (Ne) -g (Ne)) / 2
In step 112, the accelerator operation amount p read in step 101 is converted into a data map of accelerator operation amount versus motor target output horsepower represented by the function Pm1 (p) of the first motor target output horsepower at the time of forward movement shown in FIG. Referring to FIG. 4, the corresponding first motor target output horsepower Pm1 is calculated (block 213 in FIG. 4).

  In FIG. 9, the function Pm1 (p) is the first motor target output horsepower Pm1 = 0 when the accelerator operation amount is p = 0, and is slightly depressed, that is, Pm1 increases from the point X1 in FIG. The rate of increase in Pm1 is increased so that the accelerator operation amount becomes the maximum horsepower Pm1max that can be generated by the electric motors 12R and 12L at the point X3 before the maximum value pmax. The accelerator operation amount px3 at the point X3 in FIG. 9 is, for example, about 95% of the maximum operation amount pmax.

  In step 113, the accelerator operation amount p read in step 101 is converted into a data map of accelerator operation amount versus motor target output horsepower represented by a function Pm2 (p) of the second motor target output horsepower during reverse travel shown in FIG. Referring to FIG. 4, the corresponding second motor target output horsepower Pm2 is calculated (block 214 in FIG. 4).

  In FIG. 10, the function Pm2 (p) indicates that the second motor target output horsepower Pm2 increases as the accelerator operation amount p increases. The maximum value Pm2max of the second motor target output horsepower is a forward function Pm1 (p). Is set to be smaller than the maximum value Pm1max. The reverse motor target output horsepower may be obtained by multiplying the motor target output horsepower obtained by the forward function Pm1 (p) by a positive constant smaller than 1.

  In steps 114 to 117, if the state quantity S of the shift lever 16 read in step 101 is N (neutral), the target horsepower (hereinafter referred to as motor target output horsepower) Pm0 of the electric motors 12R and 12L is set as Pm0 = 0. If the state quantity S of the shift lever 16 is F (forward), the target horsepower (hereinafter referred to as motor target output horsepower) Pm0 of the electric motors 12R and 12L is set as Pm0 = Pm1, and the state quantity S of the shift lever 16 is R. If (reverse), the motor target output horsepower Pm0 is set as Pm0 = Pm2 (blocks 215 and 216 in FIG. 4).

  In step 118, the smaller value of the motor output horsepower upper limit value Pmax and the motor target output horsepower Pm0 is selected and set as the motor output target horsepower Pm (block 217 in FIG. 4).

Pm = min (Pmax, Pm0)
That is, in step 118 (block 217 in FIG. 4), the final motor output target horsepower Pm given to the electric motors 12R and 12L is limited so as not to exceed Pmax. The motor output target horsepower Pm corresponds to the command horsepower MR and ML shown in FIG. 1 (MR = ML = Pm).

  In step 121, motor target torques Tr1R and Tr1L are calculated from the motor output target horsepower Pm and the rotational speeds ωR and ωL of the electric motors 12R and 12L read in step 101 by the following formula (blocks 221 and 222 in FIG. 4). ).

Tr1R = K1 × Pm / ωR
Tr1L = K1 × Pm / ωL
K1: Constant for calculating torque from horsepower and rotation speed.

  FIG. 11 is a diagram showing the relationship between the motor output target horsepower Pm, the rotational speeds ωR, ωL of the electric motors 12R, 12L, and the motor target torques Tr1R, Tr1L. When the motor output target horsepower Pm is determined, motor target torques Tr1R and Tr1L corresponding to the motor rotation speeds ωR and ωL at that time are determined. For example, when the motor rotation speeds ωR and ωL are ω1, the motor target torque is Tr1R = Pm (ω1) and Tr1L = Pm (ω1). Further, for example, when the load torque of the electric motors 12R and 12L increases due to the dump truck reaching a slope and the motor rotation speeds ωR and ωL decrease, the motor target torques Tr1R and Tr1L increase accordingly. Conversely, when the motor load torque decreases, the motor target torques Tr1R and Tr1L are decreased. On the other hand, if the motor output target horsepower Pm increases, the motor target torques Tr1R, Tr1L increase accordingly. If the motor load torque at that time is constant, the motor rotational speeds ωR, ωL increase. Conversely, when the motor output target horsepower Pm decreases, the motor rotational speeds ωR and ωL decrease if the motor load torque is constant.

  In step 122, the rotational speeds ωR and ωL of the electric motors 12R and 12L read in step 101 are represented by the motor maximum speed / motor maximum torque data map represented by the motor maximum torque function Trmax1 (ω) shown in FIG. Referring to FIG. 4, the corresponding maximum motor torque Trmax1 is calculated (blocks 223 and 224 in FIG. 4).

  In FIG. 12, the function Trmax1 (ω) indicates the maximum current value that the inverters 72R and 72L can flow to the electric motors 12R and 12L, the output limit of driving elements such as IGBT and GTO in the inverters 72R and 72L, and the strength of each motor shaft. And so on, based on the specifications of the devices constituting the drive system. As shown in FIG. 12, for example, when the motor rotation speeds ωR and ωL are ω1, the motor maximum torque Trmax1 is Trmax1 (ω1). The maximum value of the motor maximum torque Trmax1 is Trmax.

In step 124, the motor target torques Tr1R and Tr1L obtained in step 121 are compared with the motor maximum torque Trmax1 obtained in step 122, and the minimum value thereof is selected as motor torque command values TrR and TrL ( Blocks 226, 227 of FIG. That is,
TrR = min (Tr1R, Trmax1)
TrL = min (Tr1L, Trmax1)
In step 125, the engine target speed Nr obtained in step 102 is commanded to the electronic governor 4a of the prime mover 4.

  In step 126, the motor control command units TrR and TrL obtained in step 123 are commanded to the inverters 73R and 73L by the motor control calculation units 72R and 72L in the inverter control device 7, and torque control of the electric motors 12R and 12L is performed. The

  The processes of procedures 101 to 118 (blocks 201 to 217 in FIG. 4) and the process of procedure 125 are processes performed by the overall control device 3, and procedures 121, 122, and 124 (blocks 221 to 224, block 226 in FIG. 4) are performed. 227) and the process of the procedure 126 are processes performed by the torque command calculation units 71R and 71L of the inverter control device 7.

  Details of the target rotation speed automatic increase / decrease process performed in the procedure 102 (block 202 in FIG. 4) will be described with reference to FIGS.

  FIG. 13 is a flowchart showing the entire target rotational speed automatic increase / decrease process. The process of FIG. 13 is executed every 10 ms, for example. 13, in step 201, the operation amount (accelerator operation amount) p of the accelerator pedal 1, the current target rotational speed Nr of the prime mover 4, and the actual rotational speed Ne of the prime mover 4 are read. The procedure 201 is a reprint of part of the processing of the procedure 101 shown in FIG.

In step 202, the actual rotational speed Ne is subtracted from the target rotational speed Nr of the prime mover 4 based on the current target rotational speed Nr and the actual rotational speed Ne of the prime mover 4 read in the procedure 201, and the rotational speed deviation ΔN is calculated. . That is,
ΔN = Ne−Nr
In step 203, the current state flag C is read. The following three types are registered in the current status flag C.

C = I: Idle state C = M: Maximum rotational speed state C = A: Automatic decrease state In steps 204 to 206, mode control according to the current state flag C is performed. That is, if C = I, idle mode control is performed (procedure 204), if C = M, maximum speed mode control is performed (procedure 205), and if C = A, automatic decrease mode control is performed (procedure 204). 206).

  Details of the three types of mode control will be described with reference to FIGS.

  FIG. 14 is a flowchart showing details of the idle mode control, FIG. 15 is a diagram showing the target rotational speed Nr according to the accelerator operation amount p set in the idle mode control, and FIG. 16 shows the maximum rotational speed mode control. FIG. 17 is a flowchart showing details of automatic reduction mode control.

  In FIG. 14 showing the idle mode control, first, in step 211, it is determined whether or not the accelerator operation amount p is smaller than the set value p0. If yes (p <p0), the minimum target rotation speed Nr is determined in step 212. A rotational speed (idle rotational speed) Nmin is set (Nr = Nmin). If no (p ≧ p0), the maximum rotational speed Nmax is set as the target rotational speed Nr in step 214 (Nr = Nmax). Thus, in steps 212 and 214, a target rotational speed Nr as shown in FIG. 15 is set according to the accelerator operation amount p. The set value p0 is, for example, an operation amount that is about 5% of the maximum operation amount. Further, the minimum rotation speed Nmin is, for example, 750 rpm, and the maximum rotation speed Nmax is, for example, 2000 rpm.

  When the minimum rotational speed Nmin is set as the target rotational speed Nr in the procedure 212, the count value of the timer 1 is cleared in the procedure 213 (timer 1 = 0), and then the procedure returns to the start and the above procedure is repeated. When the maximum rotational speed Nmax is set as the target rotational speed Nr in the procedure 214, the status flag C is set to M (maximum rotational speed state) in the procedure 215 (C = M), and then the procedure returns to the start and the procedure described above. repeat.

  In FIG. 16 showing the maximum rotational speed mode control, in step 221, it is determined whether the rotational speed deviation ΔN is larger than the set value ΔN1, and if yes (ΔN> ΔN1), the timer 1 is counted up in step 222, If no (ΔN ≦ ΔN1), the process returns to the start and the above procedure is repeated. After counting up timer 1 in step 222, it is determined in step 223 whether the count value of timer 1 has reached the set value N1. If no, the procedure returns to the start and the above procedure is repeated. At 224, the state flag C is set to A (automatic decrease state) (C = A), the count value of timer 1 is cleared at step 225 (timer 1 = 0), and the above procedure is repeated after returning to the start. The set value ΔN1 is, for example, +5 rpm, and the set value N1 is a count value corresponding to, for example, 2 to 3 seconds. If the calculation cycle is 10 ms, for example, the count value corresponding to 3 seconds is 300.

  In FIG. 17 showing the automatic reduction mode control, in step 231, it is determined whether or not the rotational speed deviation ΔN is larger than the set value ΔN1, and if yes (ΔN> ΔN1), in step 232, the target rotational speed Nr at that time is determined. Is subtracted from the predetermined value δN to obtain a new target rotational speed Nr (Nr = Nr−δN). In step 233, it is determined whether or not the new target rotational speed Nr has reached the intermediate rotational speed Nmid. If (Nr> Nmid), the process returns to the start and the above procedure is repeated. If yes (Nr = Nmid), the target rotational speed Nr is maintained at the intermediate rotational speed Nmid (Nr = Nmid) in step 234. Here, the predetermined value δN is, for example, 0.1 rpm for a calculation cycle of 10 ms. Further, as shown in FIG. 15, the intermediate rotational speed Nmid is a rotational speed near the middle between the minimum rotational speed (idle rotational speed) Nmin and the maximum rotational speed Nmax, and is, for example, 1500 rpm.

  If the predetermined value δN is, for example, 0.1 rpm for a calculation cycle of 10 ms, in procedure 232, 0.1 rpm is subtracted from the target rotational speed Nr for each calculation cycle. In this case, when the reduction rate of the target rotational speed is converted to 1 second, it is 10 rpm / 1 sec. As a result of performing a test by applying a load to the prime mover or reducing the accelerator operation in advance, it took about 2 seconds (2000 ms) to decrease by 1000 rpm. In this case, the reduction rate of the motor speed is 5 rpm / 10 ms. When ΔN> ΔN1 and timer 1 = N1, if the target rotational speed Nr is decreased faster than the rate of decrease, the engine rotational speed will increase and decrease repeatedly even though there is not much load fluctuation. . In order to avoid such a phenomenon, it is preferable to set the predetermined value δN so as to decrease slowly at 1/3 to 1/100 of the decrease rate of 5 rpm / 10 ms. By setting the predetermined value δN to 0.1 rpm for a calculation cycle of 10 ms, the decrease rate of the target rotation speed Nr becomes 1/50 of the decrease rate of 5 rpm / 10 ms, and without repeating the increase and decrease of the engine rotation speed, The engine speed can be reduced stably.

  If the determination in step 231 is no (ΔN ≦ ΔN1), it is determined in step 235 whether the rotational speed deviation ΔN is larger than the set value ΔN2, and if yes (ΔN> ΔN2), in step 236, The target rotational speed Nr is maintained at the target rotational speed Nr at that time (Nr = Nr). Here, the set value ΔN2 is smaller than the set value ΔN1 (ΔN2 <ΔN1). When the set value ΔN1 is, for example, +5 rpm, the set value ΔN2 is, for example, −20 rpm. If the determination in step 235 is no (ΔN ≦ ΔN1), in step 237, the state flag C is set to M (maximum rotational speed state) (C = M), the process returns to the start and the above procedure is repeated.

  In the above, the processing of procedures 101, 111 to 124, 126 (blocks 211 to 224 in FIG. 4) in FIGS. 5 and 6 is performed by motor control for controlling the electric motors 12R and 12L based on the operation amount p of the accelerator pedal 1. The processing of steps 101, 102, and 125 (block 202 in FIG. 4) constitutes a motor control unit that controls the electronic governor 4a and controls the motor 4.

  Further, the process of the procedure 202 in FIG. 13 constitutes a first means for calculating a rotational speed deviation ΔN obtained by subtracting the target rotational speed Nr of the prime mover from the actual rotational speed Ne of the prime mover 4, and the procedure 203 in FIG. 204 and steps 211 to 215 in FIG. 14 obtain the initial target rotational speed Nmin or Nmax of the prime mover based on the operation amount of the accelerator pedal 1, and set this initial target rotational speed as the target rotational speed Nr of the prime mover. The second means constitutes the steps 203, 205 and 206 in FIG. 13, the steps 221 to 225 in FIG. 16, and the steps 231 and 232 in FIG. 17, when the rotational speed deviation ΔN is larger than the first set value ΔN1. A third means for gradually decreasing the target rotational speed Nr of the prime mover 4 is configured.

  Further, in the processes in steps 203 and 206 in FIG. 13 and steps 235 to 237 in FIG. 17, when the third means gradually decreases the target rotational speed Nr of the prime mover 4, the rotational speed deviation ΔN is set to the first setting. When it is smaller than the value ΔN1 and larger than the second set value ΔN2 smaller than the first set value ΔN1, the target rotational speed Nr at that time is maintained, and when the rotational speed deviation ΔN becomes smaller than the second set value ΔN2, the target of the motor 4 The rotational speed Nr is increased.

  The processes in steps 203 and 206 in FIG. 13 and steps 233 and 234 in FIG. 17 are intermediate steps in which the target speed Nr is higher than the minimum speed Nmin when the third means gradually decreases the target speed Nr of the prime mover 4. When the rotational speed is reduced to Nmid, fourth means for maintaining the target rotational speed Nr at the intermediate rotational speed Nmid is configured.

  Next, the operation of the present embodiment will be described.

  As described above, in step 111 in FIG. 5 (blocks 211 and 212 in FIG. 4), the electric motors 12R and 12L refer to the map of the function Mr (Ne) shown in FIG. The corresponding maximum horsepower Mr that can be used is calculated, and this is multiplied by 1/2 to calculate the output horsepower upper limit value Pmax per electric motor 12R, 12L. Further, in step 118 of FIG. 5 (block 217 of FIG. 4), by selecting the smaller value of the motor output horsepower upper limit value Pmax and the motor target output horsepower Pm0, the final value given to the electric motors 12R and 12L The motor output target horsepower Pm is limited so as not to exceed Pmax.

  The function Mr (Ne) is a difference (f (Ne) −g (Ne)) between the function f (Ne) and the function g (Ne).

  Here, the function f (Ne) is the maximum output horsepower that the prime mover 4 can output, and the function g (Ne) is a horsepower value (lost horsepower) assigned in advance to drive the other prime mover loads 18. This loss horsepower is a predicted value of horsepower consumed by the other prime mover load 18. For example, if the maximum output of the prime mover 4 at the rated rotational speed is 1500 kW and the consumed horsepower of the other prime mover load 18 is 50 to 200 kW, the estimated loss horsepower can be set to 200 kW and can be used by the prime mover 4 The maximum horsepower Mr is set to 1300 kW.

  In this case, since the motor is not driven when the vehicle is not traveling, the output horsepower of the prime mover 4 always has a margin, and the automatic target rotational speed increase / decrease process (block 202 in FIG. 4) of the prime mover 4 in the procedure 102 in FIG. Operation is performed at a lower target rotational speed.

  During traveling, even when the traveling motor is fully consuming the output horsepower of the upper limit value Pmax (Mr = 1300 kW), if the horsepower consumed by the other prime mover load 18 is less than 200 kW (for example, If there is only about 50 kW), the output horsepower of the prime mover 4 still has a margin, and an operation in which the target revolution number of the prime mover 4 is lowered by the automatic target revolution speed increase / decrease process of the procedure 102 in FIG. 5 (block 202 in FIG. 4). Done. Further, when the traveling horsepower consumed by the traveling motor is smaller than the output horsepower upper limit Pmax (Mr = 1300 kW), such as when traveling at a low speed on a flat road, the output horsepower of the prime mover 4 has a margin in the same manner. An operation is performed in which the target rotational speed of the prime mover 4 is reduced by the automatic target rotational speed increase / decrease process 102 (block 202 in FIG. 4).

  The operation during non-travel and during travel will be specifically described below.

1. When not traveling When not traveling, shift lever 16 is set to the N (neutral) position. When the shift lever 16 is set to the N (neutral) position, the target horsepower Pm0 of the electric motors 12R and 12L is Pm0 = 0, and the motor is not driven.

  On the prime mover side, the target rotational speed of the prime mover 4 is set by the automatic target rotational speed increase / decrease process of the procedure 102 of FIG. 5 (block 202 of FIG. 4), and the rotational speed of the prime mover 4 is set by the electronic governor 4a based on the target rotational speed. And the output torque is controlled.

  That is, when the accelerator pedal 1 is not depressed, the target rotational speed Nr of the prime mover 4 is 750 rp, which is the minimum rotational speed (idle rotational speed) Nmin (Nr = Nmin), and the fuel consumption can be minimized. .

  When the accelerator pedal 1 is depressed with the intention of stopping the dump truck and operating only the hydraulic system, the target rotational speed Nr of the prime mover 4 immediately becomes the maximum rotational speed Nmax (Nr = Nmax). The rotational speed of the prime mover 4 rises with good response up to the maximum rotational speed. For this reason, responsiveness when the accelerator pedal 1 is depressed is improved, and good workability can be obtained.

  In addition, since the motor is not driven and the output horsepower of the prime mover 4 has a margin, the rotational speed deviation ΔN becomes ΔN> ΔN1 in the automatic target rotational speed increase / decrease process of the procedure 102 in FIG. 5 (block 202 in FIG. 4). The target rotational speed Nr gradually decreases (procedures 231 and 232 in FIG. 17), and the rotational speed of the prime mover 4 also decreases accordingly. When the target rotational speed Nr decreases and the rotational speed deviation ΔN becomes ΔN2 <ΔN ≦ ΔN1, the target rotational speed Nr at that time is maintained (steps 235 and 236 in FIG. 17), and the prime mover 4 has the target rotational speed Nr. Be controlled. When the target rotational speed Nr further decreases to an intermediate rotational speed Nmid of 1500 rpm, the intermediate rotational speed Nmid is maintained (Nr = Nmid) (steps 233 and 234 in FIG. 17), and the prime mover 4 is controlled at the intermediate rotational speed. Is done.

  When the depression amount of the accelerator pedal 1 is returned to 0 (no operation), the target rotational speed Nr immediately becomes the minimum rotational speed Nmin of 750 rpm (Nr = Nmin), and the prime mover 4 is controlled to the idle rotational speed.

  In this way, when working by operating the hydraulic system only with the dump truck stopped, such as raising the vessel, the prime mover 4 has room, so the number of revolutions of the prime mover 4 is automatically reduced to reduce fuel consumption. can do.

2. During traveling For example, when the shift lever 16 is set to the F (forward) position, the function Pm1 (p) of the first motor target output horsepower during forward traveling shown in FIG. ) Is selected, the first motor target output horsepower Pm1 by the function Pm1 (p) is given as the motor target output horsepower Pm0, and the motor is driven based on the first motor target output horsepower Pm1 (motor target output horsepower Pm0). The motors 12R and 12L are controlled. As a result, it is possible to obtain a good operation feeling in which the relationship between the operation amount of the accelerator pedal 1 and the output horsepower of the electric motors 12R and 12L is the same.

  On the electric motor side, in step 111, the maximum horsepower Pmax that can be used by the electric motors 12R and 12L according to the number of revolutions of the prime mover 4 is calculated. In step 118, the motor target output horsepower Pm0 has the maximum horsepower Pmax. Limit not to exceed. As a result, even when the speed of the prime mover 4 is not sufficiently increased during acceleration at the start of traveling and the motor target output horsepower Pm0 exceeds the maximum horsepower Pmax, the motor target output horsepower Pm0 is limited to the maximum horsepower Pmax. Therefore, stalling of the prime mover 4 can be prevented.

  On the prime mover side, the target rotational speed of the prime mover 4 is set by the automatic target rotational speed increase / decrease process of the procedure 102 of FIG. 5 (block 202 of FIG. 4), and the rotational speed of the prime mover 4 is set by the electronic governor 4a based on the target rotational speed. And the output torque is controlled.

  That is, when the accelerator pedal 1 is depressed for the purpose of traveling, the target rotational speed Nr of the prime mover 4 immediately reaches the maximum rotational speed Nmax (Nr = Nmax), and the rotational speed of the prime mover 4 increases to the maximum rotational speed with good response. For this reason, the responsiveness when the accelerator pedal 1 is depressed is improved, and good acceleration performance can be obtained.

  Further, when the traveling motor is in a traveling state in which the output horsepower of the upper limit value Pmax (Mr = 1300 kW) is fully consumed by the traveling motor, for example, when traveling uphill, the horsepower consumed by the other prime mover load 18 should be less than 200 kW. (For example, if there is only about 50 kW), since the output horsepower of the prime mover 4 has a margin, the rotational speed deviation ΔN becomes ΔN> ΔN1 in the automatic target rotational speed increase / decrease process of the procedure 102 of FIG. 5 (block 202 of FIG. 4). The target rotational speed Nr gradually decreases (procedures 231 and 232 in FIG. 17), and the rotational speed of the prime mover 4 also decreases accordingly. When the target rotational speed Nr decreases and the rotational speed deviation ΔN becomes ΔN2 <ΔN ≦ ΔN1, the target rotational speed Nr at that time is maintained (steps 235 and 236 in FIG. 17), and the prime mover 4 has the target rotational speed Nr. Be controlled. When the target rotational speed Nr further decreases to an intermediate rotational speed Nmid of 1500 rpm, the intermediate rotational speed Nmid is maintained (Nr = Nmid) (steps 233 and 234 in FIG. 17), and the prime mover 4 is controlled at the intermediate rotational speed. Is done.

  Further, when the horsepower consumption of the traveling motor is smaller than the output horsepower upper limit value Pmax (Mr = 1300 kW), such as when traveling at a low speed on a flat road, the output horsepower of the prime mover 4 similarly has a margin, so the procedure of FIG. An operation is performed in which the target rotational speed of the prime mover 4 is reduced by the automatic target rotational speed increase / decrease process 102 (block 202 in FIG. 4).

  Thus, even during traveling, when the prime mover 4 has a margin, the rotational speed of the prime mover 4 can be automatically lowered to reduce the fuel consumption.

  As described above, according to the present embodiment, when the load on the prime mover 4 is light, the number of revolutions of the prime mover 4 can be lowered and the fuel consumption can be reduced.

  Further, since the relationship between the operation amount p of the accelerator pedal 1 and the motor output horsepower coincides, a good operation feeling can be obtained.

Another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, in the target rotational speed automatic increase / decrease process, the initial target rotational speed when the accelerator pedal is depressed is replaced with the maximum rotational speed and is set to a value corresponding to the operation amount of the accelerator pedal based on the function.

  FIG. 18 is a flowchart showing the entire target rotational speed automatic increase / decrease process in the present embodiment. In the figure, the same reference numerals are given to procedures equivalent to those shown in FIG.

  In FIG. 18, in step 201, the operation amount (accelerator operation amount) p of the accelerator pedal 1, the current target rotational speed Nr of the prime mover 4, and the actual rotational speed Ne of the prime mover 4 are read.

  In step 201A, the accelerator operation amount p read in step 201 is referred to the accelerator operation amount vs. target rotation number data map represented by the target rotation number function Nr0 (p) as shown in FIG. The corresponding target rotational speed Nr0 is calculated.

  In FIG. 19, the function Nr0 (p) indicates that the target rotational speed Nr0 is the minimum rotational speed Nmin (idle rotational speed) of the prime mover 4 when the operation amount p of the accelerator pedal 1 is in the range from 0 for no operation to the micro operation amount P0. When the accelerator operation amount p is in the range from p0 to the operation amount p2 before the maximum operation amount pmax, the target rotational speed Nr0 becomes the minimum rotational speed as the operation amount p of the accelerator pedal 1 increases. When the accelerator operation amount p increases from Nmin to the maximum rotation number Nmax and the accelerator operation amount p exceeds the operation amount p2, the target rotation number Nr0 is set to be constant at the maximum rotation number Nmax.

  The minimum rotation speed Nmin is, for example, a rotation speed within a range of 700 rpm to 800 rpm, and is 750 rpm in the illustrated example. The maximum rotation speed Nmax is preferably the maximum rated rotation speed of the prime mover 4 and is, for example, a rotation speed within a range of 1800 rpm to 2100 rpm, and is 2000 rpm in the illustrated example.

  Further, the operation amount p2 before the maximum operation amount pmax is preferably an operation amount of 80% to 95% of the maximum operation amount pmax, and is 95% of the maximum operation amount pmax in the illustrated example.

  The minute operation amount p0 is preferably an operation amount within a range of 2 to 8% of the maximum operation amount pmax of the accelerator pedal, and is 5% of the maximum operation amount pmax in the illustrated example.

In step 202, the actual rotational speed Ne is subtracted from the target rotational speed Nr of the prime mover 4 based on the current target rotational speed Nr and the actual rotational speed Ne of the prime mover 4 read in the procedure 201, and the rotational speed deviation ΔN is calculated. . That is,
ΔN = Ne−Nr
In step 203, the current state flag C is read. The following four types are registered in the current status flag C.

C = I: Idle state C = M: Maximum rotational speed state C = A: Automatic decrease state C = m: Intermediate rotational speed state In steps 204A to 206A, mode control according to the current state flag C is performed. That is, if C = I, idle mode control is performed (procedure 204A), if C = M, maximum speed mode control is performed (procedure 205), and if C = A, automatic decrease mode control is performed (procedure 204A). 206A).

  Details of the three types of mode control will be described with reference to FIGS.

  20 is a flowchart showing details of idle mode control, FIG. 21 is a diagram showing details of maximum rotation speed mode control, and FIG. 22 is a diagram showing details of automatic reduction mode control.

  In FIG. 20 showing the idle mode control, first, in step 211, it is determined whether the accelerator operation amount p is smaller than the minute operation amount p0 shown in FIG. 19, and if yes (p <p0), in step 212A, As the target rotational speed Nr, the target rotational speed Nr0 (p) = Nmin calculated in the procedure 201A of FIG. 18 is set (Nr = Nr0 (p) = Nmin). If no (p ≧ p0), then in the step 214A, As the target rotational speed Nr, the target rotational speed Nr0 calculated in the procedure 201A of FIG. 18 is set (Nr = Nr0). That is, the minimum rotational speed Nmin is set in the procedure 212A, and the maximum rotational speed Nr0 corresponding to the operation amount p at that time is set in the procedure 214A.

  When the minimum rotation speed Nmin is set as the target rotation speed Nr in the procedure 212A, the count value of the timer 1 is cleared in the procedure 213 (timer 1 = 0), and then the procedure returns to the start and the above procedure is repeated. In step 214A, when the maximum rotation speed Nr0 is set as the target rotation speed Nr, in step 215, the state flag C is set to M (maximum rotation speed state) (C = M), and then the process returns to the start and the above procedure is performed. repeat.

  In FIG. 21 showing the maximum rotational speed mode control, it is determined in step 221 whether the rotational speed deviation ΔN is larger than the set value ΔN1, and if yes (ΔN> ΔN1), the timer 1 is counted up in step 222, If no (ΔN ≦ ΔN1), the process returns to the start and the above procedure is repeated. After counting up timer 1 in step 222, it is determined in step 223 whether the count value of timer 1 has reached the set value N1. If no, the procedure returns to the start and the above procedure is repeated. At 224, the state flag C is set to A (automatic decrease state) (C = A), the count value of timer 1 is cleared at step 225 (timer 1 = 0), and the above procedure is repeated after returning to the start. The set value ΔN1 is, for example, +5 rpm, and the set value N1 is a count value corresponding to, for example, 2 to 3 seconds.

  In FIG. 22 showing the automatic reduction mode control, in step 231, in step 231, it is determined whether the rotational speed deviation ΔN is larger than the set value ΔN 1. If yes (ΔN> ΔN 1), in step 232, A predetermined value δN is subtracted from the target rotational speed Nr to obtain a new target rotational speed Nr (Nr = Nr−δN). In step 233, whether or not the new target rotational speed Nr has reached the intermediate rotational speed Nmid is determined. If no (Nr> Nmid), the procedure returns to the start and the above procedure is repeated. If yes (Nr = Nmid), the target rotational speed Nr is maintained at the intermediate rotational speed Nmid in step 234 (Nr = Nmid). ). Here, the predetermined value δN is, for example, 0.1 rpm for a calculation cycle of 10 ms. Further, as shown in FIG. 19, the intermediate rotational speed Nmid is a rotational speed near the middle between the minimum rotational speed (idle rotational speed) Nmin and the maximum rotational speed Nmax, and is, for example, 1500 rpm.

  If the determination in step 231 is no (ΔN ≦ ΔN1), it is determined in step 235 whether the rotational speed deviation ΔN is larger than the set value ΔN2, and if yes (ΔN> ΔN2), in step 236, The target rotational speed Nr is maintained at the target rotational speed Nr at that time (Nr = Nr). Here, the set value ΔN2 is smaller than the set value ΔN1 (ΔN2 <ΔN1). When the set value ΔN1 is, for example, +5 rpm, the set value ΔN2 is, for example, −20 rpm. If the determination in step 235 is no (ΔN ≦ ΔN1), the state flag C is set to M (maximum speed state) in step 237 (C = M), and the target speed Nr is set in step 237A. Then, the target rotational speed Nr0 (the maximum rotational speed Nr0 corresponding to the operation amount p at that time) calculated in the procedure 201A of FIG. 18 is set (Nr = Nr0), and the procedure is repeated after returning to the start.

  Also in the present embodiment configured as described above, as in the previous embodiment, when the load on the prime mover 4 is light, the number of revolutions of the prime mover 4 can be reduced and the fuel consumption can be reduced. In the present embodiment, the maximum number of revolutions is set as a value corresponding to the amount of operation of the accelerator pedal at that time, so that the maximum number of revolutions can be set according to the will of the operator.

  While one embodiment of the present invention has been described above, various modifications can be made within the spirit of the present invention. For example, in the above-described embodiment, the maximum horsepower Mr that can be used by the electric motors 12R and 12L in step 111 (block 211) with reference to the actual rotation speed Ne of the prime mover 4 with the function Mr (Ne) of the motor maximum output horsepower. However, normally, the accelerator pedal is not operated suddenly, and the actual rotational speed Ne of the prime mover 4 is approximately equal to the target rotational speed Nr. Therefore, instead of the actual rotational speed Ne of the prime mover 4, the target rotational speed Nr is used. The maximum horsepower Mr that can be used by the electric motors 12R and 12L may be obtained. Further, the maximum horsepower Mr is set to ½, and the output horsepower upper limit value Pmax per electric motor 12R, 12L is calculated. In step 118 (block 217), the motor output horsepower upper limit value Pmax and the motor target output horsepower Pm0 are calculated. After the smaller value is selected, the motor output target horsepower Pm may be set to ½.

  Moreover, although the electric motors 12R and 12L are induction motors, they may be synchronous motors.

1 is a diagram showing an overall configuration of an electric drive dump truck drive system according to an embodiment of the present invention. It is a figure which shows the relationship between the real rotation speed of a motor | power_engine, and output torque. It is a figure which shows the fuel injection characteristic of an electronic governor. It is a functional block diagram which shows the process sequence of the drive system by this Embodiment. It is a flowchart which shows a process sequence. It is a flowchart which shows a process sequence. It is a figure which shows the data map of the engine speed represented by the function Mr (Ne) of motor maximum output horsepower versus motor maximum output horsepower. It is a figure which shows the data map of the rotational speed versus prime mover maximum output horsepower represented by the function f (Ne), and the data map of the rotational speed represented by the function g (Ne) versus other prime mover load loss horsepower. It is a figure which shows the data map of the amount of accelerator operation versus motor target output horsepower represented by the function Pm1 (p) of the 1st motor target output horsepower at the time of advance. It is a figure which shows the data map of the accelerator operation amount versus motor target output horsepower represented by the function Pm2 (p) of the 2nd motor target output horsepower at the time of reverse drive. It is a figure which shows the relationship between motor output target horsepower Pm, rotation speed (omega) R, (omega) L of an electric motor, and motor target torque Tr1R, Tr1L. It is a figure which shows the data map of the motor rotation speed versus motor maximum torque represented by the function Trmax1 ((omega)) of motor maximum torque. It is a flowchart which shows the whole target rotation speed automatic increase / decrease process. It is a flowchart which shows the detail of idle mode control. It is a figure which shows the target rotation speed Nr according to the accelerator operation amount p set by idle mode control. It is a flowchart which shows the detail of maximum rotation speed mode control. It is a flowchart which shows the detail of automatic reduction mode control. It is a flowchart which shows the whole target rotation speed automatic increase / decrease process concerning the 2nd Embodiment of this invention. It is a figure which shows the data map of the accelerator operating quantity versus target rotational speed represented with the function Nr0 (p) of target rotational speed. It is a flowchart which shows the detail of idle mode control. It is a flowchart which shows the detail of maximum rotation speed mode control. It is a flowchart which shows the detail of automatic reduction mode control.

Explanation of symbols

1 accelerator pedal 2 retard pedal 3 overall control device 4 prime mover (diesel engine)
5 AC generator 6 Rectifier circuit 7 Inverter controller 8 Chopper circuit 9 Grid resistor 10 Capacitor 11 Resistors 12R and 12L for detecting the voltage after rectification Left and right electric motors (induction motors)
13R, 13L Reducers 14R, 14L Left and right rear wheels (tires)
15R, 15L Electromagnetic pickup sensor 16 Shift lever 18 Other prime mover loads 71R, 71L Torque command calculation units 72R, 72L Motor control calculation units 73R, 73L Inverters (switching elements)
ΔN1 first set value ΔN2 second set value (<ΔN1)
Nmin Minimum speed (initial target speed)
Nmax Maximum food factor (initial target speed)
Nmid intermediate speed

Claims (7)

Prime mover,
An electronic governor that controls the speed and torque of the prime mover;
An alternator driven by the prime mover;
A prime mover load other than the AC generator driven by the prime mover;
In the drive system of an electric drive dump truck having at least two electric motors for traveling driven by power supplied from the AC generator,
An accelerator pedal,
Motor control means for controlling the electric motor based on an operation amount of the accelerator pedal;
A prime mover control means for controlling the prime mover by controlling the electronic governor,
The prime mover control means includes
A first means for calculating a rotational speed deviation obtained by subtracting a current target rotational speed of the prime mover from an actual rotational speed of the prime mover;
Second means for obtaining an initial target rotational speed of the prime mover based on an operation amount of the accelerator pedal, and setting the initial target rotational speed as a target rotational speed of the prime mover;
And a third means for gradually decreasing the target rotational speed of the prime mover when the rotational speed deviation is larger than a first set value. The drive system for an electrically driven dump truck according to claim 1,
When the third means gradually decreases the target rotational speed of the prime mover, when the rotational speed deviation is smaller than the first set value and larger than the second set value smaller than the first set value, A drive system characterized by maintaining a target rotational speed and increasing the target rotational speed of the prime mover when the rotational speed deviation becomes smaller than a second set value. The drive system for an electrically driven dump truck according to claim 1,
When the third means gradually reduces the target rotational speed, if the target rotational speed decreases to an intermediate rotational speed higher than the minimum rotational speed, a fourth means for holding the target rotational speed at the intermediate rotational speed is further provided. A drive system characterized by comprising a drive system. The drive system for an electrically driven dump truck according to claim 1,
When the target rotational speed is gradually decreased, the third means returns the target rotational speed to the initial target rotational speed as soon as the rotational speed deviation becomes smaller than a second set value. . The drive system for an electrically driven dump truck according to claim 1,
The third means increases the target rotational speed to the maximum rotational speed as soon as the rotational speed deviation becomes smaller than a second set value when gradually reducing the target rotational speed. The drive system for an electrically driven dump truck according to claim 1,
The second means sets a minimum rotation speed as the initial target rotation speed when the accelerator pedal is not operated, and sets a maximum rotation speed as the initial target rotation speed when the accelerator pedal is operated. A drive system characterized by: The drive system for an electrically driven dump truck according to claim 1,
The second means sets a minimum rotation speed as the initial target rotation speed when the accelerator pedal is not operated, and operates the accelerator pedal as the initial target rotation speed when the accelerator pedal is operated. A drive system characterized by setting the number of rotations according to the amount.

Images