JP4609736B2 - Electric motor control device - Google Patents

Description

  The present invention relates to an electric motor control device that controls an electric motor that operates a load based on an operation of an operation end.

  For hydraulic excavators, hydraulic crane swiveling operations, wheel loader traveling operations, construction equipment, etc., and driving devices that operate mass and inertia (hereinafter referred to as loads) such as suspended loads and earth and sand (hereinafter referred to as loads) Many hydraulic drive devices using a pump or a hydraulic motor are employed. In recent years, instead of a hydraulic drive system using a hydraulic drive apparatus with a large energy loss in order to throttling hydraulic energy with a control valve, an electric drive system that drives a load with an electric motor with a small energy loss is being adopted. The electric drive system also has an advantage that braking energy can be regenerated using the electric motor as a generator when the load is lowered in the direction of gravity or when the load is decelerated.

  However, the hydraulic drive system using the conventional hydraulic drive device is easy to operate so that the operability of the operator controlling the operation of the load by operating the operation end such as a lever or a pedal fits the human operation sense. In contrast to the design, the electric drive system using an electric motor cannot realize the operability and operation feeling like the hydraulic drive system, and there is a problem that it is difficult for the operator to operate.

  In other words, in the hydraulic drive system, the opening area of the bleed-off control throttle and meter-out control throttle of the spool valve is controlled by the operation of the operation end, so that the amount of operation at the operation end and the flow rate through each control throttle The differential pressure is controlled. The output pressure of the hydraulic motor is controlled by the differential pressure, and smooth load acceleration, deceleration and stop are performed. When driving a load against gravity, such as when starting a running hill or turning up a turning hill, reverse rotation is prevented by the load check valve, and if the output torque of the hydraulic motor becomes larger than the load torque, power running operation is performed. Start. On the other hand, in the case of the electric drive system, when the rotation speed of the motor is controlled, the speed control is performed with the output torque as the maximum value, so the acceleration and deceleration of the load become steep and smooth operability like the hydraulic drive system. There is a problem that the operational feeling of the operator is far from the hydraulic drive system. In addition, when the output torque of the motor is controlled according to the operation amount at the operation end, if the operation amount at the operation end is small and the output torque is smaller than the torque due to the gravity of the load, the power running operation of the motor cannot be performed and regeneration is performed. There is a problem that the operation rotates in the direction opposite to the operation direction of the operation end.

  In order to solve such a problem, the present applicant has applied for a patent for a technique for making the operability and operation feeling when operating an inertial body such as a construction machine by an electric drive system equivalent to that of a hydraulic drive system. (PCT / JP2007 / 062232: hereinafter referred to as the application).

  In the above application, the rotational drive of the electric motor that operates the inertial body is controlled by the operation of the operation end that makes at least the operation amount variable, the operation detection means that detects the operation amount of the operation end, the rotation direction and the rotation speed of the motor. Rotation detecting means for detecting, calculating means for calculating a target torque to be borne by the electric motor based on detection values of the operation detecting means and the rotation detecting means, and the output torque of the electric motor in the direction and magnitude of the target torque. An electric motor control means for controlling the power, and the output torque is a power running torque as a motor function of the motor and a regenerative torque as a generator function. The amount and the absolute value of the rotation speed of the electric motor are uniquely determined, and the absolute value of the operation amount at the operation end increases, and even if the operation amount at the operation end is constant, By incorporating an algorithm that decreases as the absolute value of the rotational speed of the motive increases, it has the same control characteristics as the control of the bleed-off pressure in the hydraulic drive system, making it easier for the operator to control the target operating speed. The control based on a simple algorithm makes it possible to obtain the same operability and operation feeling as the hydraulic drive system.

  Further, in the above application, when the absolute value of the manipulated variable at the operating end becomes small, the regenerative torque becomes large when the absolute value of the rotational speed of the electric motor becomes small even if the manipulated value at the operating end is constant. By incorporating a smaller algorithm, the same control characteristics as the meter-out pressure control of the hydraulic drive system are provided, and the operability and operation feeling similar to those of the hydraulic drive system can be obtained.

  Further, in the application, the operation end is variable in both plus and minus directions in addition to the operation amount, and the electric motor is driven to rotate in both plus and minus directions. The operation direction is to be detected, and when the operation amount of the operation end is in a neutral range including zero, or when the operation direction of the operation end is opposite to the rotation direction of the motor, By incorporating an algorithm that increases the absolute value of the regenerative torque according to the magnitude of the absolute value of the rotation speed of the motor in a small range where the absolute value is close to zero, the inertial body starts on a slope, or the inertial body is moved on a sloping ground. When turning upwards, the inertial body is prevented from descending and retreating and returning downward, so that it is possible to smoothly start the slope and turn upward.

  In the application, when the operation amount of the operation end is in the neutral range, or when the operation direction of the operation end and the rotation direction of the motor are opposite directions, the absolute value of the rotation speed of the motor is a small range near zero, The regenerative torque is calculated to increase according to the magnitude of the absolute value of the rotation speed, and when the turning body is turned upward on an inclined ground, the power running torque is smaller than the load torque due to the inclination. When the power running torque is larger than the load torque, the turning body starts to turn upward smoothly by this power running torque. However, when the regenerative torque due to the load is large and the motor is performing regenerative operation, while the power running torque is smaller than the torque due to the load, the regenerative operation was performed at the rotational speed corresponding to the magnitude of the torque due to the load. As soon as the power running torque becomes larger than the torque due to the load, the speed change becomes discontinuous even though the motor is operating at low speed near zero. There is a problem of poor operability. Furthermore, such a problem is a problem that generally arises not only when driving an inertial load but also when driving a mass against gravity.

  Therefore, an object of the present invention is to control the operation based on a simple algorithm, when starting a traveling body on an uphill road (starting on a slope), or turning a turning body upward on a sloping ground, lowering or retreating a load or turning down a load. It is an object of the present invention to provide an electric motor control device that can smoothly start a slope and turn upward without a discontinuous change in speed.

In order to solve the above-described problem, the rotation drive of the electric motor that operates the load is controlled by the operation of the operation end that makes the operation amount variable, and the operation detection unit that detects the operation amount of the operation end; An electric motor control device comprising: a rotation detecting means for detecting a rotation speed; and an output torque detecting means for detecting an output torque of the electric motor. The electric motor is controlled based on detection values of the operation detecting means and the rotation detecting means. Computation means for computing the direction and magnitude of the target torque to be borne, and electric motor control means for controlling the electric motor, the direction and magnitude of the target torque being input to the electric motor control means, The output torque is controlled in the direction and magnitude of the target torque, and the target torque drives the electric motor by the power running torque that drives the load by the electric motor and the load. When the operation amount of the operation end is in a neutral range including zero, or when the operation direction of the operation end and the rotation direction of the electric motor are opposite to each other, When the power running torque is zero, the absolute value of the regenerative torque is the maximum value, and the regenerative operation is performed in a range where the rotation speed of the motor is extremely low, the absolute value of the output torque of the motor and the target during the power running operation of the motor A configuration was adopted in which an algorithm for controlling the rotational speed of the electric motor according to the magnitude of the difference in torque was incorporated.

That is, from the detection values of the operation detection means for detecting the operation amount of the operation end and the rotation detection means for detecting the rotation speed of the electric motor, the direction and the magnitude of the target torque to be borne by the electric motor are calculated by the calculation means, When the torque of the electric motor is controlled to the direction and magnitude of the target torque and the operation amount of the operation end is in a neutral range including zero, or when the operation direction of the operation end and the rotation direction of the electric motor are opposite directions, When the power running torque for driving the load of the target torque is zero, the absolute value of the regenerative torque driven by the load is the maximum value, and the regenerative operation is performed in a range where the rotational speed of the motor is extremely low, the motor by the controlling the rotational speed of the motor according to the magnitude of the absolute value and the difference between the target torque during power running operation of the motor output torque, it was upward pivot sloping ground or to hill start load When, by suppressing the lowering recession and downward rotational loads, which make it possible to perform hill start or upward pivoting smoothly without discontinuous change in rotational speed.

  In a hydraulic drive apparatus that drives the hydraulic motor 53 with the hydraulic pump 52 by operating the spool valve 51 as shown in FIG. 7, a machine (not shown) that acts on the drive shaft of the hydraulic motor 53 when the operation end is operated. The brake is released, and the hydraulic motor 53 itself bears the torque due to the gravity of the load. Even if the opening area of the bleed-off control throttle 51a of the spool valve 51 is large and the bleed-off pressure P0 is lower than the pressure due to the gravity of the load, the load check valve 51d causes the hydraulic motor 53 to reverse the operation direction of the operation end. However, the hydraulic motor 53 itself reverses at a very low speed due to internal leakage of the hydraulic motor 53. When the bleed-off pressure P0 becomes higher than the pressure due to the gravity of the load, the hydraulic motor 53 starts to rotate (forward rotation) in the operation direction of the operation end. In this case, the speed of reverse rotation is determined by the magnitude of the pressure due to the gravity of the load, and when the bleed-off pressure P0 becomes higher than the pressure due to the gravity of the load, it suddenly rotates forward, so the rotation of the hydraulic motor 53 is discontinuous. Become. When regenerative operation is performed within the range of extremely low speeds of the motor, the rotational speed is discontinuous by controlling the rotational speed of the motor according to the magnitude of the difference between the absolute value of torque due to the gravity of the load and the power running torque. The vehicle can smoothly start on a slope and turn upward without any change, and can achieve performance superior to that of a hydraulic drive.

In the motor control device, the target torque during the power running operation is uniquely determined by the operation amount of the operation end and the absolute value of the rotation speed of the motor, and increases as the absolute value of the operation amount of the operation end increases. A configuration is adopted in which a calculation algorithm that decreases as the absolute value of the rotational speed of the electric motor increases is incorporated.

That is, the target torque during powering operation is uniquely determined by the operation amount at the operating end and the absolute value of the rotation speed of the motor, and increases as the absolute value of the operation amount at the operating end increases, and the absolute value of the rotation speed of the motor becomes By incorporating a calculation algorithm that becomes smaller as it becomes larger, it has the same control characteristics as the bleed-off pressure control in the hydraulic drive system, making it easier for the operator to control the target operating speed and reducing the amount of operation at the operating end. The power running torque increases as the value increases, and the rotational speed of the regenerative operation of the motor at extremely low speed is controlled according to the magnitude of the difference from the absolute torque value due to the gravity of the load. When it becomes larger than the load torque, the power running operation starts and acceleration can be started smoothly.

  As shown in FIG. 8, in the hydraulic drive apparatus that drives the hydraulic motor 53 with the hydraulic pump 52 by operating the spool valve 51 as shown in FIG. The opening area of the bleed-off control throttle 51a is reduced, the bleed-off pressure P0 is increased, the driving torque of the hydraulic motor 53 is increased, and the bleed-off flow rate is decreased as the rotational speed of the hydraulic motor 53 is increased. Even if the opening area of the bleed-off control throttle 51a is constant, the bleed-off pressure P0 is lowered and the driving torque is controlled to be reduced. Therefore, when the rotational speed of the hydraulic motor 53 increases, the driving torque gradually decreases, and the acceleration of the inertial body disappears at a value commensurate with the driving resistance due to friction of the driving system or pressure loss of the hydraulic piping system or the spool valve 51, and the operator can The operation speed is controlled as follows. Therefore, by incorporating the above algorithm, it is possible to have the same control characteristics as the control of the bleed-off pressure P0 of such a hydraulic drive system.

  The electric motor may be an electric motor that drives turning or traveling of a construction machine.

The motor control device according to the present invention includes a direction of a target torque to be borne by the motor by the calculation means based on the detection values of the operation detection means for detecting the operation amount of the operation end and the rotation detection means for detecting the rotation speed of the motor. And the motor torque is controlled to the direction and magnitude of the target torque, and when the operation amount at the operation end is in the neutral range including zero, or the operation direction of the operation end and the rotation direction of the motor are reversed. Of the target torque, the power running torque that drives the load is zero, the absolute value of the regenerative torque driven by the load is the maximum value, and the regenerative operation is performed in the range where the rotation speed of the motor is extremely low to, by controlling the rotational speed of the motor in accordance with the magnitude of the difference between the target torque when the absolute value and the power running operation of the output torque of the electric motor, when or to upward pivoting in sloping ground or to a hill start the load, By suppressing the lowering recession and downward rotational of the load, and to be able to perform hill start or upward pivoting smoothly without discontinuous change in rotational speed.

The target torque during the power running operation is uniquely determined by the operation amount of the operation end and the absolute value of the rotation speed of the electric motor, and increases as the absolute value of the operation amount of the operation end increases. By incorporating a calculation algorithm that becomes smaller as the absolute value becomes larger, it has control characteristics similar to the control of the bleed-off pressure in the hydraulic drive system, making it easy for the operator to control the target operating speed, and the operation terminal The target torque during the power running operation increases as the operation amount increases, and the rotational speed of the regenerative operation of the motor at a very low speed according to the magnitude of the difference from the absolute value of the torque due to the gravity of the load When the target value of the power running torque becomes larger than the load torque, the power running operation starts and acceleration can be started smoothly.

  By using the motor control device as described above as the motor control device for driving the turning or running of the construction machine, it is very easy to operate as a device having the same control characteristics as the hydraulic drive system. It can be a device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hydraulic excavator incorporating an electric motor control device according to the present invention. The hydraulic excavator includes a crawler type lower traveling body 20, an upper revolving body 30 as an inertial body that pivots left and right on the lower traveling body 20, and an excavation attachment 40 attached to the front portion of the revolving body 30. It consists of. The lower traveling body 20 travels by the left and right crawlers 23 being individually driven by the traveling hydraulic motor 21 and the speed reducer 22. The excavation attachment 40 includes a boom 41, an arm 42, and a bucket 43, and a boom cylinder 41a, an arm cylinder 42a, and a bucket cylinder 43a for operating them.

  The revolving body 30 is equipped with an engine 31, a hydraulic pump 32 and a generator 33 driven by the engine 31, a power storage device 34 such as a battery and a capacitor, and an electric motor 1 and a speed reducer 35 that rotate the revolving body 30. Has been. The oil discharged from the hydraulic pump 32 is supplied to the traveling hydraulic motor 21, the boom 41, the arm 42, and the cylinders 41 a, 43 a of the bucket 43 via control valves. Further, as shown in FIG. 2, the electric power of the generator 33 is stored in the power storage device 34 with the voltage and current controlled by the converter 37 and supplied to the electric motor 1 via the inverter 4 described later. The electric motor 1 is a permanent magnet type motor having a permanent magnet as a rotor, and the electric motor control device according to the present invention controls the electric motor 1 to rotate the revolving body 30.

FIG. 2 is a block diagram showing the configuration of the control device of the electric motor 1. This control device rotates in both directions, an operation detection means 2a for detecting an operation amount X in both plus and minus directions of the operation lever 2 as an operation end, a speed limit value setting means 5 for setting a speed limit value Y of the motor. The motor 1 should bear from the rotation detection means 1a for detecting the plus / minus rotation speed N of the electric motor 1, the detected operation amount X of the operation lever 2, the speed limit value Y, and the rotation speed N of the electric motor 1. The direction and magnitude of the target torque To is calculated, and when the regenerative operation is performed in the range where the rotation speed of the motor is extremely low, the difference between the absolute value of the output torque of the motor and the target torque during the power running operation is calculated. Accordingly, the controller 3 outputs the output torque T of the motor 1 with respect to the power supplied from the generator 33 or the power storage device 34 as a calculation means for calculating the speed of the motor. And an inverter 4 as a motor control means for controlling the target speed has been controlled in the direction and magnitude of the target torque To, or range extremely low in the rotational speed of the motor 1.

  The controller 3 is provided with a memory 3a, and a calculation algorithm 3b for calculating the target torque To is expressed in advance in the memory 3a so as to express the control characteristics of the hydraulic drive system. The target torque To is a power running torque when it is output in the same direction as the operation direction of the operation lever 2, and is a regenerative torque when it is output in the direction opposite to the operation direction. The inverter 4 includes a signal conversion circuit 4a, a current control circuit 4b, and a current detection circuit 4d. The signal conversion circuit 4a converts the target torque To input from the controller 3 into the target current Io, and the current control circuit 4b. The current detection circuit 4d performs feedback control so that the output current I to the motor 1 becomes the target current Io.

  Further, the current detection circuit 4d and the signal conversion circuit 4c constitute output torque detection means for detecting the output torque of the electric motor. Since the output torque of the motor, T, and current I are in a proportional relationship, the output torque of the motor can be calculated by detecting the current 1 of the current feedback circuit of the inverter 4. When the electric motor 1 is regenerating at a very low speed in the direction opposite to the operation direction of the operation lever 2, the output torque T of the electric motor is equal to the torque TL due to the gravity of the load. The detection value of the current detection circuit 4d is signal-converted as the output torque TL of the electric motor 1 by the signal conversion circuit 4c and input to the controller.

  FIG. 3 shows a map for calculating the target torque To by the calculation algorithm 3b. In this map, the horizontal axis is the plus / minus operation amount X of the control lever 2, the vertical axis is the target torque To, and these relationships are represented by a characteristic curve with the plus / minus rotational speed N of the motor 1 as a parameter. In the first quadrant and the third quadrant in which the operation amount X and the target torque To have the same sign, the target torque To becomes the power running torque, and the second quadrant and the fourth quadrant in which the operation amount X and the target torque To have different signs. In the quadrant, the target torque To is the regenerative torque. That is, in the first quadrant, the right turning power running, in the second quadrant, the left turning regeneration, in the third quadrant, the left turning power running, and in the fourth quadrant, the right turning regeneration. In the graph of FIG. 3, in order to make the map easy to see, each characteristic curve is displayed only when the parameter rotation speed N = 0, 1/2, 1 (maximum speed).

  In the first quadrant and the third quadrant of FIG. 3, the absolute value of the target torque To that becomes the power running torque increases as the absolute value of the operation amount X of the operation lever 2 increases, and even if the operation amount X is constant, When the absolute value of the rotational speed N of the electric motor 1 is increased, the calculation is performed so that the absolute value of the rotation speed N decreases, and control characteristics similar to the control of the bleed-off pressure in the hydraulic drive system can be obtained. In the second quadrant and the fourth quadrant, the absolute value of the target torque To, which is the regenerative torque, increases as the absolute value of the manipulated variable X decreases. Even if the manipulated variable X is constant, the absolute value of the rotational speed N The value is calculated so as to decrease as the value decreases, and control characteristics similar to the meter-out pressure control in the hydraulic drive system can be obtained.

  Further, in the map shown in FIG. 3, when the operation amount X is in a neutral range including zero, and when the operation direction of the operation lever 2 and the rotation direction of the electric motor 1 are opposite directions, the power running torque is zero and the regenerative torque is The absolute value is set to the maximum value Tmax. Therefore, for example, when the rotational speed N is 1/2 (Q1 point) in the fourth quadrant, the operation amount X of the operation lever 2 is changed from X1 to -X2, as indicated by an arrow in the figure. When operating in the direction opposite to the rotational direction, the regenerative torque is output at Tmax until the rotational speed N becomes zero, the right turn is decelerated, and when the rotational speed N becomes zero, the manipulated variable X in the third quadrant The power running torque corresponding to the rotational speed N = 0 (Q2 point) when the power is set to −X2 is output, and acceleration is started so as to turn the revolving body 30 to the left. In this embodiment, the absolute value of the power running torque is also set to the same maximum value Tmax as the regenerative torque.

FIG. 4 is a diagram expressing the map of FIG. 3 in another way. Since the target torque To is uniquely determined by the operation amount X at the operating end and the absolute value N of the rotational speed of the electric motor, a predetermined relational expression expressed as To = f (X, N) is used, with N as a parameter. As shown in FIG. 4, or with X as a parameter, it can be expressed as shown in FIG. Only the range where the rotational speed N of the electric motor 1 is small is shown. As the operation amount X increases from 0 to the maximum, the absolute value of the power running torque increases. When the absolute value of the rotational speed N increases, the power running torque decreases and the absolute value of the regenerative torque increases. When the target torque during the power running operation is smaller than the torque TL due to the gravity of the load, the electric motor 1 performs a regenerative operation at an extremely low rotational speed. In the embodiment of FIG. 4, when the operation amount of the operation lever 2 is 0, the electric motor performs a regenerative operation at a rotation speed of NL.

FIG. 5 shows the relationship between the rotational speed of the motor in accordance with the magnitude of the difference between the absolute value of the torque due to the gravity of the load and the target torque during the power running operation when the rotational speed of the motor is regeneratively operated. is there. The rotational speed of the electric motor is controlled at a very low speed according to the magnitude of the difference ΔT (ΔT = TL−To) between the absolute value TL of the torque due to the gravity of the load and the target torque To during the power running operation .

FIG. 6 shows the calculation algorithm 3b according to the magnitude of the difference between the absolute value of the torque due to the gravity of the load and the target torque during the power running operation when the regenerative operation is performed in a range where the rotation speed of the motor is extremely low. It is a flowchart of the algorithm which controls the speed of an electric motor. In step 1 (S1), the operation amount X is calculated. In step 2 (S2), the rotational speed N of the electric motor is calculated. In step 3 (S3), the target torque To of the motor is calculated from the operation amount X calculated in S1 and S2 and the rotational speed N of the motor. In step 4 (S4), the target torque To of the motor is output, and the inverter 4 is controlled so that the output torque of the motor becomes To. In step 5 (S5), the rotational speed N of the electric motor is calculated. In step 6 (S6), it is determined whether the rotation direction of the electric motor is the same as the operation direction of the operation lever (N ≧ 0). If YES, return to the original and perform the same calculation and control. If NO in S6, it is determined in step 7 (S7) whether or not the absolute value of the rotational speed of the motor is greater than a predetermined extremely low speed (α). If YES, return to the original and perform the same calculation and control. If NO in S7, the torque TL due to the gravity of the load, that is, the output torque T of the motor is calculated in Step 8 (S8). In step 9 (S9), a difference ΔT (ΔT = TL−To) between the absolute value TL of the torque due to the gravity of the load and the target torque To during the power running operation is calculated. In step 10 (S10), the rotational speed N of the motor is calculated from the difference ΔT between the absolute value TL of the torque due to the gravity of the load and the target torque To during the power running operation . In step 12 (S12), the rotational speed N of the electric motor is output, and the inverter 4 controls the rotational speed of the electric motor to be N.

  In the above-described embodiment, the generator and the power storage device are used as power sources to control the electric motor that swings the upper swing body of the excavator left and right. However, the motor control device according to the present invention includes, for example, a wheel The present invention can also be applied to an apparatus that controls an electric motor that operates a load in only one direction, such as an apparatus that runs a loader. Also, the power source of the motor is not limited to a generator or a power storage device. For example, when controlling a motor that operates a device installed in a factory or the like, power supplied from a power company or the like is used as the power source. It can be.

  Further, in the above-described embodiment, the target torque calculation algorithm is stored in the controller as a characteristic curve represented by a map. However, the target torque calculation algorithm uses the operation amount at the operation end and the rotation speed of the motor as parameters. You may make it memorize | store as a numerical formula to do.

The side view which shows the hydraulic excavator incorporating the control apparatus of the electric motor which concerns on this invention The block diagram which shows the structure of the control apparatus of the electric motor integrated in the hydraulic shovel of FIG. Graph showing target torque calculation map Graph showing calculation map of target torque and rotation speed when motor rotation speed is extremely low A graph showing the relationship between the absolute value of the torque due to the gravity of the load and the target torque difference during power running and the motor rotation speed Flowchart of algorithm for controlling the speed of the motor according to the magnitude of the difference between the absolute value of torque due to the gravity of the load and the target torque during powering operation Hydraulic circuit diagram of conventional hydraulic drive The graph which shows the control characteristic of the bleed-off pressure in the hydraulic drive unit of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 1a Rotation detection means 2 Operation lever 2a Operation detection means 3 Controller 3a Memory 3b Arithmetic algorithm which calculates target torque 4 Inverter 4a Signal conversion circuit 4b Current control circuit 4c Signal conversion circuit 4d Current detection circuit 5 Speed limit value setting means 20 Traveling body 21 Traveling hydraulic motor 22 Reducer 30 Revolving body 31 Engine 32 Hydraulic pump 33 Generator 34 Power storage device 35 Reducer 36 Converter 40 Excavation attachment 41 Boom 41a Boom cylinder 42 Arm 42a Arm cylinder 43 Bucket 43a Bucket cylinder

Claims (3)

Operation detection means for controlling rotation driving of the electric motor for operating the load by operation of an operation end with variable operation amount, and detecting the operation amount of the operation end; and rotation detection means for detecting the rotation speed of the electric motor; In the motor control device comprising output torque detection means for detecting the output torque of the motor, the direction and magnitude of the target torque that the motor should bear based on the detection values of the operation detection means and the rotation detection means And a motor control unit for controlling the motor. The direction and magnitude of the target torque are input to the motor control unit, and the output torque of the motor is set as the direction of the target torque. The target torque is composed of a power running torque that drives the load by the motor and a regenerative torque that drives the motor by the load. When the operation amount of the operation end is in a neutral range including zero, or when the operation direction of the operation end and the rotation direction of the motor are opposite to each other, the powering torque is set to zero and the regenerative torque When the regenerative operation is performed in a range where the rotational speed of the motor is extremely low, the absolute value of the motor is a maximum value, and the magnitude of the difference between the absolute value of the output torque of the motor and the target torque during the power running operation of the motor And an algorithm for controlling the rotational speed of the motor.
The target torque during the power running operation is uniquely determined by the operation amount of the operation end and the absolute value of the rotation speed of the electric motor, and increases as the absolute value of the operation amount of the operation end increases. The motor control device according to claim 1, wherein an arithmetic algorithm that decreases as the absolute value increases is incorporated.
  The motor control device according to claim 1, wherein the motor is a motor that drives turning or traveling of a construction machine.

Images