WO2020044791A1

WO2020044791A1 - Electric power converting system, and motor control method

Info

Publication number: WO2020044791A1
Application number: PCT/JP2019/026632
Authority: WO
Inventors: 英人高田; 杉浦　正樹; 卓也石垣; 小林　澄男
Original assignee: 株式会社日立産機システム
Priority date: 2018-08-31
Filing date: 2019-07-04
Publication date: 2020-03-05
Also published as: JP2020036488A; CN112585862B; JP7092620B2; CN112585862A; TWI743541B; TW202011683A; DE112019003804T5

Abstract

This electric power converting system is provided with a power source device 1 for supplying electric power to a motor electric power converting device 2 which supplies electric power to a motor 3, wherein: the motor electric power converting device 2 includes an inverse converter 7 for converting the electric power, a control circuit 8 for controlling the inverse converter 7, and current detectors 59, 60 for detecting currents flowing through the inverse converter 7; the power source device 1 includes an accumulating device 6 for accumulating electric power in accordance with a voltage, a step up/step down power source circuit 5 for changing the voltage of the accumulating device 6 on the basis of a voltage command, and a voltage command calculating circuit 15 for calculating the energy accumulated in the accumulating device 6 and outputting the same as the voltage command to the step up/step down power source circuit 5; and the energy accumulated in the accumulating device 6 is calculated on the basis of powered running energy or regenerative energy of the motor 3, calculated using information from an encoder 10 with which the motor 3 is provided, and electric current values detected by the current detectors 59, 60. In this way, control shifts accompanying changes in characteristics due to degradation over time in the motor load, for example, can be suppressed.

Description

Power conversion system and motor control method

The present invention relates to a power conversion system and a motor control method.

As a conventional technique, for example, Patent Literature 1 discloses a power supply device and a power supply system that include a power supply circuit, a power supply control circuit, and a power storage device, and supply power to a device having a function of storing energy. A power supply device and a power supply system that variably set a control command value of a power storage device based on energy that has been provided are disclosed.

JP 2011-200048 A

In the above prior art, the control command value of the storage device is variably set and controlled based on the rotational energy or the spring energy stored in the inertia load such as the motor and the motor load, thereby achieving low cost, low loss and high density. It is intended to provide a simple power supply device.

特性 Generally, the characteristics of motors and storage devices change due to aging and the like. There is a demand for high-precision control according to changes in characteristics due to these various factors.

The present invention has been made in view of the above requirements.

The present application includes a plurality of means for solving the above-described problems. For example, a power conversion system including a power conversion device that supplies power to a motor and a power supply device that supplies power to the power conversion device are exemplified. In the power conversion device, a power conversion unit that converts power, a control unit that controls the power conversion unit, and a current detection unit that detects a current in the power conversion unit, the power supply device A storage device for storing electric power according to a voltage, a step-up / step-down power supply circuit for changing the voltage of the storage device based on a voltage command, and calculating the energy stored in the storage device as the voltage command, An arithmetic circuit for outputting to a power supply circuit, wherein the control unit uses information from an encoder provided in the motor and a current value detected by the current detection unit to output power running energy of the motor. There calculates the regenerative energy, the arithmetic circuit is assumed for calculating the energy accumulated in the storage device based on the power running energy or regenerative energy of the motor calculated by the control unit.

According to the present invention, it is possible to suppress a shift in control due to a change in characteristics due to aged deterioration of the motor load, and to suppress a deterioration in control accuracy. In addition, excessive storage of power in the storage device can be suppressed, and power loss can be reduced and the size of the storage device can be reduced.

It is a figure showing typically the whole power conversion system composition concerning the present invention. It is a figure explaining rotation or kinetic energy stored in an inertial load. It is a figure which illustrates typically the structure of the press machine with a pneumatic die cushion. It is a figure explaining the energy stored in the pneumatic type die cushion. It is a figure explaining the energy stored in the elevating device. FIG. 4 is a diagram illustrating a relationship between a crankshaft angular speed and a slide speed of the crank press. FIG. 1 is a diagram schematically illustrating an example of a power conversion system according to a first embodiment. FIG. 4 is a diagram illustrating an example of details of a directional converter, a step-up / step-down power supply circuit, and a storage device of the power supply device, in which a circuit that performs a boost operation is used as the step-up / step-down power supply circuit. FIG. 9 is a diagram illustrating another example of the details of the forward converter, the step-up / step-down power supply circuit, and the storage device of the power supply device, and illustrates a case where a circuit that performs a step-down operation is used as the step-up / step-down power supply circuit. FIG. 3 is a diagram illustrating details of an inverter and a position / speed current control circuit of the motor power converter. It is a figure which shows an example of the waveform of the angular velocity detection signal of a slide motor when performing drawing by a press machine with a pneumatic die cushion. It is a figure which shows an example of the waveform of the torque detection signal of a slide motor when drawing is performed by the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of the acceleration / deceleration torque calculation circuit when drawing is performed by the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of the addition / subtraction arithmetic unit when drawing is performed by the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of an inertial load accumulation energy calculation circuit when drawing is performed by the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of the elastic load accumulation energy calculation circuit at the time of performing drawing by the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of the addition arithmetic unit of the accumulation energy arithmetic circuit at the time of performing a drawing process with the press machine with a pneumatic die cushion. It is a figure which shows an example of the output waveform of a voltage command calculation circuit at the time of performing a drawing process with the press machine with a pneumatic die cushion. FIG. 7 is a diagram schematically illustrating an example of a power conversion system according to a second embodiment. FIG. 13 is a diagram schematically illustrating an example of a power conversion system according to a third embodiment. It is a figure which illustrates typically the structure of the press machine with a servo die cushion which concerns on 3rd Example. FIG. 13 is a diagram schematically illustrating an example of a power conversion system according to a fourth embodiment. FIG. 13 is a diagram schematically illustrating an example of a power conversion system according to a fifth embodiment. FIG. 14 is a diagram schematically illustrating an example of a power conversion system according to a sixth embodiment.

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

First, the basic principle of the power conversion system according to the present embodiment will be described.

FIG. 1 is a diagram schematically showing the overall configuration of the power conversion system according to the present embodiment.

The power conversion system according to the present embodiment controls the operation of the motor 3 by converting the power supplied from the power supply 11 to the motor 3, and includes a power supply device 1 and a motor power conversion device 2 (power conversion device). ). The power supply device 1 includes a forward converter 4 for converting power supplied by an AC voltage from a power supply 11 to a DC voltage VPN, and a step-up / step-down power supply circuit for controlling a voltage VPN of the power converted to a DC voltage by the forward converter 4. 5 and the electric power controlled by the step-up / step-down power supply circuit 5 is supplied to the motor power converter 2 while being accumulated, and the electric power generated by the regenerative operation of the motor 3 and supplied through the motor power converter 2 is It includes a storage device 6 (for example, a capacitor, a storage battery, etc.) for storing, and a voltage command calculation circuit 15 for controlling the operation of the step-up / step-down power supply circuit 5 to control the voltage VPN. The motor power converter 2 controls the operation of the motor 3 by converting the power supplied from the step-up / step-down power supply circuit 5 of the power supply 1 via the storage device 6 and supplying the converted power to the motor 3. 3 that controls the operation of the inverter 7 (power converter) that supplies the power generated by the regenerative operation to the storage device 6 of the power supply device 1 and that is provided in the motor 3. The angular velocity of the motor 3 obtained through the encoder 10 and the torque of the motor 3 calculated based on a current value detected by a current detector (current detecting unit) provided in the motor 3 are set in advance. A control circuit 8 (control unit) for calculating stored energy, which is energy stored in the motor 3 and a motor load 120 driven by the motor 3, based on the moment about the motor 3; The step-up / step-down power supply circuit 5 is controlled on the basis of the stored energy calculated by the path 8 and the maximum amount of power that is allowed to be stored in the storage device 6 in advance. A voltage command calculation circuit for controlling the amount of power stored in the device; Here, the step-up / step-down power supply circuit 5 and the voltage command calculation circuit 15 constitute a power storage device control circuit that controls the amount of power stored in the storage device 6 from the power source 11 based on the stored energy and the maximum power amount. I have.

At this time, considering a rotary drive type motor 3 composed of an AC motor 9 and an encoder 10, the output shaft of the motor 3 rotates and its rotational energy is stored on the load side (motor load 120) including the motor shaft. Can be In addition, when considering a motor 3 such as a linear motor, a movable portion loaded with a load moves on a straight line, and kinetic energy is stored in the load side and the movable portion (motor load 120).

Except for a load in which the rotation angle of the motor 3 moves only a small angle (for example, 10 ° or less) or a special load that moves only a small distance (10 mm or less) on a straight line, an electronic component assembling machine or a semiconductor / liquid crystal manufacturing apparatus In general industrial machines such as metal machine tools, metal working machines, transfer machines, and industrial robots, when a load-side object moves, rotation or kinetic energy is accumulated in the object.

加 Assuming that the moment of inertia of the rotating object is J and the angular velocity of rotation of the output shaft of the motor is ω (rad / s), the acceleration / deceleration torque Tα is represented by the following (Equation 1).

Further, when the crankshaft is connected to the output shaft of the motor to change the rotational motion into a reciprocating motion, and the operation of pressing and returning to the load having the spring characteristic is repeated, the motor load torque including during acceleration / deceleration is calculated by Tq (N · m ), The elastic load torque Td with respect to the spring characteristics is expressed by the following (Equation 2). The friction load, rolling friction, and other loads at this time are assumed to be negligibly small.

慣 In addition, the inertial load power Pα during the generation of the acceleration / deceleration torque in the above (Equation 1) is expressed by the following (Equation 3), where the rotation speed is N (min ＾ (-1)).

弾性 Next, the elastic load power Pd during the constant angular velocity operation is expressed by the following (Equation 4).

Here, when the vehicle is operated with the power Pα given by the above (Equation 3), the inertial load accumulated energy accumulated in the inertial load is expressed by the following (Equation 5) by integrating the above (Equation 3) with time.

Similarly, when operating with the power Pd given by the above (Equation 4), the elastic load storage energy accumulated in the elastic load is expressed by the following (Equation 6) by integrating the above (Equation 4) with time.

Therefore, the total load storage energy E obtained by adding the inertial load storage energy Eα and the elastic load storage energy Ed is represented by the following (Equation 7).

When the motor 3 is decelerated and stopped from this state, the energy stored in the inertial load or the elastic load (or the gravitational load) is regenerated as energy from the motor load 120 via the motor 3 and the inverter 7, such as an electrolytic capacitor or the like. The process returns to the storage device 6 such as a storage battery. At this time, the amount of energy stored in the inertial load or the load side is calculated every moment from the start of operation of the motor 3 so that the storage device 6 does not become overcharged, and the amount of energy stored in the storage device 6 is calculated from the amount of energy stored in the storage device 6. The control circuit 8 controls the voltage command operation circuit 15 by controlling the voltage command operation circuit 15 so that the amount of energy generated by the regeneration is reduced to a specified amount even when the energy generated by the regeneration is stored in the storage device 6. The accumulation amount is variably controlled.

The inertia load or the amount of energy stored on the load side is not calculated from physical power, but a control signal detected from the motor 3 or a sensor provided for driving the motor 3 is used. This is because the moment of inertia and elastic load characteristics (or gravitational load characteristics) can be accurately obtained from the current, voltage, position, speed, angular speed, power, and energy of the motor 3. For example, in the case of an elastic load, the spring characteristics and the like using the restoring force of the compressed air have a durable life, and the characteristics are deteriorated by the life. However, also in this case, the load characteristics according to the aging can be faithfully picked up by the motor 3 and the sensor configured to drive it. Conversely, if it is attempted to operate from the physical power by operating the spring characteristics with the initial constants, the actual characteristics and the dissociated state will be calculated. May occur.

From the law of energy conservation, the appropriate energy amount Eref stored in the storage device 6 is expressed by the following (Equation 8), where the energy stored when the storage device 6 is fully charged is Emax (J).

For example, in the case where an electrolytic capacitor having a capacitance C (F) is used as the storage device 6, if the appropriate voltage of the electrolytic capacitor is Vref (V), the appropriate energy stored in the electrolytic capacitor is represented by the following (Equation 9). .

代入 Substituting the above (Equation 9) into the above (Equation 8) and rearranging, the appropriate voltage Vref of the electrolytic capacitor of the storage device 6 at the time of elastic load is expressed by the following (Equation 10).

Here, the constant k in the above (Equation 10) is represented by the following (Equation 11).

Next, regarding the gravitational load, torque, power, and stored energy are considered in the same manner as the elastic load. The acceleration / deceleration torque under a gravity load is as shown in the above (Equation 1). As the gravity load, for example, a case in which a hoist is connected to the output shaft of the motor 3 and a car or luggage is hung at the tip of a rope, and the hoist is moved up and down can be considered.

、 If the motor torque including during acceleration / deceleration is Tq (N · m), the gravity load torque Tw is represented by the following (Equation 12). The friction load, rolling friction, and other loads at this time are assumed to be negligibly small.

Next, the gravitational load power Pw during the constant angular velocity operation is expressed by the following (Equation 13).

運転 When operated with the gravitational load power Pw given by the above (Equation 13), the gravitational load accumulated energy accumulated in the gravitational load is expressed by the following (Equation 14) by integrating the above (Equation 13) with time.

Therefore, the total load storage energy E obtained by adding the inertial load storage energy Eα and the gravity load storage energy Ew is expressed by the following (Equation 15).

Next, in the case of a gravitational load, the appropriate energy amount Eref stored in the storage device 6 is expressed by the following (Equation 16), where the energy stored when the storage device 6 is fully charged is Emax (J).

Further, for example, when an electrolytic capacitor having a capacitance C (F) is used as the storage device 6, the appropriate energy stored in the electrolytic capacitor is expressed by the above (Equation 9). By substituting into (Equation 16) and rearranging, the appropriate voltage Vref of the electrolytic capacitor of the storage device 6 at the time of gravity load is expressed by the following (Equation 17). Note that the proportional constant k is represented by the above (Equation 11).

Here, when the inertia load energy Eα, the elastic load energy Ed, and the gravitational load energy Ew are regenerated, when the regenerative energy returns from the load side to the storage device 6 via the motor 3 and the inverter 7, the regenerative efficiency is 100%. Some are lost as they are not. Therefore, in the calculation at the time of the regeneration, the inertia load energy Eα, the elastic load energy Ed, and the gravitational load energy Ew are each multiplied by the regeneration efficiency X1 (<1) to reflect the regeneration efficiency. By setting = 1, the regenerative efficiency X1 (<1) is set only at the time of regeneration, so that more accurate control can be realized.

For example, when considering an elastic load using the restoring force of the compressed air as the motor load 120, when the slide descends the compressed air to store energy in the load, and then when the slide starts to rise, the slide is regenerated by the rising speed. The amount of energy is different. This causes a restoring time for the material wrapping the compressed air, so that if the slide is released first, the motor will not be in a regenerative state because there is no reaction force from the elastic load. In fact, regenerative energy is generated because the slide does not actually leave the material surrounding the compressed air. However, the amount of power energy when the slide descends and the amount of regenerative energy when the slide rises are not equal, and the amount of energy on the regenerative side is small. In this case, the amount of energy stored on the load side at the start of operation of the motor is calculated every moment, the amount is subtracted from the amount of energy stored in the storage device, and the state where the amount of energy does not return to the specified amount of energy when regenerated is generated. I do. Therefore, in this case, the energy during power running is multiplied by the weight coefficient X2 (≠ 1) in accordance with the energy amount during regeneration. For example, at the start of operation, the amount of energy stored in the storage device 6 is corrected by performing (the amount of energy stored on the load side) × (weight coefficient X2), and the amount is subtracted. If the amount of energy regenerated is multiplied by (weight coefficient X2) (where X2 = 1) and returned as it is, the deducted amount returns to the original value.

The regenerative efficiency X1 at the time of regeneration (however, X1 <1, at the time of regeneration: X1 = 1 at the time of power running) and the weighting factor X2 at the time of power running (however, X2 ≠ 1 at the time of power running, X2 = 1 at the time of regeneration) are coefficients X. Are summarized in the following (Equation 18).

Here, the proper voltage Vref of the storage device 6 (electrolytic capacitor) under the elastic load shown in the above (Equation 10) and the appropriate voltage Vref of the storage device 6 (electrolytic capacitor) under the gravitational load shown in the above (Formula 17) The voltage Vref is expressed by the following (Equation 19) and the following (Equation 20) using the coefficient X of the above (Equation 18).

In the above (Equation 18), the weighting factor X2 is set such that X2 ≠ 1 during power running and X2 = 1 during regeneration. However, the weighting factor X2 ≠ 1 during regeneration and the weighting factor X2 = 1 during power running. May be set as follows.

As described above, in the case of the elastic load and the gravitational load, the inertial load occurs in common to both loads, and the appropriate voltage Vref of the storage device (electrolytic capacitor) is determined in advance by the above (Equation 19) and (Equation 20). From the start of operation, the amount of energy stored in the inertial load or the load side is calculated every moment, the amount is subtracted from the amount of energy stored in the storage device, and the amount of energy is returned to the specified amount of energy when regenerated. What is necessary is just to variably control the DC voltage of the storage device.

Here, the inertial load, the elastic load, the gravitational load, and the like will be described in detail with specific examples.

FIG. 2 is a diagram illustrating rotation or kinetic energy stored in an inertial load.

(2) As shown in FIG. 2, when electric energy is applied to the inertial body for a time ta by a motor or the like, rotational energy rotating at an angular velocity ω is applied to the inertial body. Here, ignoring losses such as electric paths, rolling friction, and windage, the inertial body continues to rotate forever even when the supply of electric energy is stopped. However, since the loss cannot be ignored in practice, the energy corresponding to the loss must be continuously provided as electric energy in order to maintain the rotation of the inertial body. Next, when the regenerative braking is applied to the inertial body for a time period of td to remove the rotational energy, the inertial body stops, the rotational energy is regenerated, and returns to the power source as electric energy. In other words, turning the inertial load converts the electric energy supplied from the power supply into rotational energy, and stopping the inertial load by the regenerative brake changes the rotational energy into electric energy again. Yes, these can be said to be the act of transferring energy storage locations.

FIG. 2 shows the rotational movement of the crankshaft of the crank press as an example of the rotational movement. The slide mass is shown collectively at point A, and the mass point equivalently showing the balance mass by the balance adjustment is shown at point B. This is schematically shown as the rotational movement of the flywheel shown. The energy E stored in such an inertial body is represented by the following (Equation 21), where the angular velocity of the crankshaft is ω (rad / s) and the moment of inertia of the inertial body is J (kg · m ＾ 2). Is proportional to the moment of inertia J and proportional to the square of the angular velocity ω.

As shown in FIG. 2, in the case of linear motion, the energy E stored as kinetic energy is represented by the following (Equation 22), where m (kg) is the mass of the inertial body and Vl is the moving speed. It can be seen that it is proportional to m and proportional to the square of the moving speed Vl (m / s).

FIG. 3 is a diagram schematically illustrating the structure of a press machine with a pneumatic die cushion.

In FIG. 3, the press machine has a slide 25 that moves up and down and a bolster 27 that is fixed. The slide 25 moves up and down while the rotation of the slide motor 20 is guided by the slide gib 26 through the slide drive means 21 and the crank mechanism (the crankshaft 22 and the crank eccentric part 23). The bolster 27 is fixed on a bed 28, is connected to a slide mechanism through a frame of a press machine, and has a structure to receive a pressing force from above. As an example of the slide driving means 21, in the case of a crank press that is used most often, the rotation of the slide motor 20 is transmitted from the crankshaft 22 to the crank eccentric part 23, and the slide 25 is moved up and down via the connection rod 24. A press is performed by attaching a die to this press machine. The upper mold 29 is set on the lower surface of the slide 25, and the lower mold 30 is set on the upper surface of the bolster 27, and a pair of upper and lower parts constitutes one mold. The mold can perform processing such as shearing, bending, and squeezing an iron plate or the like, and can give a desired shape by giving plastic deformation to the iron plate. The quality and performance of this mold play an important role in the productivity and quality of press working. In the drawing process of the pneumatic die cushion device 31, for example, in the case of cup-shaped drawing, a compressive stress in the circumferential direction is generated in a flange portion of a molded product as the process proceeds, and wrinkles are generated if left unattended. The pneumatic die cushion device 31 generates a necessary wrinkle holding pressure from below so as not to generate the wrinkles. The pneumatic die cushion device 31 is built in the bed 28, and the lower die 30 and the die cushion pad (not shown) and the die cushion pin (not shown) operate in conjunction with each other. The pneumatic die cushion device 31 includes a servo die cushion using a servo motor in addition to a pneumatic type and a hydraulic type.

FIG. 4 is a diagram for explaining the energy stored in the pneumatic die cushion.

(4) As shown in FIG. 4, the die cushion is a pressure holding device that generates a reaction force for holding down wrinkles in drawing and a pushing force of a molded product. A pneumatic die cushion is equivalently replaced by an air spring. As the spring deforms, energy is stored in the spring in the form of elastic energy. Release of the stored energy allows the spring to perform mechanical work. An air spring, which is a material for generating a restoring force of air, is also a kind and is used in a pneumatic die cushion.

When energy is stored in the pneumatic die cushion device 31, the air in the pneumatic die cushion is compressed by moving the slide 25 in the downward direction, and elastic energy is stored in this part, and at the same time, the reaction force in the sliding direction is reduced. appear. The lower the slide 25 is pressed, the greater the reaction force 31E is. Therefore, the reaction force 31E can be replaced with a spring having a spring constant k (N / m). m), the stored elastic energy E is given by the following (Equation 23).

FIG. 5 is a diagram illustrating the energy stored in the lifting device.

As shown in FIG. 5, in a lifting device 82 (described later), a hoist 76 is connected to a motor output shaft, and a load (or a basket for storing a load or the like) 77 is hung above a rope 78 to perform a lifting operation. . In FIG. 5, when a load 77 having a mass m (kg) is on the ground, the energy is in an open state. When the load 77 is wound up to the height h (m) from this state, the potential energy mgh (J) is stored. When the load 77 rises, the motor operates in a power running state because it moves in the direction opposite to the direction of gravity acting on the load 77, and potential energy is stored in the load 77. Further, when the load 77 is lowered, the load 77 is lowered while suppressing the drop of the load 77 due to gravity. Therefore, the motor operates in a regenerative state, and the potential energy stored in the load 77 is released.

FIG. 6 is a diagram illustrating the relationship between the crankshaft angular speed and the slide speed of the crank press.

FIG. 6 shows a case where the crankshaft is rotated 360 ° (one rotation) from the top dead center to the top dead center via the bottom dead center in the rotation direction, and the horizontal axis represents time t (s). The vertical axis indicates the crankshaft angular velocity ω (rad / s), the slide position θs (mm), and the slide velocity Vs (m / s). The slide speed Vs becomes zero speed when the slide position is at the intermediate point, and the positive side of the slide speed indicates the ascending speed and the negative side indicates the descending speed. In FIG. 6, the slide position is a cosine curve, but the slide speed is a sine curve with a 180 ° phase delay because the connection point of the connecting rod of the crankshaft rotates.

The operation and effect of the present embodiment configured as described above will be described.

The prior art includes a low-cost, low-loss, and high-density power supply device by variably setting a control command value of a storage device based on rotational energy or spring energy stored in a motor and a motor load. This conventional technique is effective for a power supply device that variably controls the voltage of a storage device for energy stored in an inertial load. However, the energy stored other than the inertial load is not specifically shown, and the energy stored in the elastic load such as a spring is not clear.

Further, in another conventional technique, in a servo press apparatus having a slide variably driven by an AC motor, a control pattern for controlling a charge / discharge state of an energy storage device is selected based on an operation pattern of the press machine, and a power supply is selected. There are techniques for reducing the size and efficiency of the converter and optimizing the capacity of the energy storage device. This prior art is a system in which an operation pattern of a press machine and a control pattern for controlling a charge / discharge state of an energy storage device based on the operation pattern are registered in advance, and an operation command is given in synchronization with the operation pattern. It is valid. However, there has been a problem that a method of responding to an operation command synchronized with an operation pattern and a control pattern in the case of an independent setting device or an operation command set each time is not clear.

Further, another related art relates to a technology related to abnormal processing and display of a regenerative braking state by consuming the regenerated energy in a resistor of a regenerative braking circuit in an inverter in which an AC power supply is rectified and converted to a fixed DC voltage. There is. This prior art is effective for abnormal processing and display of a regenerative braking state of an inverter in which an AC power supply is set to a fixed DC voltage by a rectifier circuit. However, since the regenerated energy is consumed by the resistor of the regenerative braking circuit, there has been a problem about environmental improvement against global warming.

With respect to such a problem in the related art, according to the present embodiment, it is possible to distinguish whether the load during operation is an inertial load or an elastic load, or to distinguish an inertial load or a gravitational load. In the case of an elastic load that generates a reaction force, the amount of power stored in the storage device is variably controlled with respect to the case of a gravitational load that moves up and down, so that excessive storage of power in the storage device is prevented. Thus, power loss can be reduced and the size of the storage device can be reduced. In addition, an operation pattern of the press machine as a load and a control pattern for controlling a charge / discharge state of the energy storage device based on the operation pattern may be registered in advance, or an operation command may be given in synchronization with the operation pattern. unnecessary. Further, it is not necessary to consume the regenerated energy by the resistor of the regenerative braking circuit.

That is, in the present embodiment, when the load of the motor 3 is applied to the inertial load, the elastic load, and the gravitational load, energy is stored on the load side at the same time as the operation, and the electric power having the storage device 6 on the input side of the inverter 7. In the conversion system, the speed and current of the motor 3 are detected by a detector together with the operation of the motor 3 to calculate the amount E of energy stored on the load side, and the energy command value stored in the storage device 6 is Eref, when the battery is fully charged. If the energy of the storage device 6 is Emax, the energy stored in the storage device 6 is optimized by calculating the energy command value Eref = (Emax−E) stored in the storage device 6, and the power conversion system , High efficiency, and low cost can be realized.

A first embodiment of the present invention will be described with reference to FIGS.

FIG. 7 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In this embodiment, a case where the motor is driven by using a press machine with a pneumatic die cushion as a load is exemplified.

In FIG. 7, the power conversion system controls the operation of the motor 3 by converting the power supplied from the power supply 11 to the motor 3, and is roughly composed of a power supply device 1 and a motor power conversion device 2. ing.

The power supply device 1 includes a forward converter 4 for converting power supplied by an AC voltage from a power supply 11 to a DC voltage VPN, and a step-up / step-down power supply circuit for controlling a voltage VPN of the power converted to a DC voltage by the forward converter 4. 5 and the electric power controlled by the step-up / step-down power supply circuit 5 is supplied to the motor power converter 2 while being accumulated, and the electric power generated by the regenerative operation of the motor 3 and supplied through the motor power converter 2 is It includes a storage device 6 (for example, a capacitor, a storage battery, etc.) for storing, and a voltage command calculation circuit 15 for controlling the operation of the step-up / step-down power supply circuit 5 to control the voltage VPN. Here, the step-up / step-down power supply circuit 5 and the voltage command calculation circuit 15 constitute a power storage device control circuit that controls the amount of power stored in the storage device 6 from the power source 11 based on the stored energy and the maximum power amount. I have.

The motor power conversion device 2 controls the operation of the motor 3 by converting the power supplied from the step-up / step-down power supply circuit 5 of the power supply device 1 via the storage device 6 and supplying the converted power to the motor 3. An inverter (inverter) 7 that supplies the power generated by the regenerative operation to the storage device 6 of the power supply device 1 and an inverter 7 that controls the operation of the inverter 7 and that is obtained through an encoder 10 provided in the motor 3. And the torque of the motor 3 calculated based on the angular velocity of the motor 3, the current value detected by current detectors 59 and 60 (described later) provided in the motor 3, and the moment of inertia of the motor 3 set in advance. Based on the above, the stored energy which is the energy stored in the motor 3 and the motor load driven by the motor 3 (here, the press machine 12 with a pneumatic die cushion) is calculated. The step-up / step-down power supply circuit 5 is controlled based on the control circuit 8, the stored energy calculated by the control circuit 8, and the maximum amount of power that is allowed to be stored in the storage device 6. A voltage command calculation circuit 15 for controlling the amount of power stored in the storage device 6 from the power supply 11; The control circuit 8 generates a gate signal based on the detection results from the

current detectors

59 and 60 of the inverter 7 and the encoder 10 of the motor 3, and controls the inverter 7 with the gate signal to control the motor 3 Speed control circuit 16 for controlling the driving of the motor 3 and calculating the angular velocity and torque of the motor 3, and a press machine 12 with a pneumatic die cushion as a motor load based on the calculation result of the position / speed current control circuit 16. And a stored energy calculation circuit 14 (calculation circuit) for calculating stored energy.

モータ The motor 3 for driving the slide 25 of the press machine 12 with a pneumatic die cushion (hereinafter sometimes simply referred to as the press machine 12) is composed of an AC motor 9 and an encoder 10 provided on the AC motor 9. The speed, position, and magnetic pole position of the AC motor 9 are detected by the encoder 10 and fed back to the position / speed / current control circuit 16 of the control circuit 8 of the motor power converter 2. In the position / speed current control circuit 16, a signal (speed, position, magnetic pole position) fed back from the encoder 10 is compared with a motor drive command from the host device 13, and the slide of the press machine 12 driven by the motor 3 is performed. A PWM signal is generated and output to the inverter 7 so that the inverter 25 follows the motor drive command. The inverter 7 receives a DC voltage (inter-PN voltage) supplied from the power supply device 1 and converts the DC voltage into a variable AC voltage and a variable current to drive the AC motor 9. Control the current. The current of the AC motor 9 is detected by current detectors 59 and 60 (described later) in the inverter 7 and fed back to the position / velocity current control circuit 16 to be used for calculation of torque and the like.

The power supply device 1 receives AC power from the power supply 11, converts the AC power into DC voltage by the forward converter 4, and inputs the DC voltage to the buck-boost power supply circuit 5. The step-up / step-down power supply circuit 5 supplies the variable DC voltage to the inverter 7 by performing step-up, step-down, or step-up / step-down of the DC voltage. The step-up / step-down power supply circuit 5 is controlled by a voltage command operation circuit 15. The voltage command calculation circuit 15 receives the signal E calculated by the control circuit 8 of the motor power conversion device 2 and performs variable voltage control on the step-up / step-down power supply circuit 5 so that the DC voltage VPN of the storage device 6 becomes an optimum voltage. I do. The storage device 6 is provided between the step-up / step-down power supply circuit 5 and the inverter 7. The storage device 6 receives electric energy from the power source 11, the press machine 12 via the motor 3, the inverter 7, and the like. The supplied regenerative energy is stored.

Next, the outline of the control operation of the entire power conversion system will be described. First, the energy stored in the inertial load of the press machine 12 will be described. When a motor drive command is given from the host device 13, the motor 3 starts moving up and down the slide 25 according to the command. When the slide 25 starts the vertical movement, the amount of energy of the inertial load stored in the moment of inertia including the motor 3 and a mechanism connected to the load is calculated in real time. In addition, when the slide 25 and the pneumatic die cushion device 31 both start up / down operation, the amount of energy of the inertial load stored in the moment of inertia including up to the pneumatic die cushion device 31 is calculated in real time. Next, even when the regenerative energy returns when the regeneration is stopped, the storage capacity of the storage device 6 must be prevented from overflowing. Therefore, control is performed so that the capacity of the energy stored in the storage device 6 is reduced at the same time as the movement starts. In this controlled state, a regeneration stop command is received from the host device 13 as a motor drive command, and even if the regenerative energy actually returns, the level returns to the level of the original energy state before the start of operation. Will not be overcharged.

Note that the above-described stored energy calculation is performed by the stored energy calculation circuit 14 in the control circuit 8 of the motor power conversion device 2, and the control of the optimum value of the energy capacity of the storage device 6 is performed by the PN that is replaced by the voltage of the storage device 6. The voltage command operation circuit 15 of the power supply device 1 performs the operation as the inter-voltage command Vref.

Next, detailed operations of the stored energy calculation circuit 14 of the motor power conversion device 2 and the voltage command calculation circuit 15 of the power supply device 1 will be described. The signals input from the position / velocity current control circuit 16 are an angular velocity detection signal ω, a torque detection signal Tq, and a moment of inertia J detected by the encoder 10. First, the energy stored in the inertial load will be described. The acceleration / deceleration torque Tα of the angular velocity signal ω of the motor 3 is calculated by the acceleration / deceleration torque calculation circuit 42 by the calculation of the above (Equation 1). The output Tα of the acceleration / deceleration torque calculation circuit 42 calculates the product of the angular velocity signal ω and the acceleration / deceleration power calculation circuit 43 (Equation 3) to output the acceleration / deceleration power Pα. Acceleration / deceleration power Pα is subjected to time integration calculation by the above-mentioned (Equation 5) in inertial load accumulated energy calculation circuit 44 to output inertia load accumulated energy Eα. The acceleration / deceleration power calculation circuit 43 and the inertial load storage energy calculation circuit 44 are referred to as an inertia load storage energy calculation block 40.

Next, the energy stored in the elastic load will be described. The difference between the torque detection signal Tq and the output Tα of the acceleration / deceleration torque calculation circuit 42 is calculated by the addition / subtraction calculator 51 as shown in the above (Equation 2), and the elastic load torque Td is output. The elastic load power calculating circuit 45 calculates the product of the above equation (4) from the elastic load torque Td and the angular velocity signal ω to output the elastic load power Pd. The elastic load power Pd is subjected to time integration calculation by the above-mentioned (Equation 6) in the elastic load accumulated energy calculation circuit 46, and the elastic load accumulated energy Ed is output. The elastic load power calculating circuit 45 and the elastic load accumulated energy calculating circuit 46 are referred to as an elastic load accumulated energy calculating block 41.

The signals input to the inertial load stored energy calculation circuit 44 and the elastic load stored energy calculation circuit 46 include CLR1 and CLR2 output from the position / velocity current control circuit 16. The integration clear signals CLR1 and CLR2 are signals for clearing the output of the integration operation circuit, that is, the inertial load accumulated energy operation circuit 44 or the elastic load accumulated energy operation circuit 46. Further, the position / speed current control circuit 16 outputs the total value J of the rotor inertia moment of the AC motor 9 and the load-side inertia moment of the motor 3 converted into the motor shaft to the acceleration / deceleration torque calculation circuit 42.

The output Eα of the inertial load storage energy calculation block 40 and the output Ed of the elastic load storage energy calculation block 41 are subjected to the addition calculation of the above (Equation 7) by the addition calculator 50, and the result is sent to the voltage command calculation circuit 15 of the power supply device 1. It is output as the total load accumulated energy E. In the voltage command calculation circuit 15 of the power supply device 1, the value Emax is set as the energy when the storage device 6 is fully charged in the full charge energy setting block 47. The difference from the total load accumulated energy E output from the accumulated energy calculation circuit 14 of FIG. 2, that is, the appropriate energy Eref stored in the storage device 6 is derived by the above (Equation 8).

Here, for example, when the electrolytic capacitor C is used as the storage device 6, after multiplying Eref, which is the output of the addition / subtraction operation unit 51, by k = 2 / C expressed by the above (Equation 11) in the proportional coefficient block, When the square root operation is performed by the square root operation circuit 49, the voltage command Vref for the storage device 6 shown in the above (Equation 10) is obtained. Further, the voltage VPN (voltage between PN) across the storage device 6 is divided by a resistor 56 (described later) having a resistance value R1 and a resistor 57 (described later) having a resistance value R2 which are connected in series, and a detection value (feedback) is obtained. The voltage is detected as voltage Vf, and is fed back after the insulation amplifier 18 performs electrical insulation. After that, the voltage command Vref of the storage device 6 and the feedback voltage Vf are subjected to a difference calculation of Vref−Vf by the addition / subtraction calculator 51. This difference voltage is proportionally integrated by the PI adjuster 17, and the inverter 7 is controlled via the drive circuit 61 (described later) of the position / velocity current control circuit 16, whereby the output voltage of the step-up / step-down power supply circuit 5 is controlled. The feedback control of the VPN, that is, the output voltage of the storage device 6 is performed according to the value of the voltage command Vref.

FIG. 8 is a diagram showing an example of the details of a directional converter, a step-up / step-down power supply circuit, and a storage device of a power supply device, and shows a case where a circuit performing a boosting operation is used as the step-up / step-down power supply circuit.

That is, it can be said that the step-up / step-down power supply circuit 5 in FIG. 8 is a step-up power supply circuit showing a step-up operation.

The forward converter 4 rectifies the AC voltage supplied from the AC power supply 11 by the full-wave rectifier 55, converts the AC voltage to a substantially constant DC voltage determined by the received voltage, and smoothes the DC voltage by the smoothing capacitor 52. The smoothed DC voltage is connected to a switching element 53 which repeats ON / OFF via a step-up reactor 58 in a step-up / step-down power supply circuit 5 which is a step-up power supply circuit. When the switching element 53 is turned on, the current flowing through the boosting reactor 58 increases. When the switching element is turned off next, the current flowing from the boosting reactor 58 to the switching element 53 is switched to the diode 54 side, and the output voltage VPN has a direct current. Voltage e = −L · (dI / dt) generated at both ends of boost reactor 58 is added to the voltage (voltage between P0 and N) and boosted. The switching element 53 is repeatedly turned on / off, and the step-up / step-down power supply circuit 5 is configured such that the step-up voltage can be variably controlled by changing the conduction ratio. A smoothing capacitor 52 is connected to the output of the step-up / step-down power supply circuit 5 as a storage device 6 to store electric energy charged from the AC power supply 11 and regenerative energy regenerated from the load side. Although the smoothing capacitor 52 is used in the storage device 6 in FIG. 8, a large-capacity electrolytic capacitor is connected in parallel to increase the capacity, but a secondary battery, an electric double layer capacitor, or the like may be used. good.

FIG. 9 is a diagram showing another example of the details of the forward converter, the step-up / step-down power supply circuit, and the storage device of the power supply device, and shows a case where a circuit that performs a step-down operation is used as the step-up / step-down power supply circuit.

That is, it can be said that the step-up / step-down power supply circuit 5A in FIG. 9 is a step-down power supply circuit showing a step-down operation.

The forward converter 4 rectifies the AC voltage supplied from the AC power supply 11 by the full-wave rectifier 55, converts the AC voltage to a substantially constant DC voltage determined by the received voltage, and smoothes the DC voltage by the smoothing capacitor 52. Next, a switching element 53 that repeats ON / OFF is provided at the entrance, and when the switching element 53 is turned ON, the voltage is given because the step-down reactor 58A and the load are connected in series, and the voltage is reduced by changing the ON / OFF conduction ratio. A step-up / step-down power supply circuit 5A that operates as a step-down power supply circuit capable of variably controlling the voltage is configured. A smoothing capacitor 52 is connected to the storage device 6 at the output, and electric energy charged from the AC power supply 11 and regenerative energy regenerated from the load side are stored. The increase in the capacity of the smoothing capacitor 52 is the same as in FIG.

FIG. 10 is a diagram showing details of the inverter and the position / velocity current control circuit of the motor power converter.

In FIG. 10, an AC servo amplifier, a vector control inverter, an inverter, and a DCBL controller are used as the motor power converter 2, and these are collectively referred to as the motor power converter 2.

The inverter 7 has one arm in which two sets of an anti-parallel circuit of the switching element 53 and the diode 54 are connected in series, and these three arms are connected in parallel to form a three-phase inverter. Although FIG. 10 illustrates a case where a three-phase inverter is configured, another multi-phase inverter may be configured. An intermediate terminal of each arm is connected to a motor terminal of the motor 3, and a U-phase current detector 59 and a W-phase current detector 60 are respectively connected to two phases (U-phase and W-phase). The U-phase current detector 59 and the W-phase current detector 60 may be simply referred to as the

current detectors

59 and 60 in some cases.

(4) As the AC motor 9, a permanent magnet motor, an induction motor, a DC brushless motor (DCBL motor), or the like is used. Note that the AC motor has a shaft at the center of the cylindrical shape, and is not caught by only a permanent magnet type motor or an induction type motor in which this shaft rotates. For example, a linear motor may be used in which a portion of the circumference of the AC motor 9 on the stator side is cut open to form a straight line, and the rotating portion has a linear reciprocating motion. As the AC servo amplifier for driving the linear motor, the vector control inverter, the inverter, and the DCBL controller, the AC motor 9 can be used as it is. In the case of a linear motor, the sensor is provided with a linear sensor scale on a fixed part and a linear sensor head on a moving part, instead of the encoder 10, on the moving path, and detects the position and speed. If a magnetic pole position detection signal of the magnet is required, it can be dealt with by attaching a magnetic pole position detection sensor. The linear motor driven by the AC servo amplifier is also called a linear servo motor. In the following description, the AC motor 9 includes a linear motor unless otherwise specified.

The output of the encoder 10 attached to the output shaft of the AC motor 9 is input to the position / velocity magnetic pole position calculation circuit 62, and the rotation speed N which is one of the calculation results is output to feedback, and the other one of the calculation results is used. Is output to the three-phase / dq conversion circuit 68 and the dq / 3-phase conversion circuit 66.

The rotational speed N is such that the speed command Ns among the motor drive commands output from the host device 13 passes through the mode switch 74 (Mod2), and the addition / subtraction calculator 51 calculates the deviation ε = Ns−N. The deviation ε is amplified by the speed control circuit (ASR) 63, passes through the mode switch (Mod1), and is output as a torque current command Iq. The mode switch 73 (Mod1) switches the motor drive command to the torque command Ts when turned on, and switches to the position command or speed command when turned off. The mode switch 74 (Mod2) switches the motor drive command to the position command θs when turned on, and switches to the speed command Ns when turned off. It should be noted that which mode the motor drive command is switched to is instructed from the host device 13 to the CPU 72 of the position / speed / current control circuit 16 of the motor power converter 2 and the CPU 72 switches the mode. That is, the CPU 72 not only controls the outputs of the integration clear signals CLR1 and CLR2, but also controls the operation of the entire unit 16 based on a command from the host device 13.

The detection results of the

current detectors

59 and 60 are input to the three-phase / dq conversion circuit 68 as current feedback signals Iuf and Iwf of the AC motor 9, and are d-axis current negative feedback signals, which are two vector signals whose dq axes are orthogonal to each other. It is converted into Idf and a torque current feedback signal Iqf. The torque current command Iq is input to an addition / subtraction calculator 51 for calculating a difference from the torque current feedback signal Iqf, and the difference is amplified by a q-axis current control circuit (ACR) 65. The d-axis current command Id is a current command for performing field-weakening control, and is input to an addition / subtraction calculator 51 that calculates a difference from the d-axis current negative feedback signal Idf, and the deviation is used as a d-axis current control circuit (ACR). Amplified at 64. The d-axis current command Vd output from the d-axis current control circuit (ACR) 64 and the q-axis voltage command Vq output from the q-axis current control circuit (ACR) 65 are input to a dq / 3-phase conversion circuit 66. The three-phase voltage commands Vu, Vv, and Vw are converted into three-phase voltage commands and output to the PWM circuit 67, and are output from the PWM circuit 67 as gate signals for driving the six switching elements 53 of the inverter 7 through the drive circuit 61. Thus, the motor 3 is controlled to follow the motor drive command.

Note that the total value J = Jm + Jl of the inertia moment Jm of the AC motor 9 and the load-side inertia moment Jl of the motor 3 converted into the motor shaft is obtained by inputting the calculated inertia moment J into the parameter of the motor power converter 2 at the time of the test operation. Alternatively, tuning can be performed by the auto-tuning function of the moment of inertia J by the test operation function of the motor power conversion device 2. If the motor power converter 2 has a function of tuning the moment of inertia J in real time during operation (a function of real-time auto-tuning), even if the moment of inertia J changes with the function, the value tuned in real time is updated. can do. The CPU 72 of the position / speed current control circuit 16 outputs the moment of inertia J stored and updated in the parameter area 75 by tuning or the like to the acceleration / deceleration torque calculation circuit 42 of the stored energy calculation circuit 14, and the acceleration / deceleration torque calculation circuit 42 The used moment of inertia J can be updated in real time. The values of these parameters are written from the RAM memory to the nonvolatile memory when the power is turned off, and the updated moment of inertia J which is read from the nonvolatile memory to the RAM memory and updated when the power is turned on next time is inherited. .

FIG. 11 is a diagram showing an example of a waveform of an angular velocity detection signal of a slide motor when drawing is performed by a press machine with a pneumatic die cushion.

In the present embodiment, the angular velocity detection signal ω of the slide motor and the torque detection signal Tq are output from the position velocity current control circuit 16. In the drawing process, a blank material is sandwiched between the upper die of the slide 25 and the lower die of the pneumatic die cushion device 31, and the sliding torque from above and the reaction force of the pneumatic die cushion device 31 to push up from below. With this, a compressive force is applied to the blank material from both the upper and lower sides. As shown in FIG. 11, at the beginning of the drawing, the slide 25 starts to descend at a high speed from the top dead center and decelerates to a medium speed just before contacting the pneumatic die cushion device 31. After reaching the middle speed, the drawing process starts, and after passing through the bottom dead center, the slide 25 starts to rise and separates from the pneumatic die cushion device 31, and then the angular velocity detection signal ω accelerates again and stops at the top dead center. I do. Here, the rotation direction of the slide motor (motor 3) is one-way operation, but the operation direction of the slide 25 switches between descending and ascending (see FIG. 6). In FIG. 11, the timing of the drawing process is shown in the range of the arrow as during the drawing process at the middle speed.

FIG. 12 is a diagram showing an example of a waveform of a torque detection signal of a slide motor when drawing is performed by a press machine with a pneumatic die cushion.

As shown in FIG. 12, the slide torque (torque detection signal) Tq when no drawing is performed is such that the acceleration torque is generated on the positive side during acceleration and the deceleration torque is generated on the negative side during deceleration. Acceleration / deceleration torque is generated only when the angular velocity changes. During the drawing process, the slide 25 descends and gradually presses the compressed air of the pneumatic die cushion device 31, so that elastic energy is stored and the torque (torque detection signal Tq) of the slide motor gradually increases in the positive direction. To increase. At the bottom dead center, the pressing torque becomes zero, but the reaction force from the pneumatic die cushion device 31 is received. When passing through the bottom dead center and turning upward, the slide torque (torque detection signal) Tq is switched to the regenerative brake torque in the negative direction because the increased reaction force of the pneumatic die cushion device 31 maintains the medium speed. When the slide 25 separates from the pneumatic die cushion device 31, the stored elastic energy is released and the regenerative torque rapidly decreases to zero. In FIG. 12, a die cushion torque is generated in a portion indicated by the range of the arrow during the drawing process.

FIG. 13 is a diagram showing an example of an output waveform of the acceleration / deceleration torque calculation circuit when drawing is performed by a press machine with a pneumatic die cushion.

The output waveform of the acceleration / deceleration torque calculation circuit 42 is a waveform obtained by differentiating the angular velocity detection signal ω of the slide motor and multiplying by the inertia moment J. Accordingly, as shown in FIG. 13, the output becomes zero when the angular velocity detection signal ω is constant, and no die cushion torque appears during the drawing process because the angular velocity detection signal ω is constant. Therefore, as the output waveform of the acceleration / deceleration torque calculation circuit 42, a waveform obtained by separating only the acceleration / deceleration torque of the slide motor is obtained. Normally, the detection based on the current waveform of the motor 3 includes the entire load current, so that it is impossible to detect only the acceleration / deceleration torque separately. That is, it is one of the features of the present embodiment that only the acceleration / deceleration torque can be separated by the calculation.

FIG. 14 is a diagram showing an example of an output waveform of the addition / subtraction arithmetic unit when drawing is performed by a press machine with a pneumatic die cushion.

出力 The output Td of the addition / subtraction calculator 51 is represented by a torque detection signal Tq−acceleration / deceleration torque Tα. For example, when drawing is performed by the press machine 12 with a pneumatic die cushion, the main torque of the slide motor is acceleration / deceleration torque for accelerating and decelerating the load inertia moment, and drawing is performed by the slide 25 and the pneumatic die cushion device 31. It is almost two of die cushion torque. Generally, the torque components of all the loads applied to the motor 3 appear in the torque detection signal Tq of the motor 3, but since the die cushion torque at the time of drawing is equal to the elastic load torque Td, as shown in FIG. , The elastic load torque Td is calculated by the slide motor torque (torque detection signal) Tq−the acceleration / deceleration torque Tα.

As shown in FIGS. 13 and 14, in the present embodiment, the slide motor torque (torque detection signal) Tq is determined by the acceleration / deceleration torque Tα generated in the inertial load and the elastic load torque Td generated in the elastic load. It has the characteristic that it is detected separately in two.

FIG. 15 is a diagram illustrating an example of an output waveform of the inertial load accumulated energy calculation circuit when drawing is performed by a press machine with a pneumatic die cushion.

The inertial load accumulated energy Eα, which is the output of the inertial load accumulated energy calculation circuit 44, calculates acceleration / deceleration power Pα by multiplying the angular velocity detection signal ω of the slide motor by the acceleration / deceleration torque Tα in the acceleration / deceleration power calculation circuit 43. It is calculated by integrating the acceleration / deceleration power Pα over time. The accumulated inertia load energy Eα whose waveform is shown in FIG. 15 is obtained by accumulating or subtracting the energy only when the angular velocity detection signal ω (see FIG. 11) of the slide motor is changing. Therefore, the angular velocity detection signal ω is constant. It is not integrated during a certain drawing process, that is, when a die cushion torque is generated.

FIG. 16 is a diagram showing an example of an output waveform of the elastic load accumulated energy calculation circuit when drawing is performed by a press machine with a pneumatic die cushion.

The elastic load accumulated energy Ed, which is the output of the elastic load accumulated energy calculating circuit 46, is calculated by multiplying the elastic load torque calculating circuit 45 by the angular velocity ω of the slide motor and the elastic load torque Td. It is calculated by integrating the power Pd over time. The elastic load accumulated energy Ed whose waveform is shown in FIG. 16 has a shape obtained by integrating the waveform of the elastic load torque Td (see FIG. 14) because the angular velocity detection signal ω of the slide motor is constant at the middle speed during the drawing process.

As shown in FIGS. 15 and 16, in the present embodiment, the inertial load accumulated energy Eα stored in the slide motor and its load and the elastic load accumulated energy Ed stored in the pneumatic die cushion device 31 are different from each other. Is calculated individually.

FIG. 17 is a diagram showing an example of an output waveform of the addition calculator of the stored energy calculation circuit when drawing is performed by a press machine with a pneumatic die cushion.

As shown in FIG. 17, the total load accumulated energy E output from the addition calculator 50 is the waveform itself obtained by adding the inertial load accumulated energy Eα (see FIG. 13) and the elastic load accumulated energy Ed (see FIG. 14). It is.

FIG. 18 is a diagram showing an example of an output waveform of the voltage command calculation circuit when drawing is performed by a press machine with a pneumatic die cushion.

The output of the voltage command operation circuit 15 is an output voltage command Vref for controlling the step-up / step-down power supply circuit 5. In the voltage command operation circuit 15, first, in the addition / subtraction operation unit 51, the total load accumulated energy E which is the output of the accumulated energy operation circuit 14 of the control circuit 8 (that is, the output of the addition operation unit 50) is fully charged in the accumulation device 6. It is subtracted from the energy Emax at the time. The energy Emax of the storage device 6 at the time of full charge is the maximum value at the time of full charge, but is a constant value. Then, the energy (J) is replaced by a unit of voltage (V) via the square root operation circuit 49. As a result, as shown in FIG. 18, the output voltage command Vref is obtained as a waveform obtained by subtracting the waveform of the total accumulated energy E (see FIG. 17) from the constant value.

As shown in FIG. 18, in the drawing process, the voltage Vref of the accumulating device 6 is initially changed by the change of the angular velocity detection signal ω from acceleration to high speed to medium speed when the slide motor descends. , The voltage of the storage device 6 is gradually lowered so as to be able to be regenerated immediately, the voltage Vref is maintained when the angular velocity detection value ω is constant, and a part of the energy is lost when the vehicle is decelerated to a medium speed. Since the power is regenerated, the voltage Vref is returned and increased by that amount. During the next drawing, the elastic load energy supplied from the power supply 11 by the pneumatic die cushion device 31 increases, so that the voltage Vref of the storage device 6 is greatly reduced. Further, when the total energy E exceeds the peak, the elastic load energy starts to regenerate, so that the voltage Vref of the storage device 6 returns to an increase this time. Then, when the drawing is completed, the operation shifts to the operation of the inertial load accumulated energy again, and the same operation as in the first high-speed operation is performed at medium speed → high speed → stop.

As shown in FIGS. 11 to 18, in the present embodiment, the voltage command Vref of the storage device 6 is variably controlled according to the energy stored in the inertial load and the energy stored in the elastic load.

A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, only differences from the first embodiment will be described. In the drawings used in the present embodiment, the same members as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the power supply device is incorporated in the motor power converter, and the voltage of the storage device is variably controlled based on the inertial load stored energy.

FIG. 19 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In this embodiment, a storage element 6A is used in place of the storage device 6 of the first embodiment, and an injection molding machine is driven by a motor as a load.

In FIG. 19, the motor power converter 2A of the power conversion system according to the present embodiment includes a forward converter 4, a step-up / step-down power supply circuit 5, a storage element 6A, an inverter 7, a control circuit 8, and a voltage command operation circuit 15. It has. Further, the control circuit 8 includes a stored energy calculation circuit 14A (calculation circuit) and a position / velocity current control circuit 16A.

The stored energy calculation circuit 14A of this embodiment outputs the acceleration / deceleration torque Tα output from the acceleration / deceleration torque calculation circuit 42 and the elastic load torque Td (the output of the addition / subtraction calculator 51) to the position / speed current control circuit 16A. It is configured as follows. Generally, a torque detection signal of a motor includes torque components of all loads applied to the motor. On the other hand, in the present embodiment, the acceleration / deceleration torque Tα generated in the inertial load and the elastic load torque Td generated in the elastic load can be separated from each other. The load torque Td is fed back to the position / speed current control circuit 16A. The position / velocity current control circuit 16A has a function of taking in the acceleration / deceleration torque Tα and the elastic load torque Td from the stored energy calculation circuit 14A, that is, a separate monitor torque function.

(4) The position / speed current control circuit 16A outputs the acquired acceleration / deceleration torque Tα and elastic load torque Td to the host device 13. In the host device 13, the acceleration / deceleration torque Tα and the elastic load torque Td are used for studying what power should be reduced in order to save energy. In other words, it is possible to measure individually by changing various conditions such as whether to reduce the inertial load power, the elastic load power, or the tact time or the elastic load torque. The acceleration / deceleration torque Tα and the elastic load torque Td can be considered.

In FIG. 19, the injection shaft 34 of the injection molding machine 35 is illustrated as a load for general industrial machines. Since the injection shaft 34 as the motor load does not store energy other than the elastic load and the gravitational load except for the inertial load, the elastic load storage energy calculation circuit 46 always turns on the CLR2 of the integration clear signal 2 and sets its output to zero. To disable. However, the inertial load storage energy calculation circuit 44 is enabled to perform the energy storage calculation. The integration clear signals CLR1 and CLR2 can be always set to ON from the outside by using parameters, and can be set to be ON when the load cannot store energy. The ON setting can also be set from the host device 13.

Other configurations are the same as those of the first embodiment.

In the present invention, since the rechargeable energy is not overcharged even when the regenerative energy returns to the power storage device, when the power storage device 6A (for example, an electrolytic capacitor) is used as the power storage device, the voltage preset in the power storage device 6A. By reducing the upper limit margin of the range and raising the upper limit of the voltage range, the energy that can be stored without increasing the capacity of the electrolytic capacitor can be increased, and the loss can be further reduced. Therefore, as in the present embodiment, the forward converter 4, the step-up / step-down power supply circuit 5, and the power storage element 6A (electrolytic capacitor) can be built in the motor power converter 2A.

Further, the blocks up to the output of the appropriate voltage Vref of the storage element 6A (electrolytic capacitor) of the storage energy calculation circuit 14 and the voltage command calculation circuit 15 in the control circuit 8 and the PI adjuster 17 shown in FIG. Since the processing is performed by the CPU 72 of the speed current control circuit 16A, there is no need to add a new CPU.

A third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, only the differences from the first embodiment will be described. In the drawings used in the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment uses a press machine 12A with a servo die cushion having a slide 25 and a servo die cushion device 32 as a motor load, and using a separate power supply for the power supply system of the slide 25 and the servo die cushion device 32. is there.

FIG. 20 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In FIG. 20, the pneumatic die cushion device 31 is replaced with a servo die cushion device 32 with respect to the first embodiment (FIG. 7), and a reaction force is applied from below by a die cushion motor 103, and the die is driven. The cushion motor 103 is controlled by a die cushion motor power converter 121 (AC input).

交流 The motor 103 for the die cushion has an encoder 110 built in an AC motor 109. In addition, the motor power conversion circuit 107 of the die cushion motor power conversion device 121 (AC input) incorporates functions (not shown) such as a forward converter and an inverse converter. And a constant DC voltage is applied to the input of the inverter. That is, motor power conversion circuit 107 is a standard motor power conversion device without a step-up / step-down power supply circuit.

In FIG. 20, wiring for supplying power from the AC power supply 11 is indicated by a single line, and three diagonal lines indicate three-phase wiring. The control circuit 108 of the die cushion motor power converter 121 has the same configuration as the position / velocity / current control circuit 16 (see FIG. 10) shown in the first embodiment. Does not have the function as A motor drive command is given from the host device 13 to the control circuit 108 of the die cushion motor power conversion device 121 (AC input), and the operation mode of the die cushion motor 103 is set during the drawing process. Since the blank is sandwiched between the mold and the lower mold, a reaction force is given by torque control. This torque control gives the same torque as the reaction force when the pneumatic die cushion device 31 is used. It is operated by position control or speed control except during the drawing process.

FIG. 21 is a diagram schematically illustrating the structure of the press with a servo die cushion according to the present embodiment.

In FIG. 21, the press machine 12A with a servo die cushion is different from the press machine 12 with a pneumatic die cushion shown in the first embodiment (see FIG. 3) in that the pneumatic die cushion device 31 is a servo die cushion device. 32, and has a die cushion motor 103 for driving the servo die cushion device 32.

Other configurations are the same as those of the first embodiment.

A fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, only the differences from the third embodiment will be described. In the drawings used in the present embodiment, the same members as those in the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the power of the servo die cushion device 32 in the press machine 12A with the servo die cushion of the third embodiment is supplied from the input of the step-up / step-down power supply circuit 5 (in other words, the output of the forward converter 4). It was done.

FIG. 22 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In FIG. 22, the input power of the die cushion motor power converter 121A (DC input) is connected between the input sides P0-N of the step-up / step-down power supply circuit 5 of the power supply 1. In other words, the die cushion motor power converter 121A (DC input) is a DC power input because it is connected to the output of the forward converter 4, and the motor power conversion circuit 107A does not need the function as a forward converter. is there.

Other configurations are the same as in the third embodiment.

The motor 3 (hereinafter, also referred to as a slide motor 3) and the die cushion motor 103 generate torque in the direction of pressing each other during drawing and cutting. Therefore, when the slide motor 3 operates in the power running direction, the motor 103 for the die cushion is used. Means regenerative operation. Conversely, when the slide motor 3 operates in the regenerative direction, the motor 103 for the die cushion is in power running operation. For example, when the slide motor 3 operates in power running, it is necessary to supply power from the power supply 11 side. At this time, the die cushion motor 103 is in a regenerative state and the power supplied from the power supply is in a surplus state. Become. Since the motor power converter for die cushion 121A (DC input) does not have a function as a step-up / step-down power supply circuit, the voltage level is the same as that of the slide motor 3; And can be connected. In this state, the regenerative power of the die cushion motor 103 can be boosted and supplied as powering power of the slide motor 3 by the step-up / step-down power supply circuit 5, for example, so that power supply from the power supply 11 is suppressed or eliminated. Energy saving can be achieved.

In the opposite case, if the slide motor 3 is regenerating, the voltage of the storage device 6 predicts a regenerative state and the voltage is already in a reduced state, so the regenerative operation starts from that voltage. At this time, since the motor 103 for die cushion is power running, power can be supplied from the power supply 11 side, and power is not supplied from both.

As described above, since the powering and the regeneration are switched in a well-balanced state during the drawing and cutting, the DC voltage P0-N of the power supply device 1 is kept substantially constant regardless of which voltage is in the regeneration state. Therefore, there is an effect that there is no problem even if the elastic load accumulated energy calculation circuit 46 is operated in an invalid state, that is, the clear signal CLR2 is turned on. Since energy is accumulated in the inertia load of the slide motor 3 at the end of the drawing cutting, the inertia load accumulated energy calculation circuit 44 needs to be operated with the validity (clear signal CLR1 is OFF).

A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, only the differences from the first embodiment will be described. In the drawings used in the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is an example of a case where the lifting device is driven by a motor using a load.

FIG. 23 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In this embodiment,
23, the lifting device 82 of the present embodiment includes a hoist 76 (see FIG. 5). The elevating device 82 is a load that can most easily explain the regenerative state as a gravitational load. As the lifting load of the present embodiment, a lifting device having a large difference in height in the direction of gravity is not assumed, and a lifting device for a car or luggage on the floor, a lifting device for storage components between upper and lower shelves, and a component for vertically transporting the inside of the device. Transport is assumed. When the load 77 rises, the motor 3 operates in a power running state due to the operation in the direction opposite to the gravity, and when the load 77 descends, it descends while suppressing the fall, so that the motor 3 enters a regenerative state.

Further, in FIG. 23, in the stored energy calculation circuit 14B (calculation circuit), compared with the stored energy calculation circuit 14 of the first embodiment (see FIG. 7), the elastic load stored energy calculation block 41 has the gravity load stored energy. The calculation block 79 has been replaced. The gravity load accumulated energy calculation block 79 includes a gravity load power calculation circuit 80 and a gravity load accumulated energy calculation circuit 81. However, the gravitational load torque Tw is Tq−Tα as in the above (Equation 12), the gravitational load power calculation circuit 80 calculates the gravitational load power Pw, and the gravitational load storage energy calculation circuit 81 calculates the gravitational load storage energy Ew. Is calculated.

出力 The output Eα of the inertial load accumulated energy calculation block 40 and the output Ew of the gravity load accumulated energy calculation block 79 are added by the addition calculator 50, and the total load accumulated energy E is output to the voltage command calculation circuit 15 of the power supply device 1.

Other configurations are the same as those of the first embodiment.

Also in the present embodiment configured as described above, the voltage command Vref of the storage device 6 shown in the above (Equation 17) is obtained as in the first embodiment.

A sixth embodiment of the present invention will be described with reference to FIG. In the present embodiment, only differences from the first embodiment will be described. In the drawings used in the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the motor is constituted by a linear motor and an encoder.

FIG. 24 is a diagram schematically illustrating an example of the power conversion system according to the present embodiment.

In FIG. 24, the motor 3C includes a linear motor 9C and a position detector (linear encoder, Hall sensor) 10C for acquiring the position of the linear motor 9C.

物理 The physical quantity related to the linear motor 9C of the present embodiment and the physical quantity related to the AC motor 9 shown in the first embodiment correspond as follows. That is, the speed v (m / s), thrust Fq (N), mass M (kg), and (1/2) Mv ＾ 2 of the linear motor 9C are the same as those of the AC motor 9 (that is, the rotary servomotor). It corresponds to angular velocity ω (rad / s), torque Tq (N · m), moment of inertia J (kg · mｋｇ2), and inertia load energy (１／) Jω ＾ 2, respectively.

The inertial load power Pα, the running power Pd, the inertial load energy Eα, and the running energy Ed (corresponding to the above (Equation 3) to (Equation 6) in the case of the AC motor 9) in the linear motor 9C are as follows. (Expression 24) to (Expression 27).

において In the above (Equation 25), the traveling speed v (m / s) = dl / dt and the constant thrust Fq (N).

That is, in FIG. 24, in the stored energy calculation circuit 14C (calculation circuit), the acceleration / deceleration torque calculation circuit 42 related to the moment of inertia J is different from the stored energy calculation circuit 14 of the first embodiment (see FIG. 7). The acceleration / deceleration torque calculation circuit 142 relating to the mass M is replaced. The position / speed current control circuit 16C outputs the mass M to the acceleration / deceleration torque calculation circuit 142 and outputs the thrust Fq instead of the motor load torque Tq. It is configured as follows.

Other configurations are the same as those of the first embodiment.

As described above, even when a linear motor is used, control can be performed in the same manner as in the first embodiment.

<Appendix>
Note that the present invention is not limited to the above-described embodiment, and includes various modifications and combinations without departing from the gist of the present invention. In addition, the present invention is not limited to the configuration including all the configurations described in the above embodiment, and includes a configuration in which a part of the configuration is deleted. Further, the above-described respective configurations, functions, and the like may be realized by designing a part or all of them, for example, with an integrated circuit. In addition, the above-described configurations, functions, and the like may be realized by software by a processor interpreting and executing a program that realizes each function.

DESCRIPTION OF SYMBOLS 1 ... Power supply device, 2, 2A ... Motor power conversion device (power conversion device), 3 ... Motor, 3C ... Linear motor, 4 ... Forward converter, 5 ... Step-up / step-down power supply circuit (step-up power supply circuit, step-down power supply circuit), Reference Signs List 6: power storage device, 6A: storage element, 7: inverter (power conversion unit), 8, 108: control circuit (control unit), 9: AC motor, 9C: AC motor (linear motor), 10: encoder, 10C: Position detector (linear encoder, Hall sensor), 11: AC power supply, 12: Press machine with pneumatic die cushion, 12A: Press machine with servo die cushion, 13: Host device, 14, 14A, 14B, 14C ... Accumulated energy calculation circuit (calculation circuit), 15: voltage command calculation circuit, 16, 16A: position / velocity current control circuit, 17: regulator, 18: insulation amplifier, 20: slide motor, 21: slur Drive means, 22 ... crankshaft, 23 ... crank eccentric part, 24 ... connection rod, 25 ... slide, 26 ... slide gib, 27 ... bolster, 28 ... bed, 29 ... upper mold, 30 ... lower mold, 31 ... pneumatic die cushion device, 32 ... servo die cushion device, 34 ... injection shaft, 35 ... injection molding machine, 40 ... inertia load storage energy calculation block, 41 ... elastic load storage energy calculation block, 42, 142 ... acceleration / deceleration torque Calculation circuit, 43: acceleration / deceleration power calculation circuit, 44: inertial load storage energy calculation circuit, 45: elastic load power calculation circuit, 46: elastic load storage energy calculation circuit, 47: full charge energy setting block, 48: proportional coefficient Block, 49: square root operation circuit, 50: addition operation unit, 51: addition / subtraction operation unit, 52: smoothing capacitor, 53: switch 54, diode, 55, full-wave rectifier, 56, resistor, 58, step-up reactor, 58A, step-down reactor, 59, U-phase current detector (current detector), 60, W-phase current detector (current Detector), 61: drive circuit, 62: position / speed magnetic pole position calculation circuit, 63: speed control circuit (ASR), 64: axis current control circuit (ACR), 65: axis current control circuit (ACR), 66: phase Conversion circuit, 67: circuit, 68: conversion circuit, 73, 74: mode changeover switch, 75: parameter area, 76: hoisting machine, 77: luggage (or basket for storing luggage, etc.), 78: rope, 79 ... Gravity load storage energy calculation block, 80: gravity load power calculation circuit, 81: gravity load storage energy calculation circuit, 82: lifting device, 103: die cushion motor, 107, 107A ... Over data power conversion circuit, 109 ... AC motor, 110 ... encoder, 120 ... motor load, 121, 121a ... die cushion motor power converter

Claims

A power converter for supplying power to the motor,
In a power conversion system including a power supply device that supplies power to the power conversion device,
The power converter,
A power conversion unit that converts power, a control unit that controls the power conversion unit, and a current detection unit that detects a current in the power conversion unit,
The power supply,
A storage device for storing power according to a voltage, a step-up / step-down power supply circuit for changing a voltage of the storage device based on a voltage command, and an energy storage device for calculating energy to be stored in the storage device as the voltage command And an arithmetic circuit for outputting to the circuit,
The control unit calculates power running energy or regenerative energy of the motor using information from an encoder included in the motor and a current value detected by the current detection unit,
The power conversion system, wherein the arithmetic circuit is configured to calculate energy stored in the storage device based on power running energy or regenerative energy of the motor calculated by the control unit.
The power conversion system according to claim 1,
The control unit calculates the angular velocity and torque of the motor using information from the encoder and the current value detected by the current detection unit, and uses the angular velocity and torque and a preset inertia moment value. A power conversion system for calculating power running energy or regenerative energy of the motor.
The power conversion system according to claim 1,
The power conversion system, wherein the arithmetic circuit is configured to calculate the energy stored in the storage device such that the amount of power stored in the storage device becomes the maximum amount of power by the regenerative energy.
The power conversion system according to claim 1,
The power conversion system, wherein the control unit is configured to calculate the regenerative energy based on inertial energy stored in the motor and elastic energy stored in a motor load driven by the motor.
The power conversion system according to claim 1,
The power conversion system, wherein the control unit is configured to calculate the regenerative energy based on inertial energy stored in a motor load driven by the motor and gravitational energy stored in the motor load.
The power conversion system according to claim 2,
The power conversion system, wherein the moment of inertia value is stored during a test run of the motor or during real-time automatic tuning.
Converting power supplied through a storage device that stores power and supplying the converted power to a motor;
A procedure for calculating powering energy or regenerative energy of the motor using information from an encoder included in the motor and a current value supplied to the motor;
Calculating energy to be stored in the storage device based on the calculated powering energy or regenerative energy of the motor;
Changing the power stored in the storage device based on the calculation result of the energy stored in the storage device.
The motor control method according to claim 7,
Calculate the angular velocity and torque of the motor using information from the encoder and the current value supplied to the motor, and use the calculated angular velocity and torque and a preset moment of inertia value to power the motor. A motor control method comprising calculating energy or regenerative energy.
The motor control method according to claim 7,
A motor control method, comprising calculating the energy stored in the storage device such that the amount of power stored in the storage device becomes the maximum amount of power by the regenerative energy.
The motor control method according to claim 7,
A motor control method, comprising: calculating the regenerative energy based on inertial energy stored in the motor and elastic energy stored in a motor load driven by the motor.
The motor control method according to claim 7,
A motor control method, wherein the regenerative energy is calculated based on inertial energy stored in a motor load driven by the motor and gravitational energy stored in the motor load.
The motor control method according to claim 8,
The motor control method according to claim 1, wherein the moment of inertia value is stored during a test run of the motor or during real-time auto-tuning.