JP5452528B2 - Numerical controller - Google Patents

Description

  The present invention relates to a numerical control device.

  In a machine tool that drives a motor to process an object, information on power consumption or regenerative power is required for various purposes such as power consumption improvement.

  Patent Document 1 describes that in a motor drive device of an industrial machine, an input voltage and an input current of a converter unit are measured and the power consumption of the entire motor drive device is obtained using these values. Thereby, according to patent document 1, it is supposed that the power consumption of the whole motor drive device (the whole which combined the converter part, the some inverter part, and the some motor) can be calculated correctly.

  In Patent Document 2, in a motor drive device of an industrial machine, a motor output is calculated from a motor speed detection value, a motor current detection value, and a preset motor torque constant, and a motor loss is calculated from the square of the motor current detection value and the winding resistance. Calculate the amplifier loss from the motor current detection value and the preset amplifier power loss coefficient, calculate the motor output and motor loss, amplifier loss, preset amplifier fixed power consumption, fixed power consumption of peripheral devices Is calculated to calculate the power consumption of the entire industrial machine. Thereby, according to patent document 2, it is supposed that the power consumption of the whole industrial machine can be calculated, without using special apparatuses, such as a wattmeter.

JP 2010-74818 A JP 2010-115063 A

  Patent Document 1 merely describes obtaining power consumption of the entire motor drive device from each measured value of the input voltage and input current of the converter unit, and for each axis on which the inverter unit and the motor are provided. It is not assumed that power consumption will be obtained.

  Patent Document 2 describes that the power consumption of the entire industrial machine and each axis is obtained by calculation, but it is difficult to calculate them accurately.

  That is, in order to accurately calculate the power consumption for each axis, it is necessary to accurately calculate the motor loss and the amplifier loss. However, preset constants such as motor winding resistance required to accurately calculate motor loss and amplifier loss vary depending on various conditions such as motor temperature. Have difficulty. In the technique described in Patent Document 2, motor loss is calculated from the square of the motor current detection value and the winding resistance, and amplifier loss is calculated from the motor current detection value and a preset amplifier power loss coefficient. If the power consumption for each axis is calculated by adding inaccurate motor loss or amplifier loss to the motor output in this way, the value also becomes inaccurate.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a numerical control device capable of accurately calculating the power for each axis.

  In order to solve the above-described problems and achieve the object, a numerical control device according to one aspect of the present invention includes a converter unit that converts AC power into DC power, and the DC power converted by the converter unit as AC power. A numerical control device for calculating power of a machine tool drive unit having a plurality of amplifiers for conversion into motors and a plurality of motors respectively driven by AC power converted by the amplifiers, wherein the amplifiers and the motors are provided for respective axes The converter power acquisition means for acquiring the output power of the converter section as converter output power, the motor output calculation means for calculating the output of the motor for each axis as the motor output, the converter output power and the motor output Total loss calculation means for calculating the difference between the total sum of all axes as total loss, and the motor loss as motor loss for each axis Motor loss calculating means for calculating, amplifier loss calculating means for calculating the loss of the amplifier as an amplifier loss for each axis, and axis loss calculating means for calculating the sum of the motor loss and the amplifier loss as an axis loss for each axis And, based on the ratio of the shaft loss for each shaft to the total sum of the shaft losses for all shafts, a loss distribution means for obtaining, for each shaft, a loss obtained by distributing the total loss for each shaft as a distribution shaft loss, and the motor output And an axis power calculation means for obtaining for each axis the axis power as the sum of the distribution axis loss and the distribution axis loss.

  According to the present invention, it is possible to calculate the shaft loss for each axis taking into account errors generated when calculating the motor loss for each axis and the amplifier loss for each amplifier, and losses that have not been considered. The power consumption for each axis can be accurately calculated.

FIG. 1 is a diagram illustrating a configuration of a numerical control device according to an embodiment. FIG. 2 is a diagram illustrating a configuration of a numerical controller according to a modification of the embodiment. FIG. 3 is a diagram illustrating a configuration of a numerical control device according to a modification of the embodiment.

  Embodiments of a numerical controller according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
A numerical controller 2 according to an embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating the configuration of the numerical control device 2 and also the configuration of the machine tool drive unit 1 that is a control target of the numerical control device 2. Note that the solid line in FIG. 1 represents the power supply path, and the broken line arrow represents the signal transmission path.

  The numerical control device 2 controls the machine tool drive unit 1. Further, the numerical controller 2 calculates the power of the machine tool drive unit 1.

  The machine tool drive unit 1 has one converter unit 110 and amplifiers 12-1 to 12 -N and motors 13-1 to 13 -N for each shaft as N shafts connected to the converter unit 110. Note that the number after the hyphen “-” in the member number corresponds to the axis number.

  The converter unit 110 includes a power conversion circuit 111 and a converter power measurement unit 112. The three-phase AC power supplied from the factory power supply 100 is converted into converter output power, which is DC power, by the power conversion circuit 111 of the converter unit 110, and supplied to the amplifiers 12-1 to 12-N of each axis.

  Converter power measurement means 112 of converter unit 110 measures the converter output power converted by power conversion circuit 111. The amplifiers 12-1 to 12 -N of each axis convert the DC power supplied from the converter unit 110 into desired three-phase AC power and supply it to the corresponding motors 13-1 to 13 -N. The motors 13-1 to 13-N of each axis are driven by three-phase AC power supplied from the corresponding amplifiers 12-1 to 12-N.

  In the present embodiment, the machine tool drive unit 1 has one converter unit 110 and amplifiers 12-1 to 12 -N and motors 13-1 to 13 -N connected to each axis. The machine tool drive unit 1 may have a plurality of configurations. For example, the machine tool drive unit 1 may be configured such that a plurality of converters and amplifiers 12-1 to 12-N and motors 13-1 to 13-N are connected to each converter for each axis.

  In this embodiment, converter power measuring means 112 is included in converter unit 110. However, using an independent wattmeter or voltmeter / ammeter, converter output power or converter output voltage / converter output current is calculated. You may measure. When the converter output voltage / converter output current is measured by the voltmeter / ammeter, the converter power acquisition means 300 described later acquires the converter output voltage output from the voltmeter and the converter output current output from the ammeter. The converter output power may be obtained by multiplying the converter output voltage and the converter output current to obtain the converter output power.

  The numerical controller 2 includes a rotational speed measuring unit 200, a motor current measuring unit 210, a converter power obtaining unit 300, a motor output calculating unit 310, a motor loss calculating unit 320, an amplifier loss calculating unit 330, a total loss calculating unit 340, a shaft loss. The calculation unit 350, the loss distribution unit 360, and the shaft power calculation unit 370 are included.

  The rotational speed measuring means 200 measures the rotational speed of the motor as the motor rotational speed, and the motor current measuring means 210 measures the current flowing through the motor as the motor current.

  Next, converter power acquisition means 300 acquires converter output power Wc output from converter power measurement means 112. When converter power measuring means 112 outputs converter output voltage / converter output current, converter power acquisition means 300 acquires converter output voltage / converter output current, and calculates the product of converter output voltage and converter output current as the converter. Converter output power Wc is acquired by calculating as output power Wc.

Next, the motor output calculation means 310 uses the motor rotation speed for each motor measured by the rotation speed measurement means 200 and the motor current for each motor measured by the motor current measurement means 210, for each motor. Calculate the output. Specifically, as shown in Equation 1 below, the product of the motor rotation speed ω _n of the motor n, the motor current Im _n of the motor _n , and the motor torque constant T _n of the motor n set in advance is the motor output Wm. Calculate as _n .

Wm _n = ω _n × (Im _n × T _n ) (Formula 1)

Next, the motor loss calculating unit 320 calculates the motor loss for each motor using the motor current for each motor measured by the motor current measuring unit 210. Specifically, as shown in Equation 2 below, motor fixed power consumption Lfm _n of motor n and motor winding resistance Rmn of motor _n are set in advance, and the square of motor current Im _n of motor n is set. and it calculates the product of the motor winding resistance Rm _n, the sum of the motor fixing power Lfm _n of the motor n as motor loss Lm _n of the motor n. In this embodiment, the motor loss is the sum of the product of the square of the motor current and the motor winding resistance and the fixed motor power consumption. However, when the fixed motor power consumption is small, the square of the motor current and the motor winding Only the product of the line resistance may be the motor loss.

Lm _n = (Im _n ² × Rm _n ) + Lfm _n (Expression 2)

Next, the amplifier loss calculating unit 330 calculates the amplifier loss for each amplifier using the motor current for each motor measured by the motor current measuring unit 210. Specifically, as shown in Equation 3 below, the amplifier fixed power Lfa _n and the amplifier n, amplifier loss coefficient Ka n of amplifier _n, previously set an amplifier electrical resistance Ra _n of amplifier n, a motor and the product of the amplifier resistance Ra _n squared and amplifier n of n of the motor current Im _n, the absolute value of the product of the amplifier loss coefficient Ka _n of the motor current Im _n and the amplifier n of the motor n, amplifiers of the amplifier n the sum of the fixed power consumption Lfa _n is calculated as an amplifier loss La _n of amplifier n. Incidentally, taking the absolute value of the product of the motor current Im _n and amplifier loss coefficient Ka _n is loss during regeneration even during power running is for all positive values. In the present embodiment, the sum of the product of the square of the motor current and the amplifier electrical resistance, the absolute value of the product of the motor current and the amplifier loss factor, and the amplifier fixed power consumption is defined as the amplifier loss. When the product of the square of the current and the amplifier electrical resistance is small, the product of the square of the motor current and the amplifier electrical resistance may be ignored. When the absolute value of the product of the motor current and the amplifier loss coefficient is small, the absolute value of the product of the motor current and the amplifier loss coefficient may be ignored. Further, when the fixed power consumption of the amplifier is small, the fixed power consumption of the amplifier may be ignored.

^{_{La n = (Im n 2 ×}} Ra n) + | Im n × Ka n | + Lfa n ··· ( Equation 3)

Next, the total loss calculation means 340 uses the converter output power output from the converter power acquisition means 300 and the motor output for each motor output from the motor output calculation means 310, so that the entire machine tool drive unit 1 Calculate the loss. Specifically, as shown in Equation 4 below, it calculates the difference between the total motor summation of the motor output Wm _n of the converter output power Wc and the motor n as total loss L. Here, N is the number of axes supplied with power by the converter unit 110.

_N
L = Wc−ΣWm _n (Expression 4)
^{n = 1}

Next, the shaft loss calculating means 350 uses the motor loss for each motor output from the motor loss calculating means 320 and the amplifier loss for each amplifier output from the amplifier loss calculating means 330 to calculate the loss for each axis. calculate. More specifically, as shown in Equation 5 below, it calculates the sum of the amplifier loss La _n of motor loss Lm _n and amplifier n of the motor n as axial loss L _n axis n.

L _n = Lm _n + La _n (Formula 5)

Next, the loss distributing unit 360 distributes the total loss output from the total loss calculating unit 340 for each axis by using the axial loss for each axis output from the axial loss calculating unit 350. Specifically, as shown in Equation 6 below, the product of the ratio of the axial loss L _n of the axis n to the total axial sum of the axial losses and the total loss L is calculated as the distribution axial loss L _n ′ of the axis n. To do.

L _n
L _n '= ───── × L ... (Formula 6)
_N
ΣL _n
^{n = 1}

Next, the shaft power calculation means 370 uses the motor output for each motor output from the motor output calculation means 310 and the distribution axis loss for each axis output from the loss distribution means 360 to generate the shaft power for each axis. Ask for. Specifically, as shown in Equation 7 below, it calculates the sum of the distribution shaft loss L _n 'of the motor output Wm _n and the axis n of the motor n as a shaft power W _n axis n.

W _n = Wm _n + L _n '(Expression 7)

  As described above, in the present embodiment, the total loss is obtained by the difference between the sum of the converter output power and the motor output, and the total loss is distributed for each axis by the ratio of the loss for each axis calculated by the calculation formula. The loss is obtained, and the sum of the distribution shaft loss and the motor output is obtained to obtain the shaft power for each shaft. This makes it possible to calculate the shaft loss for each axis, taking into account errors that occur when calculating motor loss for each axis and amplifier loss for each amplifier, and losses that cannot be considered. Compared to the case where the shaft power calculated for each axis is added to the motor output to determine the shaft power for each axis, the axis power for each axis can be calculated more accurately. It is possible to present more accurate power information for improving the power. That is, the power for each axis can be accurately calculated.

  The numerical controller 2i may further include an output integration unit 400i as shown in FIG. The output integration unit 400i integrates the converter output power output from the converter power acquisition unit 300 and the motor output for each motor output from the motor output calculation unit 310 over a preset power integration period. The converter output power amount and the motor output amount for each motor during the power integration period can be calculated.

  Further, the numerical controller 2i may further include a loss integrating means 410i as shown in FIG. The loss integrating unit 410i integrates the total loss output from the total loss calculating unit 340 and the distribution axis loss for each axis output from the loss distributing unit 360 over a preset loss integrating period, It is possible to calculate the total loss amount and the distribution axis loss amount for each axis during the loss integration period. It is desirable that the power integration period and the loss integration period are the same.

  Moreover, the numerical controller 2i may further include a power amount display unit 500i as shown in FIG. The power amount display means 500i is a means for displaying the power amount and the loss amount, which is a time integration value of power and loss. The converter output power amount output from the output integration means 400i, the motor output amount for each motor, and the loss The total loss amount output from the integrating means 410i and the distribution axis loss amount for each axis can be displayed. As for the items to be displayed, all of the converter output power amount, the motor output amount, the total loss amount, and the distribution axis loss amount may be displayed, or preset items may be selectively displayed. As for the motor output amount, the motor output amount of all the motors may be displayed, the motor output amount of a preset motor may be selectively displayed, or the motor output amount is in descending order. You may display only the number of display axes set beforehand. Similarly, with regard to the distribution axis loss amount, the distribution axis loss amount of all axes may be displayed, the distribution axis loss amount of a preset axis may be selectively displayed, or the distribution axis loss amount may be displayed. You may display only the number of display axes set beforehand in order of the axis with the largest quantity.

  Further, the power amount display means 500i is configured such that the ratio of the total loss amount to the converter output power amount exceeds a preset allowable loss amount ratio, or the distribution shaft loss amount to the motor output amount for each axis is preset. When the allowable axis loss amount ratio is exceeded, an alarm (warning) may be displayed. In these cases, the method of notifying the warning may be a method of notifying the alarm by the speaker (not shown) in addition to the alarm display by the power amount display means 500i, or a warning light. You may alert | report by blinking a lamp | ramp by (not shown).

  As described above, the numerical control device 2i shown in FIG. 2 can also calculate and display the cumulative value obtained by integrating the converter output power, the motor output, the total loss, and the distribution axis loss over a predetermined period. It is possible to present necessary information for improving the power consumption. More preferably, since it is also possible to automatically display an axis with a large amount of power or loss, it is possible to automatically present more important power information without requiring troublesome settings for display. .

  Further, in the numerical control device 2i shown in FIG. 2, when the ratio of the total loss amount to the converter output power amount, that is, the total power consumption exceeds a predetermined value, or the distribution shaft loss to the motor output amount, that is, the shaft power consumption amount. By displaying an alarm when the ratio of the amount exceeds a predetermined value, an abnormality related to the power transmission of the motor or amplifier, such as motor insulation deterioration, can be notified. Therefore, it is possible to prompt the user to repair or replace the motor or amplifier before the motor or amplifier fails, it is possible to improve productivity, and the machine tool is always in a power efficient condition. Therefore, energy-saving processing can be realized.

  Alternatively, the numerical controller 2j can include power display means 510j as shown in FIG. The power display means 510j is a means for displaying the instantaneous value or time waveform of power and loss, the converter output power output from the converter power acquisition means 300, the motor output for each motor output from the motor output calculation means 310, all The total loss output from the loss calculation means 340 and the distribution axis loss for each axis output from the loss distribution means 360 can be displayed. Regarding the items to be displayed, all of converter output power, motor output, total loss, and distribution axis loss may be displayed, or preset items may be selectively displayed. As for the motor output, the motor outputs of all motors may be displayed, the motor outputs of preset motors may be selectively displayed, or the motor outputs are pre-ordered in descending order of the motor output amount. You may display only the number of display axes that have been set. Similarly, with respect to the distribution axis loss, distribution axis loss of all axes may be displayed, distribution axis loss of a preset axis may be selectively displayed, and the distribution axis loss amount is large. The distribution axis loss may be displayed by the number of display axes set in advance in the axis order.

  Further, the power display means 510j is configured so that the ratio of the total loss to the converter output power exceeds a preset maximum loss ratio, or the distribution axis loss for the motor output for each axis exceeds the preset maximum axis loss ratio. In the case of an alarm, an alarm (warning) may be displayed. The method for notifying the warning in these cases may be a method for notifying the alarm by sound such as an alarm sound through a speaker (not shown) in addition to displaying the alarm by the power display means 510j. You may alert | report by blinking a lamp | ramp etc. by not shown).

  As described above, the numerical control device 2j shown in FIG. 3 can calculate the instantaneous values of the converter output power, the motor output, the total loss, and the distribution axis loss, and display the instantaneous value or the time waveform. It is possible to present necessary information for improving the power consumption of the machine. More preferably, since it is possible to automatically display an axis with a large power or loss, it is possible to automatically present more important power information without requiring a troublesome setting for display.

  Also, an alarm is displayed when the ratio of converter output power, that is, the total loss to total power consumption, exceeds a predetermined value, or when the ratio of motor output, that is, the distribution axis loss, to shaft power consumption exceeds a predetermined value. Thus, it is possible to notify an abnormality related to the power transmission of the motor and the amplifier such as motor insulation deterioration. Therefore, it is possible to repair or replace the motor or amplifier before the motor or amplifier breaks down, and it is possible to improve the productivity, and it is always possible to use the machine tool under the condition of power efficiency. Therefore, it is possible to realize energy saving machining.

  In the above embodiment, power consumption and regenerative power such as converter output power, motor output power, and shaft power are described as power without particular distinction, but power during power running is positive and power during power regeneration. By assuming that the power is negative and the loss is always positive regardless of power running or regeneration, it is possible to calculate power consumption and regenerative power without particularly distinguishing between power running and regeneration.

  In the modification of the above-described embodiment, only the screen display has been described in the description of the power amount display means 500i and the power display means 510j. However, it may be output to an external device by data communication.

  As described above, the numerical control device according to the present invention is useful for calculating electric power.

DESCRIPTION OF SYMBOLS 1 Machine tool drive part 2, 2i, 2j Numerical control apparatus 100 Factory power supply 110 Converter part 12-1 to 12-N Amplifier 13-1 to 13-N Motor 300 Converter electric power acquisition means 310 Motor output calculation means 320 Motor loss calculation means 330 Amplifier loss calculation means 340 Total loss calculation means 350 Axis loss calculation means 360 Loss distribution means 370 Axis power calculation means 400i Output integration means 410i Loss integration means 500i Power amount display means 510j Power display means

Claims (6)

A converter unit that converts AC power into DC power, a plurality of amplifiers that convert the DC power converted by the converter unit into AC power, and a plurality of motors that are respectively driven by the AC power converted by the amplifier. A numerical control device for calculating the power of a machine tool drive unit in which an amplifier and the motor are provided for each axis,
Converter power acquisition means for acquiring output power of the converter unit as converter output power;
Motor output calculating means for calculating the output of the motor for each axis as a motor output;
A total loss calculating means for calculating the difference between the converter output power and the sum of all the motor output axes as a total loss;
Motor loss calculating means for calculating the motor loss as a motor loss for each axis;
An amplifier loss calculating means for calculating the loss of the amplifier for each axis as an amplifier loss;
A shaft loss calculating means for calculating the sum of the motor loss and the amplifier loss as a shaft loss for each shaft;
Based on the ratio of the axial loss for each axis to the total sum of the axial losses for all axes, a loss distribution means for determining, for each axis, a loss obtained by distributing the total loss for each axis as a distribution axial loss;
A shaft power calculation means for determining, for each shaft, the sum of the motor output and the distribution shaft loss as a shaft power,
A numerical control device comprising: Output integration means for calculating the integrated value in a predetermined period of the converter output power and the motor output as a converter output power amount and a motor output amount, respectively;
Loss integration means for calculating the total value of the total loss and the distribution axis loss for a predetermined period as a total loss amount and a distribution axis loss amount, respectively;
The numerical control apparatus according to claim 1, further comprising: The power display means for displaying at least one instantaneous value or time waveform among the converter output power, the motor output, the total loss, and the distribution axis loss is further provided. Numerical control unit. 3. The numerical value according to claim 2, further comprising: a power amount display unit that displays at least one of the converter output power amount, the motor output amount, the total loss amount, and the distribution axis loss amount. Control device. Warning if the ratio of the total loss to the converter output power is greater than a preset allowable loss ratio, or the ratio of the distribution shaft loss to the motor output is greater than a preset allowable axis loss ratio The numerical control device according to claim 1, further comprising a notification unit that notifies   When the ratio of the total loss amount to the converter output power amount is larger than a preset allowable loss amount ratio, or the ratio of the distribution shaft loss amount to the motor output amount is a preset allowable shaft loss amount ratio The numerical control device according to claim 2, further comprising notification means for notifying a warning when the value is larger than the value.

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