JP3504160B2 - Servo control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo control device for controlling a servo motor such as a synchronous motor, and more particularly to a servo control device for performing stop control in a servo lock state.

[0002]

2. Description of the Related Art FIG. 9 shows a servo system using a conventional servo control device. In FIG. 9, reference numeral 1 denotes a servo motor such as a synchronous motor (SM servo motor).
Reference numeral 0 denotes a servo control device including a power conversion unit 11, a control circuit unit 12, and a display unit 13, respectively. The servo motor 1 is controlled by the servo control device 10. The servomotor 1 is connected to a detector 2 that detects the rotational position, rotational direction, and magnetic pole position of the servomotor 1. Further, the servo motor 1 is provided with a motor cooling fan 3 that cools the servo motor 1.

The power conversion section 11 is a converter (rectification) section 14 for converting the alternating current supplied from the alternating current power source 5 into direct current.
A smoothing capacitor 15 connected to the DC side of the converter unit 14, an inverter unit 16 connected to the subsequent stage of the smoothing capacitor 15 to convert DC into three-phase AC, and an inverter cooling fan 17 for cooling the inverter unit 16. It is composed of and.

The control circuit section 12 outputs a position control circuit 21 for generating a speed command according to a deviation between a position command given by the controller 30 and a position feedback value detected by the detector 2, and the detector 2. A speed calculation circuit 22 that calculates a motor speed based on a position signal, and a speed control circuit that generates a current command corresponding to a deviation between a speed command output by the position control circuit 21 and a speed feedback value output by the speed calculation circuit 22. 23, and a current control circuit for outputting to the inverter unit 16 an inverter control command according to the deviation between the current command output by the speed control circuit 23 and the current value on the output side of the power conversion unit 11 detected by the current detector 18. 24 and.

According to the above-mentioned structure, a position control loop, a speed control loop, and a current control loop are formed. Under these control loops, the inverter section 16 obtains direct-current commanded motor characteristics. The voltage and the frequency are converted into a three-phase alternating current and supplied to the servomotor 1.

10 and 11 show the waveforms of the three-phase AC currents U, V, W output from the inverter section 16, respectively. FIG. 10 shows the case where the servo motor 1 is rotating at a certain rotation speed, and FIG. 11 shows the case where the servo motor 1 is stopped in the servo lock state.

When the servo motor 1 is rotating at a certain rotation speed, a sine wave current having a frequency corresponding to the rotation speed is supplied to the servo motor 1. At this time, the continuous current applied to the servo motor 1 has an effective value 0.7 times as large as the current peak value shown in FIG. 10, and a current equal to or less than this effective value is normally applied to the winding of the servo motor 1. Even in the case of continuous flow, the temperature rise value of the motor winding is below the specified value. On the other hand, when the servo motor 1 is stopped in the servo locked state, a constant current that does not change with time flows as shown in FIG. In this case, the current due to the current peak value will be continuously applied.

Since the inverter section 16 generates U, V, and W phases of three-phase AC based on the magnetic pole position of the servomotor 1 detected by the detector 2, the U, V, and W phases of the servomotor 1 are rotated by U, The V and W phase currents are determined. Therefore, when the servo motor 1 is stopped at a specific position within one rotation in a servo-locked state, the current in the specific phases of the U, V, and W phases is equal to or more than the effective value, and the maximum current is The current due to the peak value will be continuously applied.

[0009]

Since the conventional servo control device is constructed as described above, when the servo motor 1 is stopped in the servo lock state at a specific position within one rotation of the motor, U, V, At a maximum value or more of the effective value, the current due to the current peak value is continuously applied to the specific phase of the W phase, and the heat generation of the specific phase of the motor winding or the inverter section of the amplifier is large. Therefore, there is a possibility that these temperature increases may exceed a specified value. For this reason, conventionally, it is necessary to suppress the usable torque to 0.7 times or less that during rotation.

However, even if the torque is suppressed to 0.7 times or less of that during rotation, if the motor is continuously used, the cumulative amount of heat generated will shorten the service life of the motor winding and the inverter section, resulting in damage. Will be reached.

Since it takes a long time to replace the parts to restart the operation, a large profit or loss occurs when it is used in a production line of a factory. In addition, in order to prevent the shortening of the life and the prevention of damage, it is necessary to increase the capacity (amplifier capacity) of the motor and the power converter, resulting in a large installation space and an increase in cost.

The present invention has been made in order to solve the above-mentioned problems, and even when the motor requires a high torque during a stop in a servo lock state at a specific position within one rotation of the motor, the motor can be used. It is an object of the present invention to obtain an improved servo control device capable of preventing the windings and the inverter unit from being damaged by heat and dealing with them without increasing the capacity of the motor and the power conversion unit.

[0013]

In order to achieve the above-mentioned object, the servo control device according to the present invention comprises a detection means for detecting that the servo motor is stopped in a servo lock state at a specific position within one rotation. If the number of stops is equal to the specified stop count, a warning is output.

In the servo control device according to the next invention, the heat generation amount of the inverter portion when stopped in the servo lock state is calculated from the current value and the time when the servo lock state is stopped, and the temperature of the inverter portion is calculated from the heat generation amount. The amount of increase is estimated, and the stop frequency prescribed value is set according to the estimated amount of temperature increase.

A servo control device according to the next invention has a detection means for detecting that the servo motor is stopped in a servo lock state at a specific position within one rotation, and if the stop time reaches a stop time specified value. It outputs a warning.

In the servo control device according to the next invention, the heat generation amount of the servo motor during the stop in the servo lock state is calculated from the current value and the time during the stop in the servo lock state, and the temperature of the servo motor is calculated from the heat generation amount. The amount of increase is estimated, and the stop time prescribed value is set according to the estimated amount of temperature increase.

The servo control device according to the next invention has a detecting means for detecting that the servo motor is stopped in a servo lock state at a specific position within one rotation, and the servo motor current value at the time of stop is the current regulation. If the value is reached, a warning will be output.

The servo control device according to the next invention increases the rotation speed of the motor cooling fan at the time of outputting a warning.

In the servo control device according to the next invention, the rotation speed of the inverter cooling fan is increased when a warning is output.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the embodiments of the present invention described below, parts having the same configurations as those of the above-described conventional example are denoted by the same reference numerals as those of the above-described conventional example, and description thereof will be omitted.

Embodiment 1. 1 shows Embodiment 1 of a servo system including a servo control device according to the present invention. Servo control device 1
The control circuit unit 120 of 00 has a position detection circuit 121, a positioning load detection circuit 122, and a positioning detection circuit 121 in addition to a position control circuit 21, a speed calculation circuit 22, a speed control circuit 23, and a current control circuit 24 which are equivalent to those of the conventional one. Time detection circuit 1
It has 23 detection circuits, positioning frequency memory 124, positioning load memory 125, positioning time memory 126, and warning output circuit 127.

The positioning detection circuit 121 receives the position signal from the detector 2 and the speed signal from the speed calculation circuit 22,
It is determined that the stop position when the servo motor 1 stops at a specific position within one rotation of the servo motor 1 in the servo lock state is fixed. The positioning count memory 124 records the stop position and the stop count detected by the positioning detection circuit 121.

FIG. 2 shows the positioning frequency memory 124 when the position within one rotation of the servo motor 1 is divided into 16384.
Shows the contents of. In the data table configuration of the positioning count memory 124, an address is a position within one rotation of the servo motor 1 and data is a stop count. The positioning load detection circuit 122 inputs the stop detection signal due to the servo lock from the positioning detection circuit 121 and the current detection values of the three-phase AC currents U, V, and W from the current detector 18, and within one revolution of the servo motor 1. The current values of the three-phase AC currents U, V, W output from the inverter unit 16 are detected when the servo motor 1 stops in the servo lock state at the specific position. The positioning load memory position 125 is U when the servo lock is stopped, which is detected by the positioning load detection circuit 122.
Record the V and W phase current values.

FIG. 3 shows the positioning load memory 12 when the position within one rotation of the servo motor 1 is divided into 16384.
The contents of 5 are shown. In the data table configuration of the load memory 125 for positioning, the address is set to 1 of the servo motor 1.
The position is within the rotation, and the data is the current value.

The positioning time detection circuit 123 is a kind of timer, and receives the stop detection signal by the servo lock from the positioning detection circuit 121, and the servo motor 1 is in the servo lock state at a specific position within one rotation of the servo motor 1. Detects the time (positioning time) when stopped at. The positioning time memory 126 records the positioning time detected by the positioning time detection circuit 123.

FIG. 4 shows a positioning time memory 126 when the position within one rotation of the servo motor 1 is divided into 16384.
Shows the contents of. In the data table configuration of the positioning time memory 126, an address is a position within one rotation of the servo motor 1 and data is a stop time.

For a servomotor having four or more poles, when the number of poles is 2P, a position where the magnitude and phase of the current are the same with respect to the position within one rotation occurs P times at symmetrical positions. Address in memory is 16384 / P
And

The warning output circuit 127 inputs recorded values from the positioning frequency memory 124, the positioning load memory 125, and the positioning time memory 126, and determines whether the servo lock is stopped once based on the servo motor current value and the stop time. The heat generation amounts of the U, V, and W phases of the inverter unit 16 are calculated, the temperature rise value ΔTi is estimated, and based on the relationship between the temperature rise value ΔTi and the life cycle number as shown in FIG. When the number of life cycles for the temperature rise value ΔTi exceeds the specified number of stops, a warning is output and the display unit 1
Display in 3.

FIG. 5 shows the relationship between the temperature rise value ΔTi of the transistor used in the inverter unit 16 and the life cycle number. The relationship between the temperature rise value and the cycle number until the end of life is generally known. Has been. Based on this relationship, the life of the inverter unit 16 can be estimated.

FIG. 6 shows the temperature rise value and the life time of the insulating material used for the winding portion of the servo motor 1, and the relationship between the temperature rise value and the life time until reaching the life is generally known. Has been. Servo motor 1
Can estimate the lifespan of.

As a result, the warning output circuit 127
The amount of heat generation of the U, V, and W phases of the servo motor 1 during one stop is calculated from the servo motor current value and the stop time, and the temperature increase value ΔTm is estimated from the heat generation amount. Then, when the life time for this temperature rise value ΔTm becomes equal to or longer than the specified stop time value, a warning is output and displayed on the display unit 13.

The warning output circuit 127 has U, V, W
If the detected current value of the phase exceeds the specified value (specified current value) that can be applied to the inverter unit 16 and the servo motor 1 even for a short time, a warning is immediately output and displayed on the display unit 13. This deals with the fact that the current that can be applied to the inverter unit 16 and the servomotor 1 has an upper limit so as not to be damaged even in a short time.

Next, the operation of warning output and display at the time of stopping the servo lock state of the servo control device configured as described above will be described with reference to the flow chart shown in FIG. First, it is determined from the motor rotation speed detected by the servo motor 1 by the speed calculation circuit 22 that the servo motor 1 has stopped in the servo lock state (step S).
1).

When it is determined that the servo motor 1 has stopped in the servo lock state, the positioning time detection circuit 123
The stop time t is detected by (step S2), and the current value I when the servo lock state is stopped is detected by the positioning load detection circuit 122 (step S3). Next, the inverter heat generation amount Qi at the time of stop is calculated from the stop time t and the current value I (step S4), the temperature rise value ΔTi of the inverter unit 16 is calculated from this inverter heat generation amount Qi (step S5), and the positioning count is determined. The stop count N is added and recorded in the memory 124 (step S6).

Next, the stop count N is compared with the specified value (stop count specified value) Nmax of the life cycle number corresponding to the temperature rise value as shown in FIG. 5 (step S7), and the stop count N is determined. When the number of stop times exceeds the specified value Nmax, a warning is output (step S8) and a warning is displayed on the display unit 13 (step S9). The stop count N is the stop count specified value Nma
If it is less than x, the process returns to step S1.

Further, the heat generation amount Qm of the servo motor 1 is calculated from the stop time t and the current value (step S10), and the temperature rise value ΔTm of the servo motor 1 is calculated from this motor heat generation amount Qm.
Is calculated (step S11). Next, the temperature rise value ΔT
The stop time tm for m and the stop time specified value tmax corresponding to the temperature rise value as shown in FIG. 7 are compared (step S12), and the stop time tm is determined as the stop time specified value tma.
If x or more, a warning is output (step S8) and a warning is displayed on the display unit 13 (step S9). When the stop time tm is less than the stop time specified value tmax, step S1
Return to.

Further, the current value I is compared with the specified current value Imax with respect to the upper limit value that can be applied to the inverter section 16 and the servo motor 1 (step S13). If the current value I exceeds the specified current value Imax, a warning is output. (Step S
8), a warning is displayed on the display unit 13 (step S9). If the current value I is less than the specified current value Imax, step S
Return to 1.

By the above-described processing, whether the number of stops N becomes equal to or greater than the specified number of stops Nmax, the stop time tm becomes equal to or greater than the specified stop time tmax, or the current value I becomes the specified current value I.
If the value is equal to or more than max, a warning is output and a warning is displayed. This warning can call the user's attention and prevent the inverter unit 16 and the servomotor 1 from being damaged.

Embodiment 2. FIG. 8 shows a second embodiment of a servo system including a servo control device according to the present invention. In FIG. 8, the same or the same constituents as those shown in FIG. 1 are designated by the same reference numerals as those shown in FIG. 1, and the description thereof will be omitted.

FIG. 8 is a block circuit diagram of a synchronous control motor according to the fourth embodiment of the present invention. In this embodiment, an inverter unit 128 for a cooling fan, which controls the energization currents to the motor cooling fan 3 and the inverter cooling fan 17 and controls the fan rotation speed of these, is provided in association with the power conversion unit 11, and Control circuit 120
Is provided with a fan control circuit 129. The fan control circuit 129 inputs a signal from the warning output circuit 127,
When outputting the warning, the inverter unit 128 is instructed to increase the voltage and frequency generated by the inverter unit 128.
Output to.

As a result, at the time of warning output, the rotation speeds of the motor cooling fan 3 and the inverter cooling fan 17 increase, and the heat generated in the servo motor 1 and the inverter unit 16 is taken away, and the servo motor 1 and the inverter unit 16 are overheated. Deter.

[0042]

As can be understood from the above description, according to the servo control device of the present invention, when the number of stops in the servo lock state reaches the specified number of stops, a warning is output. It can be notified and even if the load is concentrated on a specific phase of the winding part of the servo motor during the stop in the servo lock state, it prevents the motor winding and the inverter part from being damaged by heat. However, it is possible to deal with the problem without increasing the capacities of the motor and the power converter.

According to the servo control device of the next invention, since the specified stop frequency is set according to the estimated temperature rise of the inverter, the specified stop count is changed according to the temperature rise of the inverter. Even when the application is properly set and requires a high torque during a stop in the servo lock state, it is possible to prevent the inverter section from being damaged by heat and deal with it without increasing the capacity of the power conversion section. Become.

The servo control device according to the next invention outputs a warning if the time during which the servo motor is stopped in the servo lock state at a specific position within one rotation reaches the stop time specified value, and informs the user of this. Even when the load is concentrated on a specific phase of the winding part of the servo motor during the stop in the servo lock state, it is possible to prevent the motor winding and the inverter part from being damaged by heat. It is possible to deal with the problem without increasing the capacities of the motor and the power converter.

According to the servo control device of the next invention, the stop time specified value is set according to the estimated temperature increase amount of the servo motor. Therefore, the stop time specified value is appropriate according to the temperature increase amount of the servo motor. It is possible to prevent the motor winding from being damaged by heat even if the application requires high torque while the servo motor is stopped in the servo lock state, and it is possible to deal with it without increasing the capacity of the servo motor. .

The servo control device according to the next invention outputs a warning when the servo motor current value when stopped in the servo lock state reaches the specified current value, so that the user can be informed of this fact. Even if the load concentrates on a specific phase of the winding part of the servo motor during the stop in the locked state, the motor winding and the inverter part are prevented from being damaged by heat, and the motor and power conversion are prevented. It becomes possible to deal with this without increasing the capacity of the department.

According to the servo control device of the next invention, since the rotation speed of the motor cooling fan increases at the time of warning output, the servo motor is strongly cooled and the motor winding is damaged by heat. Can be prevented.

According to the servo control device of the next invention, since the rotation speed of the inverter cooling fan increases at the time of warning output, the inverter part is strongly cooled and the inverter part is prevented from being damaged by heat. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a servo system including a servo control device according to the present invention.

FIG. 2 is an explanatory diagram showing a data table configuration of a positioning frequency memory used in the servo control device according to the present invention.

FIG. 3 is an explanatory diagram showing a data table configuration of a positioning load memory used in the servo control device according to the present invention.

FIG. 4 is an explanatory diagram showing a data table configuration of a positioning time memory used in the servo controller according to the present invention.

FIG. 5 is a relationship diagram between the temperature rise value of the inverter unit and the number of life cycles.

FIG. 6 is a relationship diagram between a temperature rise value and a life time of a motor winding portion.

FIG. 7 is a flowchart showing the operation of warning output and display when the servo lock state is stopped in the servo control device according to the present invention.

FIG. 8 is a block diagram showing a second embodiment of a servo system including a servo control device according to the present invention.

FIG. 9 is a block diagram of a servo system including a conventional servo control device.

FIG. 10 is a graph showing an inverter output current during rotation.

FIG. 11 is a graph showing an inverter output current when the servo lock state is stopped.

[Explanation of symbols]

1 Servo Motor, 2 Detector, 3 Motor Cooling Fan, 5 AC Power Supply, 11 Power Converter, 13 Display, 1
4 converter part, 15 smoothing capacitor, 16 inverter part, 17 inverter cooling fan, 21 position control circuit, 22 speed calculation circuit, 23 speed control circuit, 24
Current control circuit, 30 controller, 121 positioning detection circuit, 122 positioning load detection circuit, 123
Positioning time detection circuit, 124 positioning frequency memory, 125 positioning load memory, 126 positioning time memory, 127 warning output circuit, 128 inverter section, 129 fan control circuit.

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Claims (7)

(57) [Claims] Detection means 1. A servo motor detects that it has stopped in the servo lock state at each position within one revolution, the number of the stop corresponding to the respective positions are warning output if the number of stops specified value servo controller, characterized in that it comprises a means. 2. The amount of heat generated by the inverter when stopped in the servo lock state is calculated from the current value and the time when stopped during the servo lock, and the temperature rise amount of the inverter is estimated from the amount of heat generated and estimated. The predetermined value of the number of times of stop is set according to the amount of temperature increase that has been performed.
The servo control device described in. 3. A detection means for detecting that the servo motor has stopped at each position within one rotation in a servo lock state, and outputs a warning if the stop time corresponding to each position reaches a specified stop time value. servo controller, characterized in that it comprises a means. 4. The heat generation amount of the servo motor when stopped in the servo lock state is calculated from the current value and the time when stopped in the servo lock state, and the temperature rise amount of the servo motor is estimated from the heat generation amount and estimated. 4. The predetermined stop time value is set according to the amount of temperature increase that has been performed.
The servo control device described in. 5. A lock is provided when stopping in the servo lock state.
5. A means for outputting a warning when the servo motor current value reaches a specified current value is further provided .
The servo control device according to any one of claims. 6. The servo control device according to claim 1, wherein the number of rotations of the motor cooling fan is increased when a warning is output. 7. The servo control device according to claim 1, wherein the rotation speed of the inverter cooling fan is increased when a warning is output.