JP2006254549A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller equipped with an electronic thermal function, capable of rapid restart after motor stopping while positively performing overheat protection of a motor. <P>SOLUTION: A CPU4 calculates a first estimated detection temperature reset at an initial value approximate to an allowable temperature as a second reference temperature on the basis of a power input, and calculates a second estimated detection temperature reset at an initial value lower than a first reference temperature judged to be in overheat state. Moreover, the CPU4, when it judges that the first estimated detection temperature is in excess of the second reference temperature, stops the motor 1 and protects the motor from overheat. Furthermore, the CPU4 restarts driving of the motor 1 by a power input and, if the second estimated detection temperature is lower than the first reference temperature, the CPU4 drives the motor 1 in a standard cycle time and, if the second estimated detection temperature is higher than the first reference temperature, drives the motor 1 in a set cycle time set so as to be longer than the standard cycle time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor control device that is suitable mainly for overheating protection of a motor.

  The motor may overheat due to various factors such as long-term use and overload, and this overheating causes inconvenience such as burning of the motor. Therefore, it is necessary to protect the motor from overheating. For such overheat protection, conventionally, the heat generation temperature of the motor is estimated from the result of the temperature simulation calculation process based on the motor current value, the motor rotation speed, etc., and the estimated detection temperature is an allowable temperature determined for each motor. A so-called electronic thermal is known in which a motor is stopped or an alarm is issued when (the upper limit temperature set for avoiding motor burnout) is exceeded (see, for example, Patent Document 1).

  In this prior art, in order to prevent the motor from being stopped as much as possible, when the estimated detected temperature exceeds a reference temperature (first reference temperature d1 in Patent Document 1) set to a temperature lower than the allowable temperature. The motor is driven by switching to a set cycle time longer than the standard cycle time. In other words, the motor is cooled while continuing to drive the motor by suppressing the rotational speed of the motor by driving with the set cycle time. Further, when the estimated detection temperature exceeds the allowable temperature (second reference temperature d2 in Patent Document 1), the motor is permitted to be driven when the estimated detection temperature falls below the reference temperature when the power is turned on next time. It has become so.

  By the way, the calculation of the estimated detection temperature described above is started when the motor drive power is turned on. However, as a countermeasure in the case where an inexpensive system that does not back up the detection temperature of the motor in the memory is employed, The calculation is started using the initial value close to the temperature. By setting the initial value of the estimated detection temperature close to the allowable temperature, even if the temperature of the motor at the time of power shut-off is unknown because there is no backup function, it is possible to detect the motor overheating condition immediately after the power is turned on. Because.

Therefore, when the power is turned on, the motor is driven at the set cycle time when the estimated detection temperature falls below the second reference temperature (the third reference temperature d3 in Patent Document 1) set lower than the reference temperature. To normal cycle time. That is, it takes time from when the motor is turned on until the motor enters the normal rotation state. Further, when the estimated detection temperature exceeds the allowable temperature and the motor is stopped, the motor is turned on next time, and the estimated detection temperature does not fall below the second reference temperature (third reference temperature d3). In this case, it takes time for the motor to be in a normal rotation state after the power is turned on. For this reason, in the production line using the motor controlled in this way, the situation that the time until the normal operation state is reached occurs, and the productivity is lowered.
JP-A-11-341850

  The main object of the present invention is to provide a motor control device that enables quick restart after stopping the motor while ensuring overheat protection of the motor in a motor control device having an electronic thermal function. is there.

  Hereinafter, effective means for solving the above-described problems will be described while showing effects and the like as necessary. In the following, in order to facilitate understanding, the corresponding configuration in the embodiment of the invention is appropriately shown in parentheses, but is not limited to the specific configuration shown in parentheses.

Means 1. Current detection means (current sensors 12, 13) for detecting the drive current of the motor (motor 1);
Estimated temperature calculation means for calculating the heat generation temperature of the motor as the estimated detection temperature (first estimated detection temperature DH, second estimated detection temperature DL) based on the current detected by the current detection means (processing of step S101 of the CPU 4) Function)
When the estimated detected temperature calculated by the estimated temperature calculating means exceeds an allowable temperature (second reference temperature d2) for stopping the motor due to overheating, motor stop control means for stopping the motor (in step S108 of the CPU 4). Processing function), and
The estimated detected temperature calculated by the estimated temperature calculating means is compared with a reference temperature (first reference temperature d1) set lower than the allowable temperature, and when the estimated detected temperature is lower than the reference temperature, the motor Drive control means (step S103 of the CPU 4) for intermittently driving the motor at a set cycle time set longer than the standard cycle time when the estimated detected temperature is higher than the reference temperature. , 106 processing function),
The estimated temperature calculating means includes
First estimated temperature calculation means for calculating a first estimated detected temperature (first estimated detected temperature DH) using a first initial value (65 ° C.) that is equal to or lower than the allowable temperature when the power is turned on (in step S101 of the CPU 4). Processing function), and
Second estimated temperature calculation means (CPU 4) that calculates a second estimated detected temperature (which is a second estimated detected temperature DL) using a second initial value (0 ° C.) that is lower than the first initial value based on power-on. Processing function of step S101),
The motor stop control means compares the first estimated detected temperature with the allowable temperature to determine whether to stop the motor (determination process in step S107 of the CPU 4),
The drive control means starts driving the motor when the power is turned on, and performs drive control of the motor by comparing the second estimated detected temperature with the reference temperature (in steps S102, S103, and S106 of the CPU 4). A motor control device.

  According to the means 1, the first estimated temperature calculating means calculates the first estimated detected temperature that is reset to the first initial value based on the power-on, and the second estimated temperature calculating means calculates the first initial temperature based on the power-on. A second estimated detected temperature that is reset to a second initial value that is lower than the value is calculated. When the motor stop control means determines that the first estimated detected temperature exceeds the allowable temperature, the motor stop control means stops the motor. On the other hand, the drive control means starts driving the motor when the power is turned on. When the second estimated detected temperature is lower than the reference temperature, the drive is intermittently driven with the standard cycle time, and the second estimated detected temperature is set as the reference. When the temperature is higher, the motor is intermittently driven at a set cycle time set longer than the standard cycle time.

  As a result, since the first estimated detected temperature changes from the first initial value on the side closer to the allowable temperature of the motor based on the power-on, it is possible to detect the motor overheating state immediately after power-on. Therefore, motor stop control due to overheating can be performed more reliably.

  Further, since the second estimated detected temperature changes from a temperature lower than the first initial value, the drive control means can restart the driving of the motor as soon as the power is turned on. Therefore, it is possible to improve the startability of the motor after the power is turned on.

  In this way, so-called electronic thermals with different initial values are provided twice, the higher initial value contributes to motor overheat protection, and the lower initial value contributes to motor startability improvement. It is possible to achieve both improvement in motor startability.

  Mean 2. The motor control device according to claim 1, wherein the first initial value of the first estimated temperature calculation means is set as a value close to the allowable temperature.

  According to the means 2, the overheat protection effect of the motor can be further ensured by setting the first initial value of the first estimated detected temperature contributing to the motor stop control to a value close to the allowable temperature.

  Means 3. The motor control device according to claim 1 or 2, wherein the second initial value of the second estimated temperature calculation means is set as a value equal to or lower than the reference temperature.

  According to the means 3, the second initial value of the second estimated detected temperature that contributes to improving the startability of the motor is set to a value equal to or lower than the reference temperature, so that preparation for resuming operation of the motor is completed from the beginning of power-on. As a result, the startability of the motor can be further improved.

  Means 4. Both the first and second estimated temperature calculating means are configured to calculate the estimated detected temperature by using the same arithmetic expression with only the initial values of the first and second estimated detected temperatures being different from each other. The motor control apparatus in any one.

  According to the means 4, since the calculation processing of both the first and second estimated temperature calculation means is the same processing except for the initial value, it is possible to share a program such as an arithmetic expression, and the software of the motor control device Design becomes easy.

  Means 5. 2. The motor control apparatus according to claim 1, further comprising temperature setting means (first temperature setting switch 27, second temperature setting switch 28) for adjusting and setting at least one of the allowable temperature and the reference temperature.

  According to the means 5, the temperature at which the motor should be stopped and the temperature at which the cycle time should be switched can be adjusted according to the use environment of the motor and the situation at the work site.

  Means 6. 2. The motor control apparatus according to claim 1, further comprising cycle time setting means (cycle time setting switch 30) for adjusting and setting the set cycle time.

  According to the means 6, if the set cycle time is adjusted to be increased, the motor overheat state can be immediately eliminated, and the set cycle time is adjusted to be shortened within a range not shorter than the normal cycle time. If this is done, it takes time to eliminate the motor overheating state, but the reduction in work efficiency can be minimized. In the case of driving the motor intermittently, it is preferable to adjust the cycle time by adjusting the motor rotation speed from the viewpoint of avoiding an overheated state.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. First, a circuit configuration will be described based on a block circuit diagram centering on a motor control circuit for driving and controlling the motor 1 shown in FIG.

  The motor 1 is constituted by a three-phase induction motor in the present embodiment. A resolver 2 is connected to the motor 1, and the resolver 2 detects the number of rotations of the motor 1 and outputs a resolver signal that is a rotation detection signal. An R / D converter 3 is connected to the resolver 2, and the R / D converter 3 converts a resolver signal from the resolver 2 into a digital signal. A CPU 4 is connected to the R / D converter 3, and a digital signal that is a rotation detection signal from the R / D converter 3 is input to the CPU 4.

  Connected to the CPU 4 are a ROM 5 that stores a control program for intermittently driving the motor 1 with a predetermined standard cycle time, and a RAM 6 that temporarily stores various information. In the present embodiment, the RAM 6 is composed of an inexpensive volatile memory such as a DRAM, so that stored data is erased when the power is turned off. The RAM 6 sequentially stores the rotation speed of the motor 1 obtained based on the rotation detection signal from the resolver 2.

  A current control circuit 7 is connected to the CPU 4, and a current command signal output from the CPU 4 is input to the current control circuit 7. An inverter circuit 8 is connected to the output side of the current control circuit 7. The motor 1 is connected to the U, V, W current supply lines 9, 10, 11 connected to the output side of the inverter circuit 8. The U-phase current supply line 9 and the V-phase current supply line 10 are provided with current sensors 12 and 13, respectively. A current sensor 12 corresponding to the U-phase current supply line 9 detects the U-phase current level of the motor 1 and outputs a U-phase current signal to the signal line 14. The current sensor 13 corresponding to the V-phase current supply line 10 detects the V-phase current level of the motor 1 and outputs a V-phase current signal to the signal line 15.

  Both signal lines 14 and 15 are connected to the current control circuit 7 and feed back the U-phase current signal and the V-phase current signal to the current control circuit 7. Both signal lines 14 and 15 are connected to branch signal lines 16 and 17, respectively, and both branch signal lines 16 and 17 are connected to the input side of the W-phase current converter 18. The W-phase current converter 18 converts the W-phase current level from the U-phase current signal and the V-phase current signal and outputs a W-phase current signal. The signal line 19 connected to the output side of the W-phase current converter 18 is connected to the current control circuit 7 and feeds back the W-phase current signal to the current control circuit 7.

  The signal lines 14, 15, and 19 are further connected to a common adder 21 via a diode 20, and are added after half-wave rectification of each phase current signal. The adder 21 is connected to the CPU 4 via the A / D converter 22. Therefore, the A / D converter 22 outputs a digital signal corresponding to the total current signal obtained by the addition to the CPU 4. The total current is sequentially stored in the RAM 6.

  The ROM 5 stores a temperature simulation formula corresponding to the type of the motor 1 being used. Further, as described above, the total current and the rotation speed of the motor 1 are sequentially stored in the RAM 6. Then, the CPU 4 calculates the estimated detected temperature of the motor 1 by applying these values stored in the RAM 6 to the temperature simulation calculation formula stored in the ROM 5. Since the temperature simulation itself is a general technique in electronic thermal, its detailed description is omitted.

  Here, in the present embodiment, the CPU 4 calculates the estimated detection temperature of the motor 1 in a double manner as the first estimated detection temperature DH and the second estimated detection temperature DL. The first estimated detection temperature DH is set to an initial value of 65 ° C. when the power is turned on, and the calculation is started using this initial value. The second estimated detection temperature DL has an initial value set to 0 ° C. when the power is turned on, and the same calculation as the first estimated detection temperature DH is started using this initial value. That is, the first estimated detection temperature DH and the second estimated detection temperature DL differ only in the initial value used as the estimated detection temperature, and the calculation formula itself is exactly the same. The CPU 4 stores the first and second estimated detection temperatures DH and DL in the RAM 6 each time. Since the RAM 6 erases stored data when the power is turned off, the data of the detected temperatures DH and DL are also erased when the power is turned off.

  The current control circuit 7 outputs a current command signal for intermittently driving the motor 1 output from the CPU 4 with a predetermined cycle time, and signals relating to the current value actually flowing to the motor 1 (U-phase current signal, V-phase current signal). Current signal and W-phase current signal) and a control signal is output to the inverter circuit 8 so that the current that actually flows through the motor 1 matches the current command signal. The inverter circuit 8 adjusts the current supplied to each of the current supply lines 9, 10, 11 in accordance with the control signal from the current control circuit 7, and intermittently drives the motor 1 so as to match the current command signal from the CPU 4. Let

  A sequencer 24 is connected to the CPU 4 via an input / output interface 23 so that bidirectional communication is possible. The sequencer 24 drives peripheral devices in synchronization with the intermittent drive of the motor 1, and a sequencer control signal is output from the CPU 4 to the sequencer 24. On the other hand, detection signals and the like of peripheral devices are output from the sequencer 24 to the CPU 4. By such bi-directional communication, synchronization between the motor 1 and peripheral devices is realized.

  The alarm device 25, the start switch 26, the first temperature setting switch 27, the second temperature setting switch 28, and the cycle time setting switch 30 are connected to the CPU 4 via the input / output interface 23.

  The alarm device 25 performs an alarm operation for transmitting a predetermined situation to an external worker based on an alarm signal from the CPU 4, and stops the alarm operation based on an alarm reset signal from the CPU 4.

  The start switch 26 is a changeover switch that is turned on and off by an operator, and outputs an on signal or an off signal to the CPU 4 in accordance with the changeover state. When the start switch 26 is turned on, power supply to each unit is started, and the CPU 4 enters an operating state.

  The first temperature setting switch 27 is a variable volume operated to arbitrarily adjust the first reference temperature d1 by an operator, and outputs a signal related to the first reference temperature d1 to the CPU 4 according to the adjustment state. Similarly, the second temperature setting switch 28 is a variable volume operated to arbitrarily adjust the second reference temperature d2 by an operator, and a signal related to the second reference temperature d2 is sent to the CPU 4 according to the adjustment state. Output. The first reference temperature d1 and the second reference temperature d2 are stored in the RAM 6.

  Here, the first and second reference temperatures d1 and d2 will be described. The second reference temperature d2 is an allowable temperature of the motor 1, and if the actual temperature of the motor 1 exceeds this, the motor 1 may be burned out. Is the limit temperature to be used. Therefore, the second reference temperature d2 can be grasped in advance according to the type and size of the motor 1. The second reference temperature d2 of the motor 1 in the present embodiment is set to 70 ° C., for example.

  On the other hand, the first reference temperature d1 is set to a value lower than the second reference temperature d2, and the actual temperature of the motor 1 is caused by factors such as long-term continuous use of the motor 1 and temporary load increase. Is set as a possibility of temporarily exceeding. In other words, the first reference temperature d <b> 1 is a temperature for determining that the motor 1 needs to be cooled although the operation of the motor 1 may continue even though the temperature is lower than the allowable temperature. The first reference temperature d1 is a reference for switching the cycle time of the motor 1. The first reference temperature d1 is also used to determine that the motor 1 has been sufficiently avoided from the overheated state. In the present embodiment, the first reference temperature d1 is set to 40 ° C., for example.

  The cycle time setting switch 30 is a variable volume operated to arbitrarily adjust the set cycle time of the motor 1 by an operator, and outputs a signal related to the set cycle time to the CPU 4 according to the adjustment state. More specifically, the value adjusted by the cycle time setting switch 30 contributes to the rotation speed of the motor 1 being lower than that of the normal time, and the cycle time set thereby is higher than the standard cycle time. It will be long. The set cycle time set by the cycle time setting switch 30 is stored in the RAM 6. Then, the CPU 4 selects either a current command signal corresponding to the standard cycle time or a current command signal corresponding to the set cycle time according to the heat generation state of the motor.

  Next, the motor control process of the CPU 4 will be described with reference to the waveform diagram of FIG. 2 and the flowchart of FIG. The CPU 4 executes the motor control process of FIG. 3 when the start switch 26 is turned on, and the motor control process is repeated every predetermined time.

  When the start switch 26 is turned on to start operation of the production line including the motor 1, calculation of the first and second estimated detected temperatures DH and DL is started in step S101. For the first estimated detection temperature DH, the simulation calculation of the estimated detection temperature is started with an initial value of 65 ° C., and for the second estimated detection temperature DL, the simulation calculation of the estimated detection temperature is started with an initial value of 0 ° C. The first and second estimated detection temperatures DH and DL are initially estimated temperatures (0 ° C. and 65 ° C.) that are largely separated due to the difference in the initial values, but gradually approach the actual temperature from here, As shown in FIG. 2, they converge with each other as time passes, and change substantially in the same manner after convergence. If there is no abnormality in the motor 1, it is assumed that the first and second estimated detection temperatures DH and DL are lower than the first reference temperature d1 (40 ° C.).

  In step S102, it is determined whether the second estimated detection temperature DL is higher than the first reference temperature d1 (40 ° C.). If it is determined that the second estimated detection temperature DL is equal to or lower than the first reference temperature d1, the process proceeds to step S103.

  In step S103, the motor 1 is intermittently driven with a standard cycle time. In addition, a sequencer control signal corresponding to the standard cycle time is output to the sequencer 24, and the peripheral device is driven in synchronization with the motor 1. Therefore, unless the second estimated detection temperature DL is higher than the first reference temperature d1 (40 ° C.), that is, in the period from time t0 to time t1 in FIG. 2 or in the period from time t2 to time t3, the motor 1 It will be operated with standard cycle time.

  In the next step S104, if an alarm is output in the previous process, an alarm reset signal is output to the alarm device 25, and the alarm operation of the alarm device 25 is stopped. Then, the motor control process ends.

  If it is determined in step S102 that the second estimated detected temperature DL has exceeded the first reference temperature d1 (40 ° C.), the process proceeds to step S105. In step S105, an alarm signal is output to the alarm device 25 to cause the alarm device 25 to perform an alarm operation.

  In the next step S106, the motor 1 is intermittently driven at a set cycle time. In addition, a sequencer control signal corresponding to the set cycle time is output to the sequencer 24 to drive the peripheral device in synchronization with the motor 1. That is, in FIG. 2, in the period from time t1 to time t2 or in the period from time t3 to time t4, the alarm operation by the alarm device 25 is performed and the motor 1 is operated at the set cycle time.

  That is, by driving the motor 1 with a set cycle time set longer than the standard cycle time, the motor 1 is cooled while being driven, and the production line is not stopped as much as possible. Further, when the motor 1 is driven at the set cycle time and the second estimated detected temperature DL becomes equal to or lower than the first reference temperature d1 (40 ° C.) (time t2 in FIG. 2), the motor 1 is driven again at the standard cycle time. It is supposed to be.

  Next, in step S107, it is determined whether or not the first estimated detection temperature DH is higher than the second reference temperature d2 (70 ° C.). If it is determined that the first estimated detection temperature DH is equal to or lower than the second reference temperature d2 (70 ° C.), the motor control process is terminated while the drive of the motor 1 is maintained.

  On the other hand, if it is determined that the first estimated detected temperature DH exceeds the second reference temperature d2 (70 ° C.), the process proceeds to step S108. In step S108, in order to protect the motor 1 from abnormal overheating, the driving of the motor 1 is stopped (time t4 in FIG. 2). When the motor 1 is stopped, the motor 1 is naturally cooled. In addition, when the motor 1 is stopped, the operator can search for the cause of the abnormal overheating of the motor 1 and remove the cause.

  This stop state of the motor 1 is continued unless the start switch 26 is turned on again. When the start switch 26 is turned on again, the processing is sequentially executed from the step S101. When the start switch 26 is turned on again in this way, the data stored in the RAM 6 is erased, so that the first estimated detection temperature DH and the second estimated detection temperature DL are both 65 ° C. and 0 which are initial values. The state is reset to ° C. (time t5 in FIG. 2).

  As described above, in the present embodiment, the CPU 4 resets the first estimated detection temperature DH to the initial value (65 ° C.) close to the second reference temperature d2 (70 ° C.), which is the allowable temperature, when the power is turned on. Is calculated, and the first estimated detected temperature DL is reset to the initial value (0 ° C.) lower than the first reference temperature d1 (40 ° C.) when the power is turned on together with the calculation of the first estimated detected temperature DH. Is calculated. If the CPU 4 determines that the first estimated detected temperature DH exceeds the second reference temperature d2, the CPU 4 stops the motor 1. On the other hand, the CPU 4 drives the motor 1 at the standard cycle time when the second estimated detected temperature DL is lower than the first reference temperature d1, and the motor 4 when the second estimated detected temperature DL is higher than the first reference temperature d1. 1 is driven with a set cycle time set longer than the standard cycle time.

  Therefore, according to the present embodiment, the following excellent effects can be obtained.

  That is, since the first estimated detection temperature DH changes from the initial value near the second reference temperature d2 of the motor 1 based on power-on, the overheated state of the motor 1 can be detected immediately after power-on. Therefore, motor stop control due to overheating can be performed more reliably.

  Further, since the second estimated detection temperature DL changes from a value lower than the first reference temperature d1, the motor 1 can be driven at the standard cycle time as soon as the power is turned on. Therefore, the startability of the motor 1 when the power is turned on can be improved. As a result, in a production line using such a motor 1, the time until the normal operation state is reached is shortened, and the productivity can be improved.

  That is, in the present embodiment, the estimated detection temperature of the motor 1 is a double of a first estimated detection temperature DH having a relatively high temperature as an initial value and a second estimated detection temperature DL having a relatively low temperature as an initial value. Thus, the temperature simulation calculation is executed in this manner, so that both protection of the motor 1 due to overheating and improvement of the startability of the motor 1 can be achieved.

  Such an advantage becomes particularly prominent when some foreign matter bites into the output side of the motor 1 and is temporarily estimated to be in an overheated state. In this case, the estimated detection temperature is actually only temporarily increased due to overload (the actual temperature is not actually high), but in the conventional electronic thermal in which the estimated detection temperature of 1 is obtained. This is because if the initial value is relatively high, the motor 1 could not be started until the estimated detected temperature was lowered to the actual temperature. Note that, in the conventional type in which the estimated detection temperature of 1 is obtained, setting the initial value to a relatively low temperature may exceed the allowable temperature of the motor 1 when the actual temperature is high. Thus, this is an unexpected setting.

  In the present embodiment, the CPU 4 calculates the first and second estimated detected temperatures DH and DL by the same calculation while changing only the initial values. Therefore, the same temperature simulation arithmetic expression used for calculating each estimated detection temperature can be used, and the common use of the program can be promoted.

  In the present embodiment, the initial value of the second estimated detection temperature DL may be set to 0 ° C. Therefore, it is not necessary to consider individual differences of the motor 1 when setting the initial value of the second estimated detection temperature DL, and the versatility is high.

  In the present embodiment, when the second estimated detection temperature DL is higher than the first reference temperature d1, an alarm device 25 is provided that outputs an alarm to notify the outside. As a result, the alarm device 25 informs the operator that the motor 1 is being driven with a longer cycle time than normal, so that the cause of heat generation is investigated before the motor 1 is stopped. It can be performed.

  In the present embodiment, when the second estimated detection temperature DL is lower than the first reference temperature d1, the alarm output by the alarm device 25 is automatically stopped. Thereby, the operator can understand that the drive of the motor 1 has returned to the drive with the cycle time at the normal time.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  In the above embodiment, the alarm output by the alarm device 25 is executed on condition that the second estimated detection temperature DL is higher than the first reference temperature d1, but the first estimated detection temperature DH is further set to the second reference temperature d1. When the temperature is higher than the temperature d2, the alarm output by the alarm device 25 may be executed in a different manner. This can be realized by adding a process for outputting an alarm for notifying the motor stop immediately before or after step S108 in FIG. And if comprised in this way, according to the mode of the alarm by the alarm device 25, an operator can be made to understand whether it is driving by setting cycle time or the motor 1 stopped.

  In the above embodiment, the initial value of the second estimated detection temperature DL is set to 0 ° C., but the initial value can be arbitrarily set lower than the first reference temperature d1. For example, it is preferable to set the initial value to any temperature within a predetermined temperature range that is reached when the motor 1 is normally driven at the standard cycle time. That is, since the second estimated detected temperature DL is the temperature at which the motor 1 is normally driven at the standard cycle time from the beginning of power-on, the second estimated detected temperature DL is quickly approximated to the actual temperature of the motor 1. Can be made.

  Furthermore, the initial value of the second estimated detection temperature DL may be higher than the first reference temperature d1, and it is only necessary to be set at a temperature lower than at least the initial value (65 ° C.) of the first estimated detection temperature DH. . This is because, as long as the initial value of the second estimated detection temperature DL is set lower than the initial value of the first estimated detection temperature DH, it is earlier than the case where only the first estimated detection temperature DH is used as the estimated detection temperature. This is because the motor 1 can be returned to normal operation. For example, the initial value of the second estimated detected temperature DL is set to a temperature slightly higher than the first reference temperature d1, and the motor 1 is operated when the second estimated detected temperature DL becomes lower than the first reference temperature d1. By restarting, it is possible to reliably avoid a situation in which the motor 1 resumes operation when the motor 1 is in an overheated state.

  In the above embodiment, the reference temperature for switching the cycle time of the motor 1 is one of the first reference temperatures d1, but a plurality of reference temperatures may be provided. For example, when two reference temperatures for switching the cycle time of the motor 1 are used, such as an upper reference temperature and a lower reference temperature, and the second estimated detection temperature DL becomes higher than the upper reference temperature, the set cycle starts from the standard cycle time. When the driving of the motor 1 is switched at the time, and the driving is performed at the set cycle time, when the second estimated detection temperature DL becomes lower than the lower reference temperature, the motor 1 is returned to the standard cycle time. By setting such hysteresis, the problem of frequently going back and forth between the standard cycle time and the set cycle time is solved.

  In the above embodiment, the first reference temperature d1, the second reference temperature d2, and the set cycle time can be adjusted by the first temperature setting switch 27, the second temperature setting switch 28, and the cycle time setting switch 30, respectively. At least one of the first reference temperature d1, the second reference temperature d2 and the set cycle time is stored in advance in a storage means such as an EEPROM, and the corresponding setting switches 27, 28 and 30 are omitted. Also good.

  In the above embodiment, after the motor 1 is stopped due to overheating (step S108), the restart operation by the start switch 26 is required. However, this operation is not necessary and only the temperature may be used as the restart condition. In this case, since the operator only needs to remove the cause of overheating, the operation for starting the motor 1 is completely unnecessary.

  In the above embodiment, the rotational speed of the motor 1 is slowed down in order to increase the cycle time. In addition to this, for example, the rotational speed of the motor 1 is the same as in the case of the standard cycle time. The stop time of the motor 1 may be lengthened. In this case, the stop time may be adjusted by the cycle time setting switch 30.

  In the above embodiment, the rotation of the motor 1 is detected by the resolver 2, but other rotation detection means such as a rotary encoder may be used.

  In the above-described embodiment, the output current of the inverter circuit 8 is fed back to adjust the output. However, an inverter circuit that does not perform feedback control may be used.

  In the said embodiment, although implemented to the three-phase type motor 1, you may implement not only this but the motor of a two-phase type or a 4-phase or more type. The motor 1 may be implemented for any type of motor such as a DD motor, a brushless motor, or an AC motor.

The block circuit diagram of a motor and a motor control apparatus. The waveform diagram which illustrates the time change of estimated detection temperature. The flowchart for demonstrating a motor control process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor, 4 ... CPU (estimated temperature calculation means, motor stop control means, and drive control means), 12, 13 ... Current sensor (current detection means), 27, 28 ... First and second temperature setting switches (Temperature setting means) ), 30 ... cycle time setting switch (cycle time setting means), DH ... first estimated detection temperature (estimated detection temperature), DL ... second estimated detection temperature (estimated detection temperature), d1 ... first reference temperature (reference temperature) ), D2... Second reference temperature (allowable temperature).

Claims (6)

Current detection means for detecting the drive current of the motor;
Estimated temperature calculating means for calculating the heat generation temperature of the motor as the estimated detected temperature based on the current detected by the current detecting means;
Motor stop control means for stopping the motor when the estimated detected temperature calculated by the estimated temperature calculating means exceeds an allowable temperature for stopping the motor due to overheating;
The estimated detected temperature calculated by the estimated temperature calculating means is compared with a reference temperature set lower than the allowable temperature. When the estimated detected temperature is lower than the reference temperature, the motor is intermittently driven at a standard cycle time. A motor control device comprising drive control means for intermittently driving the motor at a set cycle time set longer than the standard cycle time when the estimated detected temperature is higher than the reference temperature;
The estimated temperature calculating means includes
First estimated temperature calculation means for calculating a first estimated detected temperature using a first initial value that is equal to or lower than the allowable temperature based on power-on;
Second estimated temperature calculating means for calculating a second estimated detected temperature using a second initial value that is lower than the first initial value based on power-on,
The motor stop control means compares the first estimated detection temperature with the allowable temperature to determine whether to stop the motor,
The motor control device is characterized in that the drive control means starts driving of the motor when power is turned on, and performs drive control of the motor by comparing the second estimated detected temperature with the reference temperature.   The motor control device according to claim 1, wherein the first initial value of the first estimated temperature calculation means is set as a value close to the allowable temperature.   3. The motor control device according to claim 1, wherein the second initial value of the second estimated temperature calculation means is set as a value equal to or lower than the reference temperature.   The first and second estimated temperature calculation means respectively calculate the estimated detection temperature by using the same arithmetic expression while changing only the initial values of the first and second estimated detection temperatures. The motor control apparatus in any one.   The motor control device according to claim 1, further comprising temperature setting means for adjusting and setting at least one of the allowable temperature and the reference temperature.   The motor control device according to claim 1, further comprising cycle time setting means for adjusting and setting the set cycle time.

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