JP6767963B2 - Motor control device and motor control method - Google Patents

Description

The present invention relates to a motor control device and a motor control method, which have a control unit that generates a drive command to the motor.

In the conventional control device, temperature, humidity, and atmospheric pressure are detected, and the motor is controlled based on the detected values to prevent the motor from generating a partial discharge (see, for example, Patent Document 1). ..

Japanese Unexamined Patent Publication No. 2017-073926

However, the prior art has the following problems.
As described above, the conventional control device does not consider the water absorption of the insulating material when controlling the motor. As a result, there is a problem that the motor output is limited more than necessary due to restrictions on voltage, temperature, and the like.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a motor control device and a motor control method capable of relaxing the output limitation of the motor as compared with the conventional case.

The motor control device in the present invention includes a control unit that generates a drive command to the motor, a temperature sensor that detects the temperature of the winding of the motor, and a specific dielectric constant calculation unit that calculates the specific dielectric constant of the insulating material of the motor. , Partial discharge start voltage calculation to calculate the partial discharge start voltage corresponding to the voltage value at which partial discharge starts in the motor based on the temperature detected by the temperature sensor and the specific dielectric constant calculated by the specific dielectric constant calculation unit. Comparing the applied voltage corresponding to the voltage applied to the unit and the motor with the partial discharge start voltage, if the partial discharge start voltage is lower than the applied voltage, it is determined that the partial discharge occurs. The control unit includes at least one of a command for lowering the applied voltage and a command for lowering the output of the motor when the partial discharge generation determination unit determines that a partial discharge is generated. Is generated as a drive command to control the motor, and when it is determined by the partial discharge generation determination unit that partial discharge does not occur, a command to maintain the applied voltage is generated as a drive command to control the motor. is there.

Further, the motor control method in the present invention is a motor control method in which a motor is driven and controlled by a motor control device, which includes a temperature detection step of detecting the temperature of the winding of the motor via a temperature sensor in the motor control device. A partial discharge occurs in the motor based on the relative dielectric constant calculation step for calculating the relative dielectric constant of the insulating material of the motor, the temperature detected by the temperature detection step, and the specific dielectric constant calculated by the specific dielectric constant calculation step. The partial discharge start voltage calculation step for calculating the partial discharge start voltage corresponding to the starting voltage value is compared with the applied voltage corresponding to the voltage applied to the motor and the partial discharge start voltage, and the partial discharge start voltage is calculated from the applied voltage. When the value is also low, the partial discharge generation determination step for determining that a partial discharge is generated, and the first drive command for lowering the applied voltage when it is determined by the partial discharge generation determination step that a partial discharge is generated, And when it is determined by the first control step that controls the motor and the partial discharge generation determination step that the partial discharge does not occur by generating at least one drive command of the second drive command that lowers the output of the motor. It has a second control step that generates a drive command for maintaining the applied voltage and controls the motor.

According to the motor control device and the motor control method according to the present invention, the partial discharge start voltage is obtained from the calculation result of the relative permittivity of the insulating member of the motor, and the motor is controlled based on the change in the partial discharge start voltage. are doing. As a result, it is possible to obtain a motor control device and a control method capable of relaxing the output limitation of the motor as compared with the conventional case.

It is a block diagram which shows the structure of the motor control device which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the partial discharge start voltage which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the partial discharge start voltage which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the capacitance which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the capacitance which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the partial discharge start voltage which concerns on Embodiment 1 of this invention. It is a figure which showed an example of the measurement result of the partial discharge start voltage which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the motor control device which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the motor control device which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the motor control device which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the motor control device which concerns on Embodiment 5 of this invention. It is a figure which showed an example of the measurement result of the partial discharge start voltage which concerns on Embodiment 5 of this invention. It is a flowchart which shows the series process of the motor control apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the series process of the motor control apparatus which concerns on Embodiment 4 of this invention.

Hereinafter, preferred embodiments of the motor control device and the motor control method of the present invention will be described with reference to the drawings.

Embodiment 1.
FIG. 1 is a block diagram showing a configuration of a motor control device 1 according to a first embodiment of the present invention. The motor control device 1 according to the first embodiment includes a temperature sensor 10, a relative permittivity calculation unit 20, a partial discharge start voltage calculation unit 30, a partial discharge generation determination unit 40, and a control unit 50. ..

The temperature sensor 10 detects the temperature of the winding of the motor 100. For example, the temperature sensor 10 is provided in contact with a conducting wire forming a winding. The temperature of the winding in the motor detected by the temperature sensor 10 is sent to the relative permittivity calculation unit 20 and the partial discharge start voltage calculation unit 30.

The relative permittivity calculation unit 20 calculates the relative permittivity of the insulating material used in the motor 100 based on the temperature detected by the temperature sensor 10. The calculated relative permittivity is sent to the partial discharge start voltage calculation unit 30.

A specific example of a method for calculating the relative permittivity of the insulating material used in the motor 100 will be described. As an example, when the cooling oil circulates in the motor, the relative permittivity of the insulating material of the motor is calculated from the relative permittivity or the insulating resistance when the cooling oil is passed between the electrodes of the parallel flat plate. It is possible.

In addition, the insulating paper or insulating film used for the insulating material of the motor is sandwiched between the parallel flat plates, and the relative permittivity of the insulating material of the motor is calculated from the relative permittivity or the insulating resistance of the insulating paper. It is also possible.

The partial discharge start voltage calculation unit 30 determines the partial discharge start voltage of the motor based on the winding temperature detected by the temperature sensor 10 and the relative permittivity of the insulating material calculated by the relative permittivity calculation unit 20. Is calculated. The calculated partial discharge start voltage is sent to the partial discharge generation determination unit 40.

The value of the partial discharge start voltage changes depending on the relative permittivity and the temperature. Therefore, the partial discharge start voltage calculation unit 30 calculates the value of the partial discharge start voltage by using the relative permittivity and the temperature. A specific method for calculating the value of the partial discharge start voltage, which is performed by the partial discharge start voltage calculation unit 30, will be described below.

It is assumed that the initial partial discharge start voltage is f0 when the initial winding temperature is a0 and the initial relative permittivity is b0. Here, the rate of change of the partial discharge start voltage due to temperature is f1 (a), and the rate of change of the partial discharge start voltage due to the relative permittivity is f2 (b). Under such a premise, the partial discharge start voltage f when the winding temperature is a1 and the relative permittivity is b1 is expressed by the following equation (1).
f = f0 × f1 (a1) × f2 (b1) (1)

The partial discharge start voltage calculation unit 30 calculates the partial discharge start voltage based on the above equation (1). The rate of change f1 (a) of the partial discharge start voltage due to the winding temperature and the rate of change f2 (b) of the partial discharge start voltage due to the dielectric constant are each acquired in advance by measurement or analysis and stored in the storage unit. It can be memorized. The storage unit is not shown.

The partial discharge generation determination unit 40 compares the value of the partial discharge start voltage calculated by the partial discharge start voltage calculation unit 30 with the voltage Vsurge applied to the motor 100, and when the voltage Vsurge is applied, the partial discharge occurs. Determine if it occurs.

Specifically, the partial discharge generation determination unit 40 compares the partial discharge start voltage f calculated by the partial discharge start voltage calculation unit 30 based on the equation (1) with the voltage Vsurge applied to the motor. Then, the partial discharge generation determination unit 40 determines that when the partial discharge start voltage f is equal to or lower than the voltage Vsurge, the partial discharge is generated when the voltage Vsurge is applied. On the other hand, when the partial discharge start voltage f is larger than the voltage Vsurge, the partial discharge generation determination unit 40 determines that the partial discharge does not occur when the voltage Vsurge is applied.

The determination result by the partial discharge generation determination unit 40 is sent to the control unit 50.

The control unit 50 controls the voltage Vsurge applied to the motor 100 and the output of the motor 100 based on the determination result of the partial discharge generation determination unit 40. That is, when the control unit 50 receives the determination result that the partial discharge is generated from the partial discharge generation determination unit 40, the control unit 50 executes one or both of the following controls.
-Control to lower the voltage Vsurge applied to the motor 100.
-Control that lowers the output of the motor 100 and lowers the temperature of the motor 100.

On the other hand, when the control unit 50 receives the determination result that the partial discharge does not occur from the partial discharge generation determination unit 40, the control of the motor 100 maintains the current state and applies a voltage Vsurge to the motor 100. Control the application.

A series of processes for determining the presence or absence of partial discharge from the calculation result of the temperature and the relative permittivity of the motor 100 and performing control according to the determination result are repeatedly executed by the control device 1 during the operation of the motor 100.

FIG. 2 is a diagram showing an example of the measurement result of the partial discharge start voltage according to the first embodiment of the present invention. More specifically, FIG. 2 shows the measurement result of the partial discharge start voltage when the stator is heated from 40 ° C. to 150 ° C. in a state where the motor stator is dry.

As shown in FIG. 2, the partial discharge start voltage decreases as the temperature of the motor 100 rises. From the result of FIG. 2, the partial discharge start voltage in the dry state of the stator can be specified by measuring the temperature of the motor 100.

On the other hand, the measurement result of the partial discharge start voltage in the state where the stator of the motor 100 has absorbed moisture will be described with reference to FIG. FIG. 3 is a diagram showing an example of the measurement result of the partial discharge start voltage according to the first embodiment of the present invention. More specifically, FIG. 3 shows the measurement results of the partial discharge start voltage when the hygroscopic stator is placed in a high humidity environment and the stator is heated from 40 ° C. to 150 ° C.

As shown in FIG. 3, the partial discharge start voltage decreases once with the increase in the temperature of the motor 100, and then starts to increase. That is, from the results shown in FIG. 3, the partial discharge start voltage in a state where the motor stator absorbs moisture in a high humidity environment is significantly affected by humidity and moisture absorption, and therefore can be specified only by measuring the temperature of the motor 100. Can not.

Further, at the time of measurement in FIG. 3, the humidity is kept constant in a high humidity environment. Therefore, even if the humidity is measured in addition to the temperature, the partial discharge start voltage cannot be specified. Therefore, in the first embodiment, by measuring the capacitance between the winding of the motor 100 and the core during heating, the stator absorbs moisture in a high humidity environment as shown in FIG. It is possible to specify the partial discharge start voltage in this state. Therefore, the characteristics of the capacitance will be described with reference to FIGS. 4 and 5.

FIG. 4 is a diagram showing an example of the result of measuring the capacitance by the motor control device 1 according to the first embodiment of the present invention. More specifically, FIG. 4 shows the measurement result of the capacitance when the stator of the motor 100 is heated from 40 ° C. to 150 ° C. in a dry state, and the result of FIG. 2 above is shown. It corresponds to.

On the other hand, FIG. 5 is a diagram showing an example of the result of measuring the capacitance by the motor control device 1 according to the first embodiment of the present invention. More specifically, FIG. 5 shows the measurement result of the capacitance when the hygroscopic stator is placed in a high humidity environment and the stator is heated from 40 ° C to 150 ° C. FIG. 3 above. Corresponds to the result of.

As shown in FIG. 4, the capacitance between the winding and the core of the motor 100 in a dry state of the stator of the motor 100 increases as the temperature of the motor 100 rises.

On the other hand, as shown in FIG. 5, in a state where the stator of the motor 100 absorbs moisture, the capacitance between the winding and the core of the motor 100 increases once as the temperature of the motor 100 rises and then decreases. Turn around. Finally, it converges to the same value as the capacitance value shown in FIG.

The change in capacitance shown in FIGS. 4 and 5 represents the change in the relative permittivity of the motor 100. That is, the relative permittivity of the motor 100 is determined by the change due to the temperature of the insulating material and the change due to moisture absorption.

The change in the relative permittivity with temperature can be calculated from the temperature characteristics of the relative permittivity measured in advance. Further, the change in the relative permittivity due to moisture absorption can be calculated from the change in the capacitance of the motor 100 or the change in the insulation resistance.

Next, the difference in the partial discharge start voltage due to the difference in the amount of moisture absorbed by the insulating material will be described with reference to FIG. FIG. 6 is a diagram showing an example of the measurement result of the partial discharge start voltage according to the first embodiment of the present invention. More specifically, FIG. 6 shows the measurement result of the partial discharge start voltage when the moisture-absorbed stator is placed in a high humidity environment and the stator is heated from 40 ° C. to 150 ° C. Here, the amount of moisture absorbed by the insulating material is different between the waveform (a) and the waveform (b), and the amount of moisture absorbed by the waveform (b) is smaller than the amount of moisture absorbed by the waveform (a).

The rate of temperature rise of the motor 100 is the same in the case of FIG. 6 and the case of FIG. The waveform (a) is the same as the waveform shown in FIG. As shown in FIG. 6, the waveform (b) corresponding to the case where the moisture absorption amount of the insulating material is small is compared with the waveform (a) corresponding to the case where the moisture absorption amount of the insulating material is large, and the partial discharge starts in the temperature rise process. It can be seen that the decrease in voltage is small.

Next, a case where the temperature rise rate of the motor 100 is slower than that in the cases of FIGS. 3 and 6 will be described with reference to FIG. 7. FIG. 7 is a diagram showing an example of the measurement result of the partial discharge start voltage according to the first embodiment of the present invention. More specifically, FIG. 7 shows the measurement results of the partial discharge start voltage when the hygroscopic stator is placed in a high humidity environment and the stator is heated from 40 ° C. to 150 ° C.

Here, the waveform (a) in FIG. 7 shows the measurement result of the partial discharge start voltage under the same conditions as the waveform (a) in FIG. On the other hand, the waveform (c) in FIG. 7 shows the measurement result of the partial discharge start voltage when the temperature rise rate is slowed down as compared with the cases of FIGS. 3 and 6. The amount of moisture absorbed is the same for both the waveform (a) and the waveform (c). The waveform of the temperature at which the rising speed is slowed down is also shown in FIG.

As shown in FIG. 7, in the case of the waveform (c) in which the temperature rise rate is slower than that in the waveform (a), the decrease in the partial discharge start voltage in the temperature rise process can be suppressed. This result shows, for example, that the control of suppressing the output of the motor 100 and suppressing the temperature rise of the motor 100 is effective.

As is clear from the results of FIGS. 2 to 7 described above, the partial discharge start voltage can also be controlled by acquiring the relationship of the relative permittivity of the insulating material with respect to the temperature of the motor 100 in advance. Therefore, if the relationship between the temperature and the dielectric constant can be obtained in advance, the calculation of the relative permittivity is executed only when the motor is started, and the partial discharge start voltage is calculated by constantly repeating only the temperature measurement of the motor. It is possible.

The voltage Vsurge applied to the motor 100 described above is not the voltage itself output from the control unit 50, but a voltage including a surge superimposed on the terminals of the motor.

Further, the voltage Vsurge applied to the motor 100 changes depending on the type of cable connecting the motor 100 and the control unit 50, the length of the cable, the rise time of the voltage output from the control unit 50, and the like. Therefore, the voltage Vsurge actually applied to the motor 100 is obtained by measurement or analysis in advance.

As described above, the insulating material is damaged by the partial discharge generated in the insulating portion of the motor 100. As a result, the insulating portion of the motor 100 leads to dielectric breakdown. Therefore, it is important to control the motor so as not to generate a partial discharge. That is, it is necessary to control the motor so that the partial discharge start voltage becomes larger than the voltage applied to the motor 100.

In the first embodiment, it is expressed that the partial discharge occurs in the insulating portion of the motor 100. However, partial discharge also occurs in the wedge-shaped air gap of the insulating paper portion between the winding and the stator, and in the air gap between the winding and the winding. That is, the partial discharge occurs strictly in the air gap. However, in the first embodiment, it is expressed that a partial discharge occurs in the insulating portion of the motor.

Further, in the first embodiment, the case where the motor control is performed for the stator has been described, but the motor control according to the present invention can also be applied to the rotor.

As described above, according to the motor control device according to the first embodiment, it is possible to determine the presence or absence of partial discharge based on the partial discharge start voltage calculated from the temperature of the motor and the relative permittivity of the motor. As a result, in a situation where partial discharge does not occur, it is possible to drive the motor with a high output without performing unnecessary output limitation.

Further, when the occurrence of partial discharge is expected, a configuration is provided in which control for lowering the voltage applied to the motor 100 or control for lowering the output of the motor is executed. As a result, it is possible to suppress a decrease in the partial discharge start voltage in the process of increasing the temperature of the motor. As a result, the effect of making the insulating material of the motor small and thin can be realized.

Embodiment 2.
The configuration and operation of the motor control device 1 according to the second embodiment will be described with reference to FIG.

The configuration of the second embodiment is different from the configuration of the first embodiment in that it includes an insulation life determination unit 60 for preliminarily determining the insulation life of the insulating material of the motor. Therefore, in the description of the second embodiment, the description of the same part as the block diagram shown in FIG. 1 of the first embodiment will be omitted.

FIG. 8 is a block diagram showing the configuration of the motor control device 1 according to the second embodiment of the present invention. The insulation life determination unit 60 is provided between the partial discharge generation determination unit 40 and the control unit 50. The insulation life determination unit 60 counts the number of times the partial discharge generation determination unit 40 determines that a partial discharge has occurred, and controls control information for suppressing the number of times the voltage applied to the motor 100 is switched according to the count number. It is sent to the unit 50.

The insulating material of the motor 100 is damaged by the generation of partial discharge. As a result, the insulating material of the motor 100 leads to dielectric breakdown. The insulation life determination unit 60 generates control information that allows the occurrence of partial discharge within the insulation life based on the preset insulation life.

The insulation life when a partial discharge occurs is determined by the magnitude of the voltage applied to the motor 100 and the number of times the applied voltage is applied. Here, the number of times of voltage corresponds to the number of times that the voltage at which partial discharge occurs is applied to the motor 100.

Therefore, the partial discharge generation determination unit 40 in the second embodiment informs the insulation life determination unit 60 of the magnitude of the voltage at the time of determination and the number of times of application, together with the determination result of whether or not partial discharge occurs. Send out.

On the other hand, the insulation life determination unit 60 in the second embodiment calculates an estimated value of the insulation life when a voltage is applied to the motor 100 based on the magnitude and the number of times of the voltage received from the partial discharge generation determination unit 40. Then, the insulation life determination unit 60 compares the preset insulation life information with the calculated estimated value of the insulation life.

If the estimated value of the insulation life is within the insulation life information, the insulation life determination unit 60 is a first command as a command to maintain the applied voltage or reduce the number of times the applied voltage is applied. Is generated and sent to the control unit 50.

On the other hand, the insulation life determination unit 60 determines that if the estimated value of the insulation life exceeds the insulation life information, dielectric breakdown will occur if the current voltage magnitude and number of times are maintained. A second command is generated and sent to the control unit 50.

When the control unit 50 receives the first command, the control unit 50 performs motor control while maintaining the current magnitude and number of voltages. Alternatively, when the control unit 50 receives the first command, the control unit 50 can suppress damage to the insulation by performing motor control so as to reduce the number of times the command is applied.

When the control unit 50 receives the second command, the control unit 50 executes one or both of the following controls as in the first embodiment.
-Control to reduce the voltage applied to the motor 100.
-Control that lowers the output of the motor 100 and lowers the temperature of the motor 100.

As described above, according to the motor control device according to the second embodiment, by providing the insulation life determination unit, in addition to the effect of the first embodiment, the generation of partial discharge is allowed within the insulation life. It becomes possible to carry out the control. As a result, even in a situation where partial discharge occurs, by allowing the occurrence of partial discharge within the insulation life, it is possible to drive the motor with high output without performing unnecessary output limitation.

Embodiment 3.
The configuration and operation of the motor control device 1 according to the third embodiment will be described with reference to FIG.

The configuration of the third embodiment is different from the configuration of the second embodiment in that the humidity sensor 70 is further provided in order to calculate the moisture absorption amount of the insulating material of the motor from the sensor information. .. Therefore, in the description of the third embodiment, the same part as the block diagram shown in FIG. 8 of the second embodiment will be omitted.

FIG. 9 is a block diagram showing the configuration of the motor control device 1 according to the third embodiment of the present invention. The humidity sensor 70 is provided between the motor 100 and the relative permittivity calculation unit 20. The moisture absorption of the insulating material of the motor is calculated by the relative permittivity calculation unit 20 based on the humidity detection value by the humidity sensor 70.

Specifically, the correspondence relationship for specifying the relative permittivity with the temperature, humidity, and stop time of the motor 100 as parameters is stored in advance in the storage unit as a characteristic table. Therefore, the relative permittivity calculation unit 20 can calculate the relative permittivity by acquiring the temperature, humidity, and the stop period of the motor in the motor and referring to the correspondence stored in the storage unit. it can.

Immediately after the motor 100 is stopped, the temperature of the air inside the motor is high. Then, when the temperature inside the motor begins to drop with the inflow of air from the outside, the humidity changes with the passage of time. That is, the humidity in the motor requires a certain period of time until it becomes stable.

The motor 100 is covered by a frame. The motor 100 is provided with a vent, an outside air introduction port, and the like, and air is exchanged between the inside and the outside of the motor 100.

During the operation of the motor 100, the temperature of the air in the motor rises due to heat generation. On the other hand, when the motor 100 is stopped, the temperature of the air in the motor is lowered, so that the air pressure in the motor is lowered. Then, the outside air flows into the motor.

The temperature and humidity of the external air flowing into the motor are detected by the temperature sensor 10 and the humidity sensor 70, respectively. The detected temperature and humidity information is sent to the relative permittivity calculation unit 20. Therefore, the relative permittivity calculation unit 20 acquires the temperature and humidity inside the motor, and the temperature and humidity outside the motor, acquires the stop period of the motor, and refers to the correspondence stored in the storage unit. , The relative permittivity can also be calculated.

The temperature and humidity outside the motor can also be obtained from the installation position information of the motor 100 and the weather information related to the temperature and humidity.

As described above, according to the motor control device according to the third embodiment, the amount of moisture absorbed by the insulating material of the motor can be obtained more accurately by using the detection results of the temperature sensor and the humidity sensor. As a result, the calculation accuracy of the partial discharge start voltage can be improved, and the control performance for relaxing the output limitation of the motor can be further improved.

Embodiment 4.
The configuration and operation of the motor control device 1 according to the fourth embodiment will be described with reference to FIG.

Compared with the configuration of the first embodiment of the present invention, the configuration of the fourth embodiment uses the atmospheric pressure sensor 80 in order to calculate the partial discharge start voltage including not only the temperature information but also the atmospheric pressure information. Furthermore, it is different in that it has. Therefore, in the description of the fourth embodiment, the description of the same part as the block diagram shown in FIG. 1 of the first embodiment will be omitted.

FIG. 10 is a block diagram showing the configuration of the motor control device 1 according to the fourth embodiment of the present invention. The barometric pressure sensor 80 is provided between the motor 100 and the partial discharge start voltage calculation unit 30. In the fourth embodiment, the partial discharge start voltage of the motor 100 is a partial discharge starting voltage based on the information on the atmospheric pressure detected by the atmospheric pressure sensor 80 together with the information on the temperature and the relative permittivity described in the first embodiment. It is calculated by the discharge start voltage calculation unit 30. The calculated partial discharge start voltage is sent to the partial discharge generation determination unit 40.

Next, a control method for obtaining the partial discharge start voltage by further referring to the information on the atmospheric pressure together with the information on the temperature and the relative permittivity will be specifically described.

It is assumed that the initial partial discharge start voltage is f0 when the initial winding temperature is a0, the initial relative permittivity is b0, and the initial atmospheric pressure is c0. Here, the rate of change of the partial discharge start voltage due to temperature is f1 (a), the rate of change of the partial discharge start voltage due to the relative permittivity is f2 (b), and the rate of change of the partial discharge start voltage due to atmospheric pressure is f3 (c). To do. Under such a premise, the partial discharge start voltage f when the winding temperature is a1, the relative permittivity is b1, and the atmospheric pressure is c1 is expressed by the following equation (2).
f = f0 × f1 (a1) × f2 (b1) × f3 (c1) (2)

The partial discharge start voltage calculation unit 30 calculates the partial discharge start voltage based on the above equation (2). The rate of change f1 (a) of the partial discharge start voltage due to the winding temperature, the rate of change f2 (b) of the partial discharge start voltage due to the dielectric constant, and the rate of change f3 (c) of the partial discharge start voltage due to the atmospheric pressure are It can be acquired by measurement or analysis in advance and stored in a storage unit.

As described above, the motor control device according to the fourth embodiment has a configuration capable of calculating the partial discharge start voltage by further adding the atmospheric pressure information detected by the atmospheric pressure sensor. As a result, the calculation accuracy of the partial discharge start voltage can be improved, and the control performance for relaxing the output limitation of the motor can be further improved. The motor can be driven at high output without unnecessary output limitation of the motor.

Embodiment 5.
The configuration and operation of the motor control device 1 according to the fifth embodiment will be described with reference to FIGS. 11 and 12. In the fifth embodiment, the motor control device mounted on the vehicle will be described as a specific example.

Compared with the configuration of the previous embodiment 4, the configuration of the present embodiment 5 predicts a change in atmospheric pressure due to a change in the external environment, and controls the motor output so as not to decrease the future of the vehicle. The difference is that the position information acquisition unit 90 for acquiring the position information is further provided. Therefore, in the description of the fifth embodiment, the description of the same part as the block diagram shown in FIG. 10 of the fourth embodiment will be omitted.

In the fifth embodiment, it is assumed that the vehicle on which the motor 100 is mounted moves from a low altitude place to a high altitude place in a hygroscopic state. Here, the future position information is the future position information of the vehicle obtained from the car navigation or the like.

FIG. 11 is a block diagram showing the configuration of the motor control device 1 according to the fifth embodiment of the present invention. The partial discharge start voltage calculation unit 30 is acquired by the temperature of the motor 100 detected by the temperature sensor 10, the relative permittivity calculated by the relative permittivity calculation unit 20, the atmospheric pressure detected by the atmospheric pressure sensor 80, and the position information acquisition unit 90. The partial discharge start voltage of the motor 100 is calculated based on the change prediction information of the atmospheric pressure based on the future position information of the vehicle. The calculated partial discharge start voltage is sent to the partial discharge generation determination unit 40.

In the above equation (2), the rate of change f3 (c) of the partial discharge start voltage of the motor due to atmospheric pressure is close to 1 in a place where the altitude is low. As a result, in a place where the altitude is low, the partial discharge generation determination unit 40 determines that the partial discharge does not occur.

On the other hand, in a place where the altitude is high, the rate of change f3 (c) due to the atmospheric pressure of the partial discharge start voltage of the motor becomes a value smaller than 1, and the partial discharge start voltage f calculated by the equation (2) is a place where the altitude is low. It is a small value compared to. Therefore, the partial discharge generation determination unit 40 determines that a partial discharge will occur when the partial discharge start voltage f is equal to or lower than the voltage Vsurge.

Next, specific control of the motor 100 based on the future position information of the vehicle acquired by the position information acquisition unit 90 will be described below. Here, the insulating material of the motor 100 is in a hygroscopic state, has a high relative permittivity, and in a place where the altitude is low, a partial discharge is generated by the partial discharge generation determination unit 40 as described above. It is assumed that it is determined not to be performed.

Here, when the destination of the car is set to a place with a high altitude, the partial discharge start voltage is calculated as a lower value, so that the partial discharge generation determination unit 40 determines that the partial discharge occurs.

Therefore, if it is determined that a partial discharge will occur when the vehicle moves to a high altitude place in the future, the motor control device 1 according to the fifth embodiment will be used in the current place where the altitude is low. , The control to reduce the cooling capacity of the motor is executed within the range where partial discharge does not occur.

For example, the motor control device 1 executes control such as suppressing the cooling of the cooling oil and reducing the capacity of the air-cooling fan, so that the temperature rise of the motor 100 becomes higher as a result. In that case, the partial discharge start voltage will be lower than the original partial discharge start voltage value at the current position.

FIG. 12 is a diagram showing an example of the measurement result of the partial discharge start voltage according to the fifth embodiment of the present invention. More specifically, the waveform (d) shows the measurement result of the partial discharge start voltage in the current place where the altitude is low without reducing the cooling capacity of the motor, and the waveform (e) is The measurement result of the partial discharge start voltage in the state where the cooling capacity of the motor is intentionally lowered in the present place where the altitude is low is shown.

In the waveform (e), the value of the partial discharge start voltage decreases to a smaller value as compared with the waveform (d) as the cooling capacity is reduced. However, in the waveform (e), the time until the partial discharge start voltage rises and stabilizes is shorter than that in the waveform (d).

Therefore, by intentionally lowering the cooling capacity of the motor in the current place where the altitude is low, the value of the partial discharge start voltage can be increased when the motor moves to the place where the altitude is high. As a result, it is not necessary to control the output of the motor 100 when the motor 100 is moved to a place having a high altitude. That is, it is possible to drive the motor 100 with high output in a place where the altitude is high.

As described above, according to the motor control device according to the fifth embodiment, when it is expected to move to a place having a high altitude, the cooling performance is lowered in advance in the current place where the altitude is low. It has a configuration for controlling. As a result, the value of the partial discharge start voltage when moving to a place with a high altitude can be increased. Therefore, when the motor is moved to a place having a high altitude, the motor can be driven with a high output without unnecessary output limitation of the motor.

Next, the processing flow and control method of the motor control device according to the present invention will be specifically described with reference to a flowchart.

First, a specific processing flow of the block diagram of FIG. 1 in the first embodiment will be described with reference to the flowchart of FIG.

FIG. 13 is a flowchart showing a series of processes of the motor control device 1 according to the first embodiment of the present invention. In step S100, the temperature sensor 10 detects the temperature of the winding of the motor.

In step S110, the relative permittivity calculation unit 20 calculates the relative permittivity of the insulating material of the motor. Here, the relative permittivity calculation unit 20 calculates the relative permittivity of the insulating material of the motor based on the temperature detected in step S100.

In step S200, the partial discharge start voltage calculation unit 30 calculates the partial discharge start voltage of the motor 100. The partial discharge start voltage calculation unit 30 uses the above equation (1) to determine the partial discharge start voltage of the motor 100 based on the temperature information received from step S100 and the relative permittivity information received from step S110. calculate.

In step S300, the partial discharge generation determination unit 40 determines whether or not partial discharge of the motor is generated. Specifically, the partial discharge generation determination unit 40 compares the value of the partial discharge start voltage calculated by the partial discharge start voltage calculation unit 30 with the voltage Vsurge applied to the motor, and determines whether or not a partial discharge has occurred. To judge.

As a result of the comparison, if it is determined that the partial discharge does not occur (YES in step S300), the process proceeds to step S400. On the other hand, if it is determined that a partial discharge occurs (NO in step S300), the process proceeds to step S500.

When the process proceeds to step S400, the control unit 50 maintains the current motor control without changing it because the partial discharge does not occur, and ends the series of processes.

On the other hand, when the process proceeds to step S500, the control unit 50 changes the control of the motor to one or more of the following conditions because a partial discharge occurs, and ends the series of processes.
-Control to lower the voltage Vsurge applied to the motor 100.
-Control that lowers the output of the motor 100 and lowers the temperature of the motor 100.

The series of processes from steps S100 to S500 described above are repeated as necessary during the operation of the motor. If the relationship between the temperature and the dielectric constant can be obtained in advance, the calculation of the relative permittivity in step S110 is executed only when the motor is started, and only the temperature measurement of the motor in step S100 is constantly repeated. It is possible to calculate the partial discharge start voltage in step S200.

Next, the flow of processing of the block diagram shown in FIG. 10 in the fourth embodiment will be described with reference to the flowchart of FIG. The motor control device 1 described with reference to FIG. 14 has a different configuration including the atmospheric pressure sensor 80 as compared with the motor control device 1 described with reference to FIG.

Therefore, regarding the processing of each step of the flowchart shown in FIG. 14, the parts common to the flowchart shown in FIG. 13 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 14 is a flowchart showing a series of processes of the motor control device 1 according to the fourth embodiment of the present invention. In step S120, the barometric pressure sensor 80 detects the barometric pressure in the motor.

In step S201, the partial discharge start voltage calculation unit 30 calculates the partial discharge start voltage of the motor 100. The partial discharge start voltage calculation unit 30 uses the above equation (2) based on the temperature information received from step S100, the relative permittivity information received from step S110, and the atmospheric pressure information received from step S120. , Calculate the partial discharge start voltage of the motor 100. Since the processing after step S300 is the same as that in FIG. 13 described above, the description thereof will be omitted.

The motors described in the above embodiments 1 to 5 can be applied to various motors regardless of the type of motor such as a servo motor or an automobile motor, and the motor control device and the motor control method according to the present invention can be applied to various motors. is there.

1 Motor control device, 10 temperature sensor, 20 relative permittivity calculation unit, 30 partial discharge start voltage calculation unit, 40 partial discharge generation determination unit, 50 control unit, 60 insulation life determination unit, 70 humidity sensor, 80 barometric pressure sensor, 90 Future location information of the car, 100 motors.

Claims (12)

A control unit that generates a drive command to the motor,
A temperature sensor that detects the temperature of the winding of the motor and
A relative permittivity calculation unit that calculates the relative permittivity of the insulating material of the motor,
Partial discharge start to calculate the partial discharge start voltage corresponding to the voltage value at which the partial discharge starts in the motor based on the temperature detected by the temperature sensor and the relative permittivity calculated by the relative permittivity calculation unit. Voltage calculation unit and
A portion that compares the applied voltage corresponding to the voltage applied to the motor with the partial discharge start voltage, and determines that partial discharge occurs when the partial discharge start voltage is lower than the applied voltage. Discharge generation determination unit and
With
The control unit
When the partial discharge generation determination unit determines that the partial discharge is generated, at least one of the command for lowering the applied voltage and the command for lowering the output of the motor is generated as the drive command. Control the motor
A motor control device that controls the motor by generating a command for maintaining the applied voltage as the drive command when the partial discharge generation determination unit determines that the partial discharge does not occur. The motor control device according to claim 1, wherein the relative permittivity calculation unit calculates the relative permittivity of the insulating material from the relative permittivity or the insulating resistance of the cooling oil circulating between the electrodes provided in the motor. The relative permittivity calculation unit according to claim 1, wherein the relative permittivity calculation unit calculates the relative permittivity of the insulating material from the relative permittivity or the insulating resistance of the insulating paper or the insulating film arranged between the electrodes provided in the motor. Motor control device. The motor control device according to claim 1, wherein the relative permittivity calculation unit calculates the relative permittivity from the value of the capacitance between the winding of the motor and the core of the motor. Humidity sensor that detects the humidity inside the motor,
With more
The specific dielectric constant calculation unit acquires the external temperature of the motor and the external humidity of the motor in the installation environment of the motor, and obtains the internal temperature of the motor, the internal humidity of the motor, the external temperature of the motor, and the outside of the motor. The motor control device according to claim 1, wherein the amount of moisture absorbed by the insulating material is calculated from the humidity, and the relative dielectric constant of the insulating material is calculated based on the amount of moisture absorbed. Humidity sensor that detects the humidity inside the motor,
With more
The relative permittivity calculation unit stores in advance data in which the temperature of the motor, the humidity of the motor, the stop time of the motor, and the relative permittivity are associated with each other as a characteristic table in the storage unit. The first aspect of claim 1, wherein the relative permittivity of the insulating material is calculated by extracting the temperature detection value, the humidity detection value, and the relative permittivity corresponding to the stop period of the motor from the characteristic table immediately before the motor is stopped. Motor control device. When the applied voltage is equal to or higher than the value of the partial discharge start voltage, the control unit generates a command for suppressing the number of switchings for supplying the applied voltage to the motor as the drive command. The motor control device according to any one of the above items. Further equipped with an atmospheric pressure sensor for detecting the atmospheric pressure in the installation environment of the motor,
The partial discharge start voltage calculation unit starts the partial discharge based on the temperature detected by the temperature sensor, the relative permittivity calculated by the relative permittivity calculation unit, and the pressure detected by the pressure sensor. The motor control device according to any one of claims 1 to 7, wherein the voltage is calculated. The motor is mounted on a car and
Further provided with a position information acquisition unit for acquiring information on the future position of the motor as the vehicle moves.
If the altitude of the future position is higher than the altitude of the current position,
The partial discharge start voltage calculation unit calculates the partial discharge start voltage for each of the current position and the future position.
The partial discharge generation determination unit generates partial discharge for each of the current position and the future position based on the partial discharge start voltage of the current position and the future position calculated by the partial discharge start voltage calculation unit. Determine if it occurs and
When the control unit determines by the partial discharge generation determination unit that partial discharge does not occur at the current position but partial discharge occurs at the future position, the output of the motor is reduced at the current position. The motor control device according to claim 8, wherein a command for increasing the rate of increase in the winding temperature of the motor is generated as the drive command within a range that prevents the motor from being discharged, and the motor is controlled. A motor control method in which a motor is driven and controlled by a motor control device.
In the motor control device
A temperature detection step that detects the temperature of the winding of the motor via a temperature sensor, and
The relative permittivity calculation step for calculating the relative permittivity of the insulating material of the motor, and
A portion that calculates a partial discharge start voltage corresponding to a voltage value at which partial discharge starts in the motor based on the temperature detected by the temperature detection step and the relative permittivity calculated by the relative permittivity calculation step. Discharge start voltage calculation step and
The applied voltage corresponding to the voltage applied to the motor is compared with the partial discharge start voltage, and when the partial discharge start voltage is lower than the applied voltage, it is determined that the partial discharge occurs. Occurrence judgment step and
When it is determined by the partial discharge generation determination step that the partial discharge is generated, at least one of the first drive command for lowering the applied voltage and the second drive command for lowering the output of the motor is issued. A first control step that generates and controls the motor,
A motor control method including a second control step of generating a drive command for maintaining the applied voltage and controlling the motor when it is determined by the partial discharge generation determination step that the partial discharge does not occur. In the first control step, when it is determined by the partial discharge generation determination step that the partial discharge is generated, a drive command for reducing the number of switchings when supplying the applied voltage is issued without lowering the applied voltage. The motor control method according to claim 10, which is generated as the second drive command and controls the motor. It further has an atmospheric pressure detection step of detecting the atmospheric pressure in the installation environment of the motor via an atmospheric pressure sensor.
The partial discharge start voltage calculation step is based on the temperature detected by the temperature detection step, the relative permittivity calculated by the relative permittivity calculation step, and the atmospheric pressure detected by the atmospheric pressure detection step. The motor control method according to claim 10 or 11, wherein the partial discharge start voltage is calculated.

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