WO2018198734A1

WO2018198734A1 - Motor drive device, motor drive method, recording medium, and engine cooling device

Info

Publication number: WO2018198734A1
Application number: PCT/JP2018/014848
Authority: WO
Inventors: 知幸 ▲高▼田
Original assignee: 日本電産株式会社
Priority date: 2017-04-28
Filing date: 2018-04-09
Publication date: 2018-11-01
Also published as: CN110574284B; CN110574284A

Abstract

Provided is a motor drive device for driving a motor, wherein: the motor drive device includes a control unit for outputting a drive signal that causes the motor to be driven, a drive unit for supplying the motor with a current supplied from an external power source on the basis of the drive signal outputted from the control unit, and a current detection unit for detecting the current flowing through the drive unit; and the control unit, after having outputted a drive signal for causing the motor to be driven at a first rotational speed, calculates the torque generated in the motor and the rotational speed of the motor from the current value of the current detected by the current detection unit, compares the calculated value of the calculated torque with a limit value for the torque at the calculated rotational speed, and outputs a drive signal that causes the motor to be driven at a second rotational speed lower than the first rotational speed if the calculated value is higher than the limit value.

Description

Motor driving device, motor driving method, recording medium, and engine cooling device

The present invention relates to a motor drive device, a motor drive method, a recording medium, and an engine cooling device.

The engine cooling device provided in the vehicle cools the engine by circulating and supplying cooling water from the radiator to the engine. The engine cooling device has a cooling fan that sends air to the radiator. The water heated by the engine returns to the radiator, and the heated water is cooled by the wind from the cooling fan.

The motor that drives the cooling fan is controlled by a motor drive device. Electronic components constituting a circuit included in the motor drive device can be damaged by heat generated by driving the motor. The motor drive device has a mechanism that monitors electric power for driving the motor and prevents damage to the electronic components. However, even if the motor is driven with low power, an excessive current may flow through the electronic component, and the electronic component may be damaged.

Patent Document 1 monitors the temperature of an electronic component such as a smoothing capacitor included in a circuit, and restricts the drive current when the temperature of the electronic component exceeds a heat-resistant allowable temperature, thereby preventing damage to the electronic component. A drive device is disclosed.

JP2011-98625A

The load driving device of Patent Document 1 monitors the temperature of the electronic component but does not monitor the current. An electronic component generates heat due to an input current, but a current that may cause damage or deterioration of life may flow to the electronic component in the process of reaching the allowable temperature limit for the electronic component. In this case, the load driving device disclosed in Patent Document 1 may have insufficient protection of electronic components.

An object of the present invention is to provide a motor drive device that is advantageous in terms of safety of operation of electronic components, for example.

An exemplary first invention of the present application is a motor drive device for driving a motor, which is supplied from an external power source based on a control unit that outputs a drive signal for driving the motor and a drive signal output from the control unit. A drive unit that supplies the generated current to the motor, and a current detection unit that detects a current flowing through the drive unit, and the control unit outputs a drive signal for driving the motor at the first rotation speed, Calculate the torque generated in the motor and the rotation speed of the motor from the current value of the current detected by the detection unit, and compare the calculated torque limit value at the calculated rotation speed with the calculated torque value. When the value is higher than the limit value, a drive signal for driving the motor at a second rotational speed lower than the first rotational speed is output.

According to the first exemplary invention of the present application, it is possible to provide a motor drive device that is advantageous in terms of safety of operation of electronic components.

FIG. 1 is a schematic view of an engine cooling device. FIG. 2 is a schematic diagram showing the configuration of the fan system. FIG. 3 is a block diagram showing the configuration of the motor drive device. FIG. 4 is a block diagram illustrating each function of the control unit. FIG. 5 is a flowchart illustrating a process of determining a driving amount in the motor driving method according to the first embodiment. FIG. 6 is a flowchart illustrating a process of determining a drive amount in the motor drive method according to the second embodiment. FIG. 7 is a block diagram showing the configuration of the motor drive device according to the third embodiment. FIG. 8 is a flowchart illustrating a process of determining a drive amount in the motor drive method according to the third embodiment. FIG. 9 is a flowchart showing steps of a motor re-driving method according to the fourth embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.
[First Embodiment]

<Engine cooling device>
FIG. 1 is a schematic diagram of an engine cooling device 1 according to the present embodiment. The engine cooling device 1 includes an engine 10, a water pipe unit 20, a radiator 30, a thermostat 40, a water pump 50, and a fan system 60.

(engine)
The engine 10 includes a water cooling jacket to which cooling water is supplied from the water piping unit 20. The engine 10 is cooled by the cooling water supplied to the water cooling jacket. The heated water after cooling the engine 10 flows out from the cooling jacket to the water piping unit 20.

(Water piping)
The water pipe unit 20 is a pipe for connecting the engine 10 and the radiator 30 to circulate cooling water.

(Radiator)
The radiator 30 is a device that radiates and cools the heat of the heated water by using the wind sent from the fan system 60. The water heated by the engine 10 flows into the radiator 30 through the water piping unit 20 and is cooled, and then flows out from the water piping unit 20 toward the engine 10.

(thermostat)
The thermostat 40 changes the circulation path of the cooling water according to the temperature of the cooling water. When the environmental temperature is high and the engine 10 needs to be cooled, the thermostat 40 opens the pipe on the water pump 50 side when the temperature of the cooling water flowing out of the radiator 30 is lower than the set temperature. When the temperature of the cooling water is equal to or higher than the set temperature, the thermostat 40 does not open the pipe on the water pump 50 side, and allows water to flow to a bypass pipe (not shown). For example, the bypass pipe is connected to the radiator 30, and allows water that is not sufficiently cooled to flow through the radiator 30.

When the environmental temperature is low and the engine 10 needs to be warmed up, the thermostat 40 closes the water pump 50 side pipe and flows cooling water to a bypass pipe (not shown) to the engine 10. Prevent cooling water from flowing in.

(Water pump)
The water pump 50 circulates the cooling water that has passed through the thermostat 40 to the engine 10. The suction port of the water pump 50 is disposed on the thermostat 40 side, and the discharge port is disposed on the engine 10 side.

(Fan system)
The fan system 60 includes a fan blade 61, a motor 62, and a motor driving device 100. The fan blade 61 is rotated by a motor 62 and sends wind toward the radiator 30. In the present embodiment, a three-phase synchronous brushless motor is used as the motor 62, but a motor other than this may be used.

FIG. 2 is a schematic diagram showing the configuration of the fan system 60. Fan blade 61, motor driving device 100 and motor 62 are fixed to shroud 63.

<Motor drive device>
As will be described later, the motor drive device 100 includes a control unit and a drive unit, and has a function of protecting elements included in the drive unit. The element to be protected in the present embodiment is, in particular, a smoothing electrolytic capacitor. The motor driving device 100 is built in a common housing with the motor 62. An output shaft such as a rotor of the motor 62 protrudes from the housing and is attached to the fan blade 61. By making the motor 62 and the motor drive device 100 into a so-called electromechanical integrated type, for example, the fan system 60 can be downsized.

As shown in FIG. 1, the motor driving device 100 is connected to a battery 70 that is an external power source and an engine ECU (Electronic Control Unit) 80. The motor driving device 100 supplies driving current to the motor 62 using electric power obtained from the battery 70. The engine ECU 80 is a control device that controls the engine 10 and is connected to the motor driving device 100 via a communication line. The engine ECU 80 instructs the motor drive device 100 on the number of rotations of the motor 62. Motor drive device 100 transmits a diagnostic message to engine ECU 80. The diagnosis message is transmitted to the engine ECU 80 by the motor drive device 100 when the motor 62 does not rotate despite the command for rotating the motor 62 being output from the engine ECU 80.

Diagnostic message includes, for example, failure information and product information. The failure information is information relating to the type of failure such as a lock failure, a short-circuit failure, and an overheat detection. Product information is information regarding the number of motor outputs, such as 400 W and 600 W, for example.

FIG. 3 is a block diagram showing the configuration of the motor drive device 100. As shown in FIG. As shown in FIG. 3, the motor drive device 100 includes a control unit 110, a drive unit 120, and a current detection unit 130.

(Control part)
Control unit 110 outputs a drive signal to drive unit 120 based on the rotational speed command output from engine ECU 80. As the control unit 110, for example, a computer having an arithmetic processing unit such as a CPU, a memory such as a RAM, and a storage unit such as a hard disk drive is used. However, an electric circuit having an arithmetic device such as a microcontroller may be used instead of the computer. The control unit 110 determines whether to limit the driving of the motor 62 using the current value of the current flowing through the driving unit 120 or the like. Details of the determination method will be described later.

(Drive part)
The drive unit 120 includes an inverter circuit 121, an electrolytic capacitor 122, a field effect transistor 123 for reverse connection protection, and a shunt resistor 124. The drive unit 120 supplies the current supplied from the battery 70 to the motor 62 based on the drive signal output from the control unit 110.

(Inverter circuit)
The inverter circuit 121 is an electric circuit that supplies the current supplied from the battery 70 to the motor 62. Inverter circuit 121 has a pair of switching elements 125 connected in series for each phase of motor 62. As the switching element 125, for example, a transistor such as a field effect transistor is used. In the present embodiment, a metal oxide semiconductor field effect transistor (MOSFET) is used. Electric power for driving the motor 62 is obtained by the switching operation of the switching element 125 based on the drive signal output from the control unit 110. In the present embodiment, the drive signal output from the control unit 110 is a pulse width modulation (PWM) PWM drive signal.

(Electrolytic capacitor)
The electrolytic capacitor 122 is connected in parallel to the element 125A on one side and the element 125B on the other side of the pair of switching elements 125 constituting the inverter circuit 121. The electrolytic capacitor 122 is a smoothing capacitor that suppresses a ripple current according to the switching frequency of the switching element 125.

(Field effect transistor)
The field effect transistor 123 is provided for the purpose of protecting the motor driving device 100 when the battery 70 is reversely connected.

(Current detector)
The current detection unit 130 is an electric circuit for detecting a current flowing through the shunt resistor 124 connected to the inverter circuit 121, that is, a current flowing through the driving unit 120. The current detection unit 130 generates a detection signal indicating a current flowing through the shunt resistor 124 by measuring a potential difference between both ends of the shunt resistor 124. The generated detection signal is sent from the current detection unit 130 to the control unit 110.

(Function of control unit)
FIG. 4 is a block diagram illustrating each function of the control unit 110. The control unit 110 includes a calculation unit 111, a comparison unit 112, a drive amount determination unit 113, and a storage unit 114. In the present embodiment, the control unit 110 monitors the torque generated by the motor 62 and determines whether to limit the driving of the motor 62 based on the monitoring result.

(Calculation unit)
The calculation unit 111 generates the motor 62 from the current value of the current detected by the current detection unit 130 after the drive amount determination unit 113 outputs a drive signal for driving the motor 62 at the first rotation speed to the drive unit 120. The torque and the rotational speed of the motor 62 are calculated. The calculation unit 111 outputs the calculated torque value and the calculated rotation speed to the comparison unit 112. Here, the first rotational speed is the rotational speed of the motor 62 that the engine ECU 80 has commanded to the drive amount determination unit 113. The rotation number calculated by the calculation unit 111 and the first rotation number do not necessarily match.

(Comparison part)
The comparison unit 112 compares the calculated torque value obtained by the calculation unit 111 with the torque limit value, and determines whether or not the calculated torque value is higher than the torque limit value. The comparison unit 112 outputs the determination result to the drive amount determination unit 113.

Further, the comparison unit 112 obtains the first rotational speed from the engine ECU 80. The comparison unit 112 transmits a diagnostic message to the engine ECU 80 when the rotation number obtained by the calculation unit 111 is zero even though the first rotation number is not zero.

The comparison unit 112 refers to the association information stored in the storage unit 114 that associates the rotation number of the motor 62 with the torque limit value, and the torque corresponding to the rotation number obtained by the calculation unit 111 is stored. Determine the limit value. Details of the association information will be described later.

(Driving amount determination unit)
The drive amount determination unit 113 determines the drive amount of the motor 62 based on the command output from the engine ECU 80 or the determination result output from the comparison unit 112. The drive amount determination unit 113 outputs a drive signal corresponding to the determined drive amount to the drive unit 120.

When the determination result output from the comparison unit 112 is a determination result that the calculated value is higher than the limit value, the drive amount determination unit 113 sets the second rotation number that is lower than the first rotation number of the motor 62. Thus, the drive amount for driving the motor 62 is determined as the drive amount for the motor 62. The second rotational speed may be zero. When the calculated torque value is equal to or less than the torque limit value, the drive amount is not particularly limited.

(Storage section)
The storage unit 114 stores in advance association information that associates the rotation speed of the motor 62 with the torque limit value before the motor driving device 100 starts driving the motor 62. The association information is obtained as follows.

(Association information)
First, an allowable ripple current value that is a current value of a ripple current allowed for the electrolytic capacitor 122 to operate stably is calculated. The electrolytic capacitor 122 generates heat due to the input current. When heat is accumulated in the electrolytic capacitor 122 and the temperature rises, the electrolytic capacitor 122 is damaged or the life thereof is deteriorated. Therefore, in order to stably operate the electrolytic capacitor 122, it is important that the current value of the ripple current does not exceed the allowable ripple current value.

The allowable ripple current value is determined by conditions such as the heat generation characteristics of the electrolytic capacitor 122, the environmental temperature in which the electrolytic capacitor 122 is used, and the usage time. The heat generation characteristic of the electrolytic capacitor 122 is determined by the magnitude of an equivalent series resistance (ESR) included in the electrolytic capacitor 122. This is because the electrolytic capacitor 122 generates heat due to the loss of power in the ESR, which is determined by the resistance value of the ESR and the ripple current flowing in the electrolytic capacitor 122. The allowable ripple current value is calculated for each load on the electrolytic capacitor 122. The magnitude of the load includes the number of rotations of the motor 62.

Next, the permissible torque when the current value of the ripple current flowing through the electrolytic capacitor 122 reaches the permissible ripple current value is measured for each rotation speed of the motor 62. A value smaller than the allowable torque is set as a torque limit value. The torque limit value is set for each rotation speed of the motor 62.

¡The allowable torque varies depending on the rotation speed of the motor 62. For example, the amount of increase in the allowable torque with respect to the rotational speed of the motor 62 is small during low-speed to medium-speed rotational driving, and the allowable torque may increase rapidly as the rotational speed of the motor 62 increases during high-speed rotational driving. . Therefore, for example, the torque limit value may be a constant value regardless of the rotation speed of the motor 62, or may increase as the rotation speed of the motor 62 increases.

By the above procedure, association information in which the rotation speed of the motor 62 is associated with the torque limit value is obtained. Since the torque limit value is determined in consideration of the heat generation characteristics of the electrolytic capacitor 122, the torque limit value is set too low when the motor 62 is driven under the condition that the electrolytic capacitor 122 generates a small amount of heat. There is no end. That is, it is possible to prevent excessive drive restriction of the motor 62.

Further, the torque limit value is not excessively increased when the motor 62 is driven under the condition that the ripple current generated by the electrolytic capacitor 122 is large. That is, it is possible to prevent the electrolytic capacitor 122 from being broken and the life deterioration.

Further, since the torque limit value is set for each rotation speed of the motor 62, excessive drive limitation of the motor 62 can be prevented, and the accuracy of the protection control can be improved.

(Driving method)
FIG. 5 is a flowchart illustrating a process of determining a driving amount in the motor driving method according to the first embodiment. In step S 11, the drive amount determination unit 113 determines the drive amount to be output to the drive unit 120 based on the rotational speed command of the motor 62 output from the engine ECU 80. As described above, the rotation speed of the commanded motor 62 output from the engine ECU 80 to the drive amount determination unit 113 is set as the first rotation speed.

In step S12, the calculation unit 111 calculates the torque generated by the motor 62 and the rotation speed of the motor 62 from the current value of the current detected by the current detection unit 130. The calculation unit 111 outputs the calculated torque value and the calculated rotation speed to the comparison unit 112.

In step S 13, the comparison unit 112 determines a torque limit value with reference to the association information stored in the storage unit 114 based on the calculated value of the rotation speed obtained from the calculation unit 111.

In step S14, the comparison unit 112 determines whether or not the calculated torque value calculated in step S12 is higher than the torque limit value determined in step S13. If the comparison unit 112 determines that the calculated value> the limit value, the process proceeds to step S15. If the comparison unit 112 determines that the calculated value ≦ the limit value, the process returns to step S11.

In step S 15, the drive amount determination unit 113 determines a drive amount for restricting the motor 62. Specifically, the drive amount determination unit 113 determines the drive amount for driving the motor 62 at the second rotation number that is lower than the first rotation number as the drive amount of the motor 62.

As described above, by monitoring the current flowing through the motor driving device 100 based on the torque generated in the motor 62, the protection of the elements was insufficient in the power monitoring. For example, the motor 62 is driven at low speed rotation. The elements included in the motor driving device 100 can be protected.
[Second Embodiment]

(Power monitoring)
In the first embodiment, the torque is monitored. In the present embodiment, the power for driving the motor 62 is monitored before the torque is monitored. Thereby, the precision which prevents destruction of the element contained in the drive part 120 can be improved.

(Calculation unit)
The calculation unit 111 is obtained based on the voltage of the battery 70 and the current value of the current detected by the current detection unit 130 after the drive amount determination unit 113 outputs a drive signal for driving the motor 62 at the first rotation speed. The calculated value is calculated as electric power for driving the motor 62. The calculation unit 111 outputs the calculated power value of the power to the comparison unit 112.

(Comparison part)
The comparison unit 112 compares the power value obtained by the calculation unit 111 with the power limit value and determines whether or not the power value is higher than the power limit value. The comparison unit 112 outputs the determination result to the drive amount determination unit 113. The power limit value is determined based on the maximum rating of an element such as a MOSFET and stored in the storage unit 114.

(Driving amount determination unit)
The drive amount determination unit 113 determines the drive amount of the motor 62 based on the determination result output from the comparison unit 112. In the case of the determination result that the power value at the time of driving the motor 62 at the first rotation speed is higher than the power limit value, the drive amount determination unit 113 uses the motor 62 at the second rotation speed that is lower than the first rotation speed. Is determined as the driving amount of the motor 62. The second rotational speed may be zero. When the determination result indicates that the power value is equal to or less than the power limit value, the drive amount determination unit 113 keeps the drive amount as the drive amount for driving the motor 62 at the first rotation speed.

(Driving method)
FIG. 6 is a flowchart illustrating a process of determining a drive amount in the motor drive method according to the second embodiment. Step S11 is the same as in the first embodiment.

In step S22, the calculation unit 111 calculates the power for driving the motor 62 based on the voltage of the battery 70 and the current value of the current detected by the current detection unit 130. The calculation unit 111 outputs the calculated power value to the comparison unit 112.

In step S23, the comparison unit 112 obtains a power limit value from the storage unit 114, and determines whether or not the calculated power value calculated in step S22 is higher than the power limit value. If the comparison unit 112 determines that the calculated value is greater than the limit value, the process proceeds to step S24. When the comparison unit 112 determines that the calculated value ≦ the limit value, the process proceeds to step S12 of the first embodiment.

In step S 24, the drive amount determination unit 113 determines the drive amount for restricting the motor 62. Specifically, the drive amount determination unit 113 determines the drive amount for driving the motor 62 at the second rotation number that is lower than the first rotation number as the drive amount of the motor 62. Step S24 and subsequent steps are the same as steps S12 to S15 of the first embodiment.

As described above, by adding a step of monitoring the power for driving the motor 62 before monitoring the torque, it is possible to improve the accuracy of preventing destruction of the elements included in the drive unit 120.
[Third Embodiment]

In the first embodiment, torque is monitored, and in the second embodiment, power is further monitored before torque is monitored. In this embodiment, the temperature is also monitored after the torque is monitored. Thereby, the precision which prevents destruction of the element contained in the drive part 120 can be improved.

FIG. 7 is a block diagram showing a configuration of the motor drive device 200 according to the present embodiment. As shown in FIG. 7, the motor drive device 200 has a configuration in which a temperature sensor 140 is added to the motor drive device 100 shown in FIG. 3.

(Temperature sensor)
The temperature sensor 140 is a temperature detection unit that detects the temperature of the drive unit 120. In the present embodiment, in particular, the temperature of the electrolytic capacitor 122 is detected. This is because the electrolytic capacitor 122 is easily damaged under the influence of a high current that can flow during low power driving.

(Temperature monitoring)
The control unit 110 monitors the temperature of the drive unit 120 with the temperature sensor 140 and determines whether to limit the drive of the motor 62 based on the monitoring result. By monitoring the temperature of the drive unit 120 together, it is possible to improve the accuracy of control for preventing the elements included in the drive unit 120 from being destroyed.

(Comparison part)
The comparison unit 112 compares the temperature detected by the temperature sensor 140 with a predetermined threshold value, and determines whether or not the detected temperature is higher than the predetermined threshold value. The comparison unit 112 outputs the determination result to the drive amount determination unit 113. The predetermined threshold is an allowable temperature at which an element such as the electrolytic capacitor 122 included in the driving unit 120 operates stably, and is stored in the storage unit 114.

(Driving amount determination unit)
The drive amount determination unit 113 determines the drive amount of the motor 62 based on the determination result output from the comparison unit 112. In the case of a determination result that the temperature detected by the temperature sensor 140 is higher than a predetermined threshold at the time of driving with the rotation speed after monitoring the torque, the drive amount determination unit 113 has a lower rotation speed than the rotation speed after monitoring the torque. Thus, the drive amount for driving the motor 62 is determined as the drive amount for the motor 62. The rotation of the motor 62 may be stopped. In the case of a determination result that the detected temperature is equal to or lower than a predetermined threshold value, the rotation speed after torque monitoring is maintained.

(Driving method)
FIG. 8 is a flowchart illustrating a process of determining a drive amount in the motor drive method according to the third embodiment. Steps S11 to S13 are the same as those in the first embodiment or the second embodiment.

In step S14, the comparison unit 112 determines whether or not the calculated torque value calculated in step S12 is higher than the torque limit value determined in step S13. If the comparison unit 112 determines that the calculated value is greater than the limit value, the process proceeds to step S31 via step S15. If the comparison unit 112 determines that the calculated value ≦ the limit value, the process proceeds to step S31.

In step S31, the comparison unit 112 obtains a predetermined threshold value from the storage unit 114, and determines whether or not the detected temperature detected by the temperature sensor 140 is higher than the predetermined threshold value. If the comparison unit 112 determines that the detected temperature> the predetermined threshold value, the process proceeds to step S32. If the comparison unit 112 determines that the detected temperature ≦ the predetermined threshold value, the process returns to step S11.

In step S 32, the drive amount determination unit 113 determines a drive amount for restricting the motor 62. Specifically, the drive amount determination unit 113 determines a drive amount for driving the motor 62 at a rotational speed lower than the rotational speed after monitoring the torque as the drive amount of the motor 62.

As described above, by adding a step of monitoring the temperature of the drive unit 120 after monitoring the torque, it is possible to improve the accuracy of preventing the elements included in the drive unit 120 from being destroyed.
[Fourth Embodiment]

(Motor re-drive)
As a case where the torque exceeds the limit value, a case where a foreign matter enters the fan system 60 and the foreign matter impedes the rotation of the fan blade 61 may be considered. Then, after the torque exceeds the limit value and the rotational speed of the motor 62 is limited and after a while, the foreign matter that has entered the fan system 60 is discharged to the outside so that the fan blade 61 rotates normally. It can be. In this case as well, driving the motor 62 at a limited number of rotations is an excessive driving limit.

Therefore, in the present embodiment, for example, after a predetermined time has elapsed after starting the limited drive at the second rotational speed, the control unit 110 performs the motor at the third rotational speed that is higher than the second rotational speed. A drive signal for driving the motor 62 is output, and the motor 62 is driven again.

(Re-drive instruction)
The predetermined time until re-driving may be determined in advance. The predetermined time determined in advance is stored in the storage unit 114. For example, the comparison unit 112 can determine whether or not the predetermined time has elapsed. The comparison unit 112 obtains a predetermined time from the storage unit 114, and outputs a determination result to the drive amount determination unit 113 and outputs a signal instructing the drive amount determination unit 113 to re-drive when the predetermined time has elapsed. .

When the drive amount determination unit 113 receives a signal for instructing re-drive from the comparison unit 112, the drive amount for driving the motor 62 at the third rotational speed higher than the rotational speed at which the limit drive is performed is set as the drive amount of the motor 62. decide.

When the motor 62 is driven by the motor driving device 200 having the temperature sensor 140, a time when the temperature of the driving unit 120 is equal to or lower than a predetermined threshold is estimated, and the estimated time may be set as the predetermined time. The predetermined threshold is the same temperature as in the third embodiment, and is stored in the storage unit 114. For example, the comparison unit 112 estimates the time that is equal to or less than the predetermined threshold. The comparison unit 112 obtains a predetermined threshold value from the storage unit 114, obtains a detected temperature from the temperature sensor 140, and estimates a time during which the temperature of the drive unit 120 is equal to or lower than the predetermined threshold value. When the estimated time has elapsed after the comparison unit 112 outputs the determination result to the drive amount determination unit 113. A signal for instructing the drive amount determination unit 113 to re-drive is output.

When the temperature sensor 140 is used for determining the predetermined time, the driving of the motor 62 can be automatically controlled. Further, since the predetermined time is determined based on the actual measured value of the temperature of the drive unit 120, the control accuracy can be improved.

When the temperature sensor 140 is not used, it is not necessary to provide the temperature sensor 140. For example, it can be advantageous in terms of space and cost in the motor driving device 100.

When the motor 62 is driven by the motor driving device 200 having the temperature sensor 140, the motor 62 is not set at the time when the detection result by the temperature sensor 140 is equal to or less than a predetermined threshold value, instead of setting the time until re-driving. May be re-driven. Thereby, the re-driving can be automatically controlled based on the measured value of the temperature of the driving unit 120.

In this case, the re-drive instruction is performed by the comparison unit 112, for example. The comparison unit 112 obtains a predetermined threshold value from the storage unit 114, obtains a detection temperature from the temperature sensor 140, and outputs a signal instructing the drive amount determination unit 113 to re-drive when the detection temperature becomes equal to or less than the predetermined threshold value. Output.

(Re-drive method)
FIG. 9 is a flowchart showing steps of a motor re-driving method according to the fourth embodiment. The re-driving step is performed after step S15 in the first embodiment or the second embodiment. You may perform after process S32 of 3rd Embodiment.

In step S41 following step S15 or step S32, the comparison unit 112 determines whether or not it is time to start redrive as described above. If it is determined that it is time to re-drive, the process returns to step S11, and the drive amount for driving the motor 62 at the third rotational speed higher than the rotational speed that the drive amount determination unit 113 performs the limit drive is driven. Determine as quantity. If it is determined that it is not time for re-driving, the process returns to step S41 with the limited driving.

Providing the motor drive device 100 or the motor drive device 200 according to each of the above embodiments in the engine cooling device 1 improves the stable drive performance of the engine cooling device 1 in which a high current may flow with low power drive. Can do.

Note that a program that causes a computer to execute the driving method described above may be stored in a computer-readable recording medium such as a semiconductor memory, a magnetic disk, or an optical disk, and the recording medium may be accessed by a computer to execute the program. .

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

This application claims priority based on Japanese Patent Application No. 2017-89701, which is a Japanese patent application filed on April 28, 2017, and uses all the contents described in the Japanese Patent Application.

DESCRIPTION OF SYMBOLS 100 Motor drive device 110 Control part 111 Calculation part 112 Comparison part 113 Drive amount determination part 114 Storage part 120 Drive part 130 Current detection part

Claims

A motor driving device for driving a motor,
A control unit for outputting a drive signal for driving the motor;
Based on the drive signal output from the control unit, a drive unit that supplies current supplied from an external power source to the motor;
A current detection unit for detecting a current flowing through the drive unit,
The controller is
After outputting the drive signal for driving the motor at the first rotation speed, the torque generated by the motor and the rotation speed of the motor are calculated from the current value of the current detected by the current detection unit, and calculated. The torque limit value at the rotation speed is compared with the calculated calculated value of the torque, and if the calculated value is higher than the limit value, the second rotation at a rotation speed lower than the first rotation speed Outputting the drive signal for driving the motor in number;
A motor drive device characterized by that.
The motor drive device according to claim 1, wherein the limit value is determined based on a heat generation characteristic with respect to an input current of an element included in the drive unit.
3. The motor driving apparatus according to claim 1, wherein the limit value is a constant value regardless of the number of rotations driven by the motor, or increases as the number of rotations increases.
A temperature detection unit for detecting the temperature of the drive unit;
The controller is configured to drive the motor at the second rotational speed when the temperature detected by the temperature detection unit exceeds a predetermined threshold when the motor is driven at the first rotational speed. The motor driving device according to claim 1, wherein the motor driving device outputs a signal.
When the temperature detected by the temperature detection unit is equal to or lower than the predetermined threshold when the motor is driven at the second rotation number, the control unit performs a third rotation at a higher rotation number than the second rotation number. The motor driving apparatus according to claim 4, wherein the driving signal for driving the motor by a number is output.
The controller drives the motor at a third rotational speed that is higher than the second rotational speed after a predetermined time has elapsed after starting the driving of the motor at the second rotational speed. 5. The motor drive device according to claim 4, wherein a drive signal is output, and the predetermined time is set to a time during which the temperature detected by the temperature detection unit is equal to or less than a predetermined threshold.
The controller drives the motor at a third rotational speed that is higher than the second rotational speed after a predetermined time has elapsed after starting the driving of the motor at the second rotational speed. The motor driving apparatus according to claim 1, wherein a driving signal is output.
When the value obtained based on the voltage of the external power source and the current value exceeds a power limit value when the motor is driven at the first rotation speed, the control unit is configured to rotate the motor at the second rotation speed. The motor driving apparatus according to claim 1, wherein the driving signal for driving the motor is output.
A motor driving method for driving a motor,
Outputting a drive signal for driving the motor at a first rotational speed;
Detecting a current supplied to the motor based on the output drive signal;
Calculate the torque generated in the motor and the rotation speed of the motor from the detected current value of the current,
Comparing the torque limit value at the first rotational speed with the calculated calculated value of the torque;
As a result of the comparison, when the calculated value is higher than the limit value, the drive signal for driving the motor at a second rotational speed lower than the first rotational speed is output.
The motor drive method characterized by the above-mentioned.
A computer-readable recording medium storing a program for causing a computer to execute a motor driving method for driving a motor,
The motor driving method is:
Outputting a drive signal for driving the motor at a predetermined rotational speed;
Detecting a current supplied to the motor based on the output drive signal;
Calculating the torque generated in the motor and the rotational speed of the motor based on the detected current value of the current;
Comparing the torque limit value at the predetermined rotational speed with the calculated calculated value of the torque;
A step of outputting the drive signal for driving the motor at a rotational speed lower than the predetermined rotational speed when the calculated value is higher than the limit value as a result of the comparison;
A computer-readable recording medium.
An engine cooling apparatus comprising a fan driven by a motor controlled by the motor driving apparatus according to claim 1.