JP7501194B2 - Motor Control Device - Google Patents

Description

This disclosure relates to a motor control device.

One example of a motor control device is an air conditioning device for vehicles disclosed in Patent Document 1. This air conditioning device for vehicles controls a blower motor, which is a brush motor. Immediately after the ignition switch changes from the off state to the on state, when a predetermined condition is met, the air conditioning device for vehicles calculates a correction coefficient for correcting the current flow value according to the measured current value at the start of current flow. The air conditioning device for vehicles then compares the corrected current flow value with a reference current value calculated according to the applied voltage value to determine an abnormality in the blower motor.

JP 2008-80928 A

A vehicle air conditioning system can detect abnormalities in the blower motor, which is a brush motor. However, when a brushless motor is used as the blower motor, the vehicle air conditioning system has the problem that it cannot detect abnormalities.

This disclosure has been made in consideration of the above problems, and aims to provide a motor control device that can detect motor abnormalities regardless of the type of motor.

In order to achieve the above object, the present disclosure provides:
A speed acquisition unit (S23) that acquires a rotation speed of the motor;
a decrease determination unit (S25) that determines whether the rotation speed has decreased based on a latest value of the rotation speed obtained in the current acquisition process by the speed acquisition unit and a previous value of the rotation speed obtained in the previous acquisition process;
a storage unit (S26) that stores the latest value used in the determination by the decrease determination unit as a stored value when it is determined that the rotation speed has decreased;
a difference acquisition unit (S29, S30) that acquires a difference between a current value, which is the rotation speed at a time point when a predetermined time has elapsed since the rotation speed was determined to have decreased, and the stored value;
A reduction occurrence determination unit (S20 to S22) that determines whether or not an external factor reduction occurs in which the rotation speed is reduced due to an external factor other than the motor;
The motor control device is provided with an abnormality determination unit (S31, S32) that determines that the motor is abnormal when it is not determined that an external factor decrease has occurred and the difference value reaches the abnormality determination threshold.

In this way, the present disclosure determines that the motor is abnormal when it is not determined that an external factor decrease has occurred and the difference value reaches the abnormality determination threshold. Therefore, the present disclosure can suppress erroneous determination that the motor is abnormal when the rotation speed of the motor decreases due to an external factor other than the motor. Furthermore, the present disclosure determines whether or not the motor is abnormal based on the difference value of the rotation speed. Therefore, the present disclosure can detect motor abnormalities regardless of the type of motor.

The claims and the symbols in parentheses in this section indicate the correspondence with the specific means described in the embodiments below as one aspect, and do not limit the technical scope of this disclosure.

2 is a block diagram showing a schematic configuration of an ECU according to the embodiment; FIG. 4 is a flowchart showing a drive process of an ECU in the embodiment. 4 is a flowchart showing an abnormality determination process of an ECU in the embodiment. 5 is a time chart showing an operation of the ECU in the embodiment when the target rotation speed is constant. 5 is a time chart showing an operation of the ECU in the embodiment when accelerating a target rotation speed.

Below, an embodiment of the present disclosure will be described with reference to Figures 1 to 5. In this embodiment, as an example, a motor control device is applied to an ECU 1 configured to be mountable on a vehicle. ECU is an abbreviation for Electronic Control Unit. In this embodiment, as an example, a motor is applied to a blower motor 2. Note that in Figures 2 and 3, the blower motor 2 is abbreviated to "motor". However, the present disclosure is not limited to this. The motor control device may control a motor different from the blower motor 2.

<Configuration>
1, a description will be given of the configuration of an ECU 1 and the configuration of peripheral devices of the ECU 1. The ECU 1 is electrically connected to a blower motor 2 and a rotation angle sensor 3.

The blower motor 2 is a motor for conditioning the air inside the vehicle cabin. The blower motor 2 is driven to rotate in response to a control signal from the ECU 1. The blower motor 2 rotates an impeller attached to a rotating shaft. The blower motor 2 can be either a brushless motor or a motor with brushes. The rotation angle sensor 3 outputs a rotation pulse signal corresponding to the rotation of the blower motor 2 to the ECU 1.

The ECU 1 is also connected to the battery 4 via the ADC 5. ADC is an abbreviation for analog to digital converter. The voltage from the battery 4 is AD converted by the ADC 5 and then supplied to the ECU 1. This voltage can also be called the power supply voltage. The battery 4 also supplies power to the blower motor 2. The battery corresponds to a power supply.

The ECU 1 is connected to a communication line 8. A higher-level ECU 6 is connected to the communication line 8. The ECU 1 is configured to be able to communicate with the higher-level ECU 6 via the communication line 8. The higher-level ECU 6 is equipped with a CPU, ROM, RAM, etc., just like the ECU 1, which will be described later. The higher-level ECU 6 also has an indicator device 61.

The host ECU 6 determines a target rotation speed for controlling the air volume (rotation speed) of the blower motor 2 based on a temperature signal, etc. The host ECU 6 outputs a command signal (command value) for this target rotation speed. The instruction device 61 is a device operated by the occupant. When the instruction device 61 is operated by the occupant, it outputs, for example, a start signal indicating the start of operation of the blower motor 2 and a stop signal indicating the stop of operation. These signals are transmitted from the host ECU 6 to the ECU 1 via the communication line 8. The start of operation of the blower motor 2 can also be considered as the start of air conditioning. On the other hand, the stop of operation of the blower motor 2 can also be considered as the stop of air conditioning.

The host ECU 6 is also electrically connected to an alarm device 7. The alarm device 7 notifies the driver of an abnormality in the blower motor 2 by outputting alarm information to the vehicle cabin or the like in response to an instruction from the host ECU 6. The host ECU 6 instructs the alarm device 7 to issue an alarm in response to an instruction signal from the ECU 1. The alarm device 7 also outputs alarm information that can be recognized by passengers or the like. Therefore, the alarm device 7 outputs the alarm information by at least one of a sound and a display. For this reason, the alarm device 7 includes a speaker, a display, a warning lamp, or the like.

Note that the present disclosure is not limited to this, and at least one of the indicator device 61 and the alarm device 7 may be directly connected to the ECU 1. Furthermore, the method of notifying an abnormality is not limited to the output of alarm information by the alarm device 7. For example, the ECU 1 stores alarm information that can be read by an external device in the ROM 12. The ECU 1 may then notify an operator of an abnormality when the alarm information is read by the external device. The external device is a device operated by an operator at a dealer, factory, or the like. Furthermore, the ECU 1 may notify an operator at a center of an abnormality by wireless communication using the Internet or the like.

The ECU1 includes a CPU11, a memory device including a ROM12 and a RAM13, and peripheral devices such as a timer14. The ECU1 may also include at least one processor (CPU) and at least one memory device (MMR) as a storage medium for storing programs and data. The ECU1 is provided by a microcomputer having a computer-readable storage medium. The storage medium stores a computer-readable program non-temporarily. The storage medium may be provided by a semiconductor memory or a magnetic disk. The ECU1 may be provided by a computer or a set of computer resources linked by a data communication device. The program is executed by the control device to cause the ECU1 to function as the device described in this specification and to cause the control device to function to perform the method described in this specification. The ECU1 provides various elements. At least some of the elements may be called means for performing a function, and in another respect, at least some of the elements may be called structural blocks or modules.

The means and/or functions provided by ECU1 can be provided by software recorded in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or by a combination of these. For example, when ECU1 is provided by electronic circuits that are hardware, it can be provided by digital circuits including a large number of logic circuits, or by analog circuits.

The ECU 1 is configured to be able to acquire rotation pulse signals, start signals, stop signals, command signals, etc. The ECU 1 operates on the voltage supplied from the battery 4 via the ADC 5. The ECU 1 temporarily stores the value of the supplied voltage (voltage value) in the RAM 13 or the like at predetermined time intervals.

The ECU 1 is configured to be able to output a control signal to the blower motor 2, an instruction signal indicating the output of notification information to the host ECU 6, and the like. The ECU 1 drives and controls the blower motor 2 using PWM control. Furthermore, the ECU 1 drives and controls the blower motor 2 using feedback, for example, using PI control. PWM is an abbreviation for Pulse Width Modulation. PI is an abbreviation for Proportional-Integral Controller.

The CPU 11 executes a program stored in the ROM 12 to perform various calculation processes using acquired signals, etc. The CPU 11 also performs various calculation processes while temporarily storing the calculation results in the RAM 13.

For example, the CPU 11 calculates the rotation speed of the blower motor 2 at predetermined time intervals based on the rotation pulse signal from the rotation angle sensor 3, and temporarily stores the calculated rotation speed in the RAM 13 or the like. The CPU 11 outputs a control signal corresponding to a command signal for the target rotation speed to the blower motor 2. Furthermore, the CPU 11 determines whether the voltage of the battery 4 has decreased based on the power value supplied via the ADC 5. The processing operation of the ECU 1 (CPU 11) will be described in detail later.

The timer 14 starts counting time in response to an instruction from, for example, the CPU 11. The CPU 11 is configured to be able to refer to the elapsed time measured by the timer 14. The CPU 11 compares the elapsed time with the mask time mt to determine whether the elapsed time has reached the mask time mt. The mask time mt is stored, for example, in the ROM 12. The mask time mt is a time during which a comparison is not made between the difference value and a threshold value, which will be described later. The mask time mt will be described in more detail later.

The CPU 11 may be configured to be able to refer to the vehicle speed, the open/closed state of the vehicle interior windows, and the like. The vehicle speed is input to the ECU 1 from the host ECU 6 or a vehicle speed sensor. The open/closed state is the position of the window between the fully closed position and the fully open position. A position signal indicating the window position is input to the ECU 1 from the host ECU 6 or the like. This allows the CPU 11 to acquire the open/closed state. The CPU 11 also estimates the change in air pressure inside the vehicle interior from the vehicle speed and the open/closed state of the window. For example, if the CPU 11 determines that the vehicle is traveling at high speed and exceeds a predetermined value, and that the window is fully open, it estimates that the air pressure inside the vehicle interior is high.

<Processing Operation>
Here, the processing operation of the ECU 1 will be described with reference to Figures 2 to 5. When the ECU 1 receives a start signal, it starts the flow charts of Figures 2 and 3. First, the drive processing of Figure 2 will be described. Note that Figures 2 and 3 are mainly processes performed by the CPU 11.

In step S10, the rotation speed is acquired. The CPU 11 calculates the rotation speed of the blower motor 2 based on the rotation pulse signal. In other words, the CPU 11 acquires the rotation speed by calculating the rotation speed. The calculated rotation speed is the actual rotation speed, and therefore can also be called the actual rotation speed.

In step S11, it is determined whether or not a fail-safe is necessary. The CPU 11 determines whether or not a fail-safe is necessary. The fail-safe is a function that protects the blower motor 2 by slowing down the rotational speed of the blower motor 2. The CPU 11 determines whether or not a fail-safe is necessary depending on whether or not an abnormality that requires a fail-safe has occurred in the blower motor 2. If the CPU 11 determines that a fail-safe is necessary, it proceeds to step S12, and if it does not determine that a fail-safe is necessary, it proceeds to step S13. If the CPU 11 determines that a fail-safe is necessary, it temporarily stores fail information indicating that a fail-safe is occurring.

In step S12, deceleration control is performed. The CPU 11 changes the target rotation speed in order to perform deceleration control of the blower motor 2. In other words, the CPU 11 changes the target rotation speed indicated by the command signal received from the host ECU 6.

In step S13, a control instruction is issued. The CPU 11 outputs a control signal in accordance with the target rotation speed changed in step S12. The CPU 11 then outputs the control signal to the blower motor 2 to drive and control the blower motor 2.

In step S14, it is determined whether or not the motor is to be stopped. The CPU 11 determines whether or not to stop the blower motor 2 based on whether or not a stop signal has been received. If the CPU 11 has received a stop signal, it determines to stop the blower motor 2 and ends the flowchart in FIG. 2. If the CPU 11 has not received a stop signal, it returns to step S10 without determining to stop the blower motor 2.

Next, the abnormality determination process in FIG. 3 will be described. The CPU 11 determines whether or not an externally-caused decrease has occurred by performing steps S20 to S22 (decrease occurrence determination section). An externally-caused decrease is a decrease in the rotation speed of the blower motor 2 due to an external factor other than the blower motor 2. It can also be said that the CPU 11 performs steps S20 to S22 to detect an abnormality in the blower motor 2 only in a situation where there is no possibility of an externally-caused decrease occurring. Thus, the CPU 11 determines whether or not a decrease in the rotation speed of the blower motor 2 is due to an abnormality in the blower motor 2 itself.

An abnormality in the blower motor 2 is a breakdown or deterioration of the blower motor 2. An abnormality in the blower motor 2 can be, for example, a break in the windings of the blower motor 2. As will be explained later, the CPU 11 detects an abnormality from the difference value ds in the rotation speeds, and is therefore able to detect an abnormality before the blower motor 2 stops operating. Therefore, an abnormality in the blower motor 2 can be said to be a sign of an impending breakdown in the blower motor 2.

In step S20, it is determined whether the speed is constant or accelerating (decrease occurrence determination section). The CPU 11 determines whether the blower motor 2 is being driven and controlled so that the rotation speed is constant, or whether the blower motor 2 is being driven and controlled so that the rotation speed is accelerated. In other words, the CPU 11 determines whether the blower motor 2 is being driven and controlled so that the rotation speed is decelerated. In other words, the CPU 11 determines whether the blower motor 2 is being decelerated. It can also be said that the CPU 11 determines whether the target rotation speed is one at which the rotation speed needs to be decelerated to drive and control the blower motor 2.

During deceleration control, a decrease in rotation speed may occur even if no abnormality occurs in the blower motor 2. For this reason, the CPU 11 does not perform abnormality determination using the difference value ds when deceleration control is in progress.

If the CPU 11 determines that the vehicle is moving at a constant speed or accelerating, i.e., that deceleration control is not being performed, the CPU 11 proceeds to step S21. If the CPU 11 does not determine that the vehicle is moving at a constant speed or accelerating, it assumes that an external factor degradation has occurred and proceeds to step S34. For example, if the latest value is greater than or equal to the previous value, the CPU 11 determines that the vehicle is moving at a constant speed or accelerating. If the latest value is less than the previous value, the CPU 11 does not determine that the vehicle is moving at a constant speed or accelerating.

The CPU 11 may also determine whether the rotation speed is constant or accelerating based on the latest value of the rotation speed and the target rotation speed. In this case, if the latest value is less than or equal to the target rotation speed, the CPU 11 determines that the rotation speed is constant or accelerating. If the latest value is greater than the target rotation speed, the CPU 11 does not determine that the rotation speed is constant or accelerating, that is, determines that deceleration control is in progress.

In step S21, it is determined whether or not the fail-safe has occurred (decrease occurrence determination unit). When the fail-safe is occurring, a decrease in the rotation speed may occur even if no abnormality has occurred in the blower motor 2. For this reason, when the fail-safe is occurring, the CPU 11 does not perform an abnormality determination using the difference value ds.

If no fail information is stored, the CPU 11 determines that a fail-safe has not occurred and proceeds to step S22. If fail information is stored, the CPU 11 does not determine that a fail-safe has not occurred, assumes that an external factor degradation has occurred, and proceeds to step S34.

In step S22, it is determined whether the voltage is constant (decrease occurrence determination unit). If the voltage supplied from the battery 4 is not constant, a decrease in the rotation speed may occur even if no abnormality has occurred in the blower motor 2. For this reason, if the voltage is not constant, the CPU 11 does not perform an abnormality determination using the difference value ds.

If the CPU 11 determines that the voltage is constant, it proceeds to step S23. If the CPU 11 does not determine that the voltage is constant, it assumes that a drop due to an external factor has occurred and proceeds to step S34.

The voltage supplied from the battery 4 may normally fluctuate within a specified range. However, even if the voltage fluctuates within the specified range, this does not affect the drive control of the blower motor 2. Therefore, the CPU 11 determines that the voltage is constant when the voltage is within the specified range, and does not determine that the voltage is constant when the voltage is not within the specified range.

If the CPU 11 judges YES in step S22, it executes the process from step S23 onwards. In other words, the CPU 11 executes the process from step S23 onwards only when no external factor degradation occurs.

In this embodiment, an example is adopted in which all of steps S20 to S22 are performed. However, the present disclosure can also be adopted in which at least one of steps S20 to S22 is performed.

In step S23, the rotation speed is acquired (speed acquisition section). The CPU 11 acquires (calculates) the rotation speed of the blower motor 2 from the rotation pulse signal. This rotation speed is the latest value at this point in time.

In step S24, the rotation speed is stored. The CPU 11 temporarily stores the rotation speed obtained in step S23 in the RAM 13.

In step S25, it is determined whether the rotation speed has decreased (decrease determination unit). The CPU 11 determines whether the rotation speed has decreased based on the previous value and the latest value of the rotation speed stored in the RAM 13. If the CPU 11 determines that the rotation speed has decreased, the process proceeds to step S26, and if the CPU 11 does not determine that the rotation speed has decreased, the process proceeds to step S34. In Figures 4 and 5, it is assumed that an abnormality occurs at timing t1, causing the rotation speed to decrease.

In step S26, the rotation speed is stored as a stored value (storage unit). The CPU 11 stores the rotation speed at the time when it is determined that the rotation speed has decreased as a stored value. This is to calculate the difference value ds of the rotation speed.

In step S27, the timer is started (difference acquisition unit). The CPU 11 starts measuring the elapsed time using the timer 14. The CPU 11 uses the timer 14 to measure the elapsed time from the point in time when it is determined that the rotation speed has decreased.

In step S28, it is determined whether the mask time has elapsed (difference acquisition unit). The CPU 11 determines whether the mask time mt has elapsed since the start of disclosure in step S27. That is, the CPU 11 compares the elapsed time with the mask time mt, and if the elapsed time reaches the mask time mt, it determines that the mask time mt has elapsed and proceeds to step S29. The CPU 11 compares the elapsed time with the mask time mt, and if the elapsed time does not reach the mask time mt, it does not determine that the mask time mt has elapsed and repeats step S28.

The mask time mt corresponds to a predetermined time. In this embodiment, as an example, a time that correlates with the atmospheric pressure and rotation speed of the atmosphere in which the blower motor 2 is located is used as the mask time mt. When the atmospheric pressure in the atmosphere in which the blower motor 2 is located (such as the interior of the vehicle) increases, the rotation speed of the blower motor 2 may temporarily decrease and then return to the original speed. In addition, the atmospheric pressure increases when the vehicle is traveling at a relatively high speed and the vehicle windows are open. Furthermore, the atmospheric pressure may increase when the rotation speed decreases.

The CPU 11 therefore performs steps S27 and S28 to avoid making an abnormality determination in a situation where the rotation speed is reduced by air pressure. In other words, the CPU 11 performs steps S27 and S28 to mask the execution of an abnormality determination for a predetermined time after the rotation speed has decreased. Abnormality determination will be explained later.

The mask time mt can be a predetermined fixed time. In this case, the mask time mt can be a time estimated by an experiment or a simulation, which is the time from when the rotation speed temporarily decreases due to the high pressure until it returns to normal.

The mask time mt may also be variable depending on the vehicle speed and the open/closed state of the window. In this case, for example, a map in which the vehicle speed, the open/closed state, and the mask time mt are associated is stored in the ROM 12. The map can be created by varying the vehicle speed and the open/closed state, and estimating or measuring the time it takes for the rotation speed to temporarily decrease and return to normal each time. The CPU 11 then refers to the map and determines the mask time mt from the acquired vehicle speed and open/closed state.

The CPU 11 may execute steps S27 and S28 when it estimates that the air pressure inside the vehicle cabin is high as described above. In addition, the mask time mt (predetermined time) does not have to be a time that correlates with the air pressure and rotation speed of the atmosphere in which the blower motor 2 is located.

In step S29, the rotation speed is acquired. As in step S23, the CPU 11 acquires the rotation speed of the blower motor 2 as the current value. This is to calculate the difference value ds between the stored value and the current value.

In step S30, a difference value ds between the current value and the saved value is calculated (difference acquisition unit). The CPU 11 acquires the difference value ds between the current value, which is the rotation speed at the time when the mask time mt has elapsed since it was determined that the rotation speed had decreased, and the saved value saved in step S26. This is to use the difference value ds to determine whether there is an abnormality in the blower motor 2. The difference value ds is the difference in the decrease in rotation speed.

In step S31, it is determined whether the difference value ds is equal to or greater than the threshold value. If the CPU 11 determines that the difference value ds has reached the threshold value, it assumes that an abnormality has occurred in the blower motor 2 and proceeds to step S32. If the CPU 11 does not determine that the difference value ds has reached the threshold value, it assumes that no abnormality has occurred in the blower motor 2 and proceeds to step S34.

The threshold value may be, for example, a value indicating a tolerance range. Therefore, it can be said that the CPU 11 determines whether or not the difference value ds is within the tolerance range. If the CPU 11 does not determine that the difference value ds is within the tolerance range, the process proceeds to step S32. If the CPU 11 determines that the difference value ds is within the tolerance range, the process proceeds to step S34. The tolerance here refers to a range value within which the performance of the blower motor 2 fluctuates from the target rotation speed. The threshold value corresponds to an abnormality determination threshold.

As shown in Figures 4 and 5, the CPU 11 does not calculate the difference value ds until the mask time mt has elapsed since the decrease in rotation speed. In other words, the CPU 11 does not perform an abnormality determination.

In step S32, an abnormality is determined (abnormality determination section). If it is determined that no external factor degradation has occurred and the difference value ds has reached the threshold value, the CPU 11 determines that the blower motor 2 is abnormal.

The CPU 11 can perform an abnormality determination even when the target rotation speed is a constant speed as shown in FIG. 4, or when the target rotation speed indicates acceleration as shown in FIG. 5. The upper parts of FIG. 4 and FIG. 5 show a state in which the actual rotation speed does not reach the target rotation speed even when the duty is 100%. The middle parts of FIG. 4 and FIG. 5 show a state in which the actual rotation speed does not reach the target rotation speed even when the duty is changed from 80% to 100%. The lower parts of FIG. 4 and FIG. 5 show a state in which the actual rotation speed does not reach the target rotation speed even when the duty is changed from 60% to 80%. Note that the duty used here is just an example.

In step S33, the abnormality is notified (notification unit). If the CPU 11 determines in step S32 that the blower motor 2 is abnormal, the CPU 11 notifies the abnormality of the blower motor 2. The CPU 11 outputs an instruction signal to the host ECU 6, thereby notifying the abnormality from the notification device 7.

The ECU 1 can inform the vehicle owner or an operator such as a dealer of the abnormality, thereby informing them of the timing to replace the blower motor 2. Thus, the ECU 1 can replace the blower motor 2 before it breaks down. As a result, the ECU 1 can prevent situations in which heating and cooling cannot be used, or the defroster cannot be used in bad weather. However, the present disclosure does not necessarily require the abnormality to be notified.

In step S34, it is determined whether the motor is stopped. The CPU 11 determines whether the motor is stopped, similarly to step S14. The CPU 11 determines that the blower motor 2 is to be stopped, and ends the flowchart of FIG. 3. If the CPU 11 determines that the blower motor 2 is not to be stopped, it returns to step S20.

＜Effects＞
In this way, the ECU 1 determines that the blower motor 2 is abnormal when it is not determined that an external factor decrease has occurred and the difference value ds reaches the threshold value. This makes it possible for the ECU 1 to suppress erroneous determination that the blower motor 2 is abnormal when the rotation speed of the blower motor 2 decreases due to an external factor other than the blower motor 2. The ECU 1 also determines whether the blower motor 2 is abnormal based on the rotation speed difference value ds. Therefore, the ECU 1 can detect an abnormality in the blower motor 2 regardless of the type of the blower motor 2.

If the ECU 1 does not determine that the speed is constant or that the motor is accelerating, it assumes that an external factor has caused a decrease and does not perform an abnormality determination. This allows the ECU 1 to at least suppress determining that a decrease in rotation speed due to deceleration control is an abnormality in the blower motor 2.

If the ECU 1 does not determine that the fail-safe has not yet occurred, it assumes that an external factor decrease has occurred and does not perform an abnormality determination. This allows the ECU 1 to at least suppress the determination that a decrease in rotation speed due to the fail-safe is an abnormality in the blower motor 2.

When the ECU 1 determines that the voltage supplied from the battery 4 is not constant, it assumes that an external factor has caused the voltage drop and does not determine that there is an abnormality. This allows the ECU 1 to at least suppress determining that a drop in rotation speed due to an inconsistent voltage is an abnormality in the blower motor 2.

In particular, if the ECU 1 does not determine that the speed is constant or that the vehicle is accelerating, does not determine that the fail-safe has occurred, and determines that the voltage supplied from the battery 4 is not constant, it assumes that an external factor has caused a drop in the speed and does not perform an abnormality determination. This makes it possible for the ECU 1 to more reliably prevent erroneous determination that the blower motor 2 is abnormal when the rotation speed of the blower motor 2 drops due to an external factor other than the blower motor 2.

The above describes a preferred embodiment of the present disclosure. However, the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

Although the present disclosure has been described with reference to an embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, while various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less are also within the scope and concept of the present disclosure.

1...ECU, 11...CPU, 12...ROM, 13...RAM, 14...timer, 2...blower motor, 3...rotation angle sensor, 4...battery, 5...ADC, 6...host ECU, 61...indicator, 7...alarm device, 8...communication line,

Claims (6)

A speed acquisition unit (S23) that acquires a rotation speed of the motor;
a decrease determination unit (S25) that determines whether the rotation speed has decreased based on a latest value of the rotation speed acquired in a current acquisition process by the speed acquisition unit and a previous value of the rotation speed acquired in a previous acquisition process;
a storage unit (S26) configured to store, when it is determined that the rotation speed has decreased, the latest value used in the determination by the decrease determination unit as a stored value;
a difference acquisition unit (S29, S30) that acquires a difference between a current value, which is the rotation speed at a time point when a predetermined time has elapsed since the time point when it is determined that the rotation speed has decreased, and the stored value;
A reduction occurrence determination unit (S20 to S22) that determines whether or not an external factor reduction occurs in which the rotation speed is reduced due to an external factor other than the motor;
and an abnormality determination unit (S31, S32) that determines that the motor is abnormal when it is determined that the external factor decrease has not occurred and the difference value reaches an abnormality determination threshold. The motor control device according to claim 1, wherein the degradation occurrence determination unit determines whether deceleration control is being performed so as to bring the rotation speed closer to a target rotation speed, and when it is determined that deceleration control is being performed, determines that the external factor degradation has occurred. The motor control device according to claim 1 or 2, wherein the decrease occurrence determination unit determines whether a fail-safe that decelerates the rotation speed is occurring, and if it is determined that the fail-safe is occurring, determines that the decrease due to an external factor will occur. It operates by receiving voltage from a power source.
The motor control device according to any one of claims 1 to 3, wherein the decrease occurrence determination unit determines whether the voltage is within a predetermined range, and if it determines that the voltage is not within the predetermined range, determines that the decrease due to an external factor has occurred. the motor is a blower motor for conditioning air in a vehicle cabin,
5. The motor control device according to claim 1, wherein the predetermined time period is a time period that correlates with the atmospheric pressure of an atmosphere in which the blower motor is located and the rotational speed. The motor control device according to any one of claims 1 to 5, further comprising a notification unit (S33) that notifies the motor of an abnormality when the abnormality determination unit determines that the motor is abnormal.