JP2004096888A - Rotor breakage detection system - Google Patents

Abstract

A means for detecting rotor damage is provided.
A rotational speed of a motor is acquired (S10), an error from a rotational speed command value is calculated (S20), and when the number of times the error exceeds a predetermined value is equal to or more than a predetermined number, the rotation of the motor is started. The number is determined to be abnormal. Further, after the stator temperature is obtained (S70) and the stator temperature is corrected in a predetermined manner (S80), if the stator temperature correction value is higher than the allowable temperature, it is determined that the stator temperature is abnormal. If it is determined that the rotation speed of the motor and the stator temperature are abnormal, it is detected that the rotor is damaged, and a warning lamp is turned on (S110) and the driving of the motor is restricted (S120).
[Selection diagram] Fig. 4

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for detecting an abnormality of a motor for a vehicle. In particular, the present invention relates to a rotor damage detection system that detects damage to a rotor that constitutes a motor.
[0002]
[Prior art]
A hybrid vehicle using an engine and a motor as a driving force source is known. The number of rotations of the motor of the hybrid vehicle fluctuates due to vehicle speed up and down and vehicle control during actual running. At this time, repetitive stress is generated in the rotor due to centrifugal force, and the rotor may be damaged by fatigue.
[0003]
[Problems to be solved by the invention]
However, a conventional hybrid vehicle does not include a means for detecting rotor damage, and if the rotor damage progresses in an actual vehicle, the hybrid vehicle may eventually become unable to run on its own.
[0004]
Generally, since the rotor is made of laminated steel plates, the damage progresses one by one, but as the damage progresses, the damage range exponentially expands. The effect of this phenomenon on the behavior of the vehicle is that if a few sheets in the early stage of the damage are damaged, the output decreases little and the vehicle can run on its own. Therefore, it is important to detect the rotor damage at the beginning of the damage start and stop the progress of the damage in order to ensure the safety of the driver.
[0005]
Therefore, an object of the present invention is to provide a rotor damage detection system that can solve the above-described problems.
[0006]
[Means for Solving the Problems]
To help understand the present invention, a description will be given of rotor damage. FIG. 1 is a diagram showing a main configuration of a motor for driving a vehicle. In this figure, 1/4 of the rotor and the stator are shown. The rotor is formed by laminating a plurality of electromagnetic steel sheets, and two holes 312 are formed in a rotor piece 310 corresponding to １ ／ of the rotor. The permanent magnet 314 is inserted into each of the two holes 312. At both ends of each permanent magnet 314, the distance from the outer periphery of the rotor to the permanent magnet 314 is small, and the distance 313 in the figure is typically about 1 mm.
[0007]
The stator piece 320, which corresponds to １ ／ of the stator, is arranged around the rotor piece 310 via a minute gap 322. Usually, this gap is about 0.5 mm. Stator piece 320 is provided with three holes 324. A stator coil (not shown) is inserted and arranged in the hole 324.
[0008]
A rotating shaft is arranged at the center of the rotor and fixed to the rotor. Also, four stator pieces 320 are connected in the circumferential direction to form a stator. The stator produces a rotating magnetic field. Since the permanent magnet 314 is disposed in the rotor, a rotating torque is generated in the rotor by the rotating magnetic field, and the rotor is rotated.
[0009]
In the motor configured as described above, the rotor may be broken at both ends of the permanent magnet 314 due to repeated stress due to centrifugal force. When the rotor is damaged, the rotor and the stator are partially in contact with each other, and the rotational speed of the motor is reduced due to friction.
[0010]
When the ECU that controls the motor detects a decrease in the rotation speed of the motor, the ECU that increases the current flowing through the stator coil attempts to maintain the predetermined rotation speed. As a result, the rotation speed of the motor returns to a normal state once. However, when the damage of the rotor progresses, the reduction of the rotation speed of the motor and the maintenance of the rotation speed by the ECU are repeated again.
[0011]
FIG. 2 is a graph showing the behavior of the motor rotation speed and the transition of the stator temperature at the initial stage of rotor damage. In FIG. 2, t0 indicates the time at which the motor starts, and t1, t2, and t3 indicate the times at which the rotor and the stator partially contact each other. After starting the motor, the stator temperature increases as the total amount of current flowing through the stator coil increases. At time t1, when partial contact occurs, the motor rotation speed falls below a predetermined command value. On the other hand, the stator temperature becomes higher than the normal stator temperature due to frictional heat between the rotor and the stator. After time t1, the motor speed returns to the command value by the current control by the ECU. Thereafter, when the damaged portion of the rotor expands and partial contact occurs again at times t2 and t3, the difference between the actual stator temperature and the normal temperature gradually increases.
[0012]
As described above, in the initial stage of rotor damage, each time the rotor and the stator come into partial contact, the rotation speed of the motor decreases and the temperature of the stator gradually increases as compared with the normal state.
[0013]
Therefore, a desirable mode of the present invention is a rotor damage detection device that detects damage to a rotor that constitutes a motor for driving a vehicle, the motor rotation state detection means detecting a motor rotation state, and a stator detecting a stator temperature. Temperature detection means, a motor rotation abnormality determination unit that determines whether the motor rotation state is a predetermined motor rotation abnormality state, and a stator temperature abnormality that determines whether the stator temperature is a predetermined abnormality temperature A determination unit, wherein when the motor rotation state is a predetermined motor rotation abnormal state and the stator temperature is a predetermined abnormal temperature, it is determined that the rotor is damaged.
[0014]
Another preferred embodiment of the present invention is a rotor damage detection device for detecting damage to a rotor constituting a motor, the motor rotation speed detection means for detecting a motor rotation speed, and a stator temperature detection device for detecting a stator temperature. A motor rotation abnormality determining unit that determines that the motor rotation is abnormal when a state in which the motor rotation speed has decreased by a predetermined value or more from a set value of the motor rotation speed occurs a predetermined number of times; A stator temperature abnormality determining unit that determines that the stator temperature is abnormal when the stator temperature is higher than a specified temperature set in accordance with the amount, and determines that the motor rotation state is a motor rotation abnormality state. And when it is determined that the stator temperature is abnormal, it is determined that the rotor is damaged.
[0015]
Still another preferred embodiment of the present invention is a rotor damage detection device for detecting damage to a rotor constituting a motor, comprising: a motor rotation speed detection means for detecting a motor rotation speed; and a stator temperature for detecting a stator temperature. A detecting unit, a stator temperature correcting unit that corrects the stator temperature based on the operating condition of the motor, and a state in which the motor rotation speed has decreased by a predetermined value or more from a set value of the motor rotation speed for a predetermined number of times. A motor rotation abnormality determination unit that determines that the motor is in an abnormal rotation state, and when the stator temperature correction value is higher than a specified temperature set according to the amount of current flowing to the motor, the stator temperature is an abnormal temperature. A stator temperature abnormality determination unit that determines that there is a motor rotation state, wherein the motor rotation state is determined to be a motor rotation abnormality state, If the degree is determined to be abnormal temperature, it is determined that the rotor is damaged.
[0016]
According to the configuration described above, by detecting an abnormality in the rotation state of the rotor and an abnormality in the stator temperature, it is possible to reliably detect damage to the rotor at an initial stage.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are solutions of the invention. It is not always necessary for the means.
[0018]
FIG. 3 is a schematic configuration diagram of the rotor damage detection system 2 according to the embodiment. In the rotor damage detection system 2, a three-phase AC motor is used as the motor 10 for running the vehicle. The drive current of the motor 10 is supplied from a battery 14 via an inverter 12. The inverter 12 is provided corresponding to the U, V, and W phase windings of the motor 10 and exchanges the switching elements Q1 to Q6 connected in a three-phase bridge with each other to exchange the discharge output of the battery 14 with three-phase AC. Have. As the switching elements Q1 to Q6, for example, large power transistors such as IGBTs can be used. The inverter 12 further includes a capacitor C for smoothing the output voltage of the battery 14 and a discharge resistance R of the capacitor C.
[0019]
The operation of inverter 12, in particular, switching elements Q <b> 1 to Q <b> 6 are controlled by EV-ECU 16. The EV-ECU 16 turns on the relay unit 20 in response to, for example, operation of an ignition switch, and connects the battery 14 and the inverter 12. The EV-ECU 16 inputs an accelerator signal indicating the amount of depression of the accelerator pedal by the user, a brake signal indicating the amount of depression of the brake pedal by the user, a shift position signal indicating the shift position applied by the user, and the like. A rotation speed command value for the motor 10, that is, a value of a rotation speed at which the motor 10 should rotate is calculated. The EV-ECU 16 converts the rotation speed command value thus obtained into a current command value.
[0020]
The EV-ECU 16 receives feedback of the detection values of the phase currents Iu, Iv, Iw of the motor 10 from the inverter 12, and receives the rotation speed of the motor 10 from a rotor position sensor 18 such as a resolver attached to the motor 10. That is, a change in the position of the rotor of the motor 10) is input. The EV-ECU 16 compares the detected values of the phase currents Iu, Iv, Iw with the current control values, and uses the current control error (deviation) obtained as a result and the rotation speed of the motor 10 to calculate each phase current. A control target of Iu, Iv, Iw or a control target of each phase voltage Vu, Vv, Vw is determined. That is, when the rotation speed of the motor 10 decreases due to the partial contact between the rotor and the stator, the phase currents Iu, Iv, Iw are increased so that the motor 10 generates a torque to be output, and the rotation speed is reduced. Try to keep.
[0021]
The EV-ECU 16 generates a pulse width modulation (PMW) signal for controlling on / off switching of the switching elements Q1 to Q6 according to the control target, and supplies this to the corresponding switching elements Q1 to Q6.
[0022]
In addition, the EV-ECU 16 inputs the outside air temperature data detected by the outside air temperature sensor 30. The motor 10 is provided with a cooling device (not shown; see, for example, JP-A-2002-158321) using cooling water. The temperature of the cooling water is detected by a cooling water sensor 32, and the temperature data of the cooling water is input to the EV-ECU 16.
[0023]
The operation when detecting rotor damage in the above configuration will be described. FIG. 4 is a flowchart for detecting rotor damage. In the present embodiment, first, the motor rotation speed M is obtained using the rotor position sensor 18 (S10). Subsequently, a motor rotation speed error X is obtained by an equation of "X = NM" (S20). Here, N is a motor rotation speed instruction value output from the EV-ECU 16 when the motor rotation speed M is acquired. It is determined whether or not the acquired motor rotational speed error X is within a predetermined allowable range (S30). If the motor rotation speed error X is within a predetermined allowable range, it is determined that there is no abnormality in the motor rotation speed, and the processing here ends. If the motor rotation speed error X exceeds the predetermined allowable range, a process of adding 1 to the error determination counter Y is performed (S40). Thereafter, it is determined whether the error determination counter Y is equal to or greater than a predetermined threshold C (S50).
[0024]
If the error determination counter Y is less than the predetermined threshold C, the processing here ends. The value of the counter Y is held as it is until a predetermined time elapses, and is used when the processing from S10 to S40 is executed next.
[0025]
If the error determination counter Y is equal to or larger than the predetermined threshold value C, it is determined that the motor rotation speed is abnormal, and the integrated current value is calculated (S60). The current integrated value is obtained, for example, by detecting a current flowing through the motor at predetermined time intervals after the system startup of the electric vehicle, and integrating the detected current values. Next, the temperature Z of the stator, the outside air temperature, and the temperature of the cooling water are detected (S70). The correction of the stator temperature Z is performed based on these detected values (S80). For example, the stator temperature correction value Z 'is obtained by an equation of "Z' = ZE-E.times.outside air temperature-F.times.cooling water temperature". Here, E and F are predetermined coefficients. As a result, the influence of external factors (operating conditions) on the stator temperature Z is removed, and the stator temperature can be more appropriately evaluated.
[0026]
Subsequently, the allowable temperature Z0 in the current integrated value obtained in S60 is calculated (S90). The permissible temperature Z0 at each current integrated value can be calculated using, for example, a map as shown in FIG. 5, which shows the relationship between the current integrated value and the permissible temperature Z0. When Z0 is calculated, it is determined whether the stator temperature correction value Z 'is larger than Z0 (S100). If the stator temperature correction value Z 'is equal to or less than Z0, the processing here ends. If the stator temperature correction value Z 'is larger than Z0, it is determined that the stator temperature is abnormal. In this case, it is estimated that the rotor is damaged due to the detection of the abnormality of the motor speed and the abnormality of the stator temperature. Therefore, the warning lamp is turned on (S110), and the restriction on the motor drive is performed (S120). As a limitation of the motor drive, for example, there is a limitation on a motor maximum torque, a maximum rotation speed, and the like. Thereby, the user can recognize that an abnormality has occurred in the motor. In addition, by restricting the motor drive, further damage to the rotor can be prevented, and traveling safety can be ensured. In addition, by suppressing the progress of the rotor damage, it is possible to move to the repair place by self-propelled, and the vehicle is prevented from getting stuck.
[0027]
In the above embodiment, the abnormality determination of the stator temperature is performed based on the stator temperature correction value Z '. However, the abnormality determination of the stator temperature may be performed based on the stator temperature Z.
[0028]
As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be added to the above embodiment. It is apparent from the description of the appended claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.
[0029]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to reliably detect the damage of the rotor constituting the motor in the initial stage. Thereby, the safety of the vehicle using the motor as a driving force source can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main configuration of a motor for driving a vehicle.
FIG. 2 is a graph showing a behavior of a motor rotation speed and a transition of a stator temperature at an early stage of rotor damage.
FIG. 3 is a schematic configuration diagram of a rotor damage detection system 2 according to the embodiment.
FIG. 4 is a flowchart in the case of detecting rotor damage.
FIG. 5 is a view showing a map indicating a relationship between a current integrated value and an allowable temperature Z0.
[Explanation of symbols]
2 rotor damage detection system, 10 motors, 12 inverters, 14 batteries, 18 rotor position sensors, 20 relay units, 30 outside temperature sensors, 32 cooling water sensors.

Claims (3)

A rotor damage detection device that detects damage to a rotor that constitutes a motor for driving a vehicle,
Motor rotation state detection means for detecting a motor rotation state,
Stator temperature detecting means for detecting a stator temperature;
A motor rotation abnormality determination unit that determines whether the motor rotation state is a predetermined motor rotation abnormality state,
A stator temperature abnormality determining unit that determines whether the stator temperature is a predetermined abnormal temperature,
With
When the motor rotation state is a predetermined motor rotation abnormal state and the stator temperature is a predetermined abnormal temperature, it is determined that the rotor is damaged. A rotor damage detection device that detects damage to a rotor constituting a motor,
Motor rotation speed detection means for detecting the motor rotation speed,
Stator temperature detecting means for detecting a stator temperature;
A motor rotation abnormality determining unit that determines that the motor rotation speed is abnormal when a state in which the motor rotation speed is reduced by a predetermined value or more from a set value of the motor rotation speed occurs a predetermined number of times.
When the stator temperature is higher than a specified temperature set according to the amount of current flowing to the motor, a stator temperature abnormality determination unit that determines that the stator temperature is abnormal.
With
A rotor damage detection system, wherein when the motor rotation state is determined to be a motor rotation abnormal state and the stator temperature is determined to be an abnormal temperature, the rotor is determined to be damaged. A rotor damage detection device that detects damage to a rotor constituting a motor,
Motor rotation speed detection means for detecting the motor rotation speed,
Stator temperature detecting means for detecting a stator temperature;
Stator temperature correction means for correcting the stator temperature based on the operating conditions of the motor,
A motor rotation abnormality determining unit that determines that the motor rotation speed is abnormal when a state in which the motor rotation speed is reduced by a predetermined value or more from a set value of the motor rotation speed occurs a predetermined number of times.
When the correction value of the stator temperature is higher than a specified temperature set according to the amount of current flowing to the motor, a stator temperature abnormality determination unit that determines that the stator temperature is abnormal.
With
A rotor damage detection system, wherein when the motor rotation state is determined to be a motor rotation abnormal state and the stator temperature is determined to be an abnormal temperature, the rotor is determined to be damaged.

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