JP5144322B2 - Electric motor control device - Google Patents

Description

  The present invention relates to an electric motor control device, and more particularly to an electric motor control device for controlling an electric motor mounted on a moving body such as an automobile.

  As an example of a conventional technique in various motor control apparatuses that are widely used for controlling an electric motor, there is a control apparatus described in Patent Document 1 (hereinafter referred to as a conventional technique). In the prior art, the terminal voltage of each phase of the electric motor is measured, and the measured terminal voltage is compared with a predetermined reference voltage. And the timing which switches the phase which applies a voltage based on a comparison result, ie, a commutation timing, is determined. More specifically, the commutation timing is defined as the time when the electrical angle changes by 30 ° from the time when any one of the measured terminal voltages crosses the reference voltage.

Further, in the conventional technology, the commutation timing is determined, and at the same time, whether or not the motor to be controlled is in a synchronized state is determined based on the terminal voltage of each phase of the motor. More specifically, in the related art, when the comparison result pattern obtained by comparing the terminal voltage of each phase of the electric motor with a predetermined reference voltage matches an ideal comparison result pattern stored in advance. It is estimated that the motor is in a synchronized state. That is, in the prior art, the commutation timing and the motor synchronization state are determined based on the terminal voltage of the motor without using a sensor that directly detects the rotation angle.
Japanese Patent Laid-Open No. 06-217591

  However, the above prior art has the following problems. In the above prior art, it is possible to determine whether or not the motor is in a synchronized state, but it is not possible to clearly determine whether or not the motor is no longer in a synchronized state due to reverse rotation. More specifically, when the motor is out of synchronization, for example, when the motor falls into a non-rotation state or falls into a step-out state other than when the motor rotates in reverse Can be considered. However, in the method of the above prior art, that is, the method of determining the commutation timing and the synchronization state of the motor based on the terminal voltage of the motor, it is clear that the motor is rotating in reverse in these various abnormalities. It cannot be judged.

  In order to solve the above-described problems, an object of the present invention is to provide an electric motor control device that can clearly determine that the electric motor is rotating in the reverse direction without using a sensor that directly detects the rotation angle. To do.

  In order to achieve the above object, the present invention has the following features.

  According to a first aspect of the present invention, there is provided estimation means for estimating a rotation angle of a rotating shaft of an electric motor for each predetermined angle based on a comparison result obtained by comparing a terminal voltage of each phase of the electric motor with a predetermined reference voltage. Measuring means for measuring a period from when the rotation angle is estimated by the estimation means until the next rotation angle is estimated, and a period measured by the measurement means And a reverse rotation detecting means for detecting that the electric motor is rotating in reverse when the ratio of the period measured immediately before the period is equal to or greater than a predetermined period ratio.

  According to a second invention, in the first invention, a plurality of sets of set values for detecting the state of the motor to be controlled are stored in advance, corresponding to each of the inertia moments of the rotating parts of the plurality of motors. And a setting means for presetting each set value corresponding to the moment of inertia of the rotating part of the electric motor to be controlled from among the set value set stored in the storage means.

  According to a third aspect, in the second aspect, a double period ratio is predetermined.

  According to a fourth aspect, in the third aspect, the rotational speed estimating means for estimating the rotational speed of the electric motor based on the rotational angle estimated by the estimating means, and the rotational speed estimated by the rotational speed estimating means are preset. When the rotation speed is equal to or higher than the high rotation speed threshold, the high rotation detection means for detecting that the rotation speed of the electric motor is high, and the rotation speed estimated by the rotation speed estimation means is less than or equal to a preset low rotation speed threshold value. And a low rotation detecting means for detecting that the rotation speed of the electric motor is low, and the storage means has a high rotation speed corresponding to each moment of inertia of the rotating portion of the electric motor as a set of set values. A set of threshold values and a low rotation speed threshold value is stored in advance, and the setting means is a set corresponding to the moment of inertia of the motor to be controlled, among the high rotation speed threshold value and low rotation speed threshold values stored in the storage means. of Presetting the rotational speed threshold and a low rotational speed threshold respectively and high rotation detecting means and the low-rotation detecting unit.

  According to a fifth aspect, in the fourth aspect, when the current flowing through the electric motor is equal to or greater than a predetermined current threshold value, the non-rotatable detecting means detects that the electric motor is not rotatable.

  According to a sixth invention, in the fifth invention, when reverse rotation of the electric motor is detected by the reverse rotation detection means, when high rotation of the electric motor is detected by the high rotation detection means, low rotation detection means detects the low motor speed. An abnormality counting means that counts the number of times that at least one abnormality has occurred when rotation is detected and when the inoperability of the electric motor is detected by the non-rotation detecting means, and counted by the abnormality counting means And an abnormality stopping means for stopping the supply of electric power to the electric motor when the number of abnormalities made exceeds a predetermined number.

  According to a seventh invention, in the sixth invention, when a predetermined stop period elapses after the supply of power to the motor is stopped by the abnormal stop means, the power supply to the motor is restarted. Supply means are further provided.

  In an eighth aspect based on the seventh aspect, an electric motor mounted on the moving body and provided in a fuel pump for supplying fuel to the moving body is controlled.

  ADVANTAGE OF THE INVENTION According to this invention, the motor control apparatus which can determine clearly that the electric motor is carrying out reverse rotation can be provided, without using the sensor which detects a rotation angle directly.

(First embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of an electric motor control device 1 according to the present embodiment. The electric motor control device 1 includes a control unit 101, an inverter 102, an estimation unit 103, and a measurement unit 104. In FIG. 1, an electric motor 105 is shown as a control target of the electric motor control device 1.

  When a rotation instruction to rotate the electric motor 105 is given from an instruction unit (not shown) or the like, the control unit 101 performs forced excitation control and induced voltage control for driving the electric motor 105 based on the induced voltage of each phase of the electric motor 105. While switching a well-known control process according to the rotation state of the electric motor 105, a control signal Cs for controlling the inverter 102 is generated and the electric motor 105 is driven. Further, the control unit 101 performs an abnormality detection process for detecting an abnormality that has occurred in the electric motor 105 based on the terminal voltage of each phase of the electric motor 105 in parallel with the rotation process. Details of the rotation processing and abnormality detection processing of the control unit 101 will be described later.

  The inverter 102 controls the open / close state of the switching element provided inside based on the control signal Cs generated by the control unit 101 in the same manner as a known inverter, and converts the power supplied from a power source (not shown) to an AC suitable for the motor 105. It is converted into electric power and supplied to the electric motor 105. The AC power supplied to the electric motor 105 by the inverter 102 according to this embodiment is U-phase, V-phase, and W-phase three-phase AC power.

  The electric motor 105 includes three terminals for receiving supply of AC power of U phase, V phase, and W phase. Electric motor 105 is a well-known three-phase AC motor that receives U-phase, V-phase, and W-phase three-phase AC power supplied from inverter 102 at each terminal, and rotates a rotor included therein with three-phase AC power. is there.

  The estimation unit 103 measures each terminal voltage of the electric motor 105 and estimates the rotation angle of the rotation shaft of the electric motor 105 using a known method based on the measurement result. The estimation unit 103 estimates the rotation angle of the rotation shaft of the electric motor 105 every time the rotation shaft rotates by a predetermined rotation angle, and generates an angle signal Ks indicating the estimated rotation angle. Note that the predetermined rotation angle may be an angle determined by the number of phases of the electric motor 105 and the number of poles of the rotor. In the description of the present embodiment, the description will be continued by taking as an example the case where the predetermined rotation angle is 60 °. Further, a well-known method for estimating the rotation angle of the rotating shaft of the electric motor 105 by the estimating unit 103 will be described later.

  The measurement unit 104 is a period from when the rotation angle is estimated by the estimation unit 103 until the next rotation angle is estimated, that is, a constant angle required for the rotation shaft of the electric motor 105 to rotate by a predetermined rotation angle. The period is measured each time the estimation unit 103 estimates the rotation angle. As a more specific example, the measurement unit 104 generates the angle signal Ks by the estimation unit 103 during the period from the generation of the angle signal Ks by the estimation unit 103 to the next generation of the angle signal Ks. Measure as a constant angle period in degrees. Then, every time the angle signal Ks is generated by the estimation unit 103, the measurement unit 104 determines the rotation angle estimated by the estimation unit 103 and the measurement of the rotation angle until the next rotation angle is measured. A measurement signal Ss indicating the angular period is generated.

  The above is the description of each configuration of the motor control device 1. Next, details of the rotation processing of the control unit 101 will be described. Of the rotation processing of the control unit 101, the above-described induced voltage processing is performed based on the result of processing the terminal voltage of each phase of the electric motor 105. The terminal voltage of each phase of the electric motor 105 is induced in the AC power voltage supplied to the terminal of each phase of the electric motor 105 by the inverter 102 and the coil of each phase provided inside when the electric motor 105 rotates. And the induced voltage to be added. The induced voltage process can be started when the electric motor 105 rotates stably and the induced voltage induced in the coils of the respective phases of the electric motor 105 reaches a required level. However, at the time of startup including when the electric motor 105 returns from the abnormally stopped state, since the rotation of the electric motor 105 is stopped, a sufficient level of induced voltage is not induced.

  Therefore, the control unit 101 virtually sets the terminal voltage pattern of each phase when the motor 105 is rotating stably when the motor 105 starts up, and the virtually set terminal voltage of each phase. A control signal Cs is generated based on the pattern, and the electric motor 105 is activated. The control unit 101 generates the control signal Cs based on the virtually set terminal voltage of each phase until the electric motor 105 rotates stably. As described above, the process of generating the control signal Cs based on the terminal voltage pattern of each phase virtually set by the electric motor 105 is referred to as a forced excitation process. Then, when the control unit 101 continues the forced excitation process, the motor 105 rotates stably and the induced voltage reaches a sufficient level, that is, the terminal voltage of each phase of the motor 105 reaches a sufficient level. When switching to the induced voltage process, the rotation process is continued. Further, even when the control unit 101 is performing the induced voltage process, if for some reason the rotation of the electric motor 105 becomes unstable and the level of the induced voltage decreases, the process is temporarily switched to the forced excitation process. After that, when the rotation of the electric motor 105 is stabilized again, the induced voltage processing is switched. That is, the control unit 101 according to the present embodiment continues the rotation process while appropriately switching between the forced excitation process and the induced voltage process according to the rotation state of the electric motor 105.

  The above is the detailed description of the rotation process of the control unit 101. In FIG. 1, the wiring for the motor 105 to perform rotation processing, that is, the wiring for the control unit 101 to directly measure the terminal voltage of each phase of the motor 105 is not shown.

  Next, processing for the control unit 101 to detect an abnormality of the electric motor 105 based on the terminal voltage of each phase of the electric motor 105 will be described. Therefore, first, an example of a known method in which the estimation unit 103 estimates the rotation angle of the rotation shaft of the electric motor 105 based on the terminal voltage of each phase of the electric motor 105 will be described with reference to FIG.

  (A) shown in FIG. 2 is a figure which each shows the pattern of the terminal voltage of each phase when the electric motor 105 is rotating stably. As an example, the estimation unit 103 has a predetermined reference voltage that is an intermediate value between the maximum value and the minimum value of the voltage applied to the terminal of the electric motor 105. The estimation unit 103 generates a pulse signal that alternately switches between a high level and a low level when one of the terminal voltages of each phase becomes equal to the reference voltage, as shown in FIG. The estimation unit 103 excludes the counter electromotive voltage shown in FIG. 2A from the comparison target with the reference voltage.

  When the electric motor 105 is rotating stably, the level of the pulse signal described above elapses during a period in which the rotation axis of the electric motor 105 changes by a predetermined rotation angle as shown in FIG. Every time you do it, it switches alternately. More specifically, in the present embodiment, since the predetermined rotation angle is 60 ° as described above, the pulse signal has a period of changing by 60 ° as shown in FIG. Every time you do it, it switches alternately.

  Therefore, the estimation unit 103 can estimate that the rotation shaft of the electric motor 105 has rotated by 60 ° when the level of the pulse signal is switched to either the high level or the low level. Then, every time the level of the pulse signal is switched to any level, the estimation unit 103 accumulates the angle by 60 ° and estimates the accumulated angle as the rotation angle of the rotating shaft of the electric motor 105. The estimation unit 103 can generate an angle signal Ks indicating the estimated rotation angle every time the rotation angle is estimated, that is, every time the level of the pulse signal is switched to any level.

  The above is a description of a known method in which the estimation unit 103 estimates the rotation angle of the rotation shaft of the electric motor 105 based on each terminal voltage of the electric motor 105. In the present invention, the method by which the estimation unit 103 estimates the rotation angle of the rotating shaft of the electric motor 105 is not limited to the above-described method, and any method based on the terminal voltage of each phase of the electric motor 105 can be used. Such a method may be used.

  Next, the abnormality detection process of the control unit 101 will be described in detail. As an example, the control unit 101 according to the present embodiment detects a reverse rotation, a low rotation, a high rotation, and a non-rotatable state of the electric motor 105 as an abnormality.

  The reverse rotation of the electric motor 105 is an abnormality caused by, for example, a failure in starting the electric motor 105. In addition, the low rotation of the electric motor 105 means that the rotation speed of the electric motor 105 is required, for example, when the electric motor 105 bites in a foreign object and the rotation shaft is in a semi-locked state, or the bearing of the rotation shaft is deformed. This is an abnormality that occurs when the rotational speed cannot be increased up to a predetermined low rotational speed threshold or less. Further, the high rotation speed of the electric motor 105 means that the rotation speed of the electric motor 105 is unnecessarily increased due to, for example, a high-speed step-out state due to a failure in starting the electric motor 105 or idling, and a predetermined high rotation speed. This is an abnormality that occurs when the threshold value is exceeded. Further, the impossibility of rotation of the electric motor 105 refers to, for example, locking of the rotating shaft due to a failure in starting the electric motor 105, short-circuiting of a coil or power element provided in the electric motor 105, rotating shaft due to foreign matter entering the electric motor 105 This is an abnormality caused by, for example, the lock and rotor being stuck for some reason.

  Of the abnormalities detected by the control unit 101, first, reverse rotation detection processing for detecting reverse rotation of the electric motor 105 as abnormal will be described. The estimation unit 103 measures the terminal voltage of each phase of the electric motor 105 as described above, but each terminal voltage measured by the estimation unit 103 is supplied to the terminal of each phase of the electric motor 105 by the inverter 102. The sum of the voltage of the alternating current power and the induced voltage induced in the coils of the respective phases provided therein as the motor 105 rotates. That is, (a) shown in FIG. 2 is induced in the AC power voltage supplied to each terminal from the inverter 102 and the coil provided for each phase inside the motor 105 as the motor 105 rotates. This is a voltage pattern obtained by adding the induced voltage.

  Here, the voltage pattern of the AC power supplied from the inverter 102 does not change regardless of the rotation direction of the rotating shaft of the electric motor 105, whereas the above-described induced voltage pattern is the rotation direction of the rotating shaft of the electric motor 105. It changes according to. For this reason, the pattern of each terminal voltage when the electric motor 105 is rotating backward is an irregular pattern with respect to the regular pattern shown in FIG. 2A when rotating stably. . That is, when the electric motor 105 rotates in the reverse direction, the estimation unit 103 compares each terminal voltage with an irregular pattern with the reference voltage.

  FIG. 3 is a diagram comparing the pulse signal shown in FIG. 2B when the electric motor 105 rotates stably and the pulse signal when the electric motor 105 rotates in reverse. When the motor 105 is rotating in the reverse direction, the estimation unit 103 compares each terminal voltage of the irregular pattern with the reference voltage, so that the pulse signal generated by the estimation unit 103 is irregular as shown in FIG. Become a pattern.

  As described above, the estimation unit 103 estimates the rotation angle every time the level of the pulse signal is switched, and the measurement unit 104 measures the above-described constant angle period every time the estimation unit 103 estimates the rotation angle. Therefore, the constant angle period measured each time the rotation angle is estimated by the estimation unit 103 when the electric motor 105 is rotating in reverse is compared to when the electric motor 105 is rotating stably. It will vary. The control unit 101 can detect that the electric motor 105 is rotating in the reverse direction when detecting that the constant angle period indicated by the measurement signal Ss varies.

  More specifically, the control unit 101 determines in advance a ratio between the constant angle period measured by the measurement unit 104 and the constant angle period measured immediately before the constant angle period based on the measurement signal Ss. When the ratio is equal to or greater than the constant angle period ratio, it is detected that the rotating shaft of the electric motor 105 is rotating in the reverse direction. Although various positive values can be set as the value of the constant angle period ratio, 2 is given as an example of a specific value of the constant angle period ratio.

  When 2 is predetermined as the value of the constant angle period ratio, the control is performed when the ratio of the constant angle period t2 shown in FIG. 3 and the constant angle period t1 measured immediately before the constant angle period t2 is 2 or more. The unit 101 can detect that the electric motor 105 is rotating in the reverse direction.

  FIG. 4 is a diagram illustrating an example of measured values of each terminal voltage and pulse signal when the electric motor 105 rotates stably and reversely. In FIG. 4A, a regular pulse signal is generated, whereas in FIG. 4B, an irregular pulse signal is generated. The motor control device 1 according to the present embodiment determines that the motor 105 is rotating in the reverse direction when an irregular pulse signal as shown in FIG. 4B is generated by the above-described method. . In addition, since the terminal voltage of each phase in (a) shown in FIG. 4 is the voltage and the induced voltage of the alternating current power supplied in order to drive the electric motor 105 by a known chopper drive system, It is added that the waveform is not exactly the same as the terminal voltage of each phase of the schematic pattern shown in FIG. 2, but corresponds to the terminal voltage of each phase of the schematic pattern shown in FIG. Moreover, the drive system for the motor control apparatus 1 according to the present invention to drive the motor 105 is not limited to the chopper drive system.

  Next, a prescribed rotation detection process for detecting low and high rotations of the electric motor 105 as abnormal among the abnormalities detected by the control unit 101 will be described. The control unit 101 calculates the number of rotations per unit time of the rotating shaft of the electric motor 105 based on the rotation angle indicated by the measurement signal Ss. An example of the process in which the control unit 101 calculates the rotation speed of the electric motor 105 includes a process of differentiating the rotation angle with time. And the control part 101 detects the low rotation and high rotation of the electric motor 105 as abnormality by comparing the calculated rotation speed with the above-mentioned predetermined low rotation speed threshold value and high rotation speed threshold value, respectively.

  More specifically, the control unit 101 detects that the rotation speed of the rotating shaft of the electric motor 105 is low when the calculated rotation speed is equal to or lower than the low rotation speed threshold. In addition, the control unit 101 detects that the rotation speed of the rotating shaft of the electric motor 105 is high when the calculated rotation speed is equal to or higher than the high rotation speed threshold.

  Here, the setting of the low rotation speed threshold and the high rotation speed threshold will be described. In the present invention, the reason why it is detected that the electric motor 105 is rotating at a low speed or a high speed is to detect a state in which the electric motor 105 is idling or a half-locked state as described above. However, the number of rotations to be determined to be low or high depends on the motor specifications such as the moment of inertia of the rotating part including the rotating shaft and the rotor. That is, it is necessary to preset in advance in the control unit 101 a low rotation speed threshold and a high rotation speed threshold that are different from each other according to the specification of the motor to be controlled by the motor control device 1.

  Further, the control unit 101 according to the present embodiment includes a forced excitation period indicating a period from the start of the forced excitation process at the time of starting the motor to the switching to the induced voltage process, to the moment of inertia of the rotating part of the motor to be controlled. It may be calculated and set in advance based on the specifications. Furthermore, a set of values of the low rotation speed threshold value, the high rotation speed threshold value, and the forced excitation period may be set to correspond to one specification electric motor, and a plurality of value sets may be set in the control unit 101 in advance.

  FIG. 5 is a diagram showing a TN characteristic diagram (torque-rotational speed characteristic diagram) as an example of only three pairs of a low rotational speed threshold value and a high rotational speed threshold value that are predetermined according to the moment of inertia of the electric motor. It is. FIG. 5 also shows a forced excitation time that is predetermined according to the moment of inertia of the electric motor. It is clear from FIG. 5 that only a plurality of sets of values of the low rotation speed threshold value, the high rotation speed threshold value, and the forced excitation period can be set in advance according to the moment of inertia of each electric motor to be controlled.

  Further, if a set of optimum values can be selected from a plurality of preset value sets according to the specification of the motor to be controlled, a single motor control device 1 can be used for a plurality of types of motors. Can be controlled. For this purpose, an input unit may be provided in the motor control device 1. More specifically, for example, by providing two switching elements that can be switched between open and closed states as an input unit in the motor control device 1, a set of four types of values according to the combination of the open and closed states of the two switching elements. One set of can be selected. What can be used as the input unit is not limited to the switching element that can switch the open / close state, and any input unit can be used as long as one set can be designated according to the specifications of the motor. Good.

  As described above, a plurality of sets of values of the low rotation speed threshold value, the high rotation speed threshold value, and the forced excitation period are set in advance in the control unit 101, and one value set is set according to the specification of the motor to be controlled. By providing an input unit so that the motor can be selected, a set of a low rotation speed threshold, a high rotation speed threshold, and a forced excitation period according to the motor with different specifications can be obtained without producing a motor control device for each motor with different specifications. One electric motor control device 1 that can be selected and controlled can be provided.

  Next, non-rotation detection processing for detecting, as an abnormality, a non-rotatable state of the electric motor 105 among abnormalities detected by the control unit 101 will be described. When a motor to be controlled by the motor control device 1 according to the present invention is applied with a load torque while rotating, a load current according to the magnitude of the load torque, that is, three-phase AC power supplied to the motor Current increases. Therefore, it is possible to determine whether or not the motor cannot rotate by setting a threshold value in advance according to the magnitude of the current that flows when a load torque that makes the motor non-rotatable is applied. More specifically, the magnitude of the current when the motor 105 becomes non-rotatable is preset in the control unit 101 as a current threshold, and the magnitude of the AC power supplied to the motor 105 is greater than or equal to the current threshold. Then, the control unit 101 can detect that the electric motor 105 is in a non-rotatable state. The control unit 101 may measure the magnitude of the AC power supplied to the electric motor 105 via the estimation unit 103 and the measurement unit 104, or may directly measure the magnitude. In addition, the current measured by the control unit 101 may be any current of AC power of each phase.

  The above is the detailed description of the process in which the control unit 101 according to the present embodiment detects an abnormality of the electric motor 105. Next, the control unit 101 according to the present embodiment determines whether or not an abnormality has occurred in the electric motor 105 while performing the above-described processing, and when the abnormality has occurred, the electric motor 105 is temporarily stopped and then returned. The series of processes up to will be described with reference to the flowchart of FIG. In addition, the control part 101 which concerns on this embodiment shall perform the rotation process mentioned above in parallel with the process shown in the flowchart of FIG.

  In step S101, the control unit 101 initializes a variable N stored in a storage unit (not shown) to zero in order to count the number of times that an abnormality has occurred. When the control section 101 completes the process step of step S101, the control section 101 advances the process to step S102.

  In step S102, the control unit 101 determines whether or not a rotation instruction is given from an instruction unit (not shown). When the control unit 101 determines in step S102 that a rotation instruction has been given, the process proceeds to step S103. On the other hand, when the control unit 101 determines in step S102 that a rotation instruction has not been given, the process proceeds to step S117.

  In step S103, the control unit 101 determines to continue the rotation process described above. When the control section 101 completes the process step of step S103, the control section 101 advances the process to step S104.

  In step S104, the control unit 101 performs the reverse rotation detection process described above, and determines whether or not the electric motor 105 is rotating in reverse. When the control unit 101 determines in step S104 that the electric motor 105 is rotating in reverse, the process proceeds to step S105. On the other hand, when the control unit 101 determines in step S104 that the electric motor 105 is not reversely rotated, the control unit 101 advances the process to step S111. In addition, when the process of step S104 is completed, the control unit 101 deletes information regarding reverse rotation of a storage unit (not shown).

  In step S105, the control unit 101 increments the variable N described above by 1, and counts that an abnormality has occurred only once. When the control section 101 completes the process step of step S105, the control section 101 advances the process of step S106.

  In step S106, the control unit 101 generates a rotation stop signal for notifying an instruction unit (not shown) in advance that the rotation of the electric motor 105 is stopped. When the control section 101 completes the process step of step S106, the control section 101 advances the process to step S107.

  In step S107, the control unit 101 performs a pause process for generating a control signal Cs for temporarily stopping the electric motor 105. When a predetermined pause period for completing the process of step S107 and temporarily stopping the process has elapsed, the control unit 101 advances the process to step S108. The temporary stop period in step S107 may be any length, but a specific example is 100 msec. Further, when the motor control device 1 according to the present invention is used to control an electric motor that drives a water pump mounted on an automobile or the like or an electric motor that drives a fuel pump, the automobile is overheated by stopping the water pump. The temporary stop period may be determined in advance in consideration of a period during which the vehicle engine is not stopped due to a period during which the fuel pump is stopped. Further, in step S107, the control unit 101 further performs a process of determining the type of abnormality detected, and when the type of abnormality is reverse rotation, the above-described low rotation, high rotation, or the like, further than the specific example described above. The electric motor 105 may be paused for a short pause period and then restarted immediately. The control signal Cs generated by the control unit 101 to stop the electric motor 105 is any signal as long as it can stop the supply of AC power from the inverter 102 to the electric motor 105. Good.

  In step S108, the control unit 101 determines whether or not the value of the variable N described above is equal to or greater than a predetermined abnormality detection count IK. When the control unit 101 determines in step S108 that the value of the variable N is equal to or greater than the abnormality detection count IK, the control unit 101 advances the process to step S109. On the other hand, when the control unit 101 determines in step S108 that the value of the variable N is not greater than or equal to the abnormality detection count IK, the control unit 101 proceeds to step S113. When the number of occurrences of the abnormality of the electric motor 105 becomes equal to or more than a predetermined abnormality detection number IK, the control unit 101 performs an abnormal stop process described later, but the control unit 101 performs the process of step S108. It is possible to prevent erroneous determination of an error due to an erroneous determination of an error by estimating the error of the estimation unit 103 or the rotation speed of the electric motor 105 by sudden acceleration or rapid deceleration.

  In step S109, the control unit 101 performs an abnormal stop process for generating a control signal Cs for abnormally stopping the electric motor 105. The control unit 101 advances the process to step S110 when a predetermined abnormal stop period for completing the process of step S109 and abnormally stopping has elapsed. The abnormal stop period in step S109 may be any period, but is preferably longer than the above-described temporary stop period. In addition, if the restart of the electric motor 105 is frequently repeated, an electric circuit related to the control of the electric motor 105 including the electric motor control device 1 according to the present invention may generate extra heat due to the inrush current at the start of the electric motor 105. The period required for the temperature of these electric circuits to fall to a preferable temperature may be defined as an abnormal stop period. Moreover, 30 sec is mentioned as a specific example of the abnormal stop period. As described above, the control signal Cs generated by the control unit 101 to stop the electric motor 105 is any signal that can stop the supply of AC power from the inverter 102 to the electric motor 105. It may be a signal.

  In step S110, the control unit 101 initializes a variable N to zero. When the control section 101 completes the process of step S110, the control section 101 returns the process to step S101. The control unit 101 returns the process to step S101, and when the rotation instruction is given, determines to continue the rotation process again in step S102. As a result, the control unit 101 can restart the supply of AC power to the motor 105 after performing the abnormal stop process and stopping the electric motor 105 for the abnormal stop period. When receiving, the electric motor 105 can be automatically returned to the rotating state and the rotation process can be continued. Moreover, since the control part 101 can restart supply of the alternating current power to the electric motor 105 after carrying out an abnormal stop process and stopping the electric motor 105 only for an abnormal stop period, the electric motor control apparatus 1 which concerns on this invention is used. By using it to control an electric motor for driving a pump mounted on an automobile or the like, the automobile can be evacuated.

  In step S111, the control unit 101 performs the specified rotation detection process described above, and determines whether or not the rotation speed of the rotating shaft of the electric motor 105 is equal to or lower than a preset low rotation speed threshold and whether or not it is equal to or higher than a high rotation speed threshold. Determine whether. More specifically, in step S <b> 111, the control unit 101 determines when the rotation speed of the rotation shaft of the electric motor 105 calculated as described above is equal to or lower than the low rotation speed threshold and equal to or higher than the high rotation speed threshold. When it is determined that it is at least one of them, the process proceeds to step S105. On the other hand, when the control unit 101 determines in step S111 that the rotation speed of the rotating shaft of the electric motor 105 is not lower than the low rotation speed threshold and not higher than the high rotation speed threshold, the process proceeds to step S112.

  In step S112, the control unit 101 performs the non-rotation detection process described above, and determines whether or not the magnitude of the alternating current supplied to the electric motor 105 is equal to or greater than a predetermined current threshold and the electric motor 105 is non-rotatable. Judging. When the control unit 101 determines that the magnitude of the alternating current supplied to the electric motor 105 is greater than or equal to the current threshold value, the control unit 101 proceeds to step S105. On the other hand, when the control unit 101 determines in step S112 that the magnitude of the alternating current supplied to the electric motor 105 is not greater than or equal to the current threshold value, the control unit 101 proceeds to step S113.

  In step S113, the control unit 101 determines whether or not the forced excitation process is being performed in the parallel rotation process described above. When the control unit 101 determines in step S113 that the forced excitation process is being performed, the control unit 101 returns the process to step S101. On the other hand, when determining in step S113 that the forced excitation process has not been performed, the control unit 101 advances the process to step S114.

  In step S114, the control unit 101 determines whether or not the electric motor 105 continues to rotate stably. More specifically, the control unit 101 sequentially stores the constant angle period indicated by the measurement signal Ss each time the measurement signal Ss is generated while performing the processing shown in the flowchart of FIG. If a predetermined number of constant angle periods are stored, and all of the stored constant angle periods are substantially the same as the period during which the electrical angle changes by 60 ° when the electric motor 105 rotates stably. It is determined that the electric motor 105 continues to rotate stably. When the control unit 101 determines in step S114 that the electric motor 105 continues to rotate stably, the control unit 101 advances the process to step S115. On the other hand, when it is determined in step S114 that the electric motor 105 does not continue the stable rotation, the control unit 101 returns the process to step S101. Note that the number of constant angle periods that the control unit 101 sequentially stores may be any number as long as it can be determined that the electric motor 105 continues to rotate stably. As a specific example, There are 48 examples.

  In step S115, the control unit 101 initializes a variable N to zero. When the control section 101 completes the process step of step S115, the control section 101 advances the process to step S116.

  In step S116, the control unit 101 generates a normal rotation signal for notifying an instruction unit (not shown) that the electric motor 105 is stably rotating. When the process of step S116 is completed, the control unit 101 returns the process to step S101.

  In step S117, the control unit 101 determines whether or not the rotation processing described above is performed in parallel. When the control unit 101 determines in step S117 that the rotation processing is in parallel, the control unit 101 advances the processing to step S118. On the other hand, when the control unit 101 determines in step S117 that the rotation processing is not performed in parallel, the control unit 101 advances the processing to step S119.

  In step S118, the control unit 101 performs a rotation stop process for generating a control signal Cs for stopping the rotation of the electric motor 105. When the control section 101 completes the process step of step S118, the control section 101 advances the process to step S119. Note that the control signal Cs generated by the control unit 101 in step S118 may be the same signal as the control signal Cs described in step S107 or step S109.

  In step S119, the control unit 101 generates a rotation stop signal for notifying an instruction unit (not shown) that the rotation of the electric motor 105 is stopped. When the control section 101 completes the process step of step S119, the control section 101 returns the process to step S101.

  The above is description of the process of the control part 101 which concerns on this embodiment. By performing the processing shown in the flowchart of FIG. 6, the control unit 101 can clearly determine that the motor is rotating in reverse without using a sensor that directly detects the rotation angle of the rotating shaft of the motor 105. it can. Furthermore, the control unit 101 can determine that an abnormality has occurred in the motor and the type of abnormality that has occurred by performing the processing shown in the flowchart of FIG. 6. Further, the control unit 101 performs the processing shown in the flowchart of FIG. 6 to count the number of times that an abnormality has occurred when any of the above-described abnormalities occurs, and the number of times the abnormality has been detected is determined in advance. When it becomes IK or more, the electric motor 105 can be abnormally stopped. Further, even after the motor 105 is abnormally stopped, when a rotation instruction is given from an instruction unit (not shown), the supply of AC power to the motor 105 is resumed when a predetermined period has elapsed, The rotation of the electric motor 105 can be restored. Further, as described above, the control unit 101 can restart the supply of AC power to the motor 105 after performing the abnormal stop process and stopping the electric motor 105 for the abnormal stop period. By using the electric motor control device 1 to control an electric motor for driving a pump mounted on an automobile or the like, the vehicle can be retracted.

  The electric motor control apparatus 1 according to the present invention is mounted on a moving body such as an automobile, for example, and a fuel pump shown in FIG. 7 for controlling an electric motor provided in a fuel pump that supplies fuel to the moving body. It can be used as a controller. According to the electric motor control device 1 according to the present embodiment, a sensor for directly detecting the rotation angle of the rotating shaft of the electric motor is not required, so that the cost reduction of the fuel pump module including the fuel pump controller is realized. Furthermore, since the sensor and the sensor wiring are not required, the fuel pump module can be reduced in size.

  Further, by applying the electric motor control device 1 according to the present invention to the fuel pump controller as shown in FIG. 7, it is not necessary for the ECU to perform the process of detecting the abnormality of the electric motor 105, thereby reducing the processing load of the ECU. Further, it is possible to provide an electric fuel pump controller that can control stop and return of the electric motor in response to an abnormality occurring in the electric motor without depending on the processing of the ECU.

  In the description of the present embodiment, the case where the motor 105 is a three-phase induction motor has been described as an example. However, the control target of the motor control device 1 according to the present invention is not limited to the three-phase induction motor. Another example of the control target of the motor control device 1 according to the present invention is a two-phase motor. When a two-phase motor is to be controlled, the two-phase motor is driven using a known H-bridge circuit instead of the inverter 102, and the above-described processing is performed based on the terminal voltage of each phase of the two-phase motor. .

  Further, the processing of the control unit 101 described above is realized by the CPU interpreting and executing predetermined program data stored in a storage device (ROM, RAM, hard disk, etc.) that can execute the processing procedure described above. Also good. The CPU may be a CPU constituting an ECU (Electric Control Unit) mounted on a moving body such as an automobile. In this case, the program data may be introduced into the storage device via the storage medium, or may be directly executed from the storage medium. The storage medium includes a semiconductor memory such as a ROM, a RAM, and a flash memory, a magnetic disk memory such as a flexible disk and a hard disk, an optical disk memory such as a CD-ROM, a DVD, and a BD, and a memory card.

  Although the present invention has been described in detail above, the above description is merely an example of the present invention in all respects and is not intended to limit the scope thereof. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the motor control apparatus which can detect the abnormality of an electric motor can be provided, without using the sensor which directly detects the rotation angle of an electric motor, for example, the motor control apparatus mounted in moving bodies, such as a motor vehicle Available to:

The block diagram which shows schematic structure of the motor control apparatus which concerns on this invention The figure explaining the method of measuring the rotation angle of the rotating shaft of an electric motor The figure explaining the method of detecting reverse rotation of the rotating shaft of an electric motor Diagram for comparing the terminal voltage of each phase of the motor The figure which shows an example of a low rotation threshold value, a high rotation threshold value, and a forced excitation period The flowchart which shows the process of the control part which concerns on this invention The figure which shows the example of application of the electric motor control apparatus which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor control apparatus 101 Control part 102 Inverter 103 Estimation part 104 Measurement part 105 Electric motor

Claims (8)

The terminal voltage of each phase of the motor is compared with a predetermined reference voltage that is an intermediate value between the maximum value and the minimum value of the terminal voltage, and each terminal voltage is compared with the reference voltage except for the back electromotive voltage. And an estimation means for estimating the rotation angle of the rotating shaft of the electric motor for each angle at the timing ;
A measurement unit that measures a period from when the rotation angle is estimated by the estimation unit to when the rotation angle is estimated next, each time the rotation angle is estimated by the estimation unit;
Reverse rotation detection means for detecting that the electric motor is rotating in reverse when the ratio of the period measured by the measurement means and the period measured immediately before the period is equal to or greater than a predetermined period ratio. An electric motor control device comprising: Storage means for storing in advance a set of a plurality of set values for detecting the state of the motor to be controlled, corresponding to each of the moments of inertia of the rotating parts of the plurality of motors;
2. The apparatus according to claim 1, further comprising: a setting unit that presets each set value corresponding to the moment of inertia of the rotating portion of the electric motor to be controlled among the set of set values stored in the storage unit. Electric motor control device.   The motor control device according to claim 2, wherein the period ratio of twice is predetermined. A rotational speed estimating means for estimating the rotational speed of the electric motor based on the rotational angle estimated by the estimating means;
A high rotation detection means for detecting that the rotation speed of the electric motor is high when the rotation speed estimated by the rotation speed estimation means is equal to or higher than a preset high rotation speed threshold;
A low rotation detection means for detecting that the rotation speed of the electric motor is low when the rotation speed estimated by the rotation speed estimation means is equal to or lower than a preset low rotation speed threshold;
The storage means stores in advance a set of the high rotation speed threshold and the low rotation speed threshold corresponding to each moment of inertia of the rotating part of the electric motor as the set of set values,
The setting means includes a set of the high rotation speed threshold and the low rotation speed corresponding to the moment of inertia of the electric motor to be controlled among the set of the high rotation speed threshold and the low rotation speed threshold stored in the storage means. The electric motor control device according to claim 3, wherein a rotation speed threshold value is preset for each of the high rotation detection unit and the low rotation detection unit.   The motor control device according to claim 4, further comprising non-rotation detecting means for detecting that the motor cannot rotate when a current flowing through the motor is equal to or greater than a predetermined current threshold. When reverse rotation of the electric motor is detected by the reverse rotation detection means, when high rotation of the electric motor is detected by the high rotation detection means, and when low rotation of the electric motor is detected by the low rotation detection means And an abnormality counting means for counting the number of times that at least one abnormality has occurred when the non-rotation detecting means detects that the electric motor is inoperable,
The motor control device according to claim 5, further comprising an abnormality stopping unit that stops supply of electric power to the electric motor when the number of abnormalities counted by the abnormality counting unit exceeds a predetermined number. .   The apparatus according to claim 6, further comprising a resupply unit that restarts the supply of electric power to the electric motor when a predetermined stop period has elapsed after the supply of electric power to the electric motor is stopped by the abnormal stop unit. The motor control device described.   The electric motor control device according to claim 7, wherein the electric motor control device is mounted on the moving body and controls an electric motor provided in a fuel pump for supplying fuel to the moving body.

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