JP2008187770A - Motor position controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor position controller which can detect an open-phase without using another detector. <P>SOLUTION: An encoder 3 and a Hall element 4 detect the rotational position of a motor 5 which drives the variable vane 1A of a turbo charger 1. A turbo control unit 6 controls the above motor so that the detected rotational position of the motor may be the target position. Moreover, the turbo control unit 6 detects the open phase of the encoder signal of one-phase by comparing this count rate of the detection signal of the rotational position with the last count rate during initializing operation and that in a state of rotating at a fixed speed or over in one direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor position control device that uses a direct current motor to control a control target to a target position, and in particular, a motor position suitable for detecting a missing phase of a two-phase incremental encoder provided on a motor output shaft. The present invention relates to a control device.

  Conventionally, in a two-phase incremental encoder that detects the motor position using two encoders, as a method of detecting a phase loss of a signal, an absolute type angle detection device can be used in addition to an incremental encoder, In addition to the A phase and the B phase, one using a Z-layer encoder that outputs an inverted signal once per round is known (for example, see Patent Document 1).

JP 2005-207864 A

  However, these systems have a problem that the structure becomes complicated because a separate detection device is required in addition to the two-phase encoder.

  An object of the present invention is to provide a motor position control device capable of detecting a phase loss without using another detector.

(1) In order to achieve the above object, the present invention is provided on an output shaft of a motor that drives a controlled object, and is detected by a motor rotational position detecting means for detecting the rotational position of the motor, and the motor rotational position detecting means. And a motor position control device that controls the motor so that the rotational position of the motor is the target position, using a two-phase incremental encoder as the motor rotational position detection means. The control means is in the initialization operation and is rotating at a speed equal to or higher than a constant speed in one direction, and the current count value of the detection signal from the motor rotation position detection means and the previous count By comparing the values, the missing phase of the 1-phase encoder signal is detected.
With this configuration, it is possible to detect an open phase without using another detector. (2) In the above (1), it is preferable that the control unit detects that the encoder is missing when the two-phase incremental encoder of the motor rotation position detecting unit rotates a plurality of times and the phase loss is periodic. It is determined to be a phase.

  According to the present invention, it is possible to detect an open phase without using another detector.

  Hereinafter, the configuration and operation of a motor position control device according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a turbo control device that controls the blade position of the variable wing turbocharger to be a predetermined angle will be described as an example of the motor position control device.

First, the configuration of the turbo control device that is the motor position control device according to the present embodiment will be described with reference to FIG.
FIG. 1 is a configuration diagram of a turbo control device that is a motor position control device according to an embodiment of the present invention.

  The angle of the blade 1 </ b> A of the turbocharger 1 is variably controlled by the motor 5. By changing the angle of the blade 1 </ b> A, the pressurizing pressure of the turbocharger 1 can be changed. A driving force transmission mechanism 2 is provided between the output shaft of the motor 5 and the blade 1 </ b> A of the turbocharger 1. The driving force transmission mechanism 2 includes a first gear 2A attached to the output shaft of the motor 5, a second gear 2B that meshes with the first gear 2A and rotates the worm gear 2D, and a second gear 2D that is rotated by the worm gear 2D. 3 gear 2C and the above-mentioned worm gear 2D. The driving force of the motor 5 is transmitted to the first gear 2A-second gear 2B-worm gear 2D-third gear 2C, and the angle of the blade 1A of the turbocharger 1 is varied. The blade 1A of the turbocharger 1 can take an arbitrary angle between the fully open position and the fully closed position.

  A rotary encoder 3 (3A, 3B) consisting of two discs for detecting the rotational position of the motor is attached to the output shaft of the motor 5, and when the output shaft of the motor 5 rotates, it rotates in the same way. Near the outer periphery of the encoders 3A and 3B, two Hall elements 4 (4A and 4B) for converting the rotational position into a signal are arranged. Changes in magnetic flux density that change with the encoders 3A and 3B are detected by the Hall elements 4A and 4B, respectively. The encoders 3A and 3B and the Hall elements 4A and 4B constitute position detection means. Motor rotation position signals φA and φB, which are outputs of the Hall elements 4A and 4B, are input to a turbo control unit (CU) 6.

  The turbo control unit 6 up-counts or down-counts the motor rotation position signals φA and φB by a method described later with reference to FIGS. 2 and 3. Here, in order to detect the motor position, it is configured only by an incremental encoder, so the absolute position is not determined, and it is necessary to obtain the origin position first. Therefore, the turbo control unit 6 performs initialization prior to the start of normal control at least after starting energization. The initialization operates the motor in at least one direction (the blade 1A of the turbocharger 1 is fully closed or fully open). Subsequently, this point is determined as an operation reference by the count value of the encoder not changing for a certain period of time. In addition, after obtaining an operation reference point in one direction, the motor is operated in the opposite direction to find a point where the counter value does not change for a certain period of time. The operating range is grasped from the difference between Since the variable angle of the blade 1A per count is known, the turbo control unit 6 can detect the angle of the blade 1A with reference to the fully closed position or the fully opened position.

  The turbo control unit 6 is connected to an engine control unit (ECU) 7 which is a host control device. The ECU 7 calculates an appropriate angle of the blade 1A of the turbocharger 1 according to the driving state of the vehicle, and outputs it to the turbo control unit 6 as a target opening signal. The turbo control unit 6 sends a forward or reverse command to the motor 5 to perform feedback control so that the actual angle of the blade 1A detected by the motor rotation position signals φA and φB becomes the target opening.

Next, the detection principle of the motor rotation position in the motor position control apparatus according to the present embodiment will be described with reference to FIGS.
2 and 3 are explanatory diagrams of the principle of detection of the motor rotational position in the motor position control device according to the embodiment of the present invention.

  First, as shown in FIG. 2, the signals φA and φB from the encoder are 90 degrees out of phase. During forward rotation, the phase of the signal φA is delayed by 90 degrees, and during reverse rotation, the phase of the signal φA is advanced by 90 degrees. For example, the rotational direction of the motor can be determined by looking at the level of the signal of ΦB at the rising or falling of ΦA, and the rotational position of the motor can be detected by counting the number of pulses of the signal. .

  Specifically, it is as summarized in FIG. For example, when the signal φA is at a high level and the signal φB is rising, that is, when the signals φA and φB are at the time t1 in FIG. 2, the turbo control unit 6 counts up. When the signal φA is at the low level and the signal φB falls, that is, when the signals φA and φB are at the time t2 in FIG. 2, the turbo control unit 6 counts up. Further, when the signal φA rises and the signal φB is at the low level, that is, when the signals φA and φB are in the state at time t3 in FIG. 2, the turbo control unit 6 counts up. Further, when the signal φA falls and the signal φB is at a high level, that is, when the signals φA and φB are in the state of time t4 in FIG. 2, the turbo control unit 6 counts up.

  Further, when the signals φA and φB in the four examples shown in the lower part of FIG. 3 are in the state, the turbo control unit 6 counts down.

Next, the operation of the turbo control device that is the motor position control device according to the present embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4 is a flowchart showing the operation of the turbo control device which is the motor position control device according to the embodiment of the present invention. FIG. 5 is an operation principle diagram of a turbo control device which is a motor position control device according to an embodiment of the present invention.

  In step S10 of FIG. 4, the turbo control unit 6 starts the initialization process after the IGN SW is turned ON in response to the initialization instruction. In the initialization process, the motor is continuously operated in at least one direction (the blade 1A of the turbocharger 1 is in the fully closed position or the fully open position), and this point is determined as the operation reference by the encoder count value not changing for a certain period of time. . In addition, after obtaining an operation reference point in one direction, the motor is operated in the opposite direction to find a point where the counter value does not change for a certain period of time. The operating range is grasped from the difference between

  After starting the initialization process, in step S20, the turbo control unit 6 resets the encoder counter to zero.

  Next, in step S30, the turbo control unit 6 determines whether or not initialization is in progress. If initialization is in progress, the process proceeds to step S40; otherwise, the process returns to step S20.

  When initialization is in progress, in step S40, the turbo control unit 6 determines whether or not the motor has started to move in the forward rotation direction where the initialization is started. When forward rotation, the process proceeds to step S50, and when reverse rotation, the process proceeds to step S90. Whether forward rotation or reverse rotation is determined based on the principle described with reference to FIG.

  In step S50, the turbo control unit 6 determines whether or not the motor speed is greater than a preset speed A. If it becomes large, it will progress to step S60, and until it becomes large, it will return to step S20 and will repeat step s20-step S50. This is because when the motor starts rotating, the encoder may reverse momentarily due to the cogging torque of the motor, and the up-count may not continue normally. Whether or not the motor speed is equal to or higher than speed A is determined based on whether or not the number of up-counts within a predetermined time is equal to or higher than a predetermined value.

  When the motor speed becomes equal to or higher than the speed A, in step S60, the turbo control unit 6 takes the count value C into the nth count value Cn.

  In step S70, the turbo control unit 6 compares the previous count value Cn-1 with the count value Cn. If the difference is 1, the process proceeds to step S80. This means that a phase failure has occurred, and the process proceeds to step S130.

  Here, changes in the signals φA and φB and the count value will be described with reference to FIG. FIG. 5A shows the signal φA, FIG. 5B shows the signal φB, and FIG. 5C shows the count value. In the example of FIG. 5, the pulse signal indicated by the broken line in FIG. 5A is normal, and one pulse is missing in the state indicated by the solid line.

  When there is no phase loss, the count value is sequentially increased by one count as shown by a count value C1 shown in FIG. On the other hand, when a phase failure occurs, a phenomenon occurs in which the count value decreases by 1 during the count-up, as in the count value C2 shown in FIG.

  Therefore, in step S70 of FIG. 4, the previous count value Cn-1 is compared with the count value Cn, and if the difference is 1, it can be determined that the value is normal.

  When a phase loss occurs, in step S130, an encoder abnormality is notified to the host ECU 7 via a communication line such as CAN.

  If the normal count continues, in step S80, the next pulse input is awaited. If a pulse is input, the process returns to step S50, and steps S50 to S80 are repeated.

  On the other hand, in the initialization process, the motor rotates in the normal direction and then reverses. Therefore, when reverse rotation is determined in step S40, a phase failure is detected in steps S90 to S120 in the same manner as steps S50 to S80.

  The turbo control unit 6 includes a CPU. The logic shown in FIG. 4 is built in the CPU. Note that the logic of FIG. 4 may be configured by hardware outside the CPU.

  During the initialization process, the encoder 3 rotates a plurality of times from the fully closed position to the fully open position. When phase loss occurs due to encoder installation error, etc., phase loss is detected at least once for each rotation of the encoder, and multiple phases are detected when the encoder rotates multiple times. Moreover, it is detected with periodicity at the same timing. Therefore, it can be determined that the encoder phase is missing only when the phase loss is detected a plurality of times and with periodicity. By doing in this way, when the phase loss is detected only once due to the influence of disturbance or the like, it can be determined that the encoder is not abnormal, and the influence of disturbance or the like can be removed.

As described above, according to this embodiment, it is possible to detect an encoder phase loss with simple logic. Therefore, the position shift of the motor of the position control device using the motor can be prevented.

It is a block diagram of the turbo control apparatus which is a motor position control apparatus by one Embodiment of this invention. It is explanatory drawing of the detection principle of the motor rotational position in the motor position control apparatus by one Embodiment of this invention. It is explanatory drawing of the detection principle of the motor rotational position in the motor position control apparatus by one Embodiment of this invention. It is a flowchart which shows operation | movement of the turbo control apparatus which is a motor position control apparatus by one Embodiment of this invention. It is an operation | movement principle figure of the turbo control apparatus which is a motor position control apparatus by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turbocharger 2 ... Driving force transmission mechanism 3 ... Rotary encoder 4 ... Hall element 5 ... Motor 6 ... Turbo control unit 7 ... ECU

Claims (2)

Motor rotational position detection means provided on the output shaft of the motor that drives the controlled object and that detects the rotational position of the motor;
A motor position control device having control means for controlling the motor such that the rotation position of the motor detected by the motor rotation position detection means becomes a target position;
As the motor rotation position detection means, a two-phase incremental encoder is used,
The control means performs the initial count operation and the current count value of the detection signal from the motor rotation position detection means and the previous count value in a state of rotating at a speed equal to or higher than a constant speed in one direction. A motor position control device that detects a phase loss of an encoder signal of one phase by comparing. The motor position control device according to claim 1,
The motor position control is characterized in that the control means determines that an encoder phase is missing when the two-phase incremental encoder of the motor rotation position detecting means rotates a plurality of times and the phase is missing. apparatus.

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