JP2017073945A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device that is able to improve response to deceleration while maintaining accuracy in stopping a rotor at a target position.SOLUTION: This electronic control device comprises: a motor having a rotor that rotates by electrically conducting a plurality of electrical conduction phases; an encoder that outputs a pulse-like encoder signal in synchronization with the rotation of the rotor; a control section that controls on and off of electrical conduction to the electrical conduction phase on the basis of a change in encoder signal; and a speed range determination section that determines which speed range among an acceleration range, a constant speed range, and a deceleration range, rotation of the rotor falls in. If the rotor is in the deceleration range, the control section exerts control such that a phase relating to off-timing of electrical conduction to the electrical conduction phase is delayed with respect to a change point of an encoder signal, and thereby force acts in a direction opposite the rotating direction of the rotor.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electronic control device that sequentially switches energized phases of a motor and rotationally drives a rotor to a target position.

  In shift-by-wire, a shift change (range switching) is realized by energizing a plurality of energized phases and driving a motor in accordance with a driver's operation. In order to ensure the responsiveness and accuracy with respect to the driver's operation, a high speed rotation of the motor and a reliable deceleration are required. In order to achieve this, energization accuracy for each phase is required, but the drive circuit that outputs drive signals to the inverter and inverter is affected by conditions such as element characteristics and temperature. There is a limit to improving the energization accuracy based on this.

  On the other hand, in the motor control device described in Patent Document 1, a speed phase advance correction amount Ks that is a phase advance amount of the energized phase with respect to the current position of the rotor is introduced, and the correction amount Ks is variable according to the rotor rotational speed. I have to. Thereby, the phase advance amount of the energized phase with respect to the rotational phase of the rotor can be corrected according to the state of rotation of the rotor. For example, at the initial stage of rotation of the rotor, the correction amount Ks is reduced to increase the torque so that the acceleration performance is improved, and the correction amount Ks is increased as the rotor speed increases, thereby stabilizing the rotation. Can be realized.

JP 2004-23931 A

  In the motor control device described in Patent Document 1, the correction amount Ks is controlled to be small in the deceleration region where the rotational speed of the rotor is small. However, the deceleration region is long enough for high-accuracy stopping at the target position. That is, it was necessary to secure the time required for stopping. In other words, there is a possibility that the response to deceleration is not sufficient. This is because it is difficult to select a circuit component that can achieve both the rise of current required for acceleration and the fall of current required for rapid deceleration.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electronic control device that can improve the responsiveness during deceleration while maintaining the accuracy of stopping at a target position.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

  To achieve the above object, the present invention provides a motor (10) having a rotor (12) that rotates by energization of a plurality of energized phases, and an encoder that outputs a pulsed encoder signal in synchronization with the rotation of the rotor. (20), the control unit (40) for controlling on / off of energization to the energized phase based on the change of the encoder signal, and the rotation of the rotor is in any of the acceleration region, constant speed region, and deceleration region. A speed range determination unit (30) for determining whether or not. Then, when the rotor is in the deceleration range, the control unit delays the phase related to the off timing of energization to the energized phase with respect to the change point of the encoder signal, so that the direction opposite to the rotation direction of the rotor It is characterized in that it is controlled so that force is exerted on.

  According to this, since the fall of the current related to turning off the energization to the energized phase is delayed as compared with the conventional control, a force can be applied in the direction opposite to the rotation direction of the rotor. For this reason, idling of the rotor can be suppressed, and angular acceleration related to deceleration can be increased. Therefore, the time until the rotor rotating in the constant speed region stops, that is, the time in the deceleration region can be shortened. That is, the responsiveness to deceleration can be improved.

It is a block diagram which shows schematic structure of the electronic controller in 1st Embodiment. It is a front view which shows a part of structure of a stator and a rotor. It is a front view which shows a part of structure of an encoder. It is a flowchart which shows operation | movement of the electronic control apparatus at the time of an encoder signal change. It is a conversion table which associates the current position and phase advance correction amount of the rotor with the energized phase to be energized. It is a timing chart concerning control by an electronic control unit. It is a flowchart which shows operation | movement of the electronic controller after expiration of a delay timer. It is a figure which shows the mode of the force applied to a rotor. It is a figure which shows the change of the rotation speed of the rotor with respect to time. It is a timing chart concerning control by the electronic controller in a 2nd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same or equivalent parts.

(First embodiment)
Initially, with reference to FIGS. 1-3, schematic structure of the electronic controller which concerns on this embodiment is demonstrated.

  This electronic control device is mounted on a vehicle and is a device that controls shift changes by an automatic transmission. In particular, it is mounted on a vehicle that employs a so-called shift-by-wire, in which the ECU (control unit) switches the range by controlling the stepping motor in accordance with the driver's range switching operation.

  As shown in FIG. 1, the electronic control unit 100 includes a motor 10 that constitutes an automatic transmission, an encoder 20 that outputs a pulsed signal in synchronization with the rotation of the motor 10, and a speed range of rotation of the motor 10. A speed range determination unit 30 for determining the control unit 40 and a control unit 40 as an electronic control unit (ECU). The control unit 40 controls driving of the motor 10 via a driving circuit 50 that supplies current to the motor 10.

  The electronic control device 100 is electrically connected to a shift operation unit 200 operated by a driver. The shift operation unit 200 detects the driver's range switching operation and outputs range information desired by the driver to the control unit 40.

  The electronic control unit 100 is mechanically connected to a gear box 400 that transmits the power of the engine 300 to the wheels by changing the torque and the rotational speed. The gear box 400 changes the combination of gears to be fitted by the power of the motor 10 and changes the power transmission path of the engine 300. That is, a shift change is performed by the power of the motor 10.

  As the motor 10 in the present embodiment, a stepping motor (switched reluctance motor: SR motor) is employed. As shown in FIG. 2, the motor 10 is a motor in which both the stator 11 and the rotor 12 have a salient pole structure, and has a simple configuration that does not require a permanent magnet. For example, twelve salient poles 11a are formed at equal intervals on the inner peripheral portion of the cylindrical stator 11, whereas, for example, eight salient poles 12a are equally spaced on the outer peripheral portion of the rotor 12. Is formed. As the rotor 12 rotates, the salient poles 12a of the rotor 12 are sequentially opposed to the salient poles 11a of the stator 11 via a minute gap. Windings 13 respectively assigned to the U phase, the V phase, and the W phase are wound around the salient pole 11a of the stator 11 in order. Note that the number of salient poles 11a of the stator 11 and the number of salient poles 12a of the rotor 12 may be changed as appropriate.

  When a current flows through the winding 13, a magnetic flux is generated inside the corresponding salient pole 11a of the stator 11 and excited. When the salient pole 12a of the rotor 12 is attracted to the magnetized salient pole 11a, the rotation of the rotor 12 is realized. For example, when current flows in the order of the U phase, the V phase, and the W phase, the rotor 12 rotates clockwise with respect to the paper surface.

  The encoder 20 is composed of a magnetic rotary encoder. Specifically, as shown in FIG. 3, an annular rotary magnet 21 in which N poles and S poles are alternately magnetized at equal pitches in the circumferential direction is fixed to the rotor 12. The rotary magnet 21 is fixed so as to be coaxial with the rotor 12, and rotates with the rotation of the rotor 12. In the rotary magnet 21 in this embodiment, the magnetization pitch of the N pole and the S pole is set to 7.5 degrees.

  The encoder 20 has magnetic detection elements 22 and 23 such as Hall elements at positions facing the rotary magnet 21. The magnetic detection element 22 outputs an A signal among the encoder signals. On the other hand, the magnetic detection element 23 outputs a B signal among the encoder signals. The encoder signals output from the magnetic detection elements 22 and 23 are High when the magnetic detection elements 22 and 23 face the N pole of the rotary magnet 21, and are Low when the magnetic detection elements 22 and 23 face the S pole. That is, the encoder signal is output so as to periodically repeat High and Low every time the rotor 12 and the rotary magnet 21 rotate 7.5 degrees. The magnetic detection element 22 and the magnetic detection element 23 are arranged 48.75 degrees apart from each other in the rotation direction. For this reason, the phase difference between the A signal and the B signal is 3.75 degrees in terms of the rotation angle of the rotor 12. In other words, the B signal is output with a phase delay of ¼ period with respect to the A signal. The encoder 20 outputs the A signal and the B signal to the control unit 40. The control unit 40 detects the rotation angle of the rotor 12 by counting the falling edge of the A signal and the B signal and the change point of the falling edge, that is, the edge of the signal, and switches the energized phase to be energized. As described above, since the phase difference between the A signal and the B signal is 3.75 degrees as the rotation angle of the rotor 12, the rotor 12 rotates 3.75 degrees while counting one encoder signal. Since the count number is incremented when the rotor 12 rotates forward and counts down when the rotor 12 rotates backward, the current position of the rotor 12 can be uniquely determined by the count number if the initial value of the counter is known. it can.

  The speed range determination unit 30 determines the speed range based on the angle difference X between the rotation angle of the current position of the rotor 12 and the rotation angle of the target position. The speed range includes an acceleration range where the angle difference X is greater than or equal to a predetermined threshold P (X ≧ P) and a constant range where X is smaller than the predetermined threshold P and greater than or equal to the threshold Q (Q ≦ X <P). There is a speed range and a deceleration range where X is smaller than the threshold value Q (X <Q). The speed range determination unit 30 determines the speed range based on the relationship between the angle difference X and the threshold values P and Q. Since the rotation angle of the rotor 12 and the count number correspond one-to-one, each value of X, P, and Q may be replaced with the count number.

  Note that the speed range may be determined by detecting angular acceleration related to the rotation of the motor 10. If the angular acceleration of the rotor 12 is positive and the rotation of the rotor 12 is accelerating, it is an acceleration region. Further, if the angular acceleration of the rotor 12 is zero and the angular velocity of the rotor 12 is substantially constant, the speed is in a constant speed range. Further, if the angular acceleration of the rotor 12 is negative and the rotation of the rotor 12 is decreasing, it is a deceleration region. Specifically, the speed region determination unit 30 determines that the acceleration region is an acceleration region when, for example, the A signal count-up or count-down interval is shortened according to time. Further, when the count-up or down interval is constant, it is determined that the speed is in the constant speed range. Further, when the count-up or down interval becomes longer according to time, it is determined that the vehicle is in the deceleration range.

  An encoder signal output from the encoder 20 can be used to detect the current position of the rotor 12 and the angular acceleration. The speed range determination unit 30 determines which speed range the rotor 12 is in, and outputs information indicating the speed range to the control unit 40.

  The control unit 40 is, for example, a shift-by-wire ECU. The control unit 40 controls the inverter that constitutes the drive circuit 50. The drive circuit 50 allows current to flow through the energized phases of the U phase, the V phase, and the W phase based on instructions from the control unit 40. The control unit 40 calculates the rotation speed of the rotor 12 based on the encoder signal output from the encoder 20. The control unit 40 determines an energized phase to be energized based on the speed range and the rotational speed of the rotor 12 input by the speed range determination unit 30. When the phase lead correction is not taken into account, energization is performed in the order of U phase → UV phase → V phase → VW phase → W phase → WU phase → U phase. 12 rotates 45 degrees. In addition, the control unit 40 in the present embodiment can control the drive circuit so that the off timing of energization to the energized phase is delayed from the original off timing. Details of the control by the control unit 40 will be described later.

  The drive circuit 50 is a generally known three-phase drive inverter circuit. The drive circuit 50 has three pairs of inverter circuits (not shown), and each inverter circuit supplies current to each of the U-phase, V-phase, and W-phase energized phases based on instructions from the control unit 40.

  Next, control of the electronic control apparatus 100 according to the present embodiment will be described with reference to FIGS. Note that the flow shown in FIG. 4 is executed when the encoder signal changes, and the flow until the controller 40 outputs an energization instruction value for instructing which energization phase the current flows.

  As shown in FIG. 4, step S1 is first executed. Step S <b> 1 is a step in which the control unit 40 detects the rotational speed of the rotor 12. The encoder 20 outputs an encoder signal, but the mutual transition of High and Low of the encoder signal is made with a phase difference of 7.5 degrees. Since the encoder signal in this embodiment has an A signal and a B signal and the phase difference between them is 3.75 degrees, the angle difference at which the change point of the previous encoder signal and the change point of the current encoder signal are detected. Is 3.75 degrees. That is, the rotor 12 rotates 3.75 degrees while counting one edge of the encoder signal. The control unit 40 detects the angular velocity, that is, the rotational speed based on the time difference at which the change point of the previous encoder signal and the change point of the current encoder signal are detected.

  Step S2 is then executed. Step S <b> 2 is a step in which the speed range determination unit 30 determines the speed range of the rotor 12. As described above, the speed range includes an acceleration range, a constant speed range, and a deceleration range. The speed range determination unit 30 determines the speed range based on the angle difference X between the rotation angle of the current position of the rotor 12 and the rotation angle of the target position. The speed region determination unit 30 determines that the acceleration region is an acceleration region when the angle difference X is equal to or greater than a predetermined threshold value P (X ≧ P). Further, when X is smaller than the predetermined threshold value P and equal to or more than the threshold value Q (Q ≦ X <P), it is determined as the constant speed range. When X is smaller than the threshold value Q (X <Q), it is determined as a deceleration region.

  Step S3 is then executed. Step S3 is a step in which the control unit 40 calculates the phase advance correction amount Ks. The phase advance correction amount Ks is calculated based on the rotation speed of the rotor 12 calculated in step S1 and the speed range of the rotor 12 calculated in step S2. In order to generate torque for rotationally driving the rotor 12, it is necessary to advance the phase of the energized phase with respect to the rotational phase of the rotor 12. As the rotational speed of the rotor 12 increases after the start of driving, the changing speed of the count number of the edge of the encoder signal becomes faster, so the switching timing of the energized phase also becomes faster. When the rotational speed of the rotor 12 increases, the switching timing of the energized phase cannot follow the rotation of the rotor 12 and the drive torque may decrease. In order to solve this problem, the control unit 40 controls the energized phase to be energized beforehand in advance of the rotational phase of the rotor 12 according to the rotational speed and speed range of the rotor 12. The amount to be preceded depends on the rotation speed and speed range. This preceding amount is the phase advance correction amount Ks. The phase advance correction amount Ks corresponds to an angle with 7.5 degrees as a unit, but may be converted into a count number in the present embodiment.

  The phase advance correction amount Ks increases as the rotational speed of the rotor 12 increases. Further, the control unit 40 controls the phase advance correction amount Ks so as to increase with time if the rotor 12 is in the acceleration region. On the other hand, when the rotor 12 is in the deceleration region, control is performed so as to decrease the phase advance correction amount Ks. The calculation of the phase advance correction amount Ks is detailed in Japanese Patent Application Laid-Open No. 2004-23931.

  Step S4 is then executed. Step S4 is a step in which the controller 40 determines an energized phase to be energized. The controller 40 determines the energized phase based on the current position N (count number) of the rotor 12, the phase advance correction amount Ks (count number), and the conversion table shown in FIG. When the energization to the energized phase in this embodiment is made a cycle such as U phase → UV phase → V phase → VW phase → W phase → WU phase, the count number increases or decreases by 12. Therefore, the remainder obtained by dividing the sum M (= D + Ks) of the current position N and the phase advance correction amount Ks by 12 is a factor for determining the energized phase. In FIG. 5, this remainder is described as M mod12.

In addition, the energization phase determined in step S4 is calculated as an energization instruction value (U _i , V _i , W _i ). The energization instruction value becomes 1 when the corresponding energization phase is energized, and becomes 0 when the energization is not energized. For example, if M mod 12 = 3, (U _i , V _i , W _i ) = (0, 0, 1). In another example, if M mod 12 = 8, (U _i , V _i , W _i ) = (1, 1, ₀ ).

  Step S5 is then executed. Step S5 is a step in which the controller 40 determines whether or not the speed range of the rotor 12 is a deceleration range. Based on the speed range information input from the speed range determination unit 30, the control unit 40 determines YES if the rotor 12 is in the deceleration range, and determines NO if the rotor 12 is in the acceleration range or the constant speed range.

  If YES is determined in step S5, that is, if the rotor 12 is in the deceleration region, the process proceeds to step S6.

  Step S6 is a step in which the controller 40 calculates an energized phase that delays the energization off timing. When the off timing is not delayed, the off timing is synchronized with the edge of the encoder signal. Therefore, delaying the off timing means that the phase related to the off timing of energization to the energized phase is delayed with respect to the change point (edge) of the encoder signal. It means to be compatible.

The control unit 40 refers to the previous energized phase before switching and the current energized phase calculated in step S4 and determines the energized phase to delay the phase in which the indicated value has changed as 1 → 0. For example, it is assumed that the previous energized phases are the U phase and the V phase. That is, it is assumed that (U _i−1 , V _i−1 , W _i−1 ) = ( ₁ , ₁ , ₀ ). The current energized phase calculated in step S4 is assumed to be the V phase. That is, (U _i , V _i , W _i ) = (0, 1, 0). Since the energized phase whose instruction value has changed from 1 to 0 is the U phase, the control unit 40 selects the U phase as the energized phase that delays the off timing of energization.

  Step S7 is then executed. Step S7 is a step in which the control unit 40 calculates the delay time of the off timing in the energized phase calculated in step S6. In other words, this is a step of calculating the amount of delay with respect to the edge of the encoder signal at the off timing in the energized phase that is delayed. Since the encoder signal depends on the rotation speed of the rotor 12, the delay time referred to here can be converted through the rotation speed of the rotor 12, and is synonymous with the amount of delay phase.

  The delay time (delay amount) will be described with reference to FIG. FIG. 6 is a timing chart showing the A signal and B signal, which are encoder signals, the indicated values of each energized phase, and the time variation of the current flowing through each energized phase. A solid line shows a chart after delaying the off timing, and a broken line shows a chart in the conventional control in which the delay phase is not performed. In order to simplify the explanation, FIG. 6 shows an example in which the phase advance correction amount is not applied.

  Following the example in step S6, it is assumed that the previous energized phase is the U phase and the V phase, and the current energized phase is the V phase. The energized phase whose energization off timing is delayed is the U phase. At this time, as shown in FIG. 6, the start of the fall of the current flowing in the U phase is delayed with the delay of the U phase energization instruction value. Thereby, before the current flowing in the U phase becomes zero, energization of the W phase, which is the energized phase that is turned on for the first time, is started and the current begins to flow. That is, the interval between the fall of the current related to turning off the U-phase energization and the rise of the current related to energization of the W-phase that is turned on for the first time after the U-phase off timing is narrowed. Alternatively, the fall of the U phase and the rise of the W phase overlap. In other words, the delay amount is such that the interval between the fall of the current related to turning off the energization and the rise of the current related to turning on of another energized phase that is turned on for the first time after the off timing is narrowed or overlapped. Is set as follows.

  For this reason, the amount of delay phase depends on the slew rate at the fall of the current and the current value at the start of the fall. Here, the slew rate of the current depends on the reactance and resistance value of the winding 13 wound around the salient pole 11 a of the stator 11. The value of the current at the start of falling depends on the power supply voltage that supplies current to the winding 13. Therefore, as a delay amount, a reference delay amount θ serving as a reference is set in advance under the conditions of the reactance and resistance value of the winding 13 serving as a reference and the power supply voltage serving as a reference. That is, the delay time (delay amount) calculated in step S7 corresponds to the reference delay amount θ under the conditions of the reactance and resistance value of the reference winding 13 and the reference power supply voltage. Under this condition, it is possible to narrow or overlap the interval between the fall of the current related to turning off energization and the rise of the current related to turning on of another energized phase that is turned on for the first time after the off timing.

  Hereinafter, an example will be described in which the control unit 40 performs control so as to overlap the falling of the current related to turning off energization and the rising of the current related to turning on of another energized phase that is turned on for the first time after the off timing.

  As described above, the current slew rate depends on the reactance and the resistance value of the winding 13, and the time until the current becomes zero depends on the power supply voltage. For this reason, it is preferable to introduce a correction amount δθ of the slow phase amount in step S7.

  The slew rate increases as the temperature of the winding wire 13 and the motor 10 increases, and the time until the current becomes zero becomes shorter. Therefore, the control unit 40 sets a large amount of delay with δθ> 0 under the condition that the temperature of the motor 10 is higher than the reference temperature. Thereby, before the current related to turning off energization becomes zero, the current related to turning on another energized phase that is turned on for the first time after the off timing rises, so that both can be overlapped.

  Further, the time until the current flowing through the winding 13 becomes zero becomes shorter as the power supply voltage becomes smaller. Therefore, the control unit 40 sets a large amount of delay with δθ> 0 under the condition that the power supply voltage is lower than the reference power supply voltage. Thereby, before the current related to turning off energization becomes zero, the current related to turning on another energized phase that is turned on for the first time after the off timing rises, so that both can be overlapped.

  Furthermore, it is preferable to set an upper limit on the amount of delay so that the energization-off timing delayed with respect to the encoder signal change point is set before the next change point of the encoder signal. This is because the energization pattern may collapse and step out when the delayed energization off timing exceeds the next change point of the encoder signal. In the present embodiment, the control unit 40 preferably sets δθ so as to satisfy θ + δθ <3.75 °. Since the change in the encoder signal depends on the rotation speed of the rotor 12, the amount of delay phase can be restated as a delay time. That is, it is preferable that the control unit 40 sets the delay time of the off timing so that the energization instruction value becomes 0 before the rotor 12 rotates 3.75 degrees.

  Next, step S8 is executed. Step S8 is a step in which the control unit 40 sets a delay timer by a generally known timer circuit provided in the control unit 40 based on the delay time calculated in step S7. Until the delay timer expires, the energization of the energized phase whose instruction value has changed from 1 to 0 is continued. In the above example, energization of the U phase is continued.

Step S9 is then executed. Step S9 is a step in which the control unit 40 calculates and outputs energization instruction values (U _j , V _j , W _j ) in consideration of the delay timing of the off timing. The energization instruction value considering the slow phase is the logical sum of the previous energization instruction value (U _i−1 , V _i−1 , W _i−1 ) and the current energization instruction value (U _i , V _i , W _i ). It becomes. That is, (U _j , V _j , W _j ) = (U _i−1 | U _i , | V _i−1 | V _i , | W _i−1 | W _i ). In the above example, (U _i−1 , V _i−1 , W _i−1 ) = ( ₁ , ₁ , 0) and (U _i , V _i , W _i ) = (0, 1, 0) Therefore, (U _j , V _j , W _j ) = (1, 1, 0). In this example, the previous energization instruction value is substantially continuously output. Note that the energization instruction value calculated in step S9 is valid until the delay timer expires.

Thus, when the rotor 12 is in the deceleration region, the energization instruction values (U _j , V _j , W _j ) taking into account the slow phase are output from the control unit 40 and the drive circuit 50 is based on the energization instruction values. Drive.

On the other hand, if the rotor 12 is in the acceleration region or the constant speed region in step S5, the determination is NO. If NO is determined in step S5, step S10 is executed as shown in FIG. Step S10 is a step in which the control unit 40 outputs the current energization instruction values (U _i , V _i , W _i ) calculated in step S4. Then, the drive circuit 50 is driven based on the energization instruction value. That is, the energized phase is switched without delaying the off timing.

When the delay timer set in step S8 expires, the control unit 40 outputs an energization instruction value according to the flow shown in FIG. That is, step S11 is executed. Step S11 is a step in which the control unit 40 outputs the current energization instruction value (U _i , V _i , W _i ) calculated in step S4. Then, the drive circuit 50 is driven based on the energization instruction value. That is, on the condition that the delay timer has expired, the off-phase delay phase ends, and energization to the target energized phase is executed.

  Next, the effect by employ | adopting the electronic control apparatus 100 which concerns on this embodiment is demonstrated.

  For example, it is assumed that the energized phase transitions in the order of UV phase → V phase → VW phase. When shifting from the UV-phase energization state to the V-phase energization, the U-phase energization is turned off and the attractive force due to the U-phase energization disappears, so that the salient pole 12a of the rotor 12 is attracted by the attractive force due to the V-phase energization. Gravitate. Thereby, the rotor 12 rotates. In the present embodiment, when the rotation of the rotor 12 is in the deceleration region, the OFF timing of the U-phase energization is delayed as compared with the conventional switching of the energized phase. Therefore, as shown in FIG. The attractive force remains even when the attractive force disappears. For this reason, the angular acceleration of the rotor 12 concerning deceleration can be enlarged.

  In particular, in the present embodiment, the current due to the U-phase energization overlaps with the rise of the W-phase current that is energized next time, and therefore the attractive force due to the U-phase energization remains even during the energization period of only the V-phase. . Accordingly, it is possible to continue to apply a force directed to the direction opposite to the rotation direction to the rotor 12 even during the V-phase energization. For this reason, time until rotation of the rotor 12 stops can be shortened.

  The conventional method of driving the rotor 12 by introducing the phase advance correction amount can shorten the time to reach the constant speed region in the acceleration region of the rotor 12 and improve the responsiveness of the driver to the range switching operation. Realized that. On the other hand, in the deceleration region, there was no other way than to decelerate with the phase advance correction amount almost eliminated. On the other hand, the electronic control unit 100 according to the present embodiment can retain the attractive force by delaying the off timing of energization to the energized phase, and therefore, as shown in FIG. It is possible to reduce the time required for the realization. That is, the responsiveness to the driver's operation can be improved.

  In this embodiment, an example has been described in which the falling of the current related to turning off energization overlaps the rising of the current related to turning on of another energized phase that is turned on for the first time after the off timing. You don't have to. If the falling of the current related to turning off the current is delayed as compared with the conventional control, a force in the direction opposite to the rotation direction of the rotor 12 acts, so that the angular acceleration of the rotor 12 for deceleration is increased. Can do.

(Second Embodiment)
When the energization phase is turned off, that is, when the energization instruction value changes from 1 to 0, the energization instruction value is PWM controlled to accurately determine the slew rate related to the fall of the current flowing in the energization phase. Can be controlled. Elements constituting the electronic control device 100 are the same as those in the first embodiment, and controls such as calculation of the number of rotations of the rotor 12, determination of the speed range, calculation of energized phase that delays off timing, and the like are performed in the first embodiment. Therefore, the detailed description is omitted. The control unit 40 in the present embodiment outputs the energization instruction value in the energization phase that delays the off timing by a method different from that in the first embodiment.

  As shown in FIG. 10, the control unit 40 in the present embodiment is configured to output the energization instruction value by PWM control during a period in which the delay timer is valid. FIG. 10 shows how the U-phase off timing is delayed when the UV phase energization state transitions to the V phase energization state. In the graph regarding the current of the energized phase, the solid line indicates the behavior of the current in the present embodiment, and the broken line indicates the behavior of the current in the first embodiment. As described in the first embodiment, the state in which the off timing of the U phase is delayed is a period in which the delay timer set in step S8 in FIG. 4 is valid. In the present embodiment, the control unit 40 performs PWM control of the energization instruction value during the entire period or a part of the period during which the delay timer is valid. In FIG. 10, the W-phase energization instruction value is PWM-controlled during the W-phase delay period during U-phase energization. In addition, the U-phase energization instruction value is PWM-controlled during the U-phase delay period during V-phase energization.

  According to this, it is possible to control the slew rate related to the fall of the current with higher accuracy than in the case where the energization instruction value is changed as 1 → 0 without using the PWM control. This is synonymous with controlling the attractive force acting in the direction that prevents the rotation of the rotor 12 with high accuracy, so that the stop position of the rotor 12 and the time in the deceleration region required for stopping can be controlled with high accuracy.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In each of the above embodiments, the number of salient poles 11a in the stator 11 is 12 and the number of salient poles 12a in the rotor 12 is 8. However, it goes without saying that the number of salient poles can be arbitrarily set. Further, the pitch of the poles magnetized by the rotary magnet 21 in the encoder 20 is not limited to 7.5 degrees. Furthermore, although the energized phases in each of the above-described embodiments are the three phases of the U phase, the V phase, and the W phase, the number of energized phases is not limited to three.

  Further, although the example in which the rotation speed of the rotor 12 is detected based on the encoder signal is shown in step S1 described in FIG. 4, a separate rotation speed sensor may be prepared without using the encoder 20. Similarly, the determination of the speed range in step S2 may be performed by separately preparing a rotation angle sensor or the like.

  In the second embodiment, the example in which the energization instruction value is PWM controlled in a part of the period in which the delay timer is valid has been described for the period in which the PWM control is performed. The energization instruction value may be PWM controlled. In the second embodiment, the duty ratio during PWM control is not mentioned. However, if the duty ratio is reduced with the passage of time, the falling of the current applied to turn off the energized phase becomes substantially linear. Thus, the deceleration of the rotor 12 can be controlled with higher accuracy.

DESCRIPTION OF SYMBOLS 10 ... Motor, 20 ... Encoder, 30 ... Speed range determination part, 40 ... Control part, 50 ... Drive circuit, 100 ... Electronic control unit, 200 ... Shift operation part, 300 ... Engine, 400 ... Gear box

Claims (6)

A motor (10) having a rotor (12) that rotates upon energization of a plurality of energized phases;
An encoder (20) for outputting a pulsed encoder signal in synchronization with the rotation of the rotor;
A control unit (40) for controlling on / off of energization to the energized phase based on a change in the encoder signal;
A speed range determination unit (30) for determining whether the rotation of the rotor is in an acceleration range, a constant speed range, or a deceleration range,
When the rotor is in a deceleration region, the control unit delays the phase related to the off timing of energization to the energized phase with respect to the rotation direction of the rotor by delaying the phase with respect to the change point of the encoder signal. Electronic control device that controls the force to work in the opposite direction. The control unit delays the phase related to the off timing of energization to the energized phase with respect to the change point of the encoder signal,
2. The electronic control unit according to claim 1, wherein control is performed so that a fall of a current related to energization off and a rise of a current related to on of another energized phase that is turned on for the first time after the off timing overlap each other.   3. The electronic control device according to claim 1, wherein the control unit performs PWM control of energization at the off timing to control a current amount at a falling edge of a current flowing in the energization phase.   4. The electronic control device according to claim 1, wherein the energization-off timing delayed in phase with respect to the change point of the encoder signal is set before the next change point of the encoder signal.   5. The electron according to claim 1, wherein the control unit increases a delay amount of the off timing with respect to a change point of the encoder signal as a power supply voltage related to energization to the energized phase is smaller. Control device.   6. The electronic control device according to claim 1, wherein the control unit increases a delay amount of the off timing with respect to a change point of the encoder signal as the temperature of the motor is higher.

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