JP2014103809A - Motor Drive system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive system capable of performing electrification control at least equal to the prior arts by using magnetic detection elements less than the prior arts.SOLUTION: The motor drive system comprises a permanent magnet 3 for torque generation which is magnetized to (p) poles (p=2, 4, ...); and a permanent magnet 4 for position detection which is magnetized to 3p poles. A magnetic field by the permanent magnet 4 is detected by a single magnetic detection element 5 and a detection signal is outputted. An edge counter 6 counts the number of rising/falling edges which appear in the detection signal. Before starting a commutation, a rotor 1r is positioned in an initial location, and a count value of the edge counter 6 is initialized. After the commutation is started, the commutation is performed in accordance with a predetermined electrification pattern corresponding to the count value.

Description

  The present invention relates to a motor drive system that drives a motor having a rotor with a permanent magnet for generating torque.

  A DC brushless motor having a permanent magnet in the rotor has features such that it can be reduced in size as compared with a DC motor having a brush and has high durability. In order to drive a DC brushless motor (hereinafter referred to as a motor), detection of the magnetic pole position of the rotor is indispensable. In general, three magnetic detection elements such as Hall ICs are arranged on the stator side at an interval of 120 ° (electrical angle) so as to face a permanent magnet for generating torque, and a position signal output from the Hall IC. Based on this, the rotational position is detected every 60 °.

  In this configuration, the leakage magnetic flux of the permanent magnet is detected, so there are structural limitations such as the need to place the Hall IC as close as possible to the permanent magnet. When actually designing and manufacturing the motor, It was sometimes difficult to realize. Therefore, Patent Document 1 employs a motor including a position detecting permanent magnet having the same number of magnetic poles as the permanent magnet coaxially with the torque generating permanent magnet. Since the permanent magnets for position detection are also arranged at intervals of 120 °, the position every 60 ° can be detected based on the position signal output from the Hall IC as described above.

  In recent years, sensorless control for detecting the magnetic pole position of the rotor by directly or indirectly detecting the speed electromotive force of the motor without using a magnetic detection element such as a Hall IC is also used. However, the sensorless control cannot detect the position at the time of stopping and at a low speed, and has a disadvantage that a microcomputer having high processing capability is required because the load on the microcomputer becomes large.

JP 2005-229688 A

  When a motor including a permanent magnet for position detection in addition to a permanent magnet for generating torque is used, the degree of freedom in disposing the magnetic detection element increases. However, three magnetic detection elements are still required, and a position detection means with a simpler configuration is desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a motor drive system capable of performing at least an energization control equivalent to that in the past by using a smaller number of magnetic detection elements than in the past. is there.

  In the motor drive system according to claim 1, a three-phase winding is wound around the stator, a permanent magnet for generating torque of p poles (p = 2, 4, 6,...) And 3p with an equal angular width are provided on the rotor. A motor having a permanent magnet for position detection magnetized on the pole is driven. The energizing means energizes the windings of the motor. The position detection means has a first magnetic detection element (Hall IC), detects a magnetic field generated by a permanent magnet for position detection, and outputs a first detection signal composed of an H level and an L level. The counter counts the number of rising edges and falling edges that appear in the first detection signal. Before starting commutation, the energizing means energizes a predetermined phase of the winding to position the rotor at the initial position and initializes the count value of the counter. After commutation is started, the motor is driven by controlling energization of the windings according to a predetermined energization pattern corresponding to the count value of the counter.

According to this configuration, since the rotational position of the rotor can be detected by the counter value, it is possible to perform energization control equivalent to the conventional one using one magnetic detection element that is smaller than the conventional one.
According to the motor drive system of the second aspect, the position detection means is arranged with an angle difference corresponding to 30 ° (electrical angle) of the permanent magnet for generating torque with respect to the first magnetic detection element. The magnetic detection element is provided. The second magnetic detection element detects a magnetic field generated by the position detecting permanent magnet and outputs a second detection signal. The counter counts the number of rising edges and falling edges that appear in the first and second detection signals.

  According to this configuration, the rotational position of the rotor can be detected with double accuracy. Accordingly, it is possible to realize control with higher accuracy than the conventional 120 ° energization control using two magnetic detection elements fewer than the conventional one, and to reduce torque ripple and noise.

  According to the motor drive system described in claim 3, the counter separately determines the number of rising edges and falling edges that appear in the first detection signal, and the number of rising edges and falling edges that appear in the second detection signal. To count. And a control means determines the presence or absence of the failure of a 1st and 2nd magnetic detection element based on the relationship between the count value of a 1st detection signal, and the count value of a 2nd detection signal. When any of the magnetic detection elements is determined to be normal, energization to the winding is controlled based on the count value of the first detection signal and the count value of the second detection signal. When it is determined that the first magnetic detection element has failed, energization to the winding is controlled based on the count value of the second detection signal. When it is determined that the second magnetic detection element has failed, energization to the winding is controlled based on the count value of the first detection signal.

  According to this configuration, even if one of the two magnetic detection elements fails, the motor can be driven based on the detection signal detected by the other magnetic detection element, so that the fault tolerance is improved.

According to the motor drive system described in claim 4, after starting commutation, the control means determines the rotation direction of the rotor based on the phase difference between the first and second detection signals.
According to this configuration, it is possible to detect when the rotor starts rotating in reverse due to the rotational position of the rotor deviating from a predetermined initial position at the start of commutation.

The block diagram of the motor drive system which shows the 1st Embodiment of this invention The perspective view which shows typically the rotor provided with the permanent magnet for torque generation, and the permanent magnet for position detection Explanatory drawing showing the positional relationship between magnetic poles and windings for a 2-pole motor Motor drive control signal correspondence table Motor drive control flowchart FIG. 3 equivalent view in the second embodiment of the present invention. 4 equivalent diagram Figure equivalent to FIG. FIG. 3 equivalent diagram in the third embodiment of the present invention 4 equivalent diagram Figure equivalent to FIG. FIG. 3 equivalent diagram in the fourth embodiment of the present invention 4 equivalent diagram Magnetic sensor output level signal correspondence table Figure equivalent to FIG. FIG. 5 equivalent diagram in the fifth embodiment of the present invention

In each embodiment, substantially the same parts are denoted by the same reference numerals and description thereof is omitted. The angle used in the description is an angle based on the electrical angle of the permanent magnet for generating torque.
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The motor 1 used in this embodiment is driven by a three-phase 120 ° energization method. In the motor 1, a three-phase winding is wound around a stator 1s, and a permanent magnet 3 for generating torque of p poles (p = 2, 4, 6,...) Is attached to the surface of the rotor yoke 2 of the rotor 1r. This is a SPM (Surface Permanent Magnet) DC brushless motor. 1 and 2 show the case where p = 4.

  A permanent magnet 4 for position detection formed in a disk shape is fitted to the rotating shaft in the vicinity of the axial end face of the rotor yoke 2. The permanent magnet 4 is magnetized with an equiangular width on 12 poles, which is three times the number of magnetic poles p of the permanent magnet 3. In the stator 1s, a single magnetic detection element 5 (position detection means) is installed at a position facing the magnetic pole portion of the permanent magnet 4. The magnetic detection element 5 detects a magnetic field generated by the permanent magnet 4, and outputs a first detection signal that is inverted between the H level and the L level at 60 ° intervals when the rotor 1r rotates. As the magnetic detection element 5, for example, a Hall IC is used.

  The edge counter 6 receives a detection signal from the magnetic detection element 5 and counts the number of rising edges and falling edges of the rectangular wave of this detection signal. The edge counter 6 is a ring counter that sequentially counts from 0 to 5 and returns to 0 again.

  The microcomputer 7 (control means for controlling energization of the winding) receives the count signal from the edge counter 6 and outputs drive signals Up, Vp, Wp, Un, Vn, Wn in the three-phase 120 ° energization method. . The energization patterns of the drive signals Up, Vp, Wp, Un, Vn, Wn will be described later.

  The inverter circuit 8 (energizing means) includes six transistors (semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors)) 9a to 9f between power lines 11a and 11b to which a DC power source 12 such as an in-vehicle battery is connected. It has a configuration with a three-phase bridge connection. Freewheeling diodes 10a to 10f are connected between the collectors and emitters of the transistors 9a to 9f. Drive signals Up, Vp, Wp, Un, Vn, and Wn are input from the microcomputer 7 to the transistors 9a to 9f, respectively. U-phase, V-phase, and W-phase drive windings 13u, 13v, and 13w are connected to the connection points (output terminals) of the upper and lower arms of each phase of the inverter circuit 8, respectively.

  Next, a control method in the motor drive system of this embodiment will be described. In FIG. 3, the permanent magnet 3 for generating torque has two poles and the positions of the magnetic poles are simplified, and the electrical angles of the permanent magnet 3, the permanent magnet 4, the magnetic detection element 5, and the windings 13u, 13v, and 13w are shown. It is explanatory drawing which shows the positional relationship in.

  The permanent magnet 4 is magnetized to 6 poles (= 3 × 2 poles) with an equiangular width. The permanent magnet 4 has N poles 14a, 14b, and 14c and S poles 15a, 15b, and 15c, and is arranged in the order of 14a, 15a, 14b, 15b, 14c, and 15c counterclockwise. The N pole 14 a of the permanent magnet 4 is fixed so as to be in a positional relationship facing the N pole of the permanent magnet 3.

  In the stator 1s, when the U-phase winding 13u is energized in the positive direction and the V-phase winding 13v and the W-phase winding 13w are energized in the negative direction, the current flows through the inverter connection point of the U-phase winding 13u. Starting from the U-phase winding 13u, and then branching and flowing into the V-phase winding 13v and the W-phase winding 13w, the direction in which the S pole is generated is at the 0 ° position (in FIG. The position of the arrow indicating the direction of. The magnetic detection element 5 is installed corresponding to the 0 ° position of the stator 1s.

  The position of the rotor 1r shown in FIG. 3 with respect to the magnetic detection element 5 is an initial position determined by the pre-start-up energization pattern, and the N pole 14a of the permanent magnet 4 faces the magnetic detection element 5.

  FIG. 4 is a signal correspondence table showing a correspondence relationship between the output level of the detection signal of the magnetic detection element 5, the counter value in the edge counter 6, the energization pattern before activation and the energization pattern after activation. The post-start-up energization patterns a, c, e, g, i, and k correspond to counter values 0, 1, 2, 3, 4, and 5, respectively. In the energization pattern, “1” indicates that the transistor is turned on, and “0” indicates that the transistor is turned off. Here, the symbols of the energization pattern after startup are placed in alphabetical order such as a, c, e..., Because the same code is used for the same energization pattern used in the description of the other embodiments. This is for explanation.

  FIG. 5 is a flowchart showing drive control of the motor 1 executed by the microcomputer 7. The microcomputer 7 outputs the pre-start-up energization pattern init for a predetermined time, for example, 1 second before starting, that is, before starting commutation (S101, S102). The pre-start energization pattern init is a drive signal (Up, Vp, Wp, Un, Vn, Wn) = (1, 0, 0, 0, 1, 1). This energization generates a magnetic flux in the direction of Finit in FIG. 3, and the S pole of the permanent magnet 3 for generating torque is positioned in the Finit direction.

  Next, the counter value of the edge counter 6 is initialized to “0” (S103). Then, it starts and commutation is started (S104). The initial energization pattern a (0, 0, 1, 0, 1, 0) causes the direction of Fa that causes the magnetic flux of the stator 1s to generate the maximum torque with respect to the permanent magnet 3 at the initial position. Start rotating in the CW direction. Until the edge counter 6 counts up, it continues to output the energization pattern a after startup (S105, S106).

  When the rotor 1r rotates 30 ° from the initial position, the magnetic detection element 5 detects the switching of the magnetic pole from the N pole 14a to the S pole 15a of the permanent magnet 4, so that the detection signal output by the magnetic detection element 5 is L level. Changes from H to H level. With this rising edge, the counter value of the edge counter 6 is incremented from “0” to “1” (S105), and the microcomputer 7 receives the input of this counter value and starts energization pattern c (0, 0, 1,. 1, 0, 0) is output (S107). Thereby, the magnetic flux of the stator 1s becomes the direction of Fc, and the rotor 1r rotates in the CW direction.

  Next, when the rotor 1r further rotates by 60 °, the magnetic detection element 5 detects the switching of the magnetic pole from the S pole 15a to the N pole 14b of the permanent magnet 4, so that the detection signal output by the magnetic detection element 5 is H It changes from level to L level. Due to the falling edge of this detection signal, the counter value of the edge counter 6 is incremented from “1” to “2” (S105), and the microcomputer 7 receives the input of this counter value and starts energization pattern e (0, 1, 0, 1, 0, 0) is output (S108). Thereby, the magnetic flux of the stator 1s becomes the direction of Fe, and the rotor 1r rotates in the CW direction.

  When the rotation further proceeds and the magnetic pole of the permanent magnet 4 facing the magnetic detection element 5 changes between the N pole and the S pole, a falling edge and a rising edge appear alternately at 60 ° intervals in the detection signal. The counter value is incremented by 1 (S105). Accordingly, the microcomputer 7 sequentially switches the energization pattern after startup to g, i, k... (S109, S110, S111) as shown in FIG. 4 so that the direction of the magnetic flux of the stator 1s is Fg, Fi, Fk. And switch.

  The above commutation control is continued unless a stop signal is given in S112, and the motor 1 continues to rotate. When a stop signal is given in S112, stop processing is performed to turn off all the transistors or turn on the upper arm or lower arm transistors of each phase (S113).

  As described above, according to the present embodiment, the position of the rotor 1r can be detected by using one magnetic detection element 5 that is smaller than the conventional one, and the motor of the three-phase 120 ° energization method equivalent to the conventional one is used. Can be controlled.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. The motor drive system in the second embodiment uses two magnetic detection elements. The first magnetic detection element 5a is arranged at the same position as the magnetic detection element shown in FIG. The second magnetic detection element 5b is arranged at a position in the CCW direction with an angle difference corresponding to 30 ° with respect to the magnetic detection element 5a when viewed from the electrical angle of the permanent magnet 3 for torque generation. The magnetic detection elements 5a and 5b output detection signals Ha and Hb, respectively. The detection signals Ha and Hb are input to the edge counter 6. Other configurations are the same as those of the first embodiment.

  By adopting the above configuration, when the motor 1 is rotating in the CW direction, the detection signal Ha has a relationship delayed by 30 ° with respect to the detection signal Hb, and the detection signals Ha and Hb are spaced at intervals of 30 °. Rising and falling edges appear. The edge counter 6 counts the number of rising edges and falling edges of these detection signals Ha and Hb. Therefore, the edge counter 6 counts the number of edges at 60 ° intervals in the first embodiment, whereas the edge counter 6 counts the number of edges at 30 ° intervals in the present embodiment. The edge counter 6 is a ring counter that sequentially counts from 0 to 11 and returns to 0 again.

  FIG. 7 is a signal correspondence table showing the correspondence between the output levels of the detection signals Ha and Hb of the magnetic detection elements 5a and 5b, the counter value of the edge counter 6, the energization pattern before activation, and the energization pattern after activation. FIG. 8 is a flowchart showing drive control of the motor 1 executed by the microcomputer 7.

  First, before the microcomputer 7 starts commutation, the pre-start energization pattern init is output, the rotor 1r is positioned at the initial position, and the edge counter 6 is initialized to the counter value “0” until the first counter 1 is initialized. The same as the embodiment (S201 to S203). Thereafter, commutation is started (S204). The post-start-up energization patterns a to l correspond to the counter values 0 to 11 of the edge counter 6. The energization patterns a, c, e, g, i, and k having the same reference numerals as those in the first embodiment indicate the same energization patterns as in the first embodiment.

  When the pre-start energization pattern init is output to position the torque generating permanent magnet 3 at the initial position, the magnetic detection element 5b is near the boundary between the N pole 14a and the S pole 15a of the position detecting permanent magnet 4. Exists. Therefore, there is a concern that the magnetic detection element 5b detects the switching of the magnetic poles of the N pole 14a and the S pole 15a and outputs an unintended detection signal Hb due to a slight movement of the rotor 1r during the positioning operation. As for this, during the operation of positioning the permanent magnet 3 for generating torque at the initial position, the detection signal Hb is masked to prevent the edge counter 6 from counting up due to the unintended detection signal Hb.

  The first energization pattern a after start-up is (0, 0, 1, 0, 1, 0), whereby the magnetic flux of the stator 1s becomes the direction of Fa that generates the maximum torque with respect to the initial position, and the rotor 1r , Start rotating in the CW direction. Until the edge counter 6 counts up, it continues to output the energization pattern a after startup (S205, S206).

  When the rotor 1r rotates 30 ° from the initial position, the magnetic detection element 5a detects the change of the magnetic pole of the permanent magnet 4 from the N pole 14a to the S pole 15a, and the detection signal Ha changes from the L level to the H level. With this rising edge, the counter value of the edge counter 6 is incremented from “0” to “1”, and the microcomputer 7 outputs the energization pattern b (0, 0, 1, 1, 1, 0) after startup (S207). ). As a result, the magnetic flux of the stator 1s becomes the direction of Fb advanced by 30 ° in the CW direction, and the rotor 1r rotates in the CW direction. During this time, since the magnetic detection element 5b continues to detect the S pole 15a, the level of the detection signal Hb does not change.

  When the rotor 1r further rotates by 30 ° and then by 60 ° from the initial position, the magnetic detection element 5b detects the switching of the magnetic pole from the S pole 15a to the N pole 14b of the permanent magnet 4, so that the magnetic detection element 5b outputs The detection signal Ha to be changed changes from the H level to the L level. Due to this falling edge, the counter value of the edge counter 6 is incremented from “1” to “2” (S205), so that the microcomputer 7 starts energization pattern c (0, 0, 1, 1, 0, 0). ) Is output (S208). As a result, the magnetic flux of the stator 1 s is in the direction of Fc further advanced by 30 ° in the CW direction, and the rotor 1 r rotates in the CW direction.

  When the rotor 1r further rotates by 30 ° and 90 ° from the initial position, the magnetic detection element 5a detects the switching of the magnetic pole from the S pole 15a to the N pole 14b of the permanent magnet 4, so that the magnetic detection element 5a outputs The detection signal Ha to be changed changes from the H level to the L level. Due to this falling edge, the counter value of the edge counter 6 is incremented from “2” to “3” (S205), and therefore the microcomputer 7 starts energization pattern d (0, 1, 1, 1, 0, 0). ) Is output (S209).

As the rotation further proceeds, edges appear alternately at 30 ° intervals in the detection signals Ha, Hb of the magnetic detection elements 5a, 5b, and the counter value increases by 1 (S205). Accordingly, as shown in FIG. 7, the microcomputer 7 sequentially switches the energization pattern after startup to e, f, g, h, i, j, k, l... (S210, S211, S212, S213, S214, S215, S216, S217), the direction of the magnetic flux of the stator 1s is switched to Fe, Ff, Fg, Fh, Fi, Fj, Fk, Fl,... At intervals of 30 ° in the CW direction.
The above commutation control continues unless a stop signal is given in S218, and the motor 1 continues to rotate. The stop process is the same as that in the first embodiment (S218, S219).

  As described above, in this embodiment, the rotational position of the rotor 1r can be detected at intervals of 30 ° by using two magnetic detection elements 5a and 5b, which are fewer than the conventional ones. By using the rotation position detection result with higher accuracy in this way, the post-start-up energization pattern that is controlled at 60 ° intervals in the first embodiment is replaced with two magnetic detection elements 5a and 5b that are smaller than the conventional ones. Therefore, since the motor drive can be controlled at intervals of 30 °, more accurate motor control can be performed, and motor control with low torque ripple and low noise can be realized.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 9 to 11. According to the present embodiment, by detecting the failure of the magnetic detection elements 5a and 5b, the rotation of the motor 1 can be continued even when one of the two magnetic detection elements fails. In the present embodiment, the detection signals Ha and Hb of the magnetic detection elements 5a and 5b are separately counted by the counters 6a and 6b, respectively. That is, the detection signal Ha is counted by the edge counter 6a, and the detection signal Hb is counted by the edge counter 6b. The counter values Ka and Kb of the edge counters 6a and 6b are input to the microcomputer 7. Other configurations are the same as those of the second embodiment.

  FIG. 10 is a signal correspondence table showing the correspondence between the detection signals Ha and Hb, the counter values Ka and Kb, the pre-start energization pattern, and the post-start energization pattern of each of the magnetic detection elements 5a and 5b. FIG. 11 is a flowchart showing motor drive control executed by the microcomputer 7.

  First, before the microcomputer 7 starts commutation, the pre-start energization pattern init is output, and the rotor 1r is positioned at the initial position (S301, 302). Next, the counter values of the edge counters 6a and 6b are initialized to “0”, and the magnetic detection element failure flag is initialized to (0, 0) (S303). Thereafter, when energization by the energization pattern a is started, the motor 1 starts to rotate in the CW direction (S304).

  In the next step S305, depending on the state of the magnetic detection element failure flag (F1, F2), S306 (when there is no failure), S330 (when the magnetic detection element 5b has failed) or S340 (magnetic detection element 5a). Branches to (if is faulty). The failure flag F1 of the magnetic detection element 5a and the failure flag F2 of the magnetic detection element 5b are set to “0” when there is no failure, and are set to “1” when there is a failure.

  When the magnetic detection element failure flag is (0, 0), that is, when there is no failure, energization is sequentially performed using a commutation pattern that switches every 30 ° as in the second embodiment (S306 to S318). The motor 1 is driven. The post-start-up energization pattern is determined from the combination of the counter values Ka and Kb. For example, when (Ka, Kb) = (0, 0), the energization pattern a (S307), when (1, 0) is the energization pattern b (S308), and when (1, 1) The energization pattern c (S309).

  When the magnetic detection element failure flag is (0, 1), that is, when the magnetic detection element 5b is defective, the energization pattern is determined by the counter value Ka based on the detection signal from the magnetic detection element 5a. That is, the motor 1 is driven by the energization patterns a, c, e, g, i, and k that are switched at intervals of 60 ° (S330 to S336).

  When the magnetic detection element failure flag is (1, 0), that is, when the magnetic detection element 5a has failed, the energization pattern is determined by the counter value Kb based on the detection signal from the magnetic detection element 5b. That is, the motor 1 is driven by the energization patterns b, d, f, h, j, and l that are switched at intervals of 60 ° (S340 to S346).

  The presence / absence of failure of the magnetic detection elements 5a and 5b is determined by the relationship between the counter values Ka and Kb of the edge counters 6a and 6b. That is, when the counter values Ka and Kb are in the relationship of Ka = Kb or Ka-1 = Kb, the magnetic detection elements 5a and 5b are operating normally. In this case, the process branches to steps S307 to S318 in step S306.

  On the other hand, if the above relationship is not established between the count values Ka and Kb and the branch condition to Steps S307 to S318 is not satisfied, it is determined that the magnetic detection element 5a or 5b has failed, and in Step S319 A magnetic detection element failure flag (F1, F2) is set.

  A failure is determined as follows. That is, when one of the magnetic detection elements 5a and 5b fails, the failed edge counter stops counting up. For example, when (Ka, Kb) = (3, 1), the count-up of the edge counter 6b is stopped, so it can be determined that the magnetic detection element 5b has failed. In this case, a magnetic detection element failure flag (0, 1) is set. For example, when (Ka, Kb) = (2, 3), the count-up of the edge counter 6a is stopped, so that it can be determined that the magnetic detection element 5a has failed. In this case, a magnetic detection element failure flag (1, 0) is set.

The above commutation control is continued unless a stop signal is given in S320, and the stop process is the same as in the first embodiment (S321).
Further, in the case where the stop process is performed after detecting the failure of the magnetic detection element (S321), the apparatus is restarted with the failure and the motor is rotated, the following control may be performed. That is, the magnetic detection element failure flag is retained even after the stop process (S321), and the magnetic detection element failure flag is not initialized in step S303 upon restart. Then, the flow of rotating the motor 1 is made using the magnetic detection element failure flag based on the failure of the magnetic detection element detected last time.

  Further, regarding the energization pattern that is positioned at the initial position at the time of restart, when the magnetic detection element 5a is out of order, the magnetic flux that generates the maximum torque for the permanent magnet 3 for torque generation positioned at the initial position is generated. The energization pattern positioned at the initial position may be changed to the energization pattern k so as to be in the direction of Fb.

  As described above, according to the present embodiment, the failure of the magnetic detection elements 5a and 6b can be detected by the combination of the counter values Ka and Kb. Even if one of the magnetic detection elements 5a and 5b breaks down, the motor drive can be continued by shifting from the motor drive control at 30 ° intervals to the motor drive control at 60 ° intervals. is there.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. As shown in FIG. 12, the motor drive system according to the present embodiment includes two magnetic detection elements 5 a and 5 b and an edge counter 6. The counter value Ka of the edge counter 6 and the detection signals Ha and Hb of the magnetic detection elements 5 a and 5 b are input to the microcomputer 7.

  FIG. 13 shows the relationship between the output levels of the detection signals Ha and Hb in normal rotation (in this embodiment, rotation in the CW direction), the counter value Ka based on the detection signal Ha, the energization pattern before activation, and the energization pattern after activation. Yes. According to the arrangement of the magnetic detection elements 5a and 5b shown in FIG. 12, the detection signal Ha has a relationship delayed by 30 ° from the detection signal Hb during normal rotation, and the detection signal Ha is detected during reverse rotation. The relationship is that the phase is advanced by 30 ° with respect to the signal Hb.

  Therefore, as shown in FIG. 13, in normal rotation, when the detection signal Ha rises, the detection signal Hb shows an H level, and when the detection signal Ha falls, the detection signal Hb shows an L level. . That is, in the case of normal rotation, the relationship of Ha = Hb is established when the detection signal Ha rises and falls, that is, when the counter value Ka is counted up.

  On the other hand, FIG. 14 shows the relationship between the detection signals Ha and Hb of the magnetic detection elements 5a and 5b in the case of reverse rotation. In the case of reverse rotation, the detection signal Hb indicates the L level when the detection signal Ha rises, and the detection signal Hb indicates the H level when the detection signal Ha falls. That is, in the case of reverse rotation, the relationship of Ha ≠ Hb is established when the detection signal Ha rises and falls, that is, when the counter value Ka is counted up.

  Thus, at the rise and fall of the detection signal Ha, it can be determined that the rotation is normal when Ha = Hb and the reverse rotation when Ha ≠ Hb. In the present embodiment, by utilizing this relationship, the count value Ka and the detection signals Ha and Hb are input to the microcomputer 7, and when the count value Ka is counted up, the detection signals Ha and Hb are compared to thereby reverse the motor 1. Detect rotation.

Next, a control flow in this embodiment will be described with reference to FIG. The processing in steps S401 to S404 is the same as that in steps S101 to S104 shown in FIG.
The rotation starts, receives the detection signal Ha from the magnetic detection element 5a, and continues to input the energization pattern a until the edge counter 6a detects an edge (S405). When the edge is detected, the detection signals Ha and Hb of the magnetic detection elements 5a and 5b are compared, and if Ha = Hb, it is determined that the rotation is normal (S406). A commutation pattern for motor drive control is output (S408 to S415).

  On the other hand, when Ha ≠ Hb, it is detected that the motor 1 is rotating in the reverse direction (S406, S407). In this case, in order to restart, the energization pattern init is energized again (S401, S402), and the rotor 1r is positioned at the initial position. The subsequent flow is as described above, and the restart process is performed until the normal rotation of the motor 1 is detected.

  Here, an example is shown in which motor drive control is performed at 60 ° intervals using the counter value Ka from the detection signal Ha from the magnetic detection element 5a, but the counter value Ka, as in the second embodiment, is shown. Motor drive control at intervals of 30 ° may be performed using Kb. When reverse rotation is detected continuously for a certain number of times, the motor drive may be stopped and an alarm may be notified.

  As described above, in the present embodiment, the reverse rotation of the motor 1 is detected using two magnetic detection elements 5a and 5b, which are fewer than the conventional one, and the normal rotation can be restored by performing the restart process. it can.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIGS. 3, 5, 6, and 16. FIG. Since the configuration of the motor drive system in the present embodiment is the same as that of the first embodiment, reference is made to FIG. FIG. 6 is referred to when referring to the direction of magnetic flux. FIG. 16 shows a processing flow in which the processing from S101 to S102 in FIG. 5 is replaced with the processing from S501 to S506, and the downward arrow in S506 leads to S103 in FIG.

  In this embodiment, motor lock is detected. First, the energization pattern init-A (1, 1, 0, 0, 0, 1) is energized for 1 second (S501, S502). By the energization pattern init-A, a magnetic flux is generated in the Fh direction in FIG. 6, and the S pole of the rotor 1r is positioned in the Fh direction. Next, the edge counter 6 is initialized to a counter value “0” (S503). Thereafter, the energization pattern init-B (1, 0, 0, 0, 1, 1) is energized for 1 second (S504, S505). Magnetic flux is generated in the Finit direction in FIG. 6 by the energization pattern init-B, and the rotor 1r rotates in the CW direction and is positioned in the Finit direction. At this time, if the rotor 1r rotates normally, the magnetic detection element 5 detects the change of the magnetic pole from the S pole 15c to the N pole 14a of the permanent magnet 4, and the edge counter 6 counts from “0” to “1”. Up. If the edge counter counts “1”, it is determined that the motor is operating normally (not locked) (S506), and the process proceeds to S103 in FIG. Motor drive control similar to that of the embodiment is performed.

On the other hand, if the count value of the edge counter 6 is “0” in S506, it is determined that the motor is locked, an error is notified (S507), and the startup process is stopped.
As described above, in the present embodiment, it is possible to detect the lock of the motor 1 by using one magnetic detection element 5 that is smaller than the conventional one, and perform error notification.

(Other embodiments)
As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and expansion | extension can be performed within the range which does not deviate from the summary of invention.

In each of the above embodiments, application to an SPM motor has been described. However, the present invention can be applied to an IPM (Interior Permanent Magnet) motor in the same manner.
As a non-contact type magnetic detection element, instead of the Hall IC, a single Hall element or a magnetoresistive element (MR element) may be used to generate a binary detection signal.

  In each of the above embodiments, a feedback system is configured using a speed control loop, a torque control loop, and the like, and the magnitude of the voltage applied to the motor windings can be controlled according to the speed deviation, torque deviation, and the like. In this case, the duty ratio may be controlled (PWM control, PDM control) by driving the upper arm transistor or the lower arm transistor on and off in a predetermined cycle during each energization period.

  The energization time for positioning by the energization patterns before startup, init, init-A, and init-B, may be sufficient to position the rotor 1r at an arbitrary position at a predetermined position, and is limited to 1 second. It is not a thing.

  In the drawings, 1 is a motor, 1s is a stator, 1r is a rotor, 3 is a permanent magnet for torque generation, 4 is a permanent magnet for position detection, 5 is a magnetic detection element, 6 is an edge counter, 7 is a microcomputer (control means) ) And 8 are inverter circuits (energizing means).

Claims (4)

The stator (1s) is wound with a three-phase winding, the rotor (1r) is a permanent magnet (3) for generating a p-pole (p = 2, 4, 6,. A motor (1) having a magnetized position detecting permanent magnet (4);
A position detection means (5) having a first magnetic detection element, for detecting a magnetic field by the position detecting permanent magnet and outputting a first detection signal composed of a first level and a second level;
Energization means (8) for energizing the windings of the motor;
A counter (6) for counting the number of rising and falling edges appearing in the first detection signal;
Before starting commutation, the energization means energizes a predetermined phase of the winding to position the rotor at an initial position and initializes the count value of the counter. A motor drive system comprising: control means (7) for controlling energization of the windings in accordance with a predetermined energization pattern corresponding to the count value of the counter after commutation is started in phase sequence. . The position detecting means is a second magnetic detecting element (5b) arranged with an angle difference corresponding to 30 ° (electrical angle) of the permanent magnet for generating torque with respect to the first magnetic detecting element (5a). And detecting a magnetic field generated by the position detecting permanent magnet and outputting a second detection signal (Hb),
The motor drive system according to claim 1, wherein the counter (6) counts the number of rising edges and falling edges that appear in the first and second detection signals (Ha, Hb). The counters (6a, 6b) determine the number of rising edges and falling edges (Ka) appearing in the first detection signal and the number of rising edges and falling edges (Kb) appearing in the second detection signal. Counting separately,
The control means determines whether or not the first and second magnetic detection elements are faulty based on a relationship between a count value of the first detection signal and a count value of the second detection signal, When it is determined that the magnetic detection element is also normal, energization to the winding is controlled based on the count value of the first detection signal and the count value of the second detection signal, and the first magnetic detection element When it is determined that the second magnetic detection element has failed, the energization to the winding is controlled based on the count value of the second detection signal. 3. The motor drive system according to claim 2, wherein energization of the winding is controlled based on a count value of the first detection signal.   The said control means determines the rotation direction of the said rotor based on the phase difference of the said 1st, 2nd detection signal after starting a commutation (S406), It is characterized by the above-mentioned. Motor drive system.

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