WO2020066946A1

WO2020066946A1 - Motor device

Info

Publication number: WO2020066946A1
Application number: PCT/JP2019/037115
Authority: WO
Inventors: 佐藤　克彦; 山口　剛
Original assignee: 日本電産株式会社; 日本電産コパル株式会社
Priority date: 2018-09-26
Filing date: 2019-09-20
Publication date: 2020-04-02
Also published as: JP2022002423A

Abstract

Provided is a motor device comprising: a motor including a rotor having magnetic poles, a stator having a multi-phase coil, and a magnetic pole sensor which detects the magnetic poles; a position detector which detects a position change of the rotor; and a motor control unit which rotates the rotor by switching an energization pattern with which the coil is energized by an AC voltage. The motor control unit, on the basis of a signal length of at least one first half cycle of a detection signal of the magnetic pole sensor, estimates a period corresponding to a unit electrical angle position which is a unit for switching the energization pattern in a second half cycle after the first half cycle, and energizes the coil with the energization pattern changed from the energization pattern that is estimated to be switched next on the basis of the detection result of the position detector, when the estimated period has elapsed.

Description

Motor device

The present invention relates to a motor device.

An example of a conventional DC brushless motor is disclosed in Patent Document 1. The DC brushless motor of Patent Document 1 includes a rotor having four magnetic poles and a stator having three-phase excitation coils. One Hall element is disposed on the stator as rotor position detecting means. The Hall element signal from the Hall element is sent to the inverter. The inverter forms a drive signal using the Hall element signal, and drives the excitation coil of each phase.

The Hall element signal detects only a magnetic pole change with respect to the excitation coil in which one Hall element is installed, and does not detect a magnetic pole change with respect to other excitation coils in which the Hall element is not installed. Therefore, the inverter includes a Hall element detecting unit, a timer unit, and an excitation pattern creating unit.

The Hall element detection means forms a Hall element detection signal by performing waveform processing on the Hall element signal. The timer means measures a period interval of the Hall element detection signal and measures a time interval during which each pole of the rotor is detected. The timer means predicts a Hall element detection signal that is not actually measured based on the measured time interval and forms the signal as a pseudo signal. The excitation pattern creating means forms an excitation pattern based on the formed pseudo signal.

Japanese Unexamined Patent Publication: JP-A-9-163787

According to Patent Literature 1, it is possible to reduce the number of Hall elements and reduce costs. However, the load on the rotor may reduce the prediction accuracy of the Hall element detection signal, that is, the accuracy of the pseudo signal. In this case, there is a possibility that normal rotation of the rotor cannot be continued because the excitation coil is driven by forming a pattern different from the excitation pattern to be originally formed.

In view of the above circumstances, an object of the present invention is to provide a motor device that can improve the control performance of a motor while reducing costs.

An exemplary motor device according to the present invention includes a motor having a rotor having magnetic poles, a stator having coils of a plurality of phases, and a magnetic pole sensor for detecting the magnetic poles, and a position detector for detecting a change in the position of the rotor. And a motor control unit that rotates the rotor by switching an energizing pattern that is energized to the coil by an AC voltage, wherein the motor control unit includes at least one first signal of a detection signal of the magnetic pole sensor. Based on a signal length in a half cycle, a period corresponding to a unit electrical angle position which is a unit for switching the energization pattern in a second half cycle after the first half cycle is estimated, and the estimated period has elapsed. Sometimes, the energization pattern, which is changed from the energization pattern estimated to be switched next based on the detection result of the position detector, is passed through the coil. Make.

According to the exemplary motor device of the present invention, it is possible to improve the control performance of the motor while reducing the cost.

FIG. 1 is a diagram illustrating a configuration of a motor device according to a first comparative example. FIG. 2 is a conceptual diagram showing an example in which the rotational position of the rotor shown in FIG. 1 is represented by an electrical angle. FIG. 3 is a timing chart illustrating drive control of the motor in the motor device according to the first comparative example. FIG. 4 is a diagram illustrating a configuration of a motor device according to a second comparative example and an exemplary embodiment of the present invention. FIG. 5 is a timing chart for explaining motor drive control in the motor device according to the exemplary embodiment of the present invention. FIG. 6 is a flowchart related to motor drive control in the motor device according to the exemplary embodiment of the present invention. FIG. 7 is a flowchart related to motor drive control in the motor device according to the exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

<1. Regarding First Comparative Example> << Before describing exemplary embodiments of the present invention, first, a comparative example for the present invention will be described. FIG. 1 is a diagram illustrating a configuration of a motor device 10 according to a first comparative example.

The motor device 10 shown in FIG. 1 includes a motor 1, an inverter 2, a motor control unit 3, a speed reducer 4, an output shaft 5, and a position detector 6. The motor device 10 further has a casing (not shown). The motor 1, the inverter 2, the motor control unit 3, the speed reducer 4, the output shaft 5, and the position detector 6 are housed in the housing. Further, the motor 1 has a U-phase terminal Tu, a V-phase terminal Tv, and a W-phase terminal Tw.

The motor 1 is configured as a DC brushless motor. The DC brushless motor is a motor that does not require a brush and a commutator by switching a current flowing through a coil by a drive circuit such as an inverter.

The motor 1 has a rotor 11, a stator 12, and Hall elements H1 to H3. The rotor 11 has, for example, four magnetic poles. Specifically, in the rotor 11, N-pole permanent magnets and S-pole permanent magnets are alternately arranged in a range of 90 degrees in the circumferential direction. The circumferential direction is a direction around the rotation axis J around which the rotor 11 rotates. Further, in the example of the present embodiment, as shown in FIG. 1, the rotation direction of the rotor 11 is counterclockwise (counterclockwise) on the paper surface of FIG.

The stator 12 includes a stator core 121, a U-phase coil 12u, a V-phase coil 12v, and a W-phase coil 12w. Stator core 121 has a core back 121A and three teeth 121B. The core back 121A has a cylindrical shape that surrounds the outside of the rotor 11 in the circumferential direction. Each tooth 121B is arranged at equal intervals in the circumferential direction. That is, the circumferential angle between adjacent teeth 121B is 120 degrees. Each tooth 121B projects radially from the inner peripheral surface of the core back 121A toward the rotor 11. The radial direction is a radial direction with respect to the rotation axis J.

The U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w are provided on each of the teeth 121B. The U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w are configured by winding a conductive wire around each tooth 121B. In the example shown in FIG. 1, one end of the U-phase coil 12u, one end of the V-phase coil 12v, and one end of the W-phase coil 12w are connected at one neutral point. The other end of U-phase coil 12u is connected to U-phase terminal Tu. The other end of V-phase coil 12v is connected to V-phase terminal Tv. The other end of W-phase coil 12w is connected to W-phase terminal Tw. That is, the U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w are connected by a so-called star connection.

A U-phase coil 12u, a V-phase coil 12v, and a W-phase coil 12w are sequentially arranged in the clockwise circumferential direction on the paper surface of FIG.

The Hall elements H1 to H3 are semiconductor sensors whose output voltage changes by magnetic force. The outputs of the Hall elements H1 to H3 are switched when the N pole and the S pole of the permanent magnet of the rotor 11 approach.

The Hall element H1, the Hall element H2, and the Hall element H3 are sequentially arranged in the clockwise circumferential direction on the paper surface of FIG. Hall element H1, hall element H2, and hall element H3 are arranged at equal intervals in the circumferential direction.

Hall element H1 is arranged at a position sandwiched between V-phase coil 12v and W-phase coil 12w in the circumferential direction. Hall element H1 is arranged at a position shifted by 60 degrees in the circumferential direction from the respective positions of V-phase coil 12v and W-phase coil 12w. Hall element H2 is arranged at a position sandwiched between W-phase coil 12w and U-phase coil 12u in the circumferential direction. Hall element H2 is arranged at a position shifted from the respective positions of W-phase coil 12w and U-phase coil 12u by 60 degrees in the circumferential direction. Hall element H3 is arranged at a position sandwiched between U-phase coil 12u and V-phase coil 12v in the circumferential direction. Hall element H3 is arranged at a position shifted by 60 degrees in the circumferential direction from the respective positions of U-phase coil 12u and V-phase coil 12v.

That is, the motor 1 includes a rotor 11 having magnetic poles, coils of multiple phases (12u, 12v, 12w), and magnetic pole sensors (Hall elements H1 to H3) for detecting magnetic poles.

The inverter 2 has a U-phase bridge 21u, a V-phase bridge 21v, a W-phase bridge 21w, and a capacitor 22. DC voltage Vcc from DC power supply 15 is applied to inverter 2. Specifically, the DC voltage Vcc is applied to one end of the capacitor 22. The other end of the capacitor 22 is connected to a ground potential. That is, one end of the capacitor 22 is on the high potential side, and the other end is on the low potential side.

The U-phase bridge 21u is configured by connecting a high-potential-side U-phase upper switching element UH and a low-potential-side U-phase lower switching element UL in series. The V-phase bridge 21v is configured by connecting a high-potential-side V-phase upper switching element VH and a low-potential-side V-phase lower switching element VL in series. The W-phase bridge 21w is configured by connecting a high-potential-side W-phase upper switching element WH and a low-potential-side W-phase lower switching element WL in series. That is, the U-phase bridge 21u, the V-phase bridge 21v, and the W-phase bridge 21w are connected in parallel to the capacitor 22.

A connection node Nu of the U-phase bridge 21u to which the U-phase upper switching element UH and the U-phase lower switching element UL are connected is connected to the U-phase terminal Tu. The connection node Nv of the V-phase bridge 21v to which the V-phase upper switching element VH and the V-phase lower switching element VL are connected is connected to the V-phase terminal Tv. A connection node Nw of the W-phase bridge 21w where the W-phase upper switching element WH and the W-phase lower switching element WL are connected is connected to the W-phase terminal Tw.

The motor control unit 3 is configured by, for example, a microprocessor or the like. The motor control unit 3 outputs the switching signals Su, Sv, Sw, Sx, Sy, and Sz to the inverter 2 to drive the inverter 2.

The U-phase upper switching element UH is switched on and off by a switching signal Su. When the switching signal Su is at a high level, the U-phase upper switching element UH is turned on, and when the switching signal Su is at a low level, the U-phase upper switching element UH is turned off.

The U-phase lower switching element UL is switched on and off by a switching signal Sx. When the switching signal Sx is at a high level, the U-phase lower switching element UL is turned on, and when the switching signal Sx is at a low level, the U-phase lower switching element UL is turned off.

The V-phase upper switching element VH is turned on and off by a switching signal Sv. When the switching signal Sv is at a high level, the V-phase upper switching element VH is turned on, and when the switching signal Sv is at a low level, the V-phase upper switching element VH is turned off.

The V-phase lower switching element VL is turned on and off by a switching signal Sy. When the switching signal Sy is at a high level, the V-phase lower switching element VL is turned on, and when the switching signal Sy is at a low level, the V-phase lower switching element VL is turned off.

The W-phase upper switching element WH is switched on and off by a switching signal Sw. When the switching signal Sw is at a high level, the W-phase upper switching element WH is turned on, and when the switching signal Sw is at a low level, the W-phase upper switching element WH is turned off.

The W-phase lower switching element WL is switched on and off by a switching signal Sz. When the switching signal Sz is at a high level, the W-phase lower switching element WL is turned on, and when the switching signal Sz is at a low level, the W-phase lower switching element WL is turned off.

When the switching signal Su is set to the high level and the switching signal Sx is set to the low level by the motor control unit 3, the U-phase upper switching element UH is turned on, the U-phase lower switching element UL is turned off, and the U-phase terminal Tu is A potential (DC voltage Vcc) is applied.

When the switching signal Su is set to the low level and the switching signal Sx is set to the low level by the motor control unit 3, both the U-phase upper switching element UH and the U-phase lower switching element UL are turned off, and the open potential is applied to the U-phase terminal Tu. Applied.

When the switching signal Su is set to the Low level and the switching signal Sx is set to the High level by the motor control unit 3, the U-phase upper switching element UH is turned off, the U-phase lower switching element UL is turned on, and the U-phase terminal Tu is low. A potential (ground potential) is applied.

By the switching of the switching signals Su and Sx by the motor control unit 3, the potential applied to the U-phase terminal Tu is switched, and the energization pattern of the U-phase coil 12u is switched. The U-phase coil 12u is excited according to the energization pattern.

Similarly to the U-phase described above, the switching of the pattern of the switching signals Sv and Sy by the motor control unit 3 switches the potential applied to the V-phase terminal Tv, and switches the energization pattern of the V-phase coil 12v. The V-phase coil 12v is excited according to the energization pattern.

As in the case of the above-described U-phase, by switching the patterns of the switching signals Sw and Sz by the motor control unit 3, the potential applied to the W-phase terminal Tw is switched, and the energization pattern of the W-phase coil 12w is switched. The W-phase coil 12w is excited according to the energization pattern.

Each output signal of the Hall elements H1 to H3 is output to the motor control unit 3. The motor control unit 3 has an amplifier circuit and a comparator (not shown). Each of the output signals is amplified by the amplifier circuit and is converted into a binary level Hall element detection signal by the comparator.

The motor control unit 3 controls the switching signals Su to Sz in accordance with the rotational position of the rotor 11 detected by the Hall element detection signal to control the energization pattern of the U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w. Switch. Thus, a rotational force is applied to the rotor 11 to rotate the rotor 11 around the rotation axis J.

Note that the motor 1 may include a Hall IC instead of the Hall element. The Hall IC is an IC in which the Hall element, the amplifier circuit, and the comparator are integrated on one chip.

The speed reducer 4 reduces the rotation speed of the rotor 11 and outputs the reduced speed. The speed reducer 4 has a plurality of gears. The rotor 11 has a shaft (not shown). The shaft is connected to the first gear of the speed reducer 4. The output shaft 5 is connected to the last gear of the speed reducer 4. The output shaft 5 is connected to a controlled object (not shown).

That is, the motor device 10 includes the speed reducer 4 that reduces the speed of rotation of the rotor 11 and outputs the output, and the output shaft 5 that transmits the output of the speed reducer 4 to the controlled object. Thus, for example, if the controlled object is the arm of the robot, the torque of the rotor 11 can be transmitted to the arm via the speed reducer 4 and the output shaft 5.

The position detector 6 detects the rotational position of the output shaft 5. The motor control unit 3 generates switching signals Su, Sv, and Sw based on a control signal CS input from the outside and a detection result by the position detector 6, and controls driving of the motor 1. Specifically, the duty of the switching signals Su, Sv, Sw is controlled as described later. Thus, it is possible to perform servo control for causing dynamic parameters such as the position, speed, and acceleration of the output shaft 5 to follow a target value. That is, the motor control unit 3 performs the servo control by controlling the energization of the coils (12u, 12v, 12w) based on the detection result of the position detector 6.

The position detector 6 is, for example, one of a resolver, an incremental encoder, an absolute encoder, a magnetic sensor, and a potentiometer. This makes it possible to use a position detector 6 suitable for servo control.

FIG. 2 is a conceptual diagram showing an example in which the rotational position of the rotor 11 shown in FIG. 1 is represented by an electrical angle. In FIG. 2, the rotor 11 having four poles is actually shown as two poles as shown in FIG. The counterclockwise rotation direction of the rotor 11 shown in FIG. 1 corresponds to the clockwise rotation direction of the rotor 11 in FIG. When the arrow AR along the boundary between the N pole and the S pole in the rotor 11 is used as a determination criterion, the position of the Hall element H1 is set to 0 degree in electrical angle, and the hole is shifted 120 degrees clockwise from the 0 degree position. The element H2 is located, and the Hall element H3 is located at a position further clockwise shifted by 120 degrees from the position of the Hall element H2.

Each range divided 60 degrees clockwise from the 0 degree position to 360 degrees is unit electrical angle positions P1 to P6. The relationship between the electrical angle θ _E and the mechanical angle θ _M is represented by θ _E = (P / 2) × θ _M (where P is the number of poles). , Θ _E = 2 × θ _M.

FIG. 3 is a timing chart showing drive control of the motor 1 in the motor device 10 according to the first comparative example shown in FIG. As shown in FIG. 3, the levels of the Hall element detection signals SH1 to SH3 of the Hall elements H1 to H3 are switched according to the unit electrical angle positions P1 to P6 described above.

Specifically, the Hall element detection signal SH1 is at a high level at the unitary electrical angle positions P1 to P3, and is at a low level at the unitary electrical angle positions P4 to P6. The Hall element detection signal SH2 is at a high level at the unitary electrical angle positions P3 to P5, and is at a low level at the unitary electrical angle positions P1, P2, and P6. The Hall element detection signal SH3 is at a high level at the unitary electrical angle positions P1, P5, and P6, and is at a low level at the unitary electrical angle positions P2 to P4.

Thus, the unit electrical angle positions P1 to P6 can be detected by detecting the rising edge and the falling edge of the Hall element detection signals SH1 to SH3. The motor control unit 3 detects the unit electrical angle positions P1 to P6 based on the Hall element detection signals SH1 to SH3, and generates switching signals Su to Sz corresponding to the detected unit electrical angle positions. FIG. 3 shows switching of the switching signals Su to Sz. Thereby, an appropriate rotational force can be applied to the rotor 11 according to the unit electrical angle position, and the rotation of the rotor 11 can be continued.

More specifically, for the U-phase switching signals Su and Sx, the switching signal Su is pulsed at the unit electrical angle positions P1 and P2, the Sx is at the Low level, and the switching signal Su is unitary at the unit electrical angle positions P4 and P5. Is set to the Low level, Sx is set to the High level, and at the unit electrical angle positions P3 and P6, both the switching signals Su and Sx are set to the Low level.

Regarding the V-phase switching signals Sv and Sy, the switching signal Sv is pulse-shaped and Sy is at the low level at the unitary electrical angular positions P3 to P4, and the switching signal Sv is at the low-level and Sy at the unitary electrical angular positions P1 and P6. At a high level, and at the unit electrical angle positions P2 and P5, both the switching signals Sv and Sy are at a low level.

Regarding the W-phase switching signals Sw and Sz, the switching signal Sw is set to a pulse shape and Sz is set to a low level in the unit electric angle positions P5 to P6, and the switching signal Sw is set to a low level and Sz in the unit electric angle positions P2 to P3. At a high level, and at the unit electrical angle positions P1 and P4, both the switching signals Sw and Sz are at a low level.

That is, the motor control unit 3 rotates the rotor 11 by switching the energization pattern in which the coils (12u, 12v, 12w) are energized by the AC voltage.

As described above, since the switching signal is set to the high level in the electrical angle section of 120 degrees for each phase, the driving method shown in FIG. 3 is called a 120-degree conduction method. When the switching signals Su, Sv, Sw are pulsed, the duty control by the servo control described above is reflected.

<2. Second Comparative Example> By the driving method using the Hall elements H1 to H3 shown in FIG. 3, the unit electric angle position is sequentially detected, and an appropriate driving signal is given to the motor 1, so that the driving of the motor 1 can be controlled. . However, the number of required Hall elements increases, which is disadvantageous in terms of cost.

Therefore, the motor device 10X according to the second comparative example shown in FIG. 4 is different from the motor device 10 according to the above-described first comparative example in that the motor 1X has one Hall element provided in the motor 1X. H1.

Drive control in the motor device 10X according to the second comparative example will be described with reference to FIG. In the second comparative example, the Hall element detection signals SH2 and SH3 shown in FIG. 3 are not generated. The motor control unit 3 measures a period ΔT1 from the rising timing to the falling timing of the Hall element detection signal SH1. Then, the motor control unit 3 estimates the period Δt2 corresponding to the unit electrical angle position by dividing the period ΔT1 into three equal parts.

At timing tb when the period Δt2 has elapsed from the timing ta at which the Hall element detection signal SH1 falls, the motor control unit 3 determines the pattern of the switching signals Su to Sz at the unit electrical angle position P5 which is estimated to be switched next (power supply). Pattern) and outputs it to the inverter 2. Further, at a timing tc when the period Δt2 has elapsed from the timing tb, the motor control unit 3 generates a pattern of the switching signals Su to Sz at the unit electrical angle position P6 which is estimated to be switched next and outputs the pattern to the inverter 2. I do.

In this way, the drive control of the motor 1X can be performed while reducing the cost by using one required Hall element. However, depending on the condition of the load connected to the output shaft 5, the estimated period Δt2 may deviate from the actual value. For example, when the load suddenly increases and the actual value becomes considerably larger than the estimated period Δt2, when the rotation of the rotor 11 stops due to the load, or when the rotor 11 reverses due to the load. In such a case, when the motor 1X is driven at the timing tb or tc according to the energization pattern estimated to be switched next, it is possible to apply an appropriate rotational force to the rotor 11 from the

coils

12u, 12v, and 12W of each phase. This makes it difficult to continue normal rotation of the rotor 11.

Similarly to the period ΔT1 from the rising timing to the falling timing of the Hall element detection signal SH1, the period ΔT2 from the falling timing to the rising timing of the Hall element detection signal SH1 is measured, and the period ΔT2 is divided into three equal parts. In this case, a period corresponding to the unit electrical angle position is estimated.

<3. Regarding Exemplary Embodiment of the Present Invention> An exemplary embodiment of the present invention will be described based on the first comparative example and the second comparative example described above. The configuration of the motor device according to the exemplary embodiment of the present invention is the same as that of the motor device 10X shown in FIG. That is, the cost is reduced by using the necessary Hall element as one Hall element H1. The difference from the second comparative example is the control method by the motor control unit 3. More specifically, in the present embodiment, the position detector 6 is used for drive control of the motor 1X separately from the servo control.

The rotor 11 of the motor 1X is connected to the output shaft 6 via the speed reducer 4. Thus, assuming that the reduction ratio of the speed reducer 4 is n, the rotor 11 rotates n times while the output shaft 6 makes one rotation. The position detector 6 detects a change in the position of the rotor 11.

A control method by the motor control unit 3 according to the present embodiment will be described with reference to flowcharts shown in FIGS. Note that the timing chart shown in FIG. 5 is also referred to. The detection value PD of the position detector 6 shown in FIG. 5 indicates a digital value.

When the flowchart shown in FIG. 6 is started, in step S1, when the motor control unit 3 measures the period ΔT1 from the rising timing to the falling timing of the Hall element detection signal SH1, the motor control unit 3 sets the measured period ΔT1 to 3 or the like. Then, a period Δt corresponding to the unit electrical angle position is estimated, and it is determined whether the estimated period Δt has elapsed. If the period Δt has not yet elapsed (N in step S1), the determination is continued, and if the period Δt has elapsed (Y in step S1), the process proceeds to step S2.

In step S2, the motor control unit 3 determines whether the detection value PD of the position detector 6 has changed in the normal rotation direction of the rotor 11 compared to before the lapse of Δt. The normal rotation direction is a direction in which the unit electrical angle position goes from P1 to P6. If it has changed in the forward rotation direction (Y in step S2), the process proceeds to step S3, and the motor control unit 3 changes the pattern of the switching signals Su to Sz (hereinafter, switch pattern) from the unit electrical angle position P4 to P5. Switch to business. On the other hand, if it has not changed in the normal rotation direction (N in step S2), the process proceeds to step S9 (FIG. 7) described later.

In step S4 following step S3, the motor control unit 3 determines whether the period Δt has elapsed. If the period Δt has not yet elapsed (N in step S4), the determination is continued, and if the period Δt has elapsed (Y in step S4), the process proceeds to step S5.

In step S5, the motor control unit 3 determines whether the detection value PD of the position detector 6 has changed in the forward rotation direction of the rotor 11 compared to before the lapse of Δt. If it has changed in the normal rotation direction (Y in step S5), the process proceeds to step S6, and the motor control unit 3 switches the switch pattern from the unit electrical angle position P5 to the unit electrical angle position P6. On the other hand, if it has not changed in the normal rotation direction (N in step S5), the process proceeds to step S9 described later.

After step S6, the motor control unit 3 determines whether or not the level of the Hall element detection signal SH1 has changed. That is, it is determined whether or not the level of the Hall element detection signal SH1 has risen. If there is a change (Y in step S7), the process proceeds to step S8, and the motor control unit 3 switches the switch pattern from the unit electrical angle position P6 to the unit electrical angle position P1. After step S8, the process returns to step S1.

If there is no change in the level of the Hall element detection signal SH1 (N in step S7), the process proceeds to step S9.

In step S9, the motor control unit 3 determines whether the change in the detection value PD of the position detector 6 is equal to or less than the predetermined value and there is substantially no change in the detection value, or the change in the detection value PD of the position detector 6 Is not less than or equal to the predetermined value, but indicates the reverse rotation of the rotor 11. The reverse rotation is a rotation in a direction opposite to the normal rotation direction.

If the change in the detection value PD is equal to or less than the predetermined value, there is a possibility that the rotation of the rotor 11 in the normal rotation direction is prevented by the load. This includes the case where the rotation of the rotor 11 is stopped. In this case, the process proceeds to step S10, and the motor control unit 3 maintains the switch pattern with the current switch pattern. Then, the process proceeds to step S11, and the motor control unit 3 determines whether the detection value PD of the position detector 6 has changed in the normal rotation direction of the rotor 11. If a change in the normal rotation direction has occurred (Y in step S11), the process proceeds to step S12. In step S12, it is determined whether or not the current switch pattern is for P6. If not (N in step S12), the switch pattern is switched to the current switch pattern at the next unit electrical angle position, and then step S4 is performed. Or go to S7. On the other hand, if the current switching pattern is for P6 (Y in step S12), the process proceeds to step S7.

If the detected value PD of the position detector 6 does not change in the normal rotation direction of the rotor 11 in step S11 (N in step S11), the detected value PD does not change in step S9, but the rotor 11 does not change. It may be reversed by load. Since the rotation angle of the output shaft 5 is made smaller than the rotation angle of the rotor 11 by the reduction gear 4, the rotor 11 may be rotated in the reverse direction even when the detection value PD of the position detector 6 does not change.

In this case, the process proceeds to step S13, and the motor control unit 3 returns the switching pattern to the switching pattern in which the unit electrical angle position is one before the current switching pattern. Then, after switching to the switch pattern at the current next unit electrical angle position, the process proceeds to step S1, S4, or S7.

If the change in the detected value PD of the position detector 6 indicates the reverse rotation of the rotor 11 in step S9, the process proceeds to step S13, and the motor control unit 3 determines that the unit electrical angle position is one unit smaller than the current switching pattern. Return the switching pattern to the previous switching pattern. Then, after switching to the switch pattern at the current next unit electrical angle position, the process proceeds to step S1, S4, or S7.

For example, the example shown in FIG. 5 shows a case where there is no change in the detection value PD of the position detector 6 at the timing tc when the period Δt has elapsed in step S4. In this case, the process proceeds to step S10, and the switch pattern is maintained at the current switch pattern (for P5). As a result, if the detected value PD has changed in the normal rotation direction (Y in step S11), the switch pattern is switched for P6 and the process proceeds to step S7. On the other hand, if the detected value PD does not change in the normal rotation direction (N in step S11), the switch pattern is switched to the switch pattern (for P4) whose unit electrical angle position is one before the current position (step S13). . Thereafter, the switch pattern is switched for P5 and the process proceeds to step S4.

In step S1, the motor control unit 3 measures the period ΔT2 from the falling timing to the rising timing of the Hall element detection signal SH1, and divides the measured period ΔT2 into three to obtain the unit electrical angular position. The corresponding period Δt is estimated, and it is determined whether the estimated period Δt has elapsed. In this case, the switch pattern is switched from the unit electrical angle position P1 to the unit electrical angle P2 in step S3, the switch pattern is switched from the unit electrical angle position P2 for the unit electrical angle P3 in step S6, and the switch pattern is switched to the unit electrical angle in step S8. The position is switched from P3 to P4. In step S14, it is determined whether the current switch pattern is for P3. In step S7, it is determined whether or not the level of the Hall element detection signal SH1 falls.

That is, the motor control unit 3 determines, based on the signal length (ΔT1 or ΔT2) of the detection signal SH1 of the Hall element H1 (magnetic pole sensor) in one first half cycle, in the second half cycle after the first half cycle. A period Δt corresponding to a unit electrical angle position, which is a unit for switching the energization pattern, is estimated, and when the estimated period Δt has elapsed, an energization pattern estimated to be switched next based on a detection result of the position detector 6 The coils (12u, 12v, 12w) are energized with the energization pattern changed from.

Accordingly, even when the estimated value Δt of the period corresponding to the unit electrical angle position deviates from the actual value due to the load applied to the motor 1X, the coil (12u, 12v, 12w) is appropriately energized by energizing the coil. Normal rotation of the rotor 11 can be easily continued. That is, the control performance of the motor can be improved while reducing the number of magnetic pole sensors (Hall elements) to reduce costs.

In the above embodiment, the first half cycle includes one half cycle (ΔT1 or ΔT2) immediately before the second half cycle. Thus, the period corresponding to the unit electrical angle position in the second half cycle can be estimated by a simple calculation.

In addition, when the estimated period Δt has elapsed, the motor control unit 3 maintains the current energization pattern and determines that the current energization pattern is maintained if the change in the detection value PD of the position detector 6 is equal to or smaller than a predetermined value. (12u, 12v, 12w) is energized (step S10).

Thereby, when the rotation of the rotor 11 is hindered by the load, the rotational force can be appropriately applied to the rotor 11 by exciting the coil.

When the motor control unit 3 maintains the current energization pattern and energizes the coils (12u, 12v, 12w), and determines that the change in the detection value of the position detector 6 is equal to or less than the predetermined value. Next, the coil (12u, 12v, 12w) is energized with the energization pattern whose unit electrical angle position is one before the current energization pattern (step S13).

Thus, even when the rotor 11 rotates in the reverse direction due to a large load, the torque can be appropriately applied to the rotor 11 by exciting the coil.

At this time, since the rotation angle of the output shaft 5 becomes smaller than the rotation angle of the rotor 11 due to the reduction ratio of the reduction gear 4, even when the amount of change in the detection value of the position detector 6 is smaller than a predetermined value, the rotor 11 May be in a reverse state, and an energization pattern suitable for the reverse rotation of the rotor 11 can be tried.

In addition, when the motor control unit 3 detects the reverse rotation of the rotor 11 based on the change in the detection value PD of the position detector 6 when the estimated period Δt has elapsed, the motor control unit 3 sets the unit electrical angle smaller than the current energization pattern. The coil (12u, 12v, 12w) is energized with the energization pattern one position before (step S13).

Further, according to the present embodiment, the position detector 6 used for the servo control of the output shaft 5 can be used also for the control shown in FIGS.

<4. Others> The embodiments of the present invention have been described above. However, various modifications can be made to the embodiments within the scope of the gist of the present invention.

For example, the estimation of the period Δt is not limited to one first half cycle (ΔT1 or ΔT2), and may be performed based on a plurality of first half cycles. That is, the motor control unit 3 switches the energization pattern in the second half cycle after the first half cycle based on the signal length in at least one first half cycle of the detection signal SH1 of the Hall element H1 (magnetic pole sensor). It is possible to estimate a period Δt corresponding to a unit electrical angle position as a unit.

Specifically, for example, the period Δt is estimated based on the average value or the amount of change in the signal length in a plurality of first half cycles each including at least one of ΔT1 and ΔT2. That is, the motor control unit 3 estimates the period Δt corresponding to the unit electrical angle position in the second half cycle based on the average value or the amount of change in the signal length in the plurality of first half cycles. As a result, the period Δt corresponding to the unit electrical angle position in the second half cycle can be more accurately estimated.

In addition, the present invention is not limited to the 120-degree energization method, and can be applied to overlap energization such as 150-degree energization or sine-wave energization.

INDUSTRIAL APPLICATION This invention can be utilized for the motor apparatus for robots, for example.

1, 1X motor, 11 rotor, 12 stator, 121 stator core, 121A core back, 121B teeth, 12u U phase coil, 12v・ V-phase coil, 12w ・・・ W-phase coil, 2 ・・・ Inverter, 21u ・・・ U-phase bridge, 21v ・・・ V-phase bridge, 21w ・・・ W-phase bridge, UH ・・・ U-phase upper side Switching element, VH: V-phase upper switching element, WH: W-phase upper switching element, UL: U-phase lower switching element, VL: V-phase lower switching element, WL: W Lower phase switching element, 3 ... motor controller, 4 ... reducer, 5 ... output shaft, 6 ... position detector, 10, 10X ... motor device

Claims

A motor having a rotor having magnetic poles, a stator having a multi-phase coil, a magnetic pole sensor for detecting the magnetic poles, a position detector for detecting a change in the position of the rotor; And a motor control unit that rotates the rotor by switching the energization pattern. The motor control unit is configured to control the motor control unit based on a signal length of at least one first half cycle of a detection signal of the magnetic pole sensor. Estimate a period corresponding to a unit electrical angle position, which is a unit for switching the energization pattern in a second half cycle after one half cycle, and, when the estimated period has elapsed, add a detection result of the position detector. A motor that energizes the coil with the energization pattern changed from the energization pattern that is estimated to be switched next based on the coil.
The motor device according to claim 1, wherein the first half cycle includes one half cycle immediately before the second half cycle.
The said motor control part estimates the period corresponding to the said unit electrical angle position in the said 2nd half cycle based on the average value or the amount of change of the signal length in a some said 1st half cycle. 3. The motor device according to 2.
When the estimated period has elapsed, the motor control unit determines that the change in the detection value of the position detector is equal to or less than a predetermined value, and maintains the current energization pattern to the coil. The motor device according to any one of claims 1 to 3, wherein the motor device is energized.
After maintaining the current energization pattern and energizing the coil, the motor control unit determines that a change in the detection value of the position detector is equal to or less than the predetermined value, and then determines the current energization pattern. 5. The motor device according to claim 4, wherein the coil is energized by an energization pattern whose unit electrical angle position is one position earlier than the energization pattern. 6.
A speed reducer that reduces the rotation of the rotor and outputs the output; and an output shaft that transmits the output of the speed reducer to a controlled body. The position detector detects a rotational position of the output shaft. The motor device according to any one of claims 1 to 5.
The motor device according to claim 6, wherein the motor control unit performs servo control by performing energization control to the coil based on a detection result of the position detector.
The motor device according to claim 7, wherein the position detector is one of a resolver, an incremental encoder, an absolute encoder, a magnetic sensor, and a potentiometer.
The motor control unit, when the estimated period has elapsed, when the reverse rotation of the rotor is detected based on a change in the detection value of the position detector, the unit electrical angle position is more than the current energization pattern. The motor device according to any one of claims 1 to 8, wherein the motor energizes the previous energization pattern to the coil.