JP2022002423A - Motor device - Google Patents

Abstract

To provide a motor device improved in motor controlling performance, while reducing cost.SOLUTION: A motor device 10X comprises: a motor 1X having a rotor 11 having a magnetic pole, a stator 12 having a coil with multiple phases and a magnetic pole sensor detecting the magnetic pole; a position detection device 6 detecting positional variation of the rotor 11; and a motor control unit 3 rotating the rotor 11 by switching a conduction pattern conducted to the coil by AC voltage. The motor control unit 3 estimates, on the basis of signal length in at least one first half period of a detected signal of the magnetic pole sensor, a period corresponding to a unit electric angle position being a unit for switching the conduction pattern in a second half period after the first half period. When the estimated period passes, the conduction pattern having varied from the conduction pattern estimated to be switched to the next, on the basis of the detection result of the position detection device 6, is conducted to the coil.SELECTED DRAWING: Figure 4

Description

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 a four-pole magnetic pole and a stator having a three-phase exciting coil. One Hall element is arranged on the stator as a rotor position detection 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 exciting coil of each phase.

The Hall element signal detects only the magnetic pole change for the exciting coil in which one Hall element is installed, and does not detect the magnetic pole change for the other exciting coil in which the Hall element is not installed. Therefore, the inverter has a Hall element detecting means, a timer means, and an excitation pattern creating means.

The Hall element detecting means corrugates the Hall element signal to form a Hall element detection signal. The timer means measures the cycle interval of the Hall element detection signal and measures the time interval in 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 it as a pseudo signal. The excitation pattern creating means forms an excitation pattern based on the formed pseudo signal.

Japanese Unexamined Patent Publication No. 9-163787

According to the above-mentioned Patent Document 1, the number of Hall elements can be reduced and the cost can be reduced. However, the load applied to 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 a pattern different from the originally formed excitation pattern is formed and the excitation coil is driven.

In view of the above situation, it is an object of the present invention to provide a motor device capable of improving the control performance of a motor while reducing costs.

The exemplary motor device of the present invention is
A rotor with magnetic poles and
A stator with multi-phase coils and
A magnetic pole sensor that detects the magnetic pole and
With a motor and
A position detector that detects a change in the position of the rotor, and
A motor control unit that rotates the rotor by switching the energization pattern that energizes the coil with an AC voltage.
Have,
The motor control unit is a unit for switching 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 of the magnetic pole sensor. The coil is changed from the energization pattern estimated to be switched next based on the detection result of the position detector when the period corresponding to the corner position is estimated and the estimated period elapses. Is energized.

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 showing a configuration of a motor device according to a first comparative example. FIG. 2 is a conceptual diagram showing an example in which the rotation position of the rotor shown in FIG. 1 is represented by an electric angle. FIG. 3 is a timing chart showing motor drive control in the motor device according to the first comparative example. FIG. 4 is a diagram showing 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 the drive control of the motor in the motor device according to the exemplary embodiment of the present invention. FIG. 6 is a flowchart relating to drive control of a motor in a motor device according to an exemplary embodiment of the present invention. FIG. 7 is a flowchart relating to drive control of a motor in a motor device according to an exemplary embodiment of the present invention.

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

<1. Regarding the first comparative example>
Before describing an exemplary embodiment of the present invention, first, a comparative example with respect to the present invention will be described. FIG. 1 is a diagram showing 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 includes a housing (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 the current flowing through the coil by a drive circuit such as an inverter.

The motor 1 includes a rotor 11, a stator 12, and Hall elements H1 to H3. The rotor 11 has, as an example, a four-pole magnetic pole. Specifically, in the rotor 11, the permanent magnets of the N pole and the permanent magnets of the S pole are alternately arranged in a range of 90 degrees in the circumferential direction. The circumferential direction is the direction around the rotation axis J where 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 has a stator core 121, a U-phase coil 12u, a V-phase coil 12v, and a W-phase coil 12w. The 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. The teeth 121B are arranged at equal intervals in the circumferential direction. That is, the circumferential angle between the 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 the 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 in each tooth 121B, respectively. The U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w are configured by winding a conducting 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 the U-phase coil 12u is connected to the U-phase terminal Tu. The other end of the V-phase coil 12v is connected to the V-phase terminal Tv. The other end of the W-phase coil 12w is connected to the 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 so-called star connection.

The U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w are arranged in this order in the clockwise direction on the paper surface of FIG.

The Hall elements H1 to H3 are semiconductor sensors whose output voltage changes depending on the magnetic force. The Hall elements H1 to H3 switch their outputs when the north and south poles of the permanent magnets of the rotor 11 approach each other.

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

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

That is, the motor 1 has a rotor 11 having a magnetic pole, a multi-phase coil (12u, 12v, 12w), and a magnetic pole sensor (Hall elements H1 to H3) for detecting the magnetic pole.

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

The U-phase bridge 21u is configured by connecting a U-phase upper switching element UH on the high potential side and a U-phase lower switching element UL on the low potential side in series. The V-phase bridge 21v is configured by connecting a V-phase upper switching element VH on the high potential side and a V-phase lower switching element VL on the low potential side in series. The W-phase bridge 21w is configured by connecting a W-phase upper switching element WH on the high potential side and a W-phase lower switching element WL on the low potential side 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.

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

The motor control unit 3 is composed of, for example, a microprocessor or the like. The motor control unit 3 outputs 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 the switching signal Su. When the switching signal Su is at High level, the U-phase upper switching element UH is turned on, and when the switching signal Su is at 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 the switching signal Sx. When the switching signal Sx is at High level, the U-phase lower switching element UL is turned on, and when the switching signal Sx is at Low level, the U-phase lower switching element UL is turned off.

The V-phase upper switching element VH can be switched on and off by the switching signal Sv. When the switching signal Sv is at High level, the V-phase upper switching element VH is turned on, and when the switching signal Sv is at Low level, the V-phase upper switching element VH is turned off.

The V-phase lower switching element VL can be switched on and off by the switching signal Sy. When the switching signal Sy is at High level, the V-phase lower switching element VL is turned on, and when the switching signal Sy is at 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 the switching signal Sw. When the switching signal Sw is at High level, the W phase upper switching element WH is turned on, and when the switching signal Sw is at 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 the switching signal Sz. When the switching signal Sz is at High level, the W phase lower switching element WL is turned on, and when the switching signal Sz is at 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 high. 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 U-phase terminal Tu has an open potential. 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 switching the pattern 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.

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

Similar to the U phase described above, the potential applied to the W phase terminal Tw is switched by switching the patterns of the switching signals Sw and Sz by the motor control unit 3, 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 converted into a Hall element detection signal having a binary level by the comparator.

The motor control unit 3 controls the switching signals Su to Sz according to the rotation position of the rotor 11 detected by the Hall element detection signal, and energizes the U-phase coil 12u, the V-phase coil 12v, and the W-phase coil 12w. To switch. As a result, a rotational force is applied to the rotor 11 to rotate the rotor 11 around the rotation axis J.

The motor 1 may be provided with a Hall IC instead of the Hall element. The Hall IC is an IC in which a 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 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 final gear of the speed reducer 4. The output shaft 5 is connected to a controlled body (not shown).

That is, the motor device 10 has a speed reducer 4 that slows down the rotation of the rotor 11 and outputs the speed reducer 4, and an output shaft 5 that transmits the output of the speed reducer 4 to the controlled body. Thereby, for example, if the controlled body is the arm portion of the robot, the torque of the rotor 11 can be transmitted to the arm portion 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, Sw based on the control signal CS input from the outside and the detection result by the position detector 6, and drives and controls the motor 1. Specifically, the duty of the switching signals Su, Sv, Sw is controlled as described later. This makes it possible to perform servo control to make mechanical parameters such as the position, speed, and acceleration of the output shaft 5 follow the target value. That is, the motor control unit 3 performs servo control by controlling the energization of the coil (12u, 12v, 12w) based on the detection result of the position detector 6.

The position detector 6 is, for example, any one of a resolver, an incremental encoder, an absolute encoder, a magnetic sensor, and a potentiometer. As a result, a position detector 6 suitable for servo control can be used.

FIG. 2 is a conceptual diagram showing an example in which the rotation position of the rotor 11 shown in FIG. 1 is represented by an electric angle. In FIG. 2, as shown in FIG. 1, a 4-pole rotor 11 is actually shown as a 2-pole. The counterclockwise rotation direction of the rotor 11 shown in FIG. 1 corresponds to the clockwise rotation direction of the rotor 11 in FIG. Using the arrow AR along the boundary between the north and south poles of the rotor 11 as a criterion, the Hall element H1 is set to 0 degrees in terms of electrical angle, and the Hall is displaced clockwise by 120 degrees from the 0 degree position. The Hall element H2 is located, and the Hall element H3 is located at a position further clockwisely displaced by 120 degrees from the position of the Hall element H2.

Each range divided by 60 degrees clockwise from the 0 degree position to 360 degrees is the unit electric angle position P1 to P6. The relationship between the electric angle θ _E and the mechanical angle θ _M is expressed by θ _E = (P / 2) × θ _M (P is the number of poles), so when the number of poles shown in FIG. 1 is four, , 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 electric angle positions P1 to P6 described above.

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

Thereby, the unit electric 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 electric angle positions P1 to P6 based on the Hall element detection signals SH1 to SH3, and generates switching signals Su to Sz according to the detected unit electric angle positions. FIG. 3 shows switching of switching signals Su to Sz. As a result, an appropriate rotational force can be applied to the rotor 11 according to the unit electric angle position, and the rotation of the rotor 11 can be continued.

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

Regarding the V-phase switching signals Sv and Sy, at the unit electric angle positions P3 to P4, the switching signal Sv is pulsed and Sy is the Low level, and at the unit electric angle positions P1 and P6, the switching signals Sv are the Low level and Sy. Is the High level, and at the unit electrical angle positions P2 and P5, both the switching signals Sv and Sy are set to the Low level.

Regarding the W-phase switching signals Sw and Sz, at the unit electric angle positions P5 to P6, the switching signal Sw is pulsed and Sz is the Low level, and at the unit electric angle positions P2 to P3, the switching signal Sw is the Low level and Sz. Is the High level, and at the unit electrical angle positions P1 and P4, both the switching signals Sw and Sz are set to the Low level.

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

As described above, since the switching signal is set to the high level in the electric angle section of 120 degrees in each phase, the drive method shown in FIG. 3 is referred to as a 120 degree energization method. When the switching signals Su, Sv, and Sw are pulsed, the duty control by the servo control described above is reflected.

<2. Regarding the 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, an appropriate driving signal is given to the motor 1, and the motor 1 can be driven and controlled. However, since the number of Hall elements required is large, it is disadvantageous in terms of cost.

Therefore, in the motor device 10X according to the second comparative example shown in FIG. 4, the Hall element provided in the motor 1X is one Hall element as a structural difference from the motor device 10 according to the first comparative example described above. It is set to H1.

The 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 the 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 electric angle position by dividing the period ΔT1 into three equal parts.

The motor control unit 3 has a pattern of switching signals Su to Sz (energization) at the unit electric angle position P5 estimated to be switched next at the timing tb in which the period Δt2 has elapsed from the timing ta at which the Hall element detection signal SH1 falls. Pattern) is generated and output to the inverter 2. Further, the motor control unit 3 generates a pattern of switching signals Su to Sz at the unit electric angle position P6 estimated to be switched next at the timing ct when the period Δt2 has elapsed from the timing tb and outputs the pattern to the inverter 2. do.

By doing so, it is possible to control the drive of the motor 1X while reducing the cost by using only one required Hall element. However, the estimated period Δt2 may deviate from the actual value depending on the condition of the load connected to the output shaft 5. For example, when the load suddenly increases and the actual value becomes considerably larger than the estimated period Δt2, the rotation of the rotor 11 is stopped by the load, the rotor 11 is reversed by the load, and so on. In such a case, when the motor 1X is driven by the energization pattern presumed to be switched next at the timing tb or tc, an appropriate rotational force can be applied to the rotor 11 from the coils 12u, 12v, 12W of each phase. It becomes impossible to continue the normal rotation of the rotor 11.

Similar 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. It is also performed to estimate the period corresponding to the unit electric angle position.

<3. Regarding an exemplary embodiment of the present invention>
An exemplary embodiment of the present invention will be described with reference to 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 required Hall element is used as one Hall element H1 to reduce the cost. What is different 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 the drive control of the motor 1X separately from the servo control.

The rotor 11 in the motor 1X is connected to the output shaft 6 via the speed reducer 4. As a result, 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.

The control method by the motor control unit 3 according to the present embodiment will be described with reference to the flowcharts shown in FIGS. 6 and 7. 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 rise timing to the fall timing of the Hall element detection signal SH1, the measured period ΔT1 is set to 3 or the like. By dividing, the period Δt corresponding to the unit electric angle position is estimated, and it is determined whether the estimated period Δt has elapsed. If the period Δt has not 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 forward rotation direction of the rotor 11 as compared with before the elapse of Δt. The normal rotation direction is the direction in which the unit electrical angle position is from P1 to P6. If it changes 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 referred to as the switch pattern) from the unit electric angle position P4 to P5. Switch to. On the other hand, if it does not change in the forward rotation direction (N in step S2), the process proceeds to step S9 (FIG. 7) described later.

In step S4 after step S3, the motor control unit 3 determines whether the period Δt has elapsed. If the period Δt has not 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 as compared with before the elapse of Δt. If it changes in the forward 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 electric angle position P5 to P6. On the other hand, if it does not change in the forward rotation direction (N in step S5), the process proceeds to step S9, which will be described later.

After step S6, the motor control unit 3 determines whether or not there is a change in the level of the Hall element detection signal SH1. That is, it is determined whether or not there is a change in the level of the Hall element detection signal SH1. 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 electric angle position P6 to 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 indicates that the change in the detection value PD of the position detector 6 is equal to or less than a 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 a predetermined value, but it is determined whether or not indicates reversal of the rotor 11. Reverse rotation is rotation in the direction opposite to the forward rotation direction.

If the change in the detected value PD is not more than a predetermined value, it is possible that the load prevents the rotor 11 from rotating in the forward rotation direction. 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 or not 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 forward rotation direction occurs (Y in step S11), the process proceeds to step S12. In step S12, it is determined whether the current switch pattern is for P6, and if not (N in step S12), the switch pattern is switched to the current switch pattern at the next unit electric angle position, and then step S4. Or proceed 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 detection 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 detection value PD does not change in step S9, but the rotor 11 does not change. It may be reversed due to the load. Since the rotation angle of the output shaft 5 is smaller than the rotation angle of the rotor 11 by the speed reducer 4, there is a possibility that the rotor 11 is reversed even if 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 whose unit electric angle position is one before the current switching pattern. Then, after switching to the switch pattern at the current next unit electric angle position, the process proceeds to steps S1, S4, or S7.

If the change in the detection value PD of the position detector 6 indicates the reversal of the rotor 11 in step S9, the process proceeds to step S13, and the motor control unit 3 has one unit electric angle position than the current switching pattern. Returns the switching pattern to the previous switching pattern. Then, after switching to the switch pattern at the current next unit electric angle position, the process proceeds to steps S1, S4, or S7.

For example, in the example shown in FIG. 5, the case where the detection value PD of the position detector 6 does not change at the timing ct when the period Δt has elapsed in step S4 is shown. 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, when the detected value PD changes 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 state (step S13). .. After that, the switch pattern is switched for P5, and the process proceeds to step S4.

When the motor control unit 3 measures the period ΔT2 from the falling timing to the rising timing of the Hall element detection signal SH1 in step S1, the measured period ΔT2 is divided into three equal parts to obtain the unit electric angle 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 electric angle position P1 to P2 in step S3, the switch pattern is switched from the unit electric angle position P2 to P3 in step S6, and the switch pattern is the unit electric angle in step S8. The position is switched from P3 to P4. Further, in step S14, it is determined whether the current switch pattern is for P3. Further, in step S7, it is determined whether or not there is a change in the level of the Hall element detection signal SH1.

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

As a result, even if the estimated value Δt for the period corresponding to the unit electric angle position deviates from the actual value due to the load applied to the motor 1X, the coil (12u, 12v, 12w) is energized with an appropriate energization pattern. It is possible to facilitate the continuation of normal rotation of the rotor 11. That is, it is possible to improve the control performance of the motor while reducing the number of magnetic pole sensors (Hall elements) to reduce the cost.

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

Further, when the motor control unit 3 determines that the change in the detection value PD of the position detector 6 is equal to or less than a predetermined value when the estimated period Δt elapses, the motor control unit 3 maintains the current energization pattern and the coil. (12u, 12v, 12w) is energized (step S10).

As a result, when the rotation of the rotor 11 is hindered by the load, the rotational force can be appropriately applied to the rotor 11 by the excitation of the coil.

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

As a result, even when the rotor 11 is reversed due to a large load, it is possible to appropriately apply a rotational force to the rotor 11 by exciting the coil.

Further, 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 by the reduction gear 4, the rotor 11 is used even when the change amount of the detection value of the position detector 6 is equal to or less than a predetermined value. May be in a reversed state, and an energization pattern suitable for the reverse rotation of the rotor 11 can be tried.

Further, when the motor control unit 3 detects the reversal 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 unit electric angle is higher than the current energization pattern. The coil (12u, 12v, 12w) is energized with the energization pattern one position before (step S13).

As a result, even when the rotor 11 is reversed due to a large load, it is possible to appropriately apply a rotational force to the rotor 11 by exciting the coil.

Further, in the present embodiment, the position detector 6 used for the servo control of the output shaft 5 can also be used for the control shown in FIGS. 6 and 7.

<4. Others>
Although the embodiments of the present invention have been described above, the embodiments can be changed in various ways 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 (pole pole sensor). It is possible to estimate the period Δt corresponding to the unit electric angle position which is the 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 including at least one of ΔT1 and ΔT2. That is, the motor control unit 3 estimates the period Δt corresponding to the unit electric angle position in the second half cycle based on the average value or the amount of change of the signal lengths in the plurality of first half cycles. Thereby, the period Δt corresponding to the unit electric angle position in the second half cycle can be estimated more accurately.

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

The present invention can be used, for example, in a motor device for a robot.

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 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 Phase lower switching element, 3 ... motor control unit, 4 ... reducer, 5 ... output shaft, 6 ... position detector, 10, 10X ... motor device

Claims (9)

A rotor with magnetic poles and
A stator with multi-phase coils and
A magnetic pole sensor that detects the magnetic pole and
With a motor and
A position detector that detects a change in the position of the rotor, and
A motor control unit that rotates the rotor by switching the energization pattern that energizes the coil with an AC voltage.
Have,
The motor control unit is a unit for switching 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 of the magnetic pole sensor. The coil is changed from the energization pattern estimated to be switched next based on the detection result of the position detector when the period corresponding to the corner position is estimated and the estimated period elapses. Energize the
Motor device. The motor device according to claim 1, wherein the first half cycle includes one half cycle immediately before the second half cycle. The motor control unit estimates the period corresponding to the unit electric angle position in the second half cycle based on the average value or the amount of change of the signal lengths in the plurality of first half cycles, claim 1 or claim. 2. The motor device according to 2. When 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 when the estimated period elapses, the motor control unit maintains the current energization pattern on the coil. The motor device according to any one of claims 1 to 3, wherein the motor device is energized. When the motor control unit maintains the current energization pattern and energizes the coil, and then determines that the change in the detection value of the position detector is equal to or less than the predetermined value, the current energization pattern The motor device according to claim 4, wherein the coil is energized with an energization pattern one before the unit electric angle position. It further has a speed reducer that slows down the rotation of the rotor and outputs it, and an output shaft that transmits the output of the speed reducer to the controlled body.
The motor device according to any one of claims 1 to 5, wherein the position detector detects the rotational position of the output shaft. The motor device according to claim 6, wherein the motor control unit performs servo control by controlling energization of the coil based on the detection result of the position detector. The motor device according to claim 7, wherein the position detector is any one of a resolver, an incremental encoder, an absolute encoder, a magnetic sensor, and a potentiometer. When the motor control unit detects the reversal of the rotor based on the change in the detection value of the position detector when the estimated period elapses, the unit electric angle position is higher than the current energization pattern. The motor device according to any one of claims 1 to 8, wherein the coil is energized with the previous energization pattern.

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