JP2018182972A - Driving control circuit for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving control circuit for a brushless motor that allows lead angles to be easily adjusted using a plurality of hall elements.SOLUTION: A driving control circuit 1 for a brushless motor comprises a magnetic pole detecting part 25, a control circuit part 4 for controlling driving of the motor, a switch changeover part 5, and a hall signal changeover output part 6. A plurality of hall elements of the magnetic pole detecting part 25 are arranged to have lead angles different from each other in a rotation direction of a rotor of the motor 20, which detect positions of magnetic poles of the rotor, respectively and output hall signals Sh1 and Sh2. The switch changeover part 5 outputs a changeover signal Ss for selecting any of the Hall signals Sh1 and Sh2 outputted from the magnetic pole detecting part 25. The hall signal changeover output part 6 is inputted with the hall signals Sh1 and Sh2 and the changeover signal Ss, and outputs selected complementary signals Sha and Shb selected based on the inputted changeover signal Ss, out of the hall signals Sh1 and Sh2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a drive control circuit of a brushless motor, and more particularly to a drive control circuit of a brushless motor for driving a brushless motor provided with a plurality of Hall elements.

  In general, in a brushless motor, the higher the rotation speed, the lower the efficiency due to the delay of the winding current with respect to the induced voltage. One way to improve this is to control the advance angle. However, when a general-purpose integrated circuit (IC) or an inexpensive microcomputer is used for a motor drive control circuit, it is often difficult to realize advance angle control. In addition, even in the case of a general-purpose IC configured to be able to perform advance angle control, the amount of advance may be insufficient in a high rotation speed range (for example, about 100,000 revolutions or the like).

  Patent Document 1 below provides a plurality of Hall ICs for detecting the poles of the rotor magnet, and changes the lead angle by switching one of the plurality of Hall ICs used for the rotation of the motor using a switch means. Discloses a configuration of a drive circuit of a brushless motor capable of

Japanese Patent Application Laid-Open No. 6-311780

  By the way, the circuit configuration as disclosed in the above-mentioned Patent Document 1 is a case where a Hall IC is used, and can not be coped with when a Hall element that outputs two output signals is used. In addition, when a logic circuit is used as switch means for switching a signal from the Hall element, the influence of distortion of the waveform becomes large when the amplitude of the detection signal from the Hall element is small. When a relay is used as the switch means, there is a problem that the size of the circuit becomes large.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide a drive control circuit of a brushless motor which can easily perform advance angle adjustment using a plurality of Hall elements. .

  In order to achieve the above object, according to one aspect of the present invention, a drive control circuit of a brushless motor is arranged to have lead angles different from each other in the rotational direction of a motor rotor, and detect positions of magnetic poles of the rotor respectively. A plurality of Hall elements outputting complementary signals, a switching signal output unit outputting a switching signal for selecting any of the plurality of complementary signals output from the plurality of Hall elements, a plurality of complementary signals and a switching signal And a Hall signal switching output unit that outputs a selection complementary signal selected based on the input switching signal among the plurality of complementary signals, and the selection complementary signal output from the Hall signal switching output unit. A control circuit unit that outputs a drive control signal for controlling the drive of the motor; a motor drive unit that outputs a drive signal to the motor based on the drive control signal; Provided.

  Preferably, the Hall signal switching output unit is configured to receive a plurality of complementary signals and a plurality of analog switches arranged to output any one pair of complementary signals, and a plurality of analog switches according to the switching signal. The switch has a switch for switching operation, and when the switch performs switching operation, the selection complementary signal output from the plurality of analog switches is switched.

  Preferably, the plurality of Hall elements include a first Hall element and a second Hall element, and the plurality of analog switches include a first analog switch and a second analog switch, and the first analog switch , One of the first complementary signals output from the first Hall element and one of the second complementary signals output from the second Hall element are input to the second analog switch. When the other of the signals and the other of the second complementary signals are input and the first analog switch outputs one of the first complementary signals as the selection complementary signal, the second analog switch selects the other of the first complementary signals When outputting as a complementary signal and the first analog switch outputs one of the second complementary signals as a selection complementary signal, the second analog switch outputs the other of the second complementary signals as a selection complementary signal That.

  Preferably, the control circuit unit detects the rotational speed of the motor, and the switching signal output unit outputs the switching signal based on the detection result of the rotational speed of the motor of the control circuit unit.

  Preferably, the control circuit unit detects the rotational speed of the motor, and the second Hall element is disposed at a position advanced in the rotational direction of the rotor relative to the first Hall element, and the switching signal output unit Compares the motor rotation speed, the first predetermined value, and the second predetermined value smaller than the first predetermined value based on the detection result of the motor rotation speed, and determines the first Hall element When the rotational speed of the motor exceeds the first predetermined value in the state where the drive control used is being performed, the switch is turned on by the switch signal, and the drive control using the second Hall element is performed. When the rotational speed of the motor falls below the second predetermined value in the above state, the changeover switch is turned off by the changeover signal.

  According to these inventions, it is possible to provide a drive control circuit of a brushless motor capable of easily performing advance angle adjustment using a plurality of Hall elements.

FIG. 1 is a block diagram showing a circuit configuration of a drive control circuit of a brushless motor according to an embodiment of the present invention. It is a figure which shows an example of the motor driven by a drive control circuit. It is a figure explaining the structure of the Hall signal switching output part of a drive control circuit. It is a figure which shows an example of an analog switch. It is a flowchart which shows an example of the flow of operation | movement of a drive control circuit.

  Hereinafter, a drive control circuit of a brushless motor according to an embodiment of the present invention will be described.

  Embodiment

  FIG. 1 is a block diagram showing a circuit configuration of a drive control circuit of a brushless motor according to an embodiment of the present invention.

  As shown in FIG. 1, a drive control circuit (hereinafter sometimes simply referred to as a drive control circuit) 1 of a brushless motor drives a motor 20. In the present embodiment, the motor 20 is, for example, a three-phase brushless motor. The drive control circuit 1 causes the motor 20 to rotate by periodically supplying a drive current to the armature coils Lu, Lv, Lw of the motor 20.

  The drive control circuit 1 includes a motor drive unit 2, a control circuit unit 4, a switch switching unit (an example of a switching signal output unit) 5, a hall signal switching output unit 6, and a first hall element 251 as described later. It has a magnetic pole detection unit (an example of a plurality of Hall elements) 25 having (shown in FIG. 2) and a second Hall element 252 (shown in FIG. 2). The components of drive control circuit 1 shown in FIG. 1 are a part of the whole, and drive control circuit 1 has other components in addition to those shown in FIG. May be As described later, the switch switching unit 5 outputs the Hall signals Sh1a and Sh1b (an example of a complementary signal) output from the first Hall element 251 and the Hall signals Sh2a and Sh2b (Complementary output from the second Hall element 252). A switching signal for selecting any one of the signal examples is output. Further, the hall signal switching output unit 6 receives the above-mentioned hall signal (a plurality of complementary signals) and a switching signal, and selects one of the above-mentioned hall signals (a plurality of complementary signals) based on the inputted switching signal. The selected complementary signals Sha and Shb are output. The control circuit unit 4 outputs a drive control signal Sd for controlling the drive of the motor 20 based on the selection complementary signals Sha and Shb output from the Hall signal switching output unit 6. Then, the motor drive unit 2 outputs a drive signal to the motor 20 based on the drive control signal Sd.

  In the present embodiment, the drive control circuit 1 is an integrated circuit device (IC) in which the whole is packaged except for the magnetic pole detection unit 25. Note that a part of the drive control circuit 1 may be packaged as one integrated circuit device, or all or a part of the drive control circuit 1 may be packaged together with other devices to form one integrated circuit device. May be configured.

  The motor drive unit 2 has an inverter circuit 2a and a predrive circuit 2b. As described later, a drive control signal Sd for controlling the drive of the motor 20 is input to the motor drive unit 2. The motor drive unit 2 outputs a drive signal to the motor 20 based on the drive control signal Sd output from the control circuit unit 4 to drive the motor 20.

  The predrive circuit 2b generates an output signal for driving the inverter circuit 2a based on the drive control signal Sd output from the control circuit unit 4, and outputs the output signal to the inverter circuit 2a. The inverter circuit 2a outputs a drive signal to the motor 20 based on the output signal output from the predrive circuit 2b to energize the armature coils Lu, Lv, Lw provided in the motor 20. In inverter circuit 2a, for example, a pair of series circuits of two switch elements provided at both ends of DC power supply Vcc corresponds to each phase (U phase, V phase, W phase) of armature coils Lu, Lv, Lw. Are arranged and configured. In each pair of two switch elements, terminals of each phase of the motor 20 are connected to connection points of the switch elements (not shown). The predrive circuit 2b outputs, for example, six types of signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl corresponding to the switch elements of the inverter circuit 2a as output signals. When these signals are output, the switch elements corresponding to the respective signals are turned on and off, a drive signal is output to the motor 20, and power is supplied to each phase of the motor 20 (not shown) .

  In the present embodiment, a speed command signal Sc is input to the control circuit unit 4. The control circuit unit 4 also receives selection complementary signals (two complementary signals selected by the hall signal switching output unit 6) Sha and Shb output from the hall signal switching output unit 6 as described later. . The control circuit unit 4 performs drive control of the motor 20 based on the speed command signal Sc and the selection complementary signals Sha and Shb.

  The speed command signal Sc is input from the outside of the control circuit unit 4, for example. The speed command signal Sc is a signal related to the rotational speed (rotational speed) of the motor 20. For example, the speed command signal Sc is a PWM (Pulse Width Modulation) signal or a clock signal corresponding to the target rotational speed of the motor 20.

  As described later, the selection complementary signals Sha and Shb input to the control circuit unit 4 are signals corresponding to the rotation of the rotor 21 (shown in FIG. 2) of the motor 20. The control circuit unit 4 detects the rotational state of the motor 20 using the selection complementary signals Sha and Shb, and controls the drive of the motor 20. That is, the control circuit unit 4 controls the drive of the motor 20 by obtaining the actual rotational speed information on the actual rotational speed of the rotor 21 of the motor 20 using the selection complementary signals Sha and Shb. Further, the control circuit unit 4 detects the rotational position of the rotor 21 of the motor 20 using the selection complementary signals Sha and Shb, and controls the drive of the motor 20.

  The control circuit unit 4 detects the rotational speed of the motor 20 and outputs the detection result to the switch switching unit 5. That is, the control circuit unit 4 outputs a rotation speed signal (an example of a detection result of the rotation speed) Sr corresponding to the rotation speed of the motor 20 to the switch switching unit 5.

  The switch switching unit 5 outputs the switching signal Ss based on the input rotational speed signal Sr, that is, based on the detection result of the rotational speed of the motor 20. The switch switching unit 5 compares, for example, two predetermined values (first predetermined value and second predetermined value) set in advance with the rotational speed of the motor 20 corresponding to the rotational speed signal Sr. The switch switching unit 5 outputs the switching signal Ss based on the comparison result. The switching signal Ss is output to the hall signal switching output unit 6.

  FIG. 2 is a view showing an example of the motor 20 driven by the drive control circuit 1.

  In FIG. 2, a cross-sectional structure in a plane perpendicular to the rotation axis of the motor 20 is schematically shown. The motor 20 is, for example, an outer rotor type motor. The motor 20 has a rotor 21 to which a magnet 22 is attached, and a stator 23 composed of a coil, a stator yoke and the like. The motor 20 may be an inner rotor type motor. Further, the number of poles of the motor 20, the number of slots, etc. are not limited to these.

  In the present embodiment, the magnetic pole detection unit 25 includes two Hall elements of a first Hall element 251 and a second Hall element 252 (hereinafter, the magnetic pole detection unit 25 may be referred to as two Hall elements 25). have. The two Hall elements 25 lead different from each other in the rotation direction of the rotor 21 of the motor 20 (in the clockwise direction around the rotation axis of the motor 20, but not limited to this, it may be in the counterclockwise direction) It is arranged to have a corner. In other words, the first Hall element 251 and the second Hall element 252 are disposed at mutually different positions in the rotational direction of the rotor 21. As shown in FIG. 2, the first Hall element 251 and the second Hall element 252 are disposed at an interval of a predetermined angle X degrees in the rotational direction of the rotor 21. In the case where the first Hall element 251 shown in FIG. 2 is at an advancing angle of 0 degree with respect to the position of the stator 23, the second Hall element 252 is disposed at a position advanced by X degrees. It can be said that For example, the X degree is, but not limited to, 30 degrees.

  The first Hall element 251 detects the position of the magnetic pole of the rotor 21 and outputs a first complementary signal (an example of a complementary signal; an example of a pair of complementary signals) Sh1. The first complementary signal Sh1 includes a positive side Hall signal (one example of the first complementary signal) Sh1a and a negative side Hall signal (the other example of the first complementary signal) Sh1b having a complementary relationship with each other. . The second Hall element 252 detects the position of the magnetic pole of the rotor 21 and outputs a second complementary signal (an example of a complementary signal; an example of a pair of complementary signals) Sh2. The second complementary signal Sh2 includes a positive side Hall signal (one example of the second complementary signal) Sh2a and a negative side Hall signal (the other example of the second complementary signal) Sh2b having a complementary relationship with each other. . That is, the two Hall elements 25 output two sets of complementary signals Sh1 (Sh1a, Sh1b) and Sh2 (Sh2a, Sh2b) according to the position of the magnetic pole of the rotor 21.

  FIG. 3 is a diagram for explaining the configuration of the Hall signal switching output unit 6 of the drive control circuit 1.

  As shown in FIG. 3, the Hall signal switching output unit 6 includes two analog switches 61 and 62 (a first analog switch 61 and a second analog switch 62; an example of a plurality of analog switches) and a switching switch 65. And. Hall signals Sh1a and Sh2a (an example of complementary signals) are input to the two analog switches 61, and Hall signals Sh1b and Sh2b (an example of complementary signals) are input to the analog switch 62, and a first complementary signal Sh1 It is arranged to output any one pair of complementary signals of a pair of complementary signals consisting of Hall signals Sh1a and Sh2b and a second complementary signal Sh2 (a pair of complementary signals consisting of Hall signals Sh1b and Sh2b) . The changeover switch 65 performs the switching operation of the two analog switches 61 and 62 in accordance with the changeover signal output from the switch changeover unit 5. When the changeover switch 65 performs the switching operation, the selection complementary signals Sha and Shb output from the two analog switches 61 and 62 are switched. Further, as described later, the Hall signal Sh1a (one example of the first complementary signal) output from the first Hall element 251 and the second Hall element 252 are output to the first analog switch 61. The Hall signal Sh2a (one example of the second complementary signal) is input, and the second analog switch 62 receives the Hall signal Sh1b (the other example of the first complementary signal) and the Hall signal Sh2b (the second complementary signal). When the first analog switch 61 outputs the hall signal Sh1a, the second analog switch 62 outputs the hall signal Sh1b as the selection complementary signals Sha and Shb, and the first analog switch is input. When 61 outputs the Hall signal Sh2a, the second analog switch 62 selects the Hall signal Sh2b as the selection complementary signals Sha and Shb. Forces.

  FIG. 4 is a diagram showing an example of the analog switches 61 and 62. As shown in FIG.

  As shown in FIG. 4, the analog switches 61 and 62 respectively have an IN terminal to which a signal for operating the analog switches 61 and 62 is input, and a V + terminal connected to a power supply voltage (for example, 5 volts). , A GND terminal connected to the ground potential, two NO terminals and NC terminals for input, and a COM terminal to which a signal of either the NO terminal or the NC terminal is output.

  In the analog switches 61 and 62, for example, the state in which the COM terminal and the NO terminal are connected depending on whether the signal input to the IN terminal is low (L) or high (H); Switches between the state in which the terminal and the NC terminal are connected. For example, when the signal input to the IN terminal is low, the COM terminal and the NC terminal are connected, and the COM terminal and the NO terminal are not connected. On the other hand, when the signal input to the IN terminal is high, the COM terminal and the NC terminal are not connected, and the COM terminal and the NO terminal are connected.

  Thus, as the analog switches 61 and 62, those having a general configuration can be used. As the analog switches 61 and 62, one having a resistance of several ohms can be used. Since the outputs of the complementary signals output from the two Hall elements 25 are minute (for example, about ± 100 mV), the characteristics of the analog switches 61 and 62 may be selected to have small on-resistance. Further, in consideration of use at high speed rotation, it is sufficient to select the analog switches 61 and 62 having a high ON-OFF switching speed.

  Returning to FIG. 3, the first analog switch 61 receives the Hall signal (one example of the first complementary signal) Sh 1 a output from the first Hall element 251 and the second Hall element 252. A Hall signal (an example of one of the second complementary signals) Sh2a is input. The hall signal Sh1a is input to the NC terminal of the first analog switch 61. The hall signal Sh2a is input to the NO terminal of the first analog switch 61.

  In the second analog switch 62, the Hall signal (one example of the other of the first complementary signal) Sh1b output from the first Hall element 251, and the Hall signal (second complement) output from the second Hall element 252 Another example of the signal) Sh2b is input. The hall signal Sh1b is input to the NC terminal of the second analog switch 62. The hall signal Sh2b is input to the NO terminal of the second analog switch 62.

  That is, in the present embodiment, one of the two output terminals of the first Hall element 251 is connected to the NC terminal of the first analog switch 61, and the other is connected to the NC terminal of the second analog switch 62. It is done. Also, one of the two output terminals of the second Hall element 252 is connected to the NO terminal of the first analog switch 61, and the other is connected to the NO terminal of the second analog switch 62. In other words, the first complementary signal Sh1 output from the first Hall element 251 is input to the NC terminal of each of the two analog switches 61 and 62, and the second complementary signal output from the second Hall element 252 Sh2 is input to the NO terminal of each of the two analog switches 61 and 62.

  The COM terminal of the first analog switch 61 and the COM terminal of the second analog switch 62 are connected to the control circuit unit 4. A selected complementary signal (a signal on the plus side of the complementary signal) Sha selected from the first complementary signal Sh1 and the second complementary signal Sh2 is output to the control circuit unit 4 from the COM terminal of the first analog switch 61. Ru. A selected complementary signal (a signal on the negative side of the complementary signal) Shb selected from the first complementary signal Sh1 and the second complementary signal Sh2 is output to the control circuit unit 4 from the COM terminal of the second analog switch 62. Ru.

  The changeover switch 65 switches whether to connect the voltage applied to one end to the respective IN terminals of the two analog switches 61 and 62 via a resistor based on the power supply voltage (5 V in this example). The other end of the changeover switch 65 is connected to the IN terminal of each of the two analog switches 61 and 62. When the changeover switch 65 performs such a switching operation, the selection complementary signals Sha and Shb output from the two analog switches 61 and 62 are switched as described below.

  When the changeover switch 65 is off, the signal input to the IN terminal of each of the two analog switches 61 and 62 becomes low (L). At this time, in each of the two analog switches 61 and 62, the COM terminal and the NC terminal are connected. Therefore, the first complementary signal Sh1 output from the first Hall element 251 is output from the two analog switches 61 and 62 as the selection complementary signals Sha and Shb, and is input to the control circuit unit 4. Thereby, the control circuit unit 4 outputs the drive control signal Sd according to the position of the magnetic pole of the rotor 21 detected by the first Hall element 251. That is, the control circuit unit 4 performs drive control using the first Hall element 251 (selecting the first complementary signal Sh1).

  On the other hand, when the changeover switch 65 is on, the signals input to the respective IN terminals of the two analog switches 61 and 62 become high (H). At this time, in each of the two analog switches 61 and 62, the COM terminal and the NO terminal are connected. Therefore, the second complementary signal Sh2 output from the second Hall element 252 is output from the two analog switches 61 and 62 as the selection complementary signals Sha and Shb, and is input to the control circuit unit 4. Thereby, the control circuit unit 4 outputs the drive control signal Sd according to the position of the magnetic pole of the rotor 21 detected by the second Hall element 252. That is, the control circuit unit 4 performs drive control using the second Hall element 252 (selecting the second complementary signal Sh2).

  In the case where the second Hall element 252 is arranged to be advanced by X degrees in the rotational direction of the rotor 21 relative to the first Hall element 251 as shown in FIG. 2, the second Hall element 252 is The used drive control is performed at a timing advanced by an X degree even when the control content by the control circuit unit 4 is not changed as compared with the case where the drive control using the first Hall element 251 is performed. The control signal Sd is output.

  The changeover switch 65 performs an on / off operation according to the switching signal Ss output from the switch switching unit 5. That is, the switch switching unit 5 switches whether the switching switch 65 is turned on or off by outputting the switching signal Ss. In other words, the switch switching unit 5 switches whether to select one of the first and second complementary signals Sh1 and Sh2 output from the two Hall elements 25 by outputting the switching signal Ss.

  In the present embodiment, switch switching unit 5 compares the rotational speed of motor 20 with a first predetermined value and a second predetermined value based on rotational speed signal Sr. The first and second predetermined values are each a threshold of the rotational speed set in advance, and the first predetermined value is a value larger than the second predetermined value. In the state where the switch 65 is turned off, that is, in the state where drive control using the first Hall element 251 is being performed, the switching speed of the motor 20 does not fall below the first predetermined value. In the case (when the first predetermined value is exceeded), the changeover switch 65 is turned on by the changeover signal Ss. On the other hand, when the switching speed of the motor 20 is equal to or higher than the second predetermined value in the state where the switching switch 65 is turned on, that is, the driving control using the second Hall element 252 is performed. If the switch 65 disappears (if it falls below the second predetermined value), the switch 65 is turned off by the switch signal Ss.

  Since the difference is provided between the first predetermined value and the second predetermined value as described above, the switching operation of the changeover switch 65 is provided with hysteresis characteristics. Therefore, the drive control using the first Hall element 251 and the drive control using the second Hall element 252 do not frequently switch, and the motor 20 can be smoothly driven in a wide rotational speed region.

  The first predetermined value and the second predetermined value can be determined by comparing the power consumption of the motor 20 at respective rotational speeds of the two Hall elements 25. That is, in the speed region lower than the predetermined rotation speed, the power consumption of the motor 20 is smaller when the drive control using the first Hall element 251 is performed, and in the speed region higher than the predetermined rotation speed. In the case where the power consumption of the motor 20 is reduced by the drive control using the Hall element 251 of No. 2, the first predetermined value and the second predetermined value with a predetermined speed difference based on the predetermined rotation speed. A predetermined value can be set. For example, assuming that the predetermined rotation speed is 100,000 revolutions per minute, the first predetermined value is set to 105,000 revolutions per minute, and the second predetermined value is set to 950,000 revolutions per minute, etc. can do. Note that the first predetermined value and the second predetermined value may be appropriately set according to the characteristics of the motor 20, the application, and the like.

  FIG. 5 is a flow chart showing an example of the flow of the operation of the drive control circuit 1.

  As shown in FIG. 5, in step S11, the control circuit unit 4 detects whether or not the speed command signal Sc is input to rotate the motor 20 (whether the speed command is turned on). If the speed command signal Sc is input, the process proceeds to step S12.

  In step S12, the control circuit unit 4 outputs the drive control signal Sd to start the rotation of the motor 20.

  In step S13, the switch switching unit 5 turns off the switching switch 65 by the switching signal Ss. As a result, the signal input to the IN terminal of the two analog switches 61 and 62 becomes low (L), and drive control using the first Hall element 251 is performed.

  In step S14, the switch switching unit 5 detects whether the rotation speed of the motor 20 is equal to or less than a first predetermined value based on the rotation speed signal Sr. If the rotational speed is equal to or less than the first predetermined value, the process proceeds to step S18. On the other hand, if the rotational speed is not less than the first predetermined value (that is, if the rotational speed exceeds the first predetermined value), the process proceeds to step S15.

  In step S15, the switch switching unit 5 turns on the switch 65 by the switching signal Ss. As a result, the signal input to the IN terminal of the analog switches 61 and 62 becomes high (H), and drive control using the second Hall element 252 is performed. When the rotational speed of the motor 20 exceeds a first predetermined value and becomes relatively high, the energization timing of the motor 20 can be advanced, and the motor 20 can be efficiently driven.

  In step S16, the switch switching unit 5 detects whether the rotational speed of the motor 20 is equal to or higher than a second predetermined value, based on the rotational speed signal Sr. If the rotational speed is equal to or higher than the second predetermined value, the process proceeds to step S18. On the other hand, if the rotational speed is not at least the second predetermined value (that is, if the rotational speed is less than the second predetermined value), the process proceeds to step S17.

  In step S17, the switch switching unit 5 turns off the changeover switch 65 by the switching signal Ss. As a result, the signal input to the IN terminal of the analog switches 61 and 62 becomes low (L), and drive control using the first Hall element 251 is performed.

  In step S18, the control circuit unit 4 detects whether or not the speed command signal Sc for stopping the motor 20 is input (whether the speed command is turned off). If the speed command signal Sc for stopping the motor 20 is input, the process proceeds to step S19. If the speed command signal Sc for stopping the motor 20 is not input, the processes after step S14 are performed again.

  In step S19, the control circuit unit 4 performs control to stop the motor 20. If control to stop the motor 20 is performed, it will return to the process of step S11.

  As described above, in the present embodiment, the first complementary signals Sh1 (Sh1a and Sh1b) and the second complementary signals Sh2 (the second complementary signals Sh1a and Sh1b) output from the two Hall elements 25 arranged to have different lead angles. A switch signal Ss for selecting any one of Sh2a and Sh2b) is output from the switch switching unit 5. Then, the Hall signal switching output unit 6 to which the switching signal Ss and the first complementary signal Sh1 and the second complementary signal Sh2 are input selects the selected complementary signals Sha and Shb selected based on the switching signal Ss. Output to Therefore, as compared with the case where one of two Hall elements 25 (first Hall element 251 and second Hall element 252) is used to drive motor 20, high efficiency is achieved in a wide range of rotational speed. Can drive the motor 20. Since an inexpensive Hall element can be used as the magnetic pole detection element, the manufacturing cost of the drive control circuit 1 can be reduced.

  As the control circuit unit 4, one that does not have a function of performing advance angle control can be used. In this case, as described above, it is possible to perform drive control with different lead angles by switching which of the two Hall elements 25 is used according to the rotational speed. Further, as the control circuit unit 4, one having an advance angle control function of performing advance angle control in a predetermined range can be used. In this case, by switching which of the two Hall elements 25 is used, the lead angle can be adjusted in a range wider than the range where the control circuit unit 4 can perform the lead angle control function. become.

  Which one of the two Hall elements 25 is used as the selection complementary signals Sha and Shb is switched by the two analog switches 61 and 62 having low resistance values. Therefore, the selection complementary signals Sha and Shb used for drive control are switched without losing the slight change of the first complementary signals Sh1 (Sh1a and Sh1b) and the second complementary signals Sh2 (Sh2a and Sh2b) output from the Hall element 25. be able to.

  Also, by using two analog switches 61 and 62, the Hall signal output from the first Hall element 251 and the Hall signal output from the second Hall element 252 can be used with a relatively simple circuit configuration. The complementary signals (first complementary signal Sh1 and second complementary signal Sh2) of the system can be switched while being synchronized (simultaneously).

  By appropriately setting the positions of the two Hall elements 25 and setting the first predetermined value and the second predetermined value, etc., and appropriately setting the switching timing of the switch switching unit 5, even in the forward rotation It is possible to realize the drive control circuit 1 capable of driving the motor 20 with high efficiency even during reverse rotation.

  [Others]

  The drive control circuit is not limited to the circuit configuration as shown in the above-described embodiment or the modification thereof. Various circuit configurations can be applied that are configured to meet the objectives of the present invention.

  The number of hall elements may be two or more. Even if the number is three or more, analog switches and changeover switches are configured in multiple stages, and the operation of each changeover switch is controlled by the switch changeover unit to be used for drive control among complementary signals output from each Hall element It suffices to be able to select complementary signals.

  The position of the Hall element is not limited to the position as described above. For example, in order to realize a small angle deviation such that the Hall elements hit each other, they are disposed on the diagonally opposite side according to the number of poles etc., and the polarity of the detection signal is reversed as necessary. It is also good.

  The configuration of the hall signal switching output unit is not limited to the above-described configuration. For example, the circuit that switches the hall signal is not limited to the analog switch. Further, each analog switch may be provided with a changeover switch, or the changeover switch may not be used. For example, a signal for controlling the operation of the analog switch may be directly output from the control circuit unit 4 or the like, and may be input to the IN terminal (the control circuit unit 4 or the like may function as a switching signal output unit. ). Also, the internal configuration of the analog switch is not limited to that described above. For example, an analog switch including two circuits capable of switching two Hall elements may be used.

  The number of phases of the brushless motor driven by the motor drive control circuit of the present embodiment is not limited to three phases, and may be another number of phases such as a single phase.

  The above-described flowchart and the like show an example for explaining the operation, and the present invention is not limited to this. The steps shown in the flowcharts are specific examples and are not limited to this flow. For example, the order of each step may be changed or another process may be inserted between the steps. And the processing may be parallelized.

  Some or all of the processing in the above-described embodiment may be performed by software or may be performed using a hardware circuit. For example, the control circuit unit is not limited to a microcomputer. The internal configuration of the control circuit unit may be at least partially processed by software.

  It should be understood that the above embodiments are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by claims, and is intended to include all modifications within the meaning and scope equivalent to claims.

1 Drive control circuit (Brush motor drive control circuit)
2 motor drive unit 4 control circuit unit 5 switch switching unit (an example of a switching signal output unit)
6 Hall signal switching output unit 20 motor 21 rotor 22 magnet 23 stator 25 magnetic pole detection unit (two Hall elements; an example of a plurality of Hall elements)
61 First analog switch (an example of multiple analog switches)
62 Second analog switch (an example of multiple analog switches)
65 changeover switch 251 first Hall element 252 second Hall element Sh1 first complementary signal (an example of a complementary signal; an example of a pair of complementary signals)
Sh1a Hall signal (example of complementary signal; one example of first complementary signal)
Sh1b Hall signal (an example of a complementary signal; another example of a first complementary signal)
Sh2 Second complementary signal (an example of complementary signals; an example of a pair of complementary signals)
Sh2a Hall signal (example of complementary signal; one example of second complementary signal)
Sh2b Hall signal (example of complementary signal; another example of second complementary signal)
Sha, Shb Selection complementary signal Sc Speed command signal Sr Rotational speed signal (Example of detection result of rotational speed)
Ss switching signal Sd drive control signal

Claims (5)

A plurality of Hall elements which are arranged to have different lead angles in the rotational direction of the motor rotor, and which detect the positions of the magnetic poles of the rotor and output complementary signals,
A switching signal output unit that outputs a switching signal for selecting one of a plurality of complementary signals output from the plurality of Hall elements;
A Hall signal switching output unit that receives the plurality of complementary signals and the switching signal and outputs a selected complementary signal selected based on the switching signal that is input among the plurality of complementary signals;
A control circuit unit that outputs a drive control signal for controlling the drive of the motor based on the selection complementary signal output from the hall signal switching output unit;
And a motor drive unit for outputting a drive signal to the motor based on the drive control signal. The hall signal switching output unit is
A plurality of analog switches arranged to receive the plurality of complementary signals and output any one pair of complementary signals;
And a changeover switch for switching the plurality of analog switches in accordance with the switching signal,
The drive control circuit of the brushless motor according to claim 1, wherein the selection complementary signal output from the plurality of analog switches is switched by the switching switch performing the switching operation. The plurality of Hall elements include a first Hall element and a second Hall element,
The plurality of analog switches include a first analog switch and a second analog switch,
One of a first complementary signal output from the first Hall element and one of a second complementary signal output from the second Hall element are input to the first analog switch.
The other of the first complementary signal and the other of the second complementary signal are input to the second analog switch,
When the first analog switch outputs one of the first complementary signals as the selected complementary signal, the second analog switch outputs the other of the first complementary signals as the selected complementary signal;
The second analog switch outputs the other of the second complementary signals as the selection complementary signal when the first analog switch outputs one of the second complementary signals as the selection complementary signal. The drive control circuit of the brushless motor according to claim 1. The control circuit unit detects a rotational speed of the motor,
The drive control circuit for a brushless motor according to any one of claims 1 to 3, wherein the switching signal output unit outputs the switching signal based on a detection result of a rotational speed of the motor of the control circuit unit. . The control circuit unit detects a rotational speed of the motor,
The second Hall element is disposed at a position advanced in the rotational direction of the rotor relative to the first Hall element,
The switching signal output unit is
Comparing the rotation speed of the motor, a first predetermined value, and a second predetermined value smaller than the first predetermined value, based on the detection result of the rotation speed of the motor;
When the rotation speed of the motor exceeds the first predetermined value while drive control using the first Hall element is being performed, the switch is turned on by the switch signal,
When the rotational speed of the motor falls below the second predetermined value while drive control using the second hall element is being performed, the changeover switch is turned off by the changeover signal. The drive control circuit of the brushless motor according to 3.

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