JP2020061815A - Motor drive control device, motor, and blower - Google Patents

Abstract

To provide a motor drive control device capable of reducing power consumption at the time of startup operation, a motor employing the same, and a blower.SOLUTION: A motor drive control device comprises: a drive control unit which generates a rotating magnetic field by switching a pattern of electrification to a phase winding of a motor unit to which an AC voltage is applied, in a predetermined order and controls drive of the motor unit; a voltage detection unit which detects voltage of the phase winding; and a positional information generation unit which generates rotation direction positional information in a rotation direction of a rotor of the motor unit on the basis of a detection result of the voltage detection unit. In startup operation of the motor unit, the drive control unit implements forced commutation in which the rotor is forcedly rotationally driven by generating the rotating magnetic field and, in a case where the rotation direction positional information is not synchronized with rotation of the rotating magnetic field, repeats the implementation of the forced commutation by generating the rotating magnetic field of a different start phase.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a motor drive control device, a motor, and a blower device.

  A conventional motor is disclosed in Patent Document 1. This motor is a sensorless control system and includes a CPU, a current control circuit, a rotor position detector, a rotor, and a motor coil. The current control circuit applies a current to the motor coil based on a current control signal output from the CPU to generate a rotating magnetic field. As a result, the rotor is driven to rotate. The rotor position detector detects the rotational position of the rotor based on the induced voltage generated in the motor coil.

  When the motor is started, the motor coil is excited to forcibly move the rotor. At this time, when the rotor position detection unit does not detect the rotation of the rotor, the starting current is increased to re-energize the motor coil and the starting process of the rotor is repeated.

JP-A-4-304190

  However, according to the motor disclosed in the above patent document, there is a problem that the power consumption during the startup operation increases due to the increase in the startup current.

  An object of the present disclosure is to provide a motor drive control device that can reduce power consumption during startup operation, a motor using the same, and a blower device.

  An exemplary motor drive control device of the present disclosure is configured to generate a rotating magnetic field by switching an energization pattern to a phase winding of a motor unit to which an AC voltage is applied in a predetermined order to control the drive of the motor unit. A control unit, a voltage detection unit that detects the voltage of the phase winding, and a position information generation unit that generates rotation direction position information in the rotation direction of the rotor of the motor unit based on the detection result of the voltage detection unit. The drive control unit performs forced commutation to generate the rotating magnetic field and forcibly rotate and drive the rotor in the start-up operation of the motor unit, and the rotation direction position information indicates the rotation. When not synchronized with the rotation of the magnetic field, the rotating magnetic fields having different start phases are generated and the forced commutation is repeated.

  According to the exemplary embodiments of the present invention, it is possible to provide a motor drive control device, a motor, and a blower device that can reduce power consumption during startup operation.

FIG. 1 is a block diagram showing an example of a blower. FIG. 2 is a flow chart for explaining an example of drive control of the motor section. FIG. 3 is a graph showing an example of the terminal voltage detected according to the electrical angle of the rotor in the sensorless control of the motor unit. FIG. 4 is a flowchart for explaining an example of starting operation of the motor unit.

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

  In the specification, in the blower 100, a direction parallel to the central axis CA of rotation of the motor unit 1 and the blade 111 is referred to as “axial direction”.

  Each of the U-phase winding 12u, the V-phase winding 12v, the W-phase winding 12w of the stator 11 of the motor unit 1 or a generic name of them may be referred to as a phase winding 12. In the three-phase AC voltage, a phase in which the phase winding 12 is energized is called an energized phase, and a phase in which the phase winding 12 is not energized is called a non-energized phase. A combination of two energized phase windings 12 is called an energization pattern. Further, each of the U-phase voltage, the V-phase voltage, the W-phase voltage of the three-phase AC voltage, or a generic term for them may be referred to as a phase voltage.

(1. Structure of blower)
FIG. 1 is a block diagram showing an example of the blower 100. In the present embodiment, the blower device 100 is an axial fan that generates an airflow that flows from one axial direction to the other. However, the present invention is not limited to this example, and the blower device 100 may be a centrifugal fan that blows out air that has been sucked in from the axial direction to the outside in the radial direction.

  As shown in FIG. 1, the blower device 100 includes an impeller 110 and a motor 120. The impeller 110 has blades 111 that are rotatable around a central axis CA that extends in the up-down direction. The motor 120 rotates the blades 111 by driving and rotating the impeller 110. Further, a DC power supply 200 is connected to the blower device 100. The DC power supply 200 is a power source of the blower 100. As shown in FIG. 1, the positive output terminal on the high voltage side of the DC power supply 200 is connected to the inverter 3 of the motor 120, which will be described later. The negative output terminal on the low voltage side of the DC power supply 200 is grounded.

(2. Motor components)
Next, each component of the motor 120 will be described. The motor 120 includes a motor unit 1, an inverter 3, and a motor drive control device 4.

  The motor unit 1 is a three-phase brushless DC motor (BLDC motor), and a three-phase AC voltage is applied from the inverter 3. The motor unit 1 includes a rotor 10 and a stator 11. The rotor 10 is provided with a permanent magnet. The stator 11 is provided with a U-phase winding 12u, a V-phase winding 12v, and a W-phase winding 12w. In the present embodiment, the phase windings 12u, 12v, 12w are Y-connected around a point 12c. In each of the phase windings 12u, 12v, 12w, ends on the side opposite to the point 12c are connected to terminals 13u, 13v, 13w of the motor unit 1, respectively. The phase windings 12u, 12v, 12w are not limited to this example, and may be Δ (delta) connected.

  The inverter 3 outputs a three-phase AC voltage to the motor unit 1. The inverter 3 has upper arm switches 31u, 31v, 31w and lower arm switches 32u, 32v, 32w. The upper arm switches 31u, 31v, 31w and the lower arm switches 32u, 32v, 32w form a bridge circuit that generates a three-phase AC voltage to be output to the motor unit 1. The bridge circuit includes a U-phase arm in which a high voltage side upper arm switch 31u and a low voltage side lower arm switch 32u are connected in series, a high voltage side upper arm switch 31v, and a low voltage side lower arm switch. It has an arm for V phase in which 32v is connected in series, and an arm for W phase in which an upper arm switch 31w on the high voltage side and a lower arm switch 32w on the low voltage side are connected in series. These arms are connected in parallel with each other. The high voltage side end of each arm is connected to the high voltage side terminal of the DC power supply 200. Therefore, a DC voltage from the DC power supply 200 is applied to each arm. The low voltage side end of each arm is grounded via a resistor 3a for current detection.

  The upper arm switches 31u, 31v, 31w and the lower arm switches 32u, 32v, 32w each include a switching element and a diode. For the switching element, for example, FET (field effect transistor), IGBT (insulated gate bipolar transistor), or the like is used. The diode is connected in parallel with the switching element with the direction from the low voltage side of the DC power supply 200 to the high voltage side as the forward direction. In other words, the anode of the diode is connected to the low voltage side end of the switching element, and the cathode is connected to the high voltage side end of the switching element. The diode functions as a freewheeling diode. Further, the diode may be a body diode built in the FET, or may be externally attached to the switching element.

  The motor drive control device 4 controls the drive of the motor unit 1. More specifically, the motor drive control device 4 performs PWM (Pulse Width Modulation) control on the inverter 3 and controls the drive of the motor unit 1 via the inverter 3. Further, the motor drive control device 4 detects the current flowing from the low voltage side end of the bridge circuit of the inverter 3 to the current detecting resistor 3a, and based on the detection result, the current value I flowing from the inverter 3 to the motor unit 1 is detected. To control.

(3. Components of the motor drive controller)
As shown in FIG. 1, the motor drive control device 4 includes a drive control unit 41, a current detection unit 42, a storage unit 43, a voltage detection unit 44, a determination unit 45, a position information generation unit 46, and a rotation. And a number detector 47.

  The drive control unit 41 controls the drive of the motor unit 1 to which the three-phase AC voltage is applied, and switches the energization pattern to the phase winding 12 of the motor unit 1 in a predetermined order n. Note that n is a positive integer. For example, the drive control unit 41 uses a program and information stored in the storage unit 43 to sensorlessly control the drive of the motor unit 1. Specifically, the drive control unit 41 controls the upper arm switches 31u, 31v, 31w or the lower arm switches 32u, 32v, 32w of the inverter 3 by PWM pulses, respectively. Accordingly, the drive control unit 41 can control the drive of the motor unit 1 by using the inverter 3 that outputs the three-phase AC voltage.

  The current detection unit 42 detects the current flowing through the current detection resistor 3 a connected between the bridge circuit of the inverter 3 and the ground terminal GND, and detects the current value as the current value I flowing through the motor unit 1. .

  The storage unit 43 is a non-volatile storage medium that maintains storage even when power supply is stopped. The storage unit 43 stores information used by each component of the motor drive control device 4, and particularly stores programs and control information used by the drive control unit 41. For example, the storage unit 43 stores the start phase of the rotating magnetic field generated in the execution of forced commutation described below and the number of times of forced commutation.

  The voltage detector 44 detects the terminal voltage of the terminal 13 connected to the non-energized phase winding 12 among the terminal voltages Vu, Vv, and Vw as an induced voltage generated in the phase winding 12. Specifically, the voltage detection unit 44 detects the terminal voltage Vu of the terminal 13u as the U-phase voltage of the U-phase winding 12u when the terminals 13v and 13w of the motor unit 1 are energized. Further, the voltage detection unit 44 detects the terminal voltage Vv of the terminal 13v as the V-phase voltage of the V-phase winding 12v when the terminals 13w and 13u of the motor unit 1 are energized. Further, the voltage detection unit 44 detects the terminal voltage Vw of the terminal 13w as the W-phase voltage of the W-phase winding 12w when the terminals 13u and 13v of the motor unit 1 are energized.

  The determination unit 45 makes various determinations. The position information generation unit 46 generates rotation direction position information in the rotation direction of the rotor 10 of the motor unit 1 based on the detection result of the voltage detection unit 44.

  The rotation speed detection unit 47 detects the rotation speed of the rotor 10 of the motor unit 1 based on the rotation direction position information.

(4. Motor drive control example)
Next, an example of drive control processing of the motor unit 1 by the motor drive control device 4 will be described. FIG. 2 is a flowchart for explaining an example of drive control of the motor unit 1. FIG. 3 is a graph showing an example of the terminal voltages Vu, Vv, Vw detected according to the rotational direction position of the rotor 10 in the sensorless control of the motor unit 1. Note that, in FIG. 3, the curved portions of the terminal voltages Vu, Vv, and Vw represent the terminal voltages when not energized.

  At the start of FIG. 2, the rotor 10 of the motor unit 1 is stopped or is rotating at a low speed. Therefore, in order to generate the induced voltage required to create the rotational direction position information in each phase winding 12u, 12v, 12w, the drive control unit 41 carries out the start-up operation of the motor unit 1 (step S1). In the state before the start-up operation, the rotor 10 stops or rotates at a low speed, so the position information generation unit 46 cannot generate the rotation direction position information of the rotor 10. Therefore, in the startup operation, the rotor 10 of the motor unit 1 is forcibly rotated by forced commutation.

  In forced commutation, the energization pattern is switched every predetermined energization period, and two of the three phase windings 12 of the motor unit 1 are energized and excited. The combination of the two phase windings 12 is switched in a predetermined order. As a result, a rotating magnetic field having a constant rotation speed is generated. In each energization pattern, the remaining one phase winding 12 is not energized. For example, if the energized phase is the U phase and the V phase, the non-energized phase is the W phase.

  Next, the drive control unit 41 carries out the synchronous operation of the motor unit 1 in order to accelerate the rotation of the rotor 10 (step S2). In the synchronous operation, the position information generation unit 46, in each energization pattern, the timing at which the phase voltage of the non-energized phase becomes the same as the virtual neutral point voltage Vn, and the increase / decrease of the phase voltage of the non-energized phase at the timing, for example. Rotation direction position information is created based on the tendency and the detection result of.

  For example, in the case of excitation as shown in FIG. 3, if the virtual neutral point voltage Vn is, for example, 3V, when the U phase is the non-conduction phase, the terminal voltage Vu increases to 3V, and the rotor 10 The rotational position of is detected as an electrical angle of 0 deg (or 360 deg). Further, at the point where the terminal voltage Vu decreases to 3 V, the rotational direction position of the rotor 10 is detected as an electrical angle of 180 deg.

  When the V-phase is the non-conduction phase, the rotational direction position of the rotor 10 is detected as 120 deg in electrical angle at the point where the terminal voltage Vv increases to 3V. Further, at the point where the terminal voltage Vv decreases to 3 V, the rotational direction position of the rotor 10 is detected as 300 deg in electrical angle.

  When the W phase is the non-energized phase, the rotational direction position of the rotor 10 is detected as an electrical angle of 60 deg at the point where the terminal voltage Vw decreases to 3V. Further, at the point where the terminal voltage Vw increases to 3 V, the rotational direction position of the rotor 10 is detected as an electrical angle of 240 deg.

  In the synchronous operation, the drive control unit 41 switches the energization pattern in accordance with the rotational direction position information for each energization period corresponding to the rotation speed of the rotor 10 detected by the rotation speed detection unit 47, whereby the rotor 10 is rotated. Accelerate the rotation.

  When the number of rotations becomes equal to or higher than the predetermined number, the drive control unit 41 carries out the steady control operation of the motor unit 1 (step S3). In the steady control operation, the rotor 10 is rotated at a desired rotation speed, and the energization pattern is switched according to the drive information of the motor unit 1 and the rotational direction position information. As a result, the motor unit 1 is driven. Then, when the drive of the motor unit 1 is stopped (YES in step S4), the drive control process of FIG. 2 ends.

(5. Example of starting operation of the motor section)
Next, an example of the startup operation of the motor unit 1 will be specifically described. FIG. 4 is a flowchart for explaining an example of the startup operation of the motor unit 1. When the start-up operation is started, in step S100, the drive control unit 41 performs an initial process, and the process proceeds to step S101. In the initial processing, the terminals 13u, 13v, and 13w of the motor unit 1 are short-circuited to perform a short brake. This causes the rotor 10 to stop. In addition, the number m of times of forced commutation stored in the storage unit 43 in the previous startup operation is reset and stores m = 0.

  In step S101, the drive control unit 41 performs forced commutation to generate a rotating magnetic field and forcibly rotate and drive the rotor 10. The rotating magnetic field of forced commutation switches the energization pattern a plurality of times during a constant energization period, whereby the electrical angle rotates by 60 deg at a constant rotation speed. The exciting phase of the rotating magnetic field is switched to the first exciting phase, the second exciting phase, and the third exciting phase in sequence every time the electrical angle shifts by 120 degrees. The rotating magnetic field of forced commutation makes two rotations by switching the energization pattern 12 times. Thereby, the starting success rate of the rotor 10 can be improved while shortening the implementation period of the forced commutation. When each energization period of the energization pattern is 12.8 ms, one forced commutation implementation period is 12.8 × 12 = 153.6 ms.

  When the starting electrical angle is 0 deg, the starting phase of the rotating magnetic field is the first excitation phase. Due to the rotation of the rotating magnetic field, the electrical angle changes in the order of 0 deg, 60 deg, 120 deg, 180 deg, 240 deg, 300 deg, 360 deg, 60 deg, 120 deg, 180 deg, 240 deg, 300 deg. Note that 360 deg is the same electrical angle as 0 deg.

  Immediately after the start of the forced commutation, the position information generation unit 46 generates rotation direction position information in the rotation direction of the rotor 10. When the forced commutation is completed, the number m of times of forced commutation is added once to store m = 1 in the storage unit 43, and the process proceeds to step S102.

  In step S102, the determination unit 45 determines whether or not the rotational direction position information is synchronized with the rotation of the rotating magnetic field. When the rotational direction position information is in synchronization with the rotation of the rotating magnetic field (YES in step S102), the motor unit 1 determines that the motor unit 1 is normally started, and proceeds to step S103. The determination in step S102 can be made based on whether or not the rotor 10 is rotating at a predetermined rotation speed with respect to the rotating magnetic field rotating at a constant rotation speed.

  In step S103, the starting phase of the rotating magnetic field of the forced commutation performed immediately before is stored in the storage unit 43. That is, the start phase of forced commutation is stored in the storage unit 43 when the rotational direction position information is synchronized with the rotation of the rotating magnetic field. After the start phase is stored in the storage unit 43, the startup operation ends. After the start-up operation is completed, the synchronous operation in step S2 of FIG. 2 is started.

  On the other hand, when the rotation direction position information is not synchronized with the rotation of the rotating magnetic field (NO in step S102), the motor unit 1 determines that the motor unit 1 has not been normally started, and proceeds to step S104.

  In step S104, it is determined whether the number m of times of forced commutation stored in the storage unit 43 has reached three times. In the start-up operation, the upper limit of the number of times of forced commutation is set to 3 times in advance. When the number of times of forced commutation has not reached three times (NO in step S104), the process proceeds to step S105.

  In step S105, the starting phase of the rotating magnetic field for the next forced commutation is changed, and the process returns to step S101. Specifically, the starting electrical angle of the rotating magnetic field is changed to 120 deg, and the second excitation phase becomes the starting phase.

  Accordingly, in the second forced commutation of step S101, the electrical angle is 120 deg, 180 deg, 240 deg, 300 deg, 360 deg, 60 deg, 120 deg, 180 deg, 240 deg, 300 deg, 360 deg, and 60 deg in that order due to the rotation of the rotating magnetic field. Change. Note that 360 deg is the same electrical angle as 0 deg.

  When the execution of the second forced commutation is completed, the number m of times of forced commutation is added once to store m = 2 in the storage unit 43, and in step S102, the motor unit 1 is normally started. If it is determined that the forced commutation has not been performed, the process proceeds from step S104 to step 105 similarly to after the first forced commutation.

  In step S105, the starting phase of the rotating magnetic field for the next forced commutation is changed, and the process returns to step S101. Specifically, the starting electrical angle of the rotating magnetic field is changed to 240 deg, and the third excitation phase becomes the starting phase.

  Thereby, in the third forced commutation of step S101, the electrical angle is 240 deg, 300 deg, 360 deg, 60 deg, 120 deg, 180 deg, 240 deg, 300 deg, 360 deg, 60 deg, 120 deg, 180 deg in this order due to the rotation of the rotating magnetic field. Change. Note that 360 deg is the same electrical angle as 0 deg.

  Normally, in the start-up operation, the rotor 10 is stopped or is rotating at a low speed before the start phase is energized. Therefore, a relatively large driving force is required at the time of energizing the start phase. Further, the driving force generated in the rotor 10 may be relatively small at the relative angle between the start phase and the rotor 10. In addition, there is a rotation direction position where the rotor 10 easily stops when the driving of the motor unit 1 stops. If this relative angle and the rotational direction position match, the starting success rate of the rotor 10 decreases. In the present embodiment, when the rotational position information is not synchronized with the rotation of the rotating magnetic field (NO in step S102), rotating magnetic fields having different start phases are generated and forced commutation is repeated. As a result, one of the starting phases coincides with the exciting phase that causes the rotor 10 to generate a large driving force. Therefore, it is possible to find the optimum start phase and improve the startup success rate of the rotor 10.

  In the forced commutation, all energization periods of the energization pattern are the same, and the rotating magnetic field rotates at a constant rotation speed. As a result, it is not necessary to make the energization period of the start phase, which requires a large driving force, longer than the energization period thereafter. Therefore, it is possible to reduce the power consumption during the startup operation.

  Further, in the start-up operation, only the forced commutation is performed without performing the DC excitation for positioning the rotor 10. As a result, the power consumption during startup operation can be further reduced.

  When the execution of the third forced commutation is completed, the number m of times of forced commutation is added once, and m = 3 is stored in the storage unit 43.

  When the rotational direction position information is not synchronized with the rotation of the rotating magnetic field during the third forced commutation (NO in step S102), it is determined in step S104 that the number m of times of forced commutation has reached three times. Yes (YES in step S104). At this time, the start-up operation is ended and the synchronous operation shown in FIG. 2 is not started. That is, when the rotating magnetic field is generated in the U-phase, V-phase, and W-phase starting phases and the motor unit 1 is not normally started, the motor unit 1 is normally started due to factors other than insufficient driving force. It is determined not to. Accordingly, when the rotor 10 does not rotate due to a factor other than insufficient driving force, it is possible to prevent the start-up operation from being stopped early and useless power consumption.

  In the next startup operation, in step S101, the rotating magnetic field of the same start phase as the previous one stored in the storage unit 43 is generated and forced commutation is performed. Thereby, the starting success rate of the rotor 10 can be improved in the first forced commutation of the starting operation. Therefore, the starting time of the motor unit 1 can be shortened.

(6. Other)
In the above, the present disclosure has described the exemplary embodiments. The scope of the present invention is not limited to the present disclosure. The present disclosure can be implemented with various modifications without departing from the spirit of the invention. Further, the items described in the present disclosure can be arbitrarily combined as long as no contradiction occurs.

  In the present embodiment, in the second forced commutation, the second excitation phase is set as the start phase by being shifted by 120 deg with respect to the start electrical angle of the first forced commutation. Alternatively, the third excitation phase may be shifted by −120 deg (240 deg) and used as the start phase. The start phase of the first forced commutation may be the second excitation phase or the third excitation phase. Further, when the first excitation phase is the start phase, the start electrical angle may be 60 deg.

  INDUSTRIAL APPLICABILITY The present disclosure is useful for a motor drive control device, a motor, and a blower device that sensorlessly controls a motor unit.

  100 ... Blower, 110 ... Impeller, 111 ... Blade, 120 ... Motor, 200 ... DC power supply, 1 ... Motor part, 10 ... Rotor, 11 ... Stator, 12 ... Phase winding, 12u ... U phase winding, 12v ... V phase winding, 12w ... W phase winding, 12c ... Point, 13u ... U phase Terminal, 13v ... V phase terminal, 13w ... W phase terminal, 3 ... Inverter, 3a ... Resistor, 31u, 31v, 31w ... Upper arm switch, 32u, 32v, 32w ... Lower arm switch, 4 ... Motor drive control device, 41 ... Drive control unit, 42 ... Current detection unit, 43 ... Storage unit, 44 ... Voltage detection unit, 45 ... Judgment unit , 46 ... Position information generation unit, 47 ... Rotation speed detection unit, Vu ... U-phase terminal voltage, Vv ... Phase terminal voltage, Vw ... W phase terminal voltage, Vn ... Virtual neutral point voltage, I ... Current value flowing in motor unit, I1 ... First current value, I2 ... Second Current value, CA ... Central axis, n ... Sequence

Claims (9)

A drive control unit that controls the drive of the motor unit by switching the energization pattern to the phase winding of the motor unit to which an AC voltage is applied in a predetermined order to generate a rotating magnetic field.
A voltage detector for detecting the voltage of the phase winding,
A position information generation unit that generates rotation direction position information in the rotation direction of the rotor of the motor unit based on the detection result of the voltage detection unit;
Equipped with
In the startup operation of the motor unit, the drive control unit performs forced commutation to generate the rotating magnetic field and forcibly rotate and drive the rotor, and the rotation direction position information indicates rotation of the rotating magnetic field. A motor drive controller that, when not synchronized, generates the rotating magnetic fields having different start phases and repeats the forced commutation. A three-phase AC voltage is applied to the motor unit,
In the start-up operation,
The motor drive control device according to claim 1, wherein when the rotation direction position information is not synchronized with the rotation of the rotating magnetic field, the starting electrical angle of the rotating magnetic field shifts by 120 degrees and the forced commutation is performed next time. In carrying out the forced commutation,
The motor drive control device according to claim 1, wherein the rotating magnetic field rotates at a constant rotation speed. In the start-up operation,
When the rotational direction position information is synchronized with the rotation of the rotating magnetic field, in the next startup operation, the rotating magnetic field having the same start phase as the previous time is generated to perform the forced commutation. Item 4. The motor drive controller according to any one of Items 3. Has a non-volatile storage,
The motor drive control device according to claim 4, wherein the start phase of the forced commutation is stored in the storage unit when the rotational direction position information is synchronized with the rotation of the rotating magnetic field. In the start-up operation,
The motor drive control device according to claim 1, wherein an upper limit value of the number of times of forced commutation is determined in advance.   The motor drive control device according to claim 6, wherein the number of executions is three.   A motor comprising the motor drive control device according to any one of claims 1 to 7. A motor according to claim 8;
An impeller having blades rotatable about a central axis extending in the up-down direction,
A blower.

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