JP2000184775A - Drive controller and control method for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive controller and control method for brushless motor in which sensorless drive control can be carried out even during high output operation. SOLUTION: Zero-cross point of each terminal voltage is detected from the terminal voltage of a plurality of stator windings 102u, 102v, 102w and an induction voltage zero-cross point, i.e., the zero-cross point in a section where the voltage induced in the stator winding through rotation of a permanent magnet rotor 103 is detected as a terminal voltage, is detected from the zero-cross point detection signal VU0, VV0, VW0 of each terminal voltage before phase switching of a current conducting through the stator winding 102u, 102v, 102w while being delayed by a specified electric angle from the induction voltage zero-cross point is controlled. Power being applied to stator winding for a specified time before the current conducting through the stator winding 102u, 102v, 102w is switched is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor for detecting the position of a magnetic pole of a rotor by detecting a zero crossing of an induced voltage induced in a stator winding, and switching from external synchronous control of starting to steady-state feedback control. And to a drive control method. In particular, the present invention relates to a drive control device and a drive control method for performing sensorless driving of a high-output, high-speed brushless motor.

[0002]

2. Description of the Related Art In recent years, in the trend of reducing the size and weight of various devices, it has been desired to reduce the size and weight of brushless motors for incorporating devices.

As a drive control device for driving such a brushless motor, a drive control device using a Hall IC is conventionally known. However, in a drive control device using a Hall IC or the like, the Hall IC must be mounted at a position where the magnetic pole position of the rotor can be detected, and there is a problem that the brushless motor becomes large and the number of wires increases. .

As one of the solutions, there is provided a brushless motor drive control device which detects a magnetic pole position of a rotor by detecting a zero cross of an induced voltage induced in a stator winding.

FIG. 14 is a block diagram showing the configuration of a conventional brushless motor drive control device.

In FIG. 14, reference numeral 101 denotes a stator of a brushless motor, 102u, 102v, and 102w denote three-phase connected stator windings for generating a driving magnetic field in the stator 101, and 103 denotes stator windings 102u, 102v, and 10w.
A permanent magnet rotor 104 driven to rotate by a magnetic field generated by 2w is a stator winding 102u, 102v, 102w.
Each terminal U, V, drive circuit for generating a connected drive current supplied to each stator winding W of, 105-110 are the stator windings 102u, 102v, the drive current i _u flowing through the 102w, i _v, i commutator element for switching _w , 1
11 to 116 are freewheeling diodes for releasing a surge voltage generated by switching of the commutator elements 105 to 110, 117 is a driving power supply for supplying a voltage for driving the stator 101, and 118 is superimposed on the voltage of the driving power supply 117. This is a bypass capacitor that removes noise.

The commutator elements 105 to 107 are NPN
Type transistors are used, and the commutator elements 108 to 108
Reference numeral 110 denotes a PNP transistor. One terminal O of the stator windings 102u, 102v, 102w is commonly connected, and the other terminal is a terminal U which is a common connection point of the commutator elements 105 and 108 (collector side of both elements).
The terminal V is connected to a common connection point (collector side of both elements) of the commutator elements 106 and 109, and the terminal W is connected to the commutator elements 107 and 110.
Are connected to the common connection point (collector side of both elements). The bypass capacitor 118 is connected to both electrodes of the drive power supply 117, and the negative side of the drive power supply 117 is grounded. The emitters of the commutator elements 105 to 107 are connected to the positive electrode of the drive power supply 117, and the collectors of the commutator elements 108 to 110 are grounded.

[0008] 119U, 119L is the stator winding 102
u, 102v, the potential of the neutral point of the voltage generated at terminal 102w (hereinafter, referred to as the neutral potential V _N.) Neutral potential generating resistor for generating, 120 stator windings 102u, 102
By comparing the terminal voltages V _U , V _V , V _W generated at the terminals U, V, W of v, 102 _w with the neutral potential V _N , zero-crossing point detection signals V _U0 , V _V0 , V _W0 are generated. The output zero cross point detectors 120u, 120v, and 120w receive terminal voltages V _U , V _V , and V _W and neutral potential V _{N, respectively,} and output zero cross point detection signals V _U0 , V _V0 , and V _W0. , 121 are control units for controlling the number of rotations of the permanent magnet rotor 103 by controlling the drive circuit 104.

One end of the neutral potential generating resistor 119U and one end of the neutral potential generating resistor 119L are connected to each other, and the other end of the neutral potential generating resistor 119U is connected to a bypass capacitor 11U.
8, and the other end of the neutral potential generating resistor 119L is grounded. The neutral potential generating resistor 119U and neutral potential generating resistor 119L, the resistance value so as to generate a neutral potential V _N is adjusted at the connection point O _R of each other are connected. Comparator 120u, 120v, the positive input side of 120w, respectively, terminals U, V, is connected to the W, each of the negative input side is connected to the connection point O _R. The control unit 121 is connected to the bases of the commutator elements 105 to 110, and controls the drive circuit 104 to control the six-phase control signals UH, UL, VH, VL, WH, WL.
Generate and output The control unit 121 is connected to outputs of the comparators 120u, 120v, and 120w. When the rotation speed of the permanent magnet rotor 103 becomes equal to or more than a certain value, the control unit 121 detects a zero-cross point detected by the zero-cross point detection unit 120. The control is switched to the feedback control for generating and outputting each six-phase control signal based on the signals V _U0 , V _V0 , V _W0 .

The operation of the conventional brushless motor drive control device configured as described above will be described below.

FIG. 15 is a diagram showing a time change of the terminal voltage of each stator winding in FIG. In FIG.
Are the zero-cross points of the terminal voltages V _U , V _V , V _W (neutral potential V _N
Is the point at which each terminal voltage V _U , V _V , V _W transitions from positive to negative or from negative to positive), B is each stator winding 102
This is a commutation point at which currents u, 102v, and 102w are commutated.

The control unit 121 controls the six-phase control signals UH, VH, WH, UL, and V each having a phase difference of 60 electrical degrees.
L and WL are generated. Commutator elements 105 to 110
Are switched by the six-phase control signals UH, VH, WH, UL, VL, WL.
02u, 102v, and 102w have a permanent magnet rotor 103
Drive currents i _u , i _v , i _w synchronized with the rotational movement of the permanent magnet rotor 103 to apply a rotational force to the permanent magnet rotor 103.

In such six-phase control, current is always supplied to two of the stator windings 102u, 102v, and 102w and the remaining one is released (105 and 1).
06, 107 and 108, 109 and 110 are both in the off state). An induced voltage generated by the rotation of the permanent magnet rotor 103 is generated at the terminals of the released stator windings 102u, 102v, 102w.
Therefore, the terminal voltages V _U , V _V , V _W have waveforms as shown in FIG.

[0014] Here, a description will be given of the waveform of the terminal voltage V _W applied to the stator winding 102w Examples, the interval P _1, the commutator element 110 is turned on, the commutator element 107 is turned off, the commutator element 105 or 1
06 is in the ON state, the commutator elements 109 and 108 are in the OFF state, and the drive current i _w is in the negative direction (three-phase connection portion O
From the terminal W to the terminal W), and the terminal voltage V _W is GN
Take a constant value of the potential (0 V) of D (potential of one terminal of the power supply). Further, in the section P _3, the commutator element 110 is turned off, the commutator element 107 is turned on, the commutator elements 105 and 106 are off, the commutator element 109 or 108 is in the ON state, the drive current i _w is a positive direction (terminal W to the three-phase connection portion O), and the terminal voltage V _W takes a constant value of the power supply voltage. In the section P ₂ and interval P _4, are both OFF state commutator elements 107 and 110, induced voltage appears at the terminals W.
At this time, the stator winding 1
Since in 02w of the magnetic field energy is accumulated in the first commutation point B of the section P ₂ and interval P _4, a surge voltage is generated in the stator winding 102w by switching of the commutator element 107 or 110. This surge voltage is released by surge current flows in the freewheeling diode 116 or 113, during which a voltage pulse for the switching before the opposite polarity occurs (section P ₅ and section P _6).

With respect to the waveforms of the terminal voltages V _u and V _v applied to the other stator windings 102 _u and 102 _v , the same waveform appears with a phase shift of 120 degrees in electrical angle from each other.

The control signal generator 120 is adapted to output the terminal voltage V
_u, V _v, of the waveform of the V _w, in the interval P ₂ and P ₄ induced voltage appears, the terminal voltages V _u, V _v, V _w the neutral potential V
_The three-phase control signal V _A synchronized with the rotation of the permanent magnet rotor 103 by detecting the zero-cross point A of the induced voltage and detecting the position of the permanent magnet rotor 103 in comparison with _n .
Generate and output V _B and V _C.

[0017]

However, in the above-described conventional brushless motor, the stator windings 102u, 102
When the currents flowing through v and 102w are large, the magnetic field energy accumulated in each stator winding is large, and the back electromotive force generated at the time of switching of the drive circuits 104 to 109 is large, and the discharge is performed through the commutator elements 110 to 115. The time required to release this back electromotive force becomes longer.

FIG. 16 is a diagram showing the time change of the terminal voltage of each stator winding in FIG. 14 when the driving current is large.

In FIG. 16, P _{1 to} P ₆ correspond to the sections denoted by the same reference numerals in FIG. 15, and B is a commutation point for commutating the current of each stator winding 102u, 102v, 102w. It is.

The stator windings 102u, 102v, 102w
When the current flowing through the commutator element 110 is large,
115 to discharge this back electromotive force.
Time to do P_FiveAnd P₆Becomes longer. On the other hand, the back electromotive force is permanent
It is generated corresponding to the position of the magnet rotor 103, and the commutation point B
Until the drive current is supplied to the next stator winding.
The polarity is reversed during that time. Discharge time P_FiveAnd P₆Is long, the reverse
Discharge does not end until the polarity of the electromotive voltage reverses,
The locross point A is a pulse of this back electromotive voltage (section P _Five) Hidden in
And cannot be detected. Therefore, permanent magnet
The position of the rotor 103 cannot be detected,
The problem that sensorless driving of a brushless motor cannot be performed
Had. In addition, the surge voltage generated during commutation is large.
The problem that the size affects the magnitude of the electromagnetic noise of the motor
Had.

A drive control apparatus for a brushless motor according to the present invention solves the above-mentioned conventional problems. The drive control apparatus suppresses a surge voltage, reduces electromagnetic noise of a motor, and has a large current flowing through a stator winding of the brushless motor. It is another object of the present invention to provide a brushless motor drive control device capable of detecting a zero-cross point generated in a stator winding and performing sensorless drive control.

A drive control method for a brushless motor according to the present invention solves the above-mentioned conventional problems. In the method, the surge voltage is suppressed, the electromagnetic noise of the motor is reduced, and the current flowing through the stator winding of the brushless motor is large. It is another object of the present invention to provide a brushless motor drive control method capable of detecting a zero-cross point generated in a stator winding and performing sensorless drive control.

[0023]

According to the present invention, there is provided a brushless motor drive control apparatus comprising: a plurality of stator windings connected at one point; and a magnetic field generated by each stator winding. A drive control device for a brushless motor, comprising: a permanent magnet rotor that is driven to rotate; a drive circuit that has a plurality of commutator elements and switches current supplied to a stator winding by switching each commutator element. And a zero-crossing point detection unit that detects a zero-crossing point from the terminal voltage of each stator winding and outputs a zero-crossing point detection signal corresponding to each of the stator windings, and a stator winding by rotating the permanent magnet rotor. An induced voltage zero-cross point, which is a zero-cross point in a section in which the induced voltage is detected as a terminal voltage, is extracted from each of the zero-cross point detection signals, and the induced voltage is zero-crossed. A feedback control signal generation unit that performs a phase change of each commutator element with a certain electrical angle delay from the point, and a stator winding between a certain time before the switching point where the commutator element is switched and the switching point. And an applied power control unit for performing control to suppress applied power.

With this configuration, even when the current flowing through the stator winding of the brushless motor is large, the electromagnetic noise of the motor is low, and a zero-cross point generated in the stator winding can be detected. It is possible to provide a possible brushless motor drive control device.

In order to solve the above problems, a drive control method for a brushless motor according to the present invention comprises a plurality of stator windings connected at one point, and a permanent magnet rotatably driven by a magnetic field generated by each stator winding. A drive control method for a brushless motor, comprising: a zero-cross point detection step of detecting a zero-cross point of each terminal voltage from terminal voltages of a plurality of stator windings; and fixing by rotating a permanent magnet rotor. The magnetic pole position detection process of extracting the induced voltage zero-cross point, which is the zero-cross point in the section where the induced voltage induced in the slave winding is detected as the terminal voltage, from the zero-cross point detection signal of each terminal voltage, and the constant from the induced voltage zero-cross point Current switching process for switching the phase of the current flowing through the stator winding with a delay of the electrical angle, and at a fixed switching point for switching the current flowing through the stator winding And suppressing applied power suppression process the power to be applied to the stator windings until switching point before, consisting configurations with.

With this configuration, even when the current flowing through the stator winding of the brushless motor is large, the electromagnetic noise of the motor is low, and a zero-cross point generated in the stator winding can be detected. A possible brushless motor drive control method can be provided.

[0027]

In order to achieve this object, a drive control device for a brushless motor according to a first aspect of the present invention comprises a plurality of stator windings connected at one point and a plurality of stator windings. A drive control device for a brushless motor, comprising: a permanent magnet rotor rotatably driven by a generated magnetic field, wherein the drive control device includes a plurality of commutator elements, and switches a current supplied to a stator winding by switching each commutator element. Circuit, a zero-cross point detection unit that detects the zero-cross point from the terminal voltage of each stator winding and outputs a zero-cross point detection signal corresponding to each of the stator windings, and is fixed by the rotation of the permanent magnet rotor The induced voltage, which is the zero-cross point in the section where the induced voltage induced in the slave winding is detected as the terminal voltage, is extracted from each zero-cross point detection signal and the induced voltage is derived. A feedback control signal generator for controlling the commutator elements to be phase-switched with a certain electrical angle delay from the locross point, and a stator winding for a predetermined time before the switch point at which the commutator elements are switched to the switch point And an applied power control unit for performing control to suppress the power applied to the power supply. The following operation is obtained by this configuration.

(1) In each phase, an induced voltage induced by the rotation of the permanent magnet rotor appears in the terminal voltage of the stator winding that is not energized. Also, at the switching point, the current flowing through the stator winding is commutated by the switching of the commutator element, and a back electromotive force is induced in the stator winding, and this back electromotive force is released through the freewheeling diode. Pulse is generated. The zero-cross point detector detects the zero-cross point of the induced voltage (the induced voltage zero-cross point) and the zero-cross point of the surge voltage pulse. The induced voltage zero crossing point is delayed from the switching point by a certain electrical angle (90 degrees for a single phase). At the switching point, the zero cross point of the surge voltage appears at the rising edge of the pulse, and then the zero cross point appears again at the falling edge of the pulse. The feedback control signal generator extracts the induced voltage zero-cross point from these zero-cross points, delays a certain electrical angle from the induced voltage zero-cross point, switches the phases of the commutator elements, and feeds back the rotational position of the permanent magnet rotor. Perform phase switching control.

(2) The applied power control section controls the magnetic field accumulated in the stator winding at the switching point in order to suppress the power applied to the stator winding from a predetermined time before the switching point to the switching point. Energy is suppressed. Therefore, even when the current flowing through the stator winding is large, such as a high-output, high-speed brushless motor, the back electromotive force induced in the stator winding at the switching point is suppressed, and the pulse width of the surge voltage is reduced. Decrease. As a result, the release of the surge voltage is completed before the zero-cross point of the induced voltage, the surge voltage pulse is prevented from being superimposed on the zero-cross point of the induced voltage, and the feedback control signal generation unit detects the zero-cross point of the induced voltage. And the phase switching control of the commutator element by feeding back the rotational position of the permanent magnet rotor becomes possible.

(3) Since the pulse width of the surge voltage is narrow, it is possible to reduce electromagnetic noise during phase switching.

Here, as a method of suppressing the electric power applied to the stator winding, a method of reducing the driving current applied to the stator winding or a method of performing pulse width modulation on the driving current applied to the stator winding is described. Are used.

Further, the applied power control unit is based on the zero-cross point of the induced voltage extracted by the feedback control signal generation unit or the zero-cross point due to a surge voltage pulse generated in any of the stator windings at the switching point. Control is performed to suppress the power applied to the stator windings from a point delayed by a certain time from that point to the next switching point.

According to a second aspect of the present invention, there is provided a drive control device for a brushless motor according to the first aspect,
A current detection unit that detects a total current value or a phase current value supplied to the stator winding is provided, and the applied power control unit detects the total current value or the phase current value detected by the current detection unit, or an average value or an average value thereof. The configuration is such that the amount of suppression of the power applied to each stator winding is determined based on the effective value.With this configuration, the applied power control unit controls the total current value or the phase current value or The suppression amount of the power applied to each stator winding can be optimized based on the average value or the effective value, and the effect that the power efficiency of the brushless motor is improved can be obtained.

Here, the applied power control unit performs A / D conversion of the output of the current detection unit, and adjusts the magnitude and time of the applied power to be reduced, which is the suppression amount of the applied power, according to the value and the magnitude. To determine.

According to a third aspect of the present invention, there is provided a drive control device for a brushless motor according to the first aspect,
A current detection unit that detects the total current value or phase current value supplied to the stator winding, and a total current value or phase current value detected by the current detection unit, or an average value or an effective value thereof, is a certain value. An applied power suppression determination unit that performs a determination of permitting suppression of applied power to each stator winding when the applied power is large, wherein the applied power control unit is permitted to suppress applied power by the applied power suppression determination unit. And a control for suppressing the power applied to each stator winding a predetermined time before the switching point, and the configuration is such that the applied power suppression determination unit is a current detection unit. Since the power applied to the stator winding is suppressed only when the detected total current value or phase current value or their average value or effective value is larger than a certain value, the brushless motor is driven at low output and low rotation. When driving Effect that the efficiency is improved is obtained.

According to a fourth aspect of the present invention, there is provided the drive control apparatus for a brushless motor according to any one of the first to third aspects, wherein the applied power control unit is provided with a predetermined time before the switching point. In this configuration, control is performed to suppress the base voltage applied to each commutator element.
The following operation is obtained.

(1) The driving power supplied to the stator winding is suppressed by the applied power control unit suppressing the base voltage applied to each commutator element a predetermined time before the switching point.

(2) Since the suppression is not performed by the ON / OFF control, electric noise at the time of suppression can be reduced.

According to a fifth aspect of the present invention, there is provided a drive control device for a brushless motor according to any one of the first to third aspects, wherein a base voltage of each commutator element or a voltage applied to a drive circuit. A pulse width modulation unit that performs pulse width modulation, and the applied power control unit controls pulse width modulation of the base voltage applied to each commutator element or the voltage applied to the drive circuit by a pulse width modulation unit by a pulse width modulation unit for a predetermined time before the switching point. This configuration is characterized in that the following operations are obtained.

(1) The power applied to each stator winding is suppressed by the applied power control unit performing pulse width modulation of the base voltage of each commutator element or the voltage applied to the drive circuit a fixed time before the switching point. Is done.

(2) Commutator loss is small due to pulse width modulation (ON / OFF). (3) The structure is simple, and the amount of suppression of the applied power can be smoothly controlled.

Here, the applied power control unit starts switching from the arbitrary point t3 between the time when the induced voltage zero crossing point t2 is first detected after the switching point t1 and the next switching point t4 to the switching point t
For up to 4, it is preferable to control the base voltage applied to each commutator element or the voltage applied to the drive circuit to be pulse width modulated by the pulse width modulation unit. From an arbitrary point t3 ′ between the switching point t1 and the induced voltage zero crossing point t2 to a switching point t4, the base voltage applied to each commutator element or the voltage applied to the drive circuit is pulse width modulated by the pulse width modulator. With such control, the feedback control signal generator needs to remove the PWM pulse in order to extract the induced voltage zero crossing point t2.

According to a sixth aspect of the present invention, there is provided a drive control device for a brushless motor according to any one of the first to third aspects, wherein a variable output voltage for supplying a voltage to be applied to a drive circuit. A current source having a variable output that supplies a current to be applied to the source or the drive circuit, and the applied power control unit suppresses a voltage that the voltage source applies to the drive circuit or a current that the current source applies to the drive circuit a predetermined time before the switching point In this configuration, the applied power control unit controls the voltage applied by the voltage source to the drive circuit or the current applied by the current source to the drive circuit a predetermined time before the switching point. The effect of suppressing the driving current supplied to the stator winding is obtained.

According to a seventh aspect of the present invention, there is provided a drive control device for a brushless motor according to the sixth aspect, wherein:
The applied power control unit is configured to perform control to lower the voltage applied to the drive circuit or the current applied to the drive circuit by a voltage approximating a sine wave by the voltage source a predetermined time before the switching point. Yes, with this configuration,
The following operation is obtained.

(1) The applied power control unit responds to a change in the magnetic flux density created inside the stator winding by the permanent magnet rotor,
The voltage applied to the drive circuit by the voltage source or the current applied by the current source to the drive circuit a certain time before the switching point is suppressed, whereby the reduction in the power efficiency of the brushless motor is suppressed, and the voltage is supplied to the stator winding. Driving current is suppressed.

(2) The surge voltage hardly occurs, and the zero-cross point can be reliably detected.

(3) No electromagnetic noise due to the surge voltage is generated. A drive control method for a brushless motor according to claim 8 of the present invention includes a plurality of stator windings connected at one point, a permanent magnet rotor that is rotationally driven by a magnetic field generated by each stator winding, A drive control method for a brushless motor, comprising: a zero-cross point detection process of detecting a zero-cross point of each terminal voltage from terminal voltages of a plurality of stator windings; and a stator winding by rotation of a permanent magnet rotor. A magnetic pole position detection process of extracting an induced voltage zero-cross point, which is a zero-cross point in a section where an induced voltage is detected as a terminal voltage, from a zero-cross point detection signal of each terminal voltage, and a fixed electrical angle delay from the induced voltage zero-cross point Current switching process for switching the phase of the current supplied to the stator winding and switching the current supplied to the stator winding from a predetermined time before the switching point to the switching point. And suppressing applied power suppression process the power to be applied to the stator winding, which has a structure provided with, this configuration the following effects are obtained.

(1) In each phase, an induced voltage induced by the rotation of the permanent magnet rotor appears in the terminal voltage of the stator winding that is not energized. Also, at the switching point, the current flowing through the stator winding is commutated, and a back electromotive force is induced in the stator winding, and a surge voltage pulse is generated by the back electromotive force. Therefore, in the zero-cross point detection process,
For each terminal voltage, the zero-cross point of the above-mentioned induced voltage (the zero-cross point of the induced voltage) and the zero-cross point of the surge voltage pulse are detected. The induced voltage zero cross point is delayed from the switching point by a certain electrical angle. At the switching point, the zero cross point of the surge voltage appears at the rising edge of the pulse, and then the zero cross point appears again at the falling edge of the pulse. In the magnetic pole position detection process, an induced voltage zero cross point is extracted from these zero cross points. afterwards,
In the current switching process, the commutator elements are phase-switched with a certain electrical angle delay from the induced voltage zero crossing point, thereby performing phase switching control in which the rotational position of the permanent magnet rotor is fed back.

(2) In the applied power suppressing process, the magnetic field accumulated in the stator winding at the switching point is controlled in order to suppress the power applied to the stator winding from a predetermined time before the switching point to the switching point. Energy is suppressed. Therefore, even when the current flowing through the stator winding is large, such as a high-output, high-speed brushless motor, the back electromotive force induced in the stator winding at the switching point is suppressed, and the pulse width of the surge voltage is reduced. Decrease. As a result, the release of the surge voltage is completed before the zero-cross point of the induced voltage, the pulse of the surge voltage is prevented from being superimposed on the zero-cross point of the induced voltage, and the zero-cross point of the induced voltage is detected in the zero-cross point detection process. And the phase switching control of the commutator element by feeding back the rotational position of the permanent magnet rotor becomes possible.

(3) The circuit for detecting the magnetic pole position of the stator itself becomes unnecessary. Here, as a method of suppressing the power applied to the stator winding, a method of reducing the driving current applied to the stator winding, a method of performing pulse width modulation of the driving current applied to the stator winding, or the like is used. Can be

In the applied power suppressing step, the induced voltage zero crossing point extracted in the magnetic pole position detecting step or the zero crossing point due to a surge voltage pulse generated in any stator winding at the switching point is used as a reference. Control is performed to suppress the power applied to the stator windings from the point delayed by a certain time from the point to the next switching point.

According to a ninth aspect of the present invention, there is provided a drive control method for a brushless motor according to the eighth aspect, wherein:
A current detecting step of detecting a total current value or a phase current value supplied to the stator winding, and in the applied power suppressing step, a suppression amount of power applied to each stator winding is detected by the current detecting step. The characteristic is determined based on the total current value or the phase current value or the average value or the effective value thereof. With this configuration, the total current value or the phase current value or the average value or the effective value thereof is obtained. It is possible to optimize the amount of power applied to each stator winding based on the value, and to obtain the effect of improving the power efficiency of the brushless motor.

According to a tenth aspect of the present invention, in the drive control method for a brushless motor according to the eighth aspect, a current for detecting a total current value or a phase current value supplied to the stator winding is provided. The detection process and the determination of permitting the suppression of the power applied to each stator winding when the total current value or phase current value detected in the current detection process or their average value or effective value is larger than a certain value. Performing an applied power suppression determination step, and the applied power suppression step includes, when suppression of the applied power to each stator winding is permitted in the applied power suppression determination step, from a predetermined time before the switching point to the switching point. During this period, the power applied to each stator winding is suppressed, and this configuration allows the total current value or the phase current value detected by the current detection unit, or the average value thereof. Or there is an effective value Power suppression applied only to the stator windings when value is greater than is done, thereby the action that the power efficiency in the case of operating the brushless motor at low output and low-speed is improved is obtained.

According to an eleventh aspect of the present invention, in the drive control method for a brushless motor according to any one of the eighth to tenth aspects, the applied power suppressing step is performed a predetermined time before the switching point. In this configuration, the power applied to the stator winding is reduced by a waveform approximating a sine wave, and the following operation is obtained by this configuration.

(1) The power applied to the stator windings a predetermined time before the switching point is suppressed in accordance with the change in the magnetic flux density created inside the stator windings by the permanent magnet rotor. The reduction in the power efficiency of the motor is suppressed, and the drive current supplied to the stator winding is suppressed.

(2) The surge voltage hardly occurs, and the zero-cross point can be reliably detected.

(3) Generation of electromagnetic noise due to surge voltage can be prevented. According to a twelfth aspect of the present invention, there is provided the drive control method for a brushless motor according to any one of the eighth to tenth aspects, wherein the applied power suppressing step is performed such that each fixed power supply is fixed before a switching point. This configuration is characterized in that the voltage applied to each of the stator windings is pulse width modulated before the switching point for a certain period of time. Thus, the effect of suppressing the power applied to each stator winding is obtained.

Here, in the applied power suppressing process, after an induction voltage zero crossing point t2 is first detected after the switching point t1, an arbitrary point t3 between the next switching point t4 and
Until the switching point t4, the voltage applied to each stator winding is preferably subjected to pulse width modulation. Pulse width modulation of the voltage applied to each stator winding from an arbitrary point t3 ′ between the switching point t1 and the induced voltage zero crossing point t2 to the switching point t4 extracts the induced voltage zero crossing point t2. Therefore, a process for removing the PWM pulse is required.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a device configuration of a drive control device for a brushless motor according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 101 denotes a stator;
u, 102v, 102w are stator windings, 103 is a permanent magnet rotor, 104 is a drive circuit, 105 to 110 are commutator elements, 111 to 116 are freewheeling diodes, 117 is a drive power supply, 118 is a bypass capacitor, 120 Denotes a zero-crossing point detector, 120u, 12
Reference numerals 0v and 120w denote comparators, which are the same as the conventional ones.

119u, 119v, 119w, 119N
Stator windings 102u is, 102v, the potential of the neutral point of the voltage generated at terminal 102w (hereinafter, referred to as the neutral potential V _N.) Neutral potential generating resistor for generating, R _I is the total current value detected _{resistance, R UH1 ~R UHn, R VH1} ~R VHn, R WH1 ~R WHn,
R _{UL1 to} R _ULn , R _{VL1 to} R _VLn , and R _{WL1 to} R _WLn are commutator elements 105, 106, ₁₀₇ , ₁₀₈ , 1 respectively.
A base voltage setting resistor for setting the base voltages of 09 and 110, and a control unit 121 for controlling the rotation speed of the permanent magnet rotor 103 by controlling the drive circuit 104.

In the present embodiment, the emitters of the commutator elements 108 to 110 are connected to the total current value detection resistor R _I.
Grounded. Further, the neutral potential generating resistor 11
9u, 119V, 119W is connected at one end at the connection point O _R, respectively the other end, the neutral potential generating resistor 1
19u is connected to terminal U, and neutral potential generating resistor 119v is connected to terminal V.
The neutral potential generating resistor 119w is connected to the terminal W. One end of the neutral potential generating resistor 119N is connected to a connection point O.
_R and the other end is grounded. Neutral potential V _N is obtained at the connection point O _R, the connection point O _R is comparators 120u, 120v, and is connected to the negative input of 120 w. Base voltage setting resistor _{R UH1 ~R U Hn, R VH1} ~
R _VHn , R _{WH1 to} R _WHn , R _{UL1 to} R _ULn , R _{VL1 to} R _VLn ,
One end of each of R _{WL1 to} R _WLn is a commutator element 1
05, 106, 107, 108, 109 and 110 are connected to the base, and the other end is connected to each output terminal of the control unit 121. The control section 121 is connected to the bases of the commutator elements 105 to 110 via these base voltage setting resistors, and controls the six-phase control signals UH, UL, VH, VL, WH, W for controlling the drive circuit 104.
Generate and output L. The control unit 121 is connected to outputs of the comparators 120u, 120v, and 120w. When the rotation speed of the permanent magnet rotor 103 becomes equal to or more than a certain value, the control unit 121 detects a zero-cross point detected by the zero-cross point detection unit 120. The control is switched to the feedback control for generating and outputting each six-phase control signal based on the signals V _U0 , V _V0 , V _W0 .

FIG. 2 is a block diagram showing a functional configuration of the control unit of FIG. 2, reference numeral 131 denotes a drive circuit 1
An external synchronization control unit 132 that generates and outputs external synchronization three-phase control signals V _Ai , V _Bi , and V _Ci that are three-phase control signals for controlling the switching of the drive current 04, and 132 is input from the zero-cross point detection unit 120. _Zero- crossing point detection signals V _U0 , V
_V0, three-phase control signals at a feedback three phase control signal V _Af synchronized with the rotation of the permanent magnet rotor 103 based on V _W0, V _Bf, V
_The feedback three-phase control signal generator 133 for generating _Cf outputs the permanent magnet rotor 103 based on the interval of the zero-cross point of the induced voltage generated in each stator winding detected and output by the feedback three-phase control signal generator 132. Is a rotation speed detection unit that detects the rotation speed N of the motor.

The feedback three-phase control signal generator 132 _{converts the} zero-cross point detection signals V _U0 , V _V0 , V _W0 from the zero-cross point of the induced voltage generated at the terminals U, V, W by the rotation of the permanent magnet rotor 103. corresponding points a in FIG. 15) and detects the edge of a surge voltage pulses, each phase of the induced voltage zero cross point detection signal V _Z and each phase of the zero-crossing point of the induced voltage to notify that it has been detected in any with surge pulse edge in either generates an edge detection signal V _s to notify that it has been detected, the detected electrical angle 30 degree delay to the feedback three-phase control for inverting the zero cross point of the induced voltage in each phase The signals V _Af , V _Bf and V _Cf are generated. Speed detecting section 133 measures the time interval of the induced voltage zero cross point detection signal V _Z, calculates the rotational speed N of the permanent magnet rotor 103 at each time point.

When the rotational speed N detected by the rotational speed detector 133 is equal to or less than a certain value, the external synchronous three-phase control signals V _Ai , V _Bi and V _Ci are converted from the rotational speed N to a certain value. If so a three-phase control signal switching section for performing feedback three-phase control signal V _Af, V _Bf, V _Cf three-phase control signals V _a, V _B, the switching control so as to output as V _C.

Reference numeral 135 denotes a six-phase control signal UH ₀ , VH ₀ , WH ₀ , UL ₀ , V which switches the commutator elements 105 to 110 based on the three-phase control signals V _A , V _B , V _C.
This is a six-phase control signal generator that generates and outputs L ₀ and WL ₀ . 136 current detection unit for detecting a current value I supplied to the drive circuit 104 from the total current detection signal V _I, which is the voltage across the total current value detection resistor R _I, 137 denotes a current detection unit 1
Based on the current value I detected at 36, the stator winding 102
The applied power suppression determination unit 138 that performs a threshold determination as to whether or not to suppress the power applied to u, 102v, and 102w, when the applied power suppression determination unit 137 determines that the applied power is to be suppressed, the commutator elements 105 to 105 A base voltage control unit 139 that controls switching of the base voltage of 110
Is a base voltage switching unit that switches the base voltage of the commutator elements 105 to 110 under the control of the base voltage control unit 138.

[0067] applying power restriction judging unit 137, the rise of the surge pulse of induced voltage from the edge detection signal V _s (hereinafter, referred to as a commutation point.) Is detected, is detected by the current detecting section 136 immediately before The current value _If is compared with the threshold value I ₀ and the threshold value I ₁ (I ₀ > I ₁ ), and the current value _If is set to the threshold value I ₁
Is smaller than is disallowed the control for suppressing the base voltage, the current value I _f is the case of more than the threshold value I ₀ permits the control for suppressing the base voltage. When the control to suppress the base voltage is permitted by the applied power suppression determination unit 137, the base voltage control unit 138 outputs the current detection unit 136.
From the current value _If immediately before the commutation point detected by
The amount of suppression of the base voltage is determined, and the time from the commutation point to the next commutation point is predicted based on the rotation speed N detected by the rotation speed detection unit 133. performing suppression of the base voltage by switching the voltage switching signal V _b1 ~V _bn. Base voltage switching section 139, 6 × n pieces of logical and an arithmetic unit, the output of the logical AND operation of each base voltage setting resistor _{R UH 1 ~R UHn, R VH1} ~R VHn, R
_{WH1 ~R WHn, R UL1 ~R ULn} , R VL1 ~R VLn, R WL1 ~R
Connected to _WLn . Base voltage setting resistors R _{UH1 to} R
_UHn includes a six-phase control signal UH ₀ and a base voltage switching signal V _b1 .
Is logical product signal of the positive logic input and V _bn, base voltage setting resistor R _VH1 to R _VHn six phase control signal VH ₀ and the base voltage switching signal V _{b 1} ~V _bn and the positive logic of the logical product signal to There is inputted, the base voltage setting resistor R _WH1 to R _Whn is input positive logic aND signal of the six phase control signal WH ₀ and the base voltage switching signal V _b1 ~V _bn, base voltage setting resistor R _UL1 ~ R _ULn
Six phase control signal UL ₀ and the base voltage switching signal V _b1 ~V in
positive logic AND signal of the _bn are inputted, the base voltage setting resistor R _VL1 to R _VLn positive logic AND signal of the six phase control signal VL ₀ and the base voltage switching signal V _b1 ~V _bn to the input is, the base voltage setting resistor R _WL1 to R _WLn positive logic aND signal of the six phase control signal WL ₀ and the base voltage switching signal V _b1 ~V _bn is inputted. Base voltage setting resistors R _UHi , R
_{VHi, R WHi, R ULi,} R VLi, R WLi (i = 1,2, ··
., N) have the same resistance value when the index i is the same, and the resistance value increases as the index i increases. Six-phase control signals UH ₀ , UL ₀ , VH ₀ , V
L ₀ , WH ₀ , WL ₀ are base voltage setting resistors R _UHi , R _{UHi
VHi, R WHi, R ULi,} R VLi, R WLi (i = 1,2, ··
, N), and the six-phase control signals UH, U
Commutator element 1 as L, VH, VL, WH, WL
And output to 05-110. Voltage drop base voltage setting resistor _{R UHi, R VHi, R WHi} , R U Li, R VLi, R WLi (i =
1, 2,..., N), the base voltage control unit 138 switches the base voltage switching signals V _{b1 to} V _bn to select one of the base voltage setting resistors, thereby making the commutator element. It is possible to control the base voltages of 105 to 110.

The control method of the drive control apparatus for a brushless motor according to the present embodiment having the above-described configuration will be described below.

When the brushless motor is started, the three-phase control signal switching unit 134 converts the external synchronization three-phase control signals V _Ai , V _Bi , and V _Ci generated by the external synchronization control unit 131 into three-phase control signals V _A and V _B. , V _C , and the brushless motor is driven in a state where external synchronous control is performed (hereinafter, referred to as an external synchronous control state). At this time, the current detector 136
Continue to detect the total current value supplied to the drive circuit 104. When the rotation speed increases and the induced voltage due to the rotation of the permanent magnet rotor 103 becomes large enough to be detected by the zero-cross point detection unit 120, the feedback three-phase control signal generation unit 132
Starts to output an induced voltage zero cross point detection signal V _Z and edge detection signal V _s. When the edge detection signal V _s is inputted, applied power restriction judging section 137 compares the current value I _f and the threshold I ₀ detected by the current detecting section 136 immediately before the commutation points, the current value I _f When it is larger than the threshold value I _0, control for suppressing the applied voltage is permitted. At this time, in the initial state, it is assumed that the control for suppressing the applied voltage is in a non-permitted state. When the control to suppress the applied voltage is permitted by the applied power suppression determination unit 137, the base voltage control unit 1
38, by selecting based on the detected current value I _f by the current detecting section 136 immediately before the commutation point, the base voltage switching signal to be output from the V _b1 ~V _bn, how much base voltage Decide whether to suppress. At the same time, the base current is switched before commutation, and the stator winding 10 is switched before commutation.
Control is performed to suppress the current value flowing through 2u, 102v, and 102w.

When the rotation speed N of the permanent magnet rotor 103 detected by the rotation speed detection unit 133 exceeds a certain value, the three-phase control signal switching unit 134 sends an input to the feedback three-phase control signal generation unit 132. Switching, feedback three-phase control signal V _Af ,
V _Bf and V _Cf are output to the six-phase control signal generator 135 as three-phase control signals V _A , V _B and V _C to enter a feedback control state. At this time, the stator windings 102u, 102v, 1
Since the value of the current flowing through 02w is suppressed before commutation, it is possible to prevent the pulse width of the surge voltage from being wide as shown in FIG. 16 so that the zero cross point is not detected.

Next, the switching operation of the base voltage by the control unit will be described in more detail. FIG. 3 is a flowchart showing the switching operation of the base voltage of the control unit in FIG. 1, and FIG. 4 is a diagram showing the time change and timing of each signal in FIG. In FIG. 4, A is a zero crossing point of an induced voltage generated at terminals U, V and W, and B is each stator winding 102.
commutation point for commutating the current of u, 102v, 102w, C
Is a base voltage switching point at which the base voltage is switched.

[0072] First, applying power restriction judgment unit 137 detects the commutation point from the edge detection signal V _s (S101).

When the commutation point is detected, the base voltage is set to a steady value (a value when the base voltage is not suppressed) (S102), and the base voltage control unit 138 sets the count value t of the internal timer. Is reset to 0, and the timer starts counting (S103).

The applied power suppression judging section 137 outputs the current value I _f detected by the current detecting section 136 immediately before the commutation point.
Is compared with the threshold value I ₀ and the threshold value I ₁ (I ₀ > I ₁ ) (S104). The applied power suppression determination unit 137 calculates the current value I
If _f is less than the threshold I _1, the process returns to step S101 and disallow control for suppression of the base voltage, when the current value I _f is not less than the threshold value I ₀ is a control for suppressing the base voltage To give permission. When I ₁ <I _f <I ₀ , the current permission or non-permission state is maintained, and the process returns to step S101 (S1).
05).

When the control to suppress the base voltage is permitted by the applied power suppression determination unit 137, the base voltage control unit 138 determines the amount of suppression of the base voltage from the current value _If , and determines the amount of suppression of the base voltage. selecting a signal output from the base voltage switching signal V _b1 ~V _bn. Determining therewith, to predict the time T from the commutation point to the next commutation point by the rotational speed N detected by the rotation speed detector 133, the time t ₁ from the commutation point to keep the base voltage ( For example, t ₁ =
Determined as 0.8T. However, 0.5T <t ₁ <T) to (S106).

Next, the base voltage control section 138 waits until the count value t of the timer becomes t ₁ or more (S10).
7), switch the base voltage when the count value t becomes t ₁ timer and suppresses base voltage (S10
8).

Thereafter, the flow returns to step S101 again to repeat the same operation. At this time, the waveforms of the signals of the respective parts in FIG. 1 are as shown in FIG.

The six-phase control signals UH, UL, which are the base voltages of the commutator elements 105 to 110,
VH, VL, WH, WL are switched and suppressed at the base voltage switching point C.

Thus, the stator windings 102u, 102
v, 102 w, the current value at the commutation point B is suppressed, and the stator winding 102 at the commutation point is reduced.
The magnetic field energy in u, 102v, 102w decreases. Therefore, at the commutation point B, the commutator elements 105 to 11
The pulse width of the surge voltage generated when performing a switching of 0 decreases, the terminal voltage V _U, V _V, it is possible to detect the zero-cross point A of the V _W (V _U in FIG. 4, V _V, V _W ).

At the commutation point B, the six-phase control signals UH, U
L, VH, VL, WH, WL are switched and returned to the original voltage values again.

[0081] At this time, the total current detection signal V _I, which is the voltage generated at both ends of the total current value detection resistor R _I is as shown in FIG. Applying power restriction determination unit 137, by detecting the value of the total current detection signal V _I at point D immediately before the commutation points by commutator element 106, the commutation point B
_Are detected immediately before the current value is detected.

In the present embodiment, the timing for suppressing the base voltage is determined as the time when the rising of the surge voltage pulse (commutation point B) is used as a trigger to start the timer and delay by a certain time. Alternatively, the timer may be started with the falling edge of the surge voltage pulse (point E in FIG. 4) or the zero-cross point A as a trigger, and may be determined as a point in time delayed by a certain time.

In the present embodiment, applied power suppression determination section 137 detects total current value _If immediately before commutation point B, and determines whether or not to apply applied power before the next commutation point. Although the permission is determined, the applied power suppression determination unit 137 determines
Current detector 136 during the edge detection signal V _s from the previous commutation points for each commutation point is detected until the commutation point
Average value _Iev or effective value I of all current values detected by
_eff may be calculated, and the value may be used to determine whether to permit or prohibit the suppression of the applied power before the next commutation point.
Further, in this case, the base voltage control unit 138 is configured to determine the suppression amount of the base voltage based on the average value I _ev or the effective value I _eff of all the current values calculated by the applied power suppression determination unit 137. Is also good. As a result, the influence of noise is reduced, malfunction is prevented, and the zero-cross point can be reliably detected.

(Embodiment 2) FIG. 5 is a block diagram showing a device configuration of a drive control device for a brushless motor according to Embodiment 2 of the present invention.

In FIG. 5, reference numeral 101 denotes a stator;
u, 102v, 102w are stator windings, 103 is a permanent magnet rotor, 104 is a drive circuit, 105 to 110 are commutator elements, 111 to 116 are freewheeling diodes, 117 is a drive power supply, 118 is a bypass capacitor, and 119U And 119L are neutral potential generation resistors, 1
Reference numeral 20 denotes a zero cross point detection unit, 120u, 120v, and 12
0w is a comparator, which is the same as the conventional one, and therefore, is denoted by the same reference numeral and description thereof is omitted. UH, UL, VH, VL, WH, WL, UH ₀ , U
L ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ are six-phase control signals,
i _u , i _v , i _w are drive currents, V _U , V _V , V _W are terminal voltages,
V _U0 , V _V0 , and V _W0 are zero-cross point detection signals, which are the same as those in the first embodiment, and are denoted by the same reference numerals and description thereof is omitted.

105a to 110a are commutator elements 1
A switching circuit for performing switching from 05 to 110, a control unit 121 for controlling the rotation speed of the permanent magnet rotor 103 by controlling the drive circuit 104.

Control unit 121 controls six-phase control signals UH ₀ , UL ₀ , VH ₀ , and VH for controlling drive circuit 104.
L ₀ , WH ₀ , WL ₀ are generated and output. Control unit 1
Reference numeral 21 is connected to the output side of the comparators 120u, 120v, and 120w, and when the rotation speed N of the permanent magnet rotor 103 exceeds a certain value, the zero-cross point detection unit 1
The zero-crossing point detection signals V _U0 , V _V0 ,
_Switching to feedback control for generating and outputting each six-phase control signal based on VW0.

Reference numeral 141 denotes commutator elements 105 to 110
Pulse width modulator 14 for pulse width modulating the base voltage of
2 is an F / V converter, 143 is an oscillator that oscillates and outputs a rectangular wave, 144 is an integration circuit that shapes and outputs a rectangular wave output from the oscillator 143 into a triangular wave, and 145 is an output and integration circuit of the F / V converter 142. comparator for outputting a PWM signal V _PWM compares 144 the output of 146～
151 is a six-phase control signal UH ₀ , UL ₀ , VH ₀ ,
Pulse width modulated six-phase control signals UH, U which are the logical product of the positive logic of VL ₀ , WH ₀ , WL ₀ and the PWM signal V _PWM
A modulation unit that generates and outputs L, VH, VL, WH, and WL;
R _IU , R _IV , and R _IW are commutator elements 108,
A phase current detection resistor for detecting a phase current flowing through 109 and 110.

The six-phase control signals UH ₀ , U
The output terminals of L ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ are connected to one input side of the modulation units 146, 147, 148, 149, 150, 151, and the output of the comparator 145 is the modulation unit 146, 147, 148, 149, 150, 15
1 is connected to the other input side. The collector sides of the commutator elements 108 to 110 are grounded via phase current detection resistors R _IU , R _IV , and R _IW , respectively. Phase current detection resistors R _IU , R _IV , R _IW and commutator element 10
Common connection points with the collectors 8 to 110 are connected to the control unit 121. The input side of the F / V converter 142 is connected to the control unit 121, and the output side of the F / V converter 142 is connected to the positive input side of the comparator 145.
F / V converter 142 converts the PWM control signal V _P which is input from the control unit 121 into a voltage signal, and outputs to the comparator 145. The input side of the comparator 145 is connected to the integrating circuit 144, and the comparator 1
45 generates a PWM signal V _PWM by comparing a voltage signal input from the F / V converter 142 with a triangular wave input from the integration circuit 144, and modulates the modulation units 146 to 151.
Output to

FIG. 6 is a block diagram showing the functional configuration of the control unit shown in FIG.
FIG. 6, reference numeral 121 denotes a control unit;
Is an external synchronization control unit, 132 is a feedback three-phase control signal generation unit,
133 is a rotation speed detecting unit, 134 is a three-phase control signal switching unit,
135 is a six-phase control signal generator, 136 is a current detector, 1
37 is an applied power suppression determination unit, _Ai, V_Bi, V_CiIs external
Three-phase control signal, V_Af, V_Bf, V_CfIs the feedback three-phase control signal
No., V_A, V_B, V_CIs a three-phase control signal, UH₀, UL₀, V
H₀, VL₀, WH₀, WL₀Is the six-phase control signal, V_ZIs induction
Voltage zero crossing point detection signal, V_sIs the edge detection signal, V_p
Are PWM control signals, which are the same as in FIGS. 2 and 5.
Therefore, the same reference numerals are given and the description is omitted.

However, the current detecting section 136 has a phase current detecting resistor.
Anti-R_IU, R_IV, R_IWCurrent detection signal V, which is the voltage across
_IU, R_IV, R_IWFrom the commutator elements 108, 109,
A phase current passing through 110 is detected. In addition, applied power suppression
The suppression determination unit 137 outputs the edge detection signal V_sMore induced voltage
The rise of the surge pulse (hereinafter called the commutation point)
When detected, the current detector 136 immediately before the commutation point
Detected phase current value I _fUOr I_fVOr I_fWValue and threshold
Value I₀And threshold I₁(I₀> I₁) And the phase current value I
_fUOr I_fVOr I_fWIs the threshold I₁If less than
Indicates that the control to suppress the applied power is not permitted and the phase current value
I_fUOr I_fVOr I_fWIs the threshold I₀In the above cases,
Control to suppress the applied power is permitted.

161 is an applied power control unit, and 162 is a PWM
It is a control unit. When the control to suppress the applied power is permitted by the applied power suppression determination unit 137, the applied power control unit 161 determines the phase current value _IfU or _IfVV immediately before the commutation point detected by the current detection unit 136. Alternatively, the amount of suppression of the applied power is determined from I _fW , the time from the commutation point to the next commutation point is predicted based on the rotation speed N detected by the rotation speed detection unit 133, and the next commutation point is determined. the applied power switching signal S _Q predetermined time before performing the suppression of the applied power by outputting the PWM control unit 162. PWM control unit 162, the applied power switching signal S _Q is input, based on the suppression of applied power determined by applying the power control unit 161 outputs a PWM control signal V _p to F / V converter 142 . F / V converter 142 outputs to the comparator 145 converts the PWM control signal V _p into a voltage signal, the comparator 145 generates a PWM signal V _PWM from the voltage signal and the triangular wave input to output to modulation section 146 to 151. Modulator 146-
The modulating unit 151 controls the six-phase control signals UH ₀ , UL ₀ , VH ₀ , VH
PWM-modulated six-phase control signals UH, UL, by taking the product logic of L ₀ , WH ₀ , WL ₀ and the PWM signal V _PWM
VH, VL, WH, WL are generated, and the commutator element 1 is generated.
Output to 05-110. Thereby, the stator winding 102
The currents flowing through u, 102v, and 102w are PWM-modulated, and the applied power is suppressed.

The control method of the drive control device for the brushless motor according to the present embodiment configured as described above will be described below.

When starting the brushless motor, three-phase control is performed.
The signal switching unit 134 is generated by the external synchronization control unit 131
External synchronous three-phase control signal V_Ai, V_Bi, V_CiThe three phase control signal
V_A, V_B, V_CAnd the brushless motor is
Driven in a synchronous control state. At this time, the current detector
136 is the total current value supplied to the drive circuit 104
Continue to detect. The rotation speed increases, and the permanent magnet rotor 103
The induced voltage due to the rotation of the
When it becomes large enough to output, the feedback three-phase control signal generator
132 is an induced voltage zero crossing point detection signal V_ZAnd
Detect signal V_sStart outputting. Edge detection signal V_sEnters
When the power is applied, the applied power suppression determination unit 137 immediately
Is the phase current value I detected by the current detection unit 136._fUOr
I_fVOr I_fWAnd threshold I₀And the phase current value I_fU
Or I_fVOr I_fWIs the threshold I₀If greater,
Control to suppress the applied power is permitted. At this time,
In the initial state, control to suppress applied power is not permitted.
You are in a state. Applied by the applied power suppression determination unit 137
When the control for suppressing the power is permitted, the applied power control unit
161 is detected by the current detector 136 immediately before the commutation point.
Detected phase current value I _fUOr I_fVOr I_fWBased on
To determine how much the applied power should be suppressed. And
In both cases, the PWM control is switched before commutation, and the stator is
Reduce the value of current flowing through windings 102u, 102v, 102w
Control.

When the rotation speed N of the permanent magnet rotor 103 detected by the rotation speed detection unit 133 exceeds a certain value, the three-phase control signal switching unit 134 sends an input to the feedback three-phase control signal generation unit 132. Switching, feedback three-phase control signal V _Af ,
V _Bf and V _Cf are output to the six-phase control signal generator 135 as three-phase control signals V _A , V _B and V _C to enter a feedback control state. At this time, the stator windings 102u, 102v, 1
Since the value of the current flowing through 02w is suppressed before commutation, it is possible to prevent a state in which the pulse width of the surge voltage is large and the zero-cross point is not detected as shown in FIG.

Next, the switching operation of the applied power by the control unit will be described in more detail. FIG. 7 is a flowchart showing the switching operation of the applied power by the control unit in FIG. 5, and FIG. 8 is a diagram showing the time change and timing of each signal in FIG. In FIG. 8, A is a zero crossing point of an induced voltage generated at terminals U, V, and W, and B is each stator winding 102u, 10u.
A commutation point at which currents of 2v and 102w are commutated, and C ′ is an applied power switching point at which the applied power is switched.

[0097] First, applying power restriction judgment unit 137 detects the commutation point from the edge detection signal V _s (S201).

When the commutation point is detected, if the PWM control is being performed, the PWM control is stopped (S202), and the applied power control unit 161 counts the count value t of the timer provided therein.
Is reset to 0, and the timer starts counting (S203).

Immediately before the commutation point, the applied power suppression determination unit 137 determines that the six-phase control signal UL is in the HIGH state (S2
04), the U-phase current value I _fU detected by the current detection unit 136 immediately before the commutation point, the threshold value I _0, and the threshold value I ₁ (I ₀ > I ₁ )
Are compared (S205). When the six-phase control signal VL is in the HIGH state immediately before the commutation point (S206),
Inversion V-phase current value detected by the current detecting section 136 immediately before the flow point I _fV values and the threshold I ₀ and the threshold _{I 1 (I 0> I 1} ) and comparing (S207). Also, if Rokusho control signal WL immediately before the commutation point is HIGH state (S206), the value and the threshold I ₀ and the detected W-phase current value I _fW by the current detecting section 136 immediately before the commutation point It is compared with a threshold value I ₁ (I ₀ > I ₁ ) (S208). Applying power restriction judging unit 137, the result of the comparison, if the phase current value I _fU or I _fV or I _fW is smaller than the threshold value I ₁ returns the control for suppressing the applied power to the step S201 disallowed , the phase current value I _fU or I _fV or I _fW is the case of more than the threshold value I ₀ permits the control for suppressing the applied power. I ₁ <I _fU , I _fV , I
_fW <when I ₀ maintains the current state of permission or refusal, in the case of prohibition process returns to step S201, in the case of authorization the flow advances to step S210 (S209).

When the control to suppress the applied power is permitted by the applied power suppression determining unit 137, the applied power control unit 1
61 is based on the phase current value I _fU or I _fV or I _fW ,
The amount of suppression of the applied power is determined. Determining therewith, to predict the time T from the commutation point to the next commutation point by the rotational speed N detected by the rotation speed detector 133, the time t ₁ to reduce the applied power from the commutation point ( For example, t ₁ = 0.8T
Decided like. However, 0.5T <t ₁ <T is satisfied (S2
10).

Next, the applied power control unit 161 waits until the count value t of the timer becomes t ₁ or more (S211).
When the count value t of the timer becomes t ₁ or more, the PWM
The control is switched to the PWM control by the control unit 162, and the applied power is suppressed (S212).

Thereafter, the flow returns to step S201, and the same operation is repeated. At this time, the waveforms of the signals of the respective parts in FIG. 5 are as shown in FIG.

The six-phase control signals UH, UL, which are the base voltages of the commutator elements 105 to 110,
VH, VL, WH, WL are switched to PWM control at the applied power switching point C ′, and the applied power is suppressed. Thereby, the power applied to the stator windings 102u, 102v, 102w decreases, the applied power at the commutation point B is suppressed, and the stator windings 102u, 102
v, the magnetic field energy in 102w decreases. Therefore,
The pulse width of the surge voltage generated when the commutator elements 105 to 110 are switched at the commutation point B is reduced, and the zero-cross point A of the terminal voltages V _U , V _V , V _W can be detected (FIG. 8 of _{V U,} V V, reference V _W).

At the commutation point B, the six-phase control signals UH, U
PWM control of L, VH, VL, WH, WL is terminated,
The original power value is again applied to the stator windings 102u, 102v, 102w.

At this time, the total current I flowing through the drive circuit 104 and the phase current detection signals V _{IU of} the U, V, and W phases,
V _IV and V _IW are as shown in FIG. The applied power suppression determination unit 137 detects the values of the phase current detection signals V _IU , V _IV , and V _IW at the point D immediately before the commutation point by the commutator element 106, and thereby detects the phase current immediately before the commutation point B. Value I
_fU, I _fV, to detect the I _fW.

In the present embodiment, the timing for suppressing the applied power is determined as the time when the timer is started with the rising of the surge voltage pulse (commutation point B) as a trigger and delayed by a certain time. , The timer may be started with the zero-cross point A as a trigger, and the time may be determined to be delayed by a certain time. Further, in the same manner as in the first embodiment, the applied power suppression determination unit 137 determines permission / non-permission of control for suppressing applied power by detecting the total current value I immediately before the commutation point B. May be configured.

Further, in the present embodiment, applied power suppression determination section 137 detects total current value _If immediately before commutation point B and permits / disables applied power suppression before the next commutation point. Although the permission is determined, the applied power suppression determination unit 137 determines
Current detector 136 during the edge detection signal V _s from the previous commutation points for each commutation point is detected until the commutation point
Average value _Iev or effective value I of all current values detected by
_eff may be calculated, and the value may be used to determine whether to permit or prohibit the suppression of the applied power before the next commutation point.
Further, in this case, the applied power control unit 161 is configured to determine the suppression amount of the applied power based on the average value I _ev or the effective value I _eff of all the current values calculated by the applied power suppression determination unit 137. Is also good. As a result, the influence of noise is reduced, malfunction is prevented, and the zero-cross point can be reliably detected.

(Embodiment 3) FIG. 9 is a block diagram showing a device configuration of a drive control device for a brushless motor according to Embodiment 3 of the present invention.

In FIG. 9, reference numeral 101 denotes a stator;
u, 102v, 102w are stator windings, 103 is a permanent magnet rotor, 104 is a drive circuit, 105 to 110 are commutator elements, 111 to 116 are freewheeling diodes, 117 is a drive power supply, 118 is a bypass capacitor, 120 Denotes a zero-crossing point detector, 120u, 12
0 v, 120 w comparator, R _I is the total current value detection resistor, UH, UL, VH, VL , WH, WL are six phase control _{signal, i u, i v, i} w is the driving current, V _N neutral potential , V _U ,
V _V, V _W is the terminal _{voltage, V U0, V V0, V} W0 is the zero-cross point detection signal, V _I is the total current detection signal, these are illustrated in Figures 1
Therefore, the same reference numerals are given and the description is omitted. Reference numerals 119U and 119L denote neutral potential generating resistors, which are the same as those shown in FIG.

171 is a current source for adjusting the power supply current;
₁ to Q _m is an NPN transistor for switching the current value of the driving power supply 117 current switching element,
D _{1 to} D _m are Zener diodes for obtaining a constant voltage on the cathode side, and R _{s1 to} R _sm are step-down resistors for obtaining the base voltage of the current source 171.

The current source 171 is constituted by a PNP transistor, the emitter is connected to the positive electrode of the current source 171, and the collector is connected to the emitters of the commutator elements 105 to 107 and the neutral potential generating resistor 119u. One end of the step-down resistors R _{s1 to} R _sm is connected to the base of the current source 171, and the other ends of the step-down resistors R _{s1 to} R _sm are connected to the cathodes of Zener diodes D _{1 to} D _m , respectively. I have. The anode side of the Zener diode D ₁ to D _m is connected to the collector of the current switching element Q ₁ to Q _m, respectively, the control unit 121 emitter side of the current switching element Q ₁ to Q _m through the resistor It is connected. The step-down resistors R _si (i = 1, 2,..., M) are set so that their resistance values decrease in ascending order of the index i.

FIG. 10 is a block diagram showing the functional configuration of the control unit shown in FIG. In FIG. 10, reference numeral 121 denotes a control unit,
31 is an external synchronization control unit, 132 is a feedback three-phase control signal generation unit, 133 is a rotation speed detection unit, 134 is a three-phase control signal switching unit, 135 is a six-phase control signal generation unit, 136 is a current detection unit, and 137 is V _U0 , V _V0 , V _W0 are zero-cross point detection signals, V _Ai , V _Bi , and V _Ci are external synchronous three-phase control signals, and V _Af , V _Bf , and V _Cf are feedback three-phase control signals. , V
_A, V _B, V _C is the three-phase control signal, V _I is the total current detection signal, U
H, UL, VH, VL, WH, WL are six-phase control signals, V
_Z is induced voltage zero-cross point detection signal, V _s is the edge detection signal, these are the same as FIG. 2, its description is omitted with the same reference numerals.

When the applied power suppression determining unit 137 determines that the applied power is to be suppressed, the current source 171 is turned on.
The power supply current control unit controls the switching of the base voltage.

[0114] applying power restriction judging unit 137, the rise of the surge pulse of induced voltage from the edge detection signal V _s (hereinafter, referred to as a commutation point.) Is detected, is detected by the current detecting section 136 immediately before The current value _If is compared with the threshold value I ₀ and the threshold value I ₁ (I ₀ > I ₁ ), and the current value _If is set to the threshold value I ₁
Is smaller than is the control for suppressing the applied power disallowed, the current value I _f is the case of more than the threshold value I ₀ permits the control for suppressing the applied power. Power supply current controller 181
When the control to suppress the applied power is permitted by the applied power suppression determination unit 137, the current source 1 is calculated based on the current value _If immediately before the commutation point detected by the current detection unit 136.
The amount of suppression of the base voltage at 71 is determined,
The rotational speed N detected by the 3 predicts the time from the commutation point to the next commutation point, the current by switching the base voltage switching signal P ₁ to P _m before a certain time of the next commutation point The base voltage of the source 171 is suppressed. When the base voltage of the current source 171 switches, the amount of current supplied to the drive circuit 104 decreases, and as a result, the stator windings 102u,
The amount of current flowing through 02v and 102w also decreases, and the applied power is suppressed.

The control method of the drive control device for the brushless motor of the present embodiment configured as described above will be described below.

When the brushless motor is started, the three-phase control signal switching unit 134 converts the external synchronization three-phase control signals V _Ai , V _Bi , and V _Ci generated by the external synchronization control unit 131 into three-phase control signals V _A , V _B. is output as V _C, the brushless motor is driven by an external synchronous control state. At this time, the current detection unit 136 continues to detect the total current value supplied to the drive circuit 104. The rotation speed increases, and the permanent magnet rotor 103
If voltage induced by the rotation of the increases enough to be detected by the zero-cross point detecting unit 120, a feedback three phase control signal generation unit 132 starts to output an induced voltage zero cross point detection signal V _Z and edge detection signal V _s. When the edge detection signal V _s is inputted, applied power restriction judging section 137 compares the current value I _f and the threshold I ₀ detected by the current detecting section 136 immediately before the commutation points, the current value I _f When it is larger than the threshold value I _0, control for suppressing the applied voltage is permitted. At this time, in the initial state, it is assumed that the control for suppressing the applied voltage is in a non-permitted state. When the control to suppress the applied voltage is permitted by the applied power suppression determination unit 137, the power supply current control unit 181 detects the current value _If and the rotation speed detected by the current detection unit 136 immediately before the commutation point. based on the rotational speed N detected by the section 133 determines the start time starts to suppress the applied power before commutation, constant base voltage switching signal P ₁ to P _m from P ₁ in order of decreasing indexes before commutation By switching every time Δt, the base voltage of the current source 171 is reduced every fixed time Δt, and the stator winding 102
Control is performed to suppress the current value flowing through u, 102v, and 102w.

When the rotation speed N of the permanent magnet rotor 103 detected by the rotation speed detection unit 133 exceeds a predetermined value, the three-phase control signal switching unit 134 inputs the input to the feedback three-phase control signal generation unit 132. Switching, feedback three-phase control signal V _Af ,
V _Bf and V _Cf are output to the six-phase control signal generator 135 as three-phase control signals V _A , V _B and V _C to enter a feedback control state. At this time, the stator windings 102u, 102v, 1
Since the value of the current flowing through 02w is suppressed before commutation, it is possible to prevent the pulse width of the surge voltage from being wide as shown in FIG. 16 so that the zero cross point is not detected.

Next, the switching operation of the applied power by the control unit will be described in more detail. FIG. 11 is a flowchart showing the switching operation of the applied power by the control unit in FIG.
FIG. 12 is a diagram showing the time change and timing of each signal in FIG. In FIG. 12, A is a zero crossing point of an induced voltage generated at terminals U, V, and W, and B is each stator winding 102.
commutation point for commutating the current of u, 102v, 102w, C
Is a base voltage switching point where the base voltage of the current source 171 is switched.

[0119] First, applying power restriction judgment unit 137 detects the commutation point from the edge detection signal V _s (S301).

When the commutation point is detected, the power supply current control unit 1
Timer 81 having a P ₁ HIGH state, is set to steady-state value of the base voltage of the current source 171 and the P ₂ to P _m and LOW state (the value when not suppressed supply current) (S302), the interior Is reset to 0, and the timer starts counting (S303).

[0121] Then, the applied power restriction judging unit 137, the rolling current value detected by the current detecting section 136 immediately before the flow point I _f values and the threshold I ₀ and the threshold _{I 1 (I 0> I 1} ) Are compared (S304). At this time, the applied power suppression determination unit 13
7, when the current value I _f is smaller than the threshold value I ₁ returns the control for suppressing the applied power to the step S301 disallowed, if the current value I _f is not less than the threshold value I ₀ is applied power Control to suppress the above is permitted. When I ₁ <I _f <I ₀ , the current permission or non-permission state is maintained, and the process returns to step S301 (S305).

When the control to suppress the applied power is permitted by the applied power suppression determination unit 137, the power supply current control unit 1
81 determines a base voltage of the current source 171 immediately before the next commutation point from the current value _If , and determines a switching interval Δt when switching the base voltage switching signals P _{1 to} P _m before commutation. I do. At the same time, the time T from the commutation point to the next commutation point is predicted from the rotation speed N detected by the rotation speed detection unit 133, and the time t from the commutation point to the suppression of the base voltage of the current source 171 determine _one (e.g., determined as t ₁ = 0.8 T. However, 0.5T <t ₁ <T) to (S30
6).

Next, the power supply current control unit 181 waits until the count value t of the timer becomes t ₁ or more (S307),
When the count value t of the timer becomes t ₁ or more, HI
The GH state is changed from P ₁ to the index in descending order (P ₁ , P ₂ ,
(In the order of P ₃ ,...) At the time intervals of Δt, thereby starting the suppression of the base voltage of the current source 171, and suppressing the applied power by suppressing the power supply current (S 308).

Thereafter, the flow returns to step S301 to repeat the same operation. At this time, the waveforms of the signals of the respective parts in FIG. 9 are as shown in FIG.

The voltage V ₀ 'with respect to the ground potential on the emitter side of the commutator elements 105-107.
Starts dropping at the base voltage switching point C and drops stepwise to the commutation point B at intervals of Δt. As a result, the total current value I starts to decrease before the commutation point, and the stator winding 102
The current flowing in u, 102v, 102w decreases, and the magnetic field energy in the stator windings 102u, 102v, 102w at the commutation point decreases. Therefore, the pulse width of the surge voltage generated when the commutator elements 105 to 110 are switched at the commutation point B decreases, and the terminal voltage V
_U, it is possible to detect _V V, the zero cross point of the V _W A (see _{V U,} V V, V _W in FIG. 12).

[0126] In the commutation point B, the base voltage switching signal is switched to P _1, the power supply current is again returned to the original current.

[0127] At this time, the total current detection signal V _I, which is the voltage generated at both ends of the total current value detection resistor R _I is 12
It becomes as shown in. Applying power restriction determination unit 137, by detecting the value of the total current detection signal V _I at point D immediately before the commutation points by commutator element 106, detects a total current value I _f immediately before the commutation point B .

In the present embodiment, the timing for suppressing the base voltage is determined as the time when the rising of the surge voltage pulse (commutation point B) is used as a trigger to start the timer and delay by a certain time. Alternatively, the time may be determined as the time when the timer is started with the falling of the surge voltage pulse (point E in FIG. 12) or the zero-cross point A as a trigger and delayed by a certain time.

Further, in the present embodiment, applied power suppression determination section 137 detects total current value _If immediately before commutation point B and permits / disables applied power suppression before the next commutation point. Although the permission is determined, the applied power suppression determination unit 137 determines
Current detector 136 during the edge detection signal V _s from the previous commutation points for each commutation point is detected until the commutation point
Average value _Iev or effective value I of all current values detected by
_eff may be calculated, and the value may be used to determine whether to permit or prohibit the suppression of the applied power before the next commutation point.
Further, in this case, the power supply current control unit 181 is configured to determine the suppression amount of the applied power based on the average value I _ev or the effective value I _eff of all the current values calculated by the applied power suppression determination unit 137. Is also good. As a result, the influence of noise is reduced, malfunction is prevented, and the zero-cross point can be reliably detected.

Further, in the present embodiment, when the base voltage of the current source 171 is lowered before the commutation point, the base voltage is sequentially lowered at regular time intervals Δt. May be lowered by a waveform approximating a sine wave. FIG. 13A is a diagram illustrating a time change of a voltage induced in each phase due to a change in magnetic flux, and FIG. 13B is a diagram illustrating a time change of the voltage V ₀ ′. As shown in FIG.
The voltage induced in each of the U-phase, V-phase, and W-phase due to the change of the magnetic flux inside becomes a sinusoidal wave (the voltage actually generated at terminals U, V, and W A voltage generated by the supplied current and a surge voltage overlap each other). Therefore, the power supply current control unit 181
FIG. 1 shows the drop of the total current value I after the base voltage switching point C.
In the section T _{U of} FIG. 3 (b), the voltage is lowered by a waveform approximating a sine wave in accordance with the shape of the induced voltage of the U phase, and the section T _V
Is decreased by a waveform approximating a sine wave that matches the shape of the V-phase induced voltage, and in section TW, it is decreased by a waveform approximating a sine wave that matches the shape of the W-phase induced voltage. Thereby, the stator windings 102u, 102
The currents flowing through v and 102w correspond to changes in the magnetic flux density created by the permanent magnet rotor 103, and control can be performed to suppress the applied power immediately before the commutation point while suppressing the reduction in the efficiency of the brushless motor.

[0131]

As described above, according to the drive control apparatus for a brushless motor of the present invention, the following effects can be obtained.

According to the first aspect of the present invention, the applied power control section suppresses the power applied to the stator winding from a fixed time before the switching point to the switching point, so that the applied power is fixed at the switching point. The energy of the magnetic field stored in the slave winding is suppressed. Therefore, the pulse width of the surge voltage can be reduced, so even if the current flowing through the stator winding is large, such as a high-output, high-speed brushless motor, the zero-cross point detection unit detects the induced voltage zero-cross point. This makes it possible to provide a brushless motor drive control device capable of performing sensorless control of phase switching of the commutator element by feeding back the rotational position of the permanent magnet rotor. Further, since the pulse width of the surge voltage is narrow, it is possible to provide a drive control device for a brushless motor in which electromagnetic noise during phase switching is reduced.

According to the second aspect of the present invention, the applied power control unit controls the amount of power applied to each stator winding based on the total current value, the phase current value, or the average value or the effective value thereof. By optimizing, it is possible to provide a brushless motor drive control device with high power efficiency.

According to the third aspect of the present invention, when the applied power suppression determining unit determines that the total current value or the phase current value detected by the current detecting unit or their average value or effective value is larger than a certain value. Only the power applied to the stator windings is suppressed, so that it is possible to provide a brushless motor drive control device with high power efficiency when operating at low output and low rotation.

According to the fourth aspect of the present invention, the applied power control section suppresses the base voltage applied to each commutator element a fixed time before the switching point, so that the stator winding is fixed before the switching point. And a drive control device for the brushless motor in which the drive current supplied to the motor is suppressed. Further, since the suppression of the drive current is not the suppression by the ON / OFF control, it is possible to provide a drive control device for a brushless motor having low electric noise at the time of suppression.

According to the fifth aspect of the present invention, the applied power control section performs pulse width modulation of the base voltage of each commutator element or the voltage applied to the drive circuit a predetermined time before the switching point, thereby providing a stator winding. It is possible to provide a drive control device for a brushless motor in which the power applied to the motor is suppressed. Further, it is possible to provide a brushless motor drive control device which has a small commutator loss, has a simple configuration, and can smoothly control the amount of applied power suppression due to pulse width modulation.

According to the sixth aspect of the present invention, the applied power control section suppresses the voltage applied to the drive circuit by the voltage source or the current applied to the drive circuit by the current source a fixed time before the switching point, thereby fixing the applied voltage. It is possible to provide a brushless motor drive control device capable of suppressing the drive current supplied to the slave winding.

According to the seventh aspect of the present invention, the applied power control unit sets the voltage source to a predetermined time before the switching point in response to the change in the magnetic flux density formed inside the stator winding by the permanent magnet rotor. Since the voltage or current source applied to the drive circuit suppresses the current applied to the drive circuit, a reduction in the power efficiency of the brushless motor is suppressed, and the drive control of the brushless motor in which the drive current supplied to the stator winding is suppressed. An apparatus can be provided. Further, it is possible to provide a drive control device for a brushless motor capable of detecting a zero-cross point without generating a surge voltage and preventing generation of electromagnetic noise caused by the surge voltage.

According to the brushless motor drive control method of the present invention, the following effects can be obtained.

According to the eighth aspect of the present invention, the power applied to the stator winding is suppressed from a predetermined time before the switching point to the switching point, so that the electric power stored in the stator winding at the switching point is suppressed. The energy of the magnetic field is suppressed. Therefore, the pulse width of the surge voltage can be reduced, so even if the current flowing through the stator winding is large, such as a high-output, high-speed brushless motor, the zero-cross point detection unit detects the induced voltage zero-cross point. This makes it possible to provide a brushless motor drive control method capable of performing sensorless control by feeding back the rotational position of the permanent magnet rotor in phase switching of the current flowing through the stator winding.

According to the ninth aspect of the present invention, the amount of suppression of the electric power applied to each stator winding is optimized based on the total current value, the phase current value, or the average value or the effective value thereof. A drive control method for a brushless motor with high power efficiency can be provided.

According to the tenth aspect of the present invention, when the applied power suppression determining unit determines that the total current value or the phase current value detected by the current detecting unit or their average value or effective value is larger than a certain value. Only the power applied to the stator windings is suppressed, so that it is possible to provide a drive control method for a brushless motor with high power efficiency when operating at low output and low rotation.

According to the eleventh aspect, the electric power applied to the stator winding a predetermined time before the switching point corresponding to the change in the magnetic flux density created inside the stator winding by the permanent magnet rotor. Therefore, it is possible to provide a brushless motor drive control method in which a decrease in power efficiency of the brushless motor is suppressed and a drive current supplied to the stator winding is suppressed. Further, it is possible to provide a drive control method for a brushless motor that can detect a zero-cross point without generating a surge voltage and can prevent the generation of electromagnetic noise caused by the surge voltage.

According to the twelfth aspect of the present invention, the power applied to the stator windings is modulated by pulse width modulation of the base voltage of each commutator element or the voltage applied to the drive circuit a predetermined time before the switching point. Thus, it is possible to provide a brushless motor drive control method in which the occurrence of the electric current is suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a device configuration of a drive control device for a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a functional configuration of a control unit in FIG. 1;

FIG. 3 is a flowchart showing a base voltage switching operation of a control unit in FIG. 1;

FIG. 4 is a diagram showing time change and timing of each signal in FIG. 1;

FIG. 5 is a block diagram showing a device configuration of a drive control device for a brushless motor according to a second embodiment of the present invention;

FIG. 6 is a block diagram illustrating a functional configuration of a control unit in FIG. 5;

FIG. 7 is a flowchart showing the switching operation of the applied power by the control unit in FIG. 5;

FIG. 8 is a diagram showing time change and timing of each signal in FIG. 5;

FIG. 9 is a block diagram showing a device configuration of a drive control device for a brushless motor according to a third embodiment of the present invention.

FIG. 10 is a block diagram illustrating a functional configuration of a control unit in FIG. 9;

11 is a flowchart showing the switching operation of the applied power by the control unit in FIG. 9;

FIG. 12 is a diagram showing time change and timing of each signal in FIG. 9;

13A is a diagram showing a time change of a voltage induced in each phase due to a change of a magnetic flux. FIG. 13B is a diagram showing a time change of a voltage V ₀ ′.

FIG. 14 is a block diagram showing a device configuration of a conventional brushless motor drive control device.

FIG. 15 is a diagram showing a time change of a terminal voltage of each stator winding in FIG. 14;

FIG. 16 is a diagram showing a change over time of the terminal voltage of each stator winding in FIG. 14 when the drive current is large.

[Explanation of symbols]

101 stator 102u, 102v, 102w stator winding 103 permanent magnet rotor 104 drive circuit 105, 106, 107, 108, 109, 110 commutator elements 105a, 106a, 107a, 108a, 109a,
110a switching circuit 111, 112, 113, 114, 115, 116 freewheeling diode 117 drive power supply 118 bypass capacitor 119u, 119v, 119w, 119U, 119L,
119N Neutral potential generation resistor 120 Zero cross point detection unit 120u, 120v, 120w Comparator 121 Control unit 131 External synchronization control unit 132 Feedback three-phase control signal generation unit 133 Rotation speed detection unit 134 Three-phase control signal switching unit 135 Six-phase control signal Generation unit 136 Current detection unit 137 Applied power suppression determination unit 138 Base voltage control unit 139 Base voltage switching unit 141 Pulse width modulation unit 142 F / V converter 143 Oscillator 144 Integration circuit 145 Comparator 146, 147, 148, 149, 150, 151 Modulation section 161 Applied power control section 162 PWM control section 171 Current source 181 Power supply current control section i _u , i _v , i _w drive current V _N Neutral potential V _U , V _V , V _W terminal voltages V _U0 , V _V0 , V _W0 zero-crossing point detection signal V _Ai, V _Bi, V _Ci external synchronizing the three-phase system Signal V _Af, V _Bf, V _Cf feedback three-phase control signals V _A, V _B, V _C three-phase control signals V _I total current detection signal V _IU, V _IV, V _IW-phase current detection signals UH, UL, VH, VL, WH, WL, UH ₀ , UL ₀ ,
_{VH 0, VL 0, WH 0} , WL 0 six phase control signal V _Z induced voltage zero cross point detection signal V _s edge detection signal V _b1, V _b2, V _bn base voltage switching signal V _p PWM control signal V _PWM PWM signal S _Q applied power switching signal R _I total current value detection resistor R _IU, R _IV, R _IW phase current detection resistor _{R UH1, R UH2, R UHn} , R VH1, R VH2, R VHn, R WH1,
R _WH2 , R _WHn , R _UL1 , R _UL2 , R _ULn , R _VL1 , R _VL2 ,
R _VLn , R _WL1 , R _WL2 , R _WLn Base voltage setting resistors R _s1 , R _s2 , R _sm Step-down resistors Q ₁ , Q ₂ , Q _m Current switching elements D ₁ , D ₂ , D _m Zener diodes P ₁ , P _2, P _m base voltage switching signal

Claims (12)

[Claims] 1. A brushless motor drive control device comprising: a plurality of stator windings connected at one point; and a permanent magnet rotor that is rotationally driven by a magnetic field generated by each of the stator windings. A drive circuit having a plurality of commutator elements for switching a current supplied to the stator winding by switching the commutator elements, and detecting a zero-cross point from a terminal voltage of each stator winding to perform the fixed operation. A zero-crossing point detection unit that outputs a zero-crossing point detection signal corresponding to each of the slave windings, and a section in which an induced voltage induced in the stator winding by rotation of the permanent magnet rotor is detected as the terminal voltage. An induced voltage zero-cross point, which is a zero-cross point, is extracted from each of the zero-cross point detection signals, and is delayed by a certain electrical angle from the induced voltage zero-cross point, so that each of the commu A feedback control signal generation unit that performs control to switch the phase of the commutator element, and suppresses electric power applied to the stator winding from a predetermined time before the switching point at which the commutator element is switched to the switching point. A drive control device for a brushless motor, comprising: an applied power control unit for performing control. A current detection unit for detecting a total current value or a phase current value supplied to the stator winding, wherein the applied power control unit detects the total current value or the phase current value detected by the current detection unit. 2. The drive control device for a brushless motor according to claim 1, wherein a suppression amount of power applied to each of the stator windings is determined based on the phase current values or an average value or an effective value thereof. 3. 3. A current detecting section for detecting a total current value or a phase current value supplied to the stator winding, and the total current value or the phase current value detected by the current detecting section or an average thereof. An applied power suppression determination unit that performs a determination that permits suppression of the applied power to each of the stator windings when the value or the effective value is greater than a certain fixed value. 2. The brushless motor according to claim 1, wherein when the suppression of the applied power is permitted by the suppression determination unit, control is performed to suppress the power applied to each stator winding a predetermined time before the switching point. 3. Drive control device. 4. The apparatus according to claim 1, wherein the applied power control unit performs control for suppressing a base voltage applied to each of the commutator elements a predetermined time before the switching point. A drive control device for a brushless motor according to any one of the preceding claims. 5. A pulse width modulation section for pulse width modulating a base voltage of each of the commutator elements or a voltage applied to the drive circuit, wherein the applied power control section performs a predetermined time before the switching point for each of the commutator elements. 4. The drive control device for a brushless motor according to claim 1, wherein the pulse width modulation unit performs pulse width modulation on a base voltage applied to the drive circuit or a voltage applied to the drive circuit. 5. 6. A variable output voltage source for supplying a voltage to be applied to the drive circuit or a variable output current source for supplying a current to be applied to the drive circuit. 4. The brushless motor according to claim 1, wherein the brushless motor according to claim 1, wherein the voltage source applies control to suppress a voltage applied to the drive circuit or a current applied to the drive circuit by the current source. 5. Drive control device. 7. The applied power control section performs control to lower the voltage applied to the drive circuit or the current applied to the drive circuit by a voltage approximating a sine wave by the voltage source a predetermined time before the switching point. The drive control device for a brushless motor according to claim 6, wherein: 8. A drive control method for a brushless motor comprising: a plurality of stator windings connected at one point; and a permanent magnet rotor that is rotationally driven by a magnetic field generated by each of the stator windings. A zero-crossing point detection step of detecting a zero-crossing point of each terminal voltage from a plurality of terminal voltages of the stator windings; and an induced voltage induced in the stator windings by rotation of the permanent magnet rotor. A magnetic pole position detecting step of extracting an induced voltage zero-cross point, which is a zero-cross point in a section detected as a voltage, from the zero-cross point detection signal of each terminal voltage; A current switching process of performing phase switching of a current flowing through the winding; and a current switching process for switching the current flowing through the stator winding from a predetermined time before the switching point to the switching point. And suppressing applied power suppression process the power to be applied to the stator windings, a drive control method for a brushless motor comprising the. 9. A current detection step for detecting a total current value or a phase current value supplied to said stator winding, and in said applied power suppressing step, a suppression amount of electric power applied to each of said stator windings. The drive control method for a brushless motor according to claim 8, wherein the determination is made based on the total current value or the phase current value detected in the current detection step, or an average value or an effective value thereof. 10. A current detecting step for detecting a total current value or a phase current value supplied to said stator winding, and said total current value or said phase current value detected in said current detecting step or an average thereof. An applied power suppression determining step of making a determination that permits suppression of the applied power to each of the stator windings when the value or the effective value is larger than a certain fixed value. When suppression of the power applied to each stator winding is permitted in the suppression determination process, the power applied to each stator winding is suppressed from a predetermined time before the switching point to the switching point. The drive control method for a brushless motor according to claim 8, wherein: 11. The method according to claim 8, wherein in the applied power suppressing step, the power applied to the stator winding is reduced by a waveform approximating a sine wave a predetermined time before the switching point. A drive control method for a brushless motor according to any one of the preceding claims. 12. The method according to claim 8, wherein in the applied power suppressing step, a voltage applied to each of the stator windings is pulse width modulated a predetermined time before the switching point. A drive control method for a brushless motor according to claim 1.