JP2000245190A - Apparatus and method for controlling driving of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain proper commutation timing and prevent step out, even if the number of revolutions varies due to variation in load by estimating at a control part a time interval, until the next zero cross point from the time interval of the zero cross point of the induced voltage induced in stator windings among the zero cross points detected in the past. SOLUTION: The zero cross point of an induced voltage, where the induced voltage induced in the stator windings 102u, 102v, and 102w due to the rotation of a permanent magnet rotor crosses a reference voltage, is detected at a zero cross point detection part 120. The time interval of the zero cross point of each induced voltage is detected, and the time interval until the zero cross point of the next induced voltage detected is estimated from the zero cross point of the last induced voltage detected in the past. The delay time, from the zero cross point of the last induced voltage detected in the past to phase shift, is determined from the estimated time interval at an phase shift amount calculating part 204. The phase of drive current is shifted using the determined delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a brushless motor which performs sensorless driving by detecting a magnetic pole position of a rotor by detecting a zero cross of an induced voltage induced in a stator winding, The present invention relates to a brushless motor drive control device and a drive control method that can be driven even when the number of changes is large.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Sho 59-123490 (hereinafter referred to as "A") discloses a method for coping with a change in the number of revolutions of a conventional sensorless drive. The signals are combined in a predetermined relationship, the combined voltage is compared with the reference voltage, and a switching signal for sequentially energizing each phase is obtained based on the comparison result. A brushless motor drive circuit characterized in that the maximum voltage among the induced voltages is used as the reference voltage, and in a region where the induced voltage is sufficiently large, the common power supply voltage of each phase is used as the reference voltage. Have been. In the drive circuit of the brushless motor disclosed in the above publication, the maximum induced voltage of each phase is used as the reference voltage when the brushless motor is started, and the power supply voltage is used as the reference voltage after the start.

[0003] Also, Japanese Patent No. 2642357 (hereinafter, referred to as "patent")
This is referred to as the “B” publication. ) Includes a reference voltage and a terminal voltage of each phase stator coil in a brushless motor including a permanent magnet rotor and a stator having a plurality of phases of stator coils for applying a magnetic field to apply a rotational force to the rotor. A comparator that outputs a signal indicating the positive, negative, and phase of the induced voltage generated in the stator coil of each phase according to the rotation of the rotor,
A first timer for measuring the change time of the induced voltage based on the output signal of the comparator, a second timer for obtaining a delay time based on the change time measured by the first timer, and an output signal of the comparator Logic operation means for outputting a drive signal for energizing the stator coils of the respective phases from the positive and negative states of the induced voltage based on the timing of the second timer and the logic operation means based on the drive signal from the logic operation means. Drive control device for brushless motor including output means for energizing stator coils of each phase "
Is disclosed. In the drive control device for a brushless motor disclosed in the above publication, the energization timing is determined based on the change time of the induced voltage. As a result, even if the rotational speed changes,
It is driven at a regular commutation timing, and no step-out occurs.

[0004] Hereinafter, a drive control apparatus for a brushless motor disclosed in Japanese Patent Application Laid-Open Publication No. H8-213, will be described in the prior art.

FIG. 11 is a diagram showing a method for determining the commutation timing from the zero cross point of the induced voltage in the drive control device for a brushless motor disclosed in Japanese Patent Publication No.

In FIG. 11, V _u is a U-phase terminal voltage waveform, V _v is a V-phase terminal voltage waveform, V _w is a W-phase terminal voltage waveform,
V _N is the neutral potential, which is the voltage at the neutral point of each phase terminal voltage, A
Are induced in the windings of each phase, and the terminal voltages V _U , V _V ,
The zero-cross point T of the induced voltage at which the induced voltage detected as V _W crosses the neutral potential V _N has a magnitude of 60 electrical degrees in time between the zero-cross points. B is a point (hereinafter, referred to as a commutation point) that is temporally delayed by half the time (30 electrical degrees) between the zero-cross point of the induced voltage and the zero-cross point of the induced voltage immediately before that. , Which is used as commutation timing. S is provided for releasing a surge voltage generated in the stator coil when the direction of the current flowing in the stator coil is switched at the commutation point B, and the surge voltage is generated. This is a surge pulse generated when an avalanche current flows through a constant voltage diode (freewheeling diode). In this method, the commutation timing is determined by using an electrical angle of 30 degrees, which is half of the electrical angle of 60 degrees from the zero cross point of the induced voltage, as the reference, to determine the commutation timing. Even in this case, the phase shift amount becomes certain, and a normal commutation timing can be obtained.

[0007]

However, even in a conventional brushless motor drive control device capable of obtaining a normal commutation timing even when the rotational speed changes as disclosed in the above-mentioned publication, There has been a problem that the motor may not be able to cope with a sudden change in the number of revolutions, such as before and after the end of the self-priming operation of the pump, and may lose synchronism.

If commutation is not performed at an appropriate timing, the current flowing through the brushless motor increases and the electric components are likely to be destroyed. Therefore, it is necessary to prevent the destruction by increasing the capacity of the electric components. The cost is high.

A drive control device for a brushless motor according to the present invention solves the above-mentioned conventional problems, and can obtain an appropriate commutation timing even when a sudden change in the number of revolutions occurs due to a change in load. An object of the present invention is to provide a brushless motor drive control device that does not lose synchronism.

Further, a drive control method for a brushless motor according to the present invention solves the above-mentioned conventional problem. It is possible to obtain an appropriate commutation timing even when a sudden change in rotation speed occurs due to a change in load. An object of the present invention is to provide a drive control method for a brushless motor that can be performed and does not lose synchronism.

[0011]

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 brushless motor drive control device for controlling a brushless motor having a rotating permanent magnet rotor, comprising a plurality of commutator elements, and energizing a stator winding by phase switching of each commutator element. A drive circuit for switching the drive current, and a zero-cross point detection unit for detecting a zero-cross point at which the terminal voltage of each stator winding crosses the reference voltage and outputting a zero-cross point detection signal corresponding to each of the stator windings. A control unit that controls the phase switching of the drive current of the drive circuit based on the zero-cross point detection signal. Zero-crossing point time interval estimating means for estimating a time interval from the zero-crossing point of the induced voltage induced in the stator winding to the zero-crossing point of the next induced voltage among the detected zero-crossing points; A delay time is determined from a zero-cross point of an induced voltage detected last in the past to a point at which a phase switching of a drive current is performed based on an estimated value of a time interval to a zero-cross point of the next induced voltage estimated by the estimating means. It comprises a phase shift amount determining means and a phase switching means for switching the phase of the drive current with a delay from the zero cross point of the induced voltage detected last in the past by a delay time.

With this configuration, it is possible to obtain a proper commutation timing even when a rapid change in the rotational speed occurs due to a change in load, and to provide a drive control device for a brushless motor that does not lose synchronism. it can.

According to another aspect of the present invention, there is provided a drive control method for a brushless motor, the method comprising: a plurality of stator windings connected at one point; and a magnetic field generated by each stator winding. A permanent magnet rotor, and a drive control method for a brushless motor that is energized and driven by performing phase switching synchronized with rotation to each stator winding of a brushless motor having the same, wherein the rotation of the permanent magnet rotor The induced voltage induced in each stator winding detects the zero-cross point of the induced voltage crossing the reference voltage, the time interval between the zero-cross points of each induced voltage is detected, and the induced voltage of the last detected voltage in the past is detected. The time interval from the zero-crossing point to the next zero-crossing point of the induced voltage is estimated from the time interval of the zero-crossing point of the previously detected induced voltage. Based on the time interval to the cross point, determine the delay time from the last cross-point of the induced voltage detected in the past to the phase switching, and delay by the delay time from the zero cross point of the last-detected induced voltage in the past And the drive current is switched in phase.

With this configuration, it is possible to obtain a proper commutation timing even when a sudden change in the rotational speed occurs due to a change in load, and to provide a drive control method for a brushless motor that does not lose synchronism. it can.

[0015]

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 brushless motor drive control device for controlling a brushless motor including a permanent magnet rotor that is driven to rotate by a generated magnetic field, the drive control device including a plurality of commutator elements, and a stator winding being performed by phase switching of each commutator element. A drive circuit that switches the drive current that flows through the wires, and a zero cross that detects a zero cross point where the terminal voltage of each stator winding crosses the reference voltage and outputs a zero cross point detection signal corresponding to each of the stator windings A point detection unit; and a control unit that controls phase switching of the drive current of the drive circuit based on the zero-cross point detection signal. A zero-crossing point time interval estimating means for estimating a time interval from the zero-crossing point of the induced voltage induced in the stator winding to the zero-crossing point of the next induced voltage among the zero-crossing points detected in the past; Delay time from the zero crossing point of the induced voltage detected last in the past to the point at which the drive current phase is switched based on the estimated value of the time interval up to the next induced voltage zero crossing point estimated by the point time interval estimating means , And phase switching means for switching the phase of the drive current by delaying by a delay time from the zero-cross point of the induced voltage detected last in the past. With this configuration, the following operation is obtained.

(1) An induced voltage is induced in the stator winding by the rotation of the permanent magnet rotor.
A zero cross point, which is a point where the reference voltage and the induced voltage cross, is detected.

(2) The zero-crossing point time interval estimating means:
Of the zero-cross points detected by the zero-cross point detection unit, the zero-cross point of the induced voltage is extracted, and the zero-cross point of the induced voltage of any of the extracted phases and the phase of the phase detected next are extracted. The time interval between any of the induced voltages and the zero-cross point is sequentially detected, and the time interval of the next detected zero-cross point is estimated from the sequence of the detected zero-cross point time intervals of the induced voltage.

(3) The phase shift amount determining means determines the drive current from the zero-cross point of the induced voltage detected last in the past from the time interval of the next detected zero-cross point estimated by the zero-cross point time interval estimating means. Calculate and determine the delay time up to the point where phase switching is performed.

(4) The phase switching means measures the elapsed time from the zero crossing point of the induced voltage detected last in the past,
When the elapsed time reaches the delay time determined by the phase shift amount determining means, phase switching of the drive current is performed.
Thereby, the drive current flowing through the stator winding is switched in synchronization with the rotation of the permanent magnet rotor.

(5) The zero-crossing point time interval estimating means:
Since the interval between the zero-cross points of the next induced voltage is estimated from the interval between the zero-cross points of the past induced voltage, the interval between the zero-cross points of the next induced voltage is accurately estimated even when the interval between the zero-cross points changes rapidly. be able to.

(6) Even if a sudden change in the number of revolutions occurs due to a change in the load applied to the rotating shaft of the brushless motor,
Appropriate commutation timing can be obtained, and loss of synchronism is prevented. Also, when the drive voltage is changed in order to change the performance of the brushless motor, a sharp change in the number of revolutions occurs. In particular, the acceleration component is large when the followability is required, but even in such a case, it is possible to obtain a proper commutation timing, and it is possible to prevent a loss of synchronism.

(7) In order to commutate at an appropriate timing,
High current resistance is not required for the electric components, and it is possible to configure the electric components with inexpensive components having low current resistance, which is excellent in economical efficiency.

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,
The zero-crossing point time interval estimating means uses the time interval of the zero-crossing point of the induced voltage detected in the past as a discrete function of time, and calculates the time interval until the next zero-crossing point of the induced voltage by using a differential value of the discrete function. This configuration is characterized by estimating, and the following operation is obtained by this configuration.

(1) Since the change in the number of revolutions is numerically captured by a function, it is possible to estimate the time interval until the next zero crossing point of the induced voltage.

(2) Since the time interval from the interval of the zero cross point detected in the past to the next zero cross point is estimated, even if the next zero cross point is not detected under the influence of noise, an appropriate It is possible to switch the phase of the drive current at the timing.

(3) By using the differential value of the series of the zero-crossing point time intervals, the acceleration component of the rotation speed can be accurately detected.

According to a third aspect of the present invention, there is provided the drive control apparatus for a brushless motor according to the first or second aspect, wherein k and r are constants of 0 or more, and i is an integer of 1 or more. , N is an arbitrary integer constant of 1 or more, the time at which the zero-cross point of the induced voltage was last detected in the past is t _0, and the zero-cross point of the induced voltage was finally detected before time t _{-i + 1} . The time is t _-i , the time interval of the past induced voltage zero-cross point is T _i = t _{-i + 1} -t _-i, and the estimated value of the time interval T ₀ to the next induced voltage zero-cross point is T _{0. (in f)} , the coefficient A _k (r) is a constant defined by (Equation 4) and (Equation 5), and the zero-crossing point time interval estimating means:
By performing the calculation of (Equation 6), an estimated value T _{0 (inf)} of the time interval T ₀ up to the next zero-cross point of the induced voltage is determined.

[0028]

(Equation 4)

[0029]

(Equation 5)

[0030]

(Equation 6)

With this configuration, the following operation is obtained.

(1) The time interval up to the next zero-cross point of the induced voltage can be estimated with an accuracy corresponding to the processing capacity of the control unit.

(2) The control unit uses the time interval of the zero-cross point up to the past n times and uses the expansion formula up to the n-th derivative of the series of the time interval of the zero-cross point to obtain the time interval to the next zero-cross point. , The optimal control can be performed by determining the value of n according to the load characteristics (the characteristics of the number of rotations with respect to the torque) of the brushless motor and the load target. That is, for example, when the change in the rotation speed with respect to the change in the torque is large, the rotation speed changes greatly due to a small change in the torque. Control can be performed. Conversely, when the change in the number of revolutions with respect to the change in the torque is small, by performing estimation using a low-order expansion formula, it becomes possible to perform optimal control with a responsive response to a load change.

According to a fourth aspect of the present invention, there is provided a drive control device for a brushless motor according to the third aspect,
A time interval T ₁ of the up zero-cross point of the estimated value T _{1 (inf)} actually detected following induced voltage time interval T ₁ of the up zero-cross point of the next of the induced voltage zero cross point interval estimating means estimated Error detection and storage means for detecting and storing the error ΔT _err = T ₁ −T _{1 (inf) of the above} , and the zero-cross point time interval estimating means for estimating the error ΔT _err previously detected and stored in the past by the error detection and storage means Estimated value correction means for correcting the estimated value of the time interval to the next induced voltage zero crossing point by adding to the calculated time interval T ₀ to the next induced voltage zero crossing point. ,
Based on the estimated value of the time interval to the next induced voltage zero-cross point corrected by the estimated value correcting means, the delay time from the last detected induced voltage zero-cross point in the past to the drive current phase switching is determined. With this configuration, the estimated value T _{1 (inf)} of the interval to the zero-cross point of the previous induced voltage is changed to the actual interval T ₁ to the zero-cross point of the previous induced voltage. And the error
Since the feedback to the estimation of the interval T _{0 to} the next induced voltage zero crossing point can be fed back, an effect of being able to cope with rapid repetition of acceleration / deceleration can be obtained.

According to a fifth aspect of the present invention, there is provided the drive control apparatus for a brushless motor according to any one of the first to fourth aspects, wherein the phase shift amount determining means includes a zero cross point of the estimated next induced voltage. The delay time is set to 1/2 or 3/2 of the interval until the delay time, and the following operation is obtained by this configuration.

(1) The time at which the phase shift amount of the induced voltage from the zero-cross point becomes 30 degrees or 90 degrees can be accurately estimated.

(2) Since the phase switching is performed at an appropriate timing, it is possible to prevent a step out of the motor or a sharp rise in the motor current even during acceleration / deceleration.

According to a sixth aspect of the present invention, there is provided a drive control method for a brushless motor, comprising: a plurality of stator windings connected at one point; and a permanent magnet rotating driven by a magnetic field generated by each stator winding. A brushless motor drive control method for energizing and driving each of the stator windings of a brushless motor having a stator winding by performing phase switching synchronized with rotation, wherein each of the fixed windings is fixed by rotation of a permanent magnet rotor. Detects the zero-cross point of the induced voltage at which the induced voltage crosses the reference voltage, detects the time interval between the zero-cross points of each induced voltage, and calculates the zero-cross point of the induced voltage last detected in the past. The time interval up to the zero crossing point of the next induced voltage is estimated from the time interval of the zero crossing point of the induced voltage detected in the past, and until the zero crossing point of the next estimated induced voltage. Based on the time interval, determine the delay time from the last detected zero-cross point of the induced voltage to the phase switching, and delay the drive voltage from the last detected zero-cross point of the induced voltage by the delay time. The above-described phase switching is performed, and the configuration has the following operation.

(1) If the rotation speed of the brushless motor changes rapidly due to a change in the load applied to the rotating shaft, the interval between the zero-cross points of the induced voltage changes over time. It is possible to estimate the time interval up to the zero crossing point of the induced voltage to be obtained, to obtain a proper commutation timing, and to prevent loss of synchronism.

(2) Since phase switching is performed at an appropriate timing, step-out of the motor and a sharp rise in the motor current can be prevented even during acceleration / deceleration.

According to a seventh aspect of the present invention, there is provided a drive control method for a brushless motor according to the sixth aspect, wherein
The time interval between the zero cross points of the induced voltages detected in the past is a discrete function of time, and the time interval to the next zero cross point of the induced voltage is estimated by using the differential value of the discrete function. According to this configuration, a change in the number of revolutions is numerically captured as a function, so that an operation of estimating a time interval up to the next zero-cross point of the induced voltage can be obtained.

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, 101 is a stator of a brushless motor, 102u, 102v, and 102w are three-phase connected stator windings for generating a driving magnetic field in the stator 101, and 103 is a stator winding 102u, 102v, 102
The permanent magnet rotor 104, which is rotationally driven by the magnetic field generated by w, has stator windings 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.

119U and 119L are stator windings 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 is a control unit for controlling the rotation speed of the permanent magnet rotor 103 by controlling the drive circuit 104, and 122 is an input unit for the user to input a signal for control instruction to the control unit 121. .

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 the 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 _N 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 _N. Comparator 120u, 120v, 120 w, the terminal voltage V _U of each phase input, _V V, compared with the V _W and the neutral potential V _N, the terminal voltage V _{U, V} V, V _W neutral potential V When it is larger than _{N, the} zero-crossing point detection signals V _U0 , V _V0 , V _{W0 respectively}
Are output in a HIGH state, and the terminal voltages V _U , V _V , V _W
Are smaller than the neutral potential V _{N, the} zero-crossing point detection signals V _U0 , V _V0 , and V _W0 are output in a LOW state. The control unit 121 includes commutator elements 105 to 110
, And six-phase control signals UH, UL, VH, VL, and W for controlling the drive circuit 104.
H and WL are generated 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 .

FIG. 2 is a functional block diagram of the control unit of FIG.

In FIG. 2, reference numeral 120 denotes a zero-cross point detection unit, 120u, 120v, and 120w denote comparators,
21 is a control unit, V _U , V _V , V _W are terminal voltages, V _N is a neutral potential, V _U0 , V _V0 , V _W0 are zero-cross point detection signals, UH,
UL, VH, VL, WH, WL are six-phase control signals,
These are the same as those in FIG. 1, and the same reference numerals are given and the description is omitted.

Reference numeral 201 denotes a data input from the zero-cross point detection unit 120.
U-phase, V-phase, and W-phase zero-cross point detection signals
Issue V_U0, V_V0, V_W0From surge pulse (freewheel
Surge current flows through the switching diodes 111-116.
The zero crossing point due to the voltage pulse generated by
To extract only the zero-cross point due to the induced electromotive force
The loss point extraction unit 202 is extracted by the zero cross point extraction unit 201.
Measures the time interval of the zero crossing point by the induced voltage
Zero-cross point interval measuring unit 202a is a zero-cross point
Induction of each of the U phase, V phase, and W phase detected by the extraction unit 201
Synthesize pulse composed of zero crossing points by electromotive voltage
And a waveform synthesizing logic section 202b for outputting and outputting.
Zero-cross due to induced voltage of three phases synthesized in 202a
First time measurement timer for measuring the interval of the point pulse, 203
Is the induced voltage measured by the zero-crossing point interval measuring unit 202
Zero to temporarily store the time interval of the zero crossing point due to
Cross point time interval memory unit, 204 is zero cross point time
Time of zero cross point stored in interval memory unit 203
Read the interval and based on those values, at the next zero crossing point
A phase shift amount determining operation unit for predicting and determining the interval, 204
a is stored in the zero-cross point time interval memory unit 203
Time interval T of zero cross point_k(K = 0, 1,...,
m) is read and according to (Equation 4) to (Equation 11) described later.
Zero cross point interval T_{0 (inf)}Zero-cross point interval to estimate
The estimator 204b is estimated by the zero-crossing point interval estimator
Zero-crossing point interval T_{0 (inf)}1/2 times (hereinafter, 3
Called 0 degree phase shift time. ) Or 3/2 times (hereinafter, 9
Called 0 degree phase shift time. ) Last detected in the past
Switching of drive current from zero crossing point by induced electromotive force
Shift that is determined and output as the delay time until
The quantity determination unit 205 is output by the waveform synthesis logic unit 202a.
Phase triggered by zero-cross point due to induced electromotive force
30 degree phase set by the shift amount determination calculation unit 204
Shift time T_{0 (inf)}/ 2 or 90 degree phase shift time 3T
_{0 (inf)}/ 2 is measured and the feedback
Second time to output commutation timing signal for block control
The time measurement timer 206 is the set forced synchronization cycle time T
_cFor forced synchronous control when the time is reached
A third time measurement timer that outputs a commutation timing signal of
Reference numeral 207 denotes a plurality of strengths set in the third time measurement timer 206.
Synchronization cycle time T_cIs remembered and one of them
One by setting the third time measurement timer 206
The timer of the commutation timing signal output of the three-hour measurement timer 206
The forced synchronization cycle control unit for controlling the
Time measurement timer 205 or third time measurement timer 206
6-phase control signal U based on the commutation timing signal
H₀, UL₀, VH ₀, VL₀, WH₀, WL₀Switching system
A commutation control unit 209 for controlling
The output six-phase control signal UH₀, UL₀, VH₀, VL₀,
WH₀, WL₀Is input to amplify the current and the six-phase control signal U
H, UL, VH, VL, WH, WL
Signal buffer unit, 210 has an internal timer
From the time measurement timer 205 or the third time measurement timer 206
Second time activated by input commutation timing signal
Commutation between measurement timer 205 and third time measurement timer 206
Timing difference ΔT of timing signal output_{twenty three}Measure
A phase difference measurement unit that outputs the value, 211 is a phase difference measurement unit
ΔT measured by 210_{twenty three}Is the threshold ΔT₀Whether below
And the threshold is ΔT₀In the following cases, the commutation control unit 208
Input the commutation timing signal of the third time measurement timer 20
Control to switch from 6 to the second time measurement timer 205
Control switching unit 212, the first time measurement timer 202b,
Second time measurement timer 205, third time measurement timer 20
6. The timer for counting the phase difference
This is an oscillation circuit that outputs a clock.

The zero-cross point extracting unit 201 determines whether the detected zero-cross point is a zero-cross point caused by the rise of the surge pulse, a zero-cross point caused by the fall of the surge pulse, or a zero-cross point caused by the induced voltage. Is stored. J
= 0 indicates a state in which a zero-cross point has not been detected, J = 1 indicates a state in which the rising of a surge pulse has been detected, J = 2 indicates a state in which a falling of a surge pulse has been detected, and J =
Reference numeral 3 denotes a state in which a zero-cross point due to the induced voltage is detected.

The forced synchronization cycle control unit 207 has, in a memory provided therein, an array of timing signal generation times T _co (I) (I) representing the generation time intervals of the commutation timing signals of the forced synchronization control at the time of startup. = 0, 1,... N−1) and an array number I indicating the current timing signal generation time.

The commutation control unit 208 stores a mode selection flag H in a memory provided therein. When H = 0, a commutation timing signal input from the third time measurement timer 206 is received. Switching of the six-phase control signals UH ₀ , UL ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ is performed according to the timing. When H = 1, the commutation timing signal input from the second time measurement timer 205 is received. ,
The six-phase control signals UH ₀ , UL ₀ , VH
₀ , VL ₀ , WH ₀ , and WL ₀ are controlled. Less than,
The state of H = 0 is called a forced synchronization mode, and the state of H = 1 is called a feedback control mode. Further, the commutation control unit 208 stores a commutation immediately after detection flag K and a phase number M in a memory. K = 1 represents immediately after commutation, and K = 0 represents not immediately after commutation. M (= 0, 1, 2, 3,
4, 5) represent the phase numbers of the six-phase switching signal.

The phase difference measuring section 210 stores a timer number flag P in a memory provided therein. P = 0
Indicates that the timer of the phase difference measurement unit 210 is the second time measurement timer 2
05 indicates that the timer of the phase difference measurement unit 210 has been started by the third time measurement timer 206, and P = 2 indicates that the timer of the phase difference measurement unit 210 has been stopped. Indicates that there is.

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

First, the operation from the start of the brushless motor to the transition to the feedback control state will be described.

FIG. 3 is a flowchart showing an operation at the time of startup of the drive control method of the brushless motor drive control device according to the first embodiment. FIG. 4 is a flowchart showing the drive control method of the brushless motor drive control device of the first embodiment. FIG. 5 is a flowchart showing an operation at the time of switching from forced synchronous control to feedback control of FIG. 5, and FIG. 5 is a flowchart showing an operation at the time of feedback control of the drive control method of the drive control device for the brushless motor according to the first embodiment. 6 is a flowchart showing a control operation of interrupt processing 1 at the time of detecting a zero-cross point in the drive control method of the brushless motor drive control device of the first embodiment, and FIG. 7 is a flowchart of the brushless motor drive control device of the first embodiment. 9 is a flowchart illustrating a control operation of interrupt processing 2 by a phase difference detection unit of the drive control method.

First, a start-up operation at the time of power-on will be described with reference to FIG.

When the power is turned on, the zero-cross point extracting unit 201 sets the waveform processing flag J to 0 (zero-cross point not detected).
And the forced synchronization cycle control unit 207 sets the array number I to 0.
And the commutation control unit 208 sets the mode selection flag H to 0
(Compulsory synchronization mode), the commutation immediately after detection flag K is set to 0 (not immediately after commutation), the phase number M is set to 0, and the phase difference measuring section 210 sets the timer number flag P to 2 (timer is not started). State) (S1).

Next, the commutation control unit 208 and the forced synchronization cycle control unit 207 detect the rotation start signal input from the input unit 122 (S2), and the rotation start signal is in the LOW state (indicating that the operation is not permitted). If (state), step S2 is repeated, and the process waits (S3).

In step S3, the rotation start signal is H
In the case of the IGH state (a state indicating operation permission), the commutation control unit 208 detects the rotation direction determination signal input from the input unit 122, and the rotation direction determination signal is in the HIGH state (a state indicating the forward direction). Then, the six-phase control signal UH ₀ ,
UL ₀ , VH ₀ , VL ₀ , WH ₀ , and WL ₀ are sequentially switched in the forward direction. If the rotation direction determination signal is a LOW state (a state indicating the reverse direction), the six-phase control signal UH ₀ ,
UL ₀ , VH ₀ , VL ₀ , WH ₀ , and WL ₀ are sequentially switched in the reverse direction (S4). Here, the state in which the six-phase control signals are sequentially switched in the positive direction means that, when the commutation timing signal is input to the commutation control unit 208, the six-phase control signals are switched in the order shown in the column of “positive direction” in (Table 1). The state in which the control of the switching of the control signal is controlled is indicated. The state in which the six-phase control signal is sequentially switched in the reverse direction means that when the commutation timing signal is input to the commutation control unit 208, the “reverse direction” in (Table 1) "In the order shown in the column.

[0062]

[Table 1]

Next, the compulsory synchronization cycle control unit 207 clears the timer of the third time measurement timer 206, and gives the I (= 0) -th timing signal generation time T _co (I) to the third time measurement timer 206. Then, the timer of the third time measurement timer 206 is started (S5).

Next, the commutation control unit 208 sets the six-phase control signals UH ₀ , UL ₀ , VH ₀ , VL ₀ , WH ₀ so that the M (= 1) -th phase state shown in (Table 1) is obtained. switches the WL ₀ (S6), sets the commutation immediately detection flag K is 1 (S
7). The commutation immediately after detection flag K is a flag that is always set to 1 when the phase switching of the commutation control unit 208 is performed. As described later, this is a zero-crossing point generated at the rise or fall of a surge pulse. Used to remove

During this time, the third time measurement timer 206 starts
Counts the clock input from the
When the timing signal with the count value set is generated
Interval T _coIt waits until (I) is reached (S8).

When the count value reaches the timing signal generation time T _co (I), the third time measurement timer 206 sends the commutation timing signal (commutation pulse) to the forced synchronization cycle control unit 207 and the commutation control unit. 208, and phase difference measurement unit 2
The data is output to the device 10 (S9).

When the commutation timing signal is input from the third time measurement timer 206, the forced synchronization cycle control unit 207
Increases the sequence number I by 1, and the commutation control unit 208 increases the phase number M by 1 (S10).

At this time, in this embodiment, since the brushless motor is of six-phase control, when the phase number M becomes 6 (S11), the phase number M is returned to 0 (S12).

Thereafter, the operations from step S5 to step S12 are similarly repeated N times (S13).

Here, the timing signal generation time T
_co (I) is set to be shorter as the sequence number I increases from 0 to N-1. Thereby, the rotation speed of the brushless motor is increased and accelerated.

Six-phase control signal output from commutation control section 208
UH₀, UL₀, VH₀, VL₀, WH ₀, WL₀Drive
Source signal buffer unit 209, the commutator element
105 to perform switching of the commutator element 110
-Level control signals UH, UL, VH, V
L, WH, and WL, and the stator windings 102u, 10u
Drive current i flowing through 2v, 102w_u, I_v, I_wCut
Replacement is performed.

When the operations from step S5 to step S12 are repeated N times, I = N-1 is reached, and the operation shifts to the operation in the next switching mode (S13).

When shifting to the switching mode (see FIG. 4), the control unit 121 executes an interrupt process 1 upon detection of a zero-cross point and an interrupt process 2 by the second time measurement timer 205.
Are permitted.

First, the forced synchronization cycle control section 207 clears the count value of the third time measurement timer 206 and gives the third time measurement timer 206 the timing signal generation time T _co (N
-1) is set, and the timer of the third time measurement timer 206 starts counting (S21). Commutation control unit 2
08 is a six-phase control signal UH so as to be in the M-th phase state.
₀ , UL ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ are switched and latched (S22).

Next, the phase difference measuring section 210 checks whether or not the currently set timer number flag P is 2 (a state indicating that the timer has not started) (S2).
3) If P = 2, set P = 1 (a state indicating that the timer of the phase difference measurement unit 210 has been started by the third time measurement timer 206) (S24).

Here, since the current state is P = 2, P = 1 is set in steps S23 and S24.

Next, the phase difference measuring section 210 sets the currently set timer number flag P to 0 (phase difference measuring section 210
(A state indicating that the second timer is started by the second time measurement timer 205) is checked (S2).
5). If the interruption process is not performed, since P = 1 here, the phase difference measurement unit 210 clears the current timer count value and restarts the timer count (S26).

Thereafter, the commutation detection flag K is set to 1 (S27).

During this time, the third time measurement timer 206 counts the clock from the oscillation circuit 212, and waits until the count value reaches the set timing signal generation time T _co (N-1) (S28). ).

When the count value of the timer reaches the timing signal generation time T _co (N−1), the third time measurement timer 206 starts the forced synchronization cycle control unit 207 and the commutation control unit 20.
8. A commutation timing signal is output to the phase difference measurement unit 210 (S29). When the commutation timing signal is input from the third time measurement timer 206, the commutation control unit 208 increases the phase number M by 1 (S30).

At this time, since the brushless motor is under six-phase control, when the phase number M becomes 6 (S31),
The phase number is returned to 0 (S32).

Finally, the control switching unit 211 checks whether the mode selection flag H set in the commutation control unit 208 is 1 (feedback control mode) (S33), and H = 0.
If so, the operation returns to the operation in step S21.

Thereafter, the operations from step S21 to step S33 are repeated until switching from the forced synchronization mode (H = 0) to the feedback control mode (H = 1) by the interruption process 2 by the second time measurement timer 205.

Next, the operation of interrupt processing 1 upon detection of a zero-cross point will be described with reference to FIG.

The interrupt processing 1 upon detection of the zero-cross point is as follows:
This is performed when the comparators 120u, 120v, and 120w detect a change in the state of the zero-crossing point detection signals V _U0 , V _V0 , and V _W0 of any phase. That is, the interrupt processing 1 at the time of detecting the zero-cross point is processing performed when the zero-cross point due to the rise and fall of the surge pulse and the induced voltage is detected by the zero-cross point detection unit 120.

At the rise of the surge pulse, first, the zero-cross point extracting unit 201 checks whether the commutation immediately after detection flag K is 1 (immediately after commutation) (S51).
In the case of 1 (immediately after commutation), the waveform processing flag J is set to 1 (a state indicating that the rising of the surge pulse has been detected), and the immediately after commutation detection flag K is set to 0 (not immediately after commutation). (S52), the interrupt processing 1 ends (S5).
3).

When the surge pulse falls, first, the zero-cross point extraction unit 201 checks whether the commutation immediately after detection flag K is 1 (immediately after commutation) (S51). In step S52, since the commutation immediately after detection flag K is set to 0 (a state indicating that it is not immediately after commutation), the waveform processing flag J is increased by 1 and J = 2 (the fall of the surge pulse is detected). (S54). Next, the zero cross point extraction unit 201
It is checked whether J = 3 (zero cross point is detected) (S5).
5) Since J = 2, the interrupt processing 1 ends (S5).
6).

That is, from step S51 to step S5
By the above operation of No. 6, the zero-cross point extraction unit 201 ignores the zero-cross point due to the rise and fall of the surge pulse generated immediately after the commutation and outputs nothing.

At the time of detecting the zero-cross point by the induced voltage, first, the zero-cross point extraction unit 201 checks whether the commutation immediately after detection flag K is 1 (immediately after commutation) (S
51). At this time, since the commutation detection flag K is set to 0 (not immediately after commutation) in step S52 when the surge pulse rises, the waveform processing flag J
Is increased by 1 so that J = 3 (zero cross point is detected) (S54). Next, the zero-cross point extraction unit 201 determines that J =
3 (detection of zero crossing point) (S5).
5) Since J = 3, the waveform synthesizing logic unit 202a
The zero cross point detection signals V _U1 , V _V1 and V _W1 are output. The waveform synthesis logic unit 202a outputs the zero-cross point detection signals V _U1 , V _U1
When any one of _V1 and _VW1 is input, the current count value of the first time measurement timer 202b is stored in the zero-cross point time interval memory unit 203, and the first time measurement timer
After clearing the count value of the timer 2b to 0, the timer of the first time measurement timer 202b starts counting (S57). That is, by this operation, the time interval from the zero-cross point due to the immediately preceding induced voltage to the zero-cross point due to the current induced voltage is stored in the zero-cross point time interval memory unit 203.

Next, the waveform synthesizing logic unit 202a clears the count value of the second time measurement timer 205 and starts counting by the second time measurement timer 205 (S58).

Next, in the phase shift amount determination calculating section 204, the zero-cross point interval estimating section 204a reads the measured values of the N-th preceding zero-cross point time intervals stored in the zero-cross point time interval memory section 203, and reads those values. , An interval T _{0 (inf)} to the next zero-cross point is calculated, and the phase shift amount determination unit 204 b
In step S59, a 30-degree phase shift time T _{0 (inf)} / 2 or a 90-degree phase shift time 3T _{0 (inf)} / 2 is set.

Finally, the zero-cross point extracting unit 201 sets the waveform processing flag J to 0 (zero-cross point not detected),
The immediately after commutation detection flag K stored in the commutation control unit 208 is set to 0 (not immediately after commutation) (S60), and the interrupt process 1 ends (S61).

Next, interrupt processing 2 by the second time measurement timer 205 will be described.

The count value of the timer of the second time measurement timer 205 is the phase shift time (30 ° phase shift time T _{0 (inf)} / 2 or 30 ° phase shift time ₎ set in the second time measurement timer 205 by the phase shift amount determination calculation unit 204. When it becomes equal to the 90-degree phase shift time 3T _{0 (inf)} / 2), the interruption process 2 by the second time measurement timer 205 is performed. The interrupt processing 2 by the second time measurement timer 205 is performed when the commutation timing generated by the feedback of the zero-crossing point detection signals V _U1 , V _V1 , V _W1 becomes substantially equal to the commutation timing generated by the forced synchronization. After the control is switched to the feedback control, and after the switch to the feedback control, the phase of the base current is switched at the commutation timing of the phase shift time.

When the count value of the second time measurement timer 205 becomes equal to the phase shift time set in the second time measurement timer 205 by the phase shift amount determination calculation unit 204 in the forced synchronization mode (H = 0). First, the second time measurement timer 205 checks whether the mode selection flag H set in the commutation control unit 208 is 1 (feedback control mode) (S71), and at this time, H = 0.
Next, the second time measurement timer 205 checks whether the timer number flag P set in the phase difference measurement unit 210 is 2 (a state indicating that the timer has not started). (S72) When P = 2, P = 0 (a state indicating that the count of the phase difference measurement unit 210 has been started by the second time measurement timer 205) is set (S73).

If P = 2 (a state indicating that the timer has not started yet) in step S72, the second time measurement timer 205 sets the timer number flag P to 0 in step S73, and sets P ≠ 1 Judgment is made (S74), the count value of the timer of the phase difference measuring section 210 is cleared and counting is started (S75), and the interrupt processing 2 is ended (S76).

That is, from step S72 to step S75
In the case where the count of the timer of the phase difference measurement unit 210 is not started by the third time measurement timer 206, the count of the timer of the phase difference measurement unit 210 is started, and the interrupt process 2 ends.

When the second time measurement timer 205 starts counting of the timer of the phase difference measurement unit 210 by the operation of the above steps S71 to S76, and the interruption process 2 is completed, the process proceeds to step S25 in FIG.
= 0 (a state indicating that the timer of the phase difference measurement unit 210 has been started by the second time measurement timer 205), and then the phase difference measurement unit 210 starts the commutation generated by the second time measurement timer 205. A time difference (phase difference) ΔT ₂₃ between the timing signal and the commutation timing signal generated by the third time measurement timer 206 is detected and output to the control switching unit 211,
Control switching unit 211 determines whether the phase difference [Delta] T ₂₃ is the threshold value [Delta] T ₀ or less (S34).

If the phase difference ΔT ₂₃ has not reached the threshold value ΔT ₀ or less, the control switching unit 211 determines that the rotation of the brushless motor has not reached the synchronous state (S 34), and the timer of the phase difference measuring unit 210 The counting is stopped to clear the count value (S35), the timer number flag P is set to 2 (a state indicating that the timer has not been started) (S36), and the operation proceeds to step S27.

On the other hand, when the phase difference ΔT ₂₃ has reached the threshold value ΔT ₀ or less, the control switching unit 211 sets the mode selection flag H of the commutation control unit 208 to 1 (feedback control mode) (S37). Move on to the operation of S27.

In the interruption process 2 by the second time measurement timer 205, if the count of the timer of the phase difference measurement unit 210 has already been started by the third time measurement timer 206 when the interruption process 2 is started, step S72 Is determined to be P = 1 (a state indicating that the timer of the phase difference measurement unit 210 has been started by the third time measurement timer 206) (S74), and then the phase difference measurement unit 210 There outputs the commutation timing signal and detects the control switching unit 211 the phase difference [Delta] T ₂₃ between the commutation timing signal generated by the second time measuring timer 205 for generating a third time measurement timer 206, the control switching part 211 It is determined whether the phase difference ΔT ₂₃ has become equal to or smaller than the threshold value ΔT ₀ (S77).

If the phase difference ΔT ₂₃ has not reached the threshold value ΔT ₀ or less, the control switching unit 211 determines that the rotation of the brushless motor has not reached the synchronous state (S77), and the timer of the phase difference measuring unit 210 counts. Is stopped to clear the count value (S78), and the timer number flag P is set to 2 (a state indicating that the timer has not started) (S78).
79), the interrupt process 2 ends (S76).

When the phase difference ΔT ₂₃ has reached the threshold value ΔT ₀ or less, the control switching unit 211 sets the mode selection flag H of the commutation control unit 208 to 1 (feedback control mode) (S80), and executes interrupt processing 2 Is completed (S76).

After the mode selection flag H of the commutation control unit 208 is set to 1 (feedback control mode), the count value of the second time measurement timer 205 is calculated by the phase shift amount determination calculation unit 204 for the second time measurement. Timer 205
When the second time measurement timer 205 again performs the interruption process 2 by the second time measurement timer 205, the second time measurement timer 205
Determines that H = 1 (feedback control mode), sets the commutation detection flag K of the commutation control unit 208 to 1 (immediately after commutation) (S81), and the commutation control unit 208 sets the phase number M Control signals UH ₀ , UL ₀ , VH ₀ , VL ₀ , W
The states of H ₀ and WL ₀ are switched and latched (S82). Next, the commutation control unit 208 increases the phase number M by 1 (S8).
3) At this time, since the brushless motor is under six-phase control, when the phase number M becomes 6 (S84), the phase number is returned to 0 (S85), and the interrupt processing 2 is ended (S84).
76).

When H = 1 (feedback control mode) is set by the above operation, in step S33, the control switching unit 211 determines that H = 1 (feedback control mode), and switches to the next feedback control mode. Move on to operation.

As described above, when the timing of the commutation timing signal generated by the third time measurement timer 206 and the timing of the commutation timing signal generated by the second time measurement timer 205 in the forced synchronous control state substantially coincide with each other. Then, the state shifts from the forced synchronization control state to the feedback control state.

In the feedback control mode, the commutation control unit 208 detects the rotation start signal input from the input unit 122, and if the rotation start signal is in the LOW state (operation is not permitted) (S38), Six-phase control signals UH ₀ , U
The phase switching of L ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ is stopped, and the brushless motor is stopped (S39).

At step S39, the commutation control unit 20
8 returns to step S38 again when the rotation start signal is in the HIGH state (operation permission state).

During this loop, the zero-cross point detector 1
If the zero-cross point is detected by 20, the operation of the interrupt processing 1 upon detection of the zero-cross point is performed, and the count value of the timer of the second time measurement timer 205 is changed by the phase shift amount determination calculation unit 204 to the second time measurement timer 205. When the phase shift time is equal to the set phase shift time, interrupt processing 2 by the second time measurement timer 205 is performed.

In the operation of the interruption process 2 by the second time measurement timer 205, since the mode selection flag H is 1 (feedback control mode), step S71 is performed.
Thereafter, the operation moves to the operation of step S81, and the operation up to step S76 is performed. That is, in the feedback control mode, in the interrupt processing 2, only the six-phase control signal UH
Only the phase switching operations of ₀ , UL ₀ , VH ₀ , VL ₀ , WH ₀ , WL ₀ are performed.

Next, a method of predicting and calculating the phase shift time by the phase shift amount determining operation unit 204 will be described.

FIG. 8 is a diagram showing the phase relationship between the six-phase control signal and the zero-crossing point detection signal. FIG. 9 shows the change in the zero-crossing point interval in a state where the rotation speed is reduced by the load applied to the rotating shaft of the brushless motor. FIG.
FIG. 5 is a diagram illustrating a change in a zero-cross point interval in a state where the number of rotations increases due to a load applied to a rotating shaft of a brushless motor.

In FIG. 8, UH, UL, VH, VL,
WH and WL are six-phase control signals, V _U , V _V , and V _W are terminal voltages, A is a zero-crossing point due to an induced voltage generated in the stator windings 102u, 102v, and 102w, and B is a commutation point (for a surge pulse). (Rising point), E is the falling point of the surge pulse.

In FIGS. 9 and 10, A is a zero-cross point due to the induced voltage, which corresponds to the zero-cross point A due to the induced voltage in FIG. t ⁽⁰⁾ is the current time, t ₀ is t ⁽⁰⁾ time at which the zero-crossing point A occurs due to last to the induced voltage in the past of time _{than, t - k (k = 1,2,3} , ··
.) Is the time when the zero-crossing point A due to the induced voltage last occurred at a time point earlier than the time t _{-k + 1} , and t _k (k = 1,
2, 3,...) Is the time at which the zero-crossing point A due to the induced voltage is first generated at a time later than the time t _-k-1 , and the discrete function T _k (k = 0, 1, 2, 3,. ...) the time t _-k from t _{- (k-1} time _interval) (ie, the interval point of the zero-crossing time k or prior to the current _{T k = t -k + 1 -t} -k), T 0 (inf ₎ Is a phase shift amount determination calculation unit 20 at a zero-cross point time interval from the time t ₀ to the first zero-cross point occurring after the time t.
4 is the estimated value. When the load applied to the rotating shaft of the brushless motor increases, as shown in FIG. 9, the interval between occurrences of the zero cross point A due to the induced voltage increases with time. Conversely, when the load applied to the rotating shaft of the brushless motor decreases, as shown in FIG. 10, the interval between the occurrence of the zero cross point A due to the induced voltage decreases with time.

The first time measurement timer 202b generates a zero-crossing point time interval T _k (T _k (T _k )) based on a signal generated by the waveform synthesizing logic part 202a according to the zero-crossing point detection signals V _U1 , V _V1 , V _W1 detected by the zero-crossing point extraction part 201. k =
, 1, 2, 3,...) Are measured and sequentially stored in the zero-crossing point time interval memory unit 203. Accordingly, at time t ⁽⁰⁾ , the zero-crossing point time interval memory unit 203 stores the zero-crossing point time interval T _k (k = 1, 2, 3,...).

The phase shift amount determination calculation unit 204 firstly
The zero-cross point time interval T _k (k = 0, 1, 2, 3,...) Stored in the zero-cross point time interval memory unit 203
Read out.

Next, the phase shift amount determining operation unit 204
The zero-crossing point time interval T _{0 (inf)} from time t ₀ to the next zero-crossing point is determined by _(Equation 7), and the second time measurement timer 205 sets the 30-degree phase shift time T _{0 (inf)} / 2 or 9
0 degree phase shift time 3T _{0 (in f)} / 2 is set.

[0118]

(Equation 7)

The second time measurement timer 205 has a count value of the timer, the 30-degree phase shift time T _{0 (inf)} / 2 or the 90-degree phase shift time 3T _{0 (inf )} set by the phase shift amount determination calculation unit 204. ₎ / 2, a commutation timing signal is output. That is, the second time measurement timer 2
05 corresponds to time T ₀ from time t ₀ in FIG. 9 or FIG.
_{0 (inf)} / point B ₃₀ delayed by / 2 or time 3 from time t ₀
A commutation timing signal is output at a point B ₉₀ delayed by T _{0 (inf)} / 2. Accordingly, even when the rotation speed of the brushless motor changes due to the load applied to the rotating shaft, it is possible to accurately estimate a point (time) that is phased by 30 degrees or 90 degrees from the zero cross point at time t ₀ , and an appropriate The commutation timing can be obtained.

Here, in (Equation 7), the phase shift amount determination calculation unit 204 uses the first derivative of the time-varying zero-cross point time interval series T ₁ , T ₂ , T ₃ ,. Although the time interval T _{0 (inf)} to the point is estimated, the zero-cross point time interval T
_{As a} method of estimating _{0 (inf)} , a time-varying zero-crossing point time interval series T ₁ , T ₂ ,
The prediction may be performed using the second derivative of T ₃ ,.

[0121]

(Equation 8)

Further, more generally, the phase shift amount determining operation unit 204 calculates n of the time-varying zero-crossing point time interval sequences T ₁ , T ₂ , T ₃ ,. Time interval T _{0 (inf)} to the next zero crossing point using the second derivative
May be estimated.

In equation (6), A _k (r) (k, r =
0, 1, 2,...) Are coefficients when the k-th derivative is converted into a backward differential expression, and are represented by recurrence expressions such as (Expression 4) and (Expression 5). Specifically, the values are as shown in (Table 2).

[0124]

[Table 2]

As described above, the phase shift amount determining operation unit 20
4 is n past zero-crossing point time interval sequences T ₁ ,
By determining an estimated value T _{0 (inf)} of the next zero-crossing point time interval from T ₂ , T ₃ ,..., T _n , even if the rotation speed of the brushless motor changes due to the load on the rotating shaft, It is possible to accurately estimate a point (time) shifted by 30 degrees or 90 degrees from the zero-cross point at time t ₀ , and to obtain an appropriate commutation timing.

Here, the meaning of (Equation 6) will be supplementarily described.

The zero-crossing point time interval series T ₁ , T ₂ ,
T ₃ ,..., T _k ,... Are regarded as discrete functions of k (k is an index representing time), and at least an n-order differentiable real number x continuous function f (x), T _k = f (-K)
(K = 0, 1, 2,...). At this time, when f (x) is approximated by Taylor expansion up to n-order around x = x ₀ , the following equation (9) is obtained. Here, -Δf _err ⁽ⁿ⁾ in ⁽ Equation 9) represents an error due to approximation.

[0128]

(Equation 9)

In equation (9), x ₀ = −1, Δx ₀ = 1
Then, (Equation 10) is obtained.

[0130]

(Equation 10)

In equation (10), f ′ (− 1), f ″
By approximating (−1),... With the backward difference, f ′ (−
1) = T ₁ −T ₂ , f ″ (− 1) = (T ₁ −T ₂ ) − (T _{2
-T 3) = T 1 -2T 2} + T 3, ··· , and the then substituted into the approximate expression of the equation (10), by the Δf _{e rr} ⁽ⁿ⁾ = 0 is (6) is derived You. That is, (Equation 6) is
Zero crossing point time interval sequence _{T 1, T 2, T 3} , regarded as a discrete function of the ... time, approximate expression of the continuous function f (x) interpolating the discrete function is approximated by a Taylor expansion formula of n th order Is a backward difference approximation.

Further, the phase shift amount determining operation unit 204
Time t Time t _-1 value T ₁ that estimates the zero crossing point time interval T ₁ of the zero-cross point and the zero cross point at time t ₀ in _(inf) actually measured zero crossing point time interval between T ₁ immediately after the _-1 calculating the estimated T _{0 (inf)} difference _{ΔT e rr = T 1 -T 1} (inf) is stored and the time t ⁽⁰⁾ following the zero crossing point time interval T ₀ in the equation (11) with May be configured.

[0133]

[Equation 11]

This makes it possible to determine the estimated value T _{0 (inf)} of the next zero-crossing point time interval with higher accuracy, and to obtain more appropriate commutation timing.
In particular, when the rotational speed of the brushless motor repeats deceleration and acceleration, Δf _err ⁽ⁿ⁾ ignored in the approximation from (Expression 10) in approximation from (Expression 10) may be large and the error may be large. , (Equation 11), the error can be reduced even in the above case by predicting T _{0 (inf)} .
Conversely, when T _{0 (inf)} is predicted by _(Equation 11), the degree of approximation n is smaller than that in the case of predicting T _{0 (inf)} by _(Equation 6), and is about the same as that of (Equation 6). Proper T _{0 (inf)}
Can be predicted.

[0135]

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

According to the first aspect of the present invention, an appropriate commutation timing can be obtained even when a sudden change in the number of revolutions occurs due to a change in the load applied to the rotating shaft of the brushless motor, and step-out occurs. It is possible to provide a drive control device for a brushless motor that can prevent the operation of the brushless motor. In addition, since commutation is performed at an appropriate timing, high current resistance is not required for electric parts, and it is possible to configure the electric parts with low current resistance and inexpensive parts. Can be provided.

According to the second aspect of the present invention, since the change in the number of revolutions is numerically captured by a function, the brushless motor drive capable of estimating the time interval up to the next zero crossing point of the induced voltage. A control device can be provided. In addition, since the time interval from the previously detected zero-cross point interval to the next zero-cross point is estimated, even if the next zero-cross point is not detected under the influence of noise, the drive current It is possible to provide a drive control device for a brushless motor capable of performing the phase switching. Furthermore, by using the differential value of the series of the zero-crossing point time intervals, it is possible to provide a brushless motor drive control device capable of accurately capturing the acceleration component of the rotation speed.

According to the third aspect of the present invention, a drive control device for a brushless motor capable of estimating a time interval up to the next zero crossing point of an induced voltage with an accuracy corresponding to the processing capability of the control unit. Can be provided. Also,
Since the time interval to the next zero-cross point is estimated by using the time interval of the zero-cross point up to the past n times and the expansion formula up to the n-th derivative of the series of the time interval of the zero-cross point, the brushless motor By determining the value of n in accordance with the load characteristics (the characteristics of the number of rotations with respect to the torque) and the load object, it is possible to provide a drive control device for a brushless motor capable of performing optimal control.

According to the fourth aspect of the present invention, the estimated value T _{1 (inf)} of the interval to the zero cross point of the previous induced voltage is different from the actual interval T ₁ to the zero cross point of the previous induced voltage. Can be fed back to the estimation of the interval T ₀ to the next induced voltage zero crossing point, so that it is possible to provide a brushless motor drive control device capable of coping with rapid repetition of acceleration and deceleration.

According to the fifth aspect of the present invention, there is provided a drive control device for a brushless motor capable of accurately estimating a time at which a phase shift amount of an induced voltage from a zero-cross point becomes 30 degrees or 90 degrees. can do. Also,
Since phase switching is performed at appropriate timing, acceleration /
It is possible to provide a brushless motor drive control device that can prevent the motor from stepping out and the motor current from sharply increasing even during deceleration.

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

According to the sixth aspect of the present invention, even when a sudden change in the rotational speed occurs due to a change in the load applied to the rotating shaft of the brushless motor, it is possible to obtain an appropriate commutation timing, and to step out. It is possible to provide a drive control method of a brushless motor that can prevent the operation of the brushless motor. Further, since the phase switching is performed at an appropriate timing, it is possible to provide a drive control method for a brushless motor that can prevent the motor from stepping out or a sharp rise in the motor current even during acceleration / deceleration.

According to the seventh aspect of the present invention, since the change in the number of revolutions is numerically captured as a function, the brushless motor drive capable of estimating the time interval up to the next zero crossing point of the induced voltage. A control device can be provided.

[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 functional block diagram of a control unit in FIG. 1;

FIG. 3 is a flowchart showing an operation at the time of startup of a drive control method of the drive control device for the brushless motor according to the first embodiment;

FIG. 4 is a flowchart showing an operation when switching from forced synchronous control to feedback control in the drive control method of the brushless motor drive control device according to the first embodiment;

FIG. 5 is a flowchart showing an operation at the time of feedback control of the drive control method of the brushless motor drive control device according to the first embodiment;

FIG. 6 is a flowchart illustrating a control operation of interrupt processing 1 when detecting a zero-cross point in the drive control method of the drive control device for the brushless motor according to the first embodiment.

FIG. 7 is an interrupt process 2 by the phase difference detection unit in the drive control method of the drive control device for the brushless motor according to the first embodiment.
Flow chart showing the control operation of

FIG. 8 is a diagram illustrating a phase relationship between a six-phase control signal and a zero-cross point detection signal.

FIG. 9 is a diagram illustrating a change in a zero-cross point interval in a state where the number of rotations is reduced by a load applied to a rotating shaft of a brushless motor.

FIG. 10 is a diagram showing a change in a zero-cross point interval in a state where the number of rotations increases due to a load applied to a rotating shaft of a brushless motor.

FIG. 11 is a diagram showing a method of determining a commutation timing from a zero cross point of an induced voltage in a drive control device for a brushless motor disclosed in Japanese Patent Publication No.

[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 122 Input unit 201 Zero cross point extraction unit 202 Zero cross point interval measurement unit 202a Waveform synthesis logic unit 202b First time measurement timer 203 Zero cross point time interval Memory unit 204 Phase shift amount determination operation unit 204a Zero cross point interval estimation unit 204b Phase shift amount determination unit 205 Second time measurement timer 206 Third time measurement timer 207 Forced synchronization cycle control unit 208 Commutation control unit 209 Drive base signal buffer unit 210 phase difference measurement unit 211 controls switching unit 212 oscillator V _N neutral potential _{V U,} V V, V _W terminal voltage _{V U0, V V0, V W0} , V U1, V V1, V W1 zero-crossing point detection signal UH, UL, VH, VL, WH, WL, UH ₀ , UL ₀ ,
VH ₀ , VL ₀ , WH ₀ , WL ₀ Six-phase control signal i _u , i _v , i _w Driving current H Mode selection flag I Array number J Waveform processing flag K Commutation detection flag M Phase number P Timer number flag ΔT ₂₃ Timing time difference ΔT ₀ threshold value T _co (I) Timing signal generation time

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H560 BB04 BB07 BB12 DA13 DB20 DC02 EB01 EC10 GG04 SS01 TT01 TT02 XA05 XA15 XB09 XB10

Claims (7)

[Claims] 1. A brushless motor for controlling a brushless motor comprising: a plurality of stator windings connected at one point; and a permanent magnet rotor 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 drive current supplied to the stator winding by switching phases of the commutator elements, and a terminal voltage of each stator winding. A zero-cross point detection unit that detects a zero-cross point crossing a reference voltage and outputs a zero-cross point detection signal corresponding to each of the stator windings; and a phase of the drive current of the drive circuit based on the zero-cross point detection signal. A control unit that controls switching, wherein the control unit is configured to control the fixed one of the zero-cross points detected in the past by the zero-cross point detection signal. Zero-crossing point time interval estimating means for estimating the time interval from the zero-crossing point of the induced voltage induced in the winding to the next zero-crossing point of the induced voltage; A phase shift amount determining a delay time from a zero crossing point of the induced voltage detected last in the past to a point at which the drive current is switched based on an estimated value of a time interval to the zero crossing point of the induced voltage. Means for switching the phase of the drive current by delaying the drive current by delaying from the zero cross point of the induced voltage last detected in the past by the delay time. apparatus. 2. The zero-crossing point time interval estimating means sets a time interval of a zero-crossing point of the induced voltage detected in the past as a discrete function of time, and uses a differential value of the discrete function to calculate the next induced voltage. The drive control device for a brushless motor according to claim 1, wherein a time interval up to the zero cross point is estimated. 3. k and r are constants of 0 or more, i is an integer of 1 or more, n is any integer constant of 1 or more, and the time when the zero crossing point of the induced voltage was last detected in the past is defined as t
_0, and time t _{-i + 1} before the time when the zero-cross point is detected in the last the induced voltage and t _-i, the time interval of the zero-crossing point in the past of the induced voltage T _i = t - _{i + 1} −t _−i, and the time interval T until the next zero crossing point of the induced voltage
The estimated value of ₀ is defined as T _{0 (inf)} , the coefficient A _k (r) is defined as a constant defined by _(Equation 1) and (Equation 2), and the zero-crossing point time interval estimating means performs the calculation of (Equation 3) Is performed, the time interval T ₀ up to the next zero crossing point of the induced voltage is obtained.
2. An estimated value T _{0 (inf) of the first} parameter is determined.
Or a drive control device for a brushless motor according to 2. (Equation 1) (Equation 2) (Equation 3) 4. A time interval T to a next zero-cross point of the induced voltage estimated by the zero-cross point time interval estimating means.
₁ estimates T _{1 (inf)} actually detected error [Delta] T _err between the time interval T ₁ of the up zero-cross point of the next of said induced voltage =
Error detection storage means for detecting and storing T ₁ -T _{1 (inf)} ;
By adding the error ΔT _err detected and stored last in the past by the error detection storage means to the time interval T ₀ to the next zero cross point of the induced voltage estimated by the zero cross point time interval estimation means, Estimation value correction means for correcting the estimated value of the time interval up to the zero-cross point of the induced voltage, wherein the phase shift amount determination means comprises a zero-cross point of the next induced voltage corrected by the estimated value correction means. 4. The brushless apparatus according to claim 3, wherein a delay time from a zero-cross point of the induced voltage detected last in the past to a phase switching of the drive current is determined based on an estimated value of a time interval until the brushless operation. Motor drive control device. 5. The apparatus according to claim 1, wherein said phase shift amount determining means determines, as said delay time, 1/2 or 3/2 times an estimated interval of said induced voltage to a zero crossing point. Item 5. A brushless motor drive control device according to any one of Items 1 to 4. 6. Each of said stator windings of a brushless motor comprising: a plurality of stator windings connected at one point; and a permanent magnet rotor rotationally driven by a magnetic field generated by each of said stator windings. A drive control method for a brushless motor that is energized and driven by performing phase switching synchronized with rotation of a wire, wherein an induced voltage induced in each of the stator windings by rotation of the permanent magnet rotor is a reference. A zero cross point of the induced voltage crossing the voltage is detected, a time interval of the zero cross point of each of the induced voltages is detected, and the induced voltage of the induced voltage detected next from the zero cross point of the induced voltage detected last in the past is detected. Estimate the time interval to the zero cross point from the time interval of the zero cross point of the induced voltage detected in the past,
Based on the estimated time interval to the next induced voltage zero-cross point, determine the delay time from the last detected zero-cross point of the induced voltage until the phase switching is performed, and the last detected delay in the past A drive switching method for the brushless motor, wherein the drive current is phase-switched with a delay of the delay time from the zero-cross point of the induced voltage. 7. A time interval of a zero cross point of the induced voltage detected in the past as a discrete function of time, and a time interval to the next zero cross point of the induced voltage is estimated by using a differential value of the discrete function. 7. The drive control method for a brushless motor according to claim 6, wherein: