JPS63121489A - Brushless motor control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a brushless motor, and more particularly to a control device for starting and controlling a three-phase brushless motor driven by two-phase excitation. (Prior Art) In a control device for a three-phase brushless motor, for example, a commonly known brushless motor equipped with a three-phase stator and a four-pole permanent magnet rotor, the rotational position of the rotor is Three Hall elements are provided to detect A signal for switching the excitation phase of the two stators for each rotation was generated by logically processing three phase signals from the Hall elements.However, in the brushless motor control device using the Hall element described above, In order to generate the excitation phase switching signal, it was necessary to perform logic processing many times, and the circuit configuration or processing program to execute this became complicated.Therefore, instead of the Hall element, we installed it on the output shaft of the motor. Using an optical sensor that detects the slits in the rotor plate, three phase signals with a pulse width of 60 degrees or 120 degrees are generated with a phase difference of 60 degrees, and the excitation is switched every 30 degrees of the rotor. The three phase signals are directly used as a signal to switch the excitation of one of the two stators, and the signal to switch the excitation of the other stator is used as a signal to switch the excitation of the other stator. A possible method is to generate the slits by counting the number of slits according to the rotation of the rotor.This method reduces the computational processing load for generating excitation switching signals in the motor control device, and ensures accuracy even when the motor is running at high speed. (Problem to be Solved by the Invention) However, in the brushless motor control device using the optical sensor described above, when starting the motor, three phases from the optical sensor are detected. Although the stator that should be excited for one stator can be identified by the signal, the stator that should be excited cannot be identified for the other stator because the motor is not rotating and passing through the many slits described above cannot be detected. Therefore, if the other stator is energized incorrectly, the motor cannot be started and the starting of the motor becomes uncertain. (Objective of the Invention) The object of the present invention is to A three-phase brushless motor that is driven by two-phase excitation by switching the excitation state of the excitation pole every 30 degrees using three sets of phase signals with a phase difference of 60 degrees or 120 degrees and a speed pulse signal. An object of the present invention is to provide a control device for a brushless motor that can reliably start the motor. (Means for Solving the Problems) As shown in the functional block diagram of FIG. 1, the brushless motor control device according to the present invention has a phase difference of 60 degrees depending on the rotation of the rotor of a three-phase brushless motor. and a speed detection means for generating a speed pulse signal having a frequency proportional to the rotational speed of the brushless motor. 0 in the 3-phase stator of the motor
A brushless motor control device that switches an excitation phase pattern for exciting a two-phase stator in a predetermined order every 30 degree rotation of the rotor, and controls the rotational speed of the brushless motor to a desired speed according to the speed pulse signal. The speed detection means is configured such that the level of the speed pulse signal changes every 30 degrees of rotation of the rotor of the brushless motor, and the level change is synchronized with the level change of the phase signal, Initial setting control means is provided for determining the levels of the phase signal and speed pulse signal at the time of generation of the starting command to set an excitation phase pattern at the initial stage of starting. Note that, if necessary, the initial setting control means may include a discriminating means for discriminating between the levels of two specific phase signals among the three phase signals and the level of the speed pulse signal, and a predetermined series of discriminating means. The apparatus may be configured to include an excitation phase pattern selection means for selecting one excitation phase pattern from among a large number of excitation phase patterns according to the determination result of the determination means. (Function) In the brushless motor control device according to the present invention,
The phase signal generating means generates 60 degrees or 12 degrees with a phase difference of 60 degrees depending on the rotation of the rotor of a three-phase brushless motor.
Three phase signals with a pulse width of 0 degrees are generated, a speed pulse signal with a frequency proportional to the rotational speed of the brushless motor is generated by the speed detection means, and the three phase signals of the brushless motor are detected based on these three sets of phase signals. The excitation phase pattern for exciting the two-phase stator in the stator is controlled to switch in a predetermined order every 30 degrees of rotation of the rotor, and the rotational speed of the brushless motor is controlled to a desired speed according to the speed pulse signal. Ru. When starting the brushless motor, the initial setting control means determines the levels of the phase signal and speed pulse signal and sets the excitation phase pattern at the initial stage of starting, so that the brushless motor is reliably started. (Effects of the Invention) According to the brushless motor control device according to the present invention, as explained above, at the time of starting the brushless motor, based on the phase signal and the level of the speed pulse signal that changes every 30 degrees of rotation, Since the excitation phase pattern at the initial stage of startup is set, the brushless motor is reliably started with a strong torque, and since the rotation of the rotor is accelerated after startup, the time required for the rotation speed to rise is shortened. (Example) Hereinafter, an example of the present invention will be described based on the drawings. As shown in FIG. 2, this embodiment has a four-pole permanent magnet rotor 1 in which S poles and N poles are alternately arranged, and three excitation poles U-
This is a control device for controlling a three-phase, four-pole brushless motor M consisting of a three-phase stator 2 having V-W by two-phase excitation, and particularly relates to a control device characterized in starting control of the motor M. It is connected to the rotating slit plate 3 which is fixed to the motor shaft 1a of the rotor 1 and rotates with the rotation of the rotor 1.
A phase sensor 5U, a V-phase sensor 5v corresponding to the V-phase excitation coil 4■, and a rotation pulse sensor 6 for optically detecting the rotation speed and rotation angle of the brushless motor M are provided to start the brushless motor M. U phase sensor 5U at
The W-phase signal Sw is synthesized from the U-phase sensor signal 5ua outputted from the V-phase sensor signal 5v and the V-phase sensor signal Sv outputted from the V-phase sensor 5v, and control is performed based on these signals S1, 5v-5W and the rotation pulse signal SII. This is what I did. When the motor M is started, in the rotation range of the rotor 1 of 60 degrees indicated by the signal states of the U-phase sensor signal SU and the ■-phase sensor signal Sv, when the rotation pulse signal SR is at the "L" level, the first half of the rotation range is 30 degrees. The excitation phase pattern of 30" is set as the initial excitation phase pattern, and when the rotation pulse signal SR is at the "H" level, the excitation phase pattern of 30" in the latter half is set as the initial excitation phase pattern.
This is to ensure that the . As shown in Fig. 2, the brushless motor M has an S pole and an N pole.
A four-pole rotor 1 with alternating poles, U phase, ■ phase,
It is composed of a three-phase stator 2 of W phase, U phase, V phase, W phase.
Excitation coils (hereinafter referred to as a U-phase coil 4U, a V-phase coil 4, and a W-phase coil 4W) are wound around each phase in the same manner as in the existing brushless motor M. The excitation angle for exciting each phase coil of the U-phase coil 4U-V-phase coil 4V-W-phase coil 4W of the brushless motor M is the interphase angle of the U phase, V phase, and W phase, as shown in FIG. From 120° which is 9 to 9 which is the opening angle of each magnetic pole of rotor l
0" is subtracted from 30@ as a unit angle. In the case of one-phase excitation, the unit angle is 30 degrees, and in the case of two-phase excitation, it is 60 degrees, which is twice the unit angle. When the three-phase stator 2 is controlled by two-phase excitation, as shown in FIG.
- It is necessary to have different polarity combinations of N and S poles on the W side, such as U phase N pole - V phase S pole, U phase N pole - W phase S pole, ■ phase N pole - W phase S pole , V-phase N pole-tJI'ls pole, WIIIN pole-U-phase S pole, and W-phase N pole-V-phase S pole. Therefore, the direction of current corresponding to the six combinations is U
Phase → V phase, U phase → W phase, V phase → W phase, ■ phase → U phase, W phase → U phase, W phase → ■ phase, U phase coil 4U-V phase coil 4V-W phase It is necessary to selectively switch the direction of the current for the coil 4W, and the direction of the current can be switched using two types of transistors UA that are part of the driver shown in Figure 4.
・Controlled by switching vA-WA・U, -V, and -W, respectively. As shown in FIG. 3, the rotary slit plate 3 is a circular metal plate fixed to the motor shaft 1a, and has a 30° curved slit 7 on its outer periphery for detecting speed and rotation angle. Six curved slits 8U are formed at intervals, and on the inner circumferential side of the slits 7, a pair of curved slits 8U extending over an angle of 60' for the U finger sensors 5U are symmetrical with respect to the axis of the motor shaft 1a. 60 mm on the inner circumferential side of this slit 8U.
A pair of curved slits 8v for the finger sensors 5, extending over an angle of The arrow 9 indicates the forward rotation direction of the brushless morph M. At one point in the circumferential direction of the rotary slit plate 3, the plane A U-shaped sensor mounting block 10 is provided to sandwich the rotary slit plate 3 in a non-contact manner, and this sensor mounting block 10 includes a light emitting element (such as a photodiode) and a light receiving element (such as a phototransistor). Three sets of photosensors are connected to each of the slits 7, 8U, 8■
They are installed in such a way that they correspond to each other. As shown in FIG. 5, from the rotating balsa sensor 6 corresponding to the slit 7, a rectangular pulse-shaped rotating pulse signal S1 repeats "L" level and "H" level every 30 degrees.
1 is output, and the U finger sensor 5U corresponding to the slit 8U and the ■finger sensor 5■ corresponding to the slit 8■
Inverters 15 and 16 are interposed in the output lines of the U-phase sensor 5U and the U-phase sensor signal Su, which becomes "L" level when facing the slit 8U, is output from the finger sensor 5V. When facing slit 8V r L J
The phase II sensor signal Sv, which is the level, is output. Next, a control device for controlling the brushless morph M will be explained based on the block diagram of FIG. 4. This control device includes a start/stop switch (STPSW) 26 for starting/stopping the motor M, a rotary slit plate 3, the sensors 5U/5V/6, inverters 15/16, a NAND gate 17, a speed command section B, and a control section C. It consists of a driver section. The start/stop switch 26 is activated only when it is operated.
Return type 0N10FF that outputs “L” level signal ST
This signal ST is output to the phase switching circuit 27. In the phase switching circuit 27, this signal ST is input to the terminal CK of a JK flip-flop (not shown), and a start/stop control signal 5TP is output from the output terminal Q.
C is output to register 30. The register 30 holds this start/stop control signal 5TPC while outputting a gate signal GS substantially the same as this signal to the AND gate 22. That is, each time the start/stop switch 26 is operated, the signal 5TPC and the gate signal GS are alternately inverted to rHJ level and "L" level signal, and when the signal is "H" level, the brushless morph M is activated. Rotationally driven. The rotation pulse signal SII from the rotation pulse sensor 6 is transmitted to the one-shot multivibrator 21 and the phase switching circuit 2.
7, enable terminal EN of the pulse width calculator 32, and A
It is output to the input terminal of the ND gate 22, and the AND gate 2
A clock signal CL of 500 KH is input to the input terminal of the AND gate 22, and the output line of the AND gate 22 is connected to the clock terminal CK of the speed detection counter 23. Furthermore, the one-shot multi-by-break 21 outputs a trigger signal T1 every 60'' at the rising edge of the rotation pulse signal S. The speed detection counter 23 counts the clock signal CL when the rotation pulse signal St input to the AND gate 22 and the gate signal GS are both rl (J level). The counted value, that is, the speed detection signal N, is output to the pulse width calculator 32. That is, when the rotation pulse signals S and l are at the rH level, the speed detection counter 23 counts the clock signal CL and outputs the speed signal N. Due to this, the speed detection counter 23
is reset by the trigger signal T1 every 60'' output at the timing of the rise of the rotation pulse signal SR. The speed command section B is composed of a potentiometer 14, etc.
The selected signal is converted into a speed command signal NO by the A/D converter 33 and then output to the pulse width calculator 32. In the pulse width calculator 32, the speed of the brushless morph M is controlled by pulse width modulation based on the speed signal N input from the speed detection counter 23 and the speed command signal NO input from the A/D converter 33. Pulse width for (
Driver part includes PNP transistor UA/V
- The pulse width of the positive excitation control pulse applied to WA is calculated at the timing of every 60 falling edges of the rotation pulse signal S8, and the pulse width signal PWS is temporarily stored in the register 31 and is also applied to the gate circuit 34U. It outputs 34V and 34W respectively. That is, the pulse width signal PW stored in the register 31
S is updated every 60'' with the latest calculated pulse width signal PWS. The U-phase sensor signal SLI from the U-phase sensor 5U is sent to the one-shot multipipe rake 18 and the NAND gate 17.
The V-phase sensor signal Sv from the V-phase sensor 5■ is outputted to one input terminal of the one-shot multi-by-break 18, the other input terminal of the NAND gate 17, and the phase switching circuit 27. This NAN
The D gate 17 receives the U-phase sensor signal Su and the V-phase sensor signal S.
The NAND gate 17 outputs the W-phase signal Sw (see FIG. 5) from the NAND gate 17 to the one-shot multivibrator 18 and the phase switching circuit 27. The one-shot multivibrator 18 outputs a trigger signal at the falling edge of each of the U-phase sensor signal S0, the ■-phase sensor signal Sv, and the W-phase signal Sw. The output lines of the books are respectively connected to the input terminals of the OR gate 19, and from the OR gate 19 the phase angle 6
The trigger signal for each 0° (see Figure 5) is sent to the phase switching circuit 27.
Signal T, to. is output as The phase switching circuit 27 receives the signal T from the OR gate 19,
. Based on the trigger signal T s i from the one-shot multi-by-break 21 and the rotation pulse signal SR, U
This is for switching and controlling the excitation of the phase coil 4U, the ■phase coil 4v, and the W-phase coil 4W. The phase switching circuit 27 is connected to the CPU (central processing unit) and the RO.
M (read-only memory) and RAM (random
As shown in Fig. 6, this ROM has three types of positive excitation phase patterns P1, Pl, and Pm3 that positively excite any of the phase coils 4U, 4■, and 4W. Positive excitation data Da and each phase coil 4U・4V・
Reverse excitation phase pattern Pb+- that reverse excite any of 4W
Three types of reverse excitation data D, Pbt-P, 3, are stored. 3 types of forward excitation data D1 and 3 types of reverse excitation data D
, "1" indicates the excitation phase and rQJ indicates the non-excitation phase, and the positive excitation data D of the pattern P□・P@t'Pm'J,
are respectively U phase coil 4U, ■ phase coil 4V-W phase coil 4
The reverse excitation data Db of the pattern PbI-Pbz-Pb3 specifies the excitation of the V-phase coil 4, the V-W phase coil 4W, and the U-phase coil 4U, respectively. The excitation phase pattern of the motor is determined by the combination of the forward excitation phase pattern P□・P, 2・P83 and the reverse excitation phase pattern Phi・PItl'Pb3, but for the forward excitation data D, the signal T P for each input of so, →
The reverse excitation data D is switched in the order of Pat→pus→P1, and the reverse excitation data D is switched in the order of PbI=Pb2→Pb2→P0 every time the trigger signal T s i is input. The switching control of the patterns during starting and driving of the motor M will be described later based on the flowchart of FIG. 7, and a control program for this switching control is stored in the ROM. The phase switching circuit 27 outputs forward excitation data D to the register 28 and reverse excitation data Db to the register 29. The register 28 temporarily stores the positive excitation data D1 and also stores the positive excitation data D. However, when the pattern is P1, the U-phase positive excitation signal Gu is output to the U sum gate circuit 34U, and the pattern pH! When , ■ Output the phase positive excitation signal Gv to the V sum gate circuit 34V,
In the case of pattern Pm3, the W-phase positive excitation signal Gw is output to the W-sum gate circuit 34W. On the other hand, in the register 29, the reverse excitation data Db is temporarily stored, and the reverse excitation data Db is stored in the pattern P.
When the pattern is b3, the U-phase excitation signal CCu@outputs to the base of the U-phase transistor U8, when the pattern Pbl, the phase excitation signal CCv is output to the base of the phase ■ transistor, and when the pattern pbz, the W-phase reverse excitation is performed. The signal CCw is output to the base of the W-phase transistor W3. When the U-sum gate circuit 34U receives the U-phase positive excitation signal Gu, the gate opens and the pulse width signal PWS is output to the U-phase counter 35.
It is output to the preset terminal PR3 of U. This means that the V sum gate circuit 34V and the W sum gate circuit 3
The same goes for 4W. ■ When the sum gate circuit receives the V-phase positive excitation signal Gv, the pulse width signal PWS is output to the V-phase counter 3.
5V is output to terminal PR3, and the W sum gate circuit also outputs W
Upon receiving the positive phase excitation signal G8, the pulse width signal PWS is output to the terminal PR3 of the W-phase counter 35W. Next, the U-phase counter 35U is a subtraction counter, and receives the pulse width signal pws from the U sum gate circuit 34U, a clock signal CL of 500 KH at its terminal CK, and a clock signal CL of 2 KH at its load terminal LD. Upon receiving the clock signal, the U-phase counter 35U sets the pulse width every time it receives a load signal of 2KH, and by counting the clock signal CL, the pulse width commanded by the pulse width signal PWS is subtracted. It continues to be output to a certain U-phase positive excitation count signal Ku@U-phase discrimination circuit 36U. This means that the ■phase counter 35V and the W phase counter 35V
The same goes for W, and the V-phase counter 35■ outputs the phase positive excitation count signal Kv to the phase discrimination circuit 36V, and the W-phase positive excitation count signal Kw is output from the W-phase counter 35W to the W phase discrimination circuit 36W. is output. The U-phase discrimination circuit 36U is composed of an OR gate, a one-shot multi-by-break, and an RS flip-flop, and discriminates whether the U-phase positive excitation count signal Ku from the U-phase counter 35U is 0 (the U-phase coil 4U is set to U-phase positive excitation count signal K for positive excitation by cycle
This is a circuit for stopping the excitation of the U-phase coil 4U when u is 0, and the positive excitation count signal Ku from the U-phase counter 35U is input to the OR gate, and the output signal of the OR gate is passed through the one-shot multi-by-break. A clock signal of 2KH is input to the terminal R of the RS flip-flop, and the U-phase positive excitation control pulse Pu from the output terminal Q is input to the base of the U-phase transistor UA. is output to. That is, the "L" level U-phase positive excitation control pulse Pu, which falls every time the clock signal of 2KH is inputted and rises when the U-phase positive excitation count signal Ku reaches 0, is applied to the U-phase transistor UA.
is output to the base of This means that ■phase discrimination circuit 36V and W phase discrimination circuit 36W
The same goes for the “L” level V that rises when the falling V-phase positive excitation count signal Kv reaches 0 for each clock signal.
The phase positive excitation control pulse Pv is output to the base of the phase transistor ■, and the W-phase positive excitation control pulse at the "L" level rises when the falling W-phase positive excitation count signal Kw reaches 0 every clock signal. Pw is output to the base of the W-phase transistor W^. The above U-phase coil 4U, ■phase coil 4■, and W-phase coil 4W
The driver section for the above-mentioned PNP) transistor UA'Va''WA and the NPN transistor U,
■, ・Wa and high frequency diode D1u-D1v-Dl ・Dzu' as a flywheel diode
It is composed of Dzv-Dzw. Regarding the U-phase, the emitter of the transistor UA is connected to a DC power supply, the collector of the transistor UA is connected to the collector of the transistor U, and one end of the U-phase coil 4U is connected to the connection point. Connect diode D between the emitter and star as shown.
It+ is connected, a diode [)zu is connected as shown between the emitter and collector of the transistor U3, and the emitter of the transistor U3 is grounded. This is the same as above for the ■ phase and W phase, and the ■ phase coil 4 is connected to the connection point of the V phase transistors VA and VB.
One end of V is connected, and W phase transistors Wa and W
One end of the W-phase coil 4W is connected to the connection point of 3.
The U-phase coil 4U, the V-phase coil 4■, and the W-phase coil 4W are star-connected. For example, as in the case of a phase angle of 15° in FIG.
When the U-phase positive excitation control pulse Pu is applied to the base of the U-phase transistor Us, and the V-phase common excitation signal CCv is applied to the base of the ■phase transistor ■, the transistor UA has a duty ratio corresponding to the pulse width signal PWS. The current from the DC power supply is turned on and off so that
The flow goes from V to transistor ■ to ground, and the U-phase coil 4U is positively excited and the V-phase coil 4V is reversely excited. Then, as the duty ratio increases (pulse width increases), the conduction time of the transistors UA'VA and WA of each phase becomes longer, and the pulse width modulation causes each phase coil 4U and 4
The current flowing through v·4W increases, and the rotational speed of the brushless morph M increases. At this time, each time the transistor UA chops from ON to OFF, current flows in the same direction as before through the U-phase coil 4U and V-phase coil 4■ due to self-induction.
This induced current flows along the circuit of U-phase coil 4U - V-phase coil 4v → transistor V → diode Dzu- + U-phase coil 4U, and current flows continuously between U-phase coil 4U and V-phase coil 4V. Become. That is, the flywheel diode D zu-D zv
-I) zw is provided for pulse width modulation. Furthermore, when the ■phase transistor V is switched from ON to OFF, the self-induced current flows from U-phase coil 4U to V-phase coil 4.
v→diode D r v"" U-phase transistor UA
- Since the self-induced current flows along the circuit of the +U phase coil 4U, the self-induced current is effectively utilized. Next, switching control of the excitation phase pattern at the time of starting and driving the brushless morph M will be explained with reference to the flowchart of FIG. 7, but first a brief overview thereof will be given. As can be seen from FIG. 5, the combinations of the U-phase sensor signal Su and the V-phase sensor signal Sv and the positive excitation phase patterns corresponding to each combination are as shown in Table 1. Table 1 When starting the motor M, the positive excitation phase pattern P0 and Pat"Pa according to the combination of the signal Su and the signal Sv (signal state B)
3 is determined, but there are two possible reverse excitation phase patterns Pbl'pbz・Pb3 for each signal state.
For example, phase angle 0! ~60°, the first half of 30° is a pattern P in which V-phase coil 4 is reversely excited (Db: 01
0), and the pattern Pbt (Db: 001) is that the W-phase coil 4W is reversely excited in the latter half of 30°. Therefore, based on the signal level of the rotation pulse signal S, it is possible to determine whether it is the first half of 30' or the second half of 30 degrees. That is, as shown in Table 2 below, when the rotation pulse signal SL1 is at the "L" level, it is at the first half of 30 degrees, and when rH
, level is the latter half 30'', so the initial excitation phase pattern at startup can be set based on the signal level of each phase sensor signal Su'Sv and rotation pulse signal SII+.Table 2 Next, the above-mentioned The steps of the startup control performed by the phase switching circuit 27 will be explained with reference to the flowchart in FIG. Steps are handled in the same way), initial settings are performed and S2
Move to. In S2, it is determined whether or not the start/stop switch 26 has been operated. If it has not been operated, the process moves to S3. The start/stop control signal 5TPC is set to 0, which is written to the register 30, and the process proceeds from S3 to 32.
Steps S2 and S33 are repeated at minute intervals, and when the start/stop switch 5TPSW26 is operated, the step moves to S34. In S4, the start/stop control signal 5TPC is set to "1", and this start/stop control signal 5TPC is written into the register 30 and held. In the next step 35, it is determined whether the rotation pulse signal SR is at the "L" level, and if it is not at the "L" level, the
When the level is "L", the process moves to S6. In the next step 56, it is determined whether the U-phase sensor signal Su is "1" or not, and when it is "1", the process moves to S8 and the signal is "1" again.
If not, the process moves to S7. In S7, it is determined whether the V-phase sensor signal Sv is "1" or not. When it is "1", the process moves to S9, and when it is not "1", the process moves to SIO. Further, in S8, it is determined whether or not the V-phase sensor signal Sv is "l", and when it is "rl", the process moves to S11 and "
If the value is not 1, the process moves to SIO. S9 is, for example, when the phase angle in FIG. 5 is 0° to 30°, and the forward excitation data D is set to a pattern P□ that excites the U-phase coil 4U, while the reverse excitation data Db is set to a pattern P□ that excites the U-phase coil 4U. The pattern Pbl is set to excite 4■.
SIO is, for example, when the phase angle in FIG. The pattern pbt is set to excite the coil 4W. Sll is, for example, when the phase angle is 120° to 150° in FIG.
is set to pattern Pb3 that excites the U-phase coil 4U. In the next step 312, the forward excitation data Da and reverse excitation data Db, which are the initial excitation phase patterns set in S9.310.311, are output, and the U-phase coil 4U, V-phase coil 4■, and W-phase coil 4W are output. is forwardly excited or reversely excited in accordance with the forward excitation data D and reverse excitation data D, and as a result, the rotor 1 starts to start, and the process moves to 320. On the other hand, in S5, when the rotation pulse signal SR is not at the "L" level, that is, when it is at the rHJ level, the process moves to 313. The following 313 to 315 are the same as S6 to S8 above, and U
a step of setting an initial excitation phase pattern according to the signal states of the phase sensor signal Su and the V-phase sensor signal Sv,
In 313, it is determined whether the U-phase sensor signal Su is "1" or not, and when it is "1", the process moves to 315 and the signal is "1"
If not, the process moves to 314. In step 314, it is determined whether or not the V-phase sensor signal Sv is "1".
If not, the process moves to S17. Further, in S15, it is determined whether the V-phase sensor signal Sv is "1" or not. When it is "1", the process moves to S18, and when it is not "1", the process moves to S17. 316, for example, if the phase angle in FIG.
0゛, and the positive excitation data D is U-phase coil 4U.
The reverse excitation data D, on the other hand, is set to a pattern Pb2 that excites the W-phase coil 4W. In S17, for example, if the phase angle in FIG.
20°, and the positive excitation data D1 is for phase coil 4.
The reverse excitation data D, on the other hand, is set to a pattern Pb3 that excites the U-phase coil 4U. In S18, for example, if the phase angle in FIG.
180°, and the forward excitation data D is set to a pattern P that excites the W-phase coil 4W, while the reverse excitation data D is set to a pattern P that excites the V-phase coil 4v. In the next step 319, the forward excitation data D and reverse excitation data Db set in S16 to 318 are output, and the U-phase coil 4U, ■ phase coil 4■, and W-phase coil 4W output the forward excitation data D and reverse excitation data D. The rotor 1 is forwardly excited or reversely excited in accordance with the excitation data D, and thereby the rotor 1 starts to start, and the process moves to S20. The next 320 to S21 is the pattern P1 of the positive excitation data D.
・This is a step of sequentially shifting P at 'P m3 (see FIG. 5), and in S20 the OR gate 19
It is determined whether the output signal T3° is "1" or not, and when it is "1", the process moves to S21, and when it is not "1", the process moves to S21.
Move to 2. At 321, the forward excitation data D of the pattern shifted by one is output to the register 28, and the reverse excitation data D is output to the register 29. The next 522 to S23 are patterns Pb of reverse excitation data Db.
This is a step of sequentially shifting Pbt-Pbx (see Fig. 5), and in S22 it is determined whether the trigger signal TS! of the one-shot multivibrator 21 is "1", and if it is "1", the process advances to 323. Migrate and also '
1", the process moves to S24. In S23, the reverse excitation data D of the pattern shifted by one is output to the register 29, and the forward excitation data D is output to the register 28. In the next step 324, it is determined whether the start/stop switch 26 has been operated (or not to stop the rotation of the rotor 1), and if it has not been operated, the process moves to S20, and 52
By repeating steps 0-32-4, the rotor 1 is continuously driven to rotate, and when the rotor 1 is operated, the process moves to S25. In S25, the start/stop control signal 5TPC is set to "0" and written to the register 30, and as a result, the gate signal C3 becomes "L" level, the operation of the speed detection counter 23 is stopped, and the rotor 1
Prepare to stop rotating. In the next step 326, forward excitation data and reverse excitation data Db that do not excite any phase coil are set. In the next step 327, the forward excitation data D1 set in 326 is stored in the register 28, and the reverse excitation data D is stored in the register 29.
The rotation of the rotor 1 is stopped, and the process moves from S27 to S32. As explained above, in the control device for the brushless motor M of this embodiment, the W-phase signal Sw is synthesized with the U-phase sensor signal Su and the ■-phase sensor signal Sv, thereby omitting the W-phase sensor and An initial excitation phase pattern for starting the rotor l is set based on the signal states of the phase sensor signal Su, the ■phase sensor signal Sv, and the rotation pulse signals S and I, and the rotor is reliably started using this initial excitation phase pattern. I can do it. Note that this example merely shows one example of the present invention.
Those skilled in the art can make various modifications without departing from the spirit of the invention. Note that the control section C may be configured with a microcomputer or the like. Furthermore, what are the restrictions when reversing the brushless motor M? Regarding II, this is possible by sequentially shifting the excitation phase patterns of the forward excitation data D and the reverse excitation data D in a direction opposite to the forward rotation. Note that the rotational speed of the brushless motor M is controlled by pulse width modulation, similar to existing DC motors.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of a control device for a brushless motor according to the present invention, Figs. 2 to 7 show embodiments of the control device for a brushless motor, and Fig. 2 is a vertical cross-section of essential parts of the brushless motor. Figure 3 is a front view of the rotating slit plate and three sets of sensors, Figure 4 is a configuration diagram of the brushless motor control device, and Figure 5 is the sensor signal of each phase and the excitation and reverse excitation of each phase coil, etc. FIG. 6 is an explanatory diagram illustrating the pattern of forward excitation and reverse excitation of each phase coil when starting the brushless motor, and FIG. 7 is a flowchart of the brushless motor startup control routine performed by the control device. be. M...Brushless motor, 1...Rotor, 1a...
Motor shaft, 2. Stator, U, ■, W... U-phase, ■-phase, and W harmonic magnetic poles, respectively, 3. Rotating slit plate,
4U, 4■, 4W, respectively U phase coil, V phase coil, W
Phase coil, 5U/5■... U phase sensor/■ phase sensor, respectively, 6... Rotating pulse sensor, 7... Curved slit, 8U/8V... Curved slit, respectively, 1
7...NAND gate, 21...One-shot multi-by-break, 23...Speed detection counter, 26...
Start/stop switch, 27... Phase switching circuit, 28...
Register, 29...Register, 32...Pulse width calculator, 33...A/D converter, 35U/35V/35
W...Counter for each phase, B...Speed command section, C
...Control section, D...Driver section, Ua" Va
'WA...PNP transistor for each phase, U
,・■3 ・W, ・NPN) transistor for each phase, D, UD, v・DIM・ ・Diode, D
2U-D! V-Dzw...Diode, Dl...
Forward excitation data, Db... Reverse excitation data. Patent applicant: Brother Industries, Ltd.] □Nico Figure 1

Claims (2)

[Claims] (1) Phase signal generating means for generating three phase signals having a pulse width of 60 degrees or 120 degrees with a phase difference of 60 degrees according to the rotation of the rotor of a three-phase brushless motor, and the rotational speed of the brushless motor. and speed detection means for generating a speed pulse signal with a frequency proportional to the frequency, the excitation phase pattern for exciting two of the three-phase stators of the brushless motor is set in a predetermined order every 30 degrees of rotation of the rotor. and controlling the rotational speed of the brushless motor to a desired speed according to the speed pulse signal, wherein the level of the speed pulse signal changes every 30 degrees of rotation of the rotor of the brushless motor. The speed detecting means is configured such that the level change is synchronized with the level change of the phase signal, and the speed detecting means is configured to determine the level of the phase signal and the speed pulse signal at the time of generation of the start command of the brushless motor to detect the initial start of the brushless motor. 1. A control device for a brushless motor, comprising initial setting control means for setting an excitation phase pattern. (2) The initial setting control means includes a determining means for determining the level of two specific phase signals among the three phase signals and the level of the speed pulse signal, and a predetermined series of a large number of excitation phases. 2. The control device for a brushless motor according to claim 1, further comprising excitation phase pattern selection means for selecting one excitation phase pattern from patterns according to the determination result of said determination means.