JPS5893487A - Brushless dc motor - Google Patents

Abstract

PURPOSE:To reduce the number of parts and manufacturing steps of a brushless DC motor by controlling the operation of the second drive transistor group at the energizing state time so that the operating voltage of the second drive transistor group at the energizing state time becomes the prescribed value. CONSTITUTION:The first drive transistor groups 26-28 respond by the first distribution controller 102 to the outputs of Hall elements 15-17, and receive energization control by a voltage/current converter 105 which inputs the current detection voltage from a resistor 21 and a command signal 60 and a differential circuit 104. The second distribution controller 103 responds to the outputs from Hall elements 18-20, the second drive transistor groups 46-48 are controlled in energization via a differential circuit 108 by the output of a comparator 107 which compares the operation voltage detection signal at the energizing state time of the second drive transistor groups 46-48 from an operation detector 106 with the reference voltage signal, and the reduction of the operation voltage is compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pushless DC motor that electronically switches the power supply to multiple phase coils in accordance with the position of a movable part of the motor.

Brushless DC Motor Co., Ltd. has a small torque clip of 1%, no noise caused by brushes, and has a long life.
It is applied to various audio equipment. Special public show 6M-695
Publication No. 8 states that in such a pushless DC motor, current is passed in both directions to the six-phase coil connected in a star shape (
It is disclosed that the use efficiency of the coil can be improved by using a full-wave drive. According to this, a first transistor group supplies a constant current to the multiphase coil, and a second transistor group controls the potential at a common connection point of the multiphase coil to a predetermined value. Ru.

However, in such a configuration, in addition to the terminal that supplies current to the coil, the common connection terminal (required simply to detect the voltage) must also be drawn out from the motor side and connected to the circuit element. The number of wires increased, making manufacturing complicated.

Taking these points into consideration, the present invention provides a pushless DC motor that achieves stable and reliable full-wave drive by wiring only the terminals that supply current to the multiphase coils (no need for common connection terminal wiring). It is something to do.

Configuration of pushless DC motor according to the present invention! a position detection means for detecting the position of the movable part; a multi-phase coil; a first drive transistor group for supplying current to the coil; and a first drive transistor group responsive to the output of the position detection means. a first distribution control means for distributing and controlling the energization of the coil, a second drive transistor group inserted in series in a current path formed by the coil and the first drive transistor group, and a second drive transistor group that responds to the output of the position detection means. The energization of the second driving transistor group is distributed and controlled, and the transistor IO operating voltage in the energized state of the first driving transistor group is detected, and the energization of the third driving transistor group is controlled accordingly. The present invention is characterized by comprising a second distribution control means for controlling the operating state of the transistor depending on the state.

The present embodiment will be described below based on the drawings. 1st
The figure is an electrical circuit wiring diagram showing one embodiment of the present invention.

In Fig. 1, 01) is a field magnetic field attached to the rotor), (Ill (14 is a star-connected five-phase coil group, w(2) (2) is a second drive transistor group, -@- is the second driving force group, (2) is a resistor for detecting the combined supply current to the coil 055 H041. Also, the part (101) surrounded by the broken line is the magnef) (Ill. Hall element e@- that senses magnetic flux
(1?) a position detector constituted by 6101-;
(102) is a first distribution controller that distributes and controls the energization of the corresponding first drive transistor group (2) in response to the output of the Hall element 051 on aη; (105)
is a second distribution controller that distributes and controls the energization of the corresponding second drive transistor group -@- in response to the output of the Hall element tll01-.

Next, its operation will be explained. When 12V is applied to the power supply voltage Vcc, the voltage drop across the resistor (2) and the command voltage signal are compared in the voltage/current converter (105), and a current corresponding to the difference between the two is output. Differential circuit (104)
t- is supplied as a common emitter current of the constituent transistors (to) (2). Transistor (2) (foundation)
(2) Each base terminal has a Hall element 0510
An output voltage of 1'611η is applied, and the common emitter current is distributed to each collector current according to the difference in base voltage, and the collector current of the transistor with the lowest base voltage is the largest, and the collector current of the other transistors is Zero or almost zero.

Tofunjis! @(2) Each frefter current of (2) is the first
It becomes each pace current of the drive transistor group @ @ (to), and the current is amplified and the coil 0 smell 0! l 114. The current supplied to coil 021 @3 and 4 is resistor 6! υ
is detected as a voltage drop in the voltage/current converter t1ob
input to the inverting input terminal of the main unit.

As a result, the voltage/current converter (105), the 10th differential circuit (104), and the first drive transistor group
(2) and the resistor @ constitute a first feedback loop (current feedback loop), and the current supplied to the coil (121a row I) reliably becomes a constant current value corresponding to the command signal -. A capacitor @ is interposed between the inverting input terminal and the output terminal of the converter (106) for the purpose of phase compensation of the above-mentioned feedback loop.

(This capacitor (2) is connected to the voltage/current converter (106)
It doesn't matter if you connect it between the output and the power supply terminal. ) Figure S shows an example of the configuration of the voltage/current converter (106).
Compare the voltage of the signal - with the voltage of the resistor @p using the transistor ゛υ and the resistor ■, and convert it into a current corresponding to the difference,
Transistor! The current is inverted by the current circuit 1- and output.

Next, the operation of the second distribution controller and the second drive transistor group will be explained. Second distribution control 1ill device (10
! S) is an operation detector (106) that detects the operating voltage of the transistor in the energization state of the second drive transistor group m171 (C), which detects the collector-emitter voltage VCE in this embodiment. , the predetermined voltage value Vref determined by the resistor (b) and the constant current source -B4@・Eng4・(
A ratio articulator (107) that compares the output voltage of the motion detector (lLlfl) and the output voltage of the motion detector (lLlfl) and sucks a current corresponding to both, and a second differential circuit (108) IICX
It is structured as follows.

Figure 2 shows the drive transistor and the current path when @ is active. From Figure 2, the current path is from the ■ side power source → the power supply → the coil tJa and the Q:l
→ Transistor V) → Resistor ■ → θ side power supply, and the terminal voltage of coil Q'B becomes larger than the terminal voltage of coil 031+141 1. As a result, the diode axis becomes conductive and the other diodes @- are non-conductive. So, *I轡detectorq
The output voltage A of 06) is the operating voltage vct of the 29th drive 1 transistor that is turned on, and the -direction of the rediode (2)! The lower the VD, the larger the value (considering from the power supply terminal).

The output voltage A of the moving zone detector (106) is the comparator (H17)
is applied to the base of the transistor so. On the other hand, a predetermined voltage value Vrθf is applied to the emitter side of the transistor by a constant current source and a resistor.

Therefore, the transistor member essentially compares vCE and Vref (towards the diode axis) and the forward voltage between the base and emitter of the transistor is canceled out), and a collector current flows according to the difference, and the current due to the transistor ring It is inverted in the mirror circuit, and the 20th differential circuit (1
08).

The output of the Hall element (II 01) is applied to each base terminal of the transistor @-1 of the differential circuit (108), and the common emif I current is collected according to the pace voltage.
to be distributed. Transis! Each collector current of @-1 becomes each base current of the second drive transistor ---, the current is amplified, and energization to the coil 923 Ql f14 is switched and controlled.

Therefore, a motion detector (106), a comparator (107),
A second feedback loop is configured by the second differential circuit (108) and the second drive transistor group -@-, and the operating voltage VCI f activation of the transistor in the energized state of the second drive transistor group -@- Predetermined voltage value Vre within the area
It operates to match f. To further explain this, the decrease in the operating voltage of the second drive transistor is detected by the motion detector (106) and is detected by the comparator II.
(107) to reduce the sink current of the second drive transistor, thereby reducing the base current and therefore the collector current of the second drive transistor;
As a result, the operating voltage of the second drive transistor increases.

If such a feedback loop is applied, the second differential circuit (
10g) and the second drive transistor group -m- are stable, and the switching of the energizing transistors in response to the output of the position detector (101) is performed reliably and smoothly.

Also, its relative voltage Vref 0'41.4. is Vce
It can be set sufficiently small compared to carp/L/(15
Although the voltage drop at 5Ql +141 is large by 9, the first drive transistor is in the active region and is difficult to saturate.

Note that the capacitor is provided for phase compensation of the feedback loop mentioned above. Also, the capacitor @eAt) @ and the resistor @ connected to the coil 010N140 terminal
The O series circuit is used to reduce the spike voltage caused by switching of the energizing path.

In the above-mentioned embodiment, an example was shown in which the S-phase coils/L' were connected in a star shape, but the present invention is not limited to such a case, and can generally constitute a motor having multiphase coils. In addition, the drive transistor is not limited to the Bybov type transistor.
It goes without saying that a field effect transistor may also be used. Furthermore, the configurations of the motion detector, comparator, etc. are not limited to the above embodiments, and various hairstyles are possible without changing the gist of the present invention.

As described above, according to the present invention, the operating voltage of the transistor in the energized state of the second drive transistor group is detected, and the operating voltage of the transistor in the energized state of the second drive transistor group is adjusted so that the detected voltage becomes a predetermined value. Since we control the
Connection to the motor coil! The number of 9 children may be small, and the number of parts and IiI manufacturing man-hours are reduced. Furthermore, due to the reduction in the number of connections between the drive circuit and the coil, the number of output bins will also be reduced if, for example, the circuit of FIG. 1 is configured with a one-chip integrated circuit.

Therefore, based on the present invention, it is possible to obtain a device with good performance at a low cost by using a Lunara that constitutes a pushless DC motor for audio equipment or Fi video equipment.

[Brief explanation of drawings]

The first WA is an electrical circuit diagram representing an embodiment of the present invention;
Figure 1 is a diagram to explain its operation.
It is a diagram showing an example of the configuration of a current toilet exchanger. ltl)m+Y4/*y), 11!11
13th fist 4-:1 I'le, m r:;a m-...10th
Drive transistor group, -@-...Second drive transistor group, (10t)--Position detector, (102)...
First distribution controller, (101)--Second distribution controller, (104)--First differential circuit, (10M)--Voltage/current converter, (1G41)...Operation Detector, (1
07)... Comparator, (1011) - Tsutsuyuki's differential circuit agent Yoshihiro Moritei Figure 2 Figure 5 ¥21

Claims (1)

[Claims] L: a position detection means for detecting the position of the motor movable part; a multi-phase coil; a first drive transistor group for supplying current to the coil; and a first drive transistor in response to the output of the position detection means. a first distribution control means for distributing and controlling energization of the transistor group; a second drive transistor group inserted in series in a current path formed by the coil and the first drive transistor group; and a second drive transistor group responsive to the output of the position detection means. Mt that distributes and controls the energization of the second drive transistor group.
distribution control means, and the second distribution control means includes an operation detection means for detecting an IO operating voltage that turns the second drive transistor group into a energized state, and the operation detection means Said according to the output of the means! The operation state of the transistors in the energized state of the drive transistor group is controlled at nine brushless DC motors.