JPS5893486A - 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 first 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 controler 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 first drive transistor groups 26-28 from an operation detector 106 with the reference voltage signal, and the reduction of the operating voltage of the first transistor groups 26-28 is compensated for the decrease in the operating voltages of the second drive transistor group 46-48 and is increased.

Description

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

Brushless DC motors have small ripples, no noise caused by plastic V, and have a long lifespan, so they are used in various audio equipment. Japanese Patent Publication No. 66-6938 discloses that in such a brushless DC motor,
It is disclosed that current is passed in both directions (full-wave drive) to an S-phase coil with a K-shaped connection wire to improve the utilization efficiency of the coil. According to this, a first transistor group supplies a constant current to a multiphase coil, and a second transistor group controls the potential at a common connection point of the multiphase coils to a predetermined value. There is.

However, in such a configuration, in addition to the terminal that supplies current to the coil, the common connection terminal (required simply for detecting the voltage) must also be brought out from the MoI side and connected to the circuit element. However, the number of wires increases, making manufacturing complicated.

The present invention is a pushless DC motor that takes into account the I:Lt-consideration and 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 provides:

The configuration of the pushless DC motor according to the present invention includes a position detection means for detecting the position of the MoI movable part, a multi-phase coil, and a first drive transistor that supplies current to the coil. a first distribution control means for controlling current distribution of the first drive transistor group in response to the output of the position detection means, and inserted in series in a current path formed by the coil and the first drive transistor group. a second group of drive transistors that are connected to the drive transistors; and a transistor that controls energization of the second group of drive transistors in response to the output of the position detecting means, and a transistor that is in the energized state of the first group of drive transistors; detects the operating voltage of the second drive F and accordingly detects the operating voltage of the second drive F
Runjis! Operating state of transistors in group energized state 0
The present invention is characterized by comprising a second distribution control means for controlling.

An embodiment of the present invention 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, (Ill is a field magnet attached to the rotor, 1as- is a star-connected S-phase coil group, -@(2) is a first drive transistor group, -m- is the second drive transistor group, (2) is Coil A/ (1!
Hall element 051 that senses the magnetic flux of +ill
A position detector composed of on vehicle 010, (1
02) is a first distribution controller that distributes and controls the energization of the corresponding first swing transistor group (2) in response to the output of the Hall element O1IQ@(lη, and (103) is a Hall element This is a second distribution controller that distributes and controls the energization of the corresponding drive transistor group of -2 in response to the output of the element -(l@.11.knee).

Next, its operation will be explained. When 12V is applied to the power supply voltage Vcc, the electron drop across the resistor and the command voltage signal are compared in the voltage/current converter u06), a current corresponding to the difference between the two is output, and the first differential Concave W! I (104)
It is supplied as a common emitter current of transistors @94 (to) constituting the . An output voltage of a Hall element a0 (1-Oη) is applied to each base terminal of the transistor @@(2), and the common emitter current is distributed to each collector current according to the difference in base voltage, and the highest base voltage The collector current of the low transistor is the largest, and the collector currents of the other transistors are zero or almost zero.

The respective currents of the transistors (to) @(to) become the base currents of the first drive transistor group @@(2),
The current is amplified and supplied to the coil (1210304).

Coil 0! IO! The current supplied to I (141) is detected as a voltage drop across the resistance gradient, and the voltage/current converter (105
) is input to the inverting input terminal.

As a result, the first feedback loop (
current feedback loop) is configured and the coil ax as 04
The current supplied to 1 will surely be a constant current value corresponding to the command signal -. It should be noted that a capacitor gradient is interposed between the inverting input terminal and the output terminal of the -voltage/current converter (105) for the purpose of phase compensation of the above-mentioned feedback loop.

(This capacitor (2) is connected to a voltage/voltage converter (10
15) and between the output and the power supply terminal. ) 3rd
The figure shows an example of the configuration of the voltage/current converter ti06).
Here, the voltage of the signal - and the voltage of the resistor (2) are compared by the transistor #Il and the resistor (2), and the difference is converted into a current corresponding to the difference.The current is inverted by the current mirror circuit of the transistor and output.

Next, the operation of the second distribution controller and the second group of disturbance transistors will be explained. Second distribution controller (x Os)
The operation detector (106) that detects the operating voltage of the transistors, the constant current source, the diode, and the resistor are connected to the first drive F transistor group (E) @ (to) in the energized state. , a comparator (10'/1) that makes a differential ratio between the reference voltage value determined by the resistor (2) and the output voltage of the operation detector (106), and draws a current corresponding to both; It is composed of a differential circuit (108).

Fig. 2 shows the current path when the drive transistor and (2) are active. and 03
→ Tofunjis I @ → Resistor (2) - becomes the ○ side power supply, and the terminal voltage of the coil 13 becomes smaller than the terminal voltage of the coil 02104. As a result, the diode Cl5- becomes conductive, the other diode Cl5- becomes non-conductive, and the output voltage A of the operation detector (108) changes from the tenth drive transistor (108) in the conductive state.
2) The sum of the operating voltage VCR (collector-emitter voltage) and the voltage drop across the resistor (2) increases by the forward voltage VD of the diode.

The output voltage A of the operation detector a06) is applied to the base side of the differential transistor I of the comparator (107).

On the other hand, the base side of the differential transistor 4 is connected to a predetermined voltage value VrefmV D+R4l from the common connection point (emitter side) of the first drive transistor group (V)@ by means of a constant current source ring, a diode (2), and a resistor. A reference voltage value larger by I4a is applied. Therefore, transistor II and @
The operating voltage v of the first driving transistor is
Cx and the predetermined voltage value R4K, (usually aav-ta
(approximately
8).

The output of the Hall element 0 barrel (II-) is applied to each base terminal of the F transistor @- of the 1M dynamic E path (108),
The common collector current is distributed to the collector according to its base voltage. Each collector current of the transistor @@4WJ becomes each base current of the second drive transistor group -@-, and switches and controls energization to the current amplification coil α2) ai41.

Therefore, the operation detector (ctoa), the comparator (107), the 20th differential circuit (108), the second drive transistor group -
A second feedback loop is formed by @-, and the operating voltage VCXt of the transistors in the energized state of the first driving transistor group (2) vJ@ is set to a predetermined voltage M in the active region.
・Engineering. It works to match.

To further explain this, the 10th drive function I
The decrease in the O operating voltage is detected by the operation detector (106) and causes the sink current of the comparator (107) to increase and
The operating voltage (
Vct) is decreased, and as a result, the operating voltage of the first drive transistor is increased.

If such a feedback loop is implemented, the operation of the second differential circuit (108) and the second drive transistor group -m- will be stabilized, and the current-carrying transistors responsive to the output of the position detector (101) will be stabilized. Switching occurs reliably and smoothly.

Also, since the comparison voltage Vr@f can be set sufficiently smaller than Vcc, the coil 021 Q! Even if the voltage drop across l 041 is quite large, the second drive transistor is in the active region and is less likely to saturate.

In addition, the capacitor @, @ and the resistor @- connected to the phase C axis terminal of the feedback loop mentioned above for capacitor 1
The series circuit reduces the spike voltage caused by switching the energization path.

In the above-mentioned embodiment, an example was shown in which five-phase coils were connected in a star shape, but the present invention is not limited to such a case, and can generally be configured to a motor having multi-phase coils. Furthermore, it goes without saying that the drive transistor is not limited to the bipolar type transistor I, but may also be a field effect type transistor.
Furthermore, the configurations of the motion detector, comparator, etc. are not limited to those of the above-mentioned embodiment P, 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 U of the first driving transistor group is detected, and the operating voltage of the transistor in the energized state of the second driving transistor group is detected so that the detected voltage becomes a predetermined value. Operation status! Since I is controlled, the number of connection terminals to the coil of the soter can be reduced, and the number of parts and manufacturing man-hours can be reduced. Furthermore, due to the reduction in the number of connections to the drive circuit and the coil, the number of output pins will also be reduced if, for example, the circuit of FIG. 1 is configured as a one-chip integrated circuit.

Therefore, based on the present invention, audio equipment or video IN
If a dexterous pushless DC motor is constructed, a device with excellent performance can be obtained at low cost.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit connection diagram showing one embodiment of the present invention, FIG. 2 is a diagram for explaining its operation, and FIG. 5 is a side view of the configuration of a voltage/current converter. 1111-ff Gnet, (1!l us 114”
-""Il, @ @ em-... 10th drive F rungs I group, (14 (IIJ--... 2nd drive G')>S
) group I, (101)--position detector, (102)
-...first distribution controller, (105) -...second distribution controller, (104)...first differential circuit, QO6)
...voltage/current converter, QO@)---operation detector,
(107) -... Comparator, (108)... 20th differential circuit agent Yoshihiro Morimoto Figure 2 Figure 5 Part 21 ↓ 1:

Claims (1)

[Claims] L: a position detecting means for detecting the position of the movable part of the motor; 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 detecting 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 group of drive transistors; and an output of the position detection means. a second drive transistor group that distributes and controls energization of the second drive transistor group in response;
distribution control means; the second distribution control means includes operation detection means for detecting the operating voltage of the transistor in the energized state of the first drive transistor group; A Puff V-less direct current motor for controlling the operating state of the transistors in the energized state of the third drive transistor group in accordance with the output of the means.