JPS58130787A - Dc motor - Google Patents

Abstract

PURPOSE:To reduce the base current loss of a DC motor at the low current energizing time by increasing or decreasing the base current of a drive transistor in response to the detected value of the output voltage of a voltage converter. CONSTITUTION:The speed corresponding voltage Vd from a speed detector 13 is inputted to a switching controller 21, and the output voltage Vc of a voltage converter 10 becomes a value corresponding to the voltage Vd. The common emitter current of a distributor 11 which inputs the detection signal of a position detector 6 is supplied by a current supply unit 12. The unit 12 detects the voltage Vc via a resistor 27, and when the voltage Vc becomes large, the voltage across the resistor 17 becomes large, and the current of a transistor 28 and a resistor 29 becomes large. Accordingly, the collector current of a transistor 30 becomes large, is inverted by transistors 32, 33, and is supplied to a distributor 11. When the voltage Vc becomes small, the supplied current to the distributor 11 becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC motor, and more particularly to an electronic commutator type (brushless type) DC motor that efficiently utilizes electric power supplied from a power source.

Conventionally, when controlling the speed of a DC motor, for example, a transistor or other device was used to reduce and control the voltage from a DC power supply with a constant output voltage, and supply a drive voltage corresponding to the speed of the motor to the drive windings. .

In such a configuration, the power supplied by the DC power supply is the sum of the effective power consumption in the drive winding and the collector loss of the transistor. In a normal DC motor, the collector loss of the transistor is quite large, and the ratio of effective power consumption to power supply (fIl, power efficiency) is small;
It was about 1. In particular, DC motors with a wide variable speed range that can be switched in multiple stages, and DC motors for winding with a wide variable range of driving force, have significantly poor efficiency during low speed and low driving force operations.

In order to eliminate such drawbacks, the applicant has filed a patent application filed in 1983.
No. 4-17375 describes a DC motor with good gravity efficiency using a Suinochinog type voltage converter that can extract a variable output DC voltage.
The explanation is given using a type of DC motor as an example. by the way,
In such an electronic commutator type DC motor, DC/voltage is supplied to the drive winding via a drive transistor.

Each drive transistor turns off and on in response to the position of the motor's moving part (rotor). As the voltage increases, it is necessary to supply a large current to the drive winding, and the base DC of the drive transistor must be increased. On the other hand, when the speed is controlled at a predetermined speed and the state is tL (constant speed rotation control state), the output voltage of the Ichikawa converter is inversely to the load torque jJg+Ij)E
(proportional to the rotational speed of the motor), and the value upstream of the supply to the drive winding of the drive transistor is quite small compared to the time of startup and acceleration (for example, the startup special At 2A, the current is about 250 mA at constant speed city 1). Therefore, the base current required during constant speed control is significantly smaller than the base current of the drive transistor required during large current at startup. As a result, if the base direct current that enables large current conduction at startup (required to increase the starting torque) is constantly supplied to the drive transistor, when small current conduction occurs during constant speed rotation, This is undesirable as it causes significant power loss.

In the above-mentioned example, the driving transistor is constituted by two transistors that are dark/ton connected, and the absolute value of the base current value itself is made small. However, in such a configuration, the saturation voltage when turned on is vCE (sat) (Da 'J/ton) = vBE + vCE
(sat) and the normal transistor saturation voltage VCl (s
at) = ”~0.6V (through A4 [KJ:ru)j remote V
B g+0.7 V also increases, which is undesirable because the power loss in the Darlington-connected drive transistor increases.

In consideration of such points, the present invention detects the output voltage of the voltage converter, responds to the detected value, and increases or decreases the base DC current of the drive transistor (the drive transistor is turned off and off). ), it provides an electronic commutator type DC motor with low current flow and low base flow loss during electric operation.

Hereinafter, the present invention will be explained based on a large embodiment shown in the drawings.

FIG. 1 shows an upper air circuit representing a one-shot embodiment of the present invention.

In the figure, 1 is a DC power supply, 2 is a field magnet attached to the motor moving part (rotor), 3, 4.5
is a three-phase drive winding that interlinks with the magnetic flux of magnet 2, 6 is a position detector that detects the position of the motor+if moving part, 7, 8
．． 9 is a drive transistor group that switches the current path to the winding 3+'+6, and the Mlf component 1o surrounded by the broken line is a switch puffer type that is interposed between the DC power supply 1 and the drive windings 3, 4.5. 11 is a distributor that controls the +1ji current of the drive transistors 7, 8, 9 in response to the output of the position detector 6, and 12 is a current supply device that supplies direct current to the distributor 11.

Further, 13 is a speed detector which detects the rotational speed of the magnet 2 and obtains a voltage signal corresponding to the speed.Next, its operation will be explained. The rotational speed of the magnet 2 (motor moving part) is detected by the speed detector 13, and a voltage signal vd corresponding to the detected speed is input to the switching controller 21 of the voltage converter 1o. Switching controller 2
1 is constituted by, for example, a sawtooth wave oscillator and a conoparator (a variety of well-known configurations can be used), and generates a pulse signal with a duty ratio corresponding to the input voltage to control on/off of the switching transistor 22. .

Inductor element 24. Smoothed by capacitor 26 and flywheel diode 23, voltage converter 1
The output voltage vc of 0 is a value corresponding to the on-time ratio of the switching transistor 22, that is, the speed detection 613
The value corresponds to the output voltage ■d.

The position detector 6 distributes a digital voltage signal to a Hall element that senses the magnetic flux of the magnet 2 and a circuit that shapes and synthesizes its output. Each transistor 34, 36, 36 of the 4S11
is applied to the base terminal of.

The emitters of the transistors 34, 36, and 36 of the distributor 11 are commonly connected, and the transistor with the lowest base potential is activated, and the other transistors are inactive. As a result, the input current (common emitter current) of the divider 11 becomes the collector current of the active transistor, and the collector currents of the other transistors become zero. The collector currents of the transistors 34, 35, 36 of the distributor 11 each become the base current of the drive transistor 7.8.9, and control the on/off of the drive transistor 7.8.9'i.

The common emitter direct current of the distributor 11 is supplied by the current supply 12.
11 The output vehicle pressure c of the converter 10 is detected by the resistor 27, and the 1u pressure is 1 direct V. Increases the current supplied to the circuit 4211-distribution A J11 (therefore, the base current of the transistor C +1 increases), and the voltage value ■. When becomes smaller, the current supplied to the distributor 11 is reduced (
Therefore, the base current of the drive transistor becomes smaller).

In other words, as VC increases, the voltage across the resistor 27 increases, and the current flowing through the transistor 28 and the resistor 29 increases. Transistors 28, 30, and 29, 31 form a current mirror circuit, and the collector current of transistor 30 becomes large, and this current flows through transistor 32, 3.
3 and becomes the supply current to the distributor 11.

When the output voltage vc of the voltage converter 10 is small, the current from the current source 26 is mainly supplied to the distributor 11.

In this way, the output voltage VC of the voltage converter 10 is detected,
If the base current of the drive transistor is changed according to this value, sufficient base current can be supplied to the drive transistor even during high current operation during startup and acceleration, and the base current can be supplied to the drive transistor during high current operation during constant speed rotation control. The current can also be reduced, and base sleep current loss during constant speed rotation is significantly reduced.

To explain this, when the rotational speed of the magnet 2 is slow in the startup/acceleration stage, the output voltage Vd of the speed detector 13 is small, and the switching controller 21 increases the on-time ratio of the switching transistor 22. , the output voltage V of the voltage converter 10. is increased, a large current is supplied to the drive winding, and high speed torque is obtained. Now, assuming that the winding resistance is r210Ω and the maximum value of vo is 19V, the drive transistor will be activated at startup? , 8.9 is 18■/1
oΩ = t, s A current is applied (saturation pressure is 1V)
.

At this time, the DC amplification factor hFE of the drive transistor is set to 40
Then, the base IIL flow required at startup is 1.9A/
40=45mA.

Output 1L voltage of voltage converter 1o■. When is large, the current of the resistor 27 becomes large, increasing the output current of the current supply device 12, and supplying a large base current (about 50 mA) to the drive transistor selected by the position detector 6 and the distributor 111) As a result, the drive transistor draws a large current jm! The current is supplied to the corresponding drive winding, and a large acceleration torque is generated by interaction with the magnet 2.

When the magnet 2 is accelerated to a predetermined rotational speed, the output voltage vd of the speed detector 13 increases, and the switching controller 21 decreases the on-time ratio of the switch/gate transistor 22 to increase the output voltage of the voltage converter 10. V. is made small, and a constant speed rotation control state is reached. Now, if we ignore the back electromotive force as small and set V, = 3V,
The current of the drive transistor is 2.6V/10Ω=2
50 mA (saturation voltage is 0.6V). Therefore, the base current required to turn on the drive transistor is 260/40=6.25 mA, and if a base current of about 8 mA is supplied with a little margin, the drive transistor will surely turn on (saturated operation).

In other words, the base current of the drive transistor is 4 at startup.
5 mA is required, but when the constant speed rotation is controlled with light load torque, a, 2 smA is sufficient, and the difference is 38.
It may be reduced by 75mA. As a result, while the drive transistor can be turned on and off reliably, its base current loss is significantly reduced.

FIG. 2 shows an electrical circuit diagram representing another embodiment of the invention. In this embodiment, the current supply device 1 of the embodiment shown in FIG.
A transistor 4o is added to 2 to further reduce base current loss in a motor with a large back electromotive force under constant speed rotation control.

This will be explained in reference to r, J'' (2).

Figure 3 shows the drive transistor 7 in the constant speed rotation control state.
1 is a current circuit diagram of the drive line 3 when it is in transit.

When the motor rotates at a constant speed, a counter-motive force is induced in each driving coil, which acts in a direction that reduces the rli flow to the windings. As a result, the current fat supplied to the winding 3 is “= (Vc-”B-vCE(sat))/r・
−・(ri.Now, the back-lift pressure during constant speed rotation is j!:
Assuming B = 9 V, Vo = 12 V, vCE (salyu, sV, r = 10Ω, I = 250 m
8, and the base DC required for the drive transistor hNE-40 is 250 / 40 = 6.25m
A and naru. 12V is a relatively large value, but the back electromotive voltage EB generated in the drive winding is quite large at 9V, so the required base current of the drive transistor is 6V.
．． It's quite small at 25mA, which is good.

The output voltage vd of the speed detector 13 is applied to the base terminal of the transistor 4° added to the current supply device 12. The output voltage vd of the speed detector 13 has a small voltage value (approximately 2 V) in the startup/acceleration stage (low speed state), and increases in the constant speed control state at a predetermined speed (depending on the load torque). Although it fluctuates, it is usually stable at around 9cm) 0 Output voltage of voltage converter 1o and speed detector 1
The output voltage vd of 3 is compared by the transistor 4o, and if Vo is greater than Vd by 0.7V (base-emitter forward voltage drop) -F, the difference voltage (Vo-
The current value obtained by dividing Vd-0,7) by the resistance value of the resistor 27 is the current value of the transistors 28, 30 . The current is supplied to the resistors 29 and 31 and combined with the current of the constant current source 26 to become the output current of the current supply device 12.

Therefore, the base current supplied to the drive transistor is (
Vo-Vd-0,7), and during constant speed rotation control, the current flowing through the r1 drive transistor IC(
Corresponding to the reduction due to the back electromotive force EB in Equation 1), the base current is also reduced, significantly reducing base current loss.

Furthermore, large DC current during startup and acceleration 1. When the speed detection 513L7) output) h, 1: f:, V d is small and the difference 1 u pressure (VC - Vd - 0,7) can be large, the base DC supplied to the drive transistor is 1
The output voltage of the pressure transducer 10 is ■. A large value corresponding to the current value allows the drive transistor to be turned off and turned off sufficiently.

(The implementation j in Figure 2 is connected to a DC motor that is controlled to rotate 11.5 consecutive times with a large back electromotive voltage. , :t/, and the implementation row in Figure 1 is a low speed motor with a small back electromotive force. (It is suitable for a DC motor that rotates +&lI.) Fig. 4 shows a circuit diagram of a streetcar 10 representing another embodiment of the present invention. In this embodiment, - is connected to the positive terminal of the voltage converter 10.
4 (collector terminals) are commonly connected, and each output terminal (emitter terminal) is driven %1pJ a , 4 .

The first drive transistor 14°15.1 connected to 6
6 and the voltage converter 10, the - end (emitter terminal) is commonly connected to the negative terminal of the voltage converter 10, and each output terminal (collector terminal) is connected to each output terminal of the first drive transistor 14° 16.16. Two drive transistors 7.8.9 are provided, and the current path of the drive winding 3.4.6 is switched on both the positive and negative sides to constantly supply direct current to the two drive windings. Q, which improves the efficiency of line utilization.Next, its operation will be explained. The rotational speed of the magnet 2 is detected by a speed detector 13, and a voltage signal vd corresponding to the rotational speed is output. Depending on the output voltage d of the speed detector 13, the switching controller 2 of the voltage converter 10
1 controls the on-time ratio of switching transistor 220 and diode 23 . Intertact element 24. After smoothing with capacitor 25, the output voltage is ■. is under control.

The output voltage vc of the voltage converter 10 is applied to the first drive transistor 14. i5, 16 and second drive transistor 7
．． 8.9 is applied to the drive winding $31,496.

Place lr+1 dislocation 1ft of magnet 2 in position 1! Effect 1 (
Detected at 6 and digital IIJ according to the position
, pressure No. 16 (6 pipes) is input to the distributor 11. Distributor 1
1 is composed of a first differential circuit 61, a second differential circuit 62, and current mirror circuits 63, 64, 65, and the transistor/transistor 41 of the first and 20th differential circuits 61, 62.
, 42, 43, 34, 36.36, the output voltage of the position detector 6 is applied to each base terminal.

The first differential circuit 61 has a voltage of 1 depending on the base voltage of the transistors 41, 42 and 43 (the voltage applied to the output 1 of the position detection unit 6).
When transistors are activated, the common emitter current (
The output i [current] of the current supply device 12 is distributed to the collector side. The collector current flows through current mirror circuits 63, 64.
65 through the first drive transistor 14, 15, 16
The flow becomes a current of 1 [C, and one of the first drive transistors corresponding to the output of the position detector 6 is always in the OFF state.
There is.

Further, the 20th differential circuit 62 includes transistors 34°, 35.
36 base pressure (output voltage of position detector 6), one transistor becomes active, and the common emitter current (
The output current of the current supply device 12) is distributed to the collector side.

Its collector current flows through the second drive transistors 7, 8.
9, and one second drive transistor corresponding to the output of the position detector 6 is always in an off state.

The common emitter direct current of the first and second differential circuits 61 , 62 of the distributor 11 is supplied by a current supplier 12 .

The current detector 12 detects the output voltage V of the voltage converter 1°. is detected by the resistor 27, and its voltage value ■. When V increases, the current supplied to the divider 11 is increased to increase the base current to the first and second drive transistors, resulting in a voltage value V.

When the current becomes smaller, the current supplied to the distributor 11 is reduced to reduce the base current to the first and second drive transistors.

As a result, sufficient base direct current is supplied to the first and second drive transistors even during large current operation during startup and acceleration, and the base current is lower than the minimum required during small current operation during constant speed rotation control. By reducing the base EE flow to a slightly higher level, the loss of the base EE flow is significantly reduced.

FIG. 6 is a diagram showing still another embodiment of the present invention. In this embodiment, a transistor 40 is added to the current supply device 12 of the embodiment shown in FIG. 4, and the loss of base current 4ti is further reduced in a motor with a large back electromotive force in the constant speed rotation control state VC. It is. The operation of the current supply device 12 is the same as that described in the embodiment shown in FIG. 2, and the output voltage of the speed detector 13 is
Using d, ■.

By comparing Vd with
In addition, when Vd is large during constant speed rotation control, the difference (Vo - Vd) becomes small, and the output of the current supply 12 is The current (base current #r of the drive transistor) is reduced to reduce the base current loss of the drive transistor (the drive transistor operates in an off-center manner).

(The embodiment shown in Fig. 6 is suitable for a DC motor that is controlled to rotate at a high speed and has a relatively large back electromotive force generated in the drive winding. The embodiment shown in Fig. 4 is suitable for a DC motor that is controlled to rotate at a low speed and has a small back electromotive voltage. Although the above-described embodiment shows an example in which a three-phase drive winding is used, the present invention is not limited to such a case, and is generally applicable to multiple-phase drive windings. It is possible to configure a DC motor with It's a good thing, it's not limited to a star connection, it can also be a ring connection. Furthermore, a position detector 6. The speed detector 13 and the switching controller 21 can adopt various known configurations.

Moreover, the distributor 11. Current supply device 12. It is possible to form an integrated circuit (IC) on a silicon chip, including the drive transistors 7.8.9 (and 14.ts, 1e).

As is clear from the above explanation, the DC motor of the present invention is an electronic commutator type DC motor with high power efficiency. Therefore, based on the present invention, it is possible to use a dry pond as a power source for audio/visual equipment. If a DC motor is used, it is possible to realize a device that consumes less gravity and has a longer 1U battery life.

[Brief explanation of drawings]

Figure 1 shows Kazushu J! of the present invention! Fig. 2 is an electric circuit diagram for explaining the effect of another embodiment of the present invention, Fig. 3 is a circuit diagram for explaining its effect, Figures 1 and 5 are electrical circuit diagrams representing other embodiments of the present invention. 1... DC power supply, 2... Magneto 7),
3゜4.6... Drive winding, 6... Position detector, 7゜8.9... Drive transistor 7 transistor (switch or second drive transistor) ), 1o------heavy pressure converter, 11------distributor, 12------1
[Flow supply device, 13... Speed detector, 14, 15.
16...--First drive tractor 7 register, 21...
... Suinonanog City 11 〇 Agent's name Patent Attorney Toshio Nakao and 1 other person Figure 2/3 i 3rd f! 1

Claims (2)

[Claims] (1) position detection means for detecting the position of the motor movable part;
a plurality of phase drive windings, a drive transistor group for switching current paths to the drive windings, a distribution means for controlling energization of the drive transistor group in response to an output of the position detection means, and a DC power supply; A switching type voltage conversion means for obtaining a variable output DC voltage from the DC power supply, and a current supply means for supplying current to the distribution means, the current supply means detecting the output voltage of the voltage conversion means. and changes the current supplied to the distribution means in response to the output voltage, increasing the base current of the drive transistor when the output voltage increases, and decreasing the base current of the drive transistor when the output voltage decreases. A direct current motor characterized by being configured to be small. (2) position detection means for detecting the position of the motor movable part;
A plurality of phase drive windings, a DC power supply, a switching type voltage conversion means for obtaining a variable output DC voltage from the DC power supply, one end of which is commonly connected to the positive terminal of the voltage conversion means, and each output terminal is connected to the positive terminal of the voltage conversion means. has one end commonly connected to a first drive transistor group connected to the drive winding and a negative terminal of the voltage conversion means, and each output terminal is connected to each output terminal of the first drive transistor. a second drive transogistor group;
and a distribution means for controlling the conduction Elj of the second drive transistor group, and a current supply means for supplying direct current to the distribution stage (1i! detecting the output voltage of the means, and changing the direct current of the front dpi dividing stage -\ in response to the output voltage, and when the output voltage becomes large, the base currents of the first and second drive transistors are changed; □The direct drive transistor is configured such that when the output voltage increases, the base currents of the first and second drive transistors decrease as the output voltage decreases.