JPS5852439B2 - Rotating body rotation speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The first object of the present invention is to provide a rotational speed of a rotating body that has little change in rotational speed in response to fluctuations in supply voltage and that can be adjusted or varied extremely efficiently. The purpose is to obtain a control device.

A second object of the present invention is to obtain a rotational speed control device for a rotating body in which the rotational speed is less subject to environmental changes and changes over time.

Conventionally, methods for controlling the rotational speed of a rotating body at a constant level using the output signal of an alternating current generator called a tachogenerator, which is built in or connected to the rotating body, can be roughly divided into voltage control method and frequency control method. It is well known that there are two methods, but while the former can be realized with a simple circuit configuration, it is susceptible to environmental changes in rotational speed and changes over time, and the latter has a circuit configuration that does not have these drawbacks. It is a well-known fact that this can become complicated.

FIG. 1 shows an example of a DC motor rotational speed control circuit using a voltage control method, which has been widely used in the past, and the problems thereof will be described below.

In FIG. 1, one end of an alternator 9 that is built in or connected to a DC motor 10 and generates an AC signal whose frequency changes depending on the rotational speed of the DC motor 10 is connected to a negative power supply line, The other end is connected to the base of a switching transistor 2 via a resistor 1.

The emitter of the switching transistor 2 is connected to a negative power supply line, and a resistor 3 is connected between the base of the switching transistor 2 and the negative power supply line.

The collector of the switching transistor 2 is connected to a positive power supply line via a resistor 4, and a capacitor 5 is connected between the collector of the switching transistor 2 and the negative power supply line.

Furthermore, the base of a transistor 6 is connected to the collector of the switching transistor 2, and the collector of the transistor 6 is connected to a positive power supply line via a resistor 7.

Further, the emitter of the transistor 6 is connected to the transistor 8.
The emitter of the transistor 8 is directly connected to the negative power supply line, the collector is connected to one terminal of the DC motor 10, and the other terminal of the DC motor 10 is connected to the positive power supply line. has been done.

The rotation speed control device for a DC motor shown in FIG. 4 and a capacitor 5, the DC voltage is converted into a DC voltage dependent on the rotational speed of the DC motor 10, and this DC voltage operates a drive circuit consisting of transistors 6 and 8 to keep the rotational speed of the DC motor 10 constant. It is something to control.

Now, in FIG. 1, the rotational speed of the DC motor 10 is controlled so that the smoothed voltage EI of the switching output waveform and the sum of the base-emitter forward voltages of the transistors 6 and 8 (EBE6 +EBE8) are equal.

In Fig. 1, the generated voltage of the alternator 9 is Eg(■T
)-1)), the output signal cycle is Kf (c/rev), the internal resistance of the power generation winding is RG, and the resistance values of resistors 1 and 3 are R1 and R3, respectively, when the base current does not flow. Base voltage EB of transistor 2 is given by the following equation.

However, N (rpm) is the rotation speed of the motor.

When the base voltage EB of transistor 2 exceeds the base-emitter forward voltage EBE2, transistors 1 to 2 become conductive, and if that time is tl, then the width FT of the cutoff section of transistor 2 is as follows. It becomes like this.

However, on the other hand, when the power supply voltage is Es, the smoothed voltage EI is as follows.

-KfNTFo5R4(6) EHfoEs(1g)dt 0 In equation (6), C5 is the capacitance of capacitor 5, and R
4 is the resistance value of resistor 4.

Here, in order to make the relationship between E■ and N easier to understand, equation (6) is expressed by the following approximate equation.

, KfN T t E■--fo Es dt (7) 60
C, R4 When formula (7) is calculated in consideration of formula (4), where: If the formula (7) is calculated, then the formula (8) becomes as follows.

In equation (10), a/Eg takes a value from 0 to 1, so that sin''-1Ca/E, ) is from O to π
/2.

When a/E takes a value near 0, a/E
5in-1Ca/Eg) also changes linearly with respect to the change in g, but when a/Eg takes a value near 1, sin''-I with respect to the change in a/E
The change in Ca/E, ) becomes very large.

That is, as a/Eg approaches 1, the rotation speed-DC voltage conversion gain becomes larger, but it is more influenced by the fluctuation component of the detected voltage, and the control form becomes closer to a pure voltage control method.

Now, the power generation constant of the DC motor 10 is Ka, and the gain of the DC amplifier section formed by the transistors 6 and 8 is the smoothed voltage EI.
If the overall gain considering the ripple content of is A, then
In a normal feedback loop, when the reference voltage ER and the feedback voltage βN are given, the rotational speed N of the DC motor 10 is as follows.If the reference voltage E□ increases, N increases in proportion to it, and the feedback voltage βN It changes in proportion to N.

However, in the circuit shown in Fig. 1, if the sum of the base-emitter voltages of transistors 6 and 8 is regarded as the reference voltage, and EI given by equation (10) is regarded as the feedback voltage, the actual operation and the theoretical The above phenomenon is reversed.

That is, if we consider the actual operation, as is clear from equation 00), the feedback voltage E is inversely proportional to N, and as the base-emitter voltages of transistors 6 and 8 increase, the feedback voltage E Since the feedback loop operates to increase the rotation speed of the motor 10, the rotation speed of the motor 10 becomes low.

In order to eliminate these unreasonableness, here, for convenience, the reciprocal 1/ER is given instead of the reference voltage, and the reciprocal 1/βN is given instead of the feedback voltage 1yN (EI).

In addition, a special unit function called Eu2 is used to resolve the dimension mismatch caused by these operations.

In the circuit of Figure 1, the base of transistor 6.8
If the emitter voltage is EBE6°EBBs, then 1/ER is equal to (EBE6+EBE8),
Since 1/βN is equal to 1/E■, considering the equation 00), the rotational speed N of the DC motor 10 is controlled to the following value.

In one set, E% is a unit function with a dimension of the square of the voltage, E2=1 (V2) (1
2) By the way, the overall gain A of the drive section is expressed by the following equation, where r (support) is the ripple content and Ao is the DC gain due to transistors 6 and 8.

by the way, Looking at the complete set, the power supply voltage Es changes. It can be seen that the rotation speed N also changes.

In other words, as Es increases, the rotational speed N increases, and E8
As the number of rotations N decreases, the number of revolutions N decreases.

In order to avoid this inconvenience, conventional devices of this type stabilize the voltage between the feed lines, or as shown in Figure 2,
Capacitor 5 is connected by resistor 12 and voltage regulator diode 11.
Methods have been taken to stabilize the charging voltage.

Now, in Fig. 2, the variable resistor 13 inserted between the alternating current generator 9 and the base of the switching transistor 2 is used to adjust or vary the rotational speed N of the DC motor 10 by changing a of the 00 type. It is.

However, such a rotational speed adjustment method causes the following disadvantages.

That is, first of all, as is clear from the α9 formula,
The number of rotations N does not change linearly with respect to a change in a, and when it is desired to change the number of rotations N significantly, the linearity of the change in the number of rotations N with respect to a change in a deteriorates significantly.

Furthermore, when it is desired to significantly change the rotation speed N, or when the output voltage of the alternator 9 has large variations, it is necessary to considerably increase the amount of attenuation by the resistors 1 and 3 and the variable resistor 13. As the amount increases, the output voltage of the alternator 9 also increases, which not only increases the harmful noise from the generator section, but also increases the loss in the generator section, resulting in a decrease in efficiency.

The next problem is that from equations (8) to αυ, unless a/Eg is 0, that is, the output voltage of the alternator 9 is much larger than the base-emitter forward voltage EBE2 of the transistor 2. , the output voltage E3 of the alternator 9
Changes in the number of revolutions N, that is, the rotational speed of the motor, affect the motor's rotational speed, and it is impossible to consider the morph part and the control circuit part completely separately as in a pure frequency control system.

The rotational speed control device for a rotating body according to the present invention solves the above-mentioned problems.

FIG. 3 shows an example of a rotational speed control device for a rotating body according to an embodiment of the present invention.

Items in Figure 3 whose functions and configurations are exactly the same as those shown in Figures 1 and 2 are designated by the same figure numbers as in Figures 1 and 2, and explanations of their configurations and operations are omitted. do.

In Figure 3, a voltage stabilizing transistor 1 is shown between the feed lines.
A series circuit of a resistor 12 is connected between the collector and emitter of the resistor 4.

Further, a speed adjusting variable resistor 15 is included between the collector and base and between the base and emitter of the transistor 14, and a resistance voltage dividing circuit consisting of resistors 16 and 17 is connected.

Further, power is supplied to the collector of the switching transistor 2 from the collector of the transistor 14 via a resistor 4, and an alternating current generator 9 is connected between the base of the transistor 2 and the base of the transistor 14.

Incidentally, the variable resistor 15 is used as DC and rotation speed setting means for the motor 10.

Now, in FIG. 3, the transistor 14, the resistor 12,
16, 17, and a variable resistor 15 constitute a well-known constant voltage circuit, and the forward voltage between the base and emitter of the transistor 14 is set to EE E 4, and the total resistance of the resistor connected between the base and emitter of the transistor 14 is The resistance value is R17, and the total resistance value of the resistors connected between the collector and base is R.
16, the collector-emitter voltage EcE4 of the transistor 14 is maintained at the following value.

16 EOB4”” EBB4 (1+-)
α → 17 By the way, the base of this voltage stabilizing transistor 14
Since the emitter is always forward biased, the signal voltage applied between the base and emitter of the switching transistor 2 is the sum of the output signal voltage of the alternator 9 and the base-emitter forward voltage EBB4 of the transistor 14. Become something.

Therefore, the base voltage EB of transistor 2 when no base current flows is: 2πKfN EB=E 5in(t) +EBE4 (J5
)3 60 E12 Cow E B E When 4 is established, the conduction time t1 of 2 becomes O.

Therefore, the cutoff section width TF of transistor 2 It becomes like this.

0 TF= fN When formula (7) and formula 6) are calculated, the transistor is as follows (16) Therefore, the rotation speed N of DC motor 0 is controlled to the following value.

N=08)(””
+ ””””’t (EBE6+EBE8)E2
A 7.5ES By the way, in equation (11g), Es is the supply voltage, more specifically, the power supply voltage supplied to the smoothing circuit,
In the circuit shown in Figure 3, from equation 04), 16 Es = E C3 and 4 = EBB4 (1+-)
(II17) Therefore, Es in the arbitrary formula is unrelated to fluctuations in the power supply voltage, and changes only when the variable resistor 15 is adjusted to change the ratio of R16/R1□.

In other words, (IL) As can be seen from equation (19), the charging voltage E8 of the capacitor 5 is not affected by fluctuations in the power supply voltage, so the rotational speed of the DC motor 0 is kept extremely stable against fluctuations in the power supply voltage. be able to.

Furthermore, by adjusting the variable resistor 15, Es can be changed, as can be seen from equation 00 or equation (2), and the rotational speed of the DC motor 0 can be adjusted.

Furthermore, as is clear from the α Azuma formula, the rotational speed N of the DC motor 0 in FIG. 3 is not affected by the output voltage E2 of the AC generator 9.

The rotational speed adjustment method of the present invention does not attenuate the output voltage of the AC generator 9 unlike the conventional attenuation method shown in FIG. The rotational speed can be varied or adjusted very efficiently without causing any problems.

In the embodiments of the present invention, a rotational speed control device for a DC motor has been described, but the present invention is applicable not only to a DC motor but also to a rotational speed control device for any rotating body including other motors and gasoline engines. It is possible.

As described above, according to the rotational speed control device for a rotating body of the present invention, a voltage stabilizing transistor is provided, the stabilizing voltage is changed by a variable resistor inserted in the base circuit of the transistor, and a switching transistor Since an alternator is inserted between the base of the voltage stabilizing transistor and the base of the voltage stabilizing transistor, the output of the alternator can be attenuated by a voltage dividing circuit to vary the rotational speed of a rotating body. , it is possible to realize a device that can efficiently vary and adjust the rotation speed without deteriorating the utilization efficiency of the generated output of the alternator, and it is possible to realize a device that can efficiently vary and adjust the rotation speed without deteriorating the utilization efficiency of the generated output of the alternator. The frequency control method is easy to implement, uses fewer parts than conventional frequency control methods, is highly reliable, and can perform highly accurate speed control, providing extremely superior effects.

[Brief explanation of the drawing]

1 and 2 are circuit connection diagrams of a conventional DC motor rotation speed control device, respectively, and FIG. 3 is a circuit connection diagram of a DC motor rotation speed control device according to an embodiment of the present invention. 2...Switching transistor, 9...
...AC generator, 10...DC motor, 11.
... Constant voltage diode, 13 ... Variable resistor, 14 ... Voltage stabilizing transistor, 1
5...Variable resistor.

Claims (1)

[Claims] 1: an alternating current generator that is built in or connected to a rotating body and generates an alternating current signal whose frequency changes according to the rotational speed of the rotating body; a switching transistor that performs a switching operation based on the output signal of the alternator; and the switching transistor. In a device equipped with a smoothing circuit that smoothes a switching signal appearing on the output side of the power supply line and converts it into a DC signal, and a drive circuit that controls the rotational speed of the rotating body using the output voltage of the smoothing circuit, the voltage is stabilized between the power supply lines. A series circuit of a resistor is connected between the collector and emitter of the voltage stabilizing transistor, a resistive voltage divider circuit including a variable resistor is connected between the collector and base and between the base and emitter of the voltage stabilizing transistor, and Power is supplied to the collector of the voltage stabilizing transistor via a resistor, and the variable resistor serves as means for setting the rotational speed of the rotating body, and the base of the switching transistor and the voltage stabilizing transistor are connected to each other. A rotational speed control device for a rotating body, characterized in that the alternator is connected between the base of the rotating body and the base of the alternator.