JPS5899280A - Dc motor wherein synchronous control is performed - Google Patents

Abstract

PURPOSE:To perform the synchronous control, by controlling an armature current so that the phases of a synchronizing signal and a rotary position detecting signal of the DC motor are discriminated, and a converted DC voltage agrees with the product of the detected counter electromotive force of the motor and an armature current. CONSTITUTION:A bridge circuit comprising resistors 3-5 and the motor 2 is constituted between a positive voltage terminal 1 of a power source 1 and a ground. A transistor (TR) 11 is connected to an armature circuit in series. A specified current flows into a base, and a constant current circuit is constituted. When the voltage at a terminal 31a is increased, a Schmitt trigger circuit 31 makes the TR11 nonconductive. When said voltage is decreased, the TR11 is conducted. Thus the armature current repeats the increase and decrease together with a flywheel diode 2a, with the normal repeating frequency being about 20kHz. The output of a position detector 10c of the motor and the output of a synchronous signal generator 10b are imparted to a phase discriminator 10, and the converted DC voltage is imparted to a differential amplifier 8. Control is performed so that the product of the detected electromotive force and the detected value of the armature current becomes equal to the DC voltage. Thus the synchronous control of the motor 2 can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronous control device for a DC motor. Such technology is particularly needed when used as a motor for driving a capstan in a magnetic recording/playback machine.

Nowadays, the standard speed fluctuation rate is about 0.03%, and the control characteristics of constant speed control devices are particularly problematic.

The most widely used bridge servo circuit, due to its simplicity, is the well-known bridge servo circuit, but it has major drawbacks. First, the warm dependence of rotational speed and load characteristics are poor. There is generally a 2-3- change in rotational speed. Second, since each revolution includes 6 to 12 pulses of pull torque, it is technically impossible to reduce wow and flutter to less than the above-mentioned value.

For the above reasons, a frequency generator is provided and an F--■ conversion circuit is used to control the armature current to perform constant speed control. In this case, the temperature characteristics and load characteristics are greatly improved. However, such means increase the output frequency of the frequency generator for constant shore control and include a circuit to eliminate speed fluctuations due to ripple torque, making the control device complicated and expensive, and making it difficult to produce on-site. Sometimes, the adjustment is delicate and becomes a problem that disrupts the flow of mass production.

From the above points of view, the capstan-driven electric motor with the best performance is an electric motor whose rotational speed is controlled by synchronous control (PLL control) with good temperature and load characteristics, and which also eliminates ripple torque and has smooth rotation. This is the result.

The novel technology of the present invention satisfies the above-mentioned demands.

Since the ripple torque is demonstrated, there is no need to set the frequency of the position detection electric signal high, and therefore a simple position detection device is required. It has the characteristic that synchronous control can be performed using a position detection electric signal that utilizes changes in armature current at the position.

Furthermore, the inductance of the armature coil is used to control the rotational speed without Joule loss.

Next, the details of the embodiments shown in FIG. 1 and below will be explained.

The idea of the present invention can be applied to any of the well-known semiconductor motors or commutator motors equipped with two-phase or three-phase armature coils, but as will be described later, it is applicable to DC motors with three-phase armature coils. If applied to what is called a Y-type connection in an electric motor, the effect will be even greater.

In FIG. 1, a bridge circuit consisting of resistors 3, 4, 5 and a motor 2 is constructed between the power supply positive voltage terminal l and the ground. Further, the electric motor 2 is an electric motor consisting of an armature, a commutator, and a brush connected in Ylli or delta type. Each resistance value is adjusted so that the voltages at the terminals ASB are equal when the motor 2 is stopped. Therefore, when the electric motor 2 rotates, a voltage proportional to the rotational speed is obtained between terminals A and B, and this voltage is applied to the differential amplifier circuit 6.
The width is increased by The voltage between terminals A and B is shown as curve 27 in the graph of FIG. 4 and includes a ripple voltage. However, the curves 27a and 27b are different as will be described later. This ripple voltage corresponds to the strength of the magnetic field. In the case of what is commonly called a three-pole motor with a Y-type connection, two armature coils are always connected in series, so the induced output of each armature coil is the sum. The horizontal axis of the graph in Figure 4 is time, and the vertical axis is voltage.

The transistor 11 is connected in series to the armature circuit, and a predetermined current flows into the transistor 11 from the pace terminal 11a to obtain an almost constant pace current, thereby forming a constant current circuit. Transistor 11 is therefore operating in the active region. In the case of constant speed control, the pace current described above is selected so that the armature current corresponds to the rotational speed and load.

For example, in the case of a three-pole motor with a Y-type connection and a magnetic field width of 180 degrees, the commutator is short-circuited by the brush six times per revolution. At this time, since the impedance of the armature decreases, the voltage drop between the collector and emitter of the transistor 11 increases in order to maintain a constant current. This time span is extremely short. Such voltage pulse is the portion shown as symbol 27a in the graph of FIG. The graph in Figure 4 shows A in Figure 1,
The counter electromotive force at point B was described above, but when curves 27a and 27b shown in the graph of FIG. 4 are added, the voltage waveform at point E on the collector side of transistor 11 in FIG. 1 is shown. . In the case of three-phase Y-type wiring, two armature coils are short-circuited by the brush as described above, and then when one armature coil is separated from the brush, the other armature coil is energized. The current will increase. However, due to the inductance, when viewed from the transistor 11 side, the impedance becomes significant and may even temporarily increase, so the voltage drop between the emitter and collector of the transistor 11 operating in the active region rapidly decreases. to 1
Decreases over time. Therefore, the voltage at point E temporarily rises rapidly, and an electric pulse 27b (FIG. 4) is generated. The number of such electric pulses is equal to the number of commutator pieces, and the position sensing electric pulses are obtained every rotation. This electrical pulse is
The signal is inputted to an electric circuit 10 via a bypass filter 9 .

The electric circuit including the electric circuit is a well-known PLL circuit (face-locked loop circuit), which uses a synchronizing signal (generally the output of a separate oscillation circuit, the output of a crystal oscillator, or the frequency of a commercial AC power source). ) generating device 1
A synchronization signal is input from 0b. Electric circuit 1
0 is called a phase discrimination circuit, and as shown in FIG. 9.10, the output of the detailed code generation circuit 10b is inputted as a rectangular wave pulse as a position detection electric signal (this details hV (details will be described later)). Since this is input to the flip-flop circuit 43, its output becomes a rectangular wave pulse of a certain pitch, and together with the input to the terminal 41, the phase discrimination circuit 4
4 is entered.

Time chart (a) in FIG. 1O shows the input to the terminal 41, and time chart (b) shows the input to the terminal 44-a. When the rotational speed of the electric motor is smaller than the synchronous speed, the pulse width of the position detection electric signal becomes smaller, as shown by symbols 50a and 50b in the figure (b), and the trailing edge of the synchronous signals 49a and 49b and the position detection The difference between the electrical signals 50 a and 50 b and the trailing edge increases with time, and becomes K as shown in the electrical signals 51 m and 51 b in the diagram (C). Such an output is obtained from terminal 44b in FIG. 9, and semiconductor switch 45a is closed to charge capacitor 46 for a time proportional to the input pulse width.

When the rotational speed of the electric motor increases beyond the synchronous speed, the position detection electric signal changes to the symbol 50c50 in FIG. 10 ('0).
As shown in d, the pulse width increases. Synchronization signal 49
c, 49. the trailing edge of d, and the position detection electric signal 5Uc,
The difference from the trailing edge of 50d increases with time, and (d
) The electric signals 51C and 51d shown in the figure are as shown in FIG. Such an output is obtained at terminal 44e in FIG. 9 and closes semiconductor switch 45b, discharging capacitor 46 for a time proportional to the input pulse width.

As understood from the above control, the voltage of the capacitor 46 becomes as shown by the curve 52 in FIG. 10(a).

When the armature current corresponding to the curve 52 is applied, when the rotation speed decreases from the synchronous speed, the voltage of the capacitor 46 increases and the armature current increases, and when it increases, the armature current decreases. , synchronous operation is performed with the position detection electric signal slightly delayed in phase from the synchronization signal, and the song I! The height of 52 is maintained at a height corresponding to the load.

Further, the curve 52 is characterized by being a flat straight line when the load is constant. As will be described later, the flat straight line is an essential condition for a control circuit that removes ripple torque.

In addition to this embodiment, other means may be used as long as the PLL circuit has such an output. Since the above-mentioned control cannot be carried out at the time of start-up that is significantly different from the synchronous speed, an additional circuit is required.

An example of this will be explained with reference to FIG.

In FIG. 11, the input to the terminal 41a is the same as the input to the terminal 41 in FIG. The signals are input to the reversible counting circuit 54 and added. The input to the terminal 42a is the same as the terminal input in FIG. 9, and is a position detection electric signal. This electrical signal is input to a reversible counting circuit 54 and subtracted from it. In the time chart of FIG. 12, (a) is the output pulse of the differentiating circuit 53, and (b) is the input pulse of the terminal 42m. During synchronous operation, the above electric pulses are alternately input to the counting circuit 54, so that the zero terminal 54 e and the +1 terminal 54
Outputs are obtained alternately between the zero terminal 54c and the one-1 terminal 54d. At the time of startup, the position detection electric signal is sent to the electric nozzle 58a158 in Fig. 12 Φ).
As shown in b..., electrical pulses 57a, 57b, etc. due to the synchronizing signal are input continuously. The counting circuit 54 is designed to overflow at +2 or Vi-2 or more, so the +4 terminal 54
When an output is obtained from a, the flip-flop circuit 55 is inverted and a negative output is obtained from the terminal 551L. The output of terminal 55a is inputted to terminal 47a of FIG. 9 and makes transistor 47 conductive, so that capacitor 46 is charged to the highest voltage.

Therefore, the armature current also becomes maximum when starting. - When the synchronous speed is exceeded, as shown in FIG. 12(C), the interval between the position detection electric pulses 59a, 59b... smaller than the interval. Therefore, Denki no Kurusu 57a, 57b.
Continuously between..., Denki no Kurusu 59a, 59
A phenomenon involving b... occurs over time.

At this time, the count value of the counting circuit returns to zero, so its output returns the flip-flop circuit 5, the output of the terminal 55a rotates normally, and the transistor 47 (FIG. 9)
becomes non-conducting. At this time, since the electric motor is near the synchronous speed, the above-mentioned synchronous operation can be started. Although the flip-flop circuit 56 is not necessarily required, since two or more of the following detection electric notes are input, the counting circuit word is subtracted to become the count value Fi-2, and the output from the terminal 54e causes the flip-flop circuit to Terminal 56 of circuit 56 &
A more negative output is obtained. This output is Miko 4 in Figure 9.
Since the voltage is input to transistor 8a and conducts the transistor 46, the capacitor 46 is discharged. The armature current therefore disappears and is decelerated.

When the rotational speed falls slightly below the synchronous speed, two synchronous signals are input successively between the position detection electric pulses. Therefore, the count value of the counting circuit 460 returns to zero,
Therefore, the floating circuit 56Fi returns to its normal state, and the output of the terminal 55m rotates in the normal direction, rendering the transistor hammer non-conductive. After that, normal synchronous operation will occur.

The means shown in FIG. 11 can also be implemented by other known means.

Returning to FIG. 1, the output of the electric circuit 10 (phase discrimination circuit) is input to the X terminal 7a of the division circuit 7. Further, the output of the differential amplification circuit 6 is input to the X terminal of the division circuit 7.

Symbol 8 is an operational amplifier that amplifies the output of the divider circuit 7,
The pace current of transistor 11 is controlled. The relationship between the armature coil and commutator brushes of the motor 1 is shown in FIG. That is, armature coils 21 a and 21 b
, 21c serve as a common terminal, and the other ends are commutator pieces 20a and 20b, respectively.

Connected to 20c. There are two magnetic field poles, N and S, and the opening angle of each magnetic pole is 180 degrees, but they are not shown. The opening angle of the brushes 22a, 22b is 180 degrees.

When the armature rotates, two of each armature coil are connected in series and supplied with power from the terminal 1a, with one serving as an idle coil. Also, the angle of energization is 1 iFi 120 degrees. Therefore, the back electromotive force E generated between the brushes 22a and 22b is E=K IN (H1+H! '+HII)...
......(1). However, 1 is a constant,
N is the rotation speed.

Also, armature coil 21a1 for each of H1, Hr, and Hati.
It represents the strength of the field magnetic field in the energized sections 21b and 21c.

The generated output torque T is expressed as follows, and I (H+ +Hg +Ha) K2 is a constant -= (2). Therefore, equation (1) is modified to become E=Kt NT/I K* =Km NT/I
K8 is a constant (3). In other words, the product of output torque and rotational speed is back electromotive force E
is proportional to. The output E1 of the differential amplification circuit 6 in FIG. 1, ie, the input of the division circuit 7, is the queen back electromotive force E.

If the input voltage of terminal 7a is V, its output is V0/
Therefore, the collector current of the transistor 11, that is, the armature coil of the motor 1 is changed to Vo/E by the operational amplifier 8.
It will be proportional to. The current flowing through resistor 4.5 is so small that it can be ignored. The armature current ■ is applied so as to satisfy the following relational expression.

I=Vo/E ・・・・・・・・・・・・(3-1”)
Also, by substituting equation (3), I=V0I/8. NT ff1Jchi V0= 8NT
...Song/song (4). This equation shows that the product of rotational speed and output torque is constant. On the other hand, it also shows that if the rotational speed is constant, the output torque is also constant. However, as can be seen from equation 3-1), the product of E and 1 is 1 constant, so the output torque T is 1 constant,
Ripple torque is removed, which has the effect of

As shown in equation (4), the input voltage V at the X terminal of the division circuit 7. corresponds to the output torque of the electric motor 2. Also voltage V. is the output of the electric circuit 10, which is the curve 52 in FIG. 10(e). If this curve is not flat, as can be seen from the above theory, ripple torque will be generated, making it impossible to achieve the object of the present invention.

The input voltage Vo at the X terminal of the divider circuit 7 causes an armature current having a value corresponding to the load to flow through the transistor 11. When the load becomes small and exceeds the synchronous speed, the 10th
Electric pulses 51 c and 51 d in figure (c) are generated,
By discharging the capacitor 46 in FIG. 9, the curve 52 in FIG.
Since the height of is reduced, the input voltage at the X terminal of the divider 1 circuit 7 in FIG. Reduce the current to reduce the armature current.

Therefore, it returns to synchronous operation. When the load increases and the rotational speed decreases below the synchronous speed, the above-mentioned phenomenon is reversed and the electrical pulse 51 a of FIG. 10(b) occurs.

51b... occurs, the armature current is increased and the synchronous speed is returned to.

Synchronous operation is performed as described above, so it's full! It is characterized by good f4I properties and load characteristics.

If the electric motor 1 is a coreless type and is driven by Fleming's force (electrodynamic torque), equation (4) is directly applied.

However, in the case of a three-pole motor with a core, for example,
There will be a slight pull torque left due to the twisting, but this does not pose a problem in practice. It is clear that the same theory also applies to semiconductor motors. Not applicable to either 2-phase or 3-phase type. The reason for this is as follows.

As described above in FIG. 3, in the case of the Y-type connection, the back electromotive forces of the armature coils 21a, 21b, 21c are added together and taken out from the brushes 22a, 22b. . In addition, the output torque of each force coil is also added to form the composite output torque, so the above-mentioned back electromotive force addition method and composite torque addition method correspond to each other, which is why equation (4) holds true. It becomes. In the case of the Δ type connection, two coils are in a series circuit and one coil is in a parallel circuit, so the above-mentioned back electromotive force is added between the brushes and is not output. - Therefore exactly (4)
It cannot be expressed by a formula. However, it holds true approximately, so
Practically speaking, it can be used depending on the purpose.

In the above-mentioned synchronous operation control, when the rotational speed fluctuates, the back electromotive force also fluctuates slightly, but the increase or decrease in the back electromotive force due to this fluctuation is not a problem because it increases or decreases in the direction of stabilizing the synchronous control described above. be. In addition, the resistor 33 in Figure 1
has the following effect. At startup,
Generally, the transistor 11 is made in the saturation region 2, but in this case, the electric pulse 27b explained in FIG. 4 cannot be obtained. Therefore, as shown in the resistor shown in FIG. 1, the pace current of the transistor 11 is limited even during start-up, and the transistor 11 is operated in the active region. A means for obtaining a position sensing electric pulse that is not based on the above-mentioned means is
10c, the details of which will be described later.

As can be understood from the above explanation, the ripple torque is removed by the back electromotive force, so there is no need to extremely increase the frequency of the h-phase signal to remove the ripple torque. 6~ per revolution! Even at a frequency of 2 pulses, the rotational fluctuation of the motor 2 is slight, and when used as a capstan motor, the wow and flutter number is 0.0.
3% or less. This has the effect of eliminating the need for a high-frequency generator that is expensive and difficult to adjust.

In the case of a semiconductor motor, the present invention can be applied because electric pulses of exactly the same frequency can be obtained by the output of a Hall element serving as a position detection element. That is, by providing a device that shapes the output of each Hall element into a rectangular wave and then obtains a differential pulse using a differentiating circuit, an electric pulse train with a frequency proportional to the rotational speed can be obtained, which can be used as an input to the electric circuit 100. A simple low frequency shaft encoder can also be used as a position sensing device.

Next, another embodiment will be explained with reference to FIG.

In FIG. 2, parts with the same symbols as those in the previous embodiment are the same members and their functions are the same, so a description thereof will be omitted.

Transistors 12.12a, 12b, . . . are transistors of identical characteristics operated in the active region. Armature resistance is 1, resistance 3a is 115.

It has become. Therefore, when motor 2 is stopped,
Since a current five times as large as the current flowing through the resistor 3a flows through the armature, the voltages at point A18 become equal. When the electric motor 2 rotates, the voltage at point 1 and A decreases in proportion to its rotational speed due to its back electromotive force. This voltage drop is
The signal is amplified by a differential amplification circuit 6, and its output is input to a multiplier circuit 4.

The input of the XXY terminal of the multiplier circuit 4 is a value proportional to the output (H1+H, 10Hs) of the differential amplification circuit 6 (in the case of constant speed variation)
and is proportional to the armature current I. Input cover for Y terminal of multiplier circuit 4, transistor 12.12a, ・
Since it is common to the pace input of ..., it is proportional to the armature coil. Therefore, the output of the multiplier circuit 4 is proportional to I (H1+H, 10H8), that is, proportional to the output torque. Therefore, similar to the previous embodiment, synchronous operation can be performed via the electric circuit 10 and the operational amplifier 8. The electric circuit 10c is a position detection device, and a position detection electric signal is input from the electric circuit 10c to the electric circuit 10, which is a 9-phase discrimination circuit.

When the load is 1 and synchronous operation is performed, the output of the electric circuit IO is 1 constant value. Therefore op amp 8
through transistor 12.12m so that the output of multiplier circuit 4 is constant.

The base current of 12b... is regulated.

That is, when the output of the multiplier circuit 4 increases when the magnetic fields H11H2 and H8 are large, the output voltage of the operational amplifier 8 decreases, the armature current decreases, and therefore the input voltage at the Y terminal of the multiplier circuit 29 decreases. A negative feedback circuit is constructed in which the output is reduced to a value corresponding to the output of the electric circuit 10 without including the output torque or the pull torque.

The armature current is controlled so that the output of the multiplier circuit 4 is always kept at one constant value (the value corresponding to the output voltage of the input terminal of the operational amplifier 8, which is the output voltage of the electric circuit 10). . This fact is I (H1+H, 10H8・)=T
Since this is a control in which is constant, ripple torque is effectively eliminated. When the load increases and the rotational speed decreases, the output of the electric circuit 10 increases, and the input voltage at the ten terminals of the operational amplifier 8 increases, so the output increases, increasing the armature current and increasing the output. Torque corresponds to the load and synchronous speed is maintained. If the load decreases,
The effect is that the opposite control is carried out and the synchronous speed is maintained.

In the embodiment shown in Fig. 1.2, the Joule loss caused by the transistor 11 is used as a means of controlling the armature current, but instead, the inductance of the armature coil of the motor 2 is used to reduce the Joule loss. You can force it. An example of this is shown in FIG.

In FIG. 6, parts with the same symbols as those in the previous embodiment are the same members, so their explanations will be omitted.

Symbol 31 is a Schmitt trigger circuit in which when the input voltage at terminal 31a rises above the input voltage at terminal 31b, its output rises rapidly and becomes a no-repel, making transistor 11 non-conducting and vice versa. Then, its output becomes a low level, making the transistor 11 conductive in the saturation region. The Schmitt trigger circuit has a hysteresis characteristic in which there is a slight difference in the input voltage of the terminal 31a that makes the transistor 11 conductive and non-conductive. In the case where there is a constant load, the input of the Y terminal of the division circuit 7, which is the output of the electric circuit 10, takes a value corresponding to the above-mentioned load, and synchronous operation is performed. In this case, if the transistor 11 is conducting in the saturation region, the armature current increases and the curve becomes curve 3 in the graph of FIG.
It will be like 9.

In the graph of Figure 8, the ζ axis is time, and the vertical axis is armature current. When the armature current increases to the dotted line 37 in the graph, the input voltage at the terminal 31a in FIG. 6 also rises, causing the output of the Schmitt trigger circuit 31 to go high, so that the transistor IIU becomes non-conducting. The electrical energy stored in the inductance of the armature coil is discharged by the flywheel diode 2a, and the armature current decreases. This curve is shown by the curve chrysanthemum in the graph of FIG. Therefore, the voltage at the terminal 31a drops to the point indicated by the dotted line, and the output of the Schmitt trigger circuit 31 changes to a low level, making the transistor 11 conductive. In this way, the cycle is completed.

The above pull current is the Ronox filter 32.32
The input voltage of the differential amplifier circuit 6 is smoothed by being filtered by the b diode 32a, and an output voltage proportional to the rotation speed is obtained. Rono Kusu Filter 32.32
The smoothing effect by b filters only the above-mentioned 20 kilocycle pull voltage, and the slight pull voltage (usually about 1000 cycles) remains due to changes in the strength of the magnetic field. In place of diode 32 a
It is more effective to use a buffer amplifier with an amplification factor of 1.

As can be seen from the above theory, Schmitt trigger circuit 3
Since an armature current proportional to the input voltage at the input terminal 31b of the transistor 11 is obtained and the transistor 11 is always operated in the saturation region, the Joule loss is effectively minimized. Considering the operation of the members with the same symbols in Fig. 1, the first
In both FIG. 6 and FIG. 6, the armature current proportional to the output of the operational amplifier 8 is applied, so it is clear that the ripple torque is completely eliminated.

Moreover, other effects are also exactly the same. Therefore, it is effective to use it as an electric motor for driving a capstan.

In this embodiment, since the transistor 11 is always operated in the saturation region, the position sensing electric pulse via the output of the Hall element described above in FIG.
0 or by inputting a position sensing electric pulse from a device indicated by symbol 10c into the electric circuit 10 to obtain a position sensing electric signal proportional to the rotational speed. Next, I will explain the details.

In FIG. 5, a brush 22e has been added, which is located at a position intermediate between brushes 22a and 22b. Assuming that the commutator is rotating counterclockwise, when the brushes 22b are separated from the commutator pieces 20b, the magnetic energy stored in the armature coil 21b will cause the brushes 22c' and the resistors 22d to The positive electrical pulse at that time is obtained from the terminal. Since such electric pulses are three pulses per rotation, position sensing electric pulses can be obtained. In the embodiment of FIG. 112, the above-described position sensing device is designated by the same symbol 10C and can be or is used in the same manner.

Incidentally, it is necessary that the opening angle between the brushes 22b and 22c in FIG. 5 be smaller than 90 degrees. In reality, it is better to set it to India.

The one shown in FIG. 7 has a multiplication circuit 2 instead of the division circuit 7.
This is an embodiment in which the armature current control means similar to that shown in FIG. 6 is applied.

Items with the same symbols as 7th □Oi 7, □6, and □ψ- are the same members, and their functions and effects are also the same.

Similar to the embodiment shown in FIG. 6, an armature current I corresponding to the output of the operational amplifier 8 is applied via the Schmitt trigger circuit 31 and the transistor 11. The input of the multiplier circuit 4 is the output of the differential amplification circuit 6 (H, +H2+H,)
From the voltage proportional to the voltage and the voltage drop across the resistor 3, the output of the multiplier circuit 4 to which the voltage proportional to the armature current I with ripple voltage removed is input is I (H, +H2+HI
), that is, it is proportional to the output torque, and this value is
An armature current is supplied through an operational amplifier 8 so as to have a value corresponding to the output voltage of the electric circuit 10, and synchronous operation is performed.

Therefore, there is an effect that ripple torque is also removed.

Other effects are also exactly the same as the embodiment shown in FIG.

The Schmitt trigger circuit 31 may be any other amplification circuit having hysteresis characteristics that performs the same function.

Next, the embodiment shown in FIG. 3 obtains a back electromotive force by detecting the voltage between both input terminals of the motor and the voltage drop of a resistor connected in series, without using a well-known bridge circuit. It has one characteristic in that it is The details of the device of the present invention having the above-mentioned features will be described below.

In Figure 3, symbol 2 is a DC motor, for example a 3-phase Y
It is a commutator motor with type wiring. Transistor 11, resistor 3, and DC motor 2 are connected in series. Symbol 1 is the positive terminal of the power supply.

The resistance value of the armature coil is R91, and the resistance value of resistor 3 is R1.
% Back electromotive force E1 The voltage at the points C and D is V, respectively.
, V, , If the armature current is , then V, = E + I
R, + I R,・−・−・=−・−・(5) v2=I
R2・・・・・・・・・・・・(6) From equation (6), we get I = V2 / R2, so by substituting the value of and into equation (5), we get Vr = E 10 (Rr + R2,) Vz / R'2 Therefore, Vl 2 V2' (J+R+ /R2) = E・"-
...(becomes a force. Since I+R and /R2 are constants, the voltage v1 at the point of symbol C is applied to the input terminal 6a- of the differential amplifier circuit 60.
is input, and the voltage V! at the point marked with the symbol is input to the terminal 6b. If the input voltage v2 of the terminal 6b is multiplied by (I+R1/Rg) and calculated, the output of the differential amplification circuit 6 becomes E, that is, the back electromotive force. The output of the differential amplification circuit 6 and the output of the electric circuit 10 are input to the division circuit 7. A voltage proportional to the electric machine pre-current, which is the output of the divider circuit 7 and the voltage drop across the resistor 3, is input to the operational amplifier 8.

Components with the same symbols as the embodiment in FIG. This is because the position detection electric pulses are inputted via the electric circuit 10KFi, the bypass filter 9, and the commutator and brake by means similar to those in the previous embodiment. In the case of a semiconductor motor, the bypass filter 9 is removed and the output of the Hall element, which is a position detection element, is amplified to form a rectangular wave, and the differential pulse of the front edge of the square wave is obtained, which is proportional to the rotation speed. Since the frequency is -, it can be used as an input to the electric circuit 10. This device can be used in the same way as shown as 10e.

It is clear that the same objective can be achieved by applying the means for eliminating Joule loss using the unit trigger circuit 31 described in FIG. 6.7 to the embodiment of FIG. 3, so a description thereof will be omitted. do.

As can be seen from the description of each of the embodiments above, the apparatus of the present invention achieves the object stated at the beginning and is highly effective.

[Brief explanation of the drawing]

Figure 1 is an electrical circuit diagram of the device of the present invention, Figures 2 and 3'
4 is a graph of the voltage curve on the collector side of transistor l, FIG. 5 is an explanatory diagram of a Y-type three-phase DC motor, and FIGS. FIG. 7 is an electric circuit diagram of another embodiment of the device of the present invention, and FIG.
The graph of the armature current of the example shown in FIG. 6.7, and FIG.
Phase discrimination circuit diagram for synchronous operation, Figure 1θ is a time chart of the voltage of each part in Figure 9, Figure 11 is a detailed electric circuit of a part of the electric circuit in Figure 9, Figure 12 is , respectively show time charts of the electric circuit of FIG. 1...Power supply positive terminal, 2...DC motor, 3
．． 3a, 4.5... Resistor, 6... Differential amplification circuit, 7... Division circuit, 8... Operational amplifier, 9
... No. 1 pass filter, No. 10... Phase discrimination circuit,
11... Transistor, 31... Schmitt trigger circuit, 12.12a, 12b, 12d, . . . = ) transistor, 29-... Multiplication circuit, 27.27a, 27b
...voltage graph on the collector side of transistor 1,
21a, 21b, 21c...armature coil, 20a
120b, 20C... Commutator, 22m, 22b, 22
cm brush, 39.40--graph of armature current,
10C...device for obtaining position detection electric pulses, lOb
... Synchronization signal generator, 44 ... Phase discrimination circuit,
43.55.56...Flip-flop circuit, '5
as45b...Semiconductor switch, 47, Hammer...Transistor 1.49a, 49b...Synchronizing signal electric pulse, 50a, 50°b...Position detection electric signal, 51
m, 51 b, 51 c, 51 d ・-
Output pulse of phase discrimination circuit, 52...capacitor 46
voltage curve, 54... Reversible counting circuit, 53... Differentiating circuit, 57 a, 57 b --... Synchronizing signal, 58
aX58b..., 59a, 59b... Position detection electric signal. Patent applicant: Seko Giken Co., Ltd. Figure l, Figure 4, Figure 4, Figure q, Figure I, ff, Figure 12, Procedural amendment (voluntary), July 2, 1980, Commissioner of the Japan Patent Office Shima 1) Haruki Tono1, Display of the case 1982 Patent Application No. 195717 2 Name of the invention DC motor with synchronous control 3 Relationship to the case Patent applicant 1-20-3 Jingumae, Shibuya-ku, Tokyo 150 Voluntary amendment 5, the detailed explanation column of the invention in the specification subject to amendment and Figure 2 of the attached drawings,
Figure 6% Figure 7, Figure 1o. 6. Contents of amendment tl) Line 11 from right above No. 9 of the specification “゛Kame y<
The electric circuit including +Jo path is corrected to the precept circuit 110J including the electric circuit 10b. (2) On page 11 of the specification, lines 12 to g14 from the top, "the pulse width becomes smaller" is corrected to "the pulse width becomes larger". (3) Second line from the top of page 11 of the specification: "Pulse width becomes larger. Jul"rPulse width becomes smaller. ”. (4) Line 11 from the top of page 11 of the specification “Figure 10 (
d)” is corrected to “Fig. 10(e)”. (5) "+2 or -2 or more" in the fifth line from the top of page 13 of the specification is corrected to "+2 or more or -2 or less". (6) Lines M13 to 14 from the top of page 26 of the specification “
The above-mentioned Tahalus voltage is Since it is filtered by a low-pass filter composed of a resistor 4.5 and a capacitor 32b, it is corrected to ``. (7) “32°32” on the 17th line from the 26th line of the specification
Delete bJ money. (8) Delete "It is even more effective to use a buffer amplifier with an amplification factor of 1 in place of the diode 32m in place 9 of the diode 32m" in line G1 to line A2 from the top of No. 27 of the specification. (9) Lines 19 to 20 from directly above No. 28 of the specification
It is necessary that the opening angle be smaller than 90 degrees. In reality, "about 60 degrees" is corrected to "the opening angle is actually about less than 60 degrees." . (II Figures 2, 6, 7, and 1G of the attached drawings)
Correct the figure as shown in the attached sheet. That’s all for 2 tea gardens! 4.6. Figure No. F No. fO shout

Claims (5)

[Claims] (1) A back electromotive force detection circuit that outputs the back electromotive force of a DC motor having a rectifier, a position detection device that detects the rotational position of the DC motor and generates a position detection electrical signal, and a synchronous signal. An armature current control circuit that uses the output obtained from the detection circuit to control a transistor inserted in series in the armature circuit. A synchronously controlled DC motor characterized by: (2) A synchronously controlled DC motor according to claim 11, characterized in that a DC motor having a three-phase Y-connection armature is used. (3) In the claim set forth in paragraph (1), a flywheel diode connected in parallel to an armature current detection circuit and a series connection body of a DC motor, and an output so as to perform base control of a transistor. is connected and the first input becomes larger than the second input by more than the first set value, the aforementioned transistor becomes non-conductive and the second
an amplifying circuit that has a hysteresis characteristic similar to a Schmitt trigger circuit that causes the transistor to conduct in the saturation region when it decreases beyond a set value; and a control circuit that controls the second input of the amplification circuit, wherein the product of the armature current and the output of the back electromotive force detection circuit is the input of the amplification circuit. Direct current motor. (4) In the claim set forth in paragraph (1), a position sensing electric signal is generated through a change in impedance between the emitter and the collector of a transistor due to a change in the combined resistance of the armature coil when rectification is performed. 1. A direct current motor subject to synchronous control, characterized in that it is comprised of a position detection device that obtains the following: (5) In the claims set forth in paragraph (1),
A third brush is placed between the first and second brushes that come into sliding contact with the commutator.
A position detection device which is provided with a brush and obtains a position detection electric signal by extracting the magnetic energy of the coil through a third brush when one of the Y-shaped armature coils is de-energized. A synchronously controlled DC motor characterized by comprising: