JPH01268530A - Control circuit for vacuum cleaner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vacuum cleaner, and more particularly to a phase control circuit for a vacuum cleaner using a bidirectional thyristor. This invention relates to a control circuit that utilizes the intersection of a triangular wave synchronized with the power supply frequency and a DC potential that intersects the triangular wave to determine the firing angle.

[Conventional technology]

Conventionally, electric cleaning has adopted a method in which the firing angle of the bidirectional thyristor is determined by the intersection point of the triangular wave as described above and the DC potential that intersects with the triangular wave, and the firing angle of the bidirectional thyristor is made variable by changes in the DC potential. The input control circuit of the machine was developed in 1986.
This is shown in JP-A No. 114231 and the like.

The relationship between this triangular wave and the DC potential is shown in FIG.

The triangular wave and the DC potential are compared by a comparator, and the firing pulse of the bidirectional thyristor is obtained by differentiating the output waveform.

[Problem to be solved by the invention]

However, according to this control method, when the power supply frequency is 5
When the frequency changes from 0Hz to 60Hz, the period of the triangular wave changes, but from the start of the triangular wave's rise,
Since the time it takes to cross the DC potential remains the same, the firing timing of the bidirectional thyristor will be delayed at 60Hz, where the period of the triangular wave is short, than at 50Hz. In this case, the input is smaller than that at 50 Hz, and no consideration has been given to this point.

An object of the present invention is to provide a control circuit that can keep the input control amount unchanged even when the power supply frequency changes to 50/60 Hz.

[Means to solve the problem]

The present invention focuses on the fact that even if the period of the triangular wave changes at 50/60 Hz, the above object can be achieved by preventing the height of the triangular wave peak from becoming lower at 60 Hz. A means is provided to make the height of the triangular wave peak the same at 60 Hz. That is, by employing such means, the firing angles of the bidirectional thyristors can be made the same even when compared at the same DC potential.

Specifically, 1. For example, when the charging voltage in a capacitor charging circuit for generating a triangular wave is 60Hz, it is 50H.
This is achieved by setting it higher than the time z.

[Effect]

A triangular wave can be obtained by repeatedly charging a capacitor from a constant voltage through a resistor and discharging it when the power supply waveform crosses zero, but in order to make the constant voltage for charging larger at 60Hz and 50Hz, the voltage at 60Hz is larger. The following methods were used.

A filter circuit is connected to the power supply waveform, and its output voltage is
Subtracting from the power supply voltage for the control circuit, which is constant regardless of the power supply frequency, the output voltage of the filter circuit is 5.
It is larger at 0Hz than at 60Hz, but if you subtract this from the control circuit power supply voltage, it will be reversed and the value at 60Hz will be 5.
A higher potential can be obtained than at 0 Hz. The above object is achieved by using this output voltage as a triangular wave charging voltage.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is an overall diagram of a control circuit according to this embodiment.

FIG. 2 is a detailed diagram of the main control circuit in FIG. 1.

In FIG. 1, one end of the AC 100V power supply serves as the ground potential for the entire control circuit, and the other end is connected to the control circuit and the electric motor of the vacuum cleaner. Power supply circuit 1 outputs DC power supply Vcc for the entire control circuit 6 Aftermath rectification circuit 2 outputs AC100
A waveform obtained by rectifying the V power supply is output, and this is input to the main control circuit 3.

Next, the output potential vt of the filter circuit composed of resistors 4, 5.6 and capacitor 7 is inputted to the inverting input terminal of operational amplifier (hereinafter referred to as operational amplifier) 9 via electrolytic capacitor 8. On the other hand, the non-inverting input terminal of the operational amplifier 9 receives the DC power supply Vcc, which is the output of the power supply circuit 1 .

The operational amplifier 9 constitutes a differential amplifier circuit using external resistors, and outputs the difference between the Vcc and the filter circuit output voltage Vffi. Here, the output voltage vt of the filter circuit is naturally 5 when comparing the AC100■ power frequency with 50H2 and 60Hz.
It is higher at 0Hz than at 60Hz. On the other hand, the DC power supply Vcc is 50Hz.

Since it is constant regardless of 60fIz, if the output potential of the operational amplifier 9 is Vpp, then Vpp=G (Vcc-vl) (here, G is the external resistance of the operational amplifier 9 with a resistance of 10°11.
This is the gain of the differential amplifier circuit that can be arbitrarily determined by the resistance values of 12 and 13. ), and Vpp is 50
Hz Toro ciHz (1) Time Teha, Vpp (50Hz
) < Vpp (at 60l-1z) is output. This Vpp is applied as a triangular wave charging voltage within the main control circuit 3, which will be described later.

Next, the main control circuit 3 is a circuit that receives output from a hand control switch of a vacuum cleaner hose (not shown) or a pressure sensor (not shown) built into the vacuum cleaner, and determines the operating state of the electric motor 14. , outputs a trigger pulse for firing the bidirectional thyristors 15 and 16. The output trigger pulse of the main control circuit 3 is connected to the base of the transistor 17. Further, the collector is connected to the DC power supply VCC, and the emitter is connected to the gate of the bidirectional thyristor 15 via a resistor.

When a trigger pulse is supplied to the base of the transistor 17, the -Larranged metal 1 is turned on, gate current and voltage are applied to the bidirectional thyristor 15, and the bidirectional thyristor 15 is turned on.

Then, current and voltage are similarly applied to the gate of the bidirectional thyristor 16, the bidirectional thyristor 16 is also turned on, and the motor 14 is energized.

Diode 18. Resistance 19. The Zener diode 20 and the electrolytic capacitor 21 constitute a power supply circuit in the main control circuit 3 that generates a DC power source Voo for supplying current to a variable resistor built into the hand hose of the vacuum cleaner.

Next, the main control circuit 3 will be explained in detail with reference to FIG. The aforementioned DC power supply Voo is connected to the resistor 22. Switch 23゜Variable resistor 24
Alternatively, it is lowered to the ground potential via the resistor 25 and further through the resistor 26. Illustrated - switch 23 surrounded by dot-dashed lines
．． Variable resistance 24. The resistor 25 is built into a hose hand control section (not shown) of the vacuum cleaner so that it can be operated by a user.

First, in the first case, the switch 23 is the variable resistor 2
The case where it is connected to the 4th side will be explained. Power supply Vo
The voltage due to resistor 22. Variable resistance 24. The voltage is divided by the resistor 26, and the potential across the variable resistor 24 is V1. V! can be arbitrarily changed by the value of the variable resistor 24.

vl and v2 are input to a differential amplifier circuit formed by an operational amplifier 29 through a buffer formed by operational amplifiers 27 and 28, and the output voltage vo is vo ==
G (v i −v2), where G is the gain of the differential amplifier circuit.

The output voltage vo is further input simultaneously to an inverting input terminal of a comparator 30 and a non-inverting input terminal of a comparator 31. On the other hand, a comparison potential v4 divided from the power supply voltage Vcc by resistors 32, 33, and 34 is input to the non-inverting input terminal of the comparator 30, and v8 is similarly input to the inverting input terminal of the comparator 31. A connecting the respective output terminals of comparators 30 and 31
The output potential at the point is low level when the input voltage vo is below V♂, high level in the range from ■δ to v4, and low level when it is above v4. That is, the input voltage vo is from v8 to v
The circuit outputs a high level only in the range of 4, and a low level in other cases. In the first case currently discussed here, the switch 23 is connected to the variable resistor 24.
When the resistance value of the variable resistor 24 is at its maximum when the variable resistor 24 is connected to the side, vO is also at its maximum, but this is set within a range that does not exceed v8, so that the output at the point A is at a low level.

Furthermore, the point A is connected to the control terminals A and B of the analog switch 35 via diodes 36 and 37, respectively, and no matter what output level is input to the control terminals A and H from other circuits, the All the signals become low level through the diodes 36 and 37, and the connection between the output X and the input Xa of the analog switch 35 is turned on. In this case, since the VD is connected to Xo, the output X of the analog switch 35 is connected to the VD.
O will appear. Here, the values of control manual power A and B of the analog switch 35 and the on-channel Xo"
Table 1 shows a truth table showing the relationship between Xa. In the table, L represents low level and H represents high level.

According to the explanation above in Table 1, the output X of the analog switch 35 has V.
D is output, and this vo is further input to the inverting input terminal of the comparator 38. On the other hand, the non-inverting input terminal of the comparator 38 is connected to the triangular wave charging voltage Vpp via a resistor 39 and grounded via a capacitor 40. Furthermore, it is connected to the output of the comparator 42 through a resistor 41,
The output of this comparator 42 is connected to the output terminal of the comparator 38 via a diode 43. Here, the operation of this embodiment consisting of these circuit configurations will be explained with reference to FIG.

FIG. 3(1) shows the full-wave rectified waveform input to the non-inverting input terminal of the comparator 42 and the potential level input to the inverting input terminal at the same time.

FIG. 3(2) shows the output waveform as a result of comparing these, and a rectangular wave that becomes low level with a certain width centered around the zero point of the aftereffect rectified waveform is output. The width of this low level is such that the potential input to the inverting input terminal of the comparator 42 is
When determining the resistor 43.45, it can be arbitrarily set by selecting its voltage division ratio. Next, the waveform of the inverting input terminal of the comparator 38 is shown in FIG. 3 (3). When the comparator 42 becomes high level, the capacitor 40 is charged by the triangular wave voltage Vpp through the resistor 39, and the potential at the non-inverting input terminal of the comparator 38 rises as the capacitor 40 is charged. Next, when the comparator 42 becomes low level, the charge stored in the capacitor 40 is transferred to the resistor 41. diode 46
is sucked into the output terminal of the comparator 42 through the capacitor 4
A charging potential of 0 becomes a low level. At this time, the potential of the capacitor 40 is discharged to the output terminal of the comparator 42 through the diode 46, so the low level output potential of the comparator 42 (
The valve is discharged only to a potential that is about 0.6 to 0.7 V higher than the valve ground potential by the forward voltage drop of the diode. From the above, a triangular wave synchronized with the power supply frequency as shown in FIG. 3(3) is created. At this time, the bottom of the triangular wave is raised above the ground potential by the forward voltage of the diode, as described above.

FIG. 3(3) shows VD input to the inverting input terminal of the comparator 38 at the same time as the triangular wave, and FIG. 3(4) shows the output of the comparator 38 as a result of comparing them. The outputs of the comparators 38 and 42 are connected via a diode 43, which is input to the inverting input terminal of the comparator 47 (
The waveform is shown in Figure 3 (5)). As can be seen from the figure, the inverting input terminal of the comparator 47 is at a high level only when both outputs of the comparators 38 and 42 are at a high level, and is at a low level otherwise. Furthermore, the comparator 47 has the function of an inverter, and converts the rectangular wave at the inverting input terminal to v
4 (comparison potential applied to the non-inverting input terminal of the comparator 47) is output, and a rectangular wave inverted with reference to it is output, as shown in FIG. 3 (6).

When the output of the comparator 47 is low level, the power supply voltage Vc
A capacitor 49 is charged from c through a resistor 48.

Next, when the output of the comparator 47 becomes high level, the charge in the capacitor 49 that was charged while the output was low level is
This time, it is discharged to the Vcc side through the diode 50, and the potential across the capacitor 49 becomes Vcc and settles down. Therefore, the voltage at the right terminal of the capacitor 49, that is, the voltage waveform at the inverting input terminal of the comparator 51, is Vc at the moment the output of the comparator 47 switches from low level to high level.
Forward voltage drop of diode 5o from c approximately 0.6 to 0
．． It jumps up to a point where it has increased by about 7V, but capacitor 4
As the discharge of 9 occurs, Vcc' settles to 1. This waveform is shown in FIG. 3 (7). In FIG. 3 (7), the comparator 5
The comparison potential V11 applied to the non-inverting input terminal of 1 is shown at the same time, and the output as a result of comparison with the waveform of the inverting input terminal is shown in FIG. 3 (8). The width of the pulse appearing in FIG. Resistance 48. It can be set arbitrarily by changing the comparison potential v5.

To summarize the above explanation, when looking through Figure 3 (1) to (8), at the point where the triangular wave synchronized with the power supply frequency and the potential difference VO across the variable resistor 24 at the hose end cross, Figure 3 The pulse shown in (8) is output, and using this as a trigger pulse, the transistor 17 of FIG.
The input phase of the motor 14 can be controlled by applying it to the base of the motor 14.

In input phase control, when the user changes the value of the variable resistor 24 at the hose end, the potential of VD goes up and down, and the point of intersection with the triangular wave changes, so the timing of trigger pulse generation relative to the power supply frequency changes, and the motor 14 is controlled from weak operation to strong operation.

Next, in the case where the potential difference VD across the variable resistor 24 is less than a triangular wave, waveforms at each point are drawn in the same way as in FIG.

In this case, the triangular wave and VD do not cross, so comparator 3
The output of the comparator 47 ((4) in FIG. 4) remains at a high level, but as mentioned above, it is AND-coupled with the output of the comparator 42, so the non-inverting input terminal of the comparator 47 has the above-mentioned comparator output. The zero-cross pulse which is the output of the device 42 is inputted, and based on this, a trigger pulse similar to that described above can be generated at the point in time when the triangular wave rises from the trough.

Next, consider a second case in which the switch 23 is in the off position. Similarly to the above, when following the potential signal, since the switch 23 is off, Vl is Voo,
v2 becomes the ground potential.

VD:G (MI Vll) becomes vo=GVoo.

If VD at this time is set to Vl so that it is higher than the comparison potential v4, the potential at point A connecting the outputs of both comparators 30 and 31 will be low level, and in the first case Similarly, vo is connected to the output X of the analog switch 35. Furthermore v.

If is set to be higher than the potential of the apex of the triangular wave, the output of the comparator 38 will always be at a low level and the output of the comparator 47 will remain at a high level when compared with the triangular wave. No trigger pulse is generated from the output end of the motor 51, and the motor 14 is not operated.

Finally, a third case will be described in which the hose hand switch 23 is connected to the resistor 25 side.

The resistance value of the resistor 25 is set to be larger than the maximum resistance value of the variable resistor 24, and the potential difference VD between both ends of the resistor 25 is set between the comparison potentials v8 and Vl.

In this case, point A, which connects both outputs of comparators 30 and 31, becomes high level. Point A is diode 3 as shown in the figure.
It is connected through 6.37 to the line connecting the control input of the analog switch and the comparator 52.53.

The diodes 36 and 37 face point A from the output side of the comparator 52 and 53, and since point A is at high level,
The control inputs A and B of the analog switch 35 are
The outputs (high or low level) of comparators 53 and 52 are input as they are.

Next, how the outputs of the comparators 52 and 53 change depending on the pressure sensor output will be explained.

The pressure sensor output is simultaneously input to the non-inverting input terminal of comparator 52,55 and the inverting input terminal of comparator 54. Each comparator also has a comparison reference potential V8. V7 has been added. Both output terminals of the comparators 54 and 55 are connected, and the comparator 53 has a function of inverting the potential at the connected point.

Assuming that the output connection point of the comparators 54 and 55 is point B, the potential at point B is at a high level only when the pressure sensor output is between v7 and v8, and is at a low level thereafter.

Therefore, the output of the comparator 53 is an inversion of the potential at point B, that is, the pressure sensor output is at a low level only between v7 and v8, and is at a high level thereafter. On the other hand, when the pressure sensor output is 77 or more, the output of the comparator 52 is
High level, low level when V7 or lower. The output terminals of the comparators 52, 53 are connected to the control input terminals B, A of the analog switch 35, as described above.

Pressure sensor output potential and control input terminal A.

Table 2 shows the relationship between the value of B and the on-channel of the analog switch 35 at that time.

Table 2 H: High level, L: Low level
．． VIO is applied and due to the pressure sensor output potential.

According to the truth table shown above, V♂ to VIG will be output to the output terminal X of the analog switch.

For example, when the output of a pressure sensor increases from zero, Vl will appear at the X terminal of the analog switch.

Since the potentials are output in the order of V e and V 10 and compared with the triangular wave, the motor 14 is automatically switched from a weak input to a strong input one after another. This is done when the suction mouth of the vacuum cleaner is floating above the floor, when the filter is not clogged, the input to the motor 14 is lowered, and when the suction mouth is on the floor, or when the filter is clogged. This enables automatic operation in which the input to the electric motor 14 is increased.

The cases of cylinders 1 to 3 have been described above, and the circuit according to this embodiment determines the 1-rega pulse generation timing for controlling the input of the motor using a triangular wave and the DC potential that intersects with the triangular wave. However, the power frequency is 50Hz and 60Hz.
At the time of , the period of the triangular wave is also shorter at 60Hz, and 5
If you were comparing the same DC potential at 0Hz and 60Hz, the ignition timing would be different between 50H7 and 60Hz.

You will no longer be able to drive on your own.

Therefore, conventionally, there has been a proposal to switch the constant of the resistor 39 or capacitor 40 between 50Hz and 60Hz when charging the triangular wave, but in the case of this embodiment, in order to do this automatically, the charging voltage Vpp of the triangular wave is changed. , in the filter circuit shown in FIG. 1 described above, 50 Hz, 60 Hz
It switches automatically from time to time. That is, the triangular wave charging voltage Vpp is set higher at 60 Hz than at 50 Hz, resulting in 50 Hz and 60 Hz, as shown in FIG.
Set the triangular wave heights X to be the same at Hz. As a result, as shown in Figure 5, from the law of similarity of triangles, the frequency is 50Hz.
The a/A shown in the diagram at the time is the same as the b/B at the time of 60 Hz, and the firing timing of the bidirectional thyristor can be made the same even when the potential compared with the triangular wave is the same.

Further, as another embodiment of this part, the output voltage of the filter circuit is set to the power supply potential Voo to the hand operation part of the hose.
If the height of the triangular wave is 50Hz and 60Hz, even if the height of 60Hz is lower, the DC potential vo compared to the triangular wave will also be lower, so the firing angle of the bidirectional thyristor should be set to 50/60Hz. can be made the same.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize a control circuit in which the input control amount does not change when the power supply frequency is 50 Hz and 60 Hz.

[Brief explanation of the drawing]

Fig. 1 is an overall circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram of the main control circuit of Fig. 1, and Figs. 3 and 4 show a trigger pulse for a bidirectional thyristor. A schematic diagram showing voltage waveforms at each point up to . FIG. 5 is a schematic diagram showing a triangular wave shape at 50 Hz and 60 H)C, and FIG. 6 is a schematic diagram showing a conventional triangular wave. 30th 4th (2) 50th Kusu=

Claims (1)

[Claims] 1. In a circuit that controls the input of an electric blower in a vacuum cleaner using a bidirectional thyristor, the timing for supplying a trigger pulse to the gate of the bidirectional thyristor is set to a triangular wave synchronized with the power supply frequency, and a triangular wave that intersects the triangular wave. 1. A control circuit for a vacuum cleaner, characterized in that the control circuit for a vacuum cleaner is provided with means for making the height of the triangular wave constant regardless of changes in the power supply frequency, the triangular wave being determined by the intersection point with an input instruction potential.