JPH10225406A - Vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a phase deviation between AC commercial power waveform and a power frequency signal and to improve the precision of phase control to improve an inhaling work rate by permitting a commercial AC power waveform to be the input of a direct power frequency detecting circuit. SOLUTION: The power frequency detecting circuit 10a adopts the AC commercial power waveform as the direct input and the power frequency signal being its output waveform reduces the diviation of phase difference with AC commercial power voltage wave. When a microcomputer 9 detects the rising and falling of the power frequency signal, a timer in the microcomputer 9 is started. When the timer counts a prescribed time, the microcomputer outputs a trigger signal so that a triac 18 becomes a continuity state and current is permitted to flow in a motor-driven blower 2. A time till the microcomputer 9 outputs a triac driving pulse, that is, an ignition phase angle is fixedly kept so that the input to the motor-driven blower 2 is kept fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vacuum cleaner.

[0002]

2. Description of the Related Art In a vacuum cleaner, a power supply frequency signal is generated by a power supply frequency detection circuit, and phase control is performed using the power supply frequency signal as a reference signal. In the conventional power supply frequency detection circuit, the voltage on the secondary side of the power supply transformer is used as an input to the circuit, and the power supply frequency signal, which is the output waveform, has a full-wave system, that is, a waveform of two pulses per one cycle of the AC commercial power supply voltage. The microcomputer detects the falling edge of each pulse, interrupts it, and performs various processes.

[0003]

In the phase control, the phase of the voltage waveform applied to the electric blower is controlled on the basis of the detection point of the power supply frequency signal. Ideally, the zero-cross points (points at which the voltage becomes 0) coincide. However, in such a conventional power supply frequency detection circuit, the input to the power supply frequency detection circuit is taken from the secondary side of the power supply transformer. At the stage of the input signal for generating the power supply frequency signal, a phase shift from the AC commercial power supply waveform already occurs. In addition, the phase shift is not simply constant, but changes depending on the current consumption on the secondary side of the power transformer. At present, it is desired to increase the input at the power peak point in the suction power competition, but since the amount of deviation between the power frequency signal detection point and the AC commercial power waveform is not constant, the phase deviation Input control must be performed in consideration of the fluctuation.

FIG. 4 shows an AC commercial power supply voltage and a power supply frequency signal.
(Example of a conventional system), a trigger signal for turning on an electric blower, a voltage between terminals of the electric blower, and a relation between a power supply frequency signal detection point and an input to the electric blower are shown. The phase control is performed by increasing or decreasing the firing phase angle θ, which represents the time from the power supply frequency signal detection point shown in FIG. 4 until the trigger signal for turning on the electric blower is output.
The current firing phase angle is defined as θ1. The normal power supply frequency detection point is point b, and the input to the electric blower at that time is Wb
And When the power supply frequency signal detection point shifts to the point a, the power supply frequency signal detection point is earlier than the point b, so that the output point of the trigger signal output after a fixed time from the detection point is earlier than the point b. Therefore, the ON time of the electric blower becomes longer, and the input Wa of the electric blower at that time becomes larger than Wb.

Conversely, if the power supply frequency signal detection point shifts to the point c, the power supply frequency signal detection point becomes later than the point b.
The output point of the trigger signal output after a fixed time from the detection point is later than the point b at the zero cross point of the AC commercial power supply voltage. Therefore, the ON time of the electric blower is shortened, and the input Wc of the electric blower at that time becomes smaller than Wb. Even though the firing phase angle θ1 is the same, a difference appears in the input of the electric blower due to the variation in the power supply frequency signal detection point, and the accuracy of the input control deteriorates.

Therefore, in order to perform more accurate phase control, it is necessary to reduce the difference between the points b and a and between the points b and c, that is, the variation in the power frequency signal detection points.

The present invention has been made to solve the above problems, and
By using the commercial AC power supply waveform directly as the input to the power supply frequency detection circuit, the phase shift between the AC commercial power supply waveform and the power supply frequency signal is reduced, improving the accuracy of the phase control and accompanying suction power. With the goal.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is characterized in that a power supply frequency detecting circuit for detecting a frequency of an AC commercial power supply, and a current detecting circuit for detecting a current of the electric blower. Current detecting means, a signal converting means for converting an output of the current detecting means into a level signal, and a phase controlling means for controlling an input of the electric blower by an output of the signal converting means, and comprising: Directly as an input to the power frequency detection circuit,
It is an object of the present invention to reduce a phase shift between an AC commercial power supply waveform and a power supply frequency signal output from the power supply frequency detection circuit, thereby improving the accuracy of phase control.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

The vacuum cleaner has a configuration as shown in FIG. The dust collecting chamber 4 and the electric blower 2 are provided inside the cleaner body 1.
, And the hose 5 is connected to the cleaner body 1. At the connection between the hose 5 and the extension pipe 7, there is provided a hand operation unit 6 for setting a suction force or the like of the electric blower 2, and the main body control unit 3 is controlled so that the suction force set here is attained. Is controlled by. A suction port 8 is connected to the tip of the extension tube 7. The main body control unit 3 built in the main body 1 of the vacuum cleaner has a circuit configuration as shown in FIG. 1, a hand operation unit 6 for setting a suction force, and a current detection for detecting a current of the electric blower 2. Means 14, a signal converting means 15 for converting the output of the current detecting means to a voltage of a constant level, a pressure sensor circuit 16 for detecting the degree of vacuum in the dust collecting chamber 4 in FIG. A power transformer 12, which converts the power into DC power and supplies it to the entire control circuit;
Power supply circuit composed of 5V constant voltage section 13, AC commercial power supply 11
A power supply frequency detection circuit 10a for detecting the frequency of the power supply, a microcomputer (hereinafter referred to as a microcomputer) 9 which performs arithmetic processing, and a clock oscillation circuit 19 for generating a clock frequency signal for operating the microcomputer; A display circuit 20 for externally displaying the operation state of the fan using a light emitting diode or the like, a bidirectional semiconductor element (hereinafter referred to as a triac) 18 for switching the electric blower, and a triac 18 are turned on by a trigger signal from the microcomputer 9.
It comprises a motor drive circuit 17 for N-OFF.

A configuration of a control circuit according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit block diagram of one example of an embodiment of the present invention, FIG. 2 is a configuration diagram of a vacuum cleaner of one example of an embodiment of the present invention, and FIG. 3 is a circuit including an example of a conventional power supply frequency detection circuit. FIG. 4 is a block diagram showing the relationship between the AC commercial power supply voltage, the power supply frequency signal, the trigger signal, the voltage between the electric blower terminals, the power supply frequency signal detection point, and the input of the electric blower.

The main body control section 3 is constituted mainly by a microcomputer 9. The trigger signal from the microcomputer 9 is the motor drive circuit 1
When the triac 18 is sent to the gate terminal of the triac 18 via the switch 7, the triac 18 becomes conductive and the electric blower 2
Rotates. Accordingly, in FIG. 4, if θ1 is reduced, the conduction time of the electric blower 2 is increased, so that the input of the electric blower 2 is increased. If θ1 is increased, the conduction time of the electric blower 2 is reduced, and the electric blower 2 is reduced. Input becomes smaller. The power supply frequency detection circuit 10a generates a power supply frequency signal serving as a reference for phase control. Microcomputer 9
Detects the rise and fall of the power supply frequency signal alternately, and performs frequency judgment and phase control based on the detected rise and fall. The power of the main body control unit 3 is converted from an AC commercial power supply 11 to a DC power supply by a power supply circuit and supplied to the entire control circuit. The current detecting means 14 detects the current of the electric blower 2 and outputs an AC signal. The AC signal output from the current detecting means 14 is converted by the signal converting means 15 into a level signal having a predetermined value. The converted level signal is input to an A / D conversion input port of the microcomputer 9.

The pressure sensor circuit 16 detects the degree of vacuum in the dust collection chamber 4 and converts it into a level signal,
Output to the / D conversion input port. The microcomputer 9 can recognize the degree of clogging of the filter of the dust collection chamber 4 from the value. Hereinafter, the operation in this configuration will be described.

When the microcomputer 9 detects the rise or fall of the power supply frequency signal, the timer in the microcomputer 9 starts. When the timer counts a predetermined time, the microcomputer 9 outputs a trigger signal, whereby the triac 18 is brought into a conductive state, and a current flows through the electric blower 2. A value obtained by converting the time from when the timer starts counting until the microcomputer 9 outputs the triac drive pulse to a sine wave angle is called a firing phase angle. By keeping this firing phase angle constant, the input to the electric blower 2 can be kept constant.

FIG. 3 shows an example of a circuit using the conventional power supply frequency detection circuit 10b. In the conventional power supply frequency detection circuit 10b, the voltage on the secondary side of the transformer 12 is input, and the power supply frequency signal which is the output waveform is as shown in FIG.
Detects its fall.

On the other hand, the power supply frequency detection circuit 10a of FIG. 1 according to the present invention directly receives the AC commercial power supply waveform, and the power supply frequency signal as the output waveform is as shown in FIG. And fall are detected alternately. The timer actually starts counting from the time when the microcomputer 9 detects the power supply frequency signal. However, if a deviation occurs between the detection time of the power supply frequency signal and the zero-cross point of the commercial AC power supply waveform, According to the calculation of the microcomputer 9, even if the firing phase angle is the same, a difference appears in the actual input to the electric blower 2. In the conventional power supply frequency detection circuit 10b, the input to the power supply frequency detection circuit is via the transformer 12.

Due to the current consumption on the secondary side of the transformer, the voltage between the primary side of the transformer and the secondary side voltage becomes
A phase shift occurs. In addition, since the current consumption on the secondary side of the transformer is not constant but fluctuates constantly, the power supply frequency detection circuit receives the voltage on the primary side of the transformer, that is, the AC commercial power supply voltage and the voltage on the secondary side of the transformer. There is a phase variation between the power supply frequency signals output from 10b.

In the power supply frequency detection circuit 10a according to the present invention, the AC commercial power supply waveform is directly input to the power supply frequency detection circuit, and the phase shift between the AC commercial power supply voltage and the power supply frequency signal through a transformer is detected. Lost.

Next, an embodiment of a vacuum cleaner using the present invention will be described. FIG. 7 shows the degree of vacuum H, the power consumption Wi, and the suction power P with respect to the air volume Q when the power control is not performed.
Is shown by a two-dot chain line, and an example of the relationship between the degree of vacuum H 'and the suction power P' with respect to the air flow Q when the power consumption is controlled like Wi 'is shown by a solid line.

In general, the relationship between the power consumption Wi and the degree of vacuum H with respect to the air volume Q is, as shown by the two-dot chain line in FIG. 7, the vacuum level H is low on the large air volume side (in a state where dust is not accumulated). Since the load (air load) of the electric blower 2 increases, the current flowing through the electric blower 2 also increases. Therefore, the power consumption Wi also increases. Conversely, on the small air volume side (in a state where dust is accumulated), the degree of vacuum H increases, but the current flowing through the electric blower 2 decreases, and the power consumption Wi also decreases. The suction power P is P = Q × H ×
0.1634 (W), which results in a curve as shown in FIG.

However, there is a legally prescribed value for the power consumption of the vacuum cleaner, and in order to obtain a higher suction power without exceeding the upper limit, the power consumption near the suction power peak point should be monitored. It is necessary to perform constant input control so that the power consumption, that is, the input to the electric blower becomes the highest in the vicinity.

In FIG. 7, Qp 'is the airflow at the suction power peak point, and constant input control of Wi' is performed in the vicinity of Q1≤Q≤Q2. An example of the embodiment of the present invention will be described in the range of Q1 ≦ Q ≦ Q2 near the suction power peak point. First, the signal conversion means 1 based on the signal from the hand operation unit 6
The reference value W for controlling the signal level of No. 5 to be constant
Determine i′1. The electric blower 2 is controlled so that the power consumption Wi ′ obtained by calculation from the output level of the signal conversion means 15 based on the determined Wi′1 becomes a constant value Wi′1.
Control.

For example, when dust accumulates in the dust collecting chamber 11, the air volume Q decreases. When the air volume Q decreases, the load (air load) of the electric blower 2 decreases, so that the current value decreases. When the current detection unit 14 detects the change in the current, the output signal level of the signal conversion unit 15 decreases, and the value of power consumption calculated by the output voltage of the signal conversion unit 15 becomes lower than the reference value Wi′1. Then, the microcomputer 9 advances the firing phase angle so as to increase the current value of the electric blower 2, that is, shortens the time from the detection of the power supply frequency signal to the output of the triac drive pulse, and reduces the current value of the electric blower 2 to the original value. Power consumption W determined to return to the level, that is, the product of the current value and the voltage applied to the electric blower 2.
It works to increase i ′ and return to the reference value Wi′1.

When the dust is removed, the air volume Q increases. When the air volume Q increases, the load (air load) of the electric blower 2 increases, the current value increases, the change in the current is detected by the current detection unit 14, the output signal level of the signal conversion unit 15 increases, and the signal conversion takes place accordingly. The value of the power consumption calculated by the output voltage of the means 15 rises from the reference value Wi′1. Then, the microcomputer 9 delays the firing phase angle so as to reduce the current value of the electric blower 2, that is, increases the time from the detection of the power supply frequency signal to the output of the triac drive pulse, and reduces the current value of the electric blower 2. In order to return to the original level, that is, reduce the power consumption Wi ′ obtained by multiplying the current value and the voltage applied to the electric blower by reducing the reference value W
It works to return to i'1.

Therefore, if the phase difference between the power supply frequency signal and the power supply voltage waveform is reduced by the improvement of the power supply frequency detection circuit, the theoretical and actual shift of the ignition phase angle, that is,
The difference between the calculated power of the microcomputer and the power actually consumed by the electric blower is reduced, and the accuracy of the phase control can be improved.

[0026]

As described above, according to the present invention, the power supply frequency detecting circuit for detecting the frequency of the AC commercial power supply waveform, the current detecting means for detecting the current of the electric blower, and the output of the current detecting means are provided. A signal converting means for converting the signal into a level signal; and a phase control means for controlling an input of the electric blower by an output of the signal converting means, wherein the power supply frequency detection circuit directly receives a commercial AC power supply waveform. By reducing the phase shift between the commercial AC power supply waveform and the power supply frequency signal that is the output of the power supply frequency detection circuit, a more accurate signal level of the signal conversion means is maintained. High phase control can be performed.

Further, since the power supply frequency detection circuit according to the present invention has a direct input of a commercial AC power supply waveform, it can be diverted to a transformerless circuit as it is, and has the advantage of sharing the circuit.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of an example of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a vacuum cleaner according to an example of an embodiment of the present invention.

FIG. 3 is a circuit block diagram including an example of a conventional power supply frequency detection circuit.

FIG. 4 shows a relationship among an AC commercial power supply voltage, a power supply frequency signal, a trigger signal, an electric blower terminal voltage, a power supply frequency detection point, and an electric blower input.

FIG. 5 shows an AC commercial power supply waveform and a power supply frequency signal which is an output of the power supply frequency detection circuit 10a according to the present invention.

FIG. 6 shows an AC commercial power supply waveform and a power supply frequency signal output from a conventional power supply frequency detection circuit 10b.

FIG. 7 is a diagram showing a relationship among air volume-vacuum degree, power consumption, and suction power of the vacuum cleaner according to an example of an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum cleaner main body, 2 ... Electric blower, 3 ... Main body control part, 1
0a: power supply frequency detection circuit.

Continuing from the front page (72) Isao Wada 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Electrification Equipment Division, Hitachi, Ltd. No. 1 in the Sun Tachiga Technology Co., Ltd.

Claims (4)

[Claims] A power supply frequency detection circuit for detecting a frequency of an AC commercial power supply waveform; a current detection means for detecting a current of the electric blower; a signal conversion means for converting an output of the current detection means into a level signal; Phase control means for controlling the input of the electric blower by the output of the signal conversion means,
The electric vacuum cleaner wherein the power supply frequency detection circuit directly inputs a commercial AC power supply waveform. 2. The vacuum cleaner according to claim 1, wherein a rise and a fall of a power frequency signal output from the power frequency detection circuit are detected. 3. The vacuum cleaner according to claim 1, wherein a rising edge and a falling edge of a power supply frequency signal output from the power supply frequency detection circuit are alternately switched and detected. 4. The phase control means according to claim 1, wherein a power supply frequency signal output from said power supply frequency detection circuit is used as a reference signal, and said phase control means controls the ignition phase so that the signal level of said current detection means has an arbitrary value. An electric vacuum cleaner characterized by controlling the input of the electric blower near the suction power peak point to be kept substantially constant by increasing or decreasing the angle.