JPH0928640A - Motor controller for vacuum cleaner - Google Patents

Abstract

(57) [PROBLEMS] To provide a motor control device for an electric vacuum cleaner that is small in size and low in cost. A current flowing through a motor 2 is detected by a resistor R11, and when a detection voltage of the resistor R11 becomes a predetermined value or more, a transistor Q3 of a firing pulse level control circuit 6 is detected.
Then, the transistor Q4 is turned on / off every half cycle to control the level of the ignition pulse applied to the gate of the thyristor 3 to control the energization time of the motor 2 and the thyristor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for an electric vacuum cleaner, and more particularly to a motor control device for an electric vacuum cleaner which controls power by detecting a motor current.

[0002]

2. Description of the Related Art A conventional motor control device for an electric vacuum cleaner is provided with an ignition pulse generating circuit including a time constant circuit composed of a resistor, a variable resistor and a capacitor, and is synchronized with a zero cross point of an AC power source. Then, an ignition pulse having a phase corresponding to a time constant is generated, and the ignition pulse is applied to a current control element such as a bidirectional three-terminal thyristor to turn on the current to energize the motor. In this type of vacuum cleaner, when the resistance value of the variable resistor is changed in the larger direction, the time constant of the time constant circuit becomes larger, the phase angle is delayed, the angle at which the motor is energized becomes smaller, and the motor is energized. The current becomes small. On the contrary, when the resistance value of the variable resistor is changed in the small direction, the time constant becomes small, the phase angle advances, the angle at which the motor is energized becomes large, and the energizing current becomes large. Therefore, the motor power can be adjusted by changing the resistance value of the variable resistor.

Further, in a general electric vacuum cleaner, the electric power supply to the motor is restricted when the brush (suction portion) is lifted in the air, that is, when the suction air amount is maximum, and the brush comes into close contact with the surface to be cleaned. At the time, that is, when you want to clean,
It is desirable to increase the power supply. Therefore, the applicant of the present invention, as shown in FIG.
2 connected in series, connected to the AC power supply 23, and when the current control element 22 is turned on, the circuit 24 for energizing the motor 21 and the time constant circuit are included, and the phase angle corresponds to the time constant of the time constant circuit. An ignition pulse generation circuit 25 for generating an ignition pulse in synchronization with the zero cross point of the AC power supply, and the current element 22 with the ignition pulse applied to the current control element 2
2. The ignition circuit 26 for turning on 2, the current detection circuit 27 for detecting the current flowing through the current control element 22, and the time constant control circuit 28 for changing the time constant of the time constant circuit according to the detected current. Has proposed a motor control device composed of

In the motor control device for this electric vacuum cleaner, the air flow rate Q is large when the brush is open and when the brush is close to the open state.
The current flowing through the motor 21 is large and the current detection circuit 27
A large current is detected at. A signal corresponding to this large current is given to the time constant circuit of the ignition pulse generating circuit 25,
Since the time constant is increased, the phase angle of the firing pulse output from the firing pulse generation circuit 25 to the firing circuit 26 is delayed, and the power supply to the motor 21 is suppressed. On the other hand, when the brush comes into close contact with the surface to be cleaned, the motor and the current control element 22
Since the current flowing through is small and the detection voltage is small, the time constant of the time constant circuit is also small, and the phase angle at which the ignition pulse is generated advances. Therefore, the energization current of the motor 21 becomes large, and the power supply is leveled.

[0005]

The conventional motor controller for the electric vacuum cleaner described above detects the electric current of the motor and controls the phase angle of the ignition pulse generating circuit in accordance with the electric current of the motor to supply the electric current. The power is smoothed, and during true suction,
Although more power is supplied, it controls the phase angle of the ignition pulse generation circuit, that is, the time constant of the time constant circuit included in the pulse generation circuit, so the concrete configuration of the time constant control circuit is complicated. Therefore, there are problems in that many circuit components are required, which hinders miniaturization and the product price cannot be reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a motor control device for an electric vacuum cleaner which can be downsized and realize low cost.

[0007]

A motor control device for an electric vacuum cleaner according to the present invention comprises a motor and a current control element connected in series, is connected to an AC power supply, and supplies a current to the motor when the current control element is turned on. A current detection circuit for detecting the current of the motor, which includes an ignition pulse generation circuit for generating an ignition pulse having a predetermined phase angle, and which turns on the current control element in response to the ignition pulse. , And a firing pulse level control circuit for controlling the firing pulse level according to the detected current.

In the motor controller for this electric vacuum cleaner, the ignition pulse generated by the ignition pulse generating circuit is applied to the gate of the current control element, and the current control element is turned on for a period corresponding to the phase angle of the ignition pulse. Drive the motor. When the motor is energized, its current is detected by the current detection circuit and applied to the firing pulse level control circuit. The ignition pulse level control circuit controls the level of the ignition pulse according to the detected current value and controls the energization time of the current control element to level the power supply.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a circuit diagram of a motor control device for an electric vacuum cleaner showing an embodiment of the present invention. In FIG. 1, a motor 2, a bidirectional three-terminal thyristor (hereinafter referred to as a thyristor) 3, and a series circuit of a resistor R11 are connected between AC power supply lines 7 and 8 to which a commercial AC power supply 1 is connected. Further, between the AC power supply line 7 and the connection point 9 of the cathode K of the thyristor 3 and the resistor R11,
A series circuit of resistors R7 and R8 is connected. Further, between the connection point of the resistors R7 and R8 and the gate G of the thyristor 3, the input terminals a and b of the full-wave rectifier circuit 4 including the diodes D2, D3, D4, and D5 are connected, and the full-wave rectifier circuit 4 is connected. The output terminals c and d are connected to the DC power supply lines 10 and 11 of the phase control circuit 5 as the ignition pulse generation circuit.

The series circuit of the resistor R1 of the phase control circuit 5 and the NPN type transistor Q1 is connected to the DC power supply lines 10 and 1.
1 and the base of the transistor Q1 is a resistor R3.
Connected to the collector of the PNP type transistor Q2 via the resistor R2 and the DC power supply line 1 via the resistor R2.
1 connected. In addition, the DC power supply lines 10 and 11
A series circuit of resistors R4 and R5 is connected between them. A series circuit of a resistor R6, a variable resistor VR1 and a capacitor C1 is connected between the DC power supply lines 10 and 11.
It constitutes a time constant circuit. A diode D1 is connected between the base of a transistor Q2 that constitutes the phase control circuit 5 and resistors R4 and R5, and the emitter of the transistor Q2 is connected to the joint of a variable resistor VR1 and a capacitor C2.

In FIG. 1, the circuit 6 surrounded by the alternate long and short dash line is
It is an ignition pulse level control circuit. The internal connection of the ignition pulse level control circuit 6 will be described. The collector of the PNP type transistor Q3 is the gate G of the thyristor 3.
And the emitter of the transistor Q3 is connected to the resistor R17.
Is connected to the AC power supply line 9 via. A resistor R18 is provided between the base of the transistor Q3 and the AC power supply line 9.
Is connected. Also, a PNP type transistor Q4
The collector of is connected to the AC power line 9,
The emitter is the gate G of the thyristor 3 via the resistor R20.
It is connected to the. A resistor R21 is connected between the base of the transistor Q4 and the gate G of the thyristor 3.

A resistor R12, a diode D6, a capacitor C2, a resistor R13 and a semi-variable resistor VR2 are sequentially connected in series from the AC power supply line 7 and are connected to the (-) input terminal of the arithmetic circuit IC1. The connection point between the capacitor C2 and the resistor R13 is connected to the power supply line 9. A resistor R14 is connected between the (+) input terminal of the arithmetic circuit IC1 and the AC power supply line 8. A resistor R15 is connected between the (−) input terminal and the output terminal of the arithmetic circuit IC1.

The connection point between the capacitor C2 and the resistor R13 is
It is connected to the (−) input terminal of the arithmetic circuit IC2 via the resistor R16. The output terminal of the arithmetic circuit IC1 is connected to the (+) input terminal of the arithmetic circuit IC2. The cathode of the diode D7 is connected to the (−) input terminal of the arithmetic circuit IC2, and the anode of the diode D7 is connected to the output terminal of the arithmetic circuit IC2.

The output terminal of the arithmetic circuit IC2 is connected to the anode of the diode D8 and the cathode of the diode D9 via the capacitor C3. The cathode of the diode D8 is connected to the connection point between the capacitor C2 and the resistor R13, and is also connected to one end of the capacitor C4. The anode of the diode D9 is connected to the other end of the capacitor C4, and is also connected to the base of the transistor Q3 via the resistor R19 and to the base of the transistor Q4 via the resistor R22.

The resistor R11 is for detecting a current flowing through the motor 2, and the resistor R11 may be a solid resistor connected between the printed wiring patterns or a part of the printed wiring patterns. It may be a foil plate to be formed. Next, the operation of the circuit of this embodiment will be described. When the AC power supply 1 is not connected to the circuit, no voltage is applied to the emitter of the transistor Q2, so that the transistor Q2 does not turn on. Therefore, no voltage is applied to the base of the transistor Q1 and the transistor Q2 is in the off state. As a result, no signal is given to the gate G of the thyristor 3 and it is not ignited, so that no drive current flows through the motor 2.

When the AC power supply 1 is connected, a DC voltage is applied between the DC power supply lines 10 and 11 via the rectifying circuit 4, the capacitor C2 is charged via the resistor R6 and the variable resistor VR1, and the emitter of the transistor Q2 is charged. As the voltage rises and exceeds the voltage of the base of the transistor Q2, which is divided by the resistors R4 and R5, the base current flows and turns on, and the electric charge charged in the capacitor C1 becomes the resistance R.
3. Discharge through R2 and oscillate a pulse. Charging / discharging of the capacitor C1 is repeated 1 to 10 or more times in the half cycle by changing the variable resistor VR1, and the first cross in the half cycle is generated in synchronization with the power supply frequency.
Therefore, the voltage of the resistor R2 at the cross is given to the base of the transistor Q1 to turn on the transistor Q1, and the pulse signal component is applied to the gate G of the thyristor 3 as an ignition pulse via the full-wave rectifier circuit 4. It is ignited and a phase-controlled voltage is applied to the motor 2. As a result, a current flows through the motor 2 according to the phase angle set by the variable resistor VR1.

When the current flowing through the motor 2 flows through the resistor R11, a voltage proportional to the current of the motor is generated across the resistor R11. The voltage across the resistor R11 is amplified by the arithmetic circuit IC1, but since the arithmetic circuit IC1 is operated by a single power source, only the + half-wave voltage is output. That is, a voltage corresponding to the current flowing through the motor 2 is output every half cycle. The arithmetic circuit IC2 has a buffer function, but need not be a buffer. Diode D
In step 7, temperature compensation is performed. That is, when the temperature rises, the V _{F of} the diode D7 drops, the feedback amount increases, and the output drops.

The capacitor C3, the diode D8, the capacitor C4, and the diode D9 are negatively charged by the pump-type voltage doubler rectifier circuit. This negative voltage is applied to the resistors R19 and R22.
Is added to the bases of the transistors Q3 and Q4 via. When the motor current increases, the control output, that is, the negative voltage, increases (-becomes deeper), the AC power supply is in the negative half cycle, the transistor Q3 is close to the ON state, and the positive half cycle is, the transistor Q4 is in the ON state. , The voltage applied to the gate G of the thyristor 3 decreases. In this way, when the motor current exceeds the predetermined value, the transistor Q
3, Q4 are alternately turned on according to the positive / negative of the AC power supply voltage. By this turning on, the voltage at the point b of the full-wave rectifier circuit 4, that is, the gate applied voltage of the thyristor 3 becomes low.

Therefore, the thyristor 3 originally does not reach the gate trigger voltage in the firing phase of the thyristor set by the time constant circuit, but only in the power supply phase slightly delayed from the set phase (that is, high power supply voltage). Will not be ignited, and the current value will be smaller than the energizing current of the motor 2 in the set phase. The threshold value of how much current value is detected to start the decrease of the current value is set by adjusting the semi-variable resistor VR2 on the input side of the arithmetic circuit IC1.

With such an operation, when the vacuum cleaner, which has been set to the optimum input for the initial purpose, that is, the cleaning condition of the floor to be cleaned, lifts the suction nozzle away from the floor and lifts it into the air, etc. When the air intake amount becomes excessively large and the input becomes excessively large, the increasing current value is detected, and the effect of reducing unnecessary power consumption in order to reduce the excessive input increase is obtained.

From this state, when the nozzle is again lowered and brought into close contact with the floor surface to be cleaned or the like, the degree of vacuum increases,
The amount of sucked air decreases and the input current of the motor 2 also starts to decrease. In this case, the voltage drop across the resistor R11 also decreases, the voltage doubler output also decreases, and the voltage across the gate resistors R18 and R21 of the transistors Q3 and Q4 also decreases (-becomes shallower).
Then, the transistors Q3 and Q4 are also opened (OFF state),
The ignition pulse voltage from the phase control circuit 5 is not attenuated as it is and can be ignited to the gate of the thyristor 3.
Since it is applied as a trigger voltage, the thyristor 3 fires at the set phase and restores the initial set input. Although the output voltage of the diode D9 is negative in this embodiment, the polarity of the diode D9 is reversed to derive a positive voltage, while the transistors Q3 and Q4 are NP.
By using the N type, the same power control as in the case of FIG. 1 can be performed.

FIG. 2 is a circuit diagram of a motor control device for an electric vacuum cleaner showing another embodiment of the present invention. In FIG. 2, a commercial AC power supply 1 is connected by AC power supply lines 7 and 8, a series circuit of a motor 2, a thyristor 3 and a resistor R11, a full wave rectification circuit 4 of diodes D2, D3, D4 and D5 and a resistor R23. Are connected in parallel to the series circuit. The output DC voltage of the full-wave rectification circuit 4 is the phase control circuit 5
Is supplied as the DC power supply voltage of.

DC power supply lines 10 and 1 of the phase control circuit 5
Between 1, the resistor R24, the diode D10, the resistor R25
And a series circuit of a resistor R30 and UJT13,
A series circuit of diodes D11 and D12 is connected in parallel. Also, the diode D10 and the resistor R2
Between the connection point of 5 and the DC power supply line 11, resistors R26 and R
A series circuit of 27 and a series circuit of the variable resistor VR3 and the capacitor C5 are connected in parallel with each other. Resistors R26 and R
The connection point of 27 is connected to the gate of UJT12, the connection point of variable resistor VR3 and capacitor C5 is connected to the anode of UJT12, and the cathode of UJT12 is connected to resistor R.
It is connected to the gate of UJT 13 via 28. U
The gate of JT12 is connected to the DC power supply line 11 by a resistor R27. Also, the diodes D11 and D1
The connection point of 2 is connected to the gate G of the thyristor 3. The phase control circuit 5 here uses the transistors Q1 and Q2 in the case of FIG.
3 is used, the firing pulse generation operation is the same.

The firing pulse level control circuit 6 has the same basic configuration as that of FIG. In FIG. 2, the connection point of the thyristor 3 and the resistor R11 for current detection, that is, the power supply line 9 is connected to the (+) of the arithmetic circuit IC1 via the resistor R14.
Also in the circuit of this embodiment connected to the input end, when a large current flows through the motor 2, a large negative voltage is derived as the output of the ignition pulse level control circuit 6,
In response to this, the transistor Q3 is turned on in the negative half cycle of the AC power supply, and the transistor Q4 is turned on in the positive half cycle, and the firing pulse level is lowered in both cases, so that the firing phase angle becomes large and the thyristor 2 The ignition time is shortened and the electric energy of the motor 2 is reduced.

[0025]

According to the present invention, the motor current is controlled in the one in which the on / off of the current control element connected in series to the motor is controlled by the ignition pulse from the ignition pulse generating circuit composed of the semiconductor element. It detects and adjusts the firing pulse level according to the current to reduce the power supply when the nozzle is opened, and conversely, the power supply can be increased when the floor surface is in contact.
The function of efficient cleaning can be realized with a simple structure at low cost, and the size can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a motor control device for an electric vacuum cleaner showing an example of an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a motor control device for an electric vacuum cleaner showing another example of the embodiment of the present invention.

FIG. 3 is a schematic block diagram illustrating a motor control device of a conventional vacuum cleaner.

[Explanation of symbols]

 2 Motor 3 Bidirectional 3-terminal thyristor 6 Firing pulse level control circuit R11 Current detection resistor Q3, Q4 Transistor

Claims (4)

[Claims] 1. A circuit comprising a motor and a current control element connected in series, connected to an AC power supply, and energizing the motor when the current control element is turned on, and an ignition pulse generation for generating an ignition pulse having a predetermined phase angle. A motor control device for an electric vacuum cleaner which receives the ignition pulse and turns on the current control element, the current detection circuit detecting a current of the motor, and an ignition pulse according to the detected current. A motor control device for an electric vacuum cleaner, comprising: an ignition pulse level control circuit for controlling a level. 2. The motor controller for a vacuum cleaner according to claim 1, wherein the current detection circuit is composed of a resistor connected in series to the motor. 3. The motor control device for the electric vacuum cleaner according to claim 2, wherein the resistor is formed of a foil plate forming a printed circuit. 4. A circuit for deriving a voltage according to a detected current and a circuit for deriving a voltage according to a detected current, in response to the derived voltage being equal to or more than a predetermined value, during a positive half cycle of an AC power supply. A first switching element that is turned on to lower the voltage to the gate of the current control element, and turned on during the negative half cycle of the AC power supply in response to the derived voltage being equal to or greater than a predetermined value, and the current control element The motor control device for the electric vacuum cleaner according to claim 1, 2 or 3, further comprising a second switching element that lowers the voltage to the gate of the electric vacuum cleaner.