JP2855853B2 - Electric vacuum cleaner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum cleaner equipped with a fan motor control device suitable for a vacuum cleaner using a fan motor as a drive source.

[0002]

2. Description of the Related Art Conventionally, in an electric vacuum cleaner, an AC commutator motor is used as a driving source, and a voltage applied to the AC commutator motor by a triac is combined with a triac which is a control element and a pressure sensor or an airflow sensor. There are known vacuum cleaners which adjust the power and control the power according to the surface to be cleaned or according to the value detected by a pressure sensor or an air flow sensor.

[0003]

In the above prior art, the factors indicating the load state of the fan motor, that is, the air volume, are directly detected by an air volume sensor, or the relationship between the static pressure and the air volume is tabulated in advance and the static pressure sensor is used. And control the rotational speed. For this reason, the former has a problem of an increase in price and a volume due to the attachment of the sensor, and the latter has a problem that the table data becomes enormous when trying to obtain the air volume in a wide range with high accuracy. SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum cleaner capable of detecting various factors indicating a load state, that is, an air volume without an air volume sensor, and thereby performing optimal operation.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is characterized by a filter for collecting dust, a variable speed fan motor for generating dust suction force, and a fan motor. Load current detection means for detecting a load current, rotation speed detection means for detecting the rotation speed of the fan motor, a static pressure sensor for detecting the static pressure of the cleaner,
A controller that controls the fan motor based on the detected load current, the rotation speed, and the static pressure, wherein the control unit includes a load current, a rotation speed, and a rotation speed of the fan motor. An air flow is calculated from the static pressure of the vacuum cleaner in accordance with a previously stored calculation rule, a speed command for the fan motor corresponding to the calculated air flow is created, and the rotation speed of the fan motor detected by the rotation speed detection unit is calculated. A current command value is created from a deviation between a speed and a speed command of the fan motor, and the fan motor is controlled such that the current command value matches a load current detected by the load current detection unit. .

[0005]

[0006]

The air flow is calculated from the load current, the rotation speed and the pressure of the fan motor, and the speed command of the fan motor is determined based on the result, so that an optimum suction force according to the load condition can be obtained without an air flow sensor. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic configuration of a fan motor according to an embodiment of the present invention. The fan motor is
The control device 40 comprises a variable speed motor 38 and a fan 39.
And the signal 41S from the speed detector 41 and the current detector 42
And the signal 43S from the pressure sensor 43 are received as a signal 44S from the pressure detector 44 to detect the rotation speed and the load current. The control device that controls the speed of the variable speed motor 38 calculates various factors indicating the load state, for example, the air volume Q, from the rotation speed, the load current, and the pressure, and operates the fan motor based on the calculation result.

The fan motor may be used for a fan, a cooling blower, a vacuum cleaner, or the like. In the present embodiment, a vacuum cleaner whose operating state changes according to a load state will be described as an example.

As a variable speed motor used for a fan motor of a vacuum cleaner, an AC integer motor, a phase control motor, an inverter driven induction motor, a reluctance motor, a brushless motor, etc. Among them, an example will be described in which a brushless motor having a long life and good control response without using a brush accompanied by mechanical sliding is used as a fan motor.

Further, the present invention will be described by taking, as an example, various factors indicating the load state of the fan motor, the air flow indicating the load state of the vacuum cleaner. FIG. 2 shows a schematic configuration of the vacuum cleaner,
FIG. 3 is a block diagram showing a schematic configuration of the control circuit, and FIG. 4 shows an overall configuration of the control circuit.

In FIG. 1, reference numeral 31 denotes a vacuum cleaner main body.
Reference numeral 6 denotes an inverter control device for operating the brushless motor 17 at a variable speed. 29 is an AC power source, rectifies the power source 29 by the rectifier circuit 21, the DC voltage E _d is supplied to the inverter circuit 20 is smoothed by the capacitor 22. The inverter circuit 20 includes transistors TR _{1 to} TR ₆
And a 120-degree conduction type inverter composed of freewheeling diodes D _{1 to} D ₆ connected in parallel to the respective transistors. The transistor TR ₁ to Tr ₃ positive arm, the transistor TR ₄ to Tr ₆ constitute a negative arm,
Each conduction period of the negative arms is pulse width modulated (PWM) at an electrical angle of 120 degrees. R ₁ is connected relatively low resistance between the negative side of the emitter side and the capacitor 22 of the transistor TR ₄ to Tr ₆ that constitutes the negative arm.

The brushless motor 17 comprises a rotor R composed of two permanent magnets and armature windings U, V, W.
Load current I _DC flowing through the windings U, V, and W can be detected as a voltage drop across the resistor R _1.

The speed control circuit of the brushless motor 17
Magnetic pole position detection circuit 18 for detecting the magnetic pole position of the rotor R in the Hall element PS etc., the voltage drop of current amplifier 23 (resistor R ₁ that amplifies the detected value of the load current I _DC mentioned above is a DC current, brushless motor is different from the load current 17, which comprises a voltage drop of the resistor R ₁ amplifies and simulates the load current of the brushless motor 17 by the discharge circuit with peak poled circuit), the transistor TR ₁ ~
It is mainly composed of a base driver 15 for driving the TR ₆ and a microcomputer 19 for driving the base driver 15 based on a magnetic pole position detection signal 18S obtained from the magnetic pole position detection circuit 18. A static pressure amplifier 33 amplifies a detection value of a static pressure sensor 32 for detecting a pressure (static pressure) of the vacuum cleaner.
Process at step 9. An operation switch 30 is operated by an actual user.

In the above, the magnetic pole position detecting circuit 18 receives the signal from the Hall element PS and generates a magnetic pole position detecting signal 18S of the rotor R. The magnetic pole position detection signal 18S is used not only for switching the current of the armature windings U, V, W, but also for detecting the rotation speed.

The microcomputer 19 obtains the rotation speed by counting the number of the magnetic pole position detection signals 18S within a certain sampling.

The microcomputer 19 includes a central processing unit (CPU) 19-1, a read-only memory (ROM) 19-2, and a random access memory (RAM) 19-3. And a data bus and a control bus. And RO
M19-2 includes programs necessary for driving the brushless motor 17, such as a speed calculation process, an operation command fetch process, a speed control process (ASR), a current control process (ACR), and a current detection process. Is stored.

On the other hand, the RAM 19-3 has a ROM 19-2.
It is used to read and write various necessary external data when executing various programs stored in the.

The transistors TR _{1 to} TR ₆ are respectively driven by the base driver 15 in accordance with the ignition signal 19S processed and generated by the microcomputer 19.

In this type of brushless motor 17, the current flowing through the armature windings U, V, W corresponds to the output torque of the motor, and conversely, the output torque can be varied by changing the applied current. That is, the output torque of the motor can be continuously and arbitrarily changed by adjusting the applied current, and the rotation speed of the motor can be arbitrarily changed by changing the drive frequency of the inverter.

The vacuum cleaner of the present invention uses such a brushless motor 17. FIG. 5 shows QH characteristics of a vacuum cleaner using a brushless motor, in which the horizontal axis represents airflow Q, and the vertical axis represents static pressure H and load torque T of a fan (fan of an electric blower). is there.

In FIG. 5, the QH characteristic of the vacuum cleaner is such that when the rotation speed of the motor is constant, the static pressure H is large when the air volume Q is small, and the static pressure H is small when the air volume Q is large. Becomes
Further, the load torque T of the fan has a square curve with respect to the air volume Q, and this load torque T also varies depending on the state of the suction port (change of the inflow area of the wind) although not shown.

In the QH characteristics of such a vacuum cleaner, the brushless motor 1 can be used without using an air flow sensor.
In order to calculate the air volume from the load state of 7, various measures are required.

First, the output P (W) of the brushless motor is expressed by the following equation.

[0025]

## EQU1 ## P = 1.027 × N × T (W)

Here, N is a rotation speed (rpm), and T is a torque (Kg-m). From the above equation 1,

[0027]

(Equation 2)

## EQU1 ## In Equation 2, the output P is

[0029]

## EQU3 ## P = E ₀ · I

[0030]

E ₀ = K ₀ · N

Is as follows. Here, E ₀ is the induced voltage (V),
K ₀ is the induced voltage coefficient, and I is the load current (A). From the above equation 2, the above equation 3, and the above equation 4,

[0032]

(Equation 5)

## EQU1 ## That is, the torque T is proportional to the motor current I.

On the similar side of a general fluid, the following relationship is known.

[0035]

[Expression 6] L∝N ³ · D ⁵

[0036]

[Expression 7] Q∝ND ³

[0037]

H８N ² · D ²

Here, L is the axial input (W) of the fan, Q is the air volume (m ³ / min), H is the static pressure (mmAq), and N is the rotational speed (rp).
m) and D indicate the diameter (mm) of the impeller. Since the fan and the motor are directly connected, it is considered that the axial input L and the rotational speed N of the fan are equal to the output P and the rotational speed of the motor. From equation (8), it can be transformed into the following equation.

[0039]

[Expression 9] P∝Q · H

Here, the output P of the motor is obtained from the above equation (3) and the above equation (4).

[0041]

P = K ₀ · I · N

Therefore, Equation 9 is obtained from Equation 10 above.

[0043]

[Equation 11]

Can be expressed as follows. Further, the above equation (11) is based on the equation (8) and the equation (9), the air volume Q is

[0045]

(Equation 12)

Can be expressed as Here, many error factors such as blower efficiency, motor efficiency, air leakage from the cleaner body, and a change in unit weight of air due to temperature are considered, but are ignored for simplicity.

FIG. 6 shows typical operation patterns (A pattern, B pattern) of the vacuum cleaner. In Q-H characteristics of FIG, A pattern performs Q _A constant control in large volume side, below the air volume Q _A are those performing H _A constant control.
B pattern performs Q _B constant control in airflow Q _A smaller air volume Q _B, below the air volume Q _B is intended to perform a constant speed constant control rotational speed N _B.

The pattern A is based on the assumption that the surface to be cleaned is deflected. When the air volume is larger than the large air volume Q _A , the rotation speed is reduced and the motor input is reduced to keep the volume Q _A constant. In addition, Q _A
In the following, the static pressure H is set so as not to damage the folding surface.
_A Constant control.

[0049] B pattern intended surface to be cleaned assuming a free sputum performs air volume Q _B constant control, the rotational speed reaches the maximum N _B, and the air volume is the rotational speed N _B constant control in the following Q _B And to get the maximum power as a vacuum cleaner.

Next, specific control means will be described with reference to FIGS.

[0051] If the actual operator operates the operation switch 30, first, the microcomputer 19 as a process 1, by performing the operation instruction acquisition process and activation process to drive the brushless motor 17 to the rotational speed N ₁ defined . The changeover switch S ₁ selects the speed command N ₁ at the time of start-up, and when the driving is completed, the output N of the AQR and AHR in the process 7
Select _CMD .

[0052] When the speed command N ₁ is determined at startup, the microcomputer 19 performs an arc signal generation processing terms of processing 6 receives the magnetic pole position detection signal 18S from the magnetic pole position detecting circuit 18, the transistor TR ₁ to Tr ₆ Determine the firing element. Then, the actual speed N of the brushless motor 17 is calculated by performing the speed calculation process of process 2, and the load current I of the brushless motor 17 is detected by receiving the signal 23S from the current amplifier 23 in the current detection process of process 3. .

The ASR in the process 4 is the speed command N _* and the actual speed N
Current command I _CMD from the deviation ε _N from
R calculates the voltage command V _* from the deviation epsilon _I of the load current I and the current command I _CMD.

The firing signal generation processing of processing 6 is performed by the voltage command V _*.
And the magnetic pole position detection signal 18S, the transistor TR ₁
And determines the elements that ignition of to Tr _6, the applied voltage to output the PWM was firing signal 19S for the variable.

When the brushless motor 17 has a specified rotation speed N
Upon reaching the _1, the changeover switch S ₁ is processing 7 of the AQR, A
It switched to the output signal N _CMD of HR.

Processing 7 AQR (air volume controller), AHR
The (static pressure regulator) outputs a speed command N _CMD from the actual speed N and the load current I so that a predetermined air volume Q and a static pressure H are obtained, for example, turns A and B in FIG. .

The brushless motor 17 performs processes 4 and 4 so that the rotation speed N is not an external command but an internal command _NCMD .
5, the voltage command V _* is determined via the ASR and ACR,
Controlled.

As described above, in the present embodiment, a brushless motor is used as a drive source of the vacuum cleaner, and the air volume Q is determined from the load current I, the rotation speed N, and the static pressure H of the motor without using an air volume sensor. Calculated by calculation, constant air volume control (AQR), constant static pressure control (AHR) according to operation pattern
By driving, the power of the vacuum cleaner can be optimally controlled.

In this embodiment, the air volume Q is calculated from the load current, the rotation speed and the static pressure of the brushless motor.
It can be obtained by calculating the ratio between the current command and the rotation speed.

The experimental data of FIG. 7 shows the operation of the vacuum cleaner in terms of the air volume and the static pressure. The air volume Q can be obtained from the ratio of the product of the current command and the rotation speed to the static pressure. Based on the above, stable air volume constant control is possible.

The experimental data shown in FIG. 8 shows the operation of the vacuum cleaner in terms of air volume and static pressure. The data obtained by obtaining the air volume Q from the ratio between the current command I and the rotation speed N (I / N) and the current command The one that obtains the air volume Q from the ratio of the product of I and the rotation speed N and the static pressure H (I ·
Comparing (N / H), the system based on I / N moves in a direction in which the air volume decreases as the static pressure increases. Conversely, the method using I / N / H moves so that the air volume increases when the static pressure increases. The following equation is derived from the relationship between the two, that is, Equation 11, and Equation 12.

[0062]

(Equation 13)

According to the above-described method of taking the average value of Expression 13,
It is possible to calculate the air volume with higher accuracy. In the present embodiment, an average value of Equation 11 and Equation 12 is taken, but a ratio may be taken.

Further, the calculated values of the air volume Q and the static pressure H are
In the present embodiment, the motor is used for motor control, but may be used to indicate the load state of the vacuum cleaner.

Further, in this embodiment, an example in which a brushless motor is used as the fan motor has been described, but it goes without saying that an AC commutator motor may be used.

[0066]

According to the present invention, the air flow is calculated indirectly from the load current, the rotation speed and the static pressure of the fan motor without using the air flow sensor, and the rotation speed of the fan motor is adjusted based on the calculation result. As a result, it is possible to provide an electric vacuum cleaner that can be operated with optimal power while suppressing an increase in the price and size of the vacuum cleaner.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a fan motor showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a vacuum cleaner showing one embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a control circuit of a brushless motor for a vacuum cleaner according to an embodiment of the present invention.

FIG. 4 is an overall configuration diagram of a control circuit of a brushless motor for a vacuum cleaner according to an embodiment of the present invention.

FIG. 5 is a QH characteristic diagram of the vacuum cleaner.

FIG. 6 is a view showing a typical operation pattern of the electric vacuum cleaner.

FIG. 7 is experimental data showing the relationship between air flow and current command × rotation speed / static pressure.

FIG. 8 is experimental data showing the relationship between the air volume and (current command / rotation speed + current command × rotation speed / static pressure) / 2.

[Explanation of symbols]

15: Base driver, 16: Inverter, 17: Brushless motor, 18: Magnetic pole position detecting circuit, 19: Microcomputer, 23: Current amplifier, 30: Operation switch, 38: Variable speed motor, 39: Fan, 40: Control device .

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsunehiro Endo 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Hisao Suga 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Taga Plant (72) Inventor Mitsuhisa Kawamata 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Taga Plant (72) Inventor Fumio Joraku 1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture No. 1 Inside the Taga Plant of Hitachi, Ltd. (72) Inventor Yoshitaro Ishii 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Plant of Hitachi, Ltd. (56) References JP-A-4-4788 (JP, A JP-A-63-95882 (JP, A) JP-A-62-152389 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A47L 9/28 H02P 5 / 00-6/24 F04D 27/00

Claims (1)

(57) [Claims] 1. A filter for collecting dust, a variable speed fan motor for generating a dust suction force, load current detecting means for detecting a load current of the fan motor, and detecting a rotation speed of the fan motor. A vacuum cleaner including: a rotation speed detection unit; a static pressure sensor for detecting a static pressure of the cleaner; and a control unit for controlling the fan motor based on the detected load current, the rotation speed, and the static pressure. The control means calculates an air volume from a load current, a rotation speed of the fan motor, and a static pressure of the cleaner according to a previously stored calculation rule, and controls the fan motor corresponding to the calculated air volume. A speed command is created, and a current command value is created from a deviation between the fan motor rotation speed detected by the rotation speed detection means and the fan motor speed command. An electric vacuum cleaner wherein the fan motor is controlled so that the load current detected by the load current detecting means coincides with the load current.