JP3039558B2 - Electric vacuum cleaner - Google Patents

Description

The present invention relates to a vacuum cleaner, and more particularly, to an improvement of a vacuum cleaner using a brushless DC motor driven by a chopper control type inverter.

[Conventional technology]

An example of a vacuum cleaner using a brushless DC motor driven by a chopper control type inverter is disclosed in
This type of vacuum cleaner is described in Japanese Patent Application Laid-Open No. -214219, in which the rotation speed of a brushless DC motor is controlled to a predetermined rotation speed to obtain a predetermined suction force.

[Problems to be solved by the invention]

However, in the vacuum cleaner using a brushless DC motor driven by a chopper control type inverter as described above, conventionally, protection during overload operation, and prevention of high-speed rotation due to abnormal rotation command value of the control device, etc. have been particularly recognized. The fact is that they do not.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum cleaner using a chopper control type inverter driven brushless DC motor, to easily prevent overload operation without using a special protection device, and to further prevent a high speed due to a rotation command value abnormality of the control device. An object of the present invention is to provide an improved vacuum cleaner of this kind which can prevent rotation.

[Means for solving the problem]

The object is to incorporate a brushless DC motor controlling the number of rotations by a chopper control type inverter device into an electric blower, and in the electric vacuum cleaner having the electric blower in a cleaner body, the brushless DC motor has a suction air volume of a suction port. The brushless DC motor is equilibrated with the power supply voltage when the air flow is equal to or greater than the air flow in the non-cleaning state when the brushless DC motor is lifted, and the brushless DC motor is operated at a chopper control duty ratio of 100%. Is achieved.

[Action]

By the way, a brushless DC motor is a synchronous motor using a permanent magnet as a field, and an inverter device controls a rotation speed by changing a conduction ratio so as to reach a specified rotation speed according to a load state. On the other hand, when the load is increased and the flow rate is set to 100%, in a state where the rotation does not rise to the designated rotation, the rotation speed turns at a value balanced with the load torque. At this time, if the motor specifications are determined such that the back electromotive force generated in the armature winding becomes equal to the power supply voltage, even if the load torque is higher than that, only the rotation speed will decrease, and Input does not increase significantly. That is, the current increases by an amount corresponding to the decrease in the back electromotive voltage corresponding to the decrease in the number of rotations, and the input increases. However, the increase in the input is suppressed to a predetermined range in a saturated manner.
Even when a large amount of air flows into the electric blower to increase the load as in the case of non-cleaning, a large increase in input can be prevented. Further, even when a high-speed rotation command value is issued due to an abnormality in the control device, it is possible to automatically prevent the motor rotation speed from rising to a predetermined rotation speed or more.

〔Example〕

Hereinafter, the present invention will be described with reference to FIG. 2 to FIG.
FIG. 1 is an explanatory view of the overall configuration of a speed control device comprising a brushless DC motor 6 and an inverter control device 1, and FIGS. 2 and 3 show a brushless DC motor as a driving source. FIG. 4 is a performance characteristic diagram of a vacuum cleaner of the present invention having an input restriction function.

In FIG. 1 showing the overall configuration of a speed controller for a vacuum cleaner, an inverter controller 1 obtains a DC voltage Ed from an AC power supply 2 via a rectifier circuit 3 and a smoothing capacitor 4 and supplies the DC voltage Ed to an inverter 5.

The inverter 5, the transistor Tr ₁ is 120 degree conduction inverter which is composed to Tr ₆ and the reflux diode D ₁ to D ₆ Tokyo, the AC output voltage, the DC voltage positive potential side transistors TR ₁ to Tr ₃ of Ed Is controlled by performing pulse width modulation and performing a chopping operation.

Further, low resistance between the common anode terminal of the common emitter terminal of the transistor TR ₄ to Tr ₆ and the reflux diode D ₄ ~D ₆ R ₁
Is connected.

The brushless DC motor 6 includes a rotor 6-1 having a two-pole permanent magnet as a field, and a stator having an armature winding 6-2 inserted therein, and a winding flowing through the armature winding 6-2. The current is
Since flow in the resistor resistance R _1, it is possible to detect the load current I _D of O connexion the motor 6 to the voltage drop of the low-resistance R _1.

Brushless control circuit for controlling the speed of the DC motor 6, the microcomputer 7, the magnetic pole position detecting circuit 9 which the magnetic pole position of the rotor 6-1 is detected by receiving the output from the Hall element 8, the voltage drop across the low-resistance R ₁ A current detection circuit 10 for detecting the value of the load current _ID , a base driver 11 for driving the transistors TR _{1 to} TR ₆ , and a speed command circuit 12 for transmitting a reference speed to the microcomputer 7.

The magnetic pole position detection circuit 9 is a circuit that receives an output from the Hall element 8 and forms a position detection signal 9S corresponding to the rotor position. Then, using the position detection signal 9S, the rotation speed of the brushless DC motor 6 is calculated and obtained in the micro computer 7.

Current detection circuit 10 receives the voltage drop across the resistance R ₁ detects the load current I _D, forming a current detection signal 10S by an A / D converter (not shown).

The microcomputer 7 comprises a CPU, a ROM, a RAM, and the like, and is connected by an address bus, a data bus, and a control bus (not shown), respectively.

The ROM stores various processing programs required for driving the brushless DC motor 6, such as programs for speed calculation, command fetching, speed control, and the like.

On the other hand, the RAM includes a storage unit for reading and writing various data necessary for executing the various processing programs.

Transistor TR ₁ to Tr ₆ receives a firing signal 7S from the microcomputer 7, is driven by the base driver 11.

The voltage command circuit 13 forms a later-described chopper signal. That is, in the brushless DC motor 6, the winding current flowing through the armature winding 6-2 corresponds to the output torque of the motor 6, and by controlling the winding current for each rotation position, the output torque can be continuously controlled. Becomes possible.

FIG. 2 shows the performance characteristics of the vacuum cleaner using the brushless DC motor 6 as a driving source, as described above, wherein the horizontal axis represents the airflow Q of the wind passing through the vacuum cleaner, and the vertical axis represents the electric current. negative pressure pressure H that represents the suction force of the vacuum cleaner, a representation of the rotational speed N and the input Wi motors, the minimum operating point from the maximum operating point Q ₁
Range of Q ₂ is the operating range of the vacuum cleaner. Then, Q ₁ near maximum power point corresponds to a state in which the suction port is away from the surface to be cleaned, when this requires maximum power. Further, Q ₂ near the minimum operating point corresponds to a state in which the suction port is in close contact with the floor surface,
This is the minimum power.

By the way, as shown in FIG. 3, the optimum suction characteristics of the electric vacuum cleaner are determined by appropriately selecting each curve corresponding to a plurality of rotation speeds as a combination of the basic characteristics shown in FIG. Thus, it can be realized freely.

However, from the viewpoint of the constraint condition of the input Wi, the practical upper limit value,
That is, to use the allowable input limit W ₁ or more ranges is not preferable. For example, if you select the rotational speed N ₁ at flow rate Q ₃ points, input Wi is would exceed the allowable input limit W _1, thereby summer and overload conditions.

Here, if the input Wi has come allowable input limit W ₁ or more ranges, the processing program of the control device, if to reduce the rotational speed command value to the N ₂ and N _3, overload operation Can be avoided, but on the other hand, there is a disadvantage that the processing program of the control device becomes complicated. It is also conceivable to attach a special overload monitoring device, but this has the disadvantage that the cost increases and the device becomes large.

The present invention, as the actual range of use of the cleaner, by paying attention to it is not necessary to issue a suction force than necessary in the range of airflow Q ₁ from the air volume Q ₃ is a non-cleaning state of lifting the mouthpiece, near this range In this configuration, the input is automatically restricted.

That is, the armature winding 6-2 includes the rotor 6-1.
While the counter electromotive force corresponding to a rotation of the occurs, as shown in FIG. 4, the air volume of the load while the power voltage and the counter electromotive voltage is balanced duty ratio becomes 100% so that the air flow rate Q _4, Rotor 6
By setting the number of turns of the first Magunetsuto magnetomotive force and armature windings 6-2, in large airflow side than Q _4, it was prepared in load increase connexion, gradually lower than the rotational speed N ₄ are command value rpm and, an increase in the input, it only incrementally saturated manner, it is possible to automatically keep a predetermined value of W ₁ or less is an allowable input limit.

As described above, regardless of the speed command value, the input increase can be automatically restricted on the large load side where the flow rate of the chopper control exceeds 100%.

Further, even when a high-speed command value is output due to an abnormality of the speed command circuit 12 or the microcomputer 7,
Abnormal high speed operation can be automatically prevented on the brushless DC motor 6 side which is an electric machine (hardware).

〔The invention's effect〕

The present invention is as described above.According to the present invention, in a vacuum cleaner using a chopper control type inverter-driven brushless DC motor, it is possible to easily prevent overload operation without using a special protection device, and furthermore, It is possible to provide an improved vacuum cleaner of this type that can prevent high-speed rotation due to a rotation command value abnormality of the control device.

Since the above control does not rely on the control processing program to avoid overload operation, even if the microcomputer should fail, it is very advantageous in terms of safety.

In addition, in the vicinity of the allowable input upper limit, which is a region where the load becomes large, the flow rate is close to 100% and the chopping control is not performed or is small, and the harmonic component generated by the intermittent operation is small. The system efficiency including the DC motor is in the best condition. That is, high efficiency can be achieved on the high load side, and for example, an increase in heat generation can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the overall configuration of a speed control device including a brushless DC motor 6 and an inverter control device 1 according to an embodiment of the present invention. FIGS. 2 and 3 show a brushless DC motor as a drive source. FIG. 4 is a performance characteristic diagram of the used vacuum cleaner, and FIG. 4 is a performance characteristic diagram of the vacuum cleaner of the present invention having an input restriction function. 1 ... Inverter control device, 6 ... Brushless DC motor.

Continuing from the front page (72) Inventor Hisanori Toshima 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Plant, Hitachi, Ltd. (72) Mitsuhisa Kawamata 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Stock (72) Inventor Haruo Oharaki 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. (72) Inventor Kazuo Tahara 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Hitachi Research, Ltd. In-house (72) Inventor Takeshi Abe 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Research Laboratory, Inc. (72) Inventor Toshiyuki Yasushima 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture, Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. (72) Inventor Tsunehiro Endo 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Kunio Miyashita 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside Taga Plant, Hitachi, Ltd. (56) References Special Showa 60- 125192 (JP, A) JP-A-61-76093 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 6/08

Claims (1)

(57) [Claims] 1. A vacuum cleaner in which a brushless DC motor whose rotation speed is controlled by a chopper control type inverter device is incorporated in an electric blower, and the electric blower is provided in a cleaner main body. The brushless DC motor is provided with a brushless DC motor in which the back electromotive voltage of the brushless DC motor is balanced with the power supply voltage when the air flow is equal to or higher than the non-cleaning state in which the suction port is lifted, and the value is such that the brushless DC motor operates at a chopper control flow rate of 100%. An electric vacuum cleaner characterized by the above.