JP2001258805A - Inverter device and vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized, lightweight vacuum cleaner. SOLUTION: An inverter circuit 38 is connected to a rectifying circuit 32 connected to the output of a commercial power source 31 to outputs a pulsating voltage. An induction type electric motor 45 is further connected thereto set the output frequency of the inverter circuit 38 larger than the pulsating ripple frequency of the pulsating voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to general households and factories,
The present invention relates to an inverter device such as an air conditioner, a household appliance, a rotary cooker, and an electric vacuum cleaner used in a store, an office, and the like.

[0002]

2. Description of the Related Art FIG. 6 shows a circuit diagram of a vacuum cleaner using a conventional inverter device.

FIG. 6 shows a commercial power supply 1 of 100 V and 60 Hz, a rectifier circuit 2 connected to the commercial power supply 1, and a smoothing circuit 3 connected to an output of the rectifier circuit 2.

The rectifier circuit 2 is of a full-wave type, and is constituted by diodes 4, 5, 6, and 7, and a smoothing circuit 3
Is composed of a choke coil 8 and an electrolytic capacitor 9. The choke coil 8 is formed by winding a copper wire around an iron core having a gap formed by stacking silicon steel plates.
= 3 mH and the capacitor 9
Has a capacitance of C = 4700 microfarads.

The inverter circuit 10 operates by receiving the DC voltage V1 from the smoothing circuit 3, and is constituted by switching elements 11, 12, 13, 14, 15, and 16.

The motor 17 is connected to the output of the inverter circuit 10 and has an inner rotor structure.
8, 19, and 20 and a rotor 21 positioned inside the rotor 21 and rotatably provided by a bearing or the like. The rotor 21 uses a permanent magnet,
The torque is generated by the interaction with the current flowing through 9, 20.

Further, the electric motor 17 is provided with Hall ICs 22, 2
3 and 24, which detect the position of the magnetic pole of the rotor 21 and output a position detection signal.

The control circuit 25 receives a position detection signal from the electric motor 17 and receives the switching elements 11, 12, 13, 1
The drive current is supplied from the inverter circuit 10 to the electric motor 17 by controlling ON / OFF of the switches 4, 15, and 16 in order.

With the above configuration, the inverter device 26
The impeller-type fan 27 is connected to the rotor 21 of the electric motor 17 and operates as a vacuum cleaner.

FIG. 7A shows an input voltage V1 of an inverter circuit 10 of a conventional vacuum cleaner, and FIG.
5 shows a waveform of an input current Iin from the first embodiment.

The smoothing circuit 3 is a full-wave rectified rectifier circuit 2.
Output has a voltage pulsation component (a ripple component).

The frequency of the pulsation (pulsation ripple frequency) is
The frequency is twice the frequency of the commercial power supply 1, and when the commercial power supply 1 is 60 Hz, the frequency is 120 Hz.

In the prior art, since the choke coil 8 and the capacitor 9 are provided, the inverter circuit 10
The ripple voltage of the input voltage V1 is considerably absorbed, and the peak-to-peak is suppressed to 10 volts.

[0014]

In such a conventional technique, the choke coil 8 and the capacitor 9 constituting the smoothing circuit 3 are large in weight, volume and cost, so that the weight, volume and cost of the apparatus are large. Has a first problem that the size of the document becomes considerably large.

Further, the waveform of the current Iin supplied from the commercial power supply 1 to the apparatus is considerably deviated from the voltage waveform (sine wave) of the commercial power supply 1, and the peak current is large and the power factor is low. There is a second problem that the loss of the system becomes large and the utilization factor of the distribution equipment becomes low.

In particular, since the motor 17 using a permanent magnet is used, the induced electromotive force corresponding to the speed is generated by the stator winding 1.
8, 19, and 20, it is necessary to reduce the ripple voltage V1 in order to effectively use the torque of the electric motor 17 even near the zero volt point of the commercial power supply 1.

The first problem and the second problem are that the rectifier circuit 2 has a structure other than the full-wave type shown in FIG. 6, for example, a voltage doubler formed by connecting two electrolytic capacitors in series. In the case of the shape configuration, it was almost the same.

In addition, since a permanent magnet is used for the rotor 21, it becomes expensive, and when the speed is as high as 40,000 revolutions or more, for example, as in the case of using a vacuum cleaner, The electric power supplied to the motor has a high frequency, and there is also a third problem that the loss (particularly, iron loss) of the motor increases.

In particular, in the structure of the inner rotor in which the rotor is located inside, the weight of the iron core used for the stator becomes considerably larger than the weight of the iron core used for the rotor, so that eddy current loss and hysteresis loss due to high frequency are affected. Therefore, it was difficult to reduce iron loss.

[0020]

In order to solve the above-mentioned first to third problems, the present invention provides a commercial power supply, a rectifier circuit which is output to the output of the commercial power supply and outputs a pulsating voltage, and An inverter device having an inverter circuit connected to the output of the rectifier circuit and an induction motor driven by the inverter circuit, wherein the output frequency of the inverter circuit is higher than the pulsating ripple frequency of the pulsating voltage. With this configuration, it is possible to realize a device having a high input power factor while reducing weight, volume, and cost, and to reduce loss (iron loss) of the motor.

[0021]

According to a first aspect of the present invention, there is provided a commercial power supply, and a rectifier circuit for outputting a pulsating voltage output to an output of the commercial power supply.
An inverter circuit connected to the output of the rectifier circuit, and an induction motor driven by the inverter circuit, wherein an output frequency of the inverter circuit is higher than a pulsating ripple frequency of the pulsating voltage; Thus, a small and inexpensive inverter device is realized.

According to a second aspect of the present invention, there is provided the inverter device according to the first aspect and a fan driven by a motor of the inverter device.
Motor can be driven at high speed, fan, motor, rectifier circuit,
Can have a simple and compact configuration.

According to a third aspect of the present invention, there is provided a storage battery,
An inverter circuit connected to the output of the storage battery, and an induction motor driven by the inverter circuit;
With the configuration having the fan driven by the electric motor, a low-cost and highly reliable vacuum cleaner is realized.

According to a fourth aspect of the present invention, there is provided a motor having a stator and a rotor rotatably provided outside the stator, an inverter circuit for driving the motor, and a fan driven by the motor. Having a configuration in which the stator has a stator winding to which current is supplied from the inverter circuit, thereby reducing the amount of copper wire required for the stator winding and reducing copper loss. Thus, the efficiency can be improved.

According to a fifth aspect of the present invention, the vacuum cleaner stator according to any one of the second to fourth aspects has a stator core, the rotor has a rotor core, The stator core has a configuration in which the mass is smaller than that of the rotor core, thereby achieving an improvement in efficiency by reducing iron loss of the stator core on which high-frequency magnetic flux acts.

[0026]

Next, specific examples of the present invention will be described.

(Embodiment 1) FIG. 1 shows the first embodiment of the present invention.
FIG. 9 is a circuit diagram of a vacuum cleaner having an inverter device according to the first embodiment using the second, fourth, and fifth aspects.

In FIG. 1, a commercial power supply 31 of 100 V and 60 Hz and a rectifier circuit 32 connected to the commercial power supply 31 are provided.

The rectifier circuit 32 is of a full-wave type, is composed of diodes 33, 34, 35 and 36, and outputs a pulsating voltage V1.

The output of the rectifier circuit 2 is connected to a plastic film type capacitor 37 having a capacitance of 4.7 microfarads.

The inverter circuit 38 operates by receiving the pulsating voltage V1 from the rectifier circuit 32 and includes switching elements 39, 40, 41, 42, 43, and 44.

The induction motor 45 is connected to the inverter circuit 3
8, which is based on a principle generally called an induction motor or an induction motor.

The electric motor 45 includes stator windings 46, 47, 4
8 and a rotor 49.

The control circuit 50 controls the switching elements 39, 40, 41, 42, 43, and 44 in turn at a cycle of 1 kHz so as to supply a driving current of 1 kHz from the inverter circuit 38 to the motor 45. It is.

With the above configuration, the inverter device 51
The impeller-type fan 52 is connected to the rotor 49 of the electric motor 45 to operate as a vacuum cleaner.

FIG. 2 is an operation waveform diagram of the smoothing circuit and the DC power supply according to the first embodiment.

FIG. 2A shows the input voltage V1 of the inverter circuit 38 of the vacuum cleaner according to the first embodiment, and FIG. 2A shows the waveform of the input current Iin from the commercial power supply 31.
(C) shows the waveform of one IM of the three-phase motor 45 input current.

The rectifier circuit 32 is a substantially full-wave rectified output voltage, and has a pulsating component (ripple component) that varies between 140 volts and 15 volts at maximum.

The frequency of the pulsation (pulsation ripple frequency) is
The frequency is twice the frequency of the commercial power supply 1, and when the commercial power supply 1 is 60 Hz, the frequency is 120 Hz.

In this embodiment, since the capacitance of the capacitor 37 provided at the output of the rectifier circuit 32 is small, the pulsating ripple component of the input voltage V1 of the inverter circuit 38 is
It has a considerable amplitude.

The electric current supplied to the electric motor 45 is shown in FIG.
As shown in (c), the waveform has a waveform of 1 kHz having an envelope of substantially the same shape as the input voltage V1 of the inverter circuit 38.

In this embodiment, since the motor 45 is formed by using an induction type motor, the induced electromotive force proportional to the speed is fixed as in the conventional motor using a permanent magnet. No current is generated in the secondary winding, and thus, in the same manner as when power is just supplied to the resistor, a current substantially proportional to the instantaneous value of the voltage V1 is supplied from the inverter circuit 38 to the motor 45, and the current is substantially squared. Proportional instantaneous power is supplied.

Therefore, the input current Iin of the apparatus from the commercial power supply 31 has a waveform substantially similar to a sine wave as shown in FIG. 2A, and has a high power factor and a low peak current value. Therefore, there is no adverse effect on other electric devices connected to the system, and the burden on the distribution system can be reduced, the utilization rate of the distribution device can be increased, and the loss can be almost minimized. It will be.

According to an experiment by the inventor, when the bottom value (voltage value at the lowest point due to pulsation) is 50% or less of the peak value of the voltage input to the inverter circuit 38, the above effect is obtained. It is known that it can be greatly obtained.

The plastic film type capacitor 37 used in the first embodiment has a small size, light weight, low cost, and long life as compared with the electrolytic type capacitor used in the prior art. In addition, since a large, heavy, and expensive choke coil is not used, there is a great effect on reducing the size, weight, cost, and reliability of the device.

However, when it is necessary to suppress line noise or the like, for example, a normal mode or common mode choke coil can be connected in series with the input part from the commercial power supply 31 or the output of the rectifier circuit 32.

Also in this case, the required inductance value can be smaller than that used in the prior art, so that the effect of the present invention can be sufficiently improved. Becomes

In this embodiment, at the time of startup, the frequency of the inverter circuit 38 is set to 100 Hz, and the frequency is gradually increased to 1 kHz, which is the frequency at the maximum rotation, over 0.8 seconds after startup. Therefore, the torque at the time of startup is large, the acceleration of the fan 52 is rapidly performed, and the current I supplied to the electric motor 45 is increased.
The effective value of M can also be kept low.

From the relationship between the speed and the torque of the fan 52, 2
Since the input power of the inverter device 51 at the time of starting at 00 Hz (speed of 5350 r / min) is only about 1/15 of that at 1 kHz, the voltage smoothing effect of the capacitor 37 acts considerably immediately after starting. Then, the waveform of the input voltage V1 of the inverter circuit 38 has a shape substantially similar to the inverter circuit input voltage waveform in the conventional technique shown in FIG.

Therefore, at the time of startup, the output frequency (100 Hz) of the inverter circuit 38 is changed to the rectifier circuit 32.
Although the condition is small relative to the pulsating ripple frequency (120 Hz) of the pulsating voltage from, the starting operation can be performed well.

FIG. 3 shows the motor 45 and the fan 5 according to the first embodiment.
FIG. 3A is a cross-sectional view of a section of the electric motor 45, and FIG. 3A is a vertical cross-sectional view.

FIG. 3A is a dashed line portion (motor 45 portion) of FIG.

In this embodiment, in particular, the stator 5
9 are provided.

The stator 59 includes a stator core 55 formed by laminating silicon steel sheets having a thickness of 0.2 mm, and a stator core 55
The stator windings 46, 47, 48 wound around the twelve slots (grooves) as shown in FIG.
7.

The rotor 46 is rotatably provided outside the stator 59. Aluminum is poured into the rotor core 56 and 20 slots (grooves) provided inside the rotor core 56. The formed secondary conductor 54 is also constituted by an aluminum casing 58.

Although not shown in FIG. 3A, the secondary conductor 54 has a twist generally called skew, and has a stable torque-speed characteristic with respect to spatial harmonics. ing.

The fan 52 is of an impeller type made of aluminum, and is mounted on the upper surface of a casing 58.

Also, ball-shaped bearings 60, 61
Are provided on the upper and lower sides, the lower part of the shaft 57 is hollow, and the stator windings 46, 47,
Holes are provided so that three wirings (lead wires) for connecting 48 to the inverter circuit 38 can pass therethrough.

This motor has a structure in which the lowermost portion of a shaft 57 is fixed, and is called an outer rotor that drives the fan 52 together with the outer casing 58.

By adopting the structure of the outer rotor,
The weight of the stator core through which the high-frequency magnetic flux generated by the high-frequency current flows from the inverter circuit 38 can be reduced.

In this embodiment, the mass of the stator core is 105
g, which is smaller than the rotor core 185 g.

In general, when the maximum magnetic flux density is constant, at a constant frequency, the iron loss per unit mass is determined by the material, and when the mass of the stator core is small, the iron loss is reduced accordingly. There is an effect that.

Further, since the amount of the stator core to be used is small, it is possible to design such that even if a high-quality one having excellent high-frequency characteristics is used, the cost increase is small.

On the other hand, since the rotor core 56 allows the passage of a magnetic flux of only the sliding frequency, which is far lower than the output frequency of the inverter circuit 38, it is not necessary to use a high-grade silicon steel sheet. Any material that can withstand the centrifugal force may be used.

Therefore, it is not always necessary to form the stator core 55 and the rotor core 56 together from the same silicon steel plate material.

Further, the length of the coil end portions of the stator windings 46, 47, 48, ie, the length of the copper wire going from slot to slot can be made shorter than that of the inner rotor type. This also has the effect of reducing the resistance of the copper wire and reducing the copper loss.

(Embodiment 2) FIG. 4 is a sectional view of an electric motor of an inverter device according to Embodiment 2 of the present invention.

In FIG. 4, the permanent magnets 62, 63, 6
4, 65, 66, and 67 have a rotor 69 that is adhered and provided inside a rotor core 68.

Regarding the permanent magnets 62, 63 and 64, the S pole is provided on the inner side, that is, on the side facing the stator.
The magnets 5, 66 and 67 are magnetized so that the inside has an N pole.

The configuration of this embodiment employs two poles in order to minimize the iron loss during high-speed rotation. In general, magnetization at a mechanical angle of 180 degrees has many problems in terms of performance and cost.
In the present embodiment, since three permanent magnets are used for one pole, the apparatus can be configured using a powerful and inexpensive permanent magnet such as a strontium ferrite magnet of parallel orientation. It will be.

The rotor core 68 uses a pipe-shaped steel material instead of a silicon steel plate.
All the centrifugal forces acting on the permanent magnets 62, 63, 64, 65, 66, 67 can be received, and measures to prevent the scattering of the permanent magnets, which is a problem in the case of the inner rotor configuration (for example, use of a SUS tube) ) Does not cause performance degradation.

Regarding the stator windings 46, 47 and 48,
Since it has a configuration having 24 slots, which is twice the number of slots in the case of the first embodiment, the distribution coefficient is slightly smaller than that of the first embodiment, and the permanent magnets 62, 63,
The waveform of the induced electromotive force generated in each stator winding when the 64, 65, 66, 67 rotates is closer to a sine wave, so that the generated torque ripple is small and noise and vibration are suppressed to a small value. This has the effect of being performed.

However, the number of slots of the stator is set to 24, which is not particularly limited to a motor using a permanent magnet, and may be 12 slots as shown in the first embodiment. Also, it can be configured with six slots.

In the second embodiment, the thickness of the stator can be made smaller than that in the first embodiment, and the mass of the stator core is 1 unit.
00g, but 9g for rotor core
0 g, and the permanent magnets 62, 63, 64, 65, 66,
Even if the mass of 67 is added, the weight can be significantly reduced with respect to the configuration of the first embodiment.

The other parts are exactly the same as the first embodiment.

The configuration of the second embodiment is generally a brushless DC
This is a motor or a motor of the type called a permanent magnet type synchronous motor.The outer rotor configuration reduces the weight of the stator core and reduces the core loss of the stator core where high frequency acts. Can be reduced.

Further, as shown in the first and second embodiments,
Even with distributed winding and concentrated winding, the coil width must be 1 electrical angle.
When the angle is set to 20 degrees or more, an overlapping portion occurs between the three-phase stator windings. In such a case, the length of the copper wire at the coil end portion can be suppressed, and the copper loss can be reduced. It can be done.

In particular, when a high speed such as 60,000 revolutions per minute is required, it is very important to suppress the iron loss of the stator. The use of two poles is effective in suppressing the frequency, but the salient pole concentrated winding, which is generally said to have the shortest coil end portion, cannot cancel the radial force with two poles. In addition, vibration and noise are problems, and they cannot be used in many cases.

Therefore, even in such a case, FIG.
By providing a stator winding having a required distribution coefficient in the configuration shown in (A), a high-efficiency motor can be obtained.

(Embodiment 3) FIG. 5 is a circuit diagram of a motor according to Embodiment 3 of the present invention.

In FIG. 5, a commercial power supply 71 of 100 V and 60 Hz, and a charging circuit 72 connected to the output of an AC power supply 71
Is provided.

Further, a connector 73 for freely connecting to and disconnecting from the charging circuit 72, a nickel-metal hydride storage battery 74,
A plastic film capacitor 75 connected to the output of the storage battery 74, an inverter circuit 38, an induction motor 45 driven by the inverter circuit 38, and an inverter device 76 constituted by a control circuit 50 for controlling the inverter circuit 38 are provided. I have.

In this embodiment, the six switching elements used in the inverter circuit 38 are MOS transistors.
It is configured using FETs.

The fan 52 is connected to the output of the motor 45 of the inverter device 76 and is driven.

The operation will be described above.

The user connects the connector 73 before use, and connects the storage battery 7 from the AC power supply 71 via the charging circuit 72.
4 and after the charging is completed, the connector 73 is disconnected and the inverter circuit 38 is operated by the energy stored in the storage battery 74 of the inverter device 76,
The electric motor 45 is supplied with high-frequency three-phase alternating current electric power of 1 kilohertz, and the fan 52 can be driven at a high speed of about 59,000 r / min to obtain powerful dust collection.

Here, the control circuit 50 controls each switching element in the inverter circuit 38 to turn on and off in order, so that a current having a waveform substantially close to a sine wave is supplied to each stator winding of the electric motor 45. The drive is performed efficiently.

When the dust collection operation is completed, the user puts the storage battery 74 into a state in which the storage battery 74 can be charged from the commercial power supply 71 through the charging circuit 72 by the connector 74, and charges the depleted storage battery 74 again, thereby performing the next cleaning. Be prepared for work.

As described above, since it is possible to use the apparatus in a state of being disconnected from the commercial power supply 71 during the cleaning operation, the operability is remarkably improved, and the fatigue of the body of the user is extremely reduced. .

Particularly, in this embodiment, since the induction type electric motor 45 is used, in addition to the effect that iron loss can be reduced as compared with the case where a permanent magnet is used, rotation is performed at a high speed such as 60,000 rotations. The driven fan 52 can be small and lightweight, and the structure of the motor can be made extremely robust against high-speed rotation by using, for example, a cage rotor, thereby improving portability. Become.

Further, compared to a configuration in which a motor using a commutator and a brush is used to directly supply the DC voltage generated from both ends of the storage battery 74 to the motor, the brush has high reliability because there is no brush wear. The effect is that the life is very long.

That is, when a direct current is supplied to a motor using a brush, since the polarity of the current is always constant, the problem that the brush is partially reduced is very likely to occur. According to the above, since the inverter circuit 38 supplies a current, such a problem can be completely prevented.

In this embodiment, the capacitor 7
5, which stabilizes the input voltage of the inverter circuit 38 and ensures the reliability of the storage battery 74 by bypassing the high frequency component of the current flowing through the inverter circuit 38. If the impedance to high frequencies is low enough,
Alternatively, a very small capacitance can be used.

[0094]

As described above, the invention according to claim 1 of the present invention is particularly applicable to a commercial power supply, a rectifier circuit which is output to the output of the commercial power supply and outputs a pulsating voltage, And an inductive motor driven by the inverter circuit, the output frequency of the inverter circuit being larger than the pulsating ripple frequency of the pulsating voltage. And an inexpensive inverter device.

According to a second aspect of the present invention, in particular, by including the inverter device according to the first aspect and a fan driven by a motor of the inverter device, the motor can be driven at a high speed, The motor and the rectifier circuit can have a simple and compact configuration.

According to a third aspect of the present invention, there is provided, particularly, a storage battery, and an inverter circuit connected to an output of the storage battery.
By having an induction type electric motor driven by the inverter circuit and a fan driven by the electric motor, a low-cost and highly reliable vacuum cleaner is realized.

According to a fourth aspect of the present invention, there is provided a motor having a stator and a rotor rotatably provided outside the stator, an inverter circuit for driving the motor, and a motor driven by the motor. By having a fan, the stator has a configuration having a stator winding to which current is supplied from the inverter circuit, thereby reducing the amount of copper wire required for the stator winding and reducing copper loss. It is intended to achieve an improvement in efficiency by reduction.

According to a fifth aspect of the present invention, in particular, the vacuum cleaner stator according to any one of the second to fourth aspects has a stator core, and the rotor has a rotor core. The stator core has a configuration in which the mass is smaller than that of the rotor core, thereby realizing an improvement in efficiency by reducing iron loss of the stator core on which high-frequency magnetic flux acts.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a vacuum cleaner having an inverter device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the smoothing circuit and the DC power supply device.

FIG. 3 is a configuration diagram of an electric motor and a fan.

FIG. 4 is a circuit diagram of a vacuum cleaner according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a vacuum cleaner according to a third embodiment of the present invention.

FIG. 6 is a circuit diagram of a vacuum cleaner having an inverter device according to the related art.

FIG. 7 is an operation waveform diagram of the inverter device.

[Description of Signs] 31 Commercial power supply 32 Rectifier circuit 38 Inverter circuit 45 Electric motor 51 Inverter device 52 Fan 74 Storage battery 59 Stator 49, 69 Rotor 46, 47, 48 Stator winding 55 Stator core 56, 68 Rotor core

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasudo Kobayashi 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 3B006 FA01 3B057 DA01 DE01

Claims (5)

[Claims] 1. A commercial power supply, a rectifier circuit output to the output of the commercial power supply to output a pulsating voltage, an inverter circuit connected to an output of the rectifier circuit, and an inductive type driven by the inverter circuit. An inverter device comprising a motor, wherein an output frequency of the inverter circuit is higher than a pulsating ripple frequency of the pulsating voltage. 2. A vacuum cleaner comprising: the inverter device according to claim 1; and a fan driven by an electric motor of the inverter device. 3. A vacuum cleaner comprising a storage battery, an inverter circuit connected to an output of the storage battery, an induction motor driven by the inverter circuit, and a fan driven by the motor. 4. An electric motor having a stator and a rotor rotatably provided outside the stator, an inverter circuit for driving the electric motor, and a fan driven by the electric motor, wherein the stator is A vacuum cleaner having a stator winding to which current is supplied from the inverter circuit. 5. The stator according to claim 2, wherein the stator has a stator core, the rotor has a rotor core, and the stator core has a smaller mass than the rotor core. The vacuum cleaner according to claim 1.