JP2003244855A - Cordless apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exclude a contact by reducing the weight of a charger in a cordless apparatus. <P>SOLUTION: This cordless apparatus is equipped with a body 101, which has a step-down chopper circuit 106 having a choke coil 120 and an accumulating element 105, and a charger 102, which has a DC power source 133, an exciting coil 142, and a second switching element 140, and this exciting coil 142 is coupled magnetically with the choke coil 120 at charging. Hereby, a cordless apparatus, which enables charging without a contact and further is light-weight, can be provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a power tool,
Related to cordless devices used in electric razors, notebook computers, mobile phones, vacuum cleaners, etc., that are capable of supplying electrical energy to a load after the electrical energy is precharged and the charger and main body are disconnected Is.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, a cordless device of this type has a charger 2 connected to an AC power source 1 of 100V60Hz and a main body 3 which is detachably attached to the charger 2. A transformer 4 for converting an input voltage from the power source 1 into a low voltage of, for example, 24V, a full-wave rectifier 5 connected to the secondary side of the transformer 4 for converting AC to DC, and connected to the output of the rectifier 5. It had contacts 6 and 7 that make electrical contact when it was attached to and detached from 3.

Further, the main body 3 has a storage element 8 using a nickel cadmium battery or the like, a switch 9 and a load 10 using a motor. When the switch 9 is turned on, the main body 3 is a charger. In the state of being separated from 2, that is, the state where the contacts 6 and 7 are both separated, the storage element 8
The electric power can be supplied to the load 10 through the switch 9 from the above, and it can be used even in a cordless state.

[0004]

However, in the cordless device having the above-mentioned conventional structure, the transformer 4 which is a constituent element of the charger 2 operates at a low frequency of 50 Hz or 60 Hz, so that the shape and weight are large. If you need to carry the charger 2 in the bag at the same time as the main body 3 during a business trip,
The first problem is that the burden on the user is heavy.

The transformer 4 may be provided inside the main body 3, but in this case, the shape and weight of the main body 3 become large, and the usability is very poor when used in a cordless state. Therefore, the burden on the user is further increased.

Further, there is a second problem in that when the contact is soiled due to the presence of the contact, contact failure may occur and charging may not be possible.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a cordless device which is compact and lightweight and can be charged without a contact.

[0008]

In order to solve the above-mentioned conventional problems, a cordless device of the present invention comprises a main body having a step-down chopper circuit having a choke coil and a first switching element, a storage element and a load. A DC power supply, an exciting coil, and a charger having a second switching element,
The excitation coil is magnetically coupled to the choke coil during charging, which reduces the shape and weight of the charger and improves usability. By using magnetic coupling, the cordless device can perform charging operation without contacts. Is provided.

[0009]

A first aspect of the present invention is a main body having a step-down chopper circuit having a choke coil and a first switching element, a storage element and a load, a DC power source, an exciting coil and a second switching element. A charger having an element, and the excitation coil is magnetically coupled to the choke coil at the time of charging, so that the charger is small and lightweight and easy to use, and the power transfer by magnetic coupling is used to charge without a contact. A cordless device that can operate is provided.

According to a second aspect of the present invention, there is provided a main body having a choke coil, a sign inverting chopper circuit having a first switching element, a storage element and a load, a DC power source, an exciting coil and a second switching element. A charger is provided, and the exciting coil is magnetically coupled to the choke coil at the time of charging, so that the charger is also small and lightweight and easy to use, and the power transfer by magnetic coupling allows the charging operation without contacts. It provides a cordless device that can be used.

The invention as defined in claim 3 is particularly defined by claim 1.
Alternatively, the main body is provided with a charging diode that is connected to the choke coil described in 2, and that supplies a charging current to the storage element during charging, thereby allowing the choke coil to function effectively even during charging and effectively store electricity. It is intended to realize a cordless device which can supply the charging current of the element and has a small loss.

The invention as defined in claim 4 is particularly characterized by claim 3.
By connecting the charging diode of the cordless device described above in parallel with the first switching element, it is possible to prevent the reverse voltage from being applied to the first switching element to ensure reliability and also to charge the choke coil. It is intended to realize a cordless device that functions effectively and can effectively supply the charging current of the power storage element with less loss.

The invention as defined in claim 5 is particularly characterized by claim 1.
Alternatively, the load described in 2 is configured such that the electric power from the DC power supply is supplied by the on / off operation of the second switching element in a state where the choke coil and the exciting coil are magnetically coupled to each other. Even if the battery is not fully charged, the load power can be supplied from the DC power source to the DC power source, and a cordless device with good usability is realized.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a circuit diagram of a cordless device according to a first embodiment of the present invention. In FIG. 1, a main body 101 and a charger 10 detachable from the main body 101
2, and the charger 102 is connected to the AC power supply 103 of 100V 50Hz or 60Hz. The main body 101 is composed of a commutator motor 2
A load 104, which operates well with a DC voltage of 4 V, and 10 AA nickel-metal hydride batteries connected in series with a rated voltage of 12
It is composed of a storage element 105 having a voltage of V, a step-down chopper circuit 106, capacitors 107 and 108, a charging diode 109, and switches 110 and 111. The boost chopper circuit 106 includes a choke coil 120 in which an enameled wire is wound around a ferrite core, a first switching element 121 using a transistor, a diode 122, and a drive circuit 1 for controlling on / off of the switching element 121.
23, and the charging diode 124 is connected in parallel with the first switching element 121.

One of the chargers 102 has a diode 4
Full wave rectifier 130 and choke coil 13 using a book
1, a capacitor 132, and a DC power supply 133 that outputs a DC voltage of about 130 V.
The output of 3 is composed of a second switching element 140 using an IGBT and a drive circuit 141 for controlling ON / OFF of the switching element 140, an E-shaped wire wound around a U-shaped ferrite core, and a choke coil 120 for charging.
Exciting coil 142 that is magnetically coupled with, and further capacitor 1
The one in which 43 and the resistor 144 are connected in series is connected in parallel to the exciting coil 142.

Since the exciting coil 142 using a U-shaped ferrite core and the choke coil 120 using a rod-shaped ferrite core are used, the cordless device of this embodiment is magnetically coupled during charging. Although it is comparatively good and can operate with high efficiency, these constituent elements may be those capable of magnetic coupling, and may have a shape other than that of the present embodiment.

The charging diodes 109 and 124 are the main body 1
01 provided in the second switching element 1 at the time of charging.
It becomes conductive during the OFF period of 40 and supplies the charging current to the storage element 105.

FIG. 2 shows an operation waveform diagram during charging of the cordless device of the present embodiment. (A) shows a gate voltage waveform Vge of the second switching element 140, (A).
Is the current I1 of the second switching element 140, (c) is the current I2 of the choke coil 120, and (d) is the collector-emitter voltage Vce of the second switching element 140.
2 shows the waveform.

At this time, the switch 110 is on, the switch 111 is off, and the first switching element 121 is kept off.

The driving circuit 141 turns on and off the second switching element 140 at a frequency of 50 kHz during the charging operation during charging and sets the on time to 8 μs, so that the charging current of the storage element 105 is approximately 1 A. I am trying. The period from t1 to t2 is an ON period, during which Vce becomes substantially zero, and the output voltage of the DC power supply 133 is almost applied to the exciting coil 142. Here, since the black circle has a positive voltage, the voltage generated in the magnetically coupled choke coil 120 also has a positive polarity, so that the charging diode 109 has a positive polarity.
Is reversely blocked, and the choke coil 120 current does not flow. Therefore, due to the inductance of the exciting coil 142, the current increases with time and becomes 800 mA at t2.

At t2, the second switching element 1
When 40 enters the off period, the magnetic energy stored during the on period causes a voltage to be generated in the direction in which the black circle mark becomes negative, and the charging diode 109 and the charging diode 124 are discharged from the choke coil 120. Through this, the charging current flows through the storage element 105. Since the charging diode 124 is connected in parallel between the collector and the emitter of the first switching element 121, for example, when the silicon semiconductor charging diode 124 is used, the collector and the emitter of the first switching element 121. The voltage applied during this period is approximately -1 V, which makes it possible to suppress the performance deterioration due to the application of a reverse voltage, and it becomes possible to perform highly reliable and highly efficient charging operation.

In this embodiment, the first switching element 12 is a bipolar NPN transistor.
However, other types of switching elements such as MOSFETs may be used.

After that, at t3, the ON period starts again, and by repeating this operation, the storage element 1
The charging current is continuously supplied to 05 to be charged.

Since such an operation is performed at a switching frequency of 50 kHz and has a value much higher than the commercial frequency, the choke coil 120 is much smaller and lighter than the conventional transformer. Excitation coil 1
Since it can be configured with 42, the shape and weight of the charger 102 can be reduced.

The second switching element 140 is T
It can be configured with a small and lightweight package such as an O-220 package, and the charging diodes 109 and 124 can also be a small fast recovery type package.

FIG. 3 shows operation waveforms when used in a cordless state. (A) is a gate current Ib of the first switching element 121, (a) is a collector current I3 of the first switching element 121. , (C) is the current I2 of the choke coil 120, and (d) is the collector-emitter voltage Vce of the first switching element 121.
The waveform of 1 is shown. During use, the charger 102 is removed, and the switches 110 and 111 are turned on by the operation of the user. Drive circuit 12
In No. 3, at the time of use, the output voltage V3 to the load 104 is set to 6.3V by also turning on and off the first switching element 121 at a frequency of 50 kHz and setting the on time to 11 μs.

It is also possible to change the ratio of the on-time of the first switching element 121 to adjust the DC voltage supplied to the load 104, thereby varying the power of the load 104, which is a commutator motor, for example. It is also possible to adjust the rotation speed and torque. The period from t1 to t2 is an ON period, and during this period, current flows from the positive terminal of the storage element 105 to the first switching element 121, the choke coil 120, the load 104, the switch 110, the switch 111, and the negative terminal of the storage element 105. Supplied. The period from t2 to t3 is an off period, and during this period, the choke coil 1 is turned on during the on period.
Current is supplied from the choke coil 120 to the load 104 by the magnetic energy stored in the switch 20, and the switch 1
11, the current is supplied through the path passing through the diode 122 and the diode 122. Therefore, the step-down chopper circuit 106, which is a one-stone type, operates in a step-down manner during use.

Since the switching frequency of the first switching element 121 is set to a considerably high value of 50 kHz, the choke coil 120 is small and lightweight.
However, when it is used, it can be used by sufficiently satisfying the function of the step-down chopper circuit 106, and it is possible to supply power to the load 104 with low loss and reduce energy loss. Becomes

Further, switching operation at high frequency is also possible, and the choke coil 120 having a small inductance.
Since it can be used, there is also an effect that the main body can be downsized.

The value of the inductance of the choke coil 120 when using the cordless is determined by the exciting coil 142.
In the absence of the magnetic field, the magnetic resistance of the magnetic circuit tends to increase and the magnetic resistance tends to decrease. However, even under such a condition, the configuration of the present embodiment that performs switching operation at high frequency is effective. Will act on.

FIG. 4 is a circuit diagram of the present embodiment when used with a cord. In the cordless device of this embodiment, when the storage element 105 is not sufficiently charged, the main body 101 is set in the charger 102, that is, the choke coil and the exciting coil are magnetically coupled, and the switch 110 is turned off. , The switch 111 is turned on, and the second switching element 140 is turned on / off to supply electric power from the DC power supply 133 to the load 104, so that the load 104 can be used.

In FIG. 4, the black circles indicating the polarity of the exciting coil 142 are opposite to those in FIG. When used in a state with a cord, when the main body 101 is set in the charger 102, unlike the case where charging is performed, the main body 101 is attached in the opposite direction, so that the U-shaped exciting coil 142 is attached.
The core has a polarity opposite to that of the choke coil 120 and is magnetically coupled.

5A and 5B are views showing a state of magnetic coupling between the exciting coil 142 and the choke coil 120. FIG. 5A shows a state of charging and FIG. 5B shows a state of using a cord. That is, the end a of the exciting coil 142 and the end c of the choke coil 120 face each other at the time of charging, and the end b of the exciting coil 142 faces the end d of the choke coil 120. Since the direction of the charger 102 with respect to 101 is left-right reversed, the excitation coil 1
The b end of 42 and the c end of the choke coil 120 are opposed to each other, and the a end of the exciting coil 142 and the d end of the choke coil 120 are opposed to each other. Therefore, the charger operates in the same manner as the charging operation described above, so that instead of supplying the charging current to the storage element 105 in the charging operation, the load 1
Current is supplied to 04, and operation is performed with a cord.

Therefore, for example, when the storage element 105 is not sufficiently charged, or when the stored energy is exhausted while the storage battery 105 is being used, it can be used in the state of being set in the charger 102, and the AC power supply 1
Although connection to 03 is required, it can be used without waiting for the storage element to be charged, which has the effect of improving usability.

As described above, in the present embodiment, the choke coil 120 is reasonably used both when charging and when used cordlessly, and when used with a cord.
Since it operates, the efficiency is high and wasteful heat generation can be suppressed.

The voltage of the DC power supply 133 during charging is 1
It is 30V, and can be realized with a simple configuration in which the 100V AC power supply 103 is directly rectified and used.

In the present embodiment, during charging, the charging diode is in a conducting state during the off period of the second switching element 140, and operates as a flyback converter in a general switching power supply. Therefore, the number of winding components can be minimized, and the charging operation can be performed with a simpler configuration than that of a circuit configuration such as a forward converter.

The second switching element 1 during charging
During the on-time of 40, the charging diodes 109 and 124 are in the reverse blocking state, which suppresses the outflow of current from the storage element 105, so that the charging operation is efficiently performed.

In addition, from the main body 101 during charging to the charger 10
Since the energy transfer to 2 is performed by magnetic coupling without using contacts, extremely excellent cordless equipment can be realized without contact failure due to dirt on contacts or reliability problems. .

(Embodiment 2) FIG. 6 shows a circuit diagram of a cordless device according to a second embodiment of the present invention, which is ready for charging. Also in FIG. 6, the configuration of the charger 102 is the same as that of the first embodiment.

Regarding the structure of the main body 101, the storage element 1
05, the load 104, the capacitors 107 and 108, and the switches 110 and 111 are also configured by using the same components as those in the first embodiment, but in the present embodiment, they are used in the first embodiment. Step-down chopper circuit 106
The code inversion chopper circuit 150 is used instead of the above configuration, and the configuration of the code inversion chopper 150 is the same as that of the first embodiment.
20, first switching element 121, drive circuit 123
However, there is a difference in the way of connecting them.

That is, in the present embodiment, one terminal of the choke coil 120 is connected to the emitter terminal of the first switching element 121 as in the first embodiment, but the other terminal of the choke coil 120 is connected. Differs from the first embodiment in that it is connected between the series circuits of the switches 110 and 111, and is provided with a diode 151. From the cathode terminal of the diode 151, the choke coil 120 and the first switching element 121 are connected. It has been connected to the emitter terminal of. Note that the anode terminal of the diode 150 is connected to one end of the load 104, and operates as a sign inversion chopper in which the polarity of the potential of the upper terminal of the load 104 is negative.

The operation of the above configuration will be briefly described.

First, at the time of charging, with the main body 101 set in the charger 102, the choke coil 120 is placed magnetically coupled to the exciting coil 124 as shown in FIG. The second switching element 140 is ON / OFF controlled by the drive circuit 141, so that the same operation as shown in FIG. 2 is performed, and the second switching element 140 is connected in parallel between the collector and the emitter of the first switching element 121. Current is supplied to the power storage element 105 through the charging diode 124 to perform charging.

In this state, the switch 11
The operation is performed when 0 is on and the switch 111 is off.

FIG. 7 shows an operation waveform diagram of each part of the cordless equipment of this embodiment when it is used in a cordless manner. (A) shows the first switching element 121.
The base current Ib of the first switching element 1
21 collector current I3, (c) is choke coil 12
A current I2 of 0, (d) shows a current I4 flowing in the diode 151, and (e) shows a waveform of the collector-emitter voltage Vce1 of the first switching element 121. It should be noted that when used in a cordless manner, the switches 110 and 111 are both in the ON state, and the choke coil 120 is in a state where there is no magnetic coupling with the exciting coil 124.

11 microseconds, which is a period from t1 to t2, is an ON period, and the storage element 105 is in this period.
Then, the DC output voltage of the storage element 105 is applied to the choke coil 120 through the first switching element 124, and the current waveform linearly increases. During this period, the diode 151 is in the reverse blocking state. .

Next, when the first switching element 121 is changed from the on state to the off state at t2 by the action of the driving circuit 123, the choke coil 12 is turned on during the on period.
Due to the magnetic energy stored in 0, the current I4 is supplied to the load 104 through the diode 151. At this time, the voltage on the upper side of the load 104 becomes negative, the sign of the voltage of the storage element 105 is inverted, and the operation is performed as a circuit generally called a sign inversion chopper circuit.
The magnitude of the voltage is large when the ON time ratio of the first switching element 121 is large. Therefore, by adjusting the ON time ratio (ON duty), the power to the load 104 is adjusted. When the ratio of the ON time of the first switching element 121 is larger than 50% as in this embodiment, the voltage is 16V higher than the voltage of 12V which is the voltage of the storage element 105.
Are supplied to the load 104.

Therefore, the load 104 which is a commutator motor
In addition, the higher the applied voltage is, the smaller the value of the current in the constant electric power supply can be reduced, and the effect that the highly reliable operation can be achieved.

Further, similarly to the first embodiment, in the cordless device of the present embodiment, the charger 102 and the main body 101 are combined so that the electric power from the DC power supply 133 is used by the load 104. Can be used in a state with a cord regardless of the energy stored in the storage element 105. In that case, the exciting coil 14
For the method of connecting the 2 and the choke coil 120,
As shown in FIG. 5, it is assumed that the device is placed in a direction different from that during charging, and the operation is the same as that in the first embodiment. In this case, the switch 110 is off and the switch 11
1 is turned on.

Therefore, also in the second embodiment, the choke coil 120, which is a constituent element of the sign inversion chopper circuit 150, has a highly efficient voltage conversion function when using a cordless type, and is also coupled with the exciting coil 142 during charging. Therefore, it can be effectively used for charging power supply without contacts, and even in the operation with a cord, the electric power from the DC power supply 133 is still received and the load 10
4 can be used and is very effectively utilized.

[0053]

As described above, according to the present invention, it is possible to provide a cordless device which is compact and lightweight and which can perform charging operation without contacts.

[Brief description of drawings]

FIG. 1 is a circuit diagram during charging of a cordless device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the cordless device during charging.

FIG. 3 is an operation waveform diagram of the cordless device when using cordless.

FIG. 4 is a circuit diagram of the cordless device when used with a cord.

FIG. 5 (a) is a state diagram showing the state of magnetic coupling between the excitation coil and the choke coil when charging the cordless device, and FIG. 5 (b) is the state diagram showing magnetic coupling between the excitation coil and the choke coil when using the cordless device with a cord. State diagram showing the state of

FIG. 6 is a circuit diagram during charging of the cordless device according to the second embodiment of the present invention.

[Fig. 7] Fig. 7 is an operation waveform diagram of the cordless device when the cordless device is used.

FIG. 8 is a circuit diagram of a conventional cordless device.

[Explanation of symbols]

120 choke coil 121 First switching element 106 Step-down chopper circuit 105 storage element 104 load 101 main body 133 DC power supply 142 Excitation coil 140 Second switching element 102 charger 150 Sign inversion chopper circuit 109, 124 Charging diode

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5G003 AA01 BA01 GB04 GB08                 5H030 AA08 AA09 AS11 BB01 BB21                       DD18                 5H730 AA11 AA15 AS17 BB03 BB08                       BB23 BB43 BB57 CC01 CC25                       DD03 DD04 DD32 EE07 EE38                       EE39 EE60 FG02

Claims (5)

[Claims] 1. A main body having a choke coil, a step-down chopper circuit having a first switching element, a storage element, and a load, a DC power supply, an exciting coil, and a charger having a second switching element. The coil is a cordless device that is magnetically coupled to the choke coil during charging. 2. A main body having a code inversion chopper circuit having a choke coil, a first switching element, a storage element and a load, a DC power supply, an exciting coil, and a charger having a second switching element. The excitation coil is a cordless device that is magnetically coupled to the choke coil during charging. 3. The cordless device according to claim 1, further comprising a charging diode, which is connected to the choke coil and supplies a charging current to the storage element during charging, in the main body. 4. The cordless device according to claim 3, wherein the charging diode is connected in parallel with the first switching element. 5. The cordless device according to claim 1, wherein the load is a state in which the choke coil and the exciting coil are magnetically coupled to each other, and the second switching element is turned on / off to supply electric power from the DC power supply. .