JPH04137386A - Induction heating cooker - Google Patents

Abstract

PURPOSE:To reduce a transmission noise leaking to a power source cable through the distribution capacity between an earth cable and power source cables by combining electromagnetically both cables so as to generate an electromotive force to set off the other current each other by the same phase of current flowing in each cable of the earth cable and the power source cables. CONSTITUTION:By combining electromagnetically an earth cable 18c to power source cables 18a and 18b through a ferrite core 18d, and setting off the same phase of input signals each other, the symmetric component of a transmission noise transmitting from a frequency converter 13 to a metal case 20, and leaking to the power source cable 17a or the power source cable 17b by the distribution capacity between the power source cables 17a and 17b, and the earth cable 17c can be removed effectively. Furthermore, the asymmetric component of the high-frequency transmission noise induced between nondischarging metallic parts such as the metal case 20 to house the frequency converter and an inner chassis, and the earth, can be filtered from the earth cable effectively.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an induction heating cooker.

Conventional technology In recent years, induction heating cookers have increased in output and power supply voltage has increased to 200V.
is being promoted. On the other hand, induction heating cookers have a built-in frequency converter that generates high-frequency large currents, and as they support higher output and 200V, the noise components generated from the frequency converter also increase. Reducing terminal noise leaking to the ground has become an important issue.

Conventionally, a common mode choke coil 3 is installed between the frequency converter 1 and the commercial power source 2 as shown in FIG. is installed.

Problems to be Solved by the Invention However, in this configuration, the ground wire 4 is usually housed in a resin or metal tube 6 with a length of 1 to 2 meters in close proximity to the power supply wire 5, as shown in FIG. Distributed capacitance (capacitance) that exists between the power supply line 5 and the ground line 4 because it is connected to the commercial power supply 2 or the ground 8
11, there is a risk that noise components of 10 megahertz or higher induced into the metal case 29 by the high frequency electromagnetic field radiated from the frequency converter may bypass the power line 5 via the ground wire 4 and leak.

Furthermore, in order to reduce conduction noise that affects equipment connected to a grounded power supply via the metal case 9 and the ground wire 4, a configuration as shown in Japanese Patent Publication No. 16621/1983 has been proposed. . As shown in FIG. 6, a ground coil 10 is provided on a ground wire 4 between a metal case 9 housing a frequency converter 1 and a ground 8.

In the above configuration, the electromagnetic waves generated by the steep current and voltage waveforms generated by the frequency converter 1 leak as conduction noise to the grounded commercial power source via the metal case 9 and the earth 8, and cause other electronics connected to this power source to leak. The earth coil 10 reduces the influence on the equipment.

However, in the configuration shown in this Japanese Patent Publication No. 61-16621, experiments show that 700 microhenries to 1
An inductance on the order of milli-Henry has little effect in reducing conduction noise of 20 to 30 MHz leaking to the power line via the distributed capacitance between the 10 to 20 Hz power line 5 and the ground line 4. In order to have a reduction effect, it is necessary to increase the number of turns of the wire or to make the core shape considerably larger in order to increase the inductance. On the other hand, the ground wire 4 that connects the earth and the metal case 9 needs to have a certain thickness or more so that a predetermined current can flow for safety in the event of an electric leak, and the ground coil 10 also needs to have a thick line. Even if the number of turns of the earth coil 10 is increased or the shape of the core is made larger, the overall shape of the earth coil 10 becomes larger and heavier, making it difficult to store and increasing the cost. There was a problem that there were limitations, and there were also limits to the effectiveness of reducing conducted noise.

The present invention solves these problems by eliminating conducted noise of 10 MHz or more that leaks from the grounded metal case or chassis to the ground wire and then to the power line via the distributed capacitance between the ground line and the power line. The first priority is to reduce
As the purpose of

Second. The third purpose is that the induction cooker can be installed on a worktop that is electrically conductive and grounded, like a stainless steel sink, rather than being used with a resin or wooden top. If the frequency converter is contaminated, high-frequency conduction noise leaks from the frequency converter to the grounded conductive external casing that houses it, leaks to the ground from the worktop that abuts the external casing, and causes high-frequency conduction noise that leaks from the external casing or internal non-conductor. This reduces high-frequency conduction noise of 10 MHz or higher that leaks from the ground wire connected to the live metal part to the power line via the distributed capacitance between the ground line and the power line.

The fourth purpose is the second. In addition to the third purpose, when the device is incorporated into a thin metal worktop, it reduces the deflection of the worktop due to the weight of the device.

Means for Solving the Problems In order to achieve the above first object, an induction heating coil,
A frequency converter that converts a commercial power source into a high-frequency current and supplies the high-frequency current to the induction heating coil, and an external casing made of a conductor or a non-conductor that houses or fixes the frequency converter that is grounded to the earth by a ground wire. The power supply line and the ground line, which are arranged between the commercial power source and the frequency converter, are magnetically arranged so that in-phase currents flowing through the respective lines generate an electromotive force that cancels each other's currents. It is a combination.

Further, in order to achieve the second object, the present invention includes an induction heating coil, a first external casing made of a conductive material, housing the induction heating coil, and abutting the worktop, a frequency converter that converts the high-frequency current and supplies the high-frequency current to the induction heating coil; and a second external casing or internal non-charged metal parts made of a conductive material that is grounded by a ground wire and houses or fixes the frequency converter. and a magnetic coupling body that generates an electromotive force such that in-phase currents flowing through the power supply line and the ground line, which are disposed between the commercial power source and the frequency converter, cancel each other's currents; The first external casing and an inductance element disposed on a conductive wire electrically connecting the second external casing or the internal non-charged metal parts are provided.

Furthermore, in order to achieve the third object, the present invention includes an induction heating coil, a frequency converter that converts a commercial power source into a high frequency current and supplies the high frequency current to the induction heating coil, and an insulating pot to be heated. At the same time, there is a mounting plate that contacts the worktop at its periphery, and a mounting plate that houses the frequency converter or the heating coil and is made of a conductive material and is grounded to the earth by a ground wire, and is mounted on the back side of the mounting plate. Keeping a predetermined distance inward from the periphery, an in-phase signal flows through the external casing whose upper side wall is fixed, and the power supply line and the ground line, which are disposed between the commercial power source and the frequency converter. The magnetic coupling body generates an electromotive force such that the currents of the two cancel each other out.

Furthermore, in order to achieve the fourth object, the present invention includes an induction heating coil, a first external casing made of an insulating material, housing the induction heating coil, and abutting the worktop, a frequency converter that converts the high-frequency current and supplies the high-frequency current to the induction heating coil; and a second external casing or internal non-charged metal parts made of a conductive material that is grounded by a ground wire and houses or fixes the frequency converter. and a magnetic coupling member that generates an electromotive force that causes in-phase currents flowing through the power line and the ground line, which are disposed between the commercial power source and the frequency converter, to cancel each other's currents. It is.

Operation The induction heating cooker of the present invention has the configuration of the first means, and magnetically couples the ground wire and the power wire so that currents of the same phase flowing through the respective wires generate an electromotive force that cancels each other's currents. As a result, the asymmetrical components of the high-frequency noise of the electromagnetic waves generated from the frequency converter cancel each other out, effectively blocking the leakage of high-frequency noise from the ground wire at the exit of the equipment. It is possible to effectively reduce leakage to the power line through the distributed capacitance between the ground wire and the power line of the power cable in which the line and the power line are bundled. Therefore, it is possible to effectively eliminate conduction noise of 10 to 30 MHz, which is difficult to eliminate by simply arranging a ground inductor on the ground wire. This magnetic coupler can be realized, for example, by winding the ground wire and the power wire several turns each around a single magnetic ferrite ring, and reduces the high frequency noise of 10 to 30 MHz leaking from the ground wire to the power wire by 10 dB.
Therefore, the shape of this magnetic coupling body can be made relatively small even if the power supply line and ground line that constitute it are made thicker. Even if the power supply and the external casing come into contact due to an accident and a large current flows through the ground wire, there is no risk of the ground wire generating heat or disconnection, and the power wire windings can be made of small components that generate less heat. can.

Further, according to the configuration of the second means, a magnetic coupling body is provided that generates an electromotive force that causes in-phase currents flowing in each of the ground wire and the power supply wire to cancel each other's currents, so that the frequency converter as described above can be used. Conducted noise leaking from the ground wire to the power line via the distributed capacitance between the ground line of the power cable and the power line can be reduced. Furthermore, there is a first external casing that houses the induction heating coil and is made of a conductive material, and a second external casing that houses the frequency converter or the frequency converter that is grounded to the earth by a ground wire and is also grounded. The first external casing is connected to the second external casing or the internal non-charging metal parts by connecting them with a conductive wire and providing an inductance element to this conductive wire. The first external casing is grounded through the component to ensure safety, and the first external casing and the second external casing or internal non-charged metal parts are separated at high frequency.

Generally, current with a steep waveform does not flow through an induction heating coil, so radiation of high frequency noise components of 10 MHz or higher from the heating coil is relatively small.However, a frequency converter that supplies the current of this induction heating coil includes switching elements, capacitors, etc., and a steep current with an extremely large peak current value is applied to it, which causes a lot of radiation of high-frequency noise as described above. The present invention has a first external casing that houses the heating coil, and when it is incorporated into a worktop, the circumference of this external casing comes into contact with the worktop.
As mentioned above, since the heating coil emits a small amount of high-frequency noise, the high-frequency noise induced from the heating coil to the first external casing is small. There is little high-frequency noise leaking to earth via stainless steel worktops, etc. In addition, the first external casing is separated from the second external casing that houses the frequency converter, which leaks a lot of high-frequency noise, or from the internal non-charged metal parts, so the high-frequency noise generated by the frequency converter It is also possible to reduce the level of high-frequency noise that leaks into the ground through the worktop.

Further, according to the configuration of the third means, a magnetic coupling body is provided that generates an electromotive force that causes the in-phase currents flowing in the ground wire and the power wire to cancel each other's currents, so that the frequency converter as described above can be used. It is possible to reduce conduction noise that leaks from the ground wire to the power wire via the ground wire. In addition, since the upper part of the side wall of the external casing housing the heating coil or frequency converter is fixed to the above-mentioned mounting plate while maintaining a predetermined distance inward from the periphery of the insulating mounting plate, the outer casing Even if the body is made of a conductive material, there is no risk that high frequency noise from the frequency converter leaking into the external casing will leak to the ground via the worktop.

According to the configuration of the fourth means described above, since the in-phase currents flowing in the ground wire and the power supply wire create a magnetic coupling that generates an electromotive force that cancels out each other's currents, the frequency converter can be used as described above. It is possible to effectively reduce conduction noise leaking to the power supply line via the first external casing or internal chassis to be housed and the ground line. The first housing the heating coil.
Since an external casing is provided, when it is assembled into a worktop, the circumference of this external casing will come into contact with the worktop, but the first external casing is made of an insulating material. Therefore, the high frequency noise of the frequency converter will not leak to the ground via the worktop, and the heating coil will not have a steep waveform of current flowing through it, so even if you use insulating material such as resin in this part. There is little risk that radiation noise will increase. Furthermore, if resin, which is a lightweight insulating material, is used for the first external casing, the first external casing will be lightweight, so the strength of the holding structure that holds it when it is assembled into a worktop can be reduced. The holding structure can be simplified, and the amount of deflection due to the load of the equipment can be reduced when it is incorporated into a thin worktop.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, a low frequency power source is passed from a commercial power source 14 to an outlet 15, a plug 16, a power cord 17, and a filter coil 18 to a frequency converter 13 that supplies a high frequency current to a heating coil 12 that heats a load. is supplied.

The outlet 15 is made up of three terminals, and the terminal 15c is connected to the ground 19, and the power plug 16 is made up of terminals 16a, 16b, and 16c correspondingly. The power cord 17 is made of a bundle of two power wires 17a, 17b and a ground wire 17c, and is integrally molded with flexible resin. The filter coil 18 is as shown in FIG. 2, and is made of a winding wire 18 made of a single copper wire coated with an insulating film.
a and 18b are attached to the same ferrite core 18d in the same direction.
It is wound in turns, mounted on a printed circuit board 21, and connected to input side terminals A, B and output terminals A', B', respectively, by the printed circuit board and insulated wires coated with flexible resin. In addition, the winding wire 18 is an insulated wire 18c made of a plurality of thin wires bundled and coated with a flexible resin.
It is wound five turns around a ferrite core 18d in the same direction as a and 18b, and is connected straight between terminals c and c' without using the foil of the printed circuit board. In addition, as shown in FIG. 1, the input terminal C of the filter coil 18 is connected to the power cord 1.
7, and the terminal C' is connected to a metal case 20 that houses the frequency converter 13.

In the above configuration, the ground wire 18c is electromagnetically coupled to the power wires 18a and 18b through the ferrite core 18d, and the in-phase input signals cancel each other out, so that they are propagated from the frequency converter 13 to the metal case 20, and are transmitted to the power cord 17.
Due to the distributed capacitance between the internal power lines 17a, 17b and the ground line 17c, symmetrical components of conduction noise leaking to the power line 17a or 17b can be effectively removed.

According to experiments, simply placing a 700 to 1000 uH (micro-Henry) inductor as a ground inductor between the metal case 20 and the power cord 17 reduces conduction noise at a specific frequency between 20 MHz and 30 MHz, which is hardly eliminated. It has been confirmed that it can be reduced by as much as a decibel. In addition, the power line 18a and the power line 1
As 8b, a single copper wire coated with an insulating film is wrapped around the ferrite 18d and soldered to the printed circuit board, making it easy to fix the parts.
c is a flexible insulated wire wrapped around the ferrite core 18d without being soldered to the printed circuit board, so there is no risk of breakage due to cracks in the foil or cracks in the soldered part, ensuring continuity as a ground wire. It is safe to use. In the above embodiment, the same effect can be obtained even if the metal case 20 is made of resin and non-charged metal parts such as the internal chassis on which the parts are placed are grounded by the ground wire 17c.

Next, other embodiments will be described. The induction heating cooker shown in FIG. 3 is a built-in type, and the exterior case includes a metal heating coil case 22 that stores the heating coil 12, and a metal main body case 2 that stores the frequency converter 13.
It is divided into 3. A top plate 24 made of ceramic on which a load pan is placed on the top of the heating coil 12 is held between the upper circumference of the heating coil case 22. The heating coil case 22 is dropped into an opening made in a worktop 25 of a stainless steel sink, and is held in contact with the worktop 25 at the peripheral edges. The main body case 23 is placed on a wooden shelf 27 provided horizontally inside a wooden side wall 26 that supports a worktop 25, and is provided with a filter coil 18 shown in FIG. Power supply line 17a molded inside.

17b and a ground wire 17c connected to the main body case 23 are electromagnetically coupled to each other so as to cancel in-phase currents. Further, the heating coil case 22 and the main body case 23 are connected by a conductive wire 28, and an inductance element 29 made of ferrite beads or the like for removing high frequency noise is connected to the conductive wire 28.

In the above configuration, the frequency converter 13 is composed of components such as a switching semiconductor, a resonant capacitor, or a filter capacitor, and is an OF of a switching transistor.
Since steep currents with large peak currents associated with F and ON flow, noise components of 20 MHz or higher are radiated, but they are not radiated to the outside because they are shielded by the metal main body case 23. Also, for safety reasons, it is grounded to the earth by a ground wire 17c, but since there is a filter coil 18, high frequency noise induced into the metal case 23 by radiation noise from the frequency converter 13 as described in the first embodiment. It is possible to prevent noise from leaking into the power line as conduction noise via the distributed capacitance between the power lines 17a, 17b and the ground line 17c inside the power cable. On the other hand, since the heating coil 12 is an inductance element, discontinuous current generally does not flow, and the amount of radiation of high frequency noise components of 20 MHz or higher is relatively small.
Even if the heating coil case 22 is made of metal, the amount of noise of such a frequency induced therein is small.
The level of high frequency noise leaking to the ground via the ground is low. Furthermore, for safety, the heating coil case 22 and the grounded main body case 23 are connected by a conductive wire 28, but since an inductance element 29 for removing high frequency noise is provided between the conductive wires, the main body The high frequency noise superimposed on the case 23 damages the conductive wire 28 and the heating coil case 22.
It can reduce leakage to the ground via.

Furthermore, in FIG. 3, by constructing the heating coil case 22 with an insulating material such as resin, it is possible to prevent high frequency noise from leaking from the worktop 25 to the ground, and the conductive wire 28 or inductance element 29 can be omitted. In addition, since the weight of the heating coil case 22 is reduced, it is possible to reduce deflection of the opening of the worktop 25 made of thin stainless steel or the like, and at the same time, the worktop 25 of the heating coil case 22 can be The structure can be simplified because the holding strength of the abutting part can be weakened.

Furthermore, another embodiment will be described with reference to FIG. In this figure, parts corresponding to those in FIG. 3 are given the same reference numerals. The main body case 23 is made of metal and houses the frequency converter 13 and the filter coil 18 shown in FIG. Both are connected by screws and placed on a wooden [27]. In addition, the connecting plates 30 and 31 are provided with a plurality of mounting holes or elongated mounting holes, so that the mounting height of the heating coil case 22 can be adjusted to match the surfaces of the worktop 25 and the mounting plate 24 to appropriate heights. can be adjusted. The ceramic top plate 24 is fixed to the upper local flange of the heating coil case 22 on the back surface at a distance of about 20 mm from the periphery with adhesive, and is also attached to a step provided on the stainless steel worktop 25. It is fitted into a certain opening and the periphery is sealed with a sealant.

In the above configuration, even though the heating coil case 22 is made of a metal material and is connected to the main body case 23 on which a lot of high frequency noise is superimposed by the conductive connecting plate 30, 31, the grounded stainless steel worktop 25, Since a predetermined distance can be maintained between the heating coil case 22 and the heating coil case 22, there is no risk of noise from the frequency converter 13 leaking from the worktop 25 to the ground.
Filter coil 18 (not shown in Figure 4)
, it is possible to suppress high frequency conduction noise leaking into the power line via the distributed capacitance between the ground wire of the power cable 17 and the power source.

Effects of the Invention As is clear from the embodiments described above, according to the present invention, a case made of a conductive material that houses or fixes a frequency converter or an internal non-charged metal component and a ground wire connecting the earth, and a commercial power supply The power line connecting the frequency converter is magnetically coupled so that currents in the same phase cancel each other out, so it is difficult to remove the power line from the metal case or chassis by simply inserting a ground coil into the ground line. Asymmetric conduction noise components leaking to the power supply line via the distributed capacitance of the ground line can be effectively removed by the canceling effect, and the influence of conduction noise on other electronic devices can be easily reduced. In addition, even if the number of turns of the ground wire and power wire wound around the magnetic coupler is small, a considerable reduction effect can be obtained, so even if the diameter of these wires is increased, the shape of the magnetic coupler will not become larger, and therefore, this magnetic The combination is easy to install in equipment, and even if the live part of the frequency converter accidentally touches the metal case or metal chassis, there is no risk of breaking the ground wire or increasing the temperature of the winding, so it is safe.

The present invention also provides a first external casing made of a conductive material that houses the heating coil and comes into contact with the worktop, and a second external casing made of a conductive material that houses the frequency conversion device, The external casing and the second external casing or the internal non-current metal parts that fix the frequency converter are connected by a conductive wire, and the latter, that is, the second external casing or the internal non-current metal parts are grounded. Even if a live part of an electrical component comes into contact with it in an accident, the user or repair person can be prevented from receiving an electric shock. Furthermore, since an inductance element is connected to the conductive wire, high-frequency noise superimposed on the second external casing housing the frequency converter, which emits a large amount of high-frequency electromagnetic waves, passes through the conductive wire. leaks into the first external casing, and then leaks to the ground as conductive noise via the conductive worktop that this first external casing touches, causing interference with other grounded electronic devices. noise interference can be suppressed. In addition, the ground wire and power supply wire are magnetically coupled so that the in-phase currents flowing through each wire generate an electromotive force that cancels each other's currents, so the frequency converter can be housed by the electromagnetic waves generated by the frequency converter. Asymmetrical components of high frequency conduction noise induced between the ground and non-current metal parts, such as the metal case or the internal chassis to which the frequency converter is fixed, are effectively filtered out from the ground wire. Therefore, conduction noise leaking from the first external housing to the power line via the distributed capacitance between the ground line and the power line bundled close to this ground line over 1 to 2 meters within the power cable is reduced. Can be reduced. As mentioned above, when using an induction heating cooker built into a worktop, regardless of whether the worktop is conductive or not, from the frequency converter to the conductive casing or internal chassis that houses it, It is possible to effectively suppress conduction noise that leaks to the power supply line or the ground through the ground line or worktop.

Furthermore, in the present invention, the external casing that houses the frequency converter or the heating coil is made of a conductive material that is grounded by a ground wire, so even if an electrical component touches the casing in an accident, the user or repair person can It is safe and there is no risk of electric shock.

In addition, the upper side wall of the external casing is fixed to the mounting plate at a predetermined distance inward from the periphery of the back surface of the mounting plate of the insulating pot to be heated, and the periphery of the mounting plate is brought into contact with the worktop. Since it is in contact with the worktop, it is possible to maintain a predetermined distance from the worktop. Therefore, the high-frequency noise superimposed on the conductive external casing housing the frequency converter, which emits a large amount of high-frequency electromagnetic waves, becomes conductive noise via the conductive worktop that comes into contact with the external casing. It is possible to prevent noise from leaking into the ground and causing noise interference to other grounded electronic devices. In addition, the ground wire and power wire are magnetically coupled so that the in-phase currents flowing through each wire generate an electromotive force that cancels each other's currents, so the frequency converter can be housed by the electromagnetic waves generated by the frequency converter. Asymmetrical components of high frequency conducted noise induced between the metal case and the ground are effectively filtered out of the ground wire. Therefore, conduction noise leaking from the first external casing to the power line via the distributed capacitance between the ground line and the power line bundled close to this ground line over 1 to 2 meters within the power cable is reduced. It can be suppressed. As mentioned above, when using an induction heating cooker built into a worktop, regardless of whether the worktop is conductive or not, there is a need to connect the ground wire or It is possible to effectively suppress conduction noise that leaks through the worktop to the power line and the ground.

The present invention also provides a first external casing made of an insulating material that houses the heating coil and comes into contact with the worktop, and a second external casing made of a conductive material that houses the frequency converter or fixes the frequency converter. Since the second external casing or the internal non-current metal parts are grounded, the user or the person in charge of repair can be prevented from receiving an electric shock even if the live part of the electrical part comes into contact with it in an accident. I can do it. Also,
Since the first external casing is made of an insulating material, high-frequency noise superimposed on the second external casing housing the frequency converter that emits a large amount of high-frequency electromagnetic waves is transmitted to the first external casing. There is no leakage to the casing due to conduction, and when this first external casing is assembled into a worktop, even if the contacting workpiece knob is conductive and is grounded, there will be no leakage through this worktop. High frequency noise will not leak to the ground as conduction noise and cause noise interference to other grounded electronic equipment. In addition, the ground wire and power wire are magnetically coupled so that the in-phase currents flowing through each wire generate an electromotive force that cancels each other's currents, so the electromagnetic waves generated by the frequency converter can be used to store or store the frequency converter. Asymmetrical components of high frequency conduction noise induced between the fixed second external casing or internal non-current metal parts and the ground are effectively removed from the ground wire. Therefore, conduction noise that leaks from the second external casing to the power line via the distributed capacitance between the ground wire and the power line bundled close to this ground line over 1 to 2 meters within the power cable is reduced. Can be reduced. As mentioned above, when using an induction heating cooker built into a worktop, regardless of whether the worktop is conductive or not, from the frequency converter to the conductive casing or internal chassis that houses it, It is possible to effectively suppress conduction noise that leaks to the power line or the ground through the ground wire or worktop, and
- Since the first external casing is made of an insulating material, the weight can be reduced, and the amount of deflection due to the weight of the worktop equipment can be reduced when it is incorporated into a worktop with a thin film thickness.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram of an induction heating cooker according to an embodiment of the present invention, Fig. 2 is an external perspective view showing a magnetic coupling body of the power supply line and ground line, and Figs. 5 and 6 are circuit block diagrams showing a filter structure of a conventional induction heating cooker. 12-m-induction heating coil, 13-m-frequency converter, 14-11 commercial power supply, 17a, 17b--1 power line,
17cm--ground wire, 19-m-ground, 20-m-metal case, 22-11 first external casing, 3-11 second external casing, m-mounting plate.

Claims (4)

[Claims] (1) An induction heating coil, a frequency converter that converts a commercial power source into a high-frequency current and supplies this high-frequency current to the induction heating coil, and a conductive material that is grounded to the earth by a ground wire and houses or fixes the frequency converter. or an internal non-charged metal part, the in-phase currents flowing through the power line and the ground line arranged between the commercial power source and the frequency converter cancel each other's currents. An induction heating cooker that is magnetically coupled to generate an electromotive force. (2) an induction heating coil; a first external casing made of a conductive material that houses the induction heating coil and contacts the worktop; and a first external casing that converts a commercial power source into a high-frequency current and supplies the high-frequency current to the induction heating coil. A frequency conversion device that supplies
a second external casing or an internal non-charged metal part made of a conductive material that is grounded to the earth by a ground wire and houses or fixes the frequency converter, and a power line disposed between the commercial power source and the frequency converter; a magnetic coupling member that generates an electromotive force that causes in-phase currents flowing through each of the ground wires to cancel each other's currents; and a conductive material portion of the first external casing and the second external casing or the non-conductive material portion of the first external casing and the second external casing. An induction heating cooker consisting of an inductance element installed in a conductive wire that electrically connects charged metal parts. (3) An induction heating coil, a frequency converter that converts a commercial power supply into a high frequency current and supplies this high frequency current to the induction heating coil, and a worktop with an insulating property on which a pot to be heated is placed and a worktop on the periphery. and a side wall that houses the frequency converter or the heating coil and is grounded to the earth by a ground wire, and is placed on the back side of the mounting plate at a predetermined distance inward from the periphery of the mounting plate. An external casing made of a conductive material whose upper part is fixed, and a power supply line disposed between the commercial power supply and the frequency converter, and a power supply line and a ground line, each of which causes in-phase currents to cancel each other's currents. An induction heating cooker consisting of a magnetic coupling body that generates electric power. (4) an induction heating coil; a first external casing made of an insulating material that houses the induction heating coil and contacts the worktop; converts a commercial power supply into high-frequency current and supplies this high-frequency current to the induction heating coil; a frequency conversion device that
a second external casing or internal non-charged metal parts made of a conductive material that is grounded to the earth by a ground wire and houses or fixes the frequency converter, and a power supply line disposed between the commercial power source and the frequency converter; An induction heating cooker comprising a magnetic coupling body in which in-phase currents flowing through each of the ground wires generate an electromotive force that cancels each other's currents.