JP2006221951A5 - - Google Patents

Description

Induction heating device

  The present invention relates to an induction heating device such as an electromagnetic cooker that heats an object to be heated by using induction heating by a high frequency magnetic field.

  Conventionally, in this type of induction heating apparatus, a method of reducing a 20 k to 50 kHz high frequency leakage magnetic field leaking from the heating coil by arranging an electromagnetic shield ring on the outer peripheral portion of the heating coil is known (for example, Patent Documents). 1). This is because the induction current flows in the electromagnetic shield ring due to the leaked magnetic field that is not absorbed by the object to be heated among the high-frequency magnetic field generated in the heating coil, and the induction current flowing through the electromagnetic shield ring causes the high-frequency in the direction opposite to that of the heating coil. A magnetic field is generated in the electromagnetic shield ring, and as a result, the high-frequency leakage magnetic field from the heating coil and the high-frequency magnetic field from the electromagnetic shield ring act to cancel each other. As the electromagnetic shield ring, an aluminum shield or a lead wire is used so that an induced current flows through itself.

In addition, an inductance is formed by winding the vicinity of the outer periphery of the heating coil, and the heating coil and the inductance are arranged in a direction in which the high-frequency magnetic field generated from the heating coil and the high-frequency magnetic field component generated from the inductance cancel each other. It is known (see, for example, Patent Document 2). In this configuration, the inductance is composed only of windings, and the core material for the inductance is not required, so that the apparatus can be miniaturized and has the effect of reducing high frequency noise.
JP-A-57-115795 Japanese Patent Publication No. 63-7672

  However, in the configuration in which the conventional electromagnetic shield ring is arranged, the high-frequency leakage magnetic field can be reduced by the effect of the electromagnetic shield ring, but the power frequency generated from the heating coil or the magnetic field twice the frequency of the power source (hereinafter referred to as the magnetic field) The low frequency magnetic field is not absorbed by the object to be heated and released to the outside, and the electromagnetic shield ring cannot generate a reverse magnetic field that only cancels the low frequency magnetic field, so the low frequency magnetic field does not decrease. As a result, there is a problem of being released outside the device.

  Further, in the case of the conventional inductance, the number of turns of the winding increases because the winding is operated as an inductance (about several hundred μH). At this time, the low-frequency magnetic field emitted from the winding becomes larger than the low-frequency magnetic field emitted from the heating coil, resulting in an increase in the low-frequency magnetic field emitted to the outside.

  The present invention solves the above-described conventional problems, and provides an induction heating device that reduces the emission of a low-frequency magnetic field from a heating coil with a simple configuration and reduces unnecessary electromagnetic waves generated from equipment. With the goal.

In order to solve the conventional problems, an induction heating apparatus according to the present invention includes a heating coil that generates a high-frequency magnetic field for induction heating of an object to be heated, a heating coil base that holds the heating coil, and a power supply unit. The rectifying means for rectifying the power of the connected commercial frequency and converting it to a power having a low frequency component of twice the commercial frequency, converting the power having the low frequency component to a high frequency power, and the heating coil wherein a high-frequency oscillation section for supplying a high-frequency current low frequency component and high frequency component is superimposed, said a power supply unit for supplying electric power of a commercial frequency to a high frequency oscillator unit, the heating coil base at an outer peripheral portion of the heating coil on top of the is composed of the inductor wiring in the high-frequency oscillation unit, has the same frequency components as the low-frequency component flowing through the heating coil, the low-frequency magnetic field generated from the heating coil each other A concave groove current in the opposite direction to place the coiled wire that flows so as to cancel the provided one in which the coiled wire disposed in the concave groove.

  As a result, the magnetic field generated from the coil-shaped wiring in which the current flows in the opposite direction to the heating coil with the same frequency component as the low-frequency component of the current flowing in the heating coil and the low-frequency leakage magnetic field generated from the heating coil cancel each other. In addition, the low-frequency leakage magnetic field is greatly reduced, and the coil-shaped wiring is arranged on the heating coil base, so that it is not necessary to prepare a new member for storing the coil-shaped wiring. A low frequency leakage magnetic field can be reduced with a simple configuration.

  The induction heating device of the present invention can reduce a low-frequency leakage magnetic field generated from a heating coil with an inexpensive and simple configuration.

In a first aspect of the present invention, a heating coil that generates a high-frequency magnetic field for inductively heating an object to be heated, a heating coil base that holds the heating coil, and a power supply unit that rectifies the power of the commercial frequency and A rectifying means for converting the electric power having a low frequency component of twice the frequency, converting the electric power having the low frequency component into high frequency electric power, and superposing the low frequency component and the high frequency component on the heating coil; a high-frequency oscillation unit for supplying a current, a the high-frequency oscillating unit power supply unit for supplying electric power of a commercial frequency, the on of the heating coil base at the outer peripheral portion of the heating coil, the inductor in the high-frequency oscillation unit consists of wire, carp wherein has the same frequency components as the low-frequency component flows through the heating coil, a current flows in opposite directions so that the low-frequency magnetic field generated from the heating coil cancel each other A concave groove to place Jo wiring provided, by arranging the coiled wire in the concave groove, it is not necessary to newly prepare a member for storing the coiled wire, Low frequency leakage magnetic field can be reduced with an inexpensive and simple configuration.

In addition, the heating coil base is provided with a recess for arranging the coil-shaped wiring on the outer peripheral portion, so that the shape of the coil-shaped wiring is easily secured, and the coil-shaped wiring does not cause a position shift or the like. The low frequency leakage magnetic field can be reduced with an inexpensive and simple configuration.

According to a second aspect of the present invention, in particular, in the first aspect of the present invention, the heating coil base is provided with an electromagnetic shield ring that cancels a high-frequency leakage magnetic field generated from the heating coil together with the coil-shaped wiring in the recess. Since components for reducing the low-frequency and high-frequency leakage magnetic fields can be placed at the same location above, the configuration of the heating coil base can be made thin and compact.

According to a third aspect of the present invention, there is provided a heating coil that generates a high-frequency magnetic field for inductively heating an object to be heated, a heating coil base that holds the heating coil, and a power source unit that rectifies commercial frequency power to A rectifying means for converting the electric power having a low frequency component of twice the frequency, converting the electric power having the low frequency component into high frequency electric power, and superposing the low frequency component and the high frequency component on the heating coil; A high-frequency oscillating unit for supplying current; and a power supply unit for supplying commercial-frequency power to the high-frequency oscillating unit, and wiring of an inductor in the high-frequency oscillating unit on a side surface of the heating coil base at an outer peripheral portion of the heating coil in the configuration, carp wherein has the same frequency components as the low-frequency component flows through the heating coil, a current flows in opposite directions so that the low-frequency magnetic field generated from the heating coil cancel each other Since it is not necessary to prepare a new member for storing the coil-shaped wiring by wrapping and arranging the shaped wiring, the low frequency leakage magnetic field can be reduced with an inexpensive and simple configuration, Since the coil-like wiring is arranged in tandem, it is not necessary to increase the diameter of the heating coil base, and a compact configuration can be taken.

According to a fourth aspect of the invention, in particular, in the third aspect of the invention, the heating coil base is provided with a groove for winding the coil-shaped wiring on its side surface, so that the installation property of the coil-shaped wiring is improved. It is possible to obtain a structure with good workability when forming a wiring having a shape.

According to a fifth aspect of the present invention, there is provided a heating coil that generates a high-frequency magnetic field for induction heating of an object to be heated, a heating coil base that holds the heating coil, and a commercial frequency connected to a power supply unit to rectify the power of the commercial frequency. A rectifying means for converting the electric power having a low frequency component of twice the frequency, converting the electric power having the low frequency component into high frequency electric power, and superposing the low frequency component and the high frequency component on the heating coil; A high-frequency oscillating unit that supplies current; a power source unit that supplies commercial frequency power to the high-frequency oscillating unit; and an electromagnetic shield ring that cancels a high-frequency leakage magnetic field generated from the heating coil on the outer periphery of the heating coil , wherein a side surface of the electromagnetic shield ring consists of an inductor of the wiring in the high-frequency oscillating unit, it has the same frequency components as the low-frequency component flowing through the heating coil, heating coil By using an induction heating device with coiled wiring through which current flows in the opposite direction so that the generated low frequency magnetic fields cancel each other, it is possible to place components that reduce the low frequency and high frequency leakage magnetic fields in the electromagnetic shield ring. Therefore, almost no new member or space for coiled wiring is required, and the leakage magnetic field can be reduced with an inexpensive and simple configuration.

According to a sixth aspect of the invention, in particular, in the fifth aspect of the invention, the electromagnetic shield ring is arranged in a ring shape with an L-shaped cross section so that the position of the coiled wiring can be determined reliably. In addition, since the coiled wiring can be fixed with a simple configuration, the low-frequency leakage magnetic field can be reduced with a low-cost and simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 to 3 show an induction heating apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the induction heating apparatus according to the present embodiment is generated from a heating coil 1 that generates a high-frequency magnetic field for induction heating an object to be heated 15 such as a pan or a frying pan, and the heating coil 1. The electromagnetic shield ring 2 that cancels the high-frequency leakage magnetic field, the heating coil base 16 that holds the heating coil 1, the high-frequency oscillation unit 11 that supplies a high-frequency current to the heating coil 1, and commercial frequency power to the high-frequency oscillation unit 11 And a power supply unit 3 to be supplied.

  The heating coil base 16 holds the heating coil 1 on the heating coil base 16, and a magnetic-shielding ferrite 13 that enhances magnetic coupling with the object to be heated 15 is disposed below the heating coil base 16. The high-frequency oscillator 11 includes a rectifier 4 connected to the power supply unit 3, a series connection of an inductance 5 and a smoothing capacitor 6 connected in series with the rectifier 4, and a resonance connected in parallel to the smoothing capacitor 6. The capacitor 7 and the semiconductor switch 8 are connected in series, and the resonance capacitor 7 is connected in parallel with the heating coil 1.

  On the other hand, the wiring of the inductance 5 has the same frequency component as the low frequency component of the current flowing in the heating coil 1 and the coiled wiring 12 in which current flows in the opposite direction to the heating coil 1 (opposite to the winding direction of the heating coil 1). Coil-shaped wiring wound a plurality of times. The coil-shaped wiring 12 is disposed on the heating coil base 16 at the outer periphery of the heating coil 1.

  In the present embodiment, a general circuit configuration used for the induction heating apparatus is shown, but there is no particular limitation as long as the circuit configuration generates a low-frequency magnetic field from the heating coil 1.

  Next, operation | movement of the induction heating apparatus in this Embodiment is demonstrated.

  FIG. 2 shows a current waveform in each section of the inverter circuit. I3 indicates an input current, I5 indicates a current flowing through the inductance 5 and the coiled wiring 12, and I11 indicates a current flowing through the heating coil 1. The power supply unit 3 includes a commercial power source and a filter, and supplies commercial frequency power to the high-frequency oscillation unit 11. Therefore, the input current I3 is a current having a commercial frequency component. In the high-frequency oscillating unit 11, the commercial power is rectified by the rectifying means 4 to be converted into power having a frequency component twice that of the commercial power supply, and further converted into high-frequency power of about 20 k to 50 kHz using the semiconductor switch 8. The high-frequency power is supplied to the heating coil 1 and is supplied from the heating coil 1 to the object to be heated 15 in the form of a high-frequency magnetic field. The object to be heated 15 generates an eddy current in the surface layer portion due to the high-frequency magnetic field, and as a result, generates heat. Therefore, the current I5 that is twice the commercial frequency flows through the inductance 5 and the coiled wiring 12, and when the semiconductor switch 8 becomes conductive in the heating coil 1, the power supply unit 3 A current I11 in which a low-frequency current having a component twice the commercial frequency generated in the loop of the rectifier 4 → the heating coil 1 → the semiconductor switch 8 and a high-frequency component flowing in the heating coil 1 according to the frequency of the semiconductor switch 8 flows. .

  And it arrange | positions mutually so that the low frequency magnetic field of the heating coil 1 and the coil-shaped wiring 12 may mutually cancel, The low frequency magnetic field which generate | occur | produces from the heating coil 1 can be canceled. At this time, if the coil-shaped wiring 12 is in the vicinity of the outer peripheral portion of the heating coil 1, the cancellation effect is large.

  Moreover, since the heating coil 1 generates heat due to its own resistance component during operation, forced cooling by a cooling fan or the like is necessary, and it is desirable that the coiled wiring 12 does not hinder this cooling air. Therefore, as shown in FIG. 3, the groove 16a is provided on the outer periphery of the outermost periphery of the heating coil on the heating coil base 16, and the coil-shaped wiring 12 is disposed in the groove 16a, thereby cooling air to the heating coil 1. The low frequency magnetic field from the heating coil 1 can be reduced without hindering. Furthermore, since the coil-shaped wiring 12 is formed on the heating coil base 16, no additional member is generated, so that an inexpensive configuration can be taken.

  On the other hand, the coil-shaped wiring 12 has an effect of canceling out the low-frequency magnetic field, but is less effective for a high-frequency leakage magnetic field of 20 to 50 kHz that performs induction heating of the article 15 to be heated. For this reason, it is necessary to generate an induced current in the electromagnetic shield ring 2 by arranging the electromagnetic shield ring 2 made of aluminum or the like in the vicinity of the heating coil 1 and to cancel the leakage magnetic field by the canceling magnetic field due to the induced current. It becomes. At this time, as shown in FIG. 3, by installing the electromagnetic shield ring 2 in the groove 16 a in which the coil-shaped wiring 12 is disposed, the constituent elements constituting the unit of the heating coil 1 are incorporated on the heating coil base 16. Therefore, a compact configuration can be taken.

  As described above, in the present embodiment, by arranging the coiled wiring 12 on the heating coil base 16 on the outer periphery of the heating coil 1, the low frequency of the current flowing in the heating coil 1 that is in the high frequency oscillation unit 11. The magnetic field generated from the coil-shaped wiring 12 arranged so that the current flows in the opposite direction to the heating coil 1 with the same frequency component as the component and the low-frequency leakage magnetic field generated from the heating coil 1 cancel each other, and the low frequency The leakage magnetic field is greatly reduced, and the coil-shaped wiring 12 is arranged on the heating coil base 16, so that it is not necessary to prepare a new member for storing the coil-shaped wiring 12, so that it is inexpensive and simple. Can be configured.

(Embodiment 2)
FIG. 4 shows an induction heating apparatus according to Embodiment 2 of the present invention. The same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The present embodiment is different from the first embodiment in that coil-shaped wirings 12 are wound around the side surface of the heating coil base 16 so as to be arranged in a column.

  This is because, in the case where the coil-shaped wiring 12 is provided in addition to the outermost periphery of the heating coil 1 as in the first embodiment, the diameter of the heating coil base is increased, thereby limiting the outer diameter of the casing. In some cases, the shape of the heating coil 1 is prevented from being reduced. By making the shape of the heating coil 1 large as described above, the temperature distribution of the object to be heated 15 can be improved when the shape of the object to be heated 15 is large. Usually, since the heating coil base 16 has the heating coil 1 at the top and the magnetic-shielding ferrite 13 at the bottom, the thickness of the side surface of the heating coil base 16 is around 20 mm. For this reason, the components on the heating coil base 16 can be accommodated in a more compact configuration by utilizing this side surface.

  The heating coil base 16 is provided with a groove (not shown) for winding the coiled wiring 12 on the side surface, so that the coiled wiring 12 can be accommodated in a compact manner.

  As described above, in the present embodiment, a member for storing the coiled wiring 12 is newly prepared by arranging the coiled wiring 12 around the side surface of the heating coil base 16. Therefore, it is possible to reduce the low-frequency leakage magnetic field with an inexpensive and simple configuration, and the coil-shaped wirings 12 are arranged in tandem. Therefore, it is necessary to increase the diameter of the heating coil base 16. And a compact configuration.

(Embodiment 3)
5 and 6 show an induction heating apparatus according to Embodiment 3 of the present invention. The same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the difference from the first embodiment is that the outer periphery of the heating coil 1 includes an electromagnetic shield ring 2 that cancels a high-frequency leakage magnetic field generated from the heating coil 1. The coil-shaped wiring 12 having the same frequency component as the low-frequency component of the current flowing in the heating coil 1 and flowing in the opposite direction to the heating coil 1 is wound and arranged.

  By adopting the above configuration, a winding jig for winding the coiled wiring 12 is not required, so that an inexpensive magnetic shield configuration can be taken. Further, since the electromagnetic shield ring 2 and the coiled wiring 12 can be disposed in the vicinity of the outer peripheral portion of the heating coil 1, it becomes possible to cancel out more leakage magnetic fields generated from the heating coil 1.

  As shown in FIG. 6, the electromagnetic shield ring 2 has a ring shape with an L-shaped cross section, and the coil-shaped wiring 12 is disposed in the L-shaped portion, so that the installation position of the coil-shaped wiring 12 can be stabilized. Can be made.

  As described above, in the present embodiment, a part that reduces the low-frequency and high-frequency leakage magnetic fields is placed on the electromagnetic shield ring 2 by arranging the coil-shaped wiring 12 around the side surface of the electromagnetic shield ring 2. Therefore, almost no new member or space for the coiled wiring 12 is required, and the leakage magnetic field can be reduced with an inexpensive and simple configuration.

(Embodiment 4)
FIG. 7 shows an induction heating apparatus according to Embodiment 4 of the present invention. The same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The present embodiment is different from the first embodiment in that an electromagnetic shield ring 2 for canceling a high-frequency leakage magnetic field generated from the heating coil 1 is provided on the outer periphery of the heating coil 1 on the heating coil base 16. The ring 2 has a ring shape with a concave cross section in which the coil-shaped wiring 12 is disposed.

  With the above configuration, the coil-shaped wiring 12 can be disposed inside the concave section 2a having a concave cross section of the electromagnetic shield ring 2, and the coil-shaped wiring 12 can be easily and stably formed on the heating coil base 16. Can be placed while keeping. This eliminates the need for a component for stabilizing the shape of the coiled wiring 12, thereby making it possible to adopt an inexpensive magnetic shielding configuration and to reliably determine the position of the coiled wiring 12. It can be stabilized.

  As described above, in the present embodiment, the electromagnetic shield ring 2 is formed in a ring shape having a concave cross section in order to dispose the coil-shaped wiring 12, so that the position of the coil-shaped wiring can be determined reliably. Since the canceling effect on the leakage magnetic field can be stabilized, the low-frequency leakage magnetic field can be reduced with an inexpensive and simple configuration.

  As described above, the induction heating device according to the present invention can reduce the low-frequency leakage magnetic field generated from the heating coil with an inexpensive and simple configuration, and thus can be applied to an electromagnetic cooker or the like.

The block diagram of the induction heating apparatus in Embodiment 1 of this invention Current waveform diagram in each part of the induction heating device Sectional drawing which shows the principal part structure of the same induction heating apparatus The block diagram of the induction heating apparatus in Embodiment 2 of this invention The block diagram of the induction heating apparatus in Embodiment 3 of this invention Sectional drawing which shows the principal part structure of the same induction heating apparatus Sectional drawing which shows the principal part structure of the induction heating apparatus in Embodiment 4 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating coil 2 Electromagnetic shield ring 2a Recess 3 Power supply part 11 High frequency oscillation part 12 Coiled wiring 15 Object to be heated 16 Heating coil base 16a Groove

Claims (6)

A heating coil that generates a high-frequency magnetic field for inductively heating an object to be heated, a heating coil base that holds the heating coil, and a power supply unit that rectifies commercial frequency power and has a frequency that is twice that of the commercial frequency. High-frequency oscillation having a rectifying means for converting to electric power having a frequency component, converting the electric power having the low-frequency component into high-frequency electric power, and supplying a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil and parts, and a said high-frequency oscillating unit power supply unit for supplying electric power of a commercial frequency, the on of the heating coil base at the outer peripheral portion of the heating coil is constituted by the inductor wiring in the high-frequency oscillation unit, the Coiled wiring that has the same frequency component as the low-frequency component flowing in the heating coil and in which current flows in the opposite direction is arranged so that the low-frequency magnetic fields generated by the heating coil cancel each other. Induction heating device the provided concave grooves were arranged the coiled wire in the concave grooves. Heating coil base, induction heating apparatus according to claim 1 wherein placing the electromagnetic shield ring that cancels the leakage magnetic field of a high frequency generated from the heating coil together with the coil-shaped wiring in the recess. A heating coil that generates a high-frequency magnetic field for inductively heating an object to be heated, a heating coil base that holds the heating coil, and a power supply unit that rectifies commercial frequency power and has a frequency that is twice that of the commercial frequency. High-frequency oscillation having a rectifying means for converting to electric power having a frequency component, converting the electric power having the low-frequency component into high-frequency electric power, and supplying a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil And a power supply unit that supplies commercial frequency power to the high-frequency oscillation unit, and includes a wiring of an inductor in the high-frequency oscillation unit on a side surface of the heating coil base at an outer peripheral portion of the heating coil, It has the same frequency components as the low-frequency component passing through the coil, winding the wire coiled current flows in opposite directions so that the low-frequency magnetic field generated from the heating coil cancel each other Give arranged induction heating device. The induction heating apparatus according to claim 3 , wherein the heating coil base is provided with a groove for winding a coil-shaped wiring on a side surface. A heating coil that generates a high-frequency magnetic field for inductively heating an object to be heated, a heating coil base that holds the heating coil, and a power supply unit that rectifies commercial frequency power and has a frequency that is twice that of the commercial frequency. High-frequency oscillation having a rectifying means for converting to electric power having a frequency component, converting the electric power having the low-frequency component into high-frequency electric power, and supplying a high-frequency current in which the low-frequency component and the high-frequency component are superimposed on the heating coil A power supply unit for supplying commercial frequency power to the high-frequency oscillation unit, and an electromagnetic shield ring for canceling a high-frequency leakage magnetic field generated from the heating coil on the outer periphery of the heating coil, and a side surface of the electromagnetic shield ring It is composed of the inductor wiring in the high-frequency oscillation unit to have the same frequency component as the low frequency component flowing through the heating coil, low frequency generated from the heating coil Induction heating apparatus in which the magnetic field is arranged coiled wire current flows in opposite directions to cancel each other. The induction heating device according to claim 5 , wherein the electromagnetic shield ring has a coil-shaped wiring arranged as a ring shape having an L-shaped cross section.