JP4915186B2 - Cooker - Google Patents

Description

  The present invention relates to a cooking device used in general homes, restaurants and offices.

Conventionally, the heating output of the resistance load is varied by opening and closing the relays connected to both ends of the resistance load (heater), and if one of the relays has a welding failure, the resistance load is opened by opening the other relay. 2. Description of the Related Art A resistance load driving device for an electric heater that prevents unintentional energization of the battery is known (see, for example, Patent Document 1).
Japanese Patent No. 2738146

  However, in the above-described conventional configuration, when an induction heating type or dielectric heating type heating unit is provided, when the heating unit is heated, the switching noise of the switching means, etc., is caused as conduction noise in the electric wiring lead. It is easy to influence the AC power supply by propagating the power. For this reason, it is common to reduce the influence on the AC power source by routing electrical wiring leads, mounting a noise filter circuit, and examining the filter configuration from the early stage of device development. However, in reality, there is a change in equipment specifications just before mass production and a change in wiring specifications to improve assembly and serviceability. It can happen that it cannot be obtained. In such cases, there are issues such as that it takes time to reduce conduction noise, and that the countermeasure increases the manufacturing cost of the equipment due to a major change in the filter configuration, re-reviewing the wiring specifications, etc., and the production schedule is upset. is there.

  In addition, since the relays at both ends of the resistive load are open when the resistive load is not heated, the resistive load itself and the metal parts of the electrical wiring leads that connect the relay and the resistive load become unstable potentials, causing conduction noise that is applied to the AC power supply. As a result, there is a problem that the conductive noise reduction performance changes due to a small difference in assembly of the resistance load, the length of the electrical wiring lead, and the routing.

  The present invention solves the above-described conventional problems, stabilizes the effect of switching noise of an induction heating type or dielectric heating type heating unit on an electrical wiring lead, and suppresses variation and deterioration in conduction noise reduction performance. An object is to provide a cooking device.

In order to solve the conventional problem, the cooking device of the present invention is configured such that one end of a first relay is connected to one end of a resistance load, and one end of a second relay is connected to the other end of the resistance load. Inductive heating system or dielectric heating system including a series body in which the other end of one relay and the other end of the second relay are connected to an AC power source, and switching means and a load coil connected to both ends of the series body The heating unit, welding detection means for detecting contact welding of the second relay, and driving the heating unit, and when energizing the resistance load, the first relay is driven to a conductive state, with varying the heating power of the resistive load by the conduction and non-conduction of said second relay, said the contact welding detection time of the second relay and a driving circuit for the first relay non-conductive, wherein the driving circuit, Serial at the time of driving the heating unit, in which pre-SL was by Uni configuration you the first relay to a conducting state by driving.

  This eliminates the uncertainties in the resistance load and electrical wiring lead potential with respect to the potential of the AC power supply even when the heating unit of the induction heating type or dielectric heating type is operating, thereby switching noise. Can stabilize the influence on the electrical wiring lead, and can suppress variation and deterioration of the conduction noise reduction performance.

  Moreover, the continuous energization state to the unintended resistance load by contact welding of the 2nd relay can be avoided.

In the first invention, one end of a first relay is connected to one end of a resistive load, and one end of a second relay is connected to the other end of the resistive load, and the other end of the first relay and the second relay A series body having the other end connected to an AC power source, an induction heating type or dielectric heating type heating unit including switching means and a load coil connected to both ends of the series body, and a contact of the second relay The welding detection means for detecting welding and the heating unit are driven , and when the resistance load is energized, the first relay is driven to be in a conductive state, and the second relay is turned on / off by the conduction / non-conduction of the second relay. with varying the heating power of the resistive load, the the second time contact welding detection of the relay and a driving circuit for the first relay non-conductive, wherein the drive circuit, when driving the front Stories heating unit , before Symbol first relay With heating cooker that by Uni configuration you in a conductive state by driving the uncertainty of the potential of the resistive load and the electric wiring leads for the potential of the AC power source, the heating portion of the induction heating or dielectric heating method Fixing even during operation eliminates the problem, stabilizes the effect of switching noise on the electrical wiring leads, and suppresses variation and deterioration of the conduction noise reduction performance.

Moreover, the includes a second welding detection means for detecting the contact welding of the relay, the second at the time of contact welding detection of the relay, by constructing such that the pre-Symbol first relay non-conductive, the The continuous energization state to the unintended resistance load by contact welding of 2 relays can be avoided.

A second invention is, in particular, in the first invention, by having a notifying means for notifying to that effect at the time of contact welding detection of the second relay, in order to contact the second relay is welded Since the user can recognize that the heating operation by the resistance load is stopped, the user can be encouraged to take appropriate measures such as contacting the manufacturer for repair.

A third invention is, in particular, in the first invention, has contacts abnormality detection means for the first relay the driving circuit Despite outputs a driving signal to detect this case of a non-conductive the first at the time of detecting the non-conduction of the relay, by which is configured to reduce or stop the heating output of the heating unit, operates a heating unit at maximum heating output contacts of the first relay being in the non-conducting state Therefore, it is possible to prevent the influence of the conduction noise on the AC power generated by the operation of the heating unit from exceeding a specified level.

A fourth invention is, in particular, in the third invention, by having a notifying means for notifying to that effect at the time of non-conduction detection of said first relay, there in the condition to contact of the first relay is brought into conduction Nevertheless, since it is not conducting, the user can recognize that the heating output by the heating unit is limited or the heating operation is stopped, so appropriate measures such as contacting the manufacturer for repair Can be encouraged.

A fifth invention is, in particular, in the first or third invention, has a count memory means for counting and storing the number of times of opening and closing of the second relay, closing stored in said count storage means When the number reaches a predetermined number, stops the heating of the resistive load, by constructing such that the first and the second relay in the non-conducting state, counting the number of times of opening and closing of the second relay Therefore, the first and second relays may be brought into a non-conducting state when reaching a predetermined number of times less than the number of times expected to be welded due to the contact durability limit of the second relay. It is possible to prevent overheating due to continuous energization of an unintended resistance load.

A sixth invention is particularly, in the fifth invention, by the opening and closing times stored in said count storage means having a notification means for notifying to that effect reaches a predetermined number of times, the second relay Since the user can recognize that the number of times of opening / closing has reached a predetermined value, the first and second relays are turned off and the energization of the resistive load is stopped, contact the manufacturer for repair. The user can be encouraged to take appropriate measures. In addition, the corresponding notification of the welding detection means and the contact abnormality detection means can be collectively performed by one notification means.

The fifth invention has a counting / storing means for counting and storing the number of times the second relay is opened / closed in the first or third invention, and the number of times of opening / closing stored in the counting / storing means. When the predetermined number of times is reached, the heating of the resistance load is stopped, and the first and second relays are set in a non-conductive state, thereby counting the number of times the second relay is opened and closed. Compared with a predetermined number of times that is preset to be less than the number of times that contact of the relay is expected to be welded, the first and second relays can be brought into a non-conductive state when this is reached, and an unintended resistance Overheating due to continuous energization of the load can be prevented.

A sixth invention is particularly, in the fifth invention, by the opening and closing times stored in the count-storage means having a notification means for notifying to that effect reaches a predetermined number of times, the second relay Since the user can recognize that the number of times of opening / closing has reached a predetermined value, the first and second relays are turned off and the energization of the resistive load is stopped, contact the manufacturer for repair. The user can be encouraged to take appropriate measures. In addition, the corresponding notification of the welding detection means and the contact abnormality detection means can be collectively performed by one notification means.

  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)
The figure shows a circuit block diagram of the heating cooker in the embodiment of the present invention.

  As shown in the figure, the cooking device includes an AC power source 1, a series body of first and second relays 3 and 4 connected to both ends of a resistance load (heater) 2, and the series body and the AC power source. 1 based on a signal obtained from an operating means 11 comprising a switching unit 5a and an induction heating type or dielectric heating type heating unit 5 including a switching coil 5a and a load coil 5b, and a switch, etc. The first and second relays 3 and 4 and the drive circuit 6 that drives the heating unit 5 are included.

  The welding detection means 7 monitors the conduction / non-conduction state of the second relay 4, and the contact abnormality detection means 8 monitors the conduction / non-conduction state of the first relay 3. The notification means 9 comprises a buzzer, a speaker, an LCD, or an LED, and outputs desired information as voice, characters, or figures. In addition, the count / storage means 10 counts the opening and closing of the second relay 4 as one time at any time, and when it accumulates and reaches a predetermined number of times, transmits it to the drive circuit 6.

  About the heating cooker comprised as mentioned above, the operation | movement and an effect | action are demonstrated.

When the user depresses a switch (not shown) of the operation means 11, a signal for starting the operation of the resistance load 2 or the heating unit 5 is sent to the drive circuit 6. In response to this, when the drive circuit 6 energizes the resistance load 2, the drive circuit 6 first drives the first relay 3 to close the contact of the first relay 3 to make it conductive. Thereafter, in the present embodiment, after about 2 seconds, the second relay 4 is driven to close the contact of the second relay 4 to make it conductive. As a result, the AC power supply 1 and the resistive load 2 become conductive, and energization of the resistive load 2 is started. The time of about 2 seconds is a time obtained by adding a margin to the time when the contact of the first relay 3 is completely contacted after bouncing or the like is completely completed.

  At this time, when the heating output of the resistance load 2 is varied, the contact of the second relay 4 is repeatedly conducted / non-conducted at a desired duty ratio. That is, power control to the resistive load 2 is executed only by the second relay 4, and the first relay 3 is not involved in power control. This is because stress on the contacts of the first relay 3 is not applied to the contacts of the second relay 4 without applying stress accompanying contact deterioration due to arcs during conduction / non-conduction. Because. As a result, the contact of the second relay 4 is larger than the maximum energizing current level of the resistive load 2 and has a current capacity capable of withstanding the stress at the time of opening and closing. However, the contact current capacity of the first relay 3 can be set to the maximum energization current level of the resistance load 2, and both the first relay 3 and the second relay 4 are prevented from becoming large or expensive. is doing.

  When the heating unit 5 is heated (in the case of the induction heating method), the drive circuit 6 first drives the first relay 3 to connect the contact of the first relay 3 as in the case of the resistive load 2. Close and turn on. Thereafter, in this embodiment, after about 2 seconds, the switching means 5a is turned on / off and a high frequency current is supplied to the load coil 5b, whereby a high frequency alternating current is applied to a metal load pan (not shown) to be heated. A magnetic field is applied, an eddy current is generated at the bottom of the load pan, and the load pan is induction-heated with the Joule heat.

  At this time, the first relay 3 is driven and the contact of the first relay 3 is closed to make it conductive. The first relay 3 is closed and the resistance load 2 on the contact side of the first relay 3 is connected. Since the connection point is the one-side potential of the AC power supply 1, the potential of the resistance load 2 itself and the electrical wiring lead that electrically connects the contact of the resistance load 2 and the first relay 3 can be determined and stabilized. To the AC power source 1 due to switching noise when the heating unit 5 is activated and the switching means 5a is turned on / off due to variations in the assembly position of the resistance load 2 to the wire and variations in the wiring / length of the electrical wiring leads. This is to suppress the influence of the conduction noise reduction performance.

  Generally, when the contact of the first relay 3 is opened and remains in a non-conductive state, the potentials of the resistance load 2 itself and the electrical wiring leads that electrically connect the contact of the resistance load 2 and the first relay 3 are uncertain. In addition, the level of conduction noise given to the AC power source 1 due to the unstable and the switching means 5a being turned on / off also varies in the assembly of the resistance load 2 and the electrical connection for electrically connecting the resistance load 2 and the first relay 3 contact. Since it fluctuates depending on the length of the wiring lead and the variation in routing, it is difficult to make the conduction noise emitted from the device constant, and the mass productivity of the device is significantly reduced.

  Further, the drive circuit 6 monitors the voltage on the connection side of the resistance load 2 to the second relay 4 obtained from the welding detection means 7 to match the output drive signal logic to the second relay 4. When the mismatch is determined and it is determined that welding is performed, heating of the resistance load 2 is stopped, the first relay 3 is turned off, and the unintended resistance load 2 due to contact welding of the second relay 4 In addition to avoiding a continuous energization state, the notification means 9 notifies the user of this state, and prompts the user to take appropriate measures such as contacting the manufacturer for repair.

Similarly, the drive circuit 6 monitors the voltage on the connection side with the first relay 3 of the resistive load 2 obtained from the contact abnormality detection means 8, and outputs the drive signal logic to the first relay 3 output. If the contact of the first relay 3 is determined not to be conductive even though the match / mismatch is determined and the conduction signal is output, the contact of the first relay 3 is not conductive. In the state, the heating unit 5 is not operated at the maximum heating output, or is stopped, and the influence of the conduction noise on the AC power supply 1 generated by the operation of the heating unit 5 is greater than when the first relay 3 is in the conductive state. It is possible to prevent the risk of exceeding the specified level and to notify the user that the state is in this state by the notification means 9 and to prompt the user to take appropriate measures such as contacting the manufacturer for repair.

  Furthermore, the number of times of opening and closing the second relay stored in the count / storage means 10 is less than the number of times that the second relay 4 is subjected to stress such as an arc when opening and closing and becomes a limit of durability and is expected to weld (this embodiment In this mode, the heating of the resistance load 2 is stopped and the first and second relays 3 and 4 are made non-conductive to prevent contact welding of the second relay 4 and this state is reached. It is possible to notify the user of the fact by the notifying means 9 and to prompt the appropriate measures such as contacting the manufacturer for repair. This is useful in terms of preventing contact welding of the second relay 4 when used in a harsher state than the usage frequency and usage environment of the resistance load 2 assumed by the manufacturer.

  The notification means 9 may correspond to the welding detection means 7, the contact abnormality detection means 8, and the count / storage means 10 individually. However, in this embodiment, an example is shown in which these are collectively notified by one notification means. Note that the notification may be made only for a part of the means, or may be made for all the means, and can be appropriately selected as necessary.

  As described above, according to the present embodiment, of the first and second relays 3 and 4 connected to both ends of the resistive load 2, the first relay 3 is closed during normal use, and the resistive load is 2 is connected to one end of the AC power source 1 and the potential of the resistive load 2 is fixed, so that the first and second relays 3 and 4 at both ends of the resistive load 2 are open, and the resistive load 2 and the first In addition, the electric potential of a metal component such as an electric wiring lead that electrically connects the second relays 3 and 4 and the resistive load 2 is solved, and the switching noise generated from the heating unit 5 at this time is The effect on the noise is stabilized, and the variation and deterioration of the conduction noise reduction performance are reduced.

  In addition, when the contact of the second relay 4 for controlling the resistance load 2 is welded, or when the contact is opened or closed up to the number of times that there is a risk of welding, the first relay 3 is surely opened. It is possible to avoid the unintended continuous energization state of the resistive load 2.

  In the present embodiment, the combination of the resistance load and the induction heating unit is shown, but it goes without saying that the same effect can be obtained even with the combination of the resistance load and the dielectric heating unit.

  As described above, the heating cooker according to the present invention stabilizes the influence of the switching noise of the induction heating type or dielectric heating type heating unit on the electrical wiring lead, and suppresses variation and deterioration of the conduction noise reduction performance. Therefore, the present invention can be applied to a combined electric cooker such as an oven microwave oven equipped with a seeder heater for roaster, an IH cooking heater equipped with a radiant heater, a sheathed heater for oven, and the like.

The circuit block diagram of the heating cooker in embodiment of this invention

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Resistive load 3 1st relay 4 2nd relay 5 Heating part 5a Switching means 5b Load coil 6 Drive circuit 7 Welding detection means 8 Contact abnormality detection means 9 Notification means 10 Counting / storage means

Claims (6)

One end of a first relay is connected to one end of a resistive load, one end of a second relay is connected to the other end of the resistive load, and the other end of the first relay and the other end of the second relay are connected to an AC power source. A series body connected to each other, an induction heating type or dielectric heating type heating unit including switching means and a load coil connected to both ends of the series body, and welding detection for detecting contact welding of the second relay And driving the heating unit and driving the first relay when the resistance load is energized to turn on the first relay, and the heating output of the resistance load is generated by the conduction / non-conduction of the second relay. with varying, said the contact welding detection time of the second relay and a driving circuit for the first relay non-conductive, wherein the drive circuit, before SL at the time of driving the heating unit, before Symbol first Drive relay to conduct Heating cooker that was by sea urchin configuration you to the state. The heating cooker as claimed in claim 1 having the informing means for informing to that effect at the time of contact welding detection of the second relay. Has contacts abnormality detection means for said drive circuit Despite outputs a drive signal first relay detects this case a non-conducting, the first at the time of detecting the non-conduction of the relay, the The cooking device according to claim 1, wherein the cooking device is configured to reduce or stop the heating output of the heating unit. The cooking device according to claim 3 having an informing means for informing to that effect at the time of non-conduction detection of said first relay. Has a count memory means for counting and storing the number of times of opening and closing of the second relay, the the count number of switching operations stored in the storage means reaches a predetermined number, stops the heating of the resistive load the heating cooker according to claim 1 or 3 to constitute the first and the second relay to a non-conducting state. 6. The cooking device according to claim 5, further comprising a notifying unit for notifying that when the number of times of opening and closing stored in the counting and storing unit reaches a predetermined number.