JP2004206939A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooker composed by restraining overall power consumption of a constituent circuit including reduction of power consumption of a noise restraining capacitor, and by enhancing reliability of constituent components for reducing power consumption. <P>SOLUTION: This heating cooker is provided with: a power switch 16 installed in an intermediate part of a power feeding path; and a serial connection body comprising a relay 12 and a capacitor 13 installed between power feeding paths on the power source side. A storage means 24 is used for storing a power phase when a control means 23 changes over the switching state of the relay 12 from a close state to an open state or vice versa; the control means 23 changes over the power phase in changing the switching state of the relay 12 to a plurality of kinds of states based on information from the storage means 24; and thus the power consumption can be restrained and the reliability of the constituent circuit components can be enhanced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating cooker that has a high-frequency noise source such as an inverter and requires a filtering circuit that leaks out of a device from a power line.
[0002]
[Prior art]
Conventionally, as this type of cooking device, for example, there is an induction cooking device as shown in FIG. 6 (see, for example, Patent Document 1). In FIG. 6, 1 is a commercial power source, 3 is a high-frequency power source that converts the commercial power source 1 into direct current to generate a high-frequency power source, 2 is a switch that connects the commercial power source 1 to the high-frequency power source 3, and 4 is induction heated by the high-frequency power source. A heating coil to be performed, 5 is a direct-current power supply that receives a commercial power supply, 6 is a control circuit that receives power supply from the direct-current power supply and outputs a signal to a power switch and a high-frequency power supply, and 7 is a capacitor for suppressing high-frequency noise. It is.
[0003]
The operation of the conventional cooking device will be described below. When the commercial power supply is supplied, the DC power supply 5 generates an output power supply of about 5 V, and the power supply is supplied to the control circuit 6. The control circuit 6 is provided with a heating on / off switch (not shown) that can be easily operated by the user. When the heating on / off switch is turned on, the switch 2 is closed and power is supplied to the high-frequency power source 3. The high-frequency power source 5 is provided with a heating drive circuit (not shown) for controlling whether or not a high-frequency current flows through the heating coil 4. After the switch 2 is closed by turning on the heating on / off switch, the control circuit 5, a high-frequency current is caused to flow through the heating coil 4 in response to the input from 5, that is, the heating operation is started.
[0004]
When the heating on / off switch is turned off during the heating operation, the high frequency current supply to the heating coil 4 is stopped by the input from the control circuit 5, that is, after the heating operation is stopped, the switch 2 is opened to supply power to the high frequency power source 3. Stop supplying.
[0005]
As described above, the power consumption of the device can be suppressed by supplying power to the high-frequency power source necessary for heating immediately before performing the heating operation and not supplying power to the high-frequency power source when heating is not performed.
[0006]
[Patent Document 1]
Japanese Patent No. 3284961 (page 3-4, Fig. 1)
[0007]
[Problems to be solved by the invention]
However, in the conventional technique, power is consumed by the DC power supply 5 and the control circuit 6, and power consumption is also present in the capacitor 7.
[0008]
It is an object of the present invention to suppress power consumption of the entire constituent circuit including reduction of power consumption of a noise suppression capacitor and to improve the reliability of a component for reducing power consumption.
[0009]
[Means for Solving the Problems]
In order to solve the above-described conventional problems, a heating cooker according to the present invention includes a power supply path for supplying power to heating means, a first switch provided in the middle of the power supply path, and the first switch. A serial connection body of a second switch and a capacitor provided between the power supply paths of the power supply side, storage means for holding information regardless of whether power is supplied, and control means for controlling opening and closing of the second switch And the storage means stores a power supply phase when the control means changes the open / close state of the second switch from open to closed or from closed to open, and the control means stores the second switch A plurality of types of power supply phases for changing the open / close state are switched based on information from the storage means.
[0010]
This reduces the power consumption of all circuits except the high-frequency noise suppression circuit with the first switch, suppresses the power consumption of the high-frequency noise suppression capacitor with the second switch, and reduces the life of the second switch due to the inrush current and arc. A cooker that can be prevented is obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 is provided between a power supply path for supplying power to the heating means, a first switch provided in the middle of the power supply path, and a power supply side power supply path of the first switch. A series connection body of a second switch and a capacitor, storage means for holding information regardless of whether power is supplied, and control means for controlling opening and closing of the second switch, wherein the storage means is the control means. Stores the phase with respect to the power supply phase when changing the open / close state of the second switch from open to closed or from closed to open, and the control means changes the open / close state of the second switch. By switching a plurality of phases with respect to the power source based on information from the storage means, power consumption is suppressed, and the power supply voltage when the second switch is opened or closed is related to whether or not power is supplied to the control means. Razz average, can be reduced, it is possible to improve the reliability of the contact welding of the switch.
[0012]
Moreover, the control means has a plurality of power supply phase timings at the time of opening / closing the second switch, and these are periodically driven each time they are opened or closed, so that the rush current and arc can be averaged to a desired level. Can be reduced. Since the previous power phase timing is sequentially stored in the non-volatile storage means, even if the power is not supplied to the control means due to the first switch off or a power failure, etc. This is continued when the second switch is driven next time.
[0013]
The invention according to claim 2 is provided between a power supply path for supplying power to the heating means, a first switch provided in the middle of the power supply path, and a power supply side power supply path of the first switch. A series connection body of a second switch and a capacitor, storage means for holding information regardless of whether power is supplied, control means for controlling opening / closing of the second switch, and open / closed state of the second switch Contact point detecting means for detecting a power phase when the voltage changes, and the storage means stores the power phase when changing the open / close state of the second switch from open to closed or from closed to open, The control means suppresses power consumption by sequentially switching the power supply phase when changing the open / close state of the second switch based on the information from the contact detection means and the storage means, and reduces the power consumption. of Time or can be reduced regardless of the closing of the power supply voltage of whether the power supply to the control means, it is possible to improve the reliability of the contact welding of the switch.
[0014]
Further, the control means sequentially compares the power supply phase when the second switch drive signal is output with the power supply phase second switch drive signal output time input from the contact detection means, and from the contact detection means when the second switch drive signal is output next time. Inrush current and arc can be reduced to a minute level by driving the input power supply phase closer to zero. Since the previous power phase timing is sequentially stored in the non-volatile storage means, even if the power is not supplied to the control means due to the first switch off or a power failure during the process, It continues even when the second switch is driven.
[0015]
In the invention described in claim 3, in particular, the second switch is opened or closed according to the energization state of the heating means, so that the noise increases or is expected to increase due to the energization of the heating means. In this case, it is possible to reduce the noise leaking to the power supply when closed, and to open the capacitor when the noise is low, thereby reducing the standby power. Moreover, the power consumption required for driving the second switch can be saved by reducing the chance of closing the second switch.
[0016]
According to the fourth aspect of the present invention, in particular, the capacitor is connected to the power line unless the first switch is opened by changing the second switch from the closed state to the open state after the first switch is opened from the closed state. Since it is connected in between, the noise reduction action by the capacitor can be obtained stably, and if the first switch is opened, the power supply is cut off and no noise is generated. By making it open, it is possible to eliminate generation of standby power by the capacitor.
[0017]
In the fifth aspect of the invention, in particular, the first and second switches are both opened by closing the second switch from open to closed after the first switch is opened to closed. Therefore, it is possible to prevent the standby power from being generated by the capacitor unless the first switch is closed.
[0018]
According to the sixth aspect of the invention, in particular, when the input terminal is disconnected from the power source when the first switch is open and the second switch is closed by connecting a discharge resistor to both ends of the capacitor. In addition, since the electric charge accumulated in the capacitor can be discharged, it is possible to prevent an electric shock by touching the input terminal.
[0019]
【Example】
Example 1
An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram of an induction heating cooker having an induction heating coil for heating a heated pan or the like with a high frequency magnetic field.
[0020]
In FIG. 1, a commercial power supply 10 is connected to an induction heating cooker via an input terminal 11 a and another input terminal 11 b, and the user can easily operate the input terminal 11 a via a common mode coil 15. The first switch is connected to the contact point of the power switch 16, the phase detection circuit 22 and the relay 20. The load-side contact of the power switch 16 is connected to a diode bridge 27 that is a full-wave rectifier circuit, a DC power source 21 composed of an insulating transformer, and a power switch open / close detection circuit 19, and the input terminal 11 b is connected via the common mode coil 15. The diode bridge 27 and the DC power supply 21 are connected, and the commercial power supply 10 is supplied to the diode bridge 27 and the DC power supply 21 via the common mode coil 15 and the power switch 16. Further, the DC power source 21 is connected to the power source on the input terminal 11a side via the contact of the relay 20 and the diode 26, and the load side contact of the relay 20 and the cathode of the diode 26 have the same polarity. The DC power source 21 is supplied with power if either the power switch 16 or the relay 20 is closed.
[0021]
Furthermore, a contact point of the relay 12, which is a second switch, and a series connection body of the capacitor 13 are connected between the input terminal 21a and the input terminal 21b. Reference numeral 14 denotes a discharge resistor connected in parallel to the capacitor. The diode bridge 27 supplies its output to the high frequency power source 17, and the high frequency power source 17 supplies a high frequency current to the heating coil 18 as heating means. The control circuit 23 which is a control means is supplied with power from the DC power source 21 and receives signals from the power switch open / close detection circuit 19 and the phase detection circuit 22, and the relay motor 12, the relay 20, the fan motor 25 for cooling the high frequency power supply 17, and the like. A signal is output to the high-frequency power source 17, and signals are input / output to / from the storage unit 24.
[0022]
The operation of the cooking device configured as described above will be described. Even if the commercial power supply 10 is connected to the input terminals 11a and 11b, the high-frequency power supply 17, the DC power supply 21, and the control circuit 23 are not supplied with power if the power switch 16 is open.
[0023]
When the power switch 16 is closed, the commercial power supply 10 is supplied to the high frequency power supply 17 and the DC power supply 21 via the diode bridge 27, and the control circuit 23 starts to operate with an output of about 5 V from the DC power supply 21. The control circuit 23 has a heating on / off switch (not shown) that can be easily operated by the user. When the heating circuit is turned on by the heating switch, the control circuit 23 also functions in the high frequency power source 17. A certain high-frequency current driving device (not shown) is turned on to cause the heating coil 18 to start supplying current, that is, heating operation. When the heating operation is started, the control circuit 23 operates the fan motor 23 to cool the high frequency power supply 17. The relay 20 supplementarily supplies the commercial power supply 10 to the DC power supply 21 by half-wave rectification, and is turned on by the control circuit 23 when a predetermined time has elapsed after the power switch 16 is closed.
[0024]
The power switch open / close detection circuit 19 detects the open / close of the power switch 16 with the waveform shown in FIG. 2- (a), and the phase detection circuit 22 detects the phase of the commercial power supply 10 with the waveform shown in FIG. 2- (b). Each output is input to the control circuit 23.
[0025]
FIG. 3 shows the drive timing of the relay. The relay 12 is closed at the timing after the power switch is closed and before the heating operation described above, and suppresses noise propagating from the high-frequency power source by a filter circuit formed by the capacitor 13 and the common mode choke coil 15. The power supply phase when the relay 12 is closed is set in advance in a plurality of stages (eight stages here) in the control circuit 23, and each time the relay is opened to closed as shown in FIG. , (5), (2), (6), (3), (7), (4), and (8) are periodically switched in this order. The storage means 24 sequentially stores the latest power supply phase timing (any one of (1) to (8) in FIG. 3) when the relay 12 is closed, and opens the power switch 16 or the relay 10. Even if the power is not supplied to the control circuit 23 due to a power failure or the like, the above-described periodic switching operation of the power phase continues. For example, even if the control circuit power supply is turned off when the power phase (6) is performed, the next relay 12 closing is performed from the timing of (3). If the storage means does not hold the phase, the control circuit is initialized, so the timing returns to (1) each time the power is turned off, and the power supply phase cannot be switched periodically.
[0026]
Next, when the power switch 16 is opened from the closed state, the power supply to the high frequency power supply 17 is stopped, and a half wave of the commercial power supply is supplied to the DC power supply 21 via the relay 20. The control circuit 23 recognizes the opening of the power switch 16 by the input from the power switch detection circuit 19, and after the power switch 16 is opened, the relay 12 is opened from the closed state, and after the relay 12 is opened, the relay 20 is opened. 13, the power supply to the discharge resistor 14 and the DC power source 21 is stopped, and the power consumption when the power switch 16 is turned off is suppressed.
[0027]
Here, the power supply phase when the relay 12 is opened from the closed state is the same as the above-described power supply phase control when the relay 12 is opened to closed (1), (5), (2), (6 ), (3), (7), (4), and (8) are periodically switched in the order, and the storage unit 24 also similarly performs the latest power supply phase timing when the relay 12 is opened (FIG. 3). (1) to (8)) are sequentially stored, and even if power is not supplied to the control circuit 23 due to the opening of the power switch 16, the opening of the relay 20, or a power failure, the power phase The periodic switching operation continues.
[0028]
As described above, according to the present embodiment, the power supply that is the first switch is provided in the middle of the power supply path (power supply path from the input terminal 11a to the diode bridge 27) that supplies the power current or voltage to the high-frequency power supply 17. Since the switch 16 is provided, and the series connection body of the relay 12 and the capacitor 13 as the second switch is connected between the power supply paths having different polarities on the power source side than the power switch 16, the power switch is opened. The heating operation by the heating coil 18 can be reliably stopped. In addition, by connecting the series connection body of the capacitor 13 and the relay 12 between the power supply paths immediately after the power switch 16 is turned on and disconnecting immediately after the power switch 16 is turned off, only when necessary at the time of driving a high frequency power supply, etc. Noise can be suppressed by a filter circuit composed of the common mode coil 15 and the capacitor 13, and the power consumption can be reduced by disconnecting the filter circuit when the power switch is turned off.
[0029]
Also, when switching the relay 12 from open to closed, regardless of whether or not power is supplied to the control circuit, the rush current and arc are averaged by periodically switching the power phase when changing the contact state. It is possible to suppress the decrease in the life of the relay that is the second switch. In this embodiment, the relay 12 is turned on in conjunction with the power switch 16 being turned on. Since the relay 12 is turned on after the normal control circuit is once initialized, the nonvolatile storage means 24 is used. Without holding the power supply phase information, the periodic switching operation of the actual power supply phase is substantially impossible, and the effect of the present invention relating to the high reliability of the relay 12 is great.
[0030]
Furthermore, when the relay 12 is opened from the closed state, similarly to the above-described open to closed state, the power supply phase at the time of changing the contact state is periodically switched regardless of whether or not power is supplied to the control circuit. Thus, the arc can be suppressed on average, and the life of the relay as the second switch can be prevented from decreasing.
[0031]
Further, by switching the relay 12 from the closed state to the open state after the power switch 16 is opened from the closed state, the capacitor 13 is connected between the power lines unless the power switch 16 is opened. If the power switch 16 is opened, the power supply is cut off so that no noise is generated. Then, the relay 12 is appropriately opened to eliminate standby power generation by the capacitor 13. be able to.
[0032]
In addition, after the power switch 16 is closed from the open state, the relay 12 is switched from the open state to the closed state. After both the power switch 16 and the relay 12 are opened, the capacitor is turned on unless the power switch 16 is closed. 13 can prevent standby power from being generated.
[0033]
Further, since the discharge resistor 14 is connected to both ends of the capacitor 13, the charge accumulated in the capacitor 13 when the input terminal is disconnected from the power source when the power switch 16 is open and the relay 12 is closed. Therefore, it is possible to prevent an electric shock by touching the input terminal.
[0034]
In the present invention, after the power switch 16 that is the first switch is changed from open to closed, the relay 12 that is the second switch is changed from open to closed, and after the power switch 16 is changed from closed to open, the relay 12 is changed. However, noise can be reduced as necessary if the operation is performed according to the energization state of the heating coil of the relay 12, that is, closed during the heating operation and opened during the heating stop. At the same time, the chance of closing the relay 12 can be reduced, and the power consumption required to drive the relay 12 can be suppressed.
[0035]
(Example 2)
FIG. 4 shows a circuit block of the second embodiment. In this figure, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof is omitted.
[0036]
4 is different from FIG. 1 only in that a contact detection means 28 for adding a signal to the control circuit 23, which is a control means, is supplied with the contact on the capacitor 13 side of the relay 12 as a second switch.
[0037]
Hereinafter, the description will be given focusing on the differences between the first embodiment and its operation. When the power switch 16 that is the first switch is closed from the open state, the control circuit 23 that is the control means thereafter switches the relay 12 that is the second switch from the open state to the closed state. The control circuit 12 calculates the drive time (referred to as t1) of the relay 12 from the power supply phase when the relay 12 is closed and the actual power supply phase when the relay 12 is closed obtained from the contact detection circuit 28. When 12 is closed, a relay close signal is output at a phase t1 before the zero point of the commercial power supply voltage. By performing the above-described operation every time the relay is closed, the actual relay drive time variation can be offset and a stable relay zero-volt closing operation can be realized. FIG. 5 graphically represents the zero volt switching operation.
[0038]
Further, the storage means 24 sequentially stores the power supply phase when the relay 12 is turned on, and even if the power is not supplied to the control circuit 23 due to the opening of the power switch 16, the opening of the relay 10 or a power failure, etc., zero volts Switching operation can be continued.
[0039]
When the power switch 16 is opened from the closed state and then the relay 12 as the second switch is opened from the closed state by the control circuit 23 as the control means, the zero volt switching operation is continuously performed in the same manner as in the closing operation of the relay 12 described above. It can be done.
[0040]
As described above, according to the present embodiment, the power supply that is the first switch is provided in the middle of the power supply path (power supply path from the input terminal 11a to the diode bridge 27) that supplies the power current or voltage to the high-frequency power supply 17. Since the switch 16 is provided, and the series connection body of the relay 12 and the capacitor 13 as the second switch is connected between the power supply paths having different polarities on the power source side than the power switch 16, the power switch is opened. The heating operation by the heating coil 18 can be reliably stopped.
[0041]
In addition, by connecting the series connection body of the capacitor 13 and the relay 12 between the power supply paths immediately after the power switch 16 is turned on and disconnecting immediately after the power switch 16 is turned off, only when necessary at the time of driving a high frequency power supply, etc. Noise can be suppressed by a filter circuit composed of the common mode coil 15 and the capacitor 13, and the power consumption can be reduced by disconnecting the filter circuit when the power switch is turned off.
[0042]
In addition, when the relay 12 is closed from the open state, the inrush current and the arc can be suppressed by continuously performing zero-volt switching regardless of whether or not the power is supplied to the control circuit. It is possible to prevent a decrease in life. In addition, a highly reliable operation that absorbs the change in time of the relay operation time (the time from when the control signal is turned on until the contact is closed or opened) is achieved.
[0043]
Furthermore, when the relay 12 is opened from the closed state, similarly to the above-described open to closed state, the arc can be suppressed by continuously performing zero-volt switching regardless of whether or not power is supplied to the control circuit. It is possible to prevent a decrease in the life of the relay that is a two-switch.
[0044]
Further, by switching the relay 12 from the closed state to the open state after the power switch 16 is opened from the closed state, the capacitor 13 is connected between the power lines unless the power switch 16 is opened. If the power switch 16 is opened, the power supply is cut off so that no noise is generated. Then, the relay 12 is appropriately opened to eliminate standby power generation by the capacitor 13. be able to.
[0045]
In addition, after the power switch 16 is closed from the open state, the relay 12 is switched from the open state to the closed state. After both the power switch 16 and the relay 12 are opened, the capacitor is turned on unless the power switch 16 is closed. 13 can prevent standby power from being generated.
[0046]
Further, since the discharge resistor 14 is connected to both ends of the capacitor 13, the charge accumulated in the capacitor 13 when the input terminal is disconnected from the power source when the power switch 16 is open and the relay 12 is closed. Therefore, it is possible to prevent an electric shock by touching the input terminal.
[0047]
In the present invention, after the power switch 16 that is the first switch is changed from open to closed, the relay 12 that is the second switch is changed from open to closed, and after the power switch 16 is changed from closed to open, the relay 12 is changed. However, noise can be reduced as necessary if the operation is performed according to the energization state of the heating coil of the relay 12, that is, closed during the heating operation and opened during the heating stop. At the same time, the chance of closing the relay 12 can be reduced, and the power consumption required to drive the relay 12 can be suppressed.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress power consumption of the entire constituent circuit including reduction of power consumption of the noise suppression capacitor and to achieve high reliability of the component parts for power consumption reduction. .
[Brief description of the drawings]
FIG. 1 is a circuit block diagram of a heating cooker in Embodiment 1 of the present invention. FIG. 2 (a) is a diagram showing input / output waveforms of a power switch open / close detection circuit in Embodiment 1 of the present invention. The figure which shows the input-output waveform of the phase detection circuit in Example 1. [FIG. 3] The figure which shows the relay drive timing in Example 1 of this invention. [FIG. 4] The circuit block diagram of the heating cooker in Example 2 of this invention. FIG. 5 is a diagram showing relay drive timing in Embodiment 2 of the present invention. FIG. 6 is a circuit block diagram of a conventional heating cooker.
10 Commercial power supply 11 Input terminal (Power supply path)
12 Relay (second switch)
13 Capacitor 14 Discharge resistor 15 Common mode choke coil (Power supply path)
16 Power switch (first switch)
18 Heating coil (heating means)
23 Control circuit (control means)
24 storage means

Claims (6)

A power supply path for supplying power to the heating means, a first switch provided in the middle of the power supply path, a second switch provided between the power supply side power supply paths of the first switch, and a capacitor in series A connection body; storage means for holding information regardless of whether power is supplied; and control means for controlling opening and closing of the second switch, wherein the storage means includes the second switch. The power phase when the open / close state is changed from open to closed or from closed to open is stored, and the control means stores the power phase when changing the open / close state of the second switch from the storage means. Cooker that switches in multiple types of phases based on the. A power supply path for supplying power to the heating means, a first switch provided in the middle of the power supply path, a second switch provided between the power supply side power supply paths of the first switch, and a capacitor in series A connection body, a storage means for holding information regardless of whether power is supplied, a control means for controlling the opening / closing of the second switch, and a power supply phase when the opening / closing state of the second switch changes Contact detecting means for performing storage, and the storage means stores a power supply phase when the control means changes the open / closed state of the second switch from open to closed or from closed to open. A heating cooker that sequentially switches the phase with respect to the power source when changing the open / close state of the second switch based on information from the contact detection means and the storage means. The cooking device according to claim 1 or 2, wherein the second switch is opened or closed in accordance with an energized state of the heating means. The heating cooker according to any one of claims 1 to 3, wherein the second switch is opened from the closed state after the first switch is opened from the closed state. The cooking device according to any one of claims 1 to 4, wherein after the first switch is changed from open to closed, the second switch is changed from open to closed. The cooking device according to any one of claims 1 to 5, wherein a discharge resistor is connected to both ends of the capacitor.

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