JP2894114B2 - Induction heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating cooker having a communication function.

[0002]

2. Description of the Related Art In recent years, induction heating cookers have been recognized for their excellent features of safety, cleanliness, and high efficiency, and have been widely used in ordinary households. The induction heating cooker has a structure in which a load pan magnetically coupled with the heating coil is induction-heated by applying a high-frequency current of several tens KHz to a heating coil spread in a spiral planar shape. The high-frequency current is generated by opening and closing the switching means in the induction heating unit.

A conventional induction heating cooker will be described below. FIG. 14 is a circuit diagram of a conventional induction heating cooker. In FIG. 14, 1 is an AC power supply, 2 is a power switch, 4 is an induction heating unit, and a rectifier 40, a heating coil 4
1, a switching means 42 and an inverter circuit 43. When the switching means 42 is turned on, a current having a constant gradient flows through the heating coil 41. The gradient of this current is proportional to the voltage value of the AC power supply 1 and inversely proportional to the inductance of the heating coil 41.

In the control unit 5, the induction heating unit control means 50 controls the opening and closing of the switching means 42 and controls the conduction time of the switching means 42 to control the current applied to the heating coil 41. In addition, the inverter circuit 43
Is detected, and when the induction heating section 4 is in an abnormal state, measures such as stopping the heating are taken.

[0005] In the operation unit 6, various settings such as a cooking mode and a setting output are changed and maintained by the mode control means 60, and a user of the device inputs the change of the setting by the input means 70, and the display means 71. The setting is displayed with.

The control unit 5 and the operation unit 6 include modulation means 51 and 61 and demodulation means 52 and 62, respectively.
The modulating means 51 and 61 convert the input signal from the induction heating section control means 50 or the mode control means 60 into a digital signal and transmit the digital signal.
2 and receive and restore.

Next, the operation will be described. The user of the device inputs the predetermined cooking mode / output setting into the input means 70
In response to this input, the mode control means 60 changes the output setting of the cooking mode / induction heating unit 4,
The user is notified of the changed settings through the display means 71. Then, the setting is converted into a digital signal by the modulation means 61 and transmitted to the demodulation means 52 of the control unit 5.

In the control unit 5, the demodulation unit 52 receiving this signal restores the digital signal to the original setting, and the induction heating unit control unit 50 controls the switching unit 42 based on this setting.

When an abnormality of the induction heating unit 4 is detected by the induction heating unit control unit 50, the modulation unit 51 of the control unit 5
Mode control means 60 through demodulation means 62 of operation unit 6
To the abnormality of the induction heating unit 4.

[0010]

However, in the above conventional configuration, the heating coil 41 and the inverter circuit 43 are not provided.
High frequency noise caused by the high frequency current flowing through the control unit 5 and the operation unit 6 is generated. Since the high-frequency noise increases as the voltage of the AC power supply 1 increases, the high-frequency noise is susceptible to the noise depending on the timing of signal transmission and reception and the propagation speed of the signal. There is a problem of inviting.

An object of the present invention is to solve the above-mentioned conventional problems, and it is a first object of the present invention to improve the reliability of communication by making it less susceptible to noise generated by an induction heating unit.

[0012] It is another object of the present invention to make it possible to judge the suitability of a received signal with a simple configuration and to easily perform a process at the time of reception failure, and to easily and promptly judge an abnormality on the transmission side. This is the purpose of 2.

Further, the communication abnormality is accurately determined, the output of the induction heating unit is stopped, the setting change to the unsafe operation mode is prohibited,
A third object is to perform communication abnormality processing such as display of communication abnormality.

It is a fourth object of the present invention to accurately discriminate a zero voltage detection abnormality on the communication partner side and to prevent the induction heating section from being placed in an unsafe operation state due to the zero voltage abnormality.

Further, the disconnection of the communication line is accurately determined,
A fifth object is to prevent the induction heating unit from being put into an unsafe operation state due to communication failure when the communication line is disconnected.

[0016]

In order to achieve the first object, an induction heating cooker according to the present invention comprises a zero voltage detecting means for detecting a zero voltage of an AC power supply, wherein the control unit and the operating unit are provided. Encodes the output signal of the induction heating section control means or the mode control means into a digital signal of a predetermined number of digits, and reaches the next zero voltage point after passing the zero voltage point based on the output of the zero voltage detection means. Modulating means for outputting one digit of the digital signal and holding the output content at least until near the next zero voltage point;
A signal is input near the zero voltage point based on the output of the zero voltage detection means, and a demodulation means for restoring a coded signal after inputting the signal to a predetermined number of digits is provided. The first means for solving the problem is configured to perform communication with the section.

In order to achieve the second object, the control section and the operation section each include modulation control means, and the modulation control means controls the modulation means so as to periodically transmit a signal at a predetermined cycle. And holds the latest input signal from the induction heating unit control means or the mode control means, and the latest input signal immediately before the start of signal transmission in the predetermined cycle or before the predetermined time. The output to the modulating means is defined as a second problem solving means.

Further, in order to achieve a third object, the control unit and the operation unit determine whether part or all of a received signal matches part or all of a signal transmitted immediately before receiving the signal. A control unit for controlling the modulation unit of the control unit to start modulation and transmission immediately after the determination unit of the control unit determines a signal or after a predetermined time period. The operation unit performs signal transmission periodically at a predetermined cycle and waits for transmission from the completion of one signal transmission to the start of the next signal transmission by the signal of the modulation unit of the operation unit. An operation unit modulation control unit that controls the modulation unit of the operation unit so as to be equal to or longer than a time until the modulation unit of the control unit completes the signal transmission after the completion of the transmission, and includes a determination result of the determination unit. Flip what was configured to perform communication abnormality processing by the induction heating part controlling means or said mode control means is a third means for solving problems.

Further, in order to achieve a fourth object, the control unit and the operation unit are provided with a zero voltage abnormality determining means for determining an abnormality of the zero voltage detecting means, and the zero voltage on the communication partner side based on an input signal. The communication partner abnormality detecting means for detecting abnormality of the voltage detecting means is provided, and the modulation means fixes an output to a predetermined logic in accordance with an input from the zero voltage abnormality determining means, and outputs the output of the communication partner abnormality detecting means. According to a fourth aspect of the present invention, a communication partner abnormality process is performed by the induction heating unit control means or the mode control means accordingly.

Further, in order to achieve a fifth object, the control section and the operation section each include a communication disconnection detecting means for detecting a disconnection of a communication line connecting the modulation means and the demodulation means. A fifth aspect of the present invention is a fifth aspect of the present invention, in which the communication line disconnection processing is performed by the induction heating section control means or the mode control means according to the output of the means.

[0021]

According to the first means for solving the above problems, the modulating means outputs one digit of a coded digital signal after passing the zero voltage point of the AC power supply and before reaching the next zero voltage point,
Since the output content is held at least until the vicinity of the next zero voltage point, a signal can be reliably transmitted one digit at a time for a predetermined time before and after the zero voltage point where the high frequency noise from the induction heating unit is least generated. . Further, the demodulation means inputs a one-digit signal near the zero voltage point of the AC power supply and demodulates the coded digital signal after completing the input of the signal up to a predetermined number of digits, so that the output signal of the modulation means is induced. Signals can be received one digit at a time in the vicinity of zero voltage where the generation of high-frequency noise from the heating unit is least and within the transmission period, and the reliability of communication can be improved.

Further, according to the second problem solving means, a modulation control means for controlling the modulation means to periodically transmit a signal at a predetermined cycle is provided. It is possible to receive again after a predetermined time without replying to the communication side, and it is not necessary to take countermeasures against communication errors such as returning information on the success or failure of reception to the communication side, and the configuration of the modulation means and demodulation means is simple. Can be Further, by performing the communication periodically, it is possible to determine that some abnormality has occurred on the transmitting side when the signal is not periodically received by the demodulation means.

Furthermore, the third problem solving means determines whether or not the transmitted information coincides with a part or all of the information received from the communication partner immediately after that, so that the information is correctly transmitted to the partner and Can be confirmed to be correctly obtained, and an abnormality that cannot be detected by exclusive OR determination or the like which is a comparison determination with inverted data can also be detected. Then, according to the determination result of the determination unit, the output of the induction heating unit is stopped, the setting change to the unsafe operation mode is prohibited, the communication abnormality processing such as the display of the communication abnormality is performed, and the unsafe operation due to the communication abnormality is performed. It is possible to notify the user of the avoidance or the communication abnormal state to the user, and it is possible to ensure the safety when the communication abnormality occurs.

Further, according to the fourth problem solving means, the modulating means fixes the output to a predetermined logic in accordance with the output of the zero voltage abnormality determining means for determining the abnormality of the zero voltage detecting means, and communicates based on this output. Since the partner abnormality detecting means detects the abnormality of the communication partner side and the induction heating section control means or the mode control means performs the abnormality processing, the power failure of the AC power supply or the failure of the zero voltage detecting means and further the zero voltage detecting means and other If the zero voltage abnormality such as the disconnection of the signal from the zero voltage detection means due to the disconnection of the cable line connecting the means, the output of the induction heating unit is stopped, the setting change to the unsafe operation mode is prohibited, and the zero voltage abnormality is detected. It is possible to perform display and the like, and when the output signal of the zero voltage detecting means as described above is abnormal, it is possible to ensure safety and easily confirm that the cause of the equipment failure is the zero voltage abnormality. Can Unisuru.

Further, according to the fifth problem solving means, when the communication line is disconnected, the output of the induction heating unit is stopped, the setting change to the unsafe operation mode is prohibited, and the display indicating that the communication line is disconnected is provided. To secure the safety at the time of the disconnection of the communication line, and to easily confirm that the cause of the failure of the device is the disconnection of the communication line.

[0026]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. In this embodiment, the same components as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. The characteristic configuration of this embodiment is as follows.
A zero voltage detecting means 3 for detecting a zero voltage of the AC power supply 1 is provided, and a demodulating means 54 for receiving signals one digit at a time near the zero voltage point detected by the zero voltage detecting means 3 is provided to the control unit 5 and the operation unit 6. And 64, similarly, based on the output signal of the zero voltage detection means 3, starts signal output after a predetermined time has elapsed from the zero voltage point and before reaching the next zero voltage point, and outputs a signal near the next zero voltage point. Modulating means 53 and 63 for holding output contents for a predetermined time until the lapse of time are provided. That is, the zero voltage detecting means 3 generates a pulse waveform which becomes “H” when the instantaneous voltage of the AC power supply 1 is equal to or lower than a predetermined value (sufficiently smaller than the peak value), and the demodulating means 54 and 64 detect the zero voltage. 1 when the output of the means 3 is "H"
The signal is received digit by digit, and the modulating means 53 and 63 change the signal transmission output before the reception timing, and hold the output only for the receivable time.

The operation of the induction heating cooker configured as described above will be described with reference to FIGS. 2 and 3.
FIG. 2 is a diagram showing the contents of the transmission signals of the modulation means 53 and 63. The contents of the cooking mode and the output setting input from the input means 70 are encoded into a 5-bit digital signal by the modulation means 63 of the operation unit 6 as shown in FIG. Data, start bit and stop bit are added. In the present embodiment, a 5-bit digital signal in which the cooking mode and output setting are coded earlier as 1 bit for “0” for the start bit, 1 bit for the stop bit, and cooking mode and data as communication error detection data is inverted. Add.

Further, the induction heating section control means 50 detects abnormalities in the inverter circuit 43, abnormal high temperatures in the switching means 42,
Alternatively, when an abnormality of the induction heating unit 4 is detected, such as indirect detection of an abnormal temperature of an object to be cooked using a temperature-sensitive element, a signal corresponding to the abnormality is output, and the modulation unit of the control unit 5 as shown in FIG. At 53, the signal is encoded into a 3-bit digital signal, and a start bit, a stop bit, and communication error detection data are added as described above.

FIG. 3 is a diagram showing the transmission timing of the modulation means 53 and 63. As shown in FIG. 3, assuming that the period of the two pulse waveforms of the zero voltage detecting means 3 is T1, the modulating means 53 and 63 detect the rising edge of the pulse waveform after a lapse of time T1 / 2, that is, between the two pulse waveforms. Is output one bit at a time at the center of
This output level is held until the time T1 / 2 elapses after the next rise is detected. As a result, there is no interval between one output and the next output, and the modulating means 53 and 63 do not need to count the two times of the output start timing and the output holding time. Since it is sufficient to count only 2, the modulation means 5
3 and 63 are simplified. Note that the modulating means 53
And the relationship between the 1-bit data and the output level is that when the data is “0”, “L” is output, and when the data is “1”, “H” is output.

FIG. 4 is a diagram showing the reception timing of the demodulation means 54 and 64. Modulation means 53 and 63
When the pulse waveform width of the zero-voltage detecting means 3 is T2 in the demodulating means 64 and 54 as shown in FIG. 4 after the time T2 / 2 has elapsed since the rising edge of the pulse waveform was detected, as shown in FIG. That is, it receives one bit at a time at the center of one pulse waveform. The standby time T2 / 2 is set so that the noise due to the induction heating unit 4 is minimized. However, if T2 is sufficiently smaller than the pulse interval T1, the standby time is eliminated and the pulse waveform is reduced. Even if the demodulation means 54 and 64 receive the signal immediately after the rising edge detection, the time counting operation for determining the reception timing is eliminated while the high-frequency noise hardly affects the received signal, and the configuration of the demodulation means 54 and 64 is simplified. can do.

The demodulation means 54 and 64 take measures such as matching the received data a plurality of times and determining the majority of the input data a plurality of times to determine whether the received 1-bit data is "0" or "1".
If the received data is a start bit, the data is held for a predetermined bit length from the next bit to the stop bit detection. After the detection of the stop bit or the reception of the data having the predetermined bit length, the received signal is separated into a normal signal component and an inverted component, and the exclusive OR of both is performed. If there is no problem in the communication, as a result of the exclusive OR, all bits become "1". In this case, the digital signal received by the demodulation means 54 in the control unit 5 is demodulated into the cooking mode and the setting output signal. The signal is output to the induction heating section control means 50, and the demodulation means 64 demodulates into an abnormal mode signal of the induction heating section 4 by the operation section 6 and outputs the signal to the mode control means 60.

However, in the case where one of the corresponding bits of the normal signal component and the inverted component has been successfully received but the other one has failed, the exclusive OR operation is performed, and the bit becomes "0". By detecting this, a communication error is detected and the current information is discarded. In this way, countermeasures are taken to prevent an erroneous cooking mode / output setting signal or abnormal mode signal due to a communication error from being output to the induction heating section control means 50 and the mode control means 60.

In addition, a process for retransmitting when reception fails as described above is also conceivable. In this case, after detecting a communication error, a retransmission request signal is transmitted from the modulating means 53 or 63, and upon receiving this signal, the mode control means 60 or the induction heating section control means 50 modulates the modulating means 53 or 63.
To perform signal transmission again. If the reception is successful, a reception success signal is transmitted from the modulation means 53 or 63, and upon receiving this signal, the mode control means 60 or the induction heating section control means 50 enters a state in which a new signal can be transmitted. Note that the retransmission request signal and the reception success signal are hereinafter collectively referred to as a communication success / failure signal.

Further, the latest cooking mode / setting output signal received in the past when the abnormal mode signal of the induction heating section 4 is transmitted by the induction heating section control means 50 is transmitted to the cooking mode / setting output signal by the mode control means 60. In addition, the latest abnormal mode signal received in the past at the time of transmission is output together, and the modulation means 53 and 63 encode and transmit the signal including both communication elements of FIGS. 2A and 2B, If the information restored in the demodulation units 54 and 64 is selected by the induction heating unit control unit 50 or the mode control unit 60, the modulation units 53 and 63 and the demodulation units 54 and 64 are the same. It can be configured.

With the above configuration, the demodulation means inputs 1-bit data near the zero voltage point of the AC power supply, and the modulation means outputs a digital signal one bit at a time before the zero voltage point to output the digital signal. By maintaining the output level until near the voltage point, data is transmitted and received one bit at a time when the zero voltage point, which is the least affected by noise, arrives, and the effect of high frequency noise generated by the induction heating unit is reduced. It is possible to improve the reliability of communication by making it hard to receive.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is that the control unit 5 and the operation unit 6 control the modulation unit 53 or 63 so that signal transmission is performed periodically at a predetermined cycle, and the induction heating unit control unit 50 or the mode. A modulation control means 55 for holding the latest input signal from the control means 60 and outputting the latest input signal to the modulation means 53 or 63 immediately before the start of signal transmission in the predetermined cycle or before the predetermined time; 65 are added.

In the first embodiment, when the control unit 5 detects a communication error in the demodulation unit 54, the control unit 5 transmits a retransmission request signal from the modulation unit 53 and requests the operation unit 6 to transmit again. Signal transmission is attempted again. However, in this case, the modulation means 53 cannot simultaneously transmit the communication success / failure signal including the retransmission request signal and the original signal. Signal transmission switching control must be performed. Further, even if the modulating means 63 transmits a signal, it is not known when the demodulating means 64 receives the communication success / failure signal, and the modulation means 63 cannot transmit a new signal until the communication success / failure signal is received. As the frequency of transmission increases, communication efficiency deteriorates.

This embodiment improves this point.
The operation of the induction heating cooker configured as described above will be described with reference to FIG. FIG. 6 is a diagram for explaining the operation of the modulation control means 65. In the operation unit 6, the modulation control unit 65 holds the latest various setting signals output from the mode control unit 60 and outputs the signals to the modulation unit 63. Further, the modulation control means 65 outputs the pulse waveform of the zero voltage detection means 3 to the modulation means 63 as a transmission control pulse. Upon receiving these, the modulation means 63 encodes various setting signals into digital signals, and when a transmission control pulse is input from the modulation control means 65, the data is transmitted one bit at a time.

When the modulation control means 65 outputs a transmission control pulse by a predetermined number of bits and completes the transmission of the modulation means 63, the supply of the transmission control pulse is stopped for a predetermined time. Then, the modulating means 63 keeps outputting “H”. After a predetermined time has elapsed, various setting signals of the mode control means 60 and transmission control pulses are output to the modulation means 63, and the modulation means 63 starts transmitting digital signals again. As described above, the modulating means 63 repeats signal transmission and transmission standby periodically at a predetermined cycle.

Here, the reason why the modulation control means 65 stops supplying the transmission control pulse for a predetermined time will be described.
The supply suspension period can be omitted, but the time required for the demodulation means 54 of the control unit 5 to perform a communication error detection operation, demodulation, output to the induction heating unit control means 50, etc. after receiving data of a predetermined bit length. Is to ensure. In addition, by fixing the output of the modulating means 63 to "H" during this time, there is an effect that the demodulating means 54 can surely detect the next start bit "L".

Next, the control unit 5 for receiving the digital signal will be described. When the demodulation unit 54 of the control unit 5 receives data of a predetermined bit length and detects a communication error by exclusive OR processing, the current reception signal is discarded and the reception of the next digital signal is waited. In this case, nothing is output to the induction heating section control means 50 and the induction heating section control means 5
There is no change in the state of 0. However, after a predetermined time, the digital signal can be received again. If there is no abnormality in the received signal, the digital signal is demodulated and output to the induction heating section control means 50.

Similarly, the modulation control means 55 of the control unit 5
As a result, the demodulation unit 64 of the operation unit 6 can periodically receive a signal from the modulation unit 53 of the control unit 5 at a predetermined cycle.

Further, since the signals are transmitted periodically in the modulating means 53 and 63, the demodulating means 54 and 64 can receive the signals periodically. Therefore, when the signal is not received by the demodulation means 54 and 64 for a predetermined time or more, it can be determined that normal transmission cannot be performed due to some abnormality on the transmission side.

With the above-described configuration, it is possible to receive a retransmission request again after a predetermined period of time without returning a retransmission request to the other party in the case of a reception failure. Therefore, it is possible to omit a complicated process at the time of a communication error and to provide a simple configuration in which the modulation means and the demodulation means only communicate an abnormal signal of the induction heating section control means or various setting signals of the mode control means. In addition, by performing regular communication, when a signal is not received regularly by the demodulation means, it can be determined that some abnormality has occurred.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is that the control unit 5 and the operation unit 6 determine whether or not part or all of the received signal coincides with part or all of the signal transmitted immediately before receiving the signal. And 66 are added, and the control unit 5 controls the modulation unit 53 to start the modulation / transmission immediately after the determination of the received signal or after a predetermined time based on the output signal of the determination unit 56 of the control unit 5. A modulation control unit 57 is added to the operation unit 6 to control the modulation unit 63 of the operation unit so that signal transmission is periodically performed at a predetermined cycle, and the transmission standby time shown in FIG. The operation unit modulation control means 67, which is set to a time equal to or longer than the time from the completion of transmission of the signal 63 to the completion of transmission of the modulation means 53 of the control unit 5, is added. control Stop of the output of the induction heating unit 4 by the step 50 or change of the setting to the unsafe operation mode by the mode control means 60 (change from the low output setting to the high output setting, change from the heating stop to the heating state, etc.) prohibition, communication That is, communication abnormality processing such as displaying an abnormal state is performed.

In the exclusive OR process used as the communication error detection method in the first embodiment, if there is a reception error in the same part of the normal signal component and the inverted component, the communication error cannot be detected.

The present embodiment improves this point.
The operation of the induction cooking device configured as described above will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram showing the contents of a communication signal in the third embodiment. First, the determination means 56 or 66 compares the signal demodulated by the demodulation means 54 or 64 with the signal output from the control section modulation control section 57 or the operation section modulation control section 67. Therefore, the transmitted and received signal contents are unified in the control unit 5 and the operation unit 6 as partially described in the first embodiment, and the signal contents modulated and transmitted by the modulation units 53 and 63 are transmitted to the demodulation unit 54 and 64, which is included in the signal content demodulated. That is, as shown in FIG. 8, all the communication elements of the control unit 5 and the operation unit 6 have a combined signal content. Then, the abnormal mode component of this signal can be changed only by the induction heating unit control means 50, and the cooking mode,
The output component can be changed only by the mode control means 60.

Further, in order to determine the coincidence between the transmission signal and the reception signal, it is necessary to clarify the reception timing of the reception signal corresponding to the transmitted signal. For this purpose, the control unit modulation control unit 57 is configured to output a signal to the modulation unit 53 based on the determination result of the received signal by the determination unit 56 of the control unit 5 to start the modulation / transmission operation. Numeral 67 designates a transmission standby time for prohibiting the signal transmission of the modulation means 63 to be equal to or longer than the time from the completion of the signal transmission by the modulation means 63 of the operation unit 6 to the completion of the signal transmission by the modulation means 53 of the control unit 5. Thereby, the modulating means 6 of the operation unit 6
3 and demodulation means 54 of the control unit 5, modulation means 53 of the control unit 5
And the transmitting / receiving operation of the demodulating means 64 of the operation unit 6 can be alternately performed. The signal output from the control unit modulation control unit 57 or the operation unit modulation control unit 67 can be specified so as to be transmitted by the modulation unit 53 or 63 immediately before. Further, since the operation unit modulation control unit 57 periodically transmits a signal, it is possible to prevent a state in which communication is disabled due to reception waiting of both the demodulation unit 54 of the control unit 5 and the demodulation unit 64 of the operation unit 6.

Next, a method of determining the coincidence between the transmission signal and the reception signal will be described. FIG. 9 is a diagram for explaining the determination method of the determination means 56 and 66. First, the determination unit 66 of the operation unit 6 inputs a cooking mode and setting output signal to be transmitted when the modulation unit 63 of the operation unit 6 starts transmission from the operation unit modulation control unit 67. As shown in FIG. 9A, the setting for transmission is the heating mode (01B), and the output is “7”.
In the case of (111B), the data of 01111B is
Is input to the determination means 66. The heating mode indicates a state in which a high-frequency current is applied to the heating coil 41.

Then, a signal is transmitted from the modulating means 63 to the demodulating means 54 of the control section 5, and a signal is transmitted from the modulating means 53 after judging the coincidence through the judging means 56. This signal is received and demodulated by the demodulation unit 64 of the operation unit 6 and then output to the determination unit 66. Then, the judging means 66 extracts the cooking mode / setting output component from the signal input from the demodulating means 64. As shown in FIG. 9A, if the signal of this part is 01011B, this signal means the heating mode (01B) and the output “3” (011B), and the setting different from the transmitted setting is received. It will be done. When such a communication abnormality is detected, the judgment means 66
Is to discard all signal components received this time and
Do not transmit to 0.

When the communication abnormal state as described above is detected ten times in succession, the judging means 66 informs the mode control means 60 to perform the communication abnormal processing, and the mode control means 60 turns off the output of the induction heating unit 4. , And the reception of a signal from the input means 70 that shifts to an unsafe mode such as a heating mode is prohibited. The display means 71
Indicates that the communication is in an abnormal state, and alerts the user.

If the above-described communication abnormality processing is performed immediately after a single abnormality has occurred, even a small amount of noise is often determined to be a communication abnormality, and the device does not operate normally. For this reason, the communication abnormality process is performed only when the communication is completely impossible due to relatively large noise such that the communication abnormality state continues ten times.

The same applies to the control unit 5, for example, as shown in FIG.
The data of the abnormal mode transmitted as shown in FIG.
If the received data is different from 011B with respect to 1B, it is determined that the communication is abnormal, and all the received signal components this time are not transmitted to the induction heating unit control means 50. When such a communication abnormality is detected ten times in succession, the output of the induction heating unit 4 is stopped by the induction heating unit control means 50.

According to the above-described configuration, the transmission setting and the reception setting are determined to coincide with each other, and when an abnormal result of the coincidence determination is continuously detected a predetermined number of times, the output of the induction heating unit is stopped and the setting change to the unsafe operation mode is prohibited. By performing a communication error process such as displaying a communication error, it is possible to avoid an unsafe operation due to the communication error or to display to the user that the communication is abnormal.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIG. The difference from the second embodiment is that the control unit 5 and the operation unit 6 are provided with zero voltage abnormality determining means 58 and 68 for determining abnormality of the zero voltage detecting means 3 and zero voltage on the communication partner side based on an input signal. Modulation means 59 and 69 add the communication partner abnormality detection means 5a and 6a, respectively, for detecting abnormality of the detection means 3, and fix the output to "L" according to the input from the zero voltage abnormality determination means 58 or 68. In this way, when an abnormality is detected by the communication partner abnormality detecting means 5a or 6a, the output of the induction heating section 4 is stopped by the induction heating section control means 50 or the setting change to the unsafe operation mode is prohibited by the mode control means 60, and the zero voltage is detected. That is, an indication that the output of the means 3 is in an abnormal state or the like is made.

The operation of the induction cooking device configured as described above will be described with reference to FIG. FIG. 11 is a diagram for explaining a method of detecting a zero voltage abnormality of a communication partner. First, consider the case where the operation unit 6 has a zero voltage abnormality. The zero voltage abnormality determining means 68 determines that the pulse waveform from the zero voltage detecting means 3 rises abnormally after waiting for a predetermined time, and outputs it to the modulating means 69. While receiving this signal, the modulating means 69 fixes the output to "L". Then, the communication partner abnormality detecting means 5 a of the control unit 5 receives data during the pulse waveform “H” of the zero voltage detecting means 3.

If this state continues after the abnormality determination by the zero voltage abnormality determination means 68, the communication partner abnormality detection means 5
“a” continuously receives “L” data. And 10
When "L" is continuously received 0 times, it is determined that the operation unit 6 has lost communication due to the zero voltage abnormal state, and the induction heating unit control means 50 stops the output of the induction heating unit 4. To control. In order to determine the number of consecutive times, it is necessary to perform communication periodically at a predetermined cycle, and the number of times needs to be set to a number at which the reception signal “L” cannot occur continuously in normal communication. Also, since the communication error is detected by the exclusive OR process in the demodulation means 54 from the time when the operation unit 6 determines the zero voltage abnormality to the time when the control unit 5 performs the communication partner abnormality processing, the induction heating unit control means 50 Continues the previous mode.

Similarly, when the communication partner abnormality detecting means 6a of the operation unit 6 detects the zero voltage abnormal state of the control unit 5,
The mode control means 60 prohibits the reception of signals from the input means 70 for shifting to an unsafe operation mode such as a heating mode, and the display means 71 displays an indication that communication is impossible due to a zero voltage abnormality. Do.

With the above-described configuration, the induction heating is detected by detecting a power failure of the AC power source on the communication partner side, a failure of the zero voltage detecting means, and a zero voltage abnormality due to the disconnection of the signal from the zero voltage detecting means due to the disconnection of the cable. Processing such as stopping the output of the unit, prohibiting the setting change to the unsafe operation mode, and displaying that the communication partner is in a zero voltage abnormal state can be performed.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to FIG. The difference from the second embodiment is that the control unit 5 and the operation unit 6 are configured such that the input is fixed to “H” when the communication line is disconnected, and the reception signal “H” is continuously received 100 times. Communication disconnection detecting means 5b and 6b for detecting disconnection of communication line are added respectively. When disconnection of communication line is detected, output of induction heating unit is stopped, setting change to unsafe operation mode is prohibited, and communication line disconnection state is established. Is displayed.

The operation of the induction cooking device configured as described above will be described with reference to FIG. FIG. 13 is a diagram for explaining a method of detecting a communication line disconnection. The input of the communication disconnection detecting means 5b is usually equal to the output of the modulating means 69 of the operation unit 6. However, if the communication line is disconnected, the input of the communication disconnection detecting means 5b becomes undefined. And the control unit 5
The communication disconnection detecting means 5b receives data during the pulse waveform "H" of the zero voltage detecting means 3.

As shown in FIG. 13, if the communication line disconnection state continues, the communication disconnection detecting means 5b continuously receives "H" data. When "H" is received 100 times continuously, it is determined that communication has been disabled due to the disconnection of the communication line, and the induction heating unit control means 50 controls the output of the induction heating unit 4 to be stopped. I do. In order to determine the number of consecutive times, it is necessary to perform communication periodically at a predetermined cycle, and it is necessary to set the number of times to a number at which the reception signal “H” cannot occur continuously in normal communication. Also,
During the period from when the communication line is disconnected to when the control unit 5 performs the communication line disconnection process, the demodulation unit 54 of the control unit 5 detects a communication error by the exclusive OR process.
Continues the previous mode.

Similarly, when the communication disconnection from the control unit 5 is detected by the communication disconnection detection unit 6 b of the operation unit 6, the cooking mode is set by the mode control unit 60, meaning that the output of the induction heating unit 4 is stopped. The reception of a signal from the input unit 70 that shifts to the unsafe operation mode such as the heating mode in the initial mode is prohibited, and the display unit 71 displays that communication is impossible due to the disconnection of the communication line.

Further, the fixed logic of the communication disconnection detecting means 5b and 6b at the time of the communication disconnection is made opposite to the output logic of the modulation means 59 or 69 at the time of the abnormal zero voltage state described in the fourth embodiment. , Both the zero voltage abnormality and the communication line disconnection abnormality can be detected and distinguished.

With the above-described configuration, the disconnection of the communication line is detected, and the output of the induction heating unit is stopped, the setting change to the unsafe operation mode is prohibited, and the communication line disconnection state is displayed. By performing the processing, it is possible to eliminate an unsafe operation due to communication failure when the communication line is disconnected.

The zero voltage detecting means 3 and the zero voltage abnormality judging means 58 and 68 can also be used if they have similar functions in the conventional configuration. Also,
It is clear that a part or all of the control unit 5 and all or a part of the operation unit 6 can be performed by a microcomputer.

[0068]

As described above, the induction heating cooker according to the present invention is provided with the zero voltage detecting means for detecting the zero voltage of the AC power supply, and the control unit and the operation unit are controlled by the induction heating unit control means or the mode. The output signal of the control means is coded into a digital signal of a predetermined number of digits, and one digit of the digital signal is passed through the zero voltage point until reaching the next zero voltage point based on the output of the zero voltage detection means. A modulating means for outputting and holding the output content at least until the time near the next zero voltage point elapses, a signal is input near the zero voltage point based on the output of the zero voltage detecting means, and the signal is output up to a predetermined number of digits. A demodulation means for restoring a coded signal after input is provided, so that data can be transmitted and received one bit at a time at a zero voltage point which is least susceptible to high frequency noise. And insensitive to noise can be improved communication reliability.

As a second means, the control section and the operation section control the modulation means so as to periodically transmit a signal at a predetermined cycle, and receive a signal from the induction heating section control means or the mode control means. Modulation control means for holding the latest input signal and outputting the latest input signal to the modulation means immediately before the start of signal transmission in the predetermined cycle or before the predetermined time, respectively, is provided with a simple configuration. It is possible to judge whether the received signal is appropriate or not, and to easily perform the process when the reception fails, and it is possible to determine that the transmission side is abnormal by not receiving the signal periodically.

Further, as a third means, the control section and the operation section each have a judgment means for judging the coincidence of a part or all of the received signal with a part or all of the signal transmitted immediately before the signal reception. The control unit includes a control unit modulation control unit that controls the modulation unit of the control unit to start modulation and transmission immediately after the determination unit of the control unit determines the signal or after a predetermined time, The operation unit periodically performs signal transmission at a predetermined cycle and waits for transmission from the completion of one signal transmission to the start of the next signal transmission after the completion of signal transmission by the modulation unit of the operation unit. An operation section modulation control section for controlling the modulation section of the operation section so as to be equal to or longer than a time required for the modulation section of the control section to complete the signal transmission; With the structure for performing the communication abnormality processing by the heating part controlling means or said mode control means, output stop of the induction heating unit for communications error to determine accurately,
It is possible to ensure the safety in the event of a communication error by performing a communication error such as prohibiting setting change to the unsafe operation mode and displaying a communication error.

Further, as a fourth means, the control section and the operation section are provided with a zero voltage abnormality determining means for determining an abnormality of the zero voltage detecting means, and an abnormality of the zero voltage detecting means on the communication partner side based on an input signal. The modulation means fixes the output to a predetermined logic according to the input from the zero voltage abnormality determination means, and the induction heating according to the output of the communication partner abnormality detection means. With the configuration in which the communication partner abnormality processing is performed by the unit control means or the mode control means, it is possible to avoid an unsafe operation due to an abnormality in the output signal of the zero voltage detection means or to perform display to a person who uses the device. .

Further, as a fifth means, the control section and the operation section each include a communication disconnection detecting means for detecting a disconnection of a communication line connecting the modulating means and the demodulating means, and respond to an output of the communication disconnection detecting means. By performing a communication partner abnormality process by the induction heating unit control means or the mode control means, it is possible to avoid unsafe operation due to communication failure when a communication line is disconnected or to display to a user of the device. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of an induction heating cooker according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining transmission signal contents of a modulation unit of an operation unit and a control unit;

FIG. 3 is a transmission timing chart of a modulation unit.

FIG. 4 is a reception timing chart of a demodulation unit.

FIG. 5 is a block diagram of an induction heating cooker according to a second embodiment of the present invention.

FIG. 6 is an operation timing chart of a modulation control unit.

FIG. 7 is a block diagram of an induction heating cooker according to a third embodiment of the present invention.

FIG. 8 is a diagram for explaining unified signal contents in a control unit and an operation unit;

FIG. 9 is a diagram illustrating a determination method of a determination unit of an operation unit and a control unit.

FIG. 10 is a block diagram of an induction heating cooker according to a fourth embodiment of the present invention.

FIG. 11 is a diagram illustrating a method of detecting a zero voltage abnormality of a communication partner.

FIG. 12 is a block diagram of an induction heating cooker according to a fifth embodiment of the present invention.

FIG. 13 is a diagram illustrating a method for detecting a disconnection of a communication line.

FIG. 14 is a block diagram of an induction heating cooker in a conventional example.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 2 Power switch 3 Zero voltage detection means 4 Induction heating unit 5 Control unit 6 Operation unit 40 Rectifier 41 Heating coil 42 Switching means 43 Inverter circuit 50 Induction heating unit control means 53 Modulation means 54 Demodulation means 60 Mode control means 63 Modulation Means 64 Demodulation means 70 Input means 71 Display means

Continuation of the front page (72) Inventor Yuji Fujii 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-152338 (JP, A) JP-A-2-12790 (JP) JP-A-60-239145 (JP, A) JP-A-4-12642 (JP, A) JP-A-3-2511058 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB (Name) H05B 6/12

Claims (5)

(57) [Claims] An induction heating section including a heating coil and switching means, a control section including induction heating section control means for controlling the induction heating section, and input means and various settings such as a cooking mode and output setting are controlled. An operation unit including mode control means;
The control unit and the operation unit include a zero voltage detection unit for detecting a zero voltage of the AC power supply, the control unit and the operation unit encode an output signal of the induction heating unit control unit or the mode control unit into a digital signal having a predetermined number of digits, and Based on the output of the zero voltage detecting means, one digit of the digital signal is output until the next zero voltage point is reached after passing the zero voltage point, and the output content is output at least until the time passes near the next zero voltage point. And a demodulating means for inputting a signal near the zero voltage point based on the output of the zero voltage detecting means, and restoring a coded signal after inputting the signal to a predetermined number of digits. And an induction heating cooker configured to perform communication between the control unit and the operation unit. 2. The control section and the operation section each include modulation control means, wherein the modulation control means controls the modulation means so as to periodically perform signal transmission at a predetermined cycle, and controls the induction heating section control means or the induction heating section control means. 2. A configuration in which the latest input signal from the mode control means is held, and the latest input signal is outputted to the modulation means immediately before the start of signal transmission in the predetermined cycle or before the predetermined time. Induction heating cooker. 3. The control unit and the operation unit each include a determination unit that determines a match between a part or all of a received signal and a part or all of a signal transmitted immediately before reception of the signal, and the control unit includes the control unit. The control unit includes a control unit modulation control unit that controls the modulation unit of the control unit to start modulation and transmission immediately after the determination unit of the unit determines the signal or after a predetermined time, and the operation unit performs signal transmission. The modulation unit of the control unit performs the signal transmission after the completion of the signal transmission of the modulation unit of the operation unit after the completion of the signal transmission by the modulation unit of the operation unit after the completion of one signal transmission and the start of the next signal transmission. An operation unit modulation control unit that controls a modulation unit of the operation unit so as to be equal to or longer than a time until the transmission is completed, and the induction heating unit control unit or the mode control according to a determination result of the determination unit. Induction heating cooker of claim 1, wherein the configured to perform communication abnormality processing by the step. 4. A control unit and an operation unit for determining an abnormality of the zero voltage detecting means, and a communication partner abnormality detecting means for detecting an abnormality of the zero voltage detecting means on the communication partner side based on an input signal. The modulation means fixes the output to a predetermined logic according to the input from the zero voltage abnormality determination means, and performs the communication partner abnormality processing by the induction heating unit control means or the mode control means according to the output of the communication partner abnormality detection means. The induction heating cooker according to claim 2, wherein the cooking is performed. 5. The control section and the operation section each include a communication disconnection detecting means for detecting a disconnection of a communication line connecting the modulation means and the demodulation means, and the induction heating section control means or the induction heating section control means in accordance with an output of the communication disconnection detecting means. 3. The induction heating cooker according to claim 2, wherein the communication line disconnection processing is performed by the mode control means.