JP2586872Y2 - High frequency heating equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically adjusting a high-frequency output of a high-frequency heating device for driving a magnetron by an inverter circuit.

[0002]

2. Description of the Related Art An inverter circuit is provided which rectifies a commercial AC power supply and converts the rectified AC power into AC power having a frequency (several tens of kHz) corresponding to a high-frequency output set by a customer by turning on and off a switching element. In a high-frequency heating device that supplies power to the inverter, as means for sending setting output data to the control circuit of the inverter circuit, a microcomputer reads data corresponding to the setting output from the internal ROM, and this data is used as it is as setting output data. A method of transmitting the signal to a control circuit is used.

[0003]

However, in this method, setting output data is stored in a mask RO in a microcomputer.
Since it is stored in M, it cannot be changed. Considering the characteristic variations of products, it is very difficult to obtain the same specified high-frequency output for all products with this uniformly determined output data.

For this reason, conventionally, it is necessary to provide a hardware or software adjusting means in consideration of the heating efficiency and the variation of the circuit constant, so that a fine adjustment volume is usually provided in the control circuit of the inverter. In this method, a current value supplied from a commercial power supply to an inverter circuit is detected, and the detected current value is adjusted to a value corresponding to a specified output by the above-described volume.

[0005] However, this adjustment operation is very troublesome because the above-mentioned current value must be measured while turning a small volume.

Further, since the volume is mounted on a substrate on which an inverter circuit is formed, the adjustment of the volume must be performed without mounting a product cabinet, and cannot be adjusted when the product is completed. There was a difficult point. Input current measuring means for an inverter circuit having a switching element for supplying power to a magnetron, as an adjustment work utilizing various keys provided on an operation unit in order to eliminate such difficulties, An inverter control circuit configured to include a microcomputer, and adjusting the power supplied to the magnetron so that the current detection signal by the input current measurement unit has a required value, and a nonvolatile memory accessed by the microcomputer, Some microcomputers are configured to have means for performing feedback control of the power supplied to the magnetron based on the data stored in the nonvolatile memory and the current detection signal.

Further, the microcomputer calculates a "control constant" from an actual measurement input to the inverter circuit at the time of magnetron oscillation and a current detection signal output by the input current measuring means at that time, and the "control constant". "
Is stored in a non-volatile memory, and there is provided a means for feedback-controlling the power supplied to the magnetron based on the “control constant” stored in the non-volatile memory.

In the former, data (signal level at that time) corresponding to the state of the current detection signal output from the input current measuring means when the rated input current actually flows through the inverter circuit is written in the nonvolatile memory in advance. When the microcomputer receives, for example, a signal for oscillating the magnetron at the rated output, the microcomputer accesses the non-volatile memory to read the previously written data.
(Signal level), and compares the read signal level with the signal level of the current detection signal.If the signal level of the current detection signal is lower than the signal level of the read data, the nonvolatile memory Is multiplied by a coefficient corresponding to the ratio of “former / latter” to lengthen the on-time of the switching element. Conversely, when the latter is higher than the former, the data is given “former / latter”. The on-time of the switching element is shortened by multiplying by a coefficient corresponding to the ratio, and the on-time of the switching element is determined so that both the specified rated output value of the magnetron and the actual output value of the magnetron are equal to each other. The input current is immediately set to the rated current.

In the latter case, when a microcomputer receives a signal for oscillating a magnetron at a rated output, for example, it accesses a non-volatile memory and reads out a "control constant" stored therein, and from the input current measuring means every moment. The value of the output current detection signal is multiplied by the “control constant” to calculate the actual input current value flowing into the inverter circuit, and the calculated input current value is compared with the rated input current value. When the ON time of the switching element is longer than the former when it is lower, the ON time of the switching element is determined so that the ON time of the switching element is shorter when the latter is higher than the former, and the ON time of the switching element is equal to the former. The input current is immediately set to the rated current. (See Japanese Patent Application Laid-Open No. 3-167779) This configuration is based on the premise that the inverter circuit that feeds back the input always operates correctly, and is established if the "variation" of the inverter circuit is large. I can't get it.

Further, the operation of adjusting the high-frequency output value of the magnetron is performed while measuring the current during the operation of the magnetron immediately after assembling the product. Since the adjustment is performed by operating two keys at the same time, there is a problem that the operator is completely involved until the adjustment operation is completed.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and comprises a magnetron driven by a high-frequency power source formed by an inverter circuit, and a microcomputer for controlling the driving of the magnetron. A writable / readable nonvolatile memory storing data corresponding to each high-frequency output value of a magnetron external to a microcomputer, and a current input to the microcomputer by detecting a current value supplied to an inverter circuit A detection circuit, and a keyboard provided with a key A and a key B and connected to a microcomputer, and the above-mentioned current value corresponds to each of the above-mentioned high-frequency output values of the magnetron at the time of a specific input operation of the keys A and B. Stored in non-volatile memory to fall within the specified range It is obtained so as to automatically re-set the over data.

[0012]

In this manner, when heating and cooking are started with an arbitrary high-frequency output value set, the microcomputer sets out of the data corresponding to each high-frequency output value of the magnetron stored in the non-volatile memory. The data corresponding to the set high-frequency output value is read and sent to the inverter circuit, and the inverter circuit causes the magnetron to start an oscillating operation based on the set high-frequency output value data.

When the microcomputer operates the self-adjustment function of the high-frequency output value, a key input operation based on a specific sequence is performed, and the current value (the former) measured by the current detection circuit is set to the set high-frequency output value. Compare with the current value of the corresponding data (the latter).

When the former is out of the latter range, the microcomputer sends back data obtained by subtracting one from the data value stored in the non-volatile memory to the inverter circuit as setting output data, and conversely, the former is the latter. When the value is smaller than the value, the data obtained by adding 1 to the data value stored in the nonvolatile memory is sent back to the inverter circuit as the setting output data.

This operation is repeated until the former falls within the latter prescribed range. When the former falls within the latter prescribed range, the data is stored in the nonvolatile memory as new setting output data and the data is stored. Update.

The updated new output data corresponding to each of the high-frequency output values of the magnetron is stored in the non-volatile memory during the magnetron oscillation operation and immediately transmitted to the inverter circuit. Easy operation by key operation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a high-frequency heating device showing one embodiment of the present invention, and FIG. 2 is a diagram showing the flow of main signals and data.

In FIG. 1, reference numeral 1 denotes a microcomputer, and the microcomputer 1 is provided with an externally readable / writable nonvolatile memory 2. Reference numeral 3 denotes an inverter circuit including a full-wave rectifier circuit 4, a magnetron driving transformer 5, a capacitor 6, a diode 7, a switching element 8, and the like, and a microcomputer 1 via an element control circuit 9 for controlling the switching element 8 to turn on and off. It is connected to the.

The element control circuit 9 includes the nonvolatile memory 2
Is written via the microcomputer 1 in synchronization with the clock signal CLK as the data signal DATA, in which the central value of the product variation corresponding to each high-frequency output value of the magnetron 10 stored in the memory 1 is written.

The nonvolatile memory 2 specifies data reading by a read enable signal RE from the microcomputer 1 and data writing by a write enable signal WE, and specifies data addresses by address signals AD0 to AD5, respectively. This is performed by data input / output signals D0 to D5.

Numeral 11 denotes a current detecting circuit comprising a current transformer 11a for detecting a current value inputted from the commercial power supply 12 to the inverter circuit 3 and a rectifying / smoothing circuit 11b for converting the output voltage into a DC voltage. It is input to the A / D converter of the microcomputer 1.

Reference numeral 13 denotes a keyboard, which is a key A operated according to a specific sequence when resetting the output value of the magnetron 10.
14 (hereinafter "Start" key), key B15 (hereinafter "Cancel")
Key) and various key switches (description omitted) that are operated when the high-frequency heating device is operated.

Next, the operation of this embodiment will be described.

When the output of the magnetron 10 is adjusted, for example, 500 W is selected and set, for example, from the respective high-frequency output values of the magnetron 10 to be adjusted, and the magnetron 10 is turned on.

Here, the selected high-frequency output value (5
It is assumed that, for example, a standard value 24H in consideration of product variations is stored in a certain address of the nonvolatile memory 2 as data corresponding to (00W).

After the start, as shown in FIG. 2, the chip select signal CS from the microcomputer 1 becomes HIGH.
, And the nonvolatile memory 2 enters an active state.

At the same time, the read enable signal RE becomes HI
Since it is GH, the nonvolatile memory 2 is in a read state.

Therefore, the microcomputer 1 obtains the data 24H from the nonvolatile memory 2 by referring to the address corresponding to the above-mentioned set value.

By starting transmission of the data 24H to the element control circuit 9 as a data signal DATA in synchronization with the clock signal CLK, the switching element 8 in the inverter circuit 3 starts driving.

When the switching element 8 starts to be driven, the inverter circuit 3 starts operating, and a current flows through the magnetron driving transformer 5. The high-frequency power generated by the inverter circuit 3 is supplied to the magnetron 10 and the magnetron 10 is driven. Starts operation.

Here, when the self-adjustment function of the microcomputer 1 is operated, the " start " key 14 and the "cancel" key 15 are respectively switched from the switch group of the keyboard 13 to the "start" key 14 → "cancel" key 15. → "Start" key 14 →
Input alternately in the order of "Cancel" key 15.

When the above-described key operation is performed after the operation of the inverter circuit 3 is started, the microcomputer 1 outputs the chip select signal CS and the read enable signal R
E is set to LOW, and reading from the nonvolatile memory 2 is stopped.

Next, the microcomputer 1 A / D converts the input from the current detection circuit 11 to calculate a current value supplied from the commercial power supply 12 to the inverter circuit 3, and calculates the current value and the above-mentioned set value. The current value in the specified range is compared with the 500 W output.

Assuming that the calculated current value exceeds the current value in the above-defined range, the microcomputer 1 changes the data to 23H, sends the data to the inverter circuit 3 again, and returns from the current detection circuit 11 again. Calculate the current value by inputting.

This operation is repeated until the calculated current value falls within the specified range.

Assuming that the calculated current value falls within the specified range when the microcomputer 1 changes the data to 20H by this repetitive operation, the microcomputer 1 outputs the data 20H to the high-frequency output value.
(500 W) as new setting output data, the chip select signal CS and the write enable signal WE.
Is set to HIGH to put the nonvolatile memory 2 in the write state, and the above-described data stored in the nonvolatile memory 2
(24H) is changed to new data (20H), and the microcomputer 1 writes the new data (20H) in the nonvolatile memory 2 at the same address storage location where the data (24H) was stored.

When the writing of the changed new data (20H) is completed, the microcomputer 1 changes the write enable signal WE to LOW and the read enable signal RE.
Is set to HIGH, the nonvolatile memory 2 is returned to the read state, new data (20H) is read, and the new data (2H) is read.
0H) to the inverter circuit 3.

On the other hand, if the calculated current value is below the specified range, the reverse operation is automatically performed by the microcomputer 1 so that the calculated current value falls within the specified range. 25H until data enters →
.., And the data (24H) stored in the nonvolatile memory 2 is changed.

As described above, the self-adjustment function of the microcomputer 1 is operated by a simple operation of the "start" key 14 and the "cancel" key 15 of the high-frequency output value of the magnetron 10, and the input current obtained by the current detection circuit 11 is obtained. The microcomputer 1 outputs the output data so that the value falls within a prescribed value corresponding to the data corresponding to the set high-frequency output value.
Can be changed automatically by the magnetron 10
Can be adjusted very easily.

[0041]

[Effects of the Invention] A nonvolatile memory that can store and read data corresponding to each high-frequency output value of a magnetron externally connected to a microcomputer that controls the driving of the magnetron, and an inverter that creates a driving power supply for the magnetron A current detection circuit that detects a current value supplied to the circuit and inputs the current value to the microcomputer; and a keyboard connected to the microcomputer and provided with keys A and B. Since the data corresponding to each high-frequency output value of the magnetron stored in the non-volatile memory can be automatically changed by the microcomputer through the current detection circuit by the operation, the trouble such as volume adjustment as in the related art can be eliminated. Output that could not be achieved without removing the cabinet Hakare be simplified adjustment work, also the regulatory work output that can be the ratio simply by key operation, also can be utilized in servicing not only the production line can provide a high frequency heating apparatus measurably also improve serviceability.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a high-frequency heating device showing one embodiment of the present invention.

FIG. 2 is a diagram showing flows of main signals and data. DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Nonvolatile memory 3 Inverter circuit 4 Full-wave rectifier circuit 5 Transformer for magnetron drive 6 Capacitor 7 Diode 8 Switching element 9 Element control circuit 10 Magnetron 11 Current detection circuit 12 Commercial power supply 13 Keyboard 14 Key A 15 Key B

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-167779 (JP, A) JP-A-4-84025 (JP, A) JP-A-5-41093 (JP, U) JP-A-5-41093 41095 (JP, U) Japanese Utility Model Hei 5-41094 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H05B 6/68 350 H05B 6/68 320

Claims (1)

(57) [Scope of request for utility model registration] 1. A full-wave rectifier circuit (4) for rectifying and smoothing a commercial power supply (12) to produce a DC power supply, a magnetron drive transformer (5), a capacitor (6), a diode (7), and a switching element ( 8) an inverter circuit (3) composed of:
A magnetron (10) driven by a high-frequency power supply generated by the inverter circuit (3) and supplied under the control of the switching element (8); and the switching element (8) driving the magnetron (10) is turned on / off. An element control circuit (9) for controlling the microcomputer, a microcomputer (1) for controlling the driving of the element control circuit (9), and an external device connected to the microcomputer (1) and transmitted to the element control circuit (9). A writable / readable nonvolatile memory (2) storing data corresponding to each high-frequency output value of the magnetron (10), and a current supplied from the commercial power supply (12) to the inverter circuit (3). a current detection circuit (11) to be input to the microcomputer so detects the value (1), before
Key A (14) connected to the microcomputer (1),
A keyboard (13) having keys B (15),
By the specific input operation of the key A (14) and the key B (15),
The microcomputer (1) determines that the current value is
The above-mentioned non-volatile range falls within the specified range corresponding to the output value.
The data stored in the memory (2) is automatically regenerated.
A high-frequency heating device characterized by setting .