JPH04106894U - High frequency heating device - Google Patents

Abstract

(57) [Summary] [Purpose] To easily determine whether an inverter circuit is malfunctioning. [Configuration] Current detection circuit 1 detects the anode current value of the magnetron.
6, converts it into a digital value, and inputs and transmits it to the microcomputer 13 through a communication circuit. In the inspection mode, the microcomputer displays the input value on the display only when a specific keyboard switch 19, for example, the "high range" switch, is pressed, and the displayed value is displayed to the person conducting the inspection. It is possible to determine whether there is a failure by determining whether or not the value corresponds to the set high frequency output.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a so-called inverter that drives a magnetron using an inverter circuit. The present invention relates to a high-frequency heating device equipped with a self-testing function for a motor drive circuit.

0002

[Conventional technology]

It rectifies the commercial AC power supply and sets it by the customer by turning the switching element on and off. This system is equipped with an inverter circuit that converts the high frequency output into AC power at a frequency corresponding to the high frequency output. In high-frequency heating equipment that supplies power to the magnetron using an inverter circuit. check whether the inverter circuit is operating normally at the set high frequency output. Conventionally, the method of checking is to measure the actual current and power values input to the inverter circuit. There was no choice but to measure it with a measuring device.

0003

[Problem that the idea aims to solve]

However, with this conventional example, ammeters and wattmeters for measuring current and power cannot be used. This is necessary and cannot be accomplished with simple tasks. Therefore, if there is no output at all This is not an extreme failure, but a failure where the high frequency output value differs from the set value. service personnel can easily measure this unless using the measuring instrument described above. I couldn't do it.

0004

[Means to solve the problem]

Easily test whether the inverter circuit is operating at the set high frequency output In order to do this, the anode current flowing through the magnetron is detected and converted into a digital value. This value is fed back to the microcomputer, and the microcomputer By displaying this input value on the display, the value corresponds to the set high frequency output. It is possible to determine whether the value corresponds to the specified value. Under normal conditions, this display is not displayed. Since it is not possible to display a display-only inspection mode for the microcomputer, The above-mentioned operation is performed in this mode during inspection.

[0005]

[Effect]

A current detection circuit detects the anode current flowing through the magnetron and converts it into a digital value. A communication device that converts the digital current value and transmits it to the microcomputer as an input value. Install a communication circuit. The microcomputer reads this input value when in inspection mode. and only when a specific key is input from the keyboard switch. Display the value on the display. The person conducting the inspection must ensure that the displayed value is the set high-frequency output. The presence or absence of a failure is determined by whether the value corresponds to the force.

[0006]

【Example】

An embodiment of the present invention will be described below.

[0007] FIG. 1 is a circuit diagram showing an embodiment of the present invention.

[0008] The microcomputer 13 controls the operation of the inverter circuit for the control circuit 9. Outputs the start signal P for instructing to stop, and also outputs the set output value of the high frequency output. is output as the data signal SD1.

[0009] Data signal SD1 is 16-bit serial data, based on transmission start signal S1. It is transmitted in synchronization with clock signal CLK. This signal is input to the communication circuit 14. , here it is converted to 6-bit parallel data by shift register 14a etc. and is transmitted to the comparator 9a of the control circuit 9 as setting data PD1. On the other hand, Magne The current flowing through the tron 12 is detected by the current transformer 17, which converts the current into The signal is input to the detection circuit 16. Here, the rectified and smoothed voltage Vin is applied to the A/D converter. Therefore, it is converted to 6-bit parallel data PD2, which is controlled via the latch. It is fed back to the comparator 9a of the circuit 9 as input data. In comparison section 9a is this feedback input data PD2 and the microcomputer 13? and the setting data PD1 sent from the introduce. Based on this fed back comparison result, the pulse width controller 9b controls P Pulse width of pulse signal D that drives switching element 7 so that D1=PD2 control and adjust the output.

0010 The communication circuit 15 is an input that is fed back from the current detection circuit 16 to the control circuit 9. Take in data PD2 and send it to selector 15a, binary counter 15b, etc. Therefore, as shown in Figure 2, it is converted to 6-bit serial data SD2 and sent to the microcontroller. The fall of the transmission start signal S2 is determined using the clock signal CLK from the computer 13. The data is sent to the microcomputer 13 based on the reference value.

[0011] The microcomputer 13 is operated by the specified input operation of the keyboard switch 19. In normal operating conditions, the 7-segment display on the display 18 The remaining heating time is displayed on the numerical display consisting of the In addition, while the "Range Strong" key on the keyboard switch 19 is pressed, the communication line is Input data SD2 input from path 15 is displayed. Therefore, the person conducting the test After the microcomputer 13 enters the inspection mode, any high-frequency output Set the power value and start the heating operation, and then display 1 when inputting "Microwave High". The value of input data SD2 displayed in It matches the value of the data signal SD1 transmitted from the computer 13 to the control circuit. It is possible to determine whether there is a failure or not.

0012

[Effect of the idea]

As described above, according to the present invention, it is possible to detect You can check the output difference of the inverter circuit just from the information displayed on the display. Inspection efficiency can be improved. In addition, as in the example, the control circuit is digital. Since it is composed of circuits, costs can be reduced by converting it to LSI, including communication circuits, etc. We can provide an excellent high-frequency heating device with a self-diagnosis function for inverter circuits. Ru.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a signal diagram of the communication section.

[Explanation of symbols]

9 Control circuit 13 Microcomputer 14 Communication circuit 15 Communication circuit 16 Current detection circuit 18 Display 19 Keyboard switch

Claims (1)

[Scope of utility model registration request] [Claim 1] A rectifier and smoothing circuit that rectifies and smoothes a commercial power source to produce a DC power source, a transformer, a capacitor, a diode,
An inverter circuit composed of switching elements,
A control circuit that controls on/off switching elements of the inverter circuit according to the set high frequency output, a magnetron driven by the high frequency power supply generated by the inverter circuit, and a microcontroller that transmits the set high frequency output to the control circuit. A computer, a keyboard switch that inputs input to the microcomputer, a current detection circuit that detects the anode current value of the magnetron, converts it into a digital value, and transmits it to the control circuit, and lights up according to a signal from the microcomputer. and a display device, further comprising a communication circuit for transmitting the digital value converted by the current detection circuit to the microcomputer as an input value, and an inspection mode for processing input from the communication circuit. is provided in the microcomputer, and when the microcomputer receives a specific key input from the keyboard switch during the inspection mode, the microcomputer displays the input value on the display.