KR0128243Y1 - Control circuit for high frequency device - Google Patents

Abstract

The present invention relates to a high-frequency heating device control circuit, the conventional high-frequency heating device to increase the count value by one step by comparing the current average value and the output set value of the magnetron for each cycle of the commercial power supply it takes a long time to transition to the normal state In addition, there was a problem that the output of the magnetron gradually approaches the setpoint according to the change of the output setpoint.

In order to solve this problem, the present invention increases and decreases the count value by 2 clocks per cycle of commercial power when the output value of magnetron and the set value are different. You can expect.

Description

High Frequency Heating Device Control Circuit

1 is a block diagram of a conventional high frequency heating device.

(A) to (d) of FIG. 2 are output waveform diagrams of the parts of FIG.

3 is a block diagram of the high frequency heating device control circuit of the present invention.

(A)-(g) of FIG. 4 is an output waveform diagram of each part about FIG.

* Explanation of symbols for main parts of the drawings

1: rectification / smoothing part 2: inverter part

3: high frequency generation unit 4: driving unit

5 synchronous detection unit 6 current detection unit

7: output setting unit 8: comparator

9: register increase and decrease unit 10: synchronization signal generator

11: register 12: counter

13 clock generator 14 flip-flop

15: count value adjusting unit 16: comparator

17: clock generation controller 18: clock generator

The present invention relates to a high frequency heating apparatus, and more particularly, to a high frequency heating apparatus control circuit that allows the system to respond quickly to changes in the output set value when the set output and input are largely different.

FIG. 1 is a schematic diagram of a conventional high frequency heating device. As shown therein, a rectifying / smoothing unit including a bridge diode BD ₁ , a check coil CL ₁ , and a condenser C ₁ is provided to rectify and smooth the commercial power AC. (1) and the capacitor (C ₂ ), the diode (D ₁ ) so that the high frequency voltage corresponding to the output signal of the rectifying / smoothing unit (1) on / off by the driving signal of the driving unit (4) on the secondary side , The inverter (C ₃ ), the diode (D ₂ ), the magnetron so as to oscillate the high frequency signal by the output signal of the inverter unit (2) and the transistor (Q ₁ ) and the transformer (T). A high frequency generator 3 composed of MAG, a synchronous detector 5 for detecting a synchronous detection signal from the output signal of the inverter 2, and a magnetron MAG at every cycle of the commercial power source AC. A current detector 6 for detecting an average value of the current flowing through it, an output setting unit 7 for setting an arbitrary output value, and the current detection A comparator 8 for comparing the output signal of the output section 6 and the output setting section 7 and the output signal of the comparator 8 in synchronization with the synchronous signal of the commercial power source output from the synchronous signal generator 10. Therefore, the register increasing / decreasing unit 9 which increases or decreases the count value set in the register 11 and the count value set in the register 11 are counted in reverse in synchronization with the clock signal output from the clock generator 13. A counter 12 and a flip-flop 14 which is set / reset in accordance with the output signals of the counter 12 and the synchronous detector 5 to control the driver 4.

In the conventional high frequency heating apparatus configured as described above, the commercial power source AC is rectified by the bridge diode BD ₁ of the rectifying / smoothing unit ₁ and then smoothed by the condenser C ₁ , thereby providing a transformer T of the inverter unit 2. It is applied to the primary coil L ₁ . The inverter unit 2 generates a high frequency voltage to the transformer T secondary side coils L ₂ , L ₃ , and L ₄ by turning on and off the transistor Q _{1 in response} to a drive signal of the driving unit 4. When the high frequency voltage is rectified by the diode D ₂ of the high frequency generator 3 and applied to the magnetron MAG, the magnetron MAG oscillates a high frequency to heat the heated object.

At this time, if a signal such as (a) of FIG. 2 is generated in the secondary coil L ₄ of the transformer T by the resonant synchronization of the inverter unit 2, the synchronous detection unit 5 synchronizes with the signal. When a zero cross sync detection signal as shown in FIG. 2B is detected, and the flip-flop 14 is set at the falling edge of the sync detection signal, the driving unit 4 operates and the second unit is operated. As shown in FIG. 3D, the transistor Q ₁ of the inverter unit 2 is turned on.

On the other hand, from the high frequency voltage generated in the secondary coil L ₃ of the inverter unit 2, the current detector 6 detects the average value of the current flowing in the magnetron MAG at each cycle of the commercial power source AC, and compares the comparator ( When applied to the inverting terminal (-) of 8), the comparator 8 receives the output set value arbitrarily set by the output setting unit 7 as the non-inverting terminal (-), compares the average value with the set value, and generates a synchronization signal. The register increase / decrease unit 9 operating in synchronization with the commercial power source of the unit 10 detects the output signal of the comparator 8 and increases or decreases the count value of the register 11 by one step. If the average value is smaller than the set value of the output setting unit 7, the step value is increased. If the average value is larger than the set value, the value is decreased by one step. At this time, when the synchronous detection signal of the synchronous detection unit 5 is detected and reaches the falling edge as shown in (b) of FIG. 2, the count value of the register 11 is preset to the counter 12. (12) starts counting down the preset count value in synchronization with the clock signal output from the clock generator (13).

When the counter 12 completes the reverse count, when the completion signal is output as shown in (c) of FIG. 2, the flip-flop 14 is reset at the positive edge of the completion signal.

As a result, the driving unit 4 does not operate, and thus the transistor Q ₁ of the inverter unit 2 is turned off as shown in FIG.

At this time, the off time of the transistor Q ₁ is determined by the primary side coil L ₁ and the capacitor C ₁ of the inverter unit 2, and the inverter unit 2 is controlled by the synchronous detection signal of the synchronous detection unit 5. ) And the on-off synchronous of the transistor Q _1A .

That is, if the average value of the current for heating the heated object is smaller than the set value, the count value of the resistor 11 is increased to increase the switching time of the transistor Q ₁ , thereby increasing the output of heating the heated object, and If the average value is larger than the set value, the count value of the resistor 11 is decreased to reduce the switching time of the transistor Q ₁ , thereby reducing the output of heating the heated object.

However, as described above, the conventional high frequency heating apparatus takes a lot of time to operate in a steady state because it adjusts the count value by comparing the average value of the current flowing through the magnetron with the period of the commercial power supply arbitrarily set. There was a problem that the output of the magnetron slowly follows the set value as the change of.

In order to solve this problem, the present invention increases the count value by two clocks when the average value and the set value are compared for three consecutive periods of the commercial power synchronous signal. If it is not a value, the clock value is increased by one clock to shorten the time to reach a steady state, and a high frequency heating device control circuit is designed to respond quickly to a change in the set value. As follows.

The third turn and also a subject innovation high-frequency heating device control circuit configuration, thereby showing, as configured by a bridge diode (BD _1), check coils (CL _1), a capacitor (C ₁₎ rectifying and smoothing a commercial power source (AC) And a rectifier / smooth portion 1, a capacitor C ₂ , a diode D ₁ , a transistor Q ₁ , and a transformer T, which are turned on and off in response to a drive signal of the driver 4. And an inverter unit 2 generating a high frequency voltage corresponding to the output signal of the smoothing unit 1 on the secondary side, and a capacitor C ₃ , a diode D ₂ , and a magnetron MAG. The high frequency generator 3 for oscillating high frequency by the output signal of 2), the synchronous detection unit 5 for detecting the synchronous detection signal from the output signal of the inverter unit 2, and each cycle of the commercial power supply AC. A current detection unit 6 for detecting an average value of the current flowing through the magnetron MAG, an output setting unit 7 for setting an arbitrary output value, The output signal of the current detection unit 6 and the output setting unit 7 in synchronization with the output signal of the synchronization signal generator 10 and the synchronization signal generator 10 that generates a synchronization signal of the commercial power source AC. A count value adjusting unit 15 for adjusting the count value of the register 11 by comparing the output signal of the < RTI ID = 0.0 >)< / RTI > The counter value set in (11) is set / reset on the counter 12 which reversely counts in synchronization with the clock signal of the clock generator 13, and the output signals of the synchronous detection unit 5 and the counter 12. And a flip-flop 14 for driving the driving unit 4, and the count value adjusting unit 15 of the comparator 8 for three consecutive periods of the commercial power synchronization signal output from the synchronization signal generating unit 10. The control signal for clock generation is generated by determining the output change and And a clock generation controller 20 for generating a count value adjustment signal for increasing and decreasing the count value of the master 11, and a clock generator 30 for generating a clock according to the control signal of the clock generation controller 20. .

When described in detail with reference to the accompanying drawings the effect of the present invention configured as described above.

The commercial power source AC is rectified in the bridge diode BD ₁ of the rectifying / smoothing unit 1 and then smoothed by the capacitor C ₁ to transformer T of the inverter unit 2 primary coil L ₁ . Is applied to the inverter unit 2, and the transistor Q ₁ is turned on and off in response to the drive signal of the driving unit 4, thereby applying a high frequency voltage to the transformer T secondary side coils L ₂ , L ₃ and L ₄ . When the high frequency voltage is rectified by the diode D ₃ of the high frequency generator ₃ and then applied to the magnetron MAG, the magnetron MAG oscillates a high frequency to heat the heated object.

At this time, when a signal such as (a) of FIG. 4 is generated at the secondary coil L ₄ of the transformer T by the resonant synchronous of the inverter unit 2, the synchronous detection unit 5 generates a fourth signal from this signal. As shown in FIG. 2B, a synchronous detection signal of zero cross is detected. Accordingly, the flip-flop 14 is set at the falling edge of the synchronous detection signal, and the driving unit 4 is operated to turn on the transistor Q ₁ of the inverter unit 2 as shown in FIG.

On the other hand, at the high frequency voltage generated in the secondary coil L ₃ of the inverter unit 2, the current detector 6 detects the average value of the current flowing through the magnetron MAG at each cycle of the commercial power supply.

At this time, the comparator 16 of the count value adjusting unit 15 is synchronized with the synchronizing signal of the commercial power output from the synchronizing signal generator 10 and the average value of the current detector 6 and the output set value set by the output setting unit 7. The clock generation control unit 17 determines the output of the comparator 16 in synchronization with the output signal of the synchronization signal generation unit 10, and then counts the clock control signal and the register 11 to determine the number of clocks. Outputs a count value adjustment signal that increases or decreases the value.

Accordingly, the clock generation unit 18 generates a clock according to the clock control signal output from the clock generation control unit 17. As shown in (c) of FIG. When outputted with the same value as shown in (d) of FIG. 4, the clock generator 18 generates two clocks as shown in (ea) of FIG. 4, and the output of the comparator 16 is not outputted with the same value. The clock generator 18 generates one clock as shown in FIG.

Accordingly, the count value of the register 11 is adjusted by the clock control signal of the clock generation control unit 17 according to the clock signal of the clock generation unit 18.

The count value thus adjusted is preset to the instantaneous counter 12 at which the synchronous detection signal of the synchronous detection unit 5 is detected and becomes the falling edge as shown in FIG. 4B, and the clock generator 13 In response to the clock signal generated from the counter 12, the counter 12 starts the counter and outputs the completion signal as shown in FIG. 4 (f) when the counter is completed. At this time, at the rising edge of the completion signal, the flip-flop 14 is reset so that the transistor Q ₁ of the inverter unit 2 is turned off as shown in FIG.

As described above, if the current flowing through the magnetron differs from the output set value by increasing the count value by 2 clocks, the time to reach the steady state can be shortened and a quick response to the change of the output set value can be expected. It works.

Claims (3)

The rectifier / smoothing unit 1 rectifies and smoothes the commercial power supply AC and on / off according to the driving signal of the driving unit 4 to generate a high frequency voltage corresponding to the output signal of the rectifying / smoothing unit 1. An inverter unit 2, a high frequency generator 3 for oscillating high frequency in response to the output signal of the inverter unit 2, and a synchronous detection unit for detecting a synchronous detection signal from the output signal of the inverter unit 2; 5), a current detector 6 for detecting an average value of the current flowing in the output signal of the inverter unit 2, an output setting unit 7 for setting an arbitrary output value, and a synchronous signal for commercial power supply. The output signal of the current detector 6 and the output setting unit 7 is compared with the synchronization signal generator 10 and the output signal of the synchronization signal generator 10, and then a clock signal is generated according to the comparison value. And a count value adjusting unit 15 for generating a count value adjusting signal to adjust the counter value of the resist 11, A counter 12 which counter-counts the count value set in the gist 11 in synchronization with the clock signal of the clock generator 13, and sets / resets according to the output signals of the synchronization detector 5 and the counter 12. And a flip-flop (14) for driving the drive unit (4). The counter value adjusting unit (15) according to claim 1, further comprising: a comparator (16) for comparing the output signals of the synchronization detector (6) and the output setting unit (7) in synchronization with the output signal of the synchronization signal generator (10). And a clock generation control unit 17 for generating a clock control signal and a count value adjustment signal for controlling the number of clocks after determining the comparison signal of the comparator 16 in synchronization with the output signal of the synchronization signal generator 10. And a clock generator (18) for generating a clock according to the clock control signal of the clock generation controller (17). The control circuit of claim 1, wherein the clock generation controller 17 determines the output change of the comparator 16 during a predetermined period of the commercial power supply synchronization signal output from the synchronization signal generator 10. .