KR101846361B1 - Electric range having improved measurement and control of output - Google Patents

Abstract

According to the present invention, there is provided a power supply system comprising: a power supply unit for converting an AC power input from a commercial AC power source into DC power; A switching unit for generating high frequency power by switching the direct current power according to a predetermined high frequency switching signal; A heating unit that operates by the high-frequency power to induction-heat an object; An output measuring unit for measuring a voltage value and a current value of the high frequency power applied to the heating unit; And a microcomputer for controlling an induced heating output amount by controlling an attribute of the high frequency switching signal applied to the switching based on the voltage value and the current value measured by the output measuring unit The electric range is started.

Description

ELECTRIC RANGE HAVING IMPROVED MEASUREMENT AND CONTROL OF OUTPUT BACKGROUND OF THE INVENTION < RTI ID = 0.0 > [0001] <

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating type electric range, and more particularly, to an electric range in which an induction heating output amount is fed back to control an induction heating output amount.

BACKGROUND ART [0002] In recent years, an electric range for heating and cooking an object by using electricity, which is clean energy, has become widespread.

The electric range operates on the principle of converting AC power into high-frequency DC power, forming a high-frequency electromagnetic field in the working coil by the converted high-frequency DC power, generating an eddy current in the object to be heated by the electromagnetic field, do.

Fig. 1 is a block diagram for explaining the structure and operation of such a general induction heating type electric range. The electric range may include a power supply unit 10, a switching unit 20, a heating unit 30, a microcomputer unit 50, and an output measurement unit 40.

The power supply unit 10 converts AC power received from a commercial AC power source into DC power. To this end, the power supply 10 may include a diode bridge circuit.

The switching unit 20 generates high-frequency power by switching the direct-current power output from the power supply unit 10 according to a predetermined high-frequency switching signal. The generated high-frequency electric power is supplied to the heating unit 30.

The heating unit 30 may include a working coil, and the working coil induction-heats the object by the high-frequency power generated by the switching unit 20. [

The microcomputer unit 50 controls the output of induction heating by generating and adjusting a high frequency switching signal corresponding to a user's operation or in response to a self-stored heating algorithm.

On the other hand, in a general electric range, the voltage value of DC power is measured at one side of the power supply unit 10, the current value used for induction heating at one side of the heating unit 30 is measured, and the electric power The amount of consumption (that is, the amount of induced heating output) was calculated.

On the other hand, the measured induction heating output is an important feedback element for controlling the high frequency switching signal when the object is continuously heated at a constant output amount or heated to a specific output amount.

Therefore, it is important to accurately measure the current induced heating output.

However, in a typical electric range, since the point at which the voltage value is measured and the point at which the current value is measured are different from each other, accurate induction heating output can not be calculated.

2 is a view for explaining a method of measuring voltage and electric power in a general electric range.

As described above, in a general electric range, the voltage measuring means 41 is connected in parallel at one side of the power supply unit 10, that is, at any point between the power plug and the diode bridge circuit to measure the voltage value of the AC power .

In addition, an output side (high-side switching element Q1 and low-side switching element Q2) for outputting high-frequency power from the switching unit 20, particularly between the connection ends 38 and 39 between the switching unit 20 and the heating unit 30, (A connecting point of the heating coil Q2) and the connecting end 39 of the heating coil 30 and the current measurement means 42 is connected in series to measure the current value acting on the induction heating .

The measured voltage value and current value may be transmitted to the microcomputer 50 and calculated as a power value.

However, as described above, in a general electric range power measurement method, since the voltage value is measured by the power supply unit and the current value is measured by the heating unit, accurate power consumed in induction heating can not be calculated.

Accordingly, the present invention provides an electric output measuring and control type electric range which can accurately calculate the amount of electric power consumed for performing induction heating and can accurately control the amount of induction heating by accurately measuring the amount of electric power I want to.

According to an aspect of the present invention, there is provided an electric range of an improved output measurement and control system including: a power supply unit for converting AC power received from a commercial AC power source into DC power; A switching unit for generating high frequency power by switching the direct current power according to a predetermined high frequency switching signal; A heating unit that operates by the high-frequency power to induction-heat an object; An output measuring unit for measuring a voltage value and a current value of the high frequency power applied to the heating unit; And a microcomputer controlling the induction heating output amount by controlling the high frequency switching signal applied to the switching based on the voltage value and the current value measured by the output measuring unit.

Here, the switching unit includes an upper switching element and a lower switching element connected in series to each other, the DC power is supplied to the input side of the upper switching element, and the connection point of the upper switching element and the lower switching element is the high- Wherein the microcomputer is connected to the heating unit by switching the switching device on every at least one of an upper high frequency switching signal to be provided to the upper switching device and a lower high frequency switching signal to be provided to the lower switching device The on-time heating output amount of the heating unit can be controlled by changing the ON time for turning on the heating unit.

The output measuring unit may include a current measuring unit connected in series between the connection point and the input unit of the heating unit and a voltage measuring unit connected in parallel between the connection point and the input terminal of the current measuring unit.

The electric range of the improved output measurement and control method according to the present invention configured as described above can measure the voltage value and the current value of the high frequency power applied to the heating unit that actually performs induction heating, The amount of output can be calculated.

Thus, the high-frequency switching signal appropriately adjusted by the accurately measured induction heating output amount can be generated, so that the operation of the heating unit can be accurately controlled.

1 is a block diagram for explaining the construction and operation of a general induction heating type electric range.
2 is a view for explaining a method of measuring voltage and electric power in a general electric range.
3 is a diagram schematically showing a configuration of an electric range according to the present invention configured to accurately measure a voltage value and a current value of a high frequency electric power to control an induction heating output amount.
4 is a diagram showing an example of the configuration of the output measuring unit.
5 is a signal waveform diagram for explaining a method of controlling a heating output amount in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of an improved electric power measurement and control type electric range according to the present invention will be described with reference to the accompanying drawings. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting.

FIG. 3 is a diagram showing a schematic circuit configuration of an electric range according to an embodiment of the present invention. The voltage value and the current value of high frequency power applied to the working coil are accurately measured, and the measured value is fed back, FIG. 2 is a view showing a configuration of an electric range according to the present invention, which is configured to accurately control an electric current.

The basic configuration and operation of the power supply unit 101, the switching unit 20, the heating unit 30, and the micom unit 50 are the same as those of a general electric range.

However, in the electric range according to the present invention, the output measuring unit 40 is disposed between the switching unit 20 and the heating unit 30. The output measuring unit 40 disposed here is capable of measuring the voltage and current of the high frequency power and is particularly preferably configured to measure the voltage and the current together at the same point (node).

Since the induction heating is performed by the working coil of the heating unit 30, it is possible to measure the voltage and the current in the vicinity of the working coil to obtain the most accurate induction heating output amount You can get it.

The microcomputer 50 can calculate the accurate power consumption by the working coil of the heating unit 30 by using the measurement value of the output measuring unit 40. The microwave unit 50 can thus calculate the high frequency It becomes possible to control the attribute of the switching signal. The controllable attributes may include the switching frequency and the width of the on time per period of the switching signal.

For reference, the term "power" as used herein is used as a term to include both "current" and / or "voltage ". For example, DC power may mean DC voltage and / or DC current. Also, the power supply unit should be understood as a component that generates a DC voltage and / or a DC current from a commercial AC power source and applies it to the switching unit. Likewise, high frequency power may mean both high frequency voltage and / or current generated by high frequency switching of the direct current voltage.

4 is a diagram showing an example of a configuration of an output measuring unit arranged to measure a voltage value and a current value of high frequency power between the switching unit and the heating unit as in the above embodiment. In the circuit diagram shown in the circuit diagram, the switching unit 20 is configured such that two switching elements (upper switching element Q1 and lower switching element Q2) are connected in series to each other and DC power is applied to the input side of the upper switching element Q1 Bridge structure in which the working coil of the heating section 30 is connected to the output side of the high-frequency power which is the connection point of the upper switching element Q1 and the lower switching element Q2.

The switching unit 20 can apply not only this method but also a full bridge type connection configuration.

Both ends of a working coil (not shown) may be coupled between the terminal 39 extending from the output side of the switching unit 20 and the terminal 38 on the ground side.

Meanwhile, the output measuring unit 40 may be disposed between the switching unit 20 and the terminal 39. The output measuring unit 40 includes a voltage measurement unit 41 connected in parallel from a node connecting the connection point of the switching unit 20 and the terminal 39 and a voltage measurement unit 41 connected between the connection point of the switching unit 20 and the terminal 39 And a current measuring means 42 connected in series.

Thus, the output measuring unit 40 according to the present invention is configured to measure the voltage value and the current value at the same point. The voltage and current measured at this time may be the voltage and current of the high frequency power applied to the heating unit 30. Therefore, the power consumed by the working coil of the heating section 30, that is, the induction heating output amount used for the high-frequency power can be accurately measured.

The microcomputer 50 may use the voltage value and the current value to generate a high frequency switching signal for controlling the switching unit 20. [ That is, by receiving the measured voltage value and the current value, it is possible to adjust the property of the high frequency switching signal that is currently output.

The adjustable attribute may include the switching frequency and the width of the time that the switching element is turned on in each period of the switching signal. In particular, in the case of adjusting the width of the turn-on time of the switching signal, it is preferable to adjust the width of the high-frequency switching signal to be provided to the upper switching element Q1.

Such control will be described with reference to Fig. 5 is a signal waveform diagram for explaining a method of controlling the heating output amount by changing the ON time width of each cycle of the high frequency switching signal.

5 (a) shows a waveform of a high-frequency switching signal having a frequency of, for example, 21 kHz. In the induction heating circuit of the half bridge current resonance method, the actual induction heating output is controlled by the operation of the upper switching device Q1, and the operation of the lower switching device Q2 is substantially independent of the output. Therefore, in the present invention, the on-time of the upper switching element Q1 is mainly controlled, and the on-time of the lower switching element Q2 can be arbitrarily determined within a range not overlapping with the on-time of the upper switching element Q1 .

5A shows that the on-time pulse width D1 is 50% at a fixed frequency of 21 kHz (in this 50%, the dead time (the state of the upper switching element and the lower switching element is turned on simultaneously Delay time to set non-overlapping). Since the lower switching element Q2 must be kept on for a time equal to or longer than the time when the upper switching element Q1 is turned on, if the on time of the upper switching signal is 50% of the cycle, Output can be output. The output at this time may be 1800 W, for example.

When the output of the working coil is to be reduced during the maximum output as described above, the switching frequency can be changed. However, as shown in Fig. 5 (b), the on- . Here, it is shown that the on-time pulse width D2 is reduced to about 20% of one cycle. The induction heating output at this time may be, for example, 400W.

Since the on time of the upper switching signal is reduced, the off time of the upper switching device Q1 will be longer. At this time, the on-time of the lower switching signal can be arbitrarily determined within the off-time range of the upper switching signal.

By reducing the on-time of the upper switching signal, the current of the high-frequency power applied to the working coil is reduced, and as a result, the output of the induction heating is reduced.

Fig. 5 (c) shows a case in which the output of the working coil is further reduced. It can be seen that the on-time (D3) of the upper switching signal is reduced to 10% of one period, and the output at this time may be 300W. The on time of the lower switching signal can be arbitrarily set within the off time range of the upper switching signal.

The embodiments of the present invention described above are merely illustrative of the technical idea of the present invention, and the scope of protection of the present invention should be interpreted according to the claims. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the essential characteristics thereof, It is to be understood that the invention is not limited thereto.

Claims (3)

A power supply unit for converting AC power received from a commercial AC power source into DC power;
A switching unit for generating high frequency power by switching the direct current power according to a predetermined high frequency switching signal;
A heating unit that operates by the high-frequency power to induction-heat an object;
An output measuring unit for measuring a voltage value and a current value of the high frequency power applied to the heating unit from the switching unit;
And a microcomputer section for controlling the induction heating output amount by controlling the high frequency switching signal applied to the switching section based on the voltage value and the current value measured by the output measuring section. Of electric range. The method according to claim 1,
Wherein the switching unit includes an upper switching device and a lower switching device connected in series to each other, the DC power is supplied to the input side of the upper switching device, and the connection point of the upper switching device and the lower switching device is connected to the output side of the switching part And connected to the heating unit,
The microcomputer may change an on time (ON time) for turning on the switching element every at least one of an upper high frequency switching signal to be provided to the upper switching element and a lower high frequency switching signal to be provided to the lower switching element Wherein the control unit controls the amount of induction heating output of the heating unit. 3. The method of claim 2,
Wherein the output measuring unit comprises:
A current measuring means connected in series between the connection point and the input of the heating unit and a voltage measuring means connected in parallel between the connection point and the input of the current measuring means. Electric range.

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