JPS61195584A - Temperature controller for induction heating cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an induction heating cooker that generates a high-frequency alternating magnetic field and heats a load by induction by supplying high-frequency alternating current to a heating coil. The present invention relates to a temperature control device for the cooker.

(Naka) Conventional technology This kind of induction heating cooker was developed in Utility Model Publication No. 57-103694.
As disclosed in Japanese Patent Application Publication No. 57-107298, etc., a temperature sensing element is provided on the back side of the top plate to indirectly detect the temperature of the load by detecting the temperature of the top plate.

(c) Problems to be solved by the invention In the conventional technology described above, the temperature of the load is detected indirectly, so the detected temperature varies depending on the shape of the load (for example, the unevenness and size of the bottom surface), resulting in inaccurate detection. This method has the drawbacks of not being able to accurately detect temperature, and not being able to follow sudden changes in load temperature. In order to solve this problem, it is conceivable to provide a separate temperature sensing element at the tip of a probe or the like extending from the inside of the cooker to the outside of the cooker, or to insert the temperature sensing element directly into the load itself. However, the temperature-sensing part equipped with this temperature-sensing element may vary depending on the temperature of the oil (240° to 300°).
℃), and it is necessary to use a material with excellent thermal conductivity and heat resistance, so metal materials are generally suitable.

At this time, it is necessary to provide insulation between the temperature detection means such as a probe equipped with a temperature sensing element and the internal circuit of the cooker.
When conventional insulation is used, there is a problem in that a temperature gap occurs and the accuracy of temperature control deteriorates.

Therefore, the present invention provides a cooking appliance that is equipped with a temperature detection means for directly detecting the temperature of the load, thereby improving temperature control accuracy.

B) Means for Solving Problems The present invention includes a temperature setting section that specifies a set temperature for temperature control operation and converts the set temperature into an electrical signal, and a temperature setting section that directly detects the temperature of the load and converts the detected temperature. a temperature sensing element that converts into an electrical signal; a signal transmission means that is electrically insulated and transmits the signal from the temperature sensing element; and a signal transmission means that receives both the signal from the signal transmission means and the signal from the temperature setting section. and a temperature adjustment circuit that sends a signal to adjust the heating output of the heating coil, which is the source of induction heating, based on the state of the heating coil.

(The change in resistance value based on the temperature detected by the thermosensor for Hakui (6) is converted into an electrical signal, and this signal is transmitted to the temperature control circuit via the electrically insulated signal transmission means (27). death,
The set temperature set by the operating switch 03) is maintained by adjusting the heating output of the heating coil 03) in the inverter circuit 0υ using the output of the temperature adjustment circuit (29) based on the signal.

(F) Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(2) is a box-shaped cooking device body (1, 1) having a top opening and is arranged to close the top opening of 1 and is made of a heat-resistant insulating member such as ceramic glass for placing the load (3). The plate (4) is provided on the outer periphery of the top plate (2) and has an operation surface (5) with an operation section and a display section (to be described later), and extends from the inside of the main body (1) to the outside and has a sensing section at the tip. On element (6)
It is an outer frame equipped with a jack sleeve (9) for inserting the temperature-sensitive probe (force plug part (8)).

The operation surface (5) consists of the following: a power switch (11), a power confirmation lamp that lights up when the power switch (Q0) is turned on, and (11) a selection switch for selecting the cooking operation mode. Output control operation switch (12a)
and a temperature control operation switch (12b).

The opposite side is an operation switch that functions as an output setting section or a temperature setting section.

FIG. 2 shows an example of the electric circuit of the present invention, in which 20 is a general commercial AC power supply, 20 is the power supply (a first power supply circuit for shaping the waveform into an appropriate waveform, and 20 is the power supply circuit). (A power transformer that has two or more types of secondary windings that can appropriately step down the 2G voltage; circuit, which is a third power supply circuit that receives the output of the second secondary winding.

(6) is a temperature sensing element, such as a thermistor, whose resistance value changes based on the detected temperature, and the output from the third power supply circuit (24) is used to convert the detected temperature into voltage using the change in resistance value. Connect the resistor (251 and the temperature sensing element (6) so as to divide it, and connect the dividing point (between the voltage and frequency) to the F conversion circuit (26).Then, the V-F conversion circuit 06) is It is connected to the F-V conversion circuit (c) via an insulating signal transmission means (5) such as a transformer or photocoupler.

The wire is a temperature control circuit that sends out a signal to perform a heating operation based on a set temperature set by an operation switch (13). (to) is a drive circuit that functions as a signal amplification section for operating the inverter circuit (C31), which is a high-frequency generation circuit that receives a signal from the temperature control circuit and performs high-frequency oscillation, and Gυ is a drive circuit ((4)
) to perform high-frequency oscillation in response to signals from
The heating output of the heating coil (to) is adjusted by adjusting the conduction period of a. (To) is the heating coil (To)
This is a load that is heated by induction.

The configuration of the present invention is as described above, and its operation will be explained below.

First, by turning on the power switch 00, the power transformer (22) is energized and the third power circuit (24) outputs the power.We will now explain the case of pot cooking. Temperature sensing element installed at the tip (6)
Since the resistance value changes depending on the temperature of the load 0ω detected by the sensor, that is, the temperature of the ingredients in the pot, the voltage at point A also changes based on the detected temperature. This voltage signal is transmitted to the temperature adjustment circuit (2!1) through the -F conversion circuit 06) - signal transmission means (2'?) - p-v conversion circuit (21?l), and then to the temperature adjustment circuit c29.
A comparison is made with a signal based on the set temperature set by the operation switch (13), and the conduction period of the switching transistor t is determined based on the result. This conduction period determines the heating output of the heating coil (to), and induction heating of the load (3) is performed.When heating continues and the temperature sensing element (6) detects a temperature higher than the set temperature, the temperature is adjusted. Since the circuit - sends a signal to stop the oscillation of the inverter circuit C31), the oscillation of the inverter circuit C31) stops and heating stops.

Next, we will discuss the case where the load C35+ is an iron plate used for grilling, etc. In this case, the temperature of the iron plate will be directly detected by the temperature sensing element (6) installed in the temperature sensor (the temperature sensor). In addition, when making tempura, the temperature of the oil will be detected as the temperature of load 051 using the temperature sensing element (6).In this way, the temperature of three loads C will be detected. The object whose temperature is detected by the temperature sensing element (6) provided in the temperature sensing probe (hereinafter referred to as the temperature sensing element 6) differs depending on the method of cooking and the type of object to be heated.

Now, as the signal transmission means (5), I mentioned a transformer, a photocoupler, etc., but it does not matter if it is structurally insulated but connected in terms of electrical signals. . Therefore, the temperature sensing probe (7) extending outward from the cooker body (1) is loaded with G! 5) When attempting to detect temperature by directly inserting the probe into the probe, there is no risk of electric shock even if the user touches the probe.

Furthermore, since the temperature of the load (351) is directly detected, the ability to follow rapid temperature changes of the load G51 is improved, the detection accuracy is also improved, and the accuracy of temperature control is increased.

(G) Effects of the Invention The present invention is as described above, and since a temperature sensing element is provided at the tip of the temperature sensing probe that can be directly inserted into the load and the temperature of the load can be directly detected, high accuracy is achieved based on accurate temperature detection. Temperature control becomes possible and the ability to follow rapid temperature changes in the load is improved.

Furthermore, since the temperature-sensitive glove and the strong electric circuit inside the cooker are insulated, the user will not be electrocuted by touching the temperature-sensitive probe, making it extremely safe.

[Brief explanation of drawings]

Each figure shows an embodiment of the present invention, with FIG. 1 being a perspective view of the appearance of the cooker, and FIG. 2 being a main circuit diagram. (6)...Temperature sensing element, (Force...Temperature probe,
(131...Temperature setting section (operation switch), (Foundation)
...Signal transmission means, wire...Temperature control circuit, 01)
...Inverter circuit, C321...Switching element, (c)...Heating coil.

Claims (1)

[Claims] 1. In an induction heating cooker equipped with a heating coil that inductively heats a load by generating a high-frequency alternating magnetic field by supplying high-frequency alternating current, a set temperature is specified for temperature control operation, and the set temperature is sent as an electric signal. a temperature setting unit that directly detects the temperature of a load and converts the detected temperature into an electrical signal; a signal transmission means that is electrically insulated and transmits a signal from the temperature sensing element; Induction heating characterized by comprising: a temperature adjustment circuit that receives both a signal from the transmission means and a signal from the temperature setting section and sends out a signal that adjusts the heating output of the heating coil based on the state of both. Cooker temperature control device.