JPH0445949B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device for an electric hot plate used in general households.

Conventional technology Conventionally, in the control device of an electric hot plate, a temperature sensor detects the temperature at the bottom of the plate, and when the temperature is raised to a set temperature, the heater is continuously energized until the set temperature is reached, and when the set temperature is reached. The configuration was such that the power to the heater was stopped.

Problems to be Solved by the Invention However, in the temperature control method described above, the temperature continues to rise for a while even after the power supply to the heater is stopped, so the plate temperature rises to a temperature higher than the set temperature. The higher the set temperature, the more likely the fluorine on the plate surface will be thermally degraded due to the temperature overshoot mentioned above. The temperature must be lower by the temperature difference between
Even though there are foods that must be cooked at the highest temperature possible, there is a problem in that the maximum temperature that can be set must be lowered.

In view of the above-mentioned problems, an object of the present invention is to eliminate the excessive temperature overshoot that occurs when the plate temperature rises, improve the durability of the bare surface, and increase the maximum settable temperature.

Means for Solving the Problems To achieve this object, the electric hot plate control device of the present invention includes a temperature detection means for detecting the temperature of the plate, and a temperature control means for controlling the temperature at a plurality of temperature points. , a control temperature setting means for setting the temperature controlled by the temperature control means, and a heater power reduction means for reducing the heater power.

Effect With this configuration, the temperature controlled by the temperature control means is first set by the control temperature setting means, the temperature control operation is started, and the temperature detection means is controlled until the plate temperature reaches the control temperature. When it is detected that the temperature has reached a certain temperature lower than the temperature, the heater power reduction means reduces the heater power at a reduction rate according to the control temperature set by the control temperature setting means.

As a result, the overshoot of the plate temperature with respect to the control temperature can be suppressed to just the right amount, compared to when electricity is continued until the control temperature is reached.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram showing the configuration of an embodiment of the present invention, in which 1 is an AC power supply, power switch 2,
A series circuit of relay contact 4a and heater 3 is connected. The relay contact 4a is driven to open and close by a relay coil 4b, and the relay contact 4a and the relay coil 4b constitute a relay. Outputs from a temperature detection means 5 for detecting the plate temperature and a control temperature setting means 6 for selecting and setting a desired plate temperature by a user using a control temperature selection switch 7 are input to a temperature control means 8. The control temperature setting means 6 is for selecting and setting three types of control temperatures, θ ₂ , θ ₃ and θ ₄ shown in FIG.

The temperature control means 8 adjusts the temperature at the control temperature set by the control temperature setting means 6. That is, the output of the temperature detection means 5 and the control temperature are compared, and the heater power is adjusted by controlling the energization rate of the relay 4. The operation starts when the control temperature selection switch 7 is pressed. When the temperature control means starts operating and the temperature detection means 5 detects that the temperature has reached a temperature lower than the control temperature set at that time, the heater power reduction means 9 reduces the relay energization rate controlled by the temperature control means 8. is changed and reduced at a reduction rate according to the control temperature, and the power of the heater 3 is reduced.

The operation of the electric hot plate control device constructed as described above will be explained below with reference to the flowchart shown in FIG.

First, in step 101, the control temperature selection switch 6 is operated to select a desired control temperature. Here, if the control temperature is selected at θ ₄ shown in FIG. 2, θ ₃ becomes the starting point of the heater power reduction means,
At the same time, temperature control operation is started, and step 102
If the temperature θ at the start point is θ≧ _θ4 , the plate temperature is higher than the control temperature, so step 1
Proceed to step 03, set the relay on/off cycle to 16 seconds, set the relay energization rate to 0/16, that is, leave the relay off, and repeat until θ<θ _{4 .}
If so, proceed to step 104 and set the relay energization rate.
16/16, and in step 105, if the plate temperature has never reached the control temperature and the power has not been reduced by the heater power reduction means, the process proceeds to the next step 106; otherwise, If so, return to step 102. When proceeding to step 106, it is determined whether the plate temperature θ is a temperature at which the heater power reduction means is started. If θ<θ ₃ , the process returns to step 102; if θ≧θ ₃ , the process proceeds to the next step 107. and proceed. In step 107, the relay energization rate is determined based on the set control temperature _Qs , and if _Qs = _Q4 , the process advances to step 108, and _Qs = _Q3 .
If Q s =Q 2 , the process proceeds to step 109 , and if Q _s =Q ₂ , the process proceeds to step 110 .

In this example, the explanation is given as Q _s = Q ₄ , so
In this case, the process advances to step 108, and the relay energization rate becomes 12/16 from FIG. Next step 111
Then, the plate temperature Q is the control temperature Q _s , that is,
It is checked whether Q ₄ has been reached, and if it has not, proceed to step 107 and repeat until Q≧Q ₄ . When the plate temperature Q reaches _Q4 , the process returns to step 102. At this time, since the plate temperature Q is higher than the control temperature _Q4 , the process proceeds to step 103, where the relay energization rate becomes 0/16 from FIG. Power supply is stopped. If Q<Q ₄ in step 102, the process proceeds to steps 104 and 105, but since the set temperature has been reached in step 105, the process does not proceed to step 106, and the process proceeds to step 102.
and then step 102 to step 1.
05 is repeated.

Similarly, when the control temperature θ _S is set to θ ₃ , θ ₂ becomes the start temperature of the heater power reduction operation, the relay energization rate is reduced by 10/16, and the control temperature θ _S is set to θ ₂ .
If θ ₁ is the starting temperature of heater power reduction operation,
The relay energization rate is 8/16, reducing the amount of current to the heater. By performing these operations described above, overshoot when the plate temperature rises is suppressed, and the energization to the heater is reduced at the optimum energization rate for each control temperature, so it is possible to perform control without excess or deficiency. be. Note that the relay energization rate shown in FIG. 4 is changed depending on the combination of the plate temperature θ and the control temperature θ _S.

Effects of the Invention As described above, by providing a heater power reduction means, the present invention can prevent excessive overshoot when the plate temperature rises, and improve the durability of the fluororesin coded on the plate surface. This improves performance and also makes it possible to raise the maximum temperature that can be set. In addition, since the energization to the heater is reduced at the energization rate that is optimal for each control temperature, overshoot can be suppressed without excess or deficiency, and cooking can be performed without failure when cooking at each set temperature.

[Brief explanation of drawings]

Fig. 1 is a circuit block diagram of a control device for an electric hot plate according to an embodiment of the present invention, Fig. 2 is a chart of plate temperature rise characteristics during temperature control, and Fig. 3 is a flowchart of a microcomputer used in the control device. FIG. 4 is a diagram showing relay energization rate settings. 3... Heater, 4... Relay, 5... Temperature detection means, 6... Control temperature setting means, 8... Temperature control means, 9... Heater power reduction means.

Claims (1)

[Claims] 1. A plate having a heater, a temperature detection means for detecting the temperature of the plate, a temperature control means for controlling the temperature at a plurality of temperature points, and a control temperature setting means for setting the temperature to be controlled by the temperature control means. A heater power reduction means that reduces the heater power from a temperature that is a certain temperature lower than the control temperature until the plate temperature reaches the control temperature when the temperature rises from the start of the temperature control operation until the plate temperature reaches the control temperature. A control device for an electric hot plate, characterized in that the power reduction rate performed by the heater power reduction means is a power reduction rate according to the control temperature set by the control temperature setting means.