JPH09219278A - Cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooker with no noise and quick and stable startup at switch-ON by changing the timing of outputting an ON signal to an switch in accordance with a current value for a input current to a halogen heater. SOLUTION: A cooker has a halogen heater 2 connected to a power supply 1 via a switch 3 and a controller 4 provided to ON/OFF-control the switch 3. A current sensor 6 detects an input current to the halogen heater 2 so that the timing of outputting an ON signal to the switch 3 can be changed in accordance with a current value detected by the current sensor 6. It is desirable that a current value detected by the current sensor 6 is a value for a current flow equivalent to one waveform of power voltage when the switch 3 is turned ON.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker using a halogen heater.

[0002]

2. Description of the Related Art Since a halogen heater has a very large resistance change due to temperature, a large current (8 to 10 times higher than a normal current) flows when the cold halogen heater rushes in (at the start of energization). Therefore, when the halogen heater is used, it is necessary to turn it on and off with an element that can withstand a large current at the time of this rush. Also, as a method of avoiding a large current at the time of inrush, a method of gradually increasing the energization time by phase control or a resistor connected in series to the halogen heater so that it can be intermittently connected, and that resistor is connected at the time of inrush There is a method of lowering the voltage applied to the halogen heater at the time of rushing by disconnecting the connection of the resistor on the way. Furthermore, actual fair 6-3
As disclosed in Japanese Patent No. 0123, a method of intermittently turning on / off a triac by a timer to suppress an inrush current has also been proposed.

[0003]

However, an element capable of withstanding a large current at the time of inrush is large and costly. The phase control method causes noise. The method of lowering the voltage at the time of inrush requires another resistor and a circuit switching mechanism, which is high in cost, complicated in structure, and large in size. Further, the method of intermittently turning on and off the triac by a timer to suppress the inrush current requires the same time for rising even when the heater is hot or cold. The present invention has been made in view of the above problems, and an object of the present invention is to provide a heating cooker that does not generate noise and has a fast start-up and a stable start at the time of entry.

[0004]

In order to solve the above-mentioned problems, the present invention relates to a heating cooker provided with a control unit for connecting a halogen heater to a power source through a switch and controlling the switch on / off. A current sensor for detecting an input current to the halogen heater is provided, and an output timing of an ON signal to the switch is changed according to a current value detected by the current sensor.

According to the present invention, since the output time of the ON signal to the switch is changed according to the current value of the input current to the halogen heater, noise is not generated unlike the phase control and a switching circuit is not necessary. . In the present invention,
Regardless of the state of the halogen heater, the rush current flowing at that time is detected by the current sensor, and the time of the next ON signal to the switch changes according to the current value. Therefore, when the halogen heater is cold, such as when cooking is started, it is possible to slowly start up without burdening the switch with the inrush current. Also, like when cooking again soon after the previous cooking is over,
If the halogen heater is still hot, it will rise faster.

The current value detected by the current sensor is preferably a current value that flows when the switch is turned on by one waveform of the power supply voltage. By passing the current for one waveform in this way, it is possible to avoid the burden on the switch due to the large current at the time of inrush, but to accelerate the heat generation of the halogen heater by the current and reduce the inrush current. You can

The change of the ON signal to the switch is performed by turning OFF the switch and then outputting the ON signal for a predetermined time selected according to the current value detected by the current sensor. You may do it. Here, when the current value detected by the current sensor is large, the time to turn off the switch is lengthened, and when the current value is small, the time to turn off the switch is shortened, so that the temperature of the halogen heater and the power supply voltage are reduced. Regardless of the state, the halogen heater can be started up stably and efficiently.

The predetermined time selected according to the current value detected by the current sensor may be indicated by the number of pulses generated by the pulse generator that detects the zero cross of the power supply voltage and generates a pulse. According to this, since the time for turning off the switch is indicated by the number of pulses, there is an advantage that it is easy to control the timing of the ON signal to the switch.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a circuit configuration of the heating cooker of the present invention. A halogen heater 2 is connected to the AC power source 1 via a triac 3 which is a switch. The triac 3 is controlled by an on / off signal from the control device 4. To the AC power source 1, a ZVP generator 5 that generates a pulse when a zero cross of the AC waveform is detected is connected. Further, the connection circuit from the AC power supply 1 to the halogen heater 2 is provided with a current sensor 6 that generates a voltage proportional to the current flowing through the circuit. The pulse signal from the ZVP generator 5 and the voltage signal from the current sensor 6 are input to the control device 4, and the control device 4 controls the on / off signal to the triac 3 based on these signals. Has become.

Next, the operation of the heating cooker having the above-described structure will be described with reference to the flowchart of FIG. 2. First, in step 101, whether a heater-on signal is input by pressing a start switch (not shown) of the heating cooker. If the heater ON signal is input, it is determined in step 102 whether the ZVP signal is input. If the ZVP signal is input, the gate signal is output to the triac 3 by one waveform of the voltage waveform of the power supply 1 in step 103. This turns on the triac 3 and the halogen heater 2
Current flows through. The rush current at this time is detected by the current sensor 6, and the current sensor 6 outputs the voltage V corresponding to the rush current. Therefore, in step 104, the output voltage V of the current sensor 6 is fetched, and in step 105, the number of pulses N is determined according to the output voltage V from the table shown in Table 1.
Is selected.

[0011]

[Table 1] Current level at inrush The number of pulses before turning on next (output voltage of current sensor) (output pulse of ZVP generator) 4V or more 10 pulses 3 to 4V 7 pulses 2.5 to 3V 4 pulses 2. 2 to 2.5V 2 pulse 2 to 2.2V 1 pulse 2V or less 0

If the selected pulse number N is 0, normal control is performed in step 111, but the pulse number N is generally not 0 at the start of heating. Therefore, in step 107, the pulse count number n is set to 0, Then, the process proceeds to next step 108. In step 108, it is determined whether or not the pulse count number n matches the selected pulse number N. If they do not match, it is determined in step 109 whether or not the ZVP signal is input. If there is a ZVP signal input, step 110
Then, n = n + 1 is set and the process returns to step 108, and step 10 is repeated until the count number n reaches the selected pulse number N.
Repeat 8 to 110. If the count number n matches the selected pulse number N, the process returns to step 103, the gate signal for one waveform is output again, and so on until the selected pulse number N becomes 0, and so on. Repeat step.

Waveforms A, B, C, and D in FIG. 3 are the power supply voltage waveform and Z, respectively, in the heating cooker of the above embodiment.
Examples of VP pulse, gate output, and current waveform (output voltage of current sensor) are shown. In this example, the halogen heater 2
Is applied with a power supply voltage having a waveform shown by A, and the ZVP generator 5 outputs a pulse of B corresponding to the zero cross of this voltage waveform. When the start switch of the heating cooker is pressed, the control device 4 outputs a gate output for one waveform of the voltage waveform to the triac 3 in synchronization with the ZVP pulse, as shown in C. Then, the inrush current at this time is detected by the output voltage V of the current sensor 6 as indicated by D, and the pulse number N = 4 is selected from the above table 1 according to the output voltage V. As a result, the control device 4 skips 4 pulses and then outputs the gate output for one waveform to the triac 3 again. Then, after skipping 2 pulses, 1
Output the gate output for the waveform to the TRIAC 3,
Then, one pulse is skipped and the gate output is continuously output. In this way, the halogen heater 2 is activated so that the triac 3 is not burdened.

Although the triac 3 is used as the switch in the above embodiment, other elements such as a solid state relay may be used. Further, it goes without saying that the pulse numbers shown in Table 1 are merely examples and can be changed according to the type and capacity of the halogen heater 2 used. further,
In the above embodiment, the output time of the ON signal to the triac 3 is controlled by counting the number of pulses, but it may be controlled by the time measured by the timer.

[0015]

As is apparent from the above description, since the time point of the ON signal to the switch is changed according to the current value, noise is not generated unlike the phase control.
Further, a stable rising can be realized regardless of the temperature of the halogen heater, the power supply voltage, and the like. Further, since there is no need for an element capable of withstanding a large current at the time of inrush and a voltage switching circuit is also unnecessary, there is an effect that the structure is inexpensive and the structure is simple.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a heating cooker according to the present invention.

FIG. 2 is a flowchart showing the operation of the heating cooker of the present invention.

FIG. 3 is various waveform charts showing the operation of the heating cooker of the present invention.

[Explanation of symbols]

1 ... AC power supply, 2 ... Halogen heater, 3 ... Triac, 4 ... Controller, 5 ... ZVP generator, 6 ... Current sensor.

Claims (4)

[Claims] 1. A heating cooker in which a halogen heater is connected to a power supply via a switch and a control unit for controlling on / off of the switch is provided with a current sensor for detecting an input current to the halogen heater, A heating cooker characterized in that an output time of an ON signal to the switch is changed according to a current value detected by the current sensor. 2. The cooking device according to claim 1, wherein the current value detected by the current sensor is a current value that flows when the switch is turned on by one waveform of the power supply voltage. 3. The change of the ON signal to the switch is to output the ON signal after turning OFF the switch for a predetermined time selected according to the current value detected by the current sensor. The method according to claim 1, wherein
Or the heating cooker according to any one of 2). 4. The predetermined time selected according to the current value detected by the current sensor is represented by the number of pulses generated by a pulse generator that detects a zero cross of the power supply voltage and generates a pulse. The cooking device according to claim 3, characterized in that.