JPH0817735B2 - rice cooker - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rice cooker using induction heating,
In particular, the amount of electric power is continuously changed according to the amount of cooked rice to cook rice.

Conventional technology A conventional rice cooker uses a sheathed heater as a heat source, and this sheathed heater is automatically turned on / off by ON / OFF control for a fixed time (for example, a 16-second cycle) by a triac according to the amount of cooked rice. You are in control.

Problems to be Solved by the Invention In such a conventional configuration, only electric power can be automatically controlled by ON-OFF control, and since the sheathed heater has preheating, responsiveness is slow and rapid temperature change of the pot is not possible. Have difficulty. In addition, there is a temperature difference in the pan between when the sheath heater is on and when it is off, and the temperature rise of the pan becomes gradual.Therefore, the temperature detection variation becomes large at the timing of detecting the temperature of the pan, resulting in subtle temperature and power consumption. It was difficult to control and I couldn't always cook delicious rice.

In addition, I couldn't cook delicious rice if I adjusted the amount of water.

The present invention solves such a problem, and quickly sets the optimum amount of electric power and heating time for any amount of cooked rice,
The first purpose is to always cook delicious rice.

The second purpose is to quickly set the optimum amount of electric power and heating time for any amount of rice and water, and always cook delicious rice even if the amount of water is wrong.

Means for Solving the Problems A first means for achieving the first object is a heating coil for induction heating a container, an inverter circuit for supplying a high frequency current to the heating coil, and an inverter circuit for heating the heating coil. The rice cooker includes a control circuit that controls a high-frequency current supplied to the coil, a rice cooker that detects the amount of cooked rice in the container, and a temperature detector that detects the temperature of the container. The control circuit continuously adjusts the amount of high-frequency current supplied to the heating coil by the inverter circuit in accordance with the output signal of the cooking device so that the optimum amount of electric power and heating time for cooking rice at that time are obtained. It is a thing.

The second means for achieving the above-mentioned second object is provided with water amount detecting means for detecting the amount of water in the container, and outputs the output signals of the water amount detecting means, the cooked rice amount detector and the temperature detector. Accordingly, the control circuit continuously adjusts the amount of high-frequency current supplied by the inverter circuit to the heating coil so that the optimum amount of electric power and heating time for cooking rice at that time are obtained.

Action In the rice cooker of the present invention, rice and water are put in a container, an inverter circuit supplies a high-frequency current to a heating coil, and when rice cooking is started, in the pre-cooking step of allowing the rice to absorb moisture sufficiently,
The control circuit changes the oscillation frequency of the inverter circuit according to the amount of rice cooked in the container and its temperature, or the amount of rice cooked, the amount of water and the temperature, to set the optimum amount of power and heating time for cooking rice at that time. Then let the rice absorb the water enough. Next, in the cooking process, the maximum power is used to boil all at once. Then, in the steaming step, the control circuit changes the oscillation frequency of the inverter circuit in accordance with the amount and temperature of cooked rice in the container, or the amount of cooked rice, the amount of water and the temperature thereof, and the optimum power for cooking rice at that time. Steam the rice by setting the amount and heating time.

In this way, the control circuit changes the heating time and the oscillation frequency of the inverter circuit according to the amount of cooked rice and its temperature, or according to the amount of cooked rice, the amount of water, and the temperature so that the power is appropriate in each cooking process. The amount of electric power is adjusted accordingly.

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

FIG. 1 is an electric circuit diagram of a jar rice cooker using induction heating showing a first embodiment of the present invention for realizing the first object. Reference numeral 12 is a commercial power source to which an inverter circuit 8 is connected. . The inverter circuit 8 includes a rectifier 14 connected to a commercial power supply 12, a choke coil 16 and a smoothing capacitor 17 connected in series with a capacitor 15 connected to the output terminal of the rectifier 14,
It is composed of a resonance capacitor 18 connected to the smoothing capacitor 17, and a switching transistor 19 containing a diode connected in antiparallel.

The capacitor 15 and the choke coil 16 form a filter circuit.

The heating coils 4 and 5 are connected in parallel with the resonance capacitor 18 to form a resonance circuit. The control circuit 13
The ON-OFF operation of the switching transistor 19 is controlled. Reference numeral 20 denotes a weight detector, which is a kind of a rice cooking amount detector inside the container 3 provided at the bottom of the container 3, and is, for example, a weight sensor or the like, and a control circuit according to the amount of rice cooking inside the container 3.
Output to 13.

Reference numeral 21 is a temperature detector provided at the bottom of the container 3, which is, for example, a thermistor, and the output of the temperature detector 21 is sent to the control circuit 13.

In FIG. 2, reference numeral 1 is a jar rice cooker main body, which is provided inside with a storage portion 2 for storing a pot 3 which is a container for storing rice and water, and the upper portion of the main body 1 is openably and closably covered by an upper lid 9. The pan 3 can be taken out by opening and closing the upper lid 9. Numerals 4 and 5 are heating coils for inductively heating the pot 3, which are placed on the support base 6, and a plurality of ferrite cores 7 for absorbing the wetting magnetic flux are radially provided below the support base 6. . 10 is a load detection device that moves up and down and mechanically detects whether or not the pan 3 is a proper container for cooking rice.
It is provided on the bottom surface of the pan 3, and if the pan 3 is unsuitable for cooking rice, it outputs a signal to the control unit 13 that the pan is unsuitable. The control unit 13 controls the oscillation of the inverter circuit unit 8 provided at the bottom of the main body 1 that supplies the high-frequency current to the heating coils 4 and 5, and controls the operation display unit 11 provided at the top of the main body 1.

In the above configuration, the control circuit 13 changes the conduction time of the switching transistor 19 according to the output signals of the weight detector 20 and the temperature detector 21, that is, according to the amount of cooked rice in the container 13 and its temperature, and heats the switching transistor 19. The amount of high frequency power supplied to the coils 4 and 5 is automatically controlled, and the amount of power for cooking rice and the heating time at that time are appropriately set.

That is, since the control circuit 13 continuously changes the oscillation frequency of the inverter circuit 8 according to the amount of cooked rice in the container 3 to automatically adjust the input power, any amount of cooked rice in the container 3 is always delicious. It can be cooked.

When the amount of power is adjusted, the input frequency is automatically adjusted by continuously changing the oscillation frequency of the inverter circuit 8. Therefore, the voltage drops by several volts when heating is turned on as in the conventional ON-OFF control. However, due to the voltage fluctuation during this ON-OFF,
For example, it is possible to eliminate the drawbacks such as the beating caused by the fluctuation of the input power and the fluctuation of the rotation speed of the fan motor.

Next, FIG. 3 shows a second embodiment for realizing the second object. In the figure, a water amount detecting means 32 for detecting the amount of water in the container 3 is provided at the bottom of the container 3, and the water amount detecting means 32 detects the amount of water in the container 3 and controls it according to the water amount. Output to circuit 13.

In the above configuration, the control circuit 13 is responsive to the output signals of the weight detector 20, the temperature detector 21, and the water amount detecting means 32.
That is, the heating time and the conduction time of the switching transistor 19 are changed according to the amounts of rice and water in the container 3 and the temperature thereof, and the high frequency power amount supplied to the heating coils 4 and 5 is automatically controlled to generate power. Set the amount and properly.

That is, depending on the amount of rice and water in the container 3 and its temperature, the control circuit 13 increases the heating time or increases the input power, for example, if the amount of water is larger than the amount of rice. Since the input time is automatically adjusted by continuously changing the heating time and the oscillation frequency of the inverter circuit 8, no matter what amount of rice and water in the container 3, that is, the amount of water added, will always be delicious. You can cook.

Although the weight detector 20, the temperature detector 21, and the water amount detecting means 32 are provided at the bottom of the container 3 respectively, the present invention is not limited to this, and is provided at any position where each function can be achieved. May be.

Further, the weight detector is used as a means for detecting the amount of cooked rice, but the invention is not limited to this, and the amount of cooked rice may be determined by the temperature rise rate of the cooked rice. If

EFFECTS OF THE INVENTION As is clear from the description of the above embodiments, the present invention has the following effects.

(1) Since the electric energy is continuously set optimally according to the amount of cooked rice, the temperature rise curve of the pan becomes smooth, and the detection accuracy of the temperature detector that detects the temperature of the pan can be greatly improved.

(2) The amount of cooked rice and its temperature are detected, and the heating time and power consumption are optimally set according to the amount of cooked rice and its temperature, so it is possible to control the heating time and power consumption delicately, and any amount of cooked rice will always be delicious. You can cook rice.

(3) Since the amount of electric power is continuously changed, it is possible to prevent the fluctuation of the amount of electric power due to the drop of the input voltage during heating and the whining of the wind noise due to the change in the rotation speed of the fan motor.

(4) The amount of rice and water and its temperature are detected individually,
Since the heating time and electric energy are optimally set according to the amount of rice and water and its temperature, the heating time and electric energy can be delicately controlled and delicious rice can be cooked always with any amount of rice and water.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a jar rice cooker showing a first embodiment of the present invention, FIG. 2 is a sectional view of the same body, and FIG. 3 is a jar rice cooker showing a second embodiment of the present invention. It is an electric circuit diagram. 3 ... Container, 4,5 ... Heating coil, 8 ... Inverter circuit, 13 ... Control circuit, 20 ... Weight detector, 21 ... Temperature detector, 32 ... Water amount detecting means.

Claims (2)

[Claims] 1. A heating coil for induction heating a container, an inverter circuit for supplying a high frequency current to the heating coil, a control circuit for controlling the high frequency current supplied by the inverter circuit to the heating coil, and A rice cooking amount detector that detects the amount of cooked rice and a temperature detector that detects the temperature of the container are provided, and the control circuit is the inverter circuit according to the output signals of the rice cooking amount detector and the temperature detector. The rice cooker controlled by continuously adjusting the amount of high frequency current supplied to the heating coil to obtain the optimum amount of power and optimum heating time in each rice cooking process. 2. A heating coil for induction heating a container, an inverter circuit for supplying a high frequency current to the heating coil, a control circuit for controlling the high frequency current supplied by the inverter circuit to the heating coil, and The rice cooking amount detector for detecting the amount of cooked rice, the temperature detector for detecting the temperature of the container, and the water amount detecting means for detecting the amount of water in the container, the control circuit, the rice cooking amount detector, the In accordance with the output signals of the temperature detector and the water amount detecting means, the amount of high frequency current supplied to the heating coil of the inverter circuit is continuously adjusted to obtain the optimum power amount and optimum heating time for each rice cooking process. A controlled rice cooker.