KR200296244Y1 - D.c automatic temperature controller for electronic mat - Google Patents

Abstract

The present invention relates to a temperature controller for an electronic mat, and an object of the present invention is to provide an apparatus using an AC power source as an input, rectifying the same, and converting the same into a direct current.

To this end, the 8-bit microcontroller 30 is used to receive a voltage according to the value of the variable resistor 40 for temperature control of the temperature controller through the analog-to-digital conversion input terminal, and then the value and the temperature detection sensor 20 In controlling the trigger of the thyristors by comparing with the voltage corresponding to the measured temperature, a device for generating a trigger signal in synchronization with the point of time when the current becomes zero is configured.

This configuration suppresses the discomfort of stimulating the human body's hearing from the generation of harmonics and the low frequency force caused by the rapid change of the current flowing through the heating wire.

Description

DC thermostat for electronic mat {D.C AUTOMATIC TEMPERATURE CONTROLLER FOR ELECTRONIC MAT}

Conventionally, the method of controlling the phase of the triac by changing the variable resistance value is mainly used to set the temperature controller for controlling the heater, but in this method, the current cut by the phase angle from the current of the normal SIN wave flows in the heating wire in both directions. The generation of harmonics due to rapid current changes and low hum of 60 Hz stimulated the human body's hearing, causing discomfort to the user.

Therefore, the present invention has been devised to solve the above problems, using the 8-bit microcontroller 30 to convert the voltage according to the value of the variable resistor 40 for temperature control of the temperature controller through the analog-to-digital conversion input terminal. In order to generate the trigger of the thyristors by comparing the value with the voltage corresponding to the temperature measured by the temperature detection sensor 20, the synchronization at the time when the current becomes zero to suppress the sudden change of the current at this time By generating a trigger signal and turning on the thyristor, the current of the heating wire is gradually increased from zero. In addition, since the thyristor is automatically turned off in the vicinity of zero where the current in the opposite direction is about to flow due to the characteristics of the thyristor, it is to provide a device in which the current is not suddenly changed.

1 is a circuit diagram of a DC thermostat according to the present invention.

2 is a waveform of current flowing in a heating wire.

<Explanation of symbols for main parts of drawing>

10: heating wire

20: temperature detection sensor

30: microcontroller

40: variable resistance for temperature control

50: bridge diode

60: thyristor

Features of the DC thermostat according to the present invention for achieving the above object, using an inexpensive 8-bit microcontroller 30 having an 8-bit multi-channel analog-to-digital converter and 13 input and output pins The voltage V1 according to the value of the temperature control variable resistor 40 is read through the analog input terminal of the microcontroller 30, and the voltage V2 which changes according to the temperature of the electronic mat from the temperature detection sensor 20 is read by the microcontroller 30. After reading through the analog input terminal, the trigger signal is generated by comparing V1 and V2. The start point of the final trigger signal is determined by constructing an AND circuit with the point of the AC input voltage near zero. Since the load is a heating wire, most of the impedance is a resistance, and thus the zero point of the current is detected by the magnitude of the voltage because the phase of the voltage and current is almost identical. Therefore, in the actual circuit, three voltages, a temperature control voltage V1, a temperature detection voltage V2, and a zero voltage detection voltage V3, are used as signals for generating a trigger signal.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 and 2 are a circuit diagram and a current waveform diagram of a temperature controller according to the present invention, as shown in the input voltage for detecting the variable resistor 40 and the temperature detection sensor 20 and zero bolt as shown in the microcontroller Analog-to-digital conversion is connected to the analog input terminal. The final thyristor's trigger output is synchronized to zero volts to suppress sudden changes in current.

As described above, by turning on the thyristors for controlling the current flowing to the heater using the microcontroller 30 at zero volts and turning them off at the zero volts, a sudden current change can be suppressed, especially in one direction rather than in both directions. It is to have the effect of suppressing the occurrence of low frequency force by flowing current.

Claims (1)

In controlling the electric current flowing in the heating wire of the electronic mat, after converting the AC input voltage to direct current, the temperature controller characterized in that to trigger the thyristors at zero volts using a microcontroller.