JP2502626B2 - Heater control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a controller for a hot air heater.

2. Description of the Related Art Conventionally, the proportional solenoid valve that controls the output of a warm air heater adjusts the amount of fuel in proportion to the value of the current that flows to the coil as its basic characteristic, so the control circuit changes the current linearly. In addition, a positive-phase amplification type constant current circuit that can stably flow is generally used.

Problems to be Solved by the Invention Generally, in the above-mentioned conventional control circuit, since the current that can flow in the transistor is linearly changed to control the current to the proportional solenoid valve, the power loss of the transistor increases and a large radiator is required. I had to attach it to the transistor. As a result, the cost of the control circuit is increased and the running cost is increased due to unnecessary power loss.

In view of the above problems, the present invention provides a cheap and economical control circuit for a warm air heater that can linearly adjust the current flowing through the proportional solenoid valve without requiring a large radiator and has no power loss. The purpose is to

Means for Solving the Problems In order to achieve the above object, the control circuit of the hot air heater according to the present invention responds to the difference between the set room temperature set by the room temperature setting means and the room temperature detected by the room temperature detecting means. Heating output determining means for determining the output signal, frequency determining means for converting the signal from the heating output determining means into a predetermined frequency, and correcting the signal from the frequency determining means according to voltage fluctuations and temperature characteristics of the circuit. Frequency correction means, frequency output means for outputting a signal from the week number correction means, pulse width conversion means for converting a pulse width of the signal from the frequency output means, and pulse driving with a signal from the pulse width conversion means. A proportional solenoid valve drive circuit, a gas type heating output signal correction circuit for correcting the output signal from the heating output determination means for each gas type, and a gas type heating output signal correction circuit A deviation amplifying circuit for determining a deviation between a signal and a heating output detection signal obtained by detecting a current flowing through the proportional solenoid valve is provided.

Action The present invention has the above-described configuration, determines the heating output according to the difference between the set room temperature and the room temperature, converts the heating output into a frequency, and this frequency is the current heating that detects the energizing current of the proportional solenoid valve. The proportional solenoid valve drive circuit is pulse-driven through the pulse width conversion circuit, which outputs at the frequency corrected by the output observation signal. By driving the proportional solenoid valve drive circuit with a pulse in the above configuration, the power loss of the transistor for turning on / off the current flowing through the proportional solenoid valve is reduced, and the radiator can be eliminated.

Example An example of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a microcomputer, which is a CPU, a ROM,
It is a so-called one-chip microcomputer having a RAM and an input / output unit, and has a heating output determining means (2), a frequency determining means (3), a frequency correcting means (4), a frequency output means (5), and at the same time, operation of the appliance. It controls the overall control.
A room temperature detecting means 6 converts the resistance value of the thermistor into a voltage, which is then A / D converted and enters the heating output determining means 2 of the microcomputer 1. 7 is the same as the room temperature setting means A /
The heating output determining means 2 of the microcomputer 1 is entered by means such as a D converter. The heating output determining means 2 determines the heating output according to the difference between the room temperature data from the room temperature detecting means 6 and the room temperature setting temperature data from the room temperature setting means 7, based on FIG. That is, if the difference between the room temperature and the set room temperature is -t ° C or less, the heating output is set to MAX, if the difference is + t ° C or more, the heating output is set to MIN, and the heating output is proportionally adjusted between -t ° C and + t ° C. To do. The frequency determining means 3 determines the signal from the heating output determining means 2 based on FIG. 3 also stored in the ROM. That is, when the heating output is MIN, the frequency is Fmin (Hz), and the heating output and the frequency are in a proportional relationship. The frequency correcting means 4 corrects the signal of the frequency determining means 3 by absorbing the voltage fluctuation and the atmospheric temperature fluctuation by the signal from the deviation amplifying circuit 22 described later. That is, as shown in FIG. 4, if the value of the signal of the deviation amplifying circuit 22 is 0, the correction frequency is 0, and if it is -b, the correction frequency is -f (Hz), and this value is added to the signal of the frequency determining means 3. And is output by the frequency output means 5. Va in FIG. 5 shows this output waveform. 8 is a pulse width conversion means, a capacitor 9,
It is composed of resistors 10, 11, 12 and a comparator 13. The signal passing through the capacitor 9 becomes a waveform of Vb shown in FIG. 5 by the differentiating circuit composed of the capacitor 9 and the resistor 10. Comparator
13 is a value V obtained by dividing the Vb and the voltage Vdd by the resistors 11 and 12.
The output waveform Vd shown in FIG. 5 is output by comparing with c. 14 is a proportional solenoid valve drive circuit, transistor 15, resistance 16,17, transistor 18, proportional solenoid valve 19, electrolytic capacitor 20, resistance
Consists of 21. The transistor 15 repeats the on / off operation by the signal Vd from the pulse waveform converting means 8.
As a result, a current flows through the base resistor 17 of the transistor 18, and the transistor 18 also operates on / off. The on time and off time at this time are T shown in the waveform of Vd in FIG.
Based on on and Toff. When the transistor 18 is turned on, current flows through the proportional solenoid valve 19, the electrolytic capacitor 20, and the resistor 21, and when the transistor 18 is turned off, the electrolytic capacitor 20
Current flows from the proportional solenoid valve 19 to the closed circuit of the resistor 21. As a result, the current Ip continuously flows through the proportional solenoid valve 19. FIG. 5 shows the waveform of the current Ip flowing through the proportional solenoid valve 19 pulse-driven by the output waveform Vd of the pulse width conversion means 8. twenty two
Is a deviation amplifier circuit and comprises resistors 23, 24, 25, 26 and an operational amplifier 27. Operational amplifier 27 which detected a voltage proportional to the current flowing through the proportional solenoid valve 19 when the transistor 18 was turned on by the resistor 23
, And the signal from the heating output determining means 2 is input to the gas type heating output signal correction circuit 30 via the D / A converter 29 and corrected to a heating output signal corresponding to the fuel gas type. Connected to the non-inverting input terminal of the operational amplifier 27. The deviation of the heating output detection signal based on the gas type heating output signal is output to the output of the operational amplifier, and the frequency correction means via the A / D converter 28. I am typing in 4.

According to the configuration of the above embodiment, the transistor 18 repeats the on / off operation by the signal Vd of the pulse width conversion means 8 to drive the proportional solenoid valve 19, so that the power loss of the transistor 18 is small and a radiator is not necessary. Therefore, the control circuit can be downsized, and an inexpensive and economical control circuit for the hot air heater can be realized.

As described above, according to the present invention, the heating output corresponding to the difference between the room temperature and the set room temperature is converted into a frequency, and the proportional solenoid valve drive circuit 14 is pulse-driven after the pulse width conversion, and further proportional. The current value flowing through the solenoid valve is fed back to the microcomputer to correct the frequency, enabling stable control against voltage fluctuations and atmospheric temperature fluctuations.
Therefore, since the pulse-driven transistor has less power loss, less heat is generated and a radiator is unnecessary,
The control circuit can be miniaturized, and an inexpensive and economical control circuit for the heating machine can be realized without power loss.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a graph showing the principle of determining the heating output, and FIG. 3 is a graph showing the principle of determining the frequency from the heating output. FIG. 4 is a graph showing the principle of determining the correction value of the frequency, and FIG. 5 is a waveform diagram of the main part of the circuit shown in FIG. 2 ... Heating output determining means, 3 ... Frequency determining means, 4 ...
… Frequency correction means, 8 …… pulse width conversion means, 14 …… proportional solenoid valve drive circuit, 18 …… transistor, 19 …… proportional solenoid valve, 30 …… gas type heating output signal correction circuit.

Claims (1)

(57) [Claims] 1. A proportional solenoid valve for linearly adjusting fuel to a burner, a heat exchanger, a room temperature detecting means for detecting an indoor temperature, a room temperature setting means for setting an indoor temperature, and the room temperature setting means. Heating output determining means for determining an output signal according to the difference between the set room temperature and the room temperature detected by the room temperature detecting means, a frequency determining means for converting the signal from the heating output determining means into a predetermined frequency, and the frequency. Frequency correction means for correcting the signal from the determination means in accordance with voltage fluctuations and temperature characteristics of the circuit, frequency output means for outputting the signal from the frequency correction means, and pulse width conversion for the signal from the frequency output means. A pulse width converting means, a proportional solenoid valve drive circuit pulse-driven by a signal from the pulse width converting means, and a gas type for correcting the output signal from the heating output determining means to the gas type. The present invention is characterized by including a tuft output signal correction circuit and a deviation amplification circuit for obtaining a deviation between a signal from the gas type heating output signal correction circuit and a heating output detection signal obtained by detecting a current flowing through the proportional solenoid valve. Control device for the heater.