JP2003134863A - Thermal power generation controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a motor, without using a large output type thermal power generation unit. SOLUTION: A voltage of a power generated by a thermocouple 35 is stepped up by a first step-up circuit 36, in which a voltage is induced in its coil L2 by the on/offs of its switching device FET1. The generated power is accumulated temporarily in electrolytic capacitors C4 and C7, after a state where the output voltage of the first step-up circuit 36 is not lower than 2.2 V continues for 30 seconds and, further, after a lapse of two minutes, since the start of the current application and then a motor 38 is driven to start.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric generator control device for supplying electric power from a thermoelectric generator to a motor.

[0002]

2. Description of the Related Art Conventionally, an electromotive force of a thermocouple (thermoelectric generator) heated by combustion heat of a burner is boosted by a booster circuit, and an actuator (load) such as a motor is driven by the boosted output voltage.
There is known a thermoelectric power generation control device that drives a motor. As an example of application of such a thermoelectric generation control device to an infrared stove,
In addition to radiant heat from a red-hot plate type gas burner, an infrared stove with a fan that heats by hot air from a blower fan driven by thermoelectric power generation is known. The motor of the blower fan does not require much electric power during rotation, but needs a large amount of electric power at startup.

[0003]

However, if an attempt is made to cover the electric power required for starting the motor with the electric power generated by the thermocouple, a thermocouple which generates a large electromotive force is required, which leads to an increase in the cost of the thermocouple. Was there. An object of the present invention is to solve the above problems and to drive a motor without using a high-power type thermoelectric generator.

[0004]

A thermoelectric power generation control apparatus according to claim 1 of the present invention which solves the above-mentioned problems, has a thermoelectric power generation section for generating electric power by combustion heat of a burner, and boosts electric power generated by the thermoelectric power generation section. Booster circuit, a motor driven by the boosted power, a power storage unit that stores the boosted power, and the booster in the power storage unit from a time when the burner is ignited or equivalent timing accompanying the ignition to a predetermined time. A motor drive control unit that stores electric power, supplies the stored electric power to the motor as electric power for starting the motor after the lapse of the predetermined time, and directly supplies the boosted electric power to the motor after starting the motor. The main point is that.

According to a second aspect of the present invention, there is provided a thermoelectric power generation control device, a thermoelectric power generation section for generating electric power by combustion heat of a burner, a booster circuit for boosting the electric power generated by the thermoelectric power generation section, and the boosted voltage. A motor driven by electric power, a power storage unit that stores the boosted power, and when the output voltage of the booster circuit exceeds a predetermined voltage, the power stored in the power storage unit is supplied to the motor as motor starting power. However, the gist of the present invention is to include a motor drive control unit that directly supplies the boosted power to the motor after the motor is started.

A thermoelectric power generation control device according to a third aspect of the present invention is the thermoelectric power generation control device according to the second aspect,
The gist of the motor drive control unit is to start the motor when the output voltage of the booster circuit is equal to or higher than a predetermined voltage for a predetermined time.

In the thermoelectric power generation control device according to claim 1 of the present invention having the above-mentioned configuration, the thermoelectric power generation unit generates electric power by the combustion heat of the burner, and a predetermined time has elapsed from the time of ignition, or an equivalent power supply associated with ignition. The boosted electric power is stored in the power storage unit until a predetermined time has elapsed from the timing, and after the predetermined time has elapsed, the motor is started by the power stored in the power storage unit. Since the motor does not require a large amount of electric power once it starts to be driven, after starting, the motor continues to be driven directly by the boosted power from the booster circuit without being supplied with power from the power storage unit.

According to a second aspect of the present invention, in the thermoelectric power generation control device, the thermoelectric power generation section generates electric power due to the combustion heat of the burner and the output voltage of the booster circuit is kept at a predetermined value or higher in the power storage section. After storing the electric power, the stored electric power is used for starting the motor. Since the motor does not require a large amount of electric power when it is started, the motor is continuously driven by the boosted electric power from the booster circuit.

According to a third aspect of the present invention, in the thermoelectric power generation control device, the thermoelectric power generation section generates electric power, and the output voltage of the booster circuit remains in the power storage section for a predetermined time until the output voltage is equal to or higher than the predetermined voltage. After storing the electric power, the stored electric power is used to start the motor. If the output voltage of the booster circuit temporarily becomes equal to or higher than the predetermined voltage, it is not considered that the required power has been stored in the power storage unit, so that the power for starting the motor can be stored more reliably.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the thermoelectric generation control device of the present invention will be described below.

A thermoelectric power generation controller as an embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view of an infrared stove 1 with a fan (hereinafter, simply referred to as stove 1). The stove 1 is provided with a red-heat plate type burner 4 facing the radiation opening 2 in a main body case 3 having a radiation opening 2 provided on the front surface.

The burner 4 is provided with a burner body 6 which forms a mixing chamber of fuel gas and primary air, and a ceramic combustion plate 7 which is provided in the burner body 6 and which is provided with a large number of flame holes. This is a primary air type burner, in which the fuel gas sucked through a suction hole (not shown) and the primary air are mixed well in the burner body 6, and the mixture is burned.
From the flame holes of and the surface is burnt on the combustion plate 7.

Further, the burner body 6 is the upper burner body 13
And the lower burner main body 15 are divided and formed in upper and lower two stages. Further, the combustion plates 7 are provided in the upper burner main body 13 and the lower burner main body 15 in pairs, respectively.
Two types of heat power switching can be performed: strong heat power setting that burns on the entire surface and low heat power setting that burns only on two surfaces provided on the lower burner body 15.

A fan 9 is provided at the bottom of the main body case 3 to discharge the combustion gas of the burner 4 from a warm air outlet 8 provided at the lower front portion of the main body case 3. Behind the burner 4, there is a combustion gas inlet 10 near the top of the burner 4, and the fan 9 has a mixture of combustion gas and room temperature air (warm air).
A hot air intake passage 11 for guiding the air is provided. The fan 9 and the hot air outlet 8 are communicated with each other by the hot air delivery passage 12.

Further, the combustion gas suction port 10 is provided above the rear surface of the instrument.
A room temperature air suction port 16 is opened at a position substantially opposite to and communicates with the warm air intake passage 11. Therefore, when the fan 9 is driven, the combustion gas is sucked from the combustion gas suction port 10,
The room air is sucked from the room temperature air suction port 16 and mixed in the warm air intake passage 11 and the warm air delivery passage 12, and the mixture of the combustion gas and the external air is heated as an appropriate warm air outlet 8.
Sent from.

Further, a plurality of guard bars 14 are provided at the radiation opening 2 and the warm air outlet 8 so that the user's hand cannot enter the instrument body. Further, on the front surface of the combustion surface 5 of the burner 4, a series type thermocouple 35 arranged in front and rear two rows.
Are provided so as to face each other, and the electric power obtained by the thermocouple 35 is used as the power source of the motor 38 of the fan 9. Also,
On the left and right sides of the fan 9, there are provided a thermoelectric generation control device 30 for controlling electric power generation by the thermocouple 35 and a dry battery 32 (broken line in FIG. 2).

A DC brushless motor is used as the motor 38 of the fan 9. This is because the brush motor is a mechanical contact type and is easily worn and has poor durability. The brushless motor 38 has an IC 38b, which is an integrated circuit for controlling the rotation of the motor 38, inside, and is configured to switch the transistors of the IC in a short cycle.

As shown in FIG. 1, the thermoelectric generator control device 30 mainly includes a controller 31, a dry battery 32, an ignition switch 33, a power supply circuit 34, a thermocouple 35, a first booster circuit 36, and a second booster. It is composed of a circuit 37, a load drive circuit 39, etc. First, the configuration and operation of these will be described.
The symbol CN in the figure indicates a connector.

The controller 31 is mainly composed of a microcomputer, and performs thermoelectric power generation control and motor drive control. The operating voltage of the controller 31 is 3V and the withstand voltage is 5.
It is 5V. The ignition switch 33 is a connection switch between the dry battery 32 and the power supply circuit 34, and is turned on in conjunction with the ignition operation of the ignition lever. The thermocouple 35 is provided in the vicinity of the burner 4 of the stove 1 and is heated by a flame to generate electric power with an electromotive force of about 1 V. This electric power is used as a power source for the controller 31 and the motor 38.

The first booster circuit 36 is a DC / DC converter that boosts the electromotive force generated in the thermocouple 35, and its power (voltage is VCC2) is supplied to the winding 38a of the motor 38 to drive the motor 38. . This first booster circuit 36
Is a FET1 (switching element), F, which is turned on / off by a pulse signal from the output port c of the controller 31.
From the coil L2 that induces a voltage by turning on / off the ET1, the electrolytic capacitor C3 that reduces the impedance when discharging the coil L2, the electrolytic capacitor C4 that stores electric charges, the power source after boosting (electrolytic capacitor C4 and electrolytic capacitor C7 described later) A Schottky barrier diode D3 that prevents current from flowing to the booster circuit 36 side is provided.

The Schottky barrier diode D
In No. 3, the voltage drop is as small as 0.2 to 0.3 V, the power consumption in this diode is suppressed to the minimum, and the generated power can be effectively supplied to the load.

In the first step-up circuit 36 having such a structure, it is considered that the electromotive force of the thermocouple 35 has reached a predetermined value 3 seconds after the ignition operation (the ignition switch 33 is turned on).
The controller 31 transmits a pulse signal whose frequency and duty ratio are adjusted from the output port c to the FET1, and turns on and off the FET1 by the pulse signal, thereby inducing a voltage in the coil L2 and input voltage from the thermocouple 35. (1V) is boosted to store electric energy. The frequency and duty ratio adjustment control will be described in detail later.

When the FET1 is on, the electromotive force of the thermocouple 35 causes a current to flow through the coil L2. When the FET1 is turned off, the voltage rises due to the property of the coil L2 in order to keep the current flowing, and the current passes through the connection point A between the first booster circuit 36 and the power supply circuit 34 to drive the second booster circuit 37 and the load. Flow to circuit 39. Then, this current is applied to the load drive circuit 3
9 is used as a power supply to the winding 38a of the motor 38 (the applied voltage is VCC2). This boosted electric power is used by the motor 38 and the pseudo load 40 of the load drive circuit 39 described later.
Output voltage V of the first booster circuit 36
CC2 has an average of 2.6V. The controller 31
The voltage is detected from the input port b.

The second booster circuit 37 further adds the output voltage (2.6 V) boosted by the first booster circuit 36 to a predetermined voltage (3).
It is a DC / DC converter that boosts voltage to V), and includes an IC 37a that is an integrated circuit dedicated to the second booster circuit 37 that incorporates a FET that serves as a switching element, a coil L1, an electrolytic capacitor C2, and a diode D2. The second booster circuit 37 turns on and off the FET of the IC 37a by a pulse signal, thereby inducing a voltage in the coil L1 and inputting a voltage from the power supply circuit 34 and the first booster circuit 36, which will be described later, to VDD (3V). Up to IC 38b of motor 38 (required operation voltage is 3V), controller 31
The power is supplied to the power supply port d, etc.

As described above, the power source of the controller 31 is
VDD without using VCC2 (output of second booster circuit 37)
Is used. This is because when VCC2 is used, the applied voltage becomes unstable under the influence of the load (necessary power) of the winding 38a of the motor 38. Also,
This is because the voltage required to drive the first booster circuit 36 cannot be obtained from VCC2 in the initial stage.

The voltage VDD of the IC 37a of the second booster circuit 37 is equal to the voltage IC3 of the controller 31 and the motor 38.
Light load of 8b (0.3mW at 3V, 0.1mA)
Since it is only connected, the change in boost is small and stable even when it is turned on and off. On the other hand, the output voltage VCC2 of the first booster circuit 36 is the heavy load of the motor 38 (usually 2.
Since it is connected to 416 mW at 6 V and 160 mA, the change in boost is large and unstable each time it is turned on and off. As described above, since the applied voltage is divided between the motor 38 and the controller 31, an unstable voltage is not applied to the controller 31 that controls the control, and the control can be normally performed.

A power MOSFET is used for the FET1 of the first booster circuit 36 and a large amount of current can be passed therethrough. However, the IC 37a of the second booster circuit 37 cannot pass a larger amount of current than the FET1. It is not suitable for driving a large load such as the winding 38a of the motor 38, and is used in a booster device for supplying electric power to a component having a small load such as the controller 31 and the IC 38b of the motor 38.

When the load that consumes the power from the first booster circuit 36 is large, the output voltage VC of the first booster circuit 36 is large.
Since C2 is small, the voltage Vb of the input port b is also low, and there is no fear of failure of the controller 31. On the other hand, when the load is small, the output voltage VCC of the first booster circuit 36
2 becomes about 10V, so the voltage Vb of the input port b
Is too high and the controller 31 may fail, but the failure can be prevented because the input voltage is divided in half by the resistors R5 and R6 (each resistance value is equal).

In order to prevent a failure due to overvoltage of the controller 31, the input port b (voltage detector) has a diode D4 for limiting the voltage Vb applied to the input port b.
Is provided and connected to VDD through the diode D4. Since the voltage drop of the diode D4 is as small as about 0.7V, even if the electromotive force boosted by the first booster circuit 36 becomes very large, the maximum value of the voltage Vb of the input port b becomes “VDD (3V ) + 0.7V ", that is, 3.7
There is no risk that the controller 31 will be damaged by the V.

With the electromotive force generated by the thermocouple 35, the voltage required to start the motor 38 cannot be obtained, so it is necessary to boost the electromotive force. For that purpose, the first booster circuit 36 is operated. Power must be supplied to the controller 31. As its power source, dry cell 32 (voltage V
CC1 uses 1.5V).

When the thermocouple 35 starts to generate an electromotive force of a predetermined value or more after the ignition for a while, the electric power for the controller 31 is covered by the electromotive force, so that the dry battery 32 is used.
The power supply from the controller to the controller 31 can be stopped. The power supply circuit 34 is a circuit that cuts off the power supply and switches to the power supply from the thermocouple 35, and is controlled by the controller 31.

This power supply circuit 34 includes an electrolytic capacitor C1, an electrolytic capacitor C1 and a transistor which are connected to the bases of a transistor Q1 and a transistor Q1 which open and close a supply path of a dry battery power supply to a second booster circuit 37 through a limiting resistor R2. Limiting resistor R1 provided between the emitter of Q1
And a diode D1, a Zener diode ZD1 connected to the output port a of the controller 31 and a collector of the digital transistor DT1 and the transistor Q1 connected between the limiting resistor R2 and the electrolytic capacitor C1.

R1 is a limiting resistor for preventing overcurrent during discharging, and R2 is a limiting resistor for preventing overcurrent during charging.
The Zener diode ZD1 is connected to the controller 31
The applied voltage to the device does not exceed its withstand voltage of 5.5V. Further, the diode D1 is provided for discharging the electric charge accumulated in the electrolytic capacitor C1 when the ignition switch 33 is turned off, and thus the electrolytic capacitor C1 can be used as a timer (described later) also at the next ignition.

In the power supply circuit 34, when the ignition switch 33 is turned on by the ignition operation, the current from the dry battery 32 flows from the emitter of the transistor Q1 to the base, and the transistor Q1 is turned on. This current flows to the limiting resistor R2 and the electrolytic capacitor C1. With the ON operation of the transistor Q1, a current flows from the emitter to the collector and the second booster circuit 37 and is boosted from 1.5V to 3V (VD
D), and this output voltage VDD is used as the power supply of the controller 31.

About 10 seconds after the ignition switch 33 is turned on, the electric charge of the electrolytic capacitor C1 is accumulated, and the current stops flowing through the electrolytic capacitor C1.
Turns off. Here, the electrolytic capacitor C1 functions as a timer.

Next, the load drive circuit 39 will be described. The load driving circuit 39 includes a pseudo load 40 including resistors R7 and R8, a digital transistor DT2 that controls energization of the pseudo load 40 by a signal from the output port e of the controller 31, and a signal from the output port f of the controller 31. FET2 for driving and controlling the motor 38 by
The diode D5 for returning when the motor 38 is stopped, the ceramic capacitor C8, the electrolytic capacitor C7, and the FET2
And a resistor R10 for turning off.

The pseudo load 40 keeps boosted electric power until it is time to start the motor 38, that is, until the electromotive force from the thermocouple 35 is stabilized and it is considered that electric charges are accumulated in the electrolytic capacitors C4 and C7. The motor 38 is energized instead of being energized, and is de-energized while the motor 38 is being driven. The pseudo load 40 is slightly lighter than the load resistance when the motor 38 rotates.

Next, the adjustment control of the boosting efficiency in the first boosting circuit 36 performed by the controller 31 will be described with reference to the flowcharts of FIGS. As described above, the voltage of the control signal from the controller 31 to the FET 1 and the on-resistance of the booster circuit (the resistance between the drain and the source of the FET 1) are in inverse proportion to each other, and the higher the voltage, the smaller the on-resistance. Energy loss during boosting is reduced and boosting efficiency is increased. Therefore, here, the voltage is controlled to be increased.

First, the ignition switch 3 is interlocked with the ignition operation.
When 3 is turned on, control of boosting efficiency is started. As shown in FIG. 3, as a default setting, the switching frequency is set to 6 kHz, the duty ratio (ratio of ON time in one cycle) is set to 70% (S1), and the frequency change code indicating increase / decrease when adjusting the frequency is set. Is set to +, and the duty ratio change sign indicating the increase / decrease when adjusting the duty ratio is also set to + (S
2). It waits until 3 seconds have passed since the ignition switch 33 was turned on (S3), and after 3 seconds passed, the frequency adjustment processing (S
4) The duty ratio adjusting process (S14) is repeated so that the output voltage reaches the peak.

FIG. 4 shows frequency adjustment control. First,
The current VCC2 detected at the input port b is stored as V1 (S5). Since VCC2 is divided in half by resistors R5 and R6, for example, 1.5V at input port b
Is detected, the VCC2 at that time is 3.0V. Then, when the frequency change code is +, 0.25 kHz is added to the frequency (here, 6 kHz), and when the frequency change code is −, 0.25 kHz is subtracted from the frequency (S6). It waits until 3 seconds have passed since the frequency was changed (S7), and after 3 seconds, it is considered that the voltage has become stable and the current VCC2 is detected as V2 at the input port b (S2).
8).

Voltage V1 before frequency change and voltage V after change
2 is compared (S9), and it is determined whether the voltage V2 is 3.5 V or less (S10, S13). This judgment value is 3.5V
The reason is that the upper limit of the output voltage VDD of the second booster circuit 37 is set to about 3 V, and as a result, the voltage V2 is increased.
Does not extremely exceed the input voltage of the second step-up circuit 37 over 3.4 V (diode D2 voltage drop 0.4 V + VDD). If the voltage V2 exceeds the voltage V1 (S9: YE
S), it can be seen that the voltage is boosted by changing the frequency, that is, the boosting efficiency is increased. At this time, the voltage V2 is 3.5V
If it exceeds (S10: NO), in order to prevent the failure of the controller 31 (withstand voltage 5.5 V) due to excessive boosting, the frequency change sign is set to the opposite sign (S1).
2) Make sure to step down when returning to step 6 next time. That is, + → − and − → +.

On the other hand, when the voltage V2 is 3.5 V or less (S10: YES), the frequency change code is kept the same as this time in order to maximize the output voltage (S10: YES).
11) When the process returns to step 6 next time, the voltage is further increased. Then, the process shifts to a subroutine for adjusting the duty ratio.

In step 9, the voltage V2 is changed to the voltage V1.
If it is below (S9: NO), it can be seen that the voltage is lowered by changing the frequency, that is, the boosting efficiency is lowered. At this time, if the voltage V2 exceeds 3.5V (S13: N
O), the frequency change code is kept the same as this time in order to further reduce the voltage so that the controller 31 (withstand voltage of 5.5 V) does not break down (S11). On the other hand, the voltage V2 is 3.5V
If the following is true (S13: YES), the frequency change sign is set to a sign opposite to this time in order to boost the output voltage so as to maximize the output voltage (S12). Then, the process shifts to a subroutine for adjusting the duty ratio.

FIG. 5 shows the duty ratio adjustment control.
First, the current voltage V1 is stored in the input port b (S1
5) When the duty ratio change sign is +, 2% is added to the duty ratio (here, 70%), and when the duty ratio change sign is −, 2% is subtracted from the duty ratio (S1
6). The control waits until 3 seconds have passed since the duty ratio was changed (S17), and after 3 seconds, the current voltage V2 is detected assuming that the voltage is stable (S18).

The voltage V1 before the duty ratio change and the voltage V2 after the change are compared (S19), and it is determined whether the voltage V2 is 3.5 V or less (S20, S23). If the voltage V2 exceeds the voltage V1 (S19: YES), it can be seen that the boosting efficiency has been increased by changing the duty ratio. On this occasion,
If the voltage V2 is 3.5 V or less (S20: YES),
To further boost the voltage, the duty ratio change code is kept the same as this time (S21). If the voltage V2 exceeds 3.5V (S20: NO), the duty ratio change code is opposite to this time in order to prevent further voltage increase. Sign (S22),
Return to the frequency adjustment subroutine.

In step 19, the voltage V2 is the voltage V
If it is 1 or less (S19: NO), it can be seen that the boosting efficiency is lowered by changing the duty ratio. At this time, if the voltage V2 is 3.5 V or less (S23: YES), the duty ratio change sign is set to the opposite sign to this time in order to boost the voltage (S22). On the other hand, if the voltage V2 exceeds 3.5 V (S23: NO), the duty ratio change code is kept the same as this time in order to further reduce the voltage so that the controller 31 (withstand voltage 5.5 V) does not fail. S2
1). Then, the process returns to the subroutine for adjusting the frequency.
As shown in FIG. 3, by alternately repeating the frequency adjustment (S4) and the duty ratio adjustment (S14), the output voltage approaches the maximum peak, and the boost efficiency is improved. Moreover, since the output voltage does not exceed 3.5 V, the controller 31 can be prevented from malfunctioning. For example, when the required power of the load is small, the load can be driven without forcibly increasing the boosting efficiency. On the other hand, when the required power of the load is large, it is necessary to increase the boosting efficiency, but the output voltage V of the first boosting circuit 36 is set so that the boosting efficiency is not so high that the controller 31 is damaged.
The upper limit value of CC2, 3.5V, is set.

Next, the control of the power supply circuit 34 will be described with reference to the flowchart of FIG. Controller 31
Turns on the digital transistor DT1 from the output port a before the timer by the electrolytic capacitor C1 ends (here, immediately after the ignition operation) (S31). As a result, a current flows through the dry battery 32 → the emitter of the transistor Q1 → the base → the digital transistor DT1 → the dry battery 32, keeping the transistor Q1 in the ON state regardless of the timer, and the controller by the dry battery 32 via the second booster circuit 37. The power supply to 31 is continued. At this time, the electric charge accumulated in the electrolytic capacitor C1 is discharged toward the digital transistor DT1 and disappears.

When the electromotive force of a predetermined value or more continues to be generated from the thermocouple 35, it becomes unnecessary to supply the electric power by the dry battery 32. Therefore, the controller 31 uses the resistor R
5, using the resistor R6, the voltage VCC2 (=
2 Vb) is monitored (S32), and when it is detected that the voltage VCC2 is 2.0 V or more, which is higher than the voltage (1.8 V) of the new dry battery 32, the power from the thermocouple 35 is used instead of the dry battery 32. Assuming that it can be used as a power source for the controller 31, a signal for turning off the digital transistor DT1 is transmitted from the output port a (S3).
3). When the digital transistor DT1 is turned off, electric charge starts to be accumulated in the electrolytic capacitor C1 again, and when the electric charge is completely accumulated, the current does not flow in the transistor Q1 and the transistor Q1 is turned off. Is turned off. Therefore, thereafter, the electromotive force of the thermocouple 35 is boosted by the second booster circuit 37 and used as the power supply VDD of the controller 31.

Now, the detection of the voltage Vb at the input port b by the controller 31 will be described. The electromotive force of the thermocouple 35 before boosting can be detected by turning off the FET1 of the first boosting circuit 36 and the digital transistor DT1 of the second boosting circuit 37. The voltage boosted by the first booster circuit can be detected by turning off the digital transistor DT1 of the second booster circuit 37. Even if the digital transistor DT1 is not turned off, if the detected value exceeds the voltage 1.8 V of the new dry battery 32, the electromotive force can be detected as the voltage boosted by the first booster circuit 36. The voltage of the dry battery 32 can be detected by turning on the digital transistor DT1 of the second booster circuit 37.

In the controller 31, when the electromotive force of the thermocouple 35 supplies power through the second booster circuit 37, the voltage VCC2 at the input port b becomes 1.8 V or less of the new dry battery 32. Is detected (S34:
YES), digital transistor DT from output port a
A signal for turning on 1 is transmitted (S35), and the power supply circuit 34
Is operated to receive electric power from the dry battery 32 through the second booster circuit 37. Therefore, even if the electromotive force of the thermocouple 35 suddenly drops due to a gust of wind or the like, the electric power is supplied from the dry battery 32, so that the operation of the controller 31 does not stop.

In addition, when the voltage VCC2 at the input port b is 1.8 V or less for 5 minutes (S3
6: YES), the controller 31 determines that the burner 4 has disappeared, and transmits a signal for turning off the digital transistor DT1 from the output port a (S37).
The power supply circuit 34 is stopped to stop the power supply from the dry battery 32. At this time, since no electric power is supplied from the thermocouple 35, the controller 31 and the motor 38 are stopped. On the other hand, when power is supplied from the dry battery 32, the voltage VCC2 is 1.8 V or less in the middle of 1.8 V without continuing for 5 minutes.
If it exceeds (S36: NO), the process returns to step 32 and the voltage VCC2 is monitored again.

Next, the drive timing of the motor 38 will be described. The controller 31 is provided with two timers that determine the timing of driving the motor 38. One timer controls the output voltage V of the first booster circuit 36.
When it is detected that the state in which CC2 is 2.2 V or higher continues for 30 seconds (first condition), and the other timer detects that 2 minutes have elapsed since the ignition switch 33 was turned on (second condition). It is considered that the electromotive force of the thermocouple 35 is stable, and the drive of the motor 38 is started using this electromotive force.

However, since the motor 38 has a very heavy load at the time of starting, the rotation cannot be started only by directly increasing the electromotive force of the thermocouple 35. Therefore, the electric charge generated from the thermocouple 35 is applied to the electrolytic capacitor C4.
By temporarily storing at C7 and supplying power to the motor 38, the motor 38 can be rotated at once from the stopped state. The applied voltage at this time is about 3.5V. Even immediately after the motor 38 is started, the second booster circuit 37 consumes electric power in the diode D2, so that the output voltage thereof is about 3.2 V, and there is no fear of causing the controller 31 to malfunction.

The drive control of the motor 38 will be described with reference to the flowchart of FIG. Immediately after the ignition operation, the digital transistor DT2 is turned on (S41), and the boost voltage VCC2 from the thermocouple 35 is applied to the pseudo load 40,
Electric charges are stored in the electrolytic capacitors C4 and C7.

Then, the two timers in the controller 31 respectively output the output voltage VCC2 of the first booster circuit 36.
Of 2.2 V or higher for 30 seconds (first condition) is detected (S42: YES), and it is detected that 2 minutes have passed since the ignition switch 33 was turned on (second condition) ( S43: YES), it is considered that the electromotive force of the thermocouple 35 is stable and the electric charges are accumulated in the electrolytic capacitors C4 and C7.

Then, the digital transistor DT2 is turned off (S44), the energization of the pseudo load 40 is stopped, and the FET2 is turned on (S45).
8 energization is started. The power supply voltage of the motor 38 at the time of starting is about 3V.

Since the motor 38 that has started to rotate does not require a large amount of electric power thereafter, the voltage (2.6 V) obtained by boosting the electromotive force of the thermocouple 35 is stored even if a large amount of electric charge is not accumulated in the electrolytic capacitors C4 and C7. As it is, the motor 38 can be continuously driven.

When the output voltage VCC2 of the first booster circuit 36 becomes 2.0 V or less during the driving of the motor 38 (S
46: YES), because the necessary voltage cannot be obtained, FET
2 is turned off (S47), and the drive of the motor 38 is stopped. When the voltage VCC2 becomes 2.0 V or less while the motor 38 is being driven, the FET 2 is switched off and the motor 38
Stop energizing.

As described above, since the electric power is supplied to the motor 38 after being stored by the electrolytic capacitors C4 and C7, the motor 38 can be started even if the thermocouple 38 does not generate a large electric power. Therefore, it is not necessary to use a thermocouple that generates a large amount of power, and the manufacturing cost of the thermocouple can be kept low.

The second drive timing of the motor 38
Depending on the condition (two minutes have passed since the start of energization), the electromotive force of the thermocouple 35 waits until it stabilizes, so that it is possible to reliably store electric charges in the electrolytic capacitors C4 and C7.

The first drive timing of the motor 38
A sufficient output voltage can be obtained from the first booster circuit 36 under the condition (a state in which the output voltage of the first booster circuit 36 is 2.2 V or more continues for 30 seconds). The electromotive force shortage due to ignition failure of No. 4 can be determined, and the motor 38 can be driven after confirming that the thermocouple 35 is actually generating power. Moreover, in addition to the condition that the output voltage is equal to or higher than the predetermined value, the condition that the state is continued for the predetermined time is also required. Therefore, the output voltage of the first booster circuit 36 is temporarily 2.2 V or higher. Even if it becomes, the drive of the motor 38 is not started,
Wait until the required power is stored. As a result, the electric power for driving the motor can be stored more reliably.

Even during the motor drive control, the boosting efficiency adjustment control is simultaneously performed. While the pseudo load 40 is energized, the boosting efficiency is adjusted by adjusting the frequency and the duty ratio according to the pseudo load 40. Perform adjustment control. Even if the output voltage is not maximized by this boost efficiency adjustment control, if the motor 38 is energized in step 46, the boost efficiency is adjusted by adjusting the frequency and duty ratio in accordance with the motor 38 this time. Take control.

As described above, when the energization of the motor 38 is started, the boosting efficiency is adjusted to the motor load to some extent. Therefore, the voltage adjusted for the pseudo load 40 is applied to the motor 38 at the time of starting. It is possible to reliably start driving.

If the pseudo load is not provided, the electric power is not consumed by the pseudo load before the motor 38 is energized, so that the frequency or duty ratio adjusted to make the boosting efficiency the optimum value is the energization of the motor 38. There is a large difference between before and after energization, and the output voltage of the first booster circuit 36 also drops sharply. Therefore, immediately after the motor 38 is energized, the motor 38
The voltage applied to the motor is too low and the motor 38 stops. On the other hand, in the present embodiment, the pseudo load 40 having a load resistance substantially equal to that of the motor 38 is used, and the motor 3
8. Since the boosting efficiency is adjusted in advance before starting, such a problem does not occur.

By repeating the frequency adjustment and the duty ratio adjustment even after the motor 38 is started, the generated power can be stably supplied to the motor 38 at an appropriate voltage. Even if the load of the motor 38 fluctuates due to wind entering the motor 38 or the like, the boosting efficiency is adjusted by alternately controlling the frequency and the duty ratio according to the required power. These frequencies and duty ratios vary depending on component variations, ambient temperature, and load size.
The output voltage can be accurately controlled by repeatedly controlling the frequency and the duty ratio while feeding back the output voltage (S9 in FIG. 4 and S19 in FIG. 5).

Although the motor 38 generates high frequency noise, as a countermeasure against this high frequency noise, the first booster circuit 3 is used.
6 and the input port b, a ceramic capacitor C
5, C6 are provided.

An LED is connected to the controller 32 to inform the user of the exhaustion of the dry battery 32, and the voltage of the dry battery 32 is confirmed at the input port b before the thermocouple 35 generates electricity. If, the LED is turned on.

Next, the relationship between the boosting efficiency and the switching element will be described. The boosting efficiency is greatly affected by the characteristics of the switching element (FET1) of the first boosting circuit 36. Electric power W that can be extracted from the thermocouple 35
Is the open circuit voltage of the thermocouple 35, R is the internal resistance of the thermocouple 35, r is the resistance of the entire thermocouple circuit (including the motor 38) connected to the thermocouple 35, and flows through the thermocouple circuit. If the current is I, then W = I ² r and I = V / (R +
Substituting r), W = V ² r / (R + r) ² . When this formula is differentiated by r to obtain the maximum value, the electric power W that can be taken out from the thermocouple 35 becomes maximum when r = R.

For example, when a plurality of thermocouples are combined to generate electric power, the internal resistance R of the thermocouple 35 is as small as 0.5Ω. Therefore, in order to boost the electric power from this and take out a large electric power, r = It is necessary to approach R (that is, r = 0.5Ω), and it is necessary to suppress the impedance of the booster circuit to a small value. For that purpose, it is necessary to reduce the on-resistance of the element that performs switching (power MOSFET, that is, FET1), and it is necessary to increase the gate voltage (input voltage) of FET1 to some extent.

If the output power VCC2 boosted by the first booster circuit 36 is used as the power source of the controller 31, its voltage changes due to the load fluctuation. Therefore, once the boosted voltage becomes low, the switching element The ON characteristic is deteriorated, the boosting efficiency is further lowered, and the boosted voltage is lowered, resulting in a vicious circle. Therefore, in the present embodiment, the switching element that greatly affects the boosting efficiency is a booster circuit (second booster circuit 37) different from the booster circuit (first booster circuit 36) of the main load (motor 38). It uses a boosted power supply to stabilize the voltage.

In the thermoelectric generator control device 30 described above, the first booster circuit 36 boosts the electromotive force of the thermocouple 35. Therefore, by connecting a large number of thermocouples, the motor 38 is started without generating a high electromotive force. This makes it possible to reduce the manufacturing cost of the thermocouple.

Next, the boosting efficiency will be described. Motor 3
The voltage required for the winding 38a of No. 8 is 2.6V and does not need to be the same voltage (3V) as the controller 31 and the IC 38b. For example, if you want to boost from 1V to 3V, if you want to boost from 1V to 3V at once,
There is a possibility that the boosting difference is too large to sufficiently boost the voltage to 3V. On the other hand, first, the first booster circuit 36
To 2.6V with a margin, the second booster circuit 27 surely boosts 2.6V to 3V. By thus boosting the voltage in two steps, it is possible to boost the voltage to a desired voltage without difficulty. Moreover, the larger the step-up difference, the lower the boosting efficiency due to the increase in energy loss. Therefore, the step-up circuit (second step-up circuit 37) for the applied voltage VDD (3V) of the IC 38b and the applied voltage VC of the winding 38a are reduced.
By dividing the boosting circuit for C2 (2.6V) (first boosting circuit 36), the boosting efficiency in the winding 38a becomes better than when the boosting target value is 3V. As a result, the generated power can be effectively used.

Further, in the thermoelectric generation control device 30, since the power supply source to the controller 31 is switched from the dry battery 32 to the thermocouple 35, the dry battery 32 is not wastefully consumed and the dry battery 32 is used for a long time. be able to.
Therefore, it is not necessary to replace the dry batteries frequently.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. is there. For example, in the adjustment control of the boosting efficiency, the frequency and the duty ratio may be adjusted once each instead of alternately and repeatedly adjusting the frequency and the duty ratio. Further, in order to increase the voltage applied to the motor at the time of starting, the load resistance of the pseudo load 40 may be made relatively small such as about half the load resistance of the motor 38. In addition, the driving timing of the motor 38 is set under the first condition "the state where the output voltage of the first booster circuit 36 is 2.2 V or more has continued for 30 seconds" and the second condition "two minutes have passed since the ignition switch 33 was turned on. In place of satisfying both of the "what has been done", the first condition may be satisfied, or the second condition may be satisfied.

Further, instead of waiting for a predetermined time (for example, 30 seconds) as in the first condition of the driving timing of the motor 38 (S42), the output of the first booster circuit 36 as shown in FIG. The condition may be that the voltage is equal to or higher than a predetermined voltage (for example, 2.2 V) (S142). The timing start condition of the second condition of the drive timing of the motor 38 may be set to the operation start time of the first booster circuit 36 instead of the ignition operation time. Good.

Further, the timing of switching the power supply source to the controller 31 from the power of the dry battery 32 to the power generated by the thermocouple 35 is not determined when the output voltage of the first booster circuit 36 reaches a predetermined voltage or more. The time may be when this state continues for a predetermined time. For example, as shown in FIG. 9, when VCC2 is determined to be 2 V or more in S32 of FIG. 6, when the state continues for 10 seconds as in S132, the power from the dry battery to the thermocouple to the controller 31 is increased. The supply source may be switched. In this case, the thermocouple 3 is not affected by the temporary increase in the electromotive force of the thermocouple 35.
Since the power is supplied from the dry battery 32 until the required operating power can be supplied to the controller 31 via the first step-up circuit 36 from 5, the operation of the controller 31 can be more reliably continued.

[0077]

As described in detail above, the first aspect of the present invention
According to the thermoelectric power generation control device of, since the electric power generated from the thermoelectric power generation unit is stored in the power storage unit for a predetermined time and the electric power is supplied to the motor at once, the motor can be operated without using the thermoelectric power generation unit that generates a large amount of electric power. Can be activated. Moreover, the manufacturing cost of the thermoelectric generator becomes low. Further, since the electric power generated by the thermoelectric generator is boosted by the booster circuit, even if the voltage generated by the thermoelectric generator is low, the boosted electric power can be directly supplied to the motor to stably drive the motor.

Further, according to the thermoelectric power generation control device of the second aspect of the present invention, in order to obtain the necessary electric power at the time of starting the motor, the power storage unit continues to operate until the output voltage of the booster circuit becomes a predetermined value or more. To store electric power and supply it to the motor at once,
The motor can be started without using the high-power type thermoelectric generator. Moreover, the manufacturing cost of the thermoelectric generator can be suppressed. Further, since the booster circuit boosts the power generated by the thermoelectric generator, even if the voltage of this power is low,
The motor can be stably driven by the boosted electric power. Moreover, the timing of discharging the motor is determined not by the elapsed time but by the magnitude of the output voltage of the booster circuit, so that the motor can be reliably charged and the motor can be started.

Further, according to the thermoelectric power generation control device of the third aspect of the present invention, since the necessary electric power is stored without being affected by the temporary increase in the output voltage of the booster circuit, the motor can be started more reliably. be able to.

[Brief description of drawings]

FIG. 1 is a thermoelectric generation control circuit diagram according to the present embodiment.

FIG. 2 is a schematic sectional view of an infrared stove with a fan according to the present embodiment.

FIG. 3 is a flowchart showing adjustment control of boosting efficiency in the first booster circuit according to the present embodiment.

FIG. 4 is a flowchart showing frequency adjustment control according to the present embodiment.

FIG. 5 is a flowchart showing a duty ratio adjustment control according to the present embodiment.

FIG. 6 is a flowchart showing control of the power supply circuit according to the present embodiment.

FIG. 7 is a flowchart showing motor drive control according to the present embodiment.

FIG. 8 is a flowchart showing motor drive control as a modified example.

FIG. 9 is a flowchart showing control of a power supply circuit as a modified example.

[Explanation of symbols]

1 ... Stove, 4 ... Burner, 9 ... Fan, 30 ... Thermoelectric power generation control device, 31 ... Controller, 32 ... Dry battery, 33 ...
Ignition switch, 34 ... Power supply circuit, 35 ... Thermocouple, 36 ...
First booster circuit, 37 ... Second booster circuit, 37a ... IC, 3
8 ... Motor, 38a ... Winding, 38b ... IC, 39 ... Pseudo load, FET1 ... Switching element, L2 ... Coil, C
1 to C4, C7 ... electrolytic capacitor, b ... input port, d
… Power port.

Continued front page    F-term (reference) 3L028 FB05 FC02                 5H001 AA01 AA08 AB03 AB11 AC04                       AE05                 5H570 AA30 BB02 BB09 CC04 CC07                       DD01 FF01 FF03 GG02 HA01                       HA02 HA08 HA15 HA20 HB02                       HB16 LL03

Claims (3)

[Claims] 1. A thermoelectric generator for generating electric power by combustion heat of a burner, a booster circuit for boosting the electric power generated by the thermoelectric generator, a motor driven by the boosted electric power, and the boosted electric power stored therein. The booster power is stored in the power storage unit and at the same time when the burner is ignited or at the same timing with ignition for a predetermined time, and after the predetermined time, the stored power is used as motor starting power for the motor. And a motor drive control unit for directly supplying the boosted power to the motor after the motor is started. 2. A thermoelectric generator that generates electric power by combustion heat of a burner, a booster circuit that boosts the electric power generated by the thermoelectric generator, a motor that is driven by the boosted electric power, and the boosted electric power that is stored. When the output voltage of the power storage unit and the booster circuit exceeds a predetermined voltage,
A thermoelectric generator comprising: a motor drive control unit that supplies the electric power stored in the power storage unit to the motor as electric power for starting the motor, and directly supplies the boosted electric power to the motor after the motor is started. Control device. 3. The thermoelectric generator according to claim 2, wherein the motor drive control unit starts the motor when a state in which the output voltage of the booster circuit is equal to or higher than a predetermined voltage continues for a predetermined time. Control device.