JPH1137600A - Power source for peltier element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a power source for a small-sized cooling/heating Peltier element of a low cost by providing a full wave rectifying device and a voltage converting means for stepwisely converting an output voltage of the device, thereby stepwisely changing the voltage. SOLUTION: The power source for a Peltier element comprises a full wave rectifying device 10 having a smoothing capacitor 11 for converting AC into DC and removing a ripple. In this case, an output voltage V1 of the device 10 can be stepwisely converted to any voltage of Vo (base voltage), Vo+a1, Vo+a2,..., or Vo+an by a voltage converting means having a DC-DC converter 21, constant voltage circuit 22 and coil 23. And, a second smoothing capacitor 31 is inserted parallel to an output side of the voltage converting means, and a changeover switch 35 for inverting polarity of the output voltage is interposed between an output side of the converting means and the Peltier element 81. And, a switching device 41 is inserted parallel to the converting means to output the output voltage of the device 10 directly to the element 81.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device for driving a Peltier element for cooling and heating.

[0002]

2. Description of the Related Art A cooling / heating device using a Peltier element that performs an exothermic reaction or an endothermic reaction in accordance with the direction of a current is known. And the power supply that drives the Peltier element
Particularly in the case of the cooling mode, it is important to keep the Joule heat generated from the Peltier element as low as possible. This is because the Joule heat generated in the Peltier element cancels the cooling effect and, if excessive, requires heat dissipation means such as a fan for the Peltier element.

As shown in FIG. 3, a simple drive power supply circuit 90 for a Peltier element 81 includes a full-wave rectifying device 91 for converting an AC voltage Vac to a DC voltage V1, and a changeover switch for switching the polarity of an output voltage (current). 92 is a basic component. In the figure, reference numeral 911 denotes a smoothing capacitor for removing a ripple, reference numeral 951 denotes an AC power supply, reference numeral 952 denotes a transformer, and reference numeral 93 denotes a switching element for turning on and off an input to the Peltier element 81.

[0004] It is important to remove the AC component from the output voltage V1 as much as possible by the smoothing capacitor 911.
A capacitor of about 4A is used. This is because the AC component of the voltage applied to the Peltier element 81 generates Joule heat in the Peltier element 81 without contributing to the cooling action. However, in the simple circuit 90, since there is no voltage adjusting means, the voltage fluctuation of the AC power supply 951 (about 9
0 to 110 V) directly appears as the drive voltage V1 of the Peltier element 81.

[0005] Therefore, when the voltage is low, the Peltier element 81 cannot exert a sufficient cooling effect. On the other hand, when the voltage is too high, Joule heat increases in proportion to the square of the voltage. Accordingly, the cooling effect is significantly reduced, and when the Joule heat is excessive, waste such as operating the fan for radiating heat to the Peltier element at a high speed increases. Further, when a voltage is applied to the Peltier element 81, the voltage cannot be increased stepwise, and the maximum voltage is applied to the element 81 immediately. Therefore, an electric shock is applied to the Peltier element, and there is a problem that the life of the Peltier element is shortened.

Therefore, as shown in FIG. 4, the input transformer is a transformer 955 with a tap, and the output voltage V1 or the temperature is detected by voltage detecting means or temperature detecting means (not shown). Is also used. Reference numerals 931 to 93 in FIG.
Reference numeral 3 denotes a switching element for selecting a tap of the transformer 955. In the case of the circuit 900, when a voltage is applied to the Peltier element 81, the voltage (tap) can be gradually increased from a low voltage (tap). And the life of the element can be increased.

[0007]

However, the power supply circuit 900 having the voltage adjustment function has the following problems. That is, the switching elements 931 to 933 need to have a large breaking capacity because they directly open and close the load current, and are expensive and relatively large. When the number of switching elements increases in proportion to the number of switchable voltage steps (the number of transformer taps), the cost and space increase, and especially when the number of output steps is increased to perform fine-grained control In this case, the size of the apparatus is increased and the cost is increased.

On the other hand, in the case of the simple power supply circuit 90,
As described above, in addition to its function being inferior, there is a problem that the capacity of the smoothing capacitor 911 becomes large and relatively large (this is the same in the circuit 900 with voltage adjustment). That is, since the output voltage of the full-wave rectifier circuit is the output of the final stage, much of the ripple must be removed, and the ripple that must be removed by the smoothing capacitor 911 is the peak value of the full-wave rectifier circuit. This is because the ripple is a ripple having a relatively low commercial frequency as a fundamental frequency.

For this reason, the space occupied by the capacitor is increased, which is one of the major factors that hinder the miniaturization of the device. The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a small and inexpensive Peltier element power supply device for cooling and heating which can change the output voltage stepwise.

[0010]

The present invention relates to a power supply device for driving a Peltier element for cooling and heating, comprising: a full-wave rectifying device having a smoothing capacitor for converting AC to DC and removing ripples; Output voltage V1 of rectifier device
By switching means Vo, Vo + a1, Vo + a2,.
.. A voltage conversion means that can be switched in a stepwise manner to either the voltage of Vo or an, a second smoothing capacitor inserted in parallel with an output side of the voltage conversion means, and an output side of the voltage conversion means. A switching switch inserted between the Peltier device and the output switch for inverting the polarity of the output voltage. A DC-DC converter having an output terminal and an output feedback terminal for conversion, and a constant voltage circuit A1, A2,... And a coil connected in series with the output terminal of the DC-DC converter. A power supply for the Peltier device, wherein a path is connected between an output feedback terminal of the DC-DC converter and an output terminal of the coil, and the second smoothing capacitor is connected to an output side of the coil. In the device.

What is particularly notable in the present invention is that the output of the voltage correction circuit is fed back to the output feedback terminal of the DC-DC converter of the voltage conversion means. The voltage correction circuit is configured such that on / off constant voltage circuits A1, A2,... An in which a Zener diode and a switching element are connected in parallel are connected in a single or a plurality of series.

Therefore, for example, the constant voltage circuits A1, A
An, for example, turns on the constant voltage circuit Ai (turns off the switching element to output the voltage Vi of the Zener diode), and turns off the other (turns on the switching element and turns off the voltage of the Zener diode). Output is killed), so that the voltage V
i is fed back to the DC-DC converter, and DC
The output of the DC converter is shifted from the base voltage Vo when the feedback value is zero to (Vo + Vi).

That is, a single or a plurality of constant voltage circuits A1,
A2... An Zener diode voltage is V1, V
2,..., Vn, and only one switching element of the constant voltage circuits A1, A2,.
The output voltage of the converter is Vo, Vo + V1, Vo + V
, Or Vo + Vn. As a result, by turning on one constant voltage circuit, the output voltage of the power supply
.. An can be switched to the number of stages obtained by adding 1 to the number n of the constant voltage circuits A1, A2,.

When a plurality of constant voltage circuits, for example, i constant voltage circuits are turned on, the voltages of the turned on constant voltage circuits are added to the base voltage Vo and output. For example, when the voltages of the Zener diodes of the constant voltage circuits A1, A2,... An are set to the same value Va as described in claim 3, the output voltage of the voltage conversion means becomes (V
o + i × Va). As a result, the output voltage is Vo ~
(Vo + n × Va) can be changed stepwise at equal intervals.

The constant voltage circuit used in the feedback circuit for changing the number of output voltages is composed of a control element having a small current, and a circuit element having a small current capacity (power) (a zener diode and a switching element). ), The size of the constant voltage circuit is small and inexpensive. Therefore, the constant voltage circuits A1, A2,.
The increase in cost and space is reduced by increasing the number of.

That is, in the case of the conventional power supply device 900 having a voltage adjusting function shown in FIG.
Elements 31 to 933 turn on and off the load current.
1 to 933 are expensive and large. As shown by a straight line 69 in FIG. 2, the cost and the size increase greatly in proportion to the number of voltage steps that can be switched. On the other hand, in the power supply device of the present invention, the straight line 61 in FIG.
As shown in (1), even if the number of steps of the output voltage that can be switched is increased, the increase in cost and space is reduced.

Further, the capacities and sizes of the first and second smoothing capacitors of the power supply circuit according to the present invention are significantly smaller than those of the conventional device. That is, in the device of the present invention, since the output of the full-wave rectifier circuit is the input voltage of the DC-DC converter and not the output of the final stage, there is no problem even if a large amount of ripple remains. May be much smaller than before.

Since the ripple included in the output of the DC-DC converter at the next stage is several volts or less, the peak value is small and the frequency is high, so the capacitance of the second smoothing capacitor is the first smoothing capacitor. It may be smaller than the capacitor for use. As described above, the space for the smoothing capacitor, which occupies a relatively large space in the conventional device, is reduced, which can contribute to downsizing of the device.

Therefore, according to the present invention, it is possible to efficiently and appropriately control the Peltier element by increasing the number of output voltages while maintaining low cost and small size. That is, by applying an appropriate output voltage to the Peltier element, efficient and good cooling / heating control characteristics can be obtained, and the voltage at the time of starting the Peltier element can be gradually increased. The electric shock can be reduced and the life of the element can be extended.

It is preferable that a switching device is inserted in parallel with the voltage conversion means so that the switching device is turned on and off. When the switching device is turned off, the output voltage is the same as described above, but by turning on the switching device, the output voltage V1 of the full-wave rectifier device can be directly output to the Peltier element.

The output voltage V1 is a voltage containing a large amount of ripples. However, when the Peltier element is operated in the heating mode, the existence of the ripples does not substantially matter. Therefore, the Peltier element can be driven by another new output voltage V1.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment This embodiment is a power supply device for driving a Peltier element 81 for cooling and heating. As shown in FIG. 1, a power supply device 1 of the present embodiment includes a full-wave rectifier device 10 having an output side including a smoothing capacitor 11 for converting AC to DC and removing ripples.
And the output voltage V1 of the full-wave rectifier device 10 is switched to Vo, Vo + a1, Vo + a2,.
voltage conversion means that can be switched stepwise to any voltage of o + an, a second smoothing capacitor 31 inserted in parallel with the output side of the voltage conversion means, an output side of the voltage conversion means and a Peltier element And a changeover switch 35 inserted between the switch 81 and the output switch 81 for inverting the polarity of the output voltage.

The voltage conversion means is a full-wave rectifier device 1
DC-DC converter (IC) having an output terminal p2 and an output feedback terminal p4 for converting an output voltage V1 of 0 to a base voltage Vo when the feedback signal is zero.
21 and a constant voltage circuit 22 that can be turned on and off by connecting a zener diode 221 and a switching element 222 in parallel.
And a coil 23 connected in series to the output terminal p2 of the DC-DC converter 21. Then, the voltage correction circuit is connected between the output feedback terminal p4 of the DC-DC converter 21 and the output side terminal of the coil 23, and the second smoothing capacitor 31 is connected to the output side of the coil 23.

Further, a switching device 41 is inserted in parallel with the voltage conversion means, and the switching device 41 is turned on to thereby turn on the full-wave rectifier device 10.
Can be directly output to the Peltier element 81. In FIG. 1, a terminal p1 of the DC-DC converter 21 is an input terminal, a terminal p5 is a control signal input terminal for the converter, and a reference numeral 33 is a switching transistor for supplying a control start signal. Reference numeral 51 denotes a commercial power supply, and reference numeral 52 denotes a transformer.

The following is a supplementary explanation for each. This example is a power supply device 1 of a Peltier element for cooling and heating used for a pet bed or the like. The commercial power supply 51 has a rated voltage of 1
00V, but fluctuates between about 90-110V. The voltage is reduced by the transformer 52, and the full-wave rectifier circuit 10
And smoothing capacitor 11 (3300-68
(00 μF). Its output voltage V1 is about 2
This is a DC 12 V voltage including a ripple component of ３3 V (pp).

When the switching device 41 is turned on, the output voltage V1 remains unchanged from the Peltier device 81.
Supplied to When the Peltier element 81 is used in the heating (heating) mode, there is no problem even if there is a ripple. The heating mode and the cooling (heat absorption) mode are controlled by inverting the polarity of the output voltage by the changeover switch 35, and when the heating is to be the strongest, the highest voltage is obtained by turning on the switching device 41. Applied to the Peltier element 81.

When the switching device 41 is off, the output of the voltage conversion means is supplied to the Peltier element 81 as described below. DC-D in front of voltage conversion means
The C converter 21 is an IC element of a one-chip DC-DC converter having an output feedback terminal p4, and outputs the base voltage Vo when the feedback voltage Vf at the terminal p4 is zero. Then, the feedback voltage Vf changes as follows depending on the operation state of the constant voltage circuit 22.

That is, as shown in FIG.
Is single, and when the transistor switching element 222 of the constant voltage circuit 22 is on, the feedback voltage V
f is substantially zero, the base voltage Vo is output, and when the transistor switching element 222 of the constant voltage circuit 22 is off, the feedback voltage Vf is
The Zener voltage Va of 21 is fed back, and the output voltage shifts to (Vo + Va).

The base voltage Vo is about 7 VDC.
And the included ripple voltage is about 0.1 V (pp)
And the frequency of the ripple is about 60 kHz. Therefore, the second smoothing capacitor 31 is set at 330-1.
2,000 μF, and the coil 23 is about 100 μH, 3
A. Therefore, the first and second smoothing capacitors 1
Even when the coils 1 and 31 and the coil 23 are combined, the size is smaller than that of the conventional smoothing capacitor 911.

The inexpensive and small-sized constant voltage circuit 22
Are connected in series, the output voltage can be increased stepwise. That is, of the plurality (n) of the same constant voltage circuits 22, for example, i constant voltage circuits 2
When the switch 2 is turned on (the switching element 222 is turned off), the added value of the voltages of the turned on constant voltage circuits 22 is added to the base voltage Vo and output. That is, the i constant voltage circuits 22 are turned on (switching element 2
22 is turned off), the output voltage is (Vo + i ×
Va). Therefore, the output voltage is Vo to (Vo + n ×
Va) can be changed stepwise at equal intervals.

The constant voltage circuit 22 used in the feedback circuit for changing the number of output voltages is composed of control elements, and has a small current capacity (power) (the zener diode 221 and the switching element 22).
2), the size of the constant voltage circuit 22 is small and inexpensive. Therefore, even if the number of the constant voltage circuits 22 is increased, the increase in cost and space is reduced.

That is, in the case of the conventional power supply device 900 having a voltage adjusting function shown in FIG.
Elements 31 to 933 turn on and off the load.
933 is expensive and large. As shown by a straight line 69 in FIG. 2, the cost and the size increase greatly in proportion to the number of voltage steps that can be switched. On the other hand, in the power supply device 1 of the present example, as shown by the straight line 61 in FIG. 2, even if the number of steps of the output voltage that can be switched is increased, the increase in cost and space is reduced.

As described above, according to this embodiment, the number of output voltages is increased and the Peltier element 81 is kept at a low cost and small size.
Can be appropriately controlled. That is, at the time of start-up, the voltage is gradually increased step by step to reduce the electric shock to the Peltier element, and by applying an appropriate output voltage to the Peltier element, the cooling and heating is efficient and has good control characteristics. Control characteristics can be obtained.

[0034]

As described above, according to the present invention, it is possible to obtain a small and inexpensive power supply device for a Peltier element for cooling and heating, which can change the output voltage in a stepwise manner.

[Brief description of the drawings]

FIG. 1 is a connection diagram of a power supply device according to an embodiment.

FIG. 2 is a diagram schematically illustrating an aspect of an increase in cost when the number of steps of an output voltage is changed in the power supply device according to the embodiment, as compared with a conventional device.

FIG. 3 is a circuit diagram (simplified type) of a conventional Peltier element power supply device.

FIG. 4 is a circuit diagram of a conventional Peltier device power supply device (with a voltage adjusting function).

[Explanation of symbols]

 10. . . 21. full-wave rectifier circuit, . . DC-DC converter, 22. . . Constant voltage circuit, 23. . . Coil, p2. . . Output terminal, p4. . . Output feedback terminal,

Claims (3)

[Claims] 1. A power supply device for driving a Peltier element for cooling and heating, comprising: a full-wave rectifier device having a smoothing capacitor for converting AC to DC and removing ripples; and an output voltage of the full-wave rectifier device. V1 is switched to Vo, Vo + a1, Vo + a2,.
voltage conversion means that can be switched stepwise to any voltage of o + an, a second smoothing capacitor inserted in parallel at the output side of the voltage conversion means, an output side of the voltage conversion means and a Peltier element. And a changeover switch inserted between the full-wave rectifier device and the output terminal for converting the output voltage V1 of the full-wave rectifier device to the base voltage Vo when the feedback signal is zero. -D with output and output feedback terminal
A constant-voltage circuit A1, A which can be turned on and off by connecting a C converter, a Zener diode and a switching element in parallel
2,.. An and a coil connected in series to the output terminal of the DC-DC converter. -A power supply device for a Peltier device, wherein the power supply device is connected between an output feedback terminal of a DC converter and an output side terminal of a coil, and the second smoothing capacitor is connected to an output side of the coil. 2. The output voltage V1 of the full-wave rectifier device can be directly output to a Peltier device by inserting a switching device in parallel with the voltage conversion means and turning on the switching device. A power supply device for a Peltier device. 3. The constant voltage circuits A1, A2,... An according to claim 1, wherein the voltages of the Zener diodes of the constant voltage circuits A1, A2,.
.. A power supply device for a Peltier device, wherein the output of the voltage conversion means is changed stepwise to (Vo + i × Va) by changing the number i for turning off the switching element in An.