JP2006073628A - Pwm driving method and pwm driver for peltier element, on-board temperature controller and car seat temperature controller, pwm driving characteristic chart of peltier element and method for preparing and utilizing the same, and method for testing pwm driving characteristic of peltier element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PWM driving technology which can exhibit a COP high in Peltier element can be enhanced. <P>SOLUTION: The PWM driving device sets a PWM frequency at 100 Hz or more and modulates a driving voltage applied to a Peltier element at a pulse width. Thus, the COP of the Peltier element can be improved when compared with a conventional case of around 40 Hz, permitting a power saving effect. When the Peltier element is driven by PWM, as the PWM frequency is made higher within a saturated frequency Fs (e.g. 1 kHz) or less, a higher COP can be obtained as long as there is no inconvenience in terms of cost and noise. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the field of thermoelectric technology for PWM driving a Peltier element.

  Here, the Peltier element (Peltier element) is also referred to as a thermoelectric element, and is an element having a thermoelectric effect or a Peltier effect (Peltier effect). PWM (Pulse Width Modulation) is also referred to as pulse width modulation.

(Conventional technology)
In some high-end passenger cars on the market at the time of filing of the present application, air that has been appropriately temperature-controlled is blown to the part of the car seat that the passenger's body touches, so that the passenger can spend more comfortably. Some of them are equipped with a car seat temperature control device.

  This car seat temperature control device includes a Peltier element that heats or cools air supplied from a blower by a thermoelectric effect, and a drive device that applies a PWM (pulse width modulation) drive voltage to the Peltier element. is doing. And this drive device can change the effective voltage by changing the duty ratio of a drive voltage, and can adjust the heating output and cooling output which a Peltier device exhibits.

  By the way, in such a car seat temperature control device, the Peltier element is PWM-driven using the battery as a DC power source, but the PWM frequency is set low (specifically, about 40 Hz). The reason why such a low PWM frequency is adopted is supposed to be to reduce the manufacturing cost of the PWM drive device or to prevent noise propagation of the in-vehicle audio device to the AM radio.

(Literature known technology)
For reference, for example, the following patent documents are disclosed regarding the PWM drive technology of the Peltier element.

  First, Patent Document 1 discloses a technology that uses a transistor as a switching element and suppresses heat generation in the vicinity of the Peltier element. Patent Document 2 discloses a technique for monitoring an operation state of a Peltier element by detecting a Seebeck voltage between applied voltages of PWM drive. Further, Patent Document 3 discloses a technology for radiating heat by connecting a power element used for PWM driving of a Peltier element to an exhaust heat member.

However, in these patent documents, there is no description specifying the PWM frequency of the drive voltage applied to the Peltier element, and there is no description about the relationship between the level of the PWM frequency and the efficiency of the thermoelectric effect exhibited by the Peltier element.
JP-A-7-295659 JP 2001-336853 A JP 2001-345486 A

(Background to Invention)
By the way, the applicant has been researching on the PWM driving technology of the Peltier element, but when the inventors conducted a test to measure the COP indicating the operation efficiency of the Peltier element, the COP is unexpectedly low in the region where the PWM frequency is low. It turned out to be low.

  For example, the COP when the Peltier element is cooled is about 2.8 in a 2V DC drive, whereas in a 2V PWM drive with the same effective voltage, the PWM frequency is 1 at 40 Hz. Only about COP of about 1.1 is exhibited at about .7 and 10 Hz. That is, when the Peltier element is PWM driven with an effective voltage of 2V, the COP is almost halved when the PWM frequency is several tens of Hz, compared to the case where the DC frequency is driven with the same 2V. It turned out that it is so remarkable that it is low.

  In other words, in the conventional car seat temperature control device, the PWM frequency of the drive voltage applied to the Peltier element is about 40 Hz as described above, so that the COP of the Peltier element is compared with the case of DC drive. It should be quite low. Therefore, in this prior art, it is apparent that a large amount of power is consumed by the Peltier device as compared with the case of direct current drive in order to obtain a desired cooling effect by low frequency PWM drive. This is not desirable as a vehicle-mounted device, and is even more inconvenient in view of the fact that high-end passenger cars equipped with this device generally use a lot of electrical components and have a severe power supply-demand relationship.

  However, if the COP of the Peltier element is better for the DC drive than the PWM drive, it is never the case whether a variable voltage DC drive device should be mounted on the vehicle. This is because, in order to make the cooling output of the Peltier element variable by direct current drive, an amplifier element with large heat dissipation such as a power transistor is required as a circuit element of the drive device in order to adjust the applied voltage level of direct current drive. Because. As a result, the amount of heat radiation of the drive circuit increases, and the improved cooling efficiency is offset. Therefore, the variable voltage DC drive device is 10% lower than the conventional PWM drive device. The cooling efficiency will drop soon.

(First problem of the present invention)
Therefore, the present invention provides a Peltier element that can drive a Peltier element with a higher COP while taking advantage of a simple and lightweight structure of the driving device, low cost, high reliability, and low loss due to heat generation. Providing drive technology is the first issue to be solved. In addition, another object of the present invention is to provide an in-vehicle temperature control device and a car seat temperature control device that have few disadvantages compared to the prior art and can reduce power consumption while obtaining an equivalent cooling action.

(Second problem of the present invention)
The present invention further provides a characteristic chart showing the relationship between the COP exerted by the PWM driven Peltier element and the PWM frequency in a very simple manner as a research result of the inventors. To do. In addition, another object is to provide a method for drawing and using this characteristic chart. It is another object of the present invention to provide a method for significantly reducing the time required for the measurement test for obtaining the PWM drive characteristic of the Peltier element by applying this characteristic chart.

  In order to solve such a problem, the inventors of the present application have conducted tests and invented the following means. Here, each means classified in the first part is an invention for solving the first problem described above, and each means classified in the second part is an invention for solving the second problem described above. It is. The number of each means corresponds to the serial number of each claim listed in the claims at the time of filing of the present application.

-Part 1: Peltier device PWM drive technology [Drive method]
(First means)
The first means of the present invention is to apply a PWM (pulse width modulation) drive voltage with a predetermined PWM frequency and duty ratio to a Peltier element and to exert a thermoelectric effect on the Peltier element. It is. The feature of this means is that the PWM frequency is 100 Hz or more.

  In this means, the PWM frequency is higher than that of the prior art, and the drive voltage is applied to the Peltier element at a PWM frequency of 100 Hz or higher, so that the COP (operation efficiency) of the Peltier element is increased. Thus, the tendency for the COP of the Peltier element to improve as the PWM frequency increases is more conspicuous as the duty ratio is lower (that is, the effective voltage is lower). As a result, if the object is heated or cooled by the Peltier effect, and the Peltier element wants to exhibit a predetermined heat output, the power consumption required by the Peltier element is reduced.

  In addition, in order to adjust the effective voltage applied to the Peltier element, a PMW driving method that adjusts the effective voltage with the duty ratio can be used. Therefore, heat generation in the drive circuit that generates an applied voltage compared to the case where the Peltier element is driven by DC is used. Is small. Here, since the generation of Joule heat cancels out the cooling action, if the heat generation in the drive circuit is small as described above, the improvement of the COP including the drive circuit due to this causes the cooling action to be exerted. Become more prominent. In addition, if the PMW driving method is adopted, the number of parts constituting the driving circuit can be reduced, so that the driving device becomes cheaper and the reliability thereof becomes higher.

  Therefore, according to the present means, the Peltier element can be driven with a higher COP while taking advantage of the PWM drive device that is simple and light in weight, is low in price, highly reliable, and has little loss due to heat generation. There is an effect. As a result, there is an effect that power consumption in the entire thermoelectric system of the Peltier element including the driving device is reduced, and this effect is more remarkable during the cooling operation.

(Second means)
The second means of the present invention is a “Peltier element PMW driving method” according to the first means, wherein the PWM frequency is 400 Hz or more.

  In this means, since the PWM frequency is higher than that in the prior art, the COP of the Peltier element is further improved. Therefore, according to this means, there is an effect that the effect of the first means is further enhanced.

(Third means)
A third means of the present invention is the “Peltier element PMW driving method” characterized in that, in the first means described above, the PWM frequency is higher and is 1 kHz or more.

  In this means, since the PWM frequency is limited to be higher than that of the prior art, the COP of the Peltier element is further improved, and is increased to the same level as the direct current drive having the same voltage as the effective voltage of the PMW drive. Therefore, according to this means, the operation and effect of the first means described above are further enhanced, and the COP is increased to the same level as that of the DC drive.

[Driver]
(Fourth means)
The fourth means of the present invention supplies power from a predetermined power source, applies a PWM (pulse width modulation) drive voltage with a predetermined PWM frequency and duty ratio to the Peltier element, and gives the Peltier element a thermoelectric effect. It is a “Peltier element PMW drive device” to be exhibited. The feature of this means is that the PWM frequency is 100 Hz or more.

  In this means, an operation substantially similar to that of the first means described above can be obtained. Therefore, according to the PWM drive device of this means, the circuit configuration is simple, light weight, low price, high reliability, and low loss due to heat generation, while maintaining the advantages of higher COP and Peltier elements. There is an effect that can be driven. As a result, an effect that power consumption in the entire thermoelectric system of the Peltier element including the PMW driving device is reduced is obtained, and this effect is more remarkable during the cooling operation.

(5th means)
A fifth means of the present invention is the “PMW drive device for Peltier element”, characterized in that, in the above-mentioned fourth means, the PWM frequency is 400 Hz or more. According to this means, the effect equivalent to the above-mentioned second means can be obtained.

(Sixth means)
The sixth means of the present invention is the “PMW drive device for Peltier element” characterized in that, in the above-mentioned fourth means, the PWM frequency is higher and is 1 kHz or more. According to this means, the operation and effect equivalent to the third means described above can be obtained.

(Seventh means)
The seventh means of the present invention is the “PMW drive device for Peltier element” characterized in the power source and the drive device in the fourth means described above. That is, the feature of this means is that the power source is a DC power source, and that the driving device generates a predetermined rectangular wave voltage according to a predetermined control signal, and amplifies the rectangular wave voltage to amplify the rectangular wave voltage. And amplifying means for applying a driving voltage to the Peltier element.

  In this means, since the DC power supply supplies power to the PWM drive device having the waveform generation means and the amplification means, the device price is low, the reliability is high and the Joule heat is small with a simple configuration of the PWM drive device. The advantage of ending is often demonstrated. Therefore, according to this means, there is an effect that the effect of the fourth means becomes stronger, and if this means is further combined with the fifth means or the sixth means, the tendency to strengthen the effect becomes more remarkable.

[In-vehicle device]
(Eighth means)
The eighth means of the present invention controls a Peltier element that performs at least one of cooling and heating by the thermoelectric effect, PWM driving the Peltier element, and the PMW driving apparatus. It is an “in-vehicle temperature control device” characterized by having a control device.

  As a general trend, the amount of power that can be supplied by a vehicle such as an automobile is limited. Therefore, in-vehicle devices have more demands for power saving than devices that receive power from external power sources such as commercial power sources. Is more compelling. In addition, in-vehicle devices are generally stricter than other devices in terms of device price, device weight, reliability, and the like.

  The “on-vehicle temperature control device” of this means has a high COP in the Peltier element as described above in the section of the fourth means, and the operating efficiency of the entire system including the drive device is high (especially high during cooling). Also, the equipment price, equipment weight and reliability are excellent. Therefore, according to the “vehicle temperature control device” of this means, the power consumption is smaller than that of the prior art, but other advantages are not lost, and therefore, there is an effect that it is particularly suitable as the vehicle device. Such an effect is more remarkable when the PWM drive device of this means is a combination of the fifth means or the sixth means and the seventh means.

(Ninth means)
According to a ninth means of the present invention, in the eighth means described above, the control device controls the PWM drive device to set the PWM frequency when a predetermined one of the in-vehicle receiving devices is operating. It is an “in-vehicle temperature control device” characterized by having a function of reducing.

  In this means, for example, when a car audio AM radio receiver is operating, the PWM frequency of the PWM drive device is lowered, and radio noise that is likely to occur when the Peltier element is PWM driven is reduced. Therefore, according to this means, there is an effect that it is difficult for noise to enter the car radio or the like even when the on-vehicle temperature control device of this means is in operation.

(Tenth means)
According to a tenth means of the present invention, in the “vehicle temperature control device” of the eighth means described above, the temperature adjustment target of the Peltier element is at least one of a seat surface and a backrest of a car seat. "Car seat temperature control device".

  As described above in the section of the eighth means, this means requires less power consumption than the prior art and does not lose advantages such as the equipment price, equipment weight, and reliability. In addition, car seat temperature control devices are currently installed only in high-end passenger cars, and in such vehicles, electrical components are heavily used and power consumption is large, and there is a chronic shortage of power. The effect of reducing power consumption is great. Therefore, according to the “car seat temperature control device” of this means, the effect of the eighth means that the power consumption is smaller than that of the prior art without losing other advantages becomes even more valuable.

  Such an effect is more remarkable when the PWM drive device of this means is the fifth means or the combination of the sixth means and the seventh means. In addition, if the ninth means is combined with this means, it is difficult for noise to enter a car radio or the like, and it is more suitable as a mounting device for a luxury passenger car.

Part II: Peltier element PWM drive characteristic chart and related technology The present invention further relates to the relationship between the PWM frequency of the drive voltage and the COP of the Peltier element as a research result derived from the aforementioned PWM drive technique of the Peltier element. Provides a characteristic chart that is very concise. In addition, the drawing method, a simple test method based on the drawing method, and a method of using the chart are provided.

[Characteristic chart]
(Eleventh means)
The eleventh means of the present invention applies a drive voltage that is PWM (pulse width modulated) with a predetermined PWM frequency and duty ratio to the Peltier element to cause the Peltier element to exert a thermoelectric effect. It is a “Peltier element PWM drive characteristic chart” showing the relationship among the three parameters among various parameters related to drive characteristics. The first feature of this means is that it is a semi-logarithmic graph in which the PWM frequency of the drive voltage is taken on the logarithmic horizontal axis and COP indicating the operation efficiency of the Peltier element is taken on the vertical axis. The second feature of this means is that either the duty ratio or the effective voltage of the drive voltage is fixed to at least one predetermined value, and the relationship between the PWM frequency and the COP is determined for each of the predetermined values. The diagonal line segment with the positive inclination shown is drawn.

  That is, this means is a semi-logarithmic graph in which a straight line (an oblique line segment) rising to the right is drawn, the horizontal axis is the logarithmic PWM frequency, and the vertical axis is the COP of the Peltier element. One oblique line is drawn for each predetermined value of the duty ratio (or effective voltage). This means is a characteristic chart created by the inventors in the process of organizing the test results at the variable frequency related to the PWM drive characteristics of the Peltier element, and was developed based on the inventors' new knowledge. .

  In this means, the relationship between the PWM frequency at a predetermined duty ratio (or effective voltage) of the drive voltage applied to the Peltier element and the COP exerted by the Peltier element is one straight line up to the predetermined frequency. It is represented by the diagonal line segment in the above-mentioned semilogarithmic graph. Therefore, the PWM drive characteristics at a plurality of duty ratios (effective voltages) can be shown very simply in the graph with the same number of diagonal lines. This is extremely suggestive in organizing the COP frequency characteristics exhibited by the Peltier element driven by PWM. In addition, since it is only necessary to draw a straight diagonal line segment, it is different from the case where the characteristic becomes a curve as in an ordinary graph. However, drawing is really easy, and therefore there is no error due to the selection of the approximate curve.

  If the characteristic chart of this means is used, not only the drawing is easy, but there are a number of advantages as shown in the means described later. For example, as will be described later in the 16th means, the frequency characteristic test of the Peltier device PWM drive device is simplified and the time required for the test is greatly reduced, and the utility value is the same as the result of testing over a long period of time. Certain test data can be provided. Further, as will be described later in the seventeenth means, if the characteristic chart of this means is converted, it is easy to draw a secondary characteristic chart necessary for designing a Peltier element PWM drive device.

  Therefore, according to this means, there is an effect that the frequency characteristics of COP exhibited by the Peltier element driven by PWM can be simply arranged in a new format. As a result, in order to obtain test data necessary for designing the PWM drive device of the Peltier element, the time required for the test for measuring the COP using the duty ratio (effective voltage) of the drive voltage and the PWM frequency as parameters, There is an effect that it can be greatly shortened.

(Twelfth means)
The twelfth means of the present invention is a “Peltier element PWM drive characteristic chart” characterized in that, in the eleventh means described above, at least one polygonal line is drawn in the semilogarithmic graph. The means has the diagonal line segment in the region where the PWM frequency is equal to or lower than the predetermined frequency, and has a horizontal line segment in the region where the PWM frequency is higher than the predetermined frequency, and the diagonal line segment and the horizontal line segment are continuous at the predetermined frequency. It is characterized in that at least one broken line is drawn.

  In other words, the characteristic of the polygonal line drawn in the semilogarithmic graph is the oblique line segment described in the eleventh means in the region where the PWM frequency is equal to or lower than the predetermined frequency, and the horizontal line in the region above the predetermined frequency. The diagonal line segment and the horizontal line segment are continuous at the predetermined frequency. Note that this “predetermined frequency” (a bending point of a broken line, that is, a PWM frequency having a “COP saturation point” to be described later in the meaning 14 means) corresponds to a “saturation frequency” in the 15th means described later.

  In the eleventh means described above, only the diagonal line segment is drawn in the semilogarithmic graph, and if this diagonal line segment is extended to the high frequency side, the COP increases as much as possible. It is irrational. Therefore, in this means, when the PWM frequency exceeds a predetermined value (predetermined frequency), this diagonal line segment becomes a horizontal line segment that is horizontally extended by a predetermined COP.

  This is confirmed after the inventors conducted a PWM drive characteristic test for measuring the COP of the Peltier element up to a considerably high frequency range, having doubts about the test data compiled in the characteristic chart of the eleventh means. It was possible. In this way, the inventors consider that the COP of the Peltier element is saturated when the PWM frequency exceeds a predetermined frequency, which is a new finding.

  Therefore, according to this means, the semi-logarithmic characteristic chart can be made effective not only in the PWM frequency region below the predetermined frequency (saturation frequency) but also in the region exceeding the predetermined frequency. Therefore, according to the characteristic chart of this means, there is an effect that the frequency characteristic of the COP can be indicated by a very simple broken line at almost all PWM frequencies at which the Peltier element can be PWM driven.

  Moreover, as can be concluded from the fifteenth means described later, a plurality of diagonal line segments are drawn only in the low frequency region when this characteristic chart (this means), which is paradoxical but effective up to the high frequency region, is completed. There is even an effect that drawing can be performed with a smaller number of measurement points than the characteristic chart (11th means).

[Characteristic chart drawing method]
(13th means)
The thirteenth means of the present invention is “a method for drawing a Peltier element PWM drive characteristic chart”. That is, this means applies a rectangular wave drive voltage having a predetermined effective voltage that is pulse-width modulated at a predetermined PWM frequency and duty ratio to a Peltier element, and measures the COP of the thermoelectric effect exhibited by the Peltier element. To create a Peltier element PWM drive characteristic chart according to claim 11. The feature of this means is to draw the characteristic chart according to claim 11 as follows.

  That is, the above-described COP measurement test is performed on the first frequency that is a relatively low PWM frequency and the second frequency that is a relatively high PWM frequency. (However, the first frequency and the second frequency are both set below the PWM frequency “saturation frequency” at which the COP is saturated.) The measurement results of the COP at the first frequency and the second frequency are respectively One COP and the second COP.

  Further, the first measurement point determined by the first frequency and the first COP and the second measurement point determined by the second frequency and the second COP are taken with the PWM frequency on the logarithmic horizontal axis, and the COP is vertically Plot on a semilogarithmic graph on the axis. Then, an oblique line segment having a positive slope including the first measurement point and the second measurement point in the middle or at the end is drawn on the semilogarithmic graph, and the characteristic chart according to claim 11 is drawn. To do.

  In this means, in the test for measuring the PWM frequency characteristics of the COP exhibited by the Peltier element, the COP measurement at the first frequency and the second COP measurement are performed while the duty ratio of the PWM drive voltage is kept constant (that is, the effective voltage is constant). Only two measurement tests with COP measurement at frequency are required. That is, the PWM frequency characteristic of the COP exhibited by the Peltier device at a predetermined duty ratio or effective voltage is measured on the characteristic chart according to claim 11 only by measuring two points of the first measurement point and the second measurement point. It is defined by the diagonal line segment of the book. The fact that a characteristic test can be completed by measuring only two points in this way means that a characteristic test can be performed in consideration of the fact that the conventional test method required at least several measurements to obtain the same characteristic data. This means that the time required is halved or halved. Of course, if a plurality of levels with a predetermined duty ratio (or effective voltage) are tested, the same number of diagonal lines can be drawn in a semilogarithmic graph, and the characteristic chart can be made more complete.

  Therefore, according to this means, the time required for the PWM frequency characteristic test for obtaining the COP of the Peltier element can be greatly shortened by applying the characteristic chart of the eleventh means.

(14th means)
The fourteenth means of the present invention draws and adds at least one broken line in which a predetermined horizontal line continues to the diagonal line segment drawn by the above-mentioned thirteenth means. "Characteristic chart drawing method".

  The feature of the drawing method of this means is that this broken line is drawn as follows. That is, when a DC voltage equal to the effective voltage is applied to the Peltier element, a COP exerted by the Peltier element is defined as a DC COP, and a horizontal line segment corresponding to the DC COP is drawn higher than the oblique line segment. . Then, a point where the diagonal line segment drawn by the thirteenth means intersects with the horizontal line segment is defined as a COP saturation point at the effective voltage, and the diagonal line segment and the horizontal line segment are continuous at the COP saturation point. At least one line is drawn. Here, each broken line represents a PWM drive characteristic at a predetermined duty ratio (or effective voltage).

  In this means, when drawing the characteristic chart corresponding to the above-mentioned twelfth means, the drawing method of the thirteenth means is used in the low frequency region where the PWM frequency is not more than a predetermined frequency among the broken lines, and the high frequency region above the predetermined frequency Then, a horizontal line segment is drawn at the level of DC COP.

  By the way, the COP (direct current COP) when the Peltier element is driven by direct current is usually already obtained for a representative level of the applied voltage. That is, since the DC drive characteristic is more basic than the PWM drive characteristic, in most cases, the DC COP of the Peltier element is determined by the manufacturer before starting the PWM frequency characteristic test for the COP of the Peltier element. Or have already been sought in the DC drive test. Even if the direct current COP has not yet been obtained, the direct current COP of the Peltier element can be easily obtained using the equipment used for the PWM drive characteristic test.

  Therefore, according to the drawing method of this means, the horizontal line segment of the level corresponding to the DC COP at the DC voltage of the same level as the effective voltage is drawn on the oblique line segment of the characteristic chart drawn by the 13th means described above. If you add, you can easily complete the polyline. As a result, a complete characteristic chart that is effective up to the high-frequency region exceeding the PWM frequency (saturation frequency) at which the COP of the Peltier element saturates is completed with the same effort as the thirteenth means, requiring no additional test. There is an effect that can be done. Furthermore, there is also an effect that the PWM frequency at which the COP of the Peltier element saturates (“saturation frequency” defined by the fifteenth means) can be easily obtained.

(15th means)
The fifteenth means of the present invention is a "Peltier element utilizing the characteristic that the saturation frequency is common to each broken line even if the effective voltage level (that is, the duty ratio level) changes in the above-mentioned fourteenth means. "Drawing method of PWM drive characteristic chart".

  The feature of this means is as follows. First, at least one of the polygonal lines is drawn on the semilogarithmic graph, and the PWM frequency at the COP saturation point of the polygonal lines is determined as a “saturation frequency” common to the effective voltages. . Secondly, for other effective voltages, the COP is measured in a PWM frequency region lower than the saturation frequency to obtain at least one measurement point, an oblique line segment passing through the measurement point, and the saturation frequency. On the high frequency side, a horizontal line segment corresponding to a DC voltage equal to the effective voltage is to draw a continuous broken line at this saturation frequency. Note that these two features have some portions that can be moved back and forth.

  In this means, if at least two measurement points (first measurement point and second measurement point in the thirteenth means) are obtained for one predetermined effective voltage, one measurement is made for each of the other effective voltages. A characteristic chart in which a plurality of broken lines are drawn can be completed simply by measuring COP at points.

  That is, first, if a single broken line is drawn by the drawing method of the fourteenth means, the saturation frequency can be obtained from the broken line. Then, assuming that the saturation frequency is common to other effective voltages, diagonal lines are drawn upward from one measurement point for each of the other effective voltages. When drawing this diagonal line segment, the right end of the diagonal line segment is the COP saturation point of the horizontal line segment corresponding to the direct current COP at the same applied voltage level as the effective voltage. This COP saturation point is easily determined by taking a point located at the same PWM frequency (saturation frequency) as the bending point of the first broken line (the COP saturation point) of the horizontal line segment. As a result, the second and subsequent polygonal lines are drawn on the semilogarithmic graph by obtaining only one measurement point for each duty ratio (or effective voltage).

  Therefore, according to the present means, if at least two measurement points are obtained for one predetermined effective voltage, a plurality of broken lines are drawn only by measuring COP at one measurement point for each of the other effective voltages. There is an effect that a completed characteristic chart can be completed. As a result, although somewhat paradoxical, it is better to complete this characteristic chart that is effective not only in the low-frequency region but also in the high-frequency region exceeding the saturation frequency, in which only a plurality of diagonal line segments are drawn in the low-frequency region. As a result, an unexpected effect that the time required for the characteristic test can be further shortened can be obtained.

[Characteristic test method]
(16th means)
The sixteenth means of the present invention is performed in accordance with the Peltier element PWM drive characteristic chart drawing method described in any one of the thirteenth to fifteenth means described above. Characteristic test method ".

  In this means, as already explained in the sections of the thirteenth to fifteenth means, if a COP measurement test at the time of Peltier element PWM driving is performed for the purpose of drawing these characteristic charts, it is much less than in the prior art. The PWM drive characteristics of the Peltier element can be measured with the number of measurement points. In particular, if a test is performed in accordance with the drawing method of the fifteenth means, the PWM driving characteristics of the COP exhibited by the effective Peltier element up to a high frequency region exceeding the saturation frequency can be measured in a very short time. Therefore, according to this means, there is an effect that a more complete characteristic chart can be obtained while shortening the time of the measurement test.

[How to use characteristic chart]
(17th means)
The seventeenth means of the present invention is a “method of using a PWM drive characteristic chart”, which is converted based on the PWM drive characteristic chart of the Peltier element described in the eleventh means and converted into a PWM drive apparatus. This is a method of drawing a secondary chart that is easy to use for design. That is, the feature of this means is that, based on the characteristic chart of the eleventh means, either the duty ratio or the effective voltage is on the horizontal axis, the COP is on the vertical axis, and at least one of the PWM frequency ranges. To draw a “secondary characteristic chart” in which a curve is drawn for each predetermined value.

  This means obtains a secondary characteristic chart in which the characteristic is drawn in a curve for a predetermined PWM frequency with the COP of the Peltier element as the vertical axis and the duty ratio or effective voltage as the horizontal axis. Such a chart is suitable as a document for designing a PWM drive device in which the COP or output of the Peltier element is adjusted by changing the duty ratio (effective voltage) while keeping the PWM frequency at a predetermined value.

  Since this secondary characteristic chart is obtained secondarily based on the above-mentioned characteristic chart, it can be drawn in a short time based on a very small number of measurement points as already explained in the section of the sixteenth means. . Moreover, since the above characteristic chart is a semi-logarithmic graph in which a plurality of diagonal lines or polygonal lines are drawn straight, even if the number of measurement points as a basis is small, it is based on the coordinate conversion to the secondary characteristic chart. You can get a lot of data with sufficient density. As a result, the curve group drawn on the secondary characteristic chart is interpolated more smoothly than the graph of the same type created by taking a large number of measurement points over a long time.

  Therefore, according to this means, a secondary characteristic chart that is convenient for designing a PWM drive device for a Peltier element can be easily obtained by simply converting the coordinates of the above characteristic chart, and the curve group becomes smooth. effective.

(18th means)
The eighteenth means of the present invention is to design any one of the fourth to tenth means based on the secondary characteristic chart of the seventeenth means. Method.

  In this means, a device capable of PWM driving a Peltier device with a high COP while taking advantage of PWM driving is prepared using a secondary characteristic chart drawn based on data that can be prepared in a short measurement test as a document. be able to. Therefore, according to this means, there is an effect that the PWM drive device can be designed in a shorter time after a Peltier element having new characteristics is developed.

  And in addition to being able to develop such excellent products, the design and development period (lead time) can be shortened. It can be a big advantage in gaining an advantage in the competition.

[Characteristic chart (2)]
(19th means)
The nineteenth means of the present invention is a chart showing the mutual relationship among the three parameters related to the PWM drive characteristics of the Peltier element. Here, the three parameters are the “PWM frequency” and “duty ratio” (or “effective voltage”) of the pulse-width-modulated drive voltage applied to the Peltier element, and the Peltier effect exhibited by the Peltier element. It is “COP” indicating the operation efficiency of

  The feature of this means is as follows. That is, the first feature is that the vertical axis of the chart is the real axis of the COP, the horizontal axis of the chart is the logarithmic axis of the PWM frequency, and the chart is a semi-logarithmic graph. The second feature is that on the semilogarithmic graph, there is one diagonal line segment having a positive slope with respect to one predetermined value of the duty ratio, and a predetermined frequency continuous to the diagonal line segment. Among the broken lines having a horizontal line segment with no inclination, at least the former is drawn.

  This means generally corresponds to the above-mentioned eleventh means or twelfth means, and has substantially the same function and effect. Therefore, means corresponding to the thirteenth means to the eighteenth means can be implemented in relation to this means, and operational effects corresponding to the respective means can be obtained.

(Category)
The characteristic charts of the eleventh means, the twelfth means and the nineteenth means correspond to the invention of the object, and the drawing methods of the thirteenth means to the fifteenth means are methods for drawing the characteristic chart. ). The test method of the sixteenth means corresponds to the method invention, and the chart utilization method of the seventeenth means corresponds to the invention of the manufacturing method because it is a method of drawing a secondary characteristic chart. Further, the chart utilization method of the eighteenth means is essentially a method of designing an apparatus, and thus corresponds to the invention of the manufacturing method.

[Background of research]
In the course of developing a car seat temperature control device having a Peltier element and its PWM drive device, the inventors have prepared a Peltier element characteristic test apparatus for measuring the COP of the Peltier element driven by PWM.

  As shown schematically in FIG. 1, this test apparatus has a commercially available Peltier element 1 to be tested, and a frequency generator 5 that applies a pulse-width-modulated drive voltage fed from a commercial power source to the Peltier element 1. And a blower 6 for blowing air at a desired flow rate to the Peltier element 1. The frequency generator 5 is a test device capable of generating various waveforms. For example, the rectangular wave voltage, duty ratio (and therefore effective voltage), PWM frequency, etc. of the rectangular wave pulse train of the PWM drive voltage are specified within a predetermined range. Thus, an applied voltage for PWM driving can be generated. Although the oscillograph is attached to the frequency generator 5, it has been confirmed that the pulse waveform of the frequency generator 5 is not disturbed until the frequency reaches a considerably high frequency.

  Here, when the Peltier device 1 is PWM-driven, even if the top voltage of the rectangular pulse wave is constant, the effective voltage can be adjusted by changing the duty ratio. That is, as a general theory, when it is desired to PWM drive the Peltier device 1 at the same level as the DC voltage (see FIG. 1A) with a high ratio, a high duty ratio is set as shown in FIG. If so, an equivalent effective voltage can be applied. On the contrary, even if the rectangular wave voltage is the same, if the duty ratio of the rectangular wave is lowered as shown in FIG. 1 (d), the effective voltage equivalent to the DC voltage with a low ratio as shown in FIG. 1 (b). Can be applied.

  Now, when testing the PWM drive characteristics of the Peltier element 1 using the above-described test apparatus, the frequency generator 5 PWM-drives the Peltier element 1 under a predetermined condition, and the blower 6 moves from the blower duct 60 to the Peltier element 1. Inflow air A having a predetermined flow rate is blown. Then, the cool air C cooled by the heat absorption plate (not shown) of the Peltier element 1 is exhausted from the cool air duct 61, and conversely, the warm air W heated by the heat dissipation plate (not shown) of the Peltier element 1 is warm air. The air is exhausted from the duct 62. At this time, the flow rate, temperature, and the like of the incoming air A, the cold air C, and the hot air W are measured by a measuring unit (not shown) and recorded in a recording unit (not shown). Thus, if the cooling capacity and heating capacity of the Peltier element 1 and the power consumption of the Peltier element 1 that is PWM-driven are known, the COP (heat output / heat efficiency) that the Peltier element 1 exhibits under that condition is known. Power consumption) can be calculated.

The inventors conducted such a test several times under different conditions, and obtained measurement results for a plurality of Peltier elements. Of these, typical test results during cooling operation are summarized in a graph as an example and shown in FIG. At this time, the following three parameters can be set as test conditions (independent variables) among the main parameters of the PWM drive characteristic test.
・ Drive voltage “rectangular wave voltage” (the power supply voltage remains unchanged and is fixed at a predetermined value)
・ "PWM frequency" of drive voltage
・ "Effective voltage" of drive voltage (= "rectangular wave voltage" x "duty ratio")

Here, assuming the application of the invention to an in-vehicle device, it is difficult to freely change the PWM driving rectangular wave voltage, and the rectangular wave voltage is difficult to change. Was fixed at a constant value (12V) and tested. Note that the flow rate of the blower 6 was uniformly 5.0 m ³ / h. Therefore, only two of “PWM frequency” and “effective voltage” (or “duty ratio”) can be freely set as test conditions. On the other hand, “COP” (Coefficient of Performance), which is the thermoelectric energy conversion efficiency of the Peltier effect exhibited by the Peltier element 1, was selected as a representative value obtained as the main measurement result (dependent variable).

  Therefore, FIG. 3 is a graph in which COP is taken on the vertical axis and effective voltage and duty ratio are taken on the horizontal axis. In this graph, there are several curves connecting the measurement results measured at the same PWM frequency. The book is drawn. Therefore, when FIG. 3 is converted, the test result is plotted with the PWM frequency as the horizontal axis, and the graph is redrawn with one curve for one predetermined value of the effective voltage, the result is as shown in FIG. 3 and 4, when the Peltier element 1 is PWM-driven, it can be seen that the COP is improved when the Peltier element 1 is driven at a higher PWM frequency than at about 40 Hz as in the prior art.

  By the way, while examining FIG. 4, the inventors suddenly noticed that the horizontal axis in FIG. 4 was changed to a logarithmic axis. Then, as shown in FIG. 5, each measured value was placed on a straight diagonal line, and the experimental results could be arranged very neatly. At this stage, the PWM frequency has been tested only up to 1000 Hz (1 kHz), but as a result of examining FIG. 5, the question of what happens to the COP when the PWM frequency increases beyond 1 kHz is It came in between. Therefore, the inventors further performed an additional test at a PWM frequency exceeding 1 kHz (specifically, 3 kHz and 10 kHz), and re-drawn these measurement data in addition to FIG. FIG. 6 is a semilogarithmic graph obtained as a result.

  As shown in FIG. 6, the inventors were able to obtain some new findings by the above test and analysis of the measurement results, and they are listed below.

  (1) In the low frequency range of about 10 Hz to 1 kHz, even if the effective voltage is kept constant, the COP of the Peltier element improves as the PWM frequency of the applied voltage increases, and the logarithm of the PWM frequency and the COP are linearly related. It is in.

  (2) When the predetermined PWM frequency (named “saturation frequency”) is reached, this linear relationship is lost. In a high frequency region exceeding the saturation frequency, the COP takes a constant value as if it was saturated. Is equal to COP (provisional name “DC COP”) when DC driving is performed with the same applied voltage as the effective voltage.

  (3) The “saturation frequency” is common even between different effective voltages (that is, even when the duty ratio is different).

  Based on the above knowledge, the inventors have invented each means disclosed in the above-mentioned means for solving means, and examples thereof will be disclosed below.

  Part 1: PWM drive technology for Peltier elements

[PWM drive technology]
(Apparatus configuration of Example 1)
As shown in FIG. 7, the “Peltier device PWM drive device” as Example 1 of the present invention is supplied with electric power from a battery 2 as a DC power source with a base angle of 2 V and applies a PWM drive voltage to the Peltier device 1. Thus, the Peltier element 1 is a device that exhibits a thermoelectric effect. The apparatus includes a waveform generating unit 51 that generates a predetermined rectangular wave voltage according to an external control signal, and an amplifying unit 52 that amplifies the rectangular wave voltage and applies a pulse width modulated (PWM) drive voltage to the Peltier element 1. And have. Here, the waveform generation means 51 is an electronic circuit that generates a rectangular wave pulse signal with a variable duty ratio, and the amplification means 52 is a power amplifier that is driven by the waveform generation means 51. The apparatus applies a drive voltage with a PWM frequency of 100 Hz or higher, which is pulse-width modulated at a duty ratio specified by an external control signal, to the Peltier element 1.

  The PWM frequency of the drive voltage applied to the Peltier element 1 by the present apparatus may be set freely according to the application as long as it is 100 Hz or higher. For example, it may be set to 400 Hz or 1 kHz. However, if the Peltier device 1 is equivalent to the one subjected to the above-described test, even if a higher PWM frequency is set exceeding 1 kHz, it is not expected to further improve the COP during the cooling operation.

(Operational effect of Example 1)
In the “Peltier device PWM drive device” of the present embodiment, the PWM frequency is set higher than that of the prior art, so that the COP of the Peltier device 1 is improved.

  That is, as shown in FIG. 6 again, for example, when the effective voltage applied to the Peltier element 1 is 2 V (the duty ratio is about 17%), the PWM frequency characteristic of the COP that is exhibited during the cooling operation is drawn in the upper part of the figure. It is represented by a broken line. Then, since the PWM frequency was about 40 Hz in the prior art, the COP exhibited by the Peltier device 1 in the prior art was only about 1.7. However, according to this embodiment, when the PWM frequency is 100 Hz, the COP at the time of cooling operation is improved to about 1.9, about 2.4 when the frequency is 400 Hz, and about 2.8 when the frequency is 1 kHz. improves. Thus, when the PWM frequency is 1 kHz, the COP increases to the same level as in the case of DC driving with the same voltage (2 V).

  The tendency for the COP of the Peltier device 1 to improve as the PWM frequency increases in this way is more conspicuous as the duty ratio is lower (that is, the effective voltage is lower), as shown in FIG. As a result, if the object is heated or cooled by the Peltier effect, and the Peltier element 1 wants to exhibit a predetermined heat output, the power consumption required by the Peltier element 1 is greatly reduced. is there.

  In addition, in order to adjust the effective voltage applied to the Peltier element 1, the PMW driving method that adjusts the effective voltage with the duty ratio is adopted, so that an applied voltage is generated as compared with the case where the Peltier element 1 is DC-driven. Heat generation in the driving device 5 of this embodiment can be small. Here, since the generation of Joule heat cancels the cooling action, if the heat generation in the PWM drive device 5 is small as described above, the improvement of the COP in the entire system including the PWM drive device 5 due to this, It becomes more remarkable when the cooling effect is exhibited. In addition, since the PMW driving method is adopted, the number of parts constituting the driving circuit of the PWM driving device 5 can be reduced, so that the device price becomes lower and the reliability thereof becomes higher.

  Therefore, according to the present embodiment, the advantages unique to the PWM drive system, such as the structure of the drive device 5 being simple, light weight, low price, high reliability, and low loss due to Joule heat generation, are maintained. ing.

  In addition, since the applicant has a track record of manufacturing a device for PWM driving a blower motor of an in-vehicle air conditioner at 5 to 20 kHz, inconveniences such as generation of radio noise and increase in device price due to an increase in PWM frequency are avoided. I am confident that I can do it.

(Driving method of Example 1)
On the other hand, the “Peltier device PWM driving method” as the first embodiment of the present invention applies a driving voltage pulse-width-modulated at a predetermined PWM frequency and duty ratio to the Peltier device 1 to produce a thermoelectric effect on the Peltier device 1. It is a method to demonstrate. A feature of the present embodiment is that the PWM frequency is 100 Hz or more, and 100 Hz, 400 Hz, 1 kHz, or the like may be appropriately set according to the application. Also by the driving method of the present embodiment, substantially the same operational effects as those described above can be obtained.

(Various variants of Example 1)
As various modifications of the present embodiment, as shown in FIGS. 8 and 9, power transistors 52A, 52B and FETs are employed as the amplifying means 52 in place of the power amplifier, and the order of connecting the Peltier device 1 and the DC power source is changed. A PWM drive device that is reversed can be implemented. Alternatively, if the circumstances of the power supply allow, a modified form (not shown) in which the power supply of the waveform generating means 51 and the power supply of the amplifying means 52 are separated can be implemented. Also by these modified modes, substantially the same operational effects as those of the first embodiment can be obtained.

[In-vehicle device]
(Device Configuration of Example 2)
The “car seat temperature control device” as the second embodiment of the present invention is also an “in-vehicle temperature control device”. That is, as shown in FIG. 10, the temperature adjustment target of the Peltier element 1 included in the in-vehicle device of this embodiment is the seat surface and backrest of the car seat.

  As shown in FIG. 11, the in-vehicle device of the present embodiment includes a Peltier element 1 that switches and exhibits a cooling action and a heating action by a thermoelectric effect, a PMW drive apparatus 5 that drives the Peltier element 1, and a PMW drive apparatus 5. And a control device 4 for controlling. The control device 4 and the PWM drive device 5 are combined into one ECU, and this ECU receives power supplied from the in-vehicle DC power source connected to the battery 2 and appropriately drives the Peltier element 1 and the blower 6. . The control device 4 appropriately controls the PWM drive device 5 based on a signal from the operation device 3 having a switch or the like operated by an occupant and an external signal (not shown).

  As shown in FIGS. 10 and 11 again, the air A blown by the blower 6 is sent to the respective Peltier elements 1 from the blow ducts 60B and 60C divided into two hands, heated or cooled to an appropriate temperature, It is sent from the inside to the seat and back of the car seat. In addition, if the positive / negative of the drive voltage applied to the Peltier device 1 from the PWM drive device 5 is reversed by the control signal from the control device 4, the cold air C and the hot air W are reversed.

  Further, as shown in FIG. 12, the circuit configuration of the in-vehicle apparatus of the present embodiment is almost the same as the modified embodiment 2 of the first embodiment. However, the functions of the control device 4 and the waveform generating means 51 are increasing, and the state of the car audio (not shown) can be determined from the in-vehicle LAN signal, and the PWM frequency can be switched in two stages. That is, the control device 4 has a function of controlling the PWM drive device 5 to reduce the PWM frequency when a car audio AM radio receiver (not shown) is operating among various in-vehicle receiving devices. . Specifically, the waveform generating means 51 has a circuit configuration capable of generating a waveform by switching the frequency in two stages. The PWM frequency is normally 1 kHz, but is switched to 400 Hz when the AM receiver is operated.

(Effect of Example 2)
As a general trend, the amount of power that can be supplied by a vehicle such as an automobile is limited. Therefore, in-vehicle devices have more demands for power saving than devices that receive power from external power sources such as commercial power sources Is more compelling. In addition, in-vehicle devices are generally stricter than other devices in terms of device price, device weight, reliability, and the like.

  In that respect, since the on-vehicle device of the present embodiment has a high PWM frequency of the applied voltage generated by the PWM drive device 5, the Peltier device 1 can exhibit a high COP as described above in the section of the first embodiment. There is an effect that the operation efficiency of the entire system including the PMW driving device 5 is high. Therefore, according to the in-vehicle device of the present embodiment, the power saving effect is larger in the normal operation in which the effective voltage is relatively low and the operation is performed for a long time than the high output operation in a short time such as the start time. . Moreover, car seat temperature control devices are usually installed in high-end passenger cars, and in such vehicles, electrical components are frequently used and power consumption is large, and the power consumption is chronically insufficient. The effect is great.

  In addition, since the in-vehicle device of the present embodiment has the PWM driving device 5, the advantages of the PWM driving method are preserved, such as excellent device price, device weight and reliability.

  Furthermore, according to the vehicle-mounted device of the present embodiment, when the car radio AM radio receiver is operating, the PWM frequency of the PWM drive device is switched to a low value to reduce radio noise. There is an effect that noise is difficult to enter. The applicant already has a technique for reducing radio noise to a level that does not interfere with car audio at PWM frequencies up to about 20 kHz. However, if the PWM frequency is low, radio noise is less likely to occur. good.

  ・ Part 2: Characteristics chart and related technologies

[Characteristic chart]
(Configuration of Example 3)
The “Peltier element PWM drive characteristic chart” as Example 3 of the present invention is a chart showing the mutual relationship among the three parameters among the parameters related to the PWM drive characteristic of the Peltier element, as shown in FIG. 6 again. Here, the three parameters are the “PWM frequency” and “effective voltage” of the pulse-width-modulated driving voltage applied to the Peltier element, and “COP” indicating the operating efficiency of the Peltier effect exhibited by the Peltier element. "

  The characteristic chart (see FIG. 6) of this embodiment has the following two features. That is, the first feature is that it is a semilogarithmic graph, the vertical axis is a real number axis obtained by taking the COP exhibited by the Peltier element 1 (see FIG. 1), and the horizontal axis is PWM The logarithmic axis is obtained by dividing the frequency scale by logarithm. This determines the framework of the characteristic chart of the present embodiment. The second feature is that on the semilogarithmic graph, one oblique line segment M and one diagonal line each having a positive slope with respect to one predetermined value (for example, 2V or 8V) of the effective voltage. A broken line L having a horizontal line segment N continuous from the predetermined frequency M and having no inclination from a predetermined frequency is drawn.

  The bending point Ps of the broken line L seems to saturate the improved COP as the PWM frequency increases, so the inventors named it “COP saturation point” and named the PWM frequency as the saturation frequency Fs. It was. In addition, the saturation frequency Fs is a constant value (1 kHz) in common with any broken line regardless of the level of the applied voltage in the range of at least 2V to 8V. Further, the level of the COP at which the horizontal line segment N is located is COP (referred to as “DC COP”) Cd (about 2.8) when DC driving is performed with a DC voltage (2 V) of the same level as the effective voltage. equal.

  In other words, the characteristic chart of the present embodiment relates to the PWM drive characteristic when a drive voltage PWMed with a predetermined PWM frequency and duty ratio is applied to the Peltier element and the Peltier element exhibits a thermoelectric effect. It is a graph which shows the relationship between three among parameters. The characteristic chart of the present embodiment has the following three characteristics as shown in FIG.

  The first feature is a semi-logarithmic graph in which the PWM frequency of the drive voltage is taken on the logarithmic horizontal axis and the COP indicating the operation efficiency of the Peltier element is taken on the vertical axis. Next, the second feature is that the effective voltage of the drive voltage is fixed to two predetermined values (2V, 8V), and each of these predetermined values has a positive slope indicating the relationship between the PWM frequency and the COP. The diagonal line segment M is drawn in the low frequency region Bl of the saturation frequency Fs (1 kHz) or less. The third feature is that a polygonal line L having a horizontal line segment N and having a diagonal line segment M and a horizontal line segment N continuous at the saturation frequency Fs is drawn in a high frequency region Bh of the saturation frequency Fs or higher.

  In the characteristic chart of FIG. 6, only two lines, a broken line L when the effective voltage is 2V, and a broken line (no symbol) when the effective voltage is 8V are drawn in order to avoid making the drawing complicated. However, a broken line with an effective voltage of 4V or 6V falls between the two broken lines shown in the figure.

(Effect of Example 3)
In the characteristic chart of this embodiment, at a predetermined value (for example, 8 V) of the effective voltage applied to the Peltier element, the relationship between the PWM frequency and the COP exhibited by the Peltier element is one up to the saturation frequency Fs. It is represented in a semilogarithmic graph by a straight diagonal line segment L. Therefore, as shown in FIG. 6 as well, the PWM drive characteristics at a plurality of effective voltage levels can be shown very simply in the graph with the same number of diagonal line segments. Also, unlike the case where the characteristic becomes a curve as in the normal graph (see FIG. 3 and FIG. 4), the plotting can be performed by interpolating between the measurement points by the characteristic test or by extrapolating in reverse. It is really easy, and therefore there is no error due to the selection of the approximate curve.

  Therefore, if the characteristic chart of the present embodiment is used, first, there is an effect that the drawing is extremely easy as described in the fourth embodiment described later. Further, as will be described later in Example 5, the frequency characteristic test of the Peltier device PWM drive device is simplified, and the utility value is the same as the result of testing over a long time while greatly reducing the time required for the test. There is an effect that it is possible to provide certain test data. Moreover, although it is paradoxical, a characteristic chart (see FIG. 5) in which a plurality of diagonal line segments are drawn only in the low-frequency region is more complete when the characteristic chart (see FIG. 6) of the present embodiment effective up to the high-frequency region is completed. In addition, there is an effect that the drawing can be performed with a smaller number of measurement points. Further, as will be described later in Embodiment 6, if the characteristic chart of this embodiment is converted, a secondary characteristic chart necessary for designing a Peltier element PWM drive device can be easily drawn. is there.

(Modification 1 of Example 3)
As shown in FIG. 5 again, the characteristic chart as the modified embodiment 1 of the present embodiment is a semi-logarithmic graph similar to that of the above-described present embodiment (FIG. 6), but the low frequency whose PWM frequency is equal to or lower than the saturation frequency Fs. The third embodiment is different from the third embodiment in that it is only an area and has only a diagonal line segment M. Even in this modified mode, it can be used in the same manner as in Example 3 as long as it is used within the described range, and substantially the same operational effects are exhibited. Moreover, if it is considered that the technical data used for the design of the PWM drive device 5 and the like is the COP frequency characteristic up to the saturation frequency Fs, this modified embodiment has practicality comparable to that of the third embodiment.

[Drawing method]
(Configuration of Example 4)
The “Peltier device PWM drive characteristic chart drawing method” as the fourth embodiment of the present invention corresponds to the above-described third embodiment by performing a test for measuring the COP of the thermoelectric effect exhibited by the Peltier device driven by PWM. This is a method of drawing a Peltier element PWM drive characteristic chart (see FIG. 6).

  The COP measurement test performed by the drawing method of the present embodiment is performed using the test apparatus (see FIG. 1) described in the section of “Research history”. That is, in this test, a rectangular wave drive voltage having a predetermined effective voltage that is pulse-width modulated at a predetermined PWM frequency and duty ratio is applied to the Peltier element 1, and the COP of the Peltier effect exhibited by the Peltier element 1 is measured. .

  The feature of the drawing method of this embodiment is that the characteristic chart is drawn in two steps as follows.

  That is, first, as shown in FIGS. 13A to 13B, the first polygonal line L1 is drawn in a semilogarithmic graph, and the PWM frequency at the COP saturation point Ps of the polygonal line L1 is common to each effective voltage. The saturation frequency Fs is determined. Next, as shown in FIG. 13C, for other effective voltages, COP is measured in a PWM frequency region lower than the saturation frequency Fs, and one measurement point P3 is obtained. The diagonal line N2 passing through the measurement point P3 and the horizontal line N2 corresponding to the direct current COP (Cd2) of the direct current voltage equal to the effective voltage on the higher frequency side than the saturation frequency Fs are continuous broken lines at the saturation frequency Fs. Draw L2.

  More specifically, the first stage in the configuration of the drawing method of this embodiment is until the saturation frequency Fs is determined.

  First, as shown in FIG. 13A again, in PWM driving at a predetermined effective voltage (for example, 2 V), the first frequency F1 having a relatively low PWM frequency and the second frequency F2 having a relatively high frequency are described above. The COP measurement test is performed. Then, the COP measurement results at the first frequency F1 and the second frequency F2 are defined as a first COP (C1) and a second COP (C2), respectively. However, if the COP at the second frequency F2, that is, the second COP (C2) becomes approximately the same as the direct current COP (Cd), the second frequency F2 can be set lower than the saturation frequency Fs. Set the dual frequency F2 lower and re-measure. When the measurement result is obtained, the first measurement point P1 determined by the set first frequency F1 and the measured first COP (C1), the second frequency F1 and the second COP (C2) determined by the first measurement point P1. Two measurement points P2 are plotted on a semilogarithmic graph with the PWM frequency on the logarithmic horizontal axis and the COP on the vertical axis.

  Before and after this, a COP that is exhibited when a DC voltage equal to the effective voltage is applied to the Peltier element 1 is defined as a DC COP, and a broken line corresponding to the DC COP (Cd) is drawn on the semilogarithmic graph. . If the direct current COP (Cd) corresponding to the effective voltage is not obtained in advance, the COP measurement test may be performed by driving the Peltier element 1 with direct current.

  Next, as shown in FIG. 13B again, in this semilogarithmic graph, an oblique line segment M1 having a positive inclination including the first measurement point P1 and the second measurement point P2 in the middle is described above. Pull until the broken line of DC COP (Cd) is reached. Then, the point at which the diagonal line segment M1 reaches the broken line is defined as the COP saturation point Ps, and the horizontal line segment N1 is drawn to the high frequency side by overlapping the broken line with the COP saturation point Ps as the break point. That is, with the COP saturation point Ps as a boundary, an oblique line segment M1 is drawn on the low frequency side, a horizontal line segment N1 is drawn on the high frequency side, and a polygonal line L1 composed of the oblique line segment M1 and the horizontal line segment N1 is shown in a semilogarithmic graph. Draw on top.

  By doing so, since the COP saturation point Ps is determined as the break point of the broken line L1, the saturation frequency Fs can also be determined as shown in FIG. 13B. If the knowledge that the saturation frequency Fs is common even when the effective voltages are different levels is used, a line graph with the effective voltage at another predetermined level can be obtained by performing only one measurement as follows. Can be drawn easily.

  That is, the second stage of the construction of the drawing method of the present embodiment uses the saturation frequency Fs determined from the first broken line L1, and uses the second and subsequent broken lines L2,. This is the stage of drawing.

  That is, as shown in FIG. 13C again, in the high frequency region higher than the saturation frequency Fs, the horizontal line segment N2 determined by the direct current COP (Cd2) at the same level as the second effective voltage (for example, 4 V) is drawn. deep. Then, only one COP measurement test is performed for the effective voltage, the measurement point P3 is plotted on a semilogarithmic graph, and the diagonal line segment passes through the measurement point P3 to the COP saturation point Ps2 that is the start point of the horizontal line segment N2. Draw M2. Similarly, for the second and subsequent broken lines L2,..., One measurement point P3,... Is obtained for each predetermined level of the effective voltage, and the broken lines L2,.・ Draw a line.

  In the drawing method of this embodiment, the Peltier element PWM drive characteristic chart is completed as described above.

(Effect of Example 4)
In the drawing method of this embodiment, the duty ratio of the PWM drive voltage is made constant (that is, the effective voltage is made constant), and a test for measuring the PWM frequency characteristics of the COP exhibited by the Peltier device 1 is performed. To draw a characteristic chart.

  First, in the first stage, in order to draw the first polygonal line L1, two measurements P1 and P2 of COP measurement at the first frequency F1 and COP measurement at the second frequency F2 are performed. Simple. On the other hand, in the second stage, in order to draw the second and subsequent polygonal lines L2,..., Only one point (for example, only P3) needs to be measured for each level of the effective voltage. It is.

  Specifically, in order to plot FIG. 6, a measurement test was performed at 16 points. However, if FIG. 13C is plotted by the plotting method of this embodiment, only a measurement test is performed at three points. The number of test points is reduced to 1/5 or less. Such an effect of reducing the number of test points becomes more significant as the number of predetermined levels of effective voltage increases.

  Therefore, according to the drawing method of the present embodiment, the time required for the PWM frequency characteristic test for obtaining the COP of the Peltier element can be drastically shortened. In addition, there is an effect that a more complete characteristic chart that is effective up to a high frequency region exceeding the saturation frequency Fs of the Peltier element can be completed. Further, there is an effect that the saturation frequency Fs can be easily obtained.

(Modification 1 of Example 4)
As a variation 1 of the present embodiment, as shown in FIG. 5 with respect to FIG. 4 described above, a plurality of diagonal line segments are drawn instead of a plurality of line segments as long as the effective range of the line graph is limited to the PWM frequency equal to or lower than the saturation frequency Fs. There is also a method of drawing a characteristic chart. Also by this modification, the effect of reducing the number of measurement points according to the above-described embodiment can be obtained. However, since this modification requires two measurement points for each of the diagonal line segments, more measurement points are required than in the above-described embodiment.

[Test method]
(Configuration and effect of Example 5)
The “test method for determining the PWM drive characteristics of a Peltier element” as Example 5 of the present invention is characterized in that it is performed in accordance with the method for drawing the Peltier element PWM drive characteristic chart described in Example 4 above. .

  In the present embodiment, as already described in the section of the fourth embodiment, if the COP measurement test at the time of the Peltier element PWM drive is performed according to the procedure of the fourth embodiment, the number of measurement points of the Peltier element is much smaller than the conventional one. There is an effect that the PWM drive characteristic can be measured. In addition, according to the present embodiment, there is also an effect that a more complete characteristic chart in a high frequency region exceeding the saturation frequency Fs can be obtained while the measurement test time is dramatically shortened.

  It should be noted that as a variation 1 of the present embodiment, a test method performed in accordance with the procedure of the drawing method of the variation 1 of the fourth embodiment can be implemented. However, this modification is effective only for the characteristic chart in the PWM frequency region below the saturation frequency Fs, and more measurement points are required than the test method of the fifth embodiment.

[Usage: Secondary characteristics chart]
(Configuration of Example 6)
The “use method of the Peltier element PWM drive characteristic chart” as the sixth embodiment of the present invention is based on the PWM drive characteristic chart (FIG. 6) of the Peltier element corresponding to the above-described third embodiment. This is a method for drawing a secondary chart that is easy to use for designing a PWM drive device. That is, the characteristics of this embodiment are based on the characteristic chart shown in FIG. 6, wherein “secondary characteristics” are obtained by drawing curves for several PWM frequencies, with the duty ratio or effective voltage as the horizontal axis and COP as the vertical axis. “Chart” (corresponding to FIG. 3). The present embodiment is essentially a method for drawing such a secondary characteristic chart.

(Effect of Example 6)
In the characteristic chart utilization method of this embodiment, a secondary characteristic chart (FIG. 3) in which the characteristic is drawn in a curve for a predetermined PWM frequency with the COP of the Peltier element as the vertical axis and the duty ratio or effective voltage as the horizontal axis. can get. Such a secondary chart is suitable as a material for designing a PWM drive device in which the PWM frequency is kept at a predetermined value and the duty ratio (effective voltage) is changed to adjust the COP or output of the Peltier element.

  Since this secondary characteristic chart is obtained secondarily based on the characteristic chart drawn by the drawing method of Example 4, as already explained in the section of Example 4, it is based on a very small number of measurement points. And can be drawn in a short time. Moreover, since the above characteristic chart is a semi-logarithmic graph in which a plurality of diagonal lines or polygonal lines are drawn straight, even if the number of measurement points as a basis is small, it is based on the coordinate conversion to the secondary characteristic chart. You can get a lot of data with sufficient density. As a result, the curve group drawn on this secondary characteristic chart is smoother than the same type of graph created by taking many measurement points over a long period of time even if the number of test points is small. Is interpolated.

  Therefore, according to the characteristic chart utilization method (secondary characteristic chart drawing method) of the present embodiment, a secondary characteristic chart that is convenient for designing a PWM drive device of a Peltier element can be obtained by simply converting the characteristic chart. It is easy to obtain and has an effect that the curve group becomes smooth.

(Modification 1 of Example 6)
As a variation 1 of the present embodiment, a characteristic chart (corresponding to FIG. 5) drawn by the drawing method of the variation 1 of the fourth embodiment is converted to draw the above-mentioned secondary characteristic chart (corresponding to FIG. 3). The method of using the characteristic chart can also be implemented. Also according to this modified mode, an operational effect equivalent to that of the above-described sixth embodiment can be obtained.

[Usage: Design method]
(Configuration and effect of Example 7)
The “use method of the PWM drive characteristic chart” as the seventh embodiment of the present invention is based on the secondary characteristic chart (corresponding to FIG. 3) drawn as a result of the sixth embodiment or the modified embodiment 1 thereof. Alternatively, it is a design method for designing the PWM drive device (or method) according to the second embodiment or a modified example thereof.

  In this embodiment, as described in the sections of Embodiments 4 to 6, the secondary characteristic chart drawn based on data that can be prepared in a short-time measurement test is used as a document while taking advantage of the advantages of PWM drive. It is possible to design an apparatus capable of PWM driving a Peltier element with a high COP. Therefore, according to the method of using the characteristic chart of the present embodiment, there is an effect that the PWM drive device can be designed in a shorter time after a Peltier element having a new characteristic is developed. And if such an excellent product can be designed in a short time, it will be a great advantage in competitive fields such as automobiles in order to gain an advantage in the competition among the mounting equipment manufacturers.

Schematic diagram showing the configuration of a test apparatus that measures the PWM drive characteristics of a Peltier element (A) Graph showing a case where the applied voltage of the DC drive is slightly high (b) Graph showing a case where the applied voltage of the DC drive is slightly low (c) PWM drive (D) A graph showing a waveform when the effective voltage of PWM drive is slightly low The graph which shows the measurement result of the PWM drive characteristic test of the Peltier device Graph showing the relationship between PWM frequency and COP A semi-logarithmic graph showing the relationship between the PWM frequency and COP of the test result (Characteristic chart as modification 1 of embodiment 3) A semi-logarithmic graph obtained by adding additional data in the high frequency region to the test result (Characteristic chart as Example 3) The circuit diagram which shows the structure of the PWM drive device as Example 1 The circuit diagram which shows the apparatus structure as the deformation | transformation aspect 1 of Example 1. FIG. The circuit diagram which shows the apparatus structure as the deformation | transformation aspect 2 of Example 1. FIG. The schematic diagram which shows the structure of the seat provided with the car seat temperature control apparatus of Example 2. FIG. The schematic diagram which shows the structure of the car seat temperature control apparatus as Example 2. FIG. The circuit diagram which shows the structure of the car seat temperature control apparatus as Example 2. (A) Line graph showing DC COP and two measurement points (b) Line graph in which the first line is drawn (c) The second line is also drawn Line chart

Explanation of symbols

1: Peltier element 2: Battery (as DC power supply) 2A: Commercial power supply 3: Operating device ECU: On-vehicle electronic control unit 4: Control device 5: PWM drive device 51: Waveform generating means 52: Amplifying means 6: Blower 60: Air duct 61: Cold air duct 62: Hot air duct A: Incoming air C: Cold air W: Hot air Cd, Cd1, Cd2: DC COP
Fs: saturation frequency Ps: COP saturation point F1: first frequency C1: first COP P1: first measurement point F2: second frequency C2: second COP P2: second measurement point P3: third measurement points L, L1 , L2: broken line M, M1, M2: diagonal line segment N, N1, N2: horizontal line segment

Claims (19)

In a driving method of a Peltier element in which a drive voltage that is PWM (pulse width modulated) with a predetermined PWM frequency and duty ratio is applied to the Peltier element, and the Peltier element exhibits a thermoelectric effect,
The PWM frequency is 100 Hz or more,
PMW driving method of Peltier element. The PWM frequency is 400 Hz or more.
The PMW driving method for a Peltier device according to claim 1. The PWM frequency is 1 kHz or more.
The PMW driving method for a Peltier device according to claim 1. In a drive device for a Peltier element that is supplied with electric power from a predetermined power source and applies a drive voltage PWM (pulse width modulated) at a predetermined PWM frequency and duty ratio to the Peltier element, thereby causing the Peltier element to exert a thermoelectric effect ,
The PWM frequency is 100 Hz or more,
Peltier device PWM drive device. The PWM frequency is 400 Hz or more.
The PMW drive device for a Peltier element according to claim 4. The PWM frequency is 1 kHz or more.
The PMW drive device for a Peltier element according to claim 4. The power source is a DC power source,
The driving device includes waveform generating means for generating a predetermined rectangular wave voltage according to a predetermined control signal, and amplification means for amplifying the rectangular wave voltage and applying the driving voltage to the Peltier element.
The PMW drive device for a Peltier element according to claim 4. A Peltier element that performs at least one of cooling and heating by the thermoelectric effect;
The PMW drive device according to claim 4, wherein the Peltier element is PWM driven.
A control device for controlling the PMW drive device;
A vehicle-mounted temperature control device comprising: The control device has a function of controlling the PWM drive device to reduce the PWM frequency when a predetermined one of the in-vehicle reception devices is operating.
The on-vehicle temperature control device according to claim 8. The temperature adjustment target of the Peltier element is at least one of a seat surface and a backrest of a car seat,
The car seat temperature control apparatus which is a vehicle-mounted temperature control apparatus described in Claim 8. When a drive voltage PWM (pulse width modulated) with a predetermined PWM frequency and duty ratio is applied to the Peltier element and the Peltier element exhibits a thermoelectric effect, various parameters relating to the PWM drive characteristics of the Peltier element are set. home,
Taking the PWM frequency of the drive voltage on the logarithmic horizontal axis,
Taking the COP indicating the operating efficiency of the Peltier element on the vertical axis,
Either one of the duty ratio and the effective voltage of the driving voltage is fixed to at least one predetermined value;
Each of the predetermined values is a semi-logarithmic graph in which an oblique line segment having a positive slope indicating the relationship between the PWM frequency and the COP is drawn.
Peltier element PWM drive characteristic chart. In the region where the PWM frequency is equal to or lower than a predetermined frequency, the diagonal line segment is included.
It has a horizontal segment in the region above this predetermined frequency,
A broken line in which the diagonal line segment and the horizontal line segment are continuous at the predetermined frequency is drawn at least one,
The Peltier device PWM drive characteristic chart according to claim 11. A test for measuring the COP of the thermoelectric effect exerted by the Peltier element by applying a rectangular-wave drive voltage having a predetermined effective voltage, pulse-width modulated at a predetermined PWM frequency and duty ratio, to the Peltier element.
Perform for a first frequency that is a relatively low PWM frequency and a second frequency that is a relatively high PWM frequency,
The measurement results of the COP at the first frequency and the second frequency are defined as a first COP and a second COP, respectively.
The first measurement point determined by the first frequency and the first COP and the second measurement point determined by the second frequency and the second COP are plotted with the PWM frequency on the logarithmic horizontal axis and the COP on the vertical axis. Plot it on a semilogarithmic graph,
12. A Peltier device PWM drive characteristic chart according to claim 11, wherein an oblique line segment having a positive slope including the first measurement point and the second measurement point in the middle or at an end thereof is drawn on the semilogarithmic graph. It is characterized by drawing
Drawing method of Peltier device PWM drive characteristic chart. When a DC voltage equal to the effective voltage is applied to the Peltier element, a COP exerted by the Peltier element is defined as a DC COP, and a horizontal line segment corresponding to the DC COP is drawn to a higher frequency side than the oblique line segment,
The point where the diagonal line segment and the horizontal line segment intersect is defined as the COP saturation point at the effective voltage,
At least one polygonal line in which the diagonal line segment and the horizontal line segment are continuous at the COP saturation point is drawn.
A method for drawing a Peltier element PWM drive characteristic chart according to claim 13. At least one of the polygonal lines is drawn on the semilogarithmic graph, and the PWM frequency at the COP saturation point of the polygonal lines is determined as a saturation frequency common to the effective voltages,
For other effective voltages, the COP is measured in the PWM frequency region lower than the saturation frequency to obtain at least one measurement point. The diagonal line passing through the measurement point and the higher frequency side than the saturation frequency A horizontal line corresponding to a DC voltage equal to the effective voltage draws a continuous line at this saturation frequency.
A method for drawing a Peltier element PWM drive characteristic chart according to claim 14. It is performed in accordance with a method for drawing a Peltier element PWM drive characteristic chart according to any one of claims 13 to 15.
Peltier device PWM drive characteristics test method. Based on the PWM drive characteristic chart of the Peltier element described in claim 11
Plotting a secondary characteristic chart in which one of the duty ratio and the effective voltage is plotted on the horizontal axis, the COP is plotted on the vertical axis, and a curve is drawn for each of at least one predetermined value in the PWM frequency range. Features
How to use the PWM drive characteristic chart. The device according to any one of claims 4 to 10 is designed based on the secondary characteristic chart according to claim 17.
How to use the PWM drive characteristic chart. Among the parameters related to the PWM drive characteristics of the Peltier element, the “PWM frequency” and “duty ratio” of the pulse-width-modulated drive voltage applied to the Peltier element and the operation efficiency of the Peltier effect exhibited by the Peltier element are shown. In the chart showing the three-way relationship with “COP”,
The vertical axis of the chart is a real axis of the COP, the horizontal axis of the chart is a logarithmic axis of the PWM frequency, and the chart is a semi-logarithmic graph;
On this semi-logarithmic graph, there is one diagonal line segment having a positive slope for each predetermined value of the duty ratio, and a horizontal line segment that is continuous to the diagonal line segment and has no slope from the predetermined frequency. Among the polygonal lines, at least the former is drawn,
Peltier element PWM drive characteristic chart.

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