JP2007206006A - Transformer measuring method, evaluation facilities, and transformer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and quickly measure the total loss, including a primary winding and a secondary winding by simultaneously supplying currents to the primary-side winding and the secondary-side winding for precisely measuring the loss of a transformer. <P>SOLUTION: The secondary-side terminal of the transformer is short-circuited and the loss resistance component is measured from the primary-side so that the total loss including the primary-side winding and the secondary winding can be measured. In the actual condition that achieves skin effect and proximity effect, it can be used as evaluation facilities or inspection facilities, since it is simple and quick, and the transformers allowing precise and simple comparison are achieved, when described in catalogs or specifications. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transformer, particularly a transformer for a switching power supply.

  Transformers are often used for electronic devices. In particular, a switching power supply often uses a transformer that operates at a high frequency. In a switching power supply corresponding to the recent low voltage and large current of electronic circuits, the heat generation of the transformer may be a problem due to the large current. Here, there is a case where it is desired to make or select a high-quality transformer with low heat generation. Heat generation is also called loss, and there are cases where it is desired to effectively evaluate the loss of the transformer. However, since the heat generation mechanism of the transformer is complicated and the winding loss is complicated by the skin effect and proximity effect, various techniques have been devised for obtaining the heat generation amount or the winding loss.

  The first example of the prior art is described in "New Measurement Methods to Characterize Transformer Core Loss and Copper Loss In High Frequency Switching Mode Power Supplies." This is a method of calculating a loss by applying a high-power pulse waveform similar to the condition to the transformer, measuring the voltage and current waveforms. This method can accurately measure the loss of the transformer, but the transformer requires processing, takes time, cannot be applied to product inspection, has a large facility, and has a complicated calculation process. is there.

  The second example of the prior art is described in “Electrical Terminal Representation of Conductor Loss in Transformers”. The impedance component is measured from the input terminal and the output terminal respectively, and the resistance component becomes a loss at an arbitrary frequency. Is a method of measuring. This method is convenient because the measurement is simple and can be performed quickly.

  FIG. 5 shows an embodiment of the prior art. The transformer 1 is the object to be measured, and the measuring machine 2 is connected to the terminal 11 of the primary winding. The measuring device 2 is supplied with a signal using an LCR meter or the like to measure the loss resistance. At this time, nothing is connected to the terminal 12 of the secondary winding and it is left open. Thus, the loss resistance of the primary winding can be measured. If the same measurement is performed with the secondary winding replaced, the loss resistance of the secondary winding can be measured.

  This method is convenient because it is simple and can be carried out quickly. When measuring the loss from the primary side, the current is supplied only to the primary winding, and when measuring the loss from the secondary side, the current is supplied only to the secondary winding. Therefore, there is a problem that the proximity effect, which is the interaction between the primary winding and the secondary winding, is eliminated and an error corresponding to the proximity effect occurs.

Y. Han, W. Eberle, Y. Liu, "New Measurement Methods to Characterize Transformer Core Loss and Copper Loss In High Frequency Switching Mode Power Supplies." IEEE Power Electronics Specialists Conference, 2004 James H. Spreen, "Electrical Terminal Representation of Conductor Loss in Transformers" IEEE trans. On Power Electronics, Vol. 5, No. 4, October 1990

  The winding structure of transformers in recent years is no longer a simple structure using conventional wire rods, such as the use of copper plates or ring-shaped plates, skin effects, proximity effects, primary / secondary winding interactions, etc. In such a case, there is a case where it is desired to measure the loss of the transformer sufficiently accurately industrially. That is, there is a case where it is desired to measure the loss while simultaneously passing current through the primary and secondary windings. In addition, in response to recent short-term development, there is a case where it is desired to make a simple measurement without preparing complicated and large-scale equipment or performing additional processing such as adding an auxiliary winding to the transformer. If simple and accurate measurement is possible, comparison of different types of transformers will be simple and accurate, design and production of high-quality power supplies will be possible, and evaluation and inspection will be simple and accurate.

  The problem to be solved by the present invention is to realize sufficiently accurate loss measurement by a simple method. More specifically, a simple method is used to measure the loss performed while simultaneously passing current through the primary and secondary windings.

  In order to measure the loss while simultaneously passing current through the primary winding and the secondary winding, a means for short-circuiting the terminal of the secondary (or primary) winding is prepared, and the primary (or secondary) is prepared. A means for measuring the resistance component from the terminal of the winding is prepared. In this way, the measurement while the current is simultaneously supplied to the primary winding and the secondary winding is realized due to the nature of the transformer. As a result, it is possible to measure or evaluate the total loss, not the primary winding and the secondary winding, respectively. Further, it is possible to measure or evaluate the total loss including the primary winding and the secondary winding in consideration of other losses such as core loss as required.

  According to the present invention, there is an effect that the total loss including the primary winding and the secondary winding can be measured and evaluated.

  Hereinafter, the present invention will be described in detail with reference to examples.

  FIG. 1 shows a first embodiment of the present invention.

  The short-circuit piece 3 is connected to the terminal 12 of the secondary winding of the transformer 1 to be measured. The measuring machine 2 is connected to the terminal 11 of the primary winding, and a signal is given to the measuring machine 2 using an LCR meter or the like to measure the loss resistance. The signal given by the measuring machine 2 causes a current to flow through the primary winding, and since the terminal of the secondary winding is short-circuited, a current also flows through the secondary winding due to the nature of the transformer. In this way, measurement is performed while simultaneously passing current through the primary winding and the secondary winding. Therefore, the measurement is performed in a state where the proximity effect between the primary and secondary windings and the interaction such as the capacitance are added. Further, the resistance component measured by the measuring machine 2 is mainly the total loss of the primary winding and the secondary winding.

  As described above, in the first embodiment of the present invention, the total loss including the primary winding and the secondary winding can be measured and evaluated.

  The loss may be expressed in an appropriate form such as power, energy amount, and resistance value. Using an LCR meter, the resistance value of the loss can be measured directly, but the resistance value of the loss is a normalized expression that does not depend on voltage or current, and is a convenient way to express the loss.

  Moreover, since the names of the primary and secondary windings are artificial, the numbers may be interchanged. The same applies when there are more than two windings. In the present invention, the terminal of the winding connected to the measuring instrument is called the primary side, and the terminal of the other winding is called the secondary side.

  If there are more than two windings, a method such as shorting all but the primary winding or shorting a desired winding may be employed.

  FIG. 2 shows a second embodiment of the present invention.

  2 is different from FIG. 1 in that the measurement configuration is such that the primary winding and the secondary winding of the transformer 1 are interchanged. Accordingly, the short-circuit piece 3 is connected to the terminal 11 of the primary winding of the transformer 1, and the measuring machine 2 is connected to the terminal 12 of the secondary winding. The resistance component measured by the measuring machine 2 is mainly the total loss of the primary winding and the secondary winding. Since the measured value becomes the secondary winding conversion value, if necessary, it can be converted into the primary winding conversion value using the turns ratio of the primary winding and the secondary winding of the transformer.

  Even in this configuration, the total loss including the primary winding and the secondary winding can be measured and evaluated as in the first embodiment.

  The configuration shown in FIG. 1 and the configuration shown in FIG. 2 may be measured by selecting a convenient one depending on the shape and properties of the transformer.

  If it is desired to take into account the core loss of the transformer, as shown in FIG. 3, the secondary winding of the transformer 1 is opened and the signal source 4 is connected to the terminal 11 of the primary winding. The loss of the core of the transformer can be measured by applying the above signal. Therefore, the core loss may be added to the total loss of the primary winding and the secondary winding described above to newly call the total loss of the primary winding and the secondary winding, or the total of the transformer. It may be called loss, total loss, etc. Since the core loss is often smaller than the winding loss, it can be omitted and referred to as the total loss, and the total loss of the primary and secondary windings is referred to as the total loss. You can call it. Therefore, in the present invention, if the loss of the primary winding and the secondary winding is included, the total loss including the primary winding and the secondary winding regardless of whether other losses are included or not. Say.

  In addition, any of the above measurements can be performed at an arbitrary frequency. If a pulse wave is input, it is possible to measure resistance or loss with respect to a pulse waveform having an arbitrary waveform. The pulse waveform has a fundamental wave component and a harmonic component, but if the loss is measured with a sine wave and multiplied by a coefficient of about 1 to 3, the harmonic component is taken into consideration. Loss values can be obtained.

  The third embodiment is an evaluation facility according to the present invention, and uses the above-described measuring method according to the present invention. The measurement method of the present invention is suitable for evaluation equipment because it does not process the transformer to be measured. Obviously, the evaluation equipment can also be used for inspection and includes inspection equipment.

  FIG. 4 shows the configuration of the evaluation facility according to the present invention. Transformer 1 is the subject of evaluation. The evaluation facility includes a measuring machine 2, a short-circuit mechanism 31, a desorption mechanism 5, and a control / determination mechanism 6. The short-circuit mechanism 31 short-circuits the terminal of the secondary winding of the transformer 1, and the measuring machine 2 measures the loss. The desorption mechanism 5 is a mechanism for desorbing a transformer to be evaluated. The control / determination mechanism 6 controls a measuring machine, a desorption mechanism, etc., determines an evaluation result, and records a measurement value. Any of them may be provided or excluded as necessary, or provided with necessary functions, and is a part of evaluation equipment.

  In the third embodiment, the total loss including the primary winding and the secondary winding can be evaluated and inspected by the measuring method of the present invention.

  Although not shown, the fourth embodiment is a transformer that clearly shows the total loss including the primary winding and the secondary winding. If the loss value measured by the above method or the evaluation facility is specified, the performance of the transformer can be compared. There are various methods to specify the total loss including the primary and secondary windings. There are various methods, but the method described in the transformer itself, the method described in the catalog, the method described in the data sheet, the test result table And a method described in various specifications such as a purchase specification.

  If the total loss of the primary and secondary windings of the transformer is specified, it is beneficial to quickly compare the performance of the transformer. In particular, if it is specified in the catalog or data sheet, it will be possible to study and compare on the desk, avoid the waste of obtaining and evaluating samples, and the measurement method according to the present invention is accurate, so it actually assembles a switching power supply etc. Therefore, the waste of evaluating the loss of the transformer is blown away.

  The name used in the description may be selected as appropriate. Total loss including primary winding and secondary winding, total loss of primary winding and secondary winding, total loss, total loss chamber, AC loss If the loss of the primary winding and the secondary winding is included, it is said to be the total loss including the primary winding and the secondary winding.

  As described above, in the fourth embodiment of the present invention, the total loss including the primary winding and the secondary winding can be easily evaluated.

  The measuring method according to the present invention can be widely used in general for transformers, especially transformers for switching power supplies. Moreover, the evaluation equipment according to the present invention can be widely used for transformer evaluation and inspection.

The figure of a 1st Example. The figure of a 2nd Example. Figure of measurement of transformer core loss. The figure of a 3rd Example. The figure of the Example of a prior art.

Explanation of symbols

1 transformer
11 Primary winding terminal
12 Secondary winding terminal
2 Measuring machine
3 Shorting piece
31 Short-circuit mechanism
4 Signal source
5 Desorption mechanism
6 Control / judgment mechanism

Claims (8)

  A transformer measuring method, characterized in that in measuring the loss of a transformer, the secondary side terminal of the transformer is short-circuited and the loss is measured from the primary side terminal of the transformer.   A transformer evaluation facility, comprising: a short-circuit means for short-circuiting a secondary terminal of the transformer, and a measuring device for measuring a loss from the primary terminal of the transformer.   Transformer characterized by total loss including primary and secondary windings.   A transformer using the transformer measurement method according to claim 1.   A transformer characterized in that the transformer evaluation facility according to claim 2 is used.   3. The transformer evaluation facility according to claim 2, further comprising a desorption mechanism for desorbing the transformer.   The transformer evaluation facility according to claim 2, further comprising a control / determination mechanism that controls the measuring machine and determines a measurement result. 4. The transformer according to claim 3, wherein the loss includes a loss of a core of the transformer.

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