JP2910277B2 - Converter transformer inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a converter transformer inspection apparatus used for consumer or industrial electronic equipment.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventional converter transformer inspection apparatus. In FIG. 9, 1 is a converter transformer to be inspected, 2 is a sine wave oscillator, 3
Is a primary winding applied voltage measuring device, and 4 is a secondary winding output voltage measuring device, which applies the output of the sine wave oscillator 2 to the primary winding of the converter transformer 1 to be inspected.
Is connected in parallel with the primary winding, and the output voltage of the secondary winding of the converter transformer under test 1 is connected to the secondary winding output voltage measuring instrument 4.

In FIG. 10, reference numeral 5 denotes an AC power supply, 6 denotes a mounting set for actually using the converter transformer 1 to be inspected, and 7 denotes a load device for consuming a load actually supplied by the mounting set 6. Converter transformer 1
Is connected to the mounting set 6, the output of the AC power supply 5 is applied to the input of the mounting set 6, and the output of the mounting set 6 is applied to the load device 7.

[0004] The operation of the converter transformer inspection apparatus configured as described above will be described below. First, as a converter transformer inspection device, as shown in FIG. 9, an applied voltage of a primary winding is measured by a primary winding applied voltage measuring device 3, and a converter transformer 1 to be inspected is measured.
The output voltage of the secondary winding is measured by the secondary winding output voltage measuring device 4 to check the disconnection of the converter transformer 1 for inspection based on the presence or absence of the secondary winding output voltage, and to check the secondary winding output voltage and The operation of the converter transformer is assured by taking the ratio of the primary winding applied voltage and managing this voltage ratio.

[0005] As shown in FIG. 10, the mounting set 6 is operated to check the presence or absence of a voltage applied to the load device 7 to check for a break in the converter transformer 1 to be inspected, and to determine a voltage value applied to the load device 7. The operation of the converter transformer was guaranteed by managing the

[0006]

In FIG. 9 having such a conventional structure, the voltage applied to the primary winding is a pulse waveform of a high voltage of 80 to 1000 V in the actual operation of the converter transformer, and the iron core of the converter transformer is used. Although the maximum magnetic flux density generated is 1000 to 3000 gauss, the maximum magnetic flux density is 10 gauss or less with a low voltage sine wave of 1 V or less, and the load of the secondary winding is not consumed. Since a certain power conversion is not performed, the condition under which the converter transformer 1 under test actually operates is very different, and a change in the output voltage of the winding due to a subtle change in the winding of the converter transformer cannot be detected.

In FIG. 10, the output voltage can be inspected because the inspection is performed by the mounting set 6. However, since the protection circuit for the abnormal converter transformer is not provided, the abnormal converter transformer is detected during the inspection. In addition, it takes time to repair the circuit because the circuit of the mounting set 6 itself is destroyed due to a contact failure when the converter transformer is connected to the mounting set 6, and the mounting set 6 is required for each converter transformer 1 to be inspected. However, there is a problem that automation of the system is very difficult.

The present invention solves the above-mentioned conventional problems, and provides a converter transformer inspection apparatus which can be operated in a state close to the actual operation of the converter transformer to be inspected and which can cope with abnormal converter transformers. The purpose is to provide.

[0009]

In order to achieve the above object, a converter transformer inspection apparatus according to the present invention connects a primary winding of a converter transformer to be inspected to a DC power supply via a switching element. And a primary winding current detection circuit is provided in series with the switching element, an overvoltage protection circuit is connected to the switching element application voltage detection circuit, and an overvoltage protection circuit is connected to the primary winding current detection circuit. A current protection circuit is connected, a load device is connected to the secondary winding of the converter transformer to be tested via an output circuit, and the output of the load device is applied to a judgment circuit, and the overvoltage protection circuit and the overcurrent protection circuit are connected. The output is applied to a pulse generation circuit whose frequency and duty ratio can be set.

[0010]

With this configuration, a high-voltage pulse waveform is applied to the primary winding of the converter transformer to generate a maximum magnetic flux density of 1000 gauss or more in the iron core of the converter transformer, and a load is consumed from the secondary winding to cause the converter transformer to consume a load. Can be operated and inspected in a state close to the actual operation of the converter transformer, the inspection device can be protected by a protective operation against abnormal converter transformers and the like, and abnormal products can be detected.

[0011]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
5 shows a converter transformer inspection apparatus in the embodiment of FIG. In FIG. 1, 11 is a converter transformer to be inspected, 12 is a DC power supply, 13 is a switching element, 14 is a switching element applied voltage detection circuit, 15 is a primary winding current detection circuit, 16 is an overvoltage protection circuit, and 17 is overcurrent protection. Circuit, 18 is a pulse generation circuit that can set the frequency and duty ratio, 19 is an output circuit, 20 is a load device, 21 is a judgment circuit, 22 is a primary winding, and 23 is a secondary winding.

That is, the primary winding 22 of the converter transformer 11 to be inspected is connected to the DC power supply 12 via the switching element 13, and a switching element applied voltage detecting circuit 14 is provided in parallel with the switching element 13. 13, a primary winding current detection circuit 15 is provided in series, an overvoltage protection circuit 16 is connected to the switching element applied voltage detection circuit 14, and an overcurrent protection circuit 17 is connected to the primary winding current detection circuit 15. Secondary winding 23 of converter converter 11 for inspection
Is connected to a load circuit 20 via an output circuit 19, the output of the load circuit 20 is applied to the determination circuit 21, and the outputs of the overvoltage protection circuit 16 and the overcurrent protection circuit 17 are applied to the pulse generation circuit 18. Make up.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. First, the operation of the protection circuit will be described.
FIG. 2A shows the switching element applied voltage waveform 31 of the part a in FIG. 1. This voltage waveform is detected by the switching element applied voltage detection circuit 14, and the peak voltage of the j part of the switching element applied voltage waveform 31 is overvoltage protected. If the voltage value of the part j is higher than the value set by the circuit 16, the protection signal is sent to the pulse generation circuit 18 to stop the generation of the pulse and the switching element 13 is protected from overvoltage.

FIG. 2 (b) shows a primary winding current waveform 32 of a portion c in FIG. 1, and this current waveform is detected by a primary winding current detection circuit 15 to detect a k portion of the primary winding current waveform 32. The peak current is compared with a value set by the overcurrent protection circuit 17.
To stop the generation of a pulse to protect the switching element 13 from overcurrent. Here, when the secondary winding 23 of the converter transformer 11 to be inspected is disconnected, the peak voltage at the j portion of the switching element applied voltage waveform 31 in FIG. 2A is significantly increased, and the overvoltage protection operation is performed.

The converter transformer 11 to be inspected
When the secondary winding 23 is short-circuited, the peak current in the k portion of the primary winding current waveform 32 in FIG. 2B is significantly increased, and the overcurrent protection operation is performed.

Next, a method of inspecting the converter transformer will be described. FIG. 2C shows the primary winding voltage waveform 33 of the portion d in FIG. 1, the voltage value of the m portion becomes the output voltage V _IN of the DC power supply 12, and the voltage value V _{FB of the} portion becomes the following equation.

[0017]

(Equation 1)

FIG. 2D shows the secondary winding voltage waveform 34 in the section e in FIG. 1 and the voltage value V _SFB in the n section and the voltage value V _{SFF in the} o section are given by the following equations.

[0019]

(Equation 2)

The secondary side voltage waveform 34 in the section e is rectified and smoothed by the output circuit 19 to generate a DC voltage V _{O in the} section f. This voltage is applied to the load device 20 to consume the load. Circuit for the output circuit 19 is generally flyback, choke input type, the capacitor is input system such as a DC voltage V _O of f part in each method has different, V _O at any output circuit system of the above When the duty ratio of the pulse generation circuit 18 becomes constant, the voltage becomes proportional to the voltage of the n or o part of the secondary winding voltage waveform 34 of the e part, and the DC voltage value V _o of the f part can be expressed by the following equation. .

[0021]

(Equation 3)

In equation (3), K _S , N _P , and N _S are constants determined by the structure of the converter transformer 11 to be inspected, and especially K _S fluctuates due to variations in winding of the winding. Therefore, the operation of the converter transformer can be guaranteed by managing the DC voltage of the f section. In this circuit example, the inspection is performed by detecting the DC voltage of the f section by the load device 20 and applying the detected voltage to the determination circuit 21 for determination.

As described above, according to this embodiment, a high-voltage pulse waveform is applied to the primary winding 22 of the converter transformer 11 to be inspected, the load is consumed from the secondary winding 23, and the actual operation of the converter transformer is performed. To realize an excellent converter transformer inspection device that can be operated and inspected in a close state, and protects the inspection device by the protection operation even for abnormal converter transformer products and can detect abnormal products. Can be.

(Embodiment 2) Hereinafter, another embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a block diagram of a primary winding peak current detection block of a converter transformer inspection apparatus according to a second embodiment of the present invention. In FIG. 3, reference numeral 15 denotes a primary winding current detection circuit of the converter transformer inspection device according to the first embodiment, 17 denotes an overcurrent protection circuit of the converter transformer inspection device, and 21 denotes a judgment of the converter transformer inspection device. A circuit 35 is a peak detection circuit, which is configured so that the output of the primary winding current detection circuit 15 is connected to the peak detection circuit 35 and the output of the peak detection circuit 35 is applied to the determination circuit 21.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. FIG. 2B is a diagram showing the first embodiment shown in FIG.
In the primary winding current waveform 32 in the section, the primary winding peak current value of the k section of the primary winding current waveform 32 is detected by the peak detection circuit 35 via the primary winding current detection circuit 15 in FIG. The primary winding peak current value is determined by the determination circuit 21. The value of the k part detected in this configuration is as follows.

[0026]

(Equation 4)

In equation (4), frequency F, duty ratio
δ, voltage V of DC power supply 12_INCan be fixed and the first fruit
The converter transformer to be inspected by the inspection in the embodiment
The number of turns N of the primary winding 22_PIs constant and the coupling coefficient
K_SIs within the standard, P _INIs set by the load device 20
And the peak value of the k part is
The characteristics of the iron core used for the converter transformer 11
A certain inductance coefficient A_LChange only by
Therefore, the primary winding peak current shown in FIG.
By adding the detection block, the inspection of the first embodiment can be performed.
At the same time, it is used for the converter
Inspection of the characteristics of the iron core can be realized.

Embodiment 3 Another embodiment of the present invention will be described below with reference to the drawings. FIG. 4 shows a block diagram of a switching element applied peak voltage detection block of a converter transformer inspection apparatus according to a third embodiment of the present invention.

In FIG. 4, reference numeral 14 denotes a switching element applied voltage detection circuit of the converter transformer inspection device constructed in the first embodiment, 16 denotes an overvoltage protection circuit of the converter transformer inspection device, and 21 denotes the converter transformer inspection. A determination circuit 36 of the device is a peak detection circuit, which is configured so that the output of the switching element applied voltage detection circuit 14 is connected to the peak detection circuit 36 and the output of the peak detection circuit 36 is applied to the determination circuit 21.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. 1 to 2 and FIG. FIG. 2A shows a voltage waveform 31 applied to the switching element in the part a of FIG. 1 shown in the first embodiment.
Then, the peak voltage value of the switching element applied voltage at the j part of the switching element applied voltage waveform 31 is detected by the peak detection circuit 36 via the switching element applied voltage detection circuit 14 of FIG. The value is determined by the determination circuit 21. In this configuration, the value of the j-part V _DSP detected in this configuration is determined by setting the leakage inductance of the converter transformer under test 11 to L _LEAK.
Then

[0031]

(Equation 5)

The peak value V _DSP2 of the voltage applied to the switching element 13 when the converter transformer 11 to be inspected is used in a mounting set is also obtained.

[0033]

(Equation 6)

[0034] a and, therefore V _DSP and V _{DSP 2} is the leakage inductance L of the V _{DS P2} inspection simultaneously with inspection for converter transformer 11 of Example 1 it is possible to restrict by managing V _DSP becomes proportional _LEAK
As a result, it is possible to realize whether or not the switching element 13 may be destroyed beyond the maximum rating of the switching element 13 when used in a mounting set due to the increase in V _DSP2 .

(Embodiment 4) Another embodiment of the present invention will be described below with reference to the drawings. FIG. 5 shows a configuration diagram of a switching voltage detection block of a converter transformer inspection device according to a fourth embodiment of the present invention. In FIG. 5, reference numeral 14 denotes a switching element applied voltage detection circuit of the converter transformer inspection device according to the first embodiment, 16 denotes an overvoltage protection circuit of the converter transformer inspection device, and 21 denotes a judgment circuit of the converter transformer inspection device. , 37 are low-pass filters, and 38 is a peak detection circuit. A peak detection circuit 38 is connected to the output of the switching element applied voltage detection circuit 14 via a low-pass filter 37, and the output of the peak detection circuit 38 is applied to the determination circuit 21. It is configured to be.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. 1 to 2 and FIG. FIG. 2A shows a voltage waveform 31 applied to the switching element in the part a of FIG. 1 shown in the first embodiment.
The switching element applied voltage value of the i-portion of the switching element applied voltage waveform 31 is the low-pass filter 3 shown in FIG.
7, is detected by the peak detection circuit 38, and the voltage applied to the switching element is determined by the determination circuit 21. Here, the switching element applied voltage value V _DS of the i part is
Is

[0037]

(Equation 7)

If the performance of the DC power supply 12 is guaranteed, V _IN is constant, and the voltage V _DS applied to the switching element in the i section is determined only by the duty ratio.

However, the duty ratio is generated by the pulse generation circuit 18 shown in FIG. 1, and the actual applied voltage waveform 31 of the switching element 13 changes due to the variation in the switching speed characteristic of the switching element 13. it has test of example 1 may not be performed normally, but can guarantee the operation of the inspection apparatus itself converter transformer by managing the switching element application voltage value V _DS of the i section Thus, the accuracy of the inspection of the first embodiment can be improved.

Embodiment 5 Hereinafter, still another embodiment of the present invention will be described with reference to the drawings. FIG. 6 shows a configuration diagram of a leakage flux detection block of a converter transformer inspection apparatus according to a fifth embodiment of the present invention. In FIG. 6, reference numeral 11 denotes a converter transformer to be inspected of the converter transformer inspection apparatus according to the first embodiment, 21 denotes a determination circuit, 39 denotes a magnetic sensor,
Numeral 40 denotes a sensor voltage detection circuit, in which the magnetic sensor 39 is arranged close to the converter transformer 11 to be inspected, the magnetic sensor 39 is connected to the sensor voltage detection circuit 40, and the output of the sensor voltage detection circuit 40 is determined by a judgment circuit. 21 is applied.

FIG. 7A shows an arrangement of the magnetic sensor 39 in FIG. 6, and FIG. 7B is an enlarged view of a portion p in FIG. 7A. FIG. 7A is a front view of the converter transformer 11 for inspection, and 41 is a magnetic body of the converter transformer 11 for inspection. The magnetic sensor 39 is arranged close to the joining surface p of the magnetic body 41.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. 1, 6, and 7. FIG. As shown in FIG. 7A, in the converter transformer 11 to be inspected operated by the structure of FIG. Here, the magnetic material 4 in FIG.
When the gap r between the junction surfaces of the p-portion 1 increases, the leakage flux in the q-part increases, and when the converter transformer for inspection 11 is used in a mounting set, it becomes a noise source and poses a problem.
, The leakage flux detected by the sensor voltage detection circuit 40 and the leakage flux detected by the determination circuit 21 are determined by the determination circuit 21 to realize the leakage flux inspection of the converter transformer 11 to be inspected at the same time as the inspection of the first embodiment. be able to.

(Embodiment 6) Another embodiment of the present invention will be described below with reference to the drawings. FIG. 8 shows a configuration diagram from the output circuit to the determination circuit of the converter transformer inspection device according to the sixth embodiment of the present invention.
In FIG. 8, reference numeral 11 denotes another converter transformer to be inspected of the converter transformer inspection apparatus according to the first embodiment, 22 is a primary winding of the converter transformer 11, 23 is a control winding of the converter transformer 11, 42
Is the non-control winding of the converter transformer 11, and 19 is the first winding.
20 is a first load device, 43 is a second output circuit, 44 is a second load device, 21 is a judgment circuit, which connects the control winding 23 of the converter transformer 11 to be tested to the first output circuit. 19, the output of the first load device 20 is applied to the determination circuit 21, and the non-control winding 42 of the converter transformer 11 to be inspected is
Is connected to a second load device 44 via a second output circuit 43, and the output of the second load device 44 is applied to the determination circuit 21.

The operation of the converter transformer inspection apparatus configured as described above will be described with reference to FIGS. 8, the output voltage V _S2 of the control winding 23 of the converter transformer 11 to be inspected is detected by the first load device 20, and the output voltage V _S2 of the non-control winding 42 of the converter transformer 11 to be inspected is converted to the second voltage. And the determination circuit 21 determines V _S2 / V _S1 . Here, the converter transformer 11 to be inspected
The output voltage V _O1 of the control winding 23 when operating in the mounting set is controlled to a constant voltage.

The converter transformer 11 to be inspected
Is operated in the mounting set, the output voltage V _O2 of the non-control winding 42 is expressed by the following equation.

[0046]

(Equation 8)

Between the output voltage ratio obtained by V _S2 / V _S1 and (Equation 8)

[0048]

(Equation 9)

By multiplying the output voltage ratio obtained by V _S2 / V _S1 by the control voltage V _O1 in the mounting set, it is possible to obtain the non-control winding voltage V _O2 in the mounting set. By managing V _S2 / V _S1 , it is possible to realize the inspection of the voltage of the non-control winding 42 when the control winding 23 is controlled to a constant voltage in the mounting set.

[0050]

As described above, the present invention connects a primary winding of a converter transformer to be inspected to a DC power supply via a switching element, and provides a switching element applied voltage detection circuit in parallel with the switching element. A primary winding current detection circuit is provided in series with the element, an overvoltage protection circuit is connected to the switching element applied voltage detection circuit, an overcurrent protection circuit is connected to the primary winding current detection circuit, and a converter transformer for inspection is provided. A load device is connected to the secondary winding via an output circuit, an output of the load device is applied to a determination circuit, and outputs of the overvoltage protection circuit and the overcurrent protection circuit are applied to a pulse generation circuit. To apply a high-voltage pulse waveform to the primary winding of the converter transformer and consume the load from the secondary winding. An excellent converter transformer inspection that can be operated and inspected in a state close to the actual operation of the transformer, and protects the inspection equipment by the protective operation against abnormal converter transformers and can detect abnormal converter transformers. The device can be realized.

Further, a peak detection circuit is connected to the output of the primary winding current detection circuit, and a primary winding peak current detection block configured to apply the output of the peak detection circuit to the judgment circuit is added to the output. Inspection of the characteristics of the iron core used in the inspection converter transformer can be realized at the same time.

Further, a peak detection circuit is connected to the output of the switching element applied voltage detection circuit, and a switching element applied peak voltage detection block configured to apply the output of the peak detection circuit to the determination circuit is added, thereby simultaneously receiving the output. It is possible to realize the inspection whether the switching element may be damaged beyond the maximum rating of the switching element when used in the mounting set due to the increase of V _DSP2 due to the leakage inductance L _LEAK of the converter converter for inspection. it can.

A peak detection circuit is connected to the output of the switching element applied voltage detection circuit via a low-pass filter circuit having a cutoff frequency set at 300 kHz to 1 MHz, and the output of the peak detection circuit is applied to a judgment circuit. By adding a switching voltage detection block configured as described above, it is possible to guarantee the operation of the converter transformer inspection device itself, and to improve the inspection accuracy.

Further, the magnetic sensor is disposed close to the junction of the magnetic body of the converter transformer to be inspected, the magnetic sensor is connected to a sensor voltage detection circuit, and the output of the sensor voltage detection circuit is applied to a determination circuit. By adding the leakage flux detection block configured as described above, the inspection of the leakage flux of the converter transformer to be inspected can be realized simultaneously with the inspection.

In addition, the control winding of the converter transformer to be tested is connected to a first load device via a first output circuit, and the output of the first load device is applied to a determination circuit.
In addition, the non-control winding of the converter
The second load device is connected via the output circuit of
Is configured to apply the output of the load device to the determination circuit,
A voltage obtained from the first load device and a second
Inspection of non-control winding voltage when the control winding is controlled to a constant voltage in the mounting set by adding an output voltage ratio determination function configured to be able to determine based on the voltage ratio obtained from the load device of It can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a converter transformer inspection apparatus according to a first embodiment of the present invention.

2A is a characteristic diagram showing a voltage waveform diagram of a portion a in FIG. 1. FIG. 2B is a characteristic diagram showing a voltage waveform diagram of a c portion in FIG. 1. FIG. 2C is a voltage waveform diagram of a d portion in FIG. Characteristic diagram (d) Characteristic diagram showing a voltage waveform diagram of a portion e in FIG.

FIG. 3 is a configuration diagram of a primary winding peak current detection block of a converter transformer inspection device according to a second embodiment of the present invention;

FIG. 4 is a configuration diagram of a switching element applied peak voltage detection block of a converter transformer inspection apparatus according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a switching voltage detection block of a converter transformer inspection device according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a leakage flux detection block of a converter transformer inspection device according to a fifth embodiment of the present invention.

FIG. 7A is a layout view of a magnetic sensor of a leakage flux detection block of a converter transformer inspection device according to a fifth embodiment of the present invention. FIG.

FIG. 8 is a configuration diagram from an output circuit to a determination circuit of a converter transformer inspection device according to a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional converter transformer inspection device using a sine wave oscillator.

FIG. 10 is a configuration diagram of a converter transformer inspection apparatus according to a conventional mounting set.

[Explanation of symbols]

 Reference Signs List 11 Converter transformer for inspection 12 DC power supply 13 Switching element 14 Switching element applied voltage detection circuit 15 Primary winding current detection circuit 16 Overvoltage protection circuit 17 Overcurrent protection circuit 18 Pulse generation circuit 19 Output circuit 20 Load device 21 Judgment circuit 22 Primary Winding 23 Secondary winding 31 Switching element applied voltage waveform 32 Primary winding current waveform 33 Primary winding voltage waveform 34 Secondary winding voltage waveform 35 Peak detection circuit 36 Peak detection circuit 37 Low-pass filter 38 Peak detection circuit 39 Magnetic sensor Reference Signs List 40 sensor voltage detection circuit 41 magnetic material 42 non-control winding 43 output circuit 44 load device

Continued on the front page (72) Inventor Yu Yoshihara 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) H01F 41/00 G01R 31/00

Claims (6)

(57) [Claims] 1. A primary winding of a converter transformer to be tested is connected to a DC power supply via a switching element, a switching element applied voltage detection circuit is provided in parallel with the switching element, and a primary winding current is connected in series with the switching element. A detection circuit is provided, an overvoltage protection circuit is connected to an output of the switching element applied voltage detection circuit, an overcurrent protection circuit is connected to an output of the primary winding current detection circuit, and a secondary winding of the converter transformer to be inspected is provided. A load device is connected to the line via an output circuit, an output of the load device is applied to a determination circuit, and outputs of the overvoltage protection circuit and the overcurrent protection circuit are applied to a pulse generation circuit capable of setting a frequency and a duty ratio. Inspection equipment for converter transformers. 2. A primary winding peak current detecting block, wherein a peak detecting circuit is connected to an output of the primary winding current detecting circuit, and the output of the peak detecting circuit is applied to a determination circuit. Converter transformer inspection equipment. 3. A switching element applied peak voltage detection block, wherein a peak detection circuit is connected to an output of the switching element applied voltage detection circuit, and the output of the peak detection circuit is applied to a determination circuit. Converter transformer inspection equipment. 4. A peak detection circuit is connected to the output of the switching element applied voltage detection circuit via a low-pass filter circuit having a cutoff frequency set to 300 kHz to 1 MHz, and the output of the peak detection circuit is applied to a judgment circuit. 2. The converter transformer inspection device according to claim 1, further comprising a switching voltage detection block configured to perform the operation. 5. A magnetic sensor, wherein the magnetic sensor is disposed close to a junction of a magnetic body of a converter transformer to be inspected, the magnetic sensor is connected to a sensor voltage detection circuit, and an output of the sensor voltage detection circuit is applied to a determination circuit. The converter transformer inspection apparatus according to claim 1, further comprising a leakage flux detection block configured to perform the operation. 6. A control winding of a converter transformer to be inspected is connected to a first load device via a first output circuit, an output of said first load device is applied to a judgment circuit, A second load device is connected to a non-control winding of the converter transformer via a second output circuit, and the output of the second load device is applied to a determination circuit. The converter transformer inspection apparatus according to claim 1, further comprising an output voltage determination function configured to be able to determine based on a ratio between a voltage obtained from the first load device and a voltage obtained from the second load device.