JP6672420B2 - Test power supply generation method - Google Patents

Description

  The present invention relates to a method of generating a test power supply, and more particularly, to an improvement of a test power supply that supplies power to a device under test that is supplied with AC power of a fundamental frequency.

  Examples of power devices supplied with AC power of a fundamental frequency from a commercial power source include a PCS (Power Conditioning System) that converts the output of a solar cell or a fuel cell. This type of power device is required to be compatible with a tolerance test for voltage fluctuation of a commercial power supply. For example, EMC (Electro-Magnetic Compatibility) test standards require immunity (electromagnetic immunity) to a composite wave in which voltage waveforms of various frequencies are superimposed as interference waves on a voltage waveform of a fundamental frequency. . In the tolerance test, it is determined whether or not the power device operates normally even if the voltage waveform supplied from the power device is distorted.

  A test power supply for performing the above-described tolerance test is called an AC simulator, and a power supply of a linear amplifier type is known. A power supply device of the linear amplifier type is a device that adds a harmonic signal generated by a signal generator to a signal of a fundamental frequency and amplifies power using an amplifying action of an active element, and has a rated output of several kVA at most.程度 about several tens kVA. For this reason, there was a problem that it was not suitable for the resistance test of a large-capacity PCS.

  Therefore, it is conceivable to perform a tolerance test using an inverter type power supply device. An inverter type power supply device is a device that generates a synthetic wave by operating an inverter including a plurality of switching elements at a predetermined switching frequency, and can easily increase the capacity. For example, since the fundamental frequency is 50 Hz or 60 Hz, a switching frequency of about several kHz to about several tens kHz is used. However, in the EMC test standard described above, it is necessary to generate a higher-order harmonic such as 40 times the fundamental frequency. When high-order harmonics are generated at a switching frequency of about several kHz to several tens of kHz, there is a problem that a voltage waveform is distorted due to insufficient resolution.

  On the other hand, by increasing the switching frequency, it is possible to prevent distortion of the higher-order harmonic waveform. However, when the switching frequency is increased, there is a problem that power loss due to switching increases.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a test power supply device that can easily have a large capacity and can generate a higher-order harmonic waveform. In particular, it is an object of the present invention to provide a test power supply device capable of preventing an increase in power loss due to a switching operation and preventing a high-order harmonic waveform from being distorted.

  A test power supply according to a first aspect of the present invention is a test power supply for a fundamental frequency, comprising: a low-band inverter that generates a voltage waveform of the fundamental frequency as a fundamental wave; and a switching higher than the low-band inverter. A high-band inverter that operates at a frequency and generates a voltage waveform of a high-band test frequency equal to or higher than a first threshold frequency predetermined as a frequency higher than the fundamental frequency as an interference wave, the low-band inverter and the high-band inverter Are connected to the primary coil and the secondary coil, respectively, and include a transformer coupling circuit for superimposing the interfering wave on the fundamental wave, and test frequency designating means for designating the high band test frequency.

  According to such a configuration, power amplification is performed by the switching operation of the low-band inverter and the high-band inverter, so that it is easy to increase the capacity. Further, since the interference wave is generated by the high-band inverter operating at a higher switching frequency than the low-band inverter, it is possible to prevent the high-order harmonic waveform from being distorted. Further, since the transformer coupling circuit superimposes the interfering wave on the fundamental wave, an increase in power loss due to the switching operation can be suppressed as compared with the case where power amplification is performed by one inverter.

  In the test power supply device according to the second aspect of the present invention, in addition to the above-described configuration, the low-band inverter includes a low-band inverter having a low-band frequency lower than a second threshold frequency that is predetermined as a frequency equal to or higher than the first threshold frequency. A composite wave on which a voltage waveform of a test frequency is superimposed is generated, and the test frequency designating means is configured to designate the low band test frequency. According to such a configuration, it is possible to generate a composite wave in which the voltage waveform of the low band test frequency is superimposed on the fundamental wave as an interference wave.

  In the test power supply device according to the third aspect of the present invention, in addition to the above-described configuration, the low-band inverter includes a harmonic that is an integral multiple of the fundamental frequency or an inter-order harmonic that is a non-integer multiple of the fundamental frequency. The inter-order harmonic is configured to include a voltage waveform that is less than one time the fundamental frequency.

  According to such a configuration, not only a synthesized wave in which a harmonic of an integral multiple of the fundamental frequency is superimposed as an interference wave, but also a synthesized wave in which a non-integer harmonic of a non-integer multiple of the fundamental frequency is superimposed as an interference wave. Can be generated.

  In the test power supply device according to the fourth aspect of the present invention, in addition to the above configuration, the fundamental frequency is 50 Hz or 60 Hz, the low-band inverter operates at a switching frequency of 20 kHz or less, and the test frequency designation unit The low-band test frequency and the high-band test frequency are designated as the first threshold frequency and the second threshold frequency within a range of 12 times or less of the fundamental frequency.

  According to such a configuration, it is possible to suppress occurrence of distortion in the synthesized waveform generated by the low-band inverter and to suppress an increase in switching loss in the high-band inverter.

  According to a fifth aspect of the present invention, in addition to the above-described configuration, the test power supply device is configured such that the high-band inverter has a smaller output than the low-band inverter. According to such a configuration, an increase in power loss due to the switching operation can be suppressed.

  A test power supply device according to a sixth aspect of the present invention includes a capacitor connected in parallel to the primary coil of the transformer coupling circuit in addition to the above configuration, wherein a leakage inductance of the primary coil and the capacitor are different from each other. The high band inverter is configured to form a carrier removal filter.

  According to such a configuration, it is possible to remove the switching frequency component from the output of the high-band inverter while suppressing an increase in the number of parts, as compared with a case where the coil for the carrier removal filter is provided separately from the transformer coupling circuit. it can.

  A test power supply device according to a seventh aspect of the present invention further includes a converter that generates a DC voltage using a commercial power supply, in addition to the above configuration, wherein the low-band inverter and the high-band inverter share a common converter. It is configured to generate a voltage waveform using the supplied DC voltage. According to such a configuration, the size of the device can be reduced as compared with a case where a converter is provided for each inverter.

  The test power supply according to the eighth aspect of the present invention is configured such that, in addition to the above-described configuration, the high-bandwidth inverter includes a field-effect transistor using silicon carbide. According to such a configuration, power loss in the high-bandwidth inverter can be reduced as compared with the case where the high-bandwidth inverter is formed of an insulated gate bipolar transistor using silicon.

  According to the present invention, it is possible to provide a test power supply device that can easily increase the capacity and can prevent distortion of a higher-order harmonic waveform. In particular, it is possible to prevent an increase in power loss due to the switching operation and to prevent distortion in a higher-order harmonic waveform.

FIG. 1 is a system diagram showing one configuration example of a test power supply device 1 according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of a power generation unit 12 in FIG. 1. FIG. 3 is a diagram illustrating details of a high-bandwidth inverter 123 and a transformer coupling circuit 124 in FIG. 2. FIG. 3 is a block diagram illustrating a configuration example of an inverter control circuit 129 of FIG. 2. FIG. 3 is a diagram illustrating an operation example of a power generation unit 12 in FIG. 2.

<Test power supply 1>
FIG. 1 is a system diagram showing one configuration example of a test power supply device 1 according to an embodiment of the present invention. FIG. 1 shows a test power supply 1 connected to a PCS (Power Conditioning System) 2 to be inspected. The PCS 2 is a power converter that converts DC power generated by a solar cell or a fuel cell into AC power, and outputs the AC power to a power system at a stable voltage and frequency.

  The test power supply device 1 is an AC simulator that supplies power to a device under test that is supplied with AC power having a fundamental frequency f0. Voltage waveforms of various frequencies are superimposed on the voltage waveform of the fundamental frequency f0 as interference waves. Various resistance tests are performed by generating the synthesized waves. The test power supply device 1 generates a composite wave based on a test frequency instruction from the information processing terminal 11 that specifies a fundamental frequency f0 and a test frequency for an endurance test, and supplies power to the PCS 2. And a power supply generation unit 12 for applying the voltage as a power supply.

  The information processing terminal 11 is, for example, a personal computer that operates based on an application program for a resistance test. The information processing terminal 11 specifies a low-band test frequency f1 lower than the threshold frequency fts1 or generates a test frequency instruction for specifying a high-band test frequency f2 equal to or higher than the threshold frequency fts2. Output.

  Each of the threshold frequencies fts1 and fts2 is a fixed value of a frequency higher than the fundamental frequency f0, and is predetermined. The threshold frequency fts1 is equal to or higher than the threshold frequency fts2. The low-band test frequency f1 and the high-band test frequency f2 are specified based on a user operation, or are automatically specified according to a predetermined test schedule.

  The basic frequency f0 corresponds to the frequency of the commercial power supply 3, for example, f0 = 50 Hz. The information processing terminal 11 designates the low-band test frequency f1 and the high-band test frequency f2 as threshold frequencies fts1 and fts2 within a range of 12 times or less the fundamental frequency f0. The threshold frequencies fts1 and fts2 are, for example, fts1 = fts2, and nine times the fundamental frequency f0, that is, fts1, fts2 = 450 Hz is used.

  The low band test frequency f1 is specified within a range of 0.33 times or more and less than 9 times the fundamental frequency f0. On the other hand, the high band test frequency f2 is specified within a range from 9 times to 40 times the basic frequency f0. By employing such a configuration, it is possible to perform various resistance tests defined by the EMC test standards.

  For example, an individual harmonic test, an interharmonic test, and a frequency sweep test can be performed. The individual harmonic test is a tolerance test in which harmonics from the second to the 40th are sequentially superimposed. The inter-harmonic test is a tolerance test in which a voltage waveform that is a non-integer multiple of the fundamental frequency f0 is called an inter-harmonic, and the inter-harmonic is superimposed. The frequency sweep test is a tolerance test in which harmonics from the 0.33 order to the 40th order are superimposed stepwise or continuously. If the fundamental frequency f0 is f0 = 60 Hz, fts = 540 Hz is used as the threshold frequency fts.

  The power generation unit 12 is an inverter unit that generates a desired AC voltage as a power supply by using power supplied from the commercial power supply 3. The commercial power supply 3 supplies AC power having a frequency of 50 Hz and an effective value of voltage of 420 V to the power generation unit 12, for example, in a three-phase three-wire system.

<Power generation unit 12>
FIG. 2 is a diagram showing a configuration example of the power generation unit 12 of FIG. The power generation unit 12 includes a converter 121, a low-band inverter 122, a high-band inverter 123, a transformer coupling circuit 124, a switch 125, an output terminal 126, a converter control circuit 127, inverter control circuits 128 and 129.

  The converter 121 is a converter that generates a DC voltage using a commercial power supply, and includes a plurality of switching elements, for example, an IGBT (Insulated Gate Bipolar Transistor). The converter 121 converts an AC voltage input from a commercial power supply into a DC voltage, and outputs the DC voltage to the low-band inverter 122 and the high-band inverter 123. Each switching element of converter 121 switches according to gate drive signal GS. The DC voltage output from converter 121 is, for example, 650V.

  The low-band inverter 122 is a switching converter that converts a DC voltage input from the converter 121 into a low-band AC voltage and outputs the DC voltage from an output terminal 126 via a transformer coupling circuit 124 or a switch 125. , For example, an IGBT. Each switching element of the low-band inverter 122 switches according to the gate drive signal GS1.

  The low-band inverter 122 operates at a predetermined switching frequency fs1, for example, fs1 = 7 kHz, generates a voltage waveform of the fundamental frequency f0 as a fundamental wave, or generates a voltage waveform of the low-band test frequency f1 in the fundamental wave. A superimposed composite wave is generated as an interference wave. The voltage level of the interfering wave superimposed on the fundamental wave by the low-band inverter 122 is about 0 to about 10% of the voltage level of the fundamental wave. The switching frequency fs1 may be a frequency higher than several kHz, for example, tens of kHz, specifically, 16 kHz to 18 kHz.

  In addition, the low-band inverter 122 generates a composite wave in which a harmonic that is an integral multiple of the fundamental frequency f0 is superimposed as an interference wave, or an interharmonic that is a non-integer multiple of the fundamental frequency f0 is superimposed as an interference wave. . The inter-order harmonic includes a voltage waveform that is less than one time the fundamental frequency f0.

  The high-band inverter 123 is a switching converter that converts a DC voltage input from the converter 121 to a high-band AC voltage and outputs the converted AC voltage to the transformer coupling circuit 124, and includes a plurality of switching elements. Each switching element of the high-bandwidth inverter 123 switches according to the gate drive signal GS2.

  The high-band inverter 123 operates at a switching frequency fs2 higher than that of the low-band inverter 122, for example, fs2 = 42 kHz, and generates a voltage waveform of the high-band test frequency f2 as an interference wave. Further, the output of the high-band inverter 123 is smaller than that of the low-band inverter 122. For example, while the output of the low-band inverter 122 is about 800 kVA, the output of the high-band inverter 123 is about 150 kVA, which is １ ／ or less of that of the low-band inverter 122.

  The transformer coupling circuit 124 is a transformer circuit for superimposing the interference wave generated by the high-band inverter 123 on the fundamental wave generated by the low-band inverter 122. The low-band inverter 122 and the high-band inverter 123 Connected to the primary coil and the secondary coil, respectively. The voltage level of the interfering wave superimposed on the fundamental wave by the transformer coupling circuit 124 is about 0 to several tens% of the voltage level of the fundamental wave.

  The switch 125 is an electromagnetic switching type switch that conducts when outputting a power supply of the low band test frequency f1 and shuts off when outputting a power supply of the high band test frequency f2, and is connected in parallel to the transformer coupling circuit 124. Is done.

  The ammeter 131 is a current detector for detecting the output current Iout of the low-band inverter 122, and is arranged between the low-band inverter 122 and the transformer coupling circuit 124. The output current Iout is a load current flowing through a load connected to the output terminal 126. The ammeter 132 is a current detector for detecting the output current Iinv of the high-band inverter 123, and is arranged between the high-band inverter 123 and the transformer coupling circuit 124.

  The voltmeter 133 is arranged between the ammeter 131 and the transformer coupling circuit 124, and detects the output voltage Vout of the low-band inverter 122. In the voltmeter 133, the primary coil and the secondary coil are each delta-connected to each phase of AC. The voltmeter 134 is arranged in parallel with the primary coil of the transformer coupling circuit 124, and detects the output voltage Vinv of the high-bandwidth inverter 123. In the voltmeter 134, the primary coil is star-connected to each phase of AC, and the secondary coil is delta-connected to each phase of AC.

  Converter control circuit 127 is a control circuit for controlling converter 121, generates gate drive signal GS, and outputs it to converter 121. The inverter control circuit 128 is a control circuit that controls the low-bandwidth inverter 122 based on a test frequency instruction from the information processing terminal 11, generates the gate drive signal GS1 with reference to the output current Iout and the output voltage Vout, Output to low-band inverter 122.

  The inverter control circuit 129 is a control circuit that controls the high-bandwidth inverter 123 based on a test frequency instruction from the information processing terminal 11, and refers to the output current Iout, the output current Iinv, and the output voltage Vinv to control the gate drive signal GS2. Is generated and output to the high-bandwidth inverter 123.

  In addition, when outputting the power of the low-band test frequency f1, the inverter control circuit 129 switches the switch 125 to the closed state (on state), thereby turning on the bypass path to the transformer coupling circuit 124, The band inverter 123 is stopped. On the other hand, when outputting the power of the high-band test frequency f2, the inverter control circuit 129 operates the high-band inverter 123 and then switches the switch 125 to the open state (off state), thereby forming the transformer coupling circuit 124. , And instructs the inverter control circuit 128 to select a fundamental wave.

  FIG. 3 is a diagram illustrating details of the high-bandwidth inverter 123 and the transformer coupling circuit 124 of FIG. The high-band inverter 123 includes six switching elements 4 and six freewheel diodes 5, and converts a DC input from the converter 121 into a three-phase three-wire AC voltage. The effective value of the voltage is, for example, 360V.

  As the switching element 4, a transistor with small power loss due to the switching operation, for example, an FET (Field Effect Transistor) using silicon carbide or the like is used.

  The freewheel diode 5 is a semiconductor element for protecting the switching element 4 and is connected in parallel between the source terminal and the drain terminal of the switching element 4. The gate drive signal GS2 from the inverter control circuit 129 is input to the gate terminal of the switching element 4.

  The transformer coupling circuit 124 includes three transformers 6, an open-star connection for connecting the primary coil of the transformer 6, the AC input from the low-band inverter 122, and the output terminal 126 to each other, and the secondary coil of the transformer 6 And a delta connection unit that connects the band inverter 123 to each other. The AC input from the low-band inverter 122 is a three-phase three-wire AC voltage, and the effective value is, for example, 420V.

  The configurations of the open star connection and the delta connection are as follows. One end of the primary coil is connected to the first phase of the AC input, and the other end of the secondary coil of the transformer 6 is connected to the output terminal 126 of the first phase. And the other end is connected to the second phase. One end of the primary coil is connected to the second phase of the AC input, and the other end is connected to the output terminal 126 of the second phase. And the other end is connected to the third phase. The secondary coil of the transformer 6 having one end connected to the third phase of the AC input and the other end connected to the third-phase output terminal 126 has one end connected to the third phase of the high-bandwidth inverter 123. And the other end is connected to the first phase.

  A capacitor 130 is connected to the transformer coupling circuit 124 in parallel with the primary coil. The capacitor 130 is a capacitive element for forming a carrier removal filter of the high-band inverter 123 by using the capacitor 130 and the leakage inductance of the primary coil. This capacitor 130 is provided for each transformer 6 and is connected in parallel to the primary coil of the transformer 6.

  The switch 125 is connected in parallel to the primary coil of the transformer coupling circuit 124, and forms a bypass path to the transformer coupling circuit 124 in the closed state. This switch 125 is provided for each transformer 6 and is connected in parallel to the primary coil of the transformer 6.

<Inverter control circuit 129>
FIG. 4 is a block diagram showing a configuration example of the inverter control circuit 129 of FIG. The inverter control circuit 129 includes an effective value command generation unit 21, an effective value calculation unit 22, an effective value voltage control unit 23, an instantaneous voltage waveform control unit 24, a phase matching unit 25, an adder 26, a peak cut limiter 27, an instantaneous current It comprises a waveform control unit 28 and a gate drive signal generation unit 29.

  The effective value command generator 21 generates an effective value command for determining the effective value of the output voltage Vinv. The effective value calculation unit 22 calculates an effective value from the output voltage Vinv detected by the voltmeter 134. The effective value voltage control unit 23 is a control unit that performs feedback control so that the effective value of the output voltage Vinv is constant, and includes a subtractor 231 and a waveform command generation unit 232.

  The subtractor 231 subtracts the effective value obtained by the effective value calculation unit 22 from the effective value command generated by the effective value command generation unit 21 to generate an error of the effective value command, and generates a waveform command generation unit 232. Output to The waveform command generation unit 232 generates a waveform command for determining the voltage waveform of the output voltage Vinv based on the test frequency command from the information processing terminal 11 and the error of the effective value command from the subtractor 231. The waveform command generator 232 includes, for example, an error amplifier and a sine wave generator, and creates a waveform command from the amplified error and the sine wave.

  The instantaneous voltage waveform control unit 24 is a control unit that performs feedback control of the instantaneous value of the output voltage Vinv, and includes an adder 241 and an inverter voltage PI control unit 242. The adder 241 adds the output voltage Vinv detected by the voltmeter 134 in reverse phase to the waveform command generated by the waveform command generator 232 to generate an error in the waveform command, and the inverter voltage PI controller 242 Output to Inverter voltage PI control unit 242 generates a waveform command for determining the current waveform of output current Iinv based on the error of the waveform command from adder 241. The PI control of the inverter voltage is feedback control that controls the output as a linear function of the error between the waveform command and the detected value of the output voltage Vinv, and changes the output according to the integration of the error.

  The phase matching unit 25 matches the waveform command of the inverter voltage PI control unit 242 by shifting the phase of the output current Iout detected by the ammeter 131 by a certain amount. The phase matching unit 25 is a phase shifter that matches the detected value of the output current Iout with the phase on the secondary coil side of the transformer coupling circuit 124, and delays the phase of the detected value by 30 °. The phase shift of 30 ° corresponds to the phase difference between the star connection on the primary coil side and the delta connection on the secondary coil side.

  The adder 26 adds the detected value of the output current Iout from the phase matching unit 25 to the waveform command generated by the inverter voltage PI control unit 242 in the same phase as the current command, and outputs the current command to the peak cut limiter 27. The peak cut limiter 27 is a circuit for preventing an overcurrent when a load is short-circuited. The instantaneous current waveform control unit 28 is a control unit that performs feedback control of the instantaneous value of the output current Iinv, and includes the adders 281 and 283 and the inverter current PI control unit 282.

  Since the output current Iout is a load current actually flowing through the load connected to the output terminal 126, the instantaneous current waveform command is obtained by adding the detected value of the output current Iout in the same phase as the waveform command of the output current Iinv. By setting the value, feedforward control for operating the high-bandwidth inverter 123 in the constant current operation state is performed.

  When switching from the power supply of the low band test frequency f1 to the power supply of the high band test frequency f2, the switch 125 is switched to the open state, whereby the bypass path of the transformer coupling circuit 124 is cut off. At this time, a voltage is applied to both ends of the primary coil of the transformer coupling circuit 124 by the feedforward control of the high-band inverter 123 so that the load current before the interruption is maintained. The power supply can be continuously switched to the test frequency f2.

  The adder 281 adds the output current Iinv detected by the ammeter 132 in reverse phase to the waveform command from the peak cut limiter 27 to generate a waveform command error, and outputs the error to the inverter current PI control unit 282. . Inverter current PI control unit 282 generates a waveform command value of output voltage Vinv based on the error of the waveform command from adder 281. Adder 283 adds the waveform command generated by waveform command generator 232 to the waveform command value generated by inverter current PI controller 282 in the same phase, and outputs the result to gate drive signal generator 29.

  Gate drive signal generation section 29 generates a gate drive signal GS2 based on the waveform command value from adder 283, and outputs it to high-band inverter 123. The gate drive signal generation unit 29 is composed of a PWM (pulse width modulation) drive circuit, and generates a pulse-shaped gate drive signal GS2. The gate drive signal generation unit 29 includes, for example, a signal oscillator that generates a triangular wave signal, and a comparator that compares a waveform command value with the triangular wave signal. The frequency of the triangular wave signal, that is, the carrier frequency is fs2 = 42 kHz.

  Similarly to inverter control circuit 129, inverter control circuit 128 also generates gate drive signal GS1 based on output current Iout detected by ammeter 131 and output voltage Vout detected by voltmeter 133.

  FIG. 5 is a diagram illustrating an operation example of the power generation unit 12 in FIG. 2, and illustrates a state in which the gate drive signal GS <b> 2 is generated from the waveform command value 7 and the triangular wave signal 8. The waveform command value 7 is a command value when f2 = 2.4 kHz is designated as the highest-order (40th-order) high-band test frequency f2 when the basic frequency f0 is 60 Hz. The carrier frequency of the triangular wave signal 8 is 42 kHz.

  The gate drive signal GS2 is a rectangular wave whose voltage level is switched between high and low at the intersection of the sinusoidal waveform command value 7 and the triangular wave signal 8. Even with such a high-order high-band test frequency f2, since the carrier frequency is high, sufficient resolution can be obtained, and distortion of a harmonic waveform can be prevented.

  According to the present embodiment, since power amplification is performed by the switching operation of low-band inverter 122 and high-band inverter 123, it is easy to increase the capacity. In addition, since a high-order interference wave is generated by the high-band inverter 123 operating at the switching frequency fs2 higher than that of the low-band inverter 122, it is possible to prevent the high-order harmonic waveform from being distorted. Further, since the transformer coupling circuit 124 superimposes a higher-order interfering wave on the fundamental wave, an increase in power loss due to the switching operation can be suppressed as compared with the case where power amplification is performed by one inverter.

  In addition, since the leakage inductance of the transformer coupling circuit 124 and the capacitor 130 form a carrier removal filter of the high-band inverter 123, the number of components is smaller than when a coil for the carrier removal filter is provided separately from the transformer coupling circuit 124. The switching frequency component can be removed from the output of the high-bandwidth inverter 123 while suppressing the increase.

  Further, since the low-band inverter 122 and the high-band inverter 123 generate a voltage waveform using the DC voltage supplied from the common converter 121, the size of the device can be reduced as compared with a case where a converter is provided for each inverter. Can be. Further, since high-band inverter 123 is formed of an FET using silicon carbide, power loss of high-band inverter 123 can be reduced as compared with a case where high-band inverter 123 is formed of an IGBT using silicon.

  Note that, in the present embodiment, an example has been described in which high-band inverter 123 is formed of an FET using silicon carbide, but the present invention does not limit the configuration of high-band inverter 123 to this. For example, the high-bandwidth inverter 123 may be constituted by an FET or an IGBT.

  Further, in the present embodiment, an example in which the power generation unit 12 of the test power supply device 1 is configured by two inverter circuits has been described. However, in the present invention, the power generation unit 12 is configured by three or more inverter circuits. The present invention is also applicable to components. For example, the output may be increased by connecting two low-band inverters 122 in parallel.

  Further, in the present embodiment, an example has been described in which the threshold frequency fts1 and the threshold frequency fts2 are made to coincide with each other so that the low band test frequency f1 and the high band test frequency f2 do not overlap. However, the present invention may be configured such that the adjustment range of the low-band test frequency f1 and the adjustment range of the high-band test frequency f2 overlap by setting the frequency exceeding the threshold frequency fts2 as the threshold frequency fts1.

DESCRIPTION OF SYMBOLS 1 Test power supply device 11 Information processing terminal 12 Power generation unit 121 Converter 122 Low band inverter 123 High band inverter 124 Transformer coupling circuit 125 Switch 126 Output terminal 127 Converter control circuit 128, 129 Inverter control circuit 130 Capacitor 131, 132 Ammeter 133,134 Voltmeter 2 PCS
3 Commercial power supply 4 Switching element 5 Reflux diode 6 Transformer 7 Waveform command value 8 Triangular wave signal

Claims (5)

A method of generating a test power supply for performing a voltage waveform distortion tolerance test on an inspection target device to which an AC power supply of a fundamental frequency is supplied ,
Using a low-band inverter, selectively generating a fundamental wave composed of a voltage waveform of the fundamental frequency or a synthesized wave in which a low-band interfering wave is superimposed on the fundamental wave,
Generating a high-band interference using a high-band inverter operating at a higher switching frequency than the low-band inverter;
Superimposing the high-band interference wave on the fundamental wave or the synthesized wave using a transformer coupling circuit,
A method for generating a test power supply, wherein a waveform in which the low-band interference wave or the high-band interference wave is superimposed on the fundamental wave is generated as the test power supply. Specifying a test frequency,
If the test frequency is less than a first threshold frequency, the low-band inverter generates the composite wave;
The method according to claim 1, wherein the low-band inverter generates the fundamental wave when the test frequency is equal to or higher than the first threshold frequency.   When the test frequency is equal to or higher than a second threshold frequency which is predetermined as a frequency equal to or lower than the first threshold frequency, the high-band inverter generates a high-band interference wave corresponding to the test frequency. A method for generating a test power supply according to claim 2. As the test frequency, a frequency that sequentially changes over the first threshold frequency is designated,
The method for generating a test power supply according to claim 3, wherein the test power supply for a frequency sweep test is generated.   The method according to claim 3, wherein the first threshold frequency and the second threshold frequency are the same.

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