A test device for high voltage DC power panels

Abstract

The utility model relates to a kind of testing device suitable for high-voltage direct-current power panel, belong to high-voltage direct-current power panel test technical field.This scheme according to the direct current voltage required by the measured high-voltage direct-current power panel test, control switch on the parallel branch of corresponding secondary winding is in the on state, the control switch on the parallel branch of the rest secondary winding is all disconnected, to convert the voltage of the ac power supply that the transformer primary side is externally connected by the secondary winding of parallel branch in the on state, and then convert the ac power output by the transformer into dc power by rectifier, finally obtain the direct current voltage required by the measured high-voltage direct-current power panel test.This scheme outputs at least two ac by transformer, and then outputs at least two different voltage levels of direct current voltage required by the measured high-voltage direct-current power panel test after rectification, meets direct current power supply test, saves output voltage adjustment time, effectively improves the test efficiency of high-voltage direct-current power panel.

Description

Technical Field

[0001] This utility model relates to a testing device suitable for high-voltage DC power supply boards, belonging to the field of high-voltage DC power supply board testing technology. Background Technology

[0002] Existing as Figure 1 The diagram shows an improved online testing device for a converter based on PWM control. The specific details of this device are as follows:

[0003] (1) Key parameter description:

[0004] ① The capacity of transformer TR1 is 4kVA, the turns ratio is 380:2000, and the maximum system current is 18A;

[0005] ② Load resistance: Three-phase load (3*2Ω), i.e., R1=R2=R3=2Ω;

[0006] ③ The voltage regulator TS1 has a capacity of 9kVA, AC 0-430V, and a maximum system current of 18A;

[0007] ④QS1: Voltage regulator switch, QS2: Transformer switch, QS3: Rectifier bridge switch, QS4: Resistor load switch;

[0008] ⑤DB1 and DB2 form a rectifier bridge connected to DC output 1, and DB3 is a rectifier bridge connected to DC output 2;

[0009] ⑥LD1: Power indicator light; When the AC input is 380V, the power indicator light LD1 will light up.

[0010] (2) How to use the online testing device for converters:

[0011] ① DC overvoltage test: Select the DC 0-2500V output terminals, that is, select DC1+ and DC1- of DC output 1, and close the voltage regulator switch QS1 and the transformer switch QS2 in sequence;

[0012] ② Open-loop test: Select the DC 0-600V output terminals, that is, select DC2+ and DC2- of DC output 2, and close the voltage regulator switch QS1 and the rectifier bridge switch QS3 in sequence;

[0013] ③ Single closed-loop test: Select the DC 0-600V output terminals, that is, select DC2+ and DC2- of DC output 2, and close the voltage regulator switch QS1, rectifier bridge switch QS3, and resistive load switch QS4 in sequence;

[0014] ④ AC overvoltage test: Select the two-phase power output terminals of AC 0-2000V, that is, select the two-phase AC output U1 and V1, and close the voltage regulator switch QS1 and the transformer switch QS2 in sequence.

[0015] (3) Precautions for using the online converter testing device:

[0016] ① The voltage regulator should be reset to zero in a timely manner. This must be checked and confirmed before each power-on and reset to zero promptly after the test.

[0017] ②Before adjusting the terminals, be sure to disconnect the power (AC input 380V line);

[0018] ③ Before adjusting the terminals, check if there is power in the DC connection.

[0019] (4) Existing technical problems:

[0020] ① The DC voltage output voltage response is slow, and the efficiency of the high-voltage DC power supply board is low.

[0021] When testing the high-voltage DC power supply board, the voltage regulator needs to be manually adjusted slowly to meet the DC 300V and DC 900V DC voltage power supply requirements for the test, which takes a long time.

[0022] ②The DC output circuit of the voltage regulator has no bleeder resistor, and manual bleedering poses a safety hazard;

[0023] After a single test piece is completed, there is no discharge circuit, so an external discharge resistor is required at the output end, which poses a risk of electric shock during disassembly.

[0024] ③ The voltage regulator is large and heavy, making it inconvenient to carry. It also requires an external AC 400V power supply and is only suitable for specific locations. Utility Model Content

[0025] The purpose of this invention is to provide a testing device suitable for high-voltage DC power supply boards, in order to solve the problem of low testing efficiency of existing high-voltage DC power supply boards.

[0026] To achieve the above objectives, the solution of this utility model includes:

[0027] This invention discloses a testing device for high-voltage DC power supply boards. The device includes a transformer, the primary side of which is used to connect to an external AC power source. The secondary side of the transformer includes at least two different secondary windings connected in parallel. Each parallel branch containing a secondary winding is connected in series with a control switch to control the conduction of its parallel branch and enable the transformer to perform voltage conversion for any parallel branch. The output terminals of the transformer are also connected to a rectifier for converting AC power to DC power to output the DC voltage required for testing the high-voltage DC power supply board under test.

[0028] The number of turns in the secondary winding is determined based on the voltage required for testing the high-voltage DC power supply board and the voltage conversion ratio determined by the AC power supply.

[0029] Furthermore, the control switch adopts the normally open contact of the winding relay. The normally open contact of the switching control relay is connected in series in the circuit where the winding coil of the winding relay is located. The switching control coil of the switching control relay is connected in series in the circuit where the switching regulation switch is located. When the switching regulation switch is closed, the switching control coil connected in series with the switching regulation switch is energized, and the corresponding normally open contact of the switching control is closed. In turn, the winding coil connected in series with the normally open contact of the switching control is energized, and the corresponding normally open contact of the winding is closed. The parallel branch where the normally open contact of the winding is located is connected, so that the transformer can perform voltage conversion of the parallel branch.

[0030] Furthermore, a soft start module is connected in series between the output terminal of the transformer and the rectifier. The soft start module includes a soft start switch connected in parallel and a soft start resistor for limiting the starting current.

[0031] Furthermore, the soft start switch adopts the soft start normally open contact of the soft start relay. The soft start coil of the soft start relay is connected in series with the soft start control normally open contact of the soft start control relay. The soft start control coil of the soft start control relay is connected in series with the soft start regulating switch. The soft start control relay adopts a time-delay type relay. When the soft start regulating switch is closed, the soft start control coil is energized, the soft start control normally open contact closes after a delay, and the soft start normally open contact closes. The branch where the soft start normally open contact is located bypasses the branch where the soft start resistor is located.

[0032] Furthermore, a capacitor is connected to the output of the rectifier, which is used to power the high-voltage DC power supply board under test.

[0033] Furthermore, the output terminal of the capacitor used to power the high-voltage DC power supply board under test is also connected in series with a bleed branch. The bleed branch is used to connect in parallel with the high-voltage DC power supply board under test so that the bleed branch can be activated after the high-voltage DC power supply board under test is tested. The bleed branch includes a bleed resistor connected in series and a bleed switch used to control the activation of the bleed branch.

[0034] Furthermore, the control switch uses the normally open contact of the winding relay, the normally closed contact of the winding relay is connected in series in the discharge branch, and the discharge switch uses the normally open contact of the discharge relay.

[0035] Furthermore, a voltmeter is connected in parallel to the output terminal of the capacitor to measure the voltage across the capacitor.

[0036] Furthermore, the primary side of the transformer is also connected in parallel with a heat dissipation branch for cooling the devices in the test apparatus. This heat dissipation branch includes a cooling fan connected in series and a heat dissipation switch for controlling the power supply to and from the cooling fan.

[0037] Furthermore, a power indicator light is connected in parallel on the primary side of the transformer to determine the AC power supply status by the on / off state of the power indicator light.

[0038] Furthermore, the rectifier employs a rectifier bridge.

[0039] Furthermore, the device also includes a digital voltmeter, which is connected in parallel to the output terminal of the high-voltage DC power supply board under test to measure its output voltage.

[0040] The beneficial effects of this utility model are:

[0041] This invention provides a testing device suitable for high-voltage DC power supply boards. The device uses a transformer whose secondary side includes at least two different secondary windings connected in parallel. The number of turns of the secondary windings is determined according to the voltage conversion ratio between the voltage required for testing the high-voltage DC power supply board and the AC power supply. The output terminals of the transformer are also connected to a rectifier for converting AC power to DC power to output the DC voltage required for testing the high-voltage DC power supply board. A control switch is connected in series on the parallel branch where each secondary winding is located to control the conduction of the parallel branch and realize the voltage conversion of any parallel branch by the transformer.

[0042] This scheme, based on the DC voltage required for testing the high-voltage DC power supply board, controls the closing of the control switch connected in series on the parallel branch containing the corresponding secondary winding, and the opening of the control switches on the parallel branches containing the remaining secondary windings. This allows the voltage of the AC power supply connected to the primary side of the transformer to be converted through the conducting secondary windings of the parallel branches. The AC power output from the transformer is then converted to DC power by a rectifier, ultimately obtaining the DC voltage required for testing the high-voltage DC power supply board. Unlike existing manual voltage regulators, this scheme outputs at least two AC circuits from the transformer, which, after rectification, output at least two different voltage levels of the DC voltage required for testing the high-voltage DC power supply board. This eliminates the need for voltage regulator operation, thus meeting the DC power supply testing requirements, saving output voltage adjustment time, and effectively improving the testing efficiency of the high-voltage DC power supply board. Attached Figure Description

[0043] Figure 1 This is the circuit schematic diagram of an existing online converter testing device;

[0044] Figure 2 This is the circuit diagram of the test device for the high-voltage DC power supply board. Detailed Implementation

[0045] In existing high-voltage DC power supply board testing, the power supply requirements need to be manually adjusted, which is inefficient and results in low testing efficiency. To solve this problem, this utility model provides a testing device that can meet the power supply requirements of high-voltage DC power supply board testing. It outputs at least two AC circuits through a transformer, and after rectification and filtering, outputs at least two DC voltages of different voltage levels to power the input terminal of the high-voltage DC power supply board. This eliminates the need to operate a voltage regulator to adjust the voltage, thus realizing DC power supply testing and saving the time required for output voltage adjustment.

[0046] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] An embodiment of a testing device suitable for high-voltage DC power supply boards:

[0048] A testing device for high-voltage DC power supply boards includes a transformer. The primary side of the transformer is used to connect to an external AC power supply. The secondary side of the transformer includes at least two different secondary windings connected in parallel. Each parallel branch containing a secondary winding is connected in series with a control switch to control the conduction of its parallel branch and enable the transformer to perform voltage conversion for any parallel branch. The output terminals of the transformer are also connected to a rectifier to convert AC power to DC power, so as to output the DC voltage required for testing the high-voltage DC power supply board under test. The number of turns of the secondary winding is determined according to the voltage conversion ratio between the voltage required for testing the high-voltage DC power supply board under test and the AC power supply.

[0049] This scheme, based on the DC voltage required for testing the high-voltage DC power supply board, controls the closing of the control switch connected in series on the parallel branch containing the corresponding secondary winding, and the opening of the control switches on the parallel branches containing the remaining secondary windings. This allows the voltage of the AC power supply connected to the primary side of the transformer to be converted through the conducting secondary windings of the parallel branches. The AC power output from the transformer is then converted to DC power by a rectifier, ultimately obtaining the DC voltage required for testing the high-voltage DC power supply board. Unlike existing manual voltage regulators, this scheme outputs at least two AC circuits from the transformer, which, after rectification, output at least two different voltage levels of the DC voltage required for testing the high-voltage DC power supply board. This eliminates the need for voltage regulator operation, thus meeting the DC power supply testing requirements, saving output voltage adjustment time, and effectively improving the testing efficiency of the high-voltage DC power supply board.

[0050] Specifically, the control switch uses the normally open contact of the winding relay. The normally open contact of the switching control relay is connected in series in the circuit where the winding coil of the winding relay is located. The switching control coil of the switching control relay is connected in series in the circuit where the switching regulation switch is located. When the switching regulation switch is closed, the switching control coil connected in series with the switching regulation switch is energized, and the corresponding normally open contact of the switching control is closed. In turn, the winding coil connected in series with the normally open contact of the switching control is energized, and the corresponding normally open contact of the winding is closed. The parallel branch where the normally open contact of the winding is located is connected, so that the transformer can perform voltage conversion of the parallel branch.

[0051] More specifically, considering the convenience and safety of control, the switching adjustment switch corresponding to the normally open contact control switch of the winding on each parallel branch of the secondary winding adopts any position of the rotary switch.

[0052] In another embodiment, the control switch uses the normally open contact of the winding relay. The normally open contact of the switching control relay is connected in series in the circuit where the winding coil of the winding relay is located. The normally open contact of the winding relay on each parallel branch where the secondary winding is located is connected in series in the circuit where the switching control coil of the corresponding switching control relay of the control switch is located. Any voltage switching position of the regulating switch is connected in parallel. When the regulating switch is in any voltage switching position, the switching control coil connected in series with that position is energized and the corresponding normally open contact of the switching control is closed. Then, the winding coil connected in series with the normally open contact of the switching control is energized and the corresponding normally open contact of the winding is closed. The parallel branch where the normally open contact of the winding is located is connected, so that the transformer can perform voltage switching at that position.

[0053] Specifically, a soft start module is connected in series between the output terminal of the transformer and the rectifier. The soft start module includes a soft start switch connected in parallel and a soft start resistor for limiting the starting current.

[0054] Specifically, the soft start switch uses the soft start normally open contact of the soft start relay. The soft start coil of the soft start relay is connected in series with the soft start control normally open contact of the soft start control relay. The soft start control coil of the soft start control relay is connected in series with the soft start regulating switch. The soft start control relay is a time-delay type relay. When the soft start regulating switch is closed, the soft start control coil is energized, the soft start control normally open contact closes after a delay, and the soft start normally open contact closes. The branch where the soft start normally open contact is located bypasses the branch where the soft start resistor is located.

[0055] More specifically, considering the convenience and safety of control, the soft start adjustment switch adopts any of the remaining positions of the rotary switch except for the one occupied by the changeover adjustment switch.

[0056] In another embodiment, the soft start switch uses the soft start normally open contact of the soft start relay. The circuit containing the soft start coil of the soft start relay is connected in series with the soft start control normally open contact of the soft start control relay. The adjustment switch also includes a soft start position, which is connected in series in the circuit containing the soft start control coil of the soft start control relay. The soft start control relay is a time-delay type relay. When the adjustment switch is in the soft start position, the soft start control coil is energized, the soft start control normally open contact closes after a delay, and the soft start normally open contact closes. The branch containing the soft start normally open contact bypasses the branch containing the soft start resistor.

[0057] Specifically, the rectifier uses a rectifier bridge.

[0058] Specifically, a capacitor is also connected to the output of the rectifier, which is used to power the high-voltage DC power supply board under test.

[0059] Specifically, the output terminal of the capacitor used to power the tested high-voltage DC power supply board is connected in series with a discharge branch. This discharge branch is connected in parallel with the tested high-voltage DC power supply board so that it can be activated after the tested high-voltage DC power supply board has finished testing. The discharge branch includes a series discharge resistor and a discharge switch for controlling the activation of the discharge branch. Compared to existing manual discharge, discharge via the discharge branch is safer and more reliable.

[0060] Specifically, the control switch uses the normally open contact of the winding relay, and the normally closed contact of the winding relay is connected in series in the discharge branch. The discharge switch uses the normally open contact of the discharge relay to achieve interlocking between discharge and transformer voltage conversion, which is safer and more reliable.

[0061] Specifically, a voltmeter is connected in parallel to the output terminal of the capacitor to measure the voltage across the capacitor.

[0062] Specifically, the primary side of the transformer is also connected in parallel with a heat dissipation branch for cooling the devices in the test apparatus. This heat dissipation branch includes a cooling fan connected in series and a heat dissipation switch for controlling the power supply to and from the cooling fan.

[0063] Specifically, a power indicator light is also connected in parallel on the primary side of the transformer to determine the AC power supply status by the on / off state of the power indicator light.

[0064] Specifically, the device also includes a digital voltmeter, which is connected in parallel to the output terminal of the high-voltage DC power supply board under test to measure its output voltage.

[0065] The following section will provide a more detailed description of the test device, using a transformer with two different secondary windings and a test device suitable for high-voltage DC power supply boards that uses a rotary switch to achieve soft start and voltage conversion.

[0066] To improve the testing efficiency of the high-voltage DC power supply board under test, existing technologies are optimized, specifically by adopting the following methods: Figure 2 The device shown is a test apparatus for high-voltage DC power supply boards, which can greatly improve the testing efficiency of DC power supply boards.

[0067] like Figure 2 The specific design of the test apparatus shown is as follows:

[0068] (1) The testing device has a live display function and a heat dissipation function: the busbars N and L are connected to a 220VAC power supply. After the 220VAC power supply is supplied, the power indicator LED1 lights up to realize the live display; after the miniature power circuit breaker (not shown in the figure) is closed, the built-in cooling fan (shown in the figure) runs directly to dissipate heat from the step-up transformer, rectifier module, capacitor and other components in the testing device. The testing device is also equipped with an air switch QF (abbreviated as air switch) for overload and short circuit protection. The air switch QF is located between the branch where the miniature power circuit breaker and the cooling fan are connected in series, the two ends of the power indicator LED1 and the primary side of the step-up transformer connected in parallel, and the busbars N and L.

[0069] (2) The test device has three gear switching functions: 0V, 300VDC and 900VDC. The output of different secondary windings (U2<220V>, U3<630V>, where 220V and 630V refer to the output voltages of U2 and U3 respectively) of the step-up transformer is controlled by the changeover switch SB1 (i.e. the three-position rotary switch SB1 with lockout in the figure). After rectification by the rectifier bridge composed of diodes T1, T2, T3 and T4, the DC voltage can be switched quickly and the process is safe and reliable.

[0070] (3) The testing device has a DC output voltage discharge function: the discharge control circuit is interlocked with the DC output voltage and controlled by a jog reset button to avoid accidental discharge activation. The discharge control circuit includes a discharge switch with a normally open contact of relay KM6. The discharge switch is connected in series with a discharge resistor, the normally closed contact of relay KA1, and the normally closed contact of relay KA2. The normally open contact of relay KA1 is located in the control circuit (powered by 24V) of one of the secondary windings of the transformer, and the normally open contact of relay KA2 is located in the control circuit (powered by 24V) of the other secondary winding. When the normally open contact of relay KA1 is closed, the corresponding branch of the secondary winding is energized, and the transformer performs the corresponding voltage conversion. The DC voltage is then output after rectification by a rectifier bridge, and the normally closed contact of relay KA1 opens, indicating that the bleeder is not engaged. Similarly, when the normally open contact of relay KA2 closes, the corresponding secondary winding branch is energized, the transformer performs the corresponding voltage conversion, and the DC voltage is output after rectification by a rectifier bridge, with the normally closed contact of relay KA2 opening again, indicating that the bleeder is not engaged. When the normally open contacts of relays KA1 and KA2 are open, and the normally open contact of relay KM6 is closed, the bleeder is engaged. A bleeder control rotary switch SB2 is connected in series in the circuit containing the coil of relay KM6. The bleeder control rotary switch SB2 uses a momentary reset button to avoid accidental activation of the bleeder. The two secondary windings of the transformer are connected in parallel. The primary winding of the transformer is connected to the power input terminal of the device via a micro-break switch. After the circuit breaker QF closes upon device power-up, the control circuit and the transformer are simultaneously energized. At this time, operating the changeover switch SB1 allows for direct and rapid switching of the DC voltage.

[0071] (4) The testing device has a digital DC voltage display function: after switching, the current output DC voltage of the device can be read intuitively. The DC voltage output port is easy to maintain and wire. The device casing is reliably grounded and easy to carry. Specifically, a capacitor is connected to the output end of the rectifier bridge. This capacitor is used to power the high-voltage DC power supply board under test. A voltmeter is connected in parallel to the output end of the capacitor to measure the voltage across the capacitor. The voltmeter has a digital DC voltage display function to read the current output DC voltage intuitively.

[0072] The specific working principle of this device is as follows:

[0073] Check that the DC conversion switch SB1 is in the stop position and the AC power switch (not shown in the figure) is in the off position. Connect the DC output terminal of the device to the input terminal of the DC high voltage power supply board under test. Connect the device to an external 220VAC AC power supply, and ensure that the external power supply is on. The device's power indicator LED1 should be lit.

[0074] Close the AC power switch, select the corresponding DC voltage level using the changeover switch SB1, and the corresponding DC contactor will engage, charging the DC bus through the soft-start resistor. The time-delayed closing relay KT actuates (1s-2s), energizing the coil of relay KM5. This closes the normally open contact of relay KM5, which acts as the soft-start switch. The soft-start switch and soft-start resistor are connected in parallel. The closed soft-start switch bypasses the soft-start resistor, thus bypassing the DC soft-start resistor, allowing the device to output normally.

[0075] The corresponding DC voltage;

[0076] After the test, set the DC voltage conversion switch SB1 to the stop position and jog the "discharge button" of the device.

[0077] (With interlocking logic, the discharge circuit is ineffective during DC voltage output). After the DC voltmeter displays 0V, disconnect the AC input power supply and disconnect the DC output terminal wiring to complete the test.

[0078] The beneficial effects of this plan are:

[0079] Using AC220V as the input power supply, the transformer outputs two AC channels. The selector switch SB1 controls the output DC voltage range (low voltage range, high voltage range). After rectification and filtering, the output DC voltage supplies power to the input terminal of the high voltage power supply board. There is no need to operate the voltage regulator to adjust the voltage, which can realize DC power supply testing, save the output voltage adjustment time, and improve the power safety of the board testing.

[0080] Taking into account production capacity, testing efficiency, and historical testing data, the testing time has been reduced from 20 minutes to 6 minutes, improving efficiency by 70%. This translates to a saving of 7 yuan in labor costs per board, and an annual saving of 7*N yuan in labor costs.

Claims

1. A testing device suitable for high-voltage DC power supply boards, characterized in that, The device includes a transformer. The primary side of the transformer is used to connect to an external AC power source. The secondary side of the transformer includes at least two different secondary windings connected in parallel. Each parallel branch containing a secondary winding is connected in series with a control switch to control the conduction of its parallel branch and enable the transformer to perform voltage conversion for any parallel branch. The output terminals of the transformer are also connected to a rectifier to convert AC power to DC power, so as to output the DC voltage required for testing the high-voltage DC power supply board under test. The number of turns in the secondary winding is determined based on the voltage required for testing the high-voltage DC power supply board and the voltage conversion ratio determined by the AC power supply.

2. The test device suitable for use with a high voltage DC power panel of claim 1, wherein, The control switch uses the normally open contact of the winding relay. The normally open contact of the switching control relay is connected in series in the circuit where the winding coil of the winding relay is located. The switching control coil of the switching control relay is connected in series in the circuit where the switching regulation switch is located. When the switching regulation switch is closed, the switching control coil connected in series with the switching regulation switch is energized, and the corresponding normally open contact of the switching control is closed. In turn, the winding coil connected in series with the normally open contact of the switching control is energized, and the corresponding normally open contact of the winding is closed. The parallel branch where the normally open contact of the winding is located is connected, so that the transformer can perform voltage conversion of the parallel branch.

3. The testing device suitable for use with a high voltage direct current power panel according to claim 1 or 2, characterized in that, A soft start module is connected in series between the output terminal of the transformer and the rectifier. The soft start module includes a soft start switch connected in parallel and a soft start resistor for limiting the starting current.

4. The test device suitable for use with a high voltage DC power panel of claim 3, wherein, The soft start switch uses the soft start normally open contact of the soft start relay. The soft start coil of the soft start relay is connected in series with the soft start control normally open contact of the soft start control relay. The soft start control coil of the soft start control relay is connected in series with the soft start regulating switch. The soft start control relay is a time-delay type relay. When the soft start regulating switch is closed, the soft start control coil is energized, the soft start control normally open contact closes after a delay, and the soft start normally open contact closes. The branch where the soft start normally open contact is located bypasses the branch where the soft start resistor is located.

5. The testing device for high-voltage DC power supply boards according to claim 1, characterized in that, A capacitor is also connected to the output of the rectifier, which is used to power the high-voltage DC power supply board under test.

6. The testing device for high-voltage DC power supply boards according to claim 5, characterized in that, The output terminal of the capacitor used for power supply connection to the high voltage DC power supply board under test is also connected in series with a discharge branch. The discharge branch is used to connect in parallel with the high voltage DC power supply board under test so that the discharge branch is activated after the high voltage DC power supply board under test is tested. The discharge branch includes a discharge resistor connected in series and a discharge switch for controlling the activation of the discharge branch.

7. The testing device for high-voltage DC power supply boards according to claim 6, characterized in that, The control switch uses the normally open contact of the winding of a winding relay, and the normally closed contact of the winding of the winding relay is connected in series in the discharge branch. The discharge switch uses the normally open contact of the discharge relay.

8. The testing apparatus for high-voltage DC power supply boards according to claim 5 or 6, characterized in that, A voltmeter is connected in parallel to the output terminal of the capacitor to measure the voltage across the capacitor.

9. The testing device for high-voltage DC power supply boards according to claim 1, characterized in that, The primary side of the transformer is also connected in parallel to a heat dissipation branch for cooling the devices in the test apparatus. This heat dissipation branch includes a cooling fan connected in series and a heat dissipation switch for controlling the power supply to and from the cooling fan.

10. The testing device for high-voltage DC power supply boards according to claim 1, characterized in that, The primary side of the transformer is also connected in parallel with a power indicator light, so as to determine the AC power supply status by the on and off status of the power indicator light.

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