Teaching experiment device for measuring power supply equipment's immunity to electric fast transient bursts

Abstract

The application discloses a power supply equipment electric fast transient burst immunity measurement teaching experiment device, which comprises two capacitor coupling clamps, one end of one of the capacitor coupling clamps is connected with a power circuit driving module, and the other end of the capacitor coupling clamp is connected with a main circuit module; the circuit driving module is connected with a power circuit power supply module; the main circuit module is further connected with a main circuit power supply module; one end of the other capacitor coupling clamp is connected with the main circuit module, and the other end of the capacitor coupling clamp is connected with a load module; a high-frequency noise generation module is arranged between the two capacitor coupling clamps; the two capacitor coupling clamps, the main circuit module and the load module are connected with a waveform display module. Through the power supply equipment electric fast transient burst immunity measurement teaching experiment device, college electromagnetic compatibility experiment teaching can be carried out, and the ability of students to solve engineering practical problems by combining electromagnetic compatibility theoretical knowledge can be better cultivated.

Description

Technical Field

[0001] This invention belongs to the technical field of experimental teaching device development for electrical engineering majors in higher education institutions, and relates to an experimental teaching device for measuring the immunity of electrical fast transient pulses and bursts. Background Technology

[0002] Current teaching experimental devices for measuring the immunity of power supply equipment via electrical fast transients and bursts (EFTs) serve as experimental teaching tools. They simulate the changes in the operating state of the circuit under test (DUT) when subjected to electromagnetic interference by injecting EFTs into the DUT, and then measure the EHF performance of the DUT through experiments. This teaching experimental device can be used by students and researchers in universities to investigate abnormal operation problems of switching power supply circuits under EFT interference. However, when injecting interference into the DUT circuit through the interference generation module, current teaching experimental devices cannot determine the intensity of the EFT interference emitted by the interference generation module and the interference coupled to the DUT. They cannot clarify the magnitude of the injected EFT interference when the DUT experiences abnormal operation due to interference, and cannot quantitatively evaluate and analyze the EHF performance of the switching power supply under test. Furthermore, most current EMC (electromagnetic compatibility) experimental teaching devices in universities are biased towards theoretical verification, with few experimental teaching devices specifically for testing the EHF system performance of the DUT. In addition, most of the test objects in current electromagnetic compatibility experimental teaching devices are simulated rather than real test devices, and the types of test devices are relatively limited. The test objects can only be tested under a single working condition and cannot simulate the anti-interference performance of various test system devices under different working conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment. This device solves the problem that current teaching experimental devices for measuring electrical fast transient / burst immunity cannot quantitatively couple the electrical fast transient / burst interference emitted by the interference generation module to the device under test, thus making it impossible to know the voltage or current intensity of the coupled electrical fast transient / burst interference on the device under test.

[0004] The technical solution adopted in this invention is a teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment, comprising two capacitive coupling clips. One capacitive coupling clip has its two ends connected to a power circuit drive module and a main circuit module, respectively. The drive module is connected to the power circuit power supply module, and the main circuit module is also connected to the main circuit power supply module. The other capacitive coupling clip has its two ends connected to the main circuit module and a load module, respectively. A high-frequency noise generation module is installed between the two capacitive coupling clips. Both capacitive coupling clips, the main circuit module, and the load module are all connected to a waveform display module. A high-voltage differential probe is installed on the connection line between the two capacitive coupling clips, the load module, and the waveform display module. A low-voltage differential probe is installed on the connection line between the main circuit module and the waveform display module.

[0005] The invention is further characterized by:

[0006] The load module is a resistor R, a capacitor C, or an inductor L.

[0007] The main circuit module uses a half-bridge circuit composed of IGBT switching devices, a single-phase full-bridge circuit composed of IGBT switching devices, or a three-phase full-bridge circuit composed of IGBT switching devices to power the DC voltage U output by the main circuit power module. DC It converts to AC power to supply power to the load module.

[0008] An immunity test is conducted on the equipment's signal by transmitting voltage and current from an electrical fast transient (EFT) pulse group generated by a high-frequency noise generation module via near-field radiation coupling using a capacitive coupling clamp. The EFT interference voltage U emitted by the high-frequency noise generation module is... EFT The waveform (t) should satisfy equation (1), and the interference current I EFT (t) should satisfy the expression shown in equation (2):

[0009]

[0010] Where, k v The peak value of the interference voltage; v1 is a constant; k EFT τ1 is the correction factor for the peak value of the interference voltage; nEFT is the number of interference pulses in one cycle; τ1 is the rise time of the interference voltage; τ2 is the pulse width duration of the interference voltage.

[0011]

[0012] Where I is the peak value of the interference current; η is the correction factor for the peak value of the interference current; T1 is the rise time of the interference current; and T2 is the pulse width duration of the interference current.

[0013] The power circuit drive module includes a switching control signal generation circuit module and a signal drive amplification circuit module. The switching control signal generation circuit module uses a DSP controller to send switching control signals, which are then amplified by the signal drive amplification circuit module to drive the IGBT device to turn on and off.

[0014] The main component in the signal drive amplifier circuit module is the IGBT gate driver chip, and the power P of the IGBT gate driver chip is... DRV The gate charge Q of the IGBT device gate and input capacitor C iss The decision should be based on the conditions shown in equation (3):

[0015] P DRV ≥2·(Q gate ·f in ·ΔV gate-max +C iss ·f in ·ΔV gate-max 2 (3)

[0016] Among them, f in ΔV represents the switching frequency of the IGBT device. gate-max This is the maximum voltage difference between the high and low levels of the switching transistor drive signal;

[0017] The drive current I of the IGBT gate driver chip gate-max The gate drive resistance of the IGBT device determines the condition that must be met, as shown in equation (4):

[0018]

[0019] Among them, R int R is the gate drive resistor inside the IGBT device. ext This refers to the external gate drive resistor of the IGBT device.

[0020] The capacitive coupling clip is a capacitor. This capacitor needs to be charged to obtain the interference voltage U on the capacitive coupling clip. N The expression for (t) is shown in equation (5):

[0021]

[0022] Where Q is the total charge on the capacitive coupling clip, and C eq Let I be the equivalent coupling capacitance of the capacitive coupling clip, T be the charging time of the interference current, and I be the capacitance of the coupling clip. d The steady-state current value, t w It is the duration of the interference pulse current;

[0023] The interference voltage on the capacitive coupling clip acts on the interfered drive signal through capacitive coupling, thus generating a coupled interference voltage U on the drive signal. c As shown in equation (6):

[0024]

[0025] Where ω is the angular frequency of the IGBT device, f is the operating frequency of the IGBT device, and Z... L1 Z is the impedance of the capacitive coupling clip. L2 The impedance of the main circuit module, Z s1 Z represents the impedance of the high-frequency noise generation module. s2 The impedance of the power circuit drive module;

[0026] When the interference pulse emitted by the high-frequency noise generation module is a voltage wave, the coupling interference voltage U generated on the drive signal... c As shown in equation (7):

[0027]

[0028] The equivalent coupling capacitance of the capacitor coupling clip is composed of three capacitors connected in parallel: the equivalent capacitance C1 between metal plate A and the drive signal line, the equivalent capacitance C2 between metal plate B and the drive signal line, and the equivalent capacitance C3 between the lower metal plate and the drive signal. Since metal plate A and metal plate B are symmetrical structures, the capacitances C1 and C2 are equal. The expressions for capacitances C1, C2, and C3 are shown in equations (8) and (9):

[0029]

[0030]

[0031] Where, ε r denoted as the relative permittivity of air, w as the linewidth of the drive signal line, l as the line length of the drive signal line (which is the same as the length of the capacitive coupling clip), k as the electrostatic constant, and θ as the angle formed between metal plate A and metal plate B.

[0032] Due to the equivalent coupling capacitance C of the capacitive coupling clip eq It is composed of C1, C2, and C3 connected in parallel, from which we can obtain C. eq The expression is shown in equation (10):

[0033]

[0034] The width b of the lower metal plate is shown in equation (11):

[0035]

[0036] Where a is the width of metal plate A, and the width of metal plate A is equal to the width of metal plate B.

[0037] The beneficial effects of this invention are as follows: The teaching experimental device for measuring the electromagnetic immunity of power supply equipment proposed in this invention starts from the mechanism of electromagnetic interference generated by the interference generation module and the coupling interference on the device under test. By designing the coupling angle and distance between the metal plates of the capacitor coupling clamp in the device, the parameter values ​​between the size of the coupling capacitor and the coupling interference can be quantitatively obtained. This allows for more accurate measurement of the electromagnetic immunity threshold of the device under test. Furthermore, it enables students and researchers to better understand the electromagnetic immunity mechanism of the device under test when subjected to electromagnetic interference and to clarify the coupling path of the interference. Attached Figure Description

[0038] Figure 1 This is a structural block diagram of the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention;

[0039] Figure 2 This is a schematic diagram of the implementation principle of the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention;

[0040] Figure 3 This is a schematic diagram of the capacitive coupling clip in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention.

[0041] Figure 4 This is a schematic diagram of the parasitic capacitance distribution between the capacitive coupling clamp and the drive signal line in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention.

[0042] Figure 5 This is a measured waveform of an electrical fast transient / burst immunity test device on a capacitive coupling clamp in the teaching experimental apparatus for measuring the electrical fast transient / burst immunity of the power supply equipment of this invention.

[0043] Figure 6 This is a measured waveform diagram of the superimposed interference pulse on the IGBT device drive signal in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention.

[0044] Figure 7 This is a measured waveform diagram of superimposed interference pulses on the load module in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention.

[0045] In the diagram, 2-1. Power circuit power supply module, 2-2. Power circuit drive module, 2-3. Capacitor coupling clip, 2-4. Main circuit module, 2-5. Main circuit power supply module, 2-6. Load module, 2-7. High-frequency noise generation module, 2-8. Waveform display module, 2-9. High voltage differential probe, 2-10. Low voltage differential probe;

[0046] 3-1. Metal electrode A, 3-2. Metal electrode B, 3-3. Lower metal electrode, 3-4. Insulating base, 3-5. Interference signal input terminal, 3-6. Rotary valve;

[0047] 4-1. Drive signal line, 4-2. Signal line slot. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] The structural block diagram of the teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment of the present invention is as follows: Figure 1 As shown, the device includes a power circuit power supply module 2-1, a power circuit drive module 2-2, two capacitor coupling clips 2-3 to prevent interference coupling between the drive signal line and the main circuit load line, a main circuit module 2-4, a main circuit power supply module 2-5, a load module 2-6, a high-frequency noise generation module 2-7, a waveform display module 2-8, three high-voltage differential probes 2-9, and two low-voltage differential probes 2-10.

[0051] Figure 2 This is a schematic diagram of the implementation principle of the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of the present invention. The 220V AC power supplied by the mains is converted to DC power by the power circuit power module 2-1 and then connected to the power circuit drive module 2-2. The power circuit drive module 2-2 is connected to the main circuit module 2-4 via the drive signal line 4-1. The main circuit module 2-4, load module 2-6, and main circuit power module 2-5 form the main circuit loop. Two capacitive coupling clips 2-3 are placed at the drive signal line 4-1 and the main circuit load line (connected to the load module 2-6) respectively to provide interference coupling to the drive signal line 4-1. Three high-voltage differential probes 2-9 and two low-voltage differential probes 2-10 are connected to the waveform display module 2-8, and the signal waveform at the required location is measured through the three high-voltage differential probes 2-9 and the two low-voltage differential probes 2-10.

[0052] Figure 3This is a schematic diagram of the capacitive coupling clip in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of this invention. The two capacitive coupling clips 2-3 have identical structures. Each capacitive coupling clip 2-3 includes a metal plate A3-1, a metal plate B3-2, a lower metal plate 3-3, an insulating base 3-4, an interference signal input terminal 3-5, and three rotary valves 3-6. The widths of metal plates A3-1 and B3-2 are equal, both being 'a'. The width of the lower metal plate 3-3 is 'b'. The heights of metal plates A3-1 and B3-2 from the lower metal plate 3-3 are 'h'. The length of the entire capacitive coupling clip device 2-3 is 'l'.

[0053] Figure 4 This is a schematic diagram of the parasitic capacitance distribution between the capacitive coupling clamp 2-3 and the drive signal line 4-1 in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of this invention. The drive signal line 4-1 is fixed on the signal line slot 4-2, and the height of the signal line slot 4-2 is adjusted so that the drive signal line 4-1 is at the center of the capacitive coupling clamp 2-3. The metal plates A3-1 and B3-2 form two parasitic capacitances C1 and C2 with equal capacitance between themselves and the drive signal line 4-1, and the lower metal plate 3-3 forms another parasitic capacitance C3 between itself and the drive signal line 4-1.

[0054] This invention provides a teaching experimental device for measuring the electromagnetic interference immunity of power supply equipment. A power circuit power module 2-1 converts single-phase 220V AC mains power into DC power of a certain amplitude, which is then connected to a power circuit drive module 2-2 to power it. The power circuit drive module 2-2 sends drive signals through drive signal line 4-1 to the main circuit module 2-4 to control the on / off switching of IGBT devices. By sending different numbers of drive signals to control the corresponding IGBT devices in the main circuit, different types of bridge circuit structures are formed, allowing students to explore the electromagnetic interference immunity characteristics of different main circuit topologies. The main circuit power module 2-5 can output DC power of different amplitudes to the main circuit module 2-4. By controlling the on / off switching of the IGBTs in the main circuit, the electrical energy is converted into DC or AC power and then transmitted to the load module 2-6. The load module 2-6 is composed of passive components such as inductors, capacitors, and resistors, allowing students to observe the different immunity performance of the load to electromagnetic interference under different load characteristics. A capacitor coupling clip is installed at two locations: the drive signal line 4-1 and the main circuit load line. The two capacitor coupling clips can work simultaneously or only one of them can work. An electrical fast transient pulse group interference voltage is emitted by the high-frequency noise generation module 2-7 and transmitted to the capacitor coupling clip. The interference voltage is coupled to the drive signal line and the main circuit load line through capacitive coupling. The signal waveform at the desired observation location is acquired by three high-voltage differential probes and two low-voltage differential probes and transmitted to the waveform display module 2-8 to reproduce the signal waveform.

[0055] Example 2

[0056] In this invention, the teaching experimental device for measuring the immunity to electrical fast transient pulses and pulse groups of power supply equipment is designed to enable students to clearly understand and observe the different immunity performance of loads to electromagnetic interference under different load characteristics, such as resistive, capacitive, and inductive loads. This invention selects one of the following as the load type: resistor R, capacitor C, or inductor L. By observing the output voltage waveform on the load, students can understand the immunity mechanism of different types of loads to electromagnetic interference. In this embodiment, a 50W aluminum-cased resistor with a resistance of 100Ω manufactured by VISHAY is selected as the resistive load R; a 100V film capacitor with a capacitance of 100nF manufactured by KNSCHA is selected as the capacitive load C; and a 5A magnetic ring inductor with an inductance of 10uH manufactured by Sunltech is selected as the inductive load L.

[0057] Example 3

[0058] Since load module 2-6 contains both AC and DC loads, the DC voltage U output from main circuit power module 2-5 needs to be converted through main circuit module 2-4.DC It converts the current to AC to power the AC load. Main circuit module 2-4 uses IGBTs (Insulated Gate Bipolar Transistors) to form a half-bridge, single-phase full-bridge, or three-phase full-bridge circuit.

[0059] By employing different types of bridge circuit structures, students can explore the impact of electromagnetic interference on the conduction and turn-off processes of IGBT devices at different positions in different bridge arms, thereby affecting the operating state of load module 2-6. Since the bridge circuit is composed of IGBT switching devices, it is necessary to select appropriate IGBT models through parameter design. If the voltage U output by the main circuit power module 2-5... DC The rated voltage U of the IGBT device is 311V. gn The condition that must be met is U gn ≥2·U DC Therefore, the rated voltage of IGBT devices should be greater than or equal to 622V; when the load is an inductive load with a rated current of 5A and an inductance of 10uH, the rated current of the IGBT device is generally required to meet the condition I. gn ≥1.5·I LOAD Therefore, the rated current of the IGBT device should be greater than or equal to 7.5A. Based on the above analysis, the IGBT device selected can be the Infineon IKW25T120, with a rated voltage of 1200V and a rated current of 25A.

[0060] Example 4

[0061] Since the effective value of the single-phase AC mains power input is 220V, which exceeds the rated voltage of the load, it can easily cause overvoltage damage to the load equipment. Therefore, it is necessary to use the main circuit power module 2-5 to step down the 220V AC power and convert it into DC power with an adjustable output range. By changing the input voltage of the main circuit power module 2-5, students can also conduct teaching experiments to study the effects of electromagnetic interference on the load under different operating conditions with different input voltages. Therefore, the main circuit power module 2-5 selected is the HY-PM 350-3 programmable isolated DC power supply from Hangyu, with a rated voltage of 0-350V and a rated current of 0-3A.

[0062] Example 5

[0063] The power circuit driver module 2-2 consists of two circuit modules: a switching transistor control signal generation circuit module and a signal drive amplification circuit module. The switching transistor control signal generation circuit module uses a TI TMS320F28335 DSP controller to generate the switching transistor control signal. Since the switching transistor control signal generated by the switching transistor control signal generation circuit module has relatively low power and cannot meet the drive power requirements of the IGBT device, the signal drive amplification circuit module is needed to amplify the low-power control signal before driving the IGBT device to turn on and off.

[0064] The main component in the signal drive amplifier circuit module is the IGBT gate driver chip. The selection of the driver chip generally considers two parameters: drive power and peak drive current. The power rating P of the IGBT gate driver chip... DRV The gate charge Q of the IGBT device gate and input capacitor C iss The determination should be based on the conditions shown in equation (1):

[0065] P DRV ≥2·(Q gate ·f in ·ΔV gate-max +C iss ·f in ·ΔV gate-max 2 (1)

[0066] Among them, f in ΔV represents the switching frequency of the IGBT device. gate-max This represents the maximum voltage difference between the high and low levels of the switching transistor drive signal.

[0067] The drive current I of the IGBT gate driver chip gate-max The gate drive resistance of the IGBT device determines the condition it must meet, as shown in equation (2):

[0068]

[0069] Among them, R int R is the gate drive resistor inside the IGBT device. ext This refers to the external gate drive resistor of the IGBT device.

[0070] Based on the above analysis, when the set switching frequency is 5kHz, if the selected IGBT device is Infineon's IKW25T120 IGBT device, its gate charge Q can be obtained from the datasheet. gate The input capacitor is 155nC. iss It has a voltage rating of 1860pF and an internal gate drive resistor R. intThe external gate drive resistor R is 8Ω. ext The impedance is 10Ω. Calculations show that the driving power P of the IGBT gate driver chip is... DRV The drive current I should be greater than or equal to 0.06324W. gate-max The current should be greater than or equal to 1.7A. Based on the above analysis, the IGBT gate driver chip can be selected from Avago's ACPL-332J model, which has a drive power of 1.2W and a drive current of 2.5A.

[0071] Example 6

[0072] According to the datasheet for the IGBT device IKW25T120, its gate turn-on / off voltage range is -20V to 20V. The datasheet for the IGBT gate driver chip ACPL-332J shows that its output low-level voltage is 0.17V and its high-level voltage is V. cc —2V, V cc This refers to the output voltage of the power circuit. Based on the above analysis, the power circuit power module 2-1 can be selected from Mornsun's LM35-20B24 isolated switching power supply, which has an output voltage of 24V DC and an output current of 1.5A.

[0073] Example 7

[0074] According to the standards GB / T 17626.4-2018 and IEC 62305-1, when conducting electrical fast transient / burst immunity tests on the equipment under test, the voltage and current of the electrical fast transient / burst generated by the high-frequency noise generator module 2-7 must be transmitted through the capacitive coupling clamp 2-3 in a near-field radiation coupling manner to test the equipment's signal immunity. The electrical fast transient / burst interference voltage U emitted by the high-frequency noise generator module 2-7... EFT (t) The waveform should satisfy equation (3), and the interference current I EFT (t) should satisfy the expression shown in equation (4):

[0075]

[0076] Where, k v The peak value of the interference voltage; v1 is a constant of 0.92; k EFT τ1 is the correction factor for the peak value of the interference voltage; nEFT is the number of interference pulses in one cycle; τ1 is the rise time of the interference voltage; and τ2 is the pulse width duration of the interference voltage.

[0077]

[0078] Where I is the peak value of the interference current; η is the correction factor for the peak value of the interference current; T1 is the rise time of the interference current; and T2 is the pulse width duration of the interference current.

[0079] In summary, the high-frequency noise generation modules 2-7 can be selected from the INS 400 high-frequency noise simulator manufactured by 3ctest.

[0080] Example 8

[0081] Since the signal grounds of the main circuit module 2-4 and the power circuit drive module 2-2 are different, to prevent abnormal waveform acquisition due to ground interference during signal acquisition of the main circuit module 2-4 and the power circuit drive module 2-2, and considering the significant difference in voltage levels between the two modules, a high-voltage differential probe 2-9 is required to acquire the signal waveform of the main circuit module 2-4, and a low-voltage differential probe 2-10 is required to acquire the signal waveform of the power circuit drive module 2-2. Therefore, the high-voltage differential probe 2-9 can be a Tektronix P5210A model, and the low-voltage differential probe 2-10 can be a Tektronix TDP1500 model.

[0082] Example 9

[0083] The signal waveform acquired by the probe needs to be reproduced on the screen through the waveform display module 2-8. Simultaneously, the waveform display module 2-8 should be able to acquire waveforms from four channels in each experiment, allowing for comparison of the effects of electromagnetic interference on different locations of the main circuit module 2-4 and the power circuit drive module 2-2. This enables students to clearly observe the circuit's operating status under electromagnetic interference. Therefore, a Tektronix MSO56B oscilloscope can be used for the waveform display module 2-8.

[0084] Example 10

[0085] Since the electrical fast transient pulse group interference emitted by the high-frequency noise generation module 2-7 is coupled to the drive signal through capacitive coupling, this invention needs to design a suitable capacitive coupling clip 2-3. The width a of metal plate A3-1 and metal plate B3-2, the width b of the lower metal plate 3-3, and the phase distance h between them are designed to obtain a suitable coupling capacitor, so that the interference pulse can be coupled to the drive signal and the load output signal under different conditions.

[0086] The coupling mechanisms between different types of interference pulses and driving signals are as follows:

[0087] Before designing the parameters of capacitor coupling clips 2-3, it is necessary to clarify the coupling mechanism between different types of interference pulses and driving signals, so as to design the equivalent coupling capacitor between the two signals. The required parameters of the capacitor coupling clip can be designed based on the size of the equivalent coupling capacitor. When the interference emitted by the high-frequency noise generation module is a current wave, since the capacitor coupling clip is essentially a capacitor, it needs to be charged to obtain the interference voltage U on the capacitor coupling clip. N The expression for (t) is shown in equation (5):

[0088]

[0089] Where Q is the total charge on the capacitive coupling clip, and C eq Let I be the equivalent coupling capacitance of the capacitive coupling clip, T be the charging time of the interference current, and I be the capacitance of the coupling clip. d The steady-state current value, t w It is the duration of the interference pulse current.

[0090] The interference voltage on capacitive coupling clips 2-3 acts on the interfered drive signal through capacitive coupling, thus generating a coupled interference voltage U on the drive signal. c As shown in equation (6):

[0091]

[0092] Where ω is the angular frequency of the IGBT device, f is the operating frequency of the IGBT device, and Z... L1 Z is the impedance of the capacitive coupling clip. L2 The impedance of the main circuit module, Z s1 Z represents the impedance of the high-frequency noise generation module. s2 This is the impedance of the power circuit drive module.

[0093] When the interference pulse emitted by the high-frequency noise generation module 2-7 is a voltage wave, the coupling interference voltage U generated on the drive signal... c As shown in equation (7):

[0094]

[0095] When coupled interference voltage is superimposed on the drive signal, it will cause a voltage spike at different high or low levels of the drive signal, which will affect the normal turn-on and turn-off process of the IGBT device. If the interference pulse is superimposed on the high level of the drive signal, it will cause the voltage of the drive signal to exceed the gate withstand voltage of the switching device, resulting in gate breakdown and damage. If the interference pulse is superimposed on the low level of the drive signal, when the amplitude of the interference pulse exceeds the high level, it will cause the switching device to be falsely turned on, forming a path that leads to a short circuit in the load. Therefore, the size of the equivalent coupling capacitor can be designed according to the maximum gate withstand voltage and turn-on voltage of the IGBT, and the equivalent coupling capacitor C can be used to determine the appropriate capacitance. eq The size of the capacitor coupling clip is used to design its dimensions.

[0096] The design process for the 2-3 dimensional parameters of the capacitor coupling clip is as follows:

[0097] According to the theory of parallel plate capacitors, the equivalent coupling capacitance of capacitor coupling clip 2-3 is composed of three capacitors connected in parallel: the equivalent capacitance C1 between metal plate A3-1 and drive signal line 4-1, the equivalent capacitance C2 between metal plate B3-2 and drive signal line 4-1, and the equivalent capacitance C3 between lower metal plate 3-3 and drive signal line 4-1. Since metal plate A3-1 and metal plate B3-2 are symmetrical structures, the capacitances C1 and C2 are equal in size. The expressions for capacitances C1, C2, and C3 are shown in equations (8) and (9):

[0098]

[0099]

[0100] Where, ε r Let be the relative permittivity of air, i.e., 1.00053; w be the linewidth of drive signal line 4-1; l be the line length of drive signal line 4-1 (equal to the length of the entire capacitor coupling clamp device 2-3); and k be the electrostatic constant, i.e., 9 × 10⁻⁶. 9 N·m 2 / C 2 θ is the angle formed between metal plate A3-1 and metal plate B3-2.

[0101] Due to the equivalent coupling capacitance C of capacitive coupling clamps 2-3 eq It is composed of C1, C2, and C3 connected in parallel, from which we can obtain C. eq The expression is shown in equation (10):

[0102]

[0103] The equivalent coupling capacitance C was determined using equation (10). eqAfter determining the size, the combined formula (8-10) can be used to design the width a of the metal plates A3-1 and B3-2 of the capacitor coupling clamp 2-3 and the phase distance h between the metal plates A3-1, B3-2 and the lower metal plate 3-3.

[0104] After h is designed, the width b of the lower metal plate 3-3 can be designed using the trigonometric transformation theory. The width b of the lower metal plate 3-3 is shown in equation (11):

[0105]

[0106] Figure 5 This is a measured electrical fast transient / burst (EFT) waveform on a capacitive coupling clamp in the teaching experimental device for measuring the EFT immunity of the power supply equipment of this invention. An interference pulse with an amplitude of 1000V and a period of 20ms is injected into the capacitive coupling clamp 2-3 via a high-frequency noise generation module 2-7. The waveform of the interference pulse on the capacitive coupling clamp 2-9 is measured using a high-voltage differential probe 2-9, and the result is shown below. Figure 5 The interference pulse voltage waveform shown is 988V, and the measured interference pulse voltage amplitude is 19.96ms.

[0107] Figure 6 This is a measured waveform diagram of the IGBT device drive signal superimposed with an interference pulse in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of this invention. The three waveforms from top to bottom are the interference pulse voltage waveform, the voltage waveform of drive signal 1, and the voltage waveform of drive signal 2. Drive signal 1 has an amplitude of 3.52V and a frequency of 5.67kHz; drive signal 2 has an amplitude of 8.20V and a frequency of 5.67kHz. When the drive signal line is coupled with an interference pulse with an amplitude of 988V and a period of 19.96ms, a spike pulse voltage with an amplitude of 14.4V is coupled during the low-level phase of drive signal 1 and the high-level phase of drive signal 2.

[0108] Figure 7 This is a measured waveform diagram of an interference pulse superimposed on the load module in the teaching experimental device for measuring the electrical fast transient / burst immunity of the power supply equipment of this invention. The two waveforms from top to bottom are the interference pulse voltage waveform and the load line output voltage waveform, respectively. The load line output voltage amplitude is 28.6V and the period is 176.1μs. When the load line is coupled with an interference pulse with an amplitude of 988V and a period of 19.96ms, a spike pulse voltage with an amplitude of 33V will appear in the low-level phase of the load line output voltage.

[0109] This invention presents a teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment, which closely integrates experimental teaching with engineering practice. It can be used in universities to conduct radiated electromagnetic interference (EMI) immunity experiments for electrical engineering students studying electromagnetic compatibility (EMC) courses, deepening students' understanding of the practical application of EMC theory. Furthermore, this invention can simulate the testing environment of an enterprise testing site for EMC performance experiments on system equipment, giving students a clearer understanding of how EMC testing is conducted in enterprises. By using this power supply equipment's EMC immunity measurement teaching experimental device for university EMC experimental teaching, students' ability to solve practical engineering problems by combining EMC theoretical knowledge can be better cultivated.

[0110] This invention provides a teaching experimental device for measuring the immunity of power supply equipment to electrical fast transients and bursts. It utilizes the coupling mechanism between electrical fast transient and burst interference generated by the interference generation module and induced interference on the device under test. By changing the coupling angle and distance between the metal plates of the capacitor coupling clamp in the device, and thus adjusting the coupling capacitance, it can quantitatively couple electrical fast transient and burst interference onto the device under test, rather than obtaining it through trial and error. This allows students and researchers to qualitatively and quantitatively study the disturbance mechanism and coupling path of the device under test when subjected to electrical fast transient and burst interference.

Claims

1. A teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment, characterized in that: The system includes two capacitive coupling clips (2-3). One capacitive coupling clip (2-3) is connected at both ends to a power circuit drive module (2-2) and a main circuit module (2-4), respectively. The power circuit drive module (2-2) is connected to a power circuit power supply module (2-1), and the main circuit module (2-4) is also connected to a main circuit power supply module (2-5). The other capacitive coupling clip (2-3) is connected at both ends to a main circuit module (2-4) and a load module (2-6), respectively. A high-frequency noise generation module (2-7) is located between the two capacitive coupling clips (2-3). The two capacitive coupling clips (2-3), the main circuit module (2-4), and the load module... Blocks (2-6) are all connected to the waveform display module (2-8). High-voltage differential probes (2-9) are installed on the connection lines between the two capacitive coupling clips (2-3), the load module (2-6), and the waveform display module (2-8). Low-voltage differential probes (2-10) are installed on the connection lines between the main circuit module (2-4) and the waveform display module (2-8). The voltage and current of the electrical fast transient pulse group emitted by the high-frequency noise generation module (2-7) are used to conduct an immunity test on the equipment signal via near-field radiation coupling through the capacitive coupling clips. The electrical fast transient pulse group interference voltage emitted by the high-frequency noise generation module (2-7) is... The waveform should satisfy equation (1), and the interference current It should satisfy the expression shown in equation (2): （1） in, k v This represents the peak value of the interference voltage. v 1 is a constant; k EFT nEFT is the correction factor for the peak value of the interference voltage; nEFT is the number of interference pulses in one cycle. The rise time of the interference voltage; The pulse width duration of the interference voltage; （2） in, I This represents the peak value of the interference current. It is a correction factor for the peak value of the interference current; T 1 represents the rise time of the interference current; T 2 represents the pulse width and duration of the interference current; When the interference emitted by the high-frequency noise generation module is a current wave, the capacitor coupling clip (2-3) is a capacitor. This capacitor needs to be charged to obtain the interference voltage on the capacitor coupling clip (2-3). The expression is shown in equation (3): （3） in, t w It is the pulse width and duration of the interference pulse current. I d It is the duration of the steady-state current. C eq This is the equivalent coupling capacitance of the capacitive coupling clip; The interference voltage on the capacitive coupling clip (2-3) acts on the interfered driving signal through capacitive coupling, thus generating a coupled interference voltage on the driving signal. As shown in equation (4): （4） in, The angular frequency of the IGBT device. f The operating frequency of the IGBT device. Z L1 The impedance of the capacitive coupling clip (2-3) is... Z L2 The impedance of the main circuit module (2-4) Z s1 The impedance of the high-frequency noise generation module (2-7) is... Z s2 The impedance of the power circuit drive module (2-2); When the interference pulse emitted by the high-frequency noise generation module (2-7) is a voltage wave, the coupling interference voltage generated on the drive signal... As shown in equation (5): （5） The equivalent coupling capacitance of the capacitor coupling clip (2-3) is composed of three capacitors connected in parallel, namely the equivalent capacitance between the metal plate A (3-1) and the drive signal line. C 1. Equivalent capacitance between metal plate B (3-2) and the drive signal line C 2. The equivalent capacitance between the lower metal plate (3-3) and the driving signal. C 3. Because metal plate A (3-1) and metal plate B (3-2) have a symmetrical structure, the capacitance... C 1 and C The two are equal in size, and the capacitance is... C 1. C 2 and C The expression for 3 is shown in equations (6) and (7): （6） （7） in, is the relative permittivity of air. w For the line width of the drive signal line, l For the length of the drive signal line, k It is the electrostatic constant. The angle formed between metal plate A (3-1) and metal plate B (3-2); Due to the equivalent coupling capacitance of the capacitive coupling clip (2-3) C eq It is by C 1. C 2 and C Three parallel connections are formed, from which we can obtain C eq The expression is shown in equation (8): （8） The width b of the lower metal plate (3-3) is shown in equation (9): （9）； Where a is the width of metal plate A (3-1), and the width of metal plate A (3-1) is equal to the width of metal plate B (3-2).

2. The teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment according to claim 1, characterized in that: The load module (2-6) is a resistor R, a capacitor C, or an inductor L.

3. The teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment according to claim 1, characterized in that: The main circuit module (2-4) adopts a half-bridge circuit composed of IGBT switching devices, a single-phase full-bridge circuit composed of IGBT switching devices, or a three-phase full-bridge circuit composed of IGBT switching devices, to power the DC voltage U output by the main circuit power module (2-5). DC Convert to AC power to supply power to the load modules (2-6).

4. The teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment according to claim 1, characterized in that: The power circuit drive module (2-2) includes a switching control signal generation circuit module and a signal drive amplification circuit module. The switching control signal generation circuit module uses a DSP controller to issue a switching control signal, which is then amplified by the signal drive amplification circuit module to drive the IGBT device to turn on and off.

5. The teaching experimental device for measuring the electrical fast transient / burst immunity of power supply equipment according to claim 4, characterized in that: The main component in the signal drive amplifier circuit module is the IGBT gate driver chip, and the power P of the IGBT gate driver chip is... DRV The gate charge Q of the IGBT device gate and input capacitor C iss The decision should be based on the conditions shown in equation (10): （10） in, f in The switching frequency of the IGBT device. This is the maximum voltage difference between the high and low levels of the switching transistor drive signal; IGBT gate driver chip drive current I gate-max The gate drive resistance of the IGBT device determines the condition that must be met, as shown in equation (11): （11） in, R int This refers to the gate drive resistor inside the IGBT device. R ext This refers to the external gate drive resistor of the IGBT device.

Images