High-voltage capacitance thermal state test system for pulse power chip type multilayer ceramic capacitor

Abstract

The invention discloses a high-voltage capacitance thermal state test system for a pulse power chip multilayer ceramic capacitor, and the system comprises a space charge measurement module, an upper electrode and a lower electrode of the space charge measurement module are connected with two lead ends of a to-be-tested capacitor after pressing the to-be-tested capacitor together; an upper electrode of the space charge measurement module is connected to one end of the high-voltage capacitance standard board through the first high-voltage relay and the primary of the pulse transformer in sequence, and a lower electrode and the other end of the high-voltage capacitance standard board are grounded; the secondary of the pulse transformer is connected with a voltmeter and an alternating current power supply circuit in parallel; the direct-current high-voltage power supply circuit, the high-voltage pulse power supply circuit and the discharging circuit are connected to the space charge measuring module in parallel. The capacitance value can be subjected to thermal state testing under the high-voltage pressurization condition of the to-be-tested capacitor, the method can be used for magnitude transmission of the capacitance value of the pulse capacitor, high accuracy and traceability of a measurement result are ensured, and a testing means and method can be provided for design of an energy storage system of a pulse power device.

Description

Technical Field

[0001] The present invention belongs to the field of pulse power device state evaluation, and in particular relates to a high-voltage capacitance thermal state testing system for a pulse power chip multilayer ceramic capacitor. Background Art

[0002] Pulse power technology has greatly promoted the development of effect simulation, physical diagnosis, material behavior and special new research fields. In the past decade, pulse systems such as exploding foil initiation systems, pulse lasers, and pulse generators have achieved leapfrog development. The biggest problem at present is the lack of high-accuracy metrology-grade high-amplitude pulse current sources, which cannot solve the traceability problem of high-current pulse parameters. Metrology-grade pulse sources not only focus on the accuracy of output electrical parameters, but also on their output repeatability and working stability. Pulse power chip multilayer ceramic capacitors (hereinafter referred to as pulse capacitors) are widely used in pulse energy storage systems due to their high power density, good capacitance-to-volume ratio, and large instantaneous discharge energy. Their capacitance value is a key indicator used directly in pulse source design.

[0003] Pulse capacitors store energy through DC high-voltage polarization and rapidly discharge at speeds of several kA / microseconds. Their service conditions are characterized by high voltage, high current, and uneven temperature distribution. The inherent nonlinearity of pulse capacitor ceramic dielectrics results in significant pressure-temperature variations in their dielectric properties, leading to significant changes in capacitance under service conditions. Pulse capacitor capacitance testing must be performed in an actual high-voltage environment, and the measurement method should minimize the introduction of significant measurement uncertainty. Current capacitance measurements require low excitation voltages and frequencies (typical excitation: 1kHz, 1V), or require wide-range, high-dynamic-voltage standard capacitors. These methods are detached from actual operating conditions, difficult to manufacture, and expensive, making them less applicable and the confidence level in the measurement results low. Consequently, the resulting measurement results cannot reflect the actual capacitance of the pulse capacitor under thermal service conditions.

[0004] The direct result of the lack of thermal testing methods for the capacitance of pulse capacitors is that the pulse capacitors used in large quantities during the device development process generally have a relaxed allowable error range in parameter design, and need to be designed with a high margin of derating according to the requirements of the electronic equipment reliability prediction manual. As a result, the pulse current curve output by the existing high-amplitude pulse current source has extremely poor repeatability. In addition, this mode of using pulse capacitors in multiples causes great economic waste, and it is difficult to miniaturize and optimize it in the future. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-voltage capacitance thermal state testing system for pulse power chip multilayer ceramic capacitors.

[0006] The technical solutions for achieving the purpose of the present invention are as follows:

[0007] A high-voltage capacitance hot-state test system for pulse power chip multilayer ceramic capacitors includes a space charge measurement module, whose upper and lower electrodes jointly press the capacitor and are respectively connected to the two lead ends of the capacitor; the upper electrode of the space charge measurement module is connected to one end of a high-voltage capacitance standard plate through a first high-voltage relay and the primary of a pulse transformer in sequence, and the lower electrode of the space charge measurement module and the other end of the high-voltage capacitance standard plate are both grounded; the secondary of the pulse transformer is connected in parallel with a voltmeter and an AC current power supply circuit, and the AC current power supply circuit includes a matching resistor, a lead inductor, an AC current power supply and an ammeter connected in series in sequence; it also includes a DC high-voltage power supply circuit, a high-voltage pulse power supply circuit and a discharge circuit connected in parallel to the space charge measurement module; the DC high-voltage power supply circuit is composed of a second high-voltage relay, a protective resistor and a DC high-voltage power supply connected in series in sequence, the high-voltage pulse power supply circuit is composed of a third high-voltage relay, a coupling capacitor and a high-voltage pulse power supply connected in series in sequence, the discharge circuit is composed of a fourth high-voltage relay in series with a high-voltage power resistor, and the discharge circuit is also provided with a current sensor.

[0008] Preferably, the space charge measurement module includes a shielding box, wherein a protrusion is provided on the outer side of the upper wall of the shielding box to form a lower electrode. A piezoelectric film is provided on the inner side of the upper wall of the shielding box, corresponding to the plane of the lower electrode. A shielding layer is provided below the piezoelectric film, and the piezoelectric film is also connected to an amplifier. The upper electrode is connected to the upper portion of the shielding box via an insulating compression structure; the compression structure is used to compress the capacitor with the lower surface of the upper electrode and the upper surface of the lower electrode. Furthermore, a high-sensitivity resonant acoustic emission sensor is also provided within the shielding box.

[0009] Preferably, a temperature control unit is further included to control the ambient temperature of the high-voltage capacitance standard plate.

[0010] The testing method of the above-mentioned testing system includes:

[0011] Step 1: Select a pulse power multilayer ceramic capacitor with a capacitance close to that of the pulse power multilayer ceramic capacitor to be tested, denoted as C1.

[0012] Step 2, determining the output parameters of the AC current power supply;

[0013] 2.1 Leave the high-voltage capacitance standard board empty and connect C1 to the space charge measurement module;

[0014] 2.2 Disconnect the first and fourth high-voltage relays, and connect the second and third high-voltage relays; 2.3 Use the electroacoustic pulse method to test the space charge distribution curve Q of C1 when the DC high-voltage power supply is pressurized at the rated voltage for t time; 2.4 Connect the first high-voltage relay, adjust the output parameters of the AC current power supply, and use the electroacoustic pulse method to test the space charge distribution curve Q of C1 when the AC current power supply output parameters are adjusted for the i-th time. i, i=1,2,…n; the AC current power supply output parameters include current amplitude and frequency;

[0015] 2.5 From Q1, Q2, ..., Q n Find the space charge distribution curve with the smallest absolute difference from the Q curve.

[0016] Let the corresponding AC current power supply output parameter be P;

[0017] Step 3: calibrate the test system circuit parameters;

[0018] 1.3.1 Connect one adjustable standard capacitor as a high-voltage capacitance standard to the system, and another adjustable standard capacitor to the space charge measurement module;

[0019] 1.3.2 Connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays;

[0020] 1.3.3 Adjust the AC current power supply output parameter to P and simultaneously adjust the capacitance values ​​of the two adjustable standard capacitors. Based on the adjusted capacitance values ​​and the voltage value V measured by the voltmeter, obtain the voltage-capacitance response curve of the test system, i.e., the CV curve.

[0021] Step 4, testing the high voltage capacitance of the pulse power chip multilayer ceramic capacitor under test;

[0022] 4.1 Connect C1 as a high-voltage capacitance standard board to the system, and connect the pulse power chip multilayer ceramic capacitor to be measured to the space charge measurement module; connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays; adjust the AC current power supply output parameter to P, and obtain the total system capacitance value Z1 based on the voltage value V and CV curve measured by the voltmeter;

[0023] 4.2 Connect C1 as a high-voltage capacitance standard board to the system, leaving the space charge measurement module vacant. Connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays. Adjust the AC current power supply output parameter to P, and obtain the total system capacitance Z2 based on the voltage value V and CV curve measured by the voltmeter.

[0024] 4.3 The total system capacitance value Z1 minus the total system capacitance value Z2 can be used to obtain the high-voltage capacitance value of the pulse power chip multilayer ceramic capacitor under test.

[0025] The present invention can perform thermal capacitance testing on pulse power chip multilayer ceramic capacitors under high-voltage pressurization conditions, can be used for the measurement value transfer of pulse capacitor capacitance, ensures high accuracy and traceability of measurement results, and can provide testing means and methods for the design of energy storage systems for pulse power devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of a pulse power chip multilayer ceramic capacitor.

[0028] Figure 3 This is a schematic diagram of the structure of the space charge measurement module in the invention. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the high-voltage capacitance thermal test system of the pulse power chip multilayer ceramic capacitor is mainly composed of a first pulse power chip multilayer ceramic capacitor 1, a space charge measurement module 2, a lead inductor 3, an AC current power supply module 4, a matching resistor 5, an ammeter module 6, a second pulse power chip multilayer ceramic capacitor 7, a reference module 8, a voltmeter module 9, a pulse transformer 10, a first high-voltage relay 11a, a second high-voltage relay 11b, a third high-voltage relay 11c, a fourth high-voltage relay 11d, a protective resistor 12, a DC high-voltage power supply module 13, a coupling capacitor 14, a high-voltage pulse power supply module 15, a high-voltage power resistor 16, and a current sensor 17.

[0031] An industrial control module is also provided. The space charge measurement module 2, AC current power module 4, ammeter module 6, reference module 8, voltmeter module 9, first high-voltage relay 11a, second high-voltage relay 11b, third high-voltage relay 11c, fourth high-voltage relay 11d, DC high-voltage power module 13, high-voltage pulse power module 15, and current sensor 17 are all communicatively connected to and controlled by the industrial control module. The communication connection preferably uses a LAN port communication protocol.

[0032] The structure of pulse power chip multilayer ceramic capacitor is as follows Figure 2 As shown, the space charge measurement module 2 can adopt the structure of the electroacoustic pulse method test system given in the "Electroacoustic Pulse Test Method for Space Charge Distribution in Solid Insulating Materials (Machinery Industry Standard of the People's Republic of China JB / T12927-2016)".

[0033] In order to better adapt to the pulse power chip multilayer ceramic capacitor, the present invention makes improvements on this basis.

[0034] like Figure 3 As shown, in the present invention, the space charge measurement module 2 is mainly composed of a lower electrode 201 , a high-sensitivity resonant acoustic emission sensor 202 , a piezoelectric film 203 , a shielding layer 204 , an amplifier 205 , and an upper electrode 206 .

[0035] The first pulse power chip multilayer ceramic capacitor 1 is placed in the middle of the upper and lower electrodes of the space charge measurement module 2 and is pressed. The surface of the upper electrode 206 (high voltage pole) and the lower electrode 201 (low voltage pole) of the space charge measurement module 2 are rectangular, and the long side of the rectangle is parallel to the lead ends at both ends of the first pulse power chip multilayer ceramic capacitor 1. After pressing, the contact area is 1 / 3 of the upper and lower surfaces of the first pulse power chip multilayer ceramic capacitor 1. The lead ends at both ends of the first pulse power chip multilayer ceramic capacitor 1 are welded to the upper electrode 206 at the left end and to the lower electrode 201 at the right end; all surfaces of the first pulse power chip multilayer ceramic capacitor 1 outside the pressed parts of the upper electrode 206 and the lower electrode 201 are coated with high-voltage insulating silicone grease.

[0036] Among them, the high-sensitivity resonant acoustic emission sensor 202 is used to cut off the power of the DC high-voltage power supply module 13 and the high-voltage pulse power supply module 15 through the industrial control module during the test process, if the collected signal undergoes a transient jump.

[0037] Reference module 8 includes a second pulse power multilayer ceramic capacitor 7 and a temperature control unit. The second pulse power multilayer ceramic capacitor 7 is placed within the temperature control unit, which controls its ambient temperature within an adjustable range. Typically, the temperature is controlled between 15°C and 35°C, with a temperature fluctuation of less than 0.1°C.

[0038] The on and off of the first high-voltage relay 11a, the second high-voltage relay 11b, the third high-voltage relay 11c, and the fourth high-voltage relay 11d are controlled by the industrial control module; the piezoelectric signal generated by the piezoelectric film 203 of the space charge measurement module 2 is amplified by the amplifier 205 and then collected, measured, and stored by the industrial control module, and the signal collected by the high-sensitivity resonant acoustic emission sensor 202 is also collected, measured, and stored by the industrial control module.

[0039] The measurement signals of the ammeter module 6 and the voltmeter module 9 are collected, measured and stored by the industrial control module. The ammeter module 6 is collected by a squirrel cage structure standard resistor AC shunt. The AC and DC current difference of the squirrel cage structure standard resistor AC shunt is less than 5×10 -6 .

[0040] Fourth high-voltage relay 11d and power resistor 16 form a discharge circuit. The sum of power resistor 16, the on-resistance of fourth high-voltage relay 11d, and the discharge circuit resistance should meet the underdamping condition. The first pulse power multilayer ceramic capacitor 1 is discharged by disconnecting first, second, and third high-voltage relays 11a, 11b, and 11c, and connecting fourth high-voltage relay 11d.

[0041] The output voltage of the DC high-voltage power supply module 13 should be no less than 1.5 times the rated voltage of the first pulse power chip multilayer ceramic capacitor 1.

[0042] The high-voltage pulse power supply module 15 has a rated voltage of not less than 2000V and a pulse width of not more than 5ns.

[0043] The AC current power supply module 4 has an adjustable frequency within the range of 10 Hz to 100 kHz, and its inductive load capacity meets the requirements of the pulse transformer 10 .

[0044] Using the aforementioned pulse power chip multilayer ceramic capacitor high-voltage capacitance thermal test system, the method for performing a high-voltage capacitance thermal test on the pulse power chip multilayer ceramic capacitor under test is as follows:

[0045] S1. Select a pulse power multilayer ceramic capacitor with a capacitance (nominal value) close to that of the pulse power multilayer ceramic capacitor being tested, and record it as C1.

[0046] The temperature control unit of the reference module 8 controls the ambient temperature of the second pulse power chip multilayer ceramic capacitor 7 to be at a standard temperature, preferably 20°C.

[0047] S2. Determine the output parameters of the AC current power module

[0048] First, the second pulse power chip multilayer ceramic capacitor 7 is left vacant (ie, the second pulse power chip multilayer ceramic capacitor 7 is not connected in the system), and C1 is connected to the space charge measurement module as the first pulse power chip multilayer ceramic capacitor 1.

[0049] The first high-voltage relay 11a and the fourth high-voltage relay 11d are disconnected, and the second high-voltage relay 11b and the third high-voltage relay 11c are connected. The space charge distribution curve Q of C1 is tested by the electroacoustic pulse method when the DC high-voltage power supply module 13 is pressurized at the rated voltage for 30 minutes.

[0050] Afterwards, the first high-voltage relay 11a is connected, and the industrial control module adjusts the AC current output signal of the AC current power supply module 4, including the current amplitude and frequency. Simultaneously, the measurement signals of the ammeter module 6 and the voltmeter module 9 are obtained through testing. Using the electroacoustic pulse method, the space charge distribution curve of capacitor C1 is obtained under the superposition of different current magnitudes and frequencies. Using the principle of minimizing the area of ​​the absolute value of the curve difference, the output current amplitude and frequency of the AC current power supply module 4 that match C1 are obtained (i.e., the output parameter of the AC current power supply module 4 is P), and then capacitor C1 is discharged.

[0051] During the test, if the signal collected by the high-sensitivity resonant acoustic emission sensor 202 changes instantaneously, the DC high-voltage power supply module 13 and the high-voltage pulse power supply module 15 are powered off for protection.

[0052] S3. Calibrate test system circuit parameters

[0053] Two adjustable standard capacitors are used, one of which is connected to the system as the second pulse power chip multilayer ceramic capacitor 7, and the other is connected to the space charge measurement module as the first pulse power chip multilayer ceramic capacitor 1.

[0054] The first high-voltage relay 11 a and the second high-voltage relay 11 b are turned on, and the third high-voltage relay 11 c and the fourth high-voltage relay 11 d are turned off.

[0055] Set the output parameter of AC current power supply module 4 to P, and synchronously adjust the capacitance of the two adjustable standard capacitors from the lower limit of C1 to the nominal value. Measure the voltage V of voltmeter module 9 at different capacitance values ​​of the adjustable standard capacitors to obtain the voltage-capacitance response curve of the test system, i.e., the CV curve.

[0056] S4. Obtain the thermal test results of the capacitance value of the tested sample

[0057] Connect C1 to the system as the second pulse power multilayer ceramic capacitor 7, and connect the measured pulse power multilayer ceramic capacitor to the space charge measurement module as the first pulse power multilayer ceramic capacitor 1. Connect the first high-voltage relay 11a and the second high-voltage relay 11b, and disconnect the third high-voltage relay 11c and the fourth high-voltage relay 11d. The DC high-voltage power supply module 13 applies the rated voltage to C1, sets the output parameter of the AC current power supply module 4 to P, obtains the voltage value V from the voltmeter module 9, and then calculates the total capacitance value Z1 of the test system based on the CV curve.

[0058] Connect C1 to the system as the second pulse power chip multilayer ceramic capacitor 7, leaving the space charge measurement module vacant (i.e., the space charge measurement module is not connected to the first pulse power chip multilayer ceramic capacitor 1). Connect the first high-voltage relay 11a and the second high-voltage relay 11b, and disconnect the third high-voltage relay 11c and the fourth high-voltage relay 11d. Apply the rated voltage to C1 with the DC high-voltage power supply module 13, set the output parameter of the AC current power supply module 4 to P, obtain the voltage value V from the voltmeter module 9, and then calculate the total capacitance value Z2 of the test system based on the CV curve.

[0059] The total system capacitance value Z1 is subtracted from the total system capacitance value Z2 to obtain the high-voltage capacitance value of the pulse power chip multilayer ceramic capacitor under test, that is, the thermal test result of the capacitance value of the pulse power chip multilayer ceramic capacitor under test.

[0060] S5. Verify the effectiveness of the test method

[0061] The hot capacitance of the pulse power chip multilayer ceramic capacitor under test was measured under specified voltage conditions and then discharged. The discharge current measured by current sensor 17 was transmitted to the industrial control module for storage. The test was repeated 10 times. The experimental standard deviation of the pulse current peak value and oscillation period was calculated using the Bessel method. The experimental standard deviations were both less than 0.01, indicating that the method was effective.

Claims

1. Pulse power chip multilayer ceramic capacitor high voltage capacitance thermal test system, characterized by: It includes a space charge measurement module, whose upper electrode and lower electrode jointly press the capacitor and are respectively connected to the two lead ends of the capacitor; the upper electrode of the space charge measurement module is connected to one end of a high-voltage capacitance standard plate through a first high-voltage relay and the primary of a pulse transformer in sequence, and the lower electrode of the space charge measurement module and the other end of the high-voltage capacitance standard plate are both grounded; the secondary of the pulse transformer is connected in parallel with a voltmeter and an AC current power supply circuit, and the AC current power supply circuit includes a matching resistor, a lead inductor, an AC current power supply and an ammeter connected in series in sequence; it also includes a DC high-voltage power supply circuit, a high-voltage pulse power supply circuit and a discharge circuit connected in parallel to the space charge measurement module; the DC high-voltage power supply circuit is composed of a second high-voltage relay, a protective resistor and a DC high-voltage power supply connected in series in sequence, the high-voltage pulse power supply circuit is composed of a third high-voltage relay, a coupling capacitor and a high-voltage pulse power supply connected in series in sequence, the discharge circuit is composed of a fourth high-voltage relay in series with a high-voltage power resistor, and the discharge circuit is also provided with a current sensor.

2. The test system according to claim 1, wherein: The space charge measurement module includes a shielding box, a protrusion is provided on the outer side of the upper wall of the shielding box to form a lower electrode, a piezoelectric film is provided on the inner side of the upper wall of the shielding box, corresponding to the plane of the lower electrode, a shielding layer is provided under the piezoelectric film, and the piezoelectric film is also connected to the amplifier; the upper electrode is connected to the upper part of the shielding box through an insulating compression structure; The pressing structure is used for the lower surface of the upper electrode and the upper surface of the lower electrode to jointly press the capacitor.

3. The test system according to claim 2, wherein: A high-sensitivity resonant acoustic emission sensor is also arranged in the shielding box.

4. The test system according to claim 1, wherein: It also includes a temperature control unit for controlling the ambient temperature of the high-voltage capacitance standard plate.

5. The testing method of the testing system according to claim 1, wherein: include: Step 1: Select a pulse power multilayer ceramic capacitor with a capacitance close to that of the pulse power multilayer ceramic capacitor to be tested, denoted as C1. Step 2, determining the output parameters of the AC current power supply; 2.1 Leave the high-voltage capacitance standard board empty and connect C1 to the space charge measurement module; 2.2 Disconnect the first high-voltage relay and the fourth high-voltage relay, and connect the second high-voltage relay and the third high-voltage relay; 2.3 Using the electroacoustic pulse method, test the space charge distribution curve Q of C1 when a DC high voltage power supply is applied at rated voltage for time t; 2.4 Turn on the first high-voltage relay, adjust the AC current power supply output parameters, and use the electroacoustic pulse method to test the space charge distribution curve Q of C1 under the i-th adjustment of the AC current power supply output parameters. i , i=1,2,…n; the AC current power supply output parameters include current amplitude and frequency; 2.5 From Q1, Q2, ..., Q n In the equation, find the space charge distribution curve with the smallest area difference from the Q curve, and let the corresponding AC current power supply output parameter be P; Step 3: calibrate the test system circuit parameters; 1.3.1 Connect one adjustable standard capacitor as a high-voltage capacitance standard to the system, and another adjustable standard capacitor to the space charge measurement module; 1.3.2 Connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays; 1.3.3 Adjust the AC current power supply output parameter to P and simultaneously adjust the capacitance values ​​of the two adjustable standard capacitors. Based on the adjusted capacitance values ​​and the voltage value V measured by the voltmeter, obtain the voltage-capacitance response curve of the test system, i.e., the CV curve. Step 4, testing the high voltage capacitance of the pulse power chip multilayer ceramic capacitor under test; 4.1 Connect C1 as a high-voltage capacitance standard board to the system, and connect the pulse power chip multilayer ceramic capacitor to be measured to the space charge measurement module; connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays; adjust the AC current power supply output parameter to P, and obtain the total system capacitance value Z1 based on the voltage value V and CV curve measured by the voltmeter; 4.2 Connect C1 as a high-voltage capacitance standard board to the system, leaving the space charge measurement module vacant. Connect the first and second high-voltage relays, and disconnect the third and fourth high-voltage relays. Adjust the AC current power supply output parameter to P, and obtain the total system capacitance Z2 based on the voltage value V and CV curve measured by the voltmeter. 4.3 The total system capacitance value Z1 minus the total system capacitance value Z2 can be used to obtain the high-voltage capacitance value of the pulse power chip multilayer ceramic capacitor under test.

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