CN106291310A - A kind of method of testing utilizing double-pulsed technology test IGBT dynamic switching characteristic and device - Google Patents

Abstract

The present invention relates to a kind of method of testing utilizing double-pulsed technology test IGBT dynamic switching characteristic and device；Utilizing single-chip microcomputer to send dipulse signal, first pulse makes to test IGBT and reaches rated operational current, and second pulse, for testing the dynamic characteristic of IGBT, utilizes dynamic electric voltage and current parameters that oscillograph and difference isolate IGBT when probe tests switch.Entering IGBT by dipulse signal drives plate realization control IGBT to cut-off within the extremely short time, avoids signal to interfere experimental circuit and test circuit isolation by isolating transformer；Utilization connects isolating transformer oscillograph and the electric current of main circuit and the voltage of IGBT both end voltage drive circuit outfan are measured, by oscillogram under oscillograph recording by difference isolation probe；According to rise and fall time, time delay, switch energy calculates IGBT dynamic switching characteristic parameter size.Reducing the parasitic parameter in circuit, test result is accurate.

Description

A test method for testing IGBT dynamic switching characteristics using double pulse technology and device

technical field

The invention relates to a method and device for quickly measuring the dynamic switching characteristic parameters of an insulated gate bipolar transistor (IGBT). Example) The drive terminal inputs a double pulse signal to realize the rapid turn-off and turn-on of the IGBT, and then uses a measurement system that eliminates power interference to measure the dynamic characteristics of the IGBT (rise and fall time, rise and fall delay time, switching energy). This test system is based on double-pulse technology, and the IGBT drive circuit is optimized. The single-chip microcomputer programming output signal and the IGBT drive board are used to isolate the output signal and boost the voltage to turn on and off the IGBT. For testing the main circuit, the DBC substrate is plated with copper to form a copper plate to form a loop for testing the main circuit. This system can test the dynamic switching characteristics of the IGBT with a withstand voltage of up to 3300V, which belongs to the innovative technology in the field of power testing.

Background technique

As a technology to test the dynamic characteristics of IGBT, double pulse test technology can clearly reflect the dynamic switching performance of IGBT in a short time. Its test method is simple, the waveform display is clear, and the calculation method of dynamic parameters is convenient. The double-pulse test technology uses the amplitude voltage (+15V/-8V) to turn on and off the IGBT, and the specific pulse time to test the dynamic performance of the switch during the rated operation of the IGBT. The tested IGBT is a half-bridge module in which two IGBTs are connected in series. The switch on the low potential side of the IGBT is controlled by a single-chip microcomputer with a double pulse signal, which is isolated and amplified by the IGBT drive board, and an inductor is connected in parallel to the high potential side of the IGBT. When the microcontroller applies a positive pulse between the gate and emitter of the low potential side IGBT (IGBT under test), the inductance connected in parallel to the switch on the high potential side of the IGBT module is gradually charged until the collector current reaches 100% of the test current . Then the IGBT is turned off quickly, the inductance is discharged through the freewheeling diode connected in parallel with the high potential side IGBT, and then the IGBT is quickly turned on again. In this process, the characteristics of IGBT turn-on and turn-off can be measured by rise time (tr), fall time (tf), turn-on loss (Eon), turn-off loss (Eoff), turn-on delay time (td on), Characterized by switching characteristics such as turn-off delay time (td off) and total energy loss (Etot). The withstand voltage value of the IGBT module tested by the traditional double pulse test system is small, but with the continuous development of the IGBT manufacturing process technology, the withstand voltage value of the IGBT is getting larger and larger, so we need to be able to test the IGBT with a high withstand voltage value The dynamic switch test system. In the traditional test system, the oscilloscope is greatly disturbed by the main circuit, which causes the test waveform to be distorted with the pulse, the experimental waveform is affected, and the error of the test result is very large, so we need an excellent isolation technology . The traditional test system cannot timely adjust the width of the double pulse waveform according to the test situation, and it is difficult to respond to the changes of different test devices and inductance parameters in the experiment in a timely manner. We need a double pulse width that can be adjusted at any time.

The present invention is based on the double-pulse test technology, uses a programmable single-chip microcomputer to send out a double-pulse signal that can be adjusted at any time during the test, and isolates the main circuit and the test circuit through electromagnetic shielding, isolation transformers and differential isolation probes, reducing the number of main circuits. Interference of high-voltage pulses on test waveforms. The main circuit is connected with a copper-plated DBC substrate to further reduce the parasitic parameters in the main circuit.

Contents of the invention

The invention mainly solves the problem of testing the dynamic switching characteristic parameters of the high withstand voltage and high power IGBT module. A linear regulated power supply with a maximum voltage of 2000V and four 1200V, 270uF film capacitors are used in parallel to provide the IGBT main circuit test power supply, the main circuit test power supply and an inductor of 0.21mH, a test module of MMG100SR120B, and a sampling resistor of 0.00967Ω Simple series connection forms the main circuit. The driving circuit is simply composed of MCU output signal, IGBT driver board, and dual-channel small power supply; the 5V port, 15V port, negative port and MCU output port of the dual-channel small power supply are connected to the left end of the IGBT driver board and the right end of the IGBT driver board It is connected to the G terminal and E terminal of the test module of MMG100SR120B. The oscilloscope circuit consists of a high-voltage differential isolation probe, which is connected to the two ends of G and E, C and E of the test module, and the two ends of the sampling resistor. In order to measure the characteristic parameters of IGBT dynamic switching, a test platform with simple operation, short test time, safety, reliability and good test accuracy is provided.

The method of the present invention is realized through the following technical solutions.

A test method and device for testing IGBT dynamic switching characteristics using double-pulse technology; a single-chip microcomputer is used to send a double-pulse signal, the first pulse makes the test IGBT reach the rated operating current, and the second pulse is used to test the dynamic characteristics of the IGBT, using an oscilloscope The dynamic voltage and current parameters of the IGBT when testing the switch with the differential isolation probe.

The double-pulse signal sent by the single-chip microcomputer enters the IGBT driver board to control the IGBT to be turned off in a very short time, and the experimental circuit and the test circuit are isolated through the isolation transformer to avoid mutual signal interference; use the oscilloscope connected to the isolation transformer and the differential isolation probe Measure the current of the main circuit and the voltage across the IGBT and the voltage at the output of the drive circuit, and record the waveform diagram with the oscilloscope; calculate the dynamic switching characteristic parameters of these IGBTs according to the rise and fall time, delay time, and switching energy.

The dynamic switching characteristics test steps of the IGBT of the present invention are as follows:

(1) Determine the capacitor for circuit wiring, and there is no pressure difference between the ports of the IGBT module;

(2) Plug in the triangular plug of the high-voltage DC power supply to ensure that the ground wire of the power supply is grounded and the ground wire of the oscilloscope is grounded;

(3) Short-circuit the GEs of the IGBT trigger segments not to be tested;

(4) Adjust the oscilloscope to the signal acquisition state, turn on the dual-channel power supply to supply 5V and 15V DC power to the IGBT driver board, let the single-chip microcomputer trigger a 5V pulse signal, and observe whether the double pulse waveform can be collected in the oscilloscope measurement channel CH1;

(5) Turn on the high-voltage power supply, raise the voltage to 600V, and see the change of the bus voltage from the channel CH2;

(6) Adjust the oscilloscope to the acquisition state again, open the three channels CH1, CH2, and CH3; use a single-chip microcomputer to trigger a double pulse signal;

(7) record the waveform of the oscilloscope;

(8) Slowly lower the voltage of the high-voltage power supply to 0V, turn off the high-voltage power supply and turn off the dual-channel power supply;

(9) Check the capacitor bank, there is no pressure difference between the ports of the IGBT module.

When testing 1200V IGBT, the test voltage is 600V.

The width of the first pulse sent by the microcontroller is preferably 36us, and the width of the second pulse is preferably 10us.

In order to realize the above method, an IGBT double-pulse test device was invented. The device can realize the test of the dynamic performance of the high-power IGBT. The device consists of a linear high-voltage DC power supply and a high-voltage capacitor busbar as the input terminal of the test circuit, two DC power supplies of 5V and 12V, and a 5V pulse signal output by a single-chip microcomputer as the input terminal of the drive circuit. The two IGBTs are connected through a half-bridge circuit, and an inductor is connected in parallel with the high-side IGBT for current control. The measurement terminal is measured by a differential isolation test lead connected to an oscilloscope.

Advantages of the present invention:

(1) The present invention creatively utilizes the copper-plated DBC substrate as the circuit wiring board of the dual-pulse test main circuit, effectively reduces the parasitic parameters in the test circuit, and improves the test accuracy and safety.

(2) The present invention uses a programmable single-chip microcomputer as a signal generation source, and the program designed can adjust the pulse width according to the situation at any time in the experiment, and the division value is 1us. This design can well adjust the different conditions of the experiment, so that the tested IGBT works at the rated current, and the tested IGBT dynamic switching characteristic parameters will be more accurate.

(3) The present invention adopts the BG2C-IGBT universal drive board to isolate the drive circuit and the main circuit, and isolates the main circuit and the oscilloscope circuit in a dual manner of an isolation transformer and a high-voltage differential isolation probe. It makes the test waveform disturb, the oscillation is small, and the test result is more accurate.

Description of drawings

Figure 1 is the circuit diagram of the experimental device built in this case.

Figure 2 is a system diagram of the experimental device built in this method case.

Figure 3 is a schematic diagram of the connection of the components of the experimental device built in this method case.

Fig. 4 is the circuit diagram of the copper-plated DBC substrate used in the case of this method.

Figure 5 is a waveform diagram of the voltage and current parameters tested in this experiment.

Figure 6a is a waveform diagram of voltage U _GE and current I _C when the IGBT is turned on after amplification.

Fig. 6b is a waveform diagram of voltage U _GE and current I _C when the enlarged IGBT is turned off.

Figure 7a is a waveform diagram of voltage U _CE and current I _C when the IGBT is turned on after amplification.

Fig. 7b is a waveform diagram of voltage U _CE and current I _C when the enlarged IGBT is turned off.

Figure 8a is a diagram of the switching energy when the IGBT is turned on.

Fig. 8b is a diagram of switching energy when the IGBT is turned off.

detailed description

The invention provides a device for testing the dynamic switching characteristics of an IGBT based on double-pulse technology. The whole set includes a TN-XXZ02 precision linear regulated power supply with a maximum value of 2000V, four 270uF, withstand voltage value 1200V, film capacitors produced by CORNELL DUBILIER company model 947C271K122CCMS, a copper-plated DBC substrate, A 0.21mH inductor, an IGBT test module MMG100SR120B, a 0.00967Ω sampling resistor, a BG2C-IGBT general driver board, a dual-channel power supply (+5V, +15V), a Tektronix oscilloscope, two Tektronix high-voltage differential isolation probes , a common probe wire and a large plexiglass box.

Taking the IGBT module MMG100SR120B as the test module, the parameter measurement of the dynamic switching characteristics of the IGBT module is realized by using the double pulse technology and the test device given above. The sampling resistor involved was provided by Professor Lu Guoquan of Virginia Tech, and the copper-plated DBC substrate was designed and processed by the Electronic Packaging Laboratory of the School of Materials, Tianjin University. The specific description of the IGBT dynamic switching characteristic testing device is as follows:

1. The double-pulse technology and IGBT dynamic switching characteristic testing device

(1) The IGBT dynamic switching characteristic test device adopts double pulse technology, and the experimental circuit diagram of the IGBT dynamic switching characteristic test is shown in Figure 1. When the microcontroller sends out the first pulse signal through the IGBT driver board, the test IGBT is turned on, and the voltage on the IGBT drops instantly. Due to the effect of the main circuit inductance, the main circuit current continues to rise. After the first pulse ends, the IGBT is turned off, the voltage on the IGBT increases to the power supply voltage instantaneously, and the current is discharged through the freewheeling diode and remains almost unchanged. At this time, the main circuit current has reached the rated current required for the test. The second pulse starts, the IGBT is turned on, the voltage on the IGBT drops again, and the current of the main circuit rises again. At this time, the dynamic characteristic parameters when the IGBT is turned on can be obtained by observing and recording the instantaneous voltage change waveform and current instantaneous change waveform on the IGBT. At the end of the second pulse, the IGBT is turned off again, the voltage instantly rises to the power supply voltage, and the main circuit current quickly drops to 0.

(2) The system diagram of the IGBT dynamic switching characteristic test, as shown in Figure 2, is divided into the main circuit and the driving circuit. The drive circuit is mainly composed of a single chip microcomputer, a dual drive channel DC power supply and an IGBT drive board to generate the pulse voltage required for switching the IGBT. The main circuit diagram is the half bridge circuit of the standard IGBT double pulse test circuit diagram. By shorting the IGBT at one end to test the dynamic characteristic parameters when the IGBT at the other end is switched.

2. The specific steps of the IGBT dynamic switching characteristic test are as follows:

(1) Check whether the circuit wiring is correct, check the capacitor with a multimeter DC voltage, whether there is residual voltage between the ports of the IGBT module (the instrument may be static after being placed in the plexiglass for a long time), if there is a voltage difference, Be sure to release it with the wire.

(2) Plug in the triangular plug of the high-voltage DC power supply to ensure that the ground wire of the power supply is grounded and the ground wire of the oscilloscope is grounded.

(3) Short-circuit the GEs of the IGBT trigger segments not to be tested.

(4) Adjust the oscilloscope to the state of collecting signals, turn on the dual-channel power supply to supply the 5V and 15V DC power of the IGBT driver board, let the single-chip microcomputer trigger a 5V pulse signal, and observe whether the double pulse waveform can be collected in the oscilloscope measurement channel CH1.

(5) Turn on the high-voltage power supply and slowly increase the voltage to 600V (at this time, you can see the change of the bus voltage from the channel CH2).

(6) Adjust the oscilloscope to the acquisition state again, and open the three channels CH1, CH2, and CH3. Use a single-chip microcomputer to trigger a double pulse signal.

(7) Observe and analyze the waveform of the oscilloscope.

(8) Slowly lower the voltage of the high-voltage power supply to 0V, wait for a period of time, turn off the high-voltage power supply and turn off the dual-channel power supply.

(9) Check the capacitor bank to see if there is any residual voltage in the IGBT module. If necessary, clean it with wires.

The main circuit test is preferably 600V (testing 1200V IGBT). The width of the first pulse sent by the microcontroller is preferably 36us, and the width of the second pulse is preferably 10us.

Before the experiment, it is necessary to conduct an electrostatic inspection on the experimental equipment, and wear an anti-static wristband during operation. The pulse strength generated by the experiment is relatively high, and the influence of EMC cannot be ignored. Therefore, wrap metal tape on the main circuit inductor and the microcontroller for electromagnetic shielding. The metal casing connection wires for electromagnetic shielding must be in full contact and grounded. The gap between the copper-plated DBC substrate lines is 5 mm, as shown in Figure 4, and a sufficiently large gap is reserved to avoid sparks.

Experimental test When the main circuit voltage is 600V, which is half of the maximum withstand voltage value of the IGBT module, the output voltage U _GE of the driving circuit when the IGBT is switched is measured using an oscilloscope, the voltage U _CE at both ends of the IGBT and the collector current I _C , such as Figure 5 shows. By amplifying the waveforms at the moment of turning on and off of the second pulse, as shown in Figure 6, Figure 7, and Figure 8, the dynamic changes of the parameters when the IGBT is switched can be clearly observed, combined with the definition of these parameters, it can be calculated more accurately Output the rise and fall time of the IGBT module, rise and fall delay time, switching energy and other parameters.

The IGBT dynamic switching characteristic testing device built with double pulse technology disclosed by the present invention can simply obtain the waveforms of the IGBT output voltage U _GE , the voltage U _CE at both ends of the IGBT and the collector current I _C varying with time. Comparing the experimental waveforms and parameters with the corresponding parameters on the IGBT datasheet, the error is small, and the experimental waveforms are basically consistent with the theoretical waveforms. The changes in the voltage parameters U _GE , U _CE and the current parameter I _C are also consistent with the theoretical calculations. The situation is close. The interesting IGBT dynamic characteristic parameters td on, td off, tr, tf are also consistent with the datasheet, reflecting the characteristic that the total fall time is greater than the total rise time. The experimentally measured switching energies Eon and Eoff are also in the same range as those on the datasheet. The connection points of the experimental circuit were relatively stable during the experiment, and there were no abnormalities such as sparks, fusing, and short circuits under high voltage and high current. And the experiment was repeated many times, and the measured parameters were all within a certain range. The test device of the invention has safety and operability, can realize the experimental measurement of the dynamic characteristics of the IGBT, and the experiment is rapid and the process is simple.

Claims (6)

1. the method for testing utilizing double-pulsed technology test IGBT dynamic switching characteristic；It is characterized in that utilizing single-chip microcomputer to send Dipulse signal, first pulse makes to test IGBT and reaches rated operational current, and second pulse is for testing the dynamic of IGBT Step response, utilizes oscillograph and difference isolation probe to test dynamic electric voltage and the current parameters of IGBT when switching.

2. the method for claim 1, is characterized in that the dipulse signal sent by single-chip microcomputer was entered IGBT and drives plate And then realization controls IGBT and cut-offs within the extremely short time, by isolating transformer, experimental circuit and test circuit isolation are avoided Signal interferes；Utilize and connect the oscillograph of isolating transformer and difference isolation probe to the electric current of main circuit and IGBT two ends electricity The voltage pressing drive circuit outfan measures, by oscillogram under oscillograph recording；According to rise and fall time, postpone Time, switch energy calculates the size of these IGBT dynamic switching characteristic parameters.

3. method as claimed in claim 2, is characterized in that the dynamic switching characteristic testing procedure of IGBT is as follows:

(1) determine the capacitor of circuit connection, between each port of IGBT module, there is no pressure reduction；

(2) being plugged by high-voltage DC power supply triangle plug, it is ensured that power ground ground connection, oscillograph is ground wire grounded；

(3) IGBT not tested is triggered short circuit between the GE of section；

(4) it is adjusted to oscillograph gather signal condition, opens dual channel source supply IGBT and drive the direct current of plate 5V and 15V Electricity, allows single-chip microcomputer trigger a 5V pulse signal, and whether observe dipulse waveform can be collected in oscilloscope measurement channel C H1 Arrive；

(5) open high voltage power supply, bring the voltage up to 600V, from channel C H2, see the situation of change of busbar voltage；

(6) oscillograph being adjusted to acquisition state again, by three channel C H1, CH2, CH3 open；Use single-chip microcomputer triggers Dipulse signal；

(7) the oscillographic waveform of record analysis；

(8) high-voltage power voltage is slowly dropped to 0V, close high voltage power supply and close dual channel source；

(9) inspection capacitance group, does not has pressure reduction between each port of IGBT module.

4. method as claimed in claim 3, when it is characterized in that the IGBT testing 1200V, test voltage is 600V.

5. method as claimed in claim 3, is characterized in that first pulse width that single-chip microcomputer sends is 36us, second arteries and veins Rushing width is 10us.

6. realize the test device utilizing double-pulsed technology test IGBT dynamic switching characteristic of claim 1, it is characterized in that dress Put by linear low density DC source and high voltage bearing capacitor bus-bar as test circuit input end, two unidirectional currents of 5V and 12V The 5V pulse signal of source and single-chip microcomputer output is as the input of drive circuit；Two IGBT are connected by half-bridge circuit, electricity Feel in parallel with high-pressure side IGBT to be used for controlling electric current；Measurement end is connect oscillograph by difference isolation test pencil and measures.