CN102156253B - Double-pulse test method for IGBT module - Google Patents

Abstract

The invention belongs to the technical field of power semiconductor devices, and in particular relates to a double-pulse test method of an IGBT module. By adding positive driving voltage and negative voltage between the gate and emitter of the tested IGBT module, it can control its turn-on and turn-off, send two PWM pulses to the IGBT module, and block the two PWM pulses , make the IGBT module undergo the turn-on-off-turn-on-turn-off process to assess the ability of the module to withstand overcurrent and master its turn-on and turn-off characteristics, providing reference and basis for the application of high-voltage, high-current IGBT modules.

Description

A double-pulse test method for IGBT modules

technical field

The invention belongs to the technical field of power semiconductor devices, and in particular relates to a double-pulse test method for an IGBT module.

Background technique

Insulated gate bipolar transistor IGBT belongs to the technical field of power semiconductor devices. Power semiconductor devices are high-power semiconductor devices used for power conversion and power control. Its development has gone through stages such as diodes, thyristors, and power transistors.

Diode, also known as crystal diode, or diode for short, is an electronic component that only transmits current in one direction. It is a device with 2 terminals joined by 1 part number, and has the property of causing current to flow or not to flow according to the direction of the applied voltage. A crystal diode is a p-n junction formed by a p-type semiconductor and an n-type semiconductor, and a space charge layer is formed on both sides of the interface, and a self-built electric field is built. When there is no external voltage, the diffusion current caused by the carrier concentration difference on both sides of the p-n junction is equal to the drift current caused by the self-built electric field, and it is in a state of electrical balance.

Diodes are uncontrollable devices, and the most important characteristic is unidirectional conductivity. In the circuit, current can only flow in from the positive terminal of the diode and flow out from the negative terminal.

Thyristor (Thyristor) is the abbreviation of thyristor, also known as silicon-controlled rectifier, formerly referred to as thyristor; in 1957, General Electric Company of the United States developed the world's first thyristor product, and in 1958 it was Its commercialization; the thyristor is a PNPN four-layer semiconductor structure, which has three poles: anode, cathode and gate; the thyristor has the characteristics of a silicon rectifier device, can work under high voltage and high current conditions, and its working process can be controlled, It is widely used in electronic circuits such as controllable rectification, AC voltage regulation, non-contact electronic switch, inverter and frequency conversion.

The thyristor is a semi-controlled device. During the working process, its anode A and cathode K are connected to the power supply and load to form the main circuit of the thyristor. The gate G and cathode K of the thyristor are connected to the device for controlling the thyristor to form the control of the thyristor. circuit.

The working conditions of the thyristor are:

1) When the thyristor is subjected to the reverse anode voltage, no matter what voltage the gate is subjected to, the thyristor is in the off state;

2) When the thyristor is subjected to a positive anode voltage, the thyristor is turned on only when the gate is subjected to a forward voltage;

3) When the thyristor is turned on, as long as there is a certain positive anode voltage, the thyristor remains on regardless of the gate voltage, that is, after the thyristor is turned on, the gate loses its function;

4) When the thyristor is turned on, when the main circuit voltage (or current) decreases to close to zero, the thyristor is turned off.

Among the power transistors, IGBT is developing most rapidly. IGBT (Insulated Gate Bipolar Transistor), an insulated gate bipolar transistor, is a composite fully controlled type composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor). The voltage-driven power semiconductor device has the advantages of high input impedance of MOSFET and low conduction voltage drop of GTR. The saturation voltage of GTR is low, the carrying current density is large, but the driving current is large; the driving power of MOSFET is small, the switching speed is fast, but the conduction voltage drop is large, and the current carrying density is small. IGBT combines the advantages of the above two devices, the driving power is small and the saturation voltage is low, its frequency characteristics are between MOSFET and power transistor, and it can work normally in the frequency range of tens of kHz. Wider and wider applications, occupying a dominant position in high-frequency and medium-power applications.

The IGBT is a fully-controlled device. If a driving positive voltage is applied between the gate and the emitter of the IGBT, the MOSFET will be turned on, so that the collector and the base of the PNP transistor will be in a low resistance state to make the transistor turn on; If the voltage between the gate and the emitter of the IGBT is 0V or a negative voltage, the MOSFET is turned off, and the supply of the base current of the PNP transistor is cut off, so that the transistor is turned off. The IGBT is also a voltage-controlled device like the MOSFET. A driving voltage of more than ten V is applied between its gate and the emitter, and only a leakage current of the μA level flows, basically consuming no power.

IGBT has the characteristics of fast switching speed, low conduction voltage, low driving power, high operating frequency, and flexible control. Therefore, it has been more and more widely used in modern power electronics technology. At present, the high-voltage, high-current IGBT has been modularized, and its drive circuit has now produced an integrated IGBT-specific drive circuit, which has better performance, higher reliability, and smaller size, and will be used in high-power applications in the future. However, the high-voltage and large-capacity IGBT module still lacks simple and reliable dynamic characteristic testing methods. Some test instruments can only measure the static parameters of the IGBT module, and cannot obtain its dynamic characteristic parameters. Lack of guidance and reference.

At present, some testing instruments and testing methods can measure the static characteristics of IGBT modules and obtain relevant static working parameters, which can provide a certain basis for the selection and use of IGBT modules; for the dynamic characteristics of IGBT modules, there is still a lack of better testing methods .

The single-pulse test can fully observe the turn-off process of the IGBT. If you only need to pay attention to the turn-off process, you can use the single-pulse test; however, in most power electronic devices, the inductance of the load is relatively large. After the IGBT is turned off, the inductance Generally, the current will not be interrupted, and the diode will continue to flow. At this time, when the IGBT is turned on, there will be a reverse recovery process of the diode; and there is no reverse recovery process of the diode in the single-pulse test, so the double-pulse test is better than the single-pulse test. More realistic and more in line with actual working conditions.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned prior art, the present invention proposes a new test method-double-pulse test method. Compared with other test methods, this method has obvious advantages: the circuit is simple, the method is reliable, and it can test the IGBT module. Overcurrent capability and dynamic characteristics.

The IGBT module is a fully-controlled device. By adding a positive driving voltage and a negative voltage between the gate and the emitter of the IGBT, it can be controlled to turn it on or off. It only needs to send PWM to the IGBT module twice. Pulse, block two PWM pulses, make the IGBT module undergo the turn-on-off-turn-on-turn-off process, then you can assess the ability of the module to withstand the turn-off overcurrent and turn-off surge voltage, and master its turn-on and turn-off characteristics. The application of high voltage and high current IGBT modules provides reference and basis. As shown in Figure 1, the specific test methods are:

(1) Determine the test circuit;

Determine a suitable circuit structure to simulate the actual working state of the insulated gate bipolar transistor IGBT module; the circuit structure is a double-pulse test circuit composed of an IGBT module, and the double-pulse test circuit includes a power supply, a switch, a voltage regulator transformer, transformer, rectifier bridge, DC capacitor, busbar, radiator, reactor, H-bridge IGBT module; the DC capacitor acts as a voltage support, and the DC capacitor is connected to the H-bridge IGBT module through the busbar; the H-bridge IGBT The module is installed on the radiator; the power supply is connected to the rectifier bridge after passing through the switch, voltage regulator and transformer, and the DC capacitor is charged after the AC is converted into DC; the reactor is used as the inductive load of the H-bridge IGBT module and connected to the H-bridge The output terminal of the IGBT module; the H-bridge IGBT module includes a first IGBT (T1), a second IGBT (T2), a third IGBT (T3) and a fourth IGBT (T4), wherein the third IGBT (T3) is Measure IGBT;

(2) According to the test circuit and parameters, calculate the pulse width of the pulse width modulation PWM;

计算出被测IGBT达到目标值所需触发脉冲的宽度；After the test circuit is determined, according to the parameters of the components in the circuit, the formula

Calculate the width of the trigger pulse required for the tested IGBT to reach the target value;

(3) Perform correct wiring according to the test circuit;

Conduct wiring according to the test circuit, connect the power supply after confirming that the wiring is correct, so as to ensure the safety of the test;

(4) Block the pulse of the pulse width modulation PWM of the IGBT module;

Lock the controller and block the trigger pulses of all IGBTs in the H-bridge IGBT module;

(5) Charge the DC capacitor to the rated value;

Slowly adjust the voltage regulator to charge the DC capacitor through the rectifier bridge until the rated value of the DC capacitor is reached;

(6) Disconnect the charging circuit;

When the DC capacitor reaches the rated value, the capacitor voltage remains basically unchanged, and the charging circuit is disconnected;

(7) Create test conditions;

Send a continuous conduction signal to the second IGBT (T2), and the second IGBT (T2) is continuously turned on;

(8) sending a pulse width modulated PWM pulse to the third IGBT (T3) to be tested;

Unlock the controller, and send a PWM pulse to the third IGBT (T3) under test according to the pulse width time calculated by the method in step (2), so that it is in the on state;

(9) When the third IGBT (T3) under test reaches the rated current value, block the PWM pulse;

After the third IGBT (T3) under test is turned on, the DC capacitor, the second IGBT (T2), the load and the third IGBT (T3) form a loop, and the current on the load increases linearly until it reaches the third IGBT (T3) under test. The rated current peak value I _M blocks the PWM pulse, thereby turning off the third IGBT (T3) under test;

(10) Send PWM pulses to the third IGBT (T3) under test again after a period of time;

After the third IGBT (T3) under test is turned off, the current on the load will decrease slightly. After a period of time, calculate the pulse width time according to the method in step (2), and give the pulse width time to the third IGBT (T3) under test again. Send PWM pulse to make it open;

(11) When the third IGBT (T3) under test reaches the set off current value, block the PWM pulse;

After the third IGBT (T3) under test is turned on, the current on the load will continue to increase linearly on the basis of I _M until it reaches the peak value of the turn-off current set by the third IGBT (T3) under test, and the PWM will be blocked. pulse, the third IGBT (T3) under test is turned off again;

(12) If the third IGBT (T3) under test is intact during the whole process, the test circuit is powered off;

Under the condition of rated DC voltage or higher than the rated DC voltage, after the tested third IGBT (T3) has withstood the test process of on-off-on-off peak current, if the tested IGBT module is intact during the whole process, then The test circuit is powered off;

(13) The test is over.

The beneficial effects of the present invention are:

The test of high-power modules usually adopts full-power operation test, and the test circuit is relatively complicated. Under the condition that the thermal design is not considered, the double-pulse test method proposed by the present invention can be used to realize the assessment of the voltage, current and electrical stress of the IGBT module. In the test, the double pulse width can be adjusted. Under the condition of ensuring the safety of the device, the pulse width is gradually released from narrow to wide until the peak current for examination described in the present invention is reached.

The double-pulse test method of the IGBT module according to the present invention provides a brand-new testing method for the IGBT module, and has important significance for the commercial application of the module in the future. The test circuit of the method is simple, the test method is reliable, and the test risk is low. The main technical parameters and related dynamic turn-on and turn-off operating characteristics of the IGBT module switching process can be obtained, providing reference and basis for the application of high-voltage and high-current modules, and solving the application problems of high-voltage and high-current IGBT modules.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 shows the double pulse test circuit diagram according to the method of the present invention;

Fig. 2 shows the voltage, current and PWM pulse waveform figure according to the method of the present invention;

Figure 3 is a flow chart of the method according to the invention.

Detailed ways

Method of the present invention specifically comprises the following steps:

1) Carry out test circuit wiring according to the test circuit diagram;

2) After checking that the wiring is correct, the main circuit is switched on and powered on;

3) The T1 and T4 tubes are always in the blocked state, and the T2 tube is in the open state, blocking the PWM pulse of the tested IGBT (T3 tube);

4) Assuming that the capacitor is large, charge the DC capacitor to the rated value U _N , and the capacitor voltage will remain basically unchanged after charging;

5) Disconnect the rectifier charging circuit;

6) Send a PWM pulse to the tested IGBT module (T3 tube), and T3 is turned on, so the DC capacitor C, the reactor L and the upper right IGBT T2 form a loop, and the current on the reactor increases linearly until it reaches the peak value of the rated current of the device I _M , observe its conduction waveform through an oscilloscope;

7) If there is no abnormality in the IGBT module, block the PWM pulse of the IGBT under test, T3 is turned off, the reactor L and the diode of the upper left IGBT module form a loop, and the current on the reactor will decrease; observe its turn-off waveform with an oscilloscope ;

8) After a period of time, send a PWM pulse to the tested IGBT T3 again, T3 is turned on again, and the current on the reactor will continue to rise on the basis of I _M , until it increases to the peak value of the set current of the device, and observe its conduction through an oscilloscope. pass waveform;

9) If there is no abnormality in the IGBT module, block the PWM pulse of the IGBT under test, turn off T3, and observe its turn-off waveform with an oscilloscope;

10) After the IGBT module under test has undergone the turn-on-off-turn-on-off process, the module is intact, so far, the double pulse test is over.

The method of the present invention is described in detail below through specific examples. The double-pulse test platform is shown in Figure 1. The test circuit is an H-bridge circuit structure, and the tested IGBT module is two tubes of the model FZ1500R33HE3 connected in parallel. Measure the Vce voltage with a high-voltage isolation probe, measure the Vge voltage with an ordinary probe, and measure the current of the tube with a Rogowski coil current probe. Its voltage, current and PWM pulse waveform are shown in Figure 2.

Set the DC bus voltage to 1600V; set the current to 3000A at the edge of the safe working area of the IGBT. Since the two tubes are connected in parallel, the current is 6000A; the inductance value is 1/3mH.

可得Depend on

Available

$\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}$

And then come to

$\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1250</span>}\mathrm{<span\; class="notranslate">\; \&mu;s</span>}$

It can be seen from Figure 2 that to make the current reach 6000A when the second pulse is turned off, the sum of the width of the two pulses is:

T1+T3=1250μs

The specific test steps are:

(1) Carry out the test circuit wiring according to the test circuit diagram 1;

(2) The controller is locked to block the trigger pulses of all IGBTs in the H bridge;

(3) After checking that the wiring is correct, the main circuit is switched on and powered on;

(4) Assuming that the capacitor is very large, charge the DC capacitor to the rated value of 1600V, and the capacitor voltage will remain basically unchanged after charging;

(5) Disconnect the rectification and charging circuit;

(6) T1 and T3 tubes are always in the blocked state, and T2 tube is always in the open state. At time t0, the controller is unlocked, and the first PWM pulse is sent to the tested IGBT module, and T3 is saturated and turned on, so the DC capacitance C and reactance The reactor L and the upper right IGBTT2 form a loop, and the current on the reactor increases linearly until it reaches the peak value of the rated current of the device 3000A, and the waveform when it is turned on is observed through an oscilloscope;

(7) If there is no abnormality in the IGBT module, the PWM pulse of the IGBT under test is blocked at time t1, T3 is turned off, the reactor L and the diode of the upper left IGBT module form a loop, and the current on the reactor will decrease, as shown in Figure 2 As shown by the dotted line in the middle, observe its turn-off waveform through an oscilloscope;

(8) After a period of time, send a PWM pulse to the IGBT T3 under test again at time t2, T3 is saturated and turned on again, the freewheeling diode enters reverse recovery, and the reverse recovery current will pass through the IGBT, which can be captured on the current probe This current, as shown in Figure 2; the current on the reactor will continue to rise on the basis of about 3000A, until it increases to 6000A, the peak value of twice the rated current of the device, and observe its conduction waveform through an oscilloscope;

(9) If there is no abnormality in the IGBT module, the PWM pulse of the IGBT under test is blocked at time t3, and T3 is turned off. At this time, the current is relatively large. Due to the existence of stray inductance, a certain voltage spike will be generated, and it is observed through an oscilloscope Its turn-off waveform;

(10) After the IGBT module under test has undergone the on-off-on-off process, the module is intact and the main circuit is powered off;

(11) So far, the double pulse test is over.

The invention has been described herein in terms of specific exemplary embodiments. Appropriate substitutions or modifications will be apparent to those skilled in the art without departing from the scope of the present invention. The exemplary embodiments are illustrative only, and not limiting of the scope of the invention, which is defined by the appended claims.

Claims (1)

1. a double pulse test method of IGBT module, is characterized in that comprising the following steps: (1) Determine the test circuit; Determine a suitable circuit structure to simulate the actual working state of the insulated gate bipolar transistor IGBT module; the circuit structure is a double-pulse test circuit composed of an IGBT module, and the double-pulse test circuit includes a power supply, a switch, a voltage regulator transformer, transformer, rectifier bridge, DC capacitor, busbar, radiator, reactor, H-bridge IGBT module; the DC capacitor acts as a voltage support, and the DC capacitor is connected to the H-bridge IGBT module through the busbar; the H-bridge IGBT The module is installed on the radiator; the power supply is connected to the rectifier bridge after passing through the switch, voltage regulator and transformer, and the DC capacitor is charged after the AC is converted into DC; the reactor is used as the inductive load of the H-bridge IGBT module and connected to the H-bridge The output terminal of the IGBT module; the H-bridge IGBT module includes the first IGBT (T1), the second IGBT (T2), the third IGBT (T3) and the fourth IGBT (T4), wherein the third IGBT (T3) is Measure IGBT; (2) According to the test circuit and parameters, calculate the pulse width of pulse width modulation PWM; After the test circuit is determined, according to the parameters of the components in the circuit, the formula

Calculate the width of the trigger pulse required for the tested IGBT to reach the target value; (3) Perform correct wiring according to the test circuit; Conduct wiring according to the test circuit, connect the power supply after confirming that the wiring is correct, so as to ensure the safety of the test; (4) Block the pulse width modulation PWM pulse of the IGBT module; Lock the controller and block the trigger pulses of all IGBTs in the H-bridge IGBT module; (5) Charge the DC capacitor to the rated value; Slowly adjust the voltage regulator to charge the DC capacitor through the rectifier bridge until the rated value of the DC capacitor is reached; (6) Disconnect the charging circuit; When the DC capacitor reaches the rated value, the capacitor voltage remains basically unchanged, and the charging circuit is disconnected; (7) Create test conditions; Send a continuous conduction signal to the second IGBT (T2), and the second IGBT (T2) is continuously turned on; (8) Send pulse width modulated PWM pulses to the third IGBT (T3) under test; Unlock the controller, and send a PWM pulse to the third IGBT (T3) under test according to the pulse width calculated in step (2) to make it in the on state; (9) When the third IGBT (T3) under test reaches the rated current value, block the PWM pulse; After the third IGBT (T3) under test is turned on, the DC capacitor, the second IGBT (T2), the load and the third IGBT (T3) form a loop, and the current on the load increases linearly until it reaches the third IGBT (T3) under test. The rated current peak value I _M blocks the PWM pulse, thereby turning off the third IGBT (T3) under test; (10) After a period of time, send PWM pulses to the third IGBT (T3) under test again; After the third IGBT (T3) under test is turned off, the current on the load will decrease slightly. After a period of time, calculate the pulse width according to the method in step (2), and send the pulse width to the third IGBT (T3) under test again. PWM pulse to turn it on; (11) When the third IGBT (T3) under test reaches the set off current value, block the PWM pulse; After the third IGBT (T3) under test is turned on, the current on the load will continue to increase linearly on the basis of I _M until it reaches the peak value of the turn-off current set by the third IGBT (T3) under test, and the PWM will be blocked. pulse, the third IGBT (T3) under test is turned off again; (12) If the third IGBT (T3) under test is intact during the whole process, the test circuit is powered off; Under the condition of rated DC voltage or higher than the rated DC voltage, after the tested third IGBT (T3) has withstood the test process of turn-on-off-turn-on-off peak current, if the tested IGBT module is intact during the whole process, then The test circuit is powered off; (13) The test is over.

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