A system for dynamic and short-circuit testing of smart power modules

Abstract

This invention discloses a system for dynamic and short-circuit testing of intelligent power modules, comprising a control module, a drive circuit, and a power circuit. The control module first generates control commands and sends them to the power circuit, then generates control signals and sends them to the drive module; simultaneously, it calculates multiple parameters required for the test items based on received waveform data and the waveform data of the control signals. The drive circuit isolates and processes the control signals before outputting them to the intelligent power module under test, which then turns its IGBTs on or off sequentially. The power circuit connects to each IGBT of the intelligent power module under test, connects the corresponding IGBT's test channels according to the received control commands, collects waveform data of IGBT current and CE terminal voltage during the test, and sends it to the control module. This invention achieves dynamic parameter testing and short-circuit parameter testing of intelligent power module products through automatic channel switching, automated parameter acquisition, and automatic parameter calculation.

Description

Technical Field

[0001] This invention relates to a system for performing dynamic and short-circuit tests on intelligent power modules, belonging to the field of intelligent power module testing technology. Background Technology

[0002] Intelligent Power Modules (IPMs) integrate power switching devices and drive circuits, and also incorporate overcurrent detection circuitry, which can send the detection signal to the CPU or DSP for interrupt processing. It consists of high-speed, low-power dies, optimized gate-level drive circuits, and fast protection circuits. Even in the event of a load fault or improper use, the IPM itself remains undamaged. Verification technology for the short-circuit and dynamic characteristics of IPMs is a key verification technology in the development and design of intelligent power module products. Currently, domestic equipment is primarily for dynamic and short-circuit testing of IGBTs, lacking dynamic testing equipment for IPMs. Therefore, a dynamic and short-circuit testing system with a dedicated IPM interface needs to be designed. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a dynamic and short-circuit testing system for intelligent power modules, so as to realize the dynamic parameter testing and short-circuit parameter testing of intelligent power module products.

[0004] The technical solution of this invention is:

[0005] A system for dynamic and short-circuit testing of intelligent power modules includes a control module, a drive circuit, and a power circuit.

[0006] The control module generates control commands and sends them to the power circuit based on the product information and test items of the intelligent power module under test. After receiving the completion flag signal from the power circuit, it generates control signals and sends them to the drive module. The control module calculates multiple parameters required for the test items based on the received waveform data and the waveform data of the control signals. The test items include dynamic testing and short-circuit testing.

[0007] The drive circuit is used to isolate the control module and the intelligent power module under test; the control signal is the PWM control voltage signal input to the drive circuit, which is isolated and then output to the intelligent power module under test, and the intelligent power module under test turns on or off the IGBT according to the timing sequence.

[0008] The power circuit connects to each IGBT of the intelligent power module under test. According to the received control command, it connects the test channels of the corresponding IGBTs. After the connection is completed, it sends a completion flag signal to the control module. It collects the waveform data of the IGBT current and CE terminal voltage during the test and sends them to the control module.

[0009] Furthermore, the power module includes a data acquisition unit, a capacitor C1, an inductor L1, a power supply, and an oscilloscope;

[0010] The power supply charges capacitor C1 through connecting bus P and N. Capacitor C1 stores energy and provides transient current; inductor L1 provides inductive load.

[0011] The data acquisition unit includes multiple relays, which are combined to control the on / off state of the test channels connected to each IGBT. The data acquisition unit receives control commands and, according to the requirements of the control commands, switches the relays to achieve the required IGBT connection, performs dynamic testing or short-circuit testing, and acquires the waveform data of the IGBT current and CE terminal voltage when connected using an oscilloscope and sends it to the control module.

[0012] Furthermore, during dynamic testing of the intelligent power module under test, the control module calculates multiple parameters based on the received waveform data. The calculation method is as follows:

[0013] Based on the received IGBT current waveform data, the current rise to 10% I is obtained respectively. c Position corresponds to time t2, current rises to 90% I c The position corresponds to time t3, and the current drops to 90% I. c The position corresponds to time t7, and the current drops to 10%I. c The position corresponds to time t8, and the current rises to I. c The position corresponds to time t9, and the current drops to I. c Position corresponding to time t 10 Among them, I c This refers to the rated current of the IGBT;

[0014] Based on the received waveform data of the IGBT's CE terminal voltage, the voltage drops to 10%V is obtained. CE The position corresponds to time t4, when the voltage rises to 10%V. CE The position corresponds to time t6; where V CE This refers to the rated current at the CE terminal of the IGBT.

[0015] Based on the waveform data of the received PWM control signal voltage, the time t1 corresponding to the voltage drop position and the time t5 corresponding to the voltage rise position are obtained respectively.

[0016] The calculation yielded:

[0017] t d(on) =t2-t1

[0018] t on =t3-t1

[0019] tr = t3 - t2

[0020] t c(on) =t4-t2

[0021] t d(off) =t7-t5

[0022] t c(off) =t8-t6

[0023] t off =t8-t5

[0024] t f =t8-t7

[0025] t rr =t 10 -t9

[0026] I rr =I rmax -Ic

[0027]

[0028]

[0029] Among them, t d(on) To enable the delay time, t on t is the turn-on time, tr is the current rise time, and t is the current rise time. c(on) To enable crossover time, t d(off) For the shutdown delay time, t c(off) For the time to turn off the crossover, t off For the shutdown time, t f Let t be the current fall time. rr For reverse recovery time, I rr For reverse recovery current; E off For turn-off losses, I is the IGBT current, and V is the IGBT's collector-emitter voltage; E on This is for activation losses.

[0030] Furthermore, when performing a short-circuit test on the intelligent power module under test, the control module calculates multiple parameters based on the received waveform data. The calculation method is as follows:

[0031] Based on the received IGBT current waveform data, the time from the current drop from the overcurrent protection point to the start of the current decrease is obtained, which is taken as the short-circuit protection delay time t. off(SC) The maximum current value is obtained and used as the short-circuit protection current.

[0032] Furthermore, the data acquisition unit is equipped with ten relays, K1 to K10. Among them, relays K1 and K2 are used to switch the connection of inductor L1 to the P or N terminal of the input bus, relays K3 and K4 are used to switch the connection of the common terminal line to the P or N terminal of the input bus when testing for short circuit, and relays K7, K8, K9, and K10 are used to switch the connection of U, V, W, and B to the middle common terminal, respectively.

[0033] Furthermore, the point where the control signal is connected to the data acquisition unit is the RLY point. When the RLY point is connected to ground, there is voltage in the relay coil, and the relay is turned on. When the control signal is high, the relay is turned on, and when the RLY point is low, the relay is turned off.

[0034] Furthermore, the busbar is used for the connection between capacitor C1 and the smart power module under test, and the interface of the busbar is connected to the PN class of the smart power module under test.

[0035] Furthermore, a PWM control signal is generated and transmitted via a signal generator and an optocoupler; the signal generator is used to generate a dual-pulse PWM control signal, which is then isolated and transmitted to the intelligent power module under test via the optocoupler.

[0036] The advantages of this invention compared to the prior art are:

[0037] (1) This invention achieves automatic switching between channels, automatic acquisition of parameters and automatic calculation of parameters through the design of control circuit and power circuit, and realizes dynamic parameter testing and short-circuit parameter testing of intelligent power module products.

[0038] (2) The present invention has a reasonable structure and hardware design. The busbar is used for the connection between the energy storage capacitor and the product. The interface of the busbar can be connected to the PN level of the product. This design can reduce the area between PN levels, reduce the impact of parasitic inductance on dynamic testing and short-circuit testing, and improve the accuracy of dynamic testing and short-circuit testing of intelligent power modules. Attached Figure Description

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0040] Figure 1 This is a system composition diagram of an embodiment of the present invention;

[0041] Figure 2 This is a flowchart illustrating the operation of an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the human-machine interface tested in an embodiment of the present invention;

[0043] Figure 4 This is a diagram illustrating the parameter calculation in an embodiment of the present invention;

[0044] Figure 5 This is a diagram illustrating the parameter calculation in an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the connection of the dynamic and short-circuit verification circuit in an embodiment of the present invention;

[0046] Figure 7 This is a circuit diagram for the relay-based short-circuit protection according to an embodiment of the present invention;

[0047] Figure 8 The waveform diagram is a test waveform diagram of an embodiment of the present invention;

[0048] Figure 9 This is a circuit diagram of the isolated drive circuit for the intelligent power module according to an embodiment of the present invention;

[0049] Figure 10 This is a relay drive circuit diagram according to an embodiment of the present invention;

[0050] Figure 11 This is a schematic diagram of the intelligent power module structure according to an embodiment of the present invention;

[0051] Figure 12 This is a screenshot of the interface of the dynamic and short-circuit verification system according to an embodiment of the present invention;

[0052] Figure 13 These are screenshots of dynamic testing in an embodiment of the present invention.

[0053] Figure 14 This is a screenshot of a short-circuit test according to an embodiment of the present invention;

[0054] Figure 15 This is a schematic diagram of the system composition according to an embodiment of the present invention;

[0055] Figure 16 This is a schematic diagram of dynamic testing according to an embodiment of the present invention;

[0056] Figure 17 This is a schematic diagram of a short-circuit test according to an embodiment of the present invention. Detailed Implementation

[0057] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0058] This invention proposes a system for dynamic and short-circuit testing of intelligent power modules, such as... Figure 1 As shown, the system includes a control module, a drive circuit, a power circuit, testing equipment, and a host computer. The drive circuit is used to isolate the control module and the intelligent power module under test, performing signal isolation.

[0059] The control module programs the testing equipment based on the product information of the intelligent power module under test, such as... Figure 2 As shown, after the program starts running, basic test information is first entered, including product name, product type, test item, test channel, test voltage, test current, short-circuit test time, etc. Then, click "Select Test Item" to start the test. The device is initialized, and the test channel is switched through relays K1-K10 in the power circuit. The signal generator outputs a control waveform to determine if the waveform is normal. If it is normal, the test channel is selected, and the capacitor is charged. After charging is completed, a control signal is sent, and then the waveform data is read. The parameters are calculated based on the waveform data. After the calculation is completed, the data and waveform are displayed and stored.

[0060] Dynamic testing requires individual testing of each IGBT in the full-bridge circuit, necessitating automatic switching of the system's connections. This invention uses K1-K10 for this switching. K1 and K2 switch the L1 load inductor connection to either the P or N terminal of the input bus. K3 and K4 switch the common terminal line to either the P or N terminal of the input bus during short-circuit testing. K7, K8, K9, and K10 switch U, V, W, and B connections to the intermediate common terminal, respectively. By activating some of the switches K1-K10, a specific IGBT from G1-G6 can be identified as the test object, achieving the necessary test circuit for testing the dynamic or short-circuit characteristics of the IGBT. Specific activation combinations are shown in Tables 1 and 2.

[0061] Table 1 Dynamic Test Relay Activation Table

[0062] Serial Number Test object Open 1 G1 K2, K7, K6 2 G2 K1, K7, K5 3 G3 K2, K8, K6 4 G4 K1, K8, K5 5 G5 K2,K9,K6 6 G6 K1,K9,K5 7 G7 K1, K10, K5

[0063] Table 2 Short-circuit test activation relay table

[0064] Serial Number Test object Open 1 G1 K4, K7, K6 2 G2 K3, K7, K5 3 G3 K4, K8, K6 4 G4 K3, K8, K5 5 G5 K4, K9, K6 6 G6 K3, K9, K5 7 G7 K3, K10, K5

[0065] Power circuits such as Figure 6 As shown, the 7 IGBTs are G1 to G7 ( Figure 11 As shown in the diagram, C1 is the storage capacitor, L1 is the load inductor, and P, N, U, V, W, and B are respectively... Figure 11The product under test has six power terminals. K1-K10 are ten relays with control circuit connection methods, and the control relationships are shown in Tables 1 and 2. Energy is stored through a thin-film capacitor C1 to provide transient high current. A high-voltage relay switches the power module connection method. Inductor L1 provides the inductive load required for the dual-pulse test. K3 and K4 provide the short-circuit condition required for the short-circuit test.

[0066] Figure 16 This diagram illustrates the turn-on current during the U-phase bridge test. By turning on K2 and K7, a current path is created from P to the bridge IGBT chip in G1, and from L1 to N via K2. K6 is used to connect the positive terminal of the oscilloscope probe to measure the voltage V across the IGBT. CE .

[0067] Based on the obtained parameters, such as Figure 3 As shown, according to Figure 13 The oscilloscope reads four channels of time-domain waveform data in sections a, b, and c. Channel 1 shows the IGBT current, channel 2 shows the IGBT's CE terminal voltage, channel 3 shows the PWM control signal input, and channel 4 shows the Fo signal. According to... Figure 4 How to obtain t1~t 10 The values ​​are: t1 is the time corresponding to the position where VCIN decreases; t2 is the time corresponding to the position where I rises to 10% Ic; t3 is the time corresponding to the position where I rises to 90% Ic; t4 is the time corresponding to the position where V decreases to 10% VCE; t5 is the time corresponding to the position where VCIN increases; t6 is the time corresponding to the position where V rises to 10% VCE; t7 is the time corresponding to the position where I decreases to 90% Ic; t8 is the time corresponding to the position where I decreases to 10% Ic; t9 is the time corresponding to the position where I rises to Ic; t 10 Let I be the time corresponding to the position where I drops to Ic.

[0068] Further calculation yields:

[0069] t d(on) =t2-t1

[0070] t on =t3-t1

[0071] tr = t3 - t2

[0072] t c(on) =t4-t2

[0073] t d(off) =t7-t5

[0074] t c(off) =t8-t6

[0075] t off =t8-t5

[0076] t f =t8-t7

[0077] t rr =t 10 -t9

[0078] I rr =I rmax -Ic

[0079] Among them, t d(on) To enable the delay time, t on t is the turn-on time, tr is the current rise time, and t is the current rise time. c(on) To enable crossover time, t d(off) For the shutdown delay time, t c(off) For the time to turn off the crossover, t off For the shutdown time, t f Let t be the current fall time. rr For reverse recovery time, I rr For reverse recovery current; E off For turn-off losses, I is the IGBT current, and V is the IGBT's collector-emitter voltage; E on This is for activation losses. Figure 5 t in off(SC) This is the short-circuit protection delay time, which starts from the Is overcurrent protection point and continues until the current begins to decrease. SC This is the short-circuit protection current; this value represents the maximum current.

[0080] Calculate the turn-off loss, where I is the IGBT current and V is the IGBT's collector-emitter voltage:

[0081]

[0082] Calculate the turn-on loss:

[0083]

[0084] The host computer is used to input product information of the intelligent power module under test and to display parameter data obtained from dynamic testing and short-circuit testing, such as... Figure 3 , 12 As shown. Figure 12 The right side displays the parameter calculation results and test process; the top area shows the parameter settings and function input areas; and the middle area shows the oscilloscope data reading area, bus voltage monitoring area, IC*VC area, and energy integration calculation area. A dynamic test schematic diagram is shown below. Figure 13 As shown, channel 1 is the current input (I), channel 2 is the voltage input (V), channel 3 is the voltage signal from the signal generator, and channel 4 is the output from the source circuit (FO). A short-circuit test diagram is shown below. Figure 14 As shown, the relationship between each channel is... Figure 13 Consistent. The intelligent power module under test used in this embodiment is as follows: Figure 11 As shown, it includes 6 inverter channels and one braking module, realizing IGBT switching control and short-circuit protection.

[0085] like Figure 15 As shown, the test equipment includes a high-voltage power supply, a low-voltage power supply, a signal generator, a 34980 data acquisition unit, and an oscilloscope. The high-voltage power supply is connected to capacitor C1 (P and N pairs). Figure 6 To charge the system, a storage capacitor is needed because the system requires a maximum transient current of 3000A. A low-voltage power supply provides... Figure 1 The drive circuit is powered by a 24V low-voltage power supply, which is converted to four 15V channels via a DC-DC converter before supplying power to the IPM and relays K1-K10. Figure 6 The system controls the supply of a 24V DC power supply and performs the actions of relevant relays according to the program requirements. An oscilloscope is used to acquire the IGBT's current signal (channel 1), voltage signal (channel 2), PWM control voltage signal (channel 3), and FO alarm signal (channel 4). After acquiring the data, the control module transmits it to the computer for processing to obtain the required parameters.

[0086] like Figure 15 As shown, the host computer software sends commands to the signal generator through the control interface. The signal generator generates control signals, which are then received by... Figure 9 The PWM_IN terminal of the drive circuit is connected to the product's control terminal after isolation by the drive circuit. This causes the IGBT to turn on and off according to the signal sequence from the signal generator. When the signal is high, the IGBT is on; when the signal is low, the IGBT is off. For example... Figure 8 The three-channel waveforms shown are generated by the signal generator. The signal generator generates control signals for the tested intelligent power module. The control circuit board provides four isolated 15V power supplies to the tested intelligent power module. The generation and transmission of seven control PWM signals are achieved through the signal generator, optocouplers, and data acquisition unit. The signal generator generates dual-pulse control signals, which are optically isolated for the drive PWM signals. Optical coupling is also used to isolate the FO alarm signal. Figure 9 As shown, the PWM_IN signal generated by the signal generator is isolated by an optocoupler and transmitted to PWM_OUT to provide a control signal to the IPM. The FO signal FO_IN generated by the IPM is transmitted to FO_OUT through optocoupler isolation. The host computer software sends control commands to the 34980, and the 34980 data acquisition device controls the switching on and off of relays K1-K10, such as... Figure 10As shown, the control point RLY is connected to the 34980 control point, and JDQF is connected to the relay's switch control coil. When RLY is connected to ground, there is voltage in the relay coil, and the relay is activated. RLY is... Figure 10 In the control signal input section of the circuit, the relay is activated when the signal is high and deactivated when RLY is low. The high and low states of RLY are controlled by the 34980, whose control source is the host computer software. Since only one signal needs to be sent to the control port of one IPM in a single test, the control signal generated by the signal generator is sent to the channel that needs to be controlled through the relay switching function in the 34908 data acquisition unit. Other channels are in the off state by default. Figure 8 The blue signal represents the control signal waveform.

[0087] A relay-based shoot-through protection circuit was designed, such as... Figure 7 As shown, when RLY1, RLY3, and RLY5 are high, the control terminals of RLY2, RLY4, and RLY6 are automatically pulled low via MOSG2, MOSG4, and MOSG6 to prevent K2, K4, and K6 from conducting when K1, K3, and K5 are conducting, and vice versa. Since the relay groups are connected in pairs on the high-voltage bus, this circuit is designed to prevent short circuits caused by interference signals or misoperation leading to shoot-through of the series relays. The basic principle is that when a relay on the upper or lower bridge is conducting, the circuit automatically blocks the drive signal of the lower bridge, preventing it from conducting. This hardware circuitry prevents the risk of shoot-through due to misoperation.

[0088] According to the activation status in Tables 1 and 2, dynamic tests and short-circuit tests can be performed on G1 to G7 respectively. Dynamic test G1 is as follows: Figure 16 As shown, the short-circuit test of G1 is as follows: Figure 17 As shown.

[0089] The embodiments described above are merely preferred embodiments of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for dynamic and short circuit testing of an intelligent power module, characterized in that The power module comprises a control module, a driving circuit and a power circuit. The control module generates a control signal and sends it to the driving module after receiving a completion signal from the power circuit; the control module calculates a plurality of parameters required by the test item according to the received waveform data; wherein the test item comprises dynamic testing and short circuit testing. The driving circuit is used for isolating the control module and the intelligent power module under test; the control signal is a PWM control voltage signal input to the driving circuit, which is output to the intelligent power module under test after isolation processing; the intelligent power module under test turns on or off the IGBT according to the timing sequence. The power circuit connects each IGBT of the intelligent power module under test; the power circuit connects the test channels of the corresponding IGBT according to the received control instruction; the power circuit sends a completion signal to the control module after the connection is completed; the power circuit collects the waveform data of the current and the voltage at the CE terminal of the IGBT during the test and sends it to the control module. The power module comprises a data collector, a capacitor C1, an inductor L1, a power supply and an oscilloscope; the power supply charges the capacitor C1 through the connection bus P and N; the capacitor C1 stores energy and provides transient current; the inductor L1 provides inductive load; the data collector comprises a plurality of relays; the test channels connected to each IGBT are controlled by the combination of the plurality of relays; the data collector receives the control instruction; the data collector connects the IGBT required by the instruction according to the control instruction requirement; the data collector performs dynamic testing or short circuit testing; the data collector obtains the waveform data of the current and the voltage at the CE terminal of the IGBT during the connection through the oscilloscope and sends it to the control module. The data collector is provided with ten relays K1-K10; wherein the relay K1 and the relay K2 are used to switch the connection of the inductor L1 to the P or N terminal of the input bus; the relay K3 and the relay K4 are used to switch the connection of the common terminal to the P or N terminal of the input bus during the short circuit test; the relay K7, the relay K8, the relay K9 and the relay K10 are used to switch the connection of U, V, W and B to the common terminal. The point where the control signal accesses the data collector is the RLY point; when the RLY point is connected to the ground, there is voltage in the relay coil, and the relay is connected; when the control signal is high, the relay is connected, and when the RLY point is low, the relay is disconnected.

2. The system for dynamic and short circuit testing of an intelligent power module according to claim 1, characterized in that When the intelligent power module under test is dynamically tested, the control module calculates a plurality of parameters according to the received waveform data; the calculation method is as follows: Based on the received IGBT current waveform data, the current rise to 10% I is obtained respectively. c Position corresponds to time t2, current rises to 90% I c The position corresponds to time t3, and the current drops to 90% I. c The position corresponds to time t7, and the current drops to 10%I. c The position corresponds to time t8, and the current rises to I. c The position corresponds to time t9, and the current drops to I. c Position corresponding to time t 10 Among them, I c This refers to the rated current of the IGBT; According to the received waveform data of the CE end voltage of the IGBT, the position corresponding to the moment t4 when the voltage drops to 10% V CE , and the position corresponding to the moment t6 when the voltage rises to 10% V CE are obtained respectively; wherein V CE is the rated current of the CE end of the IGBT. According to the received waveform data of the PWM control signal voltage, the positions corresponding to the time t1 when the voltage drops and the time t5 when the voltage rises are obtained respectively; The calculation result is as follows: t d(on) = t2- t1 t on = t3 - t1 tr=t3-t2 t c(on) = t4 - t2 t d(off) = t7 - t5 t c(off) = t8 - t6 t off = t8 - t5 t f = t8 - t7 t rr = t 10 -t9 I rr =I rmax -Ic Wherein, t d(on) is the turn-on delay time, t on is the turn-on time, t c(on) is the turn-on cross time, t d(off) is the turn-off delay time, t c(off) is the turn-off cross time, t off is the turn-off time, t f is the current fall time, t rr is the reverse recovery time, I rr is the reverse recovery current; E off is the turn-off loss, I is the current of the IGBT, V is the CE terminal voltage of the IGBT; E on is the turn-on loss.

3. The system for dynamic and short circuit testing of an intelligent power module of claim 1, wherein, When the intelligent power module under test is short circuit tested, the control module calculates a plurality of parameters according to the received waveform data; the calculation method is as follows: According to the received IGBT current waveform data, the time from the overcurrent protection point to the start of the decline is obtained as the short-circuit protection delay time t off(SC) ; The maximum current value is obtained as the short circuit protection current.

4. The system for dynamic and short circuit testing of an intelligent power module of claim 1, wherein, The busbar is used for the connection between the capacitor C1 and the intelligent power module under test; the interface of the busbar is connected to the PN level of the intelligent power module under test.

5. The system for dynamic and short circuit testing of an intelligent power module of claim 1, wherein, The PWM control signal is generated and sent through a signal generator and an optical coupler; the signal generator is used for generating a double-pulse PWM control signal, and the double-pulse PWM control signal is transmitted to the measured intelligent power module through the optical coupler.

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