Power module test circuit

Abstract

The utility model discloses a power module test circuit passes through the design contactor, safety interlock loop, safety interlock loop includes any one or more in overtemperature protection circuit, overvoltage protection circuit, and overtemperature protection circuit detects the temperature of power module to exceed temperature threshold value, controls the coil of contactor and power off, prevents the temperature of power module and be too high, and overvoltage protection circuit detects the bus voltage of power module to exceed voltage threshold value, controls the coil of contactor and power off, prevents the bus voltage and be too high. Therefore, the utility model discloses a power module test circuit passes through the design contactor and safety interlock loop, and the safety of circuit has been improved, and the technical problem of poor safety in the prior art has been solved.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, and in particular to a power module test circuit. Background Technology

[0002] In circuit design, the parameter characteristics of devices are usually understood through the technical manuals provided by the manufacturer. However, the parameters provided in the manuals are measured under specific conditions, which may differ from actual operating conditions, and therefore cannot be used directly. Therefore, testing the switching characteristics of power devices by applying two pulses allows for a more accurate evaluation.

[0003] Currently, the testing methods for power components in the industry have shortcomings in terms of both safety and operability. When testing or debugging power devices, there is a risk of device failure leading to excessive voltage or current at the downstream end, resulting in a "power explosion." There are also short circuits caused by wiring issues during the initial debugging process, which affect the safety of testers and testing equipment. Summary of the Invention

[0004] This invention proposes a power module testing circuit, which solves the technical problem of poor safety in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This utility model provides a power module testing circuit, including:

[0007] The contactor has its normally open contacts connected in series in the power supply line between the power supply and the power module;

[0008] A safety interlock circuit, which includes one or more of the following protection circuits;

[0009] An over-temperature protection circuit is used to detect the temperature of the power module and, when the detected temperature exceeds the temperature threshold, controls the coil of the contactor to be de-energized.

[0010] An overvoltage protection circuit is used to detect the bus voltage of the power module. When the bus voltage exceeds the voltage threshold, it controls the coil of the contactor to be de-energized.

[0011] In some embodiments of this application, the over-temperature protection circuit includes a temperature detection module, an amplifier circuit, a first comparator, a first switching circuit, and a first relay;

[0012] The temperature detection module detects the temperature of the power module and sends the detected temperature signal to the amplification circuit. The amplification circuit amplifies the received signal and sends it to the first comparator. The first comparator compares the received temperature signal with a reference temperature. The output of the first comparator is connected to the control terminal of the first switching circuit. The switching path of the first switching circuit is connected in series in the power supply circuit of the coil of the first relay. The normally closed contact of the first relay is connected in series in the power supply circuit of the coil of the contactor. The ratio of the reference temperature to the temperature threshold is equal to the amplification factor of the amplification circuit.

[0013] In some embodiments of this application, the first switching circuit includes a first switching transistor, a second switching transistor, and a first optocoupler;

[0014] The control terminal of the first switching transistor is connected to the output terminal of the first comparator. The switching path of the first switching transistor is connected in series in the power supply circuit of the light-emitting terminal of the first optocoupler. The input terminal of the light-receiving terminal of the first optocoupler is connected to a DC power supply. The output terminal of the light-receiving terminal of the first optocoupler is connected to the control terminal of the second switching transistor. The switching path of the second switching transistor is connected in series in the power supply circuit of the coil of the first relay.

[0015] In some embodiments of this application, the overvoltage protection circuit includes a transformer, a second comparator, a second switching circuit, and a second relay;

[0016] The transformer steps down the bus voltage of the power module and inputs it to the second comparator. The second comparator compares the received voltage with the reference voltage. The output of the second comparator is connected to the control terminal of the second switching circuit. The switching path of the second switching circuit is connected in series in the power supply circuit of the coil of the second relay. The normally closed contact of the second relay is connected in series in the power supply circuit of the coil of the contactor. The ratio of the voltage threshold to the reference voltage is equal to the step-down ratio of the transformer.

[0017] In some embodiments of this application, the second switching circuit includes a third switching transistor, a fourth switching transistor, and a second optocoupler;

[0018] The control terminal of the third switch is connected to the output terminal of the second comparator. The switching path of the third switch is connected in series in the power supply circuit of the light-emitting terminal of the second optocoupler. The input terminal of the light-receiving terminal of the second optocoupler is connected to a DC power supply. The output terminal of the light-receiving terminal of the second optocoupler is connected to the control terminal of the fourth switch. The switching path of the fourth switch is connected in series in the power supply circuit of the coil of the second relay.

[0019] In some embodiments of this application, the safety interlocking circuit further includes:

[0020] An overcurrent protection circuit is used to detect the current of the power module and, when the detected current exceeds the current threshold, controls the coil of the contactor to be de-energized.

[0021] In some embodiments of this application, the overcurrent protection circuit includes a current transformer and a thermal relay;

[0022] The current transformer collects the output current of the power module, the thermal relay is connected in parallel across the current transformer, and the normally closed contact of the thermal relay is connected in series in the power supply circuit of the contactor coil.

[0023] In some embodiments of this application, the safety interlocking circuit further includes:

[0024] An emergency stop switch is connected in series in the power supply circuit of the contactor coil.

[0025] In some embodiments of this application, the power module test circuit further includes:

[0026] A voltage regulator is used to change the voltage output by a power supply.

[0027] In some embodiments of this application, the driving circuit of the power module includes:

[0028] A signal generator that produces pulse signals;

[0029] A drive signal conversion circuit converts the pulse signal generated by the signal generator into a pulse drive signal;

[0030] The interface board sends the pulse drive signal generated by the drive signal conversion circuit to the drive board for driving the power module.

[0031] The technical solution of this utility model has the following technical advantages over the prior art: The power module test circuit of this utility model, through the design of a contactor and a safety interlock circuit, includes one or more of an over-temperature protection circuit and an over-voltage protection circuit. When the over-temperature protection circuit detects that the temperature of the power module exceeds a temperature threshold, it controls the contactor coil to de-energize, preventing the power module from overheating. When the over-voltage protection circuit detects that the bus voltage of the power module exceeds a voltage threshold, it controls the contactor coil to de-energize, preventing the bus voltage from over-voltage. Therefore, the power module test circuit of this utility model, through the design of a contactor and a safety interlock circuit, improves the safety of the circuit and solves the technical problem of poor safety in the prior art.

[0032] Other features and advantages of this utility model will become clearer after reading the detailed embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a circuit diagram of one embodiment of the power module test circuit of this utility model;

[0035] Figure 2 A circuit diagram of one embodiment of an over-temperature protection circuit;

[0036] Figure 3 A circuit schematic diagram of one embodiment of an over-temperature protection circuit;

[0037] Figure 4 A circuit schematic diagram of one embodiment of an overvoltage protection circuit;

[0038] Figure 5 This is a circuit diagram of yet another embodiment of the power module test circuit;

[0039] Figure 6 A circuit diagram of one embodiment of a thermal relay;

[0040] Figure 7 A circuit diagram of one embodiment of a safety interlocking circuit;

[0041] Figure 8 A circuit diagram of one embodiment of the driving circuit;

[0042] Figure 9 An overall block diagram of one embodiment of a power module test circuit;

[0043] Figure 10 This is a circuit diagram of one phase of the power module. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0049] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0050] The power module test circuit in this embodiment includes a contactor, a safety interlock circuit, etc.; the safety interlock circuit includes one or more of an over-temperature protection circuit and an over-voltage protection circuit, see [link to relevant documentation]. Figure 1 As shown.

[0051] The contactor has its normally open contacts connected in series in the power supply line between the power supply and the power module.

[0052] Safety interlock circuit, which includes one or more of the following protection circuits.

[0053] The over-temperature protection circuit is used to detect the temperature of the power module. When the detected temperature exceeds the temperature threshold, it controls the coil of the contactor to be de-energized, and the normally open contact of the contactor opens, thus disconnecting the power supply line between the power supply and the power module to prevent the power module from overheating.

[0054] The overvoltage protection circuit is used to detect the bus voltage of the power module. When the bus voltage exceeds the voltage threshold, it controls the coil of the contactor to be de-energized, and the normally open contact of the contactor opens, thus disconnecting the power supply line between the power supply and the power module to prevent the bus voltage of the power module from being too high.

[0055] The power module test circuit of this embodiment improves circuit safety by incorporating a contactor and a safety interlock circuit. The safety interlock circuit includes one or more of an over-temperature protection circuit and an over-voltage protection circuit. When the over-temperature protection circuit detects that the power module's temperature exceeds a temperature threshold, it de-energizes the contactor coil to prevent the power module from overheating. Similarly, when the over-voltage protection circuit detects that the power module's bus voltage exceeds a voltage threshold, it de-energizes the contactor coil to prevent the bus voltage from over-voltage. Therefore, the power module test circuit of this embodiment, through the design of the contactor and safety interlock circuit, enhances circuit safety and solves the technical problem of poor safety in existing technologies.

[0056] In some embodiments of this application, the over-temperature protection circuit includes a temperature detection module, an amplifier circuit U13A, a first comparator U12B, a first switching circuit, a first relay RLY3, etc., see [link to relevant documentation]. Figure 2 , 3 As shown.

[0057] The temperature detection module detects the temperature of the power module and sends the detected temperature signal to the amplification circuit. The amplification circuit amplifies the received signal and sends it to the first comparator U12B. The first comparator U12B compares the received temperature signal with a reference temperature. The output of the first comparator U12B is connected to the control terminal of the first switching circuit. The switching path of the first switching circuit is connected in series in the power supply circuit of the coil of the first relay RLY3. The normally closed contact of the first relay RLY3 is connected in series in the power supply circuit of the contactor coil. The ratio of the reference temperature to the temperature threshold is equal to the amplification factor of the amplification circuit.

[0058] When the temperature of the power module exceeds the temperature threshold, the first comparator U12B compares the received temperature signal and finds it to be greater than the reference temperature. It then outputs a high level to the control terminal of the first switching circuit, which turns on the switch path. The coil of the first relay RLY3 is energized, and the normally closed contact of the first relay RLY3 opens, disconnecting the power supply circuit of the contactor coil. In other words, the contactor coil is de-energized, and the normally open contact of the contactor opens, disconnecting the power supply line between the power supply and the power module.

[0059] When the temperature of the power module is lower than the temperature threshold, the first comparator U12B compares the received temperature signal and finds that it is lower than the reference temperature. It then outputs a low level to the control terminal of the first switching circuit, disconnects the switching path of the first switching circuit, de-energizes the coil of the first relay RLY3, and closes the normally closed contact of the first relay RLY3.

[0060] By designing the over-temperature protection circuit with the above structure, it is not only convenient to detect whether the temperature of the power module exceeds the temperature threshold, but also the circuit structure is simple, easy to implement, and low in cost.

[0061] The temperature detection module can directly detect the temperature of the power module, or indirectly obtain the temperature of the power module by detecting the temperature of the power module's heat sink.

[0062] In some embodiments of this application, the first switching circuit includes a first switching transistor T8, a second switching transistor T7, a first optocoupler U11, etc., see [link / reference]. Figure 3 As shown.

[0063] The control terminal of the first switch transistor T8 is connected to the output terminal of the first comparator U12B. The switching path of the first switch transistor T8 is connected in series in the power supply circuit of the light-emitting terminal of the first optocoupler U11. The input terminal of the light-receiving terminal of the first optocoupler U11 is connected to a DC power supply (such as a 24V DC power supply). The output terminal of the light-receiving terminal of the first optocoupler U11 is connected to the control terminal of the second switch transistor T7. The switching path of the second switch transistor T7 is connected in series in the power supply circuit of the coil of the first relay RLY3.

[0064] When the output of the first comparator U12B outputs a high level to the control terminal of the first switch T8, the switching path of the first switch T8 is turned on, the power supply circuit of the light-emitting terminal of the first optocoupler U11 is turned on, and the light-receiving terminal of the first optocoupler U11 is turned on, causing the control terminal of the second switch T7 to be at a high level and the switching path of the second switch T7 to be turned on. This causes the power supply circuit of the coil of the first relay RLY3 to be turned on, the coil of the first relay RLY3 to be energized, and the normally closed contact of the first relay RLY3 to be opened, disconnecting the power supply circuit of the contactor coil, that is, the contactor coil is de-energized, and the normally open contact of the contactor is opened, disconnecting the power supply line between the power supply and the power module.

[0065] When the output of the first comparator U12B is low and the control terminal of the first switch T8 is reached, the first switch T8 is turned off, the first optocoupler U11 is turned off, the second switch T7 is turned off, the coil of the first relay RLY3 is de-energized, and the normally closed contact of the first relay RLY3 is closed.

[0066] By designing the first switching circuit with the above structure, it is convenient to control whether the coil of the first relay RLY3 is energized or not. Moreover, the circuit structure is simple, easy to implement, and low in cost.

[0067] In some embodiments of this application, the overvoltage protection circuit includes a transformer, a second comparator U8B, a second switching circuit, a second relay RLY2, etc., see [link to relevant documentation]. Figure 4 As shown.

[0068] The transformer steps down the bus voltage Udc of the power module and inputs it to the second comparator U8B. The second comparator U8B compares the received voltage with a reference voltage. The output of the second comparator U8B is connected to the control terminal of the second switching circuit. The switching path of the second switching circuit is connected in series in the power supply circuit of the coil of the second relay RLY2. The normally closed contact of the second relay RLY2 is connected in series in the power supply circuit of the contactor coil. The ratio of the voltage threshold to the reference voltage is equal to the transformer's step-down ratio.

[0069] When the bus voltage is greater than the voltage threshold, the second comparator U8B compares the received voltage and finds that it is greater than the reference voltage. It then outputs a high level to the control terminal of the second switching circuit, which turns on the switching path of the second switching circuit. The coil of the second relay RLY2 is energized, and the normally closed contact of the second relay RLY2 opens, disconnecting the power supply circuit of the contactor coil. In other words, the contactor coil is de-energized, and the normally open contact of the contactor opens, disconnecting the power supply line between the power supply and the power module.

[0070] When the bus voltage is less than the voltage threshold, the second comparator U8B compares the received voltage and finds that it is less than the reference voltage. It then outputs a low level to the control terminal of the second switching circuit, disconnects the switching path of the second switching circuit, de-energizes the coil of the second relay RLY2, and closes the normally closed contact of the second relay RLY2.

[0071] By designing the overvoltage protection circuit with the above structure, it is not only convenient to detect whether the bus voltage exceeds the voltage threshold, but also the circuit structure is simple, easy to implement, and low in cost.

[0072] In some embodiments of this application, the second switching circuit includes a third switching transistor T6, a fourth switching transistor T5, a second optocoupler U7, etc., see [link / reference]. Figure 4 As shown.

[0073] The control terminal of the third switch transistor T6 is connected to the output terminal of the second comparator U8B. The switching path of the third switch transistor T6 is connected in series in the power supply circuit of the light-emitting terminal of the second optocoupler U7. The input terminal of the light-receiving terminal of the second optocoupler U7 is connected to a DC power supply (such as a 24V DC power supply). The output terminal of the light-receiving terminal of the second optocoupler U7 is connected to the control terminal of the fourth switch transistor T5. The switching path of the fourth switch transistor T5 is connected in series in the power supply circuit of the coil of the second relay RLY2.

[0074] When the output of the second comparator U8B is high, the control terminal of the third switch T6 is activated, the switching path of the third switch T6 is turned on, the power supply circuit of the light-emitting terminal of the second optocoupler U7 is turned on, and the light-receiving terminal of the second optocoupler U7 is turned on. This causes the control terminal of the fourth switch T5 to be high, and the switching path of the fourth switch T5 to be turned on. This, in turn, causes the power supply circuit of the coil of the second relay RLY2 to be turned on. The coil of the second relay RLY2 is energized, and the normally closed contact of the second relay RLY2 is opened, disconnecting the power supply circuit of the contactor coil. That is, the contactor coil is de-energized, and the normally open contact of the contactor is opened, disconnecting the power supply line between the power supply and the power module.

[0075] When the output of the second comparator U8B is low and the control terminal of the third switch T6 is reached, the third switch T6 is turned off, the second optocoupler U7 is turned off, the fourth switch T5 is turned off, the coil of the second relay RLY2 is de-energized, and the normally closed contact of the second relay RLY2 is closed.

[0076] By designing the second switching circuit with the above structure, it is convenient to control whether the coil of the second relay RLY2 is energized or not. Moreover, the circuit structure is simple, easy to implement, and low in cost.

[0077] In some embodiments of this application, the safety interlock circuit further includes an overcurrent protection circuit.

[0078] The overcurrent protection circuit is used to detect the current of the power module. When the detected current exceeds the current threshold, it controls the coil of the contactor to be de-energized, and the normally open contact of the contactor opens, thus disconnecting the power supply line between the power supply and the power module to prevent the power module from accumulating excessive current.

[0079] When the overcurrent protection circuit detects that the current of the power module exceeds the current threshold, it controls the contactor coil to cut off the power to prevent the current of the power module from being too high and improve the circuit safety.

[0080] In some embodiments of this application, the overcurrent protection circuit includes a current transformer and a thermal relay FR.

[0081] The current transformer collects the output current of the power module. The thermal relay FR is connected in parallel across the current transformer. The normally closed contact of the thermal relay FR is connected in series in the power supply circuit of the contactor coil.

[0082] For example, a power module is an inverter module, which includes multiple power devices.

[0083] See Figure 5 As shown, current transformer TA1 is used to collect the U-phase output current of the inverter module. Current transformer TA1 has terminal A1 and terminal PE1, with terminal PE1 grounded.

[0084] Current transformer TA2 is used to collect the V-phase output current of the inverter module. Current transformer TA2 has terminals A2 and PE2, with terminal PE2 grounded.

[0085] Current transformer TA3 is used to collect the W-phase output current of the inverter module. Current transformer TA3 has terminals A3 and PE3, with terminal PE3 grounded.

[0086] See Figure 6 As shown, terminals A1 and PE1 of the thermal relay FR are connected to terminals A1 and PE1 of the current transformer TA1.

[0087] Terminals A2 and PE2 of the thermal relay FR are connected to terminals A2 and PE2 of the current transformer TA2.

[0088] Terminals A3 and PE3 of the thermal relay FR are connected to terminals A3 and PE3 of the current transformer TA3.

[0089] When the current detected by the current transformer exceeds the current threshold, the normally closed contact of the thermal relay FR opens, disconnecting the power supply circuit of the contactor coil, that is, the contactor coil is de-energized, and the normally open contact of the contactor opens, disconnecting the power supply line between the power supply and the power module.

[0090] By designing the above overcurrent protection circuit, it is not only convenient to detect whether the output current of the power module exceeds the current threshold, but also the circuit structure is simple, easy to implement, and low in cost.

[0091] In some embodiments of this application, the safety interlocking circuit further includes an emergency stop switch SB.

[0092] The emergency stop switch SB is connected in series in the power supply circuit of the contactor coil.

[0093] In an emergency, pressing the emergency stop switch SB quickly cuts off the power supply circuit to the contactor coil, de-energizing the contactor coil and opening the normally open contacts of the contactor, thus ensuring the safety of the downstream circuit.

[0094] See Figure 7 As shown, the normally closed contact of the emergency stop switch SB, the normally closed contact of the thermal relay FR, the normally closed contact of the first relay RLY3, and the normally closed contact of the second relay RLY2 are connected in series in the power supply circuit of the coil of the contactor KM.

[0095] In the event of any emergency, overcurrent of the power module output current, overheating of the power module, or overvoltage of the bus voltage, the power supply to the contactor KM coil can be disconnected, causing the normally open contacts of the contactor KM to open and ensuring circuit safety.

[0096] In some embodiments of this application, the power module test circuit also includes a voltage regulator.

[0097] A voltage regulator is used to change the voltage output by a power supply.

[0098] The power supply is an externally input three-phase power supply, which can be converted into an adjustable three-phase power supply from 0 to 750V through a voltage regulator.

[0099] By flexibly changing the input voltage of the power module, gradually increasing it from below the safe voltage for the human body to the test voltage required for dual pulses, the safety of personnel operating the equipment can be ensured.

[0100] In some embodiments of this application, the driving circuit of the power module includes a signal generator, a driving signal conversion circuit, an interface board, etc., see [link to relevant documentation]. Figure 8 As shown.

[0101] A signal generator that produces low-level pulse signals;

[0102] The drive signal conversion circuit converts the pulse signal generated by the signal generator into a pulse drive signal;

[0103] The interface board sends the pulse drive signal generated by the drive signal conversion circuit to the drive board to drive the power module.

[0104] By designing a signal generator, a drive signal conversion circuit, and an interface board, the safety and scalability of the entire circuit were improved.

[0105] The power module's driver board is controlled using a combination of a signal generator, a drive signal conversion circuit, and an interface board. The drive signal conversion circuit effectively isolates the signal generator from the power module, preventing damage to the signal generator from surges, and also enables voltage conversion, allowing low-signal control of the driver board.

[0106] An interface board is used to multiplex control signals, which can simultaneously drive multiple power modules connected in parallel, avoiding redundant wiring and providing strong scalability. This application describes a three-channel parallel power module, but is not limited to three-channel parallel connection.

[0107] By using a control method consisting of a signal generator, a drive signal conversion circuit, and an interface board, the safety and scalability of the entire test circuit are further improved, allowing it to be extended to scenarios where multiple power modules are connected in parallel.

[0108] In some embodiments of this application, the drive signal conversion circuit is a gate drive optocoupler.

[0109] Figure 8 In the process, the low-level pulse signals U+ and U- from the signal generator are converted into the voltage that can drive the power module after passing through the drive signal conversion circuit, which is the pulse drive signal Ui.

[0110] The drive signal conversion circuit uses a gate-driven optocoupler U10, which can achieve rail-to-rail output and has high isolation voltage, which can effectively protect the signal generator from the impact of the subsequent circuit.

[0111] The power module of this application includes several power devices.

[0112] For example, a power module is an inverter module, which includes multiple power devices.

[0113] This application focuses on inverter modules, but its application is not limited to inverter modules; it includes the testing of all power devices (such as IGBTs, MOSFETs, and SSiC / GaN devices).

[0114] The power module test circuit in this embodiment includes a power supply (three-phase power supply), voltage regulator, circuit breaker, AC contactor, safety interlock circuit (including emergency stop switch, overcurrent protection circuit, overvoltage protection circuit, and overtemperature protection circuit), rectifier bridge, filter capacitor, power module (such as inverter module), signal generator, 15V switching power supply, drive signal conversion circuit, interface board, driver board, etc. (See also...) Figure 9 As shown.

[0115] The externally input three-phase power supply can be converted into an adjustable three-phase power supply from 0 to 750V through a voltage regulator. By flexibly changing the input voltage of the inverter module, it gradually increases from below the human safety voltage to the test voltage required for the dual pulse, ensuring the safety of personnel operating the equipment. A circuit breaker serves as another layer of protection on the input side, ensuring that the test system is free from short-circuit and overload risks. The voltage reaches the AC contactor after passing through the circuit breaker. The AC contactor is the core component of this application's multiple safety interlocking system. The interlocking protection circuit controls the contactor coil to achieve the engagement or disengagement of the subsequent circuits. When the hardware circuit triggers the protection, it can safely and reliably cut off the fault current or load current. The three-phase input voltage of the rectifier bridge is controlled by the AC contactor, protecting the safety and reliability of the subsequent circuits. The DC bus voltage obtained from the rectifier bridge is filtered by a filter capacitor and then transmitted to the three-phase inverter module for inverter output.

[0116] The explanation will focus on one phase of the three-phase output of the inverter module, such as... Figure 10 As shown, the pulse drive signal Ui is split into three and transmitted to the drive board after passing through the interface board. It is used to drive the lower transistor of the three-phase parallel inverter module. The Vce voltage is taken with a high-voltage isolation probe, the Io current is taken with a Rogowski coil current probe, and the Vge1 to Vge3 signals are measured with a common probe.

[0117] The 380V three-phase power supply is sent to the voltage regulator after passing through the circuit breaker QF. The three-phase voltage regulator can achieve a three-phase voltage output of 0-750V. For the first double-pulse experiment of power devices, the input voltage of the inverter module can be flexibly changed, gradually increasing from below the human safety voltage to the test voltage required for the double pulse. After multiple rounds of debugging and verification, the voltage level can be gradually increased to complete the experiment, ensuring the safety of personnel operating the equipment. The AC contactor KM is the actuator of the multiple safety interlocking proposed in this application. When the hardware circuit triggers the protection, it can safely and reliably cut off the fault current or load current. Three current sensors are configured on the output side U, V, and W of the inverter module to detect overload or short circuit at the load output terminal, and the feedback is sent to the multiple safety interlocking circuit through a thermal relay.

[0118] In the safety interlock circuit, the emergency stop switch SB acts as a button in emergencies, quickly cutting off the downstream circuit by pressing the switch. The overcurrent protection circuit (thermal relay FR and current transformer) protects the circuit by detecting overload or short-circuit overcurrent at the load output. The overtemperature protection circuit detects the temperature of the heat sinks of the three-phase U, V, and W inverter modules to determine if the inverter modules are overheating during testing, and then cuts off the main power supply circuit via the AC contactor. The overvoltage protection circuit detects whether there is overvoltage Udc on the bus, and then switches the AC contactor coil on and off.

[0119] In the safety interlocking circuit, when any protection circuit is triggered, the control AC contactor coil is de-energized, causing it to disconnect the downstream circuit. Furthermore, by using an AC contactor to control the input voltage of the rectifier bridge, the fault current or load current can be safely and reliably interrupted when the hardware circuit triggers protection.

[0120] The power module test circuit of this application is an AC contactor segmented circuit based on multiple safety interlocks, avoiding the dangers caused by power module failure. Secondly, the control method of signal generator + drive signal conversion circuit + interface board further improves the safety and scalability of the entire test system, allowing it to be extended to scenarios with multiple power modules connected in parallel. Simultaneously, it also solves the drawback of high-voltage debugging in current power module testing processes, using a debugging process that gradually increases the voltage from below the human body safety voltage to the test voltage required for the dual pulse, ensuring the safety of personnel operating the equipment.

[0121] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0122] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A power module test circuit, characterized in that, include: The contactor has its normally open contacts connected in series in the power supply line between the power supply and the power module; A safety interlock circuit, which includes one or more of the following protection circuits; An over-temperature protection circuit is used to detect the temperature of the power module and, when the detected temperature exceeds the temperature threshold, controls the coil of the contactor to be de-energized. An overvoltage protection circuit is used to detect the bus voltage of the power module. When the bus voltage exceeds the voltage threshold, it controls the coil of the contactor to be de-energized.

2. The power module test circuit according to claim 1, characterized in that: The over-temperature protection circuit includes a temperature detection module, an amplifier circuit, a first comparator, a first switching circuit, and a first relay; The temperature detection module detects the temperature of the power module and sends the detected temperature signal to the amplification circuit. The amplification circuit amplifies the received signal and sends it to the first comparator. The first comparator compares the received temperature signal with a reference temperature. The output of the first comparator is connected to the control terminal of the first switching circuit. The switching path of the first switching circuit is connected in series in the power supply circuit of the coil of the first relay. The normally closed contact of the first relay is connected in series in the power supply circuit of the coil of the contactor. The ratio of the reference temperature to the temperature threshold is equal to the amplification factor of the amplification circuit.

3. The power module test circuit according to claim 2, characterized in that: The first switching circuit includes a first switching transistor, a second switching transistor, and a first optocoupler; The control terminal of the first switching transistor is connected to the output terminal of the first comparator. The switching path of the first switching transistor is connected in series in the power supply circuit of the light-emitting terminal of the first optocoupler. The input terminal of the light-receiving terminal of the first optocoupler is connected to a DC power supply. The output terminal of the light-receiving terminal of the first optocoupler is connected to the control terminal of the second switching transistor. The switching path of the second switching transistor is connected in series in the power supply circuit of the coil of the first relay.

4. The power module test circuit according to claim 1, characterized in that: The overvoltage protection circuit includes a transformer, a second comparator, a second switching circuit, and a second relay; The transformer steps down the bus voltage of the power module and inputs it to the second comparator. The second comparator compares the received voltage with the reference voltage. The output of the second comparator is connected to the control terminal of the second switching circuit. The switching path of the second switching circuit is connected in series in the power supply circuit of the coil of the second relay. The normally closed contact of the second relay is connected in series in the power supply circuit of the coil of the contactor. The ratio of the voltage threshold to the reference voltage is equal to the step-down ratio of the transformer.

5. The power module test circuit according to claim 4, characterized in that: The second switching circuit includes a third switching transistor, a fourth switching transistor, and a second optocoupler; The control terminal of the third switch is connected to the output terminal of the second comparator. The switching path of the third switch is connected in series in the power supply circuit of the light-emitting terminal of the second optocoupler. The input terminal of the light-receiving terminal of the second optocoupler is connected to a DC power supply. The output terminal of the light-receiving terminal of the second optocoupler is connected to the control terminal of the fourth switch. The switching path of the fourth switch is connected in series in the power supply circuit of the coil of the second relay.

6. The power module test circuit according to claim 1, characterized in that: The safety interlock circuit also includes: An overcurrent protection circuit is used to detect the current of the power module and, when the detected current exceeds the current threshold, controls the coil of the contactor to be de-energized.

7. The power module test circuit according to claim 6, characterized in that: The overcurrent protection circuit includes a current transformer and a thermal relay. The current transformer collects the output current of the power module, the thermal relay is connected in parallel across the current transformer, and the normally closed contact of the thermal relay is connected in series in the power supply circuit of the contactor coil.

8. The power module test circuit according to claim 1, characterized in that: The safety interlock circuit also includes: An emergency stop switch is connected in series in the power supply circuit of the contactor coil.

9. The power module test circuit according to claim 1, characterized in that: The power module test circuit also includes: A voltage regulator is used to change the voltage output by a power supply.

10. The power module test circuit according to any one of claims 1 to 9, characterized in that: The driving circuit of the power module includes: A signal generator that produces pulse signals; A drive signal conversion circuit converts the pulse signal generated by the signal generator into a pulse drive signal; The interface board sends the pulse drive signal generated by the drive signal conversion circuit to the drive board for driving the power module.

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