Device series connection type power module test circuit, method, apparatus, medium and program

Abstract

The invention provides a device series connection type power module test circuit, method, equipment, medium and program. The circuit comprises an H-type bridge circuit composed of four device series connection type power modules, a controller, a direct-current voltage source, a switched capacitor module circuit and an alternating-current reactor. The device series connection type power module is composed of a single main power device, a clamping diode, a dynamic voltage-sharing capacitor and the like. The controller is used for acquiring the output voltage of each tested device series connection type power module and sending a control signal to each tested device series connection type power module and a switch capacitor module circuit; and the switched capacitor module circuit is used for controlling the output of controllable direct-current voltage to the H-type bridge circuit. The test circuit has two test modes after being charged, including a load mode and a low-voltage ride-through mode, can simulate a real working condition to perform an equivalent test on the state of the device series connection type power module, and the test result has high accuracy.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of power electronics technology, and in particular to a device series power module test circuit, method, equipment, medium and program. Background Art

[0002] With the development of new energy, converters play an increasingly important role in new power systems. An important trend of converters is high voltage and high power, characterized by access to high-voltage power grids through module cascading or device series connection. In the main circuit of a device series converter, the converter bridge arm is composed of several single-power device modules in series. In order to ensure the dynamic voltage balancing effect during series connection, a voltage balancing circuit is generally designed inside each module to reduce the voltage difference between the single-power devices in series during operation, which is called a device series power module.

[0003] The device series power module has a different main circuit structure from the half-bridge module or full-bridge module used in the conventional cascade converter. It also needs to be tested after mass production to ensure that the functions and performance of each module meet the design requirements. The existing test circuit can only test the half-bridge module or full-bridge module used in the conventional cascade converter, but cannot test the device series power module. Summary of the invention

[0004] The embodiments of the present invention provide a device series power module test circuit, method, equipment, medium and program to solve the problem that the existing test circuit can only test the half-bridge module or full-bridge module used in the conventional cascade converter, but cannot test the device series power module.

[0005] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0006] In a first aspect, an embodiment of the present invention provides a test circuit for a device series power module, comprising: an H-bridge circuit consisting of four device series power modules to be tested, a controller, a DC voltage source, a switch capacitor module circuit, and an AC reactance;

[0007] The controller is coupled to each of the tested device series power modules and the switch capacitor module circuit respectively, and is used to obtain the output voltage of each of the tested device series power modules, and is used to send a control signal to each of the tested device series power modules and the switch capacitor module circuit; the tested device series power module is used to be turned on or off under the control of the control signal; the switch capacitor module circuit is used to control the voltage output to the H-type bridge circuit under the control of the control signal;

[0008] The DC side of the switch capacitor module circuit is coupled to the DC voltage source, the AC side of the switch capacitor module circuit is coupled to the DC side of the H-type bridge circuit, and the AC reactance is coupled to both ends of the AC side of the H-type bridge circuit.

[0009] Optionally, it also includes:

[0010] The soft start circuit is coupled to the positive terminal of the AC side of the switch capacitor module circuit and the positive terminal of the DC side of the H-type bridge circuit respectively.

[0011] In a second aspect, an embodiment of the present invention provides a method for testing a device series power module, based on the test circuit described in any one of the first aspects, the method comprising:

[0012] Complete charging of each of the tested device series-connected power modules;

[0013] The controller is operated to send a first test mode signal to the switch capacitor module circuit and each of the tested device series power modules, and the switch capacitor module circuit, under the control of the first test mode signal, controls the output of a voltage with a preset frequency and an adjustable duty cycle to the H-type bridge circuit; each of the tested device series power modules is turned on or off according to a first pulse mode under the control of the first test mode signal; or, the controller is operated to send a second test mode signal to the switch capacitor module circuit and each of the tested device series power modules, and the switch capacitor module circuit, under the control of the second test mode signal, controls the output of a first voltage to the H-type bridge circuit, wherein the first voltage is a voltage having an amplitude equal to that of the output voltage of a DC voltage source; each of the tested device series power modules is turned on or off according to a second pulse mode under the control of the second test mode signal;

[0014] Whether the device series power module under test is faulty is determined according to the waveform of the output voltage of each device series power module under test acquired by the controller.

[0015] Optionally, the expression of the control pulse when the switch capacitor module circuit generates the duty cycle adjustable voltage is as follows:

[0016]

[0017] Among them, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit, and the frequency is 100Hz; SC1 is the upper tube of the switch capacitor module circuit, SC2 is the lower tube of the switch capacitor module circuit, and the lower tube pulse T of the switch capacitor module circuit is SC2 is the upper tube pulse T SC1 Invert;

[0018] The expression of the first pulse mode is as follows:

[0019]

[0020] Among them, Ud H is the reference voltage of the device series power module under test; Tri2 is the triangular carrier of the device series power module under test; H1 to H4 represent four device series power modules under test respectively; T H1 To T H4 Corresponding control pulses H1 to H4 are shown.

[0021] Optionally, when the switch capacitor module circuit generates the first voltage, the expression of the control pulse is as follows:

[0022] T SC1 =1

[0023] T SC2 =0

[0024] Among them, TSC1 is the upper tube pulse, and TSC2 is the lower tube pulse;

[0025] The pulse expression of the second pulse mode is as follows:

[0026]

[0027] T H2 = not(T H1 )

[0028]

[0029] T H4 = not(T H3 )

[0030] Wherein, Tri3 is the triangular carrier of each of the tested device series type power modules, H1 to H4 represent four of the tested device series type power modules respectively; U refH1 is the reference voltage of H1, which is a sinusoidal modulation signal; U refH3 is the reference voltage of H3, which is a sinusoidal modulation signal; T H1 To T 44 Corresponding control pulses H1 to H4 are shown.

[0031] Optionally, the test circuit further includes: a soft start circuit, coupled to the positive terminal of the AC side of the switch capacitor module circuit and the positive terminal of the DC side of the H-type bridge circuit respectively;

[0032] Charging each of the tested device series power modules includes:

[0033] Using the slow start circuit to initially power on the switch capacitor module circuit and each of the tested device series power modules;

[0034] Control the DC voltage source to increase the output voltage at a preset boost rate until the switch capacitor module circuit reaches its own DC voltage rating, and complete the charging of each of the tested device series-type power modules; wherein, during the period when the DC voltage source increases the output voltage at the preset boost rate, operate the controller to send a controllable charging signal to the switch capacitor module circuit and each of the tested device series-type power modules, and the switch capacitor module circuit, under the control of the controllable charging signal, controls the output of a preset frequency duty cycle adjustable voltage to the H-type bridge circuit; each of the tested device series-type power modules, under the control of the controllable charging signal, is turned on or off according to the third pulse mode;

[0035] The expression of the control pulse when the switch capacitor module circuit generates the duty cycle adjustable voltage is as follows:

[0036]

[0037] Among them, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit, and the frequency is 100Hz; the lower tube pulse T of the switch capacitor module circuit SC2 is the upper tube pulse T SC1 Invert;

[0038] The pulse expression of the third pulse mode is as follows:

[0039]

[0040] Among them, Ud H is the reference voltage of the device series power module under test; Tri2 is the triangular carrier of the device series power module under test; H1 to H4 represent four device series power modules under test respectively; T H1 To T H4 Corresponding control pulses H1 to H4 are shown.

[0041] Optionally, determining whether the tested device series power module is faulty according to the waveform of the output voltage of each of the tested device series power modules acquired by the controller includes:

[0042] Query the database to obtain the waveform of the output voltage of the healthy device series power module under the working condition corresponding to the current test mode as a reference waveform;

[0043] Comparing the deviation between the reference waveform and the waveform of the output voltage of each of the tested device series power modules to obtain a comparison result;

[0044] If the comparison result indicates that the deviation is less than a preset deviation threshold, determining that the device series power module under test is healthy;

[0045] If the comparison result indicates that the deviation is greater than or equal to the preset deviation threshold, it is determined that the series power module of the device under test is faulty.

[0046] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps in the method for testing a device series power module as described in any one of the second aspects.

[0047] In a fourth aspect, an embodiment of the present invention provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps in the test method of a device series power module as described in any one of the second aspects are implemented.

[0048] In a fifth aspect, an embodiment of the present invention provides a computer program product, comprising computer instructions, which, when executed by a processor, implement the steps of the method for testing a device series power module as described in any one of the second aspects.

[0049] In the embodiment of the present invention, the test circuit includes: an H-bridge circuit, a controller, a DC voltage source, a switch capacitor module circuit, and an AC reactance. The test circuit of the embodiment of the present invention can test the device state of the device series power module, and can simulate the test of the device series power module under different working conditions, avoiding the problem of inaccurate test results under a single working condition, and the test results have high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0051] Figure 1a A circuit diagram of a test circuit for a device series-connected power module according to an embodiment of the present invention;

[0052] Figure 1b It is a circuit diagram of a device series type power module;

[0053] Figure 2 It is a schematic flow chart of a method for testing a device series-connected power module according to an embodiment of the present invention;

[0054] Figure 3 It is a pulse waveform diagram of the switch capacitor module circuit under power load condition;

[0055] Figure 4 It is a schematic diagram of the pulse waveform of each device series power module under the power load condition;

[0056] Figure 5 It is a schematic diagram of the capacitor voltage of the series-connected power module of each device under test and the voltage waveform of the test circuit under power load conditions;

[0057] Figure 6 It is a schematic diagram of the current waveform of each device series power module and the test circuit under power load conditions;

[0058] Figure 7 It is a waveform diagram of the switched capacitor module circuit under low voltage ride-through conditions;

[0059] Figure 8 It is a schematic diagram of the pulse waveform of each tested device series power module under low voltage ride-through conditions;

[0060] Fig. 9 It is a schematic diagram of the capacitor voltage of the series-connected power module of each device under test and the voltage of the test circuit under the low voltage ride-through condition;

[0061] Fig.10 It is a schematic diagram of the current waveform of each device in series and the test circuit under the low voltage ride-through condition;

[0062] Fig.11 A schematic diagram of the pulse waveform of the switched capacitor module circuit during controllable charging;

[0063] Fig.12 It is a schematic diagram of the pulse waveform of each device series power module under test during the controllable charging period;

[0064] Fig.13 A schematic diagram of the capacitor voltage of each device series power module under test and the capacitor voltage of the test circuit during the controllable charging period;

[0065] Fig.14 This is a schematic diagram of the measured waveform when the device series power module test platform is loaded with a large current;

[0066] Fig.15 The figure is a principle block diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0068] The terms "first", "second", etc. of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of one type, and the number of objects is not limited, for example, the first object can be one or more. In addition, "or" in the present application represents at least one of the connected objects. For example, "A or B" covers three schemes, namely, Scheme 1: including A but not including B; Scheme 2: including B but not including A; Scheme 3: including both A and B. The character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0069] In the technical solution of the present disclosure, words such as “connect”, “couple” or “connected” are not limited to physical or mechanical connections, but may include electrical connections.

[0070] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0071] The embodiment of the present invention provides a test circuit for a device series power module.

[0072] See also Figure 1a As shown, the test circuit includes: an H-bridge circuit 100, a controller 200, a DC voltage source 300, a switch capacitor module circuit 400, and an AC reactance 500;

[0073] The H-bridge circuit 100 is composed of four tested device series power modules 101, for example, see Figure 1b As shown, the device series power module consists of a power main device and a voltage balancing branch in parallel, where the power main device is a fully controlled device with an anti-parallel diode, and the voltage balancing branch consists of a clamping diode, a voltage balancing resistor, and a voltage balancing capacitor. When used, the power main device of the module is connected in series in the bridge arm to assume the opening and closing functions of the circuit, and the voltage balancing branch is used to ensure that the static and dynamic withstand voltages of the power module in the series circuit are consistent with those of other modules in the series circuit.

[0074] The main circuit parameters of the device series power module are as follows: the fully controlled device is 6500V / 4000AIGCT, the support capacitor is 90uF, and the voltage-sharing resistor is 24.6kΩ; the main parameters of the switching capacitor module are: 4500V / 3000A IGBT, the DC capacitor is 4.5mF. In order to reduce the fluctuation on the DC side of the switching capacitor module, a capacitor of the same capacity of 4.5mF is connected in parallel, which is equivalent to a DC side capacitor of 9mF.

[0075] The controller 200 is coupled to each tested device series power module 101 and the switch capacitor module circuit 400, respectively, and is used to obtain the output voltage of each tested device series power module 101, and is used to send a control signal to each tested device series power module 101 and the switch capacitor module circuit 400; the tested device series power module 101 is used to turn on or off under the control of the control signal; the switch capacitor module circuit 400 is used to control the voltage output to the H-type bridge circuit 100 under the control of the control signal;

[0076] The DC side of the switched capacitor module circuit 400 (ie, SC) is coupled to the DC voltage source 300, the AC side of the switched capacitor module circuit 400 is coupled to the DC side of the H-type bridge circuit 100, and the AC reactor 500 is connected to both ends of the AC side of the H-type bridge circuit. Figure 1a As shown, four tested device series power modules 101 are connected in series in pairs to form two series branches, the two series branches are coupled in parallel, and the two parallel coupling ends between the two series branches respectively form two DC connection terminals 102; on each series branch, the series coupling end between the two tested device series power modules 101 forms an AC connection terminal 103. The switch capacitor module circuit 400 includes an AC side positive terminal 401, an AC side negative terminal 402, a first DC side connection terminal 403, and a second DC side connection terminal 404; the AC side positive terminal 401 is coupled to a DC connection terminal 102 of the two DC connection terminals 102, and the AC side negative terminal 402 is coupled to the other DC connection terminal 102 of the two DC connection terminals 102; the first DC side connection terminal 403 is coupled to the positive terminal of the DC voltage source 300, and the second DC side connection terminal 404 is coupled to the negative terminal of the DC voltage source 300; the switch capacitor module circuit 400 is used to control the voltage output to the H-type bridge circuit 100 under the control of a control signal; the first end of the AC reactance 500 is coupled to one of the two AC connection terminals 103, and the second end of the AC reactance 500 is coupled to the other AC connection terminal 103 of the two AC connection terminals 103.

[0077] In the embodiment of the present invention, the voltage source is a DC voltage source 300, which supplies energy to the H-type bridge circuit 100 via a switch capacitor module circuit 400. The voltage output to the H-type bridge circuit 100 can be regulated by controlling the switch capacitor module circuit 400.

[0078] In actual applications, the controller 200 can send a control signal to each tested device series power module 101 and the switch capacitor module circuit 400. The switch capacitor module circuit 400 controls the voltage output to the H-bridge circuit 100 under the control of the control signal. Each tested device series power module 101 is turned on or off according to various pulse modes under the control of the control signal, thereby simulating the operation of each tested device series power module 101 under various test conditions. The output voltage of each tested device series power module 101 under the test condition is obtained through the controller 200, and whether the tested device series power module 101 is faulty is determined according to the waveform of the output voltage.

[0079] In some embodiments of the present invention, the test conditions may include: the conditions when the device series power module 101 is in normal operation, i.e., the power load conditions. The test conditions may also include: the conditions when the device series power module 101 is in low voltage ride-through of the power grid, i.e., the low voltage ride-through conditions.

[0080] In some embodiments of the present invention, optionally, see Figure 1a As shown, the test circuit also includes:

[0081] The soft start circuit 600 is coupled to the positive terminal of the AC side of the switch capacitor module circuit 400 and the positive terminal of the DC side of the H-type bridge circuit. Figure 1a As shown, the soft start circuit 600 is coupled to the AC side positive terminal 401 and one of the two DC connection terminals 102 , respectively.

[0082] Specifically, see the embodiments of the present invention. Figure 1a As shown, the slow start circuit 600 includes a slow start resistor R1 and a switch K1 coupled in parallel with the slow start resistor R1. One parallel coupling end of the slow start resistor R1 and the switch K1 is coupled to the AC side positive terminal 401, and the other parallel coupling end is coupled to a DC connection terminal 102 of the two DC connection terminals 102.

[0083] In practical applications, a slow start circuit is used to initially power on the switch capacitor module circuit and each device series power module under test. Specifically, in the initial power-on stage, the DC voltage source 300 is started, and the switch K1 is turned off to put the slow start resistor R1 into the loop, and the DC voltage source 300 is adjusted until the DC voltage rises to the power start threshold voltage of the switch capacitor module circuit 400 and each device series power module 101 under test, and each device series power module 101 under test starts to work, completing the initial power-on.

[0084] The slow-start resistor can effectively reduce the instantaneous current during startup, ensuring that the DC voltage source 300 will not impact the switch capacitor module circuit and the series-connected power modules of each device under test during startup, thereby avoiding the test circuit itself from causing failures to the series-connected power modules of each device under test.

[0085] The embodiment of the present invention provides a method for testing a device series power module. Based on any one of the test circuits in the embodiments of the present invention, see Figure 2 As shown, the method includes:

[0086] Step S1: Complete charging of each device series power module under test;

[0087] Step S2: the operation controller sends a first test mode signal to the switch capacitor module circuit and each device series power module under test, and the switch capacitor module circuit, under the control of the first test mode signal, controls the output of a voltage with a preset frequency and an adjustable duty cycle to the H-type bridge circuit; each device series power module under the control of the first test mode signal is turned on or off according to the first pulse mode; or, the operation controller sends a second test mode signal to the switch capacitor module circuit, and the switch capacitor module circuit, under the control of the second test mode signal, controls the output of a first voltage to the H-type bridge circuit, and the first voltage is a voltage equal to the output voltage amplitude of the DC voltage source; each device series power module under the control of the second test mode signal is turned on or off according to the second pulse mode;

[0088] Step S3: determining whether the tested device series-connected power module is faulty according to the waveform of the output voltage of each tested device series-connected power module acquired by the controller.

[0089] The following combination Figure 1aThe test circuit shown in the example is used to illustrate that the controller 200 can send a control signal to each tested device series power module 101 and the switch capacitor module circuit 400. The switch capacitor module circuit 400 controls the voltage output to the H-bridge circuit 100 under the control of the control signal, and each tested device series power module 101 is turned on or off according to the first pulse mode under the control of the control signal, thereby simulating the operation of each tested device series power module 101 under various test conditions. The output voltage of each tested device series power module 101 under the test condition is obtained through the controller 200, and whether the tested device series power module 101 is faulty is determined according to the waveform of the output voltage.

[0090] In some embodiments of the present invention, optionally, the first test mode signal may indicate the simulation of the series-connected power modules of each tested device under power-load conditions; the second test mode signal indicates the simulation of the series-connected power modules of each tested device under low voltage ride-through conditions.

[0091] Specifically, under the control of the first test mode signal, the switch capacitor module circuit controls the output of a voltage with a preset frequency and an adjustable duty cycle to the H-bridge circuit; and, under the control of the first test mode signal, each tested device series power module 101 is turned on or off according to the first pulse mode, thereby simulating the operation of each tested device series power module 101 under power load conditions. According to the waveform of the output voltage of each tested device series power module obtained by the controller, it is determined whether the tested device series power module is faulty.

[0092] Specifically, the switching capacitor module circuit, under the control of the second test mode signal, controls the output of a first voltage to the H-bridge circuit, wherein the first voltage is a voltage equal to the output voltage amplitude of the DC voltage source; and, each tested device series power module 101 is turned on or off according to the second pulse mode under the control of the second test mode signal, thereby simulating the operation of each tested device series power module 101 under low voltage ride-through conditions, and determining whether the tested device series power module is faulty based on the output voltage waveform of each tested device series power module obtained by the controller.

[0093] In the embodiment of the present invention, through steps S1 to S3, the embodiment of the present invention can test the device state of the series power module. In addition, the embodiment of the present invention can simulate the test of the tested device series power module under different working conditions, and determine whether the tested device series power module is faulty according to the waveform of the output voltage of each tested device series power module under different working conditions, thereby avoiding the problem of inaccurate test results under a single working condition, so that the test results have high accuracy.

[0094] In some embodiments of the present invention, optionally, the preset frequency includes 50 Hz. The above frequency is the power frequency, and the duty cycle adjustable voltage of 50 Hz is controlled to be output to the H-bridge circuit, so that the simulated power load condition is closer to the actual power load condition, ensuring a high-accuracy test result.

[0095] In some embodiments of the present invention, optionally,

[0096] The expression of the control pulse when the switch capacitor module circuit 400 generates a duty cycle adjustable voltage is as follows:

[0097]

[0098] Under power load conditions, the pulse of the switched capacitor module circuit 400 is as follows: Figure 3 As shown, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit, and the frequency is 100 Hz; SC1 is the upper tube of the switch capacitor module circuit 400, SC2 is the lower tube of the switch capacitor module circuit 400, and the lower tube pulse T of the switch capacitor module circuit SC2 is the upper tube pulse T SC1 Invert.

[0099] Correspondingly, the pulse expression of the first pulse mode is as follows:

[0100]

[0101] Among them, Ud H is the reference voltage of the device series power module 101 under test, indicating the duty cycle, which can be a constant; Tri2 is the triangular carrier of the device series power module 101 under test; H1 to H4 respectively represent four device series power modules under test, H1 and H2 constitute one series branch, and H3 and H4 constitute another series branch; T H1 To T H4 Corresponding control pulses H1 to H4 are shown.

[0102] Under the power load condition, the pulses of the series-connected power modules 101 in the H-bridge circuit are as follows: Figure 4 As shown, where Ud H is the reference voltage of the device series power module, which indicates the duty cycle and can be a constant. Tri2 is the triangular carrier of the series power module, with a frequency of 50Hz. When the reference voltage is greater than the carrier, the pulse T of the upper left power module H1 H1 and the pulse T of the lower right power module H4 H4 Turn on, pulse T of lower left power module H2 H2 and the pulse T of the lower right power module H3 H3In addition, the carrier Tri1 of the switched capacitor module and the carrier Tri2 of each H-bridge module are in phase, and the frequency of Tri1 is twice that of Tri2.

[0103] Under the power load condition, the voltage waveform of the capacitor voltage of each device series power module 101 under test in the H-bridge circuit and the voltage waveform of the test circuit are as follows: Figure 5 As shown, the output voltage U SCout The voltage UcapH1 to UcapH4 of the capacitors of the four tested devices in series in the power module 101 remain constant. The output voltage UcapH1 of the H-type bridge circuit under the power load condition is Hout It is three-level.

[0104] Under power load conditions, the current waveforms of the series power modules of the tested devices and the current waveforms of the test circuit are as follows: Figure 6 As shown, the AC reactance is 500 and the current I L1 is a 50Hz current, the main component of which is the fundamental wave. The current I H1 ~I H4 The half-wave is turned on and the half-wave is turned off. The half-wave when turned on is related to the reactance current I L1 The bridge arm current I SC1 The frequency is 100Hz.

[0105] In the embodiment of the present invention, under the power load condition, the DC voltage source is maintained at the operating voltage (e.g., 2500V), the switch capacitor module circuit 400 operates at an adjustable duty cycle voltage of 100Hz, and the H-type bridge circuit operates in a mode of alternating conduction of the tubes (i.e., the first pulse mode), that is, the upper left power module H1 and the lower right power module H4 are turned on and off at the same time to output a positive half-wave, and the lower left power module H2 and the upper right power module H3 are turned on and off at the same time to output a negative half-wave, so the AC output voltage of the H-bridge circuit is a square wave three-level, and the AC output end is the potential difference between the midpoint of the H1 / H2 module and the midpoint of the H3 / H4 module, that is, the voltage across the AC reactance 500. The time for the alternating conduction switching of H1 / H4 and H2 / H3 is the moment when the switch capacitor module is turned off, and the device series power module operates in a zero voltage commutation mode. The current flows through the series-connected power modules 101 and the AC reactor 500, and the current size can be adjusted by the duty cycle of the pulse of the switch capacitor module circuit 400. Since the tubes are alternately turned on, the current in each of the series-connected power modules 101 is a half-wave current, which realizes the performance verification of each of the series-connected power modules 101, which is consistent with the working condition of the whole machine when it is in steady state operation.

[0106] Under power load conditions, performance verification includes the operating capability under rated voltage and rated current. The rated voltage refers to the voltage on the DC side capacitor inside the device series power module 101 under test, which is determined by the DC side voltage source amplitude level of the entire test circuit. The rated current refers to the maximum current passing through the device series power module 101 under test, which is adjusted by the duty cycle of the switch capacitor module circuit 400 pulse. The current peak value is equal to the current I of the AC reactance 500. L1 The peak values ​​are the same.

[0107] In some embodiments of the present invention, optionally,

[0108] Under the low voltage ride-through condition, the upper tube of the switch capacitor module circuit 400 is always turned on, and the lower tube of the switch capacitor module circuit 400 is always turned off. Figure 7 As shown, the expression of the control pulse when the switch capacitor module circuit 400 generates the first voltage is as follows:

[0109] T SC1 =1

[0110] T SC2 =0

[0111] Among them, SC1 is the upper tube of the switch capacitor module circuit 400, SC2 is the lower tube of the switch capacitor module circuit 400, TSC1 is the upper tube pulse, and TSC2 is the lower tube pulse.

[0112] Correspondingly, the pulse expression of the second pulse mode is as follows:

[0113]

[0114] T H2 = not(T H1 )

[0115]

[0116] T H4 = not(T H3 )

[0117] Wherein, T1 to T4 correspond to the pulse voltages of H1 to H4; Tri3 is the triangular carrier of each tested device series power module, H1 to H4 respectively represent 4 of the tested device series power modules, H1 and H2 constitute one of the series branches, and H3 and H4 constitute another of the series branches; U refH1 and U refH3 They are the reference voltages of power module H1 and power module H3 respectively, which are sinusoidal modulation signals and are expressed as follows:

[0118] Uref H1 =M*sin(ωt)

[0119] Uref H3 =-M*sin(ωt)

[0120] Among them, U refH1 and U refH3 The modulation signals of the two are opposite, M is the modulation ratio of the reference voltage, ω represents the angular frequency, t represents the time, and the product of ω and t represents the phase of the sinusoidal modulation signal.

[0121] Under the low voltage ride-through condition, the pulse of each device in the H-bridge circuit is connected in series with the power module 101. Figure 8 As shown, where U refH1 is the reference voltage of power module H1, which is a sine wave with a frequency of 50Hz and a carrier frequency of 1000Hz; U refH3 is the reference voltage of power module H3. When the reference voltage is greater than the carrier, the pulse of the corresponding power module is turned on, and the pulse T of the lower left power module H2 H2 The pulse T of the upper left power module H1 H1 Inverted, pulse T of the lower right power module H4 H4 With the upper right power module H3 pulse T H3 Invert.

[0122] Under the low voltage ride-through condition, the voltage of each tested device series power module 101 is as follows: Fig. 9 As shown, the output voltage U of the switched capacitor module circuit 400 SCout is a fluctuating DC voltage; the capacitor voltages UcapH1 to UcapH4 of the four tested device series power modules 101 remain constant; the output voltage UcapH1 of the H-type bridge circuit under the low voltage ride-through condition is Hout It is a three-level PWM waveform.

[0123] Under the low voltage ride-through condition, the current waveforms of the series-connected power modules 101 and the test circuit of each device under test are as follows: Fig.10 As shown, the AC reactance is 500 and the current I L is a 50Hz current, the main component of which is the fundamental wave with a PWM high-frequency component; the current I H1 ~I H4 is a PWM waveform, the fundamental frequency is 50 Hz; the bridge arm current I SC1 It is a PWM waveform with a frequency of 100Hz.

[0124] In some embodiments of the present invention, optionally,

[0125] The test circuit further includes: a soft start circuit 600, which is coupled to the positive terminal of the AC side of the switch capacitor module circuit 400 and the positive terminal of the DC side of the H-bridge circuit 100. Figure 1a As shown, the soft start circuit 600 is coupled to the AC side positive terminal 401 and one of the two DC connection terminals 102 , respectively.

[0126] Complete charging of the series-connected power modules of each device under test, including:

[0127] Step a: using the slow start circuit to initially power on the switch capacitor module circuit and each of the tested device series power modules;

[0128] Step b: Control the DC voltage source to increase the output voltage at a preset boost rate until the switch capacitor module circuit reaches its own DC voltage rating, and complete the charging of each of the tested device series-type power modules; wherein, during the period when the DC voltage source increases the output voltage at the preset boost rate, the controller is operated to send a controllable charging signal to the switch capacitor module circuit and each of the tested device series-type power modules, and the switch capacitor module circuit, under the control of the controllable charging signal, controls the output of a preset frequency duty cycle adjustable voltage to the H-type bridge circuit; each of the tested device series-type power modules, under the control of the controllable charging signal, is turned on or off according to the third pulse mode;

[0129] The expression of the control pulse when the switched capacitor module circuit generates a duty cycle adjustable voltage is as follows:

[0130]

[0131] During the controllable charging period, the pulse waveform of the switched capacitor module circuit 400 is as follows: Fig.11 As shown, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit 400, and the frequency is 100Hz; SC1 is the upper tube of the switch capacitor module circuit 400, SC2 is the lower tube of the switch capacitor module circuit 400, and the lower tube pulse T of the switch capacitor module circuit SC2 is the upper tube pulse T SC1 Invert.

[0132] Correspondingly, the pulse expression of the third pulse mode is as follows:

[0133]

[0134] During the controllable charging period, the pulse waveform of each device series power module 101 under test in the H-bridge circuit is as follows: Fig.12 As shown, UdH is the reference voltage of the device series power module 101 under test, which indicates the duty cycle and can be a constant; Tri2 is the triangular carrier of the device series power module 101 under test, with a frequency of 50Hz; Tri1 and Tri2 are in phase, and the frequency of Tri1 is twice that of Tri2. H When the pulse T of the upper left power module H1 is greater than the carrier Tri2, H1 and the pulse T of the upper right power module H3 H3 Turn on, pulse T of lower left power module H2 H2 and the pulse T of the lower right power module H4 H4 Shut down.

[0135] During the controllable charging period, the capacitor voltage of each tested device series power module 101 and the capacitor voltage of the test circuit are as follows: Fig.13 As shown, the output voltage U of the switched capacitor module circuit 400 SCout The peak value continues to rise, and the capacitor voltages UcapH1 to UcapH4 of the four tested device series power modules 101 rise synchronously. During the controllable charging period, the upper bridge arm of the H-type bridge circuit has the same voltage, so the output voltage U Hout is zero.

[0136] In some embodiments of the present invention, optionally, determining whether the device series power module under test is faulty according to the waveform of the output voltage of each device series power module under test acquired by the controller includes:

[0137] Step c: querying the database to obtain the waveform of the output voltage of the healthy device series power module under the working condition corresponding to the current test mode as a reference waveform;

[0138] Step d: comparing the deviation between the reference waveform and the waveform of the output voltage of each tested device series power module to obtain a comparison result;

[0139] Step e: if the comparison result indicates that the deviation is less than a preset deviation threshold, determining that the device series power module under test is healthy;

[0140] Step f: If the comparison result indicates that the deviation is greater than or equal to a preset deviation threshold, it is determined that the series power module of the device under test is faulty.

[0141] In an embodiment of the present invention, the database includes a cloud database. The waveform of the output voltage of the healthy device series power module under various working conditions is stored in the database. When executing step c, by querying the database, the waveform of the output voltage of the healthy device series power module under the working condition corresponding to the current test mode can be obtained as a reference waveform.

[0142] In the embodiment of the present invention, the deviation threshold can be determined by the user according to the specific test standard. For example, if the test standard is high, a low deviation threshold is used; if the test standard is low, a high deviation threshold is used. The above deviation thresholds cannot be exhaustive. It should be noted that the inability to be exhaustive should not be considered unclear.

[0143] In the embodiment of the present invention, a device series power module test platform is constructed to achieve high current load, and the measured waveform is as follows: Fig.14 As shown, high-power current loading under rated DC voltage is achieved. Among them, IC is the upper tube current of the switch capacitor module, the reactance current is the load current, the main frequency is 50Hz fundamental wave, Vge and Vce are the gate voltage and collector voltage of the switch capacitor module, which are consistent with the pulse, and the capacitor voltage is a DC voltage with double frequency fluctuation.

[0144] The embodiment of the present invention provides an electronic device 150, see Fig.15 As shown, Fig.15 This is a principle block diagram of an electronic device 150 according to an embodiment of the present invention, including a processor 151, a memory 152, and a program or instruction stored in the memory 152 and executable on the processor 151. When the program or instruction is executed by the processor, the steps in the test method of a series-connected power module of any device of the present invention are implemented.

[0145] An embodiment of the present invention provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of an embodiment of a method for testing a device series power module as described above is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0146] The readable storage medium is, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc. In some examples, the readable storage medium may be a non-transitory readable storage medium.

[0147] An embodiment of the present invention also provides a computer program product, including computer instructions. When the computer instructions are executed by a processor, the various processes of the test method embodiment of any of the above-mentioned device series power modules are implemented, and the same technical effect can be achieved. To avoid repetition, they are not repeated here.

[0148] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A test circuit for a device series power module, characterized in that: An H-bridge circuit consisting of four device-in-series power modules under test, a controller, a DC voltage source, a switched capacitor module circuit, and an AC reactance; The controller is coupled to each of the tested device series power modules and the switch capacitor module circuit respectively, and is used to obtain the output voltage of each of the tested device series power modules, and is used to send a control signal to each of the tested device series power modules and the switch capacitor module circuit; the tested device series power module is used to be turned on or off under the control of the control signal; the switch capacitor module circuit is used to control the voltage output to the H-type bridge circuit under the control of the control signal; The DC side of the switch capacitor module circuit is coupled to the DC voltage source, the AC side of the switch capacitor module circuit is coupled to the DC side of the H-type bridge circuit, and the AC reactance is coupled to both ends of the AC side of the H-type bridge circuit.

2. The device series power module test circuit according to claim 1, characterized in that: Also includes: The soft start circuit is coupled to the positive terminal of the AC side of the switch capacitor module circuit and the positive terminal of the DC side of the H-type bridge circuit respectively.

3. A method for testing a device series power module, based on the test circuit described in any one of claims 1 to 2, characterized in that: The method comprises: Complete charging of each of the tested device series-connected power modules; The controller is operated to send a first test mode signal to the switch capacitor module circuit and each of the tested device series power modules, and the switch capacitor module circuit, under the control of the first test mode signal, controls the output of a voltage with a preset frequency and an adjustable duty cycle to the H-type bridge circuit; each of the tested device series power modules is turned on or off according to a first pulse mode under the control of the first test mode signal; or, the controller is operated to send a second test mode signal to the switch capacitor module circuit and each of the tested device series power modules, and the switch capacitor module circuit, under the control of the second test mode signal, controls the output of a first voltage to the H-type bridge circuit, wherein the first voltage is a voltage having an amplitude equal to that of the output voltage of a DC voltage source; each of the tested device series power modules is turned on or off according to a second pulse mode under the control of the second test mode signal; Whether the device series power module under test is faulty is determined according to the waveform of the output voltage of each device series power module under test acquired by the controller.

4. The method for testing a device series power module according to claim 3, characterized in that: The control pulse expression when the switch capacitor module circuit generates the duty cycle adjustable voltage is as follows: Among them, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit, and the frequency is 100Hz; SC1 is the upper tube of the switch capacitor module circuit, SC2 is the lower tube of the switch capacitor module circuit, and the lower tube pulse T of the switch capacitor module circuit is SC2 is the upper tube pulse T SC1 Invert; The pulse expression of the first pulse mode is as follows: Among them, Ud H is the reference voltage of the device series power module under test; Tri2 is the triangular carrier of the device series power module under test; H1 to H4 represent four device series power modules under test respectively, T H1 To T H4 Corresponding control pulse signals H1 to H4.

5. The method for testing a device series power module according to claim 3, characterized in that: When the switch capacitor module circuit generates the first voltage, the control pulse expression is as follows: T SC1 ＝1 T SC2 ＝0 Among them, SC1 is the upper tube of the switch capacitor module circuit, SC2 is the lower tube of the switch capacitor module circuit, T SC1 is the upper tube pulse, T SC2 is the lower tube pulse; The pulse expression of the second pulse mode is as follows: T H2 =not(T H1 ) T H4 =not(T H3 ) Wherein, Tri3 is the triangular carrier of each of the tested device series type power modules, H1 to H4 represent four of the tested device series type power modules respectively; U refH1 is the reference voltage of H1, which is a sinusoidal modulation signal; U refH3 is the reference voltage of H3, which is a sinusoidal modulation signal; T H1 To T H4 Corresponding control pulses H1 to H4 are shown.

6. The method for testing a device series power module according to claim 3, characterized in that: The test circuit further includes: a soft start circuit, coupled to the positive terminal of the AC side of the switch capacitor module circuit and the positive terminal of the DC side of the H-type bridge circuit respectively; Charging each of the tested device series power modules includes: Using the slow start circuit to initially power on the switch capacitor module circuit and each of the tested device series power modules; Control the DC voltage source to increase the output voltage at a preset boost rate until the switch capacitor module circuit reaches its own DC voltage rating, and complete the charging of each of the tested device series-type power modules; wherein, during the period when the DC voltage source increases the output voltage at the preset boost rate, operate the controller to send a controllable charging signal to the switch capacitor module circuit and each of the tested device series-type power modules, and the switch capacitor module circuit, under the control of the controllable charging signal, controls the output of a preset frequency duty cycle adjustable voltage to the H-type bridge circuit; each of the tested device series-type power modules, under the control of the controllable charging signal, is turned on or off according to the third pulse mode; The control pulse expression when the switch capacitor module circuit generates the duty cycle adjustable voltage is as follows: Among them, Udsc is the duty cycle constant of the switch capacitor module circuit, Tri1 is the triangular carrier of the switch capacitor module circuit, and the frequency is 100Hz; SC1 is the upper tube of the switch capacitor module circuit, SC2 is the lower tube of the switch capacitor module circuit, and the lower tube pulse T of the switch capacitor module circuit is SC2 is the upper tube pulse T SC1 Invert; The pulse expression of the third pulse mode is as follows: Among them, Ud H is the reference voltage of the device series power module under test; Tri2 is the triangular carrier of the device series power module under test; H1 to H4 represent four device series power modules under test respectively, H1 and H2 constitute one series branch, and H3 and H4 constitute another series branch; T H1 To T H4 Corresponding control pulses H1 to H4 are shown.

7. The method for testing a device series power module according to claim 3, characterized in that: Determining whether the tested device series type power module is faulty according to the waveform of the output voltage of each tested device series type power module acquired by the controller includes: Query the database to obtain the waveform of the output voltage of the healthy series power module under the working condition corresponding to the current test mode as a reference waveform; Comparing the deviation between the reference waveform and the waveform of the output voltage of each of the tested device series power modules to obtain a comparison result; If the comparison result indicates that the deviation is less than a preset deviation threshold, determining that the device series power module under test is healthy; If the comparison result indicates that the deviation is greater than or equal to the preset deviation threshold, it is determined that the series power module of the device under test is faulty.

8. An electronic device, characterized in that: The method comprises a processor, a memory and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps in the method for testing a device series-connected power module as described in any one of claims 3 to 7.

9. A readable storage medium, characterized in that: The readable storage medium stores a program or an instruction, and when the program or the instruction is executed by the processor, the steps in the method for testing a device series-connected power module according to any one of claims 3 to 7 are implemented.

10. A computer program product, characterized in that The method comprises computer instructions, which, when executed by a processor, implement the steps of the method for testing a device series-connected power module according to any one of claims 3 to 7.

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