A method and circuit for full load testing of a high power h-bridge power cell

Abstract

The application relates to a kind of full-load test method and circuit of high-power H bridge power unit, which comprises: the output end of the H bridge power unit module to be tested is connected to a reactive load; the H bridge power unit module to be tested is driven by a PWM wave, the inverter output current and voltage of the H bridge power unit module to be tested are detected, so that the inverter output current of the H bridge power unit module to be tested is equal to the rated current value, the full-load current operation of the H bridge power unit module to be tested is realized; the inverter AC output voltage is compared with the rated voltage value, if the output voltage value is less than the rated value, the reactive load is reduced, and if the output voltage value is higher than the rated value, the reactive load is increased; when the H bridge power unit module to be tested reaches the voltage and current full-load operation state, it automatically enters the aging timing stage, and when the aging time reaches the set time, it automatically exits the full-load test. The application can perform full-load test on a single H bridge power unit module to be tested, has high test accuracy and low energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a method and circuit for full-load testing of a high-power H-bridge power unit. Background Technology

[0002] As the capacity of H-bridge cascaded devices (such as high-voltage SVG and high-voltage frequency converters) increases, full-load aging tests are required before the devices leave the factory. However, due to limitations in the capacity of the existing test platform, it is impossible to conduct high-voltage full-load tests. Increasing the capacity of the test platform by expanding the transformer capacity requires not only a large investment but also a long period of platform construction.

[0003] The most common full-load test method currently used is to use two sets of SVG devices of the same capacity to drive each other, one emitting inductive reactive power and the other emitting capacitive reactive power. The two sets of devices achieve power compensation, which consumes a lot of energy and cannot perform full-load tests on a single H-bridge power unit module under test. Summary of the Invention

[0004] This invention relates to a method and circuit for full-load testing of high-power H-bridge power units, which can at least solve some of the defects of the prior art.

[0005] The technical solution of this invention is implemented as follows: This invention discloses a full-load test method for a high-power H-bridge power unit, comprising the following steps:

[0006] The AC output terminal of the H-bridge power unit module under test is connected to a reactive load;

[0007] A PWM wave is generated to drive the H-bridge power unit module under test, while the inverter output current of the H-bridge power unit module under test is detected.

[0008] Calculate the amplitude of the inverter output current, compare the amplitude of the inverter output current with the rated current of the H-bridge power unit module under test, and adjust the control deviation to make the inverter output current of the H-bridge power unit module under test equal to the rated current value, thereby realizing the full-load current operation of the H-bridge power unit module under test.

[0009] When the H-bridge power unit module under test is running at full load current, the effective value of the inverter AC output voltage is detected and compared with the rated voltage value of the H-bridge power unit module under test. If the output voltage value is less than the rated value, the reactive load is reduced; if the output voltage value is higher than the rated value, the reactive load is increased. By adjusting the amount of reactive load, the aging test of the full load current and voltage of the H-bridge power unit module under test is finally achieved.

[0010] When the H-bridge power unit module under test reaches the state of full-load operation in terms of voltage and current, it automatically enters the aging timer stage. When the aging time reaches the set time, it automatically exits the full-load test and stops sending PWM waves to the H-bridge power unit module under test.

[0011] As one implementation method, DFT analysis is performed on the inverter output current of the H-bridge power unit module under test to calculate the amplitude of the inverter output current.

[0012] As one implementation method, an AC voltage is converted into the required DC voltage using a rectifier module, and a constant DC side voltage is obtained through a voltage stabilizing capacitor and output to the H-bridge power unit module under test.

[0013] As one implementation method, the inverter output current and voltage of the H-bridge power unit module under test are compared with the corresponding set values. When either the inverter output current or voltage of the H-bridge power unit module under test exceeds the corresponding set value, the full load test is automatically terminated.

[0014] As one implementation method, the control terminal of the H-bridge power unit module under test is connected to the control module, and the control module outputs a PWM wave to drive the H-bridge power unit module under test. The two DC input terminals of the H-bridge power unit module under test are connected to the DC positive and DC negative terminals respectively. One AC output terminal of the H-bridge power unit module under test is connected to one end of a reactive load through an inductor, and the other end of the reactive load is connected to the other AC output terminal of the H-bridge power unit module under test.

[0015] This invention discloses a full-load test circuit for a high-power H-bridge power unit, including an H-bridge power unit module under test and at least one reactive load. The control terminal of the H-bridge power unit module under test is connected to a control module. The two DC input terminals of the H-bridge power unit module under test are connected to the positive and negative DC terminals, respectively. One AC output terminal of the H-bridge power unit module under test is connected to one end of the reactive load via an inductor. The other end of the reactive load is connected to another AC output terminal of the H-bridge power unit module under test. When there are multiple reactive loads, the multiple reactive loads are connected in parallel.

[0016] As one implementation method, reactive load is capacitive load.

[0017] As one implementation method, the capacitive load is a capacitor.

[0018] As one embodiment, the high-power H-bridge power unit full-load test circuit of the present invention further includes a rectifier module. The input terminal of the rectifier module is connected to an AC power supply, and the two DC output terminals of the rectifier module are respectively connected to the two DC input terminals of the H-bridge power unit module under test. The rectifier module adopts a bridge rectifier circuit.

[0019] As one embodiment, the high-power H-bridge power unit full-load test circuit of the present invention further includes a voltage stabilizing capacitor. One end of the voltage stabilizing capacitor is connected to one DC input terminal of the H-bridge power unit module under test, and the other end of the voltage stabilizing capacitor is connected to the other DC input terminal of the H-bridge power unit module under test.

[0020] The present invention has at least the following beneficial effects: The above-described scheme allows for full-load testing of a single H-bridge power unit module under test, achieving full-load output with high testing accuracy. Furthermore, since the present invention uses a reactive load, energy consumption is low, saving electrical energy.

[0021] This invention provides AC overcurrent and AC overvoltage protection settings while adjusting the output of the H-bridge power unit module under test, preventing damage to the IGBT devices in the H-bridge power unit module under test due to overcurrent during the test process for H-bridge power unit modules of different capacities. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of a high-power H-bridge power unit full-load test circuit provided in one embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a high-power H-bridge power unit full-load test circuit provided for another embodiment of the present invention;

[0025] Figure 3 This is a flowchart of a high-power H-bridge power unit full-load test method provided in one embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] See Figure 1 and Figure 2This invention provides a full-load test circuit for a high-power H-bridge power unit, including an H-bridge power unit module under test and at least one reactive load. The control terminal of the H-bridge power unit module under test is connected to a control module. The two DC input terminals of the H-bridge power unit module under test are connected to the positive and negative DC terminals, respectively. One AC output terminal of the H-bridge power unit module under test is connected to one end of the reactive load via an inductor. The other end of the reactive load is connected to the other AC output terminal of the H-bridge power unit module under test. When there are multiple reactive loads, they are connected in parallel. The number of reactive loads is set according to actual needs; for example, different capacities of H-bridge power unit modules under test correspond to different numbers of reactive loads. The inductor can act as an energy buffer.

[0029] The control module of this invention can be an existing MCU module. The MCU module is connected to the bases of the four MOSFETs Q1, Q2, Q3, and Q4 of the H-bridge power unit module under test.

[0030] As one implementation method, reactive load is capacitive load.

[0031] As one implementation method, the capacitive load is a capacitor.

[0032] Preferably, the present invention includes a load device having several (two or more) plug-in interfaces for connecting reactive loads. The plug-in interfaces are spaced apart, and each plug-in interface includes a spaced-apart and independent first and second plug-in interfaces. The first plug-in interfaces are connected in series with wires, and the second plug-in interfaces are connected in series with wires. Two pins of each reactive load are plugged into the corresponding first and second plug-in interfaces, respectively, allowing multiple reactive loads to be connected in parallel. The load device has two external terminals. One external terminal is electrically connected to the first plug-in interface, and the other external terminal is electrically connected to the second plug-in interface. One external terminal is connected via an inductor to one AC output terminal of the H-bridge power unit module under test, and the other external terminal is connected to the other AC output terminal of the H-bridge power unit module under test. This invention, using the above scheme, allows for convenient manual connection or removal of reactive loads (capacitors).

[0033] Of course, this invention can also control the on / off state of the access switches via a control module to achieve automatic connection or removal of reactive loads. For example, if each reactive load is connected in series with an access switch, when a certain access switch is closed, the reactive load corresponding to that access switch is connected to the full-load test circuit. When a certain access switch is open, the reactive load corresponding to that access switch is removed from the full-load test circuit.

[0034] The access switch is electrically connected to the control module, which controls the switching on and off of the access switch. The access switch can be a relay or similar device.

[0035] As one embodiment, the high-power H-bridge power unit full-load test circuit of the present invention further includes a rectifier module. The input terminal of the rectifier module is connected to an AC power supply, and the two DC output terminals of the rectifier module are respectively connected to the two DC input terminals of the H-bridge power unit module under test.

[0036] As one implementation method, the rectifier module employs a bridge rectifier circuit. Of course, the rectifier module of the present invention is not limited to a bridge rectifier circuit; other existing types of rectifier circuits can also be used.

[0037] As one embodiment, the high-power H-bridge power unit full-load test circuit of the present invention further includes a voltage-stabilizing capacitor C1. One end of the voltage-stabilizing capacitor C1 is connected to one DC input terminal of the H-bridge power unit module under test, and the other end of the voltage-stabilizing capacitor C2 is connected to the other DC input terminal of the H-bridge power unit module under test. The present invention obtains a constant DC-side voltage through the function of the DC-side voltage-stabilizing capacitor.

[0038] Example 2

[0039] See Figures 1 to 3 This invention discloses a full-load test method for a high-power H-bridge power unit, comprising the following steps:

[0040] Connect the control terminal of the H-bridge power unit module under test to the control module. Connect the two DC input terminals of the H-bridge power unit module under test to the DC positive and DC negative terminals respectively. Connect one AC output terminal of the H-bridge power unit module under test to one end of the reactive load. Connect the other end of the reactive load to the other AC output terminal of the H-bridge power unit module under test.

[0041] The control module outputs a PWM wave to drive the H-bridge power unit module under test, and simultaneously detects the inverter output current of the H-bridge power unit module under test.

[0042] The amplitude of the inverter output current of the H-bridge power unit module under test is calculated. The amplitude of the inverter output current is compared with the rated current of the H-bridge power unit module under test. The control deviation is adjusted by the control module so that the inverter output current of the H-bridge power unit module under test is equal to the rated current value, thereby realizing the full-load current operation of the H-bridge power unit module under test.

[0043] When the H-bridge power unit module under test is running at full load current, the effective value of the inverter AC output voltage is detected and compared with the rated voltage value of the H-bridge power unit module under test. If the output voltage value is less than the rated value, the reactive load (load power) is reduced. If the output voltage value is higher than the rated value, the reactive load (load power) is increased. By adjusting the amount of reactive load, the aging test of the full load current and voltage of the H-bridge power unit module under test is finally achieved.

[0044] When the H-bridge power unit module under test reaches the state of full-load operation in terms of voltage and current, it automatically enters the aging timer stage. When the aging time reaches the set time, the control module will automatically exit the full-load test and stop sending PWM waves to the H-bridge power unit module under test.

[0045] As one implementation method, DFT analysis is performed on the inverter output current of the H-bridge power unit module under test to calculate the amplitude of the inverter output current.

[0046] As one implementation method, the AC voltage is converted into the required DC voltage using a rectifier module, and a constant DC side voltage is obtained through the voltage stabilizing capacitor C1, which is then output to the H-bridge power unit module under test.

[0047] As one implementation method, while the output of the H-bridge power unit module under test is adjusted, AC overcurrent and AC overvoltage protection settings are provided. The inverter output current and voltage of the H-bridge power unit module under test are compared with the corresponding set values. When either the inverter output current or voltage of the H-bridge power unit module under test exceeds the corresponding set value, the PWM wave sent to the H-bridge power unit module under test is stopped, and the control module will automatically exit the full load test to prevent overcurrent from causing damage to the IGBT devices in the power unit during the test.

[0048] While adjusting the output of the H-bridge power unit module under test, AC overcurrent and AC overvoltage protection is provided. Specifically, the inverter output current and voltage of the H-bridge power unit module under test are compared with the corresponding set values. When either the inverter output current or voltage of the H-bridge power unit module under test exceeds the corresponding set value, the adjustment is stopped to prevent overcurrent from causing damage to the IGBT devices in the power unit during the test.

[0049] The specific procedure for full-load testing of a high-power H-bridge power unit according to the present invention is as follows:

[0050] (1) The AC voltage is converted into the required DC voltage by using an uncontrolled rectifier (i.e., rectifier module), and a constant DC voltage is obtained through the action of the DC side voltage regulator capacitor.

[0051] (2) The H-bridge power unit module under test is driven by a PWM generated by sinusoidal pulse modulation. In this embodiment, the modulation wave is a 50Hz sine wave. The starting voltage is zero volts and the inverter output current is checked at the same time. The DC side voltage is introduced as a feedforward quantity during the modulation process to suppress the third harmonic component that is ultimately reflected in the inverter output current caused by the 2x DC side voltage component.

[0052] (3) Perform DFT analysis on the H-bridge inverter output current of the H-bridge power unit module under test, calculate the amplitude of the inverter output current, compare it with the rated current of the H-bridge power unit module under test, adjust the control deviation through the regulator, and finally make the inverter output current of the H-bridge power unit module under test equal to the rated current value, thereby realizing the full-load current operation of the H-bridge power unit module under test.

[0053] (4) When the H-bridge power unit module under test is running at full load current, the effective value of the inverter AC output voltage is compared with the rated voltage value of the H-bridge power unit module under test. If the output voltage value is less than the rated value, the reactive load (capacitor) needs to be reduced. If the output voltage value is higher than the rated value, the reactive load (capacitor) needs to be increased. By adjusting the amount of reactive load, the aging test of the full load current and voltage of the H-bridge power unit module under test can be finally achieved.

[0054] The entire testing process of this invention is an automatic control system that requires no human intervention. When the H-bridge power unit module under test reaches the state of full-load operation of voltage and current, it automatically enters the aging timer stage. When the aging time reaches the set time, the control module will automatically exit the full-load test and stop sending PWM waves to the H-bridge power unit module under test.

[0055] The low-voltage, high-power H-bridge power unit full-load test circuit used in this invention requires very little investment and can complete the platform construction in a very short time while meeting the full-load test requirements.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for full-load testing of a high-power H-bridge power unit, characterized in that, The AC output end of the to-be-tested H-bridge power unit module is connected with a reactive load, specifically, one AC output end of the to-be-tested H-bridge power unit module is connected with one end of the reactive load through an inductor, and the other end of the reactive load is connected with the other AC output end of the to-be-tested H-bridge power unit module; The AC voltage is converted into a required DC voltage through the rectifying module, and a constant DC side voltage is obtained through the voltage stabilizing capacitor, and is output to the to-be-tested H-bridge power unit module; The test method comprises the following steps: The PWM wave is formed by sinusoidal pulse modulation to drive the to-be-tested H-bridge power unit module, the starting voltage starts from zero volt and is inverted, and the inverter output current of the to-be-tested H-bridge power unit module is detected at the same time, the process of modulation introduces the DC side voltage as a feedforward quantity; The amplitude of the inverter output current is calculated, the amplitude of the inverter output current is compared with the rated current of the to-be-tested H-bridge power unit module, the control deviation is adjusted, and finally the inverter output current of the to-be-tested H-bridge power unit module is equal to the rated current value, so that the full load current operation of the to-be-tested H-bridge power unit module is realized; When the to-be-tested H-bridge power unit module is in full load current operation, the voltage effective value of the inverter AC output is detected and compared with the rated voltage value of the to-be-tested H-bridge power unit module, if the output voltage value is less than the rated value, the number of reactive loads is reduced, and if the output voltage value is higher than the rated value, the number of reactive loads is increased, and finally the full load current and voltage aging test of the to-be-tested H-bridge power unit module is realized by adjusting the number of reactive loads, when the reactive load is multiple, the multiple reactive loads are in parallel state, and the reactive load is a capacitive load; When the to-be-tested H-bridge power unit module reaches the state of voltage and current full load operation, it automatically enters the aging timing stage, and when the aging time reaches the set time, it automatically exits the full load test; The inverter output current and voltage of the to-be-tested H-bridge power unit module are compared with the corresponding set values respectively, when one of the inverter output current and voltage of the to-be-tested H-bridge power unit module exceeds the corresponding set value, the full load test is automatically exited.

2. The method of claim 1, wherein: The inverter output current of the to-be-tested H-bridge power unit module is analyzed by DFT, and the amplitude of the inverter output current is calculated.

3. The method of claim 1, wherein: The control end of the to-be-tested H-bridge power unit module is connected with the control module, the PWM wave is output by the control module to drive the to-be-tested H-bridge power unit module, and the two DC input ends of the to-be-tested H-bridge power unit module are connected with the DC positive pole and the DC negative pole respectively.

4. A high power H-bridge power cell full load test circuit, characterized by: The test device comprises a to-be-tested H-bridge power unit module and at least one reactive load, the control end of the to-be-tested H-bridge power unit module is connected with the control module, the two DC input ends of the to-be-tested H-bridge power unit module are connected with the DC positive pole and the DC negative pole respectively, one AC output end of the to-be-tested H-bridge power unit module is connected with one end of the reactive load through an inductor, and the other end of the reactive load is connected with the other AC output end of the to-be-tested H-bridge power unit module, when the reactive load is multiple, the multiple reactive loads are in parallel state; The rectifier module is connected with an alternating current power supply at an input end, and two direct current output ends of the rectifier module are connected with two direct current input ends of the H-bridge power unit module to be tested respectively. The voltage stabilizing capacitor is connected with one direct current input end of the H-bridge power unit module at one end, and connected with another direct current input end of the H-bridge power unit module at the other end. The reactive load is a capacitive load. The control module is used for executing the full-load test method of the high-power H-bridge power unit as claimed in any one of claims 1 to 3.

5. The full load test circuit for a high power H-bridge power cell of claim 4, wherein: The capacitive load is a capacitor.

6. The high power H-bridge power cell full load test circuit of claim 4, wherein: The rectifier module adopts a bridge rectifier circuit.

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