Method for controlling first wave peak value of high-capacity energy storage type test power supply

Abstract

The invention discloses a method for controlling a head wave peak value of a high-capacity energy storage type test power supply, which comprises the following steps of: applying a standard sinusoidal pulse width modulation (SPWM) pulse signal to each sub-power unit of a power unit, and outputting a test voltage after the output voltages of the sub-units are cascaded and superposed; collecting test waveforms of a first preset number of pulse signals, judging whether the peak value exceeds a preset threshold value or not, and continuing if the peak value does not exceed the preset threshold value; determining an adjustment proportion based on the peak difference, and calculating a DC component adjustment value in combination with a standard SPWM pulse signal amplitude; the number is segmented according to the time slices, and the direct-current component is gradually decreased to the last time slice of the last pulse signal of the first preset number to be 0 one time slice by one time slice; superposing the progressively decreased direct current component to the corresponding pulse signal to obtain a new SPWM pulse signal; and providing the first wave peak value to the sub-power unit to enable the first wave peak value to exceed a threshold value. According to the invention, the first wave peak value of the output test voltage is effectively improved to a preset threshold value, and the instantaneous peak tolerance test requirements of equipment such as a transformer and switch equipment are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power testing, in particular to a method for controlling the first-wave peak value of a large-capacity energy storage type test power supply. BACKGROUND

[0002] The existing large-capacity energy storage type test power supply at least includes a contactor, a charging unit, a step-up transformer, a super capacitor unit and a power unit. When storing energy, the large-capacity energy storage type test power supply makes a three-phase power supply supply power to the charging unit through the contactor. The output of the charging unit is connected to the step-up transformer. The voltage after the step-up of the transformer is charged to the super capacitor unit through the rectifier unit of the power unit. When testing, the electrical energy stored in the super capacitor unit is converted by the inverter unit of the power unit, and then a test voltage is output for testing the device under test, such as a transformer, a low-voltage switch, etc. The test performed is, for example, a transformer burst short-circuit test, a switch device current withstand test, etc. Since the short-time and peak current withstand test is completed by relying on the energy storage of the super capacitor unit, it will not cause any impact on the power supply side of the power grid.

[0003] In the test method of the large-capacity energy storage type test power supply, the amplitude of the first wave is usually required to have a certain degree of overshoot amplitude, and to decay to the standard amplitude through several cycles, so as to simulate the instantaneous demand of the real working condition, thereby facilitating the verification of the action speed of the protection device and quickly exposing the weak link of the power device. However, in the existing method for controlling the first-wave peak value of the large-capacity energy storage type test power supply, the first-wave amplitude cannot meet the overshoot amplitude requirement, and it is difficult to effectively improve the first-wave amplitude without significantly increasing the hardware cost of the large-capacity energy storage type test power supply. SUMMARY

[0004] The purpose of the present application is to overcome the defect in the prior art that it is difficult to effectively improve the first-wave amplitude of the test voltage output by the large-capacity energy storage type test power supply without significantly increasing the hardware cost, and to provide a method for controlling the first-wave peak value of the large-capacity energy storage type test power supply.

[0005] The purpose of the present application is achieved by the following technical solution: The method for controlling the first-wave peak value of the large-capacity energy storage type test power supply comprises the following steps: Step 1, a standard SPWM pulse signal is applied to each sub-power unit of the power unit, and the single-phase voltage output by each sub-power unit is cascaded and superimposed to make the large-capacity energy storage type test power supply output a test voltage; Step 2, collect the test waveform of the first predetermined number of standard SPWM pulse signals of the test voltage, determine whether the peak value of the test waveform exceeds the predetermined peak threshold value, if it exceeds the predetermined peak threshold value, do not operate, if it does not exceed the predetermined peak threshold value, execute step 3; Step 3, determine the peak value adjustment ratio based on the difference between the peak value of the test waveform and the predetermined peak threshold value; Step 4, process the direct current component adjustment value of the standard SPWM pulse signal based on the peak value adjustment ratio, and superimpose it to the first predetermined number of standard SPWM pulse signals, to obtain the SPWM pulse signal superimposed with the direct current component; Step 5, provide the SPWM pulse signal superimposed with the direct current component to each sub-power unit, so that the peak value of the test waveform of the first predetermined number of standard SPWM pulse signals output by the large-capacity energy storage test power supply exceeds the predetermined peak threshold value.

[0006] As a preferred, in step 1, the standard SPWM pulse signal is applied to each sub-power unit, specifically: The control system applies the standard SPWM pulse signal to the control electrode of the IGBT of each sub-power unit, the standard SPWM pulse signal controls the on / off time of the IGBT, so that a series of pulses with width changing according to the sine rule are generated at the output end, the equivalent effect of the pulse is close to the sine wave, which simulates the test voltage waveform required for testing.

[0007] As a preferred, in step 3, the peak value adjustment ratio is calculated as follows: Peak value adjustment ratio=(predetermined peak threshold value-test waveform peak value) / predetermined peak threshold value.

[0008] As a preferred, step 4 is specifically: Based on the peak value adjustment ratio and the amplitude of the standard SPWM pulse signal, calculate the direct current component adjustment value for adjusting the standard SPWM pulse signal; Based on the first predetermined number of standard SPWM pulse signals and the time slice division number of each standard SPWM pulse signal, the direct current component adjustment value is gradually decreased in voltage value in each time slice, and the corresponding direct current component adjustment value of the last time slice of the last SPWM pulse signal in the first predetermined number is 0; Superimpose the direct current component adjustment value with the voltage value gradually decreased in each time slice on the first predetermined number of standard SPWM pulse signals according to the corresponding time slice, to obtain the SPWM pulse signal superimposed with the direct current component.

[0009] As preferred, the time slice division quantity in step 5 is specifically represented as that each standard SPWM pulse signal is divided into a second predetermined number of time slices, and the total time slices are the product of the first predetermined number and the time slice division quantity of each standard SPWM pulse signal.

[0010] As preferred, the time slice division quantity is dynamically adjusted according to the frequency of the test voltage, and the higher the frequency, the more the time slice division quantity.

[0011] The large-capacity energy storage test power supply is suitable for the method for controlling the first wave peak value of the large-capacity energy storage test power supply, which comprises a control system, a power unit, a capacitor unit, an output contactor and an output sampling unit, the control system is connected with the power unit, the output contactor and the output sampling unit respectively, the power unit is connected with the capacitor unit, and the capacitor unit is also connected with the output contactor; the control system is used for executing each step of the method for controlling the first wave peak value of the large-capacity energy storage test power supply, the output end of the output contactor is connected with a device to be tested, and is used for controlling the output on-off of the test voltage to the device to be tested; and the output sampling unit is used for collecting the test waveform of the test voltage and feeding back to the control system.

[0012] As preferred, the power unit comprises a plurality of sub-power units, each sub-power unit comprises a rectifier unit and an inverter unit, the rectifier unit is connected with a corresponding energy storage capacitor in the capacitor unit, and is used for charging the energy storage capacitor after rectifying alternating current energy; the input end of the inverter unit is connected with the corresponding energy storage capacitor, the output end is connected with the input end of the output contactor after cascading, and the control electrode of the IGBT of the inverter unit is connected with the control system through optical fiber control, and is used for receiving the SPWM pulse signal output by the control system and inverting the direct current energy of the energy storage capacitor into alternating current test voltage.

[0013] As preferred, the capacitor unit comprises a plurality of energy storage capacitors, each energy storage capacitor is connected with the output end of the rectifier unit and the input end of the inverter unit of the corresponding sub-power unit in the power unit, and is used for storing the energy processed by the rectifier unit and providing energy support for the inverter unit.

[0014] As preferred, the energy storage capacitor is a filter capacitor, a DC-Link capacitor or a super capacitor.

[0015] A storage medium, wherein computer executable instructions are stored in the storage medium, when the computer executable instructions are loaded and executed by a processor, the steps of the method for controlling the first wave peak value of the large-capacity energy storage test power supply are realized.

[0016] The beneficial effects of the present application are: the complete process of the present application, which comprises applying a standard SPWM pulse signal, collecting test waveforms, judging peak values, calculating adjustment ratio and DC component, and outputting adjusted pulse signals, can effectively increase the first peak value of the output test voltage to a predetermined threshold without significantly increasing the hardware cost of the large-capacity energy storage test power supply, meet the instantaneous peak value resistance test requirements of the devices to be tested such as transformers and switching devices, and accurately simulate the instantaneous impact scene under real working conditions.

[0017] By gradually decreasing the DC component adjustment value to 0 in time slices, the first peak value is smoothly transitioned from overshoot state to standard amplitude, avoiding the impact of peak value mutation on power units and devices to be tested, reducing the stress damage risk of power devices, prolonging the service life of the power supply system and the devices to be tested, and improving the safety of the test process.

[0018] The overall first peak value control is realized by uniformly adjusting the SPWM pulse signal, without the need for independent modification of individual sub-power units, compatible with energy storage test power supplies of different cascade numbers and different capacities, wide application range, and can meet the diversified test scene requirements.

[0019] The entire control process realizes dynamic adjustment of the SPWM pulse signal through software algorithm, without the need for additional power devices or energy storage elements, simplifying the hardware structure of the power supply system, reducing production and maintenance costs, and being easy to realize through firmware upgrade on the existing energy storage test power supply, with low modification difficulty and strong popularization. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flowchart of the present application; Figure 2 is a circuit principle connection diagram of the large-capacity energy storage test power supply of the present application; Figure 3 is a connection circuit schematic diagram of a single energy storage capacitor and a single sub-power unit. DETAILED DESCRIPTION

[0021] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the gist of the example implementations to those skilled in the art.

[0022] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0023] The block diagrams shown in the drawings are functional entities, which do not necessarily have to correspond to physically independent entities. That is, these functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0024] The flowcharts shown in the drawings are only illustrative, and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0025] Embodiment: a method for controlling the first peak value of a large-capacity energy storage test power supply, as shown in Figure 1 comprises the following steps: Step 1, apply a standard SPWM pulse signal to each sub-power unit of the power unit, and the single-phase voltage output by each sub-power unit is cascaded and superimposed to make the large-capacity energy storage test power supply output a test voltage; Step 2, collect the test waveform of the first predetermined number (e.g. 5 to 10) of standard SPWM pulse signals of the test voltage, and determine whether the peak value of the test waveform exceeds a predetermined peak threshold value. If it exceeds the predetermined peak threshold value, no operation is performed, and if it does not exceed the predetermined peak threshold value, Step 3 is performed; Step 3, determine the peak value adjustment ratio based on the difference between the peak value of the test waveform and the predetermined peak threshold value; Step 4, based on the peak value adjustment ratio and the amplitude of the standard SPWM pulse signal, calculate a direct current component adjustment value for adjusting the standard SPWM pulse signal; Step 5, based on the first predetermined number of standard SPWM pulse signals and the time slice division number of each standard SPWM pulse signal, make the direct current component adjustment value decrease in voltage value piece by piece, and the corresponding direct current component adjustment value of the last time slice of the last SPWM pulse signal in the first predetermined number is 0; Step 6, adjust the direct current component adjustment value of the gradually decreasing voltage value according to the corresponding time slice to the first predetermined number of standard SPWM pulse signals to obtain the SPWM pulse signal superimposed with the direct current component; Step 7, provide the SPWM pulse signal superimposed with the direct current component to each sub-power unit, so that the peak of the test waveform of the first predetermined number of standard SPWM pulse signals output by the large-capacity energy storage test power supply exceeds the predetermined peak threshold.

[0026] In step 1, the standard SPWM pulse signal is applied to each sub-power unit, specifically: The control system applies the standard SPWM pulse signal to the control electrode of the IGBT of each sub-power unit, and the standard SPWM pulse signal controls the on / off time of the IGBT, so that a series of pulses with varying widths according to the sine law are generated at the output end, and the equivalent effect of the pulses is close to the sine wave, simulating the test voltage waveform required for testing.

[0027] In step 3, the peak adjustment ratio is calculated as follows: Peak adjustment ratio = (predetermined peak threshold - peak value of test waveform) / predetermined peak threshold. For example, if it is determined that the peak value of the test waveform corresponding to the first predetermined number is only 80% of the predetermined peak threshold, then the peak adjustment ratio is 20%.

[0028] In step 4, if the amplitude of the standard SPWM pulse signal is The peak adjustment ratio k, and the direct current component adjustment value . = 。

[0029] In step 5, the time slice division number is specifically represented as each standard SPWM pulse signal is divided into a second predetermined number of time slices, and the total time slice is the product of the first predetermined number and the time slice division number of each standard SPWM pulse signal.

[0030] Specifically, the time corresponding to the first predetermined number of standard SPWM pulse signals (for example, 5 standard SPWM pulse signals) is divided into a second predetermined number of time slices (for example, each standard SPWM pulse signal is divided into 10 time slices, and 5 SPWM pulse signals are cumulatively divided into 50 time slices); and in the time span corresponding to the second predetermined number of time slices (50 time slices), the calculated direct current component adjustment value is from = The voltage value decreases gradually in time slices until the direct current component adjustment value corresponding to the second predetermined number of time slices (for example, the 50th time slice) is "0".

[0031] The number of time slices is dynamically adjusted according to the frequency of the test voltage. The higher the frequency, the more time slices are divided.

[0032] A large-capacity energy storage test power supply is suitable for a method for controlling the first wave peak value of the large-capacity energy storage test power supply, such as Figure 2 As shown, it includes a control system, a power unit, a capacitor unit, an output contactor and an output sampling unit. The control system is connected to the power unit, the output contactor and the output sampling unit respectively, the power unit is connected to the capacitor unit, and the capacitor unit is also connected to the output contactor; the control system is used to execute the various steps of the method for controlling the first wave peak value of the large-capacity energy storage test power supply, the output end of the output contactor is connected to the device to be tested, and is used to control the output of the test voltage to the device to be tested; the output sampling unit is used to collect the test waveform of the test voltage and feed it back to the control system. The large-capacity energy storage test power supply also includes a main switch, a main AC contactor, a pre-charging circuit, a charging unit, a step-up transformer and a human-machine interface. The input end of the main switch is connected to an external power supply (such as single / three-phase AC380V, 50Hz or 60Hz), and the output end is respectively connected to the input end of the pre-charging circuit and the main AC contactor, for controlling the on and off of the main circuit of the power supply; the output end of the pre-charging circuit is connected in parallel with the output end of the main AC contactor and then connected to the input end of the charging unit, for limiting the inrush current in the initial charging stage of the capacitor unit to protect the capacitor unit; the output end of the charging unit is connected to the primary side of the step-up transformer, for processing the input electrical energy and transmitting it to the step-up transformer; the secondary side winding of the step-up transformer is connected one-to-one with the rectifier unit of each sub-power unit in the power unit, for stepping up the output voltage of the charging unit and providing it to the rectifier unit; the human-machine interface is connected to the control system, for receiving parameters such as the predetermined peak threshold, the first predetermined number, the second predetermined number, etc. input by the user, and displaying the test waveform, peak data and adjustment status.

[0033] The power unit includes multiple sub-power units, each of which includes a rectifier unit and an inverter unit. The rectifier unit is connected to the corresponding energy storage capacitor in the capacitor unit, and is used to rectify the AC power to charge the energy storage capacitor; the input end of the inverter unit is connected to the corresponding energy storage capacitor, and the output end is connected to the input end of the output contactor after cascading. The IGBT control electrode of the inverter unit is connected to the control system through optical fiber control, and is used to receive the SPWM pulse signal output by the control system and invert the DC power of the energy storage capacitor into an AC test voltage.

[0034] The capacitor unit includes several energy storage capacitors, each of which is connected to the output end of the rectifier unit and the input end of the inverter unit of the corresponding sub-power unit in the power unit, and is used to store the electric energy processed by the rectifier unit and provide energy support for the inverter unit.

[0035] The connection circuit schematic diagram of a single energy storage capacitor and a single sub-power unit is shown in Figure 1, wherein a, b, and c are connected to three phases of an input power supply, respectively; a three-phase bridge rectifier circuit composed of six diodes D is shown on the left side of the figure, which rectifies three-phase alternating current power into direct current power; the capacitor C is an energy storage capacitor, which receives the rectified direct current power and provides energy support for the inverter unit on the right side. Each sub-power unit adopts the structure of an H-bridge, ac1 and ac2 are the output terminals of the inverter unit of the sub-power unit, g1, g2, g3, and g4 are the control electrodes of four IGBT modules, and when the control system applies an SPWM pulse signal, the output terminals ac1 and ac2 can output a single-phase sine wave pulse width modulation output voltage. When multiple sub-power units are cascaded, the total output test voltage can be obtained. Figure 3

[0036] The energy storage capacitor is a filter capacitor, a DC-Link capacitor, or a super capacitor.

[0037] A storage medium, wherein computer executable instructions are stored in the storage medium, and when the computer executable instructions are loaded and executed by a processor, the steps of the method for controlling the first peak value of a large-capacity energy storage test power supply are implemented.

[0038] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the application be limited only by the scope of the claims, including any appropriate equivalents.

[0039] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims that follow.​

Claims

1. A method for controlling the first wave peak value of a large-capacity energy storage test power supply, characterized in that: The following steps are involved: Step 1: Apply a standard SPWM pulse signal to each sub-power unit. The single-phase voltage output by each sub-power unit is cascaded and superimposed to enable the large-capacity energy storage test power supply to output a test voltage. Step 2, collecting a test waveform of a first predetermined number of standard SPWM pulse signals of the test voltage, and determining whether the peak value of the test waveform exceeds a predetermined peak value threshold value, if so, no operation is performed, and if not, executing step 3; Step 3, determining a peak adjustment ratio based on a difference between a peak value of the test waveform and a predetermined peak threshold value; Step 4, processing the DC component adjustment value of the standard SPWM pulse signal based on the peak adjustment ratio, and adding the DC component adjustment value to a first predetermined number of standard SPWM pulse signals to obtain an adjusted SPWM pulse signal; Step 5: Provide the SPWM pulse signal with superimposed DC component to each sub-power unit, so that the peak of the test waveform of the first predetermined number of standard SPWM pulse signals output by the large-capacity energy storage test power supply exceeds a predetermined peak threshold.

2. The method for controlling the first wave peak value of a large-capacity energy storage test power supply according to claim 1, wherein: In step 1, a standard SPWM pulse signal is applied to each sub-power unit, specifically: The control system applies a standard SPWM pulse signal to the control electrode of the IGBT of each sub-power unit. The standard SPWM pulse signal controls the on / off time of the IGBT, causing the output end to generate a series of pulses whose width varies according to the sinusoidal law. The equivalent effect of the pulse is close to that of a sine wave, simulating the test voltage waveform required for the test.

3. The method for controlling the first wave peak value of a large-capacity energy storage test power supply according to claim 1, wherein: In step 3, the peak adjustment ratio is calculated as follows: Peak adjustment ratio = (predetermined peak threshold - peak value of test waveform) / predetermined peak threshold.

4. The method for controlling the first wave peak value of a large-capacity energy storage test power supply according to claim 1, wherein: The step 4 is specifically as follows: Calculating a DC component adjustment value for adjusting the standard SPWM pulse signal based on the peak adjustment ratio and the amplitude of the standard SPWM pulse signal; Based on a first predetermined number of standard SPWM pulse signals and the number of time slices of each standard SPWM pulse signal, the DC component adjustment value is reduced in voltage by time slice, so that the DC component adjustment value corresponding to the last time slice of the last SPWM pulse signal in the first predetermined number is 0; The DC component adjustment value whose voltage value decreases in each time slice is superimposed on a first predetermined number of standard SPWM pulse signals according to the corresponding time slice to obtain an SPWM pulse signal with a superimposed DC component.

5. The method for controlling the first wave peak value of a large-capacity energy storage test power supply according to claim 4, wherein: The number of time slices specifically indicates that each standard SPWM pulse signal is equally divided into a second predetermined number of time slices, and the total time slices are the product of the first predetermined number and the number of time slices of each standard SPWM pulse signal.

6. The method for controlling the first wave peak value of a large-capacity energy storage test power supply according to claim 5, wherein: The number of time slices is dynamically adjusted according to the frequency of the test voltage. The higher the frequency, the more time slices are divided.

7. A large-capacity energy storage test power supply, suitable for a method for controlling the first wave peak value of a large-capacity energy storage test power supply, characterized in that: The invention comprises a control system, a power unit, a capacitor unit, an output contactor and an output sampling unit, wherein the control system is respectively connected to the power unit, the output contactor and the output sampling unit, the power unit is connected to the capacitor unit, and the capacitor unit is also connected to the output contactor; the control system is used to execute the steps of the method for controlling the first wave peak value of a large-capacity energy storage test power supply as described in any one of claims 1 to 6, the output end of the output contactor is connected to the device to be tested, and is used to control the output on and off of the test voltage to the device to be tested; the output sampling unit is used to collect the test waveform of the test voltage and feed it back to the control system.

8. The large-capacity energy storage test power supply according to claim 7, characterized in that: The power unit includes multiple sub-power units, each of which includes a rectifier unit and an inverter unit. The rectifier unit is connected to the corresponding energy storage capacitor in the capacitor unit, and is used to rectify the AC power to charge the energy storage capacitor; the input end of the inverter unit is connected to the corresponding energy storage capacitor, and the output end is connected to the input end of the output contactor after cascading. The IGBT control electrode of the inverter unit is connected to the control system through optical fiber control, and is used to receive the SPWM pulse signal output by the control system and invert the DC power of the energy storage capacitor into an AC test voltage.

9. The large-capacity energy storage test power supply according to claim 8, characterized in that: The capacitor unit includes several energy storage capacitors, each of which is connected to the output end of the rectifier unit and the input end of the inverter unit of the corresponding sub-power unit in the power unit, and is used to store the electric energy processed by the rectifier unit and provide energy support for the inverter unit.

10. The large-capacity energy storage test power supply according to claim 9, characterized in that: The energy storage capacitor is a filter capacitor, a DC-Link capacitor or a supercapacitor.

11. A storage medium, characterized in that: The storage medium stores computer executable instructions, which, when loaded and executed by the processor, implement the steps of the method for controlling the first wave peak value of a large-capacity energy storage test power supply as described in any one of claims 1 to 5.

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