Method for controlling the first peak of a high-capacity energy storage test power supply

Abstract

The application discloses a method for controlling the first wave peak value of a large-capacity energy storage test power supply, wherein a standard SPWM pulse signal is first applied to each sub-power unit of a power unit, and test voltage is output after the cascaded superposition of sub-unit output voltages; the test waveform of a first predetermined number of pulse signals is collected, and it is judged whether the peak value exceeds a predetermined threshold value; if not, the process continues; the adjustment ratio is determined based on the peak value difference, and the DC component adjustment value is calculated in combination with the amplitude of the standard SPWM pulse signal; the DC component is gradually decreased in time slices according to the number of time slice divisions, and the last time slice of the last pulse signal of the first predetermined number is 0; the decreased DC component is superimposed on the corresponding pulse signal to obtain a new SPWM pulse signal; and the new SPWM pulse signal is provided to the sub-power unit, so that the first wave peak value exceeds the threshold value. The application effectively improves the first wave peak value of the output test voltage to the predetermined threshold value, and meets the instantaneous peak value resistance test requirements of devices to be tested such as transformers and switching devices.

Description

Technical Field

[0001] This invention relates to the field of power testing technology, and in particular to a method for controlling the initial peak value of a large-capacity energy storage test power supply. Background Technology

[0002] Existing high-capacity energy storage test power supplies typically include at least: a contactor, a charging unit, a step-up transformer, a supercapacitor unit, and a power unit. During energy storage, the high-capacity energy storage test power supply powers the charging unit via a three-phase power supply through the contactor. The output of the charging unit is connected to the step-up transformer. The voltage boosted by the transformer is then rectified by the power unit to charge the supercapacitor unit. During testing, the energy stored in the supercapacitor unit is converted by the power unit's inverter unit, and a test voltage is output for testing the device under test (DUT). Examples of DUTs include transformers and low-voltage switches. Tests performed include transformer short-circuit tests and current withstand tests on switchgear. Because short-time and peak current withstand tests are completed using the energy stored in the supercapacitor unit, there is no impact on the power grid.

[0003] In testing methods for high-capacity energy storage test power supplies, it is typically required that the initial amplitude have a certain degree of overshoot, decaying to the standard amplitude over several cycles. This is to simulate the instantaneous demands of real-world operating conditions, thereby facilitating the verification of protection device response speed and quickly exposing weaknesses in power devices. However, existing methods for controlling the initial peak value of high-capacity energy storage test power supplies sometimes fail to meet the overshoot requirements, and it is difficult to effectively improve the initial amplitude without significantly increasing the hardware cost of the high-capacity energy storage test power supply. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies in effectively increasing the initial amplitude of the test voltage output by a large-capacity energy storage test power supply without significantly increasing hardware costs, and to provide a method for controlling the initial peak value of a large-capacity energy storage test power supply.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for controlling the initial peak value of a large-capacity energy storage test power supply includes the following steps:

[0007] Step 1: Apply a standard SPWM pulse signal to each sub-power unit of the power unit. The single-phase voltage output by each sub-power unit is cascaded and superimposed to make the high-capacity energy storage test power supply output the test voltage.

[0008] Step 2: Acquire the test waveform of the first predetermined number of standard SPWM pulse signals of the test voltage, and determine whether the peak value of the test waveform exceeds the predetermined peak value threshold. If it exceeds the predetermined peak value threshold, no operation is performed. If it does not exceed the predetermined peak value threshold, proceed to step 3.

[0009] Step 3: Determine the peak adjustment ratio based on the difference between the peak value of the test waveform and the predetermined peak value threshold;

[0010] Step 4: Based on the peak adjustment ratio, process the DC component adjustment value of the standard SPWM pulse signal and superimpose it onto the first predetermined number of standard SPWM pulse signals to obtain the adjusted SPWM pulse signal;

[0011] Step 5: Provide an 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 high-capacity energy storage test power supply exceeds a predetermined peak threshold.

[0012] Preferably, in step 1, applying a standard SPWM pulse signal to each sub-power unit specifically involves:

[0013] The control system applies a standard SPWM pulse signal to the control electrode of the IGBT in each sub-power unit. The standard SPWM pulse signal controls the on / off time of the IGBT, so that the output terminal generates a series of pulses with a width that varies according to a sine law. The equivalent effect of the pulse is close to a sine wave, simulating the test voltage waveform required for the test.

[0014] Preferably, in step 3, the peak adjustment ratio is calculated as follows:

[0015] Peak adjustment ratio = (predetermined peak threshold - peak value of test waveform) / predetermined peak threshold.

[0016] Preferably, step 4 specifically includes:

[0017] Based on the peak adjustment ratio and the amplitude of the standard SPWM pulse signal, calculate the DC component adjustment value used to adjust the standard SPWM pulse signal;

[0018] Based on a first predetermined number of standard SPWM pulse signals and the number of time slices for each standard SPWM pulse signal, the DC component adjustment value is reduced by voltage value time slice by time slice, so that the corresponding DC component adjustment value of the last time slice of the last SPWM pulse signal in the first predetermined number is 0.

[0019] According to the corresponding time slice, the DC component adjustment value, which decreases with each time slice, is superimposed on the first predetermined number of standard SPWM pulse signals to obtain an SPWM pulse signal with superimposed DC component.

[0020] Preferably, in step 5, the number of time slices is specifically represented as each standard SPWM pulse signal being equally divided into a second predetermined number of time slices, and the total number of time slices being the product of the first predetermined number and the number of time slices for each standard SPWM pulse signal.

[0021] Preferably, 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.

[0022] A high-capacity energy storage test power supply is provided, along with a method for controlling the initial peak value of the high-capacity energy storage test power supply. The power supply 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. The power unit is connected to the capacitor unit, and the capacitor unit is also connected to the output contactor. The control system executes the steps of the method for controlling the initial peak value of the high-capacity energy storage test power supply. The output terminal of the output contactor is connected to the device under test (DUT) and is used to control the on / off state of the test voltage output to the DUT. The output sampling unit acquires the test waveform of the test voltage and feeds it back to the control system.

[0023] Preferably, 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 terminal of the inverter unit is connected to the corresponding energy storage capacitor, and the output terminal is connected to the input terminal of the output contactor after cascading. The IGBT control electrode of the inverter unit is connected to the control system through optical fiber control to receive the SPWM pulse signal output by the control system and invert the DC power of the energy storage capacitor into AC test voltage.

[0024] Preferably, the capacitor unit includes several energy storage capacitors, each of which is connected to the output terminal of the rectifier unit and the input terminal of the inverter unit of the corresponding sub-power unit in the power unit, for storing electrical energy processed by the rectifier unit and providing energy support for the inverter unit.

[0025] Preferably, the energy storage capacitor is a filter capacitor, a DC-Link capacitor, or a supercapacitor.

[0026] A storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the method for controlling the first peak value of a large-capacity energy storage test power supply.

[0027] The beneficial effects of this invention are: by applying a standard SPWM pulse signal, acquiring test waveforms and determining peak values, calculating adjustment ratios and DC components, and outputting the adjusted pulse signal, this invention can effectively improve the first peak value of the output test voltage to a predetermined threshold without significantly increasing the hardware cost of large-capacity energy storage test power supplies, thus meeting the instantaneous peak withstand test requirements for transformers, switching equipment, and other test equipment, and accurately simulating instantaneous impact scenarios under real working conditions.

[0028] By gradually decreasing the DC component adjustment value to 0 over time slices, the initial peak value smoothly transitions from an overshoot state to the standard amplitude, avoiding the impact of peak abrupt changes on the power unit and the device under test, reducing the risk of stress damage to power devices, extending the service life of the power system and the device under test, and improving the safety of the testing process.

[0029] The overall first-wave peak control is achieved by uniformly adjusting the SPWM pulse signal, without the need for independent modification of individual sub-power units. It is compatible with energy storage test power supplies of different cascade numbers and capacities, has a wide range of applications, and can meet the needs of diverse test scenarios.

[0030] The entire control process achieves dynamic adjustment of the SPWM pulse signal through software algorithms, without the need to add additional power devices or energy storage components. This simplifies the hardware structure of the power supply system, reduces production and maintenance costs, and is easy to implement on existing energy storage test power supplies through firmware upgrades. The modification is simple and has strong applicability. Attached Figure Description

[0031] Figure 1 This is a flowchart of the present invention;

[0032] Figure 2 This is a circuit diagram of the high-capacity energy storage test power supply of the present invention.

[0033] Figure 3 This is a schematic diagram of the connection circuit between a single energy storage capacitor and a single sub-power unit of the present invention. Detailed Implementation

[0034] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0035] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0036] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0037] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0038] Example: A method for controlling the initial peak value of a large-capacity energy storage test power supply, such as... Figure 1 As shown, it includes the following steps:

[0039] Step 1: Apply a standard SPWM pulse signal to each sub-power unit of the power unit. The single-phase voltage output by each sub-power unit is cascaded and superimposed to make the high-capacity energy storage test power supply output the test voltage.

[0040] Step 2: Collect the test waveform of a 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 value threshold. If it exceeds the predetermined peak value threshold, no operation is performed; if it does not exceed the predetermined peak value threshold, proceed to step 3.

[0041] Step 3: Determine the peak adjustment ratio based on the difference between the peak value of the test waveform and the predetermined peak value threshold;

[0042] Step 4: Based on the peak adjustment ratio and the amplitude of the standard SPWM pulse signal, calculate the DC component adjustment value used to adjust the standard SPWM pulse signal;

[0043] Step 5: Based on the first predetermined number of standard SPWM pulse signals and the number of time slices for each standard SPWM pulse signal, the DC component adjustment value is decreased by the voltage value time slice by time slice, so that the corresponding DC component adjustment value of the last time slice of the last SPWM pulse signal in the first predetermined number is 0.

[0044] Step 6: According to the corresponding time slice, the DC component adjustment value of the voltage value decreasing time slice by time slice is superimposed on the first predetermined number of standard SPWM pulse signals to obtain the SPWM pulse signal with superimposed DC component.

[0045] Step 7: Provide an 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 high-capacity energy storage test power supply exceeds a predetermined peak threshold.

[0046] In step 1, a standard SPWM pulse signal is applied to each sub-power unit, specifically as follows:

[0047] The control system applies a standard SPWM pulse signal to the control electrode of the IGBT in each sub-power unit. The standard SPWM pulse signal controls the on / off time of the IGBT, so that the output terminal generates a series of pulses with a width that varies according to a sine law. The equivalent effect of the pulse is close to a sine wave, simulating the test voltage waveform required for the test.

[0048] In step 3, the peak adjustment ratio is calculated as follows:

[0049] 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%.

[0050] In step 4, if the amplitude of the standard SPWM pulse signal = Peak adjustment ratio = k, DC component adjustment value = .but, = 。

[0051] In step 5, the number of time slices is specifically represented by each standard SPWM pulse signal being divided into a second predetermined number of time slices, and the total number of time slices being the product of the first predetermined number and the number of time slices for each standard SPWM pulse signal.

[0052] Specifically, the time corresponding to a first predetermined number of standard SPWM pulse signals (e.g., 5 standard SPWM pulse signals) is divided into a second predetermined number of time slices (e.g., each standard SPWM pulse signal is divided into 10 time slices, and the 5 SPWM pulse signals are cumulatively divided into 50 time slices); and within the time span corresponding to the second predetermined number of time slices (50 time slices), the calculated DC component adjustment value is adjusted from... = The voltage value is decreased time-by-time until the DC component adjustment value corresponding to the second predetermined number of time slices (e.g., the 50th time slice) is "0".

[0053] 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.

[0054] A method for controlling the initial peak value of a large-capacity energy storage test power supply, such as... Figure 2 As shown, the system 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. 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 peak value of a large-capacity energy storage test power supply. The output terminal of the output contactor is connected to the device under test (DUT) and is used to control the on / off state of the test voltage output to the DUT. The output sampling unit is used to acquire the test waveform of the test voltage and feed it back to the control system. The high-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 terminal of the main switch is connected to an external power supply (such as single / three-phase AC380V, 50Hz or 60Hz), and the output terminal is connected to the input terminals of the pre-charging circuit and the main AC contactor, respectively, to control the on / off state of the main power supply circuit. The output terminal of the pre-charging circuit is connected in parallel with the output terminal of the main AC contactor and then connected to the input terminal of the charging unit to limit the inrush current and protect the capacitor unit during the initial charging stage. The output terminal of the charging unit is connected to the primary side of the step-up transformer to process the input electrical energy and transmit it to the step-up transformer. The secondary winding of the step-up transformer is connected one-to-one with the rectifier unit of each sub-power unit in the power unit to boost the output voltage of the charging unit and provide it to the rectifier unit. The human-machine interface is connected to the control system to receive user-input parameters such as the predetermined peak threshold, the first predetermined quantity, and the second predetermined quantity, and to display the test waveform, peak data, and adjustment status.

[0055] The power unit includes multiple sub-power units, each containing 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 AC power to charge the energy storage capacitor. The input terminal of the inverter unit is connected to the corresponding energy storage capacitor, and the output terminal is connected to the input terminal of the output contactor after cascading. The IGBT control electrode of the inverter unit is connected to the control system through optical fiber control to receive the SPWM pulse signal output by the control system and invert the DC power of the energy storage capacitor into AC test voltage.

[0056] The capacitor unit includes several energy storage capacitors. Each energy storage capacitor is connected to the output terminal of the rectifier unit and the input terminal of the inverter unit of the corresponding sub-power unit in the power unit. It is used to store the electrical energy processed by the rectifier unit and provide energy support for the inverter unit.

[0057] The connection circuit diagram of a single energy storage capacitor and a single sub-power unit is shown below. Figure 3 As shown, a, b, and c are connected to the three phases of the input power supply. The left side of the diagram consists of a three-phase bridge rectifier circuit composed of six diodes (D) to rectify the three-phase AC power into DC power. Capacitor C is an energy storage capacitor that receives the rectified DC power, providing energy support for the inverter unit on the right. Each sub-power unit adopts an H-bridge structure. ac1 and ac2 are the output terminals of the inverter unit of the sub-power unit, and g1, g2, g3, and g4 are the control terminals of four IGBT modules. When the control system applies an SPWM pulse signal, the output terminals ac1 and ac2 can output a single-phase sinusoidal pulse width modulated output voltage. When multiple sub-power units are cascaded, the total output test voltage can be obtained.

[0058] The energy storage capacitor is a filter capacitor, a DC-Link capacitor, or a supercapacitor.

[0059] A storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the method for controlling the first peak value of a large-capacity energy storage test power supply.

[0060] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0061] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for controlling the initial peak value of a large-capacity energy storage test power supply, characterized in that, Includes the following steps: 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 make the high-capacity energy storage test power supply output the test voltage. Step 2: Acquire the test waveform of the first predetermined number of standard SPWM pulse signals of the test voltage, and determine whether the peak value of the test waveform exceeds the predetermined peak value threshold. If it exceeds the predetermined peak value threshold, no operation is performed. If it does not exceed the predetermined peak value threshold, proceed to step 3. Step 3: Determine the peak adjustment ratio based on the difference between the peak value of the test waveform and the predetermined peak value threshold; Step 4: Based on the peak adjustment ratio, process the DC component adjustment value of the standard SPWM pulse signal and superimpose it onto the first predetermined number of standard SPWM pulse signals to obtain the adjusted SPWM pulse signal; Step 5: Provide an 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 high-capacity energy storage test power supply exceeds a predetermined peak threshold.

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

3. The method for controlling the first peak value of a large-capacity energy storage test power supply according to claim 1, characterized in that, 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 peak value of a large-capacity energy storage test power supply according to claim 1, characterized in that, Step 4 specifically includes: Based on the peak adjustment ratio and the amplitude of the standard SPWM pulse signal, calculate the DC component adjustment value used to adjust the standard SPWM pulse signal; Based on a first predetermined number of standard SPWM pulse signals and the number of time slices for each standard SPWM pulse signal, the DC component adjustment value is reduced by voltage value time slice by time slice, so that the corresponding DC component adjustment value of the last time slice of the last SPWM pulse signal in the first predetermined number is 0. According to the corresponding time slice, the DC component adjustment value, which decreases with each time slice, is superimposed on the first predetermined number of standard SPWM pulse signals to obtain an SPWM pulse signal with superimposed DC component.

5. The method for controlling the first peak value of a large-capacity energy storage test power supply according to claim 4, characterized in that, The number of time slices is specifically represented by each standard SPWM pulse signal being divided into a second predetermined number of time slices, and the total number of time slices being the product of the first predetermined number and the number of time slices for each standard SPWM pulse signal.

6. The method for controlling the first peak value of a large-capacity energy storage test power supply according to claim 5, characterized in that, 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 high-capacity energy storage test power supply, suitable for a method to control the initial peak value of a high-capacity energy storage test power supply, characterized in that... The device 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. 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 peak value of a large-capacity energy storage test power supply according to any one of claims 1-6. The output terminal of the output contactor is connected to the device under test (DUT) and is used to control the on / off output of the test voltage to the DUT. The output sampling unit is used to acquire the test waveform of the test voltage and feed it back to the control system.

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

9. The high-capacity energy storage test power supply according to claim 8, characterized in that, The capacitor unit includes several energy storage capacitors. Each energy storage capacitor is connected to the output terminal of the rectifier unit and the input terminal of the inverter unit of the corresponding sub-power unit in the power unit. It is used to store the electrical energy processed by the rectifier unit and provide energy support for the inverter unit.

10. The high-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 a processor, implement the steps of the method for controlling the first 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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