Method for Locating Electromagnetic Interference during Matching of Energy Storage Unit and Energy Storage Inverter

Abstract

The present invention provides a method for locating electromagnetic interference when an energy storage unit is matched with an energy storage inverter, including the following steps: 1) When the IGBT module 3 is working, view the detected voltage and temperature signals through the upper computer 7; 2) Arrange another identical detection circuit board 5 in the external exposed space, view the detected voltage and temperature signals, and judge whether the signals are abnormal; 3) Stop the clock operation of the detection circuit board 5 inside the capacitor bank 4 through software, view the detected voltage and temperature signals, and judge whether the signals are abnormal; 4) Start the IGBT module 3, measure the voltage signals at the positive and negative poles of its DC side, and view whether the differential mode voltage is stable and whether the voltages of the positive and negative poles to PE are stable; 5) Complete the location of the source of electromagnetic interference. The present invention has the following advantages: The present invention can accurately and quickly locate the source of electromagnetic interference.

Description

Technical Field

[0001] The present invention belongs to the field of dynamic power voltage stabilization systems, and particularly relates to a method for locating electromagnetic interference when an energy storage unit is matched with an energy storage inverter. Background Art

[0002] In the existing technology, a dynamic power voltage stabilization system generally consists of two parts. One part is an energy storage inverter, and the other part is a unit for storing and releasing energy. There are two forms of the unit for storing and releasing energy. One is a super capacitor bank, and the other is a battery pack. Both loads have sensors and control circuits responsible for collecting voltage and temperature, establish communication with the upper computer, and upload the real-time monitoring status. Since the integration degree of this capacitor bank or battery pack is relatively high, the control circuit generally has no special protection, so it is easily interfered by electromagnetic phenomena. Then, it is necessary to locate the cause of this electromagnetic interference. Summary of the Invention

[0003] In view of this, the present invention aims to propose a method for locating electromagnetic interference when an energy storage unit is matched with an energy storage inverter, so as to accurately and quickly locate the source of electromagnetic interference.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows:

[0005] A method for locating electromagnetic interference when an energy storage unit is matched with an energy storage inverter includes the following steps:

[0006] 1) Connect the positive and negative poles of the DC side of the IGBT module 3 of the energy storage inverter 1 to the positive and negative poles of the capacitor bank 4 of the energy storage unit 2 respectively through two power cables 9. The detection circuit board 5 inside the capacitor bank 4 is signal-connected to the upper computer 7 through the communication module 6. The energy storage inverter 1 and the energy storage unit 2 are respectively reliably connected to the reference ground through cables. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7;

[0007] 2) Arrange another identical detection circuit board 5 in the external exposed space, and its electrical connection is the same as that of the detection circuit board 5 inside the capacitor bank 4. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7 to judge whether the signals are abnormal;

[0008] 3) Stop the clock operation of the detection circuit board 5 inside the capacitor bank 4 through software. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7 to judge whether the signals are abnormal;

[0009] 4) Start the IGBT module 3, measure the voltage signals of its positive and negative poles on the DC side, and view whether the differential mode voltage is stable and whether the voltages of the positive and negative poles to PE are stable;

[0010] 5) Complete the localization of electromagnetic interference generation

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] The present invention can accurately and quickly locate the source of electromagnetic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0014] Figure 1 is a schematic structural diagram of an existing dynamic power supply voltage stabilization system;

[0015] Figure 2 is the innovative structure of the dynamic power supply voltage stabilization system according to the embodiment of the present invention;

[0016] Figure 3 is a diagram of voltage and temperature data signals detected by the host computer of an existing dynamic power supply voltage stabilization system;

[0017] Figure 4 is a diagram of voltage and temperature data signals detected by the host computer after the software of an existing dynamic power supply voltage stabilization system stops the clock from working;

[0018] Figure 5 is a diagram of the positive and negative voltage signals of the IGBT module 3 and the voltage signals of both poles to PE;

[0019] Figure 6 is a diagram of voltage and temperature data signals detected by the host computer after adding a Y capacitor;

[0020] Figure 7 is another innovative structure of the dynamic power supply voltage stabilization system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0022] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0023] In the existing dynamic power voltage stabilization system, the positive and negative poles of the DC side of the IGBT module 3 of the energy storage inverter 1 are respectively connected to the positive and negative poles of the capacitor bank 4 of the energy storage unit 2 through two power cables 9. The detection circuit board 5 inside the capacitor bank 4 is signal-connected to the upper computer 7 through the communication module 6; the energy storage inverter 1 and the energy storage unit 2 are respectively reliably connected to the reference ground through the first cable 10 and the first cable 8; when the IGBT module 3 works, the upper computer 7 is used to view the voltage and temperature signals detected by the detection circuit board 5.

[0024] When the IGBT module 3 works, the voltage and temperature signals detected by the upper computer 7 will have a jumping phenomenon, such as Figure 3 shown, the data bit is incorrect, affecting the normal monitoring function. When the IGBT is not working, the phenomenon disappears and the data is normal, indicating that there is electromagnetic interference. At this time, the electromagnetic interference can affect the detection circuit board 5 in two ways, space radiation or cable conduction.

[0025] First of all, both the energy storage inverter 1 and the energy storage unit 2 are large cabinets, and the capacitor bank 4 has its own metal shell and is grounded. It is initially judged that the possibility of space radiation is very small.

[0026] To rule out this possibility, another identical detection circuit board 5 (of the same batch) is arranged in the external exposed space, and its electrical connection is the same as that of the detection circuit board 5 inside the capacitor bank 4. When the IGBT module 3 works, the upper computer 7 is used to view the detected voltage and temperature signals to judge whether the signals are abnormal; through testing, the board of the detection circuit board 5 works normally and the signals are normal. From this, it can be determined that the way of electromagnetic interference is through the power cable 9 and is conducted through the power cable 9.

[0027] Considering that the clock signal working frequency of the board of the detection circuit board 5 itself is very high, in order to eliminate the influence of this high frequency, the clock is stopped through software. It is found that when the IGBT module 3 works, the signal still goes wrong, and the upper computer 7 shows data jumping, such as Figure 4 shown, and at this time it is abnormal that there is a signal. So it is more certain that the cable 9 is the only way to generate electromagnetic interference.

[0028] Next, start the IGBT module 3 and measure the voltage signals of the positive and negative poles of its DC side. The differential mode voltage is very stable, while the voltages of the two poles to the PE are stable and periodically jump, with a frequency of about 2.5K and an amplitude of about 920V, as Figure 5 shown.

[0029] When the IGBT module 3 is working, due to the rapid operation of the switching tubes, a large common-mode voltage is generated between the positive and negative electrodes of the capacitor bank with respect to PE, resulting in a strong electromagnetic interference phenomenon, which causes the working environment of the board component monitoring circuit of the detection circuit board 5 to be abnormal and the data to be incorrect. Thus, the problem is located.

[0030] After the electromagnetic interference is located, in this embodiment, the structure of the existing dynamic power supply voltage stabilization system is innovated. There are the following three innovative structures to eliminate the influence of this electromagnetic interference:

[0031] The first structural embodiment: A DC reactor 12 is connected in series on the power cable 9 between the IGBT module 3 and the capacitor bank 4 to suppress the common-mode current, as Figure 2 shown in.

[0032] The second structural embodiment: A magnetic ring is sleeved on the power cable 9 between the IGBT module 3 and the capacitor bank 4 to increase the magnetic resistance and suppress the common-mode current.

[0033] The third structural embodiment: A Y capacitor 13 is added between the electrodes of the capacitor bank 4 and the reference ground PE, as Figure 7 shown. The method for determining the capacitance value of the Y capacitor 13 is: perform FFT analysis on the interference signal, select a suitable capacitance value, and at the same time, the safety regulations issue needs to be considered. Eventually, a suitable compatibility level will be found.

[0034] Adding the Y capacitor 13 is equivalent to adding a common-mode filter between the positive and negative electrodes of the capacitor bank 4 and the ground. The filtering can remove the common-mode harassment voltage. At this time, the IGBT module 3 is controlled to be in the working state. The voltage waveform of the electrodes of the improved capacitor bank 4 with respect to PE is as Figure 5 shown, very stable and without periodic disturbances. The collected signal has no jumps and is normally displayed on the upper computer, and the problem is effectively solved.

[0035] Comparing the above three structures, in the rules of engineering rectification, for the purpose of saving costs and time, usually the third structure, adding the Y capacitor, will be selected.

[0036] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Method for locating electromagnetic interference when energy storage unit is matched with energy storage inverter, characterized in that It includes the following steps: 1) Connect the positive and negative poles of the DC side of the IGBT module 3 of the energy storage inverter 1 to the positive and negative poles of the capacitor bank 4 of the energy storage unit 2 respectively through two power cables 9. The detection circuit board 5 inside the capacitor bank 4 is signal-connected to the upper computer 7 through the communication module 6. The energy storage inverter 1 and the energy storage unit 2 are respectively reliably connected to the reference ground through cables. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7; 2) Arrange another identical detection circuit board 5 in the external exposed space. Its electrical connection is the same as that of the detection circuit board 5 inside the capacitor bank 4. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7 to judge whether the signals are abnormal; 3) Stop the clock work of the detection circuit board 5 inside the capacitor bank 4 through software. When the IGBT module 3 works, view the detected voltage and temperature signals through the upper computer 7 to judge whether the signals are abnormal; 4) Start the IGBT module 3, measure the voltage signals of the positive and negative poles of its DC side, and check whether the differential mode voltage is stable and whether the voltages of the positive and negative poles to PE are stable; 5) Complete the positioning of the electromagnetic interference generation.

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