Common-mode current and common-mode voltage suppression circuit of energy storage converter

Abstract

The utility model relates to the technical field of power supply circuits, and particularly discloses a suppression circuit for common-mode current and common-mode voltage of an energy storage converter. A grounding capacitor and an alternating-current side filter capacitor are arranged on an alternating-current side filter, the alternating-current side filter capacitor is arranged between the alternating-current side filter and the grounding capacitor, and a neutral-line inductor is connected in series between a direct-current side bus capacitor and the alternating-current side filter capacitor. One end of the neutral-line inductor is arranged between the side filter capacitor and the grounding capacitor, and the other end of the neutral-line inductor is arranged on the direct-current side bus support capacitor to form a common-mode backflow channel; the direct-current side and the alternating-current side are connected through the neutral-line inductor to form a common-mode current backflow path, the situation that common-mode current flows into the power grid side is reduced, a common-mode low-pass filtering path in the system is provided for the common-mode current, the common-mode current can be effectively restrained through the neutral-line inductor, and therefore common-mode voltage and the common-mode current are restrained; and the stability and reliability of the circuit are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, in particular to a suppression circuit for common mode current and common mode voltage of an energy storage converter. Background Art

[0002] With the vigorous development of the new energy and energy storage industries, semiconductor switching devices (such as IGBT, MOSFET, SIC, etc.) are usually used in high-power equipment such as energy storage converters to form the main power conversion circuit. The switching devices are controlled by software wave programs to open and close, so as to achieve DC / AC conversion of electric energy; however, the switching devices will generate large common-mode interference to the ground during the high-frequency opening and closing process, resulting in large common-mode current and common-mode voltage in the power electronic converter. For high-power and high-frequency controlled converters, the common-mode interference is more serious.

[0003] In the prior art, reference Figure 1 The common-mode voltage and common-mode current suppression circuit includes an AC / DC power module 11, an AC-side filter 3 having a first AC-side filter capacitor 2, and a DC-side support capacitor 4. An industrial frequency isolation transformer is configured on the AC side to isolate the influence of the common-mode voltage on the AC side. Due to the large size, heavy weight, and high cost of the industrial frequency isolation transformer, the application scope of the scheme is limited. Moreover, although configuring an isolation transformer on the AC side can suppress the influence of the common-mode voltage on the AC side, it cannot suppress the common-mode voltage on the DC side very well, affecting the stability of the circuit. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a common-mode current and common-mode voltage suppression circuit for an energy storage converter, so as to simultaneously reduce the common-mode voltage and common-mode current of the circuit and improve the stability of the circuit.

[0005] The technical solution adopted by the utility model is:

[0006] A suppression circuit for common mode current and common mode voltage of an energy storage converter comprises an AC / DC power module, an AC side filter arranged on the AC side of the AC / DC power module, a DC side bus support capacitor arranged on the DC side of the AC / DC power module, a grounding capacitor and an AC side filter capacitor arranged on the AC side filter, the AC side filter capacitor being arranged between the AC side filter and the grounding capacitor, a neutral line inductor being connected in series between the DC side bus capacitor and the AC side filter capacitor, one end of the neutral line inductor being arranged between the DC side filter capacitor and the grounding capacitor, and the other end of the neutral line inductor being arranged on the DC side bus support capacitor to form a common mode return path.

[0007] The grid-side transformer isolates the AC end of the equipment from the grid side to reduce interference to the grid side. The DC side and the AC side are connected through the neutral line inductor to form a common-mode current return path, providing a common-mode low-pass filter path within the system for the common-mode current. The neutral line inductor suppresses the high-frequency common-mode current caused by the switching of the power tube, suppresses the common-mode current on the neutral line inductor, and prevents the common-mode interference from affecting the grid equipment externally; the DC side common-mode inductor suppresses the DC side common-mode interference. Because the DC side energy storage battery or photovoltaic panel has a large junction capacitance to the ground, adding the DC side common-mode inductor can suppress the common mode to the ground. interference , improving the stability and reliability of the system.

[0008] Optionally, the neutral line inductor is connected in series between a midpoint of the AC side filter capacitor and the grounding capacitor and a virtual center point of the DC side busbar support capacitor.

[0009] Optionally, the AC side filter is in the form of an LCL filter, which includes an AC filter inductor L2 and a grid-side transformer L4, one end of the AC side filter capacitor C2 is connected to the wire between the AC filter inductor L2 and the grid-side transformer L4, and the other end of the AC side filter capacitor C2 is connected to the grounding capacitor C3.

[0010] Optionally, the AC side filters are respectively arranged on three-phase AC lines, and the AC side filter capacitor C2 is respectively connected to each AC side filter.

[0011] Optionally, a DC side common-mode inductor L1 is provided on each phase circuit on the DC side of the AC / DC power module, and the DC side bus support capacitor C1 is provided between the DC side common-mode inductor L1 and the AC / DC power module, and both ends of the DC side bus support capacitor C1 are respectively connected to the positive and negative poles of the DC line.

[0012] The beneficial effects of the utility model are as follows: the DC side and the AC side are connected through the neutral line inductor to form a common-mode current return path, which reduces the common-mode current flowing into the grid side, provides a common-mode low-pass filter path within the system for the common-mode current, and the common-mode current can be effectively suppressed by the neutral line inductor, thereby suppressing the common-mode voltage and common-mode current, and improving the stability and reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the background technology;

[0014] Figure 2 It is a schematic diagram of the overall structure of the utility model.

[0015] The numbers and names in the figure correspond to each other as follows: L1, DC side common mode inductor; C1, DC side bus support capacitor; A1, DC / AC power module; L2, AC filter inductor; L4, grid side transformer; C2, AC side filter capacitor; L3, neutral line inductor; C3, grounding capacitor. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] See also Figure 1-2 , the utility model provides a technical solution:

[0018] A common-mode current and common-mode voltage suppression circuit for an energy storage converter comprises an AC / DC power module A1, an AC-side filter arranged on the AC side of the AC / DC power module A1, a DC-side busbar support capacitor C1 arranged on the DC side of the AC / DC power module A1, a DC-side common-mode inductor L1 is arranged on each phase circuit on the DC side of the AC / DC power module A1, the DC-side common-mode inductor L1 can suppress DC-side common-mode interference, the DC-side busbar support capacitor C1 is arranged between the DC-side common-mode inductor L1 and the AC / DC power module A1, two ends of the DC-side busbar support capacitor C1 are respectively connected to the positive and negative poles of a DC line, a grounding capacitor C3 and an AC-side filter capacitor C2 are arranged on the AC-side filter, the AC-side filter capacitor C2 is arranged between the AC-side filter and the grounding capacitor C3, and the AC-side filter capacitor C2 is directly connected to the AC-side filter.

[0019] A neutral inductor L3 is connected in series between the DC side bus support capacitor C1 and the AC side filter capacitor C2. One end of the neutral inductor L3 is arranged between the AC side filter capacitor and the grounding capacitor C3. The other end of the neutral inductor L3 is arranged on the DC side bus support capacitor C1 to form a common-mode return path. The neutral inductor L3 is connected in series between the midpoint of the AC side filter capacitor C2 and the grounding capacitor C3 and the virtual center point of the DC side bus support capacitor C1. The neutral inductor L3 can suppress high-frequency common-mode current so that the common-mode interference does not affect the grid-side equipment externally.

[0020] The AC side filter is in the form of an LCL filter, and the AC side filter includes an AC filter inductor L2 and a grid side transformer L4, one end of the AC side filter capacitor C2 is connected to the wire between the AC filter inductor L2 and the grid side transformer L4, and the other end of the AC side filter capacitor C2 is connected to the grounding capacitor C3. The AC side filters are respectively arranged on the three-phase AC lines, and the AC side filter capacitor C2 is respectively connected to each AC side filter.

[0021] Finally, it should be noted that the above are only preferred examples of the utility model and are not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A common mode current and common mode voltage suppression circuit for an energy storage converter, comprising an AC / DC power module A1, an AC side filter arranged on the AC side of the AC / DC power module A1, and a DC side busbar support capacitor C1 arranged on the DC side of the AC / DC power module A1, characterized in that: The AC side filter is provided with a grounding capacitor C3 and an AC side filter capacitor C2, the AC side filter capacitor C2 is arranged between the AC side filter and the grounding capacitor C3, a neutral line inductor L3 is connected in series between the DC side bus support capacitor C1 and the AC side filter capacitor C2, one end of the neutral line inductor L3 is arranged between the AC side filter capacitor and the grounding capacitor C3, and the other end of the neutral line inductor L3 is arranged on the DC side bus support capacitor C1 to form a common mode return path.

2. The common mode current and common mode voltage suppression circuit of an energy storage converter according to claim 1, characterized in that: The neutral line inductor L3 is connected in series between the midpoint of the AC side filter capacitor C2 and the grounding capacitor C3 and the virtual center point of the DC side busbar support capacitor C1.

3. The circuit for suppressing common mode current and common mode voltage of an energy storage converter according to claim 1, characterized in that: The AC side filter is in the form of an LCL filter, and the AC side filter includes an AC filter inductor L2 and a grid side transformer L4. One end of the AC side filter capacitor C2 is connected to the wire between the AC filter inductor L2 and the grid side transformer L4, and the other end of the AC side filter capacitor C2 is connected to the grounding capacitor C3.

4. The circuit for suppressing common mode current and common mode voltage of an energy storage converter according to claim 1, characterized in that: The AC side filters are respectively arranged on the three-phase AC lines, and the AC side filter capacitor C2 is respectively connected to each AC side filter.

5. The circuit for suppressing common mode current and common mode voltage of an energy storage converter according to claim 1, characterized in that: A DC side common-mode inductor L1 is provided on each phase circuit of the DC side of the AC / DC power module A1, and the DC side busbar support capacitor C1 is provided between the DC side common-mode inductor L1 and the AC / DC power module A1, and both ends of the DC side busbar support capacitor C1 are respectively connected to the positive and negative poles of the DC line.

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