A DC power distribution system stability system

Abstract

The present invention discloses a DC power distribution system stability system, including a harmonic current injection device, a voltage and current measurement module, an impedance calculation module, a plotting module, a deep reinforcement learning decision-making module, and a stability enhancer; the harmonic current injection device is connected to the DC bus; the voltage and current measurement module is connected to the DC bus; the impedance calculation module is connected to the voltage and current measurement module; the plotting module is connected to the impedance calculation module; the deep reinforcement learning decision-making module is connected to the plotting module; the stability enhancer is respectively connected to the deep reinforcement learning decision-making module and the DC bus. The DC power distribution system stability system provided by the embodiments of the present invention can flexibly regulate the impedance characteristics of the system and achieve the stable operation of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and particularly to a DC distribution system stability system. Background Art

[0002] DC distribution technology refers to the power transmission technology that uses DC system as the dominant in the distribution network. Compared with AC distribution technology, DC distribution technology has many potential advantages. However, similar to the AC distribution system, when there is a mismatch relationship among the equivalent impedance of the power source, the equivalent impedance of the load, and the equivalent impedance of the transmission line in the DC power supply system, the power supply system may become unstable, seriously affecting the working characteristics of the system. The existing impedance-based stability criterion can judge whether the DC distribution system is stable, but it cannot directly guide the real-time online adjustment of the impedance stabilizer. Summary of the Invention

[0003] The present invention provides a DC distribution system stability system to solve the deficiencies of the prior art.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A DC distribution system stability system includes a harmonic current injection device, a voltage and current measurement module, an impedance calculation module, a plotting module, a deep reinforcement learning decision module, and a stability enhancer;

[0006] The harmonic current injection device is connected to the DC bus and is used to inject harmonic current into the DC bus in a swept frequency manner;

[0007] The voltage and current measurement module is connected to the DC bus and is used to measure the harmonic current generated by the harmonic current injection device and the harmonic voltage at the power source side port and the harmonic voltage at the load side port caused by the harmonic current;

[0008] The impedance calculation module is connected to the voltage and current measurement module and is used to calculate the power source side port impedance and the load side port impedance according to the harmonic current at different frequencies measured by the voltage and current measurement module and the harmonic voltage at the power source side port and the harmonic voltage at the load side port under the action of the harmonic current;

[0009] The plotting module is connected to the impedance calculation module and is used to respectively draw the power source side port impedance Bode plot and the load side port impedance Bode plot by using the calculated power source side port impedance and load side port impedance at each frequency;

[0010] The deep reinforcement learning decision module is connected to the plotting module and is used to decide whether to output an impedance adjustment instruction to the stability enhancer according to the power source side port impedance Bode plot and the load side port impedance Bode plot;

[0011] The stability enhancer is respectively connected to the deep reinforcement learning decision module and the DC bus, and is used to adjust the impedance of the DC bus after receiving the impedance adjustment instruction.

[0012] Furthermore, the DC power distribution system stability system further includes an energy storage unit;

[0013] The energy storage unit is connected to the stability enhancer, and the deep reinforcement learning decision module is also connected to the DC bus;

[0014] The deep reinforcement learning decision module is also used to measure the voltage of the DC bus and determine whether to output a voltage adjustment instruction to the stability enhancer according to the voltage of the DC bus;

[0015] The stability enhancer is also used to control the energy storage unit to adjust the voltage of the DC bus after receiving the voltage adjustment instruction.

[0016] Furthermore, in the DC power distribution system stability system, the stability enhancer includes an H-bridge inverter. The DC side of the H-bridge inverter is connected to the deep reinforcement learning decision module through a capacitor, and the AC side of the H-bridge inverter is connected to the DC bus through an inductor and a switch.

[0017] Furthermore, in the DC power distribution system stability system, the frequency of the harmonic current injected by the harmonic current injection device is 10 Hz to 10 kHz.

[0018] Furthermore, in the DC power distribution system stability system, a timer for triggering the harmonic current injection device to periodically output harmonic current is provided in the harmonic current injection device.

[0019] Furthermore, in the DC power distribution system stability system, the deep reinforcement learning decision module adopts a deep deterministic policy gradient framework.

[0020] A DC power distribution system stability system provided by an embodiment of the present invention can flexibly regulate the impedance characteristics of the system and achieve stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1It is a schematic structural diagram of a DC power distribution system stability system provided by an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of harmonic current injection in an embodiment of the present invention.

[0024] Reference numerals:

[0025] Harmonic current injection device 1, voltage and current measurement module 2, impedance calculation module 3, drawing module 4, deep reinforcement learning decision module 5, stability enhancer 6, energy storage unit 7. Detailed implementation manners

[0026] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be understood that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component.

[0028] In addition, terms such as "long", "short", "inner", "outer", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or component referred to must have this specific orientation or be constructed and operated in this specific orientation, so it should not be construed as a limitation of the present invention.

[0029] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and through specific implementation manners.

[0030] Embodiment 1

[0031] Please refer to Figures 1-2 , an embodiment of the present invention provides a DC power distribution system stability system, including a harmonic current injection device 1, a voltage and current measurement module 2, an impedance calculation module 3, a drawing module 4, a deep reinforcement learning decision module 5, and a stability enhancer 6;

[0032] The harmonic current injection device 1 is connected to the DC bus and is used to inject harmonic current into the DC bus in a frequency-sweeping manner;

[0033] The voltage and current measurement module 2 is connected to the DC bus, and is used to measure the harmonic current generated by the harmonic current injection device 1 and the harmonic voltage at the power supply side port and the harmonic voltage at the load side port caused by the harmonic current;

[0034] The impedance calculation module 3 is connected to the voltage and current measurement module 2, and is used to calculate the power supply side port impedance and the load side port impedance according to the harmonic currents of different frequencies measured by the voltage and current measurement module 2 and the harmonic voltage at the power supply side port and the harmonic voltage at the load side port under the action of the harmonic current;

[0035] The plotting module 4 is connected to the impedance calculation module 3, and is used to respectively plot the Bode plot of the power supply side port impedance and the Bode plot of the load side port impedance by using the calculated power supply side port impedance and load side port impedance at each frequency;

[0036] The deep reinforcement learning decision module 5 is connected to the plotting module 4, and is used to decide whether to output an impedance adjustment instruction to the stability enhancer 6 according to the Bode plot of the power supply side port impedance and the Bode plot of the load side port impedance;

[0037] The stability enhancer 6 is respectively connected to the deep reinforcement learning decision module 5 and the DC bus, and is used to adjust the impedance of the DC bus after receiving the impedance adjustment instruction.

[0038] Preferably, the DC distribution system stability system further includes an energy storage unit 7;

[0039] The energy storage unit 7 is connected to the stability enhancer 6, and the deep reinforcement learning decision module 5 is also connected to the DC bus;

[0040] The deep reinforcement learning decision module 5 is also used to measure the voltage of the DC bus, and decide whether to output a voltage adjustment instruction to the stability enhancer 6 according to the voltage of the DC bus;

[0041] When the voltage of the DC bus fluctuates due to the power fluctuation of the new energy power generation equipment, the stability enhancer 6 is also used to control the energy storage unit 7 to adjust the voltage of the DC bus after receiving the voltage adjustment instruction.

[0042] Preferably, in the DC distribution system stability system, the stability enhancer 6 includes an H-bridge inverter. The DC side of the H-bridge inverter is connected to the deep reinforcement learning decision module 5 through a capacitor, and the AC side of the H-bridge inverter is connected to the DC bus through an inductor and a switch.

[0043] Preferably, in the DC distribution system stability system, the frequency of the harmonic current output by the harmonic current injection device 1 is 10 Hz to 10 kHz.

[0044] Preferably, in the DC power distribution system stability system, a timer for triggering the harmonic current injection device 1 to periodically output harmonic current is provided in the harmonic current injection device 1.

[0045] Preferably, in the DC power distribution system stability system, the deep reinforcement learning decision-making module 5 adopts a deep deterministic policy gradient framework.

[0046] A DC power distribution system stability system provided by an embodiment of the present invention can flexibly regulate the impedance characteristics of the system and achieve stable operation of the system.

[0047] So far, the above-described embodiments have been described for purposes of illustration and description. It is not intended to be exhaustive or limit the disclosure. Individual elements or features of a particular embodiment are generally not limited by the particular embodiment, but when applicable, they can be interchanged and used in selected embodiments even if not specifically shown or described. In many respects, the same elements or features can also be changed. Such changes are not considered to deviate from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0048] Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. To thoroughly understand the embodiments of this disclosure, numerous details are set forth, such as examples of specific parts, devices, and methods. Obviously, for those skilled in the art, specific details are not required, and the example embodiments can be implemented in many different forms, and neither should be construed as limiting the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0049] Here, specific technical terms are used only for the purpose of describing specific example embodiments and are not intended for purposes of limitation. Unless the context clearly dictates otherwise, the singular forms "a" and "the" used herein may also be intended to include the plural forms. The terms "comprising" and "having" mean including, and thus specify the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or additional presence of one or more other features, wholes, steps, operations, elements, components, and / or combinations thereof. Unless explicitly indicated the order of execution, the method steps, processes, and operations described herein are not to be construed as necessarily requiring to be executed in the specific order discussed and shown. It should also be understood that additional or alternative steps can be employed.

[0050] When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it can be directly on, engaged to, connected to or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element or layer is referred to as being "directly on", "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, intervening elements or layers may not be present. Other words used to describe the relationship of elements should be interpreted in a similar manner (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.). The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Although terms such as first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or portions, these elements, components, regions, layers and / or portions are not limited by these terms. These terms may only be used to distinguish one element, component, region or portion from another. Unless clearly indicated by the context, terms such as "first", "second" and other numerical terms used herein do not imply a sequence or order. Thus, a first element, component, region, layer or portion discussed below may be referred to as a second element, component, region, layer or portion without departing from the teachings of the exemplary embodiment.

[0051] Spatial relative terms, such as "inner", "outer", "beneath", "below", "lower", "above", "upper", etc., may be used herein for ease of description to describe the relationship between one element or feature and another element or feature shown in the figures. Spatial relative terms may mean different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "beneath" or "below" another element or feature will be oriented "above" the other element or feature. Thus, the exemplary term "below" can include both an upward and a downward orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and interpreted in terms of the spatial relative descriptions herein.

Claims

1. A DC power distribution system stability system, characterized in that, It includes a harmonic current injection device, a voltage and current measurement module, an impedance calculation module, a plotting module, a deep reinforcement learning decision module, and a stability enhancer; The harmonic current injection device is connected to the DC bus and is used to inject harmonic current into the DC bus in a frequency-sweeping manner; The voltage and current measurement module is connected to the DC bus and is used to measure the harmonic current generated by the harmonic current injection device and the harmonic voltage at the power supply side port and the harmonic voltage at the load side port caused by the harmonic current; The impedance calculation module is connected to the voltage and current measurement module and is used to calculate the power supply side port impedance and the load side port impedance according to the harmonic current of different frequencies measured by the voltage and current measurement module and the harmonic voltage at the power supply side port and the harmonic voltage at the load side port under the action of the harmonic current; The plotting module is connected to the impedance calculation module and is used to draw the power supply side port impedance Bode plot and the load side port impedance Bode plot respectively using the calculated power supply side port impedance and load side port impedance of each frequency; The deep reinforcement learning decision module is connected to the plotting module and is used to decide whether to output an impedance adjustment instruction to the stability enhancer according to the power supply side port impedance Bode plot and the load side port impedance Bode plot; The stability enhancer is respectively connected to the deep reinforcement learning decision module and the DC bus and is used to adjust the impedance of the DC bus after receiving the impedance adjustment instruction.

2. The DC power distribution system stability system according to claim 1, characterized in that It also includes an energy storage unit; The energy storage unit is connected to the stability enhancer, and the deep reinforcement learning decision module is also connected to the DC bus; The deep reinforcement learning decision module is also used to measure the voltage of the DC bus and decide whether to output a voltage adjustment instruction to the stability enhancer according to the voltage of the DC bus; The stability enhancer is also used to control the energy storage unit to adjust the voltage of the DC bus after receiving the voltage adjustment instruction.

3. The DC power distribution system stability system according to claim 2, wherein The stability enhancer includes an H-bridge inverter. The DC side of the H-bridge inverter is connected to the deep reinforcement learning decision module through a capacitor, and the AC side of the H-bridge inverter is connected to the DC bus through an inductor and a switch.

4. The DC power distribution system stability system according to claim 1, characterized in that The frequency of the harmonic current output by the harmonic current injection device is 10 Hz to 10 kHz.

5. The DC power distribution system stability system according to claim 1, characterized in that, A timer for triggering the harmonic current injection device to output harmonic current regularly is provided in the harmonic current injection device.

6. The DC power distribution system stability system according to claim 1, wherein The deep reinforcement learning decision module adopts a deep deterministic policy gradient framework.

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