A dc filter capacitor action regulating device and method

Abstract

This invention discloses a device and method for adjusting the effect of a DC filter capacitor, relating to the field of electronic device technology. The device includes a current regulator and a dual-winding inductor. The dual-winding inductor includes an iron core, a working winding, and a control winding, with both the working and control windings mounted on the iron core. The control winding is connected in series with the current regulator. The working winding is connected in series with the filter capacitor to form a capacitor-inductance branch. The capacitor-inductance branch and the load are connected in parallel across a DC power supply. The current regulator is positioned between the DC power supply and the load. The current regulator samples the current in the branch containing the load and adjusts the DC current in the control winding based on the sampled branch current, thereby changing the inductance value of the working winding. This invention achieves the adjustment of the effect of a DC filter capacitor.

Description

Technical Field

[0001] This invention relates to the field of electronic device technology, and in particular to a DC filter capacitor adjustment device and method. Background Technology

[0002] DC distribution networks have numerous connection points, and any non-ideal conditions at these connection points can lead to various power quality problems. Among these, ripple, with its diverse causes and widespread impact, is one of the major power quality issues in DC distribution networks. Ripple not only affects the stability of the DC bus voltage but also the power quality of the grid; severe high-frequency ripple can even jeopardize the safe and stable operation of the system. To address this problem, filter capacitors (such as...) are typically connected in parallel at the DC bus. Figure 1 As shown, the DC bus capacitor absorbs high-frequency ripple from the bus voltage to limit the high-frequency ripple component of the output voltage. The DC bus capacitor effectively mitigates transient power fluctuations in the DC system and suppresses voltage fluctuations. When the rectified voltage is higher than the capacitor voltage, the capacitor charges; when the rectified voltage is lower than the capacitor voltage, the capacitor discharges. During the charging and discharging process, the output voltage remains relatively stable, thereby improving system stability and power quality. Therefore, the filter capacitor is an indispensable component in the system.

[0003] Filter capacitors do effectively solve ripple problems and improve system stability and power quality. However, when a DC line experiences an inter-electrode short circuit, the energy stored in the filter capacitor is rapidly released to the short-circuit point, with the discharge current reaching thousands to tens of thousands of amperes, causing transient current surges. Generally, the filter capacitor's capacitance is matched to the system's rated power. Under light load conditions, the surge current released by the capacitor is relatively larger than under heavy load conditions when a short-circuit fault occurs, which could potentially damage the capacitor or other electrical components. Therefore, a method is needed to balance ripple suppression and prevention of short-circuit fault surge currents. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for adjusting the function of a DC filter capacitor, thereby achieving adjustment of the function of the DC filter capacitor.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A DC filter capacitor function adjustment device is provided, which operates on a DC filter circuit, the DC filter circuit including a DC power supply, a load and a filter capacitor, and the DC filter capacitor function adjustment device including a current regulator and a dual-winding inductor.

[0007] The dual-winding inductor includes an iron core, a working winding, and a control winding, with both the working winding and the control winding disposed on the iron core; the control winding is connected in series with the current regulator; the working winding is connected in series with the filter capacitor to form a capacitor-inductance branch; the capacitor-inductance branch and the load are both connected in parallel across the DC power supply.

[0008] The current regulator is disposed between the DC power supply and the load. The current regulator is used to sample the current of the branch where the load is located, and adjust the magnitude of the DC current in the control winding according to the sampled branch current, thereby changing the inductance value of the working winding.

[0009] A method for adjusting the function of a DC filter capacitor, applied to a DC filter capacitor function adjustment device, the adjustment method comprising:

[0010] The current in the branch where the load is located is sampled by the current regulator;

[0011] Based on the sampled branch current, the DC current of the control winding in the dual-winding inductor is adjusted, thereby changing the inductance value of the working winding in the dual-winding inductor.

[0012] Optionally, based on the sampled branch current, the DC current of the control winding in the dual-winding inductor is adjusted, thereby changing the inductance value of the working winding in the dual-winding inductor. Specifically, this includes:

[0013] If the sampled branch current is within the preset small current threshold range, then based on the first preset current conversion formula, the DC current of the control winding in the dual-winding inductor is increased to reduce the inductance value of the working winding.

[0014] If the sampled branch current is within the preset high current threshold range, then based on the second preset current conversion formula, the DC current of the control winding in the dual-winding inductor is reduced to increase the inductance value of the working winding.

[0015] Optionally, the first preset current conversion formula is a linear function or a step function.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0017] This invention discloses a DC filter capacitor adjustment device and method, which includes a current regulator and a dual-winding inductor. The dual-winding inductor comprises an iron core, a working winding, and a control winding. The working winding is connected in series with the filter capacitor, serving to adjust the function of the filter capacitor. The current regulator samples the current in the branch containing the load, and adjusts the DC current in the control winding based on the sampled branch current, thereby changing the inductance value of the working winding. This invention analyzes the load size by sampling the input current and feeding it back to the regulator, and then controls the DC current passing through the bias coil to adjust the working inductance value. It utilizes an adjustable filter inductor to solve the problem of inrush current hazards during sudden short-circuit faults and also addresses the issue of configuring the inductance value according to different loads. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a DC filter circuit in the prior art;

[0020] Figure 2 This is a schematic diagram of the DC filter capacitor function adjustment device of the present invention;

[0021] Figure 3 This is a flowchart illustrating the DC filter capacitor adjustment method of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of a specific example of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a DC filter capacitor function adjustment device and method, in which an inductor is connected in series at the filter capacitor branch of the DC power supply system, and the inductor value is actively adjusted according to the load size to suppress the inrush current during short circuit faults and protect circuit components.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] like Figure 2 As shown, this embodiment provides a DC filter capacitor adjustment device, which acts on a DC filter circuit, the DC filter circuit including a DC power supply (corresponding to...). Figure 2 The DC filter capacitor adjustment device includes a current regulator (corresponding to the input terminal), load, and filter capacitor C. Figure 2 (Regulator) and dual-winding inductor.

[0028] The dual-winding inductor includes an iron core, a working winding L1, and a control winding L2, with both the working winding L1 and the control winding L2 disposed on the iron core. The working winding L1 and the control winding L2 are conjugate. The control winding L2 is connected in series with the current regulator. The working winding L2 is connected in series with the filter capacitor C to form a capacitor-inductance branch. The capacitor-inductance branch and the load are both connected in parallel across the DC power supply.

[0029] The current regulator is disposed between the DC power supply and the load. The current regulator is used to sample the current of the branch where the load is located, and adjust the DC current in the control winding L2 according to the sampled branch current, thereby changing the inductance value of the working winding L1.

[0030] Example 2

[0031] like Figure 3 As shown, this embodiment also provides a method for adjusting the function of a DC filter capacitor, applied to the DC filter capacitor adjustment device in Embodiment 1. The adjustment method includes:

[0032] Step 100: Sample the current of the branch where the load is located using a current regulator.

[0033] Step 200: Based on the sampled branch current, adjust the DC current of the control winding in the dual-winding inductor, thereby changing the inductance value of the working winding in the dual-winding inductor. Specifically, the current regulator outputs a DC current value I2 to the control winding in the dual-winding inductor based on the sampled branch current I1; then, it changes the equivalent inductance of the working winding by changing the saturation degree of the iron core using the saturation inductance method.

[0034] The saturation inductance method refers to an inductor with two windings on its core: a working winding that carries alternating current (AC) and a control winding that carries direct current (DC). By changing the magnitude of the DC current in the control winding, the saturation level of the core is altered, thereby changing the inductance of the working winding. When the inductance is saturated, the permeability μ decreases significantly, ultimately leading to a substantial reduction in inductance and loss of the ability to suppress current.

[0035] Step 200 specifically includes:

[0036] 1) If the sampled branch current is within the preset small current threshold range, then based on the first preset current conversion formula, the DC current of the control winding in the dual-winding inductor is increased to reduce the inductance value of the working winding; that is, when the load is large, the current regulator samples a small current I1, and at this time the output DC current value I2 is increased, thereby reducing the inductance value of the working winding, and the impact current suppression under short circuit conditions is achieved within a reasonable range.

[0037] 2) If the sampled branch current is within the preset high current threshold range, then based on the second preset current conversion formula, the DC current of the control winding in the dual-winding inductor is reduced to increase the inductance value of the working winding. That is, when the load is small, the current regulator samples a large current I1, and at this time, the output DC current value I2 is reduced, thereby increasing the inductance value of the working winding and enhancing the suppression effect of the adjustable inductor on the inrush current when a short-circuit fault occurs.

[0038] Generally, I1 and I2 do not have fixed corresponding function formulas. I2 is generated based on the value of I1 fed back to the regulator to adjust for the current load. In a specific embodiment, a first preset current conversion formula and a second preset current conversion formula can be set; the first preset current conversion formula is a linear function, such as I2 = k * I1; or a step function.

[0039] In one instance, such as Figure 4 As shown, a bidirectional Buck-Boost DC / DC converter supplies a constant power load of 4kW, with the DC bus stable at 400V. The power is increased by 1kW at 1s, 2s, and 3s respectively. When the load increases to 5kW, it exceeds the power threshold. At this point, a short-circuit fault could cause a dangerous inrush current, requiring adjustment of the inductance to suppress the inrush current. Manually modifying or adjusting components would be time-consuming and labor-intensive; however, the DC filter capacitor adjustment method described in this embodiment solves the configuration problem more efficiently.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0041] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A DC filter capacitor adjustment device, acting on a DC filter circuit, said DC filter circuit comprising a DC power supply, a load, and a filter capacitor, characterized in that, The DC filter capacitor function adjustment device includes a current regulator and a dual-winding inductor. The dual-winding inductor includes an iron core, a working winding, and a control winding, with both the working winding and the control winding disposed on the iron core; the control winding is connected in series with the current regulator; the working winding is connected in series with the filter capacitor to form a capacitor-inductance branch; the capacitor-inductance branch and the load are both connected in parallel across the DC power supply. The current regulator is disposed between the DC power supply and the load. The current regulator is used to sample the current of the branch where the load is located, and adjust the magnitude of the DC current in the control winding according to the sampled branch current, thereby changing the inductance value of the working winding.

2. A method for adjusting the function of a DC filter capacitor, applied to the DC filter capacitor adjustment device according to claim 1, characterized in that, Adjustment methods include: The current in the branch where the load is located is sampled by the current regulator; Based on the sampled branch current, the DC current of the control winding in the dual-winding inductor is adjusted, thereby changing the inductance value of the working winding in the dual-winding inductor.

3. The method for adjusting the function of a DC filter capacitor according to claim 2, characterized in that, Based on the sampled branch current, the DC current of the control winding in the dual-winding inductor is adjusted, thereby changing the inductance value of the working winding in the dual-winding inductor. Specifically, this includes: If the sampled branch current is within the preset small current threshold range, then based on the first preset current conversion formula, the DC current of the control winding in the dual-winding inductor is increased to reduce the inductance value of the working winding. If the sampled branch current is within the preset high current threshold range, then based on the second preset current conversion formula, the DC current of the control winding in the dual-winding inductor is reduced to increase the inductance value of the working winding.

4. The method for adjusting the function of a DC filter capacitor according to claim 3, characterized in that, The first preset current conversion formula is a linear function or a step function.

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