Soft characteristic reactor

Abstract

The present application relates to the technical field of power electronic equipment. The purpose is to provide a soft characteristic reactor, the inductance of which decreases with the increase of current in a certain range to adapt to the elevator operation characteristics. A novel soft characteristic reactor structure comprises an upper yoke, a lower yoke and three coil-wound core columns; each core column comprises a first core and a second core made of silicon steel, the magnetic permeability of the first core is higher than that of the second core, and a plurality of air gaps are respectively arranged on the first core and the second core, and the coil is wound outside the assembled first core and second core to form the coil-wound core column; the upper yoke comprises a first upper yoke and a second upper yoke, and the lower yoke comprises a first lower yoke and a second lower yoke; the first upper yoke, the first lower yoke and the first core are made of the same silicon steel material, and the second upper yoke, the second lower yoke and the second core are made of the same silicon steel material.

Description

Technical Field

[0001] This invention relates to the field of power electronic equipment technology, and more specifically, to a soft-characteristic reactor. Background Technology

[0002] Most current elevator designs employ variable frequency speed control technology and use external high-power braking resistors to absorb braking energy, resulting in significant energy waste. However, by adopting emerging technologies such as fully digital PWM technology and bidirectional high-power DC / DC technology, the overall energy saving rate can reach over 30%. The rectifier / inverter filter reactor, as one of the main components in the elevator energy storage system, has a crucial impact on elevator energy saving and power grid quality.

[0003] The load rate of an elevator varies greatly during operation, which requires the reactor to have good filtering performance under both no-load and full-load conditions. Specifically, when the elevator is running under no-load conditions and the current is low, a larger inductance is required. When the elevator is running under full load conditions and the current is high, a smaller inductance is required. In other words, the inductance of the reactor must be within a certain range, decreasing as the current increases.

[0004] Developing reactors that meet the above requirements will allow elevator manufacturers to leverage their advantages of high performance and low energy consumption, thereby reducing elevator operating costs and generating significant economic benefits. Simultaneously, it can provide stable elevator power to various sectors of society, promoting the development of the elevator industry, improving people's quality of life, and better serving society. It will also help reduce the energy consumption of the elevator industry, further reduce carbon emissions, and create greater social benefits.

[0005] The inductance is directly proportional to (n^2 * S) and inversely proportional to (lfe / μfe + la / μa). Where n = number of turns in the coil, S = core cross-sectional area, lfe = length of the silicon steel magnetic circuit in the core, μfe = permeability of the core, la = air gap length in the core, and μa = permeability of the air gap. When the iron-core reactor is operating, the permeability of the core changes with the magnitude of the current. The permeability curve is non-linear, rising from low to high and then decreasing again.

[0006] The inductance characteristics of existing general iron-core reactors are similar in curve to... Figure 5 Inductance characteristic curve L1: Within a certain current range, the inductance remains basically unchanged; when the current increases to a certain range, because the magnetic flux density of the iron core enters the saturation range, its permeability decreases rapidly, and the inductance also decreases rapidly; then the magnetic flux density of the iron core is saturated, and the inductance of the reactor remains basically unchanged within a small range.

[0007] Therefore, existing iron-core reactors cannot be well matched with the operating characteristics of elevators, and the use of existing iron-core reactors limits elevator performance. Summary of the Invention

[0008] The purpose of this invention is to provide a soft-characteristic reactor that reduces its inductance as the current increases within a certain range to meet the needs of new applications, thus adapting to the operating characteristics of elevators.

[0009] Based on the inductive characteristics of iron-core reactors, this application proposes a novel soft-characteristic reactor structure, comprising: an upper yoke, a lower yoke, and three iron core columns wound with coils. Each iron core column includes: a first iron core and a second iron core made of silicon steel with different permeabilities, wherein the permeability of the first iron core is higher than that of the second iron core. The first iron core has multiple first air gaps, and the second iron core has multiple second air gaps. The first and second iron cores are assembled together to form the iron core column, and the coils are wound around the outside of the iron core columns to form the coil-wound iron core column. The winding method of the coils adopts conventional winding methods in the art, and the wiring also adopts conventional wiring methods in the art. The upper yoke includes a first upper yoke and a second upper yoke, and the lower yoke includes a first lower yoke and a second lower yoke. The first iron core is disposed between the first upper yoke and the first lower yoke, and the second iron core is disposed between the second upper yoke and the second lower yoke. The first upper yoke, the first lower yoke, and the first core are made of the same silicon steel material, except that no air gap is provided on the first upper yoke and the first lower yoke; the second upper yoke, the second lower yoke, and the second core are made of the same silicon steel material, except that no air gap is provided on the second upper yoke and the second lower yoke.

[0010] Silicon steel includes oriented silicon steel and non-oriented silicon steel. Different types of silicon steel have different magnetic permeabilities. When assembling the core column, different materials can be selected to make the first and second cores according to actual application requirements. The selection of materials should ensure that the magnetic permeability of the first core is higher than that of the second core. For example: both the first and second cores can be made of oriented silicon steel; both can be made of non-oriented silicon steel; the first core can be made of oriented silicon steel, and the second core can be made of non-oriented silicon steel; or even the first core can be made of non-oriented silicon steel, and the second core can be made of oriented silicon steel.

[0011] During elevator operation, the total inductance of the soft-characteristic reactor is the sum of the inductance of the first iron core and the inductance of the second iron core. The total inductance of the soft-characteristic reactor gradually decreases in approximately five stages.

[0012] First stage: When the load is small and the current flowing through the soft characteristic reactor is also small, the inductance in the first core and the second core remains basically unchanged, and the total inductance of the reactor also remains basically unchanged.

[0013] Second stage: As the load continues to increase, the current through the reactor also increases. The magnetic flux density of the first iron core approaches saturation, its permeability gradually decreases, and the inductance gradually decreases to a relatively small value. During this stage, the inductance in the second iron core remains essentially unchanged. At this time, the total inductance also decreases accordingly.

[0014] The third stage: As the current continues to increase, the magnetic flux density of the first iron core reaches saturation, and its inductance remains relatively constant within a small range. The inductance of the second iron core also remains essentially constant. Therefore, the total inductance of the reactor also remains roughly constant during this stage.

[0015] Fourth stage: As the current continues to increase, the inductance in the first iron core remains unchanged. At this time, the magnetic flux density of the second iron core enters the saturation range, its permeability gradually decreases, and its inductance gradually decreases. The total inductance also gradually decreases.

[0016] Fifth stage: The elevator load continues to increase until it reaches full load. At this point, the current also continues to increase. The magnetic flux density of both the first and second iron cores is saturated, and the inductance in both cores remains essentially constant. Therefore, the total inductance of the reactor also remains approximately constant during this stage.

[0017] After the above five stages, as the elevator load increases, the total inductance of the reactor changes in a near-step manner from large to small as the current increases. This adapts well to the elevator's operating characteristics and facilitates optimal elevator performance. In practical applications, the required inductance curve can be achieved by adjusting the cross-sectional areas of the first and second cores and the total air gap length, based on the permeability characteristics of two different silicon steels, when designing the soft-characteristic reactor described in this invention, according to the specific elevator load characteristics. Attached Figure Description

[0018] Other advantages and features of the invention are illustrated by the following description of embodiments of the invention in conjunction with the accompanying drawings. These embodiments are given by way of example but are not intended to limit the invention.

[0019] Figure 1 This is a front structural schematic diagram of a preferred embodiment of the soft-characteristic reactor of the present invention.

[0020] Figure 2 for Figure 1A side view of the embodiment shown.

[0021] Figure 3 for Figure 1 The diagram shows a front cross-sectional view of the embodiment.

[0022] Figure 4 for Figure 1 A schematic diagram of the side cross-sectional structure of the iron core column in the embodiment shown.

[0023] Figure 5 for Figure 1 The illustrated embodiment shows the inductance characteristic curves during operation; curve L shows the change in inductance of the soft-characteristic reactor with the change of current during operation, curve L1 shows the change in inductance of the first iron core in the soft-characteristic reactor with the change of current during reactor operation, and curve L2 shows the change in inductance of the second iron core in the soft-characteristic reactor with the change of current during reactor operation. Detailed Implementation

[0024] The soft-characteristic reactor structure shown in the figure includes: an upper yoke 1, a lower yoke 3, and three iron core columns 2 wound with coils 4.

[0025] Combined with the diagram Figure 2 and Figure 4 As shown, each core post 2 is formed by assembling a first core 21 and a second core 22 together, with the coil 4 wound around the outside of the assembled structure of the first core 21 and the second core 22. The winding method of the coil 4 adopts the conventional winding method in the art, and the wiring also adopts the conventional wiring method in the art, which will not be described in detail here. The upper yoke 1 includes a first upper yoke 11 and a second upper yoke 12, and the lower yoke 3 includes a first lower yoke 31 and a second lower yoke 32. The first core 21 is located between the first upper yoke 11 and the first lower yoke 31, and the second core 22 is located between the second upper yoke 12 and the second lower yoke 32. The first upper yoke 11, the first core 21, and the first lower yoke 31 are made of the same silicon steel material, and the second upper yoke 12, the second core 22, and the second lower yoke 32 are also made of the same silicon steel material.

[0026] In this embodiment, the first core 21 is made of grain-oriented silicon steel and has multiple first air gaps 210 thereon; the second core 22 is made of non-grain-oriented silicon steel and has multiple second air gaps 220 thereon. The permeability of the grain-oriented silicon steel used is higher than that of the non-grain-oriented silicon steel used, so that the permeability of the first core 21 is higher than that of the second core 22.

[0027] During elevator operation, as the elevator load increases, the current through the reactor also increases. The total inductance (curve L) in the reactor is the sum of the inductance in the first core 21 (curve L1) and the inductance in the second core 22 (curve L2). For example... Figure 5 As shown, the total inductance in the reactor decreases gradually in roughly five stages:

[0028] Phase 1: When the load is small and the current is in the range of approximately less than 10A, the inductance in the first core 21 and the second core 22 remains basically unchanged, and the total inductance of the corresponding reactor also remains basically unchanged.

[0029] Second stage: As the load continues to increase, the current through the reactor also increases. When the current is in the range of approximately 10-11A, the magnetic flux density of the first iron core 21 enters the saturation range, its permeability gradually decreases, and the inductance gradually decreases to a relatively small value. During this stage, the inductance in the second iron core 22 remains basically unchanged. At this time, the total inductance also decreases accordingly.

[0030] In the third stage, as the current continues to increase and reaches approximately 11-16A, the magnetic flux density of the first core 21 reaches saturation. The inductance in the first core 21 remains relatively constant within a small range, and the inductance in the second core 22 also remains essentially constant. Therefore, the total inductance of the reactor also remains approximately constant during this stage.

[0031] Fourth stage: As the current continues to increase, reaching approximately 16-18A, the inductance in the first core 21 remains constant. During this stage, the magnetic flux density of the second core 22 approaches saturation, its permeability gradually decreases, and its inductance gradually decreases. At this point, the total inductance also gradually decreases.

[0032] Fifth stage: The elevator load continues to increase until it reaches full load. At this time, the current also continues to increase, and the magnetic flux density of the second iron core 22 is also in a saturated state. The inductance in both the first iron core 21 and the second iron core 22 remains basically unchanged. Therefore, the total inductance of the reactor also remains approximately unchanged during this stage.

[0033] Through the above five stages, as the elevator load increases, the total inductance of the reactor changes in a near-step manner from large to small as the current increases. This allows it to adapt well to the operating characteristics of the elevator, which is beneficial for optimizing elevator performance.

[0034] Although the present invention has been described above with reference to preferred embodiments, this does not mean that the scope of the present invention is limited to the structure described above. Any equivalent alternative structures that can be easily developed by those skilled in the art after reading the above description, and any equivalent changes and modifications made without departing from the spirit and scope of the present invention, should be covered within the scope of the present invention.

Claims

1. A soft-characteristic reactor structure, characterized in that, include: An upper yoke, a lower yoke, and three iron core posts wound with coils; Each core column includes: a first core and a second core made of silicon steel with different magnetic permeability, wherein the magnetic permeability of the first core is higher than that of the second core, the first core has multiple first air gaps, the second core has multiple second air gaps, the first core and the second core are assembled together to form the core column, and the coil is wound around the outside of the core column to form the core column with the coil wound. The upper yoke includes a first upper yoke and a second upper yoke, and the lower yoke includes a first lower yoke and a second lower yoke. The first iron core is disposed between the first upper yoke and the first lower yoke, and the second iron core is disposed between the second upper yoke and the second lower yoke. The first upper yoke, the first lower yoke, and the first core are made of the same silicon steel material, and the second upper yoke, the second lower yoke, and the second core are made of the same silicon steel material. The difference in magnetic permeability between the first and second iron cores, the first air gap, and the second air gap are configured such that the total inductance of the reactor changes from large to small in an almost stepwise manner as the current increases within the range of current variation.

2. The soft-characteristic reactor as described in claim 1, characterized in that: Both the first and second iron cores are made of grain-oriented silicon steel.

3. The soft-characteristic reactor as described in claim 1, characterized in that: Both the first and second iron cores are made of non-oriented silicon steel.

4. The soft-characteristic reactor as described in claim 1, characterized in that: The first iron core is made of oriented silicon steel / non-oriented silicon steel, and the second iron core is made of non-oriented silicon steel / oriented silicon steel.

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