Controllable reactor and high-power controllable filter
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUANGDONG GUANGDA ELECTRICAL
- Filing Date
- 2025-06-12
- Publication Date
- 2026-06-12
AI Technical Summary
Traditional passive LC filters can only filter harmonics of fixed frequencies, and the filtering effect is greatly affected by changes in system parameters. It is difficult to flexibly control the magnitude of the filtering current, resulting in a large footprint and high operational requirements.
A controllable reactor is used. By setting an auxiliary winding on the iron core to receive harmonic currents of different magnitudes, the impedance of the reactor can be controlled. Combined with an active control circuit, different magnitudes of harmonic currents are generated to form a controllable filter to filter out different harmonics. At the same time, the inductance value is adjusted by using the air gap to adapt to different harmonic frequencies.
It achieves effective filtering of different harmonics, reduces the footprint and operation difficulty, improves waveform accuracy and reduces system cost.
Smart Images
Figure CN224355097U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power equipment technology, and in particular to a controllable reactor and a high-power controllable filter. Background Technology
[0002] In power systems, harmonic problems severely affect power quality and threaten the safe and stable operation of power equipment. Currently, common harmonic suppression methods mainly include active filtering and passive filtering. Active filtering cancels harmonics in the system by generating reverse harmonics, but it suffers from high cost and limited capacity. Passive filtering, on the other hand, uses an LC circuit to create a low-impedance path for specific harmonics, guiding the harmonic current into the LC circuit, thereby achieving the filtering purpose.
[0003] However, as Figure 1 As shown, traditional passive LC filters can typically only filter harmonics of fixed frequencies, and their filtering effect is greatly affected by changes in system parameters, making it difficult to flexibly control the magnitude of the filter current. Specifically, different harmonics, such as the 5th, 7th, and 11th harmonics, are generated in substations. Current solutions use different branches to filter different harmonics separately, resulting in a large footprint and requiring a specific order for the filtering branches to be activated: first the 5th harmonic filter, then the 7th, then the 11th; and when disconnecting, first disconnect the 11th, then the 7th, and finally the 5th. Incorrect activation / disconnection can cause system resonance, meaning the operation is also quite demanding. Therefore, there is an urgent need for a harmonic filter with a smaller footprint and lower operational requirements. Utility Model Content
[0004] To address the shortcomings of existing technologies, this application provides a controllable reactor and a high-power controllable filter that can filter out harmonics of different orders, while also reducing the footprint and operational complexity.
[0005] In a first aspect, this application provides a controllable reactor using the following technical solution:
[0006] A controllable reactor includes a reactor body, the main winding of which is wound on an iron core, and the iron core is further provided with an auxiliary winding for receiving harmonic currents of different magnitudes to control the impedance of the reactor.
[0007] By adopting the above technical solution, the impedance of the reactor can be controlled by using the auxiliary winding set on the iron core to receive harmonic currents of different magnitudes. Thus, after the reactor and the capacitor form a filter, different harmonics can be filtered out, and the footprint and operation difficulty can be reduced at the same time.
[0008] This application further provides that the iron core is provided with an open air gap.
[0009] By adopting the above technical solution, the inductance value of the reactor body can be adjusted by changing the air gap value to meet the filtering requirements of different harmonic frequencies.
[0010] This application further specifies that the auxiliary winding comprises one strand.
[0011] By adopting the above technical solution, the structure of an auxiliary winding is simple and easy to implement.
[0012] This application further specifies that the auxiliary winding includes two windings, which are used to receive harmonic currents of different frequencies.
[0013] By adopting the above technical solution, different harmonic frequency generators can be used to control the generation of harmonic currents of different frequencies to be fed into the two auxiliary windings, which can effectively reduce losses, improve waveform accuracy, and reduce system costs.
[0014] Secondly, this application provides a high-power controllable filter using the following technical solution:
[0015] A high-power controllable filter, comprising:
[0016] A passive LC circuit, comprising any of the aforementioned controllable reactors, wherein the output terminal of the controllable reactor is electrically connected to one end of a capacitor, and the other end of the capacitor is grounded; the input terminal of the controllable reactor is connected to the power grid.
[0017] An active control circuit is connected to the auxiliary winding of the controllable reactor to generate harmonic currents of different magnitudes and inject them into the auxiliary winding of the controllable reactor.
[0018] By adopting the above technical solution, the active control circuit generates harmonic currents of different magnitudes and injects them into the auxiliary winding of the controllable reactor to control the impedance of the reactor. This enables the passive LC circuit to filter out harmonics of different orders, while also reducing the floor space and operation difficulty.
[0019] This application further specifies that the active control loop includes an IGBT harmonic generator and / or a SiC harmonic generator.
[0020] By adopting the above technical solutions, harmonics below the 15th order generally have a relatively high content. When filtering them, an IGBT harmonic generator with a switching frequency of 10-20kHz is used, which is more cost-effective. Harmonics above the 15th order are mostly of relatively low content. A SiC harmonic generator with a switching frequency of 30-40kHz is used, which can effectively reduce losses and improve waveform accuracy. The combination of the two can effectively reduce losses, improve waveform accuracy, and reduce system costs at the same time.
[0021] This application further specifies that the active control loop also includes:
[0022] A signal detection module, which is electrically connected to the power system, is used to collect current and voltage signals in the power system in real time and analyze harmonic components and content signals;
[0023] The control system includes a signal detection module electrically connected to the control system, used to calculate and obtain the magnitude and phase of the harmonic current to be injected into the auxiliary winding based on the analysis results of the signal detection module.
[0024] By adopting the above technical solution, the signal detection module collects current and voltage signals in the power system in real time and analyzes the harmonic components and content; the control system obtains the magnitude and phase of the harmonic current injected into the auxiliary winding based on the analysis results of the signal detection module, so as to facilitate the control filter to filter out the harmonic.
[0025] This application further includes a short-circuit switch, which is connected to the output terminal of the active control circuit and both ends of the controllable reactor.
[0026] By adopting the above technical solution, when the system resonates, the control system short-circuits the output terminal, making the other end of the transformer form a high resistance, preventing harmonics from flowing into the filter branch, thereby preventing system resonance.
[0027] In summary, this application has the following beneficial effects:
[0028] This application utilizes an auxiliary winding mounted on the iron core to receive harmonic currents of different magnitudes to control the impedance of the reactor. Thus, when the reactor and capacitor form a filter, different harmonics can be filtered out, while also reducing the footprint and operational difficulty. Attached Figure Description
[0029] Figure 1 A schematic diagram of the circuit structure of a traditional passive LC filter;
[0030] Figure 2 This is a schematic diagram of the overall structure of a controllable reactor according to this application;
[0031] Figure 3 This is a schematic diagram of the overall structure of another controllable reactor in this application;
[0032] Figure 4 This is a schematic diagram of the circuit principle of a high-power controllable filter according to this application.
[0033] Figure reference numerals: 2. Main winding; 3. Iron core; 4. Passive LC circuit; 40. Auxiliary winding; 5. Air gap; 7. Active control circuit; 71. Signal detection module; 72. Control system. Detailed Implementation
[0034] The following is in conjunction with the appendix Figures 2-4 This application will be described in further detail.
[0035] refer to Figures 2-3 In this embodiment, a controllable reactor includes a reactor body, a main winding 2 wound around an iron core 3, and an auxiliary winding 40 provided on the iron core 3. The auxiliary winding 40 is used to receive harmonic currents of different magnitudes to control the impedance of the reactor. Specifically, the iron core 3 can be a three-phase iron core or a single-phase iron core.
[0036] Furthermore, the iron core 3 is provided with intermittent air gaps 5, so that the reactance value of the reactor can be adjusted by adjusting the size of the air gaps 5; after fixing the size of the air gaps during production, the reactance value of the reactor can be further adjusted by combining it with the auxiliary winding 40.
[0037] For example, assuming the input electrical signal voltage is 100V and the current flowing through the main winding of the reactor is 100A, the inductance of the reactor body would be 1 ohm if existing technology were used. However, by adding an auxiliary winding 40, the reactance of the reactor can be adjusted by varying the current in the auxiliary winding 40. For instance, when a reverse current of 200A is flowing through the auxiliary winding 40, the reactance of the reactor body drops to 0.33 ohms, and so on.
[0038] refer to Figure 2 In one embodiment, the auxiliary winding 40 comprises one winding, which controls the impedance of the reactor, resulting in a simple structure and ease of implementation. LA-A1A2 is the main winding 2 (LA), where A1 represents the input terminal and A2 represents the output terminal. L1-X1X2 is the first auxiliary winding 40 (L1), where X1 represents the input terminal and X2 represents the output terminal. The impedance of the reactor is controlled by controlling the harmonic currents of different frequencies and magnitudes flowing into the auxiliary winding L1.
[0039] In practice, the reactor can be a single-phase reactor or a three-phase reactor.
[0040] like Figure 2 This is a three-phase reactor, where the main winding LA and auxiliary winding L1 of each phase are simultaneously wound on a single iron core column. For illustration purposes, Figure 2 Only the main winding LA and auxiliary winding L1 set on phase A are shown.
[0041] refer to Figure 3In another embodiment, the auxiliary winding 40 includes two windings: LA-A1A2 is the main winding 2 (LA), where A1 represents the input terminal and A2 represents the output terminal. L1-X1X2 is the first auxiliary winding 40 (L1), where X1 represents the input terminal and X2 represents the output terminal; L2-X3X4 is the second auxiliary winding 40 (L2), where X3 represents the input terminal and X4 represents the output terminal. Harmonics below the 15th order generally have a relatively high content, so auxiliary winding L1 is used for filtering, employing an IGBT harmonic generator with a switching frequency of 10-20kHz, which is less costly. Harmonics above the 15th order are mostly of relatively low content, so auxiliary winding L2 is used, employing a SiC harmonic generator with a switching frequency of 30-40kHz, which can effectively reduce losses and improve waveform accuracy.
[0042] Similarly, in practice, the reactor can be a single-phase reactor or a three-phase reactor.
[0043] like Figure 3 This is a three-phase reactor, where the main winding LA and auxiliary windings L1 and L2 of each phase are simultaneously wound on a single iron core column. For illustration purposes, Figure 3 Only the main winding LA and auxiliary windings L1 and L2 set on phase A are shown.
[0044] This application also discloses a high-power controllable filter applicable to any of the above-mentioned controllable reactors. (See reference...) Figure 2 and Figure 4 A high-power controllable filter includes a passive LC circuit 4, which comprises any of the aforementioned controllable reactors. The output terminal of the controllable reactor is electrically connected to a capacitor, the other end of which is grounded. The input terminal of the controllable reactor is connected to the power grid. The high-power controllable filter also includes an active control circuit 7, which is electrically connected to the auxiliary winding 40 of the controllable reactor to generate harmonic currents of different magnitudes.
[0045] When a specific harmonic current is injected, the reactor body exhibits low impedance characteristics to the injected harmonic, thereby guiding the harmonic current smoothly through the reactor body into the capacitor, achieving harmonic filtering. Simultaneously, the magnitude of the filtered current can be controlled by adjusting the injected current.
[0046] Specifically, a harmonic generator can be used as a device to inject harmonic current into the auxiliary winding 40.
[0047] Optionally, the active control circuit 7 includes an IGBT harmonic generator and / or a SiC harmonic generator. Specifically, harmonics below the 15th order generally have a relatively high content, and are filtered using an auxiliary winding L1 with an IGBT harmonic generator at a switching frequency of 10-20 kHz, resulting in lower costs. Harmonics above the 15th order are mostly of lower content, and are filtered using an auxiliary winding L2 with a SiC harmonic generator at a switching frequency of 30-40 kHz, which can effectively reduce losses and improve waveform accuracy.
[0048] In this embodiment of the application, the active control loop 7 further includes a signal detection module 71 and a control system 72. The signal detection module 71 is electrically connected to the power system and is used to collect current and voltage signals in the power system in real time and analyze harmonic components and content signals. The signal detection module 71 is electrically connected to the control system 72, and the control system 72 is used to calculate and obtain the magnitude and phase of the harmonic current to be injected into the auxiliary winding 40 based on the analysis results of the signal detection module 71.
[0049] Specifically, the signal detection module 71 can employ a high-precision current transformer or voltage transformer to acquire current or voltage signals in the power system in real time and transmit the signals to the control system 72. The control system 72 can employ a high-performance digital signal processor (DSP) or field-programmable gate array (FPGA) to perform Fast Fourier Transform (FFT) analysis on the acquired signals to obtain harmonic components and content. These are all existing modules and will not be described in detail here.
[0050] For example, when a 5th harmonic is detected in the power system, the control system 72 calculates the magnitude and phase of the 5th harmonic current to be injected, and then injects the 5th harmonic current into the auxiliary winding L1. This causes the reactor to exhibit low impedance characteristics to the 5th harmonic, guiding the 5th harmonic current smoothly through the reactor into the capacitor, thus filtering the 5th harmonic. Simultaneously, the magnitude of the filtering current can be controlled by adjusting the output current according to actual needs.
[0051] Furthermore, a high-power controllable filter also includes a short-circuit switch, which is connected to the output terminal of the active control loop 7 and both ends of the controllable reactor, respectively. Thus, when the system resonates, the control loop short-circuits the output terminal. Figure 4 By utilizing the principle of electromagnetic induction, the inductance of the LC filter branch becomes high-impedance, preventing harmonics from flowing into the LC filter branch and thus preventing system resonance.
[0052] The implementation principle of a high-power controllable filter according to an embodiment of this application is as follows: the signal detection module 71 collects the current or voltage signal in the power system in real time and transmits the signal to the control system 72. The control system 72 analyzes the collected signal, obtains the harmonic components and content, calculates the magnitude and phase of the harmonic current to be injected into the auxiliary winding 40, and injects the corresponding harmonic current into the auxiliary winding 40; an auxiliary winding 40 is added to the reactor body, and the auxiliary winding 40 and the main winding 2 of the reactor body are on the same iron core. The iron core is provided with an air gap 5 and is in an open state, such as... Figure 4 The method utilizes the principle of electromagnetic induction. With the voltage across the reactor body remaining constant, the harmonic current flowing through the auxiliary winding 40 is adjusted, causing a change in the magnetic field. This, in turn, affects the current in the main winding 2, which is on the same iron core as the auxiliary winding 40, thereby adjusting the impedance of the reactor body. The change in the impedance of the reactor body causes a change in the impedance of the reactor in the LC filter branch, which in turn filters out the corresponding harmonics.
[0053] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A controllable reactor, characterized in that, The reactor body includes a main winding (2) of which is wound around an iron core (3). The iron core (3) is also provided with an auxiliary winding (40) for receiving harmonic currents of different magnitudes to control the impedance of the reactor.
2. The controllable reactor according to claim 1, characterized in that, The iron core (3) is provided with intermittent air gaps (5).
3. A controllable reactor according to claim 1, characterized in that, The auxiliary winding (40) includes one.
4. A controllable reactor according to claim 1, characterized in that, The auxiliary winding (40) includes two windings, which are used to receive harmonic currents of different frequencies.
5. A high-power controllable filter, characterized in that, include: A passive LC circuit (4) includes a controllable reactor as described in any one of claims 1-4, wherein the output terminal of the controllable reactor is electrically connected to one end of a capacitor and the other end of the capacitor is grounded; and the input terminal of the controllable reactor is connected to the power grid. An active control circuit (7) is connected to the auxiliary winding (40) of the controllable reactor to generate harmonic currents of different magnitudes and inject them into the auxiliary winding (40) of the controllable reactor.
6. The high-power controllable filter according to claim 5, characterized in that, The active control loop (7) includes an IGBT harmonic generator and / or a SiC harmonic generator.
7. The high-power controllable filter according to claim 5, characterized in that, The active control loop (7) also includes: The signal detection module (71) is electrically connected to the power system and is used to collect current and voltage signals in the power system in real time and analyze harmonic components and content signals. The control system (72) is electrically connected to the signal detection module (71) and is used to calculate the magnitude and phase of the harmonic current to be injected into the auxiliary winding (40) based on the analysis results of the signal detection module (71).
8. The high-power controllable filter according to claim 5, characterized in that, It also includes a short-circuit switch, which is connected to the output terminal of the active control circuit (7) and the two ends of the controllable reactor respectively.