Improved active filter control method and system for harmonic suppression of mine frequency conversion cable

Abstract

The present application relates to a kind of active filter control method and system of improvement type harmonic suppression of mine frequency conversion cable.The method includes: real-time acquisition of the voltage and current signal of mine power system;Based on the positive sequence component of fundamental voltage extracted by non-locked loop synchronous detection method;Based on the active power balance principle, the active power component required to maintain the stability of the DC side voltage of converter is calculated, and the average power generation command current signal is combined with load;Instruction current and actual compensation current are sent into hysteresis comparator for direct current control to generate PWM pulse, drive converter to output opposite compensation current and inject into mine frequency conversion cable to offset harmonic current.The present application eliminates the hardware circuit of phase-locked loop, reduces cost and improves response speed;Without complex parameter setting, it is simple to realize;Hysteresis control response speed is fast, applicable to harmonic fast change scene.

Description

Technical Field

[0001] This invention relates to the field of active filter control technology; specifically, this invention relates to an improved active filter control method and system for harmonic suppression of mining frequency conversion cables. Background Technology

[0002] In the mining industry, including coal mining, the widespread application of automation and intelligent technologies has led to the extensive use of variable frequency drive (VFD) equipment. VFD technology, with its superior speed control performance, significant energy-saving effects, and flexible control methods, has become a key means of improving the operating efficiency of mining equipment and reducing energy consumption. However, VFD equipment inevitably generates harmonic currents during operation. These harmonic currents, transmitted through mining VFD cables, pose numerous serious problems to the mine's power system, severely impacting the safety and stability of mine production.

[0003] In the field of filter control, there are various harmonic suppression methods. For example, the hybrid pulse width modulation (PWM) harmonic suppression technology for dual three-phase motors adds an extra switching operation to make the distribution of the switching frequency and its integer multiples of harmonics more balanced. However, its filtering effect is limited by grid parameters, can only eliminate specific harmonics, and is prone to inducing grid resonance, which brings safety risks.

[0004] For example, current-controlled harmonic resonance suppression technology analyzes the transfer function from input voltage to output current and uses the Bode stability criterion to implement a capacitor current feedback active damping strategy for resonance suppression. However, in practical applications, it is susceptible to interference from various factors such as electromagnetic interference, temperature fluctuations, and mechanical vibrations, resulting in unsatisfactory compensation effects.

[0005] Therefore, it is necessary to improve and optimize existing active filter control technology to effectively address the harmonic problems in mine power systems. Summary of the Invention

[0006] In view of this, the present invention provides an improved active filter control method and system for harmonic suppression of mining variable frequency cables, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0007] To achieve the aforementioned objective, a first aspect of the present invention provides an improved active filter control method for harmonic suppression in mining frequency conversion cables, comprising the following steps:

[0008] Real-time acquisition of three-phase AC voltage and three-phase load current of the mining power system, as well as the actual voltage of the DC-side capacitor of the active filter converter;

[0009] Based on the phase-locked loop-free synchronous detection method, the three-phase AC voltage is processed to extract the positive sequence component of the fundamental voltage.

[0010] Based on the active power balance principle, the active power component required to maintain the stability of the DC side voltage of the converter is calculated according to the voltage command value of the DC side capacitor and the actual voltage.

[0011] The average load power is calculated based on the three-phase load current, and the command current signal is generated by combining the active power component required to maintain the DC side voltage stability of the converter and the positive sequence component of the fundamental voltage.

[0012] The actual output compensation current of the active filter converter is obtained, and the command current signal and the actual output compensation current are sent to the hysteresis comparator for direct current control to generate a PWM pulse signal for driving the switching device.

[0013] The switching devices of the active filter converter, driven by the PWM pulse signal, output a compensation current with the same amplitude but opposite phase to the harmonic current of the power grid, and inject it into the mining frequency conversion cable to cancel the harmonic current.

[0014] In the method described above, optionally, the step of extracting the positive-sequence component of the fundamental voltage includes:

[0015] Three-phase AC voltage The voltage components in the rotated orthogonal coordinate system are obtained through Park transformation. Its transformation formula is:

[0016] ,

[0017] ,

[0018] The voltage component After filtering by a low-pass filter, the corresponding DC component is extracted. :

[0019] ,

[0020] The DC component Perform the inverse Park transform and obtain the positive sequence component of the fundamental voltage by looking up the sine and cosine tables. :

[0021] .

[0022] In the method described above, optionally, the step of calculating the active power component required to maintain the DC-side voltage stability of the converter includes:

[0023] The DC-side capacitor value is set to Q, and the DC-side capacitor voltage command value is... The actual voltage value is Calculate the active power required to stabilize the voltage. :

[0024] ,

[0025] Set the required energy The active power component that the power source needs to replenish during one power cycle K is calculated based on the power supplied by the power source. :

[0026] .

[0027] In the method described above, optionally, the step of generating the command current signal includes:

[0028] Based on the three-phase instantaneous power of the load Calculate the average power of the load :

[0029] ,

[0030] in, Represents the power supply voltage cycle;

[0031] set up Calculate the proportionality coefficient d between the current and voltage of the power supply:

[0032] ,

[0033] The fundamental positive-sequence component of the power supply current is calculated using the proportional coefficient d and used as the command current signal. :

[0034] .

[0035] In the method described above, optionally, after the step of real-time acquisition of the three-phase AC voltage and three-phase load current of the mining power system, and the actual voltage of the DC-side capacitor of the active filter converter, the method further includes using... The algorithm steps for detecting harmonic current in mining frequency conversion cables are as follows:

[0036] Three-phase load current The instantaneous current is converted into a two-phase orthogonal coordinate system using the Clarke transform. ;

[0037] Combining the principle of instantaneous reactive power, Converted to instantaneous active current and instantaneous reactive current ;

[0038] The instantaneous active current and instantaneous reactive current Perform an inverse transformation to obtain the distorted harmonic current. It is used for system harmonic monitoring and evaluation.

[0039] In the method described above, optionally, the step of feeding the command current signal and the actual output compensation current into a hysteresis comparator for direct current control includes:

[0040] A tolerance range is preset, and the difference between the command current and the actual output compensation current is input into the hysteresis comparator.

[0041] When the difference exceeds the upper or lower limit of the tolerance range, the hysteresis comparator outputs a flip signal to generate a corresponding PWM pulse signal to drive the switching device to adjust the actual output compensation current so that it follows the change of the command current.

[0042] To achieve the aforementioned objectives, a second aspect of the present invention provides an improved active filter control system for harmonic suppression of mining frequency conversion cables, used to implement the method as described in any one of the first aspects above, characterized in that it includes:

[0043] The data acquisition module is used to collect the three-phase AC voltage and three-phase load current of the mining power system in real time, as well as the actual voltage of the DC side capacitor of the active filter converter.

[0044] The fundamental voltage extraction module is used to process the three-phase AC voltage based on the phase-locked loop-free synchronous detection method and extract the positive sequence component of the fundamental voltage.

[0045] A DC voltage regulator module is used to calculate the active power component required to maintain the DC side voltage stability of the converter based on the active power balance principle, according to the voltage command value of the DC side capacitor and the actual voltage.

[0046] The command current generation module is used to calculate the average load power based on the three-phase load current, and combine the active power component required to maintain the DC side voltage stability of the converter and the positive sequence component of the fundamental voltage to generate a command current signal.

[0047] The hysteresis control module is used to obtain the actual output compensation current of the active filter converter, and send the command current signal and the actual output compensation current into the hysteresis comparator for direct current control to generate a PWM pulse signal for driving the switching device.

[0048] The compensation current output module includes an active filter converter. The switching device of the active filter converter, driven by the PWM pulse signal, outputs a compensation current with the same amplitude but opposite phase to the grid harmonic current and injects it into the mining frequency conversion cable.

[0049] In the system described above, optionally, the active filter converter adopts a three-phase voltage-source PWM converter topology, which includes:

[0050] DC-side capacitors are used to store DC energy and maintain DC-side voltage stability.

[0051] The power module, composed of IGBTs, is controlled to turn on and off by the PWM pulse signal;

[0052] An AC-side output inductor is connected in series between the AC output terminal of the power module and the mining frequency converter cable to compensate for the output current.

[0053] To achieve the foregoing objectives, a third aspect of the present invention provides an electronic device, characterized in that it includes a memory and a processor connected to the memory, wherein the memory stores a computer program executable by the processor, and the processor executes the computer program to implement the method as described in any one of the foregoing first aspects.

[0054] To achieve the foregoing objectives, a fourth aspect of the present invention provides a computer-readable storage medium, characterized in that it stores a computer program thereon, which, when executed by a processor, implements the method as described in any one of the first aspects above.

[0055] The improved active filter control method for harmonic suppression in mining frequency converter cables of the present invention extracts the positive sequence component of the fundamental voltage by adopting a phase-locked loop-free synchronous detection method, eliminating the need for phase-locked loop hardware circuitry, reducing system cost and improving response speed; it stabilizes the DC side voltage based on the active power balance principle, requiring no complex parameter tuning, making it simple to implement and not increasing hardware costs; it uses a hysteresis comparator for direct current control, resulting in fast response speed, and the current tracking error is only related to the preset tolerance, making it suitable for scenarios where harmonics in mining frequency converter equipment change rapidly.

[0056] The present invention further provides an improved active filter control system for harmonic suppression of mining frequency conversion cables, an electronic device, and a computer-readable storage medium for implementing the above-described method. Therefore, the system, electronic device, and computer-readable storage medium also have the above-described advantages. Attached Figure Description

[0057] The disclosure of this invention will become more apparent from the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings:

[0058] Figure 1 This is a schematic diagram of the structure of a mining frequency converter according to an embodiment of the present invention;

[0059] Figure 2 This is a schematic diagram of the hysteresis current control structure provided in an embodiment of the present invention;

[0060] Figure 3 This is a schematic diagram comparing the harmonic current suppression effects provided in the embodiments of the present invention;

[0061] Figure 4 This is a schematic diagram comparing power factor results provided in an embodiment of the present invention. Detailed Implementation

[0062] Referring to the accompanying drawings and specific embodiments, the structure, composition, features, and advantages of the present invention will be described below by way of example; however, all descriptions should not be construed as limiting the present invention in any way.

[0063] It should be noted that, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the various figures, the present invention still allows for any combination or deletion among these technical features (or their equivalents) without any technical obstacle. Therefore, these further embodiments according to the present invention should also be considered within the scope of this description.

[0064] It should be noted that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.

[0065] It should be noted that the use of the terms "upper," "lower," "left," "right," and similar terms to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings is only for the convenience of describing this disclosure and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0066] It should be noted that the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," "third," or "fourth" may explicitly or implicitly include at least one of those features.

[0067] It should be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; wired connections or wireless connections; direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0068] One or more embodiments of the present invention provide an improved active filter control method for harmonic suppression in mining variable frequency cables. This method optimizes the control of harmonics generated by mining variable frequency equipment.

[0069] Mining frequency converters typically employ pulse width modulation (PWM) technology, which converts direct current (DC) into alternating current (AC) with adjustable frequency and amplitude by controlling the switching on and off of power electronic devices. For example... Figure 1 As shown, exemplarily, the core components of a mining frequency converter include a three-phase AC-DC rectifier (“AC-DC converter”), an LC filter, and a high-frequency DC-DC converter circuit. Specifically, its topology can be found in [reference needed]. Figure 1 ,in These represent the instantaneous voltage of the power grid, This represents the instantaneous current; after transforming to a two-phase orthogonal coordinate system, Indicates instantaneous voltage. This represents the instantaneous current; the output of the AC-DC converter module is connected in series with an inductor labeled L and in parallel with a capacitor labeled Q; at this node, the current is labeled to the right. Voltage is marked downwards. This node is connected to a high-frequency DC-DC converter module; the output of the high-frequency DC-DC converter module is connected to an output filter module; the output of the output filter module is marked with current to the right. Voltage is marked downwards. The directions mentioned above represent the reference directions for the current and voltage as indicated in the illustrated examples.

[0070] The pre-amplifier circuit plays a decisive role in the harmonic content generated during the charging process. In engineering applications, common types of rectifier circuits include uncontrolled rectifiers, Vienna rectifiers, and two-level rectifiers. During the switching process, the current waveform contains abundant harmonic components, which are transmitted to the power grid through mining frequency conversion cables, causing pollution to the power grid. The method provided in this invention aims to effectively suppress these harmonics.

[0071] Specifically, the method may include the following steps:

[0072] Step S1: Real-time acquisition of the three-phase AC voltage and three-phase load current of the mining power system, as well as the actual voltage of the DC-side capacitor of the active filter converter.

[0073] According to one or more embodiments of the present invention, the active filter converter of the mining frequency converter equipment can adopt a three-phase voltage-type PWM converter topology, which includes a DC-side capacitor for storing DC energy and maintaining DC-side voltage stability, a power module composed of IGBT (Insulated Gate Bipolar Transistor) that is controlled to be turned on and off by a PWM pulse signal, and an AC-side output inductor connected in series between the AC output terminal of the power module and the mining frequency converter cable for smoothing the output compensation current.

[0074] Step S2: Based on the phase-locked loop-free synchronous detection method, the collected three-phase AC voltage is processed to extract the positive sequence component of the fundamental voltage.

[0075] According to one or more embodiments of the present invention, the extraction process may specifically include:

[0076] The three-phase AC voltage is transformed using the Park transformation (a coordinate transformation method that transforms variables in a three-phase stationary coordinate system to a two-phase rotating orthogonal coordinate system) to obtain the voltage components in the rotating orthogonal coordinate system. The specific calculation formula is as follows:

[0077]

[0078]

[0079] The voltage component is filtered by a low-pass filter to extract the corresponding DC component, which is expressed by the following formula:

[0080]

[0081] The DC component is subjected to an inverse Park transform, and the positive-sequence component of the fundamental voltage is obtained by looking up a pre-stored sine and cosine table (i.e., by looking up the sine and cosine table). Its expression formula is as follows:

[0082]

[0083] The above method eliminates the need to design phase-locked loop hardware circuits, which reduces the cost of hardware circuits and improves the system response speed.

[0084] Step S3: Based on the active power balance principle, calculate the active power component required to maintain the DC side voltage stability of the converter according to the voltage command value of the DC side capacitor and the actual collected voltage value.

[0085] According to one or more embodiments of the present invention, the calculation steps may specifically include:

[0086] The DC-side capacitor value is set to Q, and the DC-side capacitor voltage command value is... The actual voltage value is Calculate the active power required to stabilize the voltage. :

[0087]

[0088] Set the required energy The active power component that needs to be supplied by the power source within one power cycle K is calculated. , can be represented as:

[0089]

[0090] The above operations do not require parameter selection and tuning of the PI (proportional-integral) controller, making them relatively easy to implement and without increasing hardware costs.

[0091] Step S4: Calculate the average load power based on the collected three-phase load current, and combine the calculated active power component required to maintain the DC side voltage stability of the converter with the extracted fundamental voltage positive sequence component to generate a command current signal.

[0092] According to one or more embodiments of the present invention, a command current can be generated by a phase-locked loop-free synchronization detection method based on power supply voltage, specifically including:

[0093] Based on the three-phase instantaneous power of the load Calculate the average power of the load :

[0094]

[0095]

[0096] in, Represents the power supply voltage cycle;

[0097] Set the sum of squares of the positive sequence components of the three-phase fundamental voltage for The proportionality coefficient d between the current and voltage of the power supply is calculated using the following formula:

[0098]

[0099] The fundamental positive-sequence component of the power supply current is calculated using the scaling factor d, and used as the required command current signal. The expression is as follows:

[0100]

[0101] The command current generated by the synchronous detection method ensures the accuracy of the command.

[0102] Step S5: Obtain the actual output compensation current of the active filter converter, and send the command current signal and the actual output compensation current into the hysteresis comparator for direct current control to generate a PWM pulse signal for driving the switching devices.

[0103] For the hysteresis current control structure, please refer to Figure 2 .like Figure 2 As shown, this step utilizes a hysteresis comparator, pre-setting a tolerance range, to control the command current. Compensation current compared to actual output The difference is input to a hysteresis comparator; when the difference exceeds the upper or lower limit of the tolerance range, the hysteresis comparator outputs a state flip signal, generating a corresponding PWM pulse signal to drive the switching device to adjust the actual output compensation current. This allows it to follow changes in the commanded current. Hysteresis current control, as a direct current control method, has the advantage of fast response speed, and its dynamic error in current tracking depends only on the preset hysteresis width (i.e., tolerance range), and is independent of the rate of current change, making it very suitable for applications where harmonic currents in mining frequency converters change rapidly. Compared to indirect current control, which has shortcomings such as slow dynamic response and high sensitivity to parameters, the aforementioned hysteresis current control can meet the requirements of active power filter control technology in mining frequency converters for fast and accurate harmonic compensation.

[0104] Step S6: Under the drive of the aforementioned PWM pulse signal, the switching devices of the active filter converter output a compensation current with the same amplitude and opposite phase as the grid harmonic current, and inject it into the mining frequency converter cable to cancel the harmonic current, thereby realizing active compensation and suppression of harmonics.

[0105] Optionally, in one or more embodiments of the present invention, after the aforementioned step S1, the method of employing... The algorithm performs the following steps to detect harmonic currents in mining frequency converter cables, which are used for system harmonic monitoring and evaluation:

[0106] These represent the instantaneous voltage of the power grid, This indicates instantaneous current. In an orthogonal coordinate system, the instantaneous voltage of two phases is represented by... To represent, instantaneous current is... This method converts the three-phase load current into an instantaneous current in a two-phase orthogonal coordinate system using the Clarke transformation (a transformation method that transforms a three-phase stationary coordinate system to a two-phase stationary orthogonal coordinate system). The formula for this transformation is as follows:

[0107]

[0108]

[0109]

[0110] Then, by using the current in the three-phase circuit To represent the instantaneous active power in the circuit and instantaneous reactive power Its specific expression is as follows:

[0111]

[0112] Based on this, and combining the principle of instantaneous reactive power, the converted current is decomposed into instantaneous active current. and instantaneous reactive current The formula is as follows:

[0113]

[0114]

[0115] The distorted harmonic current is obtained by inversely transforming the instantaneous active current and instantaneous reactive current. The calculation formula is as follows:

[0116]

[0117] The above adopts The algorithm's steps for detecting harmonic currents in mining frequency converter cables involve only a few steps in the calculation. and ( (where t is the angular frequency and t is the time), it can accurately detect harmonic currents even under voltage waveform distortion conditions.

[0118] In a verification experiment of this invention, to verify the effectiveness of the above method, a simulation model was built in the Matlab / Simulink environment. The main circuit parameters of this experiment are shown in Table 1 below:

[0119] Table 1 Active Filter Parameters

[0120] parameter numerical values DC side reference voltage / V 800 Sampling frequency / kHz 20 DC side capacitor / μF 6500 Switching frequency / kHz 15 AC side inductance / mH 10 Damping resistance / Ω 1.0

[0121] The method provided in this embodiment of the invention (hereinafter referred to as "this method") is compared with existing hybrid pulse width modulation dual three-phase motor harmonic suppression technology (Comparison Method 1) and current control type harmonic resonance suppression technology (Comparison Method 2). Harmonic current and power factor are selected as experimental indicators. The results are as follows: Figure 3 and Figure 4 As shown.

[0122] Figure 3 This demonstrates the effect of harmonic current suppression. For example... Figure 3 As shown, this method can quickly respond to load changes and rapidly adjust the compensation current within a period after the control technology is activated, so that the current waveform quickly approaches a sine wave, effectively suppressing harmonic currents. Its harmonic suppression effect is significantly better than the other two methods.

[0123] Figure 4 The comparison of power factor results is shown. For example... Figure 4 As shown, the power factor before control was only about 0.64. After implementing the improved active filtering technology of this method, the power factor rapidly improved and stabilized above 0.90, while the other two methods showed poor power factor improvement and control performance. This indicates that this method has significant advantages in improving the system power factor and reducing reactive power losses.

[0124] The above experimental results show that the method provided in this embodiment of the invention performs well in terms of harmonic current suppression and system stability. It can achieve rapid and accurate suppression of harmonic current in mining frequency conversion cables, improve the power factor and power quality of coal mine power systems, and thus ensure the safe and stable operation of mining equipment.

[0125] Based on the same inventive concept, one or more embodiments of the present invention also provide an improved active filter control system for harmonic suppression of mining frequency conversion cables. Exemplarily, the system includes:

[0126] The data acquisition module is used to collect the three-phase AC voltage and three-phase load current of the mining power system in real time, as well as the actual voltage of the DC side capacitor of the active filter converter.

[0127] The fundamental voltage extraction module is used to process three-phase AC voltages based on a phase-locked loop-free synchronous detection method and extract the positive sequence component of the fundamental voltage.

[0128] The DC voltage regulator module is used to calculate the active power component required to maintain the DC side voltage stability of the converter based on the active power balance principle, according to the voltage command value and actual voltage of the DC side capacitor.

[0129] The command current generation module is used to calculate the average load power based on the three-phase load current, and combine the active power component required to maintain the DC side voltage stability of the converter and the positive sequence component of the fundamental voltage to generate the command current signal.

[0130] The hysteresis control module is used to obtain the actual output compensation current of the active filter converter, and send the command current signal and the actual output compensation current into the hysteresis comparator for direct current control to generate PWM pulse signals for driving switching devices.

[0131] The compensation current output module includes an active filter converter employing a three-phase voltage-source PWM converter topology. Driven by a PWM pulse signal, the switching devices of this active filter converter output a compensation current with equal amplitude but opposite phase to the grid harmonic current, which is injected into the mining frequency converter cable. As previously described, the active filter converter may include a DC-side capacitor, an IGBT power module, and an AC-side output inductor.

[0132] The modules work together to achieve all or at least some of the steps of the aforementioned method.

[0133] The improved active filter control system for harmonic suppression of mining variable frequency cables provided in this embodiment of the invention can execute the improved active filter control method for harmonic suppression of mining variable frequency cables provided in this embodiment of the invention. The implementation principle is similar. The actions performed by each module in the system of each embodiment of the invention correspond to the steps in the method of each embodiment of the application. For detailed functional descriptions of each module, please refer to the descriptions in the corresponding methods shown above, which will not be repeated here.

[0134] Based on the same inventive concept, embodiments of the present invention also provide an electronic device, which may include a memory and a processor connected to the memory. The memory may store a computer program, and the processor may be used to execute the computer program in the memory to implement the steps of the improved active filter control method for harmonic suppression of mining frequency conversion cables as described in any of the foregoing embodiments.

[0135] Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium on which a computer program can be stored, wherein when the computer program is executed, it implements the steps of the improved active filter control method for harmonic suppression of mining frequency conversion cables as described in any of the foregoing embodiments.

[0136] It should be noted that the computer-readable storage medium described above in this invention can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory, read-only memory, erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this invention, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0137] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.

[0138] The modules described in the embodiments of the present invention can be implemented in software or hardware. The names of the modules are not, in some cases, limiting the scope of the module itself.

[0139] In summary, the improved active filter control method, system, electronic equipment, and computer-readable storage medium for harmonic suppression of mining variable frequency cables provided by this invention overcomes the shortcomings of traditional methods, such as slow response speed, complex parameter tuning, susceptibility to interference, or high hardware costs, by combining technologies such as fundamental frequency extraction without phase-locked loops, DC voltage control with active power balance, and hysteresis direct current control. It significantly improves key performance indicators such as harmonic detection accuracy, compensation response speed, and system stability, achieving efficient, rapid, and stable suppression of harmonic currents in mining variable frequency cables. This reduces pollution to the power grid, effectively improves the power quality and power factor of the mine power system, provides a reliable guarantee for the safe, efficient, and stable operation of mining equipment, and ultimately enhances the economic and social benefits of mine production, promoting the green and intelligent development of mining power systems. It has broad application prospects.

[0140] The technical scope of this invention is not limited to the contents of the above specification. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the scope of this invention.

Claims

1. An improved active filter control method for harmonic suppression in mining frequency conversion cables, characterized in that, Includes the following steps: Real-time acquisition of three-phase AC voltage and three-phase load current of the mining power system, as well as the actual voltage of the DC-side capacitor of the active filter converter; Based on the phase-locked loop-free synchronous detection method, the three-phase AC voltage is processed to extract the positive sequence component of the fundamental voltage. Based on the active power balance principle, the active power component required to maintain the stability of the DC side voltage of the converter is calculated according to the voltage command value of the DC side capacitor and the actual voltage. The average load power is calculated based on the three-phase load current, and the command current signal is generated by combining the active power component required to maintain the DC side voltage stability of the converter and the positive sequence component of the fundamental voltage. The actual output compensation current of the active filter converter is obtained, and the command current signal and the actual output compensation current are sent to the hysteresis comparator for direct current control to generate a PWM pulse signal for driving the switching device. The switching devices of the active filter converter, driven by the PWM pulse signal, output a compensation current with the same amplitude but opposite phase to the harmonic current of the power grid, and inject it into the mining frequency conversion cable to cancel the harmonic current.

2. The method according to claim 1, characterized in that, The step of extracting the positive sequence component of the fundamental voltage includes: Three-phase AC voltage The voltage components in the rotated orthogonal coordinate system are obtained through Park transformation. Its transformation formula is: ， ， The voltage component After filtering by a low-pass filter, the corresponding DC component is extracted. : ， The DC component Perform the inverse Park transform and obtain the positive sequence component of the fundamental voltage by looking up the sine and cosine tables. : 。 3. The method according to claim 1, characterized in that, The steps for calculating the active power component required to maintain the DC-side voltage stability of the converter include: The DC-side capacitor value is set to Q, and the DC-side capacitor voltage command value is... The actual voltage value is Calculate the active power required to stabilize the voltage. : ， Set the required energy The active power component that the power source needs to replenish during one power cycle K is calculated based on the power supplied by the power source. : 。 4. The method according to claim 3, characterized in that, The step of generating the command current signal includes: Based on the three-phase instantaneous power of the load Calculate the average power of the load : ， in, Represents the power supply voltage cycle; set up Calculate the proportionality coefficient d between the current and voltage of the power supply: ， The fundamental positive-sequence component of the power supply current is calculated using the proportional coefficient d and used as the command current signal. : 。 5. The method according to claim 1, characterized in that, After the steps of real-time acquisition of the three-phase AC voltage and three-phase load current of the mining power system, and the actual voltage of the DC-side capacitor of the active filter converter, the method further includes using... The algorithm steps for detecting harmonic current in mining frequency conversion cables are as follows: Three-phase load current The instantaneous current is converted into a two-phase orthogonal coordinate system using the Clarke transform. ; Combining the principle of instantaneous reactive power, Converted to instantaneous active current and instantaneous reactive current ; The instantaneous active current and instantaneous reactive current Perform an inverse transformation to obtain the distorted harmonic current. It is used for system harmonic monitoring and evaluation.

6. The method according to claim 1, characterized in that, The steps of feeding the command current signal and the actual output compensation current into the hysteresis comparator for direct current control include: A tolerance range is preset, and the difference between the command current and the actual output compensation current is input into the hysteresis comparator. When the difference exceeds the upper or lower limit of the tolerance range, the hysteresis comparator outputs a flip signal to generate a corresponding PWM pulse signal to drive the switching device to adjust the actual output compensation current so that it follows the change of the command current.

7. An improved active filter control system for harmonic suppression of mining variable frequency cables, used to implement the method as described in any one of claims 1-6, characterized in that, include: The data acquisition module is used to collect the three-phase AC voltage and three-phase load current of the mining power system in real time, as well as the actual voltage of the DC side capacitor of the active filter converter. The fundamental voltage extraction module is used to process the three-phase AC voltage based on the phase-locked loop-free synchronous detection method and extract the positive sequence component of the fundamental voltage. A DC voltage regulator module is used to calculate the active power component required to maintain the DC side voltage stability of the converter based on the active power balance principle, according to the voltage command value of the DC side capacitor and the actual voltage. The command current generation module is used to calculate the average load power based on the three-phase load current, and combine the active power component required to maintain the DC side voltage stability of the converter and the positive sequence component of the fundamental voltage to generate a command current signal. The hysteresis control module is used to obtain the actual output compensation current of the active filter converter, and send the command current signal and the actual output compensation current into the hysteresis comparator for direct current control to generate a PWM pulse signal for driving the switching device. The compensation current output module includes an active filter converter. The switching device of the active filter converter, driven by the PWM pulse signal, outputs a compensation current with the same amplitude but opposite phase to the grid harmonic current and injects it into the mining frequency conversion cable.

8. The system according to claim 7, characterized in that, The active filter converter adopts a three-phase voltage-source PWM converter topology, which includes: DC-side capacitors are used to store DC energy and maintain DC-side voltage stability. The power module, composed of IGBTs, is controlled to turn on and off by the PWM pulse signal; An AC-side output inductor is connected in series between the AC output terminal of the power module and the mining frequency converter cable to compensate for the output current.

9. An electronic device, characterized in that, The method includes a memory and a processor connected to the memory, wherein the memory stores a computer program that can be executed by the processor, and the processor executes the computer program to implement the method as described in any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1-6.

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