Filter control method, device, equipment and medium in on-load tap-changing transformer

Abstract

The present invention discloses a filter control method, device, equipment, and medium for an on-load tap-changing transformer. The method includes: obtaining the circuit parameters of the output filter, the response time of the on-load tap-changing transformer, and the modulation wave amplitude of the on-load tap-changing transformer; constructing a system open-loop transfer function based on the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer; determining the cutoff frequency of the resonant link of the on-load tap-changing transformer based on the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer; and performing active damping control on the on-load tap-changing transformer based on the cutoff frequency of the resonant link of the on-load tap-changing transformer. Through the technical solution of the present invention, the infinite gain caused by the pole can be offset, achieving an ideal damping coefficient, and suppressing the resonance peak.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of computer technology, and in particular to a filter control method, device, equipment, and medium in an on-load tap-changing transformer. Background Art

[0002] The existing on-load tap-changing transformer does not take into account the influence of the leakage inductance of the main transformer, resulting in high-order harmonics near the resonant frequency in the converter output voltage, which in turn causes oscillation in the output current of the power electronic converter, affecting the normal operation of the on-load tap-changing transformer. Summary of the Invention

[0003] Embodiments of the present invention provide a filter control method, apparatus, device, and medium for an on-load tap-changing transformer. These methods can configure a resonant subzero point for an open-loop transfer function by adjusting a PIR parameter, thereby offsetting the infinite gain caused by a pole. Furthermore, by providing an appropriate cutoff frequency, an ideal damping coefficient for the system is achieved to suppress the resonant peak.

[0004] According to one aspect of the present invention, a filter control method in an on-load tap-changing transformer is provided, comprising:

[0005] Obtaining circuit parameters of the output filter, a response time of the on-load tap-changing transformer, and a modulation wave amplitude of the on-load tap-changing transformer;

[0006] Constructing a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer;

[0007] Determining a cutoff frequency of a resonant link of the on-load tap-changing transformer according to the open-loop transfer function of the system, a response time of the on-load tap-changing transformer, and an overshoot of the on-load tap-changing transformer;

[0008] Active damping control is performed on the on-load tap-changing transformer according to the cut-off frequency of the resonant link of the on-load tap-changing transformer.

[0009] According to another aspect of the present invention, a filter control device in an on-load tap-changing transformer is provided, the device comprising:

[0010] An acquisition module is used to acquire circuit parameters of the output filter, a response time of the on-load tap-changing transformer, and a modulation wave amplitude of the on-load tap-changing transformer;

[0011] A system open-loop transfer function construction module, configured to construct a system open-loop transfer function according to circuit parameters of the output filter and control parameters corresponding to the on-load tap-changing transformer;

[0012] A cutoff frequency determination module for the resonant link of the on-load tap-changing transformer, configured to determine the cutoff frequency of the resonant link of the on-load tap-changing transformer based on the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer;

[0013] An active damping control module is used to perform active damping control on the on-load tap-changing transformer according to the cut-off frequency of the resonant link of the on-load tap-changing transformer.

[0014] According to another aspect of the present invention, an electronic device is provided, comprising:

[0015] at least one processor; and

[0016] a memory communicatively connected to the at least one processor; wherein,

[0017] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the filter control method in the on-load tap-changing transformer according to any embodiment of the present invention.

[0018] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the filter control method in the on-load tap-changing transformer according to any embodiment of the present invention when executed.

[0019] The embodiment of the present invention obtains the circuit parameters of the output filter, the response time of the on-load tap-changing transformer, and the modulation wave amplitude of the on-load tap-changing transformer; constructs a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer; determines the cutoff frequency of the resonant link of the on-load tap-changing transformer according to the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer; and performs active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer, thereby offsetting the infinite gain caused by the pole, achieving an ideal damping coefficient, and suppressing the resonance peak.

[0020] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 is a flow chart of a filter control method in an on-load tap-changing transformer according to an embodiment of the present invention;

[0023] Figure 2 1 is a schematic diagram of a single-phase equivalent of a flexible on-load tap-changing transformer in an embodiment of the present invention;

[0024] Figure 3 It is a dual half-bridge converter based on an LCL filter in an embodiment of the present invention;

[0025] Figure 4 is an LCL circuit diagram for detecting grid-side voltage and input inductor current in an embodiment of the present invention;

[0026] Figure 5 is an equivalent circuit diagram for detecting the grid-side voltage and the input inductor current in an embodiment of the present invention;

[0027] Figure 6 1 is a system schematic diagram of PIR control in an embodiment of the present invention;

[0028] Figure 7 1 is a schematic structural diagram of a filter control device in an on-load tap-changing transformer according to an embodiment of the present invention;

[0029] Figure 8 It is a structural diagram of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] It is understandable that before using the technical solutions disclosed in the various embodiments of this disclosure, the type, scope of use, usage scenarios, etc. of the personal information involved in this disclosure should be informed to the user and the user's authorization should be obtained in an appropriate manner in accordance with relevant laws and regulations.

[0033] Example 1

[0034] Figure 1 This is a flow chart of a filter control method in an on-load tap-changing transformer provided by an embodiment of the present invention. This embodiment is applicable to the case of filter control in an on-load tap-changing transformer. The method can be executed by a filter control device in an on-load tap-changing transformer in an embodiment of the present invention. The device can be implemented in software and / or hardware. Figure 1 As shown, the method specifically includes the following steps:

[0035] S110 , obtaining circuit parameters of the output filter, a response time of the on-load tap-changing transformer, and a modulation wave amplitude of the on-load tap-changing transformer.

[0036] It should be noted that the on-load tap-changing transformer in the embodiment of the present invention is a flexible on-load tap-changing transformer. The flexible on-load tap-changing transformer includes: a main transformer, an on-load tap-changer, an input filter, an output filter, and a converter. The output filter includes: the leakage inductance of the main transformer, a first inductor, and a first capacitor.

[0037] In a specific example, Figure 2 is a single-phase equivalent schematic diagram of the flexible on-load tap-changing transformer, as shown in Figure 2 As shown in Figure 1, the flexible on-load tap-changing transformer includes: a main transformer, an on-load tap-changer, an input filter, an output filter, and a converter. The primary winding of the main transformer consists of the main winding N p0 The segmented winding N has the same number of turns as p1 ~N pn The secondary winding Ns is connected to the load, and the segmented winding N p0 ~Np(n-1) The tapping tap is connected to the on-load tap changer to realize the connection and disconnection of the segmented winding. pn As the energy-taking winding of the power electronic converter, it is always connected to the main circuit; the converter includes: a double half-bridge conversion circuit. The on-load tap changer includes: K0-K n-1 .

[0038] Due to the existence of leakage inductance of the main transformer T1, the leakage inductance is uniformly equivalent to the leakage inductance on the primary side main circuit, that is, the leakage inductance of the main transformer. If the voltage drop on the leakage inductance of the main transformer is not ignored, the main circuit voltage relationship can be expressed as:

[0039]

[0040] Among them, u g is the power supply voltage, K 12 The turns ratio of the main transformer T1, u C2 is the voltage across the first capacitor, i.e. the converter output voltage, i g is the main circuit current, L m The leakage inductance of the main transformer, u L is the resistor R L The voltage across both ends.

[0041] It can be seen from the above formula that the output voltage of the converter actually passes through an LCL filter.

[0042] Optionally, the output filter includes: a leakage inductance of a main transformer, a first capacitor, and a first inductor.

[0043] Specifically, one end of the first capacitor is respectively connected to the leakage inductance of the main transformer and the first inductor, the leakage inductance of the main transformer is connected to the main transformer, the main transformer is connected to one end of the input filter, the other end of the input filter is connected to one end of the converter, and the other end of the converter is respectively connected to the other end of the first capacitor and the other end of the first inductor.

[0044] Optionally, obtaining circuit parameters of the output filter includes:

[0045] Obtaining identification information of the on-load tap-changing transformer;

[0046] querying a database according to identification information of the on-load tap-changing transformer;

[0047] If the database contains a leakage inductance value of the main transformer corresponding to the identification information of the on-load tap-changing transformer, the capacitance value of the first capacitor is determined according to the leakage inductance value of the main transformer, the first proportional coefficient, the harmonic order, and the fundamental angular frequency, and the inductance value of the first inductor is determined according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor.

[0048] It should be noted that if the leakage inductance value of the main transformer can be obtained, the capacitance value of the first capacitor can be determined based on the leakage inductance value of the main transformer, the first proportional coefficient, the harmonic order and the fundamental angular frequency, and the inductance value of the first inductor can be determined based on the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order and the current of the first inductor.

[0049] Specifically, the capacitance value of the first capacitor may be determined according to the leakage inductance value, the first proportionality coefficient, the harmonic order, and the fundamental angular frequency of the main transformer by using the following formula:

[0050]

[0051] Among them, α is the first proportional coefficient, ω=ω0h=2πfh, ω0 is the fundamental angular frequency, h is the harmonic order, L m is the leakage inductance of the main transformer, and C2 is the capacitance of the first capacitor.

[0052] Optionally, determining the inductance of the first inductor according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor includes:

[0053] Determining the amplitude of each order harmonic of the converter output voltage according to the output voltage of the converter before filtering;

[0054] determining the amplitudes of each harmonic of the converter current according to the current of the first inductor;

[0055] The inductance value of the first inductor is determined according to the fundamental angular frequency, the amplitudes of each order harmonic of the converter output voltage, the harmonic order, and the amplitudes of each order harmonic of the converter current.

[0056] The current of the first inductor is the current flowing into the first inductor, such as Figure 2 i in L2 .

[0057] Specifically, the method of determining the amplitudes of each order harmonics of the converter output voltage according to the output voltage of the converter before filtering can be: performing Fourier decomposition on the output voltage of the converter before filtering to obtain the amplitudes of each order harmonics of the converter output voltage.

[0058] Specifically, the manner of determining the amplitudes of the various harmonics of the converter current according to the current of the first inductor may be: performing Fourier decomposition on the current of the first inductor to obtain the amplitudes of the various harmonics of the converter current.

[0059] Optionally, determining the inductance value of the first inductor according to the fundamental angular frequency, the amplitudes of each order harmonic of the converter output voltage, the harmonic order, and the amplitudes of each order harmonic of the converter current includes:

[0060] The inductance of the first inductor is determined based on the following formula:

[0061]

[0062] Where L2 is the inductance of the first inductor, u(h) is the amplitude of each harmonic of the converter output voltage, i(h) is the amplitude of each harmonic of the converter current, ω0 is the fundamental angular frequency, and h is the harmonic order.

[0063] Wherein, ω0=2πf, f is the frequency. In the embodiment of the present invention, the value of f can be 50.

[0064] In a specific example, the power electronic converter is the observation object, and the dual half-bridge converter based on the LCL filter can be obtained as follows: Figure 3 shown. Figure 3 in, u in is the equivalent input voltage of the converter, u con is the output voltage of the converter before filtering, u out is the output voltage of the converter after filtering, and R is the equivalent load of the converter.

[0065] It should be noted that the value of the inductance and the size of the filter can be reduced through the reasonable design of the LCL filter. Figure 3 As shown, if the leakage inductance of the main transformer and the capacitance of the first capacitor are not considered for the time being, the amplitude of each harmonic of the converter output voltage is u(h), and the amplitude of each harmonic of the converter current is limited to i(h) (h is the harmonic order).

[0066] Optionally, also include:

[0067] If the leakage inductance value of the main transformer corresponding to the identification information of the on-load tap-changing transformer does not exist in the database, the inductance value of the first inductor is determined according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor, the capacitance value of the first capacitor is determined according to the power ratio, the fundamental angular frequency, the output voltage of the converter after filtering, and the active power of the converter, and the leakage inductance value of the main transformer is determined according to the harmonic order, the fundamental angular frequency, and the first proportional coefficient.

[0068] Specifically, the method for determining the capacitance value of the first capacitor based on the power ratio, the fundamental angular frequency, the output voltage of the converter after filtering, and the active power of the converter can be: determining the reference impedance Zb based on the active power of the converter and the output voltage of the converter after filtering, and determining the capacitance value of the first capacitor based on the reference impedance Zb, the power ratio, and the fundamental angular frequency.

[0069] Specifically, the leakage inductance value of the main transformer may be determined according to the harmonic order, the fundamental angular frequency, and the first proportional coefficient as follows:

[0070] Determine the leakage inductance of the main transformer based on the following formula:

[0071]

[0072] Among them, α is the first proportional coefficient, ω=ω0h=2πfh, ω0 is the fundamental angular frequency, h is the harmonic order, L m is the leakage inductance of the main transformer, and C2 is the capacitance of the first capacitor.

[0073] It should be noted that for high-frequency harmonic currents, the load-side inductor presents a high impedance, causing most of the harmonic current to flow through the low-impedance capacitor branch, and the load-side current harmonics only account for a portion of the converter current harmonics. If it is assumed that the load voltage does not contain harmonic components, then for harmonics, Figure 4 The grid-side voltage source in can be regarded as a short circuit, so we can get:

[0074]

[0075] If the design requires |i Lm (h)|=α|i L2 (h)|, 0<α<1. It can be seen that after selecting C2, substituting the corresponding angular frequency ω and the first proportional coefficient α, the leakage inductance value Lm of the main transformer can be calculated.

[0076]

[0077] In a specific example, Figure 3 The LCL circuit is the observation object, and we get Figure 4 .

[0078] If there is no capacitor branch, there is only one option for placing the voltage and current sensors on the load side. The PWM rectifier controls the load current and voltage in phase, and the entire system is purely resistive. The reference impedance Zb is:

[0079]

[0080] Where E is the output voltage of the converter after filtering, and P is the active power of the converter.

[0081] The equivalent impedance of the inverter from the grid side is

[0082]

[0083] Among them, U out is the output voltage of the converter after filtering, I Lm , I L2 , I C2 They all represent the vector form of the corresponding variables.

[0084] When the inverter side operates at unity power factor, according to the circuit relationship:

[0085] U con =U out -jω(L2+L m )I L2

[0086]

[0087]

[0088] Among them, U con is the output voltage of the converter before filtering.

[0089] Then we get:

[0090]

[0091] From the above formula, we can see that the grid-side equivalent circuit is a capacitor C2 connected in parallel with the reference impedance, as shown in Figure 5 shown. Figure 5 The per-unit value is as follows:

[0092] z grid =1-jx c2

[0093] Assuming P and Q are the active and reactive power absorbed by the grid-side system, respectively, we can get:

[0094]

[0095] Based on the above formula, C2 can be obtained.

[0096] S120: Constructing a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer.

[0097] The system open-loop transfer function is a system open-loop transfer function using a PIR control method.

[0098] It should be noted that traditional resonant controllers have infinite gain at this resonant order. When a large damping coefficient is added, the error signal is bandpassed, and the resonant controller acts as a bandpass filter. Therefore, the PIR controller is equivalent to adding a bandpass filter to the control link, introducing the bandpassed signal into the modulated wave. Here, it is important to note that the coefficients of the resonant link and the proportional-integral link must be reversed to achieve zero-pole cancellation and suppress the resonant peak.

[0099] Optionally, the system open-loop transfer function is:

[0100]

[0101] Where a = K P , b=2K P ω c +K I +2K R ω c , c=K P ω0 2 +2K I ω c , d = K I ω0 2 , k pwm is the PWM proportional gain, U dc is the DC bus voltage of the on-load tap-changing transformer, U cm is the modulation wave amplitude of the on-load tap-changing transformer, L m is the leakage inductance of the main transformer, L2 is the inductance of the first inductor, C2 is the capacitance of the first capacitor, ω0 is the fundamental angular frequency, K P is the proportionality coefficient, K I is the integral coefficient, K R is the resonance coefficient, ω c is the resonator cutoff frequency.

[0102] In a specific example, the embodiment of the present invention adopts a current control method of inverter current feedback, and the system open-loop transfer function of the inverter current feedback can be obtained as follows:

[0103]

[0104] Among them, G c (s) is the current error regulator, k pwm is the PWM proportional gain, k pwm =U dc / U cm , U dc and U cm are the DC bus voltage and modulation wave amplitude of the on-load tap-changing transformer respectively.

[0105] The traditional dual current loop control is to decompose the current into the dq coordinate system for DC quantity control, and the PI controller can be used to achieve zero static error tracking of the current. However, when the system contains a large resonant peak current, the resonant current is decomposed into a sinusoidal component in the dq coordinate system, and the PI control cannot achieve complete tracking of the sinusoidal error, resulting in the inverter modulation wave containing resonant subvoltage, making the system unstable. The embodiment of the present invention considers adding resonant link control to form a PIR controller, and achieves good tracking of the resonant current through parameter matching, thereby suppressing the resonant peak. Considering that the ideal resonant controller has infinite gain at the resonant frequency, it will have an adverse effect on the stability of the system. It is necessary to add a cutoff frequency to increase its damping, and the PIR controller under quasi-resonance is obtained as follows:

[0106]

[0107] Where: K P , K I , K R are proportional integral and resonance coefficient respectively; w c is the resonator cutoff frequency. The system schematic diagram using PIR control is as follows Figure 6 shown.

[0108] Figure 6 In, G c (s) is the current error regulator, k pwm is the PWM proportional gain, u inv is the inverter voltage before gain, u inv* is the inverter voltage after gain.

[0109] Then the open-loop transfer function of the system is obtained as:

[0110]

[0111] Where a = K P , b=2K P ω c +K I +2K R ω c , c=K P ω0 2 +2K I ω c , d = K I ω0 2 , k pwm is the PWM proportional gain, U dc is the DC bus voltage of the on-load tap-changing transformer, U cm is the modulation wave amplitude of the on-load tap-changing transformer, L mis the leakage inductance of the main transformer, L2 is the inductance of the first inductor, C2 is the capacitance of the first capacitor, ω0 is the fundamental angular frequency, K P is the proportionality coefficient, K I is the integral coefficient, K R is the resonance coefficient, ω c is the resonator cutoff frequency.

[0112] By adjusting the PIR parameters, the resonant sub-zero point of the open-loop transfer function is configured to offset the infinite gain caused by the pole, and then by giving an appropriate cutoff frequency ω c , to achieve the ideal damping coefficient of the system. Take K P =-K R , the resonant frequency of the resonant regulator is the LCL resonant point, then the above formula can be simplified to:

[0113]

[0114] Let the denominator polynomial of the above formula be zero, and the two open-loop poles are obtained from the characteristic equation of the system:

[0115]

[0116] Where, the damping ratio ζ = ω c / ω0. The damping ratio coefficient can be comprehensively considered according to the response time and modulation wave amplitude required by the system, and then the cutoff frequency of the resonant link can be determined.

[0117] The function of the PIR regulator is to perform proportional-integral control on the DC fundamental component and to respond to the sinusoidal error signal caused by the resonant current.

[0118] S130 , determining a cutoff frequency of a resonant link of the on-load tap-changing transformer according to the system open-loop transfer function, a response time of the on-load tap-changing transformer, and an overshoot of the on-load tap-changing transformer.

[0119] It should be noted that the method for determining the cutoff frequency of the resonant link of the on-load tap-changing transformer based on the open-loop transfer function of the system, the response time of the on-load tap-changing transformer and the overshoot of the on-load tap-changing transformer can be: determining the open-loop pole according to the open-loop transfer function of the system, determining the damping ratio according to the open-loop pole, comprehensively determining the damping ratio coefficient based on the response time and modulation wave amplitude required by the system, and then determining the cutoff frequency of the resonant link based on the damping ratio coefficient.

[0120] S140: Perform active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer.

[0121] Specifically, the method of performing active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer is as follows: the on-load tap-changing transformer is actively damped according to the proportional integral resonance coefficient of PIR and the cutoff frequency of the resonant link of the on-load tap-changing transformer.

[0122] The technical solution of this embodiment obtains the circuit parameters of the output filter, the response time of the on-load tap-changing transformer, and the modulation wave amplitude of the on-load tap-changing transformer; constructs a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer; determines the cutoff frequency of the resonant link of the on-load tap-changing transformer according to the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer; and performs active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer, which can offset the infinite gain caused by the pole, achieve an ideal damping coefficient, and suppress the resonance peak.

[0123] Example 2

[0124] Figure 7 This is a schematic diagram of the structure of a filter control device in an on-load tap-changing transformer provided by an embodiment of the present invention. This embodiment is applicable to the case of filter control in an on-load tap-changing transformer. The device can be implemented in software and / or hardware. The device can be integrated into any device that provides filter control function in an on-load tap-changing transformer, such as Figure 7 As shown, the filter control device in the on-load tap-changing transformer specifically includes: an acquisition module 710, a system open-loop transfer function construction module 720, a cutoff frequency determination module 730 of the resonant link of the on-load tap-changing transformer, and an active damping control module 740.

[0125] The acquisition module is used to obtain the circuit parameters of the output filter, the response time of the on-load tap-changing transformer, and the modulation wave amplitude of the on-load tap-changing transformer;

[0126] A system open-loop transfer function construction module, configured to construct a system open-loop transfer function according to circuit parameters of the output filter and control parameters corresponding to the on-load tap-changing transformer;

[0127] A cutoff frequency determination module for the resonant link of the on-load tap-changing transformer, configured to determine the cutoff frequency of the resonant link of the on-load tap-changing transformer based on the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer;

[0128] An active damping control module is used to perform active damping control on the on-load tap-changing transformer according to the cut-off frequency of the resonant link of the on-load tap-changing transformer.

[0129] The above-mentioned product can execute the method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0130] The technical solution of this embodiment obtains the circuit parameters of the output filter, the response time of the on-load tap-changing transformer, and the modulation wave amplitude of the on-load tap-changing transformer; constructs a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer; determines the cutoff frequency of the resonant link of the on-load tap-changing transformer according to the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer; and performs active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer, which can offset the infinite gain caused by the pole, achieve an ideal damping coefficient, and suppress the resonance peak.

[0131] Example 3

[0132] Figure 8 A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0133] like Figure 8 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. Various programs and data required for the operation of the electronic device 10 can also be stored in the RAM 13. The processor 11, ROM 12, and RAM 13 are connected to each other via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0134] Multiple components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0135] The processor 11 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the filter control method in an on-load tap-changing transformer.

[0136] In some embodiments, the filter control method for an on-load tap-changing transformer can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the filter control method for an on-load tap-changing transformer described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to execute the filter control method for an on-load tap-changing transformer in any other appropriate manner (e.g., via firmware).

[0137] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0138] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0139] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0140] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0141] The systems and techniques described herein can be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0142] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0143] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0144] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A filter control method in an on-load tap-changing transformer, characterized in that: The on-load tap-changing transformer includes: a main transformer, an on-load tap-changer, an input filter, an output filter and a converter. The control method includes: Obtaining circuit parameters of the output filter, a response time of the on-load tap-changing transformer, and a modulation wave amplitude of the on-load tap-changing transformer; Constructing a system open-loop transfer function according to the circuit parameters of the output filter and the control parameters corresponding to the on-load tap-changing transformer; Determining a cutoff frequency of a resonant link of the on-load tap-changing transformer according to the open-loop transfer function of the system, a response time of the on-load tap-changing transformer, and an overshoot of the on-load tap-changing transformer; Performing active damping control on the on-load tap-changing transformer according to the cutoff frequency of the resonant link of the on-load tap-changing transformer; The open-loop transfer function of the system is: in, , , , , is the PWM proportional gain, , is the DC bus voltage of the on-load tap-changing transformer, is the modulation wave amplitude of the on-load tap-changing transformer, is the leakage inductance of the main transformer, is the inductance of the first inductor, is the capacitance value of the first capacitor, is the fundamental angular frequency, is the proportionality coefficient, is the integration coefficient, is the resonance coefficient, is the resonator cutoff frequency, is the system open-loop transfer function, is the complex frequency domain variable of the Laplace transform.

2. The method according to claim 1, characterized in that The output filter includes: a leakage inductance of a main transformer, a first capacitor, and a first inductor.

3. The method according to claim 2, characterized in that Obtaining circuit parameters of the output filter, including: Obtaining identification information of the on-load tap-changing transformer; querying a database according to identification information of the on-load tap-changing transformer; If the database contains a leakage inductance value of the main transformer corresponding to the identification information of the on-load tap-changing transformer, the capacitance value of the first capacitor is determined according to the leakage inductance value of the main transformer, the first proportional coefficient, the harmonic order, and the fundamental angular frequency, and the inductance value of the first inductor is determined according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor.

4. The method according to claim 3, characterized in that Also includes: If the leakage inductance value of the main transformer corresponding to the identification information of the on-load tap-changing transformer does not exist in the database, the inductance value of the first inductor is determined according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor, the capacitance value of the first capacitor is determined according to the power ratio, the fundamental angular frequency, the output voltage of the converter after filtering, and the active power of the converter, and the leakage inductance value of the main transformer is determined according to the harmonic order, the fundamental angular frequency, and the first proportional coefficient.

5. The method according to claim 3, characterized in that The inductance value of the first inductor is determined according to the fundamental angular frequency, the output voltage of the converter before filtering, the harmonic order, and the current of the first inductor, including: Determining the amplitude of each order harmonic of the converter output voltage according to the output voltage of the converter before filtering; determining the amplitudes of each harmonic of the converter current according to the current of the first inductor; The inductance value of the first inductor is determined according to the fundamental angular frequency, the amplitudes of each order harmonic of the converter output voltage, the harmonic order, and the amplitudes of each order harmonic of the converter current.

6. The method according to claim 5, characterized in that Determining the inductance value of the first inductor according to the fundamental angular frequency, the amplitudes of each order harmonic of the converter output voltage, the harmonic order, and the amplitudes of each order harmonic of the converter current includes: The inductance of the first inductor is determined based on the following formula: ； in, is the inductance of the first inductor, is the amplitude of each order harmonic of the converter output voltage, is the amplitude of each harmonic of the converter current, is the fundamental angular frequency, is the harmonic order.

7. A filter control device in an on-load tap-changing transformer, characterized in that: The on-load tap-changing transformer includes: a main transformer, an on-load tap-changer, an input filter, an output filter and a converter. The filter control device in the on-load tap-changing transformer includes: An acquisition module is used to acquire circuit parameters of the output filter, a response time of the on-load tap-changing transformer, and a modulation wave amplitude of the on-load tap-changing transformer; A system open-loop transfer function construction module, configured to construct a system open-loop transfer function according to circuit parameters of the output filter and control parameters corresponding to the on-load tap-changing transformer; A cutoff frequency determination module for the resonant link of the on-load tap-changing transformer, configured to determine the cutoff frequency of the resonant link of the on-load tap-changing transformer based on the system open-loop transfer function, the response time of the on-load tap-changing transformer, and the overshoot of the on-load tap-changing transformer; an active damping control module, configured to perform active damping control on the on-load tap-changing transformer according to a cutoff frequency of a resonant link of the on-load tap-changing transformer; The open-loop transfer function of the system is: in, , , , , is the PWM proportional gain, , is the DC bus voltage of the on-load tap-changing transformer, is the modulation wave amplitude of the on-load tap-changing transformer, is the leakage inductance of the main transformer, is the inductance of the first inductor, is the capacitance value of the first capacitor, is the fundamental angular frequency, is the proportionality coefficient, is the integration coefficient, is the resonance coefficient, is the resonator cutoff frequency, is the system open-loop transfer function, is the complex frequency domain variable of the Laplace transform.

8. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the filter control method in the on-load tap-changing transformer according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the filter control method in the on-load tap-changing transformer according to any one of claims 1 to 6 when executed.

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