103 results about "Series compensation" patented technology

Systems and method to minimize conditions that cause sub-synchronous oscillation (SSOs) associated with series compensated transmission grids. The implementations ensures the correct development of methods and systems that can mitigate sub-synchronous oscillation (SSOs) associated with a series compensated transmission grid and enhance the series compensation efficiency. An example implementation is a network-based SSO mitigation technology, and another example implementation is a generator-based SSO mitigation technology. The discovery and example implementations are applicable to series compensated transmission networks with synchronous generators, induction generators, wind turbines, solar photovoltaic generators, charging stations, battery storage systems, high-voltage DC transmission systems, STATCOMs, inverter-based data centers, and other inverter-based resources.

The invention belongs to the technical field of power systems, and particularly relates to a power grid impedance simulation device, a design method and a use method.The design of the device comprises the steps that the types of needed components are determined, and the number of the components and electrical parameter values are obtained according to the actual national standard in combination with the minimum component number criterion; all components are connected according to needs, and a controller is adopted to realize corresponding control so as to support working condition simulation and switching of different short circuit ratios and series compensation degrees; a switch logic control program is set in the controller, so that when the controller receives a power grid working condition switching instruction, switching of working conditions corresponding to the power grid short-circuit ratio and the series compensation degree is achieved by executing the preset switch logic control program. According to the technical scheme, through the integrated design of parameter calculation, hardware topology and logic control, the problems of low test efficiency, poor simulation precision and high cost in the prior art are solved, and an efficient, accurate and economical solution is provided for the adaptability test of the new energy converter under a double-high power system.

The invention relates to the technical field of controllable series compensation, in particular to a power distribution area voltage rapid compensation device and compensation method based on controllable series compensation, and the method comprises the steps: collecting various monitoring data of each phase of each key node of a power distribution area in real time; obtaining each sub-time period of each monitoring data of each phase; acquiring a change correlation value and a deviation change characteristic value of various monitoring data of each phase in each sub-time period; comparing the deviation change characteristic values of various monitoring data between each phase and each of the other phases of the key node where the phase is located so as to obtain a dynamic change factor of the various monitoring data of each phase at each moment and obtain an influence weight and a voltage characteristic value of each phase of each key node at each moment; and compensating the voltage of the power distribution area based on a controllable series compensation technology. According to the method, the trigger angle in the voltage compensation process is accurately determined by accurately evaluating the voltage deviation of each key node, and the accuracy of voltage compensation of the power distribution area is improved.

The present application belongs to the field of flexible AC transmission and distribution and power electronics, and discloses a unified power quality conditioner and method to achieve the goal of power quality management. The device comprises a DC bus and a compensation unit and a regulating unit connected thereto; the compensation unit comprises a series compensation subunit and a parallel compensation subunit; the series compensation subunit is used for compensating the load voltage; the DC bus is used for providing compensation energy for the series compensation subunit; the parallel compensation subunit is used for compensating the load harmonic, three-phase imbalance and reactive current, and also used for providing voltage support for the DC bus and energy for the series compensation subunit; the regulating unit comprises a parallel super capacitor energy storage system and a photovoltaic power generation system; the super capacitor energy storage system comprises a super capacitor and a first DC / DC converter; the photovoltaic power generation system comprises a photovoltaic array and a second DC / DC converter. The present application solves the coupling problem of the series and parallel inverters of the device, and makes the DC side bus voltage stable.

The embodiment of the invention discloses a control method for suppressing subsynchronous oscillation of a doubly-fed fan and related equipment, relates to the technical field of stable control of a power system, and directly estimates subsynchronous frequency based on inherent parameters such as series compensation capacitance reactance, equivalent inductive reactance and power grid synchronous frequency. The influence of the power grid resistance parameter change on the sub-synchronous frequency estimation value is eliminated; quickly locking a spectrum analysis range based on the obtained subsynchronous frequency estimation value; according to the method, the oscillation frequency, namely the subsynchronous resonant frequency, is accurately locked through fast Fourier decomposition of the rotor current in combination with an amplitude comparison strategy in a preset spectral analysis range, and the subsynchronous resonant frequency in a doubly-fed fan rotor side control system is filtered out, so that oscillation suppression is achieved.

The present application discloses a method for suppressing subsynchronous oscillations of a doubly-fed wind turbine and related equipment, belonging to the field of wind power generation technology. The method comprises: when the doubly-fed wind turbine is connected to the power grid via a series compensation capacitor, obtaining a voltage control signal of the doubly-fed wind turbine in a synchronous rotating coordinate system; using a filter to extract the voltage control signal within a specified frequency band, and using a phase shifter to perform phase shift compensation on the signal extracted by the filter with the goal of ensuring that the doubly-fed wind turbine satisfies the positive impedance characteristic within the specified frequency band; performing an inverse Park transform on the voltage control signal after phase shift compensation, and using the voltage control signal after the inverse Park transform to control the three-phase AC power output by the doubly-fed wind turbine. This method can solve the current technical problems of high cost, complex modeling, and difficulty in engineering application when suppressing subsynchronous oscillations of doubly-fed wind turbines.

The present invention relates to the field of wireless power transmission technology, and discloses a highly anti-offset wireless power transmission system with four reconstruction modes, comprising a reconfigurable inverter module, a primary-side compensation network module, a secondary-side compensation network module, and a rectifier filter circuit module; through the coordination of compensation topology reconstruction and parameter optimization design, constant power output within a coupling coefficient variation range of about 620% is achieved, and the secondary-side loop only uses a single capacitor series compensation. The system structure is more compact, simple, and lightweight, and is more in line with actual application requirements. It can achieve constant power output within a coupling coefficient variation range of about 620% at a fixed operating frequency and without the need for additional control hardware or complex mechanical adjustments, only through simple switch tube control.

The invention discloses a power grid operation mode voltage automatic adjustment method and system suitable for different new energy coincidence rates, and belongs to the technical field of power systems. According to the method, series compensation and parallel compensation of a plant station with an out-of-limit bus in a third power flow result are output, a capacitor is automatically input or reactance is automatically quitted from the plant station with the voltage exceeding the lower limit according to the difference between the voltage and the limit voltage, and a reactive power is automatically output from the plant station with the voltage exceeding the upper limit according to the difference between the voltage and the limit voltage. And the capacitor is automatically withdrawn or the reactance is input. According to the invention, under the condition that the voltage cannot be adjusted, surrounding reactive power resources can be automatically adjusted, the terminal voltage of a new energy machine is cooperatively adjusted, and the voltage of a high voltage level can be automatically switched to a target level through series-parallel compensation.

The invention belongs to the field of wireless electric energy transmission, and discloses a three-coil structure constant-current constant-voltage type wireless electric energy transmission system suitable for an office table, the system comprises an electric energy sending unit, a relay unit and a receiving unit, and the relay unit forms a series resonance network through a relay coil L2 and a relay series compensation capacitor C2; the receiving unit consists of a receiving coil L3, a receiving end compensation network, a rectifier D and a battery load R; the input end of the rectifier D is connected with the receiving coil L3, a constant current mode compensation capacitor C3CC and a constant voltage mode compensation capacitor C3CV which can be switched through a switch S are connected in series between the rectifier D and the receiving coil L3, and the output end of the rectifier is connected with a battery load R. The system can realize constant-current and constant-voltage output characteristics meeting battery charging requirements when the equivalent impedance of the battery is changed, and can ensure that the inverter realizes zero-phase-angle switching operation when the equivalent impedance of the battery is changed and the system is subjected to position offset.

An S2G charging station harmonic current detection and UPQC suppression method fusing wavelet transform and an LVQ neural network performs multi-scale decomposition on a current signal by using the wavelet transform, extracts time-frequency characteristics of different frequency bands, realizes real-time detection and classification of harmonic current in combination with the LVQ neural network, suppresses the harmonic current at the charging station side through a UPQC parallel compensation unit, and improves the harmonic current detection and UPQC suppression efficiency. The series compensation unit eliminates power grid side voltage harmonics. According to the method, high-precision harmonic current detection can be realized in the S2G charging station, harmonic current of different frequency bands can be quickly and accurately identified and classified, and amplitude and phase information of the harmonic current can be extracted, so that accurate analysis of the harmonic current is realized; through the dynamic compensation function of the UPQC, the harmonic current of the power grid and the charging station can be effectively suppressed, and the stability of the electric energy quality of the system is ensured. The method has efficient real-time detection and compensation capability, and can significantly reduce the negative influence of harmonic distortion on the power grid and the charging station.

The application discloses a kind of second-order general type fast desaturation controller determination method and system, it is related to engineering system control field, this method includes: determining the saturation gain of actuator in target industrial control system;Using the input-output deviation of actuator, second-order general type fast integral desaturation compensator is constructed;Based on saturation gain, second-order general type fast integral desaturation compensator is equivalent into the desaturation structure of series compensation, and the compensation link and desaturation channel in desaturation structure are determined;Using the linkage relationship of bandwidth PID controller and desaturation bandwidth, the value of desaturation bandwidth in compensation link and desaturation channel is determined, to obtain the second-order general type fast desaturation controller of target industrial control system.The application can realize control while selecting less parameters, and improve the stability of control.

The utility model discloses a low pressure series compensation device relates to the technical field of compensation circuit, including the soft start power supply circuit for controlling starting current slow rise, the surge impact is suppressed, the capacitive reactive power output for the dynamic regulation series capacitor, the low pressure reactive power compensation circuit of compensation inductive load's reactive power shortage, the voltage detection circuit for real -time tracking circuit voltage fluctuation, generates the voltage feedback signal required for compensation control. The utility model discloses through the voltage detection circuit, thereby through the accurate detection of resistance voltage dividing network and operational amplifier IC1, realizes real -time monitoring and signal conditioning to the grid voltage, ensures that compensation system can accurately obtain voltage variation information, provides reliable data support for reactive power compensation control.

A static synchronous series compensation system and method, the scheme includes: a primary circuit installed on a high potential platform and a secondary circuit installed in a control protection room; the high potential platform is connected with a power transmission line at the same potential; the primary circuit is connected in series with the power transmission line to compensate the voltage of the power transmission line; the secondary circuit is connected with the primary circuit, and compensation instructions are issued to the primary circuit according to the voltage loss value of the power transmission line. The static synchronous series compensation system in the scheme does not need a series transformer or only needs a low insulation grade series transformer, greatly reduces the insulation design difficulty of the series transformer, reduces the device cost, reduces the equipment weight, reduces the equipment cost, and greatly reduces the occupied area. In the scheme, the high potential platform is connected with the power transmission line at the same potential, and the primary circuit is installed on the high potential platform, which reduces the energy loss of the primary circuit caused by corona discharge and the electromagnetic interference of the adjacent equipment.

The present invention discloses an autonomous coreless transformer and a refined design method thereof. The transformer comprises an autonomous voltage source, a circular winding bobbin, a primary winding, a secondary winding, a primary series compensation capacitor, a secondary series compensation capacitor, an uncontrolled rectifier module, an output filter capacitor, and a load resistor. The secondary winding is wound around the center of the circular winding bobbin, and the primary winding is evenly distributed on both sides of the secondary winding. Adjusting the number of turns and gap between the primary and secondary windings can control the transformer parameters. The present invention achieves refined design of the autonomous coreless transformer parameters by combining winding structure design with voltage deviation compensation.

The invention discloses a method and device for calculating the defect rate of series compensation secondary equipment under different operation years, a medium and equipment. The method comprises the following steps: extracting a series compensation secondary equipment set and a series compensation secondary equipment defect set which meet a preset statistical condition; dividing the operating age limit into a plurality of continuous operating age limit units based on the division granularity of the operating age limit; traversing the series compensation secondary equipment in the series compensation secondary equipment set, determining operation age limit units covered by the life cycle of the series compensation secondary equipment according to the commissioning time and the back operation time of the series compensation secondary equipment, and adding 1 to an equipment number counter corresponding to each covered operation age limit unit; traversing equipment defects in the series compensation secondary equipment defect set, determining an operation age limit unit to which the equipment defects belong according to the operation age limit of the corresponding series compensation secondary equipment when the defects occur, and adding 1 to a defect number counter corresponding to the operation age limit unit; and for each operating age limit unit, calculating the defect rate of the operating age limit unit according to the corresponding defect number and equipment number.

The invention discloses a hybrid distribution transformer power electronic module capacity configuration method for load prediction. The method comprises the steps that the capacity of a series compensation module is calculated based on a target area load prediction value so as to represent the power processing capacity needed by voltage compensation; when the capacity of the parallel compensation module is determined, the capacity value of the series compensation module is multiplexed, so that a load fluctuation compensation task is cooperatively borne, and the capacity of the parallel compensation module is equal to the sum of the following two parts: a) the product of the capacity of the transformer in the transformer area and a fixed proportionality coefficient is used for representing a reactive power compensation demand proportion; b) the capacity value of the series compensation module; and selecting the series compensation module and the parallel compensation module of which the actual power processing capacity is not less than the calculation capacity.

The invention discloses a subsynchronous / supersynchronous oscillation characteristic-maintained wind power plant equivalent modeling method, which comprises the following steps of: constructing a frequency domain impedance model based on a doubly-fed fan series compensation grid-connected system; based on the frequency domain impedance model, the influence of the wind speed and the grid-connected distance on the frequency domain impedance characteristic is analyzed, and a dynamic grouping result of the doubly-fed wind turbine generator is obtained through a clustering algorithm; adopting a capacity weighting method to obtain parameters of an equivalent wind turbine generator; determining reserved nodes and eliminated nodes of the system according to a dynamic grouping result of the wind turbine generator, and obtaining equivalent parameters of the current collection network by adopting an REI static equivalence method; and establishing a doubly-fed fan series compensation grid-connected system simulation model based on the simulation platform, comparing the steady-state power flow, the dynamic response and the sub / super-synchronous oscillation characteristics before and after equivalence, and analyzing the equivalence precision. The new energy station dynamic equivalence method provided by the invention has good equivalence precision in steady-state power flow and dynamic response characteristics, and provides an accurate model basis for analyzing the stability of a high-proportion new energy power system.

The invention discloses a series compensation platform secondary equipment shielding effect analysis method and system under strong electromagnetic interference, and the method comprises the steps: carrying out the multi-conductor modeling of a series compensation platform and a bus, and carrying out the finite element modeling of the primary equipment of the series compensation platform, thereby building a rapid transient overvoltage simulation model of the primary equipment of the series compensation platform; performing simulation to obtain rapid transient overvoltage between the low-voltage bus and the high-potential platform at the position of the secondary equipment measurement box under the set overvoltage condition; finite element modeling is carried out on the secondary equipment, a rapid transient overvoltage signal between a low-voltage bus and a high-potential platform is applied to the modeling, electric field distribution under the set overvoltage condition is obtained through simulation, and the shielding effectiveness of a measurement box of the secondary equipment under different frequencies is calculated; changing the materials of the secondary equipment to analyze the electromagnetic shielding effectiveness of different materials under the set overvoltage condition; according to the invention, effective anti-electromagnetic interference measures can be provided effectively, and the anti-interference performance of the secondary equipment of the high-voltage series compensation platform is improved.

The application discloses a hybrid distribution transformer power electronic module capacity configuration method for load prediction, and the capacity of a series compensation module is calculated based on a target area load prediction value to represent power processing capacity required for voltage compensation; when the capacity of a parallel compensation module is determined, the capacity value of the series compensation module is reused to realize collaborative assumption of a load fluctuation compensation task, so that the capacity of the parallel compensation module is equal to the sum of the following two parts: a) the product of the capacity of a transformer in a transformer area and a fixed proportionality coefficient, to represent the proportion of reactive power compensation demand; and b) the capacity value of the series compensation module; and the series compensation module and the parallel compensation module with actual power processing capacity not less than the calculated capacity are selected.

According to the controllable series compensation transformer through-flow automatic compensation circuit and compensation method, a main adjustment capacitor group, a fine adjustment capacitor group, a fine adjustment inductor group, a main adjustment contactor contact, a fine adjustment contactor contact, an anti-parallel thyristor contact, a protection contactor contact, a choke inductor, a voltage transformer 1, a control module and a voltage transformer 2 are connected to obtain input test parameters; and setting capacitance and inductance in the main adjustment capacitor group, the fine adjustment capacitor group and the fine adjustment inductor group, selecting a test mode, calculating the compensation capacitance, and performing capacitor switching based on a capacitor gear switching method according to the calculated compensation capacitance. Capacitance compensation can be accurately carried out on the transformer, the power factor of the power supply in the test process is improved, and the working efficiency of the test power supply is improved.

The invention provides a power distribution network non-power-outage loop-closing power transfer device and a control method. The device comprises a loop-closing power transfer controller, and a direct-current voltage stabilizing circuit, a series compensation circuit and a load switching circuit which are connected in sequence, the direct-current voltage stabilizing circuit serves as direct-current input of the series compensation circuit and is used for providing voltage support; the series compensation circuit is connected in series between the original supply bus and the transfer supply bus during working and is used for compensating the voltage difference between the original supply bus and the transfer supply bus; the load switching circuit is used for controlling the connection and disconnection of the series compensation circuit between the original supply bus and the transfer supply bus; and the closed-loop transfer controller is used for performing signal acquisition on the original supply bus, the transfer bus, the direct-current voltage stabilizing circuit and the series compensation circuit, and controlling the closed-loop transfer device to complete closed-loop transfer between the original supply bus and the transfer bus. The series compensation circuit does not need to bear all loads on an original supply bus, and only needs to be designed according to the power required for generating the compensation voltage, so that the capacity of the required power electronic converter is reduced.

The invention relates to the technical field of wireless power transmission, and particularly discloses a two-constant-voltage power supply wireless charging circuit structure suitable for illumination application, which comprises a transmitting side and a receiving side, the transmitting side comprises a direct current input power supply UD, an inverter circuit, a transmitting side series compensation inductor L1, a transmitting side series compensation capacitor C1, a transmitting side parallel compensation inductor L2, a transmitting side parallel compensation capacitor C2, a transmitting side series compensation capacitor C3 and a transmitting coil LP; and the receiving side comprises a receiving coil LS, a receiving side series compensation capacitor C4, a receiving side parallel compensation capacitor C5, a receiving side parallel compensation inductor L3, a receiving side series compensation inductor L4, a rectifying circuit, a filter capacitor CF and a load RB. The circuit structure has the beneficial effects that the circuit structure effectively solves the problem that constant voltage output of various specifications cannot be realized in a traditional wireless power transmission system, and can meet the requirement that an illumination system needs different illumination intensities in different environments.

The present application relates to the technical field of eddy current pulse thermography detection, and specifically discloses an eddy current pulse thermography detection system based on LCC resonance topology and a control method thereof, aiming at the problems of resonance frequency drift and excitation current fluctuation caused by the change of lift-off height of the traditional eddy current pulse thermography excitation source, the present application adopts LCC resonance topology, sets compensation inductance, parallel compensation capacitor and series compensation capacitor to meet specific parameter conditions, decouples the excitation coil current from the lift-off height and keeps it constant, and at the same time ensures that the system realizes soft switching in the full load range. On this basis, a voltage closed-loop control strategy is further introduced, the real-time lift-off height is calculated, and the output voltage of the full-bridge inverter is adjusted accordingly to realize constant power output and stable temperature rise of the tested piece under the change of lift-off height. The present application effectively overcomes the influence of the change of lift-off height on the consistency of the detection result, and improves the reliability and on-site operation flexibility of the system.

The invention discloses a wireless electric energy transmission compensation topological structure with constant voltage output and a control method, and relates to the technical field of wireless electric energy transmission. The wireless electric energy transmission compensation topological structure with the constant voltage output mainly comprises a direct current power supply, an inverter circuit, a primary side transmitting coil, a secondary side receiving coil, a secondary side series compensation capacitor, a secondary side parallel compensation capacitor, a rectification filter circuit and a load, wherein the inverter circuit is used for converting output direct current of the direct current power supply into high-frequency alternating current. By implementing the wireless power transmission compensation topological structure with constant voltage output and the control method provided by the invention, a primary side structure can be simplified, multi-path integration of a transmitting end is facilitated, the system cost is reduced, load-independent constant voltage output is realized, the inverter loss is reduced, and the transmission efficiency is improved.

The application provides a wide-range on-load voltage regulation voltage compensation control method and system, and an AC / DC / AC converter is connected to the output of an on-load voltage regulation transformer. The converter mainly comprises a parallel side and a series side, and the output of the series side converter is connected to a series transformer. Output voltage regulation is combined with on-load voltage regulation distribution transformer gear adjustment and converter series compensation. Converter capacity configuration considers voltage compensation range, three-phase imbalance compensation, reactive power compensation, thermal effect caused by harmonic compensation and maximum current stress of the converter output. The series side converter output voltage compensation adopts a positive and negative sequence separation control algorithm. The scheme can realize wide-range output voltage stepless compensation regulation, can flexibly limit the current inner loop of the series side converter, avoids equipment overload, and improves equipment reliability.

The invention relates to the technical field of new energy grid connection, and discloses a double-fed wind power plant subsynchronous oscillation suppression device and method based on GCSC-SSRDC. The bottleneck problems of insufficient robustness and poor adaptability of an existing suppression scheme in complex actual engineering can be solved to a certain extent. The device comprises a gating series capacitor GCSC used for replacing a fixed series compensation capacitor and providing a fixed capacitive reactance compensation line inductive reactance, a power dispatching controller used for obtaining a power signal of a power transmission line and outputting a fundamental frequency compensation reactance instruction after processing the power signal through a first-order low-pass filter, and a subsynchronous resonance damping controller SSRDC used for obtaining a current signal of the power transmission line and outputting a fundamental frequency compensation reactance instruction after processing the power signal through a second-order low-pass filter. The control signal generation module is used for superposing the fundamental frequency compensation reactance instruction and the additional reactance instruction and then converting the superposed fundamental frequency compensation reactance instruction and additional reactance instruction into a turn-off pulse signal of a gate control series capacitor switching device through an amplitude limiting, table lookup and pulse generation unit; and suppression of subsynchronous oscillation is realized.

The application discloses a power distribution network non-stop load transfer control method and system based on series compensation, solves the problems of loop closing transient impact, user short-time power failure and the like. The application gives a topology structure of the non-stop load transfer system, introduces the working principle of the system, utilizes the voltage amplitude and phase angle compensation function provided by the series compensation, realizes seamless loop closing control, and further realizes load smooth transfer control by using impedance compensation function. The above method can not only realize that the loop closing moment is not affected by voltage and current impact, the transfer process is stable, and the non-stop load transfer, but also expands the application range of loop closing transfer power, and improves the safety and reliability of loop closing transfer power.

This invention relates to the field of power equipment condition monitoring technology, and discloses an online monitoring and evaluation device and method for series compensation capacitors. The method includes: acquiring operating signals and extracting steady-state operating characteristics and transient characteristic parameters; combining historical cumulative fatigue damage, calculating the dynamic frequency-varying equivalent series resistance modulated by the damage positive feedback effect, and substituting it into the thermal differential equation to iteratively calculate the dynamic hot spot temperature sequence; for transient events, constructing a cross-coupling term characterizing the synergistic effect of electrodynamics and thermomechanical softening, and calculating the high-frequency equivalent partial discharge; performing thermomechanical softening correction on the transient overvoltage peak to obtain the thermomechanical equivalent transient stress, and dynamically updating the electro-thermal-mechanical coupled cumulative fatigue damage by combining real-time dynamic hot spot temperature and high-frequency equivalent partial discharge; finally outputting a health status index. This invention integrates the time-varying evolution of thermal stress and the multi-physics field transient synergistic damage mechanism, significantly improving the accuracy of equipment damage quantification.

The invention discloses a subsynchronous oscillation stability region division method for a steam turbine generator grid-connected system, and belongs to the technical field of power system stability analysis. The invention aims to solve the problem that the existing method cannot realize the stability region division of the steam turbine generator under different operation conditions. Comprising the steps of obtaining a state equation of the steam turbine generator and processing to obtain generalized sequence impedance; decoupling is carried out to obtain positive sequence port impedance; constructing a two-dimensional parameterized model of the grid-side impedance based on the power grid short-circuit ratio and the series compensation degree; performing frequency domain comparison on the positive sequence port impedance and the network side impedance, analyzing the intersection frequency and the phase margin of the positive sequence port impedance and the network side impedance based on amplitude-frequency and phase-frequency characteristics, and dividing the subsynchronous oscillation state of the grid-connected system into a stable state, a critical stable state and an unstable state by combining an impedance stability criterion; and determining a stable state region, a critical stable state region and an unstable state region by combining the two-dimensional parameter plane. The method is used for evaluating the stability boundary of the system under different operation conditions.

The embodiment of the application discloses a control method for inhibiting subsynchronous oscillation of a doubly-fed fan and related equipment, relates to the technical field of stability control of power systems, and directly estimates a subsynchronous frequency based on inherent parameters such as series compensation capacitance reactance, equivalent inductance and grid synchronous frequency, so that the influence of grid resistance parameter change on the estimated value of the subsynchronous frequency is excluded; based on the estimated value of the subsynchronous frequency obtained above, a frequency spectrum analysis range is quickly locked; through fast Fourier decomposition of rotor current and in combination with an amplitude comparison strategy in the preset frequency spectrum analysis range, an oscillation frequency, namely a subsynchronous resonance frequency, is accurately locked, and the subsynchronous resonance frequency in the rotor side control system of the doubly-fed fan is filtered out, so that oscillation is inhibited.