377 results about "Signal injection" patented technology

The invention relates to the technical field of cable positioning, in particular to a one-way grounding fault positioning method based on a signal injection method. The method comprises the following steps: installing an impedance detection unit at a grounding knife switch of a transformer substation, and injecting a controllable AC signal into a power transmission line through a built-in injection coil to enable the line to be in an open circuit state; collecting the injected current signal and performing frequency enhancement to extract the amplitude and phase of a target frequency component; zero-sequence impedance is calculated based on the injection voltage and current, and the zero-sequence impedance is compared with a preset impedance model to judge single-phase grounding; and when a fault is detected, determining a fault distance, a tower position and a grounding phase according to an impedance difference matching result, thereby realizing accurate positioning. According to the invention, by injecting the controllable AC signal into the power transmission line and combining frequency enhancement, phase self-calibration and impedance difference matching analysis, high-sensitivity detection, high-stability signal extraction and high-precision positioning of the single-phase earth fault are realized.

The invention relates to the technical field of power cable fault detection and positioning, in particular to a middle and high voltage cable insulation defect live detection and positioning method, which comprises the following steps: step 1, injecting a composite detection signal into a cable conductor through a signal injection device; 2, arranging signal acquisition devices at a plurality of preset point positions of the cable; step 3, carrying out adaptive processing on the acquired response signal; step 4, extracting insulation defect features from the response signals after adaptive processing; step 5, based on the extracted insulation defect features, classifying defect types by using a pattern recognition algorithm, and calculating defect positions based on a signal propagation time difference principle; and 6, outputting a defect identification and positioning result to a monitoring system, verifying, and if the deviation between the positioning result and historical data exceeds a threshold value, re-executing the steps 1 to 5. By combining a multi-point synchronous measurement technology and a precise space-time analysis method, the position where the defect occurs can be positioned more accurately.

The invention specifically relates to a standardized fuse fault monitoring and diagnosis system, and relates to the technical field of power system protection equipment monitoring. A signal processing and impedance spectrum calculation module; an intelligent diagnosis and state evaluation module; and a benchmark management and personalized tracking module. According to the invention, controllable micro test signals are actively injected to obtain frequency domain impedance fingerprints, and accurate capture of microscopic degradation is realized; non-intrusive coupling and signal injection are adopted, the topology of a main loop does not need to be changed, the inherent protection characteristic of the fuse is guaranteed, and power frequency interference can be penetrated; the recognition amount of budding faults such as contact oxidation and melt corrosion is improved in advance, and power failure accidents caused by fault expansion are avoided.

The invention relates to an electrostatic vibrating diaphragm automobile audio which is mainly used for an electric vehicle and can compensate vehicle-mounted electromagnetic interference audio and solve the problem of electromagnetic interference of a motor PWM switch and rotating speed harmonics on an audio system. The electrostatic diaphragm automobile sound system comprises an electrostatic diaphragm loudspeaker and an interference feature extraction module, the rotating speed of a motor and the PWM frequency are obtained through a CAN bus, and a dynamic interference feature set is analyzed and extracted through adaptive window length FFT; the EMI quantification module is used for calculating an electromagnetic pollution index at a frequency band of 8kHz-20kHz, and triggering compensation when the electromagnetic pollution index exceeds a threshold value of-40dB; the dynamic notch compensation module is used for generating an inversion signal; according to the double-loop feedback control module, the amplitude is adjusted through PID of an inner loop, and the phase is optimized through gradient descent of an outer loop so as to minimize THD. The method comprises five steps of signal acquisition, feature extraction, interference quantification, dynamic compensation and signal injection. Interference frequency drift can be accurately tracked, a tone quality MOS value is improved after compensation, and an over-compensation risk is avoided.

The invention relates to the technical field of power system protection, in particular to an underground power distribution network single-phase grounding protection system and method based on a signal injection method. The system comprises a signal acquisition module, a measurement and control protection module and an online monitoring module. According to the invention, by injecting the independent direct current signal and combining a zero-sequence fundamental wave time sequence identification algorithm and a traveling wave distance measurement method, rapid detection, high-precision positioning and selective protection of the single-phase earth fault of the underground low-voltage power distribution network are realized, and the method is suitable for complex environments such as coal mines and metal mines; through insulation value on-line monitoring and electric leakage protection, the ground insulation value level of a line is reflected to the voltage change of an additional direct current signal and a reactor neutral point. A zero-sequence fundamental wave time sequence identification model is adopted for electric leakage fault judgment so as to judge the fault type. By outputting a relay signal, on-off control is performed on a protected branch, so that a fault line can be quickly cut off when a fault occurs, and equipment and a bus are protected from being damaged by the fault.

The invention discloses a permanent magnet synchronous motor sensorless control method based on a dynamic position error. A transition stage is provided, per-unit estimation position errors between a first position error signal obtained based on a high-frequency signal injection method and a second position error signal obtained based on a sliding mode observer are compared, an optimal switching speed point is dynamically determined, smooth fusion is carried out on the two position errors by using a nonlinear weighting function, and the optimal switching speed point is obtained. And finally, the estimated position and rotating speed are obtained through a phase-locked loop. And finally, position tracking is carried out by adopting different error signals according to the estimated rotating speed. According to the method, the problem of estimation value pulsation and jump caused by the fact that a traditional method depends on fixed experience switching points is solved, smooth and self-adaptive switching of the two estimation methods in the full-speed domain range is achieved, the control precision and operation stability of the system are remarkably improved, the structure is simple, and engineering implementation is easy.

The invention provides a mining motor no-load and load characteristic test analysis method and system, and relates to the field of intelligent image analysis, a Hall array sensor is arranged on a motor stator tooth portion to collect air-gap magnetic field distribution data, and a high-frequency signal injection method and a wavelet singular value decomposition technology are combined, so that the load characteristic of a mining motor is obtained. The air gap magnetic field distortion degree and the air gap dynamic eccentricity index are accurately calculated, and meanwhile a load dynamic compensation coefficient is generated to correct the motor output torque. Therefore, the dynamic characteristics of the motor in the no-load and load states can be comprehensively reflected, the accuracy of the load capacity evaluation of the mining motor is improved, and potential problems in the operation of the motor can be found in time, so that the performance of the motor is optimized, the service life of the motor is prolonged, and the safety and reliability of mining production are improved.

The invention discloses an on-line insulation monitoring system and method for a national railway vehicle, and relates to the technical field of on-line insulation monitoring, and the system comprises a detection signal injection module which is used for injecting a preset broadband active detection signal, and synchronously collecting a response signal set transmitted through a vehicle body grounding network; the fingerprint feature construction module is used for constructing network fingerprint features in a current insulation state; the spatial distribution atlas acquisition module is used for carrying out inversion calculation to obtain an admittance spatial distribution atlas of the whole vehicle; and the insulation abnormal area identification module is used for identifying an insulation abnormal area. According to the invention, the technical problems of long troubleshooting time and poor accuracy caused by incapability of online real-time monitoring of the insulation state of the vehicle body grounding network of the national railway vehicle and low abnormal area positioning precision in the prior art are solved, and online monitoring of the insulation state of the vehicle body grounding network of the national railway vehicle and accurate positioning of the abnormal area are realized. And the efficiency and the accuracy of insulation fault checking are improved.

The invention provides an automobile electronic control unit fuzzy testing method based on partial code coverage rate feedback and a computer, and belongs to the technical field of automobile electronic control unit code testing. The computer performs static analysis on source codes of the automobile electronic control unit, identifies inevitable execution blocks and conditional execution blocks, performs selective instrumentation on the conditional execution blocks, and inserts coverage rate recording instructions of the conditional execution blocks. And the computer source code is loaded into the automobile electronic control unit, and a test input signal is generated through the fuzzy test engine and is injected into the automobile electronic control unit. In the process of executing the program by the automobile electronic control unit, recording the coverage condition of the condition execution block to a bitmap in the memory; the computer reads the coverage rate data of the condition execution block through the debugger every time a complete execution cycle is completed; and the fuzzy test engine adjusts the input generation strategy according to the coverage rate data feedback of the condition execution block and tests again. According to the method, the automobile electronic control unit source code fuzzy test coverage condition is efficiently collected.

The invention relates to the technical field of fault detection, in particular to an electronic component fault management method and system. The method comprises the following steps: collecting real-time data and constructing a real-time fault monitoring data set; reading historical data and constructing a historical reference data set; comparing the real-time fault monitoring data set with the historical reference data set item by item in a corresponding time window to obtain a drift amplitude, and mapping according to the drift amplitude to generate a reverse excitation amplitude instruction; a reverse current signal according to the reverse excitation amplitude instruction is injected into the loop node to be measured, and a Hall null drift amount is determined according to Hall output; outputting an electronic disturbance quantity based on the Hall null drift quantity; therefore, through dynamic data cooperation and an active excitation response mechanism, the problems of missing detection recessive degradation, misjudgment transient interference and single diagnosis dimension of traditional fault management are solved, and the hidden danger recognition precision and the protection reliability are remarkably improved.

The invention belongs to the technical field of nuclear power, and particularly relates to a ground capacitance measurement method based on series capacitance and high-frequency signal injection. In order to solve the problem that a traditional signal injection method cannot accurately calculate the ground capacitance level of a power distribution network, the invention provides a ground capacitance measurement method based on a series capacitor and high-frequency signal injection. The leakage inductance of the voltage transformer is accurately measured by injecting the high-frequency signal, so that a resonance point is convenient to find during frequency sweeping, and the resonance point measured during frequency sweeping is more accurate.

The invention discloses an electric arc dynamic suppression method for hot plugging of an electric meter connector, relates to the technical field of electric energy metering equipment, and aims to solve the problems of electric arc generation, overproof metering error and the like caused by passive protection and lack of dynamic cooperative control in the prior art. The core of the method is that gap distance and power grid voltage phase signals are acquired in real time through a microcontroller, and the plugging speed, the signal injection and the position fine adjustment are dynamically regulated and controlled in three stages of pre-contact, low-current transition and full connection; and a machine learning model is combined to optimize a parameter threshold value, a redundancy safety mechanism and a multi-phase electric meter cooperative control strategy, so that double management and control of arc peak energy and metering errors are realized. The method can actively inhibit arc generation, avoid connector ablation and insulation deterioration, guarantee metering continuity and accuracy, adapt to complex power grid and environment working conditions, and meet the precision requirement of the intelligent electric meter.

The invention discloses a permanent magnet synchronous motor turn-to-turn short circuit fault diagnosis method based on a high-frequency negative-sequence component, and the method comprises the steps: obtaining a high-frequency voltage injection signal according to the three-phase current of a motor, obtaining a high-frequency current signal through space vector pulse width modulation, injecting the high-frequency current signal into the motor, obtaining the three-phase voltage and three-phase current of the current motor, and extracting a high-frequency component in the three-phase voltage and three-phase current; high-frequency negative-sequence voltage and high-frequency negative-sequence current are obtained according to the extracted high-frequency components, and fault features are constructed; comparing the fault feature with a fault threshold value, judging that the permanent magnet synchronous motor is healthy if the fault feature is smaller than the fault threshold value, and judging that the permanent magnet synchronous motor is faulty if the fault feature is larger than or equal to the fault threshold value. According to the method, extra detection hardware is not needed, real-time detection and positioning of the turn-to-turn short circuit fault can be realized by using the negative sequence component of the motor in the high-frequency domain in the servo operation state of the permanent magnet synchronous motor, and the method has relatively high applicability and robustness.

The invention discloses a TBM cutterhead main drive intelligent decision-making method and system, and belongs to the technical field of cutterhead drive control. Unified regulation and control and target torque distribution of a driving system are realized by constructing a master-slave type multi-driving-unit collaborative architecture; a fault is identified by monitoring a current signal, a voltage vector is reconstructed according to the fault type, and continuous and stable output under the fault is ensured; a disturbance observation method based on an integral sliding mode is provided, and control deviation caused by system disturbance and parameter changes is dynamically estimated and compensated; an MPTA control strategy of high-frequency virtual signal injection is designed, and utilization of reluctance torque and stable tracking of an MTPA working point are achieved; the torque output capacity of a fault unit and the torque margin of a healthy unit are comprehensively considered, a load distribution strategy is planned, and the overall loading capacity and the operation life of the driving system are improved.

The invention provides a multi-port coupled cable signal abnormity determination method and a related device, and the method comprises the steps: controlling N signal injection modules to input a coupling sweep frequency signal to a to-be-detected cable through the implementation of the embodiment of the invention; receiving M second signals and M standard reflection coefficients from the cable to be detected; determining M third signals based on the M second signals and the M standard reflection coefficients; and determining a fusion signal spectrum under the frequency fk based on the M third signals, wherein the fusion signal spectrum is used for determining a signal abnormal condition of the to-be-detected cable. Therefore, multi-port coupling and synchronous injection are realized at the head end of the cable, and the excitation energy and the signal-to-noise ratio of the broadband impedance test are remarkably improved through superposition and data fusion of multi-path signal energy, so that high-precision positioning and reliable evaluation of the latent defect of the cable are realized under a complex working condition.

The invention discloses a real-time damage detection device for a communication receiver under strong electromagnetic pulse impact, and belongs to the field of electromagnetic compatibility. According to the device, different signal injection modes are adopted, the injection power and the injection duration of signals are adjusted, an injection experiment of high-power electromagnetic pulses is carried out, and the damage condition of the communication receiver under strong electromagnetic pulse attack in a complex electromagnetic environment is simulated through the working state of the most sensitive first-stage low noise amplifier of the receiver, so that the reliability of the communication receiver is improved. And real-time damage detection is carried out, and exploration about damage conditions is carried out, so that timely maintenance and further protection of the communication receiver in a complex environment are facilitated. The device can simulate the impact effect of strong electromagnetic pulses on the communication receiver, comprehensively monitor the working state of the communication receiver in real time and record the damage condition, provide core support for rapid positioning and isolation of fault equipment, and remarkably shorten the communication link repair time.

The invention provides a DC system fault positioning method based on an improved variable frequency signal injection method, and the method comprises the steps: firstly, injecting AC signals of different frequencies into a bus of a DC system, and collecting the response current of each branch after the AC signals are injected; then, screening the response current through a signal processing algorithm to obtain a response characteristic quantity, and calculating a response ratio of each branch according to the response characteristic quantity; and finally, based on the response ratio of each branch, judging the branch with the fault through a numerical comparison method. According to the method, the frequency conversion signals are injected at the two ends, branch feedback detection and corresponding signal algorithms are combined, and the feedback result is processed by utilizing ratios, so that the operation steps are simplified, the requirements of detection equipment are reduced, the influence of interference signals on the final judgment result can be reduced through algorithm combination processing, and the overall detection accuracy of the method is improved.

The invention provides a permanent magnet synchronous motor sensorless control method based on self-adaptive high-frequency signal injection, and the method comprises the steps: carrying out the online calculation of the amplitude of an optimal high-frequency injection signal through building a relation model of the amplitude of a pulsating square wave high-frequency voltage signal, the total harmonic distortion rate of motor current, and the fundamental current; generating a pulsating square wave high-frequency voltage signal with the optimal amplitude; a current envelope containing rotor position information is extracted from high-frequency response current through a high-pass filtering and synchronous demodulation technology, and rotor position and rotating speed information is extracted by adopting a phase-locked loop structure and fed back to a closed-loop control system. According to the method, the current harmonic content is strictly limited within the preset range by dynamically adjusting the amplitude of the injection signal, high-frequency noise caused by a traditional fixed amplitude injection method is reduced, quick response and robustness of a system during load sudden change are ensured, and the contradiction that noise and precision are irreconcilable in a traditional method is effectively solved.

The invention provides an industrial and commercial energy storage cabinet which comprises a cabinet body, a battery cabin and an electrical cabin which are isolated from each other are arranged in the cabinet body, a battery management system with a dynamic impedance detection function is integrated in the energy storage cabinet, and a liquid cooling heat management unit, a fire-fighting host and a plurality of groups of battery packs arranged at intervals are sequentially arranged in the battery cabin from bottom to top. Each group of battery packs is provided with a sound early warning device, a battery management system with a dynamic impedance detection function is integrated on each battery pack, and the real-time detection of the dynamic impedance of the battery is realized by utilizing a high-frequency alternating current signal injection and dynamic impedance spectroscopy analysis technology; a sound early warning device which is arranged along with a battery pack array is combined to capture mechanical characteristic sound in the initial stage of thermal runaway, and a fire-fighting detector which is arranged in a battery cabinet and used for detecting hydrogen, carbon monoxide, volatile organic compounds, smoke concentration and temperature is arranged, so that a multi-dimensional monitoring network of'dynamic impedance-characteristic sound-environmental parameters' is realized.

The invention discloses a deceptive signal injection and control method for an MEMS inertial sensor. The invention relates to the technical field of safety protection of MEMS (micro-electromechanical system) inertial sensors, and in the method, a resonant frequency interference signal subjected to amplitude modulation (AM) and phase modulation (PM) is injected into a target sensor to simulate a Coriolis force effect generated by real inertial input (such as angular velocity), so that a physically static MEMS device outputs preset erroneous motion data which seems legal, and the erroneous motion data is detected. And therefore, cheating on an upper-layer control system (such as an automatic driving attitude control unit) is realized. According to the method, by accurately controlling modulation parameters (such as modulation depth and phase offset) and a signal injection time sequence, a false inertial measurement value with high concealment and credibility can be generated, and the method is suitable for scenes such as sensor safety test, anti-interference algorithm verification and fault simulation.

The invention discloses a direct-current bus harmonic suppression method and system for photovoltaic grid connection in an industrial park, and relates to the technical field of harmonic suppression of a direct-current bus of a photovoltaic power supply and improvement of the power quality of a power distribution network, and the method comprises the steps: generating required direct-current output through series voltage boosting and parallel current increasing, constructing a photovoltaic power generation unit, and adding a DC-DC converter, based on MPPT, a three-layer control method is adopted to track the maximum power point and control a DC-DC converter switching device; for a DC-DC converter and a DC-AC inverter, system mathematical modeling and theoretical analysis are carried out, and a DC side current is deduced; and based on the collected DC side current, extracting a specific harmonic component and generating a reverse compensation signal, and injecting the signal into a corresponding DC bus control link for harmonic suppression. According to the method, the DC bus voltage ripple coefficient is reduced, harmonic waves generated by MPPT, phase-locked loop disturbance and switch modulation are suppressed, the total harmonic distortion rate of the output current of the inverter can be reduced, and the stability margin of the system under the weak power grid condition is improved.

The application discloses an online permanent magnet flux identification method of a permanent magnet synchronous motor considering cross coupling effect and belongs to the permanent magnet flux identification technology of the permanent magnet synchronous motor. The application aims at solving the problem that the existing permanent magnet synchronous motor flux identification method does not consider the cross coupling influence of the motor, thereby causing the error of the flux observation result to be large. The application comprises the following steps: under the online stable working condition of the motor, injecting a sinusoidal current signal into the dq axis of the motor to realize three-phase direct current signal injection; calculating the motor stator resistance; injecting two groups of direct current bias voltage into the d-axis of the motor through the current loop, establishing three motor voltage equations, and then obtaining two motor voltage difference equations which eliminate the flux terms; solving to obtain the motor d-axis self-inductance L d and the motor dq-axis mutual inductance L dq ; establishing the dq-axis voltage equation considering the cross coupling, calculating the motor permanent magnet flux based on the motor stator resistance, the motor d-axis self-inductance L d and the motor dq-axis mutual inductance L dq . The application is used for the online identification of the permanent magnet flux of the permanent magnet synchronous motor.

A kind of maximum torque current ratio-based full-order flux linkage observer virtual voltage signal generation method belongs to motor position sensorless control technical field.The present application aims at the problem that the amplitude of existing virtual voltage signal injection based on full-order flux linkage observer is extremely difficult to adjust,which cannot realize stable operation under different load conditions at zero speed.The present application includes the following steps: constructing full-order flux linkage observer based on the voltage equation of built-in permanent magnet synchronous motor under estimated rotating shaft system;linearizing decoupling the flux linkage error dynamic equation of full-order flux linkage observer at local point to obtain the mathematical expression relationship between position estimation error of full-order flux linkage observer and virtual voltage signal;then establishing the relationship between position estimation error and torque of built-in permanent magnet synchronous motor;setting position estimation error as maximum torque current ratio angle,calculating to obtain the injection coefficient of virtual voltage signal;generating virtual voltage signal based on the injection coefficient.The present application can realize parameter tuning of motor position observer.

The invention relates to the technical field of loop detection, and particularly provides a line error account analysis method, system and device and a medium, and the method comprises the steps: configuring a composite signal feature comprising a unique frequency hopping sequence, a pseudo-random code and time slot division planning for each loop after a host is connected with each line loop, and injecting a signal into a power line according to a plan; the slave machine detects a line signal at a point to be detected in a non-contact manner, and analyzes a frequency hopping sequence and pseudo-random code features to form a detection fingerprint; and performing multi-dimensional comparison on the fingerprint and the characteristics configured by the host, and judging the matching relationship between the to-be-detected point and the specific loop. According to the invention, through the design and joint analysis of the time, frequency and code three-dimensional orthogonal signals, the anti-interference capability, the multi-loop identification precision and the weak signal detection reliability are significantly improved.

The application discloses a TBM cutter head main drive intelligent decision method and system, and belongs to the technical field of cutter head drive control. By constructing a master-slave type multi-drive unit collaborative architecture, unified regulation and control and target torque distribution of the drive system are realized; by monitoring current signals to identify faults, voltage vectors are reconstructed according to fault types, and continuous and stable output under faults is ensured; a disturbance observation method based on integral sliding mode is proposed, control deviation caused by system disturbance and parameter change is dynamically estimated and compensated; an MPTA control strategy of high-frequency virtual signal injection is designed, utilization of reluctance torque and stable tracking of the MTPA operating point are realized; the torque output capacity of the fault unit and the torque margin of the healthy unit are considered as a whole, a load distribution strategy is planned, and the overall load carrying capacity and operating life of the drive system are improved.

The application relates to the technical field of power system monitoring and fault diagnosis, and discloses a corrosion degree detection method based on a mine double-loop power supply line. The method comprises the following steps: injecting a dynamic frequency modulated micro-amplitude excitation signal into the double loop; acquiring an interference characteristic spectrum and generating an anti-aliasing filter parameter through an environmental noise sensing module; separating high-frequency transient and low-frequency steady-state components by using wavelet packet decomposition and empirical mode decomposition dual-channel preprocessing; combining a deep time sequence encoder embedded with an electrochemical model prior to extract corrosion features, and reconstructing a pure corrosion signal through an interference suppression decoder driven by an attention mechanism; and finally outputting a quantitative index by a corrosion rate inversion model and triggering a graded early warning. The system comprises a signal injection unit, a noise sensing module, a dual-channel preprocessing unit, a deep encoding-decoding network and an early warning module. The application significantly improves the accuracy and robustness of corrosion detection through multi-scale feature decoupling, physical constraint modeling and noise adaptive suppression.

The invention relates to a circuit (100) for providing a current source with a defined operating point, in particular a defined zero point, comprising - comprising an operational amplifier (OP), ◯ a first entrance (10), ◯ a second entrance (20), ◯ an output (30) which can be connected to a load (V), wherein the output (30) is configured to output a current (I) with a defined operating point, - a first signal generator (MC1) connected to the first input (10) to feed a first signal (PWM1) into the first input (10), - a second signal generator (MC2) connected to the second input (20) to feed a second signal (PWM2) into the second input (20), - wherein the first signal (PWM1) and the second signal (PWM2) have at least temporarily an identical pulse width in order to generate a defined operating point at the output (30). Furthermore, the invention relates to a system comprising such a circuit (100).

The invention provides a motor control method and system based on parameter identification, a vehicle-mounted refrigerator and a computer program product. The method comprises the following steps of: injecting a high-frequency sinusoidal voltage signal into an output end of a current loop when a motor runs, and identifying a current motor parameter; and controlling the motor based on the current motor parameter. Therefore, the technical problem that vibration and noise are introduced into a system while high-precision motor parameter identification is achieved through high-frequency sinusoidal voltage signal injection is solved; the current changed actual value of the motor parameter is correctly and accurately identified / recognized to accurately calculate and control the motor, so that the conditions of low efficiency and shutdown caused by misalignment of control due to deviation between the controller and the actual value when the controller is controlled based on the preset value of the motor are effectively avoided; the operation reliability and stability of equipment such as the compressor can be improved under extreme working conditions, and the user experience is improved.

The application discloses a modulation method and device for suppressing common-mode voltage, a storage medium and a motor, wherein the method comprises the following steps: acquiring a DC bus voltage and a three-phase voltage reference signal; generating a random integer, and constructing a limited random zero sequence signal according to the random integer, the DC bus voltage and the three-phase voltage reference signal; injecting the limited random zero sequence signal into the three-phase voltage reference signal, acquiring a three-phase voltage output modulation signal, and controlling the motor according to the three-phase voltage output modulation signal, so as to actively suppress the common-mode voltage. Thus, by injecting a specifically designed random zero sequence voltage, the average switching frequency is randomized, the common-mode voltage spectrum is effectively scattered, and the system control performance and reliability are considered at the same time while suppressing the electromagnetic interference peak.

The application discloses a high-frequency injection positionless control method for a cascade H-bridge power supply permanent magnet motor, which separately configures one H-bridge module of each phase of a cascade H-bridge converter into a square wave output mode, configures the remaining H-bridge modules of each phase of the cascade H-bridge converter into a conventional modulation mode of carrier phase shift, uses rotation transformation to extract motor rotor position information and position bias information, designs a moving average filtering algorithm based on the characteristics of high sampling rate of the cascade H-bridge to eliminate the influence of harmonic voltage in the injected square wave signal, and then uses a phase-locked loop technology to obtain motor rotor position observation results, so as to realize positionless control. The application raises the upper limit of the signal injection frequency of the cascade H-bridge motor system from half of the switching frequency to the switching frequency, is helpful for the signal separation link involved in the positionless control, can reduce the disturbance caused by the injected high-frequency signal, improve the signal-to-noise ratio and accuracy of the motor rotor position observation, and improve the operation performance of the positionless control.