3461 results about "Power electronics" patented technology

The invention discloses a power supply real-time compensation technology and application based on digital signal processing, and relates to the technical field of power electronics, and the power supply real-time compensation technology comprises a split-phase parallel processing architecture: a three-phase independently configured DSP core, each core integration comprises a real-time harmonic detection module, a dynamic sliding window FFT-RT algorithm is adopted, and the window length is adjustable in a set range; the bandwidth of the self-adaptive variable parameter filter can be dynamically adjusted in a set range; the FPGA coprocessor is specially used for PWM generation; an input stage of the harmonic prediction and decomposition module is synchronously acquired by a multi-source sensor; the processing layer comprises an improved VMD decomposition unit and a variational mode decomposition order; the edge prediction network is used for deploying a lightweight LSTM model, embedding a DSP core and predicting a harmonic spectrum in a future short period; and the multi-target dynamic optimization layer is used for setting a dynamic weight distributor and performing real-time adjustment according to the load sudden change rate. According to the invention, through split-phase parallel architecture, harmonic prediction and dynamic optimization, the response speed, multi-target cooperation and reliability improvement in the field of power supply real-time compensation are realized.

The invention relates to the technical field of power electronics, in particular to a voltage ripple suppression and compensation method for a multi-output AC-DC switching power supply, and the method comprises the steps: obtaining the real-time voltage ripple signal of each AC-DC output channel and the working parameters of the switching power supply, and the working parameters comprise the switching frequency, the duty ratio, the inductance and capacitance parameters and the load current; inputting the real-time voltage ripple signal and the working parameters of the switching power supply into a preset coupling interference model, and generating ripple coupling characteristics between AC-DC output channels; determining a ripple suppression compensation coefficient through the ripple coupling characteristics; and based on the ripple suppression compensation coefficient and a preset PWM control signal, adjusting the output voltage of the switching power supply to suppress the ripple, thereby breaking through the limitation of a traditional method on independent processing of a single channel, and fundamentally solving the problem of a ripple suppression blind area caused by cross interference between channels.

The invention relates to the technical field of power electronics, in particular to a photovoltaic off-grid inverter control method and system, and the method comprises the following steps: applying a test signal to identify an output interaction characteristic parameter, predicting the power generation power through combining with weather and attenuation, calculating the power fluctuation, and adjusting a current control parameter set. And calculating voltage and reactive power compensation parameters to generate an inverter control instruction, and combining a temperature load prediction trend to adjust a power allowable value to obtain a predictive power calibration coefficient. According to the invention, by analyzing the output interaction characteristics, enhancing the perception capability of the inverter to the actual operation environment, combining with the prediction of the photovoltaic power generation amount, realizing the prediction and influence evaluation of the power fluctuation, improving the adaptive adjustment capability of the current control parameters, improving the output voltage and reactive power control precision by utilizing the interaction characteristics, and optimizing the electric energy quality; and through thermal management of multi-point temperature and load prediction, the operation safety is improved, the service life of equipment is prolonged, and the operation performance of the photovoltaic off-grid system in a complex environment is improved.

The invention discloses a multi-mode CNN / Transform image defect diagnosis tracking decision-making method, and belongs to the field of power electronic industry detection. According to the method, defect position multi-modal data of different batches, process stages and equipment are collected, after space-time alignment and image enhancement preprocessing and alignment are conducted, features are extracted through position coding, a CNN shallow network and ResNet-18, the features are fused into multi-modal feature vectors in combination with weights, a detection model is obtained through CNN / Transform model training, defect diagnosis and tracking decision making are achieved, and the defect diagnosis and tracking decision making efficiency is improved. The problems of precise detection, positioning, diagnosis tracking and decision-making of internal tiny component changes and structural defects of electronic products and local and overall multi-mode defects of single electric power are solved. The detection accuracy is improved by 20%, the diagnosis accuracy is more than 98.5%, the defect tracking error is less than 5%, the decision-making efficiency is improved by 40%, and the defect prediction capability is improved by 22%.

The invention relates to the technical field of power electronics, and discloses a soft switch of a high-frequency switch transformer and a distributed control method and system thereof, and the method comprises the steps: achieving the precise synchronization of nodes through the construction of a ring topology network, combining the monitoring of multiple physical quantities with the collaborative optimization of parameters, dynamically adjusting the parameters of a resonant network and a driving time sequence, and achieving the precise synchronization of the nodes. A zero-voltage switching state is maintained, and electromagnetic interference is suppressed by adopting the composite optimization model; the system comprises a network initialization module, a multi-physical-quantity monitoring module, a space-time synchronization control module, a resonance parameter adjustment module, an electromagnetic optimization decision module, a dynamic adjustment module and a parameter evolution module. The stability of the soft switch is improved through a distributed network and time-space synchronization, and the loss is reduced by adopting a dynamic optimization algorithm; constructing an electromagnetic interference optimization model to enhance compatibility; performing multi-parameter fusion and weight distribution to optimize dynamic response; the reliability is improved through a high-precision protocol and coevolution; and the tensor product framework realizes multi-dimensional intelligent cooperative control.

The invention relates to the technical field of power electronics, in particular to a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace. Comprising the following steps: acquiring three-phase voltage, current, power factor, harmonic content and temperature parameters of the low-voltage side of the submerged arc furnace through a sensor network; the load fluctuation of the submerged arc furnace in the future 1-5 minutes is predicted based on a deep learning algorithm, and a compensation demand pre-judgment value is generated; according to a load prediction result and a real-time working condition, performing dynamic switching from three modes of fixed compensation, grouped switching and continuous adjustment; harmonic component dynamic tracking compensation is carried out by combining an active power filter (APF) and a static var generator (SVG); the system overvoltage, overcurrent and temperature parameters are monitored in real time, and a grading protection mechanism is triggered and fed back to the compensation strategy adjusting module. The invention provides a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace so as to improve the response speed of the system, prolong the service life of equipment and guarantee the electric energy quality of a power grid.

The invention discloses an intelligent operation and maintenance fault early warning method for a rail transit variable-frequency power supply, and relates to the technical field of power electronics and intelligent operation and maintenance, and the method comprises the following steps: setting a multi-point synchronous collection device to carry out the high-precision real-time collection of voltage and current signals of a variable-frequency power supply system, and carrying out the digital coding processing of data; and performing frequency domain analysis on the acquired voltage and current signals by using a preset spectrum analysis algorithm, and extracting harmonic amplitudes and phase characteristic parameters of different orders. According to the invention, through high-precision synchronous acquisition and spectrum analysis, rapid and accurate identification of harmonic abnormity is realized; a machine learning model and dynamic threshold adjustment are fused, and the adaptability and intelligent recognition capability of the system to fault modes under multiple working conditions are enhanced; and a trend prediction and graphical early warning platform is introduced, so that the fault risk is pre-judged in advance and visually responded, and the operation and maintenance efficiency and the operation safety of the rail transit power supply system are remarkably improved.

The invention relates to the technical field of power electronics, in particular to a filter equivalent circuit design simulation system suitable for an energy storage converter, which comprises a main circuit topology unit, a control strategy unit, a parameter optimization and design unit, a simulation engine unit and a performance evaluation unit, wherein the main circuit topology unit is used for building a filter equivalent circuit topology of the energy storage converter and configuring passive element parameters of an inductor, a capacitor and a resistor. According to the method, automatic high-robustness optimization of filter parameters is realized through genetic algorithm-particle swarm hybrid optimization, multi-objective collaborative optimization and digital twinning auxiliary optimization, and a'design-optimization-verification-iteration 'closed loop is formed by combining dynamic working condition evaluation, reliability modeling and artificial intelligence auxiliary analysis, so that the method has the advantages of high robustness and high robustness. The harmonic suppression capability, efficiency and long-term operation reliability of the filter are remarkably improved, the design period is shortened, and the development cost is reduced.

The invention provides a wide-voltage self-adaptive closed-loop vector swimming pool pump anti-interference method, and relates to the technical field of motor control and power electronics, and the method comprises the steps: collecting three-phase power supply voltage fluctuation characteristic parameters and motor operation state parameters in real time; performing amplitude compensation and phase synchronization correction on the voltage parameter based on the dynamic voltage compensation factor; a closed-loop vector anti-interference control model is constructed, and model parameters are adjusted in real time through a vector immunity coefficient; dynamically correcting control output by adopting a multivariable feedback regulation mechanism; executing an anti-interference instruction and synchronously updating PWM modulation parameters, and verifying a control effect in combination with hardware-in-the-loop simulation; and parameter self-learning optimization is realized through a genetic algorithm. The dynamic anti-interference capability under power grid voltage fluctuation and harmonic interference is improved, intelligent thermal management is realized through a temperature-voltage-current multi-dimensional coupling model, full-life-cycle self-adaptive optimization of the system is guaranteed, and the problems of compensation lag, insufficient harmonic suppression and poor long-term stability are effectively solved.

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

The invention provides a fault ride-through control method and system for a network-forming converter, and relates to the technical field of power electronics. The fault ride-through control method of the network construction type converter comprises the following steps: determining a real-time virtual impedance value corresponding to a control loop based on a virtual admittance control module; in response to the fact that the real-time virtual impedance value is larger than or equal to the reference virtual impedance value of the control loop, transient current output by the network-building type converter is adjusted based on first-stage current limiting, and steady-state current output by the network-building type converter is adjusted based on second-stage current limiting; calculating an active power proportionality coefficient based on the real-time parameter and the reference parameter; calculating a target active power reference value according to the active power proportionality coefficient and the reference active power reference value; and executing power control based on the target active power reference value, and adjusting the output voltage of the network-forming converter. According to the method, when the power grid breaks down, the grid-forming type converter can have the functions of current limiting and transient synchronization stability improving at the same time.

The invention relates to the technical field of power electronics, in particular to a transient synchronization stability analysis method of a grid-connected system based on a grid-connected converter and a grid-constructed converter connected in parallel with the grid-connected converter and related equipment. According to the invention, through the conservative estimation of the work of the non-integrable interaction term of the grid-connected system with the grid-following converter and the grid-constructing converter connected in parallel, the power angle stability upper boundary of the grid-following converter and the grid-constructing converter is determined; and according to the obtained power angle stability upper boundary, the transient synchronization stability of the grid-connected system of the grid-following converter parallel connection network-constructing converter is judged, and the reliability and stability of the grid-connected system based on the grid-following converter parallel connection network-constructing converter are improved.

The invention provides an electric energy quality compensation method and system based on power electronics, and relates to the technical field of power grid dispatching, and the method comprises the steps: collecting the voltage, current, harmonic content, reactive power, three-phase unbalance degree and other real-time multi-mode data of a power grid, and extracting key frequency spectrum features through wavelet transform denoising and windowing interpolation Fourier transform; and constructing a power quality feature vector. A self-adaptive fuzzy logic algorithm and power grid operation parameters are combined, a threshold value of a power quality index is dynamically adjusted, a multi-stage optimization strategy is divided based on the number of standard-exceeding indexes and importance analysis, and a dynamic compensation priority and a compensation strategy are generated. An improved particle swarm optimization algorithm is introduced, an inertia weight is dynamically adjusted, a constraint penalty function is introduced, output parameters of a power electronic compensation device are optimized, and effective compensation of power quality is realized by taking minimization of total active loss as a target.

The invention discloses an accurate zero crossing point control method for a built-in relay of a large-current electric energy meter, which relates to the technical field of power electronics and intelligent metering and comprises the following steps of: receiving a power grid voltage digital signal, determining a voltage zero crossing point by comparing symbol changes of adjacent sampling values, establishing a phase corresponding relation between voltage and current, and calculating a current phase corresponding relation; generating current zero crossing point prediction data; when a relay switching instruction is received, the specific moment of the next current zero crossing point is calculated, and the control signal sending moment is determined; a relay driving control signal is sent, the actual action completion moment of the relay is collected, the deviation from the expected zero crossing moment is calculated, and the mechanical action delay time parameter of the relay is corrected. By predicting the current zero-crossing time and considering the mechanical action delay characteristic of the relay, accurate switching of the built-in relay at the actual current zero-crossing point is achieved, meanwhile, the self-adaptive adjusting capacity is achieved, the arc energy during large-current switching is reduced, the service life of the relay is prolonged, and the reliability of the electric energy meter is improved.

The invention relates to a power electronics and energy storage technology, and aims to provide a medium-voltage uninterruptible power supply system based on cascade super-capacitance energy storage and a control method. According to the system, a cascade super-capacitance energy storage module with a three-phase structure is connected between an isolation reactor and a load side switch through a filter reactor and is used for stabilizing the voltage of a load bus; according to the invention, operations of adaptive power reference calculation, voltage phase control and voltage amplitude stable control are carried out; according to the method, the over-capacitance wide voltage operation characteristic is fully considered, and the control on the over-capacitance charging and discharging process is adaptively adjusted according to the power grid fault state and the over-capacitance voltage deviation, so that the system can provide the required power support when the fault occurs, stable energy supplementation is performed after recovery, the risks of over-capacitance voltage out-of-limit and the like are favorably avoided, and the system reliability is improved. And the effectiveness of energy management and the stability of the system are improved. And during a power grid fault period, the load voltage is recovered to be close to a rated value in a short time, voltage drop and overshoot are reduced, and the response speed and the voltage supporting capability of the system are enhanced.

A thermal management system defines a thermal management system flowpath to provide a flow of a fluid to an electric machine and a power electronics assembly electrically connected to the electric machine. The thermal management system includes a first heat exchanger thermally connected to the thermal management system flowpath and to the electric machine, and a second heat exchanger thermally connected to the thermal management system flowpath downstream of the first heat exchanger. The second heat exchanger is thermally connected to the power electronics assembly.

The invention provides a circulation power optimization method and system for a three-phase dual-active bridge, and relates to the field of power electronics, the method comprises the following steps: determining an optimal backflow modulation strategy set corresponding to a hybrid modulation group, the hybrid modulation group comprising triangular wave modulation, trapezoidal modulation, synchronous modulation and extended phase shift modulation, the optimal backflow modulation strategy set corresponding to the hybrid modulation group comprises modulation modes and degree-of-freedom relationships corresponding to different transmission power per unit value ranges in different voltage conversion ratio ranges; determining a degree of freedom and power relationship set corresponding to the hybrid modulation group, wherein the relationship set comprises a relationship between the degree of freedom and power of different transmission power per unit values corresponding to each mode; the phase shift angle, the primary side duty ratio and the secondary side duty ratio are determined by combining the real-time voltage conversion ratio and the real-time virtual power per unit value, operation of the three-phase dual-active bridge is controlled, and the method has the advantages of reducing complexity and improving portability and efficiency.

The invention relates to the technical field of power electronics, in particular to an inverter load feed-forward compensation method and system based on dynamic hysteresis regulation. The method comprises the following steps: acquiring an instantaneous load current signal of an inverter system; wherein when the load current suddenly changes, the bus voltage on the direct current bus fluctuates; performing low-pass filtering on the instantaneous load current signal to extract a direct current component of the load current; determining a dynamic hysteresis limit value according to the instantaneous load current signal, the direct current component and the amplitude adjustment coefficient; comparing the instantaneous load current signal with a historical current feed-forward signal, updating the historical current feed-forward signal according to a comparison result and a dynamic hysteresis limit value, taking the updated historical feed-forward current signal as an updated feed-forward current signal of the current control period, generating a compensation current based on the updated feed-forward current signal, and outputting the compensation current to the current control period. And the compensation current is applied to the corresponding direct-current bus so as to suppress bus voltage fluctuation caused by load abrupt change.

The invention discloses a high-precision power supply output correction method based on a digital pre-distortion technology, and relates to the technical field of power electronics, and the method comprises the steps: integrating an electricity-heat-magnetism real-time combined observer, and inputting parameters including a power supply output voltage, a current, a power device junction temperature, a magnetic element surface temperature, an environment temperature, and an input voltage ripple; using a hierarchical memory depth pre-distortion compensator to generate an anti-phase pre-distortion signal containing long time domain thermal constant compensation and short time domain capacitance energy storage compensation based on modeling engine output; based on a double-ring adaptive updating module, an inner ring updates electrical parameters, including on resistance and dead time, by taking a switching period as a reference, and an outer ring updates thermomagnetic parameters, including thermal resistance and a magnetic core saturation point, in a minute-level period; and the DAC is connected in series with a pre-distortion signal output end through an anti-interference execution channel, and comprises a noise shaping DAC and a driving stage for delay matching. According to the invention, through an electric-thermal-magnetic three-field combined observation architecture, the limitation of traditional single physical field monitoring is broken through.

The invention discloses a feedback type programmable alternating current source load integrated test system, and belongs to the technical field of power electronics. A feedback type programmable alternating current source load integrated test system comprises an alternating current power supply module, an alternating current load module, an energy feedback module, a control module and a test module. The system solves the problems that an existing test system can only provide a single power supply or load function, and excess energy cannot be effectively recycled in the test process, and through cooperative work of the alternating current power supply module, the load module and the energy feedback module, the test efficiency is improved, and the test cost is reduced. Programmable output of an alternating-current power supply, flexible simulation of load characteristics and efficient feedback of redundant electric energy are achieved, the flexibility and the resource utilization rate of the test are improved, the optimal design of the control module comprises the functions of data acquisition, control optimization, fault diagnosis and the like, the real-time performance, stability and reliability of the system are ensured, and the test efficiency is improved. And the load change and the fault condition can be quickly responded.

The invention relates to the field of new energy technology and power electronics, and discloses a photovoltaic diesel generator energy storage hybrid off-grid and grid-connected household energy storage system, which comprises a data acquisition and state monitoring module for acquiring photovoltaic, diesel generator, energy storage, load and commercial power states in real time and generating system state parameters; the central control and decision module generates a control strategy containing an operation mode and an energy scheduling instruction; the energy flow and conversion execution module executes energy conversion and flow; the seamless switching control module realizes non-impact switching between modes; the self-adaptive safety protection module dynamically adjusts protection parameters; and the emergency response and recovery module executes black start and active recovery in an emergency state. According to the invention, through the unified central control and decision-making module, photovoltaic, diesel generator, energy storage and commercial power scheduling logics are integrated to form a collaborative energy management core, and the system can carry out global optimization on energy flow in grid-connected and off-grid modes according to a preset priority principle.

The invention belongs to the technical field of power electronics of power supply or power distribution, and provides a control method of a three-phase four-wire inverter, a controller and an inversion control system. A first control component is generated by using a phase angle, an inversion side three-phase current sampling value and a proportional integral compensator; a second control component and a third control component are generated by using a power grid voltage angular frequency, a neutral line current sampling value, a repetitive controller and a proportional resonance controller, the three control components are combined to control an inverter power switch tube, a proportional integral compensator is still adopted, the algorithm is simple, parameters are easy to design, and the reliability is high. And meanwhile, a repetitive-proportional resonance (RC-PR) composite controller is utilized to realize suppression of neutral line fundamental wave and harmonic current, and the method has faster dynamic response to load abrupt change, so that optimization of dynamic performance and steady-state performance is realized.

The invention discloses a remote real-time monitoring and fault early warning method for a power supply operation state, and relates to the technical field of power electronics and energy management, and the method comprises the steps: collecting the temperature data of a key part of a power supply through an optical fiber Bragg grating sensor array, and analyzing the wavelength offset; electrical parameters are collected through a differential MEMS current / voltage sensor, and a permalloy / ferrite composite shielding layer is arranged in the sensor; collecting a mechanical vibration signal through a piezoelectric ceramic vibration sensor; for device data from different manufacturers, Modbus and CAN heterogeneous protocols are matched and analyzed through a regular expression, and the Modbus and CAN heterogeneous protocols are converted into a unified RDF triple format; inputting temperature, current and vibration data into a space-time alignment module, and constructing a semantic mapping relation by adopting an ontology; calculating a sensor confidence coefficient weight, and performing weighted fusion to generate an equipment health index; operating a lightweight LSTM model at an edge node, and detecting current harmonic and vibration resonance frequency band abnormity in real time; cOMSOL multi-physical field simulation is combined at the cloud end, and the evaporation rate of the capacitor electrolyte is predicted.

The invention relates to the technical field of power electronics, in particular to a multi-level converter midpoint voltage dynamic balance control method, which comprises the following steps: acquiring positive bus voltage and negative bus voltage, and calculating deviation voltage of a DC side midpoint based on the positive bus voltage and the negative bus voltage; on the basis of the positive bus voltage, the negative bus voltage and the calculated deviation voltage of the direct current side midpoint, the duty ratio in the current switching period is calculated by combining the obtained balance bridge current, the obtained balance bridge inductance value and the switching period; determining the duty ratio of upper and lower tubes of the balance bridge according to the comparison result of the deviation voltage and preset positive and negative threshold values; and carrying out carrier wave comparison based on the determined duty ratio of the upper and lower tubes of the balance bridge, generating a PWM signal and driving the upper and lower tubes of the balance bridge. According to the invention, the requirements of high responsiveness and high precision of the multi-level converter on the neutral-point voltage balance performance under the dynamic operation condition can be met.

The invention discloses an IGBT driver fault prediction method and a safety system, and relates to the technical field of power electronics, and the method comprises the steps: constructing a dynamic causal reasoning matrix based on degradation characteristics, and carrying out the reverse reasoning of an accidental fault mode of an IGBT driver through the dynamic causal reasoning matrix; establishing a multi-stage fault prediction model based on the accidental fault mode of the IGBT driver, and predicting the fault occurrence frequency of each life cycle stage of the IGBT driver by using the multi-stage fault prediction model; and identifying a vulnerable element in the IGBT driver based on the fault occurrence frequency, performing fault tracing analysis on the vulnerable element, and optimizing the multi-stage fault prediction model according to a tracing analysis result. According to the method, the causal structure model with the dynamic evolution ability and the causal tracing ability is constructed, the search space of the causal relationship is effectively compressed, and the accuracy and expression ability of the causal path are improved.

The invention relates to the technical field of power electronics and power system control, and discloses an intelligent control method and system for a multi-network converter, and the method comprises the steps: collecting the frequency deviation, the power change rate and the voltage amplitude of a power grid in real time, carrying out the filtering and feature extraction, and analyzing the coupling relation, thereby obtaining the parameter coupling strength. And if the intensity exceeds the threshold value, an inertia adjusting signal is generated through a fuzzy logic controller. And calculating a deviation correction value by combining the state evaluation response performance of the converter, and generating an optimization instruction by fusing the frequency deviation. And solving a voltage stability threshold based on the instruction, updating a coupling index, and issuing and executing after verification. And finally, updating the fuzzy rule base by adopting neural network iterative learning according to feedback data, and forming an inertia support frame with self-learning capability. According to the method, the inertia response speed and the operation stability of the multi-network converter system under high-proportion new energy access can be effectively improved, and adaptive cooperative control is realized.

The invention provides a reconfigurable series-parallel connection network type converter with high overcurrent capacity and a construction method, and belongs to the technical field of power electronic directional power converters. Comprising the following steps of: respectively connecting two corresponding ports of two asymmetric half-bridge modules, symmetric half-bridge modules or H-bridge modules through two bridge type bidirectional switches or reverse series bidirectional switches, and connecting a group of two non-corresponding ports of the modules through a third bridge type bidirectional switch or reverse series bidirectional switch; according to the converter example, two corresponding ports of two H-bridge modules are connected through two bridge type bidirectional switches respectively, and a group of two non-corresponding ports of the two H-bridge modules are connected through a third bridge type bidirectional switch; on the basis that the number of modules is not increased, the overcurrent capacity of the grid-forming type converter is remarkably improved, and the saturation problem of magnetic elements such as a power semiconductor device and a filter inductor is avoided; the system is modularized, simple in structure, malleable and easy to standardize.

The invention belongs to the technical field of power electronics, and relates to an energy feedback high-power-factor air conditioner compressor driving system. Comprising a direct-current bus, a direct-current bus electrolytic capacitor, a motor driving circuit, a shutdown energy feedback circuit, a permanent magnet synchronous motor and a motor control module, wherein the two ends of the direct-current bus electrolytic capacitor are connected with the positive electrode and the negative electrode of the direct-current bus respectively; in the energy feedback control module for driving the combined switch device in the shutdown energy feedback circuit, the motor driving circuit and the shutdown energy feedback circuit, the second connecting end I of each phase of bridge arm is connected with the positive electrode of the direct-current bus, and the second connecting end II of each phase of bridge arm is connected with the negative electrode of the direct-current bus; the first connecting end of the phase bridge arm of the shutdown energy feedback circuit is connected with the phase power grid voltage through the phase filter inductor. The method can maintain the stability of the DC bus voltage, and reduces the influence of the power grid voltage fluctuation and the air conditioner compressor load fluctuation.

The invention discloses a construction method and a modulation method of a three-port multi-frequency MMC topology based on bridge arm multiplexing, and relates to the technical field of power electronics. The construction method comprises the steps that sub-modules of a traditional double-bridge-arm MMC are integrated and optimized into a three-bridge-arm structure through a current conversion branch, independent energy interaction of three ports is achieved through an auxiliary bridge arm, multi-frequency operation modes of power frequency, frequency division, direct current and the like are supported at the same time, and therefore the utilization rate of the bridge arm sub-modules is increased, and the energy utilization rate of the MMC is increased. And the overall size and the manufacturing cost of the converter are reduced. Based on three-port multi-frequency coordination control and power balance requirements, a modulation method of the topological structure is provided, a multi-frequency coordination modulation strategy is adopted, frequency offset is performed through an auxiliary bridge arm to reduce cross interference of port frequency, and output waveform quality is improved through multi-objective optimized capacitor voltage balance control. And meanwhile, direct-current side faults are effectively eliminated by means of the auxiliary bridge arm.

The invention relates to the technical field of power electronics, in particular to a direct-current charging pile insulation monitoring method and system, and the method comprises the following steps: monitoring the voltage deviation between a branch and a bus in real time, adjusting a measurement compensation parameter, correcting a branch insulation resistance measurement value, recognizing leakage current drift, positioning a leakage branch, triggering relay control, and sending alarm information. And generating a charging pile monitoring record. According to the method, the branch voltage deviation trend and the voltage compensation parameters are combined, the branch voltage measurement consistency is improved, the insulation resistance fluctuation is utilized to compare and correct the observation error, the measurement precision is optimized, the current deviation compensation in the no-load state is adopted to eliminate the zero drift interference of the sensor, and the measurement accuracy is improved. A current jump amplitude and a voltage direction are combined to identify an electric leakage branch, positioning accuracy is enhanced, a relay control and event information linkage mode is used, alarm response and equipment state records form a closed loop, and real-time performance and integrity of system monitoring are improved.