337 results about "Power electronics converters" patented technology

The invention provides an impedance scanning device based on network side voltage dynamic compensation under a three-phase voltage imbalance working condition, and relates to the technical field of new energy station power electronic converter topology and control, the device comprises a three-phase rectifier, a direct current bus capacitor, an inverter, a voltage compensation device, a frequency sweeping device, a circuit breaker and a series transformer part, the three-phase rectifier is connected in series with inverters of the voltage compensation device and the frequency sweep device, a secondary side of a series transformer of the voltage compensation device is connected in series with a network side, a secondary side of a series transformer of the frequency sweep device is connected in series with a grid-connected point, and a primary side of the series transformer is connected to the inverters and is coupled to a secondary side of the series transformer; according to the device, the power grid side voltage is rectified through the voltage compensation unit and is compensated to the grid side after being subjected to single-stage inversion transformation, voltage compensation is achieved through the energy of a power grid when the voltage is unbalanced, and an external energy source or an interference source does not need to be introduced. After compensation, the accuracy of the frequency sweeping result is obviously improved.

The invention relates to a multi-energy collaborative intelligent micro-grid control method, device and equipment and a medium. According to the method, a micro-grid frequency signal is collected in real time, the change rate of the micro-grid frequency signal is calculated, the inertia requirement of a system is accurately evaluated, the maximum virtual inertia capable of being provided by each unit is dynamically calculated in combination with the physical characteristics and operation constraints of each energy unit, and the system requirement and the unit capacity are dynamically matched through grey correlation analysis to generate an optimal distribution scheme. And then the special control models of all the units are driven to generate differentiated power regulation instructions, and finally power support is cooperatively executed through the power electronic converter, so that accurate matching and efficient cooperation of multi-energy virtual inertia capability are realized, the frequency stability of a high-proportion new energy power grid is remarkably enhanced, and the system performance is improved. The problems of resource allocation mismatch, poor control adaptability and the like in a traditional method are effectively avoided, and the dynamic safety of the system is guaranteed under the complex operation working condition.

The invention discloses a cooperative control system for an input-series output-parallel dual-active-bridge inverter, and relates to the technical field of power electronic converter control, an input voltage equalizing control IVSC loop is set for m-1 DAB sub-modules, and input voltage equalization of the DAB sub-modules is realized by adjusting phase shift angles of the sub-modules; an output voltage control OVC loop is set for the output DC bus voltage of the whole ISOP-DAB system to stabilize the DC bus voltage, a PIR controller is adopted in the OVC loop, and the resonant frequency is set to be twice of the fundamental frequency of the AC side, so that selective high gain is provided at the position, the frequency doubling fluctuation of the DC bus voltage is inhibited, and the frequency doubling fluctuation of the DC bus voltage is inhibited. According to the method and the device, the regulation quantity of the IVSC loop and the regulation quantity of the OVC loop are superposed to carry out cooperative control, so that the effective suppression of the frequency doubling fluctuation of the DC bus voltage and the automatic equalization of the power of each module are accurately realized on the premise of not increasing the hardware complexity.

The invention discloses an energy storage converter predictive current control method based on data driving model self-learning, and belongs to the technical field of power electronic converter control. The energy storage converter is a half-bridge bidirectional DC-DC converter, and the method comprises the following steps: collecting the state quantity of the energy storage converter through a sensor in each control period, forming a data driving prediction model constructed by an input vector input neural network online parameter identification module, and outputting an initial duty ratio prediction value; constructing a value function, performing online optimization on an initial value through a gradient descent method to obtain a final optimal duty ratio, and simplifying a scene to directly use the initial value; comparing the optimal duty ratio with a carrier wave to generate a PWM (Pulse Width Modulation) signal to drive a power switch tube; actual inductive current is collected, an ideal duty ratio enabling the value function to be minimum is reversely solved to serve as a supervision signal, and the model weight is trained and updated online through a sample. The technical problem that traditional continuous set model predictive control depends on an accurate mathematical model is solved.

The invention relates to the technical field of intelligent control of power electronic converters and induction heating, in particular to an intelligent control system of a medium-frequency power supply, which comprises a data acquisition module configured to acquire end-side voltage data and end-side current data of power conversion hardware in real time; the feature extraction module is configured to receive the end-side voltage data and the end-side current data and extract broadband waveform distortion features; the state evaluation module is configured to receive the broadband waveform distortion characteristics and calculate a model trust entropy value based on the broadband waveform distortion characteristics; the self-adaptive control module is configured to receive the model trust entropy value, trigger a second control mode to generate a second switch instruction and send the second switch instruction to the power conversion hardware; the model trust entropy represents a prediction deviation degree of a preset robust control model to the current real physical state of the power conversion hardware; according to the invention, the problem of insufficient perception of fine-grained service parameters in the background technology is solved.

Examples described herein provide a circuit that includes a power electronics converter disposed in a vehicle, the power electronics converter to receive alternating current (AC) electrical power from an AC grid source and to provide AC electrical power to an AC load external to the vehicle. The power electronics converter includes an AC-AC converter that includes a rectifier and an inverter, the rectifier being electrically connected to the inverter by a direct current (DC) link. The circuit further includes an on-board charging module electrically connected to the power electronics converter and a battery disposed in the vehicle. The power electronics converter provides vehicle-to-load functionality by providing, to the AC load, AC electric power as an output of at least one of a 120 Vac output or a 240 Vac output.

The invention relates to the technical field of power electronic converter control, in particular to an LLC converter dynamic response capability optimization control method based on a neural network, and the method comprises the steps: building an LLC converter dynamic response mathematical model based on a frequency conversion modulation strategy; optimizing the dynamic response process of the LLC converter during load switching by selecting a differential evolution algorithm and combining the mathematical model, and collecting k groups of frequency data with optimal LLC dynamic performance during load switching; training a pre-constructed neural network model by taking the collected k groups of frequency data with optimal LLC dynamic performance for load switching as training data; and applying the trained neural network model to an LLC converter controller to realize optimization of a dynamic response process. According to the invention, the LLC converter has better dynamic response capability in the load switching process, so that the LLC converter can stably and quickly reach a new steady state.

The invention relates to the technical field of power electronics, discloses a management method of an intelligent power electronic converter, and aims to solve the problem that in the prior art, operation performance and long-term reliability cannot be collaboratively optimized. According to the method, voltage, current, temperature and vibration data are collected in real time through a multi-mode sensor, and a high-fidelity digital twinborn model fusing electromagnetism, thermodynamics and component aging mechanisms is constructed and calibrated online; based on the model, a multi-objective optimization function including efficiency, electric energy quality, residual life and accumulated damage is established in a prediction time domain, a Pareto optimal control parameter set is solved by adopting a multi-objective evolutionary algorithm, and an optimal solution is selected according to a dynamic utility function to generate a driving instruction. The system comprises a state sensing module, a digital twin modeling module, a prediction optimization module, a strategy decision module and a driving execution module, full-dimension self-adaptive closed-loop management of performance and service life is achieved, and the intelligent level, economical efficiency and reliability of the converter are remarkably improved.

The invention relates to the technical field of power electronic converters, in particular to a converter networking control method with a low-frequency impedance remodeling function. Comprising a network construction control module, a virtual impedance control module, a first coordinate transformation module, a second coordinate transformation module, a third coordinate transformation module, a current control module, a voltage filtering module, a low-frequency impedance remodeling module and a coordinate inverse transformation module. According to the method, low-frequency-band positive impedance is achieved, the stability of the power electronic converter in a weak power grid environment is improved, meanwhile, the modular design is easily integrated into an existing converter system, the oscillation risk caused by fundamental frequency negative impedance is thoroughly eliminated, broadband compatibility is achieved, the 0-200 Hz harmonic range is covered, and the performance is optimized through an adjustable remolding coefficient kz.

The invention discloses a self-adaptive control method, system and device for inertia coefficients of a network-forming converter and a storage medium, and relates to the technical field of power electronic converter control, and the method comprises the steps: collecting the DC side voltage of a converter in real time through a voltage sensor, and calculating the deviation between the DC side voltage and a DC voltage reference value; the output angular velocity deviation of the converter is obtained, the inertia coefficient of the converter is dynamically adjusted through a nonlinear function in combination with the direct-current side voltage deviation, and self-adaptive adjustment of control parameters of the converter is achieved; the dynamically adjusted inertia coefficient of the converter is substituted into a converter control link in real time, and the output characteristic of the converter is changed, so that the output performance of the converter is optimized; self-synchronization grid connection can be realized, the anti-interference capability of the system is enhanced, the converter adapts to complex working conditions, virtual inertia is provided for a power grid, the frequency of the power grid is stabilized, and the operation stability of the grid-forming converter and the new energy accepting capability of the power grid are improved.

The invention relates to the technical field of power electronic converter grid-connected control. The invention discloses a model prediction transient stability control method of a VSC-PLL system in a weak network environment. The model prediction transient stability control method is characterized by comprising the following steps: 1) constructing a dynamic model of the system: (1) constructing a physical model and a state equation; (2) discretizing the model; the core composition of the MPC optimization problem comprises (1) prediction model and time domain setting, (2) objective function design, (3) constraint condition set, and (3) rolling optimization and self-adaptive control mechanism: (1) real-time parameter updating, and (2) optimization solution and control execution. The method can realize on-line optimization of active / reactive current set values.

The present application relates to the technical field of power electronic converter, and discloses a grid-connected inverter multi-parameter online setting method, system, device and medium.The method comprises the following steps: establishing a circuit simulation model of the grid-connected inverter; obtaining the output current of the grid-connected inverter under different grid impedance conditions through the circuit simulation model, and obtaining the target control parameters of the grid-connected inverter under different grid impedance conditions through iterative search of the particle swarm optimization algorithm of the circuit simulation model; performing offline training on the parameter reasoning model through the output current of the grid-connected inverter under different grid impedance conditions and the target control parameters under the corresponding grid impedance conditions; obtaining the output current of the grid-connected inverter in real time, inputting the real-time output current into the trained parameter reasoning model, and obtaining the corresponding target control parameters; and performing online setting on the control parameters of the grid-connected inverter through the target control parameters output by the parameter reasoning model, so that fast setting can be realized.

The invention relates to the technical field of power electronic conversion, in particular to a seamless switching control method and system for grid-connected and off-grid modes of an energy storage converter, and the method comprises the following steps: mode pre-judgment, seamless switching, virtual inertia and damping simulation and re-grid-connected pre-synchronization. The system comprises a multi-mode detection and pre-judgment module, a unified multi-mode controller, a state synchronization and observer module and a phase-locked loop-free synchronizer. According to the method, the whole process control problem from grid connection to grid disconnection and then grid connection is solved, the seamless degree of switching reaches a new level, and the active supporting capacity and friendly grid connection performance of the energy storage converter serving as a micro-grid core control unit are comprehensively improved; and the method has an important value for promoting the construction and development of a high-reliability micro-grid.

The invention discloses an operation parameter optimization method and system for improving the overload capacity of a power electronic converter, and belongs to the technical field of power electronics. The method comprises the following steps: constructing an output current model considering current ripples in a switching period, and obtaining an accurate current waveform expression; calculating conduction loss and switching loss of each power device in each switching period based on the model; under a set temperature rise or loss constraint condition, parameters such as direct-current voltage and switching frequency are optimized through an optimization algorithm, and the optimized parameters are applied to converter operation. The method solves the problem that loss estimation is inaccurate due to the fact that a traditional simplified model ignores current ripples, through precise modeling, refined loss calculation and scientific parameter optimization, the thermal stress of a device is remarkably reduced, the overload capacity of the converter is improved, the method is suitable for various topologies such as a two-level converter, a three-level converter and a direct-current converter, and the method has wide application prospects. The method can be widely applied to the fields of new energy and rail transit.

The invention relates to the technical field of power systems, in particular to a frequency-locked loop control method and system based on a double-second-order generalized integrator. According to the method, a traditional phase-locked loop is replaced by a frequency-locked loop to provide center frequency for the bisecond-order generalized integrator, and high-precision and high-response-speed real-time tracking of power grid frequency is achieved. And based on a DSOGI-FLL structure, parallel processing is carried out on the axis signal and the axis signal after Clark transformation, an orthogonal signal is generated, a positive sequence component and a negative sequence component are decoupled, and frequency doubling fluctuation under the asymmetric working condition of the power grid is eliminated. A phase angle of a positive sequence component is locked by combining a single synchronous coordinate system phase-locked loop, a positive sequence dq-axis component and a negative sequence dq-axis component are output through dq conversion, and a power grid synchronizing signal is rapidly obtained when voltage drops, frequency abrupt changes and three-phase faults occur. According to the method, the dynamic response speed and the detection precision can be remarkably improved, additional parameter compensation calculation is avoided, the universality of the method is enhanced, and a high-reliability synchronization reference is provided for fault ride-through of the power electronic converter.

The invention provides a dual-mode parallel competition-dominated self-synchronizing voltage source wind turbine generator set and a control method thereof, and the wind turbine generator set comprises a wind power generation device which is composed of a wind turbine and a generator and is used for converting wind energy into electric energy; the alternating current / direct current conversion module consists of a power electronic converter and a chopper circuit and is used for realizing conversion between alternating current electric energy and direct current electric energy and realizing unloading when transient direct current voltage exceeds the limit; the self-synchronizing voltage source generation control module is composed of a dual-mode parallel competitive dominant control module, a modulation voltage control module and a synchronous phase angle control module and is used for autonomously establishing voltage, autonomously synchronizing a power grid and supporting transient frequency and voltage of the power grid; according to the direct current bus voltage and the power grid voltage, the self-synchronizing voltage source characteristics of the unit under multiple operation working conditions such as wind speed disturbance and power grid faults are maintained through state keeping and competitive leading of the two voltage source control modes. The invention is suitable for doubly-fed and full-power wind turbine generators, and comprises control, equipment and a system.

The invention provides an active support self-adaptive control method for a network construction type converter. The active support self-adaptive control method for the network construction type converter comprises the following steps: S01, calculating a frequency difference value and a frequency change rate value of the network construction type converter; s02, calculating an inertia coefficient according to a frequency change degree comprehensive threshold value; s03, calculating a damping coefficient according to the frequency difference threshold value; s04, realizing active support control by simulating the characteristics of a synchronous machine; and S05, performing pulse width modulation on the internal potential through vector control. According to the active support self-adaptive control method for the network construction type converter, main parameters are self-adaptively adjusted according to the external environment of the system to suppress power and frequency fluctuation, the method can be suitable for the operation occasion of a power electronic converter, and particularly, the steady state of the network construction type converter is not influenced by external disturbance; therefore, the active support control performance of the converter is improved.

The invention discloses an inertia support control method and device for a power electronic converter, electronic equipment and a storage medium, and belongs to the field of power electronic converters, and the method comprises the steps: obtaining the power grid frequency of a common coupling point of the power electronic converter in real time; when each power grid frequency is obtained, calculating a frequency deviation and a frequency change rate between the power grid frequency and a preset power grid rated frequency; when the frequency deviation and the frequency change rate both exceed corresponding preset response threshold values, a direct-current voltage reference value is calculated and generated according to the current frequency deviation and the current frequency change rate; and a control instruction is sent to a control terminal, so that after the control instruction is received, the direct-current side voltage of the power electronic converter is adjusted to the direct-current voltage reference value, and then energy stored in a direct-current side capacitor in the power electronic converter is released. Therefore, by implementing the method, the problem of inertia support response lag in the prior art can be solved.

The invention discloses a multi-turn-ratio degree-of-freedom magnetic coupling direct-current boost converter, and belongs to the field of power The problems that when an existing traditional Boost converter achieves high voltage gain, the boosting capacity is limited, and the voltage stress of a switching device is large are solved. Compared with the prior art, the multi-winding coupling inductors (N1, N2 and N3) are arranged, the extra design freedom degree is provided by setting different turn ratios, the voltage gain does not only depend on the duty ratio any more, the high voltage gain can be obtained under the medium duty ratio, meanwhile, the voltage stress of the power switch tube is remarkably reduced, and the efficiency and reliability of the converter are improved. The boost converter is mainly used for boost conversion.

The invention relates to the field of power electronic converters and control, in particular to an SOP power module dead-zone effect suppression method, which comprises the following steps: acquiring the current transmission power of an SOP power module; based on the transmission power, generating a first bus voltage instruction used for controlling an AC-DC side direct current bus voltage and a second bus voltage instruction used for controlling a DC-AC side direct current bus voltage, adjusting the corresponding direct current bus voltage so as to inhibit polarity reversal of a DAB converter bridge port voltage, and according to the transmission power of the SOP power module, adjusting the polarity of the DAB converter bridge port voltage. A first bus voltage instruction and a second bus voltage instruction are generated, the first bus voltage instruction and the second bus voltage instruction are made to be unequal during light load, a bus voltage difference value is formed, and it is ensured that the direct-current bus voltages on the two sides meet the condition for restraining DAB bridge port voltage polarity reversal in the dead-zone time period by means of compensation for frequency doubling fluctuation components in the direct-current bus voltages. Current zero step is eliminated, soft switching is recovered, voltage stability under light load is improved, extra hardware or complex control is not needed, and engineering realization is simple and convenient.

The invention discloses a hardware-in-loop simulation method based on a high-order generalized average model and a related device, and belongs to the technical field of power electronic converter simulation. The method comprises the following steps: listing a piecewise linear state equation of a target power electronic converter; performing moving Fourier expansion on the piecewise linear state equation to obtain a high-order generalized average model of the power electronic converter; calculating moving Fourier coefficients of a switching signal and an input signal of the power electronic converter, and substituting the moving Fourier coefficients into a high-order generalized average model of the power electronic converter to obtain a differential equation of each order of moving Fourier coefficient about a circuit variable; and solving the differential equation, calculating to obtain a mobile Fourier coefficient of each variable in the circuit, and further reconstructing a time domain waveform of each circuit variable at the center moment to realize simulation of the target power electronic converter. According to the method, the simulation step length of the model is greatly increased, and computing resources are saved; meanwhile, the precision requirement is met, and the steady-state and transient-state behaviors of the circuit can be accurately predicted.

The application discloses a kind of three-phase rectifier multiple switch tube open-circuit fault diagnosis methods based on voltage deviation, belong to power electronic converter fault diagnosis technical field.Method includes: obtaining relevant signal for diagnosis;According to three-phase voltage, three-phase current, three-phase inductance value, three-phase equivalent resistance value and switching period, the actual value of three-phase line voltage is calculated;According to DC voltage and the duty cycle of switch tube on three-phase bridge arm, the expected value of three-phase line voltage is calculated;Difference is obtained between the expected value and actual value of three-phase line voltage;The deviation value of three-phase line voltage is compared with first preset threshold and second preset threshold, to determine the polarity of the deviation value of three-phase line voltage;Wherein, first preset threshold is less than second preset threshold;The polarity of the deviation value of three-phase line voltage is combined with voltage phase, to determine fault switch tube.The application can quickly diagnose for various situations of multiple switch tube fault, including single switch fault, two switch tubes in succession fault, two switch tubes simultaneous fault.

The present application relates to a kind of full digital hysteresis control method of inductance-free three-level inverter sampling time online prediction, belong to power electronic converter technical field, solve the dependence of full digital hysteresis control algorithm of three-level converter on high sampling rate, and the problem of being greatly influenced by main circuit filter parameter, it includes determining the mathematical model and modulation method of three-level converter, determining the full digital three-level hysteresis control algorithm of inductance-free sampling time online prediction, correction prediction sampling time interval.The full digital hysteresis control method is used for inductance-free three-level inverter hysteresis control simulation.

The invention relates to the field of pulse width modulation of power electronic converters, in particular to a pulse width modulation method and system for minimizing switching loss, which are suitable for minimizing switching loss under any modulation ratio and power factor of a three-level neutral-point clamped inverter topology. The three-level space vector diagram is divided into 6 large sectors and corresponding 24 areas according to a nearest three-vector synthesis principle. All possible five-segment switch sequences in different clamping phases of each region are obtained according to a nearest three-vector synthesis principle, the obtained five-segment switch sequences are selected according to a certain rule and checked according to a corresponding rule, and zero-sequence component calculation is performed on the five-segment switch sequences in different clamping phases. And finally, selecting a zero-sequence component under the corresponding clamping phase according to the current maximum phase or secondary maximum phase. And meanwhile, modeling is carried out on the switching loss of the switching loss minimization DPWM modulation and the switching loss of the traditional DPWM1 modulation, and the effectiveness of the pulse width modulation method is verified through comparison.

The invention discloses a high-gain multi-inductor direct-current boost converter, and belongs to the field of power electronic converters. The technical problems that in the prior art, a direct current boost converter is limited in boost capacity, large in conduction loss, low in efficiency and complex in system are solved. Through multi-inductor staged energy storage and energy release and in combination with charging and discharging of the capacitors, multiple superposition of input voltage and inductive induction voltage is realized, so that extremely high voltage gain is obtained under the condition of small duty ratio. Meanwhile, voltage stress is dispersed to a plurality of inductors and diodes, so that the stress of a single device is effectively reduced, the conduction loss is reduced, and the reliability and efficiency of the system are improved. The boost converter is mainly used for boost conversion.

This invention discloses a data-driven intelligent operation and maintenance method for vehicle-to-grid (V2G-Vehicle-Storage) systems. The method collects real-time operating status data of heterogeneous power electronic converters and performs data preprocessing. Based on the preprocessed data, standardized input is generated and fed into a pre-built and trained fault identification model based on a convolutional neural network, outputting fault type identification results. Based on the fault type identification results, fault classification, fault item confirmation, fault cause analysis, and automatic generation of fault handling solutions are performed. This invention's technical solution optimizes the problems of lagging operation and maintenance diagnosis and high false alarm rates under current conditions through deep learning algorithms, realizing a data-driven end-to-end process of system fault diagnosis, location, analysis, and operation and maintenance, ensuring the safe operation of the system.

The invention discloses a transformer capable of suppressing common-mode interference and a booster circuit, and belongs to the technical field of power electronic converters, the transformer comprises a magnetic core, a primary winding and a secondary winding, the primary winding and the secondary winding are formed by winding multiple layers of coaxial cables, shielding conductors of the primary winding and the secondary winding are configured to have the same number of winding turns and winding direction, the structure of the transformer is applied to a staggered winding mode and is connected to a static potential point, so that the potential distribution between the transformer and the static potential point is consistent, the voltage difference on a distributed capacitor is close to zero, common-mode conducted interference is fundamentally inhibited, the transformer structure is also applicable to the staggered winding mode, and the process can be simplified while the leakage inductance is reduced. The booster circuit using the transformer realizes efficient and low-interference multipath isolation output.

This invention proposes a quadratic dual-coupled inductor DC-DC converter, belonging to the technical field of power electronic converters. Based on a quadratic cascaded boost converter, the quadratic dual-coupled inductor DC-DC converter splits the input current into two branches on the input side, and both switching transistors are simultaneously turned on and off. Two sets of coupled inductors are introduced on the input side, and several capacitors and diodes are added on the output side to form a CLC coupled inductor voltage multiplier unit. This invention has high voltage gain and is suitable for new energy power generation systems such as fuel cells and photovoltaic cells.

The invention provides a dual-mode parallel competition-dominated self-synchronizing voltage source type photovoltaic power generation unit, and the power generation unit comprises a photovoltaic array which is composed of photovoltaic modules and is used for converting illumination into electric energy; the direct current / alternating current converter consists of a power electronic converter and is used for converting the direct current generated by the front-end photovoltaic array into alternating current; the self-synchronizing voltage source generation control module is composed of a dual-mode parallel competitive dominant control module, a modulation voltage control module and a synchronous phase angle control module and is used for autonomously establishing voltage, autonomously synchronizing a power grid and supporting transient frequency and voltage of the power grid; and according to DC bus voltage fluctuation characteristics and power flow characteristics, through state maintenance and competitive leading of two voltage source control modes, self-synchronizing voltage source characteristics of the photovoltaic power generation unit under multiple operation conditions such as illumination abrupt change and power grid faults are maintained, and DC bus voltage stabilization without a DC crowbar is realized. The invention is applicable to string type and centralized photovoltaic, including control, equipment and systems.

The invention discloses a reactive power optimization control method suitable for a series resonance dual active bridge, relates to the technical field of power electronic converter control, and solves the problem that an effective compensation scheme is not provided for an incomplete soft switching problem caused by dead time in the prior art. And the requirement of all-working-condition efficient operation in engineering application is difficult to meet. Based on triple phase shift control, the optimal phase shift angle combination is accurately solved through the power factor Lagrange function and the KKT condition, the reactive power of the primary side or the secondary side can be counteracted in a targeted manner, and the energy circulation of the resonant cavity is effectively inhibited; meanwhile, soft switching boundary analysis and critical phase compensation are combined, so that zero-voltage switching of all main switching tubes in a full-voltage gain and full-load range can be ensured, and switching loss is reduced; and a mode switching mechanism is designed in control logic to adapt to dynamic working condition response requirements, so that the energy transmission efficiency and working condition adaptability of the series resonance dual-active bridge converter are greatly improved.