Research on the Intelligent Control Strategy of the Fuel Cell Phase-Shifting Full-Bridge Power Electronics DC-DC Converter

focus of all countries.As an effective new energy,the fuel cell has attracted the attention of scholars.However,due to the particularity of proton exchange membrane fuel cell(PEMFC),the performance of traditional PI controlled phase-shifted full-bridge power electronics DC-DC converter cannot meet the needs of practical application.In order to further improve the dynamic performance of the converter,this paper first introduces several main topologies of the current mainstream front-end DC-DC converter,and analyzes their performance in the fuel cell system.Then,the operation process of the phase-shifted fullbridge power electronics DC-DC converter is introduced,and the shortcomings of the traditional PI control are analyzed.Finally,a double closed-loop adaptive fuzzy PI controller is proposed,which is characterized by dynamically adjusting PI parameters according to different working states to complete the intelligent control of phase-shifted full-bridge DC-DC converter.The simulation results in MATLAB/Simulink show that the proposed algorithm has good a control effect.Compared with the traditional algorithm,the overshoot and stabilization time of the system are shorter.The algorithm can effectively suppress the fluctuation of the output current of the fuel cell converter,and is a very practical control method.

Research on Phase-Shifted Full-Bridge Circuit Based on Frequency and Phase-Shift Synthesis Modulation Strategy

The full-bridge converters usually use transformer leakage inductance and parallel resonant capacitors to achieve smooth current commutation and soft switching functions,which can easily cause problems such as energy leakage and significant duty cycle loss.This paper designs a novel full-bridge zero-current(FB-ZCS)converter with series resonant capacitors and proposes a frequency and phase-shift synthesis modulation(FPSSM)control strategy based on this topology.Compared with the traditional parallel resonant capacitor circuit,the passive components used are significantly reduced,the structure is simple,and there is only a slight energy loss.By controlling the charging time of the capacitor,it can be achieved without additional switches or auxiliary circuits.The automatic control of capacitor energy based on input current addresses the low efficiency of the traditional control strategies.This paper introduces its principle in detail and verifies it through simulation.Finally,an experimental prototype was built further to demonstrate the feasibility of the theory through experiments.The module can be applied to a photovoltaic DC collection system using input parallel output series(IPOS)cascade to provide a new topology for large-scale,long-distance DC transmission.

One step to generate quantum controlled phase-shift gate using a trapped ion

This paper presents a very simple scheme for generating quantum controlled phase-shift gate with only one step by using the two vibrational modes of a trapped ion as the two qubits. The scheme couples two vibration degrees of freedom coupled with a suitable chosen laser excitation via the ionic states.

Study of the EAST Fast Control Power Supply Based on Carrier Phase-Shift PWM

EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.

Digital control system for pulsed MIG welding power based on STM32

Digital control system for pulsed MIG welding power based on STM32 is set up with 32-bit STM32FlO3ZET6 directing against the pulse waveform modulation of pulsed MIG welding. High-frequency inverter and medium-low frequency pulse waveform modulation of pulsed MIG welding are realized by using the integrated PWM module within STM32 to generate PWM signals of phase-shifted full-bridge soft-switching and constant-current control of output current is achieved by means of anti-windup PI control algorithm to improve the stability and reliability of control system. Experimental results demonstrate that the designed digital control system based on STM32 can achieve pegrect pulsed MIG welding technique with stable welding process and good weld appearance, fully demonstrating the advantages of digital control based on STM32.

Non-isolated stacked bidirectional soft-switching DC-DC converter with PWM plus phase-shift control scheme

In this paper, a non-isolated stacked bidirectional DC-DC converter with zero-voltage-switching(ZVS) is introduced for the high step-up/step-down conversion systems. The extremely narrow turn-on and/or turn-off duty cycle existing in the conventional bidirectional buck-boost converters can be extended due to the stacked module configuration for large voltage conversion ratio applications. Furthermore, the switch voltage stress is halved because of the series connection of half bridge modules. The PWM plus phase-shift control strategy is employed, where the duty cycle is adopted to regulate the voltages between the input and output sides and the phaseshift angle is applied to achieve the power flow regulation.This decoupled control scheme can not only realize seamless bidirectional transition operation, but also achieve adaptive voltage balance for the power switches. In addition, ZVS soft-switching operation for all active switches is realized to minimize the switching losses. Finally, a prototype of 1 kW operating at 100 kHz is built and tested to demonstrate the effectiveness of the proposed converter and the control strategy.

Widen the Zero-Voltage-Switching Range and Secure Grid Power Quality for An EV Charger Using Variable-Switching-Frequency Single-Dual-Phase-Shift Control

Compared to conventional electrical-vehicle(EV)on-board chargers utilizing a front-end Power-Factor-Correction(PFC)+an isolated DC/DC converter,which limits the wall-to-battery efficiency to~94%,a new control strategy using variable switching frequency(VSF)and variable phase shifts frees the PFC stage thereby getting rid of the DC link capacitor and further increasing the system efficiency and power density.The challenge is to secure zero-voltage-switching(ZVS)turn-on for all switches within the full-power range.In this paper a novel VSF single-dual-phase-shift(SDPS)control strategy is proposed,which consists of three control freedoms,i.e.,two phase shifts and one variable switching frequency to secure ZVS and achieve PFC simultaneously.ZVS boundaries are pictured and compared among single-phase-shift(SPS),dual-phase-shift(DPS)and the proposed single-dual-phase-shift(SDPS)control.Simulation results and experimental validation through a level-2 EV on-board charger indicate that by using the proposed SDPS control,both ZVS and PFC are secured not only for the heavy load but also for the light load,without sacrificing the system efficiency.

A Photovoltaic Generation System Based on Wide Voltage-Gain DC-DC Converter and Differential Power Processors for DC Microgrids

In this paper,a photovoltaic(PV)generation system based on front-stage differential power processors(DPP)and BACK-stage centralized wide voltage-gain converter is proposed.The resonant switched capacitor(ReSC)converter,which features high power density and high efficiency,is employed as the differential power processor and aims at processing the differential power among series-connected PV modules,avoiding the great power loss caused by power mismatch of PV modules.The ReSC converter in PV system can operate in equalization mode or MPPT mode and both modes are researched.The BACK-stage DC-DC converter is implemented as the dual-phase-shift controlled full-bridge converter(DPS-FBC).It has high conversion efficiency and wide voltage gain,suitable for PV generation applications.The current source control for grid-connected mode and the voltage source control for islanding mode are developed for DPS-FBC.Therefore,for the whole system with front and BACK stage converters,the dual-mode control strategy is proposed.When the system is connected to the grid,DPS-FBC operates as the current source for global MPPT for PV modules while ReSC converters operate in maximum power point tracking(MPPT)mode for local MPPT.When the system operates in an island,DPS-FBC works as the voltage source for constant output voltage control and ReSC converters work in equalization mode.The mode switch is based on the voltage of output DC bus.Simulations and experiments verify the feasibility of the proposed PV generation system and the effectiveness of the proposed control algorithm.