Wide Voltage Output Research Articles

A Hybrid Extended Phase Shift Modulation Strategy for DAB Converter With DC Blocking Capacitor to Extend ZVS Range and Reduce RMS Current

This article is aimed at enlarging the zero-voltage switching (ZVS) range and reducing current stress for the dual-active-bridge (DAB) converter with dc blocking capacitors (DCBCs). A hybrid extended phase shift modulation strategy (HEPSMS) is proposed, which makes the converter switch between the full-bridge mode and the half-bridge mode to obtain multivoltage matching operation points. Thus, the root mean square (rms) current and the burden of achieving full load range ZVS are reduced. In addition, the voltage–second of the leakage inductor is controlled to achieve equivalent voltage matching under wide voltage output, thereby simplifying the control law and achieving full load range ZVS under a wide voltage range. The operation principle, ZVS range, and rms current are analyzed and compared with the conventional modulation method. Finally, a 1-kW experimental prototype with a 200-V input and a 100–400-V output was built to verify the feasibility and effectiveness of the proposed method.

Design and Implementation of Adjustable Voltage Source Module for Ion Chromatography

Abstract Undeniably, adjustable power supply has many applications in ion chromatography. One example would be that a safe and stable adjustable power supply is indispensable for the driving part of the suppressor in ion chromatography. However, the traditional design of adjustable power supply suffers from high complexity, leading to its incompetence for practical engineering under the background of the continuous shortage of chips. Therefore, a method for an adjustable power supply module for ion chromatography is proposed and studied. Firstly, the microprocessor is used to output the MCPWM wave to control the output voltage of the flyback transformer. Secondly, the OCADC is used to collect the feedback voltage. Thirdly, the duty cycle of the MCPWM is adjusted using the PID algorithm to achieve constant voltage output. Further, hardware overcurrent protection is realized through MCPWM fast interrupt function. By this method, an adjustable power supply with a wide voltage output range, high current, and low voltage ripple can be output with less chip resources. Both the theoretical design scheme and the specific hardware circuit of this design is presented. Moreover, a simulation verification analysis is made. Finally comes the verification of the feasibility of this method.

Analysis and Implementation of a Frequency Control DC–DC Converter for Light Electric Vehicle Applications

In order to realize emission-free solutions and clean transportation alternatives, this paper presents a new DC converter with pulse frequency control for a battery charger in electric vehicles (EVs) or light electric vehicles (LEVs). The circuit configuration includes a resonant tank on the high-voltage side and two variable winding sets on the output side to achieve wide output voltage operation for a universal LEV battery charger. The input terminal of the presented converter is a from DC microgrid with voltage levels of 380, 760, or 1500 V for house, industry plant, or DC transportation vehicle demands, respectively. To reduce voltage stresses on active devices, a cascade circuit structure with less voltage rating on power semiconductors is used on the primary side. Two resonant capacitors were selected on the resonant tank, not only to achieve the two input voltage balance problem but also to realize the resonant operation to control load voltage. By using the variable switching frequency approach to regulate load voltage, active switches are turned on with soft switching operation to improve converter efficiency. In order to achieve wide output voltage capability for universal battery charger demands such as scooters, electric motorbikes, Li-ion e-trikes, golf carts, luxury golf cars, and quad applications, two variable winding sets were selected to have a wide voltage output (50~160 V). Finally, experiments with a 1 kW rated prototype were demonstrated to validate the performance and benefits of presented converter.

Fractional Controller Design of a DC-DC Converter for PEMFC

Proton Exchange Membrane Fuel Cell (PEMFC) is difficult for application because of its high current and wide voltage output. A fractional order PID controller is introduced to a Four-Switch Buck-Boost DC/DC converter to stabilize the power output in this paper. To reduce the inductor current ripple, a kind of dual-triggered switch strategy is employed in detail, and an accurate dynamic model of DC/DC converter is proposed for fuel cell measurement and control system. Then a fractional order PID controller is designed for voltage module compensation, in which a stochastic inertia weight PSO algorithm is employed to optimize the parameters of this controller. The results of simulation and experiment indicate that the compensation effect of fractional order PID controller has better performance than the integer order controller, which is robust to the variation of fuel cell system dynamics and power request.