Application of a Current and Voltage Mixed Control Mode for the New Fast Control Power Supply at EAST

A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.

On-chip frequency compensation with a dual signal path operational transconductance amplifier for a voltage mode control DC/DC converter

A novel onchip frequency compensation circuit for a voltagemode control DC/DC converter is pre sented. By employing an RC network in the two signal paths of an operational transconductance amplifier （OTA）, the proposed circuit generates two zeros to realize high closedloop stability. Meanwhile, full onchip integration is also achieved due to its simple structure. Hence, the number of offchip components and the board space is greatly reduced. The structure of the dual signal path OTA is also optimized to help get a better transition response. Im plemented in a 0.5 #m CMOS process, the voltage mode control DC/DC converter with the proposed frequency compensation circuit exhibits good stability. The test results show that both load and line regulations are less than 0.3%, and the output voltage can be recovered within 15 #s for a 400 mA load step. Moreover, the compensation components area is less than 2% of the die＇s area and the board space is also reduced by 11%. The efficiency of the whole chip can be up to 95%.

MESO-based Robustness Voltage Sliding Mode Control for AC Islanded Microgrid

A new modified extended state observer(MESO)-based robustness voltage sliding mode control(SMC)strategy is proposed for an AC islanded microgrid under system uncertainties including system parameter and load variation.First,the disturbance effect on the system is regarded as a lumped uncertainty,and a state space model of the uncertain islanded microgrid system is established.Then,a modified extended state observer is designed to estimate external disturbances and internal perturbation.Finally,considering the lumped uncertainty,a sliding mode controller with a multi-power reaching law is proposed to enable the output voltage of the system to track its reference voltage rapidly and accurately,and to enhance the robustness of the system.The simulation results confirm that the proposed robustness voltage control strategy can perform satisfactory voltage control and demonstrate a strong capability to reject parameter and load variation.

Analysis, modeling and simulation of step up converter using Matlab–Simulink and simplorer

The basic configuration of step up converter usually used in photovoltaic solar systems to increase the DC voltage generated at their outputs suffers from some drawbacks just like high ripple in the output voltage,greater losses in the system and unstable dynamic behavior.To eliminate these drawbacks,this paper introduces a two-phase connection of step up converter with uncoupled smoothing reactors.Detailed analysis,simulation and control strategy have been proposed in this paper to investigate the advantages of using such connection with uncoupled reactors.This paper is intended to prove that two-phase connection with uncoupled reactors helps increasing the output power of the converter,minimizing its output ripple and making its control easier and more efficient.It also increases the converter chopping frequency and consequently decreases the size of smoothing reactors and filters used in the system.Concerning the design of such converters,it requires a long working period of time with a significant cost and specific technical tests at nominal operating points.Therefore,simulation can essentially decrease economic and development costs.Using modulation and simulation software techniques(Simplorer,Simulink,and Matlab)throughout this paper helped simulation of very fast the converter behavior and accurate determination of its dynamic characteristics.Moreover,the paper deals with modulation of voltage control technique using Matlab and Simplorer,thus regulating the converter output current and voltage.Simulation results show that this control technique provides robust output current and voltage of step up converters and is more feasible for their chopper up conversion technique.