|SNO||High-Power-Factor Rectifier Using the Modified SEPIC Converter Operating in DiscontinuousConduction Mode||The theoretical and experimental analysis of a modified version of the SEPIC dc–dc converter used as pre regulatorOperating in discontinuous conduction mode (DCM) is presented in this paper. The proposed converter presents a low input current ripple operating in DCM, and the switch voltage is lower than the output voltage. The switch voltage reduction increases the converter reliability and a low drain-to-source on-resistance (RDSon ) MOSFET can be used depending on the converter specification. Moreover, a digital control technique is applied to theproposed converter in order to reduce the third-harmonic input current distortion resultant of the operation in DCM. Finally, a
100-W prototype was developed operating with efficiency equal to 95.6%.
|PER-1||Infinity-Norm of Impedance-Based Stability Criterion for Three-Phase AC Distributed Power Systems With Constant Power Loads||This paper presents a stability criterion for three phase AC distributed power system (DPS). While the source outputimpedance and the load input admittance under synchronous reference frame are generally investigated to predict the stability of the three-phase AC DPS, the infinity-norms of the impedance and admittance are innovatively adopted in the proposed criterion to improve the computational complexity and the conservatism. Meanwhile, the computational complexity and the conservatism of the proposed criterion are analyzed and compared with existing ones. Furthermore, the terminal characteristics of the studied three-phase AC DPS composed of an LC filter and a three-phaseboost rectifier, which cover the source output impedance and the load input admittance, are comprehensively modeled. Finally, the effectiveness of the proposed criterion is validated by experimental results.||2015|
|PER-2||Improved Selective Harmonics Elimination Scheme With Online Harmonic Compensationfor High-Power PWM Converters||To reduce the low-order harmonics produced by the high-power pulse width-modulated (PWM) converters, selectiveHarmonic elimination (SHE) scheme is commonly used due to its superior harmonic performance at low switching frequency. However, as an off-line modulation technique, the SHE scheme itself lacks the capability to realize the active compensation of the grid background harmonics. To enable the active compensation ability of the SHE-modulated PWM converters, this paper proposes an active compensation method through the jittering of SHE phase angle. The proposed method can realize the real-time compensation of the preexisting system background harmonics in high-power PWM converters’ system. An application example on a high-power PWM current-source rectifier (CSR) system is provided in this paper. Experimental results show that the proposed method can effectively attenuate the line current harmonics caused by the grid background harmonics in the high-power PWM CSR systems.||2015|
|PER-3||Direct Power Control Based on Natural Switching Surface for Three-PhasePWM Rectifiers||In this letter, the natural trajectories of the output voltage and the inductor currents for three-phase pulse width modulation rectifiers are presented. On this basis, a novel direct power control (DPC) using the natural switching surface is proposed by combining DPC with the boundary control. Compared to the conventional DPC, the proposed control considers the output voltage when selecting the switching states. Therefore, the proposed control does not need an outer voltage control loop and can highly improve the dynamic performance of the dc output voltage. TheExperimental results on a 1.5-kW prototype confirm the correctness of the theoretical analysis. They verify the feasibility and the validity of the proposed control and show the excellent dynamic performance.||2015|
|PER-4||A Family of Soft-Switching DC–DC Converters Based on a Phase-Shift-Controlled Active Boost Rectifier||High efficiency and high power density can be achieved with a dc–dc transformer by operating all the switchesat a fixed 50% duty cycle. However, the output voltage of the dc–dc transformer cannot be regulated. Novel rectifiers named active boost rectifiers (ABRs) are proposed in this paper. Basically, an ABR is composed of a traditional diode rectifier and a bidirectional switch. By adopting phase-shift control between the primary- and secondary-side switches, the output voltage regulation can be achieved when introducing the ABR to a dc–dc transformer. As a result, a family of novel soft-switching dc–dc converters is harvested. When the proposed converter operates in the soft-switching continuous conduction mode, zero-voltage switching (ZVS) performance for all the primary- and secondary side switches is achieved. When the converter operates in the iscontinuous conduction mode, zero current switching (ZCS) for the primary-side switches and ZVS for the secondary-side switches are achieved. Furthermore, the diode reverse-recovery problem is alleviated by employing the ABR and phase-shift control scheme. As an example, the full-bridge converter with voltage-doublers ABR is analyzed to verify the proposed ABR concept and converters. The operation principles, voltage conversion ratio, and output characteristics are analyzed in depth. Finally, experimental results are provided to verify the feasibility and effectiveness.||2015|