• Journal of Power Electronics
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• v.14 no.2
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• pp.324-340
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• 2014

Recent developments in power electronics technology have spurred interest in the use of renewable energy sources as distributed generation (DG) generators. The key component in DG generators is a grid-connected inverter that serves as an effective interface between the renewable energy source and the utility grid. The multifunctional inverter (MFI) is special type of grid-connected inverter that has elicited much attention in recent years. MFIs not only generate power for DGs but also provide increased functionality through improved power quality and voltage and reactive power support; thus, the capability of the auxiliary service for the utility grid is improved. This paper presents a comprehensive review of the various MFI system configurations for single-phase (two-wire) and three-phase (three- or four-wire) systems and control strategies for the compensation of different power quality problems. The advances in practical applications and recent research on MFIs are presented through a review of nearly 200 papers.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.133-139
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• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.97-103
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• 2018

This paper addresses an improved naval combat UPS(Uninterruptable Power Supply) system under abnormal transients. Previously, thermistor and varistor elements were used to cope with transient overvoltage and overcurrent, however the UPS was frequently unavailable because it was vulnerable to abnormal transient voltage generated during system operation. In order to overcome this problem and protect UPS system, this paper proposes an input power cut-off circuit that detects the initial input power and abnormal transient voltage generated during operation, improvement of power control sequence, and a method to prevent malfunction of an inverter and CPU. The UPS system implementing the proposed method was simulated by input power variable test using programmable AC/DC generator, and finally validated its reliability and stability through field tests by mounting on multifunctional console of naval combat system.