An online UPS with improved input-output characteristics

Joós, G.; Lin, Yu‐Ju; Ziogas, P.D.; Lindsay, I.F.

doi:10.1109/apec.1992.228356

Cited by 16 publications

(2 citation statements)

References 6 publications

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“…A line-interactive UPS topology based on a series-parallel compensated system is also termed as the ''delta-conversion'' UPS system. It improves performance and has several advantages compared to the conventional UPS systems [26]- [32]. Moreover, it comprises of two converters, one is in parallel to the load, the other one is tied in series with the utility through a series transformer, as depicted in Fig.…”

Section: Introductionmentioning

confidence: 99%

A Single-Phase Line-Interactive UPS System for Transformer-Coupled Loading Conditions

Bukhari

2020

IEEE Access

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A line-interactive uninterruptible power supply (UPS) system is one of the important installations implemented by industrial users to provide continuous power to sensitive industrial applications. Such loads often come with isolation transformers for voltage matching and protection purposes. Hence, a line-interactive UPS system experiences a serious problem of transient current when it operates under transformer-coupled loading conditions. The occurrence of this transient current can either impair the apparatus itself or turn on the overcurrent safety devices. In any situation, the interruption of electrical power for sensitive industrial loads is unavoidable. So as to keep the uninterrupted power and to eliminate transient current for industrial applications operating under transformer-coupled loading conditions, we propose a single-phase line-interactive UPS system based on a customary current-regulated inverter. The inverter of the proposed UPS system employs an improved current-regulating scheme implemented in a stationary frame of reference which regulates the load current and never let it to increase than a prescribed value as the transformer-coupled loads are turned on. Laboratory test results obtained under various operating and loading conditions of the single-phase line-interactive UPS system verify the operation of the proposed system. INDEX TERMS Line-interactive, flexible loading conditions, transient current, transformer-coupled loads.

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Section: Introductionmentioning

confidence: 99%

A Single-Phase Line-Interactive UPS System for Transformer-Coupled Loading Conditions

Bukhari

2020

IEEE Access

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“…A UPS is required to deliver a well-regulated sinusoidal output voltage with low THD to the load, regardless of whether the utility AC power source is normal or not. Online and offline UPS systems are the two major UPS schemes [1][2][3][4][5][6]. Online UPS systems are generally preferred because of high reliability and good voltage regulation.…”

Section: Introductionmentioning

confidence: 99%

Improved DSP-controlled online UPS system with high real output power

Liang

Shyu

2004

IEE Proc., Electr. Power Appl.

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A circuit topology is proposed for single-phase online UPS systems. The proposed circuit incorporates a built-in bidirectional AC/DC converter, which provides power factor correction and active power filtering. The input stage, based on a bidirectional AC/DC converter, functions as a rectifier with unity power factor correction for normal AC line mode operation, and as an active power filter for outage mode operation. During input power failure, the bidirectional AC/DC converter functions as an active power filter, providing reactive power to the load. Simultaneously, the DC/AC voltage inverter output stage supplies real power from the battery bank to the critical load. The real power capability is improved compared with that of a conventional online UPS system, and extra loads can be connected to the UPS system during outage. The power circuit of the proposed UPS system is presented and analysed. Circuit models are derived and a UPS digital control system using a digital signal processor (DSP) is developed. Finally, simulated and experimental results obtained from a laboratory prototype are presented to confirm the feasibility and features of the proposed UPS scheme.

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Performance analysis of parallel-processing UPS systems

Lin

Joós

Lindsay

Proceedings Eighth Annual Applied Power Electronics Conference and Exposition,

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An online UPS with improved input-output characteristics

Cited by 16 publications

References 6 publications

A Single-Phase Line-Interactive UPS System for Transformer-Coupled Loading Conditions

A Single-Phase Line-Interactive UPS System for Transformer-Coupled Loading Conditions

Improved DSP-controlled online UPS system with high real output power

Performance analysis of parallel-processing UPS systems

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