Three-phase Line-interactive Uninterruptible Power Supply Research Articles

A line-interactive UPS system implementation with series-parallel active power-line conditioning for three-phase, four-wire systems

This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF)-based controller is used for harmonic and reactive power compensation generated from any configuration of non-linear loads. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulsewidth modulation (PWM) converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD). The parallel active filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. The performance of the UPS system is evaluated in three-phase, four-wire systems. Experimental results are presented to confirm the theoretical studies.

A line-interactive UPS system implementation with series-parallel active power-line conditioning for three-phase, four-wire systems

This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with active series-parallel power-line conditioning capabilities. Synchronous reference frame (SRF)-based controller is used to harmonic and reactive power compensation generated from any configuration of non-linear load. Under normal line conditions the UPS system works with universal filtering capabilities, such as compensating the input currents and output voltages. Two three-phase pulse width modulation (PWM) converters, called series and parallel active filters, are used to perform the series and parallel active power-line compensation. The series active power filter works as sinusoidal current source in phase with the input voltage, drawing from utility sinusoidal and balanced input currents with low total harmonic distortion (THD). The parallel active power filter works as sinusoidal voltage source in phase with the input voltage, providing regulated and sinusoidal output voltages with low THD. Operation of a three-phase phase-locked loop (PLL) structure, used in the proposed line-interactive UPS implementation, is presented and experimentally verified under distorted utility conditions. The performance of the UPS system is evaluated in three-phase, four-wire systems. Digital simulations and experimental results are presented to confirm the theoretical studies.

A three-phase line-interactive UPS system implementation with series-parallel active power-line conditioning capabilities

This paper presents a three-phase line-interactive uninterruptible power supply (UPS) system with series-parallel active power-line conditioning capabilities, using a synchronous reference frame (SRF) based controller, which allows an effective power factor correction, load harmonic current suppression and output voltage regulation. The three-phase UPS system is composed of two active power filter topologies. The first one is a series active power filter, which works as a sinusoidal current source in phase with the input voltage. The other is a parallel active power filter, which works as a sinusoidal voltage source in phase with the input voltage, providing to the load a regulated and sinusoidal voltage with low total harmonic distortion (THD). Operation of a three-phase phase-locked loop (PLL) structure, used in the proposed line-interactive UPS implementation, is presented and experimentally verified under distorted utility conditions. The control algorithm using SRF method and the active power flow through the UPS system are described and analytically studied. Design procedures, digital simulations and experimental results for a prototype are presented to verify the good performance of the proposed three-phase line-interactive UPS system.