Load-sharing between two paralleled UPS systems using Model Predictive Control

Oliveira, Tiago J. L.; Caseiro, Luis M. A.; Mendes, André M. S.

doi:10.1109/iecon.2019.8927013

Cited by 5 publications

(8 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given that a fundamental requirement for the correct operation of paralleled UPS systems is the elimination of this current, the main strategies for circulating current elimination in paralleled UPS systems are mainly based on conventional PI control approaches, which typically use a dedicated control loop to eliminate the circulating current [16][17][18]. More recently, strategies for ZSCC suppression in complete three-phase paralleled UPS systems have been proposed using Model Predictive Control (MPC) [3,19]. However, in these works, only UPS systems with a 3-wire configuration at the load-side are studied.…”

Section: Introductionmentioning

confidence: 99%

Model Predictive Control for Paralleled Uninterruptible Power Supplies with an Additional Inverter Leg for Load-Side Neutral Connection

et al. 2021

View full text Add to dashboard Cite

Uninterruptible Power Supplies (UPS) have been demonstrated to be the key technology in feeding either single- and three-phase loads in a wide range of critical applications, such as high-tier datacenters and medical facilities. To increase the overall system power capacity and resilience, UPS systems are usually connected in parallel. When UPS systems are parallel connected, a circulating current can rise, inhibiting correct system operation. Moreover, having a controlled load power distribution is another fundamental requirement in paralleled UPS systems. However, strategies to ensure these two topics have not been explored to date for UPS systems with a load-side neutral connection. This paper proposes an innovative Finite Control Set Model Predictive Control (FCS-MPC) strategy that ensures circulating current elimination and controlled load power distribution for paralleled UPS systems that use an additional inverter leg for load neutral point connection. Additionally, a system topology based on two parallel-connected UPS systems that can simultaneously supply single- and three-phase critical loads is proposed. Experimental results show the effectiveness and robustness of the proposed control techniques even when different types of loads are connected to the UPS systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Model Predictive Control for Paralleled Uninterruptible Power Supplies with an Additional Inverter Leg for Load-Side Neutral Connection

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Moreover, if one system is not able to supply its power target (for example, due to a fault), the other systems must increase their target power, to maintain a correct system operation (but the faulty module can still provide a lower power, instead of being completely deactivated). This can only be achieved through a fully controlled load-power distribution [6].…”

Section: Introductionmentioning

confidence: 99%

“…The faster transient response provided by FCS-MPC compared to more conventional control techniques makes FCS-MPC a very promising control strategy to be used in paralleled UPS systems [6,23]. For example, when a UPS system is not able to supply its power target, the power target of the other systems must be quickly increased, to ensure that the critical load is correctly fed.…”

Section: Introductionmentioning

confidence: 99%

“…More conventional control strategies will face several limitations in this topic. Moreover, the high cooperative principle enabled by FCS-MPC in a complex multi-converter system, such as the one studied in this paper, allows the control action computed for some converters to be considered when choosing the control action of other converters [6,23,32] which can lead to improved overall system performance. This turns FCS-MPC into a technique with enormous potential for example to eliminate the undesired circulating currents that flow between paralleled UPS systems [6,32].…”

Section: Introductionmentioning

confidence: 99%

“…In [23], a cooperative strategy is proposed but just for a standalone UPS system. In the field of paralleled UPS systems, two cooperative based strategies are proposed in [6,32], however in both of these studies the DC/DC converters and respective battery banks were not considered in both paralleled UPS. In [33] a FCS-MPC strategy is proposed for paralleled UPS systems, however it merely addresses the operation of the DC/AC converters in which no circulating current problems exist, which significantly simplifies the required control design.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Finite Control Set Model Predictive Control for Paralleled Uninterruptible Power Supplies

et al. 2020

View full text Add to dashboard Cite

Nowadays, uninterruptible power supplies (UPS) play an important role in feeding critical loads in the electric power systems such as data centers or large communication hubs. Due to the increasing power of these loads and frequent need for expansion or redundancy, UPS systems are frequently connected in parallel. However, when UPS systems are parallel-connected, two fundamental requirements must be verified: potential circulating currents between the systems must be eliminated and the load power must be distributed between the systems according to UPS systems availability. Moreover, a high-quality load voltage waveform must be permanently ensured. In this paper innovative control strategies are proposed for paralleled UPS systems based on Finite Control Set Model Predictive Control (FCS-MPC). The proposed strategies simultaneously provide: controlled load power distribution, circulating current suppression and a high-quality load voltage waveform. A new dynamic converters deactivation mechanism is proposed. This new technique provides improved overall system efficiency and reduced power switches stress. In this paper, two multilevel based UPS systems are parallel-connected. Each UPS contains two three-level Neutral Point-Clamped-Converters (3LNPC) and a three-level DC-DC converter. The presented experimental results demonstrate the effectiveness of the proposed control strategies in several operating conditions.

show abstract

A Novel Machine Learning-Based Load-Adaptive Power Supply System for Improved Energy Efficiency in Datacenters

2021

View full text Add to dashboard Cite

Power Supplies are a key part of the modern Internet and Communications Technologies (ICT) industry. Modern Uninterruptible Power Supply (UPS) systems are modular and as such, consists of several Power Supply Units (PSUs). Various PSU designs are used to optimize efficiency of operation at specific loading conditions, but this engenders inefficient operation at other loading conditions. To optimize the energy efficiency in various loading conditions, this paper proposes a novel power supply multiplexing system engaging different combinations of PSUs, controlled through machine learning techniques to maximize efficiency depending on the loading conditions. Each PSU combination is given a state number. Because of the vast number of combinations (States) that can occur in such systems and due to the redundancy requirements, that need to be met during multiplexing, machine learning techniques are adopted. It is shown that through the novel proposed system an efficiency improvement of over 78% can be achieved in low loading conditions, and an average 5.23% efficiency improvement in all loading conditions.

show abstract

Load-sharing between two paralleled UPS systems using Model Predictive Control

Cited by 5 publications

References 12 publications

Model Predictive Control for Paralleled Uninterruptible Power Supplies with an Additional Inverter Leg for Load-Side Neutral Connection

Model Predictive Control for Paralleled Uninterruptible Power Supplies with an Additional Inverter Leg for Load-Side Neutral Connection

Finite Control Set Model Predictive Control for Paralleled Uninterruptible Power Supplies

A Novel Machine Learning-Based Load-Adaptive Power Supply System for Improved Energy Efficiency in Datacenters

Contact Info

Product

Resources

About