Cooperative and Dynamically Weighted Model Predictive Control of a 3-Level Uninterruptible Power Supply With Improved Performance and Dynamic Response

Abstract

In this paper, we propose a 3-level double conversion uninterruptible power supply with a new cooperative and dynamically weighted model predictive control technique. A 3-level dc-dc converter is used to improve the dc bus balance and the overall response of the uninterruptible power supply (UPS). A new cooperative model predictive control principle is proposed to enhance the response of multiconverter systems. New controllers are proposed for all converters of the UPS, based on the dynamically weighted model predictive control technique and using the presented cooperative principle. A new power management technique is also proposed for the UPS. The proposed 3-level UPS system presents improved dynamic response and steady-state performance in distinct operating points, when compared to the conventional system. Experimental results demonstrate the advantages of each proposed novelty.Index Terms-Neutral-point-clamped (NPC), optimal switching vector model predictive control (OSV-MPC), predictive control, uninterruptible power supply (UPS). I. INTRODUCTIONU NINTERRUPTIBLE power supplies (UPS) are crucial in critical applications, protecting the load from grid faults and disturbances. Hence, it is important to improve the performance and reliability of these systems.Multilevel converters are largely used in industrial systems, especially the neutral-point-clamped (NPC) topology [1]. However, even though multilevel converters are frequently used in

Fault Analysis and Non-Redundant Fault Tolerance in 3-Level Double Conversion UPS Systems Using Finite-Control-Set Model Predictive Control

“…The ability to control multiple variables simultaneously makes FCS-MPC highly advantageous in systems with multiple concurrent objectives, since it does not require the tuning of several interdependent control loops. FCS-MPC is also advantageous for multi-converter systems, since the controller(s) can consider the cumulative impact of several converters, promoting improved cooperation and system performance [74].…”

“…A cooperative FCS-MPC principle is proposed in [74], to improve multi-converter performance without increasing the overall computational load of the system (compared to independent controllers). This cooperative solution is combined with the dynamically weighted FCS-MPC technique proposed in [77] and applied to a 3-level double conversion UPS system.…”

“…This cooperative solution is combined with the dynamically weighted FCS-MPC technique proposed in [77] and applied to a 3-level double conversion UPS system. The resulting control system proposed in [74] is highly adaptable and promotes high cooperation between all converters of the UPS, improving the overall performance and dynamic response.…”

“…Once again, these techniques focus only on the inverter stage of the UPS and a 2-level topology is used. In [74] a full 3-level UPS system is studied, considering all UPS converters (rectifier, inverter and DC-DC) and all operation modes. In [87,88] FCS-MPC techniques are proposed to control full UPS modules (rectifier+inverter) connected in parallel.…”

Linearized Discrete Charge Balance Control with Simplified Algorithm for DCM Buck Converter

“…Among many strategies, the well-known V 2 controls have been widely used in industrial applications, and they can achieve a great control loop bandwidth [1][2][3]. Predictive controls acquire state variables ahead of time, which allow earlier actions to stabilize the system [4,5]. Adaptive controls can achieve optimized performance in different conditions, which is ensured by online tunings for control parameters [6,7].…”