Real-time power loss optimized operation of a solid state transformer by utilizing the common-mode voltage

Large-scale integration of distributed energy resources (DERs) into distribution networks causes topological-operational situations with multidirectional power flows. One of the main components of distribution networks is the power transformer, which does not have the capabilities for real-time control of distribution network parameters with DERs. The use of solid-state transformers (SSTs) for connecting medium-voltage (MV) and low-voltage (LV) distribution networks of both alternating and direct current has great potential for constructing new distribution networks and enhancing the existing ones. Electricity losses in distribution networks can be reduced through the establishment of MV and LV DC networks. In hybrid AC-DC distribution networks, the SSTs can be especially effective, ensuring compensation for voltage dips, fluctuations, and interruptions; regulation of voltage, current, frequency, and power factor in LV networks; and reduction in the levels of harmonic current and voltage due to the presence of power electronic converters (PECs) and capacitors in the DC link. To control the operating parameters of hybrid distribution networks with solid-state transformers, it is crucial to develop and implement advanced control systems (CSs). The purpose of this review is a comprehensive analysis of the features of the creation of CSs SSTs when they are used in hybrid distribution networks with DERs to identify the most effective principles and methods for managing SSTs of different designs, which will accelerate the development and implementation of CSs. This review focuses on the design principles and control strategies for SSTs, guided by their architecture and intended functionality. The architecture of the solid-state transformer control system is presented with a detailed description of the main stages of control. In addition, the features of the SST CS operating under various topologies and operating conditions of distribution networks are examined.

Simulation-Based Interface Characteristic Analysis of Solid-State Transformer System for High-Speed Railway under Railway Power System Faults

Universal Decoupled Equivalent Circuit Models of Solid-State Transformer for Accelerated EMT‐Type Simulation

Innovative electric vehicle charging infrastructure for european transportation electrification: megawatt charging hubs with battery energy storage and solid-state transformers for medium-voltage grid integration.

Voltage Fluctuation Suppression Scheme of Multiport MMC-Based Solid-State Transformer for the Vessel Integrated Power System

Enhanced Protection of Grid-Connected Solid-State Transformers Against Sympathetic Inrush Current

Today’s power grids are being modernized with the integration of new technologies, making them increasingly efficient, secure, and flexible. One of these technologies, which is beginning to make great contributions to distribution systems, is solid-state transformers (SSTs), motivating the present technical and economic study of local level 2 distribution systems in Colombia. Taking into account Resolution 015 of 2018 issued by the Energy and Gas Regulatory Commission (CREG), which establishes the economic and quality parameters for the remuneration of electricity operators, the possibility of using these new technologies in electricity networks, particularly distribution networks, was studied. The methodology for developing this study consisted of creating a reference framework describing the topologies implemented in local distribution systems (LDSs), followed by a technical and economic evaluation based on demand management and asset remuneration through special construction units, providing alternatives for the digitization and modernization of the Colombian electricity market. The research revealed the advantages of SST technologies, such as reactive power compensation, surge protection, bidirectional flow, voltage drops, harmonic mitigation, voltage regulation, size reduction, and decreased short-circuit currents. These benefits can be leveraged by distribution network operators to properly manage these types of technologies, allowing them to be better prepared for the transition to smart grids.

Solid-state transformer: The catalyst for resilient and sustainable smart grids

Reserved-Energy-Aided Control in Solid-State Transformers

Optimal allocation and technoeconomic analysis of solid state transformer in distribution network

An Optimized Fault-Tolerant Control Strategy Based on Dynamic Modulation Voltage Adjustment for Solid-State Transformers

Abstract This paper presents a high‐power‐density solid‐state transformer (SST) designed for 25 kV alternative current railway applications, delivering a 3 kV direct current output to traction inverters. The SST is composed of sub‐modules with the adoption of 1.7 kV insulated gate bipolar transistor and SiC metal oxide field effect transistor (MOSFET) in an input‐series–output‐series structure, providing higher power density than conventional topologies that rely on high‐voltage switches (>1.7 kV). Because these high‐voltage SiC MOSFETs are still expensive and not fully commercialised, the proposed approach offers a more cost‐effective alternative. A total of 42 converter cells ensure a highly modular and scalable design, with precise synchronisation and high‐speed control achieved through an EtherCAT‐based communication network. Additionally, a distributed control algorithm is introduced, mitigating excessive dependence on the communication link for module‐level operations. The effectiveness of the entire system—including the design and control schemes—has been experimentally verified, ranging from individual converter cells to a reduced SST prototype of up to three sub‐modules. These results confirm the feasibility and advantages of the proposed SST in terms of power density, cost efficiency and reliability for railway traction applications.

Solid-State Transformer (SST)-Based High-Frequency MV Propulsion Drive With New Modulation Technique

Numerical Analysis of Partial Discharge Ignition in H₂ Bubbles Floating in Dielectric Oils, for High-Voltage Solid State Transformer Applications

Performance evaluation of single-phase solid-state transformer for high-speed railway propulsion

Power network reliability and safety are severely compromised by voltage fluctuations and power mismatches brought on by the dispersed, unpredictable, and intermittent nature of distributed energy resources as well as by variations in demand. In order to address this problem, this study presents the architecture of a Power Electronic Transformer- based AC/DC hybrid microgrid. Being capable of adequate control coordination ensures the system's steady and dependable functioning. To successfully reduce DC bus voltage fluctuations while scheduling power flow across energy storage, AC microgrid, DC microgrid, as well as solid- state transformers, an energy management technique is suggested. We provide a new adaptive droop control over energy storage that may maximize the economic value to customers while extending the life of supercapacitors. This droop coefficient can be determined using a fuzzy logic controller. It takes as input parameters the projected super capacitor charge state as well as unit-time electricity charge. The suggested energy management and control technique is validated via simulation. Key Words: hybrid micro grid, SST, Fuzzy logic control, ANN, Energy management strategy

Modularized Diode Rectifiers: A New Family of Solid-State Transformers

Design and performance evaluation of a battery-integrated PV system utilizing triple-active bridge based solid-state transformer topology

This paper presents a photovoltaic system connected to a solid-state transformer (SST). The PVs are integrated into the low-voltage DC (LVDC) link. The SST consists of three stages containing combinations of converters: the modular multilevel converter MMC is employed in the medium voltage (LV) stage, the DC-DC converter is applied in the isolated stage, and a three-phase inverter is utilized in the low voltage (LV) stage. To ensure the smooth integration of PVs, it is essential to maintain a stable voltage at the LVDC level. To this end, the application control of the DC-DC converter must be used. The single-phase shift control (SPS) strategy was adopted. This control strategy maintains DC voltage levels at appropriate values and enables bidirectional power flow. In addition, to optimize the extraction of maximum power from the PVs, a maximum power point tracking (MPPT) technique is applied based on the M5P model decision tree. In parallel, to ensure optimal operation of the SST, a voltage-oriented control (VOC) and voltage capacitor balancing algorithm based on rotating gating signals is implemented for the MMC converter. In contrast, an unbalanced load control is applied to the inverter. The model developed in this study was implemented in MATLAB/Simulink, and the system's dynamic performance was validated.