The Future of Electrical Power Grids: A Power Electronics-Based Approach
Grids of electric power
Power networks are constantly evolving in several areas of actuation, including production, transportation, and distribution, with the goal of assuring worldwide access to electrical energy. This change has been increasingly visible in the previous several decades. Despite early efforts to construct dispersed power networks, centralized power grids have come to dominate. Since the outset, and in tandem with the natural growth of power networks, real-time stability in the production and consumption phases has been regarded as a top concern. In this regard, efforts have been concentrated on controllability, dependability, cost reduction, and efficiency over several decades; nevertheless, sophisticated technologies are developing for a sustainable and resilient future of power grids.
Furthermore, numerous technologies have emerged and are acquiring dominance, creating a set of relevant synergies among various fields. A discussion of the merits, downsides, problems, and limits of multilayer power management systems for future power grids. A future power grid design that involves large-scale integration of dispersed energy resources while guaranteeing autonomy and controllability in the production and consumption phases is examined. The significance of blockchains, machine learning, and deep learning technologies for future power grids, highlighting the significance of themes such as security, cyber-physical assaults, and defensive strategies.
These issues are intertwined with power grid management and, in some ways, should be prioritized because radical changes in the large-scale incorporation of technologies in power grids (for example, electric mobility, renewables, controllable electronic loads, and storage systems) are sought. As a result, power grid transformation is a dynamic process that will be actively invested in over the next few decades to support the increasing penetration of new technology. Indeed, the transition from centralized to decentralized production is currently beginning, and this is being characterized as a new and important radical change in power grids.
Along with such improvements, there is a continuing revolution in power flow, with bidirectional operation increasingly being used to create new solutions, not only in management, but also in power electronics systems. A viewpoint on the usage of power electronics to aid the adoption of renewables. A look at power grid technologies, infrastructure, and obstacles for broad renewables integration in offshore environments. Such concerns will be thoroughly investigated in the coming decades, as will extremely effective attempts to govern the advancement of power electronics technology.
This scenario of ongoing development to supply more intelligent electricity networks gives rise to the often referred to as "smart grids," and so-called "future smart grids" are also gaining popularity. In such a situation, end users assume active engagement, opening up new possibilities for the power grid in terms of consumption, storage, and supply, a model known as "prosumers."
Power grids are shifting from a centralized to a decentralized model as new technologies are integrated. Microgrids are also gaining traction in this environment, allowing the integration of local distribution networks with production, storage, and regulated loads. Furthermore, microgrids provide the option of functioning with a coordinated and regulated approach, thus they may run by being linked to the main power grid or independently, providing totally autonomous operation . A microgrid analysis, highlighting robustness, resilience, and energy efficiency, as well as potential and difficulties. A comprehensive examination of power electronics techniques and control strategies for AC/DC microgrids.
According to this viewpoint, specialized control techniques and synchronization methods, such as remote microgrid synchronization, adaptive synchronization methods, and advanced synchronization controllers among power converters, assume a relevant dominance for a variety of reasons. Conventional substations are evolving as a result of new power electronics technology, as are forthcoming DC power grids. An assessment of multilevel converters developed for grid-connected systems, emphasizing the critical role of power electronics.
Figure 1 depicts a collection of future power grid technologies, highlighting the interface maintained by hybrid AC/DC power grids, which are formed by solid-state transformers (SSTs). Renewables (e.g., solar PV panels and wind turbine technologies) in onshore and offshore conditions, energy storage systems, electric mobility (e.g., on-board and off-board chargers allowing bidirectional operation controlled by the user and grid management technology), hydroelectric systems, and factories and homes (conventional and smart factories and homes) are among the technologies highlighted. There are several publications in the present literature focused on hybrid AC/DC power grids as well as the function of the SST; however, a complete work focusing on the definitive role of future power grids is lacking. In this work, which presents a background for future power grids, the most important sources accessible in the literature are adequately described and linked.
Figure 1 depicts technologies that will be used in future electrical power systems.
This perspective paper's main contribution is the illustration of a power electronics-based path for future power grids, with a focus on a path supported by hybrid AC/DC grids and SSTs. Throughout the study, such technologies are contextualized separately in terms of their position in future power grids and their interaction. The second section discusses the significance of hybrid AC/DC power networks, covering important difficulties and design frameworks. Section 3 introduces the use of SSTs in the establishment of hybrid AC/DC power grids, demonstrating its undeniable significance in the context of future power grids. Section 4 discusses the significance and contextualization of unified power electronics systems with numerous operations for future power grids, allowing for functional optimization while minimizing the number of power converters, especially AC-DC. The key results are summarized in Section 5.
2. AC/DC Hybrid Power Grids
As an alternative to existing AC grids, new DC-based power networks are developing, posing significant difficulties and potential. The dispute between Edison and Tesla/Westinghouse demonstrates the history of AC grids. AC networks were successful because of the use of power transformers, which simplified changes in voltage levels and facilitated power transmission and distribution. Because most electrical equipment is intended to work in alternating current (AC), this advantage remains. Nonetheless, given the technical advances in power electronics and the fact that many devices now operate in DC, DC grids are projected to continue to gain prominence. Renewables (mostly supported by solar PV), energy storage systems (primarily supported by batteries), and electric mobility systems all necessitate the use of batteries.
Renewables (mostly solar PV), energy storage systems (primarily batteries), and electric mobility systems all require a DC interface; hence, DC grids are a potential method for establishing a direct link. DC grids are a viable solution because (i) solar PV is becoming more prevalent in various sectors; (ii) batteries are frequently used as storage applications; (iii) lighting systems are generally based on LED technologies; (iv) electric mobility systems use batteries as storage systems; (v) power quality issues are alleviated; (vi) power stages based on power electronics are significantly reduced; and (vii) passive AC-DC rectifiers are eliminated. However, an extreme step is required.
However, a complete transition from AC to DC grids is not feasible; so, integration of AC and DC grids is desirable. This has been performed for a variety of scenarios and is known as "hybrid AC/DC grids." provides an evaluation of power electronics converters dedicated to satisfying the demands of DC grids. In conclusion, the benefits of hybrid AC/DC grids are obvious and undeniable, and they may also play an important role in the residential sector (e.g., smart houses); hence, their position in future power grids is clear. Various initiatives utilizing hybrid AC/DC grids have been completed or are under underway across the world, showing the substantial attention they will receive in the next decades. Despite the benefits of DC grids and the speedy transition to a new system, DC grids nevertheless pose obstacles, mostly owing to standardization, grid codes, and protective protocols.
When it comes to DC grid topologies, there are two primary options: unipolar and bipolar. The bipolar structure requires three wires and is more difficult in terms of both control and hardware, but it allows for operation on three voltage levels, which is important for the integration of DC technologies that operate with separate voltage levels. Furthermore, if a fault develops in one wire, the operation may be maintained; similarly, a unipolar DC grid, since it is just a section of the grid, will be impacted by the fault. A thorough examination of interesting technology relating to bipolar DC grids.
However, voltage imbalances induced by imbalanced loads can arise in bipolar DC grids, hence power electronics converters are critical for assuring balanced power consumption and the stability of the bipolar DC grid.
The setup of a hybrid AC/DC grid must be developed to achieve critical features while taking into account the connected technologies. Figure 2 depicts a hybrid AC/DC grid design. The main distinction between hybrid AC/DC grid structures is whether the grid is AC-coupled or AC-decoupled. In the case of a coupled AC, a transformer is used to connect the main AC grid to the internal AC grid, which is accomplished by the hybrid AC/DC grid. In this instance, the use of power electronics converters is required for the formation of the DC grid. In the case of a decoupled AC, at a bare minimum, a single AC-DC and a single DC-DC power converter are required. In this situation, connecting the AC to the main AC grid is performed via AC-DC and DC-AC power stages, ensuring isolation in both the AC and DC grids.
Figure 2 shows the components of a hybrid AC/DC grid.
3. Solid-State Transformer
Low-frequency power transformers are derived from alternating current power networks and are still utilized in transmission and distribution. Nonetheless, as the number of technologies and actors connected to power grids grows, new issues in delivering accurate and quick controllability emerge. In this context, the importance of power electronics in meeting growing technological demands is obvious, especially given the opportunity provided by replacing low-frequency transformers with SSTs, which provides controllability and support for supplementary services at both the transmission and distribution levels. SSTs have seen significant expansion in terms of topologies and applications in recent years, showing that they will play an important role in future power grids.
Given the versatility of SSTs, the idea of hybrid AC/DC grids supported by SSTs is also acknowledged in the context of future power grids. The capacity of an SST to produce extra characteristics, such as hybrid AC/DC grids, illustrates its ability to interface with technologies that operate in a native DC mode. SST created for building hybrid AC/DC grids that provides synchronized management of power and voltage. A hybrid SST that connects MVDC and LVDC grids. A unique modulation and control technique for an SST with a modular converter layout is presented. An SST for connecting renewables to PV panels through DC connections.
A modular SST designed specifically for EV battery charging stations. The implementation of an SST has proven to be an intriguing task, as it necessitates the use of several power electronics technologies. The design and control of high-frequency converters for the next generation of SSTs based on SiC power devices. Soft-switching control algorithms have been developed particularly for SSTs. A revolutionary high-frequency SST design that uses fewer switching components. A matrix power electronics converter-based SST.
Concerning the role of SSTs in future power grids, the alignment of important industrial actors and market growth is extremely helpful, with a particular emphasis on businesses like as ABB, Siemens AG, and Schneider Electric SE. Furthermore, given the SST's continual progress, the SST market will gain further value in the next decades. Comprehensive evaluations with qualitative and quantitative analysis of conventional and SST solutions, as well as a framework for an SST with virtual synchronous machine functions. Figure 3 depicts an SST used to connect high-voltage AC (HVAC) and high-voltage DC (HVDC), as well as low-voltage AC (LVAC) and low-voltage DC (LVDC), allowing the establishment of hybrid AC/DC grids.
Figure 3: An SST used to connect high-voltage AC and DC grids (HVAC and HVDC) and low-voltage AC and DC grids (LVAC and LVDC), allowing the formation of hybrid AC/DC grids.
4. Multi-operational, unified power electronics systems
As previously said, power grids are moving toward the integration of more regulated technologies; however, other technologies, including power conditioners, may also be taken into consideration. Therefore, to reduce grid disruptions, unified control solutions for power electronics are important. When it comes to power management, the interdependence of renewable energy sources and electric mobility systems creates revolutionary conditions. Controlled energy storage from electric vehicle batteries, along with the utilization of this energy when it benefits both the user and the grid, is acknowledged as a critical component of power grid stability and sustainability. As a result, targeted control strategies for renewable energy and electric mobility are crucial, given the numerous
As a result, specialized control techniques dedicated to both electric mobility and renewables are critical in terms of diverse power profiles, prices, and the influence on power quality. Such points of view are well-known, but the role of power electronics cannot be overlooked, because new radical practices in hardware structure can be implemented without jeopardizing the individual operation of electric mobility systems or renewables, while also providing new opportunities for the power grid. As a result, technologies for integrating battery chargers and renewables specifically dedicated to such interfaces have already been identified, allowing the integration of storage technologies and decreasing the number of power stages in AC and DC conversion, with inherent benefits such as cost reduction and efficiency increase.
We discover linkages between the AC-DC converters by evaluating these vectors, enabling for the growth of power converters toward unified power electronics topologies with natural properties such as greater efficiency and lower costs, weight, and volume. Power quality enhancement, a direct interface of renewables to the DC link without power converters, and a unified topology with multiple power converters for optimizing each interface and compensating for all power quality problems related to current are all important topics of research for future power grids.
With a focus on the future of power grids, it is expected that unified power electronics with multiple operations will ensure a single power grid interface, in single-phase or three-phase connections, involving technologies of electric mobility, renewables, and power quality features; four-quadrant active/reactive power operation on the AC side; unidirectional/bidirectional power operation on the DC side, even without the AC interface (e.g., direct connect). Figure 4 depicts a design of unified power electronics with numerous operations for future power grids, where Figure 4a depicts the shared operation of power grids, electric cars, and renewables, enabling or restricting the increase in power quality.
Figure 4b shows the direct linkage of power grids and electric vehicles, allowing or prohibiting power quality improvement; Figure 4c shows the direct linkage of power grids and renewables, allowing or prohibiting power quality improvement; Figure 4d shows the direct linkage of electric vehicles and renewables; Figure 4e shows power quality improvement based solely on the unified system, excluding the linkage of electric vehicles.
Figure 4: Diagram of future power grids' combined power electronics with numerous operations: (a) Shared operation of power grids, electric vehicles, and renewables, allowing or prohibiting power quality improvement; (b) direct linkage of power grids and electric vehicles, allowing or prohibiting power quality improvement; (c) direct linkage of power grids and renewables, allowing or prohibiting power quality improvement; (d) direct linkage of electric vehicles and renewables;
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