Microgrid's regulation using a multiport SST

Microgrid's regulation using a multiport SST | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Microgrid's regulation using a multiport SST Juan M Ramirez, Francisco J Arizaga-Ayala, Janeth A. Alcala This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2592578/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A solid-state transformer controlled by a virtual synchronous generator is presented as an element capable of increasing the flexibility of electrical power distribution in a modern grid. With the advent of microgrids, the choice of strategies and devices capable of giving them flexibility has been of paramount importance. Emphasis has been shown on the transformer characteristics to regulate the frequency and voltage at its output terminals. This is very suitable for driving a wind turbine. Results are presented that demonstrate the versatility of such features working together. Power electronics Power electronic transformer Solid-state transformer Synchronverter Virtual synchronous generator Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 1. Introduction Power converters can be used to modernise electrical power supply systems. The solid-state transformer (SST) plays an essential role in this context. This is a compact medium- or high-frequency power converter with a high power density. Global warming, the depletion of non-renewable energies, and the price reduction of renewable energy sources have led to the need for solid-state transformers (SST). The latter is the power electronic transformer (PET), which exhibits high-frequency characteristics, bidirectional power flow, and electrical isolation. Thus, future smart grids could rely on the solid-state transformer (SST). It has several positive features for controlling the electrical energy flow and adding functions to the distribution grid as reactive power management by handling voltage drops. However, all these functionalities increase operational complexity. According to different power conversion requirements, there are additional cascaded PET or SST topologies, such as AC-AC or AC-DC-DC-AC, for instance. Except for the first one, other topologies commonly include a DC-DC stage. This is used to achieve DC voltage conversion, power bi-directionality, and electrical isolation [ 1 ]. Such converters become attractive because their voltage gain ratio may be accommodated by the transformer. Among the bidirectional converters, dual active bridge voltage-fed converters (DAB) are helpful due to their performance and simplicity advantages. The DAB is often utilised at the intermediate stage of the electronic transformer because it provides good performance and a small current. A new bidirectional high voltage gain isolated soft-switched DC-DC converter (IBDC) using dual PWM may also be used [ 2 ]. The required high voltage gain may be attained by voltage and current doubler. A bidirectional boost converter modulates the rectified voltage to the desired level while transferring power. The virtual synchronous generator (VSG) is a strategy for handling the switches that makeup voltage source converters (VSCs), which is simple to implement, provides excellent performance, and becomes very attractive in modern power electronics applications [ 2 ]. Conventional VSG modeling comes from mimicking the induction of an electromotive force in a synchronous machine. Such signals play the role of modulating signals in a pulse width modulation (PWM) strategy. In this letter, an SST is controlled by a VSG. The analysed topology becomes an SST encompassing a three-phase rectifier, the DAB element, and a PWM inverter. The rectifier and the inverter are driven by VSG [ 2 ], Fig. 1 . Notice that the scheme under analysis has three incoming or outgoing ports [ 3 ], which provides greater flexibility to a grid. With such an arrangement, it is possible to control the power flow from two ports to the third or from one to the other two; bi-directionality is essential in the scheme. Furthermore, the analysis demonstrates that the virtual synchronous generator can correctly handle such a topology. This letter focuses on using control based on the virtual synchronous machine concept (VSG) for handling power flows between different power systems in a microgrid. An SST is used to link such systems. The contribution of this letter lies in the fact that it proposes a way to make the distribution of electrical energy more flexible using an SST controlled by VSGs, achieving the desired objectives. 2. Vsg Control Here we use a currently attractive approach when mentioning micro- and nano-grids, including the insertion of renewable technologies. There is usually an electronic inverter as a means of interconnection to the utility. One solution that can help stabilise such interconnections is to provide additional inertia virtually. Virtual inertia can positively support installations with distributed generators (DG)/renewable energy sources (RES) using short-term energy storage with a power electronics inverter/converter and an appropriate control mechanism. This concept can be described as a virtual synchronous generator (VSG) or synchronous virtual machine (VISMA). The concept of the virtual synchronous generator (VSG) is to mimic the behaviour of a synchronous machine by controlling a power electronic converter. Thus, VSGs are based on a descriptive model of a synchronous machine. Emulating inertia is a feature of all VSG control schemes, and the desired approximation in reproducing the electro-mechanical dynamics can vary. At the same time, other aspects, such as electrical transients, can be included or neglected. If the purpose of the VSG is to replicate the dynamic behaviour, a full-order model of the generator must be included. This includes a fifth-order electrical model with the representation of different windings and, in addition, a second-order mechanical model. Several control schemes have been reported for the VSG, which is the interface between the synchronous generator models and the electronic converter, among them the one proposed in [ 2 ], which in the authors' opinion, represents a good compromise between accuracy and simplicity, Fig. 2 . In this letter, a VSG model, Fig. 3 , is utilised to generate triggers for the power switches in the rectifier-inverter arrangements in Fig. 2 , the interface to grids A, B and C. In this case, the application is made by defining two reference signals ( Pset and Qset , active and reactive power) in the case of the inverters and ( Qset and Vdc , reactive power and dc voltage) for the rectifier. 3. Active Bridge Behaviour Under Voltage Variations Figure 4 shows a programmable AC signal input. The signal's frequency changes from 60 Hz to 70 Hz and its amplitude varies between 500 V and 700 V. This signal tries to emulate the type of events that can occur in an unregulated wind turbine. Changes in its frequency and amplitude are magnitudes that occur regularly in systems of this type. Figure 5 displays the corresponding output. Note that this is to maintain a constant line-to-line voltage at 60 Hz. However, if the input signal drops below its nominal voltage, the DAB will not be able to maintain a continuous output signal. Concerning frequency, it does not matter if the frequency of the input source varies. This is due to the output connection of the dc-dc converter to the inverter stage. The dual active bridge transfers the most power with a 90° phase shift. However, a significant phase shift requires a high leakage inductance to transmit power. The use of high inductance results in increased currents on the primary and secondary sides of the transformer, which reduces the converter's efficiency. Table I summarises some electrical specifications of the dc-dc converter for this simulation. Table I. Electrical parameters of the dc-dc converter. Phase shift -0.78 < Ø < 0.78 (rad) Total leakage inductance 19.5 µH PMW switching frequency 100 kHz Turns Ratio 1:0.6 Input voltage 1000 V Output Voltage 600 V Power Output 10 kW Eficiency Peak 85% The converter signals are controlled using the block diagram in Fig. 6 , where a difference between the reference voltage and the desired voltage is observed. This difference constitutes the error signal regulated by a PID that intervenes in the signals' phase angle. Similarly, the difference between the reference current and the output current is used to correct the signal by adjusting the phase angle of the pulses. The primary and secondary signals are shown in Fig. 7 . It can be seen that the secondary signal is out of phase with the primary signal. Similarly, the leakage current of the high-frequency transformer is measured. The DAB allows the frequency to be kept stable, as shown in Fig. 8 a. After a short period of transient variation, the DAB returns to its nominal value of 60 Hz and remains there regardless of whether the frequency or input voltage changes. The specifications in Table I illustrate the construction of a dc-dc converter with 10 kW of output power and a phase angle of 45 degrees. Figure 8 b depicts the output signals of the input power of the dc-dc converter (blue) and the converter's output (red). For resistive loads, the efficiency of the converter is between 80 and 85 percent. 4. Case Studies The case study is intended to demonstrate the enormous possibilities of flexibility in power supply that can be achieved with modern devices such as the electronic transformer controlled with a VSG scheme. It assumes an arrangement linking three grids, Fig. 1 . These can represent a utility, a generator, or a renewable energy source, for example. The simulated events described in the following demonstrate the benefits of this modern equipment. During the entire study time, network C kept demanding 20 kW. Grid B does not deliver or require energy during the interval t = [0, 2) s. Thus, meanwhile, A supplies the demand of C plus losses. At time t = 2 s, grid B demands 25 kW and continues until time t = 4 s. During such an interval, grid A is in charge of supplying all the energy required. Finally, at t = 4 s, grid B starts to provide 25 kW so that it is sufficient to satisfy the demand of 20 kW by C , and the surplus is delivered to grid A , Fig. 9 ( a ). Regarding reactive power management, the three VSG's controls set the reactive power reference at zero, Fig. 9 ( b ). Figure 9 (c) first illustrates the rectifier's DC voltage behaviour. The second and third images are the voltages at the B and C terminals; note tolerable transients when changing conditions. Developing new magnetic materials that handle high flux densities and frequencies with lower losses is suitable for creating efficient SSTs. In addition, the advent of distributed generation and the development of intelligent microgrids encourage this type of technology. Double active bridge (DAB) converters are employed in the converter, using the leakage inductance transformer as the inductance. This reduces the volume since including a coil is not required, improving the system's efficiency. In DAB elements, phase shifting transfers power from one port to another. As can be seen in reference [ 1 ], in most of the known SST topologies, a PWM strategy is used to manage them. This results in reliability and simplicity. Aspects are highly sought after in complex topologies such as the subject of this letter. These aspects tie in very well with the VSG-type control chosen here. Especially maintaining a unity power factor can be advantageous for grid operation. In this type of controller, the active and reactive power values are used to compare their reference values. Finally, those will depend on the measured values of voltages and currents. Practical, robust, and fast sensors that perform their work almost instantaneously are now available, making this sensing stage very reliable. Furthermore, the implementation of the VSG strategy is very affordable through cheap and reliable development boards and low-cost and fast FPGAs. Thus, the proposed control scheme can be implemented relatively simply and efficiently. The simulation results show that the proposed scheme can effectively handle power flows in a microgrid. Moreover, the VSG strategy is quite convenient when defining reference active and reactive power values for flexibility management in the network. 4.1. Frequency behaviour Note that in the system studied, two networks operate at 60 Hz, and a third operates at 50 Hz. This highlights the possibilities of this type of transformer. It is important to note that two systems operate at 60 Hz, while the third system operates at 50 Hz, thus highlighting the possibilities of this type of transformer. It is important to note that the main changes occur in network B (network C consumes energy, but in this study, it does not change its level of consumption). Thus, networks A and C show practically no noticeable variations in frequency, as shown in Figs. 10 ( a ) and 10( c ). This is not the case for network B, where the changes in demand are experienced, Fig. 10 ( b ). Note that the frequency varies momentarily, but after a short time, it returns to its nominal state of 50 Hz. The rapidity at which the frequency returns depends on the controllers' parameters (which, in this case, have not been optimised), the capacitors' size, and other factors. This makes the electronic transformer attractive for this purpose, as it can achieve a constant frequency response. 4.2. Frequency fluctuations In this section, network A undergoes ramped variations in frequency (0.25 Hz/s rise and fall). The aim is to verify the robustness of the device to this type of event by confirming what happens in networks B and C when these events occur. Figure 11 (increase in frequency in network A) and Fig. 12 (decrease in frequency in network A) show that, despite these variations in frequency, the behaviour of networks B and C is similar to that expected. That is to say that network B experiences transients in its frequency due to the change in demand and that network C keeps its frequency constant. This is a transformer's desirable feature, as it is expected that some of the networks may be connected to wind generation, for example. 4.3. Reactive power handling This section studies the behaviour of reactive power in the different ports of the device. It should be noted that in all three networks, the reactive power delivery has been set at 0 VARS. Thus, Figs. 13 – 16 show the reactive power variations in response to changes in the voltage of network A, including the variations in the demand of network B, already described. The latter is ramped with a 0.025 V/s ratio. Notice how the voltages in networks B and C vary and the reactive power in the three ports. Note that the reactive power exhibits a higher sensitivity than that associated with the active power, although the control tries to keep it at 0 VARS average. Voltage variations in port A have practically no impact on the corresponding voltage in ports B and C. The effect of demand variations in network B on the reagents of the three ports is more noticeable. 5. Conclusions The solid-state transformer is a grid element that provides advantageous flexibility to the operation, mainly due to its bidirectional capacity that uses converters such as the dual active bridge that assumes an essential role in the device. The bidirectional power flow characteristic is a determining factor in distributed generation schemes. The networks may be operated by modifying the flow direction, depending on various factors, such as the timetable and energy availability, for instance. Active and reactive power flow controllability may be achieved by employing a virtual synchronous generator strategy, which has proven in this and many other applications to have attractive characteristics for managing DC-AC converters or vice versa, mainly in terms of its ease of implementation and appropriate performance to achieve the specified reference values. As verified, the device can maintain voltage and frequency values around its nominal specifications, despite slow variations of such signals at a port, making it very attractive for applications with power injections at different points in the network. For these reasons, this paper proposes the joint use of both strategies to coordinate the flows in a microgrid and thus provide operational flexibility. Declarations Ethical Approval Not applicable Competing interests the author has no competing interests Authors' contributions Not applicable Funding the work was carried out with the support of the Consejo Nacional de Ciencia y Tecnología -México, under the project FSE-2013-05-246949. Availability of data and materials If you are interested in the database used, please contact the author. References M. A. Hannan et al., "State of the Art of Solid-State Transformers: Advanced Topologies, Implementation Issues, Recent Progress and Improvements," in IEEE Access, vol. 8, pp. 19113-19132, 2020, doi: 10.1109/ACCESS.2020.2967345. Q.-C. Zhong, Synchronverter Based Generation, in Power Electronics-Enabled Autonomous Power Systems: Next Generation Smart Grids , Wiley-IEEE Press, 2020. J. Posada Contreras, J. M. Ramirez, "Multi-Fed Power Electronic Transformer for Use in Modern Distribution Systems". IEEE Transactions on Smart Grid, Vol. 5, No. 3, May 2014, pp. 1532-1541. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2592578","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":177021460,"identity":"0db42dbc-5378-48d3-93ce-38df679604ba","order_by":0,"name":"Juan M Ramirez","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA60lEQVRIiWNgGAWjYBACxgYQaQDE7A0MB0jUwnMAooWHePskEiA0QS3M7b0PP90ouCcnP/Pxw8OFbTb29uxnDJhutuFxWM9xY+kcg2JjxtlpBodntqUl9vDkGDDnnMGjZUYaA1BLQmKzdA7DYZ4zhxN4GNISmHMq8Gph/g3UUt8meQak5b89D/8zoBYDvFrYQLYk8EjwALVUHGDskUg+gN+WnmNs1kAthjN4gH7hqUhO7Lnx+MBhfH4xbG9jvp3zJ0Fevv3w4888Bnb27P2JjY9z8YSYYQM20QO4NTAwyOOTHAWjYBSMglEABgCfhkttvUbjSgAAAABJRU5ErkJggg==","orcid":"","institution":"Center for Research and Advanced Studies of the National Polytechnic Institute","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Juan","middleName":"M","lastName":"Ramirez","suffix":""},{"id":177021462,"identity":"16520c44-db11-439c-ae1a-c507231c7c0c","order_by":1,"name":"Francisco J Arizaga-Ayala","email":"","orcid":"","institution":"Center for Research and Advanced Studies of the National Polytechnic Institute","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Francisco","middleName":"J","lastName":"Arizaga-Ayala","suffix":""},{"id":177021463,"identity":"96119ad9-c126-4351-b6cd-c9ac5006c394","order_by":2,"name":"Janeth A. 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(b) DAB's input-output active power.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/6e93d40c635743ad3f2d8bb8.png"},{"id":33185929,"identity":"d7fdb5c7-1b94-404a-9719-d3dd9c310cb3","added_by":"auto","created_at":"2023-02-20 16:03:55","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":572243,"visible":true,"origin":"","legend":"\u003cp\u003eGrids \u003cem\u003eA\u003c/em\u003e, \u003cem\u003eB\u003c/em\u003eand \u003cem\u003eC\u003c/em\u003e: \u003cem\u003e(a)\u003c/em\u003e active power; \u003cem\u003e(b)\u003c/em\u003e reactive power; \u003cem\u003e(c)\u003c/em\u003evoltage magnitude.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/7d30c0a0304c42ce78fa7617.png"},{"id":33186298,"identity":"eaf80644-1ba3-4b6c-a3e2-4d89f67630e3","added_by":"auto","created_at":"2023-02-20 16:11:55","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":152144,"visible":true,"origin":"","legend":"\u003cp\u003e(from top to bottom) frequency behaviour for the events described in Fig. 9: (\u003cem\u003ea\u003c/em\u003e) grid A; (\u003cem\u003eb\u003c/em\u003e) grid B; (\u003cem\u003ec\u003c/em\u003e) grid C.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/c15d79ab372e9bea0d3f369b.png"},{"id":33184929,"identity":"535e5fa2-e6aa-4ef0-a2e5-3d9ce7dc1cdd","added_by":"auto","created_at":"2023-02-20 15:55:55","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":133183,"visible":true,"origin":"","legend":"\u003cp\u003e(from top to bottom) behaviour for the increment in grid A frequency and demand modifications in grid B: (\u003cem\u003ea\u003c/em\u003e) grid A; (\u003cem\u003eb\u003c/em\u003e) grid B; (\u003cem\u003ec\u003c/em\u003e) grid C.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/d5731a6925042741dc7fd695.png"},{"id":33184928,"identity":"4b0e43b9-f995-48bd-8b10-a394162e67e0","added_by":"auto","created_at":"2023-02-20 15:55:55","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":112804,"visible":true,"origin":"","legend":"\u003cp\u003e(from top to bottom) behaviour for the decrement in grid A frequency and demand modifications in grid B: (\u003cem\u003ea\u003c/em\u003e) grid A; (\u003cem\u003eb\u003c/em\u003e) grid B; (\u003cem\u003ec\u003c/em\u003e) grid C.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/0a292dd332bf4e23ab1e43fb.png"},{"id":33184936,"identity":"0bf94d0d-4c4b-4424-bbed-748fc7ee2915","added_by":"auto","created_at":"2023-02-20 15:55:55","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":640409,"visible":true,"origin":"","legend":"\u003cp\u003eThree-phase voltages at the three ports. In grid A, a rise occurs after 2.5 s, and demand changes in grid B are considered from top to bottom (\u003cem\u003ea\u003c/em\u003e) network A, (\u003cem\u003eb\u003c/em\u003e) network B, (\u003cem\u003ec\u003c/em\u003e) network A.\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/4f97dc8b53479b33ac96ddd3.png"},{"id":33186786,"identity":"ea69c68a-41da-478d-bcb1-fe2077e7ea63","added_by":"auto","created_at":"2023-02-20 16:19:55","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":113634,"visible":true,"origin":"","legend":"\u003cp\u003eReactive power behaviour at the three ports for the conditions described in Fig. 9. The control objective is to keep the reactive power at 0. From top to bottom, (a) network A, (b) network B, (c) network C.\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/4582800ec7c0903888c743c0.png"},{"id":33184935,"identity":"a503b8b2-fba7-49d7-8d35-c1af595f04ad","added_by":"auto","created_at":"2023-02-20 15:55:55","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":693202,"visible":true,"origin":"","legend":"\u003cp\u003eThree-phase voltages at the three ports. In grid A, a drop occurs after 2.5 s, and demand changes in grid B are considered from top to bottom (\u003cem\u003ea\u003c/em\u003e) network A, (\u003cem\u003eb\u003c/em\u003e) network B, (\u003cem\u003ec\u003c/em\u003e) network A.\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/480e7f74d0c17cb3497d84dd.png"},{"id":33187393,"identity":"5207283a-9a91-4737-a8e3-8fa739fdb4ea","added_by":"auto","created_at":"2023-02-20 16:27:55","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":115088,"visible":true,"origin":"","legend":"\u003cp\u003eReactive power behaviour at the three ports, for the conditions described in Fig. 9. Three-phase voltage in grid A is descending. From top to bottom, (\u003cem\u003ea\u003c/em\u003e) network A, (\u003cem\u003eb\u003c/em\u003e) network B, (\u003cem\u003ec\u003c/em\u003e) network C.\u003c/p\u003e","description":"","filename":"16.png","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/e97b7cd27e6148858b9d5796.png"},{"id":39745906,"identity":"1701c4b4-d8db-403e-b1bf-8b907f195e6a","added_by":"auto","created_at":"2023-07-09 06:44:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2840823,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2592578/v1/b21e48d1-52c7-4bdb-b75e-a48c500d4b24.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Microgrid's regulation using a multiport SST","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePower converters can be used to modernise electrical power supply systems. The solid-state transformer (SST) plays an essential role in this context. This is a compact medium- or high-frequency power converter with a high power density.\u003c/p\u003e \u003cp\u003eGlobal warming, the depletion of non-renewable energies, and the price reduction of renewable energy sources have led to the need for solid-state transformers (SST). The latter is the power electronic transformer (PET), which exhibits high-frequency characteristics, bidirectional power flow, and electrical isolation. Thus, future smart grids could rely on the solid-state transformer (SST). It has several positive features for controlling the electrical energy flow and adding functions to the distribution grid as reactive power management by handling voltage drops. However, all these functionalities increase operational complexity.\u003c/p\u003e \u003cp\u003eAccording to different power conversion requirements, there are additional cascaded PET or SST topologies, such as AC-AC or AC-DC-DC-AC, for instance. Except for the first one, other topologies commonly include a DC-DC stage. This is used to achieve DC voltage conversion, power bi-directionality, and electrical isolation [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Such converters become attractive because their voltage gain ratio may be accommodated by the transformer. Among the bidirectional converters, dual active bridge voltage-fed converters (DAB) are helpful due to their performance and simplicity advantages.\u003c/p\u003e \u003cp\u003eThe DAB is often utilised at the intermediate stage of the electronic transformer because it provides good performance and a small current. A new bidirectional high voltage gain isolated soft-switched DC-DC converter (IBDC) using dual PWM may also be used [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The required high voltage gain may be attained by voltage and current doubler. A bidirectional boost converter modulates the rectified voltage to the desired level while transferring power.\u003c/p\u003e \u003cp\u003eThe virtual synchronous generator (VSG) is a strategy for handling the switches that makeup voltage source converters (VSCs), which is simple to implement, provides excellent performance, and becomes very attractive in modern power electronics applications [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Conventional VSG modeling comes from mimicking the induction of an electromotive force in a synchronous machine. Such signals play the role of modulating signals in a pulse width modulation (PWM) strategy. In this letter, an SST is controlled by a VSG. The analysed topology becomes an SST encompassing a three-phase rectifier, the DAB element, and a PWM inverter. The rectifier and the inverter are driven by VSG [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Notice that the scheme under analysis has three incoming or outgoing ports [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], which provides greater flexibility to a grid.\u003c/p\u003e \u003cp\u003eWith such an arrangement, it is possible to control the power flow from two ports to the third or from one to the other two; bi-directionality is essential in the scheme. Furthermore, the analysis demonstrates that the virtual synchronous generator can correctly handle such a topology.\u003c/p\u003e \u003cp\u003eThis letter focuses on using control based on the virtual synchronous machine concept (VSG) for handling power flows between different power systems in a microgrid. An SST is used to link such systems.\u003c/p\u003e \u003cp\u003eThe contribution of this letter lies in the fact that it proposes a way to make the distribution of electrical energy more flexible using an SST controlled by VSGs, achieving the desired objectives.\u003c/p\u003e"},{"header":"2. Vsg Control","content":"\u003cp\u003eHere we use a currently attractive approach when mentioning micro- and nano-grids, including the insertion of renewable technologies. There is usually an electronic inverter as a means of interconnection to the utility. One solution that can help stabilise such interconnections is to provide additional inertia virtually. Virtual inertia can positively support installations with distributed generators (DG)/renewable energy sources (RES) using short-term energy storage with a power electronics inverter/converter and an appropriate control mechanism. This concept can be described as a virtual synchronous generator (VSG) or synchronous virtual machine (VISMA).\u003c/p\u003e \u003cp\u003eThe concept of the virtual synchronous generator (VSG) is to mimic the behaviour of a synchronous machine by controlling a power electronic converter. Thus, VSGs are based on a descriptive model of a synchronous machine. Emulating inertia is a feature of all VSG control schemes, and the desired approximation in reproducing the electro-mechanical dynamics can vary. At the same time, other aspects, such as electrical transients, can be included or neglected.\u003c/p\u003e \u003cp\u003eIf the purpose of the VSG is to replicate the dynamic behaviour, a full-order model of the generator must be included. This includes a fifth-order electrical model with the representation of different windings and, in addition, a second-order mechanical model.\u003c/p\u003e \u003cp\u003eSeveral control schemes have been reported for the VSG, which is the interface between the synchronous generator models and the electronic converter, among them the one proposed in [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], which in the authors' opinion, represents a good compromise between accuracy and simplicity, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eIn this letter, a VSG model, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, is utilised to generate triggers for the power switches in the rectifier-inverter arrangements in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the interface to grids A, B and C.\u003c/p\u003e \u003cp\u003eIn this case, the application is made by defining two reference signals (\u003cem\u003ePset\u003c/em\u003e and \u003cem\u003eQset\u003c/em\u003e, active and reactive power) in the case of the inverters and (\u003cem\u003eQset\u003c/em\u003e and \u003cem\u003eVdc\u003c/em\u003e, reactive power and dc voltage) for the rectifier.\u003c/p\u003e "},{"header":"3. Active Bridge Behaviour Under Voltage Variations","content":"\u003cp\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows a programmable AC signal input. The signal's frequency changes from 60 Hz to 70 Hz and its amplitude varies between 500 V and 700 V. This signal tries to emulate the type of events that can occur in an unregulated wind turbine. Changes in its frequency and amplitude are magnitudes that occur regularly in systems of this type.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e displays the corresponding output. Note that this is to maintain a constant line-to-line voltage at 60 Hz. However, if the input signal drops below its nominal voltage, the DAB will not be able to maintain a continuous output signal. Concerning frequency, it does not matter if the frequency of the input source varies. This is due to the output connection of the dc-dc converter to the inverter stage.\u003c/p\u003e \u003cp\u003eThe dual active bridge transfers the most power with a 90\u0026deg; phase shift. However, a significant phase shift requires a high leakage inductance to transmit power. The use of high inductance results in increased currents on the primary and secondary sides of the transformer, which reduces the converter's efficiency. Table I summarises some electrical specifications of the dc-dc converter for this simulation.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable I.\u003c/b\u003e Electrical parameters of the dc-dc converter.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase shift\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.78 \u0026lt; \u0026Oslash; \u0026lt; 0.78 (rad)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal leakage inductance\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19.5 \u0026micro;H\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePMW switching frequency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100 kHz\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTurns Ratio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInput voltage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1000 V\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutput Voltage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e600 V\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePower Output\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 kW\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePeak 85%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe converter signals are controlled using the block diagram in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, where a difference between the reference voltage and the desired voltage is observed. This difference constitutes the error signal regulated by a PID that intervenes in the signals' phase angle. Similarly, the difference between the reference current and the output current is used to correct the signal by adjusting the phase angle of the pulses.\u003c/p\u003e \u003cp\u003eThe primary and secondary signals are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. It can be seen that the secondary signal is out of phase with the primary signal. Similarly, the leakage current of the high-frequency transformer is measured.\u003c/p\u003e \u003cp\u003eThe DAB allows the frequency to be kept stable, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003ea. After a short period of transient variation, the DAB returns to its nominal value of 60 Hz and remains there regardless of whether the frequency or input voltage changes. The specifications in Table I illustrate the construction of a dc-dc converter with 10 kW of output power and a phase angle of 45 degrees. Figure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eb depicts the output signals of the input power of the dc-dc converter (blue) and the converter's output (red). For resistive loads, the efficiency of the converter is between 80 and 85 percent.\u003c/p\u003e "},{"header":"4. Case Studies","content":"\u003cp\u003eThe case study is intended to demonstrate the enormous possibilities of flexibility in power supply that can be achieved with modern devices such as the electronic transformer controlled with a VSG scheme. It assumes an arrangement linking three grids, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. These can represent a utility, a generator, or a renewable energy source, for example.\u003c/p\u003e \u003cp\u003eThe simulated events described in the following demonstrate the benefits of this modern equipment. During the entire study time, network \u003cem\u003eC\u003c/em\u003e kept demanding 20 kW. Grid \u003cem\u003eB\u003c/em\u003e does not deliver or require energy during the interval t = [0, 2) s. Thus, meanwhile, \u003cem\u003eA\u003c/em\u003e supplies the demand of \u003cem\u003eC\u003c/em\u003e plus losses. At time t\u0026thinsp;=\u0026thinsp;2 s, grid \u003cem\u003eB\u003c/em\u003e demands 25 kW and continues until time t\u0026thinsp;=\u0026thinsp;4 s. During such an interval, grid \u003cem\u003eA\u003c/em\u003e is in charge of supplying all the energy required. Finally, at t\u0026thinsp;=\u0026thinsp;4 s, grid \u003cem\u003eB\u003c/em\u003e starts to provide 25 kW so that it is sufficient to satisfy the demand of 20 kW by \u003cem\u003eC\u003c/em\u003e, and the surplus is delivered to grid \u003cem\u003eA\u003c/em\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e(\u003cem\u003ea\u003c/em\u003e). Regarding reactive power management, the three VSG's controls set the reactive power reference at zero, Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e(\u003cem\u003eb\u003c/em\u003e). Figure\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e(c) first illustrates the rectifier's DC voltage behaviour. The second and third images are the voltages at the \u003cem\u003eB\u003c/em\u003e and \u003cem\u003eC\u003c/em\u003e terminals; note tolerable transients when changing conditions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDeveloping new magnetic materials that handle high flux densities and frequencies with lower losses is suitable for creating efficient SSTs. In addition, the advent of distributed generation and the development of intelligent microgrids encourage this type of technology.\u003c/p\u003e \u003cp\u003eDouble active bridge (DAB) converters are employed in the converter, using the leakage inductance transformer as the inductance. This reduces the volume since including a coil is not required, improving the system's efficiency. In DAB elements, phase shifting transfers power from one port to another.\u003c/p\u003e \u003cp\u003eAs can be seen in reference [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], in most of the known SST topologies, a PWM strategy is used to manage them. This results in reliability and simplicity. Aspects are highly sought after in complex topologies such as the subject of this letter. These aspects tie in very well with the VSG-type control chosen here. Especially maintaining a unity power factor can be advantageous for grid operation.\u003c/p\u003e \u003cp\u003eIn this type of controller, the active and reactive power values are used to compare their reference values. Finally, those will depend on the measured values of voltages and currents. Practical, robust, and fast sensors that perform their work almost instantaneously are now available, making this sensing stage very reliable.\u003c/p\u003e \u003cp\u003eFurthermore, the implementation of the VSG strategy is very affordable through cheap and reliable development boards and low-cost and fast FPGAs. Thus, the proposed control scheme can be implemented relatively simply and efficiently.\u003c/p\u003e \u003cp\u003eThe simulation results show that the proposed scheme can effectively handle power flows in a microgrid. Moreover, the VSG strategy is quite convenient when defining reference active and reactive power values for flexibility management in the network.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Frequency behaviour\u003c/h2\u003e \u003cp\u003eNote that in the system studied, two networks operate at 60 Hz, and a third operates at 50 Hz. This highlights the possibilities of this type of transformer. It is important to note that two systems operate at 60 Hz, while the third system operates at 50 Hz, thus highlighting the possibilities of this type of transformer. It is important to note that the main changes occur in network B (network C consumes energy, but in this study, it does not change its level of consumption). Thus, networks A and C show practically no noticeable variations in frequency, as shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e(\u003cem\u003ea\u003c/em\u003e) and 10(\u003cem\u003ec\u003c/em\u003e). This is not the case for network B, where the changes in demand are experienced, Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e(\u003cem\u003eb\u003c/em\u003e). Note that the frequency varies momentarily, but after a short time, it returns to its nominal state of 50 Hz. The rapidity at which the frequency returns depends on the controllers' parameters (which, in this case, have not been optimised), the capacitors' size, and other factors. This makes the electronic transformer attractive for this purpose, as it can achieve a constant frequency response.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Frequency fluctuations\u003c/h2\u003e \u003cp\u003eIn this section, network A undergoes ramped variations in frequency (0.25 Hz/s rise and fall). The aim is to verify the robustness of the device to this type of event by confirming what happens in networks B and C when these events occur.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e (increase in frequency in network A) and Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e (decrease in frequency in network A) show that, despite these variations in frequency, the behaviour of networks B and C is similar to that expected. That is to say that network B experiences transients in its frequency due to the change in demand and that network C keeps its frequency constant. This is a transformer's desirable feature, as it is expected that some of the networks may be connected to wind generation, for example.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e4.3. Reactive power handling\u003c/h2\u003e \u003cp\u003eThis section studies the behaviour of reactive power in the different ports of the device. It should be noted that in all three networks, the reactive power delivery has been set at 0 VARS. Thus, Figs.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003e show the reactive power variations in response to changes in the voltage of network A, including the variations in the demand of network B, already described. The latter is ramped with a 0.025 V/s ratio. Notice how the voltages in networks B and C vary and the reactive power in the three ports. Note that the reactive power exhibits a higher sensitivity than that associated with the active power, although the control tries to keep it at 0 VARS average. Voltage variations in port A have practically no impact on the corresponding voltage in ports B and C. The effect of demand variations in network B on the reagents of the three ports is more noticeable.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThe solid-state transformer is a grid element that provides advantageous flexibility to the operation, mainly due to its bidirectional capacity that uses converters such as the dual active bridge that assumes an essential role in the device. The bidirectional power flow characteristic is a determining factor in distributed generation schemes. The networks may be operated by modifying the flow direction, depending on various factors, such as the timetable and energy availability, for instance.\u003c/p\u003e \u003cp\u003eActive and reactive power flow controllability may be achieved by employing a virtual synchronous generator strategy, which has proven in this and many other applications to have attractive characteristics for managing DC-AC converters or vice versa, mainly in terms of its ease of implementation and appropriate performance to achieve the specified reference values.\u003c/p\u003e \u003cp\u003eAs verified, the device can maintain voltage and frequency values around its nominal specifications, despite slow variations of such signals at a port, making it very attractive for applications with power injections at different points in the network.\u003c/p\u003e \u003cp\u003eFor these reasons, this paper proposes the joint use of both strategies to coordinate the flows in a microgrid and thus provide operational flexibility.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ethe author has no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ethe work was carried out with the support of the Consejo Nacional de Ciencia y Tecnolog\u0026iacute;a -M\u0026eacute;xico, under the project FSE-2013-05-246949.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIf you are interested in the database used, please contact the author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eM. A. Hannan et al., \u0026quot;State of the Art of Solid-State Transformers: Advanced Topologies, Implementation Issues, Recent Progress and Improvements,\u0026quot; in IEEE Access, vol. 8, pp. 19113-19132, 2020, doi: 10.1109/ACCESS.2020.2967345.\u003c/li\u003e\n \u003cli\u003eQ.-C. Zhong, Synchronverter Based Generation, in Power Electronics-Enabled Autonomous Power Systems: Next Generation Smart Grids , Wiley-IEEE Press, 2020.\u003c/li\u003e\n \u003cli\u003eJ. Posada Contreras, J. M. Ramirez, \u0026quot;Multi-Fed Power Electronic Transformer for Use in Modern Distribution Systems\u0026quot;. IEEE Transactions on Smart Grid, Vol. 5, No. 3, May 2014, pp. 1532-1541.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Power electronics, Power electronic transformer, Solid-state transformer, Synchronverter, Virtual synchronous generator","lastPublishedDoi":"10.21203/rs.3.rs-2592578/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2592578/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA solid-state transformer controlled by a virtual synchronous generator is presented as an element capable of increasing the flexibility of electrical power distribution in a modern grid. With the advent of microgrids, the choice of strategies and devices capable of giving them flexibility has been of paramount importance. Emphasis has been shown on the transformer characteristics to regulate the frequency and voltage at its output terminals. This is very suitable for driving a wind turbine. Results are presented that demonstrate the versatility of such features working together.\u003c/p\u003e","manuscriptTitle":"Microgrid's regulation using a multiport SST","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-02-20 15:55:49","doi":"10.21203/rs.3.rs-2592578/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"860a9852-96b6-496d-9d79-7d4ec7a31b6c","owner":[],"postedDate":"February 20th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-07-09T06:44:21+00:00","versionOfRecord":[],"versionCreatedAt":"2023-02-20 15:55:49","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2592578","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2592578","identity":"rs-2592578","version":["v1"]},"buildId":"ehx78VzkSd0WSzXnipQa-","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}