J.A. Latorre Correa
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The electrification of shipboard power systems carries an increasing variety in power sources, energy storage systems, and power converters. DC distribution is gaining relevance due to efficiency increase, space savings, and high controllability. The dominant primary control method voltage droop control, which offers easily implementable and scalable power sharing and voltage stabilization. However, compared to terrestrial microgrids, shipboard power systems have low line impedances and highly fluctuating loads. Most primary loads are power-controlled, introducing a non-linearity that leads to a weak damping and unstable operation points. To handle this non-linearity, this study proposes an energy-based control approach as an alternative to the voltage-based scheme. The controller is further extended by integral feedback loop to achieve fast voltage restoration. A low-bandwidth communication is leveraged for an adaptive power sharing control that facilitates an efficient allocation of the load among parallel units under varying conditions. The proposed control structure is deployed on an I/O board embedded in a hardware-in-the-loop testbed. It is shown that the energy-based controller operates stably and achieves a reduced voltage deviation from the nominal voltage in various load conditions compared to the conventional voltage-based method.
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The electrification of shipboard power systems carries an increasing variety in power sources, energy storage systems, and power converters. DC distribution is gaining relevance due to efficiency increase, space savings, and high controllability. The dominant primary control method voltage droop control, which offers easily implementable and scalable power sharing and voltage stabilization. However, compared to terrestrial microgrids, shipboard power systems have low line impedances and highly fluctuating loads. Most primary loads are power-controlled, introducing a non-linearity that leads to a weak damping and unstable operation points. To handle this non-linearity, this study proposes an energy-based control approach as an alternative to the voltage-based scheme. The controller is further extended by integral feedback loop to achieve fast voltage restoration. A low-bandwidth communication is leveraged for an adaptive power sharing control that facilitates an efficient allocation of the load among parallel units under varying conditions. The proposed control structure is deployed on an I/O board embedded in a hardware-in-the-loop testbed. It is shown that the energy-based controller operates stably and achieves a reduced voltage deviation from the nominal voltage in various load conditions compared to the conventional voltage-based method.
The development of DC protection systems is an enabler of widespread adoption of DC microgrids. This paper introduces a three-level gate driver that provides the latching current limiter functionality in a solid-state circuit breaker with unidirectional protection. The proposed gate driver combines the output port description of a well-known, enabled gate driver with a soft turn-off network. The corresponding circuit can be adapted to well-established SSCBs, requiring few modifications which could allow for quick development. The concept, simulation, implementation and experimental validation of the gate driver are in the scope of the paper. The gate driver is implemented and tested in a solid-state circuit breaker prototype, showing the potential to develop further DC protection devices.
...
The development of DC protection systems is an enabler of widespread adoption of DC microgrids. This paper introduces a three-level gate driver that provides the latching current limiter functionality in a solid-state circuit breaker with unidirectional protection. The proposed gate driver combines the output port description of a well-known, enabled gate driver with a soft turn-off network. The corresponding circuit can be adapted to well-established SSCBs, requiring few modifications which could allow for quick development. The concept, simulation, implementation and experimental validation of the gate driver are in the scope of the paper. The gate driver is implemented and tested in a solid-state circuit breaker prototype, showing the potential to develop further DC protection devices.
Protection of Shipboard DC systems
From capacitors to ultrafast devices
The development of shipboard DC power systems promises significant operational and economic benefits but faces major challenges in primary distribution, protection, and power scalability. As DC technology continues to mature, many aspects of shipboard implementation remain insufficiently defined to guarantee both safety and efficiency. Current regulatory standards are incomplete, and protection strategies often rely on outdated or inadequate frameworks. Unipolar and bipolar bus architectures each offer application-specific advantages, and the strategic placement of power electronics opens new possibilities for centralized and distributed switchboard designs. However, protection architectures still face limitations: breaker-based approaches rely on slow fuses, mechanical circuit breakers, or emerging solid-state circuit breakers, while power electronics–based protection, embedding protective functions within converters, remains underdeveloped. Furthermore, the low production rate of vessels and the varied power demands across applications often force designers to employ commercial off-the-shelf converters, raising challenges in modular topologies, scalability, and overall protection strategy.
This research addresses protection challenges through a multi-stage investigation into shipboard DC systems and power electronics for DC protection. First, a
use case–based categorization of short-circuit events in primary DC systems is proposed. A detailed fault inventory is compiled using a reference 5 MW superyacht model, providing simulation-based short-circuit data for diverse operational scenarios. The study contributes: (1) a comprehensive short-circuit inventory, (2) a qualitative fault categorization, and (3) design recommendations for power converters in shipboard DC systems. This work emphasizes that systematic fault classification is critical to understanding the impact of different short circuits and to guiding both protective device design and regulatory evolution.
In parallel, the thesis advances the state of the art in DC fault protection hardware. A high-speed solid-state circuit breaker (SSCB) is developed, integrating
a latching current limiter to prevent unnecessary tripping during transient overcurrents. Supported by a custom gate driver and controller, the SSCB prototype
achieves a clearing time of approximately 200 ns, substantially reducing system stress during faults. Both SPICE simulations and experimental tests confirm its
capability to properly operate under diverse fault conditions while requiring low complexity upgrades.
Finally, a proof-of-concept DC–DC converter with embedded protection is demonstrated. The proposed protection module, based on the electronic capacitor concept, is integrated into a 10 kW bidirectional LLC converter. Placed in series with the DC-link capacitor, the module significantly reduces processed power and conduction losses compared to conventional series-breaker configurations. Experimental validation confirms that the approach is compatible with fuse-based selectivity strategies while offering rapid fault isolation and reduced design complexity.
Collectively, this thesis provides a comprehensive framework, from system-level fault categorization to device-level protection design, supporting the safe and scalable adoption of shipboard DC systems. The proposed solutions and prototypes contribute to addressing essential protection challenges, favoring the widespread adoption of DC systems in various applications, by offering more efficient, compact, and safe DC systems, which ultimately play an important role in the transition of energy for transportation in general. ...
This research addresses protection challenges through a multi-stage investigation into shipboard DC systems and power electronics for DC protection. First, a
use case–based categorization of short-circuit events in primary DC systems is proposed. A detailed fault inventory is compiled using a reference 5 MW superyacht model, providing simulation-based short-circuit data for diverse operational scenarios. The study contributes: (1) a comprehensive short-circuit inventory, (2) a qualitative fault categorization, and (3) design recommendations for power converters in shipboard DC systems. This work emphasizes that systematic fault classification is critical to understanding the impact of different short circuits and to guiding both protective device design and regulatory evolution.
In parallel, the thesis advances the state of the art in DC fault protection hardware. A high-speed solid-state circuit breaker (SSCB) is developed, integrating
a latching current limiter to prevent unnecessary tripping during transient overcurrents. Supported by a custom gate driver and controller, the SSCB prototype
achieves a clearing time of approximately 200 ns, substantially reducing system stress during faults. Both SPICE simulations and experimental tests confirm its
capability to properly operate under diverse fault conditions while requiring low complexity upgrades.
Finally, a proof-of-concept DC–DC converter with embedded protection is demonstrated. The proposed protection module, based on the electronic capacitor concept, is integrated into a 10 kW bidirectional LLC converter. Placed in series with the DC-link capacitor, the module significantly reduces processed power and conduction losses compared to conventional series-breaker configurations. Experimental validation confirms that the approach is compatible with fuse-based selectivity strategies while offering rapid fault isolation and reduced design complexity.
Collectively, this thesis provides a comprehensive framework, from system-level fault categorization to device-level protection design, supporting the safe and scalable adoption of shipboard DC systems. The proposed solutions and prototypes contribute to addressing essential protection challenges, favoring the widespread adoption of DC systems in various applications, by offering more efficient, compact, and safe DC systems, which ultimately play an important role in the transition of energy for transportation in general. ...
The development of shipboard DC power systems promises significant operational and economic benefits but faces major challenges in primary distribution, protection, and power scalability. As DC technology continues to mature, many aspects of shipboard implementation remain insufficiently defined to guarantee both safety and efficiency. Current regulatory standards are incomplete, and protection strategies often rely on outdated or inadequate frameworks. Unipolar and bipolar bus architectures each offer application-specific advantages, and the strategic placement of power electronics opens new possibilities for centralized and distributed switchboard designs. However, protection architectures still face limitations: breaker-based approaches rely on slow fuses, mechanical circuit breakers, or emerging solid-state circuit breakers, while power electronics–based protection, embedding protective functions within converters, remains underdeveloped. Furthermore, the low production rate of vessels and the varied power demands across applications often force designers to employ commercial off-the-shelf converters, raising challenges in modular topologies, scalability, and overall protection strategy.
This research addresses protection challenges through a multi-stage investigation into shipboard DC systems and power electronics for DC protection. First, a
use case–based categorization of short-circuit events in primary DC systems is proposed. A detailed fault inventory is compiled using a reference 5 MW superyacht model, providing simulation-based short-circuit data for diverse operational scenarios. The study contributes: (1) a comprehensive short-circuit inventory, (2) a qualitative fault categorization, and (3) design recommendations for power converters in shipboard DC systems. This work emphasizes that systematic fault classification is critical to understanding the impact of different short circuits and to guiding both protective device design and regulatory evolution.
In parallel, the thesis advances the state of the art in DC fault protection hardware. A high-speed solid-state circuit breaker (SSCB) is developed, integrating
a latching current limiter to prevent unnecessary tripping during transient overcurrents. Supported by a custom gate driver and controller, the SSCB prototype
achieves a clearing time of approximately 200 ns, substantially reducing system stress during faults. Both SPICE simulations and experimental tests confirm its
capability to properly operate under diverse fault conditions while requiring low complexity upgrades.
Finally, a proof-of-concept DC–DC converter with embedded protection is demonstrated. The proposed protection module, based on the electronic capacitor concept, is integrated into a 10 kW bidirectional LLC converter. Placed in series with the DC-link capacitor, the module significantly reduces processed power and conduction losses compared to conventional series-breaker configurations. Experimental validation confirms that the approach is compatible with fuse-based selectivity strategies while offering rapid fault isolation and reduced design complexity.
Collectively, this thesis provides a comprehensive framework, from system-level fault categorization to device-level protection design, supporting the safe and scalable adoption of shipboard DC systems. The proposed solutions and prototypes contribute to addressing essential protection challenges, favoring the widespread adoption of DC systems in various applications, by offering more efficient, compact, and safe DC systems, which ultimately play an important role in the transition of energy for transportation in general.
This research addresses protection challenges through a multi-stage investigation into shipboard DC systems and power electronics for DC protection. First, a
use case–based categorization of short-circuit events in primary DC systems is proposed. A detailed fault inventory is compiled using a reference 5 MW superyacht model, providing simulation-based short-circuit data for diverse operational scenarios. The study contributes: (1) a comprehensive short-circuit inventory, (2) a qualitative fault categorization, and (3) design recommendations for power converters in shipboard DC systems. This work emphasizes that systematic fault classification is critical to understanding the impact of different short circuits and to guiding both protective device design and regulatory evolution.
In parallel, the thesis advances the state of the art in DC fault protection hardware. A high-speed solid-state circuit breaker (SSCB) is developed, integrating
a latching current limiter to prevent unnecessary tripping during transient overcurrents. Supported by a custom gate driver and controller, the SSCB prototype
achieves a clearing time of approximately 200 ns, substantially reducing system stress during faults. Both SPICE simulations and experimental tests confirm its
capability to properly operate under diverse fault conditions while requiring low complexity upgrades.
Finally, a proof-of-concept DC–DC converter with embedded protection is demonstrated. The proposed protection module, based on the electronic capacitor concept, is integrated into a 10 kW bidirectional LLC converter. Placed in series with the DC-link capacitor, the module significantly reduces processed power and conduction losses compared to conventional series-breaker configurations. Experimental validation confirms that the approach is compatible with fuse-based selectivity strategies while offering rapid fault isolation and reduced design complexity.
Collectively, this thesis provides a comprehensive framework, from system-level fault categorization to device-level protection design, supporting the safe and scalable adoption of shipboard DC systems. The proposed solutions and prototypes contribute to addressing essential protection challenges, favoring the widespread adoption of DC systems in various applications, by offering more efficient, compact, and safe DC systems, which ultimately play an important role in the transition of energy for transportation in general.
Journal article
(2025)
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Alejandro Latorre, Thiago Batista Soeiro, Anand Krishnamurthy Iyer, Rinze Geertsma, H. Polinder
The advancement of DC systems, especially in transportation applications, hinges on the development of effective protection mechanisms. Robust protection systems are crucial for enabling the widespread adoption of DC technologies in important transport modes, offering both operational and economic benefits. This paper introduces a high-speed solid-state circuit breaker designed for enhancing the protection of general DC systems. The upgraded breaker integrates the functionality of a latching current limiter, designed to minimize modifications to existing technologies. A custom gate driver and controller are developed and experimentally validated to support the circuit breaker. A scaled solid-state circuit breaker prototype is tested under various operational conditions to evaluate its performance. The breaker's behavior is simulated in SPICE to guide the experimental validation on a referential DC system. The results demonstrate high performance, with a clearing time close to 200ns, effectively reducing system stress during short circuits. The current limiter functionality prevents unnecessary tripping during temporary overcurrents, keeping the current within safe parameters. The innovative gate driver simplifies the implementation of the latching current limiter, offering a practical and scalable solution. This work represents a significant step forward in DC protection technology, promoting the adoption of DC systems in transportation applications and beyond, by addressing critical protection challenges.
...
The advancement of DC systems, especially in transportation applications, hinges on the development of effective protection mechanisms. Robust protection systems are crucial for enabling the widespread adoption of DC technologies in important transport modes, offering both operational and economic benefits. This paper introduces a high-speed solid-state circuit breaker designed for enhancing the protection of general DC systems. The upgraded breaker integrates the functionality of a latching current limiter, designed to minimize modifications to existing technologies. A custom gate driver and controller are developed and experimentally validated to support the circuit breaker. A scaled solid-state circuit breaker prototype is tested under various operational conditions to evaluate its performance. The breaker's behavior is simulated in SPICE to guide the experimental validation on a referential DC system. The results demonstrate high performance, with a clearing time close to 200ns, effectively reducing system stress during short circuits. The current limiter functionality prevents unnecessary tripping during temporary overcurrents, keeping the current within safe parameters. The innovative gate driver simplifies the implementation of the latching current limiter, offering a practical and scalable solution. This work represents a significant step forward in DC protection technology, promoting the adoption of DC systems in transportation applications and beyond, by addressing critical protection challenges.
This paper proposes an integrated gate driver featuring soft turn-off and current limiting for a solid-state circuit breaker in primary shipboard DC systems. The added functionalities allow solid-state circuit breakers to mitigate part of the voltage resonances caused by a hard turn-off, and to reduce unnecessary tripping during overloading events. The proposed design is based on well-known DC protection strategies, which are enhanced by the custom gate driver, simulated in SPICE software. The paper shows that the proposed strategy effectively attenuates the adverse effects of the hard turn-off present in popular off-the-shelf devices, while effectively breaking the fault current. The low propagation delay of the selected components facilitates the rapid break of the current, reaching approximately 69A peak. In addition, the latch current limiter prevents the feeder from overloading, creating a voltage drop of 51% for tens of nanoseconds. The results are promising in motivating future prototyping of the design in an attempt to accelerate the acceptance of shipboard DC systems.
...
This paper proposes an integrated gate driver featuring soft turn-off and current limiting for a solid-state circuit breaker in primary shipboard DC systems. The added functionalities allow solid-state circuit breakers to mitigate part of the voltage resonances caused by a hard turn-off, and to reduce unnecessary tripping during overloading events. The proposed design is based on well-known DC protection strategies, which are enhanced by the custom gate driver, simulated in SPICE software. The paper shows that the proposed strategy effectively attenuates the adverse effects of the hard turn-off present in popular off-the-shelf devices, while effectively breaking the fault current. The low propagation delay of the selected components facilitates the rapid break of the current, reaching approximately 69A peak. In addition, the latch current limiter prevents the feeder from overloading, creating a voltage drop of 51% for tens of nanoseconds. The results are promising in motivating future prototyping of the design in an attempt to accelerate the acceptance of shipboard DC systems.
Journal article
(2024)
-
Alejandro Latorre, Thiago Batista Soeiro, Xinqian Fan, Rinze Geertsma, Marjan Popov, Henk Polinder
The protection of DC systems in mobility applications, such as land transport, aircraft, and shipping, presents significant challenges due to the need for high power density equipment in confined spaces. This paper focuses on DC systems on board ships, for which diverse applications require different power levels, architectures, and protection strategies. Existing protection frameworks and regulations are often inadequate or outdated for the field, leading to certification issues and insufficient fault analysis. This research proposes a use case-based categorization of short circuit currents for primary systems. A reference scenario is created using a simulation model of a 5 MW system in a superyacht to provide a short circuit inventory. The study proposes three contributions. A comprehensive fault inventory, a qualitative categorization, and relevant recommendations for power converter design. The research highlights the importance of fault categorization in understanding the impact of various short circuits on shipboard DC systems. The study emphasizes the importance of the evolution of materials and power converters in developing efficient protection technologies for ships. This work addresses some fundamental gaps in shipboard DC systems, providing a foundation for improved protection strategies and regulations, ultimately contributing to the advancement of protection of shipboard DC systems.
...
The protection of DC systems in mobility applications, such as land transport, aircraft, and shipping, presents significant challenges due to the need for high power density equipment in confined spaces. This paper focuses on DC systems on board ships, for which diverse applications require different power levels, architectures, and protection strategies. Existing protection frameworks and regulations are often inadequate or outdated for the field, leading to certification issues and insufficient fault analysis. This research proposes a use case-based categorization of short circuit currents for primary systems. A reference scenario is created using a simulation model of a 5 MW system in a superyacht to provide a short circuit inventory. The study proposes three contributions. A comprehensive fault inventory, a qualitative categorization, and relevant recommendations for power converter design. The research highlights the importance of fault categorization in understanding the impact of various short circuits on shipboard DC systems. The study emphasizes the importance of the evolution of materials and power converters in developing efficient protection technologies for ships. This work addresses some fundamental gaps in shipboard DC systems, providing a foundation for improved protection strategies and regulations, ultimately contributing to the advancement of protection of shipboard DC systems.
Shipboard DC systems, a Critical Overview
Challenges in Primary Distribution, Power Electronics-based Protection, and Power Scalability
Journal article
(2023)
-
Alejandro Latorre, Thiago Batista Soeiro, Rinze Geertsma, Andrea Coraddu, Henk Polinder
This article gives an overview of challenges in primary distribution, protections, and power scalability for shipboard dc systems. Given that dc technology is in development, several aspects of shipboard systems have not yet been sufficiently devised to ensure the protection and efficiency demanded. Several issues in dc systems arise from the lack of complete relevant standardization from different regulation bodies. Unipolar and bipolar bus architectures have application-specific advantages that are discussed and compared. The placement of power electronics in dc systems creates opportunities for switchboard design, and this article compares the centralized and distributed approaches. Likewise, protection architectures for shipboard dc systems have challenges. Breaker-based protection utilizes slow fuses, mechanical circuit breakers, and solid-state circuit breakers. In addition, power-electronics-based protection embeds the protective circuit in the power converters, but its development lags. This article compares the state-of-the-art technologies, reviewing their main features. Finally, the power requirement of various applications and the low production rate of vessels force the designers to utilize commercial off-the-shelf converters to scale up power. The misuse of such converters, the modular topologies, and power electronics building blocks are exposed highlighting challenges and opportunities toward the mass adoption of dc systems onboard maritime vessels.
...
This article gives an overview of challenges in primary distribution, protections, and power scalability for shipboard dc systems. Given that dc technology is in development, several aspects of shipboard systems have not yet been sufficiently devised to ensure the protection and efficiency demanded. Several issues in dc systems arise from the lack of complete relevant standardization from different regulation bodies. Unipolar and bipolar bus architectures have application-specific advantages that are discussed and compared. The placement of power electronics in dc systems creates opportunities for switchboard design, and this article compares the centralized and distributed approaches. Likewise, protection architectures for shipboard dc systems have challenges. Breaker-based protection utilizes slow fuses, mechanical circuit breakers, and solid-state circuit breakers. In addition, power-electronics-based protection embeds the protective circuit in the power converters, but its development lags. This article compares the state-of-the-art technologies, reviewing their main features. Finally, the power requirement of various applications and the low production rate of vessels force the designers to utilize commercial off-the-shelf converters to scale up power. The misuse of such converters, the modular topologies, and power electronics building blocks are exposed highlighting challenges and opportunities toward the mass adoption of dc systems onboard maritime vessels.