Overvoltage Elimination via Distributed Backstepping-Controlled Converters in Near-Zero-Energy Buildings Under Excess Solar Power to Improve Distribution Network Reliability J. Dionísio Barros, Luis Rocha, A. Moisés, J. Fernando Silva Energies, 2026 This work uses battery-coupled power electronic converter systems and distributed backstepping controllers to improve the reliability of electrical distribution networks. The motivation is to prevent blackouts such as the 28 April 2025 outage in Spain, Portugal, and the south of France. It is now accepted that a rapid rise in solar power injections caused AC overvoltage above grid code limits, triggering photovoltaic (PV) park disconnections as overvoltage self-protection. This case study considers near-Zero-Energy Buildings (nZEBs) connected to the Madeira Island isolated microgrid, where PV power installation is increasing excessively. The main university facility will be upgraded as an nZEB, using roughly 3000 m2 of unshaded rooftops plus coverable parking areas to install PV panels. Optimizing the profits/energy cost ratio, a PV power system of around 560 kW can be planned, and the Battery Storage System (BSS) energy capacity can be estimated. The BSS is connected to the university nZEB via backstepping-controlled multilevel converters to manage PV and BSS, enabling the building to contribute to voltage and frequency regulation. Distributed multilevel converters inject renewable energy into the medium-voltage network, regulating active and reactive power to prevent overvoltages shutting down the PV inverters. This removes sustained overvoltage and maximizes PV penetration while augmenting AC grid reliability and resilience. When there is excess solar power and reactive power is insufficient to reduce voltage, controllers slightly curtail PV active power to eliminate overvoltage, maintaining operation with minimal revenue loss while preventing long interruptions, thereby improving grid reliability and power quality.
Interleaved Quadratic Boost DC-DC Converter with Extended Voltage Gain and Reduced Switch Voltage Stress for Photovoltaic Applications Daniel Ferreira, Armando Cordeiro, Paulo Gambôa, Luis Rocha, Filipe Barata, et al. Open Research Europe, 2025 Background DC-DC power converters are essential devices in the modern world, playing a crucial role in managing the power supply from different power sources converting and adapting voltage levels. These power converters are fundamental to numerous applications, from charging your mobile phone to powering different types of machinery. Lately, due to climate change problems and the floating nature of most renewable power sources, they are essential to a carbon-free world and zero emissions target. Methods Our investigation method was based on an initial theoretical approach using mathematical equations to describe the operation of the electrical circuit and evaluate the performance compared to other topologies, followed by the validation through some computational simulations using MATLAB/SIMULINK software. Next, the operation of the proposed converter was also confirmed by several experimental tests using a laboratory prototype developed exclusively for these tests. Results Based on the achieved results, an efficiency analysis was performed showing that in addition to high-voltage gain, from the range of six to eight times the input voltage, the converter maintains a very high efficiency, around 95% to 96% up to a duty cycle of 0.50, where a voltage gain of 5.82 is achieved in a real setup Also, the optimal operating point was identified, based on the duty cycle, where the converter operates at maximum efficiency. In PLECS® simulation environment, dynamic tests under PI output voltage control revealed fast transient response and good voltage regulation, while MPPT PV simulations demonstrated effective maximum power extraction and tracking under variable irradiance and temperature conditions. Conclusions In conclusion, it is possible to claim that the proposed converter presents a stable and efficient operation and has a very high potential for applications that require high-voltage gain, such as photovoltaic solar systems or even electrical vehicles or energy storage systems. Other relevant aspect is the reduced value of capacitors, due to the interleaved operation, leading to reduced stress over capacitors and distributed voltage over them.
Virtual Generator to Replace Backup Diesel GenSets Using Backstepping Controlled NPC Multilevel Converter in Islanded Microgrids with Renewable Energy Sources J. Dionísio Barros, J. Fernando A. Silva, Luis Rocha Electronics Switzerland, 2024 This work presents an islanded microgrid energy system that uses backstepping control applied to neutral point clamped (NPC) multilevel converters coupled with batteries to behave as virtual generators, able to absorb surplus renewable energy, therefore increasing the penetration of renewable energy sources. Additionally, on a charged battery the virtual generator allows turning-off the backup diesel generator set (GenSet). Aside from improving energy efficiency, the battery-connected multilevel converter aims to regulate frequency, improves power quality, and keeps the microgrid operational in the event of a GenSet failure. The backstepping controlled NPC multilevel converter emulates a virtual generator injecting power to perform as the primary and secondary microgrid frequency controller. Additionally, AC voltage control is implemented, which enables running the islanded microgrid only with multilevel converters, supplied by the battery while integrating solar and wind energy sources. Energy demand and renewable energy forecasts are used to manage the battery state-of-charge. Simulation results, obtained from switched and phasor models show that energy storage and the backstepping frequency control enables the compensation of power fluctuations from renewable energy sources. Furthermore, in the event of the main GenSet failure, the controlled virtual generator keeps the microgrid running for a few minutes, until another GenSet is ready to supply the microgrid. Therefore, the microgrid integration of the battery-connected multilevel converter results in a significant boost in energy efficiency by allowing the disconnection of the backup GenSet.
Isolated Quasi-Switched Boost Integrated T-Type DC-DC Converter for DC Microgrid Daniel Ferreira, Armando Cordeiro, Luis Rocha, Enrique Romero-Cadaval, Carlos Roncero-Clemente, et al. 13th International Conference on Renewable Energy Research and Applications Icrera 2024, 2024 Over the last few years, there has been a high demand for new or improved isolated DC-DC to fulfill requirements of applications related with RES. In this context, this paper introduces a new isolated DC-DC converter, for use in renewable energy applications. The topology proposed contains an Active quasi-switched Boost Three-Level T-type DC-DC converter with continuous input current at the converter input side, connected to a high-frequency step-up isolation transformer, and a voltage doubler rectifier (VDR) on the output side. The steady-state analysis of the proposed converter is presented and discussed. Simulation results are presented to verify the theory and performance of the converter.
Seven-Level Transformerless Inverter with a Double Boost Controlled Cell Daniel Ferreira, Armando Cordeiro, Luís Rocha, J. Fernando Silva, Enrique Romero-Cadaval, et al. Proceedings of the 2024 21st International Conference on Mechatronics Mechatronika Me 2024, 2024 This paper presents a new high-voltage gain single-phase seven-level Boost inverter topology with reduced harmonic distortion. The proposed solution introduces a transformerless multilevel voltage source inverter with reduced number of passive and active power components using only a single input DC power source. The maximum voltage gain is three times higher than the input power source. The circuit is composed by a double boost controlled cell using a single power device where both inductors suppress the capacitors current charge spikes. The proposed topology is verified under different conditions, and the some simulation and experimental results are presented, considering a 300 W laboratory prototype model.
Backstepping Control of NPC Multilevel Converter Interfacing AC and DC Microgrids J. Dionísio Barros, Luis Rocha, J. Fernando Silva Energies, 2023 This work introduces modified backstepping methods to design controllers for neutral point clamped (NPC) converters interfacing a DC/AC microgrid. The modified backstepping controllers are derived from a proper converter model, represented in dq coordinates, and are designed to regulate the DC voltage and to balance the two NPC converter DC capacitor voltages through a DC offset in the sinusoidal pulse width modulation (SPWM) carriers. The averaged and separated dynamics backstepping controllers also enforce nearly sinusoidal AC currents at a given power factor. The two proposed NPC converter controllers are evaluated through MATLAB/Simulink simulations and experimental implementation using a laboratory prototype. Simulations and experimental results show that the two modified backstepping controllers regulate the microgrid DC voltage in steady state and in transient operation, even with load disturbances or DC voltage reference changes, while enforcing nearly AC sinusoidal currents at a given power factor or injected reactive power. The modified backstepping-controlled NPC converter is bidirectional, converting energy from DC renewable energy sources or storage systems to AC or charging storage systems from AC. The results also highlight the effective balancing of the NPC DC capacitor voltages.
Backstepping predictive control of hybrid microgrids interconnected by neutral point clamped converters J. Dionísio Barros, Luis Rocha, J. Fernando Silva Electronics Switzerland, 2021 In this work, DC and AC parts of hybrid microgrids are interconnected by a neutral point clamped—NPC converter controlled using a new backstepping predictive (BP) method. The NPC converter is controlled to operate in the DC microgrid voltage control mode or in the AC microgrid power control mode. The novel backstepping predictive controller is designed using the dq state space dynamic model of the NPC converter connected to the hybrid microgrid. The designed BP controller regulates the DC voltage or AC injected power, balances the capacitor voltages, controls the AC currents, and enforces the near unity power factor. Simulation (MATLAB/Simulink) and experimental (laboratory prototype) results show that the converter can regulate the DC voltage in the DC microgrid interconnection point, by adjusting the AC power conversion to compensate variations on the loads or on the distributed renewable energy sources in the DC microgrid. AC currents are sinusoidal with low harmonic distortion. The obtained BP controller is faster at balancing capacitor voltages than PWM (pulse width modulation) control with carrier offset. The fast AC power response allows the converter to be used as a primary frequency regulator of the AC microgrid. This research is appropriate for power and voltage control in hybrid microgrids with renewable energy.
Marx Multilevel Bipolar Modulator Dynamic Models for Load Transient Analysis L. Lamy Rocha, J. Fernando Silva, L. M. Redondo IEEE Transactions on Plasma Science, 2017 This paper presents generalized dynamic models for Marx derived multilevel half-bridge bipolar modulators. This high-voltage topology uses modular Marx multilevel converter diode (<inline-formula> <tex-math notation="LaTeX">$\\text{M}^{\\mathrm {{3}}}$ </tex-math></inline-formula>CD) cells to generate positive and negative (bipolar) pulses or unipolar (positive or negative voltage pulses). The developed models are tested in transient studies of pulse voltages and currents in the load. Simulation and experimental results are presented and compared.
Optimized solid-state bipolar Marx modulador with resonant type droop compensation H. Canacsinh, F. A. Silva, L. M. Redondo, L. Rocha, V. Silva, et al. IEEE International Pulsed Power Conference, 2017 In this paper a voltage droop compensation based on a resonant circuit is proposed for the optimized solid-state bipolar Marx modulator. Keeping the modularity characteristics and the circuit topology, one auxiliary resonant stage was added to the existing Marx stages. The compensation concept consists of adding the auxiliary voltage to the output positive or negative pulse for voltage droop compensation. Simulation results are presented for five stages Marx circuit, 10% voltage droop, using 800 V per stage, 100 ps pulse duration at 50Hz frequency.
Interleaved Quadratic Boost DC-DC Converter with Extended Voltage Gain and Reduced Switch Voltage Stress for Photovoltaic Applications D Ferreira, A Cordeiro, P Gambôa, L Rocha, F Barata, JF Silva, JF Martins, ... Open Research Europe 5, 55 , 2025 2025 Citations: 5
Seven-Level Transformerless Inverter with a Double Boost Controlled Cell D Ferreira, A Cordeiro, L Rocha, JF Silva, E Romero-Cadaval, ... 2024 21st International Conference on Mechatronics-Mechatronika (ME), 1-6 , 2024 2024
Virtual Generator to Replace Backup Diesel GenSets Using Backstepping Controlled NPC Multilevel Converter in Islanded Microgrids with Renewable Energy Sources JD Barros, JFA Silva, L Rocha Electronics 13 (22), 4511 , 2024 2024 Citations: 3
Isolated quasi-switched boost integrated T-type DC-DC converter for DC microgrid D Ferreira, A Cordeiro, L Rocha, E Romero-Cadaval, ... 2024 13th International Conference on Renewable Energy Research and … , 2024 2024 Citations: 3
New backstepping controllers with enhanced stability for neutral point clamped converters interfacing photovoltaics and AC microgrids JD Barros, JFA Silva, L Rocha International Journal of Electrical Power & Energy Systems 153, 109332 , 2023 2023 Citations: 10
Backstepping control of NPC multilevel converter interfacing AC and DC microgrids JD Barros, L Rocha, JF Silva Energies 16 (14), 5515 , 2023 2023 Citations: 9
Backstepping predictive control of hybrid microgrids interconnected by neutral point clamped converters JD Barros, L Rocha, JF Silva Electronics 10 (10), 1210 , 2021 2021 Citations: 9
Novel design of the converter for an active UPS application based on marx modulator concept with supercapacitors C Pestana, H Canacsinh, M Chaves, P Gamboa, A Cordeiro, R Luís, ... Doctoral Conference on Computing, Electrical and Industrial Systems, 414-423 , 2019 2019 Citations: 1
Optimized solid-state bipolar Marx modulador with resonant type droop compensation H Canacsinh, FA Silva, LM Redondo, L Rocha, V Silva, J Mendes, ... 2017 IEEE 21st International Conference on Pulsed Power (PPC), 1-4 , 2017 2017 Citations: 5
Modeling Marx generators for maximum pulse repetition rate estimation LL Rocha, H Canacsinh, JF Silva, LM Redondo, T Luciano 2017 IEEE 21st International Conference on Pulsed Power (PPC), 1-4 , 2017 2017 Citations: 1
Multilevel high-voltage pulse generation based on a new modular solid-state switch LL Rocha, JF Silva, LM Redondo IEEE Transactions on Plasma Science 42 (10), 2956-2961 , 2014 2014 Citations: 63
Grid integration of offshore wind farms using modular marx multilevel converters L Encarnação, JF Silva, SF Pinto, LM Redondo Doctoral Conference on Computing, Electrical and Industrial Systems, 311-320 , 2012 2012 Citations: 5
A Low Cost Marx Derived Modular Cell for Multilevel Converters L Encarnação, JF Silva, S Pinto, L Redondo XIX El Seminario Anual de Automática, Electrónica Industrial e … , 2012 2012
Modulator for Multilevel High-Voltage Pulse Generation L Encarnação, JF Silva, L Redondo 4th Euro-Asian Pulsed Power Conference – EAAPC 2012 September 30 - October 4 … , 2012 2012
A new modular Marx derived multilevel converter L Encarnação, JF Silva, SF Pinto, LM Redondo Doctoral Conference on Computing, Electrical and Industrial Systems, 573-580 , 2011 2011 Citations: 10
Stability condition based sliding mode modulators for multilevel power converters L Encarnação, JF Silva 2009 35th Annual Conference of IEEE Industrial Electronics, 877-882 , 2009 2009 Citations: 4
Reactive Power Compensation Using Sliding-Mode Controlled Three-Phase Multilevel Converters L Encarnação, JF Silva, V Soares 12th International Conference on Harmonics and Quality of Power–ICHQP … , 2006 2006 Citations: 5
MOST CITED SCHOLAR PUBLICATIONS
Multilevel high-voltage pulse generation based on a new modular solid-state switch LL Rocha, JF Silva, LM Redondo IEEE Transactions on Plasma Science 42 (10), 2956-2961 , 2014 2014 Citations: 63
New backstepping controllers with enhanced stability for neutral point clamped converters interfacing photovoltaics and AC microgrids JD Barros, JFA Silva, L Rocha International Journal of Electrical Power & Energy Systems 153, 109332 , 2023 2023 Citations: 10
A new modular Marx derived multilevel converter L Encarnação, JF Silva, SF Pinto, LM Redondo Doctoral Conference on Computing, Electrical and Industrial Systems, 573-580 , 2011 2011 Citations: 10
Backstepping control of NPC multilevel converter interfacing AC and DC microgrids JD Barros, L Rocha, JF Silva Energies 16 (14), 5515 , 2023 2023 Citations: 9
Backstepping predictive control of hybrid microgrids interconnected by neutral point clamped converters JD Barros, L Rocha, JF Silva Electronics 10 (10), 1210 , 2021 2021 Citations: 9
Interleaved Quadratic Boost DC-DC Converter with Extended Voltage Gain and Reduced Switch Voltage Stress for Photovoltaic Applications D Ferreira, A Cordeiro, P Gambôa, L Rocha, F Barata, JF Silva, JF Martins, ... Open Research Europe 5, 55 , 2025 2025 Citations: 5
Optimized solid-state bipolar Marx modulador with resonant type droop compensation H Canacsinh, FA Silva, LM Redondo, L Rocha, V Silva, J Mendes, ... 2017 IEEE 21st International Conference on Pulsed Power (PPC), 1-4 , 2017 2017 Citations: 5
Grid integration of offshore wind farms using modular marx multilevel converters L Encarnação, JF Silva, SF Pinto, LM Redondo Doctoral Conference on Computing, Electrical and Industrial Systems, 311-320 , 2012 2012 Citations: 5
Reactive Power Compensation Using Sliding-Mode Controlled Three-Phase Multilevel Converters L Encarnação, JF Silva, V Soares 12th International Conference on Harmonics and Quality of Power–ICHQP … , 2006 2006 Citations: 5
Stability condition based sliding mode modulators for multilevel power converters L Encarnação, JF Silva 2009 35th Annual Conference of IEEE Industrial Electronics, 877-882 , 2009 2009 Citations: 4
Virtual Generator to Replace Backup Diesel GenSets Using Backstepping Controlled NPC Multilevel Converter in Islanded Microgrids with Renewable Energy Sources JD Barros, JFA Silva, L Rocha Electronics 13 (22), 4511 , 2024 2024 Citations: 3
Isolated quasi-switched boost integrated T-type DC-DC converter for DC microgrid D Ferreira, A Cordeiro, L Rocha, E Romero-Cadaval, ... 2024 13th International Conference on Renewable Energy Research and … , 2024 2024 Citations: 3
Novel design of the converter for an active UPS application based on marx modulator concept with supercapacitors C Pestana, H Canacsinh, M Chaves, P Gamboa, A Cordeiro, R Luís, ... Doctoral Conference on Computing, Electrical and Industrial Systems, 414-423 , 2019 2019 Citations: 1
Modeling Marx generators for maximum pulse repetition rate estimation LL Rocha, H Canacsinh, JF Silva, LM Redondo, T Luciano 2017 IEEE 21st International Conference on Pulsed Power (PPC), 1-4 , 2017 2017 Citations: 1
Transient analysis modeling of modular Marx multilevel converters LL Rocha, JF Silva, L Encarnação, LM Redondo Proc. 6th Euro-Asian Pulsed Power Conf.-(EAAPC), 1-4 , 2016 2016 Citations: 1
Seven-Level Transformerless Inverter with a Double Boost Controlled Cell D Ferreira, A Cordeiro, L Rocha, JF Silva, E Romero-Cadaval, ... 2024 21st International Conference on Mechatronics-Mechatronika (ME), 1-6 , 2024 2024
A Low Cost Marx Derived Modular Cell for Multilevel Converters L Encarnação, JF Silva, S Pinto, L Redondo XIX El Seminario Anual de Automática, Electrónica Industrial e … , 2012 2012
Modulator for Multilevel High-Voltage Pulse Generation L Encarnação, JF Silva, L Redondo 4th Euro-Asian Pulsed Power Conference – EAAPC 2012 September 30 - October 4 … , 2012 2012
