17 research outputs found
Optimal PV and Battery Sizing for a Space Microgrid Near the Lunar South Pole Considering ISRU, Habitat and Water Subsystem Power Demand
No full textDiptish Saha, Aalborg University, DenmarkNajmeh Bazmohammadi, Aalborg University, DenmarkJuan C. Vasquez, Aalborg University, DenmarkJosep M. Guerrero, Aalborg University, DenmarkICES501: Life Support Systems Engineering and AnalysisThe 52nd International Conference on Environmental Systems was held in Calgary, Canada, on 16 July 2023 through 20 July 2023.The size and mass of the payload substantially affect the cost of space missions. The aim of this paper is to investigate the optimal mass and size of the photovoltaic (PV) array and battery in a PV-battery-powered lunar microgrid (MG) at 15 highly illuminated candidate sites near the lunar south pole. It is assumed that PV arrays are installed on top of towers with a height of 10 m. The methodology to estimate the PV output power at each candidate site using the illumination time-series profile is presented. On the consumption side, the power demand profiles of ISRU and wastewater subsystems are determined using the estimated oxygen and water consumption profiles of the habitat with four crew members. The closed-loop model of water management includes the interaction of ISRU, wastewater filtration system, and the crew habitat. The power consumption profile of the crew habitat is generated considering different power-consuming components in the habitat as well as the daily schedule of the crew members. Organizing different loads in a multi-microgrid system is also investigated. Finally, a criterion, mass-per-unit-load (MPUL), is used to compare different sites and select the best location with the minimum PV-battery system mass that can serve the highest power demand
Implementation of Model Predictive Control for Conventional Switched Capacitor Multilevel Inverter to Reduce Input Current Peak and Capacitor Voltage Ripple
No full textWith the increase in the use of renewable sources, there has been a significant topological development of multilevel inverters (MLIs). A number of MLI topologies have been developed in recent years which opens significant possibilities for further improving the robustness and efficiency of the inverter systems. Switched Capacitor Multilevel Inverter (SC-MLI) is a novel MLI structure introduced recently which requires a reduced number of power supplies in comparison with the conventional multilevel inverters. In SC-MLI, capacitors are used as alternative dc sources. Further, SCMLI possesses the voltage boosting capability and self-capacitor voltage balancing ability. One of the major limitations of SCMLI is that the input current is discontinuous and has an extremely high peak which may damage the input source and the components associated with it. Hence, the controlling of input current is required. Further, the controlling of output current of inverter, an appropriate control strategy has to be employed. For achieving these, in this paper Model Predictive Control (MPC) strategy has been implemented for basic SC-MLI unit. Extensive simulation study of 5-level SCMLI in MATLAB/Simulink shows that by using MPC, the inverter can produce the voltage levels in such way that the desired load current is achieved. Further, the peak magnitude of input current and capacitor voltage ripple are significantly reduced as compared to open loop control strategy
A New Symmetrical Three Phase Multilevel Inverter using Switched Capacitor Basic Units for Renewable Energy Conversion Systems
No full textDue to increase in availability of renewable energy sources, development of multilevel inverter topologies has become an interesting research area for researchers in recent years to further improve the effectiveness of inverter systems. Multilevel inverter (MLI) with switched capacitor as the basic unit is a notable development in MLI topologies which reduces the number of power supplies required in comparison to the conventional MLIs and are widely known as switched capacitor multilevel inverter (SCMLI). In SCMLI, multiple power supplies can be replaced by capacitors which are used in tandem to boost the output voltage. Further, they possess capacitor voltage balancing capability. In this paper, a novel switched capacitor based three phase MLI for renewable energy conversion systems is presented using phase disposition PWM (PDPWM) modulation technique. The proposed three phase MLI is modular in nature and number of source modules can be increased to get more number of output voltage levels. A comparison study between the proposed topology and the recently developed three phase MLI topologies has been discussed in different perspective such as required components, maximum output voltage generation, capacitor voltage balancing capability etc. Further, an extensive simulation study is done in MATLAB/SIMULINK to validate the effectiveness and feasibility of the proposed topology
A novel structure of cascaded multilevel inverter with reduced device count
No full textIn this paper, a novel structure of cascaded multilevel inverter (MLI) is proposed. Each module of the proposed MLI consists of three numbers of DC sources and eight power switching devices. Each module possesses the capability of generating bipolar voltage level at its output terminals. Hence, the topology is analyzed for symmetrical and asymmetrical DC source configurations. Two types of asymmetrical DC source configuration algorithms have been proposed. As compared with existing MLI topologies, the proposed MLI requires lower components such as switching devices, driver circuits to generate specific number of output voltage level. This further reduces the size and cost of the inverter system. Extensive simulation studies of 7 level symmetrical and 11 level asymmetrical structures of proposed MLI have been done in Simulink /MATLAB. The different results of simulation studies prove the effectiveness of the proposed topology
Multiple Microgrids: A Review of Architectures and Operation and Control Strategies
Get PDFSeveral issues of individual microgrids (MGs) such as voltage and frequency fluctuations mainly due to the intermittent nature of renewable energy sources’ (RESs) power production can be mitigated by interconnecting multiple MGs and forming a multi-microgrid (MMG) system. MMG systems improve the reliability and resiliency of power systems, increase RESs’ utilization, and provide cost-efficient power to the consumers. This paper provides a comprehensive review of the conducted studies in the MMG area summarizing different operational goals and constraints proposed in the literature for efficient operation of MMGs. Besides, different MMG architectures in which the MGs can be interconnected to form an MMG system and their characteristics are discussed. This paper also provides a state-of-the-art review on different control strategies and operation management methodologies for the operation and control of MMGs in centralized, decentralized, distributed, and hierarchical structures. A classification of different sources of uncertainties in an MMG system and proposed uncertainty handling strategies are also presented. Finally, the paper is complemented with a discussion of the main open issues and future research directions of MMG systems
Optimal PV and Battery Sizing for a Space Microgrid Near the Lunar South Pole Considering ISRU, Habitat and Water Subsystem Power Demand
Get PDFThe size and mass of the payload substantially affect the cost of space missions. The aim of this paper is to investigate the optimal mass and size of the photovoltaic (PV) array and battery in a PV-battery-powered lunar microgrid (MG) at 15 highly illuminated candidate sites near the lunar south pole. It is assumed that PV arrays are installed on top of towers with a height of 10 m. The methodology to estimate the PV output power at each candidate site using the illumination time-series profile is presented. On the consumption side, the power demand profiles of ISRU and wastewater subsystems are determined using the estimated oxygen and water consumption profiles of the habitat with four crew members. The closed-loop model of water management includes the interaction of ISRU, wastewater filtration system, and the crew habitat. The power consumption profile of the crew habitat is generated considering different power-consuming components in the habitat as well as the daily schedule of the crew members. Organizing different loads in a multi-microgrid system is also investigated. Finally, a criterion, mass-per-unit-load (MPUL), is used to compare different sites and select the best location with the minimum PV-battery system mass that can serve the highest power demand
Optimal Scheduling of Rover Charging for Lunar Power Systems
Get PDFExtra-vehicular activities (EVAs) using pressurized and unpressurized rovers are planned by different space agencies to explore the lunar surface. The battery-powered lunar rovers can be charged from the lunar power systems, called lunarmicrogrids (MGs). These MGs are required to maintain reliable operations even in harsh and resource-scarce environments like space, fulfilling the mission’s long- and short-term goals, considering the power and resource availability, power demand, and system constraints. Preparing for an upcoming EVA demands intelligent strategies for planning the MG’s operation for autonomous power control (APC), energy management systems (EMS), and charging of rovers. The optimal operation of MGs can be affected by arbitrarily charging the rovers, altering the MG’s planned resource availability, and compromising the mission’s safety and reliability. This paper proposes an optimization framework to charge the lunar rovers optimally, considering the desired period of EVA and MG’s operational requirements. This defines well-designed operating references for MG’s APC and EMS. To investigate the performance of the proposed scheduling framework, two case studies are considered. In the first case, the paper considers the habitat MG to be supplied from its own PV-battery MG, to which the rover is also connected. The power demand profile of the habitat MG is modeled considering several activities in the habitat and wastewater filtration process. It can be observed that the optimization framework schedules the rover’s optimal charging duration and power from the excess PV power that would otherwise have been shed. In the second case, a multi-microgrid (MMG) system consisting of the habitat and in-situ resource utilization (ISRU) MGs is considered with power transmission among them, and it is assumed that the rover is charged from the habitat MG. The ISRU MG is also considered to be supplied from its PV-battery MG to supply its power demand for producing life-supporting resources according to the needs of the habitat. It is observed that the excess PV power from the ISRU MG is transmitted to charge the rover and maintain the battery state-of-charge (SoC) at the desired level
A Novel Heuristic Algorithm Integrating Battery Digital-Twin-Based State-of-Charge Estimation for Optimized Electric Vehicle Charging
Get PDFThe increasing need for effective electric vehicle (EV) charging solutions in the context of transportation electrification has become a significant challenge. This system introduces an innovative algorithm, named Energy Distribution and Node Allocation using Evolutionary and Resourceful Optimization (ENDEAVOR), designed to elevate the efficiency of EV charging through the integration of a battery’s digital twin. This cutting-edge algorithm offers precise estimations of EV charging time, seamlessly updating both the State of Charge (SOC) via the Unscented Kalman Filter (UKF) and the internal battery resistance using parameterization, while sending this information to the cloud. ENDEAVOR optimizes charging-node allocation and intelligently distributes energy among incoming EVs based on their specific charging requests, all within the context of renewable-energy-sourced charging stations. The incorporation of a digital twin for the battery confers several benefits, including highly accurate SOC and charging-time estimates that ultimately enhance the overall efficiency of the charging process. This algorithm further optimizes energy distribution, resulting in significantly improved charging-time predictions, reduced wait times for users, and an enhanced overall experience for the user. The day-to-day implications of these enhancements are remarkable, culminating in substantial annual energy savings of approximately 180 units. ENDEAVOR has the potential to revolutionize the landscape of EV charging
