Microgrid Power Apportionment via DC Link Bus and Source Prioritization
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Solution Overview
Problem
Microgrids face challenges in efficiently managing power from multiple, varying DC and AC sources to ensure reliable and consistent output to loads, particularly during interruptions or when sources have different voltage levels, capacities, and types, including renewable and non-renewable energy sources.
Innovation Solution
A microgrid control system that detects and compares characteristic power features of multiple sources, determines an apportionment of power, and selectively connects sources to meet load requirements through a DC link bus and inverter system, allowing for voltage adjustment and source prioritization based on capacity, cost, and availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple power sources with different voltage levels and capacities are connected to the microgrid, then the power supply reliability and adaptability are improved, but the system complexity and control difficulty increase
Solution Approach 1:
The patent introduces a DC link bus as an intermediary component between multiple power sources and the load. This DC link bus serves as a common platform that standardizes voltage levels and simplifies the connection architecture, allowing diverse power sources (solar panels, wind turbines, batteries, grid connections) to be integrated without requiring complex direct coordination between each source. The inverter system acts as another intermediary that manages the conversion and distribution of power from the DC link to AC loads, thereby reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The microgrid system is designed with universal interfaces and standardized DC voltage levels that can accommodate multiple types of power sources with different characteristics. The control system provides multi-functional capabilities including maximum power point tracking (MPPT) for renewable sources, charge control for batteries, and grid synchronization, all through a unified control architecture. This universality allows the system to handle diverse power sources without requiring separate specialized systems for each type.
2Reliability
If power from multiple sources is aggregated and converted, then the power delivery reliability is improved, but the conversion losses increase
Solution Approach 1:
The system performs preliminary power aggregation at the DC link bus level, where multiple DC power sources are combined before conversion to AC. By consolidating DC sources first and then using a single or coordinated inverter system for AC conversion, the number of DC-AC conversion stages is minimized. This preliminary aggregation approach reduces the total number of conversion operations compared to converting each DC source individually to AC, thereby reducing cumulative conversion losses while maintaining reliable power delivery through diversified sources.
3Productivity
If the microgrid selectively connects power sources based on apportionment, then the power distribution efficiency is improved, but the control system complexity increases
Solution Approach 1:
The control system implements feedback mechanisms that continuously monitor the status of multiple power sources (availability, output level, health status) and the load requirements. Based on this real-time feedback, the system dynamically adjusts the apportionment of power from different sources and controls the switching of source connections. This feedback-driven approach enables efficient power distribution while using standardized control algorithms that can be implemented through microcontrollers or DSPs, balancing distribution efficiency with manageable control complexity.
4Ease of operation
If DC voltage levels are standardized and matched, then the system compatibility and ease of operation are improved, but the flexibility in handling different voltage sources decreases
Solution Approach 1:
The system employs DC-DC converters with adjustable transformation ratios that can adapt to different input voltage levels from various power sources while outputting to a standardized DC link voltage. By dynamically changing the conversion parameters (turns ratio, switching frequency, duty cycle) of these converters, the system maintains standardized voltage levels for ease of operation and connection, while simultaneously preserving flexibility to accept diverse voltage sources including solar panels, wind turbines, and battery systems with varying voltage characteristics.
Data Source
AI summary
A microgrid control system that can govern power provided to a load from various power sources. The microgrid control system can determine apportionment of power between the various sources based on characteristic power features of the various sources.