Solar Power Frequency Control via Grid Reference Comparison
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Solution Overview
Problem
Solar power generation systems lack the frequency-regulating capability to stabilize grid frequency, which is essential for grid stability and reliability as the variability of solar power becomes less acceptable to utility companies.
Innovation Solution
A solar power generation system with an integrated control system that includes a power point tracker, frequency monitor, internal reference frame element, frequency comparator, and command signal generator, along with an energy storage unit, to compare network and internal reference frequencies and adjust output power or energy storage accordingly to stabilize grid frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solar power generation systems are increased to meet energy demands, then productivity is improved, but grid frequency stability deteriorates due to lack of frequency-regulating capability
Solution Approach 1:
The patent introduces an energy storage unit as an intermediary between the solar power generation system and the grid. This mediator absorbs excess power during high generation periods and releases power during low generation periods, thereby stabilizing grid frequency while allowing increased solar penetration. The energy storage unit acts as a buffer that decouples the variability of solar generation from the grid frequency requirements.
Solution Approach 2:
The control system dynamically changes the operating parameters of the solar power generation system based on grid frequency conditions. When grid frequency deviates from nominal values, the system adjusts its power output by modifying the DC-link voltage and inverter switching parameters, enabling the solar system to provide frequency regulation services while maintaining maximum power point tracking under normal conditions.
2Productivity
If maximum power point tracking control is used to maximize solar power output, then productivity is improved, but frequency stabilization capability deteriorates
Solution Approach 1:
The system dynamically switches between maximum power point tracking mode and frequency regulation mode based on grid conditions. During normal operation, the system operates in MPPT mode to maximize power extraction. When grid frequency deviations are detected, the control system transitions to frequency regulation mode, dynamically adjusting power output to support grid frequency while the energy storage unit compensates for the reduction in solar power extraction.
3Reliability
If solar power generation systems are equipped with frequency regulation capability, then grid frequency stability is improved, but device complexity increases due to additional control systems and energy storage
Solution Approach 1:
The control system is designed to perform multiple functions: maximum power point tracking, frequency regulation, and coordination with energy storage management. By integrating these functions into a single control architecture that monitors both solar irradiance and grid frequency, the system achieves frequency stabilization capability without proportionally increasing complexity. The same power electronic converters used for power extraction are also utilized for frequency regulation, avoiding the need for separate dedicated equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables solar power generation systems to provide frequency stabilization, enhancing grid stability and reliability, allowing for increased solar penetration in power networks by damping frequency oscillations and supporting grid frequency during transient conditions.
Implementation Method 1
Solar power generation systems have photovoltaic (PV) modules, which produce electrical power
Data Source
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Figure 3~4
AI summary
A solar power generation system (10) includes a control system (20) and a DC to AC converter (16) coupled to a photovoltaic (PV) module (14) and for supplying power to a power network (18). The control system includes a power point tracker (22) to extract either maximum power available from the PV module or less than maximum power available from the PV module, a frequency monitor (24) to obtain a network frequency from the power network, an internal reference frame element (26) to provide an internal reference frequency of the solar power generation system, a frequency comparator (28) to compare the network frequency and the internal reference frequency, and a command signal generator (30) to use the frequency comparison to determine whether a transient increase or decrease in commanded output power is warranted and to provide a command signal.