DFIG Power Generation Parallel Converter Control
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Solution Overview
Problem
Hybrid power generation systems with doubly-fed induction generators (DFIG) face limitations in evacuating electrical power from auxiliary sources like photovoltaic (PV) due to rated power constraints of converters and slip power, leading to power wastage and reduced production.
Innovation Solution
A control sub-system with switching elements and a controller connects the rotor-side converter in parallel with the line-side converter based on operating parameters, enhancing power production by optimizing power flow between the DFIG and the secondary power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the secondary power source is coupled to the DFIG via power converter(s), then electrical power can be generated and supplied to electrical loads and/or electric grid, but the evacuation of electrical power is limited by rated power of converters and slip power of DFIG
Solution Approach 1:
The patent merges the rotor-side converter and line-side converter into a unified power conversion system where the secondary power source is coupled to both converters. This allows the secondary power to be distributed through both conversion paths, effectively increasing the total evacuation capacity beyond the limitation of a single converter's rated power.
Solution Approach 2:
The system dynamically adjusts the operation mode between grid-connected and islanded modes, and flexibly controls the power flow distribution between the two converters based on real-time operating conditions. This dynamic adaptability allows the system to maximize power evacuation capacity under different operational scenarios.
2Reliability
If the rated power of converters and slip power of DFIG limit power evacuation, then system operation is stable, but excess electrical power from auxiliary power source is curtailed leading to power wastage
Solution Approach 1:
The patent changes the operational parameters by introducing a second power conversion path (secondary power source coupled to both converters). This parameter change enables the system to handle higher power levels and utilize excess power that would otherwise be curtailed, converting the limitation into an opportunity for enhanced power utilization.
Solution Approach 2:
The secondary power source is integrated with multi-functionality, serving both as a primary power contributor and as a means to utilize excess power from auxiliary sources. The dual-converter configuration allows the system to perform multiple functions: grid power conversion, auxiliary power integration, and excess power evacuation simultaneously.
3Power
If limited evacuation capacity is imposed by power converter(s) and slip power of DFIG, then converter operation is within rated capacity, but integration capacity for electrical power from auxiliary power source is greatly limited
Solution Approach 1:
The patent segments the power conversion function into two independent but coordinated converters: the rotor-side converter and the line-side converter. By coupling the secondary power source to both segments, the system creates multiple integration pathways, significantly enhancing the adaptability and integration capacity for auxiliary power sources while keeping each converter within its rated capacity.
Data Source
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AI summary
A power generation system (100, 200, 300, 400) is presented. The power generation system includes a prime mover (102), a doubly-fed induction generator (DFIG) (104) having a rotor winding (126) and a stator winding (122), a rotor-side converter (106), a line-side converter (108), and a secondary power source (110, 401) electrically coupled to a DC-link (128). Additionally, the power generation system includes a control sub-system (112, 212, 312) having a controller, and a plurality of switching elements (130, and 132 or 201). The controller is configured to selectively control switching of one or more switching elements (130, and 132 or 201) based on a value of an operating parameter corresponding to at least one of the prime mover, the DFIG, or the secondary power source to connect the rotor-side converter in parallel to the line-side converter to increase an electrical power production by the power generation system.