Unified Power Flow Controller With Common DC Bus Voltage Regulation
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Solution Overview
Problem
Power systems face challenges in maintaining stable power characteristics, such as voltage levels and harmonic content, due to fluctuations in load conditions and power sources.
Innovation Solution
A power system architecture that includes a unified power flow controller (UPFC) with a shunt converter and a series converter, both connected via a common DC bus, allowing for active and reactive power control, voltage regulation, and harmonic filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional separate control of shunt and series converters is used, then device complexity is reduced, but power flow control capability and voltage regulation performance deteriorate
Solution Approach 1:
The patent merges the control of shunt and series converters into a unified control framework. The common DC bus couples both converters, allowing shared control strategies that coordinate reactive power compensation (shunt) and active power flow control (series) simultaneously, enhancing overall power flow control capability while managing complexity through integration.
Solution Approach 2:
The unified control system performs multiple functions: it regulates voltage levels, controls active and reactive power flow, and maintains DC bus voltage stability. By making the control system universal, it can handle diverse power system conditions and requirements through a single integrated approach rather than separate specialized controllers.
2Reliability
If unified control of shunt and series converters is implemented, then voltage regulation and power control performance is improved, but device complexity increases
Solution Approach 1:
The common DC bus acts as an intermediary element that couples the shunt and series converters. This intermediary structure enables coordinated control by providing a shared energy interface, allowing the control system to regulate voltage and power flow more effectively while the modular converter design keeps the overall architecture manageable.
Solution Approach 2:
The unified control system employs feedback mechanisms to monitor DC bus voltage, line voltage, and power flow conditions. Based on these feedback signals, the controller dynamically adjusts the firing angles and switching patterns of both shunt and series converters, maintaining voltage regulation stability and reliable operation under varying load conditions.
3Productivity
If multiple converters are coupled via common DC bus, then power system efficiency and reliability are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The unified power flow controller is segmented into modular shunt and series converter units, each with its own IGBT-based voltage source converters. This segmentation allows for standardized manufacturing of individual converter modules that can be assembled and configured based on specific application requirements, reducing overall manufacturing complexity while maintaining high power system efficiency.
Data Source
AI summary
Examples of the disclosure include a power system having a first converter configured to be coupled in parallel with a power transmission line, the first converter including a plurality of shunt sub-modules configured to be coupled in series between the power transmission line and a reference node, a second converter configured to be coupled in series with the power transmission line, the second converter including a plurality of series sub-modules coupled in parallel with each other, and a common DC bus coupled to the first converter and the second converter.