Inverter Voltage Distortion Reduction via Active Feedback Control
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Solution Overview
Problem
Inverter-based resources, such as wind turbines, generate voltage distortion that conventional systems struggle to control effectively, often requiring external filters which can lead to instability and increased costs due to the need to compensate for both internal and external distortion sources.
Innovation Solution
A method and system that generates trim signals to compensate for voltage distortion caused by the inverter's nonlinearities, focusing on extracting and addressing distortion components specific to the inverter-based resource, rather than external sources, using a controller to determine and apply a voltage command that reduces internal distortion while being insensitive to external distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If external filters are used to reduce voltage distortion, then voltage distortion is reduced, but system stability deteriorates due to closed-loop instability risks
Solution Approach 1:
The patent extracts and eliminates the need for external filters by implementing an active distortion compensation system within the power converter control. The controller identifies distortion components from voltage feedback signals and generates compensation signals that cancel these distortions, removing the harmful dependency on external filtering equipment while maintaining system stability through controlled feedback mechanisms.
Solution Approach 2:
The patent implements a feedback-based distortion compensation system where voltage feedback signals are continuously monitored, distortion components are extracted through signal processing, and compensation signals are generated and applied back to the power converter. This closed-loop feedback mechanism reduces voltage distortion while maintaining stability by dynamically adjusting compensation based on actual measured distortion levels.
2Object-generated harmful factors
If active filters are used to compensate for distortion, then voltage distortion is reduced, but device complexity increases due to additional equipment requirements
Solution Approach 1:
The patent makes the power converter controller multi-functional by integrating distortion compensation capabilities into the existing control architecture. The same controller that manages power conversion also performs distortion identification, signal processing, and compensation generation, eliminating the need for separate active filter equipment and reducing overall system complexity while maintaining distortion reduction functionality.
Solution Approach 2:
The patent merges the distortion compensation function with the power converter control system. By combining the controller, signal processing units, and compensation signal generation into the existing power conversion architecture, the system eliminates standalone filter equipment and reduces device complexity while achieving effective voltage distortion reduction through integrated control.
3Object-generated harmful factors
If active filters are rated to compensate for external background distortion, then external distortion is addressed, but cost increases due to oversized filter ratings
Solution Approach 1:
The patent applies local quality by focusing distortion compensation specifically on internally generated distortion components rather than attempting to compensate for all distortion including external background sources. The controller identifies and compensates only for distortion originating from the power converter and associated equipment, using appropriately sized compensation capacity matched to the actual local distortion source, thereby avoiding oversized ratings and reducing system cost.
Data Source
AI summary
A method for operating a inverter-based resource connected to a power grid includes receiving one or more voltage feedback signals created by at least one component of the inverter-based resource, wherein distortion components of the one or more voltage feedback signals are more sensitive to voltage distortion created by the inverter-based resource than by external sources of voltage distortion. Further, the method includes extracting a distortion component of the one or more feedback signals having a certain phase sequence and frequency. Moreover, the method includes determining a voltage command for the power converter as a function of, at least, the distortion component. Thus, the method includes controlling the power converter based on the voltage command such that the voltage distortion created by the at least one component of the inverter-based resource is reduced in a manner that is relatively insensitive to voltage distortion created by sources external to the inverter-based resource.