Smart Inverter Adaptive Control for DER Voltage Stability
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Solution Overview
Problem
The increasing adoption of distributed energy resources (DER) such as rooftop photovoltaic (PV) generation systems introduces voltage instability challenges due to improper management and potential exploitation of smart inverter vulnerabilities, necessitating an adaptive control approach to stabilize the system.
Innovation Solution
An adaptive control approach using a Model Reference Adaptive Controller (MRAC) adjusts VV/VW control functions and active/reactive power injections of DER, employing a low pass filtered AC grid voltage as a decentralized, model-free reference model to mitigate voltage instabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If autonomous control functions (VV/VW controllers) are deployed in DER systems, then local voltage correction capability is improved, but system stability deteriorates due to hunting oscillations
Solution Approach 1:
The patent implements a supervisory control system that continuously monitors voltage measurements from multiple DER systems and adjusts VV/VW controller parameters in real-time based on system conditions. This feedback mechanism prevents hunting oscillations by dynamically adapting control parameters to maintain stability while preserving local voltage correction capabilities.
Solution Approach 2:
The system dynamically adjusts the parameters of VV/VW controllers based on real-time voltage measurements and system conditions. The supervisory controller modifies control characteristics adaptively, allowing the system to transition between different operational states to maintain stability while enabling effective local voltage correction when needed.
2Productivity
If steep slopes of VV control curves are used, then reactive power injection response is improved, but voltage instability increases leading to hunting phenomenon
Solution Approach 1:
The supervisory control system dynamically changes the parameters of VV/VW control curves based on system conditions. When voltage instability is detected, the system adjusts the slope parameters to prevent hunting while maintaining adequate reactive power injection capability. This allows the control curves to adapt their characteristics in real-time rather than using fixed steep slopes.
3Adaptability or versatility
If remote update capability is implemented in smart inverters, then system adaptability is improved, but security vulnerability increases due to potential malicious exploitation
Solution Approach 1:
The patent introduces a supervisory control system as an intermediary layer between the external network and individual DER systems. This intermediary authenticates and validates all remote update commands before applying them, preventing malicious exploitation while maintaining the ability to adaptively update control parameters through verified channels.
4Productivity
If multiple DER systems operate autonomously, then self-generation capability is improved, but coordination difficulty increases making power system management challenging
Solution Approach 1:
The supervisory control system provides universal coordination functionality that works across multiple different DER systems with various autonomous control capabilities. It establishes a common framework for communication and coordination that simplifies power system management while preserving the self-generation capabilities of individual DER systems.
Data Source
AI summary
One or more embodiments relates to a smart inverter used in a photovoltaic (PV) generation system. In one embodiment, the smart inverter includes a PV control logic device; and at least one low pass filter coupled to and in communication with the at least one PV control logic device.