Inverter Converter Control via Droop Function and Voltage Regulation
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Solution Overview
Problem
Inverter-based resources face stability challenges in grids with low penetrations of synchronous generators, as they struggle to maintain stable power and frequency due to increased wind power penetration, leading to potential destabilization and limitations in grid stability.
Innovation Solution
A converter control method that applies a droop function to grid parameters to generate a power droop signal, combined with fast closed-loop voltage control and power constraints, allowing for rapid power output adjustments to grid frequency changes while limiting adverse impacts, thereby enhancing stability in systems with low synchronous generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inverter-based resources rely on stable grid voltage and frequency from synchronous generation, then they can operate stably, but they approach stability limitations as synchronous generation penetration approaches 0%
Solution Approach 1:
The patent changes the control parameters of inverter-based resources by implementing fast-frequency droop functions with response times of 10-100ms and fast closed-loop voltage control, transforming them from passive grid-following devices to active grid-supporting devices that can maintain stability without synchronous generation
Solution Approach 2:
The patent segments the power command signal into multiple components including base power, frequency droop power, and constrained power portions, allowing independent control of different functional aspects to achieve both fast response and stability
2Productivity
If wind power penetration into the grid increases significantly, then more clean energy is generated, but wind turbine generators have a significant impact on grid voltage and frequency
Solution Approach 1:
The patent implements feedback mechanisms where inverter-based resources continuously monitor grid frequency and voltage parameters, then adjust their power output and terminal voltage in real-time to counteract disturbances and maintain grid stability
Solution Approach 2:
The patent makes the inverter-based resource control dynamic by implementing fast response capabilities with droop functions that automatically adjust power output based on real-time grid conditions, enabling adaptation to varying wind power penetration levels
3Speed
If inverter-based resources provide fast power response to grid frequency changes, then grid stability is improved, but converter controls may become destabilized without proper voltage regulation
Solution Approach 1:
The patent merges fast-frequency droop control with fast closed-loop terminal voltage control into a unified control system, where both functions operate simultaneously to provide fast power response while maintaining converter control stability through coordinated voltage and power regulation
4Device complexity
If inverter-based resources are controlled as current sources based on fundamental voltage waveforms, then control is simple, but they cannot handle significant grid voltage and frequency disturbances
Solution Approach 1:
The patent transforms the static current source control into a dynamic control system that actively responds to grid disturbances through fast-frequency droop functions and real-time voltage regulation, enabling adaptation to significant voltage and frequency variations
Data Source
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AI summary
A method for controlling an inverter-based resource (IBR) connected to an electrical grid includes receiving grid parameter(s) and applying a droop function to the grid parameter(s) to determine a power droop signal. Further, the method includes receiving a power reference signal. Moreover, the method includes determining a power command signal as a function of the power droop signal and the power reference signal to allow for a fast response in a power output of the IBR to the grid parameter(s). The method also includes applying power constraint(s) to the power command signal to limit how much the power output of the IBR can be changed due to the grid parameter(s). Further, the method includes determining one or more control commands for the IBR based, at least in part, on the power command signal. Thus, the method includes controlling the IBR based, at least in part, on the power command signal.