Hybrid Estimator for Active Reactive Power Control
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Solution Overview
Problem
Conventional power conditioning systems for renewable energy sources face challenges in providing rapid and reliable active/reactive power control, which is essential for smart grid functionality, due to the inherent slowness caused by low-pass filtering in determining active and reactive power requirements.
Innovation Solution
A hybrid estimator is used to quickly estimate the P and Q coefficients based on instantaneous power from a grid-connected inverter, allowing for fast active/reactive power control by determining the difference between reference and estimated values, thereby eliminating the need for low-pass filtering and enhancing control system precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low-pass filtering is used to determine active and reactive power, then measurement accuracy is improved, but control response speed deteriorates
Solution Approach 1:
The patent replaces the mechanical low-pass filtering approach with an adaptive observer-based estimation system. Instead of using physical filters that inherently slow down the response, the system employs mathematical estimation algorithms (adaptive observers) that can rapidly calculate active and reactive power values without the bandwidth limitations of traditional filters, thus maintaining measurement accuracy while dramatically improving control response speed
Solution Approach 2:
The patent changes the fundamental parameter estimation approach from direct measurement through filtering to adaptive estimation using observer algorithms. By modifying how power parameters are derived (from filtered measurements to model-based estimation), the system achieves both high accuracy and fast response simultaneously, resolving the contradiction between precision and speed
2Device complexity
If conventional control systems are used, then system simplicity is maintained, but smart grid functionality is insufficient
Solution Approach 1:
The patent implements a control system that provides multiple smart grid functions through a unified architecture. The adaptive observer-based control system simultaneously delivers fast active/reactive power control, voltage regulation, and rapid response to grid disturbances, making the system versatile enough to handle various smart grid requirements without requiring separate specialized systems for each function
Solution Approach 2:
The patent introduces dynamic adaptation capabilities into the control system through adaptive observers that continuously adjust their estimation based on real-time system conditions. This dynamic behavior enables the system to respond flexibly to changing grid requirements and provide intelligent control functions, transforming a static control system into one that can adapt to various smart grid scenarios
Data Source
AI summary
Systems, methods, and devices for use with active/reactive power control in power conditioning systems. To provide quick active/reactive power control by way of a grid-connected inverter, an estimator estimates the P and Q coefficients based on an instantaneous power from the grid-connected inverter. The estimator receives grid current and voltage and estimates of the P and Q coefficients are used with reference P and Q values to determine whether active or reactive power needs to be injected to the grid. The P coefficient is a DC offset of the instantaneous power of the grid and the Q coefficient is the coefficient of a sine component of the instantaneous power.