Solar Power Converter Reactance Estimation for Grid Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Utility-scale solar power conversion systems face challenges in connecting to the power grid due to difficulties in measuring and managing system parameters, particularly reactive power, which can lead to voltage fluctuations and safety concerns.
Innovation Solution
A solar power conversion system that includes a photovoltaic array, a power converter, and a transformer coupled to the power grid, featuring a reactance estimation module and a maximum reactive power estimation module to generate switching command signals for the power converter, ensuring effective control and minimizing voltage fluctuations by estimating short circuit reactance and maximum reactive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If reactive power is transferred to the power grid, then power conversion capability is improved, but voltage fluctuations occur and grid safety is compromised
Solution Approach 1:
The system continuously monitors voltage at the point of common coupling (PCC) and uses this feedback to dynamically adjust reactive power transfer. The controller estimates short circuit reactance and maximum reactive power based on real-time voltage measurements, creating a closed-loop control system that prevents voltage fluctuations while maximizing reactive power transfer capability.
Solution Approach 2:
The system changes operating parameters dynamically by estimating short circuit reactance and maximum reactive power based on varying grid conditions. The controller adjusts reactive power transfer limits according to real-time voltage measurements and estimated system parameters, allowing optimal power transfer while maintaining safety under different operating conditions.
2Measurement precision
If system parameters are measured for grid connectivity control, then control precision is improved, but measurement capability requirements increase
Solution Approach 1:
The system uses voltage measurement at the PCC as an intermediary parameter to indirectly determine other critical system parameters. Instead of requiring direct measurement of short circuit reactance and maximum reactive power, the controller estimates these parameters based on voltage measurements and system models, reducing measurement requirements while maintaining control precision.
Solution Approach 2:
The system replaces physical measurement devices with computational estimation methods. The controller uses mathematical models and algorithms to estimate short circuit reactance and maximum reactive power based on voltage measurements, substituting complex measurement hardware with software-based parameter estimation techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for precise control of reactive power transfer, predicting the amount that can be transferred without exceeding the maximum voltage limit of the power converter, thereby stabilizing voltage and enhancing grid connectivity.
Implementation Method 1
a photovoltaic array having photovoltaic modules for generating direct current (DC) power
Implementation Method 2
a power converter for converting the DC power to alternating current (AC) power
Data Source
Figure 1
Figure 2~3
AI summary
A solar power conversion system includes a photovoltaic array having photovoltaic modules for generating direct current (DC) power. A power converter is provided in the system for converting the DC power to alternating current (AC) power. A transformer is coupled between the power converter and a power grid for transmitting the AC power to the power grid. The transformer is connected to the power grid at the point of common coupling (PCC) and to the power converter at output terminals. A reactance estimation module is provided in the system for estimating a short circuit reactance at PCC based on a small change in a measured voltage at output terminals with respect to a small change in a measured reactive power at the output terminals. Further, a maximum reactive power estimation module estimates a maximum reactive power based on the estimated reactance, the measured voltage at output terminals, and the measured reactive power at the output terminals. A controller in the system generates switching command signals for the power converter based on the measured voltage at output terminals and the estimated maximum reactive power.