PV Inverter Feed-In Control via Fractional Factor
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Solution Overview
Problem
The integration of increasing photovoltaic solar systems into public power supply networks poses challenges due to temporal fluctuations in energy feed-in and consumption, leading to potential network failures and financial losses for solar system operators, as existing methods either switch off systems or result in conflicts of interest between energy suppliers and operators.
Innovation Solution
Implementing a method where photovoltaic solar systems are partially shut down by a fractional factor determined by the energy supplier, allowing continuous energy feed-in while reducing peak power, with each system having a data transmission device to measure and report energy values, enabling precise compensation for operators and central control by the energy supplier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photovoltaic solar systems feed maximum possible power into the grid, then energy feed-in is maximized, but network stability deteriorates during peak solar radiation and low consumption periods
Solution Approach 1:
The patent implements dynamic control of PV system feed-in power through a fractional factor that varies over time. The control unit adjusts the feed-in power continuously based on current grid conditions (consumption and feed-in requirements), transitioning from static maximum feed-in to dynamic adaptive feed-in. This resolves the contradiction by allowing maximum feed-in when grid conditions permit while reducing feed-in when stability is at risk.
Solution Approach 2:
The patent changes the operational parameter of feed-in power from a fixed maximum value to a variable value determined by a fractional factor. The control unit modifies the feed-in power parameter based on real-time grid conditions, enabling the system to adapt between maximum feed-in (when stable) and reduced feed-in (when unstable), thus resolving the contradiction between productivity and reliability.
2Reliability
If photovoltaic solar systems are switched off to reduce feed-in power, then network stability is improved, but operator profitability deteriorates
Solution Approach 1:
Instead of completely switching off PV systems (100% reduction), the patent applies partial action by reducing feed-in power to a level defined by a fractional factor between 0 and 1. This partial reduction is sufficient to maintain network stability while preserving the majority of feed-in power and operator profitability, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit receives information about current consumption and feed-in requirements from the energy supplier, calculates an appropriate fractional factor, and adjusts feed-in power accordingly. This closed-loop feedback ensures that profitability is maintained by only reducing feed-in when necessary for network stability, rather than complete shutdowns.
3Power
If complete shutdown of solar systems is implemented, then feed-in power is reduced, but measurement and compensation accuracy deteriorates
Solution Approach 1:
The patent ensures continuous operation of PV systems by maintaining feed-in power at a non-zero level defined by the fractional factor. This continuity allows the measurement device to continuously measure feed-in energy without interruption, preserving measurement precision and enabling accurate compensation calculations, thus resolving the contradiction between power reduction and measurement accuracy.
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 approach allows energy suppliers to manage feed-in power effectively, preventing network failures and ensuring operators are financially compensated for their maximum possible feed-in energy, while maintaining system profitability.
Implementation Method 1
Each of the solar systems has a solar inverter and a calibrated feed-in energy meter on the AC side of the solar inverter
Data Source
Figure 1
AI summary
In an electrical grid (30) of a power supply utility the feed capacities of the photovoltaic installations (10) are controlled depending on feed requirements, the feed capacities of the photovoltaic installations (10) being reduced to a fraction factor (B) of the maximum possible feed capacity, which fraction factor is unequal zero. Each photovoltaic installation (10) comprises a photovoltaic inverter (20) and a feed power meter (50) on the AC side (20b) of the photovoltaic inverter (20), the feed power meter (50) on the AC side continuously measuring the power actually fed to the public electrical grid (30) and transmitting the respective measured power values. The maximum possible feed power of the photovoltaic installation (10) is then calculated using the fraction factor (B) and the continuously measured power values which are correlated therewith over time and the feed fee for the respective photovoltaic installation (10) is determined based on the maximum possible feed power calculated in that way.