Solar Plant Motor-Generator Grid Stability
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Solution Overview
Problem
Conventional solar systems, classified as type 2 generating units, are unable to fully replace conventional power plants and provide grid stability due to their reliance on electronic inverters and lack of synchronous generators, which are essential for converting renewable energy into grid-compliant alternating or three-phase current.
Innovation Solution
A solar power plant configuration using a reluctance synchronous motor driven by direct current from solar modules, coupled with an induction synchronous generator, an electronic inverter, and a battery buffer connected in parallel, allowing for efficient conversion of direct current to alternating current or three-phase current, with a controller and switchgear for grid connection, ensuring optimal operation and power regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electronic inverters are used to convert direct current from solar modules into alternating current, then the conversion can be achieved, but the system cannot provide grid stability and cannot fully replace conventional power plants
Solution Approach 1:
The patent replaces electronic inverters with a mechanical conversion system consisting of a direct current motor coupled to an alternating current generator. This mechanical substitution enables the system to function as a type 1 generating unit with synchronous generator capability, providing grid stability and system services that electronic inverters cannot deliver.
Solution Approach 2:
The direct current motor serves multiple functions: it acts as a drive for the alternating current generator, provides synchronous generator capability for grid connection, and enables the system to provide system services such as reactive power compensation and voltage control, making the solar power plant universally adaptable to grid requirements.
2Adaptability or versatility
If a direct current motor coupled to an alternating current generator is used, then the system can function as type 1 generating unit, but the device complexity increases
Solution Approach 1:
The patent combines the direct current motor and alternating current generator into a mechanically coupled unit that functions as an integrated conversion system. This merging allows the solar power plant to achieve type 1 generating unit status while managing complexity through unified mechanical coupling rather than separate electronic conversion systems.
3Productivity
If conventional solar systems operate in parallel with the grid, then they can function, but they require multiple times their output in conventional power plant capacity to maintain grid stability
Solution Approach 1:
By replacing electronic inverters with a mechanical motor-generator system that provides synchronous generator capability, the patent enables solar power plants to provide their own grid stability support and system services, eliminating the need for excessive conventional power plant capacity to compensate for stability deficiencies.
4Adaptability or versatility
If electronic inverters are used for direct current to alternating current conversion, then the conversion efficiency can be maintained, but the system lacks synchronous generator capability for grid compliance
Solution Approach 1:
The patent substitutes electronic inversion with mechanical conversion using a direct current motor coupled to an alternating current generator. This mechanical approach inherently provides synchronous generator capability and grid compliance while maintaining conversion efficiency, though it requires different manufacturing considerations compared to electronic inverter systems.
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 configuration enables solar power plants to fully replace conventional power plants, providing efficient energy conversion and grid stability, utilizing high-efficiency reluctance synchronous motors without rare earth materials and requiring minimal maintenance, while ensuring seamless operation and energy storage.
Implementation Method 1
a direct current motor fed by the direct current of the solar modules and with an alternating current generator which is coupled to the shaft of the direct current motor
Implementation Method 2
an alternating current generator which is coupled to the shaft of the direct current motor and which can be connected or connected on the output side directly to a network or to consumers
Implementation Method 3
with a battery buffer storage with which the direct current from the solar modules can be connected
Data Source
Figure 1
AI summary
The invention relates to a solar power plant in which the direct current supplied by solar modules of a solar array is converted into grid-compatible or application-compatible alternating or three-phase current. The direct current drive is a reluctance synchronous motor (5) connected to the output of an electronic inverter (7) and forming a drive unit (15) with it. The alternating or three-phase generator is an induction synchronous generator (6) directly connected to the grid or the loads (4) via an AC switchgear (8), with the direct current supplied by the solar modules (1) being fed into the input of the electronic inverter (7). Furthermore, a battery buffer storage system (2) is connected directly in parallel to the input of the electronic inverter (7).