Triple-Fed Frequency Converter for Renewable Energy Grid Stability
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Solution Overview
Problem
Existing systems for exploiting wind and solar energy through pumped storage hydroelectricity face inefficiencies due to intermittent and fluctuating electrical energy output, requiring reactive power from the grid, leading to instabilities and operational restrictions, especially in non-connected islands, and limiting the use of renewable energy for powering electric pumps.
Innovation Solution
A system integrating wind farms, photovoltaic power stations, and a hydroelectric pumped storage power station with AC variable speed drives, direct torque control, and triple-fed frequency converters synchronizes energy from wind, solar, and stored sources, allowing asynchronous operation of electric motor-driven pumps and reducing grid instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wind turbines with asynchronous generators are used to convert wind energy to electrical energy, then wind energy can be exploited, but the electrical energy output is intermittent and fluctuating with low quality, requiring reactive power from the grid and causing instabilities
Solution Approach 1:
The patent introduces an AC variable speed drive system with triple-fed frequency converters as an intermediary between the wind turbines and the grid. This mediator converts the intermittent and fluctuating electrical energy from wind turbines into stable, high-quality electrical energy, eliminating the need for reactive power from the grid and preventing instabilities in non-connected islands.
Solution Approach 2:
The patent changes the parameters of electrical energy by using AC variable speed drives and frequency converters to transform the intermittent and fluctuating output from wind turbines into stable frequency and voltage parameters, thereby improving electrical energy quality and reliability.
2Reliability
If grid operators impose restrictions on electrical power supplied by wind farms due to low quality electricity, then grid stability is maintained, but subsets of wind turbines are out of operation reducing productivity
Solution Approach 1:
The AC variable speed drive system acts as a mediator that ensures high-quality electrical energy output from wind turbines, allowing wind farms to operate at full capacity without imposing restrictions on grid operators, thus maintaining both grid stability and maximum productivity.
Solution Approach 2:
The patent employs control systems with feedback mechanisms that monitor electrical energy quality and adjust the operation of wind turbines and frequency converters in real-time, ensuring that grid stability requirements are met while maximizing the operational capacity of wind turbines.
3Use of energy by moving object
If intermittent and fluctuating electrical energy from wind turbines and photovoltaic cells is used to power electric driven pumps, then renewable energy exploitation is achieved, but the efficiency is low and the pumps cannot operate at optimal performance
Solution Approach 1:
The AC variable speed drive system serves as an intermediary between renewable energy sources and electric pumps, converting intermittent and fluctuating electrical energy into stable, high-quality power that enables pumps to operate at optimal efficiency while fully utilizing renewable energy resources.
Solution Approach 2:
The patent uses dynamic speed control of electric pumps through AC variable speed drives, allowing the pumps to adapt their operating speed to match the available renewable energy input while maintaining optimal efficiency, thereby resolving the contradiction between renewable energy utilization and pump performance.
4Power
If pumped storage is used to store electrical energy from thermal power stations during low demand, then peak load demands can be met, but the system does not efficiently exploit wind and solar energy
Solution Approach 1:
The patent makes the pumped storage system universal by enabling it to store electrical energy from multiple sources including thermal power stations, wind turbines, and photovoltaic cells. The AC variable speed drive system allows the pumped storage to efficiently handle variable renewable energy input while maintaining the capability to meet peak load demands.
Solution Approach 2:
The patent ensures continuous useful action by using pumped storage to balance the intermittent nature of renewable energy sources, storing excess energy when available and releasing it when needed, thereby maintaining continuous power supply and enabling efficient exploitation of wind and solar energy alongside traditional thermal power.
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 system enhances the efficient management and storage of renewable energy, stabilizes grid operations, reduces mechanical stress on equipment, and enables peak efficiency of thermal power stations by leveling energy fluctuations, ensuring reliable operation of wind farms and reducing fossil fuel dependency.
Implementation Method 1
the conversion of wind energy to electrical energy is carried out with the use of wind turbines
Implementation Method 2
the conversion of solar energy to electrical energy is carried out with the use photovoltaic cells
Implementation Method 3
the conversion of electrical energy to potential energy by means of pumping water from a low level to a higher level
Implementation Method 4
the conversion of stored potential energy to hydraulic energy and then to electrical energy
Data Source
Figure 1
Figure 2
AI summary
A system of production and management of electrical energy from renewable sources of energy, particularly from the synergetic exploitation of wind and solar energy through pumped storage hydroelectricity within a manmade water system, with the use of power electronics, including at least one hydroelectric pumped storage power station (5) which has: at least one hydroelectric turbine (9, 7), at least one electric motor driven pump (8, 6), at least one triple-fed frequency converter (FVC1), and at least one AC variable speed drive (DRIVE 2) which is fed from the output of the frequency converter (FVC1) and transmits electric power to the electric motor (8) of the electric motor driven pump. The triple-fed frequency converter (FVC1) has a first feed with electrical energy from the generator (9) of the hydroelectric turbine, a second feed from at least one wind farm (11) and a third feed from at least one photovoltaic power station (12). The leveling of the intermittent and fluctuating electrical energy from the wind farm (11) and from the photovoltaic power station (12) is realized by controlling the flow of electrical energy from the generator (9) of the hydroelectric turbine to the first feed of the triple-fed frequency converter (FVC1).