Wind Turbine Converter Overvoltage Protection via Chopper Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for responding to overvoltage in utility grids are inadequate, leading to potential damage of wind turbine components and inefficiencies due to disconnection from the grid, as they fail to reliably reduce grid voltage and protect equipment during transient overvoltage events.
Innovation Solution
A method for operating a wind turbine converter that involves determining grid voltage and implementing specific procedures to maintain a safe DC voltage range, including enabling a chopper for energy dissipation and disabling pulse width modulation, to keep the wind turbine connected to the grid and protect components from damage during overvoltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to respond to overvoltage in the utility grid, then the wind turbine is disconnected from the grid to protect components, but this reduces the efficiency of the wind turbine power plant and causes energy loss
Solution Approach 1:
The patent introduces a chopper circuit as an intermediary device between the converter and the grid. This chopper acts as a mediator that absorbs and dissipates excess energy during overvoltage events, protecting the converter components while allowing the wind turbine to remain connected to the grid and continue generating power.
Solution Approach 2:
The patent extracts the energy dissipation function from the main converter circuit and places it in a separate chopper circuit. This allows the overvoltage protection mechanism to operate independently without affecting the main power conversion and transmission function, enabling the turbine to stay connected during overvoltage events.
2Productivity
If the wind turbine remains connected to the grid during overvoltage events, then energy supply continuity is maintained, but components such as filters and converters may be damaged by extremely high voltages
Solution Approach 1:
The patent implements a chopper circuit that is pre-configured and ready to activate during overvoltage events. This cushioning mechanism is in place before the overvoltage occurs, providing immediate protection when needed without requiring disconnection of the wind turbine from the grid.
Solution Approach 2:
The patent converts the harmful overvoltage energy into a useful function by using the chopper circuit to deliberately dissipate the excess energy through controlled resistance. The harmful high voltage energy is transformed into heat in the chopper resistor, protecting other components while allowing the turbine to remain connected.
3Reliability
If reactive power is supplied to lower grid voltage, then the grid voltage may be reduced, but this method is not reliable in all situations and does not consistently protect wind turbine components
Solution Approach 1:
The patent changes the control parameter from reactive power injection to active power dissipation through the chopper circuit. By controlling the chopper switch duty cycle and resistance, the system directly manages the DC link voltage and absorbs excess energy, providing more reliable and adaptable protection across different overvoltage scenarios.
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
The solution effectively reduces grid voltage, prevents component damage, and maintains wind turbine connectivity during overvoltage events, enhancing operational reliability and efficiency by allowing the turbine to remain connected and continue energy supply.
Implementation Method 1
enabling a chopper for energy dissipation
Data Source
AI summary
A method of operating a converter of a wind turbine for providing electric energy to a utility grid includes determining a grid voltage. If the grid voltage is between a nominal voltage and a first voltage threshold, i.e. higher than the nominal voltage, a normal procedure for lowering the grid voltage is performed. If the grid voltage is above the first voltage threshold, another procedure for keeping the wind turbine connected is performed, wherein the other procedure is different from the normal procedure. Further a corresponding arrangement is described.