Wind Turbine Chopper Control for Post-Fault Power Recovery
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Solution Overview
Problem
Wind turbines face challenges in managing network faults characterized by brief dips in network voltage, as uncontrolled power feeding can lead to new or more severe faults, and existing solutions may not adequately prevent excessive power increases post-fault.
Innovation Solution
A method employing a wind turbine with a full converter concept and chopper circuit to limit power feeding during and after network faults, using a DC voltage intermediate circuit and chopper circuit to control intermediate circuit voltage, ensuring power does not exceed pre-fault levels, and gradually increasing power to prevent overshooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power is fed in at high level immediately after network fault, then power restoration speed is improved, but network stability deteriorates due to possible new faults
Solution Approach 1:
The patent applies dynamics by implementing time-dependent power control strategies. The power feeding is dynamically adjusted based on the timing relative to the network fault: reduced during the fault period and gradually increased after the fault ends. This dynamic adaptation allows the system to restore power efficiently while maintaining network stability through controlled progression rather than abrupt high-level feeding.
Solution Approach 2:
The patent applies preliminary action by reducing power feeding during the network fault period before the fault fully resolves. This preliminary reduction prevents exacerbating the fault condition, and then power is gradually increased after the fault ends, ensuring stable restoration without sudden shocks to the network.
2Reliability
If power feeding is controlled to prevent exceeding pre-fault levels, then network stability is improved, but power restoration efficiency deteriorates
Solution Approach 1:
The patent applies periodic action through a multi-stage power control sequence: first reducing power during the fault period, then systematically increasing it after the fault ends in controlled increments. This periodic modulation of power levels ensures stability by preventing overshooting while maintaining restoration efficiency through structured progression rather than prolonged restriction.
Solution Approach 2:
The system dynamically adjusts power levels based on the fault timeline, transitioning from reduction during the fault to controlled increase after fault resolution. This dynamic approach optimizes the balance between stability and efficiency by adapting power feeding to the actual network state at each moment.
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
Effectively manages power feeding during and after network faults, preventing excessive power increases and ensuring a stable return to normal operating conditions, thereby stabilizing the electrical supply network.
Implementation Method 1
A chopper circuit is likewise connected to the DC voltage intermediate circuit in order to discharge electrical energy from the DC voltage intermediate circuit
Data Source
AI summary
Provided is a method for feeding electrical power into an electrical supply network having a network voltage using a wind turbine having an inverter, which has a DC voltage intermediate circuit having an intermediate circuit voltage and a chopper circuit connected to the intermediate circuit for discharging electrical energy from the intermediate circuit. The method includes feeding electrical power into the network in a normal operation if no network fault has been detected, detecting a fault if the network voltage falls below an undervoltage value, interrupting or reducing the feed if the fault has been detected, and ending the interruption or reduction if the end of a network fault is detected. During the fault and/or from the end of the fault, the fed-in power is limited to a limit, and, to limit the power, the intermediate circuit voltage is limited using the chopper circuit depending upon the limit.