Wind Turbine Converter Frequency Control for Stand-Alone Start-Up
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Solution Overview
Problem
Conventional wind turbines struggle to maintain operation and start-up during grid disconnection due to unmet auxiliary power demands, especially in offshore farms, leading to potential damage and inefficiency without external generators like diesel units.
Innovation Solution
A method and arrangement using a wind turbine converter and UPS to manage auxiliary power, where the UPS draws power from the converter, modulating frequency to balance power, enabling standalone operation and start-up, eliminating the need for external generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wind turbine is disconnected from the utility grid, then operational independence and safety are improved, but auxiliary power supply becomes insufficient leading to potential damage
Solution Approach 1:
The wind turbine serves itself by using its own generator output, converted through the wind turbine converter, to supply auxiliary power during grid disconnection. The system independently manages its own power needs without external diesel generators or additional equipment.
Solution Approach 2:
The wind turbine converter is designed to perform multiple functions: it converts generator output for grid connection during normal operation, and alternatively converts generator output to supply auxiliary loads during grid disconnection. This multi-functionality eliminates the need for separate auxiliary power systems.
2Adaptability or versatility
If conventional wind turbines operate during grid disconnection, then operational flexibility is improved, but device complexity increases due to requirement of external generators
Solution Approach 1:
The invention extracts and removes the need for external auxiliary power generators (such as diesel generators) from the system. By utilizing the wind turbine's own power conversion capability, the system eliminates complex external equipment while maintaining operational flexibility during grid disconnection.
3Power
If the wind turbine converter controls power output to meet UPS demands, then power balance is improved, but control precision requirements increase
Solution Approach 1:
The wind turbine converter controller continuously monitors the power output from the generator and the power demands of the UPS, adjusting the conversion ratio and output characteristics in real-time to maintain power balance. This feedback control ensures stable operation despite varying wind conditions and load requirements.
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
Ensures reliable and safe wind turbine operation during grid disconnection by maintaining essential functions and facilitating start-up, reducing reliance on external equipment and enhancing operational flexibility.
Implementation Method 1
a generator (101) which, upon rotation of a rotor (102), produces electrical energy
Implementation Method 2
a wind turbine converter (104) comprising a grid side converter portion (217) and a generator side converter portion (216)
Implementation Method 3
a UPS (105) comprising an accumulator (239)
Data Source
AI summary
A method of operating a wind turbine during disconnection from a utility grid includes a generator, a wind turbine converter, in particular including a grid side converter portion connectable to the utility grid, a DC link, a generator side converter portion, and a UPS, the method including: allowing the UPS to draw, according to an UPS active power reference, active power from the wind turbine converter (104); controlling the wind turbine converter by a converter power reference to meet the UPS active power reference. Controlling the wind turbine converter by the converter power reference includes modulating a frequency of the converter terminal voltage in dependence of the converter power operating point, in particular the converter power reference.