HVDC Network Bridge Controller for Autonomous Wind Turbine Coordination
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Solution Overview
Problem
There is a need for a control procedure that allows wind turbines in a wind park to operate autonomously and coordinate power production without relying on communication with adjacent turbines, specifically when connected to the utility grid solely via an HVDC power transmission system, addressing challenges such as power flow control, voltage management, and reactive power balancing.
Innovation Solution
The control method determines control signals for the network bridge of a power converter, enabling comprehensive control of the power generating and forwarding system, including wind turbines, AC systems, and HVDC transmission, allowing autonomous operation and coordination of power production without external communication, using local measurements and feedback signals to manage active and reactive power flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wind turbines are connected to the utility grid solely via HVDC power transmission system, then power transmission efficiency is improved over long distances, but control complexity increases due to the need for autonomous operation and coordination without communication
Solution Approach 1:
Each wind turbine is equipped with autonomous control capability that allows it to independently determine its power output and voltage phase angle based on local measurements and system conditions, eliminating the need for centralized control or communication between turbines while maintaining coordinated operation through the common DC link voltage
2Reliability
If autonomous operation without communication is implemented, then operational reliability is improved, but the ability to coordinate power production and balance reactive power becomes more difficult
Solution Approach 1:
The control system continuously monitors the common DC link voltage and uses this feedback to autonomously adjust each turbine's power output and voltage phase angle, enabling automatic coordination and reactive power balancing without communication while maintaining operational reliability
Solution Approach 2:
All wind turbines connect to a common DC link that maintains a uniform voltage level, creating an equipotential system that naturally coordinates power flow and enables automatic reactive power balancing through the shared voltage reference without requiring communication between turbines
3Manufacturing precision
If comprehensive control of network bridge is implemented, then power and voltage control precision is improved, but device complexity increases
Solution Approach 1:
The comprehensive control function is segmented into modular components: power control based on active power reference, voltage control based on DC link voltage, and phase angle control for reactive power management. Each module handles a specific aspect of control, achieving high precision while keeping individual controller structures manageable and organized
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 approach enables efficient and reliable power management, allowing wind turbines to operate autonomously and coordinate power production effectively, stabilizing frequency and balancing reactive power, thus optimizing energy capture and reducing operational complexity.
Implementation Method 1
a mechanical drive train comprising a rotor with several rotor blades drives an electric generator... The resulting alternating current (AC) frequency that is developed at stator terminals of the electric generator is directly proportional to the speed of rotation of the rotor
Implementation Method 2
An adaptation of the variable voltage and frequency of the electric generator to a nominally fixed voltage and frequency of a power grid is typically achieved by a power converter
Implementation Method 3
By contrast to an AC power connection it is however also possible to transfer the electric power being generated in particular by a plurality of wind turbines being assigned to a wind park to a power or utility grid via a so called High Voltage Direct Current (HVDC) power connection
Data Source
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AI summary
A method for controlling the operation of a wind turbine (120) is described. The method comprises (a) receiving an active power reference signal (P*conv, PrefWT) and an active power feedback signal (Pfb); (b) determining, based on the active power reference signal (P*conv, PrefWT) and the active power feedback signal (Pfb), a first voltage control signal (Vd) and a power controller frequency signal (ωPC); (c) determining, based on the power controller frequency signal (ωPC), a second voltage control signal (Vq); (d) determining, based on the frequency reference signal (ωref), a frequency controller frequency signal (ωFC); (e) determining, based on the power controller frequency signal (ωPC) and the frequency controller frequency signal (ωFC), an actual angle signal (θ0) being indicative for an actual angle of a rotating dq reference frame; and (f) controlling the operation of a power converter (240) of the wind turbine (120)based on the first voltage control signal (Vd), the second voltage control signal (Vq), and the actual angle signal (θ0). It is further described a network bridge controller, a wind turbine, a power generating and forwarding system, and a computer program which are all capable of carrying out or controlling the described control method.