Network Bridge Controller for Wind Turbine HVDC-AC Power Management
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Solution Overview
Problem
Current wind turbine control methods struggle to efficiently manage power transmission between offshore wind parks and onshore grids via HVDC systems, particularly in scenarios where bi-directional power flow is required, due to complex and heavy AC-DC converters and passive rectifiers that limit operational flexibility and reliability.
Innovation Solution
A control method for wind turbines that utilizes a network bridge controller to manage power flow through both HVDC and AC auxiliary systems, determining control signals for voltage, frequency, and phase angle to enable autonomous operation and coordinated power balance without external communication, using a combination of power controllers, theta integrators, and umbilical power controllers to stabilize frequency and optimize power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If passive rectifiers and heavy AC-DC converters are used for HVDC power transmission, then power transmission capability is achieved, but device complexity and operational flexibility deteriorate
Solution Approach 1:
The patent replaces traditional passive rectifiers and heavy AC-DC converters with a network bridge controller that uses control algorithms to manage power flow. The network bridge uses PWM-controlled semiconductor switches instead of passive rectification, eliminating the need for bulky transformers and complex rectifier circuits while maintaining full bidirectional power transmission capability.
Solution Approach 2:
The invention changes the operating parameters of the power conversion system by using active PWM control of semiconductor switches in the network bridge, allowing dynamic adjustment of power flow direction and magnitude. This replaces fixed-parameter passive rectifiers with variable-parameter active conversion, enabling flexible operation in both rectifier and inverter modes without hardware changes.
2Power
If traditional AC-DC converters are used for power conversion, then power transmission is achieved, but operational flexibility and reliability deteriorate due to limited bi-directional capability
Solution Approach 1:
The network bridge controller dynamically adjusts the switching states of semiconductor devices based on real-time power flow requirements. The system can seamlessly transition between rectifier mode (AC to DC) and inverter mode (DC to AC) by changing control signals, enabling bidirectional power transmission and flexible operational modes without mechanical moving parts or hardware reconfiguration.
Solution Approach 2:
The same network bridge circuitry performs multiple functions: it operates as a rectifier during normal wind power generation, as an inverter during grid support operations, and can provide reactive power compensation. This multi-functional capability eliminates the need for separate devices for different operational modes, enhancing both flexibility and reliability.
3Power
If complex control systems with external communication are used for coordinated power management, then power balance is achieved, but system complexity and communication dependency increase
Solution Approach 1:
The network bridge controller implements autonomous control by locally measuring power flow, voltage, and frequency parameters and automatically adjusting its switching commands to maintain power balance. The controller uses embedded algorithms to detect operational mode changes and coordinate with the HVDC system without requiring external communication infrastructure, making the system self-sufficient and communication-independent.
Solution Approach 2:
The control system continuously monitors local electrical parameters (voltage, current, frequency, power flow) and uses this feedback to dynamically adjust the switching states of the network bridge. This closed-loop control enables precise power management and coordination between AC and HVDC systems based on real-time system conditions, eliminating the need for complex external communication protocols.
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
Enables efficient, autonomous, and coordinated power management between wind turbines and the grid, reducing operational complexity and enhancing reliability by allowing bi-directional power flow and independent operation of wind turbines, thus stabilizing frequency and optimizing power transfer in HVDC and AC systems.
Implementation Method 1
a power converter typically further comprises a network bridge which converts the DC power of the DC link to an AC power output
Implementation Method 2
The generator bridge can have any suitable topology with a series of semiconductor power switching devices fully controlled and regulated using a pulse width modulation (PWM) strategy
Implementation Method 3
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
Data Source
AI summary
A method is provided for controlling the operation of a wind turbine includes (a) receiving an active power reference signal; (b) determining, based on the active power reference signal and an active power feedback signal, a first voltage control signal and a power controller frequency signal; (c) receiving a power reference signal; (d) determining, based on the power reference signal and the power feedback signal, a power offset frequency signal; (e) determining, based on the power controller frequency signal, a second voltage control signal; (f) determining, based on the power offset frequency signal, an angle signal indicative for an actual angle of a rotating dq reference frame; and (g) controlling the operation of a power converter based on the first voltage control signal, the second voltage control signal, and the angle signal.