Wind Turbine Actuator Control With DC Link Boost Support
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Solution Overview
Problem
Existing wind turbine control systems face challenges in efficiently managing power and voltage demands during extreme weather conditions or grid faults, particularly in maintaining optimal actuator performance without adding additional components.
Innovation Solution
A method and system that utilizes a DC link intermediate circuit powered by a first converter connected to a supply grid, with a second converter activated to boost voltage and/or power from an energy storage unit when demands exceed the first converter's capacity, allowing parallel operation to enhance actuator performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the first converter is used to provide voltage and power to the DC link intermediate circuit during normal operation, then the system operates efficiently with grid power, but during extreme weather conditions or grid faults, the voltage and/or power output becomes insufficient to meet actuator demands
Solution Approach 1:
The energy storage unit is pre-charged during normal operation when grid power is sufficient, so that when extreme conditions occur, the stored energy is already available to immediately support the actuator without interruption. This preliminary energy accumulation resolves the contradiction by ensuring reliability is maintained through advance preparation.
Solution Approach 2:
The system dynamically changes the operating parameters of the second converter based on conditions. During normal operation, the second converter operates in a standby or charging mode. During extreme conditions, it switches to boost mode, changing its voltage and power output parameters to supplement the first converter and meet actuator demands, thus resolving the power insufficiency while maintaining reliability.
2Power
If the second converter is activated in boost mode to increase voltage and power output during critical conditions, then actuator performance is enhanced, but system complexity increases due to parallel converter operation
Solution Approach 1:
The second converter is designed with multi-functionality: during normal operation it can charge the energy storage unit or operate in standby, and during extreme conditions it switches to boost mode to supplement power output. This universal design allows a single component to serve multiple purposes, enhancing power capability without proportionally increasing system complexity.
Solution Approach 2:
The energy storage unit acts as an intermediary between the grid and the actuator. It buffers the power fluctuations and allows the second converter to operate more efficiently by providing a stable energy reservoir. This intermediary component simplifies the control complexity of the parallel converter system by decoupling the two converters through the energy storage interface.
3Force
If the second converter operates in boost mode to meet high power demands, then the actuator can overcome field weakening effects and maintain torque output, but the energy storage unit experiences increased discharge rates
Solution Approach 1:
The boost mode operation is designed as a periodic or transient action rather than continuous. The second converter activates in boost mode only during the specific periods when high torque is needed (such as during gust mitigation or grid faults), and returns to normal operation when conditions stabilize. This periodic activation allows the energy storage unit to discharge at high rates only when necessary, with sufficient time for recharging during normal operation.
Solution Approach 2:
The system dynamically adjusts the operating mode of the second converter based on real-time conditions. The controller monitors actuator torque demands, grid conditions, and energy storage state, dynamically switching between standby/charging mode and boost mode. This dynamic operation optimizes the balance between torque output and energy discharge rate, ensuring high torque is available when needed while managing the energy storage unit's discharge capacity.
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
Enhances actuator performance by overcoming field weakening effects and increasing torque and power output during critical conditions, ensuring reliable operation without requiring more complex converters.
Implementation Method 1
triggering a boost mode of a second converter configured to be connected between the DC link intermediate circuit and an energy storage unit to at least one of: boost the voltage at the DC link intermediate circuit to a second voltage, the second voltage being higher than the first voltage
Implementation Method 2
boost the power supplied to the electro-mechanical actuator via the DC link intermediate circuit to a second power, the second power being higher than the first power
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present disclosure relates to a method for controlling an electro-mechanical actuator (250) of a wind turbine (100), in particular a servo motor (252) of a yaw or a pitch system of the wind turbine (100). The electro-mechanical actuator (250) is configured to be powered from a DC link intermediate circuit (220). The method comprises: determining whether at least one of a voltage demand and a power demand for operating the electro-mechanical actuator (220) at a specific operating point can be met by an output of a first converter (212), the first converter (212) being connected to a supply grid on its input side and configured to provide at least one of a first voltage and a first power to the DC link intermediate circuit (220); and, if at least one of the voltage demand and the power demand cannot be met by the output of the first converter (212), triggering a boost mode of a second converter (214) configured to be connected between the DC link intermediate circuit (220) and an energy storage unit (240). The boost mode is triggered to at least one of: boost the voltage at the DC link intermediate circuit (220) to a second voltage, the second voltage being higher than the first voltage; and boost the power supply to the electro-mechanical actuator (250) via the DC link intermediate circuit (220) to a second power, the second power being higher than the first power. The disclosure further relates to an electro-mechanical actuation system (200) and a wind turbine (100).