Wind Turbine Pitch Control for Torque Suppression
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Solution Overview
Problem
Wind turbines experience increased torque and load on devices when utility grid voltage is restored, leading to potential damage due to high currents and torque fluctuations.
Innovation Solution
A wind power generation system with a power generator, converter, inverter, power control unit, and blade control unit that de-actuates and re-actuates operations based on rotor current and DC voltage to maintain synchronous rotation speed, and optionally includes a crowbar circuit for short-circuiting the rotor coil, controlling the pitch angle of wind turbine blades to manage torque and load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the converter and inverter are de-actuated during utility grid voltage drop, then the converter and inverter are protected from overcurrent, but high torque occurs when voltage is restored due to slip frequency
Solution Approach 1:
The blade control unit adjusts the pitch angle in advance before the converter and inverter are re-actuated after a utility grid voltage drop. By controlling the pitch angle to maintain synchronous rotation speed or higher, the system prevents the high torque condition from occurring when the converters are re-actuated, thereby eliminating the need for torque suppression measures while maintaining converter protection
2Force
If the pitch angle is controlled to maintain synchronous rotation speed, then torque increase is suppressed when voltage is restored, but the control system complexity increases
Solution Approach 1:
The patent combines the pitch angle control function with the existing blade control unit that is already part of the wind turbine system. By integrating the torque suppression control into the existing blade control architecture rather than adding a separate control system, the patent achieves torque suppression while minimizing the increase in control system complexity
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
The system effectively suppresses torque increases and reduces device load when utility grid voltage is restored, preventing adverse effects on equipment such as gearboxes by maintaining synchronous rotation speed and adjusting pitch angles accordingly.
Implementation Method 1
a converter configured to convert an output of a rotor of the power generator from a three-phase AC power into a DC power
Implementation Method 2
an inverter configured to convert the DC power outputted from the converter into a three-phase AC power
Implementation Method 3
a power generator; a converter configured to convert an output of a rotor of the power generator
Data Source
AI summary
Provided is a wind power generation system intending to suppress an increase of torque when a voltage in a utility grid is restored, and to reduce a load to devices due to the torque. The blade control unit controls the pitch angle of the wind turbine blades such that a rotation speed of the power generator becomes equal to or greater than a synchronous rotation speed when the power control unit de-actuates the operations of the converter and the inverter, and controls the pitch angle of the wind turbine blades such that the pitch angle matches a target pitch angle that is determined based on one of a wind speed, a rotation speed of the power generator, and a requested output power when the power control unit re-actuates the operations of the converter and the inverter.