Converter Hysteresis Control with Deadtime for Oscillation Suppression
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Solution Overview
Problem
Power converters in wind turbines experience unnecessary switching actions due to vibration effects, leading to high losses, which existing control methods fail to adequately address.
Innovation Solution
A method for controlling inverters in wind turbines using a tolerance band with adjustable dead time to suppress non-system relevant switching actions, ensuring the current remains within defined limits, thereby minimizing unnecessary switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional tolerance band control is used without deadtime, then the current is quickly regulated within the band limits, but unnecessary switching actions occur due to vibration effects
Solution Approach 1:
The control method introduces a deadtime period that is activated in advance when the current leaves the tolerance band. This preliminary action prevents immediate switching responses to transient vibrations, allowing the system to anticipate and avoid unnecessary switching actions while maintaining effective current regulation.
2Loss of energy
If switching actions are suppressed to reduce losses, then energy efficiency improves, but current regulation quality may deteriorate
Solution Approach 1:
The control method dynamically adjusts the switching behavior by implementing a deadtime period that is activated conditionally when the current leaves the tolerance band. This dynamic approach allows the system to suppress unnecessary switching during transient vibrations while maintaining precise current regulation when needed, achieving both energy efficiency and regulation quality.
3Loss of energy
If deadtime is introduced to suppress oscillation-induced switching, then unnecessary switching actions are reduced, but response time to actual current deviations increases
Solution Approach 1:
The control method uses feedback to monitor whether the current actually leaves the tolerance band before activating the deadtime suppression. This feedback mechanism ensures that deadtime is only introduced when necessary, preventing unnecessary delays in response to genuine current deviations while still suppressing oscillation-induced switching actions.
Data Source
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AI summary
The present invention relates to a method for controlling a power converter, in particular an inverter, preferably a converter, comprising an inverter, in particular of a wind turbine, comprising the steps of: specifying a tolerance band with at least one band limit for the power converter, in particular for a switching element of the power converter, specifying a delay comprising a dead time, in particular for the switching element of the power converter, detecting an actual current of the power converter, in particular an actual current of the switching element of the power converter, comparing the detected actual current with the band limit to detect a departure from the tolerance band, switching the power converter, in particular the switching element of the power converter, to come within the tolerance band, suppressing further, in particular non-system-relevant, switching operations of the power converter, in particular of the switching element, for the specified dead time.