Frequency Converter Coupling Device for Offshore Power Transmission
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Solution Overview
Problem
Existing systems for transmitting electrical power from a wind farm to an AC voltage network via a DC voltage connection are inefficient and costly, particularly when arranged offshore, due to the need for transformers and inductances to adapt the AC component for energy supply during weak wind periods.
Innovation Solution
Incorporating a frequency converter in the coupling device to adapt the frequency, amplitude, and phase position of the AC component, eliminating the need for transformers and inductances, and using a modular multi-level converter to ensure reliable energy transmission to the AC voltage network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer and inductance are used to decouple the AC component in the known system, then the AC component can be decoupled and fed into the AC voltage network, but the space requirement and cost increase significantly
Solution Approach 1:
The patent changes the fundamental parameters of the coupling device by replacing the transformer-inductance configuration with a frequency converter. This parameter change enables the system to adapt the frequency, amplitude, and phase of the AC component electronically, eliminating the need for bulky magnetic components while maintaining the decoupling function and energy supply reliability.
Solution Approach 2:
The patent substitutes the mechanical/electromagnetic system (transformer and inductance) with an electronic control system (frequency converter). The frequency converter uses power electronic switches and control circuits to achieve the same decoupling and adaptation functions without requiring large magnetic components, thereby reducing space requirements while maintaining reliability.
2Reliability
If a transformer and inductance are used to decouple the AC component in the known system, then the AC component can be decoupled and fed into the AC voltage network, but the cost increases significantly
Solution Approach 1:
The patent changes the fundamental parameters of the coupling device by replacing the transformer-inductance configuration with a frequency converter. This parameter change enables the system to adapt the frequency, amplitude, and phase of the AC component electronically, eliminating the need for bulky magnetic components while maintaining the decoupling function and energy supply reliability.
Solution Approach 2:
The patent substitutes the mechanical/electromagnetic system (transformer and inductance) with an electronic control system (frequency converter). The frequency converter uses power electronic switches and control circuits to achieve the same decoupling and adaptation functions without requiring large magnetic components, thereby reducing space requirements while maintaining reliability.
3Reliability
If the first AC voltage network is supplied during weak wind periods using the known system, then energy supply is ensured, but the system requires complex components with large space requirements
Solution Approach 1:
The patent changes the fundamental parameters of the coupling device by replacing the transformer-inductance configuration with a frequency converter. This parameter change enables the system to adapt the frequency, amplitude, and phase of the AC component electronically, eliminating the need for bulky magnetic components while maintaining the decoupling function and energy supply reliability.
Solution Approach 2:
The frequency converter performs multiple functions within a single integrated device: it decouples the AC component from the DC voltage connection, adapts the frequency to match the AC voltage network requirements, adjusts the amplitude to the appropriate level, and controls the phase position. This multi-functionality reduces device complexity compared to the separate transformer and inductance components required in the known system.
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 solution reduces space and cost requirements, enabling reliable energy transmission to the AC voltage network even under stand-alone grid conditions, with a significant cost advantage when deployed offshore.
Implementation Method 1
the coupling device includes a frequency converter for converting a frequency, amplitude and phase position of the AC component
Data Source
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AI summary
The invention relates to a system (1) for transmitting electrical power comprising a unidirectional rectifier (2) that can be connected to a first AC voltage network (3), a converter system (7) that is connected to the unidirectional rectifier via a DC voltage connection (4), wherein electrical power of an AC voltage source can be converted into transmission power by means of the converter system, which transmission power has a DC portion and an AC portion, and can be fed into the DC voltage connection; also comprising a coupling device (9) for decoupling the AC portion of the transmission power from the DC voltage connection and for feeding the AC portion into the first AC voltage network. The invention is characterised in that the coupling device (9) comprises a frequency converter (10) for transforming a frequency, amplitude and phase position of the AC portion. The invention also relates to a method for transmitting electrical power using the system according to the invention. The same arrangement can also be produced for an inverter in a symmetrically mirrored form.