Cycloidal Propulsion Drive With Shared DC-Link Regeneration
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Solution Overview
Problem
Existing electrically driven cycloidal marine propulsion units lack efficiency and reliability, particularly in applications requiring high maneuverability and power management, as they do not effectively utilize regenerative power and often require unnecessary braking systems.
Innovation Solution
A drive arrangement for cycloidal marine propulsion units featuring electric motors coupled to power converters sharing a common intermediate DC-link, allowing regenerative power to be recovered and reused within the system, reducing the need for braking choppers and resistors, and providing redundancy through multiple DC-links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative power is recovered and fed to other components coupled to the DC-link, then energy efficiency is improved, but system complexity increases
Solution Approach 1:
Multiple power converters (blade drive converters and stern drive converter) share a common intermediate DC-link, merging their power processing functions. This allows regenerative power from blade motors to be automatically fed to other components without requiring separate braking systems for each converter, improving energy efficiency while the shared architecture limits the increase in overall system complexity
Solution Approach 2:
The common DC-link serves multiple functions: it provides power to multiple converters, accepts regenerative power from any connected motor, and enables bidirectional power flow between different drive components. This multi-functionality allows a single DC-link structure to handle both propulsion power distribution and regenerative energy recovery, improving efficiency without proportionally increasing complexity
2Device complexity
If braking choppers and resistors are eliminated through regenerative power recovery, then device complexity is reduced, but reliability may worsen
Solution Approach 1:
Instead of dissipating regenerative power as heat through braking resistors (harmful energy loss), the system converts this previously wasted energy into a useful resource by feeding it back to the common DC-link where it can power other components. This transforms the harmful energy dissipation into a beneficial power recovery mechanism, reducing the need for braking choppers and resistors while maintaining system reliability through redundant power paths
Solution Approach 2:
The system recovers energy that would otherwise be discarded during motor deceleration. Instead of allowing regenerative power to be lost through traditional braking resistors, the power converters detect and capture this regenerative energy, redirecting it to the common DC-link for reuse by other drive components, thereby eliminating the need for separate braking dissipation systems
3Productivity
If multiple power converters share a common intermediate DC-link, then energy efficiency is improved through regenerative power recovery, but the device complexity increases
Solution Approach 1:
The power conversion system merges multiple independent converter architectures into a unified system sharing a common intermediate DC-link. This consolidation allows blade drive converters and stern drive converter to interact through the shared DC-link, enabling regenerative power from any motor to benefit the entire propulsion system, thereby improving overall propulsion efficiency while the modular converter design keeps complexity manageable
Solution Approach 2:
The power conversion system is segmented into independent modular converters (blade drive converters and stern drive converter) that can be individually controlled and maintained. Each converter operates semi-independently but connects through the common DC-link, allowing the system to achieve high propulsion efficiency through coordinated operation while the modular segmentation prevents complexity from becoming unmanageable by enabling independent testing, replacement, and optimization of individual converter modules
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 configuration enhances the efficiency of cycloidal marine propulsion units by utilizing regenerative power, reducing the need for braking systems, and increasing the reliability of the propulsion system, making it suitable for a broader range of marine vessel applications.
Implementation Method 1
at least two electrical blade motors (3a) each associated to a respective blade (3) for pivoting thereof
Implementation Method 2
Each blade motor (3a) is operationally coupled to a respective blade drive (3b) having a power converter fed from a common intermediate DC-link (4)
Data Source
AI summary
A drive arrangement for a cycloidal marine propulsion unit including at least two electrical blade motors each associated to a respective blade for pivoting thereof, each blade motor being operationally coupled to a respective blade drive for actuating the corresponding blade motor. The at least two blade drives each include a respective blade drive power converter operationally coupled to a first common intermediate DC-link, wherein the at least two blade drives being configured to feed power from the first common intermediate DC-link to their respective blade motors, and to feed regenerative power from their respective blade motors to the first common intermediate DC-link. The disclosure also concerns a marine propulsion unit having such a drive arrangement, and a method of operating such a drive arrangement.