Marine Propulsion Arrangement With Bidirectional Electrical Machine
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Solution Overview
Problem
Conventional marine vessel propulsion systems require separate generator sets that are heavy, complex, noisy, and space-consuming, and inefficiently operate at cruising speeds due to engine sizing based on top speed or maximum acceleration, while hybrid systems with clutches can be cumbersome.
Innovation Solution
A propulsion arrangement with an engine and an electrical machine that is selectively operable as a generator or motor, directly coupled to the engine, allowing power supplementation and reduced load on the engine, eliminating the need for a separate generator and motor, and incorporating a bidirectional AC/DC converter for energy management and active damping of engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a separate generator set is used to supply onboard electrical power, then the vessel has sufficient electrical power, but the system becomes heavy, complex, noisy, and occupies significant space
Solution Approach 1:
The patent combines the propulsion engine and electrical power generation function into a single integrated system. The electrical machine is directly coupled to the propulsion engine, allowing it to function as a generator during normal operation to supply onboard electrical power, thereby eliminating the need for a separate generator set and reducing overall system complexity
Solution Approach 2:
The electrical machine serves multiple functions: it acts as a generator during normal propulsion to supply electrical power, and can be controlled to reduce load on the engine during cruising. This multi-functional approach replaces what would traditionally require separate dedicated systems
2Device complexity
If the generator is coupled to the propulsion engine, then the system becomes simpler and lighter, but the generator acts as a load on the engine reducing maximum propulsion
Solution Approach 1:
The patent implements dynamic control of the electrical machine's operation. The control unit monitors engine operating conditions and adjusts the electrical machine's load accordingly - allowing it to draw power during cruising when engine capacity is sufficient, and reducing or eliminating its load when maximum propulsion is required, thus adapting system behavior to real-time conditions
Solution Approach 2:
The control unit changes operational parameters of the electrical machine based on engine load conditions. During cruising at lower engine loads, the electrical machine operates with reduced load or in regenerative mode. When maximum propulsion is needed, the control unit adjusts parameters to minimize or eliminate the electrical machine's load on the engine
3Speed
If the engine is sized for top speed or maximum acceleration, then the vessel achieves maximum performance, but the engine operates inefficiently at cruising speeds
Solution Approach 1:
The control unit continuously monitors engine operating parameters and uses this feedback to adjust the electrical machine's operation. During cruising conditions, the control system detects the engine's operating state and commands the electrical machine to reduce its load or operate in a fuel-efficient mode, thereby optimizing overall system efficiency based on real-time conditions
Solution Approach 2:
The electrical machine and control unit automatically adjust their operation based on engine conditions without external intervention. During cruising, the system self-regulates to reduce electrical load on the engine, and during maximum power demands, it automatically provides supplemental power, enabling the engine to operate more efficiently across different operating conditions
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 the size and weight of the propulsion system, enables quieter and more efficient operation, particularly at anchor, and allows for variable power assistance to the engine, improving fuel efficiency and reducing vibrations.
Implementation Method 1
an electrical machine arranged to supply onboard electrical power for the vessel... the electrical machine when operating as a motor can supplement the power of the engine
Implementation Method 2
the electrical machine is selectively operable as a generator or a motor; wherein the control unit and the electrical machine are arranged such that the electrical machine when operating as a motor can supplement the power of the engine
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A propulsion arrangement for a marine vessel is disclosed. The propulsion arrangement comprises an engine (12, 14) for propelling the vessel and an electrical machine (26, 28) coupled to the engine. The electrical machine is arranged to supply onboard electrical power for the vessel. A control unit (44) controls the electrical machine such that the electrical machine is selectively operable as a generator or a motor. The control unit and the electrical machine are arranged such that the electrical machine when operating as a motor can supplement the power of the engine while the engine is in operation.