Marine Propulsion Controller Limits Engine Output to Prevent Induced Voltage
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Solution Overview
Problem
In marine propulsion systems with multiple propulsion devices, induced voltage generated by entrained rotation of electric motors can damage electric circuits and motors when one device is powered off, leading to unprotected operation and potential overheating.
Innovation Solution
Implementing controllers in each marine propulsion device to limit the output of engines or electric motors when they are not driven, ensuring communication between devices to prevent excessive rotational speed and induced voltage, thereby protecting the electric circuits and motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple marine propulsion devices are mounted to a watercraft, then propulsion capability and versatility are improved, but the risk of induced voltage damage to electric circuits and motors increases when one device is powered off
Solution Approach 1:
The controller executes a limitation control routine before damage can occur. When a propulsion device is powered off, the controller proactively limits the output of the engine or electric motor to prevent excessive rotational speed that would generate harmful induced voltage, thereby protecting the electric circuit and motor in advance
Solution Approach 2:
The controller continuously monitors the operational state of all propulsion devices and adjusts the output accordingly. When a device is detected to be powered off, the controller feedback-loop activates the limitation control routine to prevent induced voltage damage, creating a closed-loop protection system
2Use of energy by moving object
If the electric motor is not supplied with electric power, then energy consumption is reduced, but the electric motor and electric circuit become uncontrolled and vulnerable to induced voltage
Solution Approach 1:
The limitation control routine operates autonomously based on the power supply state detection. When a propulsion device is detected to be powered off, the controller automatically executes the limitation routine without requiring external intervention, enabling the system to self-protect against induced voltage damage while maintaining energy efficiency
3Productivity
If the output of the engine is not limited when the electric motor is not driven, then propulsion efficiency is maintained, but excessive rotational speed generates induced voltage that damages the electric circuit
Solution Approach 1:
The output limitation is dynamic and conditional rather than static. The controller adjusts the engine output limitation based on real-time detection of the electric motor's power supply state, allowing full propulsion efficiency when the motor is powered and activating protection only when the motor is powered off, thus balancing efficiency and safety
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
Prevents damage from induced voltage by limiting propulsion speed and rotational speed, effectively protecting electric circuits and motors from overheating and ensuring safe operation.
Implementation Method 1
induced voltage is generated by an electric motor when entrained rotation of the electric motor occurs through a propeller rotated by driving of the two marine propulsion devices
Data Source
AI summary
A marine propulsion system includes a first marine propulsion device and a second marine propulsion device. The first marine propulsion device includes an engine, a first propeller shaft to receive a driving force from the engine, and a first controller configured or programmed to control the engine. The second marine propulsion device includes an electric motor, a second propeller shaft to receive a driving force from the electric motor, an electric circuit connected to the electric motor to drive the electric motor, and a second controller configured or programmed to control the electric motor. The first controller is configured or programmed to put a limitation on an output of the engine when the electric motor is not being driven.