Submarine Drive Motor Switching Control for Efficiency

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Solution Overview

Problem

Submarine propulsion systems struggle to maintain efficiency and acoustic noise optimization across different operating conditions, particularly when transitioning between surface and underwater travel, due to the steeper propeller curve for surface travel leading to higher currents and inefficient switching points.

Innovation Solution

The control device selects a different operating point for switchover based on the travel status, using threshold values for speed and permissible nominal current derived from propeller curves, allowing the motor to remain in the efficiency and noise-optimized first operating range for longer during underwater travel without major structural changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single switching operating point is used for both surface and underwater travel, then the control system is simple, but the motor cannot maintain efficiency and acoustic noise optimization across different operating conditions

Engineering Contradiction:
Improveadaptability to different travel conditionsVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the switching operating point adaptive rather than fixed. The control device dynamically adjusts the switching threshold based on the submarine's travel condition (surface or underwater), allowing the motor to operate in the optimal first operating range for each condition. This resolves the contradiction by enabling adaptability through dynamic parameter adjustment without requiring complex structural changes to the motor itself.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters by selecting different switching thresholds for surface and underwater travel. The control device determines separate operating points based on propeller curves specific to each travel condition, allowing the motor to remain in the efficiency-optimized first operating range longer during underwater travel. This parameter adjustment resolves the contradiction by adapting control parameters to match different operational environments.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the switching operating point is derived from the steeper surface travel propeller curve, then surface travel performance is optimized, but underwater travel efficiency and noise optimization are compromised

Engineering Contradiction:
Improvesurface travel performanceVSAvoidunderwater travel energy efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies local quality by optimizing the switching operating point for each specific travel condition separately. Instead of using a single universal threshold, the control device determines distinct operating points: one based on the surface travel propeller curve and another based on the underwater travel propeller curve. This allows each travel condition to benefit from its own optimized parameters, resolving the contradiction between surface performance and underwater efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the switching parameter (operating point) based on the travel condition. The control device selects different threshold values for speed or current based on whether the submarine is traveling on the surface or underwater, matching each condition's propeller curve characteristics. This parameter adaptation ensures optimal energy efficiency for underwater travel while maintaining surface performance, resolving the contradiction between the two travel modes.

Inventive Principle:
Principle #35Parameter changes

3Power

If the motor operates in the second operating range for higher speeds, then drive power is increased, but efficiency and acoustic noise optimization are lost

Engineering Contradiction:
Improvedrive powerVSAvoidoperational efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies dynamics by enabling the motor to dynamically select between two operating ranges based on the submarine's travel condition and speed requirements. The control device determines whether to operate in the first operating range (series connection of winding phases) for efficiency optimization or the second operating range (parallel connection) for higher power, adjusting this decision dynamically based on real-time conditions. This resolves the contradiction by allowing the system to adapt its operating mode rather than being fixed in one state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by pre-defining the two operating ranges with their respective characteristics before operation begins. The control device has predetermined knowledge of when to switch between ranges based on propeller curves and travel conditions, allowing for optimized operation without real-time calculation complexity. This resolves the contradiction by preparing the system with pre-optimized operating modes that can be selected based on anticipated operational requirements.

Inventive Principle:
Principle #10Preliminary action

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 approach extends operation in the efficiency and noise-optimized first operating range during underwater travel by accounting for distinct propeller curves, ensuring the submarine maintains optimal performance without requiring significant engine modifications.

Implementation Method 1

an electrical machine designed as a synchronous machine with a rotor excited by a permanent magnet and with a stator in which a stator winding is arranged

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rotor excited by a permanent magnet

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 3

The drive motor (2) has a propeller (101) which is driven by the drive motor (2) to generate thrust for the submarine (100)

Methodology Applied
Scientific EffectHydrodynamic thrust: Drag

Data Source

PatentEP2683605B1Method for operating a submarine and submarine
Publication Date: 2016.02.10 SIEMENS AG
  • EP2683605B1 patent drawingFigure 1
  • EP2683605B1 patent drawingFigure 2~3
  • EP2683605B1 patent drawingFigure 4~5

AI summary

The invention relates to the operation of a submarine (100) which has a pulse inverter supplied drive motor (2) having a coil (5), which is divided into a plurality of coil strands (6, 6'), wherein the motor (2) has a first operating range, wherein a number of the coil strands (6, 6'), preferably two of the coil strands (6, 6'), are connected in series, and a second operating range, wherein the coil strands (6, 6') are connected in parallel, and wherein an operating point (ns,max; nt,max) is defined, wherein a changeover is made from the first operating range to the second operating range, or the reverse, upon reaching said operating point, wherein the operation in the first operating range can be extended in that a different operating point for the changeover is selected during surface travel of the submarine (100) than during submerged travel of the submarine (100).