Alternator Field Winding Switching for Flexible Power Output

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Solution Overview

Problem

Existing alternators in motor vehicles face limitations in adjusting output voltage and power without altering the design, particularly in heavy-duty applications, necessitating inefficient methods like increasing current to the field circuit winding.

Innovation Solution

A field winding circuit for alternators is divided into multiple portions, controlled by electronic switches, allowing dynamic connection to output terminals based on load requirements, with an electronic controller determining and adjusting the connection of these portions to optimize power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the current given to the field circuit winding is increased to generate required output power, then the output power can be increased, but the energy loss and inefficiency increase

Engineering Contradiction:
Improveoutput powerVSAvoidenergy loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The field circuit winding is divided into multiple portions (first winding portion, second winding portion, third winding portion) that can be independently connected or disconnected from the output terminals. This segmentation allows the system to use only the necessary number of winding portions based on load requirements, avoiding energy loss from using all windings when full power is not needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching capability where electronic switches (first switch, second switch, third switch) control the connection of different winding portions to output terminals based on real-time load requirements. This dynamic adjustment allows the alternator to optimize power output and minimize energy loss by activating only the necessary winding portions.

Inventive Principle:
Principle #15Dynamics

2Power

If the number of turns in the field circuit winding is increased to generate required output power, then the output power can be increased, but the device complexity increases

Engineering Contradiction:
Improveoutput powerVSAvoiddevice complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

Instead of using a single large winding with many turns, the patent divides the field circuit winding into multiple portions that can be selectively connected. This segmentation achieves the required power output through parallel combination of fewer-turn windings, reducing the complexity of individual windings while maintaining the necessary power generation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The same field circuit winding portions serve multiple functions: they can be individually connected or combined in different configurations to meet varying power requirements. This multi-functionality eliminates the need for multiple separate windings, thereby reducing device complexity while maintaining power flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a single field circuit winding is used, then the device complexity is low, but the reliability decreases when the coil is damaged

Engineering Contradiction:
Improvedevice complexityVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The field circuit winding is divided into multiple independent portions that can be selectively connected to output terminals. If one winding portion becomes damaged, the electronic controller can detect the fault and reconfigure the circuit to use only the functional winding portions, thereby maintaining system reliability without requiring complete replacement of the field circuit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements reconfigurable circuit topology where the connection parameters of the winding portions can be dynamically changed based on operational conditions and fault detection. This allows the system to adapt to damage by altering which winding portions are active, maintaining reliability while preserving the segmented structure's low complexity advantage.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If the field circuit winding configuration is fixed, then the device complexity is low, but the adaptability to different load requirements decreases

Engineering Contradiction:
Improvedevice complexityVSAvoidadaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic switching capability using electronic switches controlled by an electronic controller. The controller can determine load requirements and automatically configure the appropriate number and arrangement of winding portions connected to output terminals, providing adaptability to different load conditions while maintaining relatively simple device architecture through automated control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The same set of segmented winding portions and switches can be configured in multiple ways to satisfy different power and voltage requirements. This universal configuration capability allows a single alternator design to serve multiple applications and load conditions without requiring complex dedicated circuits for each scenario.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances power output flexibility and redundancy, reducing load dependency and ensuring continued operation even if one coil is damaged.

Implementation Method 1

a stator, one or more magnets affixed to either the rotor or the stator, and a stator winding circuit capable of generating a voltage when a magnetic field created by the magnet(s) or electromagnets (field/rotor winding circuit) is moving relative to the stator/armature winding circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4274086B1Field winding circuit for an alternator, alternator comprising the same, and associated methods
Publication Date: 2025.12.10 VOLVO TRUCK CORP
  • EP4274086B1 patent drawingFigure 1
  • EP4274086B1 patent drawingFigure 2
  • EP4274086B1 patent drawingFigure 3

AI summary

A field winding circuit for an alternator, comprising an electromagnetic coil including a first winding portion and a second winding portion electrically connected in series. The winding circuit comprises a first switch, a second switch and a third switch configured to selectively connect one or both of the first and second winding portions to output terminals of the winding circuit. The winding circuit comprises an electronic controller configured to: determine the output power required by an electrical load connected to the stator output terminals, compare the required output power to a threshold value, connect only one of the first and second winding portions to the output terminals if the required output power is below the threshold value and connect both the first and second winding portions to the output terminals if the required output power is below the threshold value.