Hybrid Drive System Power Balancing via Dual Stator Generator

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Solution Overview

Problem

Traction vehicles face inefficiencies in drive systems that rely on either external electrical power or internal fuel-powered motors, often requiring complex power management and additional components, which can increase costs and mechanical complexity.

Innovation Solution

A drive system with a generator driven by a fuel-powered motor, featuring two galvanically separated stator winding systems and converter branches, allowing for automatic power balancing between external DC network power and internal motor power, reducing the need for additional starting devices and simplifying power transfer control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traction vehicle uses an internal fuel-powered generator to provide electrical power, then the vehicle can operate independently of external electrical networks, but the mechanical complexity and device size increase due to additional components

Engineering Contradiction:
Improveoperational independenceVSAvoidmechanical complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the fuel-powered generator and drive motors into a single integrated drive system where the generator serves dual purposes: generating electrical power for the motors and providing mechanical torque directly to the drive train. This merging eliminates the need for separate starting devices and reduces overall system complexity while maintaining operational independence.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The generator is designed to perform multiple functions: it generates electrical current for the drive motors, provides direct mechanical torque to the drive train, and can operate in different modes (generating mode, motor mode, idle mode) depending on vehicle needs. This multi-functionality reduces the number of separate components required, thereby reducing device complexity while maintaining versatility.

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

2Loss of energy

If a traction vehicle uses a three-phase generator with rectification and conversion, then efficient power conversion is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvepower conversion efficiencyVSAvoidconversion system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex rectification and conversion stages from the power train by using a single-phase generator that directly produces the required electrical output. This removal of unnecessary intermediate conversion steps simplifies the system while maintaining efficient power delivery to the drive motors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex electrical conversion systems (rectifiers, inverters, converters) with a directly coupled mechanical-electrical system where the generator's electrical output is directly suitable for the motors. This substitution eliminates multiple electrical conversion stages and their associated control systems, reducing device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a traction vehicle uses separate starting devices for the fuel-powered motor, then reliable starting is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvestarting reliabilityVSAvoidstarting system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The generator is designed to be self-starting, utilizing its own electrical output to initiate rotation and bring the fuel-powered motor to operating speed. This self-service starting mechanism eliminates the need for external starting devices while ensuring reliable starting through the system's own integrated components.

Inventive Principle:
Principle #25Self-service

4Device complexity

If a traction vehicle uses a compact drive system, then device size is reduced, but power balancing between multiple power sources becomes more difficult

Engineering Contradiction:
Improvesystem compactnessVSAvoidpower balancing control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent merges the electrical and mechanical power paths into a single integrated system where the generator and drive motors share a common mechanical coupling. This merging naturally balances power flow between the two power sources through their direct mechanical connection, simplifying control while maintaining system compactness.

Inventive Principle:
Principle #5Merging (Combining)

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

The system provides a powerful, efficient, and compact drive solution by automatically balancing power from both sources, reducing mechanical components and costs, while ensuring reliable operation with either external electrical power or internal fuel-powered support.

Implementation Method 1

a generator driven by a fuel-powered motor and having two galvanically separated stator winding systems

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

each converter branch comprising a generator side inverter supplied by one of the stator winding systems, a DC link and a drive motor side inverter connected to the DC link

Methodology Applied
Scientific EffectElectrical conversion:

Data Source

PatentEP3558744B1Hybrid drive system for a traction vehicle
Publication Date: 2021.10.13 ABB (SCHWEIZ) AG
  • EP3558744B1 patent drawingFigure 1
  • EP3558744B1 patent drawingFigure 2

AI summary

A drive system (10) of a traction vehicle comprises a generator (16) driven by a fuel powered motor (12), a generator side inverter (24) supplied by the generator (16), a DC link (28) supplied by the generator side inverter (24) and a drive motor side inverter (30) connected to the DC link (28) supplying at least one drive motor (32), wherein the DC link (28) is directly connectable with an electrical DC network (34) for supplying the traction vehicle. A method for operating the drive system (10) comprises: determining a reference power to be provided to the at least one drive motor (32); determining an actual DC network power provided by the DC network (34); and, in the case, the actual DC network power is smaller than the reference power: controlling the fuel powered motor (12), such that a difference power is provided by the generator (16).