Generator Boost Converter Switching Frequency Control

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Solution Overview

Problem

Existing generator systems with variable speed motors face inefficiencies due to high electrical losses at low speeds, particularly in commercial vehicles, where a stable output voltage is required across a wide speed range while minimizing installation space and maintaining energy efficiency.

Innovation Solution

A device comprising a generator, a pulse width modulated step-up converter, and a control system that adjusts switching times of power switches based on generator speed and voltage, using boost factors to optimize switching points and reduce losses, allowing for efficient energy delivery across varying speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a generator operates at variable speed to meet different power demands, then adaptability is improved, but electrical losses increase at low speeds

Engineering Contradiction:
Improvespeed rangeVSAvoidelectrical losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The control frequency of the power switches is dynamically adjusted based on the generator speed. At low speeds, the control frequency is reduced to minimize switching losses, while at higher speeds the frequency increases to maintain efficient power conversion. This parameter adaptation resolves the contradiction by optimizing the switching behavior according to the operating speed regime.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the switching frequency of power switches is increased to improve voltage conversion efficiency, then power conversion efficiency is improved, but switching losses increase

Engineering Contradiction:
Improvevoltage conversion efficiencyVSAvoidswitching losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The control frequency of the power switches is made dynamic rather than fixed. The control device adjusts the switching frequency in real-time based on the instantaneous generator speed and voltage conditions. This dynamic adaptation allows the system to achieve high conversion efficiency when needed while minimizing switching losses during low-speed operation.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If a step-up converter is used to maintain stable output voltage across wide speed ranges, then voltage stability is improved, but device complexity increases

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidconverter complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The step-up converter control is integrated with the generator control system. The control device combines the functions of voltage regulation, frequency adaptation, and power optimization in a single control unit. This merging of functions achieves stable output voltage while avoiding the complexity of separate control systems.

Inventive Principle:
Principle #5Merging (Combining)

4Loss of energy

If pulse width modulation is used to control power switches for efficient energy delivery, then energy efficiency is improved, but harmonic content in output increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidharmonics
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The control system uses periodic pulse width modulation with adaptive duty cycles based on generator speed and voltage conditions. By optimizing the switching pattern and frequency, the system achieves high energy efficiency while the adaptive control minimizes harmonic generation through optimized switching timing and frequency selection.

Inventive Principle:
Principle #19Periodic 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

The solution enables continuous, efficient electrical power generation with reduced switching losses and harmonics, providing a stable output voltage similar to a sine wave, even at low speeds, thus enhancing energy efficiency and reducing torque fluctuations.

Implementation Method 1

a step-up converter whose power switches are controlled

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3264587B1Energy generation system comprising a generator and method for operating such an energy generation system
Publication Date: 2021.02.17 MARTIN SPECIAL TECHNICS GMBH
  • EP3264587B1 patent drawingFigure 1
  • EP3264587B1 patent drawingFigure 2
  • EP3264587B1 patent drawingFigure 3

AI summary

The present invention relates to improving the performance of a generator that works in conjunction with a boost converter and a control unit. For this purpose, the control frequency of the boost converter switches is varied as a function of the generator's rotational speed, with the function operating with switching points and/or variable boost factors.