Forward Converter Battery Charger Phase Shift Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional battery chargers are inefficient due to oversized components resulting from designing for the highest rated battery, leading to inefficiencies when charging batteries of lower ratings.

Innovation Solution

The system dynamically adjusts output voltage by manipulating duty cycles and phase shifts of forward converter circuits, using a controller to generate pulse width modulation signals based on battery charge state and rating, and incorporating leading or lagging edge compensation for transformer core reset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power supply circuit is designed to handle the highest rated battery, then the charger can accommodate all battery types, but the components become oversized and efficiency decreases when charging lower voltage batteries

Engineering Contradiction:

Improvebattery voltage rangeVSAvoidcharging efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The power supply circuit is divided into two separate forward converter circuits operating in parallel, each optimized for different voltage ranges. This segmentation allows each circuit to operate at optimal efficiency for its designated voltage range while collectively covering the full battery voltage spectrum from 6V to 48V

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the operation of the two forward converter circuits based on the detected battery voltage. The controller monitors battery voltage and automatically configures which circuit operates and how they work together, transitioning between different operational modes to maintain optimal efficiency across varying load conditions

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a single forward converter circuit is used, then the circuit design is simpler, but the ability to efficiently handle varying voltage requirements is limited

Engineering Contradiction:

Improvecircuit configurationVSAvoidvoltage output range

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

Two forward converter circuits are merged and operated in parallel with their outputs combined through a common inductor. This merging allows the system to achieve extended voltage output capability while maintaining relatively simple individual circuit designs that can be mass-produced and standardized

Inventive Principle:

Principle #5Merging (Combining)

3Power

If the duty cycle is increased to raise output voltage, then the voltage output increases, but the transformer core requires more time to reset which limits maximum duty cycle

Engineering Contradiction:

Improveoutput voltageVSAvoidtransformer core reset time

Core Design Contradiction:

PowerVSDuration of action of moving object

Solution Approach 1:

The system uses periodic switching of the two forward converter circuits with phase shifting between them. By alternating their operation and adjusting the phase difference, the system can maintain continuous power delivery while allowing each transformer sufficient reset time between its active periods

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

While one forward converter circuit is resetting its transformer core, the other circuit continues to deliver power to the load. This overlapping operation ensures continuous useful action without interruption, maintaining power delivery while respecting the reset time requirements of each transformer

Inventive Principle:

Principle #20Continuity of useful 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 allows for efficient handling of varying load requirements, reducing inefficiencies and optimizing component usage across different battery types and voltages, enhancing charging efficiency and reducing recharge time.

Implementation Method 1

a first converter circuit and a second converter circuit, each having an output connected to a common inductor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a controller configured to generate pulse width modulation signals that control a duty cycle of the converter circuits

Methodology Applied

Scientific EffectPulse width modulation: Phase Modulation

Data Source

PatentUS8179100B2Battery charger using the phase shift by a pair of forward converting circuits

Publication Date: 2012.05.15 ILLINOIS TOOL WORKS INC

AI summary

A technique for dynamically adjusting an output voltage of forward converter circuits for a battery charging operation is provided. The technique allows for varying voltage at the charging battery by manipulating the duty cycles of two forward converter circuits. Method and systems allow for increasing synchronized duty cycles in a pair of forward converter circuits in response to a changing battery charge state that requires a higher voltage output then changing a phase shift between the duty cycles in response to further increases in output voltage demand. The methods and systems also allow for setting a phase shift between duty cycles in a pair of forward converter circuits based on battery rating and then altering pulse width in response to changing battery charge state.