Compensation Network for Zero-Voltage Switching in Boost Converters

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Solution Overview

Problem

Boost converter systems experience inefficiencies and high switching losses when the input voltage is greater than half the output voltage, leading to reduced power density and increased switching frequencies.

Innovation Solution

The implementation of a compensation network that includes a comparator, logic gate, and a ZVS switch, which enables zero-voltage switching by determining the relationship between input and output voltages and controlling the switching device to minimize voltage drops across the switching device, thereby reducing switching losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional switching operation is used in boost converter systems when input voltage is greater than half the output voltage, then the converter can operate, but switching losses increase and power density decreases

Engineering Contradiction:

Improveswitching lossesVSAvoidpower density

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The compensation network is activated before the main switching device turns on to pre-discharge the switching device voltage to zero. This preliminary action ensures that when the switching device subsequently turns on, there is no voltage across it, eliminating switching losses while maintaining high power density operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A compensation network including a ZVS switch, comparator, and logic gate is introduced as an intermediary between the input voltage source and the main switching device. This intermediary circuitry manages the voltage transition and enables zero-voltage switching conditions, resolving the contradiction between reducing switching losses and maintaining power density

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If switching frequency is increased to improve power density, then power density increases, but switching losses increase

Engineering Contradiction:

Improvepower densityVSAvoidswitching losses

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The compensation network converts the harmful effect of high switching frequency (which causes switching losses) into a benefit by enabling zero-voltage switching. The circuit uses the switching frequency to drive the compensation network, which in turn eliminates the voltage stress that would cause losses, thus converting the harmful high-frequency switching into a beneficial zero-loss operation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If zero-voltage switching is implemented using compensation network, then switching losses are reduced and power density increases, but device complexity increases

Engineering Contradiction:

Improveswitching lossesVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The compensation network is designed to perform multiple functions: it detects voltage conditions via the comparator, controls the ZVS switch timing via the logic gate, and enables zero-voltage switching for the main device. This multi-functionality reduces the need for separate control circuits and sensors, thereby limiting the increase in device complexity while achieving significant reductions in switching losses and improvements in power density

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 allows for full zero-voltage switching under all operating conditions, increasing switching frequency and enhancing power density, with reduced component sizes and costs in power converter systems.

Implementation Method 1

A compensation network includes a comparator, logic gate, and a ZVS switch, which enables zero-voltage switching by determining the relationship between input and output voltages

Methodology Applied

Scientific EffectVoltage comparison:

Implementation Method 2

enables zero-voltage switching by determining the relationship between input and output voltages and controlling the switching device to minimize voltage drops across the switching device, thereby reducing switching losses

Methodology Applied

Scientific EffectZero-voltage switching:

Data Source

PatentUS11018587B2Methods and apparatus to reduce switching losses in power converters

Publication Date: 2021.05.25 TEXAS INSTRUMENTS INC

AI summary

Methods, apparatus, systems and articles of manufacture are disclosed to reduce switching losses occurring in power converters. An example a converter including an input voltage node and an output voltage node, a controller coupled to the converter, and a compensation network coupled to the converter and to the controller, the compensation network adapted to conduct a current to the converter in response monitoring a first voltage at the input voltage node being a threshold difference than a second voltage at the output voltage node.