Single-Phase Inverter Soft Switching via Resonance Circuit

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Solution Overview

Problem

Conventional resonance type inverters require a resonant capacitor connected in parallel with the switching element and necessitate multiple auxiliary switches and capacitors for soft switching, leading to a complex configuration and increased switching losses.

Innovation Solution

A single phase inverter configuration utilizing a resonant capacitor and inductor on the power supply and output sides, respectively, with an auxiliary switching circuit that separates from the power supply, allowing for zero voltage and current switching without the need for multiple auxiliary switches and capacitors, forming a simple resonance circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a resonant capacitor is connected in parallel with the switching element and multiple auxiliary switches and capacitors are used for soft switching, then soft switching is achieved, but the circuit configuration becomes complex and switching losses increase

Engineering Contradiction:
Improveswitching lossVSAvoidcircuit configuration
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The resonant capacitor is extracted from the parallel connection with the switching element and placed on the power supply side of the bridge circuit. This extraction eliminates the need for multiple auxiliary switches and capacitors, simplifying the circuit configuration while maintaining soft switching capability through the resonance circuit formed by the resonant capacitor and resonant inductor

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The resonant capacitor on the power supply side serves multiple functions: it enables soft switching for the switching elements, forms a resonance circuit with the resonant inductor, and eliminates the need for separate auxiliary switching circuits. This multi-functionality reduces overall circuit complexity while achieving the soft switching objective

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

2Reliability

If multiple auxiliary switches and capacitors are used for soft switching, then soft switching is achieved, but the number of circuit elements increases

Engineering Contradiction:
Improvesoft switchingVSAvoidnumber of circuit elements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The resonant capacitor is merged into the main power supply circuit rather than being separate auxiliary components. The resonance circuit is formed by combining the resonant capacitor on the power supply side with the resonant inductor on the output side, eliminating the need for multiple separate auxiliary switches and capacitors, thus reducing the total number of circuit elements while maintaining soft switching reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resonant capacitor serves multiple functions within the inverter circuit, enabling soft switching without requiring dedicated auxiliary switches and capacitors. This multi-functional design reduces the quantity of circuit elements needed while ensuring reliable soft switching operation

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 configuration enables soft switching with reduced switching losses and a simpler circuit design, achieving zero voltage and current switching efficiently.

Implementation Method 1

a resonance circuit is configured by a resonant capacitor provided on the power supply side of a bridge circuit, and a resonant inductor provided on the output side of the bridge circuit constituting a single phase inverter, and a resonance current passing through the resonance circuit allows zero voltage switching (ZVS) and zero current switching (ZCS) to be implemented

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2966771B1Single-phase inverter
Publication Date: 2018.11.14 KYOSAN ELECTRIC MFG CO LTD
  • EP2966771B1 patent drawingFigure 1A~1D
  • EP2966771B1 patent drawingFigure 2
  • EP2966771B1 patent drawingFigure 3A~3B

AI summary

In an inverter circuit, more particularly in a single-phase inverter, soft switching is performed with a simple configuration to prevent switching loss of a switching element. A resonance circuit is configured by a resonant capacitor provided on the power supply side of a bridge circuit constituting a single phase inverter, a resonant inductor provided on the output side of the bridge circuit, and the bridge circuit. A resonance current passing through the resonance circuit allows zero voltage switching (ZVS) and zero current switching (ZCS) to be implemented at the rising time of main switching elements constituting the bridge circuit, and the zero voltage switching is implemented by means of zero voltage of the resonant capacitor at the falling time of the main switching elements constituting the bridge circuit.