Multi-Level Inverter APW Architecture Harmonic Reduction

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Solution Overview

Problem

Existing AC power generation technologies face challenges in minimizing harmonic distortion and maintaining zero voltage offset, particularly in solid state inverter solutions used for converting DC to AC power, which affect efficiency and cost-effectiveness.

Innovation Solution

The implementation of a DC to AC converter-inverter with an amplitude pulse width (APW) architecture that employs a stepped DC voltage energy source and semiconductor switches, including SiC MOS-FETs, to generate a multi-level stepped voltage waveform with modulated width, reducing harmonic distortion and eliminating voltage offset through a bridge circuit and harmonic filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If solid state inverter solutions are used to convert DC to AC power, then efficiency and cost are improved, but harmonic distortion increases and voltage offset is introduced

Engineering Contradiction:

Improveconversion efficiencyVSAvoidharmonic distortion

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The inverter divides the DC voltage into multiple discrete levels using series-connected battery strings (e.g., four 48V batteries creating five voltage levels: 0V, 48V, 96V, 144V, 192V). This segmentation of the voltage source creates a multi-level stepped waveform that better approximates a sine wave, reducing harmonic distortion while maintaining solid state efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the width of each voltage step (amplitude pulse width modulation) to track the sine wave envelope. By varying the duration of each voltage level in proportion to the instantaneous sine wave amplitude, the inverter eliminates voltage offset and reduces harmonics while maintaining high conversion efficiency.

Inventive Principle:

Principle #15Dynamics

2Productivity

If traditional PWM techniques are used, then conversion efficiency is improved, but voltage offset and harmonic distortion are not eliminated

Engineering Contradiction:

Improveconversion efficiencyVSAvoidsignal purity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system changes the fundamental parameter of voltage amplitude by using multiple discrete voltage levels instead of a single DC level. This parameter change from single-level to multi-level voltage output fundamentally improves signal purity by reducing harmonic distortion and eliminating voltage offset while maintaining high conversion efficiency.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If rotational electro mechanical generators are used, then signal purity is improved, but cost and complexity increase

Engineering Contradiction:

Improvesignal purityVSAvoidsystem complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical rotational generators with a solid state electronic system using battery strings and semiconductor switches. This substitution eliminates moving parts and mechanical complexity while achieving comparable or superior signal purity through multi-level voltage synthesis and amplitude pulse width modulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the efficiency and reduces costs by generating high-quality AC power with reduced harmonic distortion and zero voltage offset, supporting integration of renewable energy and real-time load balancing in a Personal Power Plant system.

Implementation Method 1

A plurality of Schottky diodes can be disposed between a corresponding semiconductor switch of the plurality of semiconductor switches and the bridge circuit to prevent reverse current flow and reduced transistor switching losses

Methodology Applied

Scientific EffectDiode rectification: Diode

Implementation Method 2

a bridge circuit, which is electrically connected to the plurality of semiconductor switches and configured to switch a polarity of a voltage applied to a load coupled thereto

Methodology Applied

Scientific EffectElectrical switching:

Implementation Method 3

the inverter may further comprise a harmonic filter, to reduce voltage and current spikes and harmonics in the multi-level stepped waveform

Methodology Applied

Scientific EffectHarmonic filtering: Filter (electronic)

Data Source

PatentUS11677333B2Multi switch inverter, personal power plant system using thereof and method to generate AC power sine wave

Publication Date: 2023.06.13 SUPERPOWER ENERGY INC

AI summary

An inverter with an amplitude pulse width (APW) architecture that generates a single phase AC (Alternating Current) power waveform is disclosed. The inverter generates a multi-level stepped voltage waveform, each step of the multi-level stepped waveform having a modulated width of a selected voltage. The inverter further comprises a soft fuse protection system. This disclosure also relates to a personal power plant system using said inverter and a method to generate an AC power sine wave with reduced harmonic distortion.