Multi-level Inverter Switch Banks for Heat Reduction
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Solution Overview
Problem
Conventional inverters for converting direct current (DC) to alternating current (AC) are large and generate significant heat, making them inefficient for powering AC devices with DC power sources like photovoltaic cells and batteries.
Innovation Solution
A DC to AC inverter design utilizing three capacitors and two switch banks, with a control circuit that configures the switches to create a Pulse Width Modulated waveform, reducing the voltage rating and size of individual switches, and employing a low-pass filter to generate an AC signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional inverter designs are used, then DC to AC conversion is achieved, but the inverter becomes large and generates significant heat
Solution Approach 1:
The inverter is divided into multiple switch banks (first switch bank, second switch bank, third switch bank) that operate in coordinated segments. Each switch bank handles a portion of the power conversion, distributing the heat generation and allowing for more manageable component sizing. The multi-level voltage structure segments the voltage conversion into stages, reducing stress on individual components.
Solution Approach 2:
The patent employs a multi-level voltage structure where DC input voltage is converted through intermediate voltage levels before reaching AC output. This parameter transformation approach allows for lower voltage ratings on individual switches compared to conventional single-stage inverters, enabling the use of smaller, more efficient switching devices that generate less heat.
2Productivity
If conventional inverter designs are used, then DC to AC conversion is achieved, but the inverter becomes large
Solution Approach 1:
The inverter architecture is segmented into multiple switch banks operating in parallel or series combinations, allowing for more efficient power conversion with reduced component sizes. The segmentation enables better utilization of switching devices and reduces the overall volume required for the same power conversion capability.
Solution Approach 2:
The patent introduces a multi-level voltage dimension, converting DC voltage through multiple intermediate levels rather than a single stage. This dimensional approach to voltage conversion allows for more compact switch designs and reduces the overall inverter volume while maintaining or improving conversion efficiency.
3Power
If higher voltage ratings are used for switches, then power handling capability is improved, but switch size and heat generation increase
Solution Approach 1:
The power handling is segmented across multiple switch banks, each operating at lower voltage ratings than a single conventional switch would require. This segmentation allows the system to handle high total power while using smaller, lighter switching devices that generate less heat.
Solution Approach 2:
The patent transforms the voltage parameter through multiple conversion stages, allowing individual switches to operate at lower voltage ratings while the system as a whole handles high power. This parameter transformation enables the use of smaller switches with reduced weight and heat generation.
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 results in a more compact and efficient inverter that effectively converts DC to AC with reduced heat generation, improving power conversion efficiency and size, suitable for use in various DC power applications.
Implementation Method 1
A DC to AC inverter design utilizing three capacitors and two switch banks
Implementation Method 2
employing a low-pass filter to generate an AC signal
Data Source
AI summary
Various examples are directed to systems and methods for a multi-level inverter to convert direct current (DC) to alternating current (AC). The inverter may comprise first, second and third capacitors electrically coupled in series between a positive DC rail and a negative DC rail. A first pole switch bank of the inverter may comprise a plurality of first pole switches. A first pole may be electrically coupled to the first pole switch bank. A control circuit may comprise at least one processor that is programmed to alternately switch the first pole switch bank to a first state of the first pole switch bank in which the first pole is electrically coupled to the positive DC rail, a second state of the first pole switch bank in which the first pole is electrically coupled between the first capacitor and the second capacitor, a third state of the first pole switch bank in which the first pole is electrically coupled between the second capacitor and the third capacitor, a fourth state of the first pole switch bank in which the first pole is electrically coupled to the negative DC rail.