3-Level Inverter with Segmented Output for Load Control
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Solution Overview
Problem
Conventional 3-level inverters require a large number of semiconductor switch elements, leading to increased cost and reduced load current due to the need for multiple switches to select and control power distribution to multiple loads.
Innovation Solution
A 3-level inverter design that minimizes the number of semiconductor switch elements by using capacitors, diodes, and a control unit to manage the on/off operations of switches, allowing for efficient power distribution to multiple loads with reduced switch requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple bi-directional semiconductor switches are installed to supply AC power to multiple loads selectively, then the ability to control power distribution to multiple loads is improved, but the number of semiconductor switch elements increases and cost increases
Solution Approach 1:
The inverter output is divided into multiple segments (first output terminal and second output terminal) that can independently supply power to different loads. Each segment can be controlled separately through unidirectional switches, allowing selective power distribution without requiring bi-directional switches for each load.
Solution Approach 2:
Instead of using bi-directional switches that can handle both positive and negative current directions, the patent employs unidirectional switches combined with capacitors and diodes to achieve bidirectional power flow capability. The capacitors store energy and enable current to flow in reverse direction through the unidirectional switches, inverting the conventional approach.
2Adaptability or versatility
If multiple bi-directional semiconductor switches are installed to control power distribution, then selective supply to multiple loads is enabled, but load current decreases due to current division through multiple switches
Solution Approach 1:
The output is segmented into independent terminals that can supply current to different loads simultaneously or selectively. Each segment maintains dedicated current paths through unidirectional switches, avoiding current division losses associated with parallel bi-directional switch configurations.
Solution Approach 2:
Capacitors are introduced as intermediary energy storage elements between the inverter bridge and the output terminals. These capacitors enable current redirection and maintain continuous current flow to loads, preventing current loss that would occur through multiple switch paths.
3Ease of operation
If multiple bi-directional semiconductor switches are used for load selection, then power distribution control is improved, but cost increases due to higher number of semiconductor elements
Solution Approach 1:
The patent inverts the conventional approach by using unidirectional switches with capacitor-based energy storage instead of expensive bi-directional switches. This configuration achieves bidirectional power control functionality while using fewer and less expensive unidirectional semiconductor elements.
Solution Approach 2:
The unidirectional switches combined with capacitors and diodes perform multiple functions: current switching, energy storage, voltage regulation, and bidirectional power flow control. This multi-functionality reduces the need for additional dedicated components, lowering overall system cost while maintaining operational flexibility.
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 design reduces the number of semiconductor switch elements needed, lowering costs and improving inverter efficiency by allowing load current to flow through fewer devices while maintaining effective power distribution to multiple loads.
Implementation Method 1
a plurality of capacitors charged with voltages divided from a DC (direct current) input voltage
Implementation Method 2
a plurality of diodes connected in series in a forward direction from the other end of the bottom switch to the other end of the top switch
Data Source
AI summary
The present disclosure relates to a load-segmentation-based 3-level inverter and method for controlling same. Three-level inverter includes: multiple capacitors charged with voltages divided from a DC input voltage; top switch having one end connected with positive terminal of one of multiple capacitors; bottom switch having one end connected with negative terminal of one of multiple capacitors; multiple legs each including a first switch connected to the other end of top switch and a second switch connected to the other end of bottom switch with the first and second switches connected; multiple diodes connected in series forwardly from the other end of bottom switch to the other end of top switch and having interconnect points connected to a contact between the multiple capacitors; and multiple loads having connected terminals at a contact between the first and second switches of each of the legs and a contact between the multiple diodes.