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Hybrid Multilevel Inverter with DC Bypass

IP.com Disclosure Number: IPCOM000247148D
Publication Date: 2016-Aug-10
Document File: 13 page(s) / 2M

Publishing Venue

The IP.com Prior Art Database

Related People

Liming Liu: AUTHOR [+3]

Abstract

This invention relates to single-phase multilevel inverters with split dc capacitors, and particularly to inverters capable of providing extra path to balance dc voltages. The invention also relates to power conversion system comprising inverters, energy source/storages, and grid/load, such as photovoltaic (PV), power supply, electrical vehicle (EV) charger, etc.

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Page 01 of 13

Hybrid Multilevel Inverter with DC Bypass

Attachment to Invention Disclosure

1Field of invention

Short statement about the application area and the background of the invention

This invention relates to single-phase multilevel inverters with split dc capacitors, and particularly to inverters capable of providing extra path to balance dc voltages. The invention also relates to power conversion system comprising inverters, energy source/storages, and grid/load, such as photovoltaic (PV), power supply, electrical vehicle (EV) charger, etc.

2Problem to be solved

Short statement about the problem the invention tries to overcome

A large number of single-phase grid interactive inverters are used to achieve power conversion from DC to AC in low/medium power application. The growth of wide band gap devices, such as Gallium Nitride (GaN) devices, and more requirements, such as high efficiency, high power density, high power quality, minimized effects of electromagnetic interference (EMI), and effective cost, have driven the inverter development toward more advanced alternatives. The challenge is to design a high efficiency power inverter with fewer switches, small passive components and enhanced reliability.

3Prior art solutions

List the approaches in publications and competitor patents with appropriate citations to references

Multilevel inverters provide a staircase wave and are suitable for the integration of wide band gap devices with low voltage. Therefore, they could be solutions for the above problems. The following solutions are known or proposed for multilevel inverter with split dc capacitors:

Solutions with half-bridge configuration:
o Diode neutral-point-clamped (DNPC) half bridge inverter[1][2] o Half bridge 3-level T-type converter (3LT2C) [3] o Half-bridge inverter within AC side bypass and a bypassable DC-DC converter[4] o Half-bridge three-level flying capacitor inverter[5] Solutions with full-bridge configuration:
o Full bridge zero voltage rectifier [6] o Full bridge inverter with DC bypass [7] o Five level inverter with AC bypass [8]


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o Full bridge diode neutral-point-clamped inverter [9] o High efficiency 3-level single-phase inverter [10] o Cascaded full bridge inverter[11] o Single phase symmetrical multilevel inverter [12][13] Solutions with mixed-level bridge configuration:
o Mixed inverter with DNPC leg and half-bridge leg[14][15] o Mixed inverter with active neutral-point- clamped (ANPC) leg and half-bridge leg[15] o Mixed 3- level inverter with DNPC leg and 3LT2C leg[16] o Mixed inverter with flying capacitor leg and half-bridge leg [17]

Fig. 1 DNPC half-bridge inverter [1][2]

Fig. 3 REFU half-bridge inverter [4] Fig. 4 Half-bridge 3-level flying capacitor inverter [5]

Fig. 2 Half bridge 3LT2C [3]


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Fig. 5 Full bridge zero voltage rectifier [6] Fig. 6 Full bridge inverter with DC bypass[7]

Fig. 7 Five level inverter with AC bypass [8]

Fig. 8 Full bridge DNPC inverter [9]

Fig. 9 High ef...