Method and apparatus for balancing voltages of multi-level inverter DC link
US9595864B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 5, 2014 |
| Grant date | Mar 14, 2017 |
| Priority date | — |
| Expiry date | Jan 24, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/487
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method is provided for balancing voltages of a DC link of a multi-level inverter, where the DC link is divided into two halves by a neutral point connection. The method includes injecting a periodic common-mode voltage injection signal to a common-mode voltage reference and a periodic power injection signal to a power reference of the inverter. The power injection signal has the same frequency as the common-mode voltage injection signal. A phase shift between the common-mode voltage injection signal and the power injection signal is constant. The amplitude of at least one of the common-mode voltage injection signal and the power injection signal is controlled on the basis of a difference between voltages over the two halves of the DC link. An apparatus is also provided for implementing the method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.