Capacitor charge balancing technique for a three-level PWM power converter
US6842354B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 8, 2003 |
| Grant date | Jan 11, 2005 |
| Priority date | — |
| Expiry date | Aug 8, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/487
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power converter includes a DC to AC inverter that is connected to a neutral node formed between first and second capacitors connected across two DC supply lines. The inverter is operated to selectively couple the DC supply lines and the neutral node to an output terminal thereby producing an alternating voltage waveform formed by a sequence of output pulses having positive, zero and negative voltage levels. To compensate for a voltage imbalance across the capacitors, an imbalance compensation coefficient is derived from the difference in voltages across the first and second capacitors and from the direction of current between the neutral node and the inverter. The imbalance compensation coefficient is employed to adjust the width of the output pulses so as to charge and discharge the capacitors to correct the imbalance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.