Neutral point clamped (NPC) inverter control system
US5790396A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1996 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Dec 12, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/487
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A neutral point clamped (NPC) inverter control system including a DC power source to output DC voltage having a neutral point, an NPC inverter to convert the DC voltage into AC voltage in three phases through a PWM control, a mode selecting unit to decide a first and a second PWM modes by comparing amplitude of voltage reference with a prescribed value that is defined by a minimum pulse width, a first voltage reference conversion means to add a prescribed bias value at which a polarity changes to positive/negative within a fixed period to secure the minimum pulse width to voltage references in respective phases in a first PWM mode, a second voltage reference conversion means to fix the voltage reference in one phase by a value that secures the minimum pulse width when voltage reference in one phase is smaller than a prescribed value that is defined by the minimum pulse width in a second PWM mode and correct voltage references of other two phases so as to make line voltage to a value corresponding to the voltage reference, and a modulation frequency change-over means to lower PWM control modulation frequency in the first PWM mode and to suppress power loss caused by switching in the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.