Apparatus for detecting current direction in bridge circuits and method thereof
US6781385B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2002 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Nov 8, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to an apparatus and a method for detecting a current direction in a PWM converter or an inverter having one or more upper and lower arms, each of which consists of a switching device with an anti-parallel diode. The voltage across the switching device presents a different value and a polarity that depend on the direction of the current flowing through the switching device, wherein the current direction is acquired by sampling this voltage in the period of the trigger signal being on. In a case of small current, this sampled voltage value is relatively large to the flowing current magnitude and is easy to be distinguished. Furthermore, this invention presents a method for obtaining the phase angle between the load current and the output voltage, and judging whether the output current is zero or includes DC component. As a result, this method presents high precision.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.