Motor controller and electric tool having the same
US8294399B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 2008 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Oct 16, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P29/032
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor controller comprises a processor selectively outputting an on-signal to either one of an upper arm switching element and a lower arm switching element based upon a detected position by the position sensor, gate drivers inputting a driving voltage to the gates of the switching elements by shifting a level of the on-signal from the processor to the upper arm switching element and a bootstrap capacitor configured to be charged while the upper arm switching element is turned off and to behave as a voltage supply for the gate driver while the upper arm switching element is turned on. The processor is configured to reduce a set duty ratio when the set duty ratio is equal to or larger than a predetermined value (e.g. 80 percents) and a rotational position of the motor does not change for a first predetermined time. This motor controller can prevent the switching element from a burnout even if the motor is locked.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.