Speed control apparatus for a brushless direct current motor
US4855652A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | Jan 25, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/907
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
AC power supply is converted to DC by a rectifier circuit. The DC is stepped up by a step-up chopper circuit. The output of the step-up chopper circuit is smoothed by a smoothing circuit. The output of the smoothing circuit is input to an inverter via a current detecting circuit and a voltage detecting circuit. A synchronous motor is connected to the inverter. When the speed of the synchronous motor is judged to be in a high speed region based on the output signal of the voltage detecting circuit, the first speed control apparatus operates the interrupting control of the switching element of the step-up chopper circuit in such a manner that a deviation speed between an instruction speed signal to the motor and the detected speed of the motor reaches to zero. When the duty ratio of the inverter reaches to 100%, that is, when the speed of the motor reaches to a low speed region, the first control speed apparatus controls the switching element of the step-up chopper circuit based on the output signal of the current detecting circuit, and the second control speed apparatus carries out the pulse width modulation control of the inverter in such a manner that a deviation speed signal betw…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.