Variable speed constant frequency start system with selectable input power limiting
US4949021A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1988 |
| Grant date | Aug 14, 1990 |
| Priority date | — |
| Expiry date | Nov 14, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2101/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The problem of providing an engine starting system from any one of a plurality of input power sources is solved with an engine start control apparatus operating a generator as a synchronous motor and employing input power limiting. The motor receives power from a main inverter and an excitation inverter. These inverters are controlled by a control unit which provides for input power limiting and also constant power characteristics in the field weakening range. The control unit includes a pulse width modulation (PWM) generator which is responsive to a voltage command and a commutation command to develop switching signals for controlling the switches in the start inverter. The voltage command is used to vary the duty cycle of the PWM signals. The commutation angle command is used to control the timing of the PWM signals. In addition to commutation angle control, the start control system employs field weakening control to obtain constant power characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.