Pulse width modulated inverter system for driving single phase a-c induction motor
US4706180A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 29, 1985 |
| Grant date | Nov 10, 1987 |
| Priority date | — |
| Expiry date | Nov 29, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A substantially perfect single phase sinusoidal shaped voltage waveform may be generated for driving a single phase a-c induction motor by employing a sinusoidally weighted pulse width modulated signal to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies. A low pass filter is effectively connected in series with the single phase motor to filter out all of the signal components except the fundamental of the sine wave modulating frequency. In this way, only a sinusoidal voltage is applied to the motor. By making the switching frequency very high relative to the sine wave modulation component, the filter size and cost are minimized and it is unnecessary to correlate or synchronize the sine wave modulation and switching frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.