Input filter for A.C. motor phase current sensing
US6828753B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 2003 |
| Grant date | Dec 7, 2004 |
| Priority date | — |
| Expiry date | Aug 20, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An input filter to block noise components of motor phase current used as an input signal for a PWM motor controller. The input filter includes an integration circuit driven by a triggering signal at a frequency which is twice the frequency of operation of the inverter. In one embodiment, a first integrator is coupled directly to the motor drive current signal, and a second integrator is coupled to the motor drive current signal through a circuit which introduces a delay equal to the period of the triggering signal. The difference between the outputs of the integrators is then sampled at the triggering signal frequency. In a second embodiment, a voltage-to-time converter generates a first ramp representing the integral of the phase current signal during a first triggering interval, and a second ramp representing the integral of a reference signal, is subtracted from the value of the first ramp during a second triggering interval until value of integrator output returns to zero. In a third embodiment, a switched capacitor integration circuit is operated by a high speed clock synchronized to the triggering signal. The integrator output is sampled at the end of each triggering period a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.