Method and apparatus for the safe limitation of motor torque in a three-phase drive
US11387767B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 2020 |
| Grant date | Jul 12, 2022 |
| Priority date | — |
| Expiry date | Jul 10, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A torque-limiting safety circuit servo drive for AC permanent magnet motors including a three-phase inverter bridge, a first current sensor in series with a first motor phase, a second current sensor in series with a second motor phase, a third current sensor in series with the DC bus, and a drive control circuit that controls the six pulse-width modulated gate drive signals for the three-phase inverter bridge. The drive circuit has first and second safety channel STO inputs whereby either channel can shut down the three-phase inverter bridge, emits a signal set to represent the switching state of the three-phase inverter bridge, and modifies the switching pattern of the PWM to ensure the dwell times of PWM is sufficiently long to allow a valid measurement of phase current using the bus current sensor. First and second safety processors controls the first and second safety channel STO inputs, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.