Apparatus and method for reducing effective inductance in a dynamic braking circuit
US3991352A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 1975 |
| Grant date | Nov 9, 1976 |
| Priority date | — |
| Expiry date | Jun 19, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P3/24
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are disclosed for reducing effective inductance and providing balanced line-to-line voltages in induction machine dynamic braking circuits which utilize braking resistors to substantially increase the full torque braking range of the machine. The current phase lag caused by the inductive property of conventional braking resistors, is substantially reduced by rectifying the current provided to the braking resistor through a three-phase rectifier bridge. This reduction of the current phase lag permits a reduction in the capacitance required to compensate for the effective inductance in the dynamic braking circuit. Furthermore, because the braking currents flow through a common braking resistor, the line-to-line stator motor voltages are inherently balanced. If the prior art braking impedance control is also employed, the rectifier bridge need carry current only if dynamic braking is required when motor voltage is greater than the maximum voltage of the inverter supplying the machine. Where the braking resistor may be varied in a step-wise manner, the amount of dynamic braking capacitance needed for inductive compensation is reduced below the substantial reducti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.