Overvoltage protection of a frequency converter
US7430101B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 2006 |
| Grant date | Sep 30, 2008 |
| Priority date | — |
| Expiry date | Apr 14, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/32
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overvoltage protection system for the intermediate circuit of frequency converter, said frequency converter being a voltage-controlled PWM-frequency converter comprising an uncontrolled mains bridge (10) to be connected to an alternating-current source (UL1, UL2, UL3), a direct-voltage intermediate circuit and a controlled load bridge (12) for producing a multi-phase alternating voltage (UU, UV, UW) of variable frequency, wherein the direct-voltage circuit of the frequency converter contains a low-capacitance direct-voltage capacitor, the mains bridge (10) being connected to the load bridge (12) directly without a high-capacitance direct-voltage capacitor serving as an intermediate energy storage, and which overvoltage protection system contains a varistor (R1). The overvoltage protection system consists of a series connection of the varistor (R1) and a semiconductor switch (V1), said series connection being connected in parallel with the direct-voltage capacitor, which semiconductor switch has a voltage rating lower than the normal operating level of the direct-voltage intermediate circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.