Abstract
As power-switches improve, the primary function of switching-aid circuits changes from modifying the shape or rate-of-traverse of V-I loci within device
safe-operating-areas (SOA's), to clamping transient current and voltage, at turn-on and turn-off, below peak current and voltage ratings. Also, as device
ruggedness and device parameters are improved, or made less variable between devices and with operating conditions, active-snubbing or active-clamping becomes feasible, whereby the magnitude of peak-current at turn-on and peak-voltage at turn-off are limited by gate or drive-circuit control, or inherently by the devices themselves. Examples have been reported, however, none of these adequately compares active and passive snubbing, or exposes salient disadvantages in active-snubbing. A more objective appraisal of active snubbing
is attempted here, which uses as its basis for comparison; turn-on and turn-off commutation energy-loss, on-state energy-loss, overload capacity,
and turn-on and turn-off delay. Irrespective of whether active or passive snubbers or clamps are used, switch turn-off voltage-waveforms are often characterised by fast voltage-overshoot above the dc-supply voltage, or above the threshold-level of voltage-clamps, when used. High-frequency ringing
inevitably follows turn-off, or the beginning or end of voltage-clamping. The cause and solution are examined.
safe-operating-areas (SOA's), to clamping transient current and voltage, at turn-on and turn-off, below peak current and voltage ratings. Also, as device
ruggedness and device parameters are improved, or made less variable between devices and with operating conditions, active-snubbing or active-clamping becomes feasible, whereby the magnitude of peak-current at turn-on and peak-voltage at turn-off are limited by gate or drive-circuit control, or inherently by the devices themselves. Examples have been reported, however, none of these adequately compares active and passive snubbing, or exposes salient disadvantages in active-snubbing. A more objective appraisal of active snubbing
is attempted here, which uses as its basis for comparison; turn-on and turn-off commutation energy-loss, on-state energy-loss, overload capacity,
and turn-on and turn-off delay. Irrespective of whether active or passive snubbers or clamps are used, switch turn-off voltage-waveforms are often characterised by fast voltage-overshoot above the dc-supply voltage, or above the threshold-level of voltage-clamps, when used. High-frequency ringing
inevitably follows turn-off, or the beginning or end of voltage-clamping. The cause and solution are examined.
| Original language | English |
|---|---|
| Title of host publication | 14 Annual Conference of Industrial Electronics Society. IECON '88. |
| Place of Publication | Singapore |
| Publisher | IEEE |
| Pages | 617-622 |
| Number of pages | 6 |
| Volume | 3 |
| DOIs | |
| Publication status | Published - 1988 |
| Event | 14th Annual Conference of Industrial Electronics Society, 1988. IECON 1988 - Singapore, Singapore Duration: 24 Oct 1988 → 27 Oct 1988 |
Conference
| Conference | 14th Annual Conference of Industrial Electronics Society, 1988. IECON 1988 |
|---|---|
| Country/Territory | Singapore |
| City | Singapore |
| Period | 24/10/88 → 27/10/88 |