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Overvoltage Crowbar Protection Based on Passive Power Supplied Control Unit Cover

Overvoltage Crowbar Protection Based on Passive Power Supplied Control Unit

Open Access
|Nov 2025

Figures & Tables

Figure 1.

Cascaded H-bridge cells concept.

Figure 2.

H-bridge cell overvoltage protection implementation (Strossa et al., 2024).

Figure 3.

Proposed overvoltage protection power circuit, link capacity discharging current loop of the first stage thyristor T1 activated (a), link capacity discharging current loop of the second stage thyristor T2 activated (b), crowbar excited inductor current after link capacity discharged (c).

Figure 4.

Block diagram of the proposed crowbar overvoltage protection.

Figure 5.

Simplified proposed crowbar overvoltage evaluation control circuit (Strossa et al., 2024).

Figure 6.

Simplified proposed crowbar second-stage triggering control circuit.

Figure 7.

Simplified crowbar thyristor driver (Strossa et al., 2024).

Figure 8.

Simplified optocoupled trigger output.

Figure 9.

Spice simulation of proposed crowbar intervention, H-bridge cell input capacity voltage VCIN (V), 50 V/div, clamping input capacity discharging current IL (A), 18 A/div and thermal integral i2t (A2s), 25 A2s/div, timebase 50 ms/div.

Figure 10.

Experimental set-up (Strossa et al., 2024).

Figure 11.

Experimental waveforms after crowbar intervention of H-bridge (Strossa et al., 2024), input capacity voltage VCIN (V), 100 V/div and crowbar clamping current IL (A), 50 A/div, time base 10 ms/div.

Figure 12.

Experimental waveforms after crowbar intervention of H-bridge (Strossa et al., 2024), input capacity voltage VCIN (V), 100 V/div and crowbar clamping current IL (A), 50 A/div, time base 250 μs/div, detailed current rising is scoped.

Figure 13.

Experimental waveforms after crowbar intervention of H-bridge (Strossa et al., 2024), input capacity voltage VCIN (V), 100 V/div, crowbar clamping current IL (A), 50 A/div and trip voltage on the secondary side of optocoupler VTRIP (V), 10 V/div, time base 50 ms/div, trip signal observed.

Crowbar power devices requirements_

SymbolParameterValue
di/dtThyristor switching current slope150 A/µs
IMAXMaximum thyristor anode current100 A/20 ms
i2tThyristor thermal energy integral88 ASs
LCrowbar Inductivity170 µH
ILMAXMaximum inductor non-saturating current115 A
RCrowbar resistivity2,6 Ω
PRPEAKCrowbar resistor peak power26 kW

H-bridge cell required overvoltage protection parameters (Strossa et al_, 2024)_

SymbolParameterValue
CINH-bridge single cell input capacity4.7 mF
VBRProtection breakdown voltage300 V
IBRMAXMaximum peak of the break clamping current100 A
ΔVSWRIPMaximum ripple of the CIN capacity voltage on the CIN equivalent series inductivity, originated by the pulse width modulation of the H-bridge transistors50 V
fSWH-bridge cell switching frequency100 kHz
DOI: https://doi.org/10.2478/pead-2025-0024 | Journal eISSN: 2543-4292 | Journal ISSN: 2451-0262
Language: English
Page range: 374 - 391
Submitted on: Jul 30, 2025
|
Accepted on: Oct 13, 2025
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Published on: Nov 14, 2025
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year

© 2025 Jan Strossa, Vladislav Damec, Martin Sobek, Pavel Cyprich, Petr Cyprich, Marek Kubatko, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution 4.0 License.