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Title: Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova

Abstract

New switching power supplies were designed for the 10 mm laser amplifiers in the Nova Master Oscillator Room. The flashlamp supply must be repratable. Therefore, we designed a constant current, linearly charging power supply. Since it is a capacitor, the load varies throughout the charge cycle. At first the load is great, and di/dt of load current is at a maximum. As the capacitor charges the initial conditions for each cycle change, the power supply in effect sees a smaller capacitance, and di/dt decreases. We need a way of gradually increasing the on-time of the current pulses so that the transistors in the power bridge are turned off when they reach their maximum peak current. The normal current sense response of the control chip is not fast enough to be useful for our application. The deadtime, or the time that all the bridge transistors are turned off, is fixed so that as the pulse width varies so does the period. We end up with a constant peak current, switching power supply whose frequency varies from 50 khz to 20 khz. Finally, an overcurrent latch protects the transistors from bridge or transformer faults. The circuit is described and results are shown.

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
OSTI Identifier:
5639478
Report Number(s):
UCRL-88670; CONF-830621-42
ON: DE83018184
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: IEEE power electronics specialists conference, Albuquerque, NM, USA, 6 Jun 1983
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CAPACITORS; SWITCHING CIRCUITS; NOVA FACILITY; POWER SUPPLIES; CONTROL SYSTEMS; OVERCURRENT; ELECTRICAL EQUIPMENT; ELECTRONIC CIRCUITS; ELECTRONIC EQUIPMENT; EQUIPMENT; 700203* - Fusion Power Plant Technology- Power Supplies, Energy Storage; 700208 - Fusion Power Plant Technology- Inertial Confinement Technology

Citation Formats

Mihalka, A M. Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova. United States: N. p., 1983. Web.
Mihalka, A M. Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova. United States.
Mihalka, A M. Mon . "Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova". United States. https://www.osti.gov/servlets/purl/5639478.
@article{osti_5639478,
title = {Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova},
author = {Mihalka, A M},
abstractNote = {New switching power supplies were designed for the 10 mm laser amplifiers in the Nova Master Oscillator Room. The flashlamp supply must be repratable. Therefore, we designed a constant current, linearly charging power supply. Since it is a capacitor, the load varies throughout the charge cycle. At first the load is great, and di/dt of load current is at a maximum. As the capacitor charges the initial conditions for each cycle change, the power supply in effect sees a smaller capacitance, and di/dt decreases. We need a way of gradually increasing the on-time of the current pulses so that the transistors in the power bridge are turned off when they reach their maximum peak current. The normal current sense response of the control chip is not fast enough to be useful for our application. The deadtime, or the time that all the bridge transistors are turned off, is fixed so that as the pulse width varies so does the period. We end up with a constant peak current, switching power supply whose frequency varies from 50 khz to 20 khz. Finally, an overcurrent latch protects the transistors from bridge or transformer faults. The circuit is described and results are shown.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1983},
month = {6}
}

Conference:
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