| A computer
controlled CVL power supply
Specifications of Power supply
for 30W CVL
o Pulsed Voltage 20kV
o Peak Pulsed Current 800A
o Rise Time 80ns
o Average Power 5.5kW
o Pulsed generator scheme
Thyratron based
Capacitor to capacitor
Charge transfer circuit
o Size 19", 32U Rack
|
The Earlier supplied
developed were thyratron based and their specification
are given below figure.
IGBT based pulse power
supply for Copper Vapor Laser
Insulated gate bipolar transistor (IGBT) based pulse
power supply for 30W average power copper vapor laser is
developed in Laser Systems Engineering Section (LSED).
This power supply will replace conventional thyratron
based power supply. In conventional thyratron based power
supply (specifications in Table1), hydrogen thyratron is
used as the high voltage, high power and fast switch. The
hydrogen thyratron has typical life of 1200 hours after
which the thyratron has to be replaced. The thyratron is
imported and costly component and is subjected to export
restrictions from the country of origin.
The IGBT based power supply uses industry standard IGBTs
(EUPEC BSM400GA120 DN2) rated for 1200V, 400A and
magnetic pulse compressors. A step up pulse transformer
is used to change the voltage level from 1kV to 22kV. The
IGBTs have much longer MTBF as compared to the thyratron
and thus operating expenses of the copper vapor system
due to switch will reduce substantially (see table 2).
The IGBT based power supplies have given the same laser
output power from the corresponding laser head as that of
the conventional power supplies.
Table1. Specifications of the pulse
power supply for 30W average output power CVL
| Peak
voltage |
22kV |
|
Peak
current |
800A |
|
Rise
time |
<100ns |
|
Pulse
repetition frequency |
5-7kHz |
|
Average
power |
6kW |
|
Nature
of load |
Gas
discharge load at low pressure |
Table 2.
Comparison of conventional & IGBT based power supply
units based on switch cost.
| Sr. |
Pulse
Power supply circuit |
Main
Switch cost Rs. |
Estimated
Switch life time |
Estimated
running cost due to switch |
|
1 |
Thyratron
based |
2,50,000 |
1200hrs |
Rs
208 per hour |
|
2 |
IGBT
based |
30,000 |
250000hrs |
Rs.
0.12 per hour |
|
| Programmable Nanosecond delay
generator units: Features:
1. Standard EURO size PCB
2. Front panel and/or PC controlled
3. Optical fiber interface for data communication to PC
4. Can be easily adopted for other delay ranges.
|
Programmable nanosecond delay generators are required
in many experiments along with Laser system. Master
Oscillator Power amplifier system of gas lasers also
requires such delay generators for precisely tuning the
triggering of individual laser unit. In Laser Systems
Engineering Division (LSED) Various models of low cost
multi channel programmable delay generators having range
of 255ns and resolution of 8 bits are developed. In order
to achieve reliable operation in the high EMI environment
of pulse gas discharge lasers, the synchronizing time
mark pulse is transmitted on the glass optical fiber.
|
