Apart for Indus-1 and Indus-2, power supplies have also been developed for other applications.

• Power Supplies for Field Mapping of Quadrupole Magnets
• Power Supplies for Radiotherapy Machine
• Power Supplies for Free Electron Laser
• Power Supplies for Superconducting Magnets
• Scanning Magnet Power Supply
• Power Supplies for Wiggler Magnets
• Modular Magnet Power Supplies for CUTE-FEL Beam Line and Photocathode Gun Based LINAC

Two power supplies have been developed for the field mapping of Indus-2 quadrupole magnets. Two mapping power supplies, rated 170 A, 60 V, 50 ppm stability were needed for testing of quadrupole magnets, one was developed using a transistorized series pass scheme with a SCR bridge pre-regulator and the other using a high frequency resonant converter.

Transistor series pass type mapping supply		Resonant converter type mapping supply

A radiotherapy machine (RTM) is being developed for cancer treatment using electron and gamma rays based on 12 MeV microtron. Apart from microtron main dipole magnet, it consists of four quadrupole magnets, four dipole magnets (one horizontal, two vertical and one extraction) and four steering / correction coils for electron beam transport line. All power supplies are current regulated. An indirectly heated cathode requires a high voltage emitter power supply and a filament power supply for generation of electrons in microtron. Brief specifications of these power supplies are listed in the following table:

Two-switch forward converter topology is used for quadrupole power supplies and cathode power supplies. The scheme for correction coil power supply is same as quadrupole magnet power supplies, in addition a polarity change-over switch is used. Power supplies for HBM, VBM1, VBM2 and extraction magnet use the forward converter as a pre-regulator for transistor series pass regulator. Cathode emitter power supply uses two-switch flyback converter. A true-bipolar, two-quadrant power supply required for steering coils is developed using full-bridge converter.

Power supplies for RTM

Various power supplies have been developed for Free Electron Laser. The salient ratings of these power supplies are summarized in following table.

The quadrupolepole magnet power supplies and solenoid magnet power supplies are developed using series-pass linear regulator. MOSFET is used as the series-pass regulator. The dipole magnet power supplies are developed using two-switch forward converter switching at 100 kHz. Use of planar transformer and non-dissipative snubber are the features of these power supplies. Microprocessor based front panel control and display was implemented in one of the power supplies.

Power supplies developed for free electron laser

 

A training system for superconducting magnets has been developed. Two power supplies for superconducting magnets were developed. A 3V/1200A power supply is a pulse-width-modulated SMPS operating at 100 kHz. The 5V/1200A power supply was developed using thyristorized rectifier with active filter. In addition, control electronics for computer controlled data acquisition system, contact resistance measurement system for superconducting cable joints and superconducting magnet resistance measurement system with persistent current switch was also developed as the part of the system.

This variable amplitude saw tooth current (peak ±10 A) controlled power supply works in a wide range of frequency where ramp-up time can be varied from 20 to 2000 ms. The ramp-down or reset time is fixed and it is less than 2 ms. The power circuit is designed in such a way that a 80 V power supply is sufficient for complete range of operation. During reset time the stored energy of magnet is transferred to a storage capacitor and used for current reversal in the magnet.

Superconducting wigglers are planned in Indus-1. Power supplies to energize these magnets are designed, fabricated and tested .The ratings are 3V/130A, 3V/260A, 3V/390A with current stabilities of ± 0.05%.

Modular Magnet Power Supplies for CUTE-FEL Beam Line and Photocathode Gun Based LINAC

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DC current-controlled power supplies are developed for application in CUTE-FEL beamline at BP&FEL Lab, RRCAT and photocathode gun based linac being set up at Radiation and Photochemistry Division, BARC. In all, 29 power supplies for various magnets are developed. Power supply design is standardized for output ratings up to 20 A and 325 W on a standard 6U card with full-function feedback control and local-remote operation interface electronics on the same card. The power converter is an off-line SMPS circuit using two-switch forward converter, which is chosen in the reported application for its simple configuration, ruggedness, high efficiency and compact size. The specifications of magnet load and the power supply are summarized in the following table. Required output current stability is ±1000 ppm for all the supplies. Although, terminal specifications are different for all magnets, required power supplies are grouped into three ranges, namely, 12 A/3 V, 12 A/5 V and 12 A/26 V. Individual power supply cards can be configured for series-parallel operation to increase output power rating.

QP: Quadrupole magnet; SC: Steering coil; EA: Energy analyzer.
*: Terminal voltage includes the cable drop.