Power converters for other applications


Apart from development of magnet power converters for Indus-1, Indus-2, IRFEL and FAIR projects respectively, power converters have also been developed for other applications by SMPCS.

1. Laser Diode Drivers
2. Sine Wave Current Source for Study of Superconducting Materials
3. Development of two quadrant power converter for solenoid coil in atom cooling experiment
4. Ultra-capacitor Charger Power Converter
5. Development of High-Voltage DC Power Converter

Laser Diode Drivers

A 40 A, 2.5 V dc current controlled power converter has been developed for laser diode for laser marking system. The salient features of power converter are: small size, light weight, low cost, simple configuration, high reliability and ruggedness. It is based on two switch forward converter topology operating at 100 kHz. The power converter has been successfully integrated and tested with the laser marker system.



In addition to the above, an 80 A, 6 V dc current controlled power converter has also been developed for energizing laser diode for laser marking system. The scheme used is 2L-ISIPO (Interleaved Series Input Parallel Output Two Switch Forward Converter). The salient features of these power converters are: small size, light weight, low cost, simple configuration, high reliability and ruggedness. The power converter is developed using interleaved series input parallel output forward converter topology using MOSFETs operating at 100 kHz.



Sine Wave Current Source for Study of Superconducting Materials

A variable frequency ac current source is required to generate an alternating magnetic field of about 1 to 2 Oersted to study the response of various magnetic and superconducting materials at various frequencies. The current source is rated to provide the load a constant sinusoidal current at the output with the peak current and voltage ratings of 100 mA, 63 V respectively and frequency ranging from 1 Hz to 100 kHz. It is based on improved Howland current source and is developed using APEX PA 85 power operational amplifier. The current source can be operated with local as well as remote reference source with 1 V of peak reference voltage corresponding to peak output current of 100 mA.



Development of two quadrant power converter for solenoid coil in atom cooling experiment

A 50 A, ±226 V current regulated bipolar power converter has been developed at SMPCL, PCD, RRCAT to energize the solenoid coil in atom cooling experiment. It is based on two quadrant switch mode converter topology operating at 25 kHz. Specialty of this converter lies in its ability to generate fast rising and falling current patterns at inductive load in the output with rise and fall times of the order of 1 ms each. This is achieved by incorporating a feed forward loop in the control circuit along with the feedback control scheme. The feed forward loop is designed so that it operates only during rising and falling durations of the output currents by responding to a calibrated remote reference. Various protection features like over current, over voltage, over temperature, IGBT faults and MPCB interlock have been incorporated in design to trip the converter in case of faults.



Ultra-capacitor Charger Power Converter

A compact, scalable, standard 4U card sized constant-current Ultra Capacitor Charger (UCC) using high frequency, soft-switching resonant converter has been developed. Ultracapacitors, also known as Supercapacitors, offer many advantages over batteries such as large number of charge-discharge cycles, low ESR, high efficiency, high power density and low heating. Therefore, ultracapacitors are being increasingly used in portable electrical and electronic devices and transportation in conjunction with batteries. It is hoped that in near future, automotive industry will deploy ultracapacitors as a replacement for batteries. Another advantage of ultracapacitor is its ability of being charged quickly. The power converter is an inherent current source with passive output voltage clamping capable of direct parallel operation (to increase output current) without any current sharing control. Required control and interface is simple and therefore rugged for industrial application. The developed charger has been designed for ± 48 V DC input, 10 A output current, 15 V maximum charging voltage and tested with 58 F ultracapacitor. The same card can easily be re-configured for other specific application requirements.





Development of High-Voltage DC Power Converter

A crowbar-less high voltage DC power converter of 20 kV / 1 A output rating has been developed using LCL-T resonant converter, which exhibits constant-voltage to constant-current conversion characteristics, which in turn is advantageous for phase-shifted parallel operation of modules without any need for current equalization feedback control and safe operation under arcing and partial discharges. The power converter is designed to be a three-phase LCL-T resonant converter which is free-running at constant (resonant) frequency. The output is controlled by controlling the input dc voltage of the resonant converter using another front-end DC-DC converter. The power converter has been tested to 20 kV successfully and under simulated arcing conditions. The performance is in conformance with the analytical predictions.