Technical Note ESRF-CERN: NEW TGC CONTROL WITH THREE-PHASE SYNCHRONISM

MARIO BENEDETTI; OLIVIER GOUDARD; NICOLAS WASSINGER; GUSTAVO UICICH; MARCOS FUNES; SEBASTIAN MAESTRI; ROGELIO GARCIA RETEGUI; IGNACIO CARUGATI; CARLOS ORALLO; JOSE LUIS GOMEZ COSTA

2014-01-01/2014-02-19

1-135

Electrónica

Energia-Electrica

In this report, a digital high-precision open-loop thyristor firing system based on a digital three-phase mains synchronized phase-locked loop (PLL) is presented. This work is organized in five chapters. In chapter one, controlled AC/DC line commutated rectifiers are presented. Average output voltage, small-signal gain and output voltage ripple are analyzed for both rectifier/inverter and freewheel structures, used in continuous conduction mode. Moreover, the converters dynamics are evaluated leading to a mathematical model which is useful for the conception of the closed loop control. In chapter two, the firing-system operating principle is described. Several open and closed loop methods are presented and their main advantages and drawbacks are evaluated. Considering that, an open-loop digital technique with an embedded PLL, using an external look-up table to compensate for the non-linear static gain results the best solution. Finally, a reduced-complexity high-dynamics 6, 12 and 24 pulses firing-system implementation is proposed. In chapter three, the implementation of an all-digital high-speed closed-loop thyristor firing system TGC based on the Cassel-Ainsworth technique is presented and compared whit the analog one. Different aspects associated to digital implementations, like sampling frequency, synchronism and finite word-length are analyzed. Experimental results obtained of both analog and digital systems are discussed. -/- Esta Nota Técnica está asociada al Servicio Científico-Tecnológico denominado "Development and supply of a digital control for ESRF main power supply - Phase 1- Part 2". La fecha de inicio de este trabajo es 11/2013 pero fue modificada para ser tenida en cuenta en el informe anual 2014 como me fue indicado por el personal de CIC informes desde el sistema de consultas SIGEVA.