Sequence control of small-scaled ITER Power Supply for reactive power compensation

Abstract

A technology based on thyristors will be used to manufacture the super-conducting coil AC/DC converters because of the low ratio of cost over installed power compared to a design based on GTO or similar technology. But phase-controlled converter suffers from fundamental disadvantage. They inject current harmonics into the input ac mains due to their nonlinear characteristics, thereby distort the supply voltage waveform, and demand reactive power from the associated ac power system at retarded angles. To overcome this disadvantage, in the case of two series converters at the DC side, connected to the same step-down transformer, apply for the sequence control. It is the most simple and efficient way to reduce the reactive power consumption at low cost. Analytical sequence control algorithm is suggested, the validity of the proposed scheme has been verified by experimental results with the small-scaled International Thermonuclear Experimental Reactor (ITER) Power Supply to minimize reactive power consumption.

Control strategy optimization for energy efficiency and harmonic mitigation in multi-series converters

“…Based on formula (15), the effective value of the primary current (I A ) can be calculated by formula (16).…”

“…So it is necessary to minimize the electrical energy loss during AC/DC conversion. In recent years, sequential control has been used for multi-series converters to reduce reactive power consumption [14][15][16]. Although reactive power was saved to some degree and the power factor was partially improved by this technique, the converter's current distortion becomes more serious.…”

On the Sequential Control of ITER Poloidal Field Converters for Reactive Power Reduction

“…Once the firing angle of a six-pulse converter module is fully advanced or fully retarded [9] , it means that this converter will not consume reactive power, only consume or regenerate active power from or to the grid. The power diagram of the reactive power consumption is shown in Fig.…”