Research on modular STATCOM based on dynamic reactive current detection method

Modular circuit has become the new converter topology widely used in the field of UPS, high power source, HVDC and other areas. Based on the modular voltage sourced converter, modular STATCOM has been discussed, which has the advantages of better compensation and high dynamic response. Circuit topology and work principle of the proposed device are analyzed. With the study of single-phase reactive compensation system, a new dynamic reactive current detection method is studied. The reactive current amplitude is calculated directly from the instantaneous samplings of voltage and current by means of mathematic relation of trigonometric function. Control strategy of STATCOM is given and DC capacitor voltages are controlled to operate under balanced condition. The correctness and validity of this system are proved by test results.