Control of balance of arm capacitor voltages in STATCOMS based on chain links of H bridge modules

摘要

An optimized structure of an arm capacitor voltage balance controller based on chain links of the H-bridge module that achieves enhanced performance of an arm capacitor voltage balance control in all operational conditions, even with highly dynamic loads. Such a controller has application in three-phase STATCOM converters, and may be structured so as to seamlessly integrate feedforward and feedback controls with inverse maps used for calculation of the zero sequence reference voltage injection(s) (for star and delta STATCOM topologies).

主权项

1. A method of controlling a converter having three-phase arms, the method comprising:
detecting the voltages and the currents of the converter; decomposing the detected voltages and the detected currents into symmetrical components; performing feed-forward calculations of a power imbalance space vector using the symmetrical components; performing feedback balancing of arm dc bus voltages; calculating at least one of a zero sequence reference voltage and a zero sequence reference current based on a universal inverse map developed between components of the power imbalance space vector and the symmetrical components; and injecting a zero sequence reference signal to the three-phase arms based on the calculated at least one of the zero sequence reference voltage and the zero sequence reference current.