Applications in Other Branches of Power Electronics

The digital-control theory is applied in other branches of power electronics, such as, power factor correction (PFC), static compensation (STATCOM), flexible AC transmission system (FACTS), reactive power (VAr) compensation, and power quality control (PQC). This chapter describes digital-control theory that is being applied in some branches of power electronics. Reactive power has no real physical meaning, but is recognized as an essential factor in the design and good operation of power systems. VAr compensation or control is an essential part in a power system to minimize power transmission losses, to maximize power transmission capability, and to maintain the supply voltage. The chapter talks about power-systems analysis, power-factor correction, and static compensation (STATCOM). The staircase PWM is widely used in STATCOM because GTOs with lower-switching frequency are employed as switches in such applications of high power and high voltage. The vector control based on synchronous frame transform has been used successfully in STATCOM to regulate reactive power and reduce negative-sequence component of the bus voltage. This chapter deals with how the vector control and staircase modulation are combined to reach the control aims.