A Novel Fast Acting PI based Multilevel DSTATCOM

The instantaneous response of the distribution static compensator (DSTATCOM) is very important while compensating rapidly varying balanced, unbalanced and nonlinear loads. Any change in the load affects the dc-link voltage directly. The proper operation of DSTATCOM requires variation of the dc-link voltage within the prescribed limits. Conventionally, a proportional-integral (PI) controller is used to maintain the dc-link voltage to the reference value. It uses deviation of the capacitor voltage from its reference value as its input. However, the transient response of the conventional PI dc-link voltage controller is slow. In this paper, a fast-acting dc-link voltage controller based on the energy of a dc-link capacitor is proposed. Mathematical equations are given to compute the gains of the conventional controller based on fast-acting dclink voltage controllers to achieve similar fast transient response. The detailed simulations are carried out on MATLAB environment to validate the proposed