Direct Output Voltage Control of a Static Synchronous Compensator Using Current Sensorless d-q Vector-Based Power Balancing Scheme

A new current sensorless method based on power balancing algorithm is proposed for direct output voltage control of a static synchronous compensator (STATCOM). The principal advantage of the proposed control scheme is that the STATCOM output voltage command is directly achieved via a simple algebraic algorithm using only the error signals of the AC and DC voltage regulators. As a result, complicated computations involved in the d-q current loop can be avoided. In addition, the implementation cost can be reduced to a great extent since there is no need for the current sensors. A mathematical formulation for the proposed control scheme is first described. Then the dynamic responses of the STATCOM under disturbance conditions are simulated on the Matlab/Simulmk platform. It is concluded from the simulation results that AC bus voltage can be effectively regulated by the STATCOM with the proposed control scheme.