Current sensorless control algorithm of DSTATCOM for power quality improvement

This paper presents a current sensorless based control algorithm of a DSTATCOM (Distribution Static Compensator) employed in three phase distribution system with a neutral conductor. The control algorithm emulates the load and DSTATCOM collectively as a balanced resistive load for the supply system. This feature allows the algorithm to estimate the current in real time and eliminates the current sensor requirement. The algorithm is derived for a modified topology of DSTATCOM in the system which advantages are described in this paper. The algorithm is simple and can be implemented with much lesser calculation than the other complex algorithms and it has an appreciable cost impact due to elimination of costly closed loop current sensors. This algorithm is effective in mitigating the various power quality problems like neutral current compensation, reactive power compensation, harmonics currents mitigation and load balancing in the distribution system.