DSTATCOM Using Matrix Converter for Reactive Power Compensation

A DSTATCOM is a fast acting shunt connected custom power device used in the distribution system. The voltage source converter(VSC) or current source converter is an important element in it. For high-voltage distribution system, the DSTATCOMs are designed using a two-level VSC and the transformer at the output side to meet the desired voltage profile. For high power application, the VSCs are connected in parallel to the DC bus. This type of connection requires a transformer with multiple secondary windings, which increases the complexity of the power system. Further, the transformer increases the overall cost and losses in the system and may saturate when the load draws any DC current. The efficiency of the system is also low due to the increased switching losses. Generally, the use of a two-level inverter requires a filter circuit for reducing the THD at the output. To overcome these drawbacks multilevel inverter is used. In a multilevel inverter, number of switches operating at any time is more than three, which increases the switching losses. Hence a matrix converter is operated as a multilevel inverter and matrix converter based DSTATCOM is proposed. Hysterises current control(HCC) switching algorithm is used in which the number of switches conducting at any time is three in the matrix converter and is less than the number of switches conducting at any time in a multilevel inverter. This paper investigates the matrix converter based DSTATCOM for reactive power compensation in the MATLAB / SIMULINK environment.