Current Compensation using Modified Seven Level Multilevel Inverter and Fast Acting DC- Link Voltage Controller based DSTATCOM

Abstract — The multilevel converter has drawn tremendous interest in the power industry. The general structure of the multilevel converter is to synthesize a sinusoidal voltage from several levels of voltages. Multilevel voltage source converters are emerging as a new breed of power converter options for high power applications. These converter topologies can generate high-quality voltage waveforms with power semiconductor switches operating at a frequency near the fundamental. Among the available multilevel converter topologies, the cascaded multilevel converter constitutes a promising alternative, providing a modular design that can be extended to allow a transformer less connection. A three-phase, seven level cascaded multilevel voltage source inverter with reduced number of switches based DSTATCOM for power line conditioning to improve power quality in the distribution network is used which will compensate the distorted line current harmonics and reactive power. The reference currents for generating switching signals of multilevel inverter are obtained using Instantaneous Real Power Theory. A new dc-link voltage controller is also used which will overcome the disadvantages of conventional Proportional Integral controllers. Keywords-DSTATCOM, Instantaneous real power theory, Proportional Integral controllers, Multilevel inverter, DC link capacitor