Harmonic Compensation and Load Balancing Using Cascaded H- bridge Multilevel Inverter in High Voltage Systems

This paper presents detailed modeling and simulation of a compensator for Load balancing and harmonics Compensation based on a five-level cascaded H-bridge multilevel voltage source inverter. This type of compensator, which is installed in parallel with the load, is usually referred to as the shunt active power filters (APF). Nowadays use of high voltage non-linear loads are widely used in industrial and commercial applications and elimination of harmonics in HV system has become an important aspect. Implementation of multilevel inverter (MLI) as compensator in HV system eliminates use of bulky and high cost transformer.The compensation process is based on concept of p-q theory, which is comprised of positive sequence voltage and instantaneous real-power theory. The controller method successfully eliminates harmonics even the supply voltage is distorted. The Phase Shifted Carrier PWM (PSCPWM) technique is used to generate firing angles to cascaded H-bridge multilevel inverter (CHBMLI) switches which reduces the individual device switching frequency.The distribution network which supplies mixed linear and non-linear loads and employing MLI is simulated by MATLAB/SIMULINK software. The simulation result validates the proposed control method in high voltage system. Keywords-Load Balancing, Harmonic Compensation, Multilevel Inverter, Active Power Filter, Phase Shifted Carrier PWM, Instantaneous PQ Theory, High Voltage Systems.