A New Design of UPQC-Based Hybrid Multi-Carrier Modulation for Transformer Less Grid Connected PV-Based Active Power Filter

Abstract

In recent times, there has been a growing concern over the augmented power consumption, leading to a pressing need for compensating devices to maintain power quality in grid-connected systems. One extensively employed solution is the Unified Power Quality Conditioner (UPQC), which incorporates both shunt and series active power filters (APFs) connected through a DC-link capacitor. However, traditional systems using compensating devices can be costly and cumbersome, often relying on transformers to interface with the grid. To address these drawbacks, this report proposes a transformer-less networking approach using a multi-level inverter (MLI) that reduces the number of switches in the shunt and series APF. To enable the efficient operation of the MLI in UPQC, the report utilizes Synchronous Reference Frame Theory and Hybrid Multi-Carrier Pulse Width Modulation (H-MCPWM) techniques for reference signal generation and gate control, respectively. MATLAB/Simulink simulation version 2019a is employed to validate the performance of the proposed system, along with a hardware prototype featuring a motor load. A key aspect of the investigation involves conducting harmonic analysis for various modulation indices with a non-linear load. The resulting data is then compared to the outcomes of the conventional model. By exploring this approach, the report aims to showcase the viability of the transformer-less networking of MLI in UPQC, thereby paving the way for more cost-effective and efficient grid-connected systems with improved power quality.