Implementation of harmonic control for a 3-phase 4-wire inverter with harmonic-loaded neutral

The paper presents a 3-phase 4-wire VSC with a single-phase unbalanced load. The voltage control loop is investigated in order to attenuate harmonics of the load voltage. The output voltage is transformed into DC quantities to control the inverter. This kind of inverter can be a good choice for the applications with hybrid power system based on renewable energy used to supply unbalanced harmonic loads. The fourth leg allows controlling the zero sequence components of the system. The paper consists of two main sections. The simulation is on the basis of MATLAB and implemented by DSP-programming. Simulation results are compared with experimental results for a prototype inverter to verify the validity of the proposed control strategy.