A Novel Orthogonal Current Decomposition Control for Grid-Connected Voltage Source Converter

Grid-connected voltage source converter is used to control the flow of active power from renewable energy sources with several functionalities, such as harmonic mitigation, reactive power compensation, and power factor improvement. The reference current calculation and its accuracy decide the performance of the control algorithms during harmonic disturbances. Fundamental signal extraction techniques are utilized to overcome the disturbances present in the system voltage and current. This paper presents a novel orthogonal current decomposition control for load current decomposition into active and reactive components. These current components are obtained through character of orthogonal vector in the inner product space. The block diagram of the proposed technique is implemented with the help of adder, multiplier, and windowed integrator. Phase voltage and load current for each phase are used as inputs to this functional diagram for getting desired fundamental active current signal. Subsequently, adjustable dc-link voltage control is also presented to diminish the switching losses in the converter and to avoid the false tripping of the grid-connected system during susceptible grid conditions. The proposed control technique is simulated in MATLAB/Simulink and verified through developed hardware prototype using ARM Cortex M4-based microcontroller (STM32F407VGT6) using Waijung environment.