A PLL-less Vector Control technique for the single-phase Grid connected inverters

Abstract

The control of single-phase Grid connected inverters by Vector Current Control Direct Quadrature (VCC DQ) method is a well-known technique. However, the presence of a Phase-Locked Loop (PLL) affects the dynamic response of the system. This paper proposes a PLL-less Vector Control (PLVC) method in which a single-phase Grid connected inverter is controlled without any PLL. Hence it reduces the complexity and computational burden during implementation on the Digital Signal Processor (DSP) controller as well as the natural coupling of PLL and current controller. The mathematical modeling and controller design for the PLVC method is described. A 5 kW single-phase Grid connected inverter simulation model and a 150 W hardware prototype with TI F28379D processor are developed and tested under steady-state at rated power condition and dynamic conditions like instant variation in the reference powers. Also, the robustness of the controller is tested under adverse conditions voltage sag, swell at the instant of distinct phase angles and frequency deviation also.