Improved Imaginary Axis Current Estimation for Single-phase Voltage Source Converters

This paper presents an improved imaginary axis current estimation (IACE) method based on reference input for dq current control of single-phase voltage source converters (VSCs). A model is established that describes the incomplete dq decoupling of currents. According to this model, the influence of the dynamic performance of IACE methods on the current loop is analyzed. The results show that the dynamic response of the adopted IACE method slows down the current loop. To improve the dynamic performance of the dq current controller in single-phase VSCs, an improved IACE method was proposed and verified by the hardware-in-the-loop (HIL) experiment. The proposed method commits a linear transform with a simple calculation, which provides good steady-state performance and can effectively improve the dynamic performance of the current-loop.