Operating Low Frequency Wind Power System in Variable Voltage Mode

Most of the current research on low frequency wind power systems (LFWPS) directly combines the two main technologies of low frequency AC transmission and variable speed constant frequency (VSCF) wind energy conversion system (WECS), where the low frequency transmission uses a constant voltage to transmit power. This paper proposes a variable voltage low frequency wind power system (VV-LFWPS) scheme, in which the wind farm side voltage provided by the onshore ac–ac station is dynamically varied, with the voltage decrease with decreasing wind speed and increase with increasing wind speed in general. This paper also compares the losses and the fault ride through performance of VV-LFWPS and constant voltage LFWPS (CV-LFWPS). The electromagnetic transient simulation shows the superiority of VV-LFWPS.