Implementation and evaluation of an IPT battery charging system in assisting grid frequency stabilisation through Dynamic Demand Control

The paper presents a hands free Inductive Power Transfer (IPT) system for charging Electric Vehicle (EV) batteries using a technique called dynamic demand control (DDC). A typical IPT system comprises a power supply, a pair of magnetic pads for wireless power coupling and a power regulator to drive the load as required. DDC enables suitable domestic appliances to assist grid stabilisation by adjusting their power demand according to the utility frequency variation. This paper explains the conceptual design of a wireless power charging system that includes DDC and details the experimental set up for an emulated erratic isolated power network which combines a variable speed drive, an induction motor and an AC generator. The measured performance of the emulated power network generator frequency without DDC varies between 47 Hz to 53Hz, but this same network frequency is maintained within a preset window of 49.5 Hz to 50.5 Hz when DDC is activated in the IPT battery charging system. Consequently EV charging systems employing DDC control could potentially act as a grid stabilising load, enabling increased penetration of fluctuating sources of energy (such as wind) in the generation mix..