Smart Electric Vehicle Charging System with Flexible Charging and Voltage Stabilisation Service for Australian Household Network

As the number of electric vehicles (EVs) is rapidly increasing, household chargers are attracting more users because of cheaper electricity rates and easier accessibility. This, however, will inevitably increase the power demanded from the low voltage network and potentially make more impact on the grid voltage. This paper proposes a smart bidirectional charger that is facilitated with a voltage supportive control to meet Australian Standard AS/NZS 4777.2 which specifies the expected performance and behavior of inverters for bidirectional energy flows at low voltages. The voltage supportive control minimises the impact of the charging operation on the grid, while also supporting the grid voltage from further deviations. The proposed charger is also able to provide flexible charging based on the household load consumption. As a result, higher charging power is enabled during the off-peak hours, and less power is allowed during the on-peak hours. This functionality is beneficial for the residential building networks which were not initially designed for high power demand, and due to thermal and safety reasons, charging an EV is more challenging. The proposed system is designed and simulated, and different case studies are shown to validate its effectiveness.