Active power control of direct current smart house using electric vehicles and controllable loads

DC smart house is receiving attention as means for the management of electric power. Since many domestic appliances are also DC devices, the DC smart house can also reduce conversion losses. Recently, the increased introduction of residential photovoltaic generators (PV) has been remarkable. However, since the output power of PV fluctuates according to weather conditions and is commonly allowed to flow into the power grid, it is difficult for the supply side to balance supply and demand. The purpose of this study is to prevent the fluctuations of the PV output power connected to the DC smart house from flowing into the power system. This paper proposes compensation methods for fluctuations in the output power of the PV as well as those caused by consumption power of uncontrollable loads. The proposed scheme achieves a stable constant active power interconnection point between the smart house and the grid by cooperative operation of Electric Vehicle (EV) and Electric Water Heater (EWH). The control scheme of both the EV and the EWH uses the H∞ control method. H∞ control improves the control performance because the gain can be regulated according to the frequency domain. The proposed scheme is tested by comparing with two other cases, of which the control group comprises no-controller for each device and Proportional-Integral (PI) controllers for each device. In the no-control scenario, these devices follow a randomly generated load profile. The effectiveness of the proposed method is verified by simulation results in the MATLAB/Simulink® environment.