Requirements on Power Electronics for converting Kitchen Appliances from AC to DC

The main power source for kitchen appliances for cooking and heating in Europe is natural gas. Since fossil fuels are limited, an energy transition is taking place from fossil fuel supply towards renewable energy such as solar and wind power. Kitchen appliances for cooking and heating have to be converted towards the use of electrical energy. Although many kitchen appliances are available for electrical energy supply, a transition to a DC grid would have benefits regarding control, earth leakage protection and peak power usage. Congestion management is solved via droop control. The bandwidth of droop control in DC grids is significantly higher compared to droop control in AC grids. Droop control enables load sharing during peak power demand. Earth leakage protection in an isolated grid enables early detection of earth faults, before they become critical. Furthermore short circuit protection in a DC grid is implemented via a predictive rate of change of current di/dt measurement, isolating a fault before the short circuit current can grow. The inrush current that exist when directly connecting the AC appliance to a DC grid, can be avoided by using a programmed current limiter which controls the level of the input current. Secondly this current limiter can be used to control the power level in appliances where current control is enough to control the application, such as the resistive heater in an oven.Examples are given on the appliance of a inductive cooking and controlling the heater in an oven.