The Ki Cordless Kitchen standard

The Wireless Power Consortium (WPC) has developed the Ki Cordless Kitchen standard for cordless kitchen appliances, from simple juicers to blenders, kettles and other appliances that require up to 2.2 kW of power. This presentation will go into further depth about the development of smarter and more convenient high‑power cordless appliances enabled by the Ki standard, focusing on coil design, coupling factors, resonant inverter topologies and dynamic control strategies that engineers can apply in real kitchen environments.

Because of the different countertop thicknesses, the distance between the transmitter coil in the countertop and the receiver coil in the kitchen appliance ranges from 15 to 40 mm. The diameter of a receiver coil can range from 8 to 18 cm, resulting in a coupling factor range between the transmitter and receiver coil from 0.15 to 0.75! To meet the requirements for EMC and efficiency, so‑called load resonant inverters are applied. To cover the relatively large power and coupling factor range, duty cycle control, frequency control and burst‑mode control are used in the power controller.

The standard is supported by leading corporations in the kitchen industry, including prominent global appliance manufacturers.