The invention firstly relates to a receiver unit (200), configured to interact for wireless energy transfer with a transmitter unit (100) separate from the receiving unit, said transmitter unit (100) comprising a primary coil (L1) that can be supplied with a supply voltage (UV), wherein the receiver unit (200) comprises a secondary coil (L2) to which a DC link capacitor (CZ) and an energy storage unit (220) are connected by a power converter (210). According to the invention, the receiver unit (200) contains a device (240) for actuating the power converter (210) when a voltage is applied on the DC link capacitor (CZ) for supplying an alternating current (I) flowing through the secondary coil (L2) by actuating the power converter (210) to generate an energy pulse (EP). Secondly, the invention relates to a transmitter unit (100) configured to interact with a receiver unit (200) separate from the transmitter unit for wireless energy transfer, wherein the transmitter unit (100) comprises a primary coil (L1) that can be supplied with a supply voltage (UV). There is a device (140) in the transmitter unit for detecting a voltage (UI) induced in the primary coil when the supply voltage is disconnected from the primary coil (L1).
