The structure of a contactless energy transfer system (CET system) is shown in Figure 1. Inductive energy transmission is technically possible with high efficiency and a low coupling factor of the coil system, provided the reactive power of the system is compensated. In inductive transmission, the inductances of the transmission coils are compensated by capacitors. The capacitors can be arranged either serial (s) or parallel (p) to the coils. Basically, the following compensation topologies can be distinguished when using one capacitance each for the primary side (1) and the secondary side (2):
- 1s2s topology
- 1s2p topology
- 1p2p topology
- 1p2s topology
The selection of the topology used to compensate for the CET system depends on the desired system behavior. For example, a voltage or a current source behaviour can be realized by a suitable selection on the load side. Figure 2 shows the system behavior in terms of voltage transfer function and input impedance for the 1s2s system.