Research and Design of Misalignment-Tolerant LCC-LCC Compensated IPT System With Constant-Current and Constant-Voltage Output

It is well known that loads of inductive power transfer systems are often energy storage devices. The major benefit of an LCC-LCC compensation topology is that without the additional compensation elements and control methods, the load-independent constant current (CC) and constant voltage (CV) outputs, required by energy storage load, can be achieved at different resonant frequencies. However, the misalignment between two coils at the transmitting and receiving sides is inevitable and can lead to the variation of the resonant frequency in CC or CV output. Therefore, a unique design approach to the LCC-LCC compensation topology is proposed in this article. With the presented method, the resonant frequency, at which load-independent output characteristics can be also implemented, is constant and unaffected by the coupling coefficient, whether in CC mode or CV mode. Furthermore, the transmission gain, which is only impacted by the coupling coefficient, can be conveniently modified by the conventional phase shift control in two modes. Finally, a 120-W prototype is designed to verify the validity of the theoretical analysis. The output current and output voltage fluctuate by only 2.4% and 1.0% in the coupling coefficient range from 0.23 to 0.3 and the large load range, according to experimental results.