Algorithm for Designing LC Circuits with Parallel Compensation in the Receiving Circuit for Inductive Power Systems

Algorithms based on coil geometry optimization allow increasing the resistance to displacements without complicating the design, as happens when using various forms of feedback. An essential feature of such algorithms is the need to consider the scheme of parallel or tandem compensation of reactive power in the transmitting and receiving LC circuits. In this study, based on previously proposed algorithm for systems with tandem compensation in the receiving and transmitting circuits, a new algorithm is developed for systems with tandem compensation in the transmitting circuit and parallel compensation in the receiving circuit. The algorithm being proposed considers the allowable value of coil inductance in the receiving circuit at specified values of operating frequency and balancing capacitance. The advantage of the presented design algorithm lies in the systems of inductive energy transfer developed through it with strong resistance to coil pair displacement due to the optimal coil geometry without complicating the design of the inductive energy transfer system. The developed system operates at the resonant frequency and in the region of supercritical coupling, which ensures high energy transfer efficiency and output power level. Systems design with a nominal power of 0.1 W and operating frequencies of 6.78 MHz and 880 kHz is implemented. The stability requirements for both systems are formulated as follows: ΔPL not more than 0.01 W (10% of the nominal value) for lateral displacements within 0–30 mm, i.e., at lateral displacements reaching the radius of the receiving coil. The axial distance between coils is constant and equal to 10 mm. It is demonstrated that the developed algorithm makes it possible to design the transmitting and receiving LC circuits so that the output power drop does not exceed 10% of the nominal value for displacements reaching the radius of the receiving coil. Parasitic effects not taken into account in the algorithm can lead to a decrease in the output power of the system by 3–7%, which can be compensated by increasing the supply voltage or by increasing the specified rated power by 2–4% when using the algorithm for designing the system.