A Single-Switch IPT Driver for Unipolar–Bipolar Composite Coils Achieving Misalignment Tolerance

Misalignment tolerance is a critical performance metric for inductive power transfer (IPT) systems. Various composite coil designs, such as double-D quadrature pad (DDQP), quadruple D square pad (QDSP), and rectangular solenoidal pad (RSP), have been successfully developed to generate complementary magnetic fields to mitigate this problem. However, the inclusion of two inverters often results in increased circuit components, size, and cost, which can be drawbacks for many low-to-medium power consumer applications. This letter proposes a simple single-switch IPT driver that utilizes both fundamental and second harmonics currents to energize a set of composite coils. Using RSP as an example, the unipolar coil is excited by the fundamental harmonic as usual, while the bipolar coil is driven by the second harmonic current. This approach not only reduces circuit complexity but also simplifies the control method, eliminating the need for active detection and control mechanisms. The letter details the analysis, design, simulations, and validation process of the experiment.