Energy Flow Path Planning and Multiload Constant Voltage Outputs in Domino WPT System Based on Current Phase Configuration

Cross-coupling among the domino coils complicates the energy flow paths and prevents the multiload constant outputs in wireless power transfer (WPT) system. To overcome this problem, the current phase of the domino coils is first analyzed so that the impedance relationship of cross-coupling in its corresponding coil loop is found. The analytical formula for computing the resonant compensation capacitance is then derived according to the current phase configuration with 90 degrees of decline gradient. It can achieve the load-independent zero phase angle and constant outputs simultaneously in a single-energy flow transmission mode. Then the domino coils are further extended to the transmission mode with multienergy flow paths that can be planned by configuring the current phase. Finally, a general capacitance calculation method is proposed for different energy flow path planning. Prototypes of seven-coil domino system and six-coil domino system are constructed. Experimental results show that seven-coil domino system with the single energy flow path achieves the constant voltage of 29.55 V and a dc–dc efficiency of 83.69%. Six-coil WPT system also has the constant outputs of 21.34 V and 32.31 V by planning the dual energy flow paths, with a dc–dc efficiency of 79.68%.