Power Management for Multiple-Pickup IPT Systems in Materials Handling Applications

Multiple-pickup inductive power transfer (IPT) systems are popular in clean rooms and other materials handling applications. Currently, these systems use power supplies rated at or above the sum of the total pickups' rated power to prevent the system from overloading. In consequence, there is spare capacity that is not always utilized. This paper proposes a novel power management control for each of two popular load regulation methods used in materials handling applications, namely: 1) fast-switching and 2) slow-switching. The approach enables power supplies with smaller capacity to be used, without compromising system integrity and thereby saves system cost. The proposed controls have minimal impacts on the pickups' normal operation during light loading periods and heavy loading periods all pickups are affected equally. In addition, it is possible to modify the controls slightly to assign pickups with different priorities such that the normal operation of critical tasks is guaranteed. The proposed methods use the IPT frequency as the communication channel, removing the need for an extra communication system. They also require minimal adjustments to usual system configurations and can therefore be easily implemented on existing systems. Experimental results show that both proposed controls are valid under various loading conditions.