Search

The WPT system for logistic robots has the problems of large fluctuation of charging power and low efficiency due to the change of its position. Based on the principle of parity time symmetry, an omnidirectional and efficient wireless power transfer system for logistic robots is proposed. Firstly, the coupling coefficient of two planar spiral coils in different relative positions in space are studied. Then, a time-varying coupled-mode model of the WPT system based on the offset angle of the receiver coil is established, and its working principle and characteristics are analyzed. As long as the coupling coefficient satisfies certain conditions, the output power and efficiency of the system are always keeping constant. Finally, the proposed model is experimentally verified. The measured results show that the WPT system proposed can realize stable 150W power transfer with constant transmitting efficiency of more than 90% for a logistic robot within a confined three-dimensional space around the charging station, which are provided to further verify the correctness of theoretical analysis.

The prospect of using robots in warehouses or supply chain processes is increasing due to the growth of the online retail market. This logistic robot is available in the market and uses a battery as energy storage device. However, this battery is large and heavy. Therefore, it needs a long recharging time. Dynamic Wireless Power Transfer (DWPT) can be an alternative to the conventional charging system because of its safety and flexibility that enables in motion charging. DWPT reduces the battery requirement size and capacity. Hence the stored energy can be used effectively for load transportation. A compensation with an inductor and two capacitors in the transmitter side, and a series connected capacitor in the receiver side which is named LCC-S compensation type has the capability to maintain the transmitter current with a fixed frequency operation. It provides less variation of the output voltage in response to the load variation. Moreover, the compensation of the receiver side uses only a single series capacitor which is low-cost. The analysis, modeling, and design procedures are discussed in this paper as well as the hardware implementation and verification of a 1.5 kW maximum power DWPT. The experiment shows the capability of the proposed system and shows maximum efficiency can reach 91.02%. [ABSTRACT FROM AUTHOR]

The prospect of using robots in warehouses or supply chain processes is increasing due to the growth of the online retail market. This logistic robot is available in the market and uses a battery as energy storage device. However, this battery is large and heavy. Therefore, it needs a long recharging time. Dynamic Wireless Power Transfer (DWPT) can be an alternative to the conventional charging system because of its safety and flexibility that enables in motion charging. DWPT reduces the battery requirement size and capacity. Hence the stored energy can be used effectively for load transportation. A compensation with an inductor and two capacitors in the transmitter side, and a series connected capacitor in the receiver side which is named LCC-S compensation type has the capability to maintain the transmitter current with a fixed frequency operation. It provides less variation of the output voltage in response to the load variation. Moreover, the compensation of the receiver side uses only a single series capacitor which is low-cost. The analysis, modeling, and design procedures are discussed in this paper as well as the hardware implementation and verification of a 1.5 kW maximum power DWPT. The experiment shows the capability of the proposed system and shows maximum efficiency can reach 91.02%.