Total Harmonic Distortion and Output Current Optimization Method of Inductive Power Transfer System for Power Loss Reduction

Abstract

Inductive power transfer (IPT) system is widely used in material handling. A typical structure of the system takes an H-bridge inverter with an inductor-capacitor-inductor (LCL) resonant filter to realize a constant track current supplying changeless energy to the second side. However, the output voltage total harmonic distortion (THD) of the inverter increases, which causes the increase of output current circulation, when using voltage width control method to eliminate source voltage fluctuating. Therefore, a two-stage converter is proposed to optimize the output current circulation. The two-stage IPT system is composed of a boost converter cascaded with an H-bridge resonant inverter. The boost converter is employed to provide a higher and stable DC bus voltage. The H-bridge resonant inverter operates in a fixed width with a constant switching frequency. With the proposed topology, the THD of the high frequency voltage maintains the minimum value to realize minimum output current circulation in the LCL filter. The soft switching is realized to reduce the losses. Furthermore, expressions of coil and track model are presented by combining the theoretical analysis and finite element analysis (FEA). The experimental results show that over 76.6% efficiency is demonstrated in conditions of an 800 W load at the 14% source voltage fluctuation and the maximum efficiency was 78.6 %. The range of efficiency variation was 2% compared to a full-bridge system with voltage pluse-width control of which was 4.6%. INDEX TERMS Inductive power transfer (IPT), material handling, THD optimization, soft switching, finite element analysis (FEA).

Enhancement of Wireless Power Transfer for Automated Guided Vehicles Considering Disturbance Suppression

“…Analysis results of (17) indicate that the increment of total impedance ZinV promotes the suppression capability of higher order harmonics. It is also noted that the ZinV is mainly affected by the inductance Ls rather than the Lr, and equation ( 14) reveals that the irV is related to impedance Zc.…”

“…It is also noted that the ZinV is mainly affected by the inductance Ls rather than the Lr, and equation ( 14) reveals that the irV is related to impedance Zc. Through the aforementioned theoretical derivations, they conclude that the increased values of inductance Lr and coil Ls are helpful to suppress harmonic disturbances based on the analysis results of equations ( 8) and (17).…”

“…Later on, the development of analytical methods and corresponding strategies were subsequently reported. Some studies quantified the impact of high-order harmonics based on the efficiency and circuit loss, while other studies focused on the investigation of control strategy, parameter tuning, and improved compensation [17][18][19]. The utilization of frequency modulation method was also reported to manage this issue [20][21][22][23].…”

Printed Circuit Board Coils of Multitrack Litz Structure for 3.3-kW Inductive Power Transfer System

“…High-power WPT systems have advanced significantly thanks to efforts to optimize the design of magnetic devices, power electronic stages, control strategies, communication protocols, and other related fields, [20], [21], [22].…”