Load Segment Tracking Control of IPT System Based on Power Efficiency Optimization

Abstract

In the induction electric energy transmission system applied to fix point charging of vehicles, the mutual inductance change caused by position deviation or air gap change, and the equivalent load change caused by power demand change will make the output power and efficiency fluctuate, thus affecting the output stability of the system. In order to ensure the reliability of the charging process of the system and at the same time have a strong power output capacity, this paper proposes a load segmental tracking control strategy based on the optimal power efficiency. This control strategy adjusts the equivalent load to track different power efficiency indicator curves according to different mutual inductance states of the system and power demand when the vehicle is static charging, so that it can always maintain the optimal power efficiency state according to different charging conditions and improve the system performance. Finally, simulation and experimental verification are carried out under different states of mutual inductance. The results show that this method can achieve the equivalent load segmental tracking under different mutual inductance states, and always maintain the optimal power efficiency output. INDEX TERMS Efficiency, inductive power transmission, load tracking, optimization, power.

A Simple Method to Determine the Performance of Two-Coil Wireless Power Transfer Systems without Direct Output Measurement

“…In fact, it was demonstrated that typical two-coil WPT systems have unique set of * , * and as function of 12 , and as the relation between 12 and * is univocal, determining * , means that both * and can be determined. It was also shown that the influence of can be calculated comparing it with 2 so that the performance of practical WPT systems can be conveniently represented by * and/or (see (13) and (14)). The diagram * versus * and illustrates the proposed method (see Fig.…”

“…Note that in practice as 2 / decreases, * approaches * as well as approaches , whereas, * is not influenced by the relation 2 / . Therefore, multiplying (12) by /( 2 + ) and using (13) and (14) it can be written * = 4 * ,…”

“…On the other hand, innumerous combinations of 12 − − 1 can yield a given value of 12 . However, the absolute value of is determined, given a voltage source with amplitude " " and a 12 value, by 1 (see (5)) and, from the * and values, 2 / determines * and/or (see (13) and (14)), respectively. Although the presented analysis was developed for both source and load as series circuits, evidently it can adapted to most of the other configurations (series-parallel, etc., see for example [23]) calculating the equivalent series circuit.…”

“…The data via * were obtained dividing 1 by 1 and applying (11) and (12) to obtain and * , respectively. These values of and * and those of 2 / according to the selected were used in (13) and (14) to compute and * , respectively. Fig.…”

“…Perhaps because of their increasing importance, a lot of research efforts have been devoted to the improvement of the overall system efficiency and/or power transfer capability [7]- [13]. The WPT system's efficiency ( ) can be defined as the power delivered to the load circuit ( ) divided by the total power supplied by the source ( ), whereas its power transfer capability ( * ) can be defined as divided the maximum ideal amount of power which can be delivered to the load circuit [11].…”