A New Maximum Inductive Power Transmission Capacity Tracking Method

Abstract

In certain applications, such as IPT-based EV charger (IPTEC), any variation in alignment and distance between pickup and charger primary leads to a change in leakage and magnetic impedance magnitudes. The power transmission capacity is not always at the maximum level because of these variations. This study proposes a new low-cost tracking method that achieves the Maximum Inductive Power Transmission Capacity (MIPTC). Furthermore, in the proposed method, the exchange of information between load and source is not required. For an application such as IPTEC, the load detected by the IPTEC varies continuously with time because of the change in state of the charge. This load variation causes a significant variation in IPT resonant circuit voltage gain. However, the optimized charging output voltage should be kept constant. From the analysis of the behavior of the IPT circuit at different working frequencies and load conditions, a MIPTC operation point that is independent of load condition can be identified. Finally, the experimental results of a developed prototype IPT circuit test show the performance of the proposed method.

Compensation Topologies in IPT Systems: Standards, Requirements, Classification, Analysis, Comparison and Application

“…The maximum load power condition has different frequencies ( Table 3). For the SS compensation it is (10) [6] and (14), for the SP it is (14), for PS is (13), for the PP approximately also is (13) [41]. Consequently, according to this analysis, the SS and SP compensations can provide a constant voltage and constant current output, but operate at different frequencies.…”

“…The biggest advantage of the SS topology is the fact that the compensation capacities do not depend neither on the magnetic coupling coefficientk = M / L p • L s nor the load on the resonance frequency (1) [6], [8], [49]. To illustrate the dependence of the compensation on the coupling coefficient, it is necessary to calculate the capacitors for operation at the resonant frequency (Table 2).…”

“…On the resonance frequency, the voltage gain in PP topology is related to the load and the transformer parameters, and its gain is less than 1 for all loads. The voltage ratio presents a different value for different values of the load [6].…”

“…The series compensation requires a higher voltage and current than the parallel compensation [56].The application of the SS compensation is more expedient for a large power with variable load parameters, such as charging electric accumulators with a load of several kilowatts [6], [11], [21], [42], [57]. Also SS compensation is especially useful in segmented dynamic wireless power transfer applications, where the coupling coefficient varies with movement of the EV [7] and the voltage transferred to the secondary is very high.…”

“…The large air gap of the transformer increases the leakage of the flow and, as a result, leads to a higher leakage inductance compared to the conventional transformers. The efficiency of IPT without compensation as a rule does not exceed 50% [6]. To compensate the leakage inductance, the reactive power on the primary and secondary sides additional compensating capacitors are required (Fig.2) [6]- [8].…”