Cost-Effective High-Performance Digital Control Method in Series-Series Compensated Wireless Power Transfer System

Abstract

This paper proposes a control method for a digital signal processor based series-series (SS) compensated wireless power transfer system. In the control method, load resistance and mutual inductance are identified simultaneously, and output voltage can be estimated by using only the primary side voltage and current without direct feedback from the secondary side circuit. Since this estimation method requires a complex mathematical calculation procedure, a digital signal processor is used in this system. One of the major disadvantages of using a digital controller in this system is a limitation of sampling rates. Therefore, in this paper, several current reconstruction methods with limited sampling rates are investigated and applied. As a result, this controller not only reduces the cost of the system but also shows good estimation performance within the limited digital controller unit resource. The proposed control concept is verified by experimental results with a 48W laboratory prototype.

Voltage-Gain Design and Efficiency Optimization of Series/Series-Parallel Inductive Power Transfer System Considering Misalignment Issue

“…Although the voltage-gain of the S/SP IPT system can be load-independent from (11), but there still exists a challenge to the voltage-gain, because G(ω H ) is k-dependent if λ = 1, which is a common case. Figure 7 shows the load-independent voltage-gain G(ω H ) versus the coupling coefficient k under different designs of λ.…”

“…Moreover, as the LCT us usually constrained by its parameters duet to fixed structure and limited space, variable voltage-gains by compensation design should also be taken into consideration to meet specific requirements in some application scenarios [9]. As an example, according to wireless electric vehicle charging standard SAE J2954 TM , a coil and winding geometry specification is suggested, but the bus voltage on vehicle side may differ in level, depending on specifications of the batteries or supercapacitors, which poses challenges in achieving variable voltage-gains without redesigning the LCT [10,11]. Therefore, it is worth optimizing the compensation design for variable voltage-gains against the constraints of LCT parameters.…”