Multidimensional Ripple Correlation Technique for Optimal Operation of Triple-Active-Bridge Converters

Abstract

The paper presents a multidimensional ripple correlation search technique of optimal operating points of triple active bridge (TAB) converters. Such converters present multiple modulation parameters that should be exploited to achieve high operation efficiency. On the other hand, the several degrees of freedom available make the identification of optimal parameters a challenging task, not easily tackled analytically or in closed form. A modelfree on-line search method based on the ripple correlation technique is then proposed in this paper. The proposed method finds the optimum modulation parameters of TAB converters utilizing a three-dimensional ripple correlation control. The key property of the proposed solution is the adoption of orthogonal perturbation signals, where the orthogonality is simply obtained using different injection frequencies. The multidimensional correlation technique originally shown herein can be applied to other generic optimization problems. The proposed search is verified through a hardware-in-the-loop validation setup and an experimental prototype rated 5 kW.

A Survey on Multi-Active Bridge DC-DC Converters: Power Flow Decoupling Techniques, Applications, and Challenges

“…Taking higher-order odd harmonics into account in a generalized harmonic analysis (GHA) can solve this problem [79,[114][115][116][117]. Some other papers propose black-box model-free approaches to optimally operate the MAB converter without dealing with modelling complexities [99,118].…”

“…Many researchers have focused on other challenges in MAB converters, such as efficiency optimization by implementing advanced modulation techniques [9,11,61,63,65,72,79,85,99,110,[118][119][120][121][122][123][124][125][126][127], and reducing conduction losses using wide bandgap semiconductors such as Silicon-carbide (SiC)-MOSFETs [39,82,128,129], or employing resonant circuits for reducing switching losses [130][131][132][133]. Others have explored fault ride through and analysis [5,32,50,53,81,134,135], electromagnetic interference, and high-frequency oscillation reduction [136] in MAB converters, these aspects are not reviewed or discussed in this paper.…”

“…The work in [67] proposes a normalization design approach for the series-connected inductors in a three-port MAB converter. The work in [19] analyzes the leakage inductance in two-winding and three-winding transformers, and concludes, to have equal and tuned leakage inductances in an MWHFT, cores with symmetrical winding configurations such as toroidal cores are more appropriate, hence, the need for auxiliary series-connected inductors can be eliminated [99,118,127,146].…”

“…Some researchers have proposed model-free approaches for the optimal operation of the MAB converter. The work in [118] proposes a three-dimensional ripple correlation control (RCC) technique for a TAB converter with five degrees of freedom (two outer and three inner phase shifts), and a three-dimensional RCC search for the optimal value of the three inner phase shifts (δ 1 , δ 2 , δ 3 ). Relatively simple implementation, online operation, and robustness of the approach to uncertainties of the circuit parameters are the main advantages of this approach.…”

“…A combination of conventional decoupling and sliding mode control (SMC) is presented in [86]. Other researchers have proposed alternative solutions such as flatness control [98], black-box neural network (NN)-based approaches [21,91,99], and adaptive control [13,85,100], for example.…”