Comment on “Storage and Dissipation Limits in Resonant Switched-Capacitor Converters”

Abstract

The purpose of this note is (i) to point to a reference missing in the paper (Mayo-Maldonado et al., 2018) and (ii) to show that some of its content is covered in a more general setting by the results in that reference (Göknar, 1972).

1. Introduction

As explained in the sequel, some of the results developed for specific circuits in Sections 5 and 7 of the paper given in [1] can simply be obtained as applications of results in [2] presented for arbitrary passive circuits containing inductor only cut-sets and/or capacitor only loops.

2. Comments

With Theorem 1 (typo, first Theorem 2 should be Theorem 1) in [2], a measure for the jump in energy is given for a general circuit consisting of inductors (L) and/or capacitors (C) at a time of discontinuity and shown to be positive.

With Theorem 2 for a nonsingular L (C) matrix, it is shown that the necessary and sufficient condition for the jump in energy to be zero is that L currents (C voltages) satisfy Kirchhoff Laws before the jump (at ) [2].

In case of a singular L (C) matrix, Theorem 3 gives a necessary and sufficient condition for the energy at to be zero showing how essential is the nonsingularity of L (C) matrix.

Thus there is no need for all the lengthy derivations for a circuit consisting of two capacitors in Section 5 of paper [1]; they can all be derived simply from the general formulation in [2].

For a circuit N consisting of inductors (capacitors) only, an augmented circuit is obtained from N by including resistors into N in such a way that all L cut-sets (all C loops) are destroyed and when all resistors are open (short) circuited the topology of N is obtained.

Theorem 4 in [2] shows that all L currents (C voltages) in tend to L currents (C voltages) in N as . Furthermore, the fact that the energy jump in N is equal to the energy consumed on the interval in the resistors of is demonstrated in Theorem 5 [2], giving a physical interpretation to the energy jump in N.

It is expected that results in Section 7 of paper [1] can profit from Theorems 4 and 5 of [2].

3. Conclusions

Referring to paper [2] will do justice to it and profiting from its results may shorten the paper [1]. Also, it is quite possible that these results open new horizons for developing further outcomes.

Conflicts of Interest

The author declares that he has no conflicts of interest.