Duality approach to the study of switched‐inductor power converters and its higher‐order variations

Abstract

Switched-inductor technique is a duality counterpart of the conventional switched-capacitor technique. On the other hand, the duality principle is also a useful technique for power converter topology study that is now illustrated by a duality between conventional switched-capacitor and the switched-inductor. The basic switched-inductor converters with current conversions 2, 1/2 and −1 are derived using the duality principle to basic switched-capacitor converters. The operation principle and conversion method have been illustrated in detail. High order of current conversion is also illustrated using the switched-inductor concept. For high step-down version, only two transistors are needed. For high step-up version, the number of transistors is equal to the step-up conversion ratio. Simulation and experimental tests have confirmed the proposed new concept of power conversion. This study presents a useful study guideline to the switching techniques, current sharing and the duality principle for the converters. The converters find applications to power up current-based loads such as light-emitting diode in a digitised manner. The circuits can also be used to provide conversion for current source such as photovoltaic to give multiple or fractional current output. Current mode controlled electrical machine can also be realised easily by the proposed circuit.

Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

“…15(a). Some high-order SL-based converters that can obtain high voltage gain can be found in the literature [86], [88]. A generalized structure with an n-stage VL cell, called the superlift SL, was introduced in [89].…”

Interleaved High Step-Up Converter With Coupled Inductor and Voltage Multiplier for Renewable Energy System

“…In this loop, the different duty cycle Δd is achieved by a simple PI controller through the ΔV between C 3 and C 4 . Then the duty cycle d 1 of the switch S 1 can be easily obtained by (16) By only controlling one of the boost converters, the input current and output voltage of the converter can be easily controlled to be stable. In Fig.…”

“…The red block is the voltage-current dual loop that aims to ensure the stability of the input current and output voltage. From (16), the voltage-balance process is: when the voltage of C 3 is higher than C 4 , the different duty Δd is positive which makes the d 1 decrease. Then the voltage of C 3 comes to decrease to follow V C4 .…”

“…However, the switched-capacitor circuit often requires lots of active switches, and the active switches will also suffer instantaneous large current, increasing conduction loss. In the references [14]- [16], the switched-inductor technology has been combined with basic boost converters for obtaining the high voltage gain, but the voltage value across the power switch is still high, causing serious conduction losses. At the same time, the input current ripples are also large, which affects the lifetime of input dc sources.…”

Programmable Topology Derivation and Analysis of Integrated Three-Port DC-DC Converters with Reduced Switches for Low-Cost Applications

“…With the purpose of providing more new topologies, several topology derivation methods including combination [19][20][21][22], duality [23][24][25] and addition/replacement of cells [26][27][28], have been presented in the past literatures, among which the combination method attracts increasing attentions recently thanks to its systematicness. With the combination method [19][20][21][22], multiple new topologies can be obtained through combining several basic cells in different appropriate ways.…”