Fifth‐order Π‐type load resonant converters analysis based‐
on immittance property for constant output current
Alireza Khoshsaadat | Javad Shokrollahi Moghani | Mansour Ehsanipour
Department of Electrical Engineering,
Amirkabir University of Technology
(Tehran Polytechnic), Tehran, Iran
Javad Shokrollahi Moghani, Department
of Electrical Engineering, Amirkabir
University of Technology (Tehran
Polytechnic), Tehran, Iran.
Passive resonant tanks (PRTs) with immittance property are suitable candidates
to achieve constant output current in load resonant converters (LRCs). In this
paper, fifth‐order Π‐type LC networks are investigated to accede this target.
At the first step, fifth‐order Π‐type passive LC networks that can be applied
as a PRT are specified based on source and sink natures. Also, their structural
advantages are described in detail to give a suitable perspective for the topology
selection. At the second step, immittance property is verified for the proposed
topologies and immittance PRTs (IPRTs), with their immittance operation con-
ditions, are derived. To confirm the effectiveness, a 150‐W LRC is implemented
leveraging new Π‐type IPRTs. A deep investigation is devoted to analyze the
current/voltage stress in the components of the designed LRC. Moreover,
kVA/kW ratio is considered as a key parameter for the reactive component size
minimization. The proposed constant current LRC presents high load regula-
tion capability in addition to the minimum reactive power and zero‐voltage
switching (ZVS) on the inverter MOSFETs under the various loads. A signifi-
cant robustness against load variations, less sensitivity versus parameters varia-
tion, and relatively higher efficiency are the main superiorities of the fifth‐order
IPRTs to the lower order counterparts.
constant output current, load resonant converter (LRC), passive resonant tank (PRT), reactive
1 | INTRODUCTION
Resonant converters (RCs) are advantageous in many applications such as ballast for the fluorescent lamps,
high‐voltage power supplies,
and power factor correction.
Load resonant converters
is a special group of the RCs, which its conceptual block diagram is presented in Figure 1. It is composed
of 4 major parts named as an inverter, a passive resonant tank (PRT), a rectifier, and a filter.
LRCs can be applied as voltage sources as their constant output against load variations is a significant factor for
power converter designers.
Also, they can be used as a constant current source for many applications such as battery
and LED driving,
by incorporating control methods or inherent properties of the PRTs.
Because the con-
trol methods require extra devices, such as sensors and feedback loop, cost and complexity of the converter can be
Received: 1 August 2017 Revised: 18 January 2018 Accepted: 19 January 2018
Int J Circ Theor Appl. 2018;46:1249–1263. Copyright © 2018 John Wiley & Sons, Ltd.wileyonlinelibrary.com/journal/cta 1249