Energy and Power Engineering, 2013, 5, 657-660

doi:10.4236/epe.2013.54B127 Published Online July 2013 (http://www.scirp.org/journal/epe)

Research on Con t rol Strategy of 2 - p h a s e

Interleaving Magnetic Integrated VRM

Rui Guo1,2, Con g Wang 1,Yugang Yang2

1School of Mechanical Electronic & Information Engineering, China University of Mining & Technology, Beijing, China

2Faculty of Electrical and Control Engineering, Liaoning Technical University, Huludao, Liaoning, China

Email: 13591991002@163.com

Received February, 2013

ABSTRACT

A kind of 2-phase interleaving coupled magnetic integrated VRM is studied and the corresponding passivity-based con-

trol strategy is put forward. The model of this kind of magnetic integrated VRM is constructed, and the performance of

this 2-phase interleaving magnetic integrated VRM of passivity-based control is verified by simulation experiments.

The results proved that this kind of passivity-based control strategy can decrease the steady state current ripple and the

dynamic output voltage under load disturbance.

Keywords: VRM; Magnetic Integrated; Interleaving; Coupled Inductors

1. Introduction

Nowadays, the topology used in VRM is mostly multi-

phase interleaving Buck converter, in which the magnetic

components have important effect on the performance of

VRM. In order to increase the power density and effi-

ciency of VRM, the magnetic integration technology is

applied to it [1-3]. However, each phase winding of the

multi-phase magnetic integrated VRM has a self induc-

tance, meanwhile, it can form coupled magnetic circuit

with the other phase windings. Therefore, it is difficult to

construct the model of VRM and the traditional linear

control methods can not meet the demand of the per-

formance [4]. A kind of 2-phase negative coupling mag-

netic integrated VRM is studied in this paper and its cir-

cuit model is constructed using linear system control

theory, what’s more, the corresponding nonlinear passiv-

ity-based control strategy is put forward to realize the

equality of each phase current and to improve the dy-

namic performance of VRM.

2. Model Building of 2-phase Interleaving

Magnetic Integrated VRM

The model of 2-phase interleaving negative coupled

magnetic integrated VRM is shown in Figure 1. There

are 4 operation modes in each switch cycle, and the cor-

responding equivalent circuits are shown in Figure 2.

Supposed that VRM operates in the mode of continu-

ous current, and the 4 operating modes of VRM are de-

fined as “Σ1”, “Σ2”, “Σ3” and “Σ4”. The state variables are

selected as

123

T

x

xx, where “x1” and “x3” are cur-

rents “i1” and “i2”, “x3” is voltage “uc” , “Lk” is leakage

inductance, “k” is coupling coefficient, and “R” is the

load resistance. The models of the 4 modes “Σ1”, “Σ2”,

“Σ3” and “Σ4” are as follow:

11

22

3

1

00

1

1

:00 0

(12 )0

11 1

1

00

0

1

:00 0

0

11 1

1

00

1

:00

11 1

K

in

oo

KK

K

oo

K

K

in

KK

Lk

V

1

2

xA

LLk

RC RC RC

L

xxAxb

L

RC RCRC

L

V

xx

LL

RC RCRC

xb

33

0

1

(12 )0

oo

kAxb

k

*Sponsor: National Natural Science Foundation of China (No.

51177067 and No. 51077125)

Copyright © 2013 SciRes. EPE