Modeling of closed-loop voltage-mode controlled
interleaved dual boost converter
Mummadi Veerachary, Tomonobu Senjyu *, Katsumi Uezato
Department of Electrical and Electronics Engineering, Faculty of Engineering, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami, Okinawa 903-0213, Japan
Received 24 July 2000; accepted 9 January 2001
An extensive small-signal analysis of a voltage-mode controlled interleaved dual boost (IDB) converter operating in continuous current mode based on signal ﬂow graph approach is proposed. Small-signal ﬂow graph is developed, from which open-loop small-signal transfer functions are derived using well known Mason’s gain formula. Closed-loop small-signal input-to-output, control-to-output transfer functions are also derived and frequency response characteristics are determined at diﬀerent duty ratios. Voltage-mode compensator designed using K-factor approach is used for closed-loop operation of IDB converter. Load voltage regulation against supply voltage and load disturbances are demonstrated through experimental results.
Ó 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Interleaved dual boost converter; Small-signal analysis; K-factor; Voltage-mode control
PWM boost dc–dc converters are some of the simplest power electronic circuits. They are widely used in regulated power supplies and also in specialized high power applications such as dc motor drives, battery chargers, plating and welding [1,2]. However, the conventional boost converters have the disadvantages of high ripple content both in the source and load current waveforms, possibility of entering into discontinuous current mode at low switching frequencies, loads etc. To overcome some of these problems, dc–dc converters are frequently paralleled to reduce the ripple content, increase the power processing capability and availability of the power *
Corresponding author. Tel.: +81-98-895-8686; Fax: +81-98-895-8708. E-mail address: email@example.com (T. Senjyu).
0045-7906/02/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 0 4 5 - 7 9 0 6 ( 0 1 ) 0 0 0 1 5 - 5
M. Veerachary et al. / Computers and Electrical Engineering 29 (2003) 67–84
d ðtÞ, d1 ðtÞ average values of the switching functions K1 , K2 D, D1 on time of switch S1 ; S2
DP 1 , DP 2 diodes of individual boost cells
GON , GOFF ON, OFF sub-circuit signal ﬂow graphs
is , i0 input, load current
i1 , i2 individual boost cells inductor currents
ic , iR current through ﬁlter capacitor, load resistance
K1 , K2 switching functions
L1 , L2 inductances of individual boost cells
voltage gain of the converter
R1 , R2 inductor series resistances
Ra , Rb feedback network resistances
S1 , S2 switches of individual boost cells
Vg , V0 input, load voltage
V1 , V2 voltage across inductor branches
electronic system. In the development of new paralleling techniques for dc–dc converters, interleaved power conversion [3,4] constitutes one of the most promising alternatives because of the following advantages: (i) ripple cancellation both in the input and output waveforms to maximum extent (ii) lower value of ripple amplitude, high ripple frequency in the resulting input and output waveforms (iii) eﬃciency of the parallel connected converter system can be improved if a proper number of converters in the system are activated. Further, parallel connection of converters has many desirable properties such as reduced device stresses, fault tolerance for the system, ﬂexibility in the system design etc. This converter system may be subjected to disturbances like source, load and system parameter variations etc. To improve the dynamic performance of the converter system, closed-loop control is essential. In this paper, a simple...