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A PWM Plus Phase-Shift Controlled Interleaved
Isolated Boost Converter Based on Semi-Active
Quadrupler Rectifier for High Step-Up Applications
Abstract:
Semi-active quadrupler rectifiers (SAQRs) are proposed in this paper to serve as
the secondary rectification circuits, which make the secondary-side voltages be
controllable and help to reduce current stress and conduction losses. An interleaved
isolated boost converter is developed based on the proposed SAQRs. By utilizing
the pulse-width-modulation (PWM) plus phase-shift control strategy, the primary
and secondary-side voltages are well matched to reduce the current values and
circulating conduction losses. With the proposed SAQRs, the voltage gain is
extended and the voltage stresses on power devices and passive components used
in rectification circuits are reduced to the half of the high output voltage. Hence,
the efficiency is improved by using a transformer with a smaller turns ratio and
reduced parasitic parameters, and by employing low voltage rating devices with
better switching and conduction performance. With optimal design, lower voltage
and current stresses on the primary-side switches, minimized input current ripple
can be realized. Moreover, the zero-voltage turn on switching of the active
switches and the zero-current turn off switching of the diodes can be achieved over
a wide load and voltage range by the proposed SAQR based converter and the
control strategy. Meanwhile, the higher voltage gain, and the lower voltage and
current stresses on power devices can be obtained with the proposed SAQR based
converter compared with passive quadrupler rectifier based converter. The
feasibility and effectiveness of the proposed SAQRs and the derived converter are
verified by a 380V output prototype.
Existing system:
 POWER systems sourced by renewable energy sources and batteries have
been becoming the effective solutions to compensate the global energy
shortage and environmental problems.
 Commonly the two stage configuration constructed by a front-end DC-DC
converter and a grid-connected inverter is widely used, due to the low output
voltages of these renewable energy sources and batteries.
 Hence, the high step-up voltage conversion ratio is required for the DC-DC
stage to convert the low voltages into a sufficiently high voltage for the
inverter.
Proposed system:
 In the proposed system, the concept of semi-active quadrupler rectifiers
(SAQRs) are proposed to alleviate the limitations of the current-fed
converter.
 These SAQRs are derived by replacing the diodes in rectification circuits by
active switches or by adding the extra bidirectional switch.
 The major contribution is to propose the novel interleaved isolated boost
converter by employing the SAQRs. Lower voltage stresses on the primaryside switches and lower current stresses on the secondary-side rectification
circuit have been achieved for the proposed SAQR based converter
compared with those with passive rectifiers.
Circuit diagram:
Reference:
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