Quasi-resonant DC-DC Converter Research Articles

Comparison of Different Optimization Techniques for Model-Based Design of a Buck Zero Voltage Switching Quasi-Resonant Direct Current to Direct Current Converter

The present paper provides a comparison of different optimization techniques applied to the model-based design of a Buck Zero Voltage Switching (ZVS) Quasi-Resonant DC-DC Converter. The comparison was made both on the basis of the duration of the optimization procedures and in terms of guaranteeing the performance of the power electronic device. The main task of the paper is to present various techniques based on the use of mathematical software for the optimal design of Quasi-Resonant DC-DC converters. These topologies were chosen because in them, the design is carried out according to computational procedures, in which several iterations are often necessary for the successful completion of the process. An optimization procedure with a target function reference curve of the output voltage was used. In this way, the optimization is performed without the need for a complete design of the device but only by using base ratios, design constraints, and past experience to determine initial values and intervals of change in circuit parameters. This is also the main advantage of the used optimization of the reference curve type of the output, compared to applying other objective functions, such as achieving minimum losses or maximum efficiency of the device.

A Novel High-Voltage-Gain Quasi-Resonant DC–DC Converter With Active-Clamp and Switched-Capacitor Techniques

We propose an isolated high-voltage-gain quasi-resonant dc-dc converter with a bi-functional circuit for the renewable energy applications. The proposed converter adopts an interleaved connection in the primary side, reducing input current ripple, and includes the bi-functional circuit operating as the switched-capacitor cells and two active-clamped circuits simultaneously. The converter realizes high voltage conversion ratio without using extreme duty ratio, and the voltage spike due to the leakage inductance of the isolation transformer is clamped. In addition, an output voltage doubler in the secondary side comprises a series resonant circuit and then obtains zero current switching (ZCS) turn-off of rectifying diodes; the diode reverse recovery problems are also alleviated. A 320W laboratory prototype that operates at input of 26 V-34 V and output of 400 V is fabricated to verify the effectiveness of the proposed converter.

DC-DC High-Step-Up Quasi-Resonant Converter to Drive Acoustic Transmitters

This paper proposes a quasi-resonant step-up DC-DC converter to provide the DC-link voltage for piezoelectric transmitters (PZETs). The resonance not only provides a soft-switching condition for the converter switches, but also helps to decrease the converter element sizes for marine applications. Operation modes of the proposed converter are discussed. The current and voltage of the converter components are derived analytically, and hence the converter gain is obtained. The performance of the proposed high-step-up, high-power density converter is examined through a comprehensive simulation study. The simulation results demonstrate the soft-switching operation and short transient time required for the converter to reach the reference output voltage. The converter output voltage remains unchanged when an inverter with a passive filter is placed at its output while supplying the PZET. The proposed DC-DC converter is prototyped to validate the converter gain and soft-switching operation experimentally. The converter gain and soft-switching results in simulation are well matched with those of the experimental tests. The converter efficiency in three different switching frequencies is obtained experimentally. The power density of the proposed topology is determined via the designing of a printed circuit board. The experimental results demonstrate the appropriate gain and efficiency of the converter in the tested power range.

A Two-Stage Isolated High Step-Up Quasi-Resonant DC-DC Converter with Pre-Voltage Regulator

A two-stage isolated high step-up quasi-resonant DC-DC converter with pre-voltage regulator is proposed in this article. A quasi-resonant network and a voltage doubler are added on the secondary side of the transformer to achieve voltage lift-up in the latter stage, which can realize the ZVS turn-on of primary switches and there is also no reverse recovery loss in the secondary side diodes. In order to ensure the efficient operation of the system, the latter stage is designed to operate at the rated state to achieve a constant output. While the front-stage synchronous Buck-Boost converter acts as a voltage regulator to realize constant voltage regulation in a wide input voltage range. An experimental prototype with an input voltage range of 20-28 V and output 400 V/ 0.5 A is built under 1 MHz switching frequency. A peak efficiency of 93.6% is achieved. The experimental results verify the correctness of the theoretical analysis.

A Quasi-Resonant Current-Fed Converter With Minimum Switching Losses

A quasi-resonant dc-dc converter with high voltage gain and low current stresses on switches is proposed in this paper. This converter preserved inherent advantages of current-fed structures, for instance, zero magnetizing dc offset, low input ripple, and low transformer turn ratio. Moreover, by employing the active-clamp circuit, the voltage spikes across the main switch, due to the existence of leakage inductance of the isolating transformer, is absorbed, and switches work in zero voltage switching. Since quasi-resonant switching strategy is employed, turn-off current (TOC) and losses of switches are considerably reduced. Because of zero current switching (ZCS), reverse recovery problem of diodes is alleviated. Experimental results on a 150-W prototype are provided to validate the proposed concept.

Analysis and design of an interleaved current-fed high step-up quasi-resonant DC-DC converter for fuel cell applications

This paper proposes a current-fed quasi-resonant converter with soft switching method. Input current ripple is reduced by employing two boost circuits at the input, which makes this converter appropriate for fuel cell application. Current stress on switches is reduced because of the resonance in switches, and also, as a result of zero voltage switching in switches, switching losses will be reduced in this proposed converter. In the output, the reverse recovery problem of diodes is alleviated by zero current switching, so there is no need for fast diodes anymore. The reduction of losses improves the efficiency, and in a wide range of load, efficiency is high. Experimental results on a 1-kW prototype are provided to validate the proposed concept.

Operation analysis of quasi-resonant high-frequency transformer link DC-AC converter applied for phase-shift PWM control in secondary side

In recent years, the soft-switching techniques have attracted attention for its peculiar advantages such as low swtching loss, high-power density, EMI/RFI noise reduction and so on. Authors have already reported before about quasiresonant DC-DC converter using new phase-shift PWM control scheme. By using proposed control scheme, circulating current is elimineted and ZVS (Zero Voltage Switchig) is achieved with small commutating current. As a result, the conduction losses caused by their currents are substantially reduced.In this paper, authors apply a proposed control scheme to a quasi-resonant high-frequency transformer link DC-AC converter. As a result, all switching devices in this DC-AC converter can achieve soft-switching with small commutating current irrespectively of inverter mode and rectifier mode. Its operating principle and unique features are described as compared with the symmetrical control scheme of DC-ACconverter. Operating performance of this DC-AC converter in steady-state are illutrated by means of simulating results.

Comparison of the square-wave and quasi-resonant topologies

The waveforms of a square-wave DC-DC converter and a quasiresonant DC-DC converter are examined in detail and a comparison is made between the switching losses and conduction losses for each topology. Using data from commercially available semiconductor devices, conservative estimates are then given for the switching frequency at which the resonant approach becomes advantageous. The effect of an isolation transformer on this comparison is also addressed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>