Quasi-resonant Zero Voltage Switching Research Articles

Single-Switch Non-Isolated Resonant DC-DC Converter for Single-Input Dual-Output Applications

This paper describes a new configuration of Cuk and SEPIC (Single-Ended Primary Converter) ZVS-QR (zero-voltage switching quasi-resonant) combination DC-DC converter for bipolar output with a single switch. The proposed topology employs a single ground-referenced power switch, which simplifies the gate drive design with a single L-C resonant network and provides a bipolar output voltage with good regulation, acceptable efficiency and a step-down/up conversion ratio. This configuration provides dual-output voltage by switching the power switch to zero voltage, which is an interesting alternative for many applications where small size, light weight and high power density are very important aspects. In order to verify its performance, a SEPIC–Cuk Combination ZVS-QR prototype with a cost-effective commercial resonant controller was designed and tested. The experimental results show that the proposed combined topology is suitable for Single-Input Dual-Output (SIDO) applications.

Passivity‐based controllers for ZVS quasi‐resonant boost converter

There is a consistent demand for reliable, efficient, small-sized, and light weight power supply for electronics devices. To meet the aforesaid requirements, Quasi Resonant converters are being used due to low switching losses, high efficiency, small size and weight. With these motivations, in this paper, two different methodologies of passivity-based controllers namely (EL-PBC and PCH-PBC) are proposed for Zero Voltage Switching Quasi Resonant (ZVS-QR) boost converter to regulate the output voltage. First, the Euler-Lagrange (EL) formulation is used to derive state-space equations for ZVS-QR boost converter under different operating modes and then, average state-space model is developed using generalized state space average (GSSA) technique. In order to improve the dynamic performance of the ZVS-QR boost converter, the aforesaid passivity-based controllers are designed and its stability analysis is carried out. The entire system is developed with Sim Power System toolbox of MATLAB software and validated through OP-5142 real time simulator. Steady state and dynamic performances are examined under several operating conditions. It is observed that the passivity-based controllers of the paper achieve robustness against the uncertainties at the input and the load side. It is compared with benchmark PI controller as well.

Isolated Bidirectional DC–DC Converter With Quasi-Resonant Zero-Voltage Switching for Battery Charge Equalization

Charge equalization for a series-connected battery string is necessary to enhance usage life and performance of cells. In this paper, an isolated bidirectional dc-dc converter with quasi-resonant zero-voltage switching (ZVS) is proposed for centralized charge equalization system. Through the quasi-resonant operation, the proposed converter can achieve ZVS operations in both boost and buck modes, which decreases switching losses and improves the efficiency. The energy in leakage inductance is released to output side in the boost mode and recycled to the input side in the buck mode, which eliminates the voltage spike. Moreover, the proposed converter has fewer components than existing converters used in the centralized charge equalization system. The operating principle and theoretical derivation of the proposed converter are presented. The ZVS implementations and conditions are analyzed and illustrated in detail. Finally, the experiments using a 7.2 Ah battery string of 13 cells are conducted. The results verify the validity of the proposed converter and show that the equalizer achieves good performance in terms of equalizing speed and efficiency.

A Two-Stage Quasi-Resonant Dual-Buck LED Driver With Digital Control Method

A two-stage quasi-resonant LED driver with a digital control method is proposed in this paper. The first stage of this converter is a boost circuit with a power factor correction function, and the second stage is a dual-buck circuit that works in a quasi-resonant zero voltage switching state. Because of the soft-switching characteristics of the converter, switching losses are reduced and efficiency is significantly improved. A digital control method is adopted to detect the peak value of inductor current and enhance system reliability. Moreover, because LEDs are always driven by a current source, a current loop is designed to maintain constant output current. IRS2104 is chosen as the drive chip and the microcontroller is AT90PWM216, which can improve the quality of the drive signals. The output of the converter is a square wave that drives two branches of antiparallel LEDs. A 60-W prototype was designed to demonstrate the theoretical analysis. The obtained power factor was as high as 0.987 and the efficiency reached 92.3%.

A novel single-stage isolated ac/dc converter with quasi-resonant zero-voltage-switching with a modified forward converter adopting capacitive output filter

A new single-stage isolated ac-dc converter, which can achieve a better efficiency and a better power factor, is proposed. It is based on a general forward topology so that it can utilise the transformer more than converters based on flyback topology. In addition, since the capacitive output filter is adopted instead of an inductive type filter, the voltages on the secondary rectifiers can be clamped to the output voltage; meanwhile, the capacitor used in the output filter can be utilised for the resonance with the leakage inductance, and the turn-off loss in the primary main switch and the dissipative loss in the snubber can be reduced. Moreover, since this converter can be operated at the boundary conduction mode, the line input current can be automatically shaped as the waveform of a line voltage and quasi-resonant zero voltage switching can be also obtained. Therefore, it features higher efficiency, lower voltage stress and a smaller-sized transformer than other topologies. A 100 W prototype has been built and tested for the verification of the proposed topology.

Charge-Equalization Circuit for Series-Connected Batteries with Quasi-Resonant Flyback Converters

A charge equalization circuit for balance discharging in a series-connected battery bank is proposed in this paper. The circuit comprises several parallel-connected flyback converters which connect each unit battery in the bank to supply the electric load. The transformer leakage inductance and capacitances of MOSFETs are applied to fulfill the quasi-resonant zero voltage switching (ZVS), which consequently eliminates the voltage spikes and enhance the conversion efficiency. Design equations are derived and numerical analysis results are applied to evaluate the required values of the inductance and capacitance to realize ZVS performance. A battery bank with four series-connected lead-acid batteries is used to verify the proposed charge equalization circuit. The experimental results advocate the applicability of the proposal.

A ZVS Buck Converter Linked with a Buck-Boost Component.

The development of zero-voltage switching (ZVS) technique has attracted for many industrial applications. In this paper, a quasi resonant ZVS buck converter linked with a buck-boost component is presented. The proposed system has the following features. (1) The large peak current does not flow into the semiconductor switches and the reactors. (2) When a storage battery is used as the power supply, a solar battery can be connected with buck-boost component in order to charge the storage battery. Therefore, this system is very suitable for high power and high efficiency DC to DC converter system.

Use of multielement transformers in quasiresonant convertors

Multielement transformers offer the prospect of low-profile designs with low leakage inductance and good thermal properties. The performances of both high- and low-voltage transformer designs, employing toroidal cores, are evaluated in ZVS-QR (zero-voltage switching-quasiresonant) convertors. It is shown that high transformer power density and good efficiency can be achieved.