Zero-voltage And Zero-current Switching Research Articles

Interleaved full ZVZCS DC–DC boost converter: analysis, design, reliability evaluations and experimental results

In this study, a new interleaved full soft switching DC-DC boost converter with a high power reliability is proposed. To achieve soft switching, a simple auxiliary circuit consisting of one switch, one diode, one inductor and two capacitors is employed in each single-phase DC-DC boost converter connected in parallel. All switches and diodes, including main and auxiliary ones, operate under soft switching conditions. These soft switching conditions consist of zero voltage and zero current switching (ZVZCS) for all switches and diodes at switching transitions except the output diodes, which turn off only with zero current switching. The soft switching technique used in this study decreases power losses which leads the converter to have higher efficiency and reliability. Also, the auxiliary circuit is located out of the main power path preventing high voltage and current stresses on the switches. In this study, operational modes analysis, design procedure, power reliability evaluations and laboratory prototype results with switching frequency of 20 kHz, input voltage of 48 V and output power of 40 W are presented.

Bidirectional Quasi-Cuk DC/DC Converter with Reduced Voltage Stress on Capacitor and Capability of Changing the Output Polarity

In this paper, a bidirectional topology for quasi-Cuk dc/dc converter with capability of zero-voltage and zero-current-switching (ZVZCS) is proposed. The bidirectional quasi-Cuk (BQ-Cuk) converter has different voltage and current transfer ratio, reduced voltage stress on capacitor and capability of changing the output polarity in comparison with conventional bidirectional Cuk converter. In this paper, steady-state analysis of the quasi-Cuk converter with capability of ZVZCS in turn-on is presented. Then, critical inductances for transient from this operation to two new operations are calculated. Next, besides values designing of used elements, maximum and minimum value of their current and voltage are calculated. Finally, experimental results to verify the accuracy of the proposed converter in different operating modes are presented.

A Full Soft-Switching ZVZCS Flyback Converter Using an Active Auxiliary Cell

In this paper, a new soft switching flyback dc-dc converter with a simple zero-voltage and zero-current switching (ZVZCS) cell is proposed. The auxiliary resonant cell consists of one switch, one diode, one inductor, and two capacitors. It provides ZVZCS not only for the main switch but also for the auxiliary switch at both turn-on and turn-off times. In addition, all the auxiliary diodes and body diodes of the switches operate under full ZVZCS except the output diode which turns off only with zero current switching. This soft switching technique makes the proposed converter have less switching losses which leads the converter to operate in higher frequencies and efficiency. Another outstanding feature of the proposed converter is using the auxiliary resonant cell out of the main power path to have lower voltage stress on the switches. In this paper, pulse width modulation (PWM) is employed to control the main switch. A detailed mode analysis of the proposed converter operation is presented along with design procedure. Finally, the accuracy performance of the converter is verified through a 60 W experimental prototype results.

DCM Analysis of Single-Switch-Based ZVZCS Converters With a Tapped Inductor

The analysis of a novel single-active-switch-based zero voltage and zero current switching (ZVZCS) tapped boost converter in the discontinuous conduction mode (DCM) is proposed in this paper. The ZVZCS converter includes a lossless snubber composed of three diodes and two capacitors and exhibits novel ZVZCS operation for wide operating ranges of duty cycles, load currents, and input voltages. The voltage stress of the active switch is always less than the load voltage, and soft switching turn-on and turn-off are achieved without cumbersome current or voltage sensing, which could not have been obtained from quasi-resonant converters that also have an active switch. Detailed analyses of the DCM and the component stresses of the proposed converter are presented. Experiments for a 450-W prototype exhibited 99.0% of the maximum efficiency with a SiC JFET at the switching frequency of 50 kHz, and the ZVZCS operation is guaranteed, even for the DCM under the experimental conditions. Moreover, the proposed ZVZCS principle has been applied to a tapped buck–boost converter case, which was also experimentally verified.

Full-Bridge DC-DC Converter Using Asymmetric Phase-Shifted PWM Control

A novel zero-voltage and zero-current switching (ZVZCS) Full-bridge converter is proposed using Asymmetric Phase-shifted PWM Control, Current in primary winding during the freewheeling period is reduced to zero by adding a blocking capacitor and a saturable inductor, realizing ZCS turn-on and ZVS turn-off for chopping-leg switches as well as ZCS turn-on and turn-off for lagging-leg switches. The control method is easy digital realization, overcomes control precision and flexibility of the traditional phase-shifting control special chip. The operation processes and characteristics of the converter are analyzed, and a prototype is built. Experimental results verify the proposed DC-DC converter with low freewheeling energy, low switching loss and high efficiency.

A Novel Single-SiC-Switch-Based ZVZCS Tapped Boost Converter

A new single-active-switch-based zero voltage and zero current switching (ZVZCS) tapped boost converter is proposed. For the ZVZCS operation of the converter, three diodes and two capacitors were added to an ordinary tapped boost converter. When turned ON, the active switch is in zero current switching with the help of leakage inductance of a tapped inductor. When turned OFF, the energy of the leakage inductance is transferred to a snubber capacitor through a diode, which results in zero voltage switching of the active switch. Then the energy of the snubber capacitor is retrieved by a recovery capacitor connected to the tapped inductor. Different from most conventional soft switching converters that need at least two active switches, the proposed converter requires only one active switch such as JFET and MOSFET to guarantee ZVZCS operation for wide operating ranges of duty cycle, load current, and input voltage. The voltage stress of the active switch is always less than the load voltage, and soft switching turn-on and off is achieved without cumbersome current or voltage sensing, which could not be obtained from quasi-resonant converters that also have an active switch. Furthermore, the dc voltage gain of the proposed converter is quite robust against load change and is determined only by duty cycle like a canonical boost converter; hence, it can be even open-loop controlled. All the diodes are in ZVZCS as well, and all the components except an output diode have the voltage stress less than the load voltage. In this paper, the voltage stress of the output diode was selected to have two times the load voltage. A detailed analysis for the continuous conduction mode and the design procedures of the proposed converter is fully established, and experimentally verified for a 450-W prototype over the input voltage of 100-250 V, achieving 98.1% of maximum efficiency at the switching frequency of 100 kHz with a SiC JFET. Due to its versatile soft switching characteristics, the proposed scheme can be generally applied to high-frequency and high-efficiency dc-dc converters as well as power factor correctors.

Novel Zero-Voltage and Zero-Current Switching (ZVZCS) PWM Three-Level DC/DC Converter Using Output Coupled Inductor

In this paper, a novel zero-voltage and zero-current switching (ZVZCS) pulsewidth modulation (PWM) half-bridge (HB) three-level (TL) dc/dc converter is proposed. Compared with traditional ZVZCS PWM TL dc/dc converters, this converter does not include auxiliary resonant circuits. It can achieve zero-voltage switching (ZVS) for the leading switches and approximate ZCS for the lagging switches with the aid of the transformer parasitic inductance, snubber capacitors, and tapped-inductor-type smoothing filter. This converter can reduce the voltage and current spikes of the power switches as well as the primary circulating current loss effectively. The operation principle of the novel converter and the soft-switching implementation condition are analyzed according to equivalent circuits under different stages. Besides, the effects of the tapped-inductor turns ratio on the current stress of the power switches and the output voltage characteristic under open-loop control scheme are discussed. The validity and features of the proposed converter are demonstrated by simulation results and experimental results via a 6-40 kHz prototype using the fast switching insulated gate bipolar transistor (IGBT).

ZVZCS PWM Converter Using Secondary Active Clamp

A novel zero-voltage and zero-current switching (ZVZCS) pulse-width modulation (PWM) converter is presented in this paper. An active energy recovery clamp in the secondary side provides conditions for zero-current switching (ZCS) of the transistors in the primary side of the DC/DC converter. Zero-voltage switching (ZVS) of the primary switches is achieved by the magnetizing current of the transformer. The active energy recovery clamp provides soft switching of the transistor located on the secondary side of the transformer. The principle of converter operation is explained and analyzed and experimental results obtained on the laboratory model are presented.

Zero-Voltage and Zero-Current Switching Converters

This paper deals with the simulation of a PWM three-level (3L) & five level (5L) converters. The modulation strategies can be classified into two kinds according to the turn-off sequence of the two switches of the pair of switches. The concept of the leading switches and the lagging switches is introduced to realize softswitching for PWM 3L and 5L converters. soft-switching obtained by using both the leading switches and the lagging switches. softswitching PWM 3L and 5L converters can be classified into two kinds: zero-voltage-switching (ZVS) and zero-voltage and zerocurrent-switching (ZVZCS), A three level & five level ZVZCS converters are presented, its operation principle, and the simulation results obtained by using PSPICE are included also.

Zero-Voltage and Zero-Current-Switching PWM Combined Three-Level DC/DC Converter

This paper proposes a zero-voltage and zero-current-switching (ZVZCS) PWM combined three-level (TL) dc/dc converter, which is a combination of a ZVZCS PWM TL converter with a ZVZCS PWM full-bridge converter. The proposed converter has the following advantages: all power switches suffer only half of the input voltage; the voltage across the output filter is very close to the output voltage, which can reduce the output filter inductance significantly; and the voltage stress of the rectifier diodes is reduced too, so that the converter is very suitable for high input voltage and wide input voltage range applications. The converter also can achieve zero-voltage-switching for the leading switches and ZCS for the lagging switches in a wide load range to achieve higher efficiency. The design considerations and procedures are presented in this paper. The operation principle and characteristics of the proposed converter are analyzed and verified on a 400-800-V input and 54-V/20-A output prototype.

A Three-Phase Zero-Voltage and Zero-Current Switching DC–DC Converter for Fuel Cell Applications

In spite of having many advantages, such as low switch voltage and easy implementation, the voltage-fed dc-dc converter has been suffering from problems associated with large transformer leakage inductance due to high transformer turn ratio when it is applied to low-voltage, high-current step-up application such as fuel cells. This paper proposes a new three-phase voltage-fed dc-dc converter, which is suitable for low-voltage, high-current applications. The transformer turn ratio is reduced to half owing to ?-Y connection. The zero-voltage and zero-current switching (ZVZCS) for all switches are achieved over wide load range without affecting effective duty cycle. A clamp circuit not only clamps the surge voltage but also reduces the circulation current flowing in the high-current side, resulting in significantly reduced conduction losses. The duty cycle loss can also be compensated by operation of the clamp switch. Experimental waveforms from a 1.5 kW prototype are provided.

Low Voltage and Current Stress ZVZCS Full Bridge DC–DC Converter Using Center Tapped Rectifier Reset

An improved zero-voltage and zero-current-switching (ZVZCS) full bridge dc-dc converter is proposed based on phase shift control. With an auxiliary center tapped rectifier at the secondary side, an auxiliary voltage source is applied to reset the primary current of the transformer winding. Therefore, zero-voltage switching for the leading leg switches and zero-current switching for the lagging leg switches can be achieved, respectively, without any increase of current and voltage stresses. Since the primary current in the circulating interval for the phase shift full bridge converter is eliminated, the conduction loss in primary switches is reduced. A 1 kW prototype is made to verify the theoretical analysis.

Multi-function zero-voltage and zero-current switching phase shift modulation converter using a cycloconverter with bi-directional switches

A novel voltage source full-bridge DC-DC converter with phase shift modulation using a high-frequency cycloconverter is proposed. Both zero-voltage and zero-current switching (ZVZCS) commutation for full-bridge active power switches and zero-voltage switching operation for cycloconverter bi-directional switches are obtained. Soft switching operation is provided in a wide range of voltage regulation without utilising an auxiliary inductor in the primary side of an isolating transformer. To implement this DC-DC converter as a multi-function DC–AC inverter, a reference signal is traced by the control system to adjust the output voltage according to the variations of the reference signal. Therefore desired output waveforms are provided by selected reference signals. Hence the proposed circuit operates as a multi-function converter. Based on the simulation and experimental results, the steady-state operation principles of the converter are analysed and discussed. Experimental results from a 24 V-DC input and 20 kHz fixed switching frequency laboratory prototype is presented to introduce both the switching operation and the multi-function performance of the converter.

Cost-Effective Zero-Voltage and Zero-Current Switching Current-Fed Energy-Recovery Display Driver for ac Plasma Display Panel

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new cost-effective zero-voltage and zero-current switching (ZVZCS) current-fed energy-recovery display driver for a plasma display panel (PDP) is proposed. It features a simpler structure, less mass, and lower cost of production. Furthermore, since all power switches are turned on or off under zero-voltage or zero-current switching, it has several favorable advantages such as an improved electromagnetic interference (EMI), low switching losses, and reduced burden on the cooling system. Particularly, since the current source built in the inductor can compensate the large gas-discharge current, main inverter switches have the reduced current stress and turnon timing margin. Therefore, the undesirable voltage notch problem caused by the improperly controlled gate signal can be solved, which enables the panel to light at lower voltage such as 143 V compared with about 165 V of the prior circuit. To confirm the operation, validity, and features of the proposed circuit, experimental results from a prototype built with 6-in test PDP are presented. </para>

Zero-Voltage and Zero-Current Switching Full-Bridge DC–DC Converter With Auxiliary Transformer

A novel zero-voltage and zero-current switching (ZVZCS) full-bridge phase-shifted pulsewidth modulation (PWM) converter using insulated gate bipolar transistors (IGBTs) with auxiliary transformer is proposed to improve the properties of the previously presented converters. ZVZCS for all power switches is achieved for full load range from no-load to short circuit by adding active energy recovery snubber and auxiliary circuits. The principle of operation is explained and analyzed and experimental results are presented. The features and design considerations of the converter are verified on a 3-kW, 50-kHz IGBT based experimental circuit.

A family of zero-voltage and zero-current-switching (ZVZCS) three-level DC-DC converters with secondary-assisted regenerative passive snubber

A detailed analysis and optimized-oriented design of a family of three-level soft-switching converters is presented. The zero-voltage-switching (ZVS) of the outer switches and zero-current-switching (ZCS) of the inner switches is realized by employing a pulse-width-modulation (PWM) phase-shift control and a secondary-assisted passive snubber. The switching operation is discussed by comparing the results produced by the use of different passive snubbers (the author's original one and literature-available ones). The voltage on the rectifier diodes is clamped at a reasonable value, specific to each one of the six snubbers taken into consideration. The voltage stress on each transistor is reduced to half of the input voltage. Lower rated transistors and rectifier diodes can be used, thus reducing the conduction losses. Before turning on/off the inner switches, the snubber's capacitor voltage determines the fall of the primary current to zero, thus avoiding wasteful energy circulation and assuring ZCS. The snubber's energy is recuperated to the load. The outcome of these improvements is a high efficiency in energy processing. Soft-switching-oriented constraints on the converter parameters are expressed as implicit equations, whose graphical solution permits the optimized design of the parameters in order to ensure ZVZCS. A comparative analysis of the effective duty cycle and the boost effect of it, due to the use of the secondary snubber, is performed. The influence of the choices of the parameters values on the regulation capability is pointed out. Experimental results prove the expected high performances of the optimized converters.

A Novel Zero-Voltage and Zero-Current-Switching Full-Bridge PWM Converter

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulse-width modulation converter is proposed. The ZCS condition of the lagging-leg is obtained by a simple secondary auxiliary circuit resetting the primary current during the freewheeling stage. The auxiliary circuit's capacitor is charged by the center tape of the secondary through a diode, and the capacitor's voltage is clamped through another diode to output capacitor, thus, the voltage stress on the rectifier is clamped. There are neither additional active switches nor resistances in the auxiliary circuit, which makes the proposed converter efficient.

Zero-voltage and zero-current switching energy-recovery circuit for plasma display panel

A new zero-voltage and zero-current switching (ZVZCS) energy-recovery circuit (ERC) for a plasma display panel (PDP) is proposed. Since its auxiliary circuit is composed of 2 diodes and only 2 power switches compared with 8 diodes and 4 power switches of the prior circuit, it features a simpler structure, less mass, and lower cost of production. Furthermore, since all power switches are turned on or off under zero-voltage and zero-current switching, it has very desirable advantages such as a high efficiency, no serious EMI problem, and low switching losses, and the burden on the cooling system is reduced. In particular, since the current sources built in inductors compensates the plasma discharge current, it could solve the problem of the undesirable voltage drop, which enables the panel to light at lower voltage such as 140 V compared with about 165 V of the prior circuit. Therefore, this proposed circuit is expected to be well suited for the hang-on-the-wall PDP color TV.

A zero-voltage and zero-current switching three-level DC/DC converter

This paper presents a novel zero-voltage and zero-current switching (ZVZCS) three-level DC/DC converter. This converter overcomes the drawbacks presented by the conventional zero-voltage switching (ZVS) three-level converter, such as high circulating energy, severe parasitic ringing on the rectifier diodes, and limited ZVS load range for the inner switches. The converter presented in this paper uses a phase-shift control with a flying capacitor in the primary side to achieve ZVS for the outer switches. Additionally, the converter uses an auxiliary circuit to reset the primary current during the freewheeling stage to achieve zero-current switching (ZCS) for the inner switches. The principle of operation and the DC characteristics of the new converter are analyzed and verified on a 6 kW, 100 kHz experimental prototype.

1차측 환류 다이오드를 제거한 ZVZCS Three Level DC/DC 컨버터에 관한 연구

This paper presents ZVZCS(Zero-Voltage and Zero-Current Switching) Three Level DC/DC Converter without primary freewheeling diodes. The new converter presented in this paper used a phase shirt control with a flying capacitor in the primary side to achieve ZVS for the outer switches. A secondary anxiliary circuit which consists of one small capacitor, two small diodes and one coupled inductor, is added in the secondary to provide ZVZCS conditions to primary switches, ZVS for outer switches and ZCS for inner switches. Many advantages include simple secondary auxiliary circuit topology, high efficiency, and low cost make the new converter attractive for high power applications. Also the circulating current flows through the circuit so that it causes the needless coduction loss to be occurred in the devices and the transformer of the circuit The new converter has no primary auxiliary diodes for freewheeling current. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 1[㎾］ 50[KHz］IGBT based experimental circuit.