Zero Voltage Switching Operation Range Research Articles

Comprehensive Analysis of ZVS Operation Range and Deadband Conditions of a Dual H-Bridge Bidirectional DC-DC Converter with Phase Shift Control

This study offers a thorough examination of the zero voltage switching (ZVS) operation range and deadband conditions for a bidirectional DC-DC converter with phase shift control, featuring dual H-bridge. The analysis considers the soft switching range of the DAB converter, accounting for the impact of the headband and the ZVS capacitor. By applying the differential equation of the circuit during deadband time, a sufficient constraint for the input and output bridges can be calculated. The findings indicate that as the output voltage increases, the minimum phase shift value required to achieve ZVS decreases, and expanding the phase shift value will expand the ZVS range and reduce switching losses. The study provides simulation results for various operating conditions, validating the theoretical analysis of the proposed system. In addition, the results furnish information about the circuit behavior during the deadband and waveforms. Finally, MATLAB/SIMULINK verifies the simulation results for different operating stages.

Analysis and Design of a High-Frequency Isolated Dual-Transformer DC-DC Resonant Converter

This paper presents the operation, analysis, design, simulation, and experimental results for a proposed Dual-Transformer DC-DC Resonant Converter (DTRC). A three-arm bridge is employed on the input side and an H-type bridge is employed on the output side of the DTRC, and the two bridges are connected with two high-frequency (HF) transformers. By optimizing the ratio k of the two HF transformers, the proposed DTRC has a lower boundary power for losing zero-voltage switching (ZVS). That means the DTRC has a wider ZVS operation range and lower switching loss when compared with a traditional soft-switching pulse width modulation (PWM) resonant converter. The operation principle, power transfer, ZVS characteristics, and design procedures are analyzed in detail. Both simulation and experimental results prove the feasibility and superiority of the proposed Dual-Transformer DC-DC Resonant Converter.

Extension of ZVS Region of Series–Series WPT Systems by an Auxiliary Variable Inductor for Improving Efficiency

To maintain a stable output voltage under various operating conditions without introducing extra dc/dc converters, phase-shift (PS) control is usually adopted for wireless power transfer (WPT) systems. By using this method, however, zero-voltage switching (ZVS) operation cannot be guaranteed, especially in light-load conditions. To achieve high efficiency and reduce electromagnetic interference, it is significant for WPT systems to achieve ZVS operation of all switching devices in the whole operation range. In this article, an auxiliary variable inductor, of which the equivalent inductance can be controlled by adjusting the dc current in its auxiliary winding, is designed for series–series-compensated WPT systems under PS control to mitigate the loss arising from hard switching. As a result, a wide ZVS operation range of all switching devices can be achieved. A laboratory prototype is built to verify the theoretical analysis. The experimental results show that, under load and magnetic coupling variations, ZVS operation at fixed operation frequency as well as a constant dc output voltage can be maintained. Compared to the conventional method with only PS control, the proposed WPT can achieve higher overall efficiency in a wider load range owing to the wide ZVS operation range.

A Control Strategy for Efficiency Optimization and Wide ZVS Operation Range in Bidirectional Inductive Power Transfer System

The efficiency of bidirectional inductive power transfer (BIPT) systems is strongly dependent on the load. Besides, the soft-switching operation of power switches is critical to high-frequency converter in the BIPT systems. In this paper, a triple-phase-shift (TPS) control strategy is proposed to achieve load matching while realizing zero voltage switching (ZVS) for all power switches within the entire power range. The load matching condition of the BIPT system with double-sided LCC compensation network is analyzed. And a dual side phase shift control is proposed to adjust power flow while realizing load matching. To realize ZVS operation, the third phase shift between primary and secondary side is introduced as an extra control variable. A time domain model of double-sided LCC compensation network is established to analyze the ZVS range. With the proposed TPS control, wide ZVS operation range of the system can be achieved while maintaining load matching. At last, a scale down prototype of 1 kW BIPT system is developed. The experimental results show good agreement with theoretical analysis, all switches realize ZVS within the entire power range and a peak efficiency of 94.83% is achieved.

A Novel Soft-Switching Secondary-Side Modulated Multioutput DC–DC Converter With Extended ZVS Range

In this paper, a novel soft-switching secondary-side modulated dc–dc structure with extended zero voltage switching (ZVS) range is proposed. In a simple manner, this structure can be extended to provide isolated multioutputs with independent voltage regulation capability. Besides, the secondary side can be bidirectional to interface with energy storage elements such as batteries and ultracapacitors. The proposed topology is suitable for high voltage gain or high output dc-link voltage, low-power, and multioutput applications. The primary-side full-bridge switches operate complementarily to generate a two-level square wave. Therefore, the circulating energy is significantly smaller than conventional phase-modulated full-bridge converters. The output voltage is regulated by controlling the duty cycle of the auxiliary mosfet on the active/semiactive rectifier, which offers a simple control. Moreover, the ZVS operation range of full-bridge mosfet s is enhanced due to the volt-second balance of magnetizing inductance and the secondary-side control. All the secondary-side rectifying diodes turn off with limited di / dt. A 1-kW prototype generating two 390 V, 330–400 V outputs from a 130–180 V dc link is designed to serve as a proof of concept. The full-load efficiency is 95.6% at 100 kHz switching frequency.

Different Purpose Design Strategies and Techniques to Improve the Performance of a Dual Active Bridge With Phase-Shift Control

This paper addresses the performance of the bidirectional dual active bridge (DAB) converter. One of the advantages of the DAB is the possibility to achieve the zero-voltage switching (ZVS) operation in all the switches of this converter. However, the ZVS operation range can be lost for light loads, especially if high voltage is required in at least one of the DAB ports and the phase-shift control is used to regulate the power processed by the converter. Theoretically simple averaged and small-signal models are presented for the DAB converter. Using the study presented in this paper, the boundaries of the ZVS operation can be easily evaluated. The proposed models and analysis of the ZVS boundaries allow the proposal and evaluation of two different design strategies with different purposes: on the one hand, increasing the ZVS operation range and, on the other, improving efficiency at full load. Moreover, some techniques are presented for increasing the ZVS operation range and improving the efficiency of the DAB at full load (both using phase-shift control) employing the aforementioned analysis to obtain certain design criteria and conclusions. Finally, the proposed models, design strategies, and techniques to improve the performance of the DAB are experimentally tested using a 1-kW prototype with input and output voltages of 48 and 400 V, respectively.

Coupled Inductor Incorporated Boost Half-Bridge Converter With Wide ZVS Operation Range

A new boost half-bridge (BHB) converter is presented. It is composed of an additional diode and a coupled winding to the boost inductor of the BHB converter. Using the transferring of a boost inductor current to the coupled winding, the cancellation of zero-voltage-switching (ZVS) current, which always occurs in a conventional one, is prevented. Therefore, the ZVS operation is easily achieved by the leakage inductor current of the transformer. Furthermore, since the negatively built-up leakage inductor current of the boost winding helps the ZVS operation throughout a wide load range, the ZVS operation is always guaranteed.

Nonisolation Soft-Switching Buck Converter With Tapped-Inductor for Wide-Input Extreme Step-Down Applications

In this paper, a new zero-voltage switching (ZVS) buck converter with a tapped inductor (TI) is proposed. This converter improves the conventional tapped inductor critical conduction mode buck converters that have the ZVS operation range determined by the TI turn ratios. It includes another soft switching range extension method, the current injection method, which gives an additional design freedom for the selection of the turn-ratios and enables the optimal design of the winding ratio of the TI so that the efficiency may be maximized. This soft-switching buck converter is suitable for wide input range step-down applications. The principle of the proposed scheme, analysis of the operation, and design guidelines are included. Experimental results of the 100-W prototype dc-dc converter are given for hardware verification also. Finally, based on the proposed soft-switching technique, a new soft-switching topology family is derived.