Wide Output Voltage Range Research Articles

A Wide Output Voltage Range and High Efficiency Dual-Channel WPT System Employing Multimode Control Strategy

A Wide Output Voltage Range and High Efficiency Dual-Channel WPT System Employing Multimode Control Strategy

Design and Implementation of Bridgeless Power Factor Corrector with Low Static Losses

Research and development of power factor corrector (PFC) for AC/DC converters of single-phase AC power supply network are discussed within this article. Two-channel bridgeless PFC is proposed in this paper. The proposed converter allows us to lower current DC component generation in the power network and to reduce static and dynamic losses of semiconductor devices. The suggested solution characteristic features are the absence of a diode bridge while using two identical converters operating in different power network voltage half periods. Due to cumulative chokes in each converter, the function setting the consumption current sinusoidal form is realized with the ability of wide-range output voltage regulation. A number of Simulink-models have been developed in order to study operating modes and to test control algorithms of the proposed bridgeless PFC. The input current harmonic content, efficiency coefficient, passive elements’ electrical parameters, and output voltage pulsation coefficient of the proposed bridgeless PFC were researched by Simulink-models. The results obtained show the efficiency of the proposed solutions regarding PFC. The THD value does not exceed 1.3% in steady state mode and is not over 4% during the voltage stabilization process; the minimal value of the output voltage pulsation coefficient is 3.1%. The suggested solutions can be applied in accumulator batteries’ charging sets and DC motors’ reduced-current start.

Design and optimization of 30 kW CLLLC resonant converter for vehicle‐to‐grid applications

AbstractThe CLLLC resonant converter is a promising technology for electric vehicles and microgrids due to its ability to operate bidirectionally. This article presents a design of a bidirectional CLLLC resonant converter that is applied in the vehicle‐to‐grid (V2G). The battery side of the converter uses a two‐channel parallel structure to enhance its efficiency and reliability. In contrast, the DC‐bus side uses a transformer series structure to obtain the benefits of passive current sharing on the secondary side and reduce the transformer turns ratio. By utilizing the proposed design method, the converter can achieve a wide input and output voltage range, high efficiency, and high power density. The article analyzes the working principle of the converter and explains the design process, which includes the transformer turns ratio, magnetizing inductance, and resonance parameters. Finally, an experimental prototype is produced to verify the theory's validity and the design's feasibility. The prototype has a DC‐bus side voltage of 660–860 V, a battery side voltage of 250–500 V, and a maximum power output of 30 kW. The peak efficiency of the prototype is 98.2%, and its power density can reach up to 8 kW/L.

Design of an integrated EV on-board charger with a wide output voltage range

Design of an integrated EV on-board charger with a wide output voltage range

An Improved LCC-S Compensated Inductive Power Transfer System With Wide Output Voltage Range and Unity Power Factor

An Improved LCC-S Compensated Inductive Power Transfer System With Wide Output Voltage Range and Unity Power Factor

Comparing and Selecting the Optimal Topology of 50kW Fast Charging DC-DC Converter with a Wide Output Voltage Range

Comparing and Selecting the Optimal Topology of 50kW Fast Charging DC-DC Converter with a Wide Output Voltage Range

Optimal Design of LCC Resonant Converter With Phase Shift Control for Wide Input/Output Voltage Ranges in Fuel Cell System

This paper proposes an optimal design of an LCC resonant converter with a phase shift control for a fuel cell system which has wide input and output voltage ranges. The proposed optimal design focuses on the circulating energy minimization by adjusting the transformer turns ratio according to the maximum gain of resonant tank. This makes the root mean square (RMS) value of resonant current and turn-off current stationary even though the resonant tank change. Thus, designers can select resonant tank optimized for the converter specifications without considering the conduction and switching losses. By the proposed optimal design, the efficiency degradation at worst case, which is a significant issue of the fuel cell system with wide output voltage range, can be minimized. In addition, for the fuel cell converter with wide input voltage range, a phase shift control which operates the full-bridge inverter with a constant effective duty cycle according to the fuel cell voltage is proposed. This control scheme improves the light-load efficiency without deteriorating the rated-load efficiency by reducing the circulating current and switching frequency. The validity of the proposed works is confirmed by experimental results of the 30kW LCC resonant converter.

Direct single‐phase isolated improved gamma Z‐source AC–AC converter suitable for DVR application

AbstractA direct single‐phase isolated improved gamma Z‐source AC–AC converter is designed and manufactured in proposed paper. This converter contains an impedance source structure and its advantages. In general, these advantages are as follows. Firstly, the proposed structure has a wide range of output voltage as boost and buck as well as in‐phase or out‐of‐phase states. Secondly, the proposed converter is electrically isolated thanks to a high frequency transformer (HFT), which significantly reduces the volume of the structure; therefore, in applications such as dynamic voltage restorer (DVR), there is no need to install a coupling transformer with the grid frequency which is very bulky and full of losses. Furthermore, the HFT of the proposed converter is a three winding transformer which also acts as the inductance needed for impedance source network. In addition, the safe commutation method has been utilized, which reduces the voltage spikes on the power switches. Finally, the analysis and design of this converter has been done, and then confirmed by a small‐scale laboratory prototype.

Topology, Analysis, and Modulation Strategy of a Fully Controlled Modular Reconfigurable DC Battery Pack With Interconnected Output Ports for Electric Vehicles

Modular battery-integrated converters or so-called dynamically reconfigurable battery packs are expanding into emerging applications. Although they offer many degrees of freedom (DoF), the state of the art focuses on single-output systems and neglects the potential of such systems to generate multiple outputs with minimum added components. This paper investigates the feasibility of a multiport system for various independent loads. The proposed techniques can achieve higher functionality and reduce power conversion stages. Interleaved ports with shared modules can also increase modules’ utilization, avoid redundant power electronics, and reach a better cost-weight trade-off. However, using conventional modulation techniques in particular phase-shifted carrier modulation can be challenging with shared modules among multiple ports, and different control objectives can adversely impact the overall performance. Therefore, this paper analyzes the inherent dynamics of modular batteries and proposes a strategy to decouple the control of multiple ports to simplify power electronics’ complexity and size while improving performance. In addition to the distinct advantages of modular reconfigurable batteries, the proposed concept would not require additional active switches, can operate with a wide range of output voltages, can reduce the size of the filters and transformers, and is extendable to larger setups. Simulation and experiments verify the developed concept.

A Reconfigurable Two-Stage 11 kW DC–DC Resonant Converter for EV Charging With a 150–1000 V Output Voltage Range

In this paper, a reconfigurable two-stage DC/DC resonant topology with a wide output voltage range of 150-1000V is proposed for Electric Vehicle (EV) charging with high efficiency over the entire load range. The proposed topology consists of an LLC resonant converter with dual secondary sides; two interleaved triangular current mode buck converters, and three additional auxiliary switches for reconfiguration. Two possible arrangements of the proposed topology are considered and compared. The analytical model of the topology is developed, which is used for the efficiency estimation of different configurations and the design of the prototype converter. An 11kW hardware demonstrator is built and tested. The maximum measured efficiency of the converter is 97.66%, with a >95% efficiency over the complete 150-1000V range at full power. The proposed two-stage converter achieves the widest output voltage range reported in literature for resonant power converters, thereby capable of charging existing and future EVs very efficiently over any charging cycle.

An MV Hybrid Isolated DC Transformer for Wide Output Voltage Range Applications

DC transformer (DCT) is the key energy conversion equipment that converts medium voltage dc to low voltage dc. Aiming at the industrial loads requiring wide output voltage range and unidirectional power flow, a hybrid isolated DC transformer (HIT) as an alternative to the traditional MMC-DCT is proposed in this paper. It is composed by thyristors, diodes, and submodule (SM) based arms. The operation principle, circuit performance, and control strategy are introduced in detail. Particularly, a discontinuous input and continuous output currents (DICO) operation mode is further proposed to suppress submodule capacitor voltage ripple. Compared with the traditional MMC-DCT, HIT can save 50% SMs, 28% semiconductor cost and 46.3% total SM capacitance. The effectiveness and the theoretical analysis have been confirmed by both simulation and experimental results.

A Wide-Output-Range DC-DC Converter and Minimum Loss Collaborative Control Strategy

In response to the challenges faced by traditional LLC resonant converters in simultaneously achieving a wide output voltage and high efficiency, this paper proposes a cascaded DC-DC converter. The front stage of the converter adopts a new LLC topology, and it is cascaded with a boost converter through a reutilization of the output-side inductor. The proposed DC-DC converter leverages the electrical isolation and wide output voltage range advantages of LLC and boost converters, enabling the overall system to achieve broad output voltage regulation and high-efficiency operation. The reutilization of the inductor design further enhances the integration density of the DC-DC converter. A minimum loss collaborative control strategy is introduced for the proposed DC-DC converter. When determining the output voltage and operating the circuit in step-up mode, the duty cycles of the switch in the proposed LLC converter and the switch in the boost converter are adjusted to minimize overall circuit losses while ensuring the rated output voltage. Ultimately, the correctness and practicality of the proposed DC-DC converter and its control strategy are validated through a simulation and an experiment. The overall efficiency of the DC-DC converter can reach up to 94% under optimal conditions.

SEPIC-Boost-Based Unidirectional PFC Rectifier with Wide Output Voltage Range

A novel unidirectional hybrid PFC rectifier topology based on SEPIC and boost converters is proposed, which is applicable to various industrial applications such as electric vehicle charging stations, variable speed AC drives, and energy storage systems. Compared to other rectifiers, the proposed SEPIC-boost-based rectifier exhibits continuous current on the AC side, lower voltage stress on the active switches, a wider range of DC output voltage, no auxiliary DC-DC converters, and a high step-up static voltage gain operating with low input voltage and a low step-up static gain for the high-input-voltage operation. These traits allow the SEPIC-boost-based rectifier to utilize smaller input-side harmonic filtering inductors and adopt active switches with lower voltage ratings, resulting in reduced conduction losses. Additionally, the proposed rectifier features power factor correction and high boost/buck voltage-gain capabilities, simplifying control for electric vehicle charging and expanding its range of applications. In this paper, the operating principle of the novel topology is presented first, and then the mathematical model of the proposed rectifier is built. Based on this, the comparison between the proposed topology and conventional boost and SEPIC converters is given. Furthermore, the control strategy, including the high-power-factor control and the balancing control to the DC capacitor voltages, is discussed. Finally, to validate the accuracy of the proposed rectifier’s theoretical research, a 500-W SEPIC-boost rectifier system has been constructed in the laboratory, generating a 200/120 Vdc output voltage from a 155 Vpk/50 Hz power source.

High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles

An optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency battery charger for electric vehicles. The convergent approach to TPS mode selection also reduces the numerous cases for small-signal analysis through general average modeling. After verifying the small-signal models under various voltage transfer ratios and load conditions to verify the stability, a converter prototype with a rated power of 15 kW is built and tested. Thus, a peak efficiency of 97.7% can be achieved.

A Current-Fed Dual-Active-Bridge Integrated LC-Resonant Converter with Dynamic Power Allocating for Wide Input and Output Voltage Range Operation

A Current-Fed Dual-Active-Bridge Integrated LC-Resonant Converter with Dynamic Power Allocating for Wide Input and Output Voltage Range Operation

Analysis and Design of a Wide Output Voltage Range Battery Charger for E-Mobility Applications

Analysis and Design of a Wide Output Voltage Range Battery Charger for E-Mobility Applications

A Novel Multimode AC-DC LLC Resonant Converter for Wide Output Voltage Range Applications

A Novel Multimode AC-DC LLC Resonant Converter for Wide Output Voltage Range Applications

A Novel Control Method to Improve Efficiency in Wide Output Voltage Range for Bidirectional Isolated Three-Phase AC/DC Converter Based on Matrix Converter

A Novel Control Method to Improve Efficiency in Wide Output Voltage Range for Bidirectional Isolated Three-Phase AC/DC Converter Based on Matrix Converter

Hybrid LLC Resonant Converter With Partial-Power Auxiliary Unit for Improved Performance

DC-DC converters used in on-board chargers (OBC) of electric vehicles need to meet the requirements of high efficiency, wide output range, and electrical isolation. In this paper, a partial-power processing topology with a wide output range is proposed to overcome the drawbacks of traditional single-stage and two-stage LLC converters. The LLC resonant converter operates near the resonant frequency to maintain high efficiency. While only the partial power is processed by the Buck converter to offer the wide-range output voltage capability. The triangular current mode (TCM) operation is implemented in the Buck converter to minimize the efficiency sacrifice. In addition, to reduce the adverse effect of the second harmonic voltage ripple (SHVR) generated by the AC port on the LLC resonant converter in OBC. A ripple compensation method is proposed to eliminate the SHVR of the LLC resonance converter. Through the dual predictive control for the Buck converter, the SHVR of the LLC resonant converter is offset by the Buck converter. A 2kW rated experimental prototype is designed to convert 400V wide input to 200-500V output. The prototype demonstrates more than 96% efficiency from 30% load to full load at 60-120V input and a 98.2% peak efficiency.

An Energy-Efficient Inverter-Based Voltage Reference Scheme with Wide Output Range Using Correlated Level Shifting Technique

A voltage reference is indispensable in Integrated Circuits. To improve the limited linear output voltage range and energy efficiency of a voltage reference, we innovatively propose a switched-capacitor-based programmable voltage reference scheme employing inverter-based OTAs to reduce the power consumption, simultaneously using a novel Correlated Level Shifting (CLS) technique (without active overhead) to enhance the OTA’s DC gain and integral gain. Experimented with SMIC 180 nm CMOS technology, a scheme-based voltage reference realizes a programable output voltage range from 266 to 995 mV at −30 to 120 °C, and the corresponding temperature coefficient (TC) ranges from 82.4 to 99.5 ppm/°C. The power consumption is 976 nW. Furthermore, comparative experiments and evaluations with other schemes have unequivocally verified the superiority of our proposed scheme, characterized by its high energy efficiency and wide output voltage range. The scheme can be suitably deployed in a multitude of novel edge-data processing systems.