Wide Input Voltage Range Research Articles

A switched quasi Z-source three-port (SqZSTP) DC-DC converter for a photovoltaic power generation system

In this paper, a modified wide-input switched quasi Z-source three-port (SqZSTP) DC-DC converter is proposed to interface a photovoltaic inverter with a distributed power generation system. The proposed SqZSTP DC-DC converter constructed with a quasi Z-source impedance network and a three-winding high-frequency transformer offers high voltage gain over a wide input voltage range. In the proposed topology, the input port is divided into two ports, to reduce the power rating and voltage stress across each component. The design and operating principles of the SqZSTP DC-DC converter are presented. The steady state and dynamic performance of the proposed SqZSTP DC-DC converter are compared to other converters that have an impedance network in front. The fuzzy logic controller used in the voltage loop avoids variation in the output voltage when a wide variation in the input voltage happens. In order to test the proposed topology, a scaled-down model with a voltage and power rating of 400 V/1400 W was developed. AT conversion efficiency of 94.5% is achieved.

Improvement Method for Light Load Efficiency of DAB Converter with Wide Input Voltage Range

This study proposes a control method for a dual active bridge (DAB) converter for battery systems to improve loss of light load. The proposed method reduces the circuit gain nonlinearity caused by phase shift control focused on the transformer losses. Therefore, based on calculations through the model of the proposed method and experimental results from load switching, the proposed method is shown to have lower light load loss and better controllability than conventional methods.

A 10 mV-500 mV Input Range, 91.4% Peak Efficiency Adaptive Multi-Mode Boost Converter for Thermoelectric Energy Harvesting

This paper presents a multi-mode boost converter to achieve the high efficiency over a wide input voltage range for thermoelectric energy harvesting (TEH) applications. Under high, medium, and low input voltages, continuous conduction mode (CCM), critical conduction mode (CRM), and discontinuous conduction mode (DCM) are adopted to improve the conversion efficiency, respectively. Moreover, a constant peak current (CPC) control scheme is proposed to realize high efficiency under ultra-low input voltage. The proposed converter is implemented in a 0.18 μm standard CMOS process, which occupies a chip core area of about 1.0 mm x 0.9 mm. It achieves >60% efficiency in the range of TEG open-circuit voltage $V_{S}$ from 20 mV to 500 mV, and a peak efficiency of 91.4%. Moreover, after the startup is completed, an efficiency of 37.1% under the $V_{S}$ as low as 10 mV can be achieved.

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.

0.5 V Differential Difference Transconductance Amplifier and Its Application in Voltage-Mode Universal Filter

This paper presents an innovative CMOS structure for Differential Difference Transconductance Amplifiers (DDTA). While the circuit operates under extremely low voltage supply 0.5 V, the circuit’s performance is improved thanks to using the multiple-input MOS transistor (MI-MOST), the bulk-driven, self-cascode and partial positive feedback (PPF) techniques. As a result, the DDTA structure is less complex, with high gain of 93 dB, wide input voltage range nearly rail-to-rail, and wide transconductance tunability. As an example of application, a second-order voltage-mode universal filter using three DDTAs and two 6 pF integrated capacitors is presented. The filter is designed such that no matching conditions are required for the input and passive components, and the input signals need not be inverted. The natural frequency and the quality factor can be set orthogonally while the natural frequency can be electronically controlled. The circuit was designed and simulated in Cadence environment using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18 \mu \text{m}$ </tex-math></inline-formula> TSMC technology. The simulation results including intensive Monte-Carlo (MC) and process, temperature, voltage (PVT) analysis confirm the stability and the robustness of the design to process, mismatch variation and PVT corners.

Multiple output high gain DC-DC converter

Multiple output DC-DC converters with high gain are the most cost-effective development in improving renewable energy applications. The high gain DC-DC boost converters can convert low voltage from renewable energy sources to high DC bus voltage level. The multiple output high gain converter has advantage of multilevel outputs which eliminate the requirement of individual converters for each voltage level. The DC-DC boost converter with multiple outputs provides boost outputs with different gains at low duty ratios with higher efficiency. The non-isolated multiple output DC-DC converter works on switched-capacitor and switched-inductor technique with a wide input voltage range. The dual power switches are driven with a single PWM drive signal. The voltage stress across components is less than half of the main output voltage. The dual outputs with single input reduce size and cost of the high gain converters in modern power electronics. The operation of DC-DC converter analysed in continuous conduction mode. The performance study of the multiple output high gain DC-DC converter is carried out with MATLAB/SIMULINK R2017b for 100W/20kHz.

Wide-Range Light Harvesting Module for Autonomous Sensor Nodes

A large number of autonomous devices is nowadays supported by renewable and green energy sources. A vital sub-circuit in such systems is the power converter circuit, which should efficiently transform and store the available energy. In order to obtain the maximum efficiency under varying energy conditions, various maximum power point tracking (MPPT) methods are used. In this work a complete harvesting module with battery management and MPPT is presented, suitable for a plethora of autonomous applications. A novel, low-complexity and ultra-low power consumption design is proposed, which offers very wide operating voltage and power range with high MPPT efficiency and very low power consumption. It can be combined with different harvesters, such as thermoelectric generators or photovoltaic panels and is able to work under widely varying energy conditions. As supported by experimental results, the proposed module covers a very wide working input power range, from 40 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> up to 4 W, as well as a very wide input voltage range, from 650 mV up to 2.8 V with 96.5% average MPPT efficiency and a total power consumption of 3.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> at 3.6 V. The module relies on an embedded ultra-low power microcontroller unit (MCU) to perform the power management and MPPT operations, which can also be used for extra tasks (e.g., sensor reading). Using the proposed module, an autonomous sensor node was built, able to acquire acceleration measurements, and wirelessly communicate with a remote user in order to send an alert or stream the acquired sensor data in real time.

Switched inductor based transformerless boost inverter

Photovoltaic (PV) power systems have become one of the most common renewable energy sources during last ten years. Normally, the inverter acts as the primary link between the solar cells and the AC load. Generally, the output voltage of the PV system is low so to increase the output voltage, a switched inductor concept is introduced. Thus, here a switched inductor based transformerless boost inverter for standalone photovoltaic generation systems is designed. This boost inverter is the combination of boost converter with the typical full bridge inverter. The inverter consists of five switches in which only two switches are operated at high frequency state and rest others are operated at lower frequency state. Also rectified sinusoidal pulse width modulation (SPWM) based control strategy is used, to realize the voltage pumping and the control of output voltage. So that, the modulation strategy of switches is very simple, which reduces the switching losses. Thus, the inverter has high voltage gain and high efficiency. The performance study and analysis of switched inductor based transformerless boost inverter is carried out with MATLAB / SIMULINK R2017b. This boost inverter can work in a wide input voltage range.

Battery Energy Storage System With Interleaving Structure of Dual-Active-Bridge Converter and Non-Isolated DC-to-DC Converter With Wide Input and Output Voltage

We propose a circuit topology suitable as a battery charge/discharge tester with a DAB converter and a non-isolated dc-dc converter as a module structure. The module structure can be configured to have a wide input and output voltage range because it is easy to expand. DAB converters are used for bidirectional power transfer and galvanic isolation. By controlling the phase difference of the voltages across the DAB to be almost identical, the generation of circulating current due to the phase difference is minimized, and the ZVS is guaranteed. In addition, by switching at a phase angle that flattens the DAB switch current, the peak current is reduced to diminish the switch’s conduction loss, lowering the switch current rating, and reducing the magnetic core size. The non-isolated dc-dc converter is used to control the battery output voltage. Through the interleaved structure, good dynamic characteristics and current ripple can be reduced, so the effect of improving the battery lifecycle can be expected. We present four series-parallel structures of the proposed converter and compare them with the case of generating an output voltage only with a DAB converter. Analyze the characteristics of automatic voltage balancing due to the difference between the input capacitors’ initial voltage and capacitance connected in series. We analyze the features of the proposed system through simulation and verify the technical feasibility and excellence of the proposed battery charge/discharge tester through charge/discharge experiments using supercapacitors instead of batteries.

Wide Input Variable Mode ZVZCS Converter Design

With the emphasis on energy conservation and emission reduction in various countries, industries such as new energy power generation and electric vehicles have developed rapidly. In many applications, the converter needs to adapt to a wide input voltage range, for example, the input voltage range of electric car charger is 200 &#x007E; 450V. Based on this, this paper proposes a wide-input variable-mode ZVZCS converter for electric vehicles with two operating modes. Before the MOSFETs of the lagging-legs is opened, the primary side current is extinguished by the auxiliary circuit to realize ZCS. Due to the parasitic inductance and diode of MOSFETs, ZVS is realized by MOSFETs on leading-legs. It not only broadens the input voltage range of the traditional phase-shifted full-bridge ZVZCS converter, but also keeps the advantages of the traditional phase-shifted full-bridge ZVZCS converter, such as wide load range and small duty cycle loss. Experimental results with 60 &#x007E; 240 V input voltage are demonstrated to verify the advantages.

A Unified Controller for Multi-State Operation of the Bi-Directional Buck–Boost DC-DC Converter

DC grid interfaces for supercapacitors (SCs) are expected to operate with a wide range of input voltages with fast dynamics. The class-C DC-DC converter is commonly used in this application because of its simplicity. However, it does not work if the output voltage (V2) becomes smaller than the input voltage (V1). The non-isolated bi-directional Buck–Boost DC-DC converter does not have this limitation. Its two half-bridges provide a means for controlling the power flow operating in the conventional dual-state mode, as well as multi-state, tri, and quad modes. These can be used for mitigating issues such as the Right Half Plane (RHP) zero that has a negative impact on the dynamic response of the system. Multi-state operation typically requires multi-variable control, which is not easy to realize with conventional PI-type controllers. This paper proposes a unified controller for multi-state operation. It employs a carrier-based modulation scheme with three modulation signals that allows the converter to operate in all four possible states and eight different modes of operation. A mathematical model is developed for devising a multi-variable control scheme using feedback linearization. This allows the design of control loops with simple PI controllers that can be used for all multi-state modes under a wide range of operating conditions with the same performance. The proposed scheme is verified by means of simulations.

Single-switch boost-buck DC-DC converter for industrial fuel cell and photovoltaics applications

The realization of dc-dc converters performs a vital function in exploiting renewable energy sources such as solar photovoltaic (PV) and fuel cell applications. This paper demonstrates a single-switch unidirectional buck-boost dc-dc converter for continuous power flow control, excluding the hybrid switched-capacitor. The proposed converter utilizes a limited number of passive components, only four diodes and three inductors required, in addition to six capacitors. The converter can operate at a wide input voltage range with continues input current. The converter has experimented under real-time conditions with 660 W PV system. The obtained efficiency ranges from 93% to 98%. Furthermore, the converter has interfaced with 550 W fuel cell operated under different fuel pressure. The realized efficiency ranges from 91% to 97%. The maximum measured inductance current ripple is limited to under 0.70 A in both scenarios, whereas 0.16 V is the maximum output voltage ripple.

A Compensated Peak Current Mode Control PWM for Primary-Side Controlled Flyback Converters

In this paper, a feedback compensator (FBC) and a Feedforward compensator (FFC) are proposed to construct a novel compensated peak current mode control pulse width modulation (CPC-PWM) for primary-side controlled flyback converters. Using the proposed FBC, the PWM duty cycle of an abnormal operating flyback converter would be descended to limit the output current for reducing power dissipation. Using the proposed FFC, the effect of delay time would be descended to reduce the over-flow current for increasing the current accuracy. In this paper, the operating principle and mathematical model are described and analyzed. Then, the component values are well designed to satisfy the electrical specifications. Finally, a prototype is designed and realized to access system performance. The experimental results show that the proposed CPC-PWM can validate in a wide input voltage range and output short conditions, which also has good current accuracy and reduces power dissipation by about 68%.

Design Considerations for PPS Controlled Current-Fed DAB Converter to Achieve Full Load Range ZVS and Low Inductor Current Stress

Current-fed dual active bridge dc–dc converters are suited for renewable energy systems such as solar photovoltaic and fuel cells, due to the advantages of small input current ripple and wide input voltage range. In this article, a current-fed dual active bridge dc–dc converter based on pulse width modulation plus phase shift control is studied. The working principle and zero-voltage switching (ZVS) conditions of the converter are analyzed in depth, and it is proved mathematically for the first time that all switches can naturally achieve ZVS independently of dc inductance and leakage inductance under a wide input voltage range within full load range. Based on maximum power transfer, peak current, and root mean square (RMS) current analysis, optimal dc inductance and leakage inductance design to obtain low inductor RMS current is proposed. In addition, the detailed loss breakdown was implemented by comparing it with the nonoptimized case. The effectiveness of the theoretical analysis and design method has been verified by experimental results.

Review of DC-DC Converter Topologies Based on Impedance Network with Wide Input Voltage Range and High Gain for Fuel Cell Vehicles

The development of fuel cell vehicles (FCVs) has a major impact on improving air quality and reducing other fossil-fuel-related problems. DC-DC boost converters with wide input voltage ranges and high gains are essential to fuel cells and DC buses in the powertrains of FCVs, helping to improve the low voltage of fuel cells and “soft” output characteristics. To build DC-DC converters with the desired performance, their topologies have been widely investigated and optimized. Aiming to obtain the optimal design of wide input range and high-gain DC-DC boost converter topologies for FCVs, a review of the research status of DC-DC boost converters based on an impedance network is presented. Additionally, an evaluation system for DC-DC topologies for FCVs is constructed, providing a reference for designing wide input range and high-gain boost converters. The evaluation system uses eight indexes to comprehensively evaluate the performance of DC-DC boost converters for FCVs. On this basis, issues about DC-DC converters for FCVs are discussed, and future research directions are proposed. The main future research directions of DC-DC converter for FCVs include utilizing a DC-DC converter to realize online monitoring of the water content in FCs and designing buck-boost DC-DC converters suitable for high-power commercial FCVs.

Isolated DC–DC Boost Converter for Wide Input Voltage Range and Wide Load Range Applications

A current-fed dual-inductor resonant full-bridge dc–dc isolated boost converter is proposed. The converter is most suitable for applications that demand wide input voltage and load ranges. It can be used as a front-end dc–dc converter that can boost variable low voltage from a power source [battery (home/industrial inverter/industrial UPS application), fuel-cell, or solar-PV] and interface it to a high-voltage dc-link, which typically feeds an inverter. It removes all major drawbacks of conventional current-fed isolated dc–dc converters, namely high-voltage spikes across the switches due to transformer leakage inductance, need for additional start-up circuit, and difficulty in converter tripping in case of faults. Soft-switching of rectifier didoes and clamping power switches is load independent leading to good efficiency over entire load range. Converter can be operated with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> < 0.5, making it suitable for wide input voltage range applications. A detailed comparative analysis with state-of-the-art converters for wide input voltage range applications considering the major important factors, such as power device utilization, transformer utilization, inductive energy requirement, and dc capacitors utilization, confirms the superiority of the proposed converter. Experimental results for a 2.5 kVA inverter application with an input dc voltage range of 90–160 V and output ac voltage of 230 V are provided.

Hybrid T-Type ZVS Pulsewidth Modulation DC–DC Converter

An isolated soft-switching dc–dc converter based on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> -type commutation cell and employing capacitive output filter is introduced in this article. A hybrid switching strategy is proposed, allowing the circuit to operate with a three- or four-level scheme relying on a unique duty cycle definition. The energy transfer process regarding two distinct continuous conduction modes is detailed and a complete static model is derived. Also, the requirements for the occurrence of zero voltage switching (ZVS) on the switches are evaluated, and a small-signal analysis is carried out to provide information on the dynamic behavior of the proposed circuit. The operation of the proposed converter is verified for the conditions of fixed input and output voltage and of wide input voltage range designs. Laboratory tests with a 1.2 kW prototype operating in closed-loop demonstrate the feasibility of the proposed circuit and validate the theoretical analysis carried out.

Synchronous Control Strategy with Input Voltage Feedforward for a Four-Switch Buck-Boost Converter Used in a Variable-Speed PMSG Energy Storage System

The four-switch Buck-Boost (FSBB) converter can produce voltage conversion within a wide input voltage range, which is suitable for variable-speed permanent magnet synchronous generator (PMSG) energy storage systems with AC inputs and DC outputs. To reduce the interference of input voltage fluctuation on the performance of the FSBB converter, an input voltage feedforward (IVFF) compensation method is proposed in this paper. The switching synchronization strategy is simple. Using the switching average model, the small signal model of a non-ideal FSBB converter in all working modes is established. The effects of input voltage, load current, damping coefficient and right half plane (RHP) zero on the stability of the control system are analyzed in detail. The transfer function of the IVFF of the FSBB converter is derived, and the relationship between input voltage, load current and duty cycle is analyzed. Finally, the design of the parameters of the converter control system is presented. The simulation and experimental results show that this FSBB converter has high efficiency and a good transient response.

Conceptualization and Analysis of a Next-Generation Ultra-Compact 1.5-kW PCB-Integrated Wide-Input-Voltage-Range 12V-Output Industrial DC/DC Converter Module

The next-generation industrial environment requires power supplies that are compact, efficient, low-cost, and ultra-reliable, even across mains failures, to power mission-critical electrified processes. Hold-up time requirements and the demand for ultra-high power density and minimum production costs, in particular, drive the need for power converters with (i) a wide input voltage range, to reduce the size of the hold-up capacitor, (ii) soft-switching over the full input voltage and load ranges, to achieve low losses that facilitate a compact realization, and (iii) complete PCB-integration for low-cost manufacturing. In this work, we conceptualize, design, model, fabricate, and characterize a 1.5 kW, 12 V-output DC/DC converter for industrial power supplies that is required to operate across a wide 300 V–430 V input voltage range. This module utilizes an LLC-based control scheme for complete soft-switching and a snake-core transformer to divide the output current with a balanced flux among multiple secondary windings. Detailed loss models are derived for every component in the converter. The converter achieves close to 96% peak efficiency with a power density of 337 W in−3 (20.6 kW/dm−3), excellent matching to the derived loss models, and zero-voltage switching even down to zero load. The loss models are used to identify improvements to further boost efficiency, the most important of which is the minimization of delay times in synchronous rectification, and a subsequent improved 1.5 kW hardware module eliminates nearly 25% of converter losses for a peak efficiency of nearly 97% with a power density of 308 W in−3 (18.8 kW dm−3). Two 1.5 kW modules are then paralleled to achieve 3 kW output power at 12 V and 345 W in−3 (21.1 kW dm−3) with ideal current sharing between the secondary outputs and no drop in efficiency from a single module, an important characteristic enabled by the novel snake-core transformer.

Interleaved Single-Stage LLC Converter Design Utilizing Half- and Full-Bridge Configurations for Wide Voltage Transfer Ratio Applications

Automotive on-board dc-dc converters are required to operate over a wide input and output voltage range depending on the state of charge of the input and the output battery. Conventionally, the unidirectional power transfer between these batteries is enabled by a two-stage converter concept. A first-stage nonisolated dc-dc converter regulates the input voltage of the galvanically isolated second-stage dc-dc converter such that the second-stage converter operates in its optimum operating point. This article presents a single-stage interleaved LLC resonant converter of 3.6 kW for this purpose. While LLC converters are usually not suitable to cover such a wide voltage range (the input voltage between 240 and 420 V and the output voltage between 8 and 16 V), this LLC converter is operated in a full-bridge mode for large gains and in a half-bridge mode for low gains. For intermediate gains and loads, the LLC employs the phase-shift mode. To operate the interleaved LLCs at equal switching frequencies enabling output current ripple cancellation to reduce the output capacitor, again, the phase-shift mode is utilized to balance the power transfer during the full-bridge mode while the asymmetrical duty-cycle mode is proposed for power balancing during the half-bridge mode. This article analyzes the converter design for these modes of operation and provides a comprehensive design procedure allowing the designer to simultaneously analyze all stress values for various resonant tank designs. A 3.6-kW prototype employing Si superjunction MOSFETs achieves a power density of 2.1 kW/L. The maximum efficiency reaches 96.5%, while for most operating points, it is kept well above 90%. The experimental measurement results validate the analysis and show that phase-shift operation and asymmetrical duty-cycle modulation can be utilized for power balancing for full-bridge and half-bridge configurations, respectively, such that a much smaller output capacitor can be employed.