Voltage Conversion Range Research Articles

Monolithic design of self-adaptive CMOS converter and robust event-triggered consensus control for integration of multi-renewable energy sources with battery storage system

Recently, integrating renewable energy sources (RESs) has been one of the most effective ways to overcome the power shortage problems due to the cumulative load demand, which cannot be covered using conventional power production. DC-DC converters with a wide voltage conversion range are highly important when integrating RESs to achieve voltage matching. In recent years, many large-scale improvements have been made to the DC-DC converters to improve reliability, effectiveness, flexibility, modularity, and cost-effectiveness. This study investigates the feasibility of integrating RESs and designing the most effective structure using complementary metal-oxide semiconductors (CMOS) for DC-DC converters. A novel monolithic CMOS buck converter with an adaptive sensing feedback system (ASFS) circuit is proposed for renewable integrated systems. The proposed converter based on ASFS provides a wide range of conversion voltages, low cost, and reliability. It depends on the pulse-width modulation (PWM) technique with a voltage-control duty-cycle (VCDC) circuit. The proposed multi-input DC-DC converter is tested to integrate three RESs to form an integrated hybrid system. The proposed converter is built to integrate the PV, wind turbine (WT), wave energy source, and battery energy storage system (BESS). The proposed DC-DC converter is tested to adjust the output voltage of the RESs at 12 V with a load current of 2.4 A to facilitate the integration process. The results show the success of the proposed converter in maintaining the output voltage at 12 V, with maximum efficiency of the CMOS buck DC-DC converter reaching 96.25 % over a wide input voltage range from 15 V to 35 V. Moreover, the maximum peak-peak ripple over the output voltage reaches 600 mV at the maximum input voltage of 35 V. A control method-based event-triggered consensus algorithm has been proposed to regulate the system voltage and ensure active power sharing in the microgrid system. The controller's settling time and rise time have been measured, and a robustness analysis has been performed based on the connections and disconnections of DGs and the impact of faults.

Modified SEPIC DC-DC Converter with Wide Step-up/Step-down Range for Fuel Cell Vehicles

The high efficient buck-boost DC-DC converter with wide step-up/step-down range is the way to solve the issue of voltage matching for commercial fuel cell vehicles with a strong hydrogen-electric hybrid. Based on the conventional SEPIC converter, the negative of one of the capacitors is connected with the negative of the power source to get more energy. A modified SEPIC buck-boost DC-DC converter with the advantages of wide voltage conversion range, continuous input current, common ground, and high conversion efficiency is proposed in this paper, meeting all the requirements of DC-DC converters for commercial fuel cell vehicles. On the basis of the steady-state analysis and comparison, the controller is designed based on the small-signal model. To verify the efficiency of the proposed converter, experimental prototypes are built using Si-based and SiC-based devices respectively. The experimental results show that the proposed buck-boost converter can effectively realize 2/3 times step-down and 5 times step-up. When disturbance and voltage dip occur, the adjust time of the control system is less than 200ms. The controller is verified to be robust and have fast responses. The maximum calculation, simulation and experimental efficiencies all exceed 96%, and the maximum efficiency of the SiC prototype under rated power is 96.1%.

An ultra‐high voltage gain interleaved converter based on three‐winding coupled inductor with reduced input current ripple for renewable energy applications

AbstractThis article proposes an interleaved high step‐up DC–DC converter topology designed for renewable energy applications, featuring an ultra‐high voltage conversion ratio. The converter employs an interleaved structure, resulting in a low peak‐to‐peak ripple in the input source current, which is particularly advantageous for solar PV sources. To enhance the output voltage, the topology utilizes voltage multiplier cells (VMC) and coupled inductor techniques. Two coupled inductors with three windings are integrated into the proposed topology, with the secondary and tertiary windings combined with VMC. This combination effectively reduces the maximum voltage stress across power switches, enabling the use of low‐rated and cost‐effective power switches for implementation. The article offers comprehensive operation modes and steady‐state analyses to demonstrate the converter's performance. A comparison is made between the suggested structure and other similar converter topologies. To validate the mathematical analysis, a 200‐W prototype is constructed, operating at a frequency of 25 kHz and achieving a voltage conversion range of 20 to 409 V. The experimental results are presented to support the findings.

Assessment of Novel Self-tuned Emotional Learning-based Intelligent Controller for Bidirectional Cascaded Quasi-Z-Source DC–DC Converter Control

The self-tuned emotional learning-based intelligent controllers (STELBICs) are suggested to regulate a bidirectional cascaded quasi-Z-source DC-to-DC converters (BC-qZSCs). The bidirectional converters of DC-to-DC with a huge voltage conversion range are required in current times for voltage matching in a variety of applications, particularly electric automobiles. The BC-qZSC may raise or buck the voltage, and electricity flows in both directions. The switch’s duty cycle can be changed to keep the voltage steady. To produce a consistent output voltage, a good controller design is necessary. To enhance the performance of BC-qZSC in both operating modes, this study introduces a unique STELBIC. The proposed novel controller’s performance is evaluated by comparing it with an artificial neural networks-controlled converter and a traditional Proportional Integral-controlled converter. In both boost and buck modes of operation, the controller’s performance is evaluated in terms of voltage quality, including steady-state error, settling time, and voltage ripple. Matlab/Simulink is used to analyze the entire system.

A New Tapped Inductor Buck Converter with Large Step-Down Voltage Conversion

This paper presents a new DC(DC converter with large step-down voltage conversion. The proposed converter is obtained by cascading an input circuit of a Quadratic Buck Converter (QBC) to a Tapped Inductor Buck Converter (TIBC). It uses only one active switch and provides a wider voltage conversion range than other well-known step-down converters. In the paper, the operation of the proposed converter is described. Circuit analysis is performed to derive the voltage gain and key current and voltage equations. The prototype circuit operating with the input voltage of 150 V, the output voltage of 5 V, the load current of 10 A and the switching frequency of 100 kHz is implemented. Experimental results show that the prototype converter exhibits good output voltage regulation and achieves the 30-to-1 voltage step-down operation with a maximum efficiency of 82%. In addition, measurement results confirm that the converter operation is consistent with the theoretical analysis.

Comparative Evaluation of Harmonic Injection Techniques for a Phase-Modular Three-Phase Six-Switch Buck-Boost Y-Inverter

Phase-modular buck–boost dc/ac inverters extend the voltage conversion range of conventional buck-type inverter topologies, and accordingly offer significant advantages for variable-speed motor drives powered from dc sources with wide-voltage-ranges like fuel cells or batteries. In this letter, two new modulation schemes are applied to the six-switch buck–boost Y-inverter (6YI) topology, with an analysis of the efficiency improvement for the proposed third harmonic injection pulsewidth modulation (TPWM) and discontinuous PWM (DPWM) schemes relative to conventional sinusoidal PWM (SPWM). Third harmonic injection PWM (TPWM) substantially reduces conduction losses and discontinuous PWM (DPWM) extends this gain by eliminating high-frequency switching for one-third of the fundamental period. These gains are validated on a 1 kW hardware demonstrator across a dc input voltage from 80 to 240 V, with DPWM reducing total converter losses by 31% over SPWM for a peak efficiency at nominal load of 95.6% with a power density of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$62.3\ {\rm W/in^3}$</tex-math></inline-formula> .

A 7.6-ns Delay Subthreshold Level-Shifter Leveraging a Composite Transistor and a Voltage-Controlled Current Source

A novel level shifter (LS) circuit that uses a new low-power approach based on a parasitic capacitance voltage controlled current source is presented to minimize the propagation delay (PD) and maximize the voltage conversion range. This new scheme uses a simplified circuit including a dependent current source, a composite transistor made of three interconnected n-channel MOSFETs (TnM), one CMOS input inverter, and one CMOS output buffer to provide a fast response time. The circuit utilizes the combined action of the equivalent parasitic capacitance of the TnM, the value of which changes dynamically according to the transient value of the input voltage, and the dependent current source to shift the input signal level up from subthreshold voltage levels to +3.0 V, with minimal delay and power consumption. The LS circuit fabricated in 0.35 μm CMOS technology occupies a silicon area of only 25 μm×25 μm. The LS shows measured rising and falling PDs of, respectively, 4 and 11.2 ns. The measured results show that the presented circuit outperforms other solutions over a wide frequency range of 1 to 130 MHz. The fabricated circuit consumes a static power 31.5 pW and a dynamic power of 3.4 pJ per transition at 1 kHz, V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DDL</sub> =0.8 V, and a capacitive load of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> =0.1 pF.

A multi-path switched-capacitor-inductor hybrid DC-DC converter with reduced inductor loss and extended voltage conversion range

A multi-path switched-capacitor-inductor hybrid DC-DC converter with reduced inductor loss and extended voltage conversion range

A bidirectional hybrid switched inductor converter with wide voltage conversion range

A bidirectional hybrid switched inductor converter (BHSI) is proposed in this paper. The converter uses an inductor switching cell in order to achieve a wide voltage conversion range, smaller passive components, and lower stress on the active devices. Apart from these advantages, the introduction of the additional inductor in the switching cell does not increase the complexity of the control structure, as is usually the case with other topologies with multiple components. The BHSI is compared, in terms of inductor/capacitor energies and total device stress, to other state-of-the-art topologies and its advantages are highlighted. Two 3 kW prototypes were built, using Si-MOSFETs and GaN-FETs, in order to analyse their performances from the efficiency point of view, and to validate the theoretical findings. The stability analysis of the converter is performed and tested in a supercapacitor storage application, resulting in a good operation in both charge and discharge modes.

Buck–Boost Three-Level Semi-Dual-Bridge Resonant Isolated DC–DC Converter

The semi-dual-bridge resonant isolated dc–dc converter (SDBRC), as a class of emerging topologies, is suitable for the application situation that requires only the unidirectional power transfer while a wide buck–boost voltage conversion range. In this article, a three-level SDBRC is proposed. Its operation principle is analyzed, and the transfer power and voltage conversion ratio as the functions of the two phase shifts are derived. Furthermore, a coordinated control rule of the two phase shifts is proposed, which ensures the monotonicity between the phase shifts and the average output power over the entire power/voltage range. The voltage stress of the power devices of the proposed topology is reduced to half of the power supply voltage; therefore, the cost and ON-state loss of the power switches are effectively reduced. The detailed simulation and experimental results validate the correctness and feasibility of the proposed topology and its modulation strategy.

Wide-range energy-efficient buffer-based voltage level-up converters for multi-supply voltage systems

The voltage level converters (LCs) are required to attain optimized power consumption by interfacing two or more supply voltage domains in Systems-on-Chip (SoC) applications. The voltage level-up conversion can be easily and effectively achieved by the use of buffer structures. Hence this article proposes two buffer-based LCs, namely transmission gate buffer level converter (TGBLC) and stacked PMOS buffer level converter (SPBLC), based on voltage stepping technique. The energy-efficient transmission gate (TG) and stacked PMOS (SP) structures are proposed to define voltage steps in the buffer and ensure a wider voltage conversion range with high speed. The LCs are implemented in 0.18 $$\mu $$ m technology and their performance metrics are verified using a Spectre circuit simulator. The simulation results show that TGBLC and SPBLC can convert a low input voltage of 600 and 550 mV to 1.8 V, respectively. For the target input voltage of 0.8 V with frequency of 1 MHz, the TGBLC and SPBLC exhibit an improved delay of 7.3 and 7.1 ns with an energy consumption of 9.66 and 6.66 pJ per transition, respectively. It is noted from the experimental results that the proposed LCs are suitable for applications where simplicity and energy efficiency/low power with a wider conversion range is preferred.

Modeling, Design, Analysis, and Control of a Nonisolated Universal On-Board Battery Charger for Electric Transportation

On-board chargers (OBCs) in electric transportation resolve the anxiety for frequent charging of the battery packs. This paper presents a single-phase nonisolated OBC for electric transportation using a two-switch topology. The main advantage of this OBC is that it can perform high input power quality over a wide output voltage conversion range. The presented two-switch converter is able to operate with an output voltage above and below the peak of input voltages. The analysis and various operating modes of converter and design considerations to achieve the wide output voltages are discussed in this paper. Moreover, small-signal analysis of the converter in various modes to aid for the design of the controller is also presented. A two-mode control scheme with average current-mode (ACM) control structure using PI controllers is shown in this paper with a feature of automatic mode selection. As a proof of concept, the experimental results from a 1-kW laboratory prototype with an output voltage range of 150–450 V are presented. A high input power factor of 0.99 and an efficiency of 96% have been achieved from the prototype.

Optimised phase shift control to minimise current stress of three‐level dual active bridge DC–DC converter

The current stress of three-level dual active bridge (3L-DAB) converter under the conventional phase shift (CPS) control becomes much high, especially when the voltage conversion ratio is unequal to one, which may bring low efficiency and damage of power devices. An optimised phase shift (OPS) control strategy is presented to address the issue. The OPS control is realised by calculating the optimal operation point with real-time detection of voltages and current. The principle of 3L-DAB under CPS control is presented. The mathematical models of transmission power and current stress are then established. The minimum current stress and the corresponding optimal phase shift ratios are deduced within different ranges of transmission power and voltage conversion ratio, the comparative analysis of current stress and reflux power under OPS and CPS controls have been carried out. The current stress is minimised with any given transmission power and voltage conversion ratio in the whole power range after adopting the OPS control strategy. Moreover, the reflux power is reduced as well within the boundary of voltage conversion range. An experimental prototype was developed to verify the effectiveness of the proposed control strategy and the correctness of the theoretical analysis.

Three‐state switching cell (3SSC)‐based non‐isolated dc–dc boost‐type converter with balanced output voltage and wide voltage conversion range

This work presents a non-isolated step-up dc–dc converter with wide voltage conversion range based on the three-state switching cell, which is suitable for distinct applications, e.g. renewable energy and uninterruptible power supply (UPS) systems. Prominent advantages can be addressed to the topology, i.e. continuous input current, thus making it a proper choice for the use of battery banks as the input voltage source; the ability to operate at high power, high-current levels while maintaining current sharing through the main switches without the need of special control schemes; reduction of size, weight, and volume of filter elements, which are designed for twice the switching frequency; the maximum voltage across the controlled switches is half of the total output voltage; naturally balanced voltages across the dc-link capacitors exist; and the voltages across the switches are naturally clamped to that across the output filter capacitor, avoiding the need for external snubbers. The complete qualitative analysis of the converter is presented, including the operating principle and a step-by-step design procedure. A transformerless online UPS topology is also briefly described as a potential application for the introduced converter. Finally, experimental waveforms obtained from a 1.55-kW prototype are shown and relevant issues are discussed.

A Bidirectional Three-level DC-DC Converter with a Wide Voltage Conversion Range for Hybrid Energy Source Electric Vehicles

In order to meet the increasing needs of the hybrid energy source system for electric vehicles, which demand bidirectional power flow capability with a wide-voltage-conversion range, a bidirectional three-level DC-DC converter and some control strategies for hybrid energy source electric vehicles are proposed. The proposed topology is synthesized from Buck and Boost three-level DC-DC topologies with a high voltage-gain and non-extreme duty cycles, and the bidirectional operation principle is analyzed. In addition, the inductor current ripple can be effectively reduced within the permitted duty cycle range by the coordinated control between the current fluctuation reduction and the non-extreme duty cycles. Furthermore, benefitting from duty cycle disturbance control, series-connected capacitor voltages can also be well balanced, even with the discrepant rise and fall time of power switches and the somewhat unequal capacitances of series-connected capacitors. Finally, experiment results of the bidirectional operations are given to verify the validity and feasibility of the proposed converter and control strategies. It is shown to be suitable for hybrid energy source electric vehicles.

Multitrack Power Conversion Architecture

This paper introduces a MultiTrack power conversion architecture that represents a new way of combining switched capacitor circuits and magnetics. The MultiTrack architecture takes advantages of the distributed power processing concept and a hybrid switched-capacitor/magnetics circuit structure. It reduces the voltage ratings on devices, reduces the voltage regulation stress of the system, improves the component utilization, and reduces the sizes of passive components. This architecture is suitable to dc- dc and grid-interface applications that require both isolation and wide voltage conversion range. An 18-80 V input, 5 V, 15 A output, 800 kHz, 0.93 in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (1/16 brick equivalent) isolated dc-dc converter has been built and tested to verify the effectiveness of this architecture. By employing the MultiTrack architecture, utilizing GaN switches, and operating at higher frequencies, the prototype converter achieves a power density of 457.3 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and a peak efficiency of 91.3%. Its power density is 3× higher than the state-of-the-art commercial converters with comparable efficiency across the wide operation range.

An Ultra-Low Voltage Level Shifter Using Revised Wilson Current Mirror for Fast and Energy-Efficient Wide-Range Voltage Conversion from Sub-Threshold to I/O Voltage

This paper presents a novel ultra-low voltage level shifter for fast and energy-efficient wide-range voltage conversion from sub-threshold to I/O voltage. By addressing the voltage drop and non-optimal feedback control in a state-of-the-art level shifter based on Wilson current mirror, the proposed level shifter with revised Wilson current mirror significantly improves the delay and power consumption while achieving a wide voltage conversion range. It also employs mixed-Vt device and device sizing aware of inverse narrow width effect to further improve the delay and power consumption. Measurement results at 0.18 μm show that compared with the Wilson current mirror based level shifter, the proposed level shifter improves the delay, switching energy and leakage power by up to 3×, 19×, 29× respectively, when converting 0.3 V to a voltage between 0.6 V and 3.3 V. More specifically, it achieves 1.03 (or 1.15) FO4 delay, 39 (or 954) fJ/transition and 160 (or 970) pW leakage power, when converting 0.3 V to 1.8 V (or 3.3 V), which is better than several state-of-the-art level shifters for similar range voltage conversion. The measurement results also show that the proposed level shifter has good delay scalability with supply voltage scaling and low sensitivity to process and temperature variations.

Energy Efficient Voltage Conversion Range of Multiple Level Shifter Design in Multi Voltage Domain

Level shifter is inserted between two modules when low voltage drives high voltage modules. Multi supply voltage is used to reduce the static and dynamic power consumption. Multi supply voltage domain technique consists of portioning the design into separate voltage domain. So the time critical domain runs at higher power supply voltage where non-critical domain is runs at lower power supply voltage. The conventional differential cascade voltage switch is the level shifter circuit. The conventional multi threshold CMOS (MTCMOS) greatly reduces the leakage power. But it does wide voltage conversion range is not achieved in level shifter design. So we use a multiple level shifter instead of single level shifter with multi threshold CMOS device. The multiple level shifter design can be achieved the conversion voltage range of 1V to 1.8V. The inter mediate power supply voltage of level shifter contains 400mV,600mV.800mV ranges of operation. It can be designed by using cadence 180nm technology. The synthesis results can be achieved in 310^W power supply.

Static performance and parasitic analysis of tapped‐inductor converters

Tapped-inductor provides the property of wider voltage conversion range similar to an auto-transformer and can be integrated to a switched-mode power converter to enhance the power conversion efficiency. Its low component count has attracted applications with extreme voltage conversion ratios. Circuit family is presented and a general tapping concept for diode, transistor or both has been described. Its boost converter version is used as an example for the study. Detailed comparisons between tapped-inductor boost and conventional boost are carried out, which include the comparison of voltage gain, component stress and efficiency with the presence of the parasitic components. Experimental results present solid verification of the analysis of performance of tapped-inductor boost converter under extreme conversion ratios. The proposed study has introduced formulations for both transistor and diode tapping and can be extended to other tapped-inductor DC-DC converters as a family of circuits, and thus provides an understanding of the effect of the parasitic components that affect the efficiency under extreme conversion ratio.

A dual-path, current-sensing resistor-free boost LED driver with fast PWM dimming

A boost LED driver featuring a high PWM dimming ratio and optimized efficiency is presented. This LED driver, which has a low dropout voltage and is able to drive 3–7 LEDs in series with constant output current and fast PWM dimming, provides an alternative technique for brightness adjustment. A dual-path control scheme with automatic switching and state maintenance is proposed. Meanwhile, a cascode current mirror structure is applied with the output transistor multiplexed as an LED PWM dimming transistor. Implemented in 0.5 μm 25 V BCD process, the measurement results show that a voltage conversion range of 5 V input to 6–24 V output with constant output current is obtained. With automatically switching dual-path control and an optimized current mirror, the response time during PWM dimming is reduced to as low as 240 ns and the efficiency keeps above 89% over a wide PWM dimming ratio @ 250 mA output current.