Synchronous Buck Converter Research Articles

Analysis and Design of an SiC CMOS Three-Channel DC-DC Synchronous Buck Converter for High-Temperature Applications

In this study, we present the design, simulation, and implementation of a DC-DC synchronous buck converter utilizing IISB’s 2 μm 4H-silicon carbide (SiC) complementary metal–oxide–semiconductor (CMOS) technology. The converter is designed to meet the demands of modern integrated circuits, particularly in the field of integrated power management. The SiC technology offers enhanced performance and reliability at high temperatures, making it especially suitable for applications that operate in these conditions, including automotive systems, and aerospace, among others. The power transistors and gate drivers are fully integrated on-chip, optimizing efficiency and minimizing footprint. Additionally, the study contributes to the understanding of SiC technology and its application in integrated circuit design. Simulation results demonstrate a peak efficiency of 86.6% at 120 mA load current and 84.8% at 300 mA load current, showing the converter performance under different operating conditions. Furthermore, at high temperatures (295 °C), the converter achieves an efficiency of 89.6%, demonstrating its robustness and versatility in extreme environments. These findings contribute to the advancement of integrated circuit design and facilitate advancements in more efficient and robust power management solutions.

Digital Active EMI Filter for Smart Electronic Power Converters

Electronic power converters are widespread and crucial components in modern energy scenarios. Beyond mere electrical energy conversion, their electronic structure allows several functionalities to be naturally embedded in them, including energy management, diagnosis, communication, etc. The operation of the converter itself, or the system interfaced by the same, commonly produces undesired electromagnetic interferences (EMIs) that should comply with prescribed limits. This paper presents a digital active EMI filter designed to mitigate such disturbances. The proposed hardware implementation can acquire and analyze the common-mode (CM) noise affecting the circuit and inject a compensation signal to attenuate the measured interference. A novel adaptive algorithm is introduced to compute the necessary signals for effective noise cancellation. The implementation is integrated within a single printed circuit board interfaced with a field-programmable gate array (FPGA) running the control algorithm. The digital filter’s efficacy in EMI reduction is demonstrated using a synchronous buck converter with gallium nitride (GaN) power devices, achieving significant noise reduction. Additionally, potential functionalities are envisioned to fully exploit the capabilities of the proposal beyond EMI filtering, like fault detection, predictive maintenance, smart converter optimization, and communication.

Deep Reinforcement Learning using Deep-Q-Network for Global Maximum Power Point Tracking: Design and Experiments in Real Photovoltaic Systems

This paper presents a methodology for integrating Deep Reinforcement Learning (DRL) using a Deep-Q-Network (DQN) agent into real-time experiments to achieve the Global Maximum Power Point (GMPP) of Photovoltaic (PV) systems under various environmental conditions. Conventional methods, such as the Perturb and Observe (P&O) algorithm, often become stuck at the Local Maximum Power Point (LMPP) and fail to reach the GMPP under Partial Shading Conditions (PSC). The main contribution of this work is the experimental validation of the DQN agent’s implementation in a synchronous DC-DC Buck converter (step-down converter) un- der both uniform and PSC conditions. Additionally, we establish a testing pipeline for DRL models. The DQN agent’s performance is evaluated alongside the P&O algorithm. Results consistently indicate the DQN agent’s superiority over the P&O algorithm in all simulated scenarios. Although this trend does not entirely replicate in real-world test setups, significant results are observed. Specifically, in PSC sce- narios where the P&O algorithm becomes trapped at an LMPP, the DQN algorithm extracts up to 63.5% more power than the P&O algorithm. An open repository is available, containing PCB schematic designs and layouts, along with the code used for model training and deployment.

SPICE Simulation Assisted-Dynamic Rds(on) Characterization in 200V Commercial Schottky p-GaN HEMTs Under Unstable Phases

Abstract This paper presents a comprehensive analysis of dynamic and static RDS(ON) in Schottky p-GaN High Electron Mobility Transistors (HEMTs), highlighting the impact of off-state and hot electron trapping on device performance. The authors observed significant hysteresis in the transfer characteristics of a 200V commercial Schottky p-GaN, attributing this to charge trapping effects. A novel experimental setup, employing a multi-pulse test synchronous buck converter circuit with additional gate control and a clamping circuit, enabled precise characterization of dynamic RDS(ON) under varying conditions, including unstable phases with overcurrent. This method effectively mimics solar PV input scenarios, exposing the device to high dv/dt and di/dt stresses, which are critical for evaluating GaN device stability under transient conditions. This research also reveals that increased gate resistance reduces energy losses, challenging traditional expectations by demonstrating the nuanced gate charge dynamics of GaN HEMTs. This study overall contributes to the understanding of GaN device behavior, offering a novel approach for accurately characterizing dynamic RDS(ON) under unstable stages, furtherly advances the GaN device in complex renewable energy power converter applications.

A non-isolated synchronous buck DC-DC converter, ZVS topology under CCM and DCM conditions

Today, the main challenge of miniaturization and integration of power converters is reducing the volume of parts, eliminating capacitors and inductors.This paper proposes a non-isolated synchronous buck converter (NSBC) under soft switching practice. This converter uses the zero voltage switching (ZVS) topology, which not only provides soft-switching conditions for the converter switches but also prevents the voltage kicking off the two ends of the main switches from being off-state due to self-resonance. To achieve the highest voltage gain in different working cycles, complementary switching approach and use of non-isolated Dc-Dc converter for simultaneous switching of two switches will be used.The non-isolated synchronous buck DC-DC converter with ZVS is to use in some parts of the converter for providing a purpose range of output voltage. In addition, the implementation of the proposed converter control circuit is conducted very simply and needs lower costs. To confirm relations in converter theory, the results of a laboratory sample in the discontinuous and continuous modes are examined. It should be noted that the proposed converter can operate under different levels of voltage, which requires a protection heat policy. The proposed converter implements under the nominal 30-V input and 40 KHz switching frequency, which touches on issues on both sides of discontinuous conduction mode (DCM) and the continuous conduction mode (CCM) conditions and experiment as an example two rates of power 30W and 20W respectively, and also has an acceptable interest rate, which will be evaluated and compared with three different types of similar modes.

SPICE Modelling-Assisted evaluation of dynamic on-resistance characterization in Schottky p-GaN HEMTs amid synchronous buck transient instabilities

This study addresses the critical gap in dynamic on-resistance characterization for GaN HEMTs within the initial unstable state in a non-isolated DC-DC converter, where the output voltage and currents fluctuate and exhibit overshoots or undershoots before stabilizing to their steady-state values, a domain within solar photovoltaic (PV) Maximum Power Point Tracking (MPPT) implementations which is crucial yet insufficiently examined. The authors present a novel multi-pulse test circuit within a synchronous buck converter configuration, complemented by SPICE simulation. This combination allows for the accurate assessment of clamping circuits' performance during transient states, significantly improving the precision of RDS(ON) measurements in unsteady phases. The approach deviates from conventional methods by merging empirical data with simulation insights to validate the efficacy of clamping circuits. The experimental results affirm the methodology's precision, with the highlighted Circuit V showcasing a marginal deviation of 2.32 % from existing benchmarks. This finding substantiates the method's dependability and practicality contributing to the GaN power electronics field. In addition, this research provides a powerful analytical tool for RDS(ON) evaluation, culminating in the design of a test PCB that synergizes with both simulated and empirical evidence, contributing future research in GaN HEMT power converter applications.

Voltage regulation in an interleaved circular chain sliding mode controlled multiphase converter

In this article a multiphase synchronous buck converter controlled by a sliding mode control (SMC) in a circular chain control (CCC) configuration is presented. The proposed switching functions with the CCC architecture ensure a robust output voltage regulation when facing changes in the load or the input voltage, while providing current equalization among the phases. The novelty of the work is the simple control structure based on a first order SMC implemented by means of hysteresis-band comparators, requiring no external signals or additional hardware to lead the system to an interleaving operation, obtaining a harmonic cancellation that allows the size reduction not only of the output capacitor but also of the inductors. It is proved that, in the steady state, the switching function exhibits a periodic solution with a period equal to the switching period. Besides, the steady-state switching frequency expression as a function of the hysteresis bandwidth is derived. The work includes the analytical analysis of the proposed solution, a set of numerical simulations and, finally, an experimental validation. The numerical and experimental results confirm the predicted good performance of the proposed control.

Modeling dynamic power generation from ocean waves in the Kingdom of Tonga: A comprehensive analysis using integrated mechanical and electrical framework

Globally, ocean wave energy can significantly reduce carbon dioxide emissions from the electricity generation sector. Wave energy converters (WECs) could be installed in the Kingdom of Tonga, which is surrounded by ocean, where the average wave energy flux is greater than 7 kW/m. There is a lack of feasibility studies in this area due to the unavailability of measured data on wave parameters and properties; hence, the potential of WEC is yet to be discovered or exploited. This study proposes an integrated mechanical and electrical modeling framework to analyze the impact of wave characteristics on dynamic power generation in three main islands of Tonga, including ‘Eua, Tongatapu, and Niuafo’ou. The mechanical simulation involves using a 2D Fourier wave model to identify the important factors that affect the power potential of ocean waves, such as wave height and period. The wave model is linked to a comprehensive electrical simulation model developed in Matlab Simulink, which includes a permanent magnet linear synchronous generator (PMLSG), rectifier, buck converter, inverter, and load to estimate the electrical power potential per 1 m2 of ocean area. According to the findings, in ‘Eua, the maximum annual generation intensity output is 90.45 kWh/m2, whereas in Niuafo'ou, the minimum is 48.5 kWh/m2. Applying this to a region (12.57 m2) where a WEC has been deployed in Australia, the highest yearly electricity generation in ‘Eua ranges between 926.41 and 1136.96 kWh/y, but in Tongatapu and Niuafo'ou, it ranges between around 610 and 899 kWh/y.

Implementing Different MPPT Algorithm For Solar Charge Controller

In this paper, MPPT methods such as Perturb and Observe (P and O), Incremental Conductance and Fractional open Circuit Voltage method has been studied. Also, two converter topology, Buck and Synchronous buck converter has been Studied. Hardware implementation of the solar charge controller is done based on the software simulation data and results. Hardware is developed for 1kW system and 48V, 100Ah battery is going to be charged with it. Two MPPT method with synchronous buck converter has been implemented in hardware. This designed hardware has been tested with different irradiance condition. This proposed system can be used in golf cart to make it a stand-alone system with taking care of all protection measures.

Examination and experimental comparison of dc/dc buck converter topologies used in wireless electric vehicle charging applications

The studies on Wireless Power Transfer (WPT) technology and peripherals in Electric Vehicle (EV) applications are intensifying. While the energy received from the WPT system is transferred to the EV battery, the direct current (dc)/dc converter circuits are used. The dc/dc buck converter topologies are one of them. The converter circuits must be highly efficient, lightweight, and compact to have a high range in EV vehicles. There are asynchronous buck, synchronous buck, and interleaved synchronous buck converter circuit topologies from the literature. In this study, the efficiency results of these circuit topologies were analyzed using MATLAB/Simulink and experimental studies. This study contributes to the literature by conducting circuit-level efficiency analysis and component-level power loss analysis. It has been observed that the interleaved synchronous buck converter circuit operates at 99% efficiency at 1066 W. In addition, it has been shared with the oscilloscope results that the current ripples of this circuit topology are lower than other circuit converters. Specifically, there has been a significant reduction of 56% in power losses, particularly in the interleaved synchronous buck converter (ISBC). This study analyzes the dynamic behavior of the dc/dc buck converter topologies, and results about their performance are given.

A novel driver circuit of SiC MOSFET for suppressing crosstalk voltage in bridge circuit

Due to the presence of crosstalk voltage in the circuit, SiC MOSFET devices can be damaged or misled. Suppressing crosstalk voltage makes it an important step for the circuit to function properly. This article first delves into the causes of crosstalk voltage generation. The main research object is synchronous Buck converters, and the reasons for the crosstalk voltage of SiC MOSFETs are analyzed. Afterwards, a novel drive circuit was designed to suppress crosstalk voltage, and the working principle of this drive circuit was analyzed. Finally, simulation was conducted using LTspice software to study and analyze the simulation results, proving the feasibility of this novel drive circuit for suppressing crosstalk voltage, and demonstrating the advantages and disadvantages of this novel drive circuit for suppressing crosstalk voltage.

Evaluation of custom-designed lateral power transistors in a silicon-on-insulator process in a synchronous buck converter

Most of todays power converters are based on power semiconductors, which are built in vertical power semiconductor processes. These devices result in limited packaging possibilities, which lead to physically long galvanic connections and therefore high external electromagnetic fields. These fields compromise power quality significantly. Therefore this paper examines the possibility to use lateral silicon-on-insulator power MOSFETs and uses the custom-made devices in a 48 V to 12 V synchronous buck converter in continuous conduction mode. The converter is designed based on custom made power transistors, implemented and verified by experimental results. The resulting efficiency of the 1 Wconverter is around 93 % across a wide load range and its temperature rise is less the 10 C. This leads to the conclusion, that modern lateral silicon-on-insulator power processes allow high integration of power stages and therefore promise lower emissions, leading to higher power quality.

An Integrated Driver with Dual-Edge Adaptive Dead-Time Control for GaN-Based Synchronous Buck Converter

An Integrated Driver with Dual-Edge Adaptive Dead-Time Control for GaN-Based Synchronous Buck Converter

Energy Conversion Optimization Method in Nano-Grids Using Variable Supply Voltage Adjustment Strategy Based on a Novel Inverse Maximum Power Point Tracking Technique (iMPPT)

This paper introduces a novel power supply voltage adjustment strategy that can determine the optimum voltage value based on the amount of absorbed power. The novel automatic voltage adjustment technique was called inverse maximum power point tracking (iMPPT). The proposed control strategy consists of a modified maximum power point tracking (MPPT) algorithm (more precisely the P&O method). In this case, the modified MPPT technique establishes the minimum value of the input absorbed power of a consumer load served by a switched-mode power supply (SMPS). The iMPPT adjusts the input power by modifying the input voltage of the main power supply. The served loads are connected to the variable power supply via an interfacing power electronics converter that performs the automatic voltage regulation function (AVR). The optimal value of the input voltage level can be achieved when the input power of the automatic voltage regulation converter is at a minimum. In that case, the energy conversion efficiency ratio is at a maximum, and the overall losses related to the front-end power stage are at a minimum. The proposed technique can also be considered a Maximum Efficiency Tracking (MET) method. By performing the inverse operation of a maximum power point tracking algorithm on the input demanded power of a switched mode power supply (SMPS), the optimum input voltage level can be determined when the maximum energy conversion ratio (related to a given load level) is achieved. The novel proposed iMPPT method can improve the energy conversion ratio from 85% up to approximately 10% in the case of an output power level of 800 W served by a synchronous buck converter at the input voltage level of 350 V. The total amount of recovered power in this situation can be approximately 100 W.

Design Considerations of Multi-Phase Buck DC-DC Converter

The main objective of this article is to propose a rational methodology for designing multi-phase step-down DC-DC converters, which can find applications both in engineering practice and in power electronics education. This study discusses the main types of losses in the multi-phase synchronous buck converter circuit (transistors’ conduction losses, high-side MOSFET’s switching losses, reverse recovery losses in the body diode, dead time losses, output capacitance losses in the MOSFETs, gate charge losses in MOSFETs, conduction losses in the inductor, and losses in the input and output capacitors) and provides analytical dependencies for their calculation. Based on the control examples for applications characterized by low voltage and high output current, the multi-phase buck converter’s output and input current ripples are analyzed and compared analytically and graphically (3D plots). Furthermore, graphical results of the converter efficiency at different numbers of phases (N = 2, 4, 6, 8, and 12) are presented. An analysis of the impact of various parameters on power losses is conducted. Thus, a discussion on assessing the factors influencing the selection of the number of phases in the multi-phase synchronous buck converter is presented. The proposed systematized approach, which offers a fast and accurate method for calculating power losses and overall converter efficiency, reduces the need for extensive preliminary computational procedures and achieves optimized solutions. Simulation results for investigating power losses in 8-phase multi-phase synchronous buck converters are also presented. The relative error between analytical and simulation results does not exceed 4%.

A novel in-situ approach to monitor the variations in the on-resistance of power transistors during switching operation

We propose a novel in-situ approach for monitoring the variations in the on-resistance of power transistors in switching-mode operation. The device under test (DUT) is operated in a synchronous buck converter; a feedback loop, acting on the duty cycle of the DUT, is used to keep the output voltage constant, even in presence of variations of device properties. An increase in the equivalent resistance of the DUT is sensed by monitoring the variation of the duty cycle during operation, through an oscilloscope-based setup. The test is “in-situ” since device operation does not need to be interrupted for sensing the variations in on-resistance. The effectiveness of the proposed approach is verified by evaluating the increase in on-resistance induced by the self-heating of a silicon MOSFET. This approach can be useful to evaluate changes in the on-resistance of FETs induced by long-term reliability tests, or by a variation in device heating induced by a variation in the thermal resistance of the devices. In addition, the same approach can be used also for evaluating the impact of charge-trapping phenomena in novel technologies, based on novel semiconductors as SiC and GaN.

Fuzzy control of synchronous buck converters utilizing fuzzy inference system for renewable energy applications

<p>In the present research, an innovative fuzzy control approach is developed specifically for synchronous buck converters utilized in renewable energy applications. The proposed control strategy effectively manages load changes, nonlinear loads, and input voltage variations while improving both stability and transient response. The method employs a fuzzy inference system (FIS) that integrates adaptive control, feedforward control, and multivariable control to guarantee optimal performance under a wide range of operating conditions. The design of the control scheme involves formulating a rule base connecting input variables to an output variable, which signifies the duty cycle of the switching signal. The rule base is configured to dynamically modify control rules and membership functions in accordance with load conditions, input voltage fluctuations, and other contributing factors. The performance of the control scheme is evaluated in comparison to conventional techniques, such as proportional integral derivative (PID) control. Results indicate that the advanced fuzzy control approach surpasses traditional methods in terms of voltage regulation, stability, and transient response, particularly when faced with variable load conditions and input voltage changes. As a result, this control scheme is highly compatible with renewable energy systems, encompassing solar and wind power installations where input voltage and load conditions may experience considerable fluctuations. This research highlights the potential of the proposed fuzzy control approach to significantly enhance the performance and reliability of renewable energy systems.</p>

Optimization of Minimum Negative Current BCM Synchronous Buck Converter

Non-isolated DC-DC converters are widely used in renewable energy applications, such as the hybrid energy storage system (HESS), charging and discharging system of batteries and supercapacitors and the photovoltaic power generation. With the advantages of achieving zero-voltage-switching (ZVS), high efficiency and power density, low cost, and fast dynamic response, the converters operating in boundary current mode (BCM) have caught researchers' eyes recently. Taking the synchronous buck converters as an example, this paper briefly introduces the working principle and advantages of BCM converter realize soft switching. Firstly, it is pointed out that the phenomenon of circulating energy exists in the BCM converter. Then, the relationship between circulating energy and negative current is analyzed, and an optimal control strategy of negative current minimization is proposed to reduce the circulating energy. In the condition of realizing ZVS, negative current minimization not only improves the efficiency of the converter, but also reduces the ripple of inductor current to a certain extent. Finally, the experimental platform of 100 W synchronous buck converter is built. Experimental results validate that the optimal control of minimum negative current has good effect on improving efficiency of converter and reducing the ripple of inductor current.

Design and analysis performances of a 3.6 kW new three-phase charger based on synchronous buck converter with low harmonic distortion for urban cars

Design and analysis performances of a 3.6 kW new three-phase charger based on synchronous buck converter with low harmonic distortion for urban cars

Output Voltage Drop and Input Current Ripple Suppression for the Pulse Load Power Supply Using Virtual Multiple Quasi-Notch-Filters Impedance

To balance the instantaneous power difference between the pulsed output power and the constant input power of the pulse load power supply (PLPS), an active capacitor converter (ACC), which can compensate the pulsed current, is connected in parallel with the output of the dc-dc converter in the PLPS. In this paper, based on the Fourier decomposition results of the load current, it is evident that square waves have significant harmonic content. Hence, to provide the lower impedance at the frequencies of the high content harmonics in the load current, a virtual impedance that consisted of the multiple quasi-notch-filters (MQNF) is proposed to be in parallel at the port of the ACC for the suppression of output voltage drop and input current ripple. The virtual parallel impedance is implemented by the output voltage feedforward control (FFC) of the ACC. The design considerations of the virtual parallel impedance are presented to ensure the stability of the PLPS. Finally, a synchronous rectifier buck (SR-buck) converter with a bidirectional buck/boost converter is tested at the pulse repetition frequency (PRF) of 100-300 Hz and the pulse duty cycle of 0.15 to verify the validity of the proposed control scheme.