DC-DC Power Converter Research Articles

Development and experimental validation of high-order sliding mode control for quadratic boost converters in fuel cell electric vehicles

The global energy evolution is at a critical juncture, necessitating an urgent transition towards clean and sustainable energy sources, notably green hydrogen, to combat climate change and the inevi-table depletion of fossil fuels. This transition is underscored by the emergence of fuel cell electric vehicles (FCEVs) as a promising solution for clean transportation, demanding advanced DC-DC power converter technologies to ensure their efficiency and reliability. This paper addresses the topic of control for the Quadratic Boost Converter, which presents a challenge due to its non-minimum phase characteristic and nonlinear nature. To tackle this, a nonlinear controller is developed using dual-loop control employing STA-SMC and Lyapunov theory as the control ap-proach. Simulation and experimental validation evaluate the controller's performance, testing ro-bustness against varying load currents and under time-varying reference voltages to assess its ef-fectiveness.

ANALYSIS OF BIDIRECTIONAL DC-DC POWER CONVERTERS FOR SCREENING SYSTEMS OF RETIRED BATTERIES

With the rapid expansion of energy storage technologies, the concept of the second-life battery has become a central element in sustainability and energy efficiency efforts. This innovative approach refers to the further use of batteries, which have reached the end of life, integrating them into applications with lower energy requirements than those in the automotive industry. The batteries must first be evaluated using a screening system that contains a power converter to apply different test profiles and a measurement and control circuit. This article outlines key performance considerations of bidirectional DC-DC power converter topologies and compares them using multi-criteria analysis to determine which design is more suitable for screening systems. The chosen power converters are further studied in the LTspice program for a detailed comparison based on the obtained results.

Enhancing energy efficiency in power looms: utilizing regression machine learning for electrokinetic energy assessment

This study focuses on optimizing electro-kinetic energy utilization in textile weaving units, addressing power interruptions, reducing electrical costs, and harnessing latent kinetic energy during the weaving process. Power looms, vital to textile production, often incur inefficiencies and increased operational costs due to underutilized kinetic energy. To address these challenges, three innovative electrokinetic energy harvesting approaches are proposed: the Modified Series-Parallel Piezo Matrix, bi-directional linear generation, and uni-directional non-linear power extraction methods. The research further incorporates the Super Lift and Ultra Lift DC-DC power conversion techniques to enhance energy efficiency. The Modified Series-Parallel Piezo Array integrates Piezoelectric elements to capture and convert discarded kinetic energy efficiently. The bi-directional linear generation method captures mechanical energy from both forward and backward movements in weaving, minimizing energy wastage. The uni-directional non-linear power extraction method optimizes energy recovery by targeting specific weaving cycle phases. Machine learning algorithms, including Gaussian Process Regression, Linear Regression, Neural Network, and Support Vector Machine, enable precise energy estimation for meticulous modeling and optimization. Rigorous validation through MATLAB simulations aims to bolster energy efficiency, trim operational costs, and promote sustainable energy practices in the textile industry, contributing to a more environmentally friendly and sustainable future for the sector.

A grid-connected eleven-level power conversion interface

ABSTRACT This paper proposes a grid-connected eleven-level power conversion interface (GCELPCI) for renewable power systems. The proposed GCELPCI is composed of a four-port DC-DC power converter (FPDDPC) and an eleven-level inverter (ELI). The FPDDPC combines a boost power converter and a transformer with a turn ratio of 2:1 to generate multiple combinations of the output voltages for the DC bus voltage of the ELI. The ELI integrates an asymmetric voltage technique on a T-type inverter to further convert the DC output voltages of FPDDPC into eleven-level AC voltage. A sinusoidal current is generated by the proposed GCELPCI through the filter inductor and injected into the power grid. Only nine power electronic switches are used in the ELI to generate an eleven-level AC voltage, the number of power electronic switches is reduced to simplify the power circuit. In addition, the capacity of the filter inductor is reduced. A digital signal processor (DSP) and a complex programmable logic device (CPLD) chip are used as the digital controller to complete a hardware prototype to verify the performance of the proposed GCELI.

Full state observer-based pole placement controller for pulse width modulation switched mode voltage-controlled buck Converter

Switched mode DC-DC converters play an important role in today's renewable energy systems, electric Vehicles, consumer electrical appliances, and many more. While many researchers have designed controllers for DC-DC converters, achieving low implementation cost remains a significant hurdle. This paper proposes a cost-effective observer-based pole placement controller for a PWM voltage-controlled Buck converter with clear step by step design approach. The state space averaged model of the DC-DC power converter is used to design pole placement with integrator compensator and full state observer. Pole placement is employed to improve the transient and steady state behavior of Voltage reference tracking response and full state observer is applied to extract the inductor current with the aim of removing the actual current sensor. Design specifications are set to a settling time of less than 5 msec and an overshoot of less than 5 %. While designing Observer-Controller combination, the separation principle, designing the controller and observer independently, is utilized by placing the observer poles far to the left of the controller poles for the Observer to converge faster. The designed controller and observer is verified with simulation in MATLAB/SIMULINK software and design of developed controller and observer are realized using low-cost analog electronics circuit components The results shows that the proposed system's strength in tracking the reference output voltage even in the presence of input voltage disturbance and the mean value of inductor current is well extracted having only the output voltage and MOSFET gate signal.

Impact of Chaos on MOSFET Thermal Stress and Lifetime

The reliability of power electronic switching components is of great concern for many researchers. For their usage in many mission profiles, it is crucial for them to perform for the duration of their intended lifetime; however, they can fail because of thermal stress. Thus, it is essential to analyze their thermal performance. Non-linear switching action, bifurcation and chaotic events may occur in DC-DC power converters. Consequently, they show different behaviors when their parameters change. However, this is an opportunity to study these bifurcation phenomena and the existence of chaos, e.g., in boost converters, on their performance as the effects of load variations (mission profiles) on the system’s behavior. These variations generate many non-linear phenomena such as periodic behavior, repeated period-doubling bifurcations and chaos in the MOSFET drain-source current. Thus, we propose, for the first time, an analysis of the influence of chaos on the junction temperature. First of all, this paper provides a step-by-step procedure to establish an electrothermal model of a C2M0080120D MOSFET with integrated power loss. Then, the junction temperature is estimated by computing the power losses and a thermal impedance model of the switch. Additionally, this model is used to investigate the bifurcation and chaotic behavior of the MOSFET junction temperature. The paper contributes by providing a mathematical model to calculate several coefficients based on experimental data and thermal oscillations. Estimation of the number of cycles to failure is given by the Coffin–Manson equation, while temperature cycles are counted using the rainflow counting algorithm. Further, the accumulated damage results are calculated using the Miner’s model. Finally, a comparison is made between the damage accumulated during different mission profiles: significant degradation of the MOSFET’s lifetime is pointed out for chaotic currents compared to periodic ones.

Direct maximum power injection control of grid-connected PV micro-inverter systems connected to the grid

The increasing use of fossil fuels such as gas and oil has caused many environmental problems, including air pollution, depletion of underground resources, the destructive phenomenon of global warming, destruction of the ozone layer, and many other problems for the environment. Photovoltaic systems are one of the most promising solutions to overcome these problems. Due to the low voltage of solar panels and the higher controllability of photovoltaic systems against changes in sunlight intensity during the day, DC-DC power converters are required. In this project, the aim is to design and build a DC-DC converter with the ability to provide high voltage gain at a suitable efficiency for a 1-string photovoltaic system with the ability to track the maximum power point 2. The designed converter is designed and analyzed with the ability to provide a voltage gain of 5/6 at the critical operating point, a minimum efficiency of 94%, and a power of 500 watts. This converter uses classical soft switching, so the switching losses are reduced, which in turn increases the efficiency of the converter. This converter has a lower voltage stress on the switch (4/0) than the existing techniques. On the other hand, while new converters use a large number of switches and magnetic cores in the cell to provide high gain, this converter uses the least number of switches and magnetic cores to achieve high gain. Also, the passive elements of this converter, such as inductor and capacitor, are in the order of a few microhenries and farads, and therefore the size of these components is also reduced. In addition, due to the high gain provided in lower duty cycles, the efficiency of the switch is increased, and therefore cheaper switches can be used. Also, due to the reduction in the size of passive elements, the size of the magnetic core is also reduced, which in turn optimizes the converter economically.

PSO Training Neural Network MPPT with CUK Converter Topology for Stand-Alone PV Systems Under Varying Load and Climatic Conditions

Temperature and irradiance levels are two examples of environmental variables that affect the power value produced by photovoltaic panels. Therefore, in order to transfer the maximum power value from the PV panel to the load under varying climatic conditions, maximum power point tracking (MPPT) algorithms and DC-DC converter topologies are used. In this study, the performances of boost converter and CUK converter circuit topologies are investigated under variable irradiance and variable load conditions by using a neural network-based MPPT algorithm learning particle swarm optimization (PSO). As the first scenario, it is analyzed assuming that the temperature and irradiance values coming to the panel are constant. As the second scenario, the performance evaluation of the converter topologies according to the current, voltage and power parameters is made for the variable load situation. As the last scenario, the difference in the irradiance value coming to the panel depending on the sun's condition during the day has been examined. Canadian Solar CS6P-250P PV panel is used in the study. 50 kHz is selected as the switching frequency. According to the results obtained, it has been observed that the CUK converter circuit topology reaches the maximum power point faster than the boost converter circuit topology both in dynamic environmental conditions and load change, and the oscillation at this point is less. It is aimed to increase the performance of this method, which uses boost converter topology and MPPT in the literature, by applying CUK converter topology.

Adaptation of Microinverter Reference Design for Integration with Battery Energy Storage Systems in Microgrids

The paper presents an adaptation of the microinverter platform from Texas Instruments to incorporate a battery energy storage system (BESS) alongside the development of the BESS system itself. Initially designed for unidirectional power flow between PV panels and an electric grid, the platform required modifications to accommodate bidirectional energy transfer for BESS integration. These modifications encompass software adjustments and hardware enhancements, which are all detailed within the paper. The electrical configuration includes selecting and deploying components such as DCDC power converters, microcontrollers, measured signals, and actuating signals to facilitate battery connection to the platform’s DC bus. Furthermore, a supervisory control and data acquisition (SCADA) system is devised for supervisory control and monitoring, with its implementation outlined. Control software tailored for the chosen microcontroller of the DCDC converters is described in terms of structure and functionality. A hardware-in-the-loop (HIL) methodology is employed to validate the proposed modifications and microgrid configuration. Utilizing the real-time simulator OPAL-RT, the paper presents experimental results and their analysis within the considered microgrid environment.

Wind Energy Conversion System using Cascading H-Bridge Multilevel Inverter in High Ripple Scenario

This paper presents wind energy conversion system using CHB MLI and phase interleaved boost converter to overcome high voltage and current ripple. Developments in power electronics technology have a direct impact on advances in wind energy conversion systems. WECS output voltage may fluctuate depending on wind speed. For WECS to maintain a constant output voltage, a power converter is required. This paper explains how to configure a phase-interleaved boost converter and voltage controller to maintain a stable intermediate circuit voltage in the system. The proposed cascading H-bridge multilevel inverter (CHB MLI) converts DC/AC using a novel topology. Separate DC sources are not utilizing the suggested topology. Multi-level inverters are operated by specific harmonic disposal pulse width modulation, or SHE-PWM are utilized. PMSG voltage, CHB-MLI voltage, boost converter voltage and rotor speed have seven different levels of simulated waveforms. Among the many advantages of three-phase alternating DC-DC boost converters, that are high efficiency, fast dynamics and very low current ripple. The output voltage is increased to 400 V using a three-phase interleaving converter, which also maintains a higher efficiency of about 98%. DC-DC power converters have proven to be essential components of many applications and topologies. The interleaving technique is necessary to address the main disadvantages of DC-DC power converters: increased voltage, reduced efficiency, and rippled current. Interleaved boost converters have several advantages, including lower switching losses, lower voltage and current ripple, increased efficiency, and more. To improve the converter's overall functionality, the "n" parallel converter is connected through an interleaved boost converter. This paper presents a performance analysis of a multiphase alternating boost converter to reduce high voltage and current ripple. MATLAB/Simulink is used for analysis and simulation of phase-interleaved boost converters.

Maximum Efficiency Point Tracking Algorithm for Resonant Full-Bridge Converter in Charging Applications

In this paper, a novel maximum efficiency point tracking algorithm is proposed for a resonant DC-DC power converter in charging applications. Based on a total harmonic analysis (THA), a method for minimizing the harmonic content of the input AC current is investigated. An online algorithm is proposed for achieving the maximum efficiency at the whole charging spectrum, by controlling the angle under which zero-voltage switching occurs. The suggested control algorithm is simple to implement with very low computational complexity. Additionally, an effective winding method is proposed for increasing the leakage inductance without greatly increasing the air gap, thus eliminating the need for additional resonant inductors. A prototype converter of 2kW|20A is implemented for verifying the proposed method and 98% maximum efficiency is achieved.

A SINGLE STAGE DC-DC CONVERTER FEASIBLE TO BATTERY CHARGING FROM PV PANELS WITH HIGH VOLTAGE STEP UP CAPABILITY

This paper presents a dc-dc power converter integrated in such a way to obtain, in a single conversion stage, the maximum energy extraction from photovoltaic panels, battery charging and discharging dynamic control, and high voltage step-up to feed the inverter DC bus, also operating with soft-switching capability. Although this idea can be applied to most of the high voltage gain topologies, this paper is based on a structure derived from the half-bridge boost converter. Thus, a 500W prototype, with input voltage of 24V and output voltage of 200V, has been developed with the purpose of obtaining the experimental results and validate the proposed converter. High efficiency is achieved, above 92.5%, confirming the expected operation and functionalities necessary for the proposed application.

Microgrids control: AC or DC, that is not the question

In these lecture notes, we delve into the models of the most commonly used DC-DC power converters: namely, the buck converter and the boost converter. Furthermore, we derive models for a DC microgrid consisiting of multiple buck and/or boost converters interconnected via (dynamic) resistive-inductive power lines and supplying the so-called ZIP loads, which are characterized by the parallel combination of constant impedance (Z), current (I), and power (P) load components. Furthermore, we introduce the primary control objectives in DC microgrids, focusing on voltage regulation and current sharing. Finally, we explore the most advanced control techniques to achieve these objectives. Importantly, these lecture notes are not intended to advocate total replacement of Alternating Current (AC) power systems with their Direct Current (DC) counterparts, but rather aim to offer a balanced perspective between them, acknowledging the historical dominance of AC power systems while underscoring the contemporary relevance of DC microgrids, which, with their inherent advantages, represent a viable complement to the existing infrastructure, fostering innovation and resilience in modern power networks.

Optimized Interleaved Ultra-High Gain DC-DC Power Converter With Low Ripple Input Current and Voltage Stress for Fuel Cell Systems

Optimized Interleaved Ultra-High Gain DC-DC Power Converter With Low Ripple Input Current and Voltage Stress for Fuel Cell Systems

Non-Isolated Zeta PWM DC-DC Power Converter Analysis for CCM Including Parasitics

Non-Isolated Zeta PWM DC-DC Power Converter Analysis for CCM Including Parasitics

Online impedance measurement of operational batteries utilizing Sinc function signal injection via DC-DC power converter

This paper presents a novel method for the online impedance measurement of operational batteries that utilizes Sinc function signal injection via a DC-DC power converter. The Sinc function perturbation signal, with its multiple frequency components, enables simultaneous impedance measurement of the battery at various frequencies, thus ensuring high measurement efficiency. Additionally, the generation and injection processes for this perturbation signal are simple and straightforward. Its power spectrum, characterized by a uniform distribution and relatively high power content, enables precise measurements across the entire frequency range of interest. The paper extensively discusses the measurement principle and properties using the perturbation signal, followed by an analysis of the circuit topology to derive the transfer functions, and a simulation to examine the battery’s responses under the perturbation signal. Finally, a case study using a 2.8 Ah 883860-size lithium polymer battery demonstrates the feasibility and accuracy of the proposed method.

Design and Flight Qualification of a Flying Capacitor Multilevel Converter for Electric Aircraft Applications

Multilevel switched-capacitor converters, such as the flying capacitor multilevel (FCML) converter, offer high energy density and efficiency, over a wide voltage range, making them suitable for applications in electrified aircraft. However, concerns of reliability due to the increased number of active and passive components have limited the use of high-level count converters in aircraft applications. This work addresses the challenges of designing a high-level count converter with the goal of extremely high efficiency and power density, with maintained reliability and flight readiness. We present detailed component selection and design techniques to achieve this goal, along with a high-performance 28.2 kW/kg, 99.52% efficient high-voltage dc-dc step-up power converter for experimental validation. Finally, we demonstrate successful completion of critical flight qualification testing of the hardware prototype, including thermal, shock and vibration.

Stability Verification of Neural Network Controllers Using Mixed-Integer Programming

We propose a framework for the stability verification of Mixed-Integer Linear Programming (MILP) representable control policies. This framework compares a fixed candidate policy, which admits an efficient parameterization and can be evaluated at a low computational cost, against a fixed baseline policy, which is known to be stable but expensive to evaluate. We provide sufficient conditions for the closed-loop stability of the candidate policy in terms of the worst-case approximation error with respect to the baseline policy, and we show that these conditions can be checked by solving a Mixed-Integer Quadratic Program (MIQP). Additionally, we demonstrate that an outer and inner approximation of the stability region of the candidate policy can be computed by solving an MILP. The proposed framework is sufficiently general to accommodate a broad range of candidate policies including ReLU Neural Networks (NNs), optimal solution maps of parametric quadratic programs, and Model Predictive Control (MPC) policies. We also present an open-source toolbox in Python based on the proposed framework, which allows for the easy verification of custom NN architectures and MPC formulations. We showcase the flexibility and reliability of our framework in the context of a DC-DC power converter case study and investigate its computational complexity.

Modeling and Control of a DC-DC Buck–Boost Converter with Non-Linear Power Inductor Operating in Saturation Region Considering Electrical Losses

The present work proposes a nonlinear model of a buck–boost DC-DC power converter considering the nonlinear magnetic characteristics of the power inductor and electrical losses of the system. The Euler–Lagrange formalism is used for formulating the proposed model. Previous research works have reported mathematical models to describe power inductor dynamics. However, a gap in the literature remains regarding modeling this kind of element when it operates within power converters. Also, a linear-based controller scheme is proposed to regulate a non-ideal buck–boost DC-DC power converter. A methodology for tuning the proposed controller is presented, which considers the nonlinear model structure of the power converter, the linearization procedure based on an identification process, and a frequency domain analysis based on the approximated linear model. Finally, the tuned control scheme is tested on the nonlinear model of the power converter under several operational conditions showing excellent performance by effectively regulating the output voltage. The results are compared with those derived from alternative control strategies, and a better performance is generally obtained.

Investigation of Key Parameters for Syringe-printing of Nano-silver Paste

Additive manufacturing (AM) techniques, also known as 3D printing, have been embedded into electronic components used for power modules as they can meet complex design requirements with less material waste and shorter lead-time. However, the corresponding manufactural considerations need to be investigated to ensure good printing quality. This paper is a parametric study of previous research [1], specifically focusing on the key parameters for the syringe-printing method that has been used to print a single-layer planar transformer winding implemented on a 10kW DC-DC power converter. A series of key parameters such as kick, trim length, feed rate, and pass spacing are defined, followed by inquiring into the printable regarding the width of a single trace and the gap/printing spacing between two traces. The results indicate that the targeted trace width and gap are subjected to certain errors, resulting in an imprecise actual print, that cannot be employed when designing a CAD model. Instead, a set of recommended values corresponding to the targeted values are acquired. Linear relations between the actual values and targeted values are obtained, which provides convenience for further design when considering using syringe-printing as an AM technique to print nano-silver traces.