Switching Losses Of Converter Research Articles

Optimizing renewable energy utilization with high gain converters

This research proposes a novel control technique for optimizing hybrid renewable energy sources (HRES) by using a high-gain DC-to-DC converter topology. The Hybrid RES system comprises a battery components, wind turbine (WT), and photovoltaic (PV). The proposed control methodology utilizes an enhanced jellyfish search (EJS) controller, which enhances the search behavior of the jellyfish search algorithm through the incorporation of mutation and crossover operators. The converter is designed to maximize efficiency, minimize switching losses, and effectively utilize renewable energy. To achieve optimal performance, a dataset with optimum gain values is constructed using a minimal error target function and proportional-integral (PI) controller gain parameters. The EJS algorithm determines the PI controller gain based on the error in reactive and active power. Randomly generated gain values are used as inputs to the system, and the algorithm adjusts the PI settings by minimizing system error and optimizing power flow management. The inclusion of batteries helps balance renewable power and enhances output consistency. The proposed system is implemented in MATLAB and is compared with existing systems. The novelty of this research lies in the combination of the EJS algorithm with converter efficiency, switching losses, and hybrid renewable energy sources. By utilizing the EJS algorithm, the proposed strategy has the potential to achieve superior outcomes based on cost savings, energy efficiency, and grid stability compared to conventional methods. Furthermore, the integration of this method contributes to the advancement of optimization algorithms and neural network applications.

Discontinuous PWM Technique With Reduced Low-Order Harmonic Distortion for High-Power Applications

The modulation techniques used in high power applications have to generate high quality waveforms with reduced switching losses. As an attractive alternative, Discontinuous PWM (DPWM) techniques present lower device switching frequencies than conventional continuous PWM methods lowering the converter switching loss. Considering the same cooling system, this allows to increase the carrier frequency of DPWM methods displacing the main switching harmonics to higher frequencies. As a main drawback, when low carrier to fundamental ratios are used, DPWM methods present some undesired low-order harmonics that are required to be filtered. This paper presents a low-order harmonic minimization method for synchronous DPWM methods by modifying the conventional modulating reference to limit low order harmonics amplitude, while keeping the same effective switching frequency and thus limited switching losses.

Optimization of switching losses of the Weinberg converter

DC-DC converters are widely used in hybrid power supply systems. A buffer source of electrical energy (most often a battery bank) and its charging and discharging devices are integral parts of such systems. In systems where the battery bank voltage is less than the DC-bus voltage and galvanic isolation is not required, the Weinberg converter is widely used as a discharge device, for example, in spacecraft power supply systems. The current trend in the development of hybrid power supply systems is to increase the power density of the system. Increasing the operating frequency is the simplest and most effective way to increase the power density of converter. A differential characteristic of this converter is the zero-current switching (ZCS) of transistors, which occurs due to the influence of the leakage inductance of coupled-inductors and the leakage inductance of the transformer. The paper presents an analysis of the influence of leakage inductances on the operation of the converter and a method of determining a level of turn on switching losses of transistors, which allows to ensure the necessary level of efficiency of the converter. The results of simulation modeling of the converter confirm the effectiveness of this method.

Design and Comparative Analysis of an Ultra-Highly Efficient, Compact Half-Bridge LLC Resonant GaN Converter for Low-Power Applications

For low-power applications, this paper presents the development and design of a compact and ultra-highly efficient half-bridge LLC resonant converter. By using Galium Nitride (GaN) devices and high-efficient magnetics, the efficiency and power density of resonant converters can be improved. Compared to Silicon MOSFETs, GaN high-electron-mobility transistors (GaN HEMT) have a lower output capacitance and gate charge, resulting in lower driving loss and shorter dead times. Consequently, the proposed LLC converter based on GaN devices has excellent performance characteristics such as ultra-high efficiency, low switching losses, compact size, high voltage endurance, high operating temperature and high operating frequency. Furthermore, the proposed resonant converter features soft switching properties that ensure that the switches and diodes on the primary side are always switched at zero voltage and current. By doing so, LLC resonant converter switching losses are significantly reduced by up to 3.1%, and an overall efficiency of 98.5% is achieved. The LLC resonant converter design with GaN HEMT has great advantages over Si MOSFET solution regarding efficiency, overall losses, switching loose and power factor correction. A 240 W, 240 V to 60 V half-bridge GaN HEMT LLC resonant converter is simulated with a switching frequency of 75 KHz, along with the comparative analysis of the Si metal oxide semiconductor field effect transistor (MOSFET) solution. Moreover, the design and analysis of highly efficient magnetics with a power factor of 0.99 at full load is presented. A 240-Watt single stage LED driver with power factor correction is also designed to verify and compare the performance of proposed LLC resonant converter.

Zero-Loss Switching in $LLC$ Resonant Converters Under Discontinuous Conduction Mode: Analysis and Design Methodology

Many thriving applications where isolation is required, such as LED drivers, traction and EV fast charging, implement <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converters, particularly when voltage regulation is not required or an additional conversion stage is in charge of it. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter can be operated under discontinuous conduction mode (DCM), due to its advantages such as unregulated and sensorless operation, fixed switching frequency and voltage gain, and zero-current switching (ZCS). However, ZCS results in EMI and switching losses in the primary converter, particularly for ≥1200-V devices. Alternatively, zero-loss switching (ZLS) can be accomplished by means of a proper design of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter, overcoming the drawbacks of ZCS. The focus of this paper is to perform an exhaustive research on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter under DCM-ZLS: discontinuous conduction mode with lossless switching in the primary and secondary sides. As a result of this analysis, a set of design boundaries are deduced for parameters such as the magnetizing inductance, the leakage inductance, and the gate resistance. A comprehensive, step-by-step design methodology is proposed and applied to a 18-kW, 200-kHz test bench. The designed parameters are implemented in the converter and several experiments are conducted, including a test at rated input voltage and rated power (600 V, 18 kW). The conduction states studied theoretically in the analysis of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter are identified in the experimental results, and the operation of the test bench under DCM-ZLS is verified.

Sliding mode control technique of step down converter using reaching law

&lt;p&gt;The robust reaching law based sliding mode control is used for chattering suppression, minimization of steady state error and reaching speed kept minimized. With fine tuning of parameters of robust reaching law, the sliding mode reaches the equilibrium point at the earliest. The stability of the proposed reaching law is analyzed. In one hand, they guarantee the system reach the sliding face rapidly and stay on it, in another way they decline the chattering effectively, even unmatched certainties and disturbances. Such that the system response can better realize the unification of rapidity. &lt;br /&gt;A proposed reaching law ia analyzed mathematically and applied to SMC DC-DC buck converter to lessen the chattering, because switching devices are existing in the model, it reduces effectively in the switching losses in the switching devices of the dc-dc converter. In turn effectiveness of the efficiency increases. MATLAB/Simulink results give significant decline of chattering and switching losses in the buck converter.&lt;/p&gt;

Fuzzy Based Interleaved Step-up Converter for Electric Vehicle

This work focuses on the fuzzy controller for the proposed three-phase interleaved Step-up converter (ISC). The fuzzy controller for the proposed ISC converters for electric vehicles has been discussed in detail. The proposed ISC direct current (DC-DC) converter could also be used in automobiles, satellites, industries, and propulsion. To enhance voltage gain, the proposed ISC Converter combines boost converter and interleaved converter (IC). This design also reduces the number of switches. As a result, ISC converter switching losses are reduced. The proposed ISC Converter topology can produce a 143 V output voltage and 1 kW of power. Due to the high voltage gain of this converter design, it is suitable for medium and high-power systems. The proposed ISC Converter topology is simulated in MATLAB/Simulink. The simulated output displays a high output voltage. But the output voltage contains maximum ripples. Fuzzy proposes an ISC Converter which makes closed loop responsiveness and reduces the output voltage ripple. The proposed ISC converter has the lowest ripple output voltage, which is less than 2%, because the duty cycle is regulated using the fuzzy logic controller. It offers high voltage gain, minimal ripple, and low switching loss. The performance of the proposed converter is compared to that of the fuzzy and Proportional Integral (PI) controllers implemented in MATLAB.

High Bandwidth Series-Form Switch-Linear Hybrid Envelope Tracking Power Supply With Reduced Bandwidth Envelope and Step-Wave Edge Adjustment Methods

The series-form switch-linear hybrid envelope tracking (ET) power supply is constituted by a multilevel converter and a linear amplifier connected in series, featuring high efficiency and wide tracking bandwidth. With the development of wireless communication, the envelope bandwidth of the radio-frequency signal reaches tens of megahertz and even hundreds of megahertz, leading to a high switching loss in the multilevel converter and thus degraded overall efficiency of the ET power supply. To reduce the switching loss and ensure high tracking bandwidth, this article proposes to let the multilevel converter track the reduced bandwidth envelope signal and the linear amplifier track the original one. Then, a step-wave edge adjustment method is proposed to adjust or eliminate the rising and falling edges of the step-wave voltage for further reducing the equivalent switching frequency of the multilevel converter and the voltage across the power device of the linear amplifier. As a result, the switching loss in the multilevel converter and the power loss in the linear amplifier could be reduced, leading to a notably higher overall efficiency. A prototype with 40 MHz tracking bandwidth, 7–27 V output voltage, and 15 W average output power is fabricated and tested in the lab, and the experimental results are provided to verify the effectiveness of the proposed method.

Investigation of ZVS Criteria and Optimization of Switching Loss in a Triple Active Bridge Converter Using Penta-Phase-Shift Modulation

Triple active bridge (TAB) as an isolated multiport dc–dc converter is a promising solution for integrated energy management systems to maintain an efficient power flow between the ports. This article presents the design, modeling, and switching loss optimized phase-duty-controlled PWM modulation scheme of a TAB converter composed of three full-bridge modules and a high-frequency planar transformer. The work aims at the derivation and analysis of the zero-voltage switching (ZVS) conditions for a TAB, where the turn-on switching loss is mitigated along with attaining an improved EMI performance, comprising of reduced noise peaks. Moreover, an optimized five-variable control-based TAB PWM modulation technique is proposed in this article in order to achieve minimized switching loss and the overall system loss for a wide voltage gain and load range. The instantaneous switching currents, responsible for the switching losses at the devices, are derived from the transformer winding current expressions, formulated employing the generalized harmonic approximation (GHA) technique. The various loss minimization techniques and the theoretically obtained criteria for ZVS are experimentally verified using a laboratory-developed prototype of an 800-W TAB converter. With the implementation of the proposed optimal phase-duty control, the experimental results show a nonunity gain light-load efficiency increment up to 10% compared to the conventional phase-shift modulation alone.

A High Voltage Gain Multi-Stage DC-DC Boost Converter with Reduced Voltage Stress

Future transportation will replace the current mechanical combustible engines with chargeable electric vehicles (EVs). The DC-Dc boost converter is an essential part of such systems that not only helps to generate the required level but also helps to regulate the load voltage. In conventional boost converter topologies, their gain, switching losses, and high voltage stress across switches are the main reason for limiting the output power. Coupled inductor-based isolated converters increase the system weight and cost. Therefore, in this paper, a transformerless adjustable gain and non-isolated DC-DC boost converter with multi-port flexible power supply, reduced switch voltage stress, and considerable good range efficiency is proposed. The proposed converter is tested with the 100 W resistive load to test the desired characteristics.

Simplified Gate Driver Design Technique for Multi-MHz Switching GaN FETs in Three-Level Buck-Based 4G/5G Envelope Tracking

Multi-MHz switching frequency converter-based envelope tracking dc power supplies are widely adopted in modern 4G/5G communication base stations to improve the efficiency of radio frequency power transmitters. The switching loss of buck converter at MHz switching frequency increases with the input dc voltage. To obtain higher output voltage range without much compromise on the efficiency, multilevel converters with discrete low voltage gallium nitride (GaN) field-effect transistors (FETs), switching at multi-MHz frequency, are used. However, the gate driving circuit and PCB layout of a multilevel buck converter are complex and occupy major portion of the board when compared with the power GaN FETs. This article proposes a simplified gate driving technique in a cascaded bootstrapping architecture for a three-level buck converter with reduced number of components that can support up to 40 MHz switching frequency. The converter can reproduce any reference envelope signal with a maximum bandwidth of 8 MHz and output voltage variation from 6 to 42 V. Hardware prototype is developed, and experimental results are presented to validate the concept.

Variable DC Voltage Shipboard Power System With Permanent Magnet Generator and Diode Front End

The application of dc power systems to microgrids, such as the power system for vessels and islands, is gradually increasing. The major advantage of the dc system over the conventional ac system is the reduced fuel consumption and emission, which is mostly due to the variable speed operation of the diesel engine. It has been reported that the efficiency of the dc system can be maximized if the generation unit comprises a permanent magnet generator (PMG) and a diode rectifier. However, the fatal disadvantage of this composition is that the optimal efficiency operation of the variable speed engine may not be always possible unless the parameter of the PMG, specifically per-unit stator inductance, is within a specific range. The dc system design method proposed herein allows for a large voltage variation (e.g., 40%), and it is possible to operate engine along its optimum efficiency operating point even if the generator per-unit stator inductance does not have a specific range. At light-load conditions, in particular, the proposed method can reduce power converter switching loss and diesel engine fuel consumption. The validity of the proposed method was verified using computer simulations and small-scale experiments.

Five-Level Hybrid Active-NPC H-Bridge Converter With Novel Space-Vector-Modulation Scheme

This article presents a five-level hybrid active-neutral-point-clamped H-bridge (HANPC H-bridge) converter topology for a single-phase system. The proposed HANPC H-bridge topology utilizes a combination of silicon (Si) and silicon carbide (SiC) switches to enable high switching frequency operation. Furthermore, a novel space-vector-modulation (SVM) scheme is proposed to switch the two legs of the proposed converter at different switching frequencies. For this, a generalized approach to control relative difference in the switching frequencies of the two converter legs based on converter switching losses is proposed. Using the proposed modulation scheme, HANPC H-bridge converter features reduced switching losses, improved harmonic performance of output voltage and current, and optimal device utilization to achieve low cost at high efficiency. Moreover, a closed-loop control to balance the dc-link capacitors is presented, which provides the capacitor voltage balancing even under dynamic loading conditions without affecting its output voltage. The performance of the proposed converter is analyzed using the analytical and simulation results. Finally, experimental results are presented using the scaled-down prototype to validate the operating principles and performance of HANPC H-bridge converter using the proposed SVM scheme and capacitor voltage balancing control.

Control Strategy for Single-Phase Grid-Interfaced Modified Multilevel Inverter Topology for Distributed Power Generation

In this article, a multiresonant proportional-resonant (PR) controller-based current controller is presented for a single-phase multilevel inverter topology, enabling grid-current injection into the distribution grid at unity power factor. The multiresonant PR-controller compensates third and fifth harmonic components to improve the harmonic spectrum of the grid injected current. Moreover, to reduce the switching losses in the power electronics converter, the nearest level modulation technique has been adopted, increasing overall efficiency. Furthermore, a modified multilevel inverter has been presented for grid integration, which requires a reduced number of switching components and isolated dc sources. In addition, system stability and sensitivity analysis are presented to evaluate the performance of the controller. The proposed scheme reduces the harmonic content in the grid current and the steady-state error in the grid injected power. Furthermore, the multiresonant PR-controller and PI-controller performance is verified in terms of steady-state error and total harmonic distortion in the grid current. An experimental prototype of the 21-level modified multilevel inverter-based grid-connected system has been developed to validate the claim.

Fundamental switched MW‐size multilevel converter for large‐scale solar PV plant

The requirement of high power (MW-size) power conditioning unit (PCU) has increased to minimise the plant balance of system cost due to a continuous increase in solar photovoltaic (PV) plant capacity. Traditionally used high-frequency pulse-width modulated two/three-level PCUs have high device switching losses and lower conversion efficiency and are not suitable for high power PCU application as high switching losses lead to high heat generation within the converter, which is very difficult to manage, and lower conversion efficiency leads to less revenue realisation. In the present work, fundamental switching selective harmonic elimination (SHE) modulated 11-level cascaded H-bridge voltage source converter is utilised for high power MW-size PCU application, as it has lower switching losses, higher conversion efficiency, and higher AC/DC voltage ratio. The PV plant configuration for a 40 MW (AC) capacity is developed in the MATLAB/Simulink environment and implemented in real-time simulator OPAL-RT to validate the design and control. Harmonics, steady-state, and dynamic performances are demonstrated at constant and changing solar irradiance levels. The converter conduction and switching losses and conversion efficiency at different loading conditions are presented. The converter control with the capacitor voltage balancing method for fundamental switched SHE is presented in detail.

Simple discontinuous PWM strategies to reduce the switching losses of an indirect matrix converter

This work proposes the new discontinuous pulse width modulation (DPWM) schemes for an indirect matrix converter (IMC) to reduce the switching losses. The use of discontinuous modulation signals reduces the switching losses of the IMC by reducing the switching counts per cycle of the output converter. The key feature of the proposed schemes is the easy implementation as compared to existing DPWM schemes of the IMC. The major drawback of the existing DPWM schemes is the absence of zero current commutation (ZCC). In the absence of ZCC, the switchings of the input converter are accomplished through four-step commutation which adds the difficulties to the implementation. The proposed scheme overcomes above limitation by using the triangular carrier instead of the sawtooth carrier for the modulation of input converter. Consequently, the ZCC is enabled on the input converter which allows the use of two-step commutation. The two-step commutation simplifies the implementation to a great extent. The presented scheme provides the required input/output performance similar to continuous PWM (CPWM) schemes. The proposed work is verified by the simulation and experimental results. The reduction in the switching losses of the IMC by the new scheme is verified based on the comparison with the CPWM scheme.

Enhanced sliding mode controller performance in DC-DC buck converter using a tan hyperbolic reaching law and constant plus proportional reaching law

This paper presents an enhanced sliding mode controller (SMC) operation, chattering analysis and loading conditions of the SMC DC-DC buck converter. Sliding mode portion, chattering attenuation are analyzed by using a conventional and proposed reaching law in buck converter. A proposed tan hyperbolic reaching law (THRL) is originated to be useful in terms of chattering mitigation and fast convergence. The major drawback of the conventional reaching law viz, it bypasses the main portion of the sliding mode portion to ensure fast reaching. It causes more chattering, more time to reach the steady state on the switching surface. The most significant improvement of SMC is that it guarantees strengthening the sliding mode phase. The proposed tan hyperbolic reaching law is being hit here during an exponential adjustment so that the attributes of it, covers complete sliding mode portion, chattering mitigation and fast reaching time. In turn, cause fewer switching loss in the buck converter. Even external disturbances and uncertainty of the system occurs. The loading conditions are applied to proposed tan hyperbolic reaching law and analyzed. Simulation analysis conducted by MATLAB/Simulink.

Predictive Control Method Based on Adjacent Vector Confinement Technique for a Three-Phase AC-DC Matrix Converter with High Efficiency

A model predictive current control method is proposed to reduce switching losses in an AC-DC matrix converter. In the proposed control strategy, several vectors are selected from among all possible switching vectors for a given location of the input current reference. The switching vector that minimizes the cost function is applied to the converter in the next sampling period. The principle of the proposed method involves clamping the selected switches to stop performing the switching operation to minimize the number of switchings in every sampling cycle. The total efficiency of the AC-DC matrix converter under the proposed strategy is 91.2% whereas that of the conventional strategy is 89.7%. In addition, unity-power-factor operation is guaranteed and smooth and sinusoidal waveforms are achieved. Finally, simulation and experimental results are demonstrated to confirm the validity of the proposed control strategy.

Optimal Dead-Time Control Scheme for Extended ZVS Range and Burst-Mode Operation of Phase-Shift Full-Bridge (PSFB) Converter at Very Light Load

Phase-shift full-bridge (PSFB) converter is a widely used topology for high-efficiency and high-power applications, thanks to low voltage/current stress of all components and zero-voltage-switching operation of primary mosfet s. The critical drawback of the PSFB converter is hard-switching characteristics of primary mosfet s at a very light load, which causes severe thermal explosion and extremely high input power consumption, especially with the latest super-junction mosfet . To minimize the switching loss of the PSFB converter at a very light load, a new optimal dead-time control scheme with burst-mode operation is proposed in this paper and its validity is verified experimentally with the implemented 2.2-kW server power supply unit.

Optimization of Switching Loss of a DC-DC Boost Converter

The dc-dc boost converters are widely used in various power conversion applications because of their increase in demand both in domestic, commercial and industrial applications. The voltage boosting techniques include mostly combination of components such as inductors, capacitors, switches etc with their various configurations. The combination of these boosting components oriented in different configurations appears largely in literature, but refer the techniques of hard-switching of the semi-conductor devices. In order to meet the growing demand and to look into the aspect of better efficiency of these converters, the soft-switching of devices plays a prominent role, which lacks in literature. Though very few papers appear in literature as far as soft-switching is concerned, but the addition of more than one or two switches make the things uneasy and the researchers lack interest in it. Even though the conventional boost converters appear in various forms of topologies in literature, but it needs further critical investigation so far to minimise switching loss. The proposed topology, which is similar to the conventional topology with slight modification, gives lucid insight in fulfilling with partial soft-switching capability of circuits. The single switch is turned-off under zero-voltage switching (ZVS) and turned-on under partial hard-switched by proper designing of snubber components. The prominent components of the topology are designed at its optimum level to improve performance.