Converter Circuit Model Research Articles

Event‐triggered finite‐time H∞ output tracking control of switched systems with round‐robin protocol and its applications

AbstractIn this article, the finite‐time H∞ output tracking control problem is addressed for the networked switched systems. A hybrid event‐triggered scheme is introduced to reduce the network transmission overload. A round‐robin communication protocol is structured to determine the access rights of the sensor and alleviate the bandwidth pressure as well. Sufficient criteria for finite‐time stability of the closed‐loop systems with asynchronous switching characteristics are derived by resorting to a double‐mode dependent Lyapunov–Krasovskii functional. Finally, an application example of the buck‐boost converter circuit model is demonstrated to illustrate the effectiveness of the developed methods.

A novel modelling and control strategy for a full-wave ZCS quasi-resonant boost converter for a PV-based battery charging system

In this paper, a novel modelling and control strategy is proposed for a DC-DC quasi-resonant boost converter utilised in a photovoltaic-based (PV-based) battery charging system. The MOSFET switch of the boost converter is operated at zero current using a resonant tank, providing soft-switching functionality, to reduce the switching losses experienced by conventional boost converters. The principles of operation of the utilised converter are analysed in detail and a characteristic function representing the model of quasi-resonant converter circuit is derived. This model is then used to design and implement a frequency control technique, which will maintain a constant DC voltage at the output stage of the converter to charge the battery. Simulation studies are conducted using MATLAB Simscape toolbox to evaluate the performance of the proposed controller. Simulation results validate the soft-switching functionality of the converter and its ability to reach and maintain the desired output voltage for charging a battery load in the presence of varying input voltage generated by a PV system with intermittent nature.

A novel modelling and control strategy for a full-wave ZCS quasi-resonant boost converter for a PV-based battery charging system

In this paper, a novel modelling and control strategy is proposed for a DC-DC quasi-resonant boost converter utilised in a photovoltaic-based (PV-based) battery charging system. The MOSFET switch of the boost converter is operated at zero current using a resonant tank, providing soft-switching functionality, to reduce the switching losses experienced by conventional boost converters. The principles of operation of the utilised converter are analysed in detail and a characteristic function representing the model of quasi-resonant converter circuit is derived. This model is then used to design and implement a frequency control technique, which will maintain a constant DC voltage at the output stage of the converter to charge the battery. Simulation studies are conducted using MATLAB Simscape toolbox to evaluate the performance of the proposed controller. Simulation results validate the soft-switching functionality of the converter and its ability to reach and maintain the desired output voltage for charging a battery load in the presence of varying input voltage generated by a PV system with intermittent nature.

Adaptive Event-Triggered SMC for Stochastic Switching Systems With Semi-Markov Process and Application to Boost Converter Circuit Model

In this article, the sliding mode control (SMC) design is studied for a class of stochastic switching systems subject to semi-Markov process via an adaptive event-triggered mechanism. Network-induced communication constraints, semi-Markov switching parameters, and uncertain parameters are considered in a unified framework for the SMC design. Due to the constraint of measuring transducers, the system states always appear with unmeasurable characteristic. Compared with the traditional event-triggered mechanism, the adaptive event-triggered mechanism can effectively reduce the number of triggering than the static event-triggered mechanism. During the data transmission of network communication systems, network-induced delays are characterized from the event trigger to the zero-order holder. The aim of this work is to design an appropriate SMC law based on an adaptive event-triggered communication scheme such that the resulting closed-loop system could realize stochastic stability and reduce communication burden. By introducing the stochastic semi-Markov Lyapunov functional, sojourn-time-dependent sufficient conditions are established for stochastic stability. Then, a suitable SMC law is designed such that the system state can be driven onto the specified sliding surface in a finite-time region. Finally, the simulation study on boost converter circuit model (BCCM) illustrates the effectiveness of the theoretical findings.

Modeling and simulation of constant current converter in energy branch unit

As an important part of electric energy branch unit, constant current converter has the characteristics of simple structure and high efficiency. In this paper, a constant-current converter used in underwater power branching unit is modeled and simulated. The model of constant-current converter circuit is established by using state space method, and the steady-state operating point of DC is calculated. Based on the model, maximum impulse current and drain-source voltage of switching transistor in constant current converter are studied. The simulation test of constant-current converter is carried out by Saber simulation software. The results show that the circuit efficiency can be maintained above 90% while the reliability of the converter is guaranteed, which provides a theoretical basis for the analysis and research of efficient and reliable underwater power branch units.

Weighting Factor Design in Model Predictive Control of Power Electronic Converters: An Artificial Neural Network Approach

This paper proposes the use of an artificial neural network (ANN) for solving one of the ongoing research challenges in finite set-model predictive control (FS-MPC) of power electronics converters, i.e., the automated selection of weighting factors in cost function. The first step in this approach is to simulate a detailed converter circuit model or run experiments numerous times using different weighting factor combinations. The key performance metrics [e.g., average switching frequency ( $f_{{\rm sw}}$ ) of the converter, total harmonic distortion, etc.] are extracted from each simulation. This data is then used to train the ANN, which serves as a surrogate model of the converter that can provide fast and accurate estimates of the performance metrics for any weighting factor combination. Consequently, any arbitrary user-defined fitness function that combines the output metrics can be defined and the weighting factor combinations that optimize the given function can be explicitly found. The proposed methodology was verified on a practical weighting factor design problem in FS-MPC regulated voltage source converter for uninterruptible power supply system. Designed weighting factors for two exemplary fitness functions turned out to be robust to load variations and to yield close to expected performance when applied both to detailed simulation model (less than 3% error) and to experimental test bed (less than 10% error).

Optimal Design of High-Power Modular Multilevel Active Front-End Converter Using an Innovative Analytical Model

Optimal design and selection of arm inductances have been as a challenging subject in the field of modular multilevel converter (MMC). The average steady-state model is generally used as the analytical circuit model that neglects the switching frequency and harmonic values. Also, most of the researchers neglect the saturation effect of inductor core to simplify the analytical model. Contrary to the transformers, choosing the maximum flux density of inductance core is a sensitive issue, in order to design and minimize the inductors. Increasing the flux density reduces the inductor size, but getting close to the saturation region might alter the performance of the converter. This paper presents a systematic optimization approach to minimize high-power MMCs with saturable arm inductance considering technical, thermal, and manufacturing constraints. An accurate steady-state analytical model of MMC converter has been proposed and verified. A combination of converter circuit model and inductance electromagnetic model is employed to find the optimal arm inductances and capacitor values. The effect of nonideal inductance core on converter outputs has been investigated. A dimensioning model of inductor consisting of electromagnetic and thermal models is presented. To compute the optimal inductor size, a novel hybrid optimization loop is proposed including the analytical model of the converter and the inductor in which circuit, electromagnetic, and thermal properties are taken into consideration. In order to increase the accuracy of the dimensioning model, an internal verification loop is employed to verify and correct the analytical model using finite-element analysis. The proposed optimization loop aims to find the minimum inductor size considering technical and manufacturing constraints. Finally, the converter mass sensitivity of MMC converter versus some important constraints, such as temperature rise and capacitor ripple, has been investigated.

Simulation and Analysis of Multiphase Boost Converter with Soft-Switching for Renewable Energy Application

<span>This paper presents the simulation design of dc/dc interleaved boost converter with zero-voltage switching (ZVS). By employin the interleaved structure, the input current stresses to switching devices were reduced and this signified to a switching conduction loss reduction. All the parameters had been calculated theoretically. The proposed converter circuit was simulated by using MATLAB/Simulink and PSpice software programmes. The converter circuit model, with specifications of output power of 200 W, input voltage range from 10~60 V, and operates at 100 kHz switching frequency was simulated to validate the designed parameters. The results showed that the main switches of the model converter circuit achieved ZVS conditions during the interleaving operation. Consequently, the switching losses in the main switching devices were reduced. Thus, the proposed converter circuit model offers advantages of input current stress and switching loss reductions. Hence, based on the designed parameters and results, the converter model can be extended for hardware implementation.</span>

Design for boost DC-DC converter controller based on state-space average method

abstractThe accurate mathematical model of converter is very important in the process of designing high performance switch power. Nonlinear, multimodal and time-varying are the characteristics of the DC-DC converter. So it is necessary to study it in a new way. This paper presents a mathematical model of Boost converter circuit by state space average method. The closed-loop PI controller based on the Boost converter model was designed. The static and dynamic performance of the closed-loop system was tested in Simulink which demonstrated a good behavior of the system to meet the requirements of user.

Design for Boost DC-DC Converter Controller Based on State-Space Average Method

In the process of designing high performance switch power, need to establish the accurate mathematical model of converter. The DC/DC converter generally has the characteristics of nonlinear, multimodal, time-varying, so need to use new methods to study it. The work of this paper aimed at non isolated DC / DC converter, established the mathematical model of Boost converter circuit by using the state space average method. Then design the closed-loop PI controller based on the Boost converter model, the closed-loop system has good static and dynamic performance, to meet the requirements of use.

Design of Driving Circuit of GDI Injector and Experiment Verification

In order to precisely control the injection responsivity of the Gasoline Direct Injection（GDI）engine，a higher requirement of the injector drive circuit should be achieved[5]. This paper introduces a new design of driving circuit for the injector of the EA888 engine. the thesis creates a simulation model of BOOST converter circuit using multisim simulation tool, Simulation results show that voltage ripple is less than 10%.The characteristics of GDI injector are measured and analyzed , the feasibility of the driving circuit is verified.

A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters.

A Robust Approach to Controller Design for DC-DC Quasi-Resonant Converters

DC-DC quasi-resonant converters (QRCs) have a highly nonlinear and time-varying behavior as well as other types of DC-DC resonant converters such as conventional and multi-resonant converters. Changing in operating conditions, mainly due to variation in load and line disturbance, leads to significant changes on system dynamics so that desired performance and even stability are lost. Taking into consideration the uprising need for high-quality resonant power converters has opened a new research window on the control of these systems using modern and systematic approaches.In this paper in order to achieve both stability and desired performance, such as reduced sensitivity to load variations, desired disturbance rejection, reduced output impedance and attenuated transfer from input to output, we have proposed a methodology based on μ-synthesis technique for DC-DC QRCs controller design. The μ-analysis is used to verify the robustness of the designed controller. The proposed control strategy is applied to a typical zero-current switching QRC and nonlinear simulation is performed using nonlinear model of converter circuit. The simulation results demonstrate the good reference voltage tracking, line disturbance rejection and show that the designed procedure guarantees the robust stability and robust performance for a wide range of load variation.