Dual Heuristic Dynamic Programing Control of Grid-Connected Synchronverters

A new approach to control a grid-connected synchronverter by using a dual heuristic dynamic programing (DHP) design is presented. The disadvantages of conventional synchronverter controller such as the challenges to cope with nonlinearity, uncertainties, and non-inductive grids are discussed. To deal with the aforementioned challenges a neural network–based adaptive critic design is introduced to optimize the associated cost function. The characteristic of the neural networks facilitates the performance under uncertainties and unknown parameters (e.g. different power angles). The proposed DHP design includes three neural networks: system NN, action NN, and critic NN. The simulation results compare the performance of the proposed DHP with a traditional PI-based design and with a neural network predictive controller. It is shown a well-trained DHP design performs in a trajectory, which is more optimal compared to the other two controllers

EMC Improvement for High Voltage Pulse Transformers by Pareto-Optimal Design of a Geometry Structure based on Parasitic Analysis and EMIPropagation

High voltage pulse transformers have an essential role in pulsed power systems and power conversion applications. Improving the electromagnetic behavior of such devices leads to better efficiency and low-level electromagnetic interference (EMI) noise propagation in systems. In this paper, a high voltage pulsed power system is considered and analyzed to improve their electromagnetic compatibility (EMC). The new generation of pulsed power systems that use SiC and GaN fast switches in capacitor charger power electronic circuits, face far more EMI challenges. Moreover, in this paper, the EMI propagation paths in the pulsed power system are realized and analyzed. The EMI noise level of the system is obtained and compared to the IEC61800-3 standard. To improve the EMC, the parasitic parameters of the transformer, as the main path of EMI circulation, are optimized to block the EMI propagation in the pulsed power system. To achieve this result, the parasitics are modeled and calculated with a novel and accurate energy distribution model. Then, by defining a cost function, the geometry structure of the transformer is optimized to lower the parasitics in the system. Three pareto-optimal techniques are investigated for the cost function optimization. The models and results are verified by the 3D-finite element method (FEM) and experimental results for several given scenarios. FEM and experimental verifications of this model, make the model suitable for any desirable design in any pulsed power system. Finally, the EMI noise level of the system after optimization is shown and compared to the IEC61800-3 standard

Investigation of Various Transformer Topologies for HF Isolation Applications

High-frequency (HF) transformers are an essential part of many power electronic devices. The performance and behavior of HF transformers can greatly affect the efficiency and performance of all systems, particularly, from a parasitic parameter point of view. In this article, HF transformers\u27 parasitic parameters, such as leakage inductances and parasitic capacitances, are analyzed using a novel analytical method, finite element method (FEM), and experimental measurements of different structures and winding arrangements. Also, the magnetic field, electric field, electric displacement field, and electric potential distribution within the transformers are simulated and analyzed. Four different HF transformers with E and U cores with different windings are designed and analyzed. Investigation outcomes help to classify structures according to the trade-off between leakage inductances and series parasitic capacitances. This information can later be used for the optimal selection and design of transformers as a function of their operating frequency for any power rating and voltage level. Moreover, 3-D FEM and experimental results validate the proposed methodology to be used for designing HF transformers in high-voltage/power applications

EMC Modeling and Conducted EMI Analysis for a Pulsed Power Generator System Including an AC-DC-DC Power Supply

High-voltage (HV) pulsed power generators are very important in plasma generation in corona discharge reactors. With the advent of new fast switches technologies such as silicon carbide (SiC) and gallium nitride (GaN), electromagnetic interference (EMI) noise in such systems are very challenging. In this article, electromagnetic compatibility (EMC) modeling and conducted EMI analysis for a pulse generator including an ac-dc-dc power supply are developed. Moreover, the common mode (CM) EMI noise propagation through the system is discussed and the noise sources and effect of each component on the noise flowing are analyzed. The ac-dc-dc power supply role is also investigated and since there is an isolation stage in the system, the effect of high-frequency (HF) transformers that provide a flowing path for noise is also studied. In addition, the CM impedance of different parts of the system as well as the noise voltage are discussed by regarding different values for parasitic parameters of the system. As the system noise level could not meet IEC61800-3 standard, EMI attenuation techniques were applied to the system. By using balance technique and adding filtering inductor as a decoupling inductance, the EMI noise is reduced. Furthermore, an EMI filter optimized and designed for the power supply system that could reduce the EMI noise level. However, by using some EMI reduction techniques that are explained in this article, the size of the required EMI filter is reduced. In this article, EMC modeling, conducted EMI analysis, and EMI reduction techniques led to higher performance and efficiency and lower size of EMI filter that reduced the overall size of the system

A New Topology of a High-Voltage-Gain DC-DC Converter based on Modified Greinacher Voltage Multiplier

This paper proposes a new topology of a non-isolated two-phase interleaved boost dc-dc converters with modified Greinacher voltage multiplier cells (VMCs) in continuous conduction mode (CCM). The proposed topology can quickly achieve a high gain with low stress on components and proper duty cycle. Moreover, this topology requires a small inductance size in CCM while maintaining the continuity of the input current due to the interleaved technique used in this converter. Because of these features, this topology can be used in many renewable applications such as PV, DC microgrids, etc. The design procedures and component selection are presented in this paper. Furthermore, the proposed converter was simulated to convert an input voltage of 20 V to output voltage of 400 V with an output power of 200 W. Finally, experimental results have been provided to confirm the analysis and simulation results

An Interleaved Non-Isolated DC-DC Boost Converter with Voltage Doubler Cell in CCM

This paper introduces an interleaved non-isolated of a boost converter with voltage doubler cell in continuous conduction mode (CCM), which can be used in many renewable energy applications, such as photovoltaic (PV) and fuel cells. The proposed converter consists of two stages. The first stage is a two-phase interleaved boost stage, and the second stage is voltage doubler voltage multiplier. Due to these two stages, the proposed converter produces twice the voltage gain of the conventional boost converter while maintaining the continuity of the input current and with lower stresses on components. The analysis and design procedure of the proposed converter is discussed in this paper. Also, a simulation tool is used to verify the steady-state analysis of the converter. Finally, a hardware prototype was executed in the laboratory to convert 15 to 200 Vdc to confirm the theoretical analysis and simulation results

A new Topology of a High-Voltage-Gain DC-DC Converter Based on Modified Greinacher Voltage Multiplier

This paper proposes a new topology of a non-isolated two-phase interleaved boost DC-DC converters with modified Greinacher voltage multiplier cells (VMCs) in continuous conduction mode (CCM). The proposed topology can quickly achieve a high gain with low stress on components and proper duty cycle. Moreover, this topology requires a small inductance size in CCM while maintaining the continuity of the input current due to the interleaved technique used in this converter. Because of these features, this topology can be used in many renewable applications such as PV, DC microgrids, etc. The design procedures and component selection are presented in this paper. Furthermore, the proposed converter was simulated to convert an input voltage of 20 V to output voltage of 400 V with an output power of 200 W. Finally, experimental results have been provided to confirm the analysis and simulation results.Comment: withdraw due to technical error

Analysis and Modeling of a Non-Isolated Two-Phase Interleaved Boost Converter with Diode-Capacitor Cells in the DCM

In this paper, a two-phase interleaved dc-dc boost converter with two cells of diode-capacitor is analyzed and investigated in discontinuous conduction mode (DCM). Furthermore, mathematical modeling with a component selection procedure is discussed in this study. The mentioned converter is used to convert 10 V to 202.08 Vdc, which can be used in many renewable energy applications, such as photovoltaic (PV) and fuel cells. To verify the mathematical analysis and the simulation, a hardware prototype was built and implemented in a laboratory. Also, the experimental results have been compared with the proposed simulated model. The final results show consensus between mathematical expressions, simulated results, and measured results, which verifies the effectiveness of this proposed converter in the DCM