POWER ELECTRONICS [IEEE-2019] PROJECTS

Abstract:- The existing chargers for electric vehicle use rugged nonlinear diode bridge rectifier to avail DC voltage at the input of DC-DC converter, and introduce serious power quality issues in the input AC current. These issues set the formidable need to improve the power quality (PQ) performance of existing battery chargers by eliminating the input bridge. This is achieved in the proposed work, by the addition of an improved PQ based bridgeless (BL) Luo converter. The proposed PFC converter is the combination of two Luo converters, which operate independently in the respective half cycles, with common input inductor. The converter provides low cost and high power density based EV charging solution as fewer number of components conduct over single switching cycle due to elimination of input diode bridge in conventional PFC converter. The charger input current is made to follow the source voltage, exactly in phase and high input power factor is achieved. Moreover, source current THD is reduced below 5% as per the IEC 61000-3-2 standard under steady state and during sudden variation in source rms voltage.

Keywords:- Power Quality, Battery Charger, Electric Vehicle, Luo Converter, IEC 61000-3-2 standard.

Abstract:- The article describes the method of detection of stator short circuit faults in three-phase asynchronous motor, which is based on coordinate transformation of current vector. According to statistics, 78% of the stator faults are an inter-turn short circuit, which happens due to the turn insulation destruction. In many cases, it leads to motor shutdown. The principles of diagnostic system development of the stator windings via current measurements are shown. The efficiency of proposed algorithms for stator short circuit faults detection was confirmed by the simulation results. Also motor with inter–turn short circuit was tested with help of laboratory test-bench.

Keywords:- induction motor; stator inter-turn short circuit; current vector; coordinate transformation; laboratory test-bench.

Abstract:- Latterly, impedance source based multilevel inverters are becoming popular for emerging renewable power generations. This paper presents a Five-Level quasi Z-source (qZS) based neutral point clamped (NPC) for photovoltaic (PV) applications. This inverter circuit is formed by integrating a dual quasi Z-source with a T-type arm and a diode clamped arm. Compared to the existing impedance source based NPC type converters, the proposed topology has less number of switching devices and reduced voltage stress. The level shifted pulse width modulation (LS-PWM) with hybrid shoot-through technique is implemented to achieve high boost gain and reactive power capability. The performance of the proposed topology is examined through simulation results for input voltage changes and load changes.

Keywords:- Quasi Z-source, Five-Level Inverter, Neutral Point Clamped, Level Shifted PWM.

Abstract:- A novel fuzzy logic (FL) control scheme to regulate the speed of a permanent magnet (pm) dc motor drive via armature voltage control, has been developed. The pmdc motor drive is fed from a $phase thyristor controlled rectifier. The proposed FL rule based controller scheme utilizes both motor current and speed errors. The firing delay angle (a) of the 3-phase converter is determined as the output of a modified "weighted centre of area"(WCOA) defuzzifier stage, with an assigned rule base. The controller utilizes novel on-line adjustable defuzzification- weighting criteria to ensure minimum speed overshoot/undershoot as well as reduced motor transient inrush current conditions. The on-lane tuning criteria is based on the speed error excursion level.

Keywords:- Fuzzy Logic; Defuzzification; Thyristor.

Abstract:- This paper presented a d-q model of a three-phase induction motor with two stator phases open-circuit (faulty three- phase induction motor). It is shown that with an appropriate transformation, the d-q model of faulty motor has the same structure of equation as a balanced three-phase induction motor. Based on the developed model of the faulty induction motor, simulations are carried out to study on the dynamic behavior of the faulty three-phase induction motor. The developed model for faulty 3-phase induction motor can be extremely useful in designing a controller for fault-tolerant drive system.

Keywords:- faulty three-phase induction motor; d-q model; dynamic behavior; simulation results.

Abstract:- To fulfill the principle of low-cost and easy operation features, a new control scheme is proposed for the LARM Hand in this paper. The new controller is composed of a high level PC-based control panel and a low level DSP control card and the two parts communicate with each other through RS-232. The PC-based control panel is software with which an operator can input control parameters, and additionally the operator can observe the changes of the force values and velocities of three motors in real time. The DSP controller is mainly used to control the motion of three motors by PWM signals as based on position control and force control. A position control method based on PID controller and a force control method based on PD controller both have been proposed in this paper. Simulations based on a simplified model are also carried out for these two methods.

Keywords:- DSP Controller, Position Control, Force Control, LARM Hand.

Abstract:- This paper presents a robust control scheme for the Two–In-Wheeled Self–Balancing Electric Vehicle (TIW-SB-EV). The presence of unknown, time varying, and load-torque inputs, unknown system parameters, and the lack of knowledge of the dynamic and static frictions, suggests the design of a disturbance observer together with an active disturbance rejection control. This control scheme is known as Active Disturbance Rejection Control (ADRC) and in this work is synthesized via the differential flatness property of the system. For that, the system’s flat output is measured by means of an inclinometer. The power train for the TIW-SB-EV is constituted of two In-wheel brush-less DC motors (SG/F10-48V, 800W), which are fed by a controlled three-phase inverter. The EV power supply source is provided by two Lithium Ion batteries (48V, 10AH). The proposed ADRC algorithm is implemented on the TMS320F28335 digital signal processor (DSP) chip. Real-time experimental results validate the mechanical, electrical and control design and highlight the closed-loop robustness towards endogenous and exogenous disturbance.

Keywords:- Two–In-Wheeled Self–Balancing Electric Vehicle, Active Disturbance Rejection Control, Linear Extended State Observer.

Abstract:- This paper presents a resonant, capacitively isolated single-ended primary-inductor converter (SEPIC) suitable for high frequency power conversion operating at 10 MHz. Instead of an extensive manual parameter sweeping, parametric loss models are used to perform a Pareto optimization of the converter design. It is shown that this design approach is highly beneficial. The converters high efficiency of 90 % and its wide voltage range sets it apart from similar designs. It achieves voltage conversion ratios from zero (buck) to eight (boost) and throughout most of this range the converter can maintain soft switching conditions. The concept demonstrates that at such high frequencies a galvanic isolation can simply be implemented with capacitors instead of a transformer. Within the analysis, two circuit board prototypes with different technologies, FR4 and insulated metal substrate, are compared with respect to their electrical and thermal performance.

Keywords:- SEPIC, zero voltage switching, high frequency power conversion, Pareto optimization, DC-DC converter, wide band gap semiconductors.

Abstract:- A new high gain SEPIC-based converter is presented in this paper. The introduced topology provides many benefits, namely very high step-up voltage gain, positive output voltage, high efficiency, and easy control method. Additionally, due to the fact that the proposed SEPIC converter is transformer less, there is no voltage spike on the switches when they turn off. Furthermore, inasmuch as the input current of the presented topology is continuous, it can be employed in renewable energy applications. The operating principle and steady-state analysis of the introduced converter are investigated. Finally, the performance of the introduced converter as well as theoretical analysis is confirmed with the help of simulation and experimental results.

Keywords:- SEPIC-based converter; transformerless converter; high step-up voltage.

Abstract:- Power Distribution Unit (PDU) is a power supply unit that supplies various DC voltage levels for electric equipment. Reliability of PDU is very important in electrical systems. Buck converter is frequently used in PDU to provide the lower voltage levels than the source voltage level. The output capacitor of the buck converter is the main factor of failure. In this paper, we present a method to design a buck converter with almost no inductor current ripple. If the inductor current ripple is eliminated, the output capacitor can be removed from the converter. By removing the capacitor, the reliability and transient response of the converter can be improved considerably. The proposed method is based on interleaved buck converters. One of the advantages of interleaved converters is the low inductor current ripple. Theoretical analysis and simulation results are presented to justify the proposed idea.

Keywords:- current ripple, interleaved converters, reliability.

Abstract:- This paper introduces a high gain Single-Stage Boosting Inverter (SSBI). The proposed topology can be used for alternative energy generation and particularly in photovoltaic applications. As compared to the traditional two stage approach, SSBI has a simple topology, low decoupling capacitor and low component count. SSBI employs One Cycle Controller to generate its AC output and attain DC-AC power decoupling. The paper presents theoretical analysis, simulation and experimental results obtained from a 200W prototype. The experimental results reveal that the proposed single stage inverter can achieve high voltage boost, good quality of AC output waveform, and good conversion efficiency.

Keywords:- Single-Stage Boosting Inverter (SSBI); Cycle Controller.

Abstract:- Output dc voltage from Fuel Cell (FC)/Photo Voltaics (PV) needs to be conditioned and converted into ac form before integrating to grid. Normally, two stage converters are used for this purpose. Two stage converters have several disadvantages like low efficiency, more number of components, big size, etc. especially when they are operated at low input voltages. In this paper, a coupled inductor based high performance, high gain, single-stage inverter topology, which can be used for grid connected FC/PV applications or stand-alone applications is proposed. In the proposed topology, dc-dc power conversion and dc-ac power conversion can be done in a single stage. The proposed topology has several features such as high gain, low cost and compact size. This topology suits well for low power applications. The principle of operation, steady state analysis of the proposed topology is presented in this paper. The steady state analysis is verified by a simulation, simulation results of the proposed converter for an ac load is presented.

Keywords:- Single-stage, Grid connected, Buck-boost, Inverter.

Abstract:- High voltage power supplies (HVPS) are widely used to supply vacuum tubes. Regarding to their high efficiency, resonant converters are a choice of HVPS structure. In this application, HVPS is faced with wide variation of the load power. On the other hand, output voltage regulation over wide load range is essential. However, there are several problems dealing with resonant converters such as output voltage regulation and low-efficient performance in a light load. In this paper, a control scheme for a series-parallel resonant converter is presented. This scheme regulates the output voltage of the converter over load variation range. A variable inductor placed as the series inductor in the resonant tank achieves constant maximum power factor. Output voltage is regulated by phase-shift method and the switching frequency is constant. Experimental results are presented to confirm the proposed method.

Keywords:- Resonant converter, variable inductor, power factor, high voltage.

Abstract:- This paper proposes an improved high voltage dc–dc converter with a partial-resonant network (partial- resonant HDC) to be used in electric vehicle applications for enhanced efficiency and power density. In order to achieve enhanced performance compared to the conventional HDC, an approach for the optimal switching frequency is conducted by considering the trade-off between the efficiency and power density. Furthermore, an optimization of the partial-resonant network which enables the designer to place more emphasis on either the efficiency or the power density is concerned. The validity of the partial-resonant HDC performance is verified through the experimental results of the manufactured HDC under the 13.3 kW load condition, and the efficiency is enhanced by 0.73% maximally, and the power density is improved by 14.23%.

Keywords:- bidirectional dc–dc converter, soft-switching technique, resonant converter, electric vehicles.

Abstract:- A dynamic step voltage regulator (SVR) is proposed for an active distribution feeder in the presence of distributed photovoltaic (PV) systems to mitigate excessive tap operations during high PV variability period. Conventional voltage regulating devices, such as on load tap changers (OLTC), SVR, and capacitor banks need to be properly controlled and coordinated while interacting with the smart inverter functionalities to improve power quality, and overall system efficiency. The proposed dynamic regulator settings use a unidirectional communication link from the distribution management system to update its controller set points based on the solar and load forecasts to achieve the desired voltage profile throughout the feeder. In addition, reduction of voltage violation duration and network losses can be attained by implementing dynamic regulator settings. The proposed scheme is tested on a modified IEEE-123 bus test system with integrated PV systems and the performance under different system operation condition and smart inverter functions is evaluated.

Keywords:- Regulator control settings, smart inverter function, voltage control, distributed PV.

Abstract:- In an islanded microgrid where the distributed generators (DGs) capacities are not very large and their output powers are fluctuating, a large capacity installation of energy storage system (ESS) is not ideal method due to its high price. Load control is a preferred control for supply and demand balance. At present, many load controls based on central management system have been proposed to achieve supply and demand balance according to the load capacities or price. However, these existing schemes are not suited for islanded microgrids without central controller. This paper proposes an autonomous control of flexible power electronics loads (FPELs), whose objective is to make the FPELs to automatically participate in supply and demand balance and reduce the response cost with various response prices taken into consideration. Therefore, the proposed control scheme can retain advantages of the traditional distributed load control schemes, while can keep in lower response cost. The effectiveness of the proposed control has been validated via Matlab simulations in islanded microgrid.

Keywords:- islanded microgrid; flexible power electronics loads; autonomous control; response cost.

Abstract:- Active power decoupling (APD) techniques are widely used in single-phase PWM rectifiers under 10 kilowatts, which prove to be efficient in cutting passive component size (usually against bulky electrolytic capacitors at dc side). However, it is found that the reactive power caused by boost inductor cannot be ignored especially in low input voltage, high power situation with large input inductance. Such reactive power could bring an obvious phase-shifted angle φ to dc side current, which contributes to the steady state error in decoupling reference for APD circuit. This paper presents a strategy by modifying φ to achieve the ac-side inductor reactive power compensation (IRPC) without adding any hardware, which could further reduce dc-link capacitance. Compared with the traditional control method that usually neglects reactive power stored by inductor, a more effective power-decoupling IRPC scheme is validated experimentally with a 1kW prototype.

Keywords:- active power decoupling, power ripple, phase-shifted angle, AC/DC converter.

Abstract:- The electrification of aircrafts is transforming the traditional power distribution architectures of the previous century. Turbo-electric propulsion power system features a dc link between turbo-electric generators on each wing tip and the distributed motor drives. Among the challenges of turbo-electric distributed propulsion (TEDP), the stability of the dc bus is vital to safe operation during flight. When these motor drives tightly regulate their output speed, they appear as constant power loads (CPL) on the bus. These CPLs exacerbate the effect of disturbances to the dc bus, such as load transients and voltage sags which can destabilize the system. It is important to keep the system stable without increasing the weight of the system with bulky filters. The Smart Resistor concept has been proposed as one such solution that reduces input capacitor sizes by making the CPL behave as an equivalent droop resistance. This is accomplished by interfacing existing energy storage at the point of load to provide high bandwidth current compensation. This paper first defines stability metrics for a system utilizing the Smart Resistor concept. A case study for a 2 MVA motor drive is used to showcase the improvement of stability using Smart Resistor based on these metrics. Finally, the quantitative improvement in the stability metrics is validated using a scaled down hardware prototype.

Keywords:- Turbo-Electric Aircrafts, Constant Power Loads, Wide-Bandgap Semiconductors, Energy Storage, DC Microgrids.

Abstract:- In both battery operated electric vehicles (EVs) and plug-in-hybrid electric vehicles (PHEVs), a two-stage converter connects the input grid voltage to the battery pack whose voltage varies from 100-500 V, depending on the vehicle size and range. A universal charger, which can address this wide range of battery pack voltages, is suitable for all vehicle architectures. This requirement is achieved by varying the AC/DC converter output voltage using the concept of variable dc link voltage, which is one of the challenges in battery chargers for attaining universal output voltages. This paper mainly focuses on analysis and operating modes for a interleaved boost cascaded-by buck(IBCBB) converter suitable for a power factor correction (PFC) converter. The designed control structure provides a wide degree of control freedom to operate even if the VDC /Vmax (output voltage to peak of Input) less than 0.5. The design considerations for selection of components is also addressed in the paper. Moreover, the proposed converter is validated on the experimental setup and the results are presented in the paper. In addition, a two-stage universal battery charger with wide input and output voltage is been simulated and presented in the paper.

Keywords:- AC-DC power converters, battery chargers, energy storage, power electronics, transportation.

Abstract:- Photovoltaic power plants usually work in maximum power point tracking (MPPT) mode to maximize the output power that deliver to the grid. By increasing the number of installed PV plants, new challenges have emerged in the system such as overloading, overvoltages, and operation during voltage disturbances. So the need for increased ancillary services imposes power reserves in the photovoltaic systems. In this paper, a stable algorithm is used to operate in constant power generation (CPG) mode at the right side of the MPP without any instability problems by using I-V characteristic of the PV panel. A 100 KW PV system has been simulated in MATLAB/Simulink and the operation under a fast change in irradiance has been considered.

Keywords:- Maximum power point tracking, constant power generation, PV system, right side of the MPP.

Abstract:- A modified structure of Z-Source converter as partial power processing (PPP) Z-Source converter is presented which is practically applicable for distributed energy systems such as photovoltaic (PV) systems. With a similar approach the proposed converter is different from basic PPP structure of Z-source converter. Improved efficiency, voltage gain, significantly reduced voltage stress and power rating are the proposed converter advantages. The operation principles of the converter is explained and the equations are derived. Also the proposed converter is compared to full power Z-source and basic PPP Z-source converter in terms of efficiency, power loss, voltage gain and voltage/current stresses. The simulation results are presented to verify the theoretical analysis. A laboratory prototype of the proposed converter is made and the results are compared to simulation results.

Keywords:- partial power processing; Isolated Z-source converter; high step up converter; photovoltaic (PV).

Abstract:- In this paper, an adaptive multi-loop controller for capacitive wireless power transfer (WPT) systems is introduced. The new controller approach combines continuous frequency tracking and matching networks tuning on both the primary and secondary to regulate a target current to the receiving side at best power transfer conditions. This enables to effectively disengage the power delivery capabilities from the cross-coupling interactions between the transmitting and receiving sides, variations of the electrical circuits and capacitive medium. This paper highlights the complex functional relationships of the multi mixed-signal controller, and provides better insights on the dynamics and on the practical implementation of a closed-loop capacitive power transfer (CPT) system. An experimental self-tuned capacitive WPT prototype has been designed and implemented to verify closed-loop operation at the MHz range.

Keywords:- capacitive power transfer, capacitive coupling, multi-loop controller, closed-loop capacitive wireless system, impedance matching, self-tuned system, wireless power transfer.

Abstract:- This paper presents a high-power-density high-efficiency single-phase electrolytic-free offline LED driver that utilizes a novel energy buffer architecture for twice-line-frequency energy buffering. The proposed LED driver comprises two stages: a front-end power factor correction stage, followed by a merged energy-buffering/dc-dc conversion stage. The proposed merged energy buffer architecture reduces the step-down voltage conversion ratio requirement of the second stage dc-dc converter, thus improving its efficiency. This buffer architecture also increases the energy utilization of the buffer capacitors, thus reducing the passive volume of the energy buffer. The PFC stage is realized using a four-switch buck-boost converter and an LLC resonant converter is used to realize the second stage dc-dc converter. A 150-W prototype LED driver utilizing the proposed merged energy buffer is designed, built and tested and the experimental results are presented. The PFC stage maintains a high power factor and achieves a peak efficiency of 97% while the LLC stage achieves a peak efficiency of 93%. The prototype LED driver achieves a power density of 50 W/inch3, while replacing electrolytic capacitors with much lower energy density ceramic capacitors.

Keywords:- LED driver; ac/dc power conversion; dc/dc power conversion; twice-line-frequency; merged energy buffer; four-switch buck-boost converter; power factor correction; LLC resonant converter.

Abstract:- Railway static power conditioner (RPC) has been utilized to compensate power quality indices (current unbalance, voltage/current harmonics and grid-side power factor) simultaneously in AC electrified railway. In this paper, a hybrid configuration including C-type filter (CTF) and RPC is proposed in Scott co-phase traction power system. Some part of the load reactive power is compensated by the CTF, while the RPC compensates the remaining part of the reactive power. Furthermore, harmonic mitigation analysis is investigated for high-order harmonics suppression. By implementing the CTF, the VA rating reduction of the RPC is achieved and the dc-link voltage can be also operated at a lower level for a specific traction load. Without imposing any complexity to the control system, modified instantaneous PQ theory is adapted to obtain the reference currents. A theoretical analysis process is given and simulation results verify the validity of the proposed structure.

Keywords:- Electrified co-phase railway system, railway static power conditioner, c-type filter, high-order harmonics mitigation, VA rating reduction.

Abstract:- High-power modular dc-dc converters are key en- abling components for interconnection of MVDC and LVDC grids, for which both the efficiency and controllability are of great importance. Although the state-of-the-art modular dual-active bridge (DAB) dc-dc converter presents a high controllability with the soft-switching turn-on operation, the peak efficiency is ultimately limited by turn-off losses of semiconductor devices. On the other hand, unregulated series resonant converters (SRCs) operating under the resonant condition can realize a very high efficiency, but presents no controllability of the dc voltage. This paper presents a novel modular dc-dc converter topology with the input-series-output-parallel (ISOP) configuration, which combines SRCs as the majority modules for the bulky power transfer and only a small number of DAB converter modules for the dc-voltage control. Benefiting from the hybrid circuit topology, the proposed converter can achieve a higher efficiency than the modular DAB converter with a reduced complexity in the communication and control, while maintaining the controllability of the dc voltage. The operation principle of this topology and optimization procedure of key design parameters are presented. Finally, the performance of the proposed hybrid modular dc-dc converter is verified by both simulative studies and experiments of a laboratory converter prototype.

Keywords:- Dual-active bridge dc-dc converter, series resonant converter, partial-power regulation, hybrid topology, dc grids, input series output parallel.

Abstract:- This paper presents a high-performance kilowatt-scale capacitive wireless power transfer (WPT) system for electric vehicle charging. This system achieves effective power transfer across a large air-gap by operating at a multi-MHz frequency(13.56 MHz), and by utilizing L-section matching networks that provide gain and reactive compensation. To achieve high efficiency at the high operating frequency, the matching network inductors are constructed as semi-toroidal structures with interleaved-foil coupled windings. This new coupled inductor design greatly reduces the inductor’s ac resistance, with a measured 46% reduction compared to a conventional solenoidal coupled inductor. To further enhance performance, the matching network capacitors are comprised solely by the parasitic capacitances of the system, thereby eliminating on-board capacitors prone to dielectric breakdown and high-frequency losses. A 13.56-MHz 12-cm air-gap prototype capacitive WPTsystem incorporating these innovations is designed, built and tested. This system transfers 2.25 kW at an efficiency of 90%,achieving 29.6 kW/m2 power transfer density. The system achieve seven higher efficiencies at intermediate power levels, with a peak efficiency of 94% at 320 W, and 93% efficiency at 2 kW.

Keywords:- capacitive wireless power transfer; wireless power;electric vehicle; foil wire inductor; coupled inductor; high efficiency; high power transfer density; matching networks; high frequency.

Abstract:- In this paper, heat extractors are embedded into the magnetic materials of the integrated power electronics passive modules. The optimum volume of heat-extracting material may slightly reduce the amount of electromagnetic energy that is processed, but more efficient heat removal yields higher allowable levels of both electromagnetic stress and losses per unit volume in the remaining material. Without influencing the electromagnetic performance, heat extractors provide the potential to improve the power density of passive modules. This paper introduces the mechanism of heat extractors into passive power electronics modules. Theoretical thermal models and simulation are used to investigate factors influencing the module performance and the improvement on power density. Prototypes are built for experimental investigation. The experimental results show great improvement of power density by the application of heat extraction technology.High power density, more than 1 kW/in3 (70 W/cm3 ), is achieved on the prototype.

Keywords:- Embedded heat extractor, passive integrated power electronics module, power density.

Abstract:- This paper proposes a circuit design of single-phase bi-directional on-board charger (OBC) using starter generator and its drive inverter in hybrid electric vehicles(HEVs). There are numerous power electronics components in a HEV. The proposed circuit has a battery charging ability by adding power relays into the generator drive system. Therefore,the conventional OBC can be removed from the vehicle and thus the power density of the vehicle is increased. Because the proposed charging circuit allows bi-directional power delivery from grid to vehicle, a model predictive current controller is proposed to achieve the fast-dynamic response and improve the harmonic characteristic of grid current. The simulation results verify the validity and feasibility of the proposed integrated charging system design and its control method.

Keywords:- Hybrid electric vehicles, on-board charger, model predictive control, bi-directional power flow, grid-connected system.

Abstract:- This paper presents power management of a grid-connected photovoltaic (PV) inverter with battery energy storage system (BESS) for the residential application. The overall system is controlled at the grid level and converter level.At the grid level, the inverter is capable of regulating the power provided by the system controller. At the converter level, the inverter system with BESS can manage the power while considering the priorities of the battery or the grid, e.g., battery first and the grid first. Different controllers are designed to control the battery power, inverter power, and the PV power when their priorities are changed. The experimental results show that with the designed controllers, the system is not only capable of dealing with the local load and source change, but also can participate the system level control by regulating the amount power provided by the upper level controllers.

Keywords:- Battery energy storage system (BESS), photovoltaic(PV), power management, residential.

Abstract:- In this paper we present a single stage AC/DC resonant converter with application in electric vehicles, that can transfer power through an air gap of 10cm and operates over a wide output voltage range. The proposed single-stage AC/DC converter for wireless power transfer system integrates a PFC converter and a three level resonant converter into one. The proposed converter operates at a fixed frequency and provides a wide controllable output voltage (200Vdc~400Vdc) with high efficiencies over a wide load range due to a phase shift control. Moreover, all the switching devices operate with ZVS, and the converter’s THD at full load is small. The feasibility of the proposed single-stage converter is verified with experimental results of a 2kW prototype for wireless power transfer system.

Keywords:- Wireless power transfer system, single-stage AC/DC converter, resonant converter, EV charger.

Abstract:- Common-mode leakage current and double-line-frequency power oscillation are two major challenges of non-isolated single-phase grid-tied inverters. To overcome these two challenges, this paper proposes a new single-phase single-stage inverter for photovoltaic grid-tied systems, which consist of two switches, three capacitors, two inductors, and one diode. The proposed topology allows the negative pole of the photovoltaic panel to be directly connected to the neutral line of the utility grid so that the common-mode leakage current is eliminated completely. Then a mixed modulation strategy combining pulse width modulation and pulse frequency modulation is proposed to suppress the double-line-frequency power oscillation. Two of the capacitors are utilized to handle the power difference between the AC and DC sides, and the other is utilized to implement zero voltage switching. The proposed inverter is also capable of outputting reactive power. The validity of the proposed inverter is verified by simulation.

Keywords:- common-mode leakage current, double-line-frequency power oscillation, grid-tied inverter, mixed modulation strategy, zero voltage switching.

Abstract:- In this paper, a high step-up magnetic-less DC/DCnX converter is designed and experimentally evaluated. GaN transistors are applied in a nX converter topology, yielding ultra-high power density and high conversion efficiency. The absence of magnetic materials results in a constant efficiency throughout the power range; the power capability of the system is only limited by the ratings of the semiconductor devices. To effectively extract the dissipated power, a novel micro-fluidic heat sink is designed, based on micro channels fabricated on Silicon substrate and a laser-cut acrylic manifold. The developed liquid cooling heat sink yields a much smaller volume and higher cooling capability compared to conventional heat sinks. A 10X converter prototype with the integrated micro-fluidic heat sink is experimentally evaluated at various operating conditions and different flow rates for the cooling system. At a transferred power of 1.2 kW the converter exhibits an overall efficiency of 96%, while occupying 260 mL of volume, resulting in 4.62W/cm3, a notable power density for such a high step-up DC/DC converter.

Keywords:- DC/DC converter, GaN transistors, high power density, high efficiency, magnetic-less converter, liquid cooling.

Abstract:- The solar and wind energy-based systems are directly dependent on the weather conditions for power generating. Thus a reliable system that is not affected by environmental conditions is required for residential applications. This study presents designing a consistent power management system (PMS) for solar and wind energy-based residential applications to overcome this problem. The proposed PMS controls a hybrid power generator (HPG) system consisting of a photovoltaic (PV) array and a wind turbine to supply consistent energy to the residential loads without any energy interruption in real-time. The designed PMS checks the demand side power and provides the PV array power to the HPG system in the condition of sufficient solar energy. Unless the PV array does not supply the desired power, the demand side power is supplied by fed by a permanent magnet synchronous generator (PMSG)-based wind turbine and a battery. The required energy is supplied from the grid, in case,the power supplied by the wind turbine and the PV array does not meet the demand. The developed PMS measures the PV panel voltage, battery voltage, and inverter’s output voltage in real time and controls the relay circuits by evaluating these electrical parameters. The experimental results obtained from the developed HPG system verify that the proposed PMS is reliable for residential applications, easily implemented, practical, and presents a low-cost solution to the subject.

Keywords:- wind energy; solar energy; real-time power management; demand-side management.

Abstract:- When a grid-connected inverter is connected to a weak grid, the system may be instable. An adaptive active damper can be connected to the point of common coupling(PCC), which can automatically regulate a virtual resistor to the critical value to stabilize the system. Furthermore, a harmonic-current-reference compensation method is adopted to make the active damper more accurately simulate thev irtual resistor in a wide frequency range. This paper investigates the harmonic-current-reference compensation for the stationary α−β frame, synchronous d−q frame, and decoupled synchronous d−q frame-controlled three-phase adaptive active damper. With the proposed method, the active damper controls the active and reactive power directly and improves the stability of the grid-connected inverters under weak grid at the same time. Simulation tests on the system of a10-kVA three-phase grid-connected inverter and a 3-kVA active damper is carried out to verify the effectiveness of the proposed control scheme of the active damper.

Keywords:- Active damper; grid-connected inverter; active and reactive power control; hybrid frame.

Abstract:- This paper presents a boost dc-dc converter design that maximizes drive-cycle weighted efficiency based on the CAFE standard. A drive-cycle simplification approach is introduced to enable faster yet accurate CAFE-based optimization.The optimization is based on calibrated loss models, including soft switching operation in boundary conduction mode (BCM)using a compact planar inductor. An enhanced thermal management strategy based on additional thermally-conductive layers is proposed to address design limitations related to the planar inductor realization. The design approaches are verified on an experimental 400 V, 11 kW SiC boost converter prototype, which achieves 99% measured efficiency over a wide operating range,and a CAFE-weighted efficiency of 99.1%.

Keywords:- boost converter, high efficiency, electric vehicle power train, optimization, planar magnetics, thermal management.

Abstract:- This paper presents an isolated step-sown DC-DC converter using GaN power device for automotive applications.The works for a power supply from a high voltage main battery with 200V to low voltage auxiliary battery with 13.6V in hybrid electric vehicle. A LLC converter is known as isolated DC-DC converter with high-efficiency. However, when input and/or output voltage considerably fluctuates, efficiency of a LLC resonant converter becomes worse. In order to solve this problem,a DC-DC boost-up converter to mitigate efficiency deterioration for the input and/or output voltage fluctuation is added to a LLC resonant converter. Generally speaking, an additional circuit, the boost-up chopper in this case, also deteriorates the total system efficiency. To avoid the efficiency degradation, discontinuous current mode control and GaN power devices are applied to the boost-up chopper. The DC-DC boost-up converter experimentally achieves 99.03% of conversion efficiency at nominal output so that it has no effect on the total system efficiency. Even though adding a DC-DC boost-up chopper to the LLC resonant converter, a power density expected to 10 W/cc.

Keywords:- GaN power device, Automotive DC-DC converter,LLC resonant converter, synchronous rectifier.

Abstract:- A novel quasi-single-stage unified power quality conditioner integrating distributed generation (UPQC-DG) is proposed in this paper. With the help of quasi-single-stage architecture, the low-voltage distributed generation, e.g., PV modules or energy storages, can directly supply active power to the ac grid or ac load within single power conversion stage.Therefore, in comparison with traditional two-stage UPQC-DG,the power conversion stages are reduced and the overall conversion efficiency is enhanced. A modified SVPWM strategy aiming at realizing most active power transferred within single power conversion stage is discussed. Besides, the power flow through the quasi-single-stage UPQC-DG is analyzed in detail to understand the system operation and design the power converters properly. Experimental results with a 3kVA prototype are provided to verify the feasibility and effectiveness of the presented quasi-single-stage UPQC-DG.

Keywords:- distribution generation, high efficiency, power flow,unified power quality conditioner.

Abstract:- Management of multiple energy sources without implementation of extra communication is challenge. This paper presents an autonomous power management strategy fora grid-connected PV-battery system. The DC-bus signaling method is used to achieve the power line communications so that the system can switch from the different working modes. The experimental results validated that with the proposed control strategy, the overall system can transit automatically between the different operation modes according to the availability of renewable energy, SOC of the battery, and the load.Furthermore, using the BDC as a power decoupling circuit, the bus voltage ripple can be further reduced as well.

Keywords:- DC bus signaling (DBS), energy storage, photovoltaic (PV), power management.

Abstract:- Compared with capacitive power transfer system, inductive power transmission (IPT) system is suitable for electric field coupling at higher frequencies. In the LCC-compensated IPT system, it contains four common mode (CM) inductors, one transformer, two parallel and two series resonant capacitors. However,these passive components occupy a significant space. In order to reduce the volume, an integrated passive device with flexible multi-layer foil (FMLM) integration technology is proposed in this paper. Besides, this paper also introduces the construction, flux analysis and parameter design of the proposed integrated device.Finally, in order to prove the feasibility of the proposed ideas, a simulation model based on Maxwell/Ansoft and a prototype are built for a 2200W-85kHz LCC-compensated IPT device.

Keywords:- IPT system, the efficiency of high-power electric transmission, flexible multi-layer foil integration technique.

Abstract:- This paper presents an instantaneous reactive power reduction method for ripple less resonant bidirectional converter in backward operation. The method is applied to improve an existing converter topology that features high step-up/down capability, high efficiency and zero in-put ripple. The original topology suffers from significant reverse current when transferring power backwards under synchronous rectification. By adding a single bidirectional switch in the circuit, we are able to block the reverse current in the backward operation, which dramatically reduces the circulating current and current stress on the switch. A non-complementary modulation strategy for the bidirectional switch is developed to further reduce the conduction loss,which comes from the use of the bidirectional switch. A 600-W converter prototype has been implemented to show the performance of the converter.

Keywords:- Input current ripple, Synchronous rectification, reactive power blocking, non-complementary modulation strategy, conduction loss.

Abstract:- Air core based PCB winding transformers are gaining wide attention due to low cost and size requirements. A novel application of this transformer is gate drive power supply with low power rating. In this paper, the application of a coreless PCB transformer into a synchronous flybuck converter is presented. It has been shown that use of phase reversal,interleaving and symmetry in winding arrangement can increase efficiency and reduce winding losses considerably. Part to part variation due to PCB design process has been eliminated by adding a secondary side referenced controller. The proposed transformer is capable of providing functional isolation between floating and ground plane referenced supply. Besides smaller footprint, this topology can eliminate cost and increase power density by inserting the winding within the substrate. EMC based analysis is also presented. In conclusion, a six sigma approach to designing planar transformers is presented.

Keywords:- CPT (Capacitive Power Transfer), DFSS (Designfor Six Sigma), IGBT, IPT, VFD (Variable Frequency Drive).

Abstract:- Photovoltaic inverter is difficult to operate in stand alone mode without robust voltage source, which handicaps the development of renewable solar energy. If the inverter works in voltage control mode, it should balance the power flow between the resources and the loads. Utilizing limited power adjustment ability of photovoltaic arrays can improve this performance,which is effective if the assigned power of photovoltaic inverter is less than the maximum power of the arrays. However, if that premise cannot be satisfied, the PV inverter can be vulnerable to disturbance, where reasonable control and mode switch strategy are necessary in this situation. This paper will introduce the scheme of voltage-controlled photovoltaic generator that utilizes the principle of power conversion in synchronous generator. The control method in the situation that the maximum capability of photovoltaic arrays is less than the assigned power of inverter is designed. The proposed method is verified in simulation and hence the effectiveness is proved, which is practical for improving robustness and stability of micro grid integrated photo voltaic inverter.

Keywords:- photovoltaic, inverter control, frequency control, MPPT, active power balance.

Abstract:- Soft Open Point (SOP) is a new power electronic device installed in place of traditional tie switch in a distribution network. It can realize flexible, fast and reliable regulation of feeder flow, improve voltage distribution level and the ability of distribution network to consume distributed generation. This paper analyzes the topology of three-port SOP and establishes the mathematical model of SOP. According to strong coupling and non linearity of the model in the dq reference frame, decoupled feedback linearization control is proposed to linearize the system and realize decoupling control of active current and reactive current. Then linearization method is used to design controller for the linear system. A three-port SOP system is designed based on the MATLAB/Simulink simulation software, and simulation results show that the control strategy proposed in this paper is feasible and can provide new ideas and solutions for the application of SOP in the distribution network.

Keywords:- Soft Open Point, feedback linearization, distribution network.

Abstract:- With the increasing use of electrical equipment,the harmonic pollution and electromagnetic interference of the power grid are becoming increasingly serious. In order to reduce the harmonic pollution of the power grid and meet the requirements of some EMC (25Hz-5kHz) occasions, a new high control precision active power filter is developed in this paper. In order to improve the compensation precision of active power filter, the closed loop control of active power filter based on DQ axis is adopted in this paper.Through the real-time detection and the control of the harmonic current of the grid side, the closed loop control can achieve no error.The analog proportional control is used to improve the dynamic response speed and the steady state tracking effect of the system. At the same time, the digital repetitive control is adopted. The zero error tracking of the AC signal is realized by the principle of the inner membrane. The validity of the proposed control strategy is verified on a 10A APF prototype, and the compensation test results meet the requirements of EMC (25Hz-5kHz).

Keywords:- APF,EMC,high control precision,DQ axis, analog control, repetitive control.

Abstract:- This paper presents a new integrated auxiliary bidirectional multilevel converter for applications in electric vehicle(EV). This converter is modular and is designed to be used to power communication circuits, WI-FI and heating, ventilation, and air conditioning (HVAC). It still requires bi-directional operation to flexibly interchange power from and to the auxiliary system battery. The vicinity of the proposed converter to sensitive loads is certified against the European Norm and North American electromagnetic compatibility (EMC) standards. The new configuration allows replacing the bulky electrolytic capacitors with film capacitors that has longer life, higher reliability, lighter weight and smaller size. EMC preliminary results are given in this paper to show compliance with the certification standard limits. Validation of the proposed configuration was conducted using aSimulink model, PSIM simulation model, and a real- time 750Vdc-3 kW laboratory prototype. The proposed converter shows emission interference as well as design immunity to the neighboring power system on board the electric vehicle.

Keywords:- EMC; PSIM.

Abstract:- A new two-input and multi-output interleaved DC_DC boost converter is proposed. This converter is a high gain and non-isolated boost converter, which can be used in satellites power system. This converter has several dc links with different gains in the output to feed other satellite subsystems.This converter is an interleaved boost converter, so it performs better than the conventional converters. The main tasks of this converter in the subsystem of satellite energy supply are maximum power points tracking (MPPT), battery charging and line dc voltage regulation. Normally, three separate converters are required to provide these tasks. By increasing the power electronic devices, the volume and weight of the satellite will go up. This is not desirable, therefore, must use a comprehensive circuit to perform the three above tasks at the same time. The proposed converter has an integrated structure with only four switches that controlled by different duty cycles. Also this converter has a uni-directional input for connecting the solar array and a bi-directional input for connecting the battery.Based on charging or discharging state of the battery, three operation modes are defined for this converter. One of the prominent features of the proposed converter is the battery bases grounded, so the noise cannot damage the battery and soon increase the useful life of battery. Theoretical analysis of the proposed converter is verified by simulation results for different operation conditions.

Keywords:- Multi input & multi output, Non-isolated boost converter, Interleaved technique, High gain boost converter,Satellites power supply

Abstract:- The paper will focus on an innovative control applied to a modified LLC converter able to independently regulate two output voltages. The topology and the characteristics of the system will be explained, and the performance will be compared to a traditional LLC with post regulation in terms of efficiency, and dynamic regulation. The algorithms, the equations, the implementation will be detailed.A prototype of the system was designed based on a LED TV power supply. This application is particularly suited for the topology since the back light and the rest of the circuitry require independently regulated voltages.The implementation is focused on the design of an AC/DC converter, even if the control system itself can be applied also to other type of power converters.

Keywords:- LLC, resonant converter, dual output.

Abstract:- Power sharing inaccuracy between distributed generators (DGs) in island microgrid, especially the reactive power sharing inaccuracy, is a predominant problem. Therefore, in order to improve the accuracy of reactive power sharing, this paper proposes a novel island microgrid power sharing strategy based on the variable droop coefficient control to deal with the inaccurate reactive power sharing phenomenon caused by the nontrivial feeder impedance. The proposed method varies the reactive droop coefficients of all the DGs to estimate the feeder impedance mismatch and adopts a virtual impedance feedback loop to revise the virtual impedance to make the equivalent feeder impedance inversely proportional to the corresponding capacity of the DG. This process, which is activated by the low-bandwidth synchronization signals from the central controller, guarantees the accurate reactive power sharing between DGs in island microgrid. Moreover, active and reactive power fluctuations are avoided compared with other coupling power sharing method. Simulation results demonstrate the feasibility of the proposed method.

Keywords:- Power sharing, Distributed generator (DG), Island microgrid, Variable droop coefficient control, Virtual impedance.

Abstract:- The use of FPGA based system on chip SoCs to implement controllers for Power Electronics applications is becoming increasingly popular. This is mainly due to the flexibility that allows to have in the same device a processor able to execute high level control algorithms, and a programmable logic where complex algorithms can be hardware accelerated. This hardware implementation is usually carried out using HLS tools. All this complexity makes the design and verification tasks difficult. HW/SW co-simulation has proven to be a very efficient technique to fulfil this challenging SoC designs. Simulation speed is a critical feature and is mainly limited by the processor simulator, especially when the device has several cores, as it happens with MultiProcessor SoCs (MPSoC). In this case, using a very fast processor simulator, such as QEMU, is crucial to achieve reasonable simulation speed. This work describes Virtual Platform based on QEMU, SystemC and HLS to co-simulate hardware and software designs in a fast way. A smart-switcher design for synchronization of micro-grids is taken as case study. It controls the connection of a micro-grid to mains when both of them have similar voltage and phase. It includes a dual PLL, implemented in HW, that provides all the information to the control algorithm executed in the processor. The simulation speed of the proposed Virtual Platform is analyzed under different working conditions and compared with other solutions.

Keywords:- Co-simulation, QEMU, SystemC, HLS, PLL.

Abstract:- Abstract—Accurate high-frequency core loss measurement is critical for power converter design, especially for integrated voltage regulator application. Partial cancellation method is a promising candidate, which can cancel out loss error caused by phase discrepancy without finely tuning cancellation component values. However, it assumes a small value of phase discrepancy, which is not valid for high frequency. This paper performs the error analysis in this case and proposes an initial compensation method to eliminate this error. Finally, experiments are performed to verify proposed method up to 60MHz.

Keywords:- high frequency, core loss measurement, partial cancellation, initial compensation.