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A comprehensive analysis on a novel topology of Boost converter with passive LC3 configuration has been proposed in this paper. The proposed DC-DC converter achieves a higher efficiency when compared with conventional Boost converter, having maximum efficiency of 98.26%. Its AC-DC topology also achieves similar results, having better performance in efficiency, power factor and THD. Power factor and THD are further improved by integrating a PI controller, achieving a power factor of 0.9904 and THD of 11.67%. Finally a comparison between rippled and unrippled DC source is shown in this paper. All the results are validated by using PSIM.

Single module of ZPUC topology is presented in this paper which can be operated with single DC source. Although ZPUC has one more capacitor compared to its counterpart PUC converter, it requires single DC source instead of three isolated DC sources in three-phase system which is a great advantages to reduce the cost and bulkiness of the system. It also reduces the total components counts of the converters in comparison to the most popular types of multilevel converters. Active voltage balancing through Phase shift pulsed width modulation (PS-PWM) strategy has been used to balance the voltages of three flying capacitors. ZPUC topology based on the 5-L inverter is investigated in Matlab-Simulink to validate the performance of the single module of ZPUC topology.

This paper suggests a Hybrid Switched-Capacitor 9-Level Boost Inverter (HSC9LBI) topology that provides quadruple voltage-gain. Capability of feeding zero or low power-factor load types as well as natural voltage balancing of capacitors are other merits of suggested HSC9LBI. Two half-bridges are utilized to create bipolar voltage-waveform. The suggested HSC9LBI requires single DC source, which results in compact size. Different operational modes have been elaborated. The comparison and simulations results have been presented to verify superiority and suitable functionality of suggested configuration.

With the development of DC source and load, the AC/DC hybrid distribution network has become the development direction of the future distribution network. The calculation of its total supply capability can effectively guide its planning and operation. In order to accurately calculate the power supply capacity of the AC/DC hybrid distribution network, the load transfer method under N-1 fault was first analyzed. Second, a total supply capability calculation model considering load balance was proposed. The operating characteristics of different types of loads are considered in the model. Then the proposed model is solved by NSGA-II. Finally, an example is used to verify the effectiveness of the proposed model and algorithm, and the total supply capability and bottlenecks of AC/DC hybrid power distribution networks with different structures are compared and analyzed.

In this paper, a novel single-phase five-level inverter is proposed. It is composed of eight switches and one flying-dc-source. Compared with the conventional active-neutral-point-clamped five-level inverter, the proposed structure has the same number of active devices and it does not require any sensor or balancing circuits to control the split dc-link capacitors. Thereby, the proposed converter reduces the cost and the complexity of the control system. Additionally, the proposed inverter has the capability of boosting the input voltage by a factor of two, which means it allows a reduction of 50 % in the DC-link voltage requirement and it does not require an intermediate DC-boosting stage for applications such as, photovoltaic panels and full-cells systems, characterized by a low and unregulated input voltage. Experimental results have been performed in order to validate the theoretical analysis of the proposed system.

Development of reduced components count switched-capacitor (SC) inverters is in the recent trend for photovoltaic (PV) power processing and high frequency ac systems. The self-voltage balancing without complex control scheme and voltage gain features makes SC based multilevel inverters (MLIs) a perfect choice for PV applications. This paper presents a SC based seven-level MLI (SC7MLI) with three-phase extendibility using a single dc source. The output voltage is boosted to three-times the input magnitude with the aid of natural voltage balancing and using fewer components compared to prior-art MLIs. The proposed topology uses only 9 and 21 switches in single-phase and three-phase extensions, respectively. Simulation results under different steady-state and dynamic conditions validate the feasibility of the proposed design that is further warranted by several experimental results.

The paper describes a digital low-frequency ac voltage source with amplitude stability better than 10⁻⁶ V/V per hour. It was developed to be used as a transfer standard for calibrations with ac Josephson systems and fast synchronous ac-dc transfer measurements. Its low-distortion and superb phase adjustment resolution makes it suitable for impedance measurements as well., Conference on Precision Electromagnetic Measurements (CPEM 2020), August 24-28, 2020, Denver, Colorado [Held Virtually]

A new multilevel inverter is proposed in this paper, in which the capacitor and transformer are employed to generate the high voltage levels compared to the used elements. In this proposed structure, only one DC source and transformer are used. In the extended structure, only the number of capacitors and switches is increased as a result the costs are reduced and implementation is simplified. In order to evaluate pros and cons of the proposed inverter, first it is compared to the conventional transformer-based structures, and then its performance is evaluated through simulation in MATLAB by considering a 9-level configuration.

Multilevel inverter technologies have emerged in recent years as a very significant alternative in the area of medium and high voltage applications. For controlling the cascaded H-Bridge MLI with only one DC source (known as hybrid cascaded MLI (HC-MLI), many hardware modifications and control techniques are proposed. Predictive control (PC) is one of the best non-linear control techniques which is popularized in the area of power electronics recently. In this paper, a modified MPC technique is proposed to control the output current and balancing of capacitor voltage in HC-MLI. Normalization methods and weighting factors are used to give better results in this work.

Multilevel inverters are costly when it employs a higher number of dc sources and power semiconductor switches. This paper suggests a topology which uses one dc source, and three self-balanced capacitors and six switches to generate nine-level along with polarity generation using H-bridge. The switching scheme is made in such a manner that capacitors get balanced automatically. The modes of operation and charging and discharging of capacitors is presented with illustrations. The simulation result for this topology is verified on MATLAB 2018a. The simulated results show the output voltage levels, capacitor voltage profile.

A new nine level inverter is presented in this paper. It combines PUC and NPC topologies to create a new competitive converter that makes use of small count of power devices to generate more voltage levels. A PWM technique is designed to insure the self balancing of capacitors voltages. Moreover, no filters or regulation loop is required which permits a low inverter and installation cost. Authors make use of Matlab Simulink environment to perform the simulation of the proposed concept. Dynamics of the latter was verified against load and DC source voltage change.

A new family of 7-Level Boost Active Neutral Point Clamped (7L-BANPC) circuits is proposed in this paper. The proposed topology is derived from the conventional ANPC by adding one additional capacitor to boost the voltage and increase the number of output voltage levels. The proposed topology generates seven output voltage levels using one dc source and two flying capacitors. A specific modulation strategy is presented in this study to provide self-balancing for the flying capacitors of the proposed inverter. Theoretical analysis and the operational modes of the proposed 7L-BANPC are presented in this paper. Highlights of the simulation of the proposed inverter are presented to validate the proposed topology. A scaled-down prototype has been built to validate the workability of the proposed topology.

This paper presents the implementation of a bidirectional multi-level voltage inverter, isolated converter based on a multi-cell architecture for battery charger applications. Dual Active Bridge based DC to DC isolated converter cells are cascaded with H bridges which are then associated in series to implement a multi-level topology able to produce AC waves from DC source and vice versa. The operating principle is provided along with converter main advantages and drawbacks. A special attention is dedicated to the control part. The operation of the multi-level converter is validated with experimental results. A special care is applied to efficiency measurements. Efficiency and power densities are provided to highlight the interest of the converter.

In this paper, a multilevel single-phase converter with injection transformers and two dc links is proposed and applied as an inverter. The basic configuration has five two-level IGBT legs, two injection transformers, one dc source, and one floating capacitor. When isolation is not required, one transformer can be removed. The generalization of the configuration is presented. The calculation of the transformers turns ratios and dc-link voltages to improve the number of voltage levels is provided. The proposed configuration is compared with cascaded H-bridge and a single-phase shared-leg converter with one dc link in terms of several characteristics. Based on semiconductor losses analysis, the proposed configuration is more suitable than the conventional ones for high-voltage low-current applications. Experimental results are shown to demonstrate the feasibility of the system.

Nurses response time to patients call has not been the best as a result of the stress and manual nursing call systems available in many hospitals. This situation has caused a lot of dissatisfaction among patients admitted. This study seeks to provide an improvement on already existing nurse call systems. Despite the existence of nurse call systems that make use of audible signal, nurses still need to manually search for patients who called for their assistance. Hence, this study designed and implemented an automatic nurse call system that uses an audiovisual signal to assist nurses find the location of the patient and reason for admission. An experimental approach was adopted while an electronic device based on Arduino board was designed and constructed. The system operates on 5VDC and can be powered with a DC source operating within the range of 9-32V. To test the communication efficiency of the design, systems data were recorded on system's response time. The average response time of 0.24 seconds was obtained with 15 sampled inputs.

This paper proposes to use the double-sided LC compensation circuit to realize the long-distance and high-power capacitive power transfer. The targeted transfer distance is 150mm for the vehicle charging application, resulting in a loosely-coupled system. The circuit working principle and the transfer efficiency are provided, which indicates the duality with the conventional series-series compensated inductive power transfer system. Using the same capacitive coupler, two load conditions (the constant resistive load and the constant voltage load)are analyzed for the practical applications. The analysis of the CPT system provides the guideline to design and optimize the LC-compensated system. The experimental results show that kW level power transfer can be achieved through 150mm distance with dc-dc efficiency from the dc source to the dc load to be around 88%.

The 9-Level Packed U-cell (PUC9) inverter topology is presented in this paper. It uses eight switches, one DC voltage source and two auxiliary capacitors to generate a 9-level voltage at the output. Obtaining two small size of flying capacitors through proper voltage balancing technique integrated into the modulation unit and without using the complicated external control system that may increase its reliability is the innovation of this article. This topology offers a low-cost inverter compared to the other similar 9-level inverters due to the reduced number of devices and simple voltage controller. PUC9 topology is chosen by trade off between redundancy of states and voltage levels at the output of inverter by selection of suitable proportion of voltage at capacitors than each other and DC source. The stand-alone operation of the PUC9 inverter with implemented voltage balancing technique is investigated through simulation analysis in Matlab-Simulink and results are discussed in details.

Transcutaneous energy transfer (TET) using inductive power transfer is a promising technology for powering implantable medical devices without the need for percutaneous power cables, removing a long-term infection risk. Compared to a driveline, a TET system will produce more heat. The dominant contribution to body heating is ohmic losses in skin contacting and implanted components. This paper reports on using the body’s thermoregulation mechanisms to dissipate the heat of a TET system. The ohmic losses in the primary coil of a TET system were replicated with a DC source. The coil was fixed to human participants and the temperature at the skin was measured with the coil exposed to air, and when insulation covered the coil. The highest temperature recorded was 39 °C, 2 °C lower than the regulatory limit of 41 °C. These results are supportive of using the body to dissipate heat from a TET system.

A comparative study of two stage boost converter fed VSI and a single stage ZSI for solar photovoltaic (PV) based single phase application is presented in this paper. With the inclusion of an impedance network between VSI and the DC source, a single stage conversion from DC to AC is achieved. This paper describes the constructional and operational features of boost fed VSI and ZSI. The boost factor of the ZSI is controlled by injection of shoot through period using simple boost control technique. To demonstrate the application to PV, the modelling is done using MATLAB/Simulink and the effects of practical operational circumstances are represented.

—A QBC (Quadratic-Boost-Converter) for -MLI (Multilevel-inverter) fed IM (Induction Motor) (QBCMLIIM) is proposed here. Quadratic boost-converter with multilevel-inverter is an alternative system in between the DC source and the motor. This work proposes quadratic boost converter between the DC source and inverter. The proposed effort considers closed- loop response of QBCMLI (Quadratic- boost-converter multilevel-inverter)-system accompanied by PI and Fractional-Order-PID-controllers (FOPID). The objective of the proposed system of converter is to sustain steady-speed of the induction- motor-drive circuit-modules is expanded for PI& FOPID-controlled-systems. The mat lab outcome attained illustrates a developed dynamic-performance by using FOPID-controlled QBCMLIIM system. The experimental results of QBCMLIIM-system are compared with those of simulation-ones.

This paper presents a single DC source five-level photovoltaic inverter topology for a stand-alone photovoltaic (PV) system. The proposed PV converter system consists of a five-level inverter and a buck DC-DC converter. The DC-DC converter that embedded in the inverter structure is used to realize the maximum power point tracking (MPPT) in various environmental conditions (temperature and irradiation). Also, as the studied system is stand-alone PV system, a battery energy storage system (BESS) is also included which consists of a bidirectional buck/boost DC-DC converter and a battery energy storage. The BESS is connected to a branch of the DC-link and controls the DC-link voltage while managing the battery energy. One of the main advantages of the proposed converter is that the buck DC-DC converter which is in-charge of MPPT, deals with partial power of the PV and hence the system efficiency would be improved. The simulation results using MATLAB/ SIMULINK confirm the performance of the proposed topology in different scenarios.

Multilevel inverter plays a crucial role in industrial applications. The performance of cascaded multilevel inverter (CMLI) with reduced switch count is analyzed in this paper. If the switches have been increased the switching loss and THD will increase. The preferred topology is simulated for seven level and fifteen level by considering isolated DC source and PV. The reduced % THD is identified compare to other topologies. Four switches continuously working at fundamental switching frequency is considered as one of the advantage of the topology.

An LED driver is presented using parallel loaded resonant converter. Output voltage of this converter added to a dc source to feed the lamp load. One voltage source supplies majority of lamp power directly and other supplies a small power through parallel resonant converter for regulation. This driver features zero voltage switching (ZVS), high efficiency and simple control. Illumination control is incorporated using PWM dimming. A 26 W prototype has been developed to confirm its validity.

Cascaded H-Bridge (CHB) inverters may have some of its cells with a bidirectional power flow between the source and the load for some dc-link voltage ratios and modulation indexes, regardless of the load power factor. Considering this, in this paper switching strategies for single-phase multilevel CHB inverters are presented for applications in which the regenerative mode is not desired, forcing all the cells to have either null or positive power flow towards the load. In order to validate the proposed techniques, a study with single-phase CHB invertes composed of two and three cells is made. The converters equations and level shifted pulse width modulation (LSPWM) technique are given. The topologies are compared with different dc-link ratios in terms of operation range and power distribution. Simulation and experimental results are provided to validate the performance of the systems.

In this paper, three multilevel single-phase converters with two dc sources and two shared legs are proposed and applied as inverters. One configuration has five legs and the other has eight legs. The configurations utilize injection transformers and, when isolation is not required, one transformer can be removed of proposed and conventional configurations. The calculation of the transformers turns ratio that improve the system symmetry is provided. The proposed configurations are compared with cascaded h-bridge and a single-phase shared leg converter with one dc source in terms of several characteristics. Compared with the conventional configurations, the proposed ones have more levels per transformer when the configurations have the same number of legs. The proposed configurations are interesting in terms of semiconductor losses for high voltage and low current applications. Experimental results are shown to demonstrate the feasibility of the system.

In this paper, a Cascaded H-Bridge Multilevel Inverter (CHBMLI) is proposed and designed with single dc source employing single-phase transformers to operate as a shunt active filter for harmonic reduction. The paper studies the complete architecture and control logic of the proposed multilevel inverter. For harmonic current extraction an improved instantaneous active and reactive power control technique is used for reference current generation. Phase shifted PWM technique is used for the modulation of CHBMLI. Finally a seven level CHBMLI is developed to operate as a shunt active filter. The proposal and performance are validated through simulation results.

In this paper, a novel structure of cascaded multilevel inverter (MLI) is proposed. Each module of the proposed MLI consists of four numbers of DC sources, seven unidirectional and 2 bi-directional power switches. Each module possesses the capability of generating bipolar voltage level at its output terminals with the help of H-bridge. Hence, the topology is analyzed for both symmetrical and asymmetrical DC source configurations. Extended structure of the proposed MLI topology has been studied where n numbers of basic unit connected cascaded. Two types of asymmetrical DC source configurations have been proposed. As compared with existing MLI topologies, the proposed MLI requires lower components such as switching devices, driver circuits to generate specific number of output voltage level. This further reduces the size and cost of the inverter system. The topology requires less number of conducting switches to generate maximum voltage levels that indicate to lower switching and conduction losses. Extensive simulation studies of 9 levels symmetrical and 13 levels asymmetrical proposed MLI have been done in Simulink /MATLAB. The different results of simulation studies prove the effectiveness of the proposed topology.

In this paper, a new symmetric basic unit for nine-level converter is proposed and the extended version of basic unit is recommended for higher number of voltage levels. In order to show the advantages of proposed multilevel converter, the comparison results with other multilevel converters are provided. The comparisons show that the number of switches, blocked voltage on switches and the number of dc sources are reduced. To validate the performance of proposed converter, a typical 13-level converter is simulated using MATLAB/Simulink software and is tested in laboratory based prototype model.

In this paper, a Cascaded H-Bridge Multilevel Inverter (CHBMLI) is proposed and designed with single dc source employing single-phase transformers to operate as a shunt active filter for harmonic reduction. The paper studies the complete architecture and control logic of the proposed multilevel inverter. For harmonic current extraction instantaneous active and reactive current control technique is used in steady state and transient condition. In order to have a better comparison, phase shifted PWM and in phase disposition (IPD) PWM technique are used for the modulation of CHBMLI. Finally a seven level CHBMLI is developed to operate as a shunt active filter. The proposal and performance is validated through simulation and experimental results.

Demand of Battery Storage System (BSS) in power engineering applications has been increasing extensively in past few decades specially because of the emerging new concepts such as DC-micro grid, Hybrid grids, renewable energy systems, electric vehicle etc. Particularly, in the developing countries, more attention has been paid towards the battery storage systems to maintain sustainable power systems while eliminating low power quality issues. The purpose of this research is to compare the efficiencies of AC and DC sources for the BSS charging and discharging in same experimental setup to achieve in a reasonable ground. Moreover, it covers the impact of charging efficiency of DC power source compared to the AC power source through measurement and estimation at residential level in City of Karachi, Pakistan. Alongside with study, the impact on carbon footprint has also been analyzed.

This paper presents a thorough study on Five-Level Packed U-Cell inverter called PUC5. The main advantage of PUC5 topology over other popular multilevel ones is the redundant switching states, which facilitate the voltage balancing of the flying capacitor in its configuration. Switching states of the PUC5 inverter are analyzed to ensure an easy voltage balancing process. That voltage controlled auxiliary capacitor helps generating five identical voltage levels at the output using a single DC source. A full comparison is done to other 5-level inverter topologies to reveal the dominant features of the PUC5 structure. Moreover, some discussion on the controller design for the PUC5 inverter is conducted in grid-connected applications which indicates similar procedure performed for conventional 2-level ones due to featuring single-dc-source configuration. Various experimental results are shown in each discussion for better understanding.

The paper presents a microgrid structure, based on wind and photovoltaic (PV) renewable energies inputs, implemented in a dedicated configurable microgrid laboratory. The wind turbine is realized through a Hardware-in-the-Loop (HIL) emulator. PV energy can be taken from a set of panels or from a programmable DC source, which can implement the I–V characteristics of the real system. The microgrid configuration, its components and functionality are presented also through experimental results.

The underground coal mine is dangerous environment with gas1. In long term operation, the insulation resistance of cable decreases, and then leads to leakage. This can result in a threat to human and production safety. The leakage fault signal is weak, and the protection methods have no selectivity. The improvement of the protection method for additional DC source is proposed in this paper. The leakage fault model of system with additional DC source is made, and the fault characteristics are given. Through analysis of the AC and DC leakage circuits respectively using the superposition theorem, the mathematical analytic expression of the fault signals is obtained. The new leakage selection method can extract the DC component from zero-sequence current, and calculate the leakage resistance of each line directly; the leakage line can be detected easily. The simulation model of MATLAB is established to verify the different leakage faults of 660V system, the results show that this new leakage selection method is simple, accurately, effectively, and that can be implemented simply.

Many devices need DC source with low ripple for normal operation. Three-phase bridge rectifiers are most commonly used as the base unit in the source. A simulation model built in MATLAB/SIMULINK is used to analyze the operating of DC source under unbalance mains. The simulation results characterize quality of output voltage versus unbalance of phase voltage.

With the development of HVDC technology, the demand of HVDC circuit breaker is more and more urgent, where the testing standards for HVDC circuit breaker is still absent. It's impractical to carry out test in the real HVDC system at present. The high-power HVDC source is also a high-cost scheme. Therefore, in most of the experiments of HVDC circuit breaker, the current is supplied by AC source. In this paper, two experimental schemes based on LC source for HVDC circuit breaker are studied. The interruption process is simulated and compared among the DC source and LC source with two sets of parameters.

A fifth and seventh order harmonic elimination scheme for IM drive with a multilevel dodecagonal voltage space vector structure using a single DC source is proposed in this work. Single DC source requirement makes four quadrant operation of the drive system simpler compared to the multilevel do-decagonal structures presented in literatures before. The space vector structure consists of six concentric dodecagons, combining the advantages of multilevel operation as well as dodecagonal structure. The topology consists of a three-level flying capacitor (FC) inverter cascaded with a capacitor fed H-bridge (CHB) inverter. The FC inverter operating at high voltage switches in a quasi-square wave mode whereas the CHB inverter operating at a lower voltage switches at high frequency to remove the harmonics generated by the FC inverter. Switching losses are low, both in the FC and CHB inverters. Experiment results for open-loop V/f operation are included in this paper showing the effectiveness of the drive scheme.

In this paper, a novel common-mode voltage (CMV) elimination scheme is proposed for five-level active neutral-point clamped (5L-ANPC) inverters, which is based on the space vector PWM (SVPWM). The proposed SVPWM scheme utilizes only 19 voltage vectors producing a zero value of CMV among the whole 125 voltage vectors of the 5L-ANPC inverter. This scheme is also able to control all capacitor voltages by selecting redundant switching states of the inverter appropriately. Therefore, the inverter can be supplied by a single DC source such as a simple diode rectifier. The validity of the proposed SVPWM scheme is verified by simulation results.

This paper proposes an algorithm technique for an asymmetric cascaded multilevel converter with one floating cell with reduced number of calculation. This control approach permits a unique DC source generate three-phase current with one main cell and one floating cell per phase. Main cells are handled by using a space vector control and floating cells are controlled by a predictive control algorithm technique. Floating capacitors voltages are controlled to maintain an asymmetry to maximize the number of load voltage levels with a reduce number of calculation, selecting only near vectors of previous solution. Results are presented in simulations.

Now a days the growth of interest in multilevel inverters has been increasing because there are enormous applications of there in FACTS and industrial drives etc., Although there are many topologies of multilevel inverters in literature, popular among them are cascaded H-bridge. In general the control methods of these cascaded inverters are designed an assumption of having all dc source voltages same for all H-bridges. This paper discusses the abilities of cascaded multilevel inverter to produce more output voltage levels with same number of H-bridges, but with different input voltage ratios. The ideal nature of input dc voltage sources is shown as an advantage in this paper. The proposed inverter is then used to feed an induction motor drive and the simulation results are shown.

Paper narrates the optimization of residual flux in network transformers by using MATLAB Simulation. The purpose of the paper is to mitigation a large inrush currents taken by various transformers when a feeder is energized. Here Time-domain simulations are used to prove that a small-power device can substantially reduce the residual flux of all transformers simultaneously. The device used in this paper consists of a low-voltage dc source. Before a feeder is re-energized, the residual flux is reduced to a minimum level and as a consequence, the large inrush currents are reduced to an acceptable level. This greatly improves the probability for the feeder to be successfully energized when otherwise a false trip would have occurred. Inrush current reductions of more than 60% are obtained at the head of the feeder.

This paper deals with high boost voltage inverters that improve upon conventional Z-Source inverters. The conventional Z-Source inverter has a impedance network for buck-boost function to interface the DC source and inverter bridge. This proposed Improved Trans-Z-Source inverter has a transformer to obtain high voltage. This proposed inverter has increased voltage boost gain, reduced voltage stress and high boost factor due to the use of transformer. We can able to obtain high voltage from this inverter by making the turns ratio of the transformer more than unity. This paper presents the operating principles, analysis and simulation results of Improved Trans-Z-Source inverter and compares with the conventional Z-Source inverter. Both the shoot-through states and the turns ratio can be regulated to control the boost voltage gain.

Experiments play the decisive role in knowledge acquisition in physics education. Remote experimentation is one of the possibilities to conduct experimental activities at all levels of education. In the paper, we present the example of the utilization of remote experiments - real and virtual - in secondary school physics education. The education activities were designed in accordance with the strategy of education Integrated e-Learning. Here, the students' active participation in education process is crucial. As real remote and virtual experiments are the basic components of the strategy, we also present the experiments used in the education - the real remote experiment “Source of DC voltage” (http://remotelab7.truni.sk) and the virtual experiment “Circuit Construction Kit” (http://phet.colorado.edu/en/simulation/circuit-construction-kitac-virtual-lab).

Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation. Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation.

Cascaded H-bridge multilevel inverters have been very popular in medium-voltage applications. The hybrid CHB multilevel inverter, using dc supplies with different voltages, is an improvement of cascaded H-bridge multilevel inverters. The main advantage of hybrid CHB multilevel inverters is the optimization of levels with a minimum number of power supplies. But in some occasions, there can be only one dc supply. So this paper realizes it in the hybrid CHB inverter by using a high frequency link. This method has the advantages of low total harmonic distortion and small volume. The circuit of the inverter, power distribution and control strategy are deeply analyzed; also principle diagram of control circuit is given. At last, the correctness of this converter is verified through simulation tests.

Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally.

This paper mainly deals with three different topologies of cascaded H-Bridge multilevel inverter. The Existing Topology is a general type of multilevel inverter and has two DC sources for each phase. In Proposed Topology-I the number of DC sources has been reduced to one for all the three phases and the usage of transformers comes into picture. Proposed Topology-II has also only one DC source for all the three phases and the number of switches has been reduced than compare to all other proposed topologies of Cascaded H-bridge multilevel inverter. MATLAB simulations has been carried out for all three Topologies and compared with each other.