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In this paper, a developed structure is proposed for high step-up nonisolated noncoupled inductor based multiport dc–dc converters. The voltage gain per number of devices of the proposed topology is higher than that of similar topologies. This means that, by using the same number of devices, the proposed topology can generate higher gains than other structures. In other words, the proposed topology utilizes less number of devices for producing the same voltage gain, which leads to less total cost, size, weight, and complexity. Despite high voltage gain, the normalized peak inverse voltage (NPIV) on switches/diodes is low. Higher number of input ports leads to higher gains and lower NPIVs on devices. The load energy can be absorbed and stored in first input unit. Modularity, simple structure, continuous input currents, and low input current ripple are the other profits of proposed topology. Low/medium power applications are suggested for the proposed structure. Proposed topology has been explained and operational modes along with steady-state analysis have been discussed. For better verification, the proposed topology has been compared with several multiport high gain converters. Comparison results confirm the advantages of the proposed topology. Finally, the proper performance of the proposed topology has been validated by experimental results.

This article proposes a single-phase double-source 27-level basic inverter structure based on Switched-Capacitors (SCs) circuit for renewable energy sources. The extendibility, low Blocking Voltage (BV) on semiconductors, step-up capability, and self-voltage balancing of capacitors are the main advantages of the suggested basic structure. Using double H-bridges to generate bi-polar voltage waveform, the blocking voltage on the semiconductors limit to only 0.692 Vo,max. The Average of Normalized Blocking Voltage (ANBV) on semiconductors of basic topology is only about 33.52%. Two extended structures have been presented with higher output voltage steps and boosting factors. The first extended topology composed of two (right and left) Generalized Switched Capacitor based Modules (GSCMs), results in reduced sources (only 2), increased steps, low BV on semiconductors, and boosting factor of 2n (n: number of SC Cells). The second extended topology can be realized by applying more cascaded Switched-Capacitor Modules (SCMs), which benefits from quadruple-gain and increased levels (9m, m: number of cascaded modules). The suggested topologies properly supply the zero or low power-factor load types. The superiority of proposed configurations over recently presented similar structures has been compared and verified. The experimental outcomes of the basic topology have also been provided to validate its correct operation.

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.

A single-phase step-up switched-capacitor based 27-level inverter topology is proposed that is capable of supplying resistive-inductive (R-L) loads. The suggested structure produces 27 voltage steps and gain of 1.3 with 2 DC supplies, 13 unidirectional switches, 13 driver boards, 2 capacitors, and 1 diode. The voltage balancing of capacitors takes place naturally, which eases the control of converter. The low voltage ripple on capacitors leads to low Total Harmonic Distortion (THD=1.9 % ) and better power quality, which reduces the size of end-side filter. The reduced elements, low Normalized Standing Voltage (NSV) and low Total Standing Voltage (TSV) on semiconductors are the other advantages. The application of 2 full-bridges imposes less Peak Inverse Voltage (PIV) on output-side switches. Also, the employment of fundamental frequency (nearest level) method for switching pulse generation reduces the switching losses. The comparison and simulation outcome highlight the benefits and correct operation of suggested inverter.

This paper introduces a novel basic single-phase Switched-Capacitor Based Multi-Level Inverter (SCBMLI) topology that benefits from modularity, boosting capability, self-voltage balancing of capacitors and low Blocking Voltage ( $BV$ ) on switches. Due to application of developed H-bridge, only 2 switches ( $S_{2}, S_{5}$ ) experience maximum $BV$ , which leads to reduced Total Blocking Voltage ( $TBV$ ). The suggested basic topology employs only 2 DC sources, which remains constant at extended versions. The basic unit can be extended by increment of switched-capacitor cells to reach more steps and/or larger boosting factors. To verify different features of suggested topology, it has been contrasted with novel similar structures. Then correct performance of suggested topology has been certified by simulation results.

This paper suggests an improved basic single-phase 35-level inverter unit that consists of 4 DC power supplies, 4 capacitors, 10 switch/diodes and 10 gate driver circuits. The basic unit employs two DC links constructed by two cascaded capacitors in parallel with $V_{L}$ and $V_{R}$ DC sources. The use of capacitors not only has led to increased levels, but also has reduced the DC sources and converter cost. The voltage balancing of capacitors is done naturally which eases the control of proposed topology. Since, the proposed structure is based on developed H-bridge, it can produce positive, zero and negative voltage steps. Also, the suggested topology has suitable performance for resistive ( $R$ ) or resistive-inductive ( $R-L$ ) load types. Based on comparison results, the suggested structure has more steps per devices than similar configurations. The credits of suggested topology have been certified by comparisons and simulations in PSCAD/EMTDC software.

This study proposes a modular high voltage gain structure for non-isolated non-coupled inductor based multi-input (NINCIBMI) dc-dc converters. Proposed topology can produce higher voltage gains per number of components (switch, diode, capacitor and inductor) than other NINCIBMI topologies. In other words, the proposed topology uses less number of components for achieving the same voltage gain. This property can lead to reduced cost, size, weight and complexity of topology. Also, proposed topology benefits from continuous input current. Despite the high voltage gain of proposed topology, it has considerably low normalised voltage stress (NVS) on its switches/diodes. Another important advantage of proposed topology is that, as the number of input units increase, the voltage gain increases too, but the NVS on switches/diodes decreases. The proposed topology is suggested for low and medium power applications. The 2-input version of proposed topology has been studied in detail and different operational modes and steady-state analyses have been presented. For a better evaluation, proposed topology has been compared with recently presented novel multi-input high step-up structures. The 2-input version has also been experimentally implemented. Obtained results confirm appropriate performance of proposed topology.

Summary In this paper, a simple non-isolated multiple input (MI) bidirectional DC-DC topology is proposed which can operate in buck, boost, or buck-boost modes. The proposed topology utilizes a battery pack to realize the bidirectional power flow operation especially when the input sources are non-storable ones. The excess energy of input sources can be stored in the battery and be injected to the load, when required. Simultaneous or independent power transfer of input sources is also provided. For better evaluation, the proposed topology has been compared with several recently presented novel topologies, from view point of number of inductors, capacitors, switches, and diodes. Comparison results show that the proposed topology utilizes less number of components (switches, inductors, capacitors, and current sensors) which can reduce the size, cost, and complexity of converter. Different operational modes of the proposed topology (unidirectional buck, boost, buck-boost modes, and bidirectional mode) have been presented. Also, boost mode of the proposed topology has been investigated in detail, from design point of view, and generalized relationships have been proposed for calculation of critical inductance (CI) and output voltage ripple (OVR) of proposed n-input boost topology. To validate proposed theoretical concepts, the proposed topology has been modeled and simulated in PSCAD/EMTDC software, and the 3-input boost version has been experimentally implemented. Simulation and experimental results confirm appropriate performance of the proposed topology.

In this paper, a developed single-phase basic 17-level inverter topology has been proposed that is based on Switched-Capacitor Cell (SCC). The proposed basic topology consists of a main unit and two SCCs. The proposed basic unit can be extended by increasing the number of SCCs on both sides of main unit that leads to entirely symmetric extended topology. Reduced device (DC source, switch, capacitor and, diode) count is the main advantage of proposed topology that results in less size, weight and cost. Application of two half-bridges instead of one full-bridge leads to less total standing voltage on the switches. Self-voltage balancing of capacitors, lesser cost function as well as high step-up capability is another main merits of proposed topology. Note that the self-voltage balancing property of capacitors discards the need for an extra complicated voltage regulation controller circuitry. Also, the proposed topology can successfully supply low power factor (R-L) loads. Simulations have been done in PSCAD/EMTDC software to verify the performance of proposed topology. The comparison and simulation results prove the superiority of proposed topology.

This paper proposes a new 11-level high step-up switched-capacitor based inverter topology. The suggested topology uses only one DC source and can produce a gain of 5. Also it can produce high ratios of steps per switches, gate driver circuits and DC sources, which leads to less devices, less volume, weight and expense. The Total Harmonic Distortion (THD) of produced voltage is low. So, the size of output filter can be reduced. Also, the suggested structure can be well applied on supplying low power factor $R-L$ loads. Natural voltage balancing of capacitors is another main merit of suggested structure that results in simple and easy control strategy. The suggested configuration has been introduced and its operational modes have been explained. Then it has been compared with novel similar topologies and simulated in MATLAB-SIMULINK. The comparison and simulation results confirm the appropriate features and proper operation of suggested configuration.

In this paper, two new switched-capacitor based 5 and 9-level inverter topologies have been suggested. Simple structure, natural voltage balancing of capacitors (easy control strategy), low voltage stress on switches as well as step-up capability (proposed 9-level topology) are the main merits of suggested topologies. Also based on comparison results, the suggested topologies utilize decreased devices (switches, gate driver circuits, diodes and capacitors) for producing the same count of levels. The suggested topologies can effectively supply the $R-L$ loads. The simulation results obtained from PSCAD/EMTDC software validates the effectiveness and correct operation of suggested structures.

A new step-up Cascaded Multi-Level Inverter (CMLI) has been proposed in this paper. The proposed basic 35-level topology is composed of 4 DC sources, 2 capacitors, 2 diodes and 12 switches. The sum of input DC sources is 10V dc , where the peak output voltage is 17V dc . So, the proposed basic topology can act a step-up inverter with the gain of about 1.7. The proposed basic topology has simple structure. Since the voltage balancing of capacitors are done naturally, the control of proposed topology is also simple. The number of levels per number of components (such as DC sources, switches, gate driver circuits, diodes and capacitors) in proposed basic topology is higher than other similar converters. In this paper, the proposed basic topology has been introduced and its operational principles have been presented. Then, it has been compared with recently presented novel structures. The comparison results validate the advantages of proposed basic topology. Then, the proposed basic topology has been extended to act as a Multi-Level inverter. Finally, the appropriate performance of proposed basic topology has been verified by simulation results, extracted from PSCAD/EMTDC software.

This paper proposes a double-input high voltage gain topology for Non-Isolated Non-Coupled Inductor (NINCI) based de-de converters. The proposed topology is capable of producing high voltage gains, while the Normalized Voltage Stress (NVS) on the switches/diodes remain low. Simple structure, continuous input currents and also the low current ripple of input sources are the advantages of proposed topology. The low/medium power applications are suggested for the proposed topology. In this paper, different operational modes and also steady state analyses of proposed topology have been presented. To verify effectiveness of proposed topology, it has been modeled and simulated in PSCAD/EMTDC software. Simulation results validate efficient performance and suitability of proposed topology.

A 15-level flying capacitor multi-cell based inverter with new control method is proposed. The main benefit of this topology is minimising the number of components (switches, insulated-gate bipolar transistor (IGBTs), diodes, flying capacitors and DC sources with minimum variety number) that are used for producing the same number of output voltage levels. The proposed novel control strategy is capable of regulating voltage of flying capacitors on desired values, which results in increased number of output voltage levels. Another feature of the proposed control strategy is robustness against the load changes. Moreover, a new algorithm is presented for determining the voltage rating of flying capacitors. Simulations carried out in PSCAD/EMTDC software package and the experimental data were validated against numerical results.

In this paper, an improved Non-Isolated bidirectional Multiple-Input (MI) Buck dc-dc converter has been proposed. In the proposed topology, the input sources can simultaneously/independently transfer energy to the load. The applied energy storage system -battery- not only realizes the bidirectional power flow (even when none storable input sources like Fuel Cells are utilized), but also can absorb the excess energy produced by input sources. Simple structure and reduced number of components (switches, inductors, capacitors and current sensors) are the main advantages of the proposed topology. Different operational modes and design consideration of proposed converter have been investigated. To confirm the validity of proposed converter, the two-input version has been modeled and simulated in PSCAD/EMTDC software and implemented experimentally. Obtained results validate the suitable performance of proposed topology.

In this paper, an improved Cascaded Multi-Level Inverter (CMLI) topology which can be "symmetric" or "asymmetric" is proposed. The improved topology can produce higher number of levels using lower number of components. Higher number of levels leads to generation of a high quality with low Total Harmonic Distortion (THD) output voltage waveform. To increase number of voltage levels, two algorithms are proposed for determination of magnitude of dc voltage sources, which are investigated and the most effective one is introduced. To verify operation of proposed topology, it is modeled and simulated in PSCAD/EMTDC software. Proper performance of proposed topology is confirmed by obtained simulation results.

In this paper, two types of DC-DC converters with modified structures and different control methods for generating AC output voltage are proposed. In the modified cascaded dual buck inverter, absence of split capacitors leads to increased reliability of the inverter. Also, a new structure is proposed for integrated dual buck-boost inverter. The proposed inverters are capable of obtaining maximum power from solar cells by themselves. To evaluate operations of the proposed inverters, they have been modeled and simulated in PSCAD/EMTDC for different modulation indexes. Simulation results confirm validity and effectiveness of the proposed inverters.