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In the standalone renewable energy system, a multiport converter is more desirable than several single-input converters as it has advantages of a simpler circuit, higher efficiency, and lower cost. This article proposes a novel topology synthesis method to derive integrated three-port converters with low cost and compact structure. With the proposed topology synthesis method, integrated three-port converters can be easily developed from conventional single-input single-output (SISO) converters by replacing a switch and a diode with a basic cell, including bidirectional power flow. Compared with the SISO converter, the derived integrated three-port converters only need to add the extra switch and diode, which makes them have low cost and compact structure. As an example, topology synthesis based on buck, boost, buck–boost, Cuk, SEPIC, and zeta converters is performed in this article. The proposed topology synthesis method can also be extended to deduce a series of n-port converters. In order to achieve a better understanding of the proposed converters, the integrated three-port SEPIC converter is specifically analyzed, including its operation principle, steady-state performance, small-signal modeling, and control system. Finally, experimental verifications have been carried out to illustrate the feasibility and effectiveness of the proposed topology synthesis method.

In this study, the integration of buck converter with Cuk converter to achieve a non-isolated high step-down dc–dc converter is investigated. Also, a soft-switching cell is modified and used in the integrated converter to provide zero current switching and zero voltage switching condition for the converter switches at turn-on and turn-off, respectively. The auxiliary cell also eliminates the reverse recovery problem of the converter diodes. As a result, a high efficiency high step-down converter with reduced voltage stress for semiconductor components is derived. The analysis, operational principle and design considerations of the proposed converter are discussed in this study. The accuracy of the converter operation is verified by a 200 W, 155 V-to-24 V laboratory prototype.

In this chapter, modeling of different DC–DC converter has been proposed. The execution investigation of different converters like Buck converter, CUK Converter, Buck–Boost Converter, Boost converter, Flyback and push–pull converters are also examined. The circuit of different converter has been designed in such a way that it delivers constant voltage as per the requirements. The different characteristics like output voltage, current, gain, etc. are also obtained with respect to the load. These characteristics of different DC–DC converter will definitely determine the improve nature of the voltage profile. These types of converters are used with different environmentally friendly power sources like solar energy, fuel cell, etc. The module of this type of converter can be connected with different distributed energy sources to get the flat voltage profile in presence of load. Basically, in this chapter various converters are connected with load in a stand-alone system, and the flat voltage profile has been obtained irrespective of the load with different converter circuit individually. An essential DC–DC converter takes the current and goes it through an exchanging component that transforms the DC signal into an AC square wave signal. This wave is at that point goes through another channel and transforms it back into a DC sign of the necessary voltage. DC–DC converters come in non-disengaged and confined assortments. Disconnection is controlled by whether the information ground is associated with the yield ground. When utilizing a DC–DC converter, it is acceptable practice to ensure that the source giving capacity to the DC–DC converter can give enough capacity to record to the shortcoming. Proficiency for these converters is normally determined in bends, with top effectiveness accomplished at certain heap current. Effectiveness might be lower at lower power yields, where the measure of intensity needed to control the circuit is practically identical to the heap power. These converters utilize shut input circles to give a directed yield. Changes in burden current or info voltage can cause impermanent movements. Speed of control circle reaction gives a thought in the amount of time that requires for the buck converter to react to changing conditions and get the yield voltage in guideline. They can be worked at high frequencies, empowering them to be made little. Since some misfortune systems increment with recurrence, making them be less effective, for that some degree of compromise can be made among the size and effectiveness.

This work proposes a non-isolated single-switch dc-dc converter based on the integration of the classical buck and Cuk topologies using the graft technique. The resulting converter aggregates some interesting advantages, e.g., both the input current and the current through the output stage are continuous with low ripple. A qualitative and quantitative analysis of the Cuk-buck converter is derived, showing that the circuit is suitable for high step-down applications. Simulation results obtained with PSIM® software are presented and discussed to demonstrate the accuracy of the theoretical analysis.

In this paper, a detailed analysis is presented for the continuous conduction mode (CCM) operation of a double-input/double-output DC/DC converter (DIDOC), which consists of two H-bridge cells, a buck converter, and a zeta converter. The zeta converter is utilized by applying a non-interleaved switching pattern on the transistors of the circuit. Hence, a buck converter can be implemented by adopting a low-pass filter to the other H-bridge cell. The whole converter can be operated either in step-up or step-down conditions. The proposed converter is created based on DISO buck-boost topologies. Compared to the DISO buck-boost and buck converters, the converter provides positive output voltages, which is demanded in many applications. Reduction in the number of components is another benefit of utilizing this converter compared to cuk and SEPIC converters. Design and analyses of the circuit has been verified using MATLAB-Simulink software.

Multioutput converters with single input source are currently studied as an alternative to conventional dc–dc topologies in order to improve power density in low-power multiload applications. This paper reviews three different ways in which a boost topology can be customized to supply multiple outputs. The first way uses a charge-sharing approach using individual switches to distribute inductor energy to different capacitors. The second method of creating a multiport converter (MPC) combines two converters with similar front end to generate two outputs using only one controlled switch. Using this method, a boost converter can be combined with single–ended primary–inductor converter (SEPIC), Cuk, and current source converter topologies. The third method uses time multiplexing of switches to produce two regulated ports and is referred to as switched-boost action. This method uses relatively less number of switches and allows regulation and control of all the outputs. Practical utility of switched-boost action based MPC is reported in this paper. This switched-boost MPC is applied to a renewable power converter system to interface a solar panel, a battery, and home loads to produce a 12-V and a 48-V bus. The 12-V bus is interfaced to battery and capable of optimally charging the battery in constant current–constant voltage (CC-CV) mode. The converter is demonstrated to operate with solar panel as it supplies a 12-V battery and a 48-V load bus. When the solar power is not available, the converter automatically goes into a mode in which the 12-V battery supplies the loads on the 48-V bus.

A novel non-isolated DC-DC converter is proposed by combining quadratic boost converter with voltage multiplier cell. The proposed converter has low semiconductor device voltage stress and switch utilization factor is high. The superiority of the converter is voltage stress of the semiconductor devices depends on voltage multiplier (VM) cell. By increasing the VM cell the stresses across the devices reduce drastically. The proposed converter has same number of components compared to certain voltage lift converters taken for comparison. A detailed comparative study is made on the proposed converter with few voltage lift converters in the literature, conventional boost with VM cell and quadratic boost converter. A 40 W prototype is constructed with 12 V input voltage and 96 V output voltage to verify the performance and validate the theoretical analysis of the proposed converter. Keywords: High gain, Quadratic, Multiplier, Voltage stress, Efficiency

This paper presents the operation principle and benefits of a novel power converter topology named three-level two-stage decoupled active neutral point clamped (3L-TDANPC) converter, which is implemented based on a hybrid utilization of silicon (Si) insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) metal–oxide semiconductor field-effect transistors ( mosfet s). The 3L-TDANPC converter can achieve high efficiency with limited number of SiC mosfet modules while keeping balanced loss distribution among the switching devices, which helps increase the converter power ratings. In addition, in this 3L-TDANPC converter, the SiC mosfet has a potential to ride through short-circuit fault because of the presence of Si IGBTs. The key challenges that are associated with system resonant current are investigated and the methods to damp such resonant current are proposed and explained in detail. The simulation and experimental results based on a 1-MW 3L-TDANPC converter prototype confirm the expected benefits of this proposed converter and the effectiveness of the proposed resonant current damping methods.

A 30-MHz voltage-mode buck converter using a delay-line-based pulse-width-modulation controller is proposed in this brief. Two voltage-to-delay cells are used to convert the voltage difference to delay-time difference. A charge pump is used to charge or discharge the loop filter, depending on whether the feedback voltage is larger or smaller than the reference voltage. A delay-line-based voltage-to-duty-cycle (V2D) controller is used to replace the classical ramp-comparator-based V2D controller to achieve wide duty cycle. A type-II compensator is implemented in this design with a capacitor and resistor in the loop filter. The prototype buck converter was fabricated using a 0.18- ${\mu }\text{m}$ CMOS process. It occupies an active area of 0.834 mm2 including the testing PADs. The tunable duty cycle ranges from 11.9%–86.3%, corresponding to 0.4 V–2.8 V output voltage with 3.3 V input. With a step of 400 mA in the load current, the settling time is around 3 ${\mu }\text{s}$ . The peak efficiency is as high as 90.2% with 2.4 V output and the maximum load current is 800 mA.

The primary objective of this review is to choose a DC–DC converter among the different converters used in solar system and to verify its reliability in the PV-based micro grid environment. As the requirement of energy is increasing day by day and the alternate endless source is solar energy, it is now the prime time for focusing on its feasibility, utility, and efficiency. In this process, we have studied the different subsections of the photovoltaic (PV) solar energy system such as DC–DC converter, Maximum power point tracker, pulse width modulation, filters, three-phase inverter, etc. The conclusion obtained is that the maximum power can be tracked efficiently with the P&O algorithm. Furthermore, to control and switch the DC–DC converts, Pulse Width Modulation (PWM) was performing satisfactorily. Still another issue is there to choose a suitable DC–DC converter among the several converters available and proposed in the literature. In this paper, the different DC–DC converters such as Buck, Boost, Buck-Boost, Cuk, and SEPIC are modeled in MATLAB and connected individually with a micro grid. To examine the behavior of the converters, the solar PV array is tested under various irradiations and temperature and results are recorded for verification. The paper is concluding that the CUK converter is providing maximum efficiency for steady-state output and providing a solution to the noise and unnecessary heating related to the DC–DC converter.

This paper presents the comparative analysis of various types of DC-DC converters using DC output voltage and the THD at the output side. The analysis is made in a standalone PV power system having the source and the load as two constants. The analysis basically involves the Buck-Boost Converter, Buck Converter, Boost converter, Zeta converter, and the Cuk converter. The harmonics present in the VSC output and the output of the DC converter at the same input basically decides the power quality produced by using the particular converter.

Digital to digital converters are methods for power transformation. They move a DC voltage level to another level dependent on the prerequisite. The fundamental circuit utilized for a DC/DC converter is one which is used to regulate the switching actions. This type of circuit is mainly responsible for relocating the energy from input terminal to the output terminal using various components like diodes, inductors, electronic switches etc. They are capable of stepping-up, stepping-down and inverting a given voltage parameter. The components which constitutes this regulating circuit can be arranged in different configurations to achieve desired outputs like that of step-down converters, step-up converters etc. The operating voltage requirement of various electronic devices, for example, Integrated Circuits (ICs) can vary over a broad range, making it mandatory to supply a particular voltage for each device. A DC/DC converter makes modification to the input DC voltage from a source into another DC voltage which is given as output. The Buck Converter yields a voltage lower than provided, while converse is the case with a Boost converter. This research article sees the comparison of DC/DC Converter using passive inductor with the one using active inductor. Switched mode DC–DC converter makes modification to the voltage level value by hoarding the energy either in form of magnetic field or electric field from input source for some temporary amount of time and then emancipating that stored energy at another voltage level. Whatever output voltage is received at the output terminal, it is exploited to match the power requirement of the load. These converters are mainly used in the vehicles, chargers and Video players.

The engineering design process is comprised of several major steps: 1. Specifications and other design goals are defined. 2. A circuit is proposed. This is a creative process that draws on the physical insight and experience of the engineer. 3. The circuit is modeled. The converter power stage is modeled as described in Chapter 7. Components and other portions of the system are modeled as appropriate, often with vendor-supplied data. 4. Design-oriented analysis of the circuit is performed. This involves development of equations that allow element values to be chosen such that specifications and design goals are met. In addition, it may be necessary for the engineer to gain additional understanding and physical insight into the circuit behavior, so that the design can be improved by adding elements to the circuit or by changing circuit connections. 5. Model verification. Predictions of the model are compared to a laboratory prototype, under nominal operating conditions. The model is refined as necessary, so that the model predictions agree with laboratory measurements. 6. Worst-case analysis (or other reliability and production yield analysis) of the circuit is performed. This involves quantitative evaluation of the model performance, to judge whether specifications are met under all conditions. Computer simulation is well-suited to this task. 7. Iteration. The above steps are repeated to improve the design until the worst-case behavior meets specifications, or until the reliability and production yield are acceptably high.

Maximum Power Point Tracking (MPPT) is a method that can be used to optimize the electrical power output from solar panels. The performance of the MPPT method on solar panel systems can be influenced by many variables. One of them is the selection of a DC-DC power converter. DC-DC-DC Converter is a component that is used to optimize the performance of solar panels. Several types of DC-DC Converter are Buck, Buck-Boost, Single Ended Primary Inductance Converter (SEPIC), and CUK. Each converter has a different effect on solar panels output power. In order to observe and make a comprehensive analysis, simulations are performed through PSIM (Power Simulator) software on the performance of several DC-DC Converters that use Flower Pollination Algorithm (FPA) as the MPPT algorithm. Variables that observed are the output power characteristic, the response of the voltage-current ripple signal, and the accuracy of the converter in the process of reaching the maximum power point condition. As a result, CUK converter can obtain the highest value of solar panel output power, 145.02 W. A low ripple level with a stable power value response is entirely generated by CUK and SEPIC Converter. Overall, for this system, the CUK converter has better performance than the other converters.

The multilevel dc-dc boost converter (MBC) is well known for its simple circuit structure and high voltage gain. Several controllers have been previously employed for their output voltage regulation. However, due to the non-minimum phase nature of the MBC, these controllers use both the inductor current and output voltage as feedback variables. This increases the complexity of the controller design and cost of implementation. In order to overcome these drawbacks, a voltage-mode controller for the regulation of the MBC is proposed in this brief. By using the generalized reduced-order state-space model of the converter and frequency-domain techniques, the stability of the voltage-controlled converter system is analyzed. In addition, some simulation and experimental results illustrating the ability of the proposed controller to regulate a $3{x}$ dc-dc multilevel boost converter in the presence of load and line voltage variations are provided.

Peak current mode (PCM) control has been widely used for the control of switching dc–dc converters due to its excellent transient performance. With the development of single-inductor dual-output (SIDO) dc–dc converters, PCM control technique is introduced to the control of SIDO dc–dc converters. Conventional PCM buck converter has only one reference current, with two inductor current borderlines are used to divide the operation modes of inductor current. However, PCM SIDO buck converter has more inductor current borderlines as it has one more reference current than that of PCM buck converter. In this paper, inductor current borderlines of PCM SIDO buck converter are investigated, and unified discrete iterative model of PCM SIDO buck converter is established. The effect of the difference of reference currents, initial inductor current and input voltage on the stability of PCM SIDO buck converter has been discussed by using bifurcation diagrams. The study results show that the stability of PCM SIDO buck converter is sensitive to the difference of reference currents, initial inductor current and input voltage. The stability boundary of the difference of reference currents, stability region of initial inductor current, and stability boundary of input voltage are derived. Lyapunov exponent and experimental results are carried out to verify the theoretical analysis results.

A new resonant zero-current switching (ZCS) multi-input/multi-output (MIMO) converter is presented. The proposed converter routes power from every desired input port to every desired output port independently. Capability of bidirectional operation is also provided. All semiconductor devices operate under the soft-switching conditions independent from operating voltage and output power. Power budgeting for the inputs, individually voltage regulation for the outputs, and internal voltage balancing for the bidirectional ports are attained with few power-element count. The system is synthesized systematically based on a topology belonging to the family of switched-resonator converters (SwRCs). No transformer is utilized, and common ground exists between all ports. The concept of route matrix is developed to determine the power multiplexing paths. This method greatly simplifies the analysis, design, and control of the proposed system. Mathematical formulation based on route matrix is given in detail. Circuit analysis, design procedure, and five different designs along with simulation and experimental results are presented.

Generally, in wireless inductive power transfer (IPT) system, the power is processed through multiple power transfer stages and this leads to lower efficiency and higher cost of the system. Recent research shows that the use of a direct ac–ac converter in an IPT system compensates these limitations significantly. However, one of the major challenges of the IPT circuit with direct ac–ac converter is to achieve multiple control goals through a single converter. These include load power requirement, maintaining high-quality source current and achieving soft switching of inverter switches, etc. In the existing literatures, the research is more focused on meeting load power requirement and soft switching of inverter switches. The major focus of this paper is to propose, analyze, and control a new IPT power converter topology using current-fed direct ac–ac converter. Compare with existing buck derived, i.e., voltage source ac–ac converter topologies, the proposed topology is boost derived; therefore, active source current waveshaping is easily obtained. The complete control is carried out through two loops, where the outer output current loop ensures load requirements and inner loop maintains the high-quality grid current. The detail of steady-state and dynamic analysis and design procedure of the converter is presented. Experimental results obtained from a 1.2-kW lab-build prototype are included to verify the analysis and proposed control.

The noninverting buck–boost converter has attracted significant attention in the photovoltaic (PV) module integrated application, as it offers high efficiency while maintaining a low cost and a simple topology. When this converter is employed, special care must be taken at the transition between buck and boost operating modes, as a dead-zone in the voltage transfer function can cause abrupt perturbations in the controlled voltage, decreasing the regulation quality and ultimately lowering the power conversion efficiency. In this paper, a new dead-zone compensation technique is proposed with the scope of smoothing the transition between operating modes, eliminating the voltage ripple and improving the regulation performance, while maintaining high efficiency. The converter under analysis is studied together with its gate driving circuit, which is based on a bootstrap capacitor power supply for the high-side switches. The proposed dead-zone compensation technique is deduced by using the principle of maintaining the ideal voltage gain function across the converter operating range. The technique is analyzed, implemented and tested on a purposely built PV module integrated noninverting buck–boost converter. The experiments reveal a sensible improvement of the voltage regulation during mode transition, confirming the effectiveness of the proposed technique and its fitness for the PV application.

This paper presents a high power density battery management system for electromobility applications that integrates voltage step-up and cell balancing functions inside a single converter topology. The presented system is based on assisting conversion concept, implemented with multiple dual-active bridge (DAB) converter modules. The assisting conversion, where the converter is only processing a portion of the output power proportional to the voltage difference between the battery pack and the output of the converter, allows for the use of a smaller converter than those of conventional systems. Also, at the system level, this type of conversion results in a higher power processing efficiency. The modular structure of the converter provides multiple connections to battery cells and allows on-line cell balancing during standstill, charging, and discharging of the battery pack. The operation of the system is regulated by a practical digital controller that performs cell balancing and, at the same time, regulates the output voltage. Experimental results obtained with a 24–48 V, 200-W, 100-KHz converter for small scooters demonstrate that the assisting converter is capable of providing the two previously mentioned functions while having a smaller volume and better power processing efficiency than both the conventional DAB and boost-based solutions. The assisting DAB converter runs at a peak efficiency of a 95.4% and processes only a maximum of a 66% of the output power.

This paper extends the trans-Z-source concept to ac–ac power conversion and proposes a novel single-phase trans-Z-source ac–ac converter. The proposed converter retains the advantages of its existing Z-source/quasi-Z-source counterparts in which the output voltage can be boosted and in-phase with the input voltage or bucked/boosted and out-of-phase with the input voltage. Meanwhile, a coupled inductor is introduced into the proposed converter, and the turns ratio of the coupled inductor become another control variable beside the duty cycle to obtain extreme voltage gain. Importantly, the input voltage and output voltage share the same ground, and the input current could be continuous, which is a benefit for reducing input current harmonics. Most important of all, the safe-commutation strategy for the proposed converter is deep developed, and analytic expression between the switches state and loop circuit voltage/current condition is derived out. Hence, the current/voltage ripple can be avoided without a loss snubber circuit, which benefits a reduced cost and enhanced reliability. The performance analysis is discussed in consideration of parasitic resistance, and system parameter design is optimized based on theoretic calculation. A laboratory prototype is fabricated, and experiments are performed to verify the validation of the proposed converter.

In this paper, a new single switch high step-up dc–dc converter with high voltage gain is proposed. The proposed topology is developed by combining boost and single-ended primary inductor converter with diode–capacitor circuit to reduce the stress across the semiconductor devices. The proposed converter produces low switching voltage and hence it improves its efficiency. The operating principle and the steady-state performance analysis are discussed. The performance of the converter is validated by developing a prototype circuit with input voltage of 30 V, output voltage of 300 V, and output power rating of 250 W. The theoretical analysis and experimental results conclude the proposed converter that is suitable for high-voltage applications.

A continuous-conduction mode (CCM) noninverting buck–boost (NBB) converter with a fast duty-cycle calculation (FDCC) control and duty-cycle locking strategy is proposed in this paper. Utilizing auxiliary and adjustable slopes of the modulation signal, the FDCC control not only rapidly determines an accurate duty cycle but also keeps the compensator output constant when the input voltage changes. The theoretical dc value of the numerator of the closed-loop line-to-output voltage transfer function is equal to zero whether the CCM NBB converter operates in boost or buck mode. It indicates that adopting the FDCC control can achieve ideal feedforward compensation for CCM buck and boost operations. Consequently, the output transient ripple of the CCM NBB converter with FDCC control can be eliminated significantly regardless of the unit-gain bandwidth of the NBB converter. To alleviate pulse skipping and to avoid changing buck and boost modes frequently, a duty-cycle locking method is adopted in the transition region of the buck and the boost. Hence, the duty-cycle locking method enhances power conversion and maintains the output voltage. The experimental results demonstrate that the proposed control schemes not only effectively reduce the line transient ripple but also obtain high efficiency in a wide range of input voltage.

Z-source networks are recently being employed to enhance the boosting capability of matrix converters. This paper concentrates on cascaded Z-source ultrasparse matrix converter (ZSUSMC), where the Z-source network is placed between the three-switch input rectifier stage and the six-switch output inverter stage. Two space vector modulation schemes, with and without a zero state in the rectifier stage modulation, are presented and their advantages and disadvantages are discussed. In addition, restrictions imposed on the converter operation in buck mode, which arise from unidirectional nature of the ultrasparse matrix converter, are discussed and a solution is proposed for offsetting those limitations. Furthermore, an optimal switching pattern, which results in minimum possible number of changes in the switching states as well as even distribution of the shoot-through state over the entire control period, is proposed. Also, common-mode voltages of the converter in all possible switching configurations are calculated. Hardware-in-the-loop studies of a ZSUSMC-based permanent magnet synchronous motor drive are carried out to evaluate the performance of the drive under the proposed modulation techniques. The obtained results are compared with a recent study and the superiority of the proposed method in terms of converter input/output current quality is demonstrated.

This paper presents an integrated boost converter having very low output voltage ripple making it suitable for analog applications, which are sensitive to supply noise. Architecturally, the converter consists of a conventional boost converter followed by an L–C filter, which drastically reduces the output ripple. The L–C filter has been realized using 30-nH bondwire inductance and 0.54-nF on-chip capacitance. The converter switches at 118 MHz and produces a regulated 3.2-V output from an input voltage ranging from 1.0 to 2.7 V. The converter is able to deliver up to 65-mA current for input voltage $\geq$ 2.4 V. The prototype has been implemented in 0.18- $\mu$ m standard digital CMOS process and the entire design consumes only 0.52-mm $^2$ chip area resulting in a maximum power density of 0.387 W/mm $^2$ . Peak efficiency of the converter is 77.4% at 32.2-mA current for 2.7-V input supply. The measured maximum output ripple noise is 21 mV that is less than 0.65% of the regulated output voltage.

A switched-capacitor-based dual-switch dc–dc converter with a high-boost voltage gain is proposed in this paper. The proposed converter can obtain a high-voltage gain with a small duty cycle, which decreases the voltage stress and the conduction loss on the power switches. This paper presents the key waveforms, the operating principles at the continuous conduction mode and the discontinuous conduction mode, and the parameter design. Moreover, a comparison between the proposed converter and other nonisolated converters has been completed. To verify the operating principle, a 200 W prototype is constructed with an input voltage of 25–50 V and an output voltage of 200 V. The simulation and experimental results are shown.

In this paper, an interleaved switched-capacitor bidirectional dc-dc converter with a high step-up/step-down voltage gain is proposed. The interleaved structure is adopted in the low-voltage side of this converter to reduce the ripple of the current through the low-voltage side, and the series-connected structure is adopted in the high-voltage side to achieve the high step-up/step-down voltage gain. In addition, the bidirectional synchronous rectification operations are carried out without requiring any extra hardware, and the efficiency of the converter is improved. Furthermore, the operating principles, voltage and current stresses, and current ripple characteristics of the converter are analyzed. Finally, a 1 kW prototype has been developed which verifies a wide voltage-gain range of this converter between the variable low-voltage side (50–120 V) and the constant high-voltage side (400 V). The maximum efficiency of the converter is 95.21% in the step-up mode and 95.30% in the step-down mode. The experimental results also validate the feasibility and the effectiveness of the proposed topology.

This study proposes a bidirectional grid-connected single-power-conversion converter with low-input battery voltage. The proposed bidirectional converter consists of a bidirectional dc–dc converter and an unfolding bridge, and the power conversion stage only corresponds to a bidirectional dc–dc converter. The bidirectional dc-dc converter can perform bidirectional power conversion between the low input battery voltage and a rectified sine wave due to its step-up/down voltage regulation functions. The unfolding bridge unfolds the rectified sine wave into the grid voltage and provides a current path to the grid. The study also proposes a control algorithm to regulate the grid current through a single power-processing stage. The control algorithm is comprised of a feed-forward nominal voltage compensator and a repetitive control scheme. The feed-forward nominal voltage compensator presets the operating point to lighten the burden of the grid current control, and the repetitive controller provides precise control of the grid current. Thus, the proposed bidirectional grid-connected single-power-conversion converter results in high power quality and high efficiency. Experimental results based on a 250-W prototype module are conducted to evaluate the performance of the converter and to verify the analysis.

The nine-switch converter is a multiport converter having two three-phase terminals and a dc-link, just like a 12-switch back-to-back (BTB) converter, but with 25% reduction of active switch count. However, the reduction from 12-switch to 9-switch may not always be an efficient choice considering losses in the switches. Only the load–source combination for the ac–ac common frequency mode and the source–source combination for the ac–dc different frequency (ac–dc DF) mode have been reported, so far, to yield relatively lower loss for the nine-switch converter. This paper shows that the nine-switch converter can have relatively lower loss even with a load–source combination, instead of only source–source combination in its ac–dc DF mode—when the upper terminal is connected to a dc load and the lower terminal is connected to an ac source. Mathematical proof is presented with derivation of the particular operating parameters for which the nine-switch converter will have comparatively lower losses. The analysis is validated with simulation and experimental results of a 1-kW system. Finally, the benchmark of the application criteria of the nine-switch converter for having lower conduction loss than the BTB converter is updated in this paper.

The noninverting synchronous buck-boost converter is preferable to operate in buck and boost operating modes to obtain a high operating efficiency. However, the dead zone, which degrades the performance of the converter, will occur when the converter shifts from buck operating mode to boost operating mode or vice versa. Therefore, the origin of the dead zone is derived in this paper by analyzing the relationship between the voltage conversion ratio and the duty cycles of the switches. Based on this, a series of three-mode and four-mode modulation schemes are systematically derived to completely eliminate the dead zone. The ripple and average value of the inductor current under different modulation schemes are investigated to evaluate the performance of these modulation schemes. To demonstrate the effectiveness of the proposed modulation schemes, two implementations of a four-mode modulation scheme are presented and experimentally tested as the examples for all modulation schemes. Experimental results correspond well with the theoretical analysis in both implementations over the entire input voltage range.

© 2017 IEEE. A novel non-isolated three-port converter (NITPC) is introduced in this brief. The purpose of this topology is to integrate a regenerative load such as DC bus and motor with dynamic braking, instead of the widely reported consuming load, with a photovoltaic (PV)-battery system. Conventional methods require either a separate DC-DC converter to process the reversible power flow or employing an isolated three-port converter (TPC), which allows bi-directional power flow between any two ports. However, these methods require many switches, which increases the converter size and control complexity. This brief hence presents a compact but fully functional design by combining and integrating basic converters to form a simplified single-inductor converter structure while keeping a minimum amount of switches. The resultant converter is fully reconfigurable that all possible power flow combinations among the sources and load are achieved through different switching patterns, while preserving the single power processing feature of TPC. This brief presents a design example of the proposed NITPC for a PV-battery powered DC microgrid. Detailed circuitry analysis, operation principles of both DC grid-connected and islanded modes, and experimental results of different modes in steady state and mode transitions are presented.

This paper describes the development of a new buck cascaded buck–boost power factor correction (PFC) converter of 2 kW with a soft-switching technique. For its wide range of input voltage, it operates in both buck and boost modes. The parameters are properly selected to endure voltage and current stress in all operating ranges. In addition, the electromagnetic interference (EMI) filter is used to reduce the EMI noise and guarantee continuous input current in buck operation. Moreover, the zero-voltage-transient pulse-width-modulation (ZVT-PWM) method is applied to improve the overall efficiency of the converter. The performance of the proposed PFC converter with the widest range of input voltage is evaluated by the hardware experimental test including harmonics analysis based on the International Electrotechnical Commission standard in all operating ranges. Also, the variations of power factor are theoretically analyzed in both buck and boost modes to determine the widest input range of the proposed PFC converter of 2 kW with an EMI filter. These are strongly required to commercialize it in practice. Finally, the efficiency of proposed PFC converter is compared with that of a conventional buck cascaded buck–boost PFC converter under various conditions.

Inherent disadvantages of conventional switched-capacitor converters (SCCs) are their discrete conversion ratio and inefficient energy transfer. To overcome these downsides, a switched-capacitor quasi-resonant pulsewidth-modulated converter is proposed. The operation stages and steady-state characteristics are described. Besides the theoretical analysis, experimental results for a step-up SCC are presented. The efficiency of this 100-W converter varies between 87% and 96% over a 30–40 V input voltage range with the output voltage between 80 and 160 V.

In this paper, a nonisolated dc–dc converter with high voltage gain is presented. Three diodes, three capacitors, an inductor, and a coupled inductor are employed in the presented converter. Since the inductor is connected to the input, the low input current ripple is achieved, which is important for tracking maximum power point of photovoltaic panels. The voltage stress across switch S is clamped by diode D 1 and capacitor C 1. Therefore, a main switch with low on-resistance RDS (on) can be employed to reduce the conduction loss. Besides, the main switch is turned on under zero current. This reduces the switching loss. The steady-state analysis of the proposed converter is discussed in this paper. Finally, the proposed converter prototype circuit is implemented to justify the validity of the analysis.

This study develops a newly designed, patented, bidirectional dc/dc converter (BDC) that interfaces a main energy storage (ES1), an auxiliary energy storage (ES2), and dc-bus of different voltage levels, for application in hybrid electric vehicle systems. The proposed converter can operate in a step-up mode (i.e., low-voltage dual-source-powering mode) and a step-down (i.e., high-voltage dc-link energy-regenerating mode), both with bidirectional power flow control. In addition, the model can independently control power flow between any two low-voltage sources (i.e., low-voltage dual-source buck/boost mode). Herein, the circuit configuration, operation, steady state analysis, and closed-loop control of the proposed BDC are discussed according to its three modes of power transfer. Moreover, the simulation and experimental results for a 1-kW prototype system are provided to validate the proposed converter.

A “one-and-a-half stage” forward-flyback converter for electrolytic capacitor-less light-emitting diode (LED) driver with high power factor (PF), high efficiency, low output ripple current, and long lifetime has been proposed and studied in this paper. The basic topology of the proposed topology is a single-switch forward-flyback converter for achieving high PF. In addition, a buck converter is inserted between the forward subconverter and the load for creating two paralleled power transfer paths. The most of input energy directly reaches the load through flyback subconverter, and only about 1/4 of total energy is transferred to the load through forward subconverter and buck converter. Therefore, the proposed topology is a “one-and-a-half stage” converter and can achieve higher efficiency than the traditional two-stage topologies. At the same time, power decoupling can be realized and the electrolytic capacitor can be eliminated. Optimal control scheme, detailed analysis, and design considerations for this improved converter are presented. Finally, an experimental prototype for 28 V/700 mA LED driver was built up to verify the theoretical analysis.

In this paper, a new nonisolated interleaved dc–dc converter with ultrahigh step down conversion ratio is proposed. The proposed converter has several main advantages such as extremely low voltage gain, extended duty cycle, automatic current sharing, low voltage and current stress on active switches, and low output current ripple. To achieve these advantages, several techniques are combined. The interleaved method is applied to reduce the current stress and decrease the output current ripple due to the phase shift between two modules. The series capacitors are used to improve the step down conversion ratio and clamp the voltage stress across the active switches due to the capacitive voltage division characteristic. Thus, the conduction losses of the proposed converter are reduced because of using MOSFET s with lower voltage rating. In addition, the coupled inductors are used to reduce the voltage gain and extend the duty cycle without imposing extra voltage stress across the active switches. Hence, the overall efficiency of the proposed converter is improved. A prototype of the proposed converter is implemented to verify the converter operation and the theoretical analysis.

A sub-1-μs ultrafast-response buck converter utilizing improved analog-voltage-dynamic-estimation (AVDE) techniques is proposed in this letter to improve previous works. First, the improved AVDE controller uses a new pseudocurrent circuit and a new ramp generator to get low gain, wide bandwidth, wide dynamic range, and low equivalent series resistor $(R_{{\text{ESR}}})$ . Second, the proposed converter has high performance, fast transient response, and low output voltage ripple. Third, the circuit does not need slope compensation so that it is very simple to implement. The switching frequency of the proposed buck converter is 1 MHz for nominal 3.3-V input and 0.8–2.5-V output range application. The experimental results prove that the proposed scheme improves the transient response within 1.2 μs and its maximum power efficiency can be up to 91.9%. The fastest transient time of the proposed converter is only 0.8 μs as the switching frequency is equal to 1 MHz. The settling time of the proposed converter is only within 0.8 cycle of the switching frequency. The maximum load current is 300 mA. The proposed buck converter has been fabricated with a commercial 0.35-μm CMOS 2P4M process, and the total chip area is about ${1.46 \;\text{mm}\times 1.5}$ mm, including PADs.

This paper proposes a new bidirectional direct pulse width modulation (PWM) three-phase buck-boost ac–ac converter. It requires six switches and three inductors and can provide wide range buck-boost voltage operation. It has high reliability due to no short-circuit and open-circuit risks in the converter. Therefore, it solves the commutation problem without using lossy snubber circuits, soft commutation strategies, and coupled inductors. It can be designed with metal–oxide–semiconductor field-effect transistors (MOSFETs) without their body diodes conducting, which eliminate reverse recovery issues and losses of body diodes. In addition, to reduce the ripples in input and output voltages and currents, the proposed converter can be operated with a PWM strategy-II. The PWM strategy-II is a type of interleaved PWM strategy with dead- and overlap-times operating modes. To validate the effectiveness of the proposed converter extensive analysis followed by detailed experimental results are provided.

This paper documents a new three-switch, isolated boost dc–dc converter. The major features of the proposed converter are as follows: 1) continuous input current; 2) reduced one active switch, one additional diode, and one additional capacitor; 3) unchanged primary and secondary voltage waveforms of the transformer when the duty cycle is changed; and 4) removal of the snubber circuit. This paper presents the operating principles, analysis, parameter design guidelines, and simulation results for the proposed converter. To verify the performance of the proposed converter, a 400 W prototype was constructed with a 40–60 V dc input. A PID controller was used to maintain the dc output voltage at 400 V. The simulation and experimental results matched those of the theoretical analysis.