An integrated magnetic isolated two-inductor boost converter: analysis, design and experimentation

This paper presents an integrated magnetic isolated two-inductor boost converter. Patent pending: USPTO/Worldwide filing number 60/444821. All magnetic components are integrated into one magnetic assembly. Two inductor windings are intrinsically coupled to allow input current to increase only when both primary switches are closed. The operation principle, start-up, and protection mechanisms are detailed. A prototype converter has been built. Experimental and simulation results verify the analysis.     

A new high-power-factor three-phase AC-DC converter: analysis,design, and experimentation

This paper proposes a new high-power factor three-phase AC-DC power converter, which is composed of a line interphase transformer (LIT) and two three-phase diode rectifiers, followed by a pulsewidth modulation (PWM) DC-DC boost power converter. The active switch of the boost converter is gated at a constant frequency such that the AC input current is discontinuous. This procedure provides an input current shaping without the third, fifth and seventh harmonics. The currents that flow through the LIT and boost inductors have such a high-switching frequency that ferrite cores with a small size can be utilized. In addition, the output voltage is regulated by PWM to compensate for line voltage variations and load change. Theoretical analysis, design procedure and example, along with experimental results taken from a 6 kW laboratory prototype are given     

A double ZVS-PWM active-clamping forward converter: analysis,design, and experimentation

This paper presents an isolated DC-DC converter based on two ZVS-PWM active-clamping forward converters connected in series and coupled by a single high-frequency transformer. The proposed converter features no switching losses from no-load to full-load operation and low conduction losses. This converter is suitable for high input voltage (>400 VDC) and high power applications. Operation principles, theoretical analysis and design example, are presented, as well as experimental results taken from a 3 kW laboratory prototype     

A new family of ZVS-PWM active-clamping DC-to-DC boost converters:analysis, design, and experimentation

The purpose of this paper is to introduce a new family of zero-voltage switching (ZVS) pulse-width modulation (PWM) active-clamping DC-to-DC boost power converters. This technique presents ZVS commutation without additional voltage stress and a significant increase in the circulating reactive energy throughout the power converters. So, the efficiency and the power density become advantages when compared to the hard-switching boost power converter. Thus, these power converters may become very attractive in power factor correction applications. In this paper, the complete family of boost power converters is shown, and one particular circuit, taken as an example, is analyzed, simulated and experimented. Experimental results are presented, taken from a laboratory prototype rated at 1600 W, input voltage of 300 V, output voltage of 400 V, and operating at 100 kHz. The measured efficiency at full load was 98%, and the power converter kept an efficiency up to 95% from 17% to 100% of full load, without additional voltage and current stresses     

Buck quasi-resonant converter operating at constant frequency:analysis, design, and experimentation

A buck pulsewidth modulated zero-current switching quasi-resonant converter (buck PWM ZCS QRC) operating at constant frequency is discussed. Operating principle and design-oriented analysis are presented with normalized design curves, design procedure, design example, simulations, and experimental results. The new topology, which can be considered as a particular one, is compared with the well-established buck frequency-modulated zero-current switching quasi-resonant converter (buck FM ZCS QRC) proposed by Fred C. Lee (1988)     

Low-input-voltage, low-power boost converter design issues

Issues associated with boost converter design and performance are investigated when a low input voltage is used. Low-input-voltage sources include single fuel cells, single solar cells, and thermoelectric devices. The primary context is interfacing single micro fuel cells to portable electronic loads, such as mobile phones. Efficiency and circuit startup are the two most difficult issues for a low-cost design. It is shown in theory and experiment that the boost converter has a voltage collapse point. A simple startup technique is proposed that is appropriate for some applications.     

Design and analysis of power-CMOS-gate-based switched-capacitor boost DC-AC inverter

A multistage power CMOS-transmission-gate-based (CMOS-TG) quasi-switched-capacitor (QSC) boost DC-AC inverter is proposed and integrated with a boost DC-DC converter for a step-up application with AC or DC load. In this paper, using CMOS-TG as a bidirectional switch, the various topologies can be integrated in the same configuration for achieving two functions: boosting and alternating; boosting for getting a sinusoidal output in which the peak is the result of a many times step-up of the input; alternating to realize the positive/negative half sinusoidal of the output. The inverter does not require any inductive elements as inductor and transformer, so integrated circuit (IC) fabrication will be promising for realization. By using the state-space averaging technique, the large-signal state-space model of the inverter is proposed, and then both the static analysis and dynamic small-signal analysis are derived to form a unified formulation for inverter/converter. Based on this formulation, there are presented for theoretical analysis/control design, including steady-state power, conversion efficiency, voltage conversion ratio, output ripple percentage, capacitance selection, closed-loop control and stability, and total harmonic distortion (THD), etc. Finally, a six-stage QSC boost DC-AC inverter is simulated by PSPICE, and the simulations are discussed for some cases, including: 1) steady-state AC output, ripple percentage, and power efficiency; 2) transient response of the regulated inverter for load variation; 3) a practical capacitive load: electromagnetic luminescent (EL) lamp, and 4) efficiency, ripple percentage, and THD for different loads. The results are illustrated to show the efficacy of the proposed inverter.     

Fuzzy PI-type controller design for boost converter

We consider the fuzzy controller design problem for a boost DC-DC converter. We design a fuzzy PI-type controller based on the common control engineering knowledge that the transient control performance can be improved if we increase the P and I gains as the error grows. Using Kharitonov’s theorem, we derive a closed-loop control system stability condition which can be used to tune the fuzzy PI control parameters. Finally, we give simulation and experimental results to show the effectiveness and practicality of the proposed method.     

A fixed-frequency modified series-resonant converter: analysis,design, and experimental results

It is shown that a fixed-frequency modified (LCL-type) series-resonant converter operates in five different modes with variations in the load current and the supply voltage. The converter is analyzed using the state-space approach for these operating modes. Both the general solutions and the steady-state solutions are obtained. Based on the analysis, design curves are obtained and a simple design procedure is illustrated using a design example. Detailed experimental results obtained from a MOSFET-based 500 W converter are presented to verify the analysis. It is shown that using a proper design, the converter operates only in modes 2 and 3, ensuring a lagging power factor mode of operation for very wide variations in the load and supply voltage     

A new, soft-switched, high-power-factor boost converter with IGBTs

A new soft-switching technique that improves performance of the high-power-factor boost rectifier by reducing switching losses is introduced. The losses are reduced by an active snubber which consists of an inductor, a capacitor, a rectifier, and an auxiliary switch. Since the boost switch turns off with zero current, this technique is well suited for implementations with insulated-gate bipolar transistors. The reverse-recovery-related losses of the rectifier are also reduced by the snubber inductor which is connected in series with the boost switch and the boost rectifier. In addition, the auxiliary switch operates with zero-voltage switching. A complete design procedure and extensive performance evaluation of the proposed active snubber using a 1.2 kW high-power-factor boost rectifier operating from a 90 V_rms-256 V_rms input are also presented     

A new technique for parallel connection of commutation cells:analysis, design, and experimentation

A new technique useful for the parallel connection of commutation cells is introduced in this paper. It consists of using small inductances in order to ensure dynamic and static sharing of the commutated current among the different switches. The operating principle, theoretical analysis and design procedure are presented. Experimental results, obtained from a 400-W buck power converter prototype using two commutation cells, have been used to validate the theoretical analysis and demonstrate the effectiveness of the proposed technique. Several experiments have been also accomplished to clear up the advantages of this new technique in comparison to the conventional one. Results from a three-cell buck DC-DC power converter delivering 4.5 kW are also presented, revealing a balanced current sharing among cells and an excellent dynamic behavior, as foreseen in the theoretical analysis     

A novel multicell DC-AC converter for applications in renewable energy systems

This paper presents a novel DC-AC converter for applications in the area of distributed energy generation systems, e.g., solar power systems, fuel-cell power systems in combination with supercapacitor or battery energy storage. The proposed converter is realized using an isolated multicell topology where the total AC output of the system is formed by series connection of several full-bridge converter stages. The DC links of the full bridges are supplied by individual DC-DC isolation stages which are arranged in parallel concerning the dc input of the. total system. Therefore, all switching cells of the proposed converter can be equipped with modern low-voltage high-current power MOSFETs, which results in an improved efficiency as compared to conventional isolated DC-AC converters. Furthermore, the cells are operated in an interleaved pulsewidth-modulation mode which, in connection with the low voltage level of each cell, significantly reduces the filtering effort on the AC output of the overall system. The paper describes the operating principle, analyzes the fundamental relationships which are relevant for component selection, and presents a specific circuit design. Finally, measurements taken from a 2-kW laboratory model are presented.     

Design-oriented analysis of boost zero-voltage-switching resonantDC/DC converter

Analysis and design procedures are presented for a high-efficiency, high-frequency, boost zero-voltage-switching resonant DC/DC power converter. Equations describing converter operation are derived. The basic performance parameters of the circuit are analyzed as functions of the normalized load resistance and switching frequency. These equations are then used to determine conditions for lossless converter operation and design equations that yield the required component values     

Steady-state analysis of an interleaved boost converter withcoupled inductors

Boost converters are widely used as power-factor corrected preregulators. In high-power applications, interleaved operation of two or more boost converters has been proposed to increase the output power and to reduce the output ripple. A major design criterion then is to ensure equal current sharing among the parallel converters. In this paper, a converter consisting of two interleaved and intercoupled boost converter cells is proposed and investigated. The boost converter cells have very good current sharing characteristics even in the presence of relatively large duty cycle mismatch. In addition, it can be designed to have small input current ripple and zero boost-rectifier reverse-recovery loss. The operating principle, steady-state analysis, and comparison with the conventional boost converter are presented. Simulation and experimental results are also given     

A zero-current-switched off-line quasi-resonant converter withreduced frequency range: analysis, design, and experimental results

A half-bridge zero-current-switched (ZCS) offline quasi-resonant converter (QCR) operating in full-wave mode is implemented to reduce the modulation frequency range due to load variations. The design and characteristics of the converter are described and compared with their half-wave counterpart in frequency range, component stress, and efficiency. An experimental converter which delivers output power from 10 to 100 W with a modulation frequency from 700 kHz to 1.4 MHz is presented. The converter showed superior transient response compared to the corresponding half-wave converter. The efficiency of the full-wave converter at full-load was several percent lower than that of the half-wave converter and decreases at a much faster rate as the output power decreases     

A novel tri-state boost converter with fast dynamics

A challenging problem in the design of boost converters operating in continuous-conduction mode is posed by the dynamically shifting right-half-plane (RHP) zero in the converter's small-signal control-to-output transfer function. The paper proposes a novel tri-state boost converter without such a zero in the transfer function. The additional degree of freedom introduced in the converter in the form of a freewheeling interval has been exploited through an easy control technique to achieve this elimination. The absence of the RHP zero allows the control scheme to achieve larger bandwidth under closed-loop conditions, resulting in fast response. Analytical, simulation and experimental results of the tri-state boost converter have been presented and compared with those of the classical boost converter both under open-loop and under closed-loop operating conditions. The results clearly demonstrate the superior dynamic performance of the proposed converter. The proposed converter can be used in applications wherever fast-response boost action is needed.     

Forward-flyback converter with current-doubler rectifier: analysis,design, and evaluation results

Complete design-oriented steady-state analysis of the forward-flyback converter, with the current-doubler rectifier is provided. Advantages and disadvantages of this topology compared to the conventional forward converter are discussed. In particular, the transformer-secondary copper losses are evaluated. In addition, a step-by-step design procedure is given, Finally, experimental evaluation results obtained on a 3.3 V/50 A DC/DC converter prototype for the 40-60 V input-voltage range are presented     

A continuous conduction mode low-ripple high-efficiency charge-pump boost converter

In this paper, a new continuous conduction mode (CCM) low-ripple high-efficiency charge-pump boost converter is presented. Its components include a double voltage charge pump and a low pass LC filter. The voltage boost ratio of the positive low-ripple output voltage of the proposed converter is (1 + D) where D is the duty cycle of the control switching signal waveform. Since the energy storage inductor is connected to the power source and the load at all times, the proposed converter always operates in CCM, the transient responses are fast, and the current stress on the output capacitor is reduced and the output voltage ripple is small. In this paper, the operation principles of the CCM low-ripple high-efficiency charge-pump boost converter are described in detail. Its circuitry is designed and implemented with a TSMC 0.35 μm CMOS processes whose operation frequency is 1 MHz. The circuitry is simple and the power conversion efficiency is up to 90.95 %, and the transient response is only 7 μs.     

A high-power-factor half-bridge doubler boost converter without commutation losses

This paper proposes a high-power-factor half-bridge doubler boost converter without commutation losses, which provides high output voltages, i.e., from 600 to 900 V. The voltages across the semiconductor devices are low and approximately equal to the output voltage, as doubled output voltages and reduced high-frequency ripple can be achieved. A detailed mathematical analysis concerning its operation is presented, and simulation and experimental results describe the converter performance.     

A unity power factor converter using half-bridge boost topology

A single-phase high-efficiency near-unity power-factor (PF) half-bridge boost converter circuit, which has been proposed earlier by other researchers, is presented with detailed analysis. This converter is capable of operating under variable PF. However, the focus of this paper is in achieving unity PF operation only. The efficiency of this circuit is high because there is only one series semiconductor on-state voltage drop at any instant. The existence of an imbalance in the voltages of the two DC-link capacitors, which was noted before, is confirmed here. The cause for the imbalance is analyzed using appropriate models, and a control method to eliminate it is discussed in detail. Analysis and design considerations for the power circuit using the fixed-band hysteresis current control (HCC) technique are provided. The analytical results are verified through simulation using switched and averaged circuit models of the scheme and also through experimental work. At 90-V AC input and 300-W 300-V output, the experimental prototype demonstrates an efficiency of 96.23% and a PF of 0.998. This converter, with its relatively high DC-output voltage, is well suited for the 110-V utility supply system. A circuit modification for universal input voltage range operation is also suggested