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 soft-switched PWM boost converter with a lossless auxiliary circuit

A soft-switching scheme for the PWM boost converter is newly proposed to obtain the desirable features of both the conventional PWM boost and resonant converters such as ease of control, reduced switching losses and stresses, and low EMI. In order to achieve the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft-switching for both the main switch and the output diode while not incurring any additional losses due to the auxiliary circuit itself. The basic operations, in this paper, are discussed and design guidelines are presented. Through a 100?KHz, 60?W prototype, the usefulness of the proposed scheme is verified.     

Analysis of a soft-switched PFC boost converter using analog and digital control circuits

This work presents a comparison between analog and digital (PIC16c73a) control types applied to the boost converter with a nondissipative snubber. Both control types use the bang-bang hysteresis current waveshaping control technique in order to achieve a quasi-unity power factor. The analog control applied presented a high power factor (0.998), high efficiency (92.87%), and low harmonic distortion [total harmonic distortion of current (THDI =2.84% and total harmonic distortion of current (THDV) =2.83%]. The digital control presented a high power factor (0.990), high efficiency (92.46%), and low harmonic distortion (THDI=5.09% and THDV=2.84%).     

A new soft-switched PFC boost rectifier with integrated flyback converter for stand-by power

This paper presents a magnetic integration approach that reduces the number of magnetic components in a power supply by integrating magnetic components in two conversion stages. Specifically, in the proposed approach, a single transformer is used to implement the continuous-conduction-mode boost power-factor-corrected (PFC) converter and the dc/dc flyback converter. The integrated boost and flyback converters offer soft switching of all semiconductor switches including a controlled di/dt turn-off rate of the boost rectifier. The performance of the proposed approach was evaluated on a 150-kHz, 450-W, universal-line range boost PFC converter with 12-V/2.2-A integrated stand-by flyback converter.     

A new three-level soft-switched converter

A three-level, constant-frequency, isolated converter which employs a coupled inductor to achieve zero-voltage switching of the primary switches in the entire line and load range is described. Because the coupled inductor does not appear as a series inductance in the load current path, it does not cause a loss of duty cycle or severe voltage ringing across the output rectifiers. The operation and performance of the proposed converter was verified on a 1-kW prototype.     

A soft-switched current-controlled converter for induction machinedrives

The paper proposes a current controlled inverter operating in zero voltage switching (ZVS) mode for an induction machine drive. Operation with no voltage stress in the DC link bus is achieved. Together with the soft switching operation, a fixed frequency bang-bang current control technique is also implemented to allow for an accurate shaping of sinusoidal currents to feed the motor. As a result, a ripple free torque profile in steady state operation is achieved. With the soft switching technique it is possible to operate conventional IGBTs at 40 kHz. A detailed analysis of the circuit operation is presented. The feasibility of the proposed scheme is experimentally verified on a prototype     

High-power-factor single-stage converter with robust controller foruniversal off-line applications

This paper presents a robust-controlled single-stage converter (SSC) operating either in discontinuous conduction mode (DCM) or in continuous conduction mode (CCM) to achieve high power factor for universal line voltage range from 90 to 264 V_rms. At light load, the proposed system is operated in the DCM, while at heavy load the system is operated in the CCM, thus, the DC-link voltage can be properly controlled within a certain voltage range and the efficiency can be improved as well. The overall system is with a robust controller and is operated in a fixed frequency. In the design, the load variation and line voltage variation are treated as plant uncertainty and control disturbance, respectively. The H^∞ robust control method is adopted to design a proper robust controller to achieve robust stability and robust performance. The measured results from a prototype have confirmed the effectiveness and feasibility of the proposed system     

A high-efficiency soft-switched AC/DC converter with current-doubler synchronous rectification

An improved ac/dc converter based on asymmetrical half-bridge topology is proposed in this paper. To substantially enhance the efficiency for low-voltage/high-current output applications, a current-doubler synchronous rectifier is combined with a modified asymmetrical half-bridge converter that retains the inherent zero-voltage-switching property. The power losses in the secondary rectification stage and the primary switches can be significantly reduced. The proposed architecture exhibits extreme simplicity and lower cost while providing unity power factor, well-regulated output, and high power density. The detailed operating principles and design procedures for the proposed converter are described in this paper. Simulation and experimental results for a laboratory prototype are discussed to verify the feasibility.     

Buck or boost tracking power converter

A cascade of buck and boost converter is presented here. The control operates in a manner that the converter is either in buck or boost (BOB) mode on a cycle by cycle basis. It transitions between the modes seamlessly to provide a tracking power conversion function for modulating the power supply of a variable envelope radio frequency (RF) power amplifier. The control algorithm and its implementation using switched capacitor circuits is described. Simulation and measured experimental results including converter efficiency, tracking accuracy, and spectrum at the output of the RF power amplifier are provided. This control technique allows seamless transition between the buck and boost modes while tracking RF envelopes with bandwidth greater than 100 kHz, and maintaining extreme accuracy and extremely low ripple. The efficiency of this converter operating at 1.68 MHz is close to 90% over a wide range of conversion ratios. The area of the power converter is extremely small allowing this to be integrated into a cellular telephone. The controller was integrated as part of a larger power management IC as well as a discrete IC.     

Robust nonlinear control for boost converter

The standard current loop is modified for a boost converter to eliminate sensitivity of the control-to-output transfer function to the nature, and magnitude of resistive load. An additional term directly proportional to the load current and output voltage, and inversely proportional to the input voltage is added to the current loop. This results in practically invariant loop gains for different resistive loads, including constant power load     

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.     

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.     

Control of chaos in the boost converter

A method for controlling chaos which is particularly suitable for switching circuits is presented. The method has been successfully applied to the current-mode controlled boost converter which is a piecewise linear system with switching nonlinearity     

ANALYSIS OF ZERO-VOLTAGE QUASI-RESONANT BOOST DC-DC CONVERTER

The zero-voltage quasi-resonant boost switching DC-DC converter has been inves-tigated by using the time averaging equivalent circuit approach of periodically switching linearnetworks.The DC steady state and AC small signal characteristics of the converter are also given.     

New two-inductor boost converter with auxiliary transformer

A new, two-inductor, two-switch boost converter topology and its variations suitable for applications with a large difference between the input and output voltage are described. The output voltage regulation of the proposed converters is achieved in a wide load and input-voltage range with constant-frequency control by employing an auxiliary transformer that couples the current paths of the two boost inductors.     

Non-isolated high-gain boost converter using voltage-stacking cell

A non-isolated high-gain boost converter using a voltage-stacking cell is proposed. The voltage gain can be increased by adjusting the number of voltage-stacking cells and the transformer turns-ratio. Test results with a 1 kW prototype converter show that voltage gain is three or four times higher than the conventional boost converter at the unity transformer turns-ratio and about 90% of efficiency is recorded under full load condition.     

Control of parallel-module boost converter with two-stage outputfilter

The authors demonstrate that the performance of parallel-module boost converters with two-stage output filters can be enhanced by employing additional feedback from the summing junction of the converter modules. The performance improvement is verified by both frequency- and time-domain simulations     

ZVT-PWM AC-DC boost converter with ZCS auxiliary circuit

A low conduction loss, low-cost zero-voltage-transition-pulsewidth modulation (ZVT-PWM) boost converter with a zero current switching (ZCS) auxiliary circuit is developed to achieve high-conversion-efficiency operation. The unique locations of the resonant capacitor and inductor ensure that low switching stress and commutation losses are obtained in this converter. It is very suitable for high power-factor-correction pre-regulators     

基于Boost变换器的光伏并网系统研究

分布式光伏发电并网系统通过多支路Boost变换器并联提高了供电质量,减小了每个模块的电应力,提高了系统的功率密度,实现了分布式电源系统的冗余,有利于标准化分布式电源系统,实验证明了并联Boost变换器在实际应用中的良好效果。     

Improved active power-factor-correction circuit using azero-voltage-switching boost converter

In this paper, a zero-voltage-switching (ZVS) scheme for a boost power converter is proposed and discussed. This lossless zero-voltage scheme is shown to improve the performance of active power factor correction circuits. The results are validated by both simulation and experimental results