Analysis,design and implementation of an interleaved three-level PWM DC/DC ZVS converter

This paper presents a new parallel three-level soft switching pulse-width modulation (PWM) converter. The proposed converter has two circuit cells operated by the interleaved PWM modulation. Thus, the ripple currents at input and output sides are reduced. Each circuit cell has two three-level zero voltage switching circuits sharing the same power switches. Therefore, the current and power rating of the secondary side components are reduced. Current double rectifier topology is selected on the secondary side to decrease output ripple current. The main advantages of the proposed converter are soft switching of power switches, low ripple current on the output side and low-voltage rating of power switches for medium-power applications. Finally, the performance of the proposed converter is verified by experiments with 1 kW prototype circuit.     

Interleaved ZVS Converter With Ripple-Current Cancellation

In this paper, an interleaved soft-switching converter with ripple-current cancellation is presented to achieve zero- voltage-switching (ZVS) turn-on and load current sharing. In order to achieve ZVS turn-on, an active snubber is connected in parallel with the primary winding of the transformer. The energy stored in the transformer leakage inductance and magnetizing inductance can be recovered so that the peak voltage stress of switching devices is limited. The resonance at the transition interval is used to realize ZVS turn-on of all switches. In order to achieve three-level pulsewidth-modulation (PWM) scheme, an addition fast-recovery diode is used in the converter. Three-level PWM scheme can reduce the ac ripple current on the output inductor such that the output inductor can be reduced. The current-doubler rectifier is adopted in the secondary side of the transformer to reduce the transformer secondary-winding current and output voltage ripple by canceling the current ripple of two output inductors. The output voltage is controlled at the desired value using the interleaved PWM scheme. These features make the proposed converter suitable for the dc-dc converter with high output current. The operation principles, steady state analysis, and design equations of the proposed converter are provided in detail. Finally, experiments based on a 600-W (12 V/50 A) prototype are provided to verify the effectiveness and feasibility of the proposed converter.     

一种新型交错并联同相降压升压DC/DC转换器

为了有效降低电流纹波和提高转换器效率,提出一种新型交错并联同相降压升压DC/DC转换器。提出的结构通过采用输入/输出（I/O）磁耦合交错并联和阻尼网络技术,降低了开关的电压应力、内部电压振荡和I/O电流纹波,并提升了转换器的效率。采用状态空间平均法,在连续导通模式下分析了提出转换器的稳态运行,从理论上证明了其优势。样机的功率设置为360W,输出电压为36 V,模拟结果以及实验结果显示,当输出电流为6A时,转换效率最高达到96%,最大输入电流纹波百分比仅为9.4%,相较于其他类似转换器,提出的转换器具有效率较高和I/O电流纹波较低的优势。     

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     

Interleaved soft switching resonant converter with a small input ripple current

ABSTRACT

An interleaved frequency control soft switching converter is studied for solar power or fuel cell power applications. The proposed circuit topology contains two parallel current-fed circuit cells with interleaved pulse-width modulation operation. Thus, the ripple currents at input and output terminals are decreased. In each circuit cell, the proposed current-fed dc-dc converter includes boost circuit and resonant circuit to achieve current ripple-free on low voltage side and less switching losses on active devices. The boost circuit and the resonant circuit have same active devices to decrease power switches. Due to the resonant behaviour, the reverse recovery current loss on secondary diodes is removed. The voltage doubler circuit topology is accomplished on secondary-side to reduce diode counts and conduction loss. The performance and effectiveness of the developed interleaved PWM current-fed converter are verified and confirmed by experiments.     

一种四相交错并联BoostDC／DC变换器的设计

通信电源及分布式电源主要由前级高频整流器、中间级电池组和后级DC／DC变换器组成。DC／DC变换器的输入部分通常采用大功率Boost变换器,以将前级与中间级的直流电压提升至一定的幅度,从而更方便地形成所需提供给负载的各种电压。IntelCPU广泛用于IT工业,其对电源的要求越来越严格,需要提供更低的电压、更大的电流及更快的动态响应。为了改进Buck类型电压调整模块（Voltage Regulator Module,简称VRM）的动态响应要求,广泛使用多相交错并联技术,以实现快速的动态响应且极大地降低输出电流纹波。文章以一个大功率的四相交错并联Boost变换器作为设计实例,详细说明了其工作原理及主要器件的设计与选用;论证了该项技术用于BoostDC／DC变换器的多种优点,从而证明了多相交错并联技术的先进性和实用性。     

用于改善PFC性能的交错式三电平变换器

在不增大输入电流纹波的前提下,为改善升压型功率因数校正变换器在高频状态下的输入电流过零畸变,同时减小电感体积,降低开关器件的电压电流应力,进而提高变换器的功率等级,提出了一种交错式三电平变换器拓扑。此拓扑将交错并联技术与三电平技术相结合,弥补了交错并联拓扑只能改善输入电流过零畸变,而无法提升变换器的其他性能的不足。分析了此变换器的原理及工作情况,并进行仿真,仿真结果验证了该拓扑的有效性。     

Passivity-Based Control for an Interleaved Current-Fed Full-Bridge Converter With a Wide Operating Range Using the Brayton–Moser Form

An interleaved current-fed full-bridge converter has the capability to step up the voltage while maintaining a low input current ripple. Therefore, it is suitable for application such as a front-end converter for fuel cell where the source current ripple has to be small. However, since the source voltage varies with change in load profile, it is a challenge to design a stable controller that works well for a wide operating range. In this paper, an energy-based approach using a Brayton–Moser modeled passivity-based controller is proposed along with an augmented integrator to achieve voltage regulation under wide operating range. Experimental results verify that the proposed controller is able to achieve good dynamic performance and stable operation under wide operating range.      

一种新型基于二次型Buck变换器的交错并联LED驱动电源

为了减小输出电流纹波,提出了一种基于二次型Buck变换器的交错并联LED驱动电源。主电路由一个二次型Buck变换器和一条新增支路构成,这条新增支路包括一个开关管、二极管、电感和电容,优化了原有的拓扑结构,实现了高功率因数和恒流输出。采用交错并联技术,有效减小了滤波电感和输出电流纹波,纹波大小仅为输出电流峰峰值的0.18%。最后通过实验样机详细验证了理论分析的正确性。     

Current balancing control for an interleaved boost power converter

The interleaved boost power converter has the advantages of ripple cancellation and better efficiency. The major problem of the interleaved boost power converter is the current balancing among different phases of the boost power converters. In this paper, a current balancing control method for equalizing the currents of two-phase interleaved boost power converter is proposed. The output current can effectively detect the mismatch between the boost power converters for the interleaved boost power converter. The output current is used to perform both the current balance and the current-mode control. The salient feature is that only one current sensor is used in the proposed current balancing control method. A hardware prototype is developed, and the experimental results verify the performance of the proposed current balancing control method is as expected.     

Analysis and Design of a Novel Three-Phase AC–DC Buck-Boost Converter

This paper proposes a novel three-phase ac-dc buck-boost converter. The proposed converter uses four active switches, which are driven by only one control signal. This converter is operated in discontinuous conduction mode (DCM) by using the pulsewidth modulation (PWM) technique, and the control scheme very easily and simply achieves purely sinusoidal input current, high power factor, low total harmonic distortion of the input current and step-up/down output voltage. Also, the proposed converter provides a constant average current to the output capacitor and load in each switching period. Thus, the ripple component of sixth times line frequency will not appear in the output voltage. Therefore, a smaller output capacitor can be used in the proposed converter. Moreover, the steady-state analysis of voltage gain and boundary operating condition are presented. Also, the selections of inductor, output capacitor and input filter are depicted. Finally, a prototype circuit with simple control logic is implemented to illustrate the theoretical analysis.     

Hybrid Full-Bridge Three-Level LLC Resonant Converter—A Novel DC–DC Converter Suitable for Fuel-Cell Power System

This paper proposes a novel hybrid full-bridge (H-FB) three-level (TL) LLC resonant converter. It integrates the advantages of the H-FB TL converter and the LLC resonant converter. It can operate under both three-level mode and two-level mode, so it is very suitable for wide-input-voltage-range applications, such as fuel-cell power systems. Compared with the traditional full-bridge converter, the input current ripple and output filter can be reduced. In addition, all the switches can realize zero-voltage switching from nearly zero to full load, and the switches of the TL leg sustain only half of the input voltage. Moreover, the rectifier diodes can achieve zero-current switching, and the voltage stress across them can be minimized to the output voltage. A prototype of 200-400-V input and 360-V/4-A output is built in our laboratory to verify the operation principle of the proposed converter     

基于UCC28061的交错并联BCM Boost PFC设计

采用UCC28061设计了一款工作在交错并联临界模式下300W的电源。交错并联的Boost PFC拓扑结构,能够大大减小输入电流纹波和输出电容电流纹波。实验结果表明,AC85-265V输入时,功率在300W时PF能够达到0.99以上,电流畸变率THD在3%以下。     

Integrated magnetics for current-doubler rectifiers

This paper presents a new integrated magnetic structure for current-doubler rectifiers (CDR). Compared to previously published structures, the proposed design allows the equivalent filtering inductance to be increased with significantly less increase in total winding conduction loss. The increased inductance leads to reduced current and voltage ripple, thereby reducing the size of capacitors required for output filtering. The lower current and flux ripple also helps to reduce the conduction loss and the magnetic core loss. As the result, the overall converter efficiency can be improved, especially under light load when the losses due to ripple current and ripple flux are more significant. Analysis of the proposed structure is presented in the paper, along with an equivalent circuit model suitable for steady-state and dynamic response analyses. Detailed design procedures are also provided by using a half-bridge converter as example. Experimental results from two 100-W, 3.3-V output half-bridge converters are presented to validate the concept and the analyses.     

Improved control strategy on single-phase buck-type power factor correction converter

A buck-type power factor correction (PFC) converter is not only effectively capable of eliminating utility input current harmonics; its related characteristics also include high efficiency, absence of inrush current, capability of obtaining low dc output voltage, ability to protect against short circuit, and so forth. On the other hand, because this type of rectifier must employ inductors design for high inductance, the buck-type PFC converter tends to increase the volumetric size and weight, and this has prevented its widespread use. This paper presents a new control strategy for this type of converter which can reduce the size and weight of the inductor and also eliminate the ripple components included in the output voltage waveform. The operating principle, simulation and experimental results obtained by a prototype rectifier are described.     

Novel ZVS DC-DC converter with low current ripple for light rail transit

This paper develops and studies a three-level zero-voltage turn-on converter for providing auxiliary power system in a DC light rail vehicle. The proposed converter includes a three-level circuit and a half-bridge circuit sharing the same power switches on the high voltage side in order to reduce switch counts and distribute total power into two circuits. The Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with a low voltage rating and a turn-on resistance are adopted in the developed converter in order to decrease conduction losses on power switches. On the secondary side, two inductors and four rectifier diodes are employed to reduce output ripple current and transformer secondary winding turns. A duty cycle control based on the phase-shift pulse-width modulation is used to regulate the output voltage and achieve the wide range of zero-voltage turn-on. Experimental results with a prototype with a 760 V input and a 48V/30A output are provided to verify the feasibility and effectiveness of the developed converter.     

Zero-voltage and zero-current-switching PWM hybrid full-bridge three-level converter

This paper proposes a zero-voltage and zero-current-switching pulsewidth modulation hybrid full-bridge three-level (ZVZCS PWM H-FB TL) converter, which has a TL leg and a two-level leg. The voltage stress of the switches of the TL leg is half of the input voltage, and the switches can realize ZVS, so MOSFETs can be adopted; the voltage stress of the switches of the two-level leg is the input voltage, and the switches can realize ZCS, so IGBT can be adopted. The secondary rectified voltage is a TL waveform having lower high-frequency content compared with that of the traditional FB converters, which leads to the reduction of the output filter inductance. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results. Several ZVZCS PWM H-FB TL converters are also proposed in this paper.     

Control of Single-Phase-to-Three-Phase AC/DC/AC PWM Converters for Induction Motor Drives

This paper proposes a novel control scheme of single-phase-to-three-phase pulsewidth-modulation (PWM) converters for low-power three-phase induction motor drives, where a single-phase half-bridge PWM rectifier and a two-leg inverter are used. With this converter topology, the number of switching devices is reduced to six from ten in the case of full-bridge rectifier and three-leg inverter systems. In addition, the source voltage sensor is eliminated with a state observer, which controls the deviation between the model current and the system current to be zero. A simple scalar voltage modulation method is used for a two-leg inverter, and a new technique to eliminate the effect of the dc-link voltage ripple on the inverter output current is proposed. Although the converter topology itself is of lower cost than the conventional one, it retains the same functions such as sinusoidal input current, unity power factor, dc-link voltage control, bidirectional power flow, and variable-voltage and variable-frequency output voltage. The experimental results for the V/f control of 3-hp induction motor drives controlled by a digital signal processor TMS320C31 chip have verified the effectiveness of the proposed scheme     

Zero-voltage-switching PWM hybrid full-bridge three-level converter

This paper proposes a zero-voltage-switching (ZVS) pulse-width modulation (PWM) hybrid full-bridge three-level converter, which has a three-level leg and a two-level leg. The switches of the three-level leg sustain only the half of the input voltage, and they can realize ZVS in a wide load range. The switches of the two-level leg sustain the input voltage, and they can realize ZVS with the use of the resonant inductance. The secondary rectified voltage is a three-level waveform having lower high-frequency content compared with that of the traditional full-bridge converters, which can reduce the output filter, and as a result, the dynamic response of the converter is improved. The voltage stress of the rectifier diode is reduced also. The input current of the converter has quite little ripple, so the input filter can also be significantly reduced. The operation principle of the proposed converter is analyzed and verified by the experimental results.     

High-Efficiency Fuel Cell Power Conditioning System With Input Current Ripple Reduction

A high-efficiency fuel cell power conditioning system with input current ripple reduction is proposed. The proposed system consists of a high-efficiency high-step-up current-fed resonant push–pull converter and a full-bridge inverter. The converter conserves inherent advantages of a conventional current-fed push–pull converter such as low input-current stress and high voltage conversion ratio. Also, a voltage-doubler rectifier is employed in order to remove the reverse-recovery problem of the output rectifying diodes and provide much higher voltage conversion ratio. The current ripple reduction control without an external component is suggested. Therefore, the proposed system operates in a wide input-voltage range with a high efficiency. By using a current-ripple reduction control, the input current ripple is furthermore reduced. A 1.5-kW prototype is implemented with input-voltage range from 30 to 70 V. Experimental results show that minimum efficiency at full load is about 92.5% and that ripple current is less than 2% of the rated input current.