A new parallel ZVS converter with less power switches and low current stress components

A new direct current (DC)/DC converter with parallel circuits is presented for medium voltage and power applications. There are five pulse‐width modulation circuits in the proposed converter to reduce current stress at low voltage side for high output current applications. These five circuits share the same power switches in order to reduce switch counts. To reduce the converter size, conduction loss, and voltage stress of power semiconductors, the series connections of power metal‐oxide‐semiconductor field‐effect transistor (MOSFET) with high switching frequency instead of insulated gate bipolar transistor (IGBT) with low switching frequency are adopted. Thus, the voltage stress of MOSFETs is clamped at half of input voltage. The switched capacitor circuit is adopted to balance input split capacitor voltages. Asymmetric pulse‐width modulation scheme is adopted to generate the necessary switching signals of MOSFETs and regulate output voltage. Based on the resonant behavior at the transition interval of power switches, all MOSFETs are turned on under zero voltage switching from 50% load to 100% load. The circuit configuration, operation principle, converter performance, and design example are discussed in detail. Finally, experimental verifications with a 1.92 kW prototype are provided to verify the performance of the proposed converter. Copyright © 2015 John Wiley & Sons, Ltd.     

A novel prototype of auxiliary edge resonant bridge leg link snubber‐assisted soft‐switching sine‐wave PWM inverter

This paper proposes a new circuit topology of the three‐phase soft‐switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant bridge leg‐commutation‐link soft‐switching snubber circuit with pulse current regenerative feedback loop as compared with the typical auxiliary resonant pole snubber discussed previously. This three‐phase soft‐switching PWM double converter is more suitable and acceptable for a large‐capacity uninterruptible power supply, PFC converter, utility‐interactive bidirectional converter, and so forth. In this paper, the soft‐switching operation and optimum circuit design of the novel type active auxiliary edge resonant bridge leg commutation link snubber treated here are described for high‐power applications. Both the main active power switches and the auxiliary active power switches achieve soft switching under the principles of ZVS or ZCS in this three‐phase inverter switching. This three‐phase soft‐switching commutation scheme can effectively minimize the switching surge‐related electromagnetic noise and the switching power losses of the power semiconductor devices; IGBTs and modules used here. This three‐phase inverter and rectifier coupled double converter system does not need any sensing circuit and its peripheral logic control circuits to detect the voltage or the current and does not require any unwanted chemical electrolytic capacitor to make the neutral point of the DC power supply voltage source. The performances of this power conditioner are proved on the basis of the experimental and simulation results. Because the power semiconductor switches (IGBT module packages) have a trade‐off relation in the switching fall time and tail current interval characteristics as well as the conductive saturation voltage characteristics, this three‐phase soft‐switching PWM double converter can improve actual efficiency in the output power ranges with a trench gate controlled MOS power semiconductor device which is much improved regarding low saturation voltage. The effectiveness of this is verified from a practical point of view. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 64–76, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20207     

A Novel Driving and Protection Circuit for Reverse-Blocking IGBT Used in Matrix Converter

A novel drive and protection circuit for reverse-blocking insulated gate bipolar transistor (RB-IGBT) is proposed in this paper. For the drive circuit, a dynamic current source is introduced to reduce the turn-on and turn-off transients. Meanwhile, the di/dt of the collector current and the dv/dt of the collector-emitter voltage are strictly restricted, so do the respective stresses. The drive circuit consists of a conventional push-pull driver and two controllable current sources-a current generator and a current sink. These two current sources work in switching transitions. For the protection circuit, a novel collector current detecting circuit suitable for RB-IGBT is proposed. This method detects the collector current by sensing collector-emitter voltage of the device. Further study shows that this method can be used to acquire the current signs in commutation transitions of matrix converter. A series of experiments has been carried out concerning the proposed drive and protection circuit and the experimental setup; results as well as detailed analysis are presented     

A novel three‐phase converter using a three‐phase series chopper

This paper proposes a novel three‐phase converter using a three‐phase series chopper. The proposed circuit is composed of three switching devices, three‐phase diode bridge, input reactors, and LC low‐pass filter. In the conventional circuit, which combines three‐phase diode bridge and boost voltage chopper, to obtain sinusoidal input current the output voltage must be two or three times larger than the maximum input line voltage. However, in the proposed circuit, the input current can be controlled to be sinusoidal also when the output voltage is the same as the maximum input line voltage. This can be achieved because in the proposed circuit the discharging current of the reactors does not flow through the voltage source. The control method of the proposed circuit is as simple as that of the conventional circuit since all three switching devices are simultaneously turned on and off. This paper discusses the theoretical analysis and the design of the proposed circuit. In addition, simulation and experimental results are reported. The proposed circuit has obtained a 93% efficiency, and 99.7% at 1.3kW load as the input power factor. © 2000 Scripta Technica, Electr Eng Jpn, 132(4): 79–88, 2000     

软开关功率放大电路及其在高频电刀中的应用

介绍一种采用软开关技术的功率放大电路.该电路能有效地降低功率放大电路中的开关功率损耗,并在相同电源电压的情况下达到更大的输出功率.推导了该电路输出功率的近似解,给出了电路参数的设计公式,并介绍了它在高频电刀中的应用.仿真实验表明,该电路能输出较大的功率和达到较高的效率,非常适合高频电刀的应用.     

Efficient output waveform evaluation of a CMOS inverter based on short‐circuit current prediction

A novel approach for obtaining the output waveform, the propagation delay and the short‐circuit power dissipation of a CMOS inverter is introduced. The output voltage is calculated by solving the circuit differential equation only for the conducting transistor while the effect of the short‐circuit current is considered as an additional charge, which has to be discharged through the conducting transistor causing a shift to the output waveform. The short‐circuit current as well as the corresponding discharging current are accurately predicted as functions of the required time shift of the output waveform. A program has been developed that implements the proposed method and the results prove that a significant speed improvement can be gained with a minor penalty in accuracy. Copyright © 2002 John Wiley & Sons, Ltd.     

A High-Efficiency Audio Power Amplifier Using a Self-Oscillating Switching Regulator

A new high-efficiency audio power amplifier has been developed. This amplifier consists of a conventional power amplifier and a self-oscillating switching power supply which is arranged to vary the power supply output voltage according to the input signal voltage. The new amplifier achieves a higher efficiency than the conventional amplifier, by making the collector voltage of the emitter-follower-transistor follow the waveform of the output signal. Applying this idea to class A amplifiers, a one-third power dissipation can be achieved compared with the conventional class A amplifier. A power MOSFET is used as a switcher. The switching frequency is from 150 kHz to 300 kHz. The new amplifier shows sufficient favorable characteristics. Switching noise is suppressed to a low noise level, which has no influence on the AM tuner or other audio equipment. By stabilizing the single-ended push-pull (SEPP) output transistors, the amplifier can reproduce high quality tone. The present idea is also applicable to dass B power amplifiers and may be suitable for PA or car audio power amplifiers.     

采用双环控制的多电平D类功率放大器

介绍了一种新颖的基于级联型多电平拓扑结构的开关式功率放大器,采用相移PWM技术,其开关频率是单个单元开关频率的2N倍,通过电压电流双闭环控制保证输出信号的跟随品质,本文着重研究了双闭环控制的设计方法.试验结果表明,采用电流电压双闭环控制的D类功率放大器,系统带宽较宽,具有较好的瞬时响应和输出品质.     

一种新型的全桥零电压零电流开关PWM变换器

提出一种新型的FB-ZVZCS—PWM变换器拓扑，采用耦合电感构成辅助电路，结构简单、没有耗能元件或有源开关，不增加原边电流应力。新拓扑具有良好的通用性，对采用不同箝位方式如阻容吸收、次级无源箝位或有源箝位的全桥变换器均适用。变换器主开关管全部采用IGBT，开关频率大幅提高，功率密度、轻载效率及软开关负载范围显著改善，而变换器成本降低。给出了变换器拓扑结构、关键参数设计及实测波形，新拓扑已应用在3kW，350VDC变换器中。     

新型SRM功率变换器主电路研究

提出了一种新型SR电动机功率变换器主电路 ,和传统的不对称半桥电路相比较 ,新型电路所使用的主开关器件个数少 ;实现了主开关器件的零电压关断 ,改善了开关性能 ;续流时 ,绕组承受的反向电压可达正向导通电压的 2 5倍 ,从而使续流时间缩短 ,输出转矩增加 ,效率提高 ;利用LC谐振电路使续流时储存在电容中的能量转移到相邻相 ,提高了调速系统的功率因数。本文用非线性磁参数法 ,以 3相 6 / 4极SR电动机为研究对象 ,分别对传统不对称半桥电路和新型电路驱动时的稳态性能 ,进行了仿真研究。     

一种基于单片机的数控开关电源设计

基于单片机的数控开关电源是利用单片机实现对开关电源的输出电压设定、输出电压步进调整、输出电压和输出电流显示等数字控制。本文设计的数控开关电源由两部分组成。开关电源部分采用基于PWM控制的不对称半桥功率变换器,由模拟控制芯片KA3525产生PWM信号经驱动电路实现对功率变换电路的输出电压控制,实现电压的稳定输出。数控部分采用凌阳单片机的D／A输出对KA3525的误差比较器的参考端进行数字给定,实现对输出电压的设定、步进调整和显示等功能。文中给出了系统设计框图,对各部分电路进行了分析,并给出了必要的实验波形,经测试证实设计方法是可行的。将成熟的单片机技术与现有的开关电源技术进行简单结合实现数控,值得借鉴。     

一种大容量开关电源并联系统均流技术的研究

提出了一种按平均电流值自动均流的实用电路。其中开关电源模块采用电压和电流控制的双回路控制模式,使得输出电流得到有效控制,从而使开关电源的各模块达到均流的目的,提高了整个电源系统的可靠性,具有一定的实用性。     

一种可控恒流脉冲刺激器设计

为满足术中神经监测系统中运动诱发电位刺激器的设计需求,设计了一种可控恒流脉冲刺激器。采用2个基于UC3845的反激式开关电源产生所需电压,IGBT作为总开关管控制脉冲发放,三极管控制电路实现恒流。刺激器的特点是输出脉冲参数调节范围大、输出档位多、控制精度高、响应速度快而且档位多。当所有设置完成后,刺激器能在100ms内实现脉冲发放,最大输出脉冲幅度为100mA,脉冲各参数相对误差都小于5%。测试结果表明,刺激器各项指标都达到了设计要求,该刺激器也可用于其他需要输出恒流脉冲的场合。     

基于AT89S52单片机的开关电源设计

主要论述了基于AT89S52单片机的一种开关电源的设计原理及实现方法,采用开关电压调压芯片LM2596作为主控单元,主控制器通过控制程控电阻模块,实现并联供电系统输出电流的自动调节分配.同时芯片连接电流传感电路与过流保护电路,对输出电流实时检测,并反馈给主控器,实现过流保护.供电系统输出稳定的直流电压,并且供电效率达到60％以上,设计的产品可应用于通信设备和电子产品中,实用性较高.     

A power decoupling control method for an isolated single‐phase AC‐to‐DC converter based on a high‐frequency cycloconverter

This paper proposes a new power decoupling method for a high‐frequency cycloconverter which converts the single‐phase line‐frequency ac input to the high‐frequency ac output directly. The cycloconverter consists of two half‐bridge inverters, two input filter capacitors, and a series‐resonant circuit. The proposed power decoupling method stores the input power ripple at double the line frequency in the filter capacitors. Therefore, the proposed method achieves a unity power factor in ac input and a constant current amplitude in the high‐frequency output without any additional switching device or energy storage element. This paper theoretically discusses the principle and operating performance of the proposed power decoupling method, and the viability is confirmed by using an experimental isolated ac‐to‐dc converter based on the high‐frequency cycloconverter. As a result, the proposed power decoupling method effectively improved the displacement power factor in the line current to more than 0.99 and reduced the output voltage ripple to 4% without any electrolytic capacitor.     

Analytic transient solution of SCFL logic gates

In this paper we propose the analytical solution of switching transients for SCFL logic gates. The analysis of an SCFL logic gate is carried out without linearization and can be brought back to multiple analyses of a basic cell, given by a differential pair with switching input voltages and a variable tail current, to take the effect of series‐gating into account. The differential equation for this cell is a Riccati equation, if a quadratic current–voltage relationship is used for the transistors, and it can be solved by the infinite power series method, in case of polynomial input signals. An algorithm is proposed to analyse the full transient of a complex SCFL gate. This provides a closed form expression for transient signals in terms of circuit and device parameters, that can be used for symbolic analysis or fast time‐domain numerical simulation. Some case studies are presented for SCFL gates using OMMIC ED02AH technology, and a good agreement between the proposed model and SPICE simulations using complex device models is obtained. Copyright © 2005 John Wiley & Sons, Ltd.     

Hybrid DC–DC converter with high efficiency,wide ZVS range,and less output inductance

In this paper, a new soft switching direct current (DC)–DC converter with low circulating current, wide zero voltage switching range, and reduced output inductor is presented for electric vehicle or plug‐in hybrid electric vehicle battery charger application. The proposed high‐frequency link DC–DC converter includes two resonant circuits and one full‐bridge phase‐shift pulse‐width modulation circuit with shared power switches in leading and lagging legs. Series resonant converters are operated at fixed switching frequency to extend the zero voltage switching range of power switches. Passive snubber circuit using one clamp capacitor and two rectifier diodes at the secondary side is adopted to reduce the primary current of full‐bridge converter to zero during the freewheeling interval. Hence, the circulating current on the primary side is eliminated in the proposed converter. In the same time, the voltage across the output inductor is also decreased so that the output inductance can be reduced compared with the output inductance in conventional full‐bridge converter. Finally, experiments are presented for a 1.33‐kW prototype circuit converting 380 V input to an output voltage of 300–420 V/3.5 A for battery charger applications. Copyright © 2015 John Wiley & Sons, Ltd.     

基于IGBT的宽范围线性功率放大技术

模块化多电平分级逐段线性化思想可以大幅提高线性功率放大器的效率,绝缘栅双极型晶体管IGBT(insulated gate bipolar transistor)作为一种大功率器件用于其中将会大大简化大功率放大器的电路,但IGBT的类别中没有P沟道管,传统的复合P管用于线性功率放大时存在输出电压动态范围不足的问题.首先分...     

低电压大电流软开关电源的设计

本文介绍了一种大功率低压大电流开关电源的设计方案,该电源满载输出功率为60kW（5000A／12V）,采用软开关移相全桥控制方式,实现了零电压软开关;控制电路中采用了稳压稳流自动转换方案,实现了输出稳压稳流的自动切换,提高了输出性能;采用多个变压器串并联结构,使并联的输出整流二极管之间实现自动均流;设计并使用了容性功率母排,减小了系统中的振荡,减小了功率母排的发热,达到了令人满意的实验结果。     

On the two‐port network analysis of common amplifier topologies

Using two‐port network transmission parameters, we derive exact expressions for the voltage/current gains and the input/output impedances of common amplifier topologies. The derived expressions are valid both for BJT and MOS‐based amplifiers and are independent of any particular small signal transistor model. Copyright © 2009 John Wiley & Sons, Ltd.