Demonstration of 13.56-MHz class-E amplifier using a high-Voltage GaN power-HEMT

A 13.56-MHz class-E amplifier with a high-voltage GaN HEMT as the main switching device is demonstrated to show the possibility of using GaN HEMTs in high-frequency switching power applications such as RF power-supply applications. The 380-V/1.9-A GaN power HEMT was designed and fabricated for high-voltage power-electronics applications. The demonstrated circuit achieved the output power of 13.4 W and the power efficiency of 91% under a drain-peak voltage as high as 330 V. This result shows that high-voltage GaN devices are suitable for high-frequency switching applications under high dc input voltages of over 100 V.     

An energy transmission system for an artificial heart using leakageinductance compensation of transcutaneous transformer

A power supply system using a transcutaneous transformer to power an artificial heart through intact skin has been designed and built. In order to realize both high-voltage gain and minimum circulating current, compensation of leakage inductances on both sides of a transcutaneous transformer is proposed. A frequency region which realizes the robustness against coupling coefficient and load variation is identified. In this region, the power converter has inherent advantages such as zero-voltage switching (ZVS) or zero-current switching (ZCS) of the switches, high-voltage gain, minimum circulating current and high efficiency     

Stability in high-output-voltage push-pull current-fed converters

The relationship between the magnetizing inductances of a transformer and of a choke coil in high-voltage power supplies is studied. The analysis defines the conditions for high switching frequency and stable operation of high-voltage power supplies without power loss increases. This approach is confirmed by the implementation of a high-voltage power supply operating at 200 kHz with an efficiency of 86%     

A 97.8% Efficient GaN HEMT Boost Converter With 300-W Output Power at 1 MHz

A 175-to-350 V hard-switched boost converter was constructed using a high-voltage GaN high-electron-mobility transistor grown on SiC substrate. The high speed and low on-resistance of the wide-band-gap device enabled extremely fast switching transients and low losses, resulting in a high conversion efficiency of 97.8% with 300-W output power at 1 MHz. The maximum efficiency was 98.0% at 214-W output power, well exceeding the state of the art of Si-based converters at similar frequencies.     

High breakdown Voltage undoped AlGaN-GaN power HEMT on sapphire substrate and its demonstration for DC-DC converter application

Undoped AlGaN-GaN power high electron mobility transistors (HEMTs) on sapphire substrate with 470-V breakdown voltage were fabricated and demonstrated as a main switching device for a high-voltage dc-dc converter. The fabricated power HEMT realized a high breakdown voltage with a field plate structure and a low on-state resistance of 3.9 m/spl Omega//spl middot/cm/sup 2/, which is 10 /spl times/ lower than that of conventional Si MOSFETs. The dc-dc converter operation of a down chopper circuit was demonstrated using the fabricated device at the input voltage of 300 V. These results show the promising possibilities of the AlGaN-GaN power HEMTs on sapphire substrate for future switching power devices.     

A new ultra-wideband fractal monopole antenna

The paper focuses on the peculiar dynamic behaviour of the recently developed 8 mm² TO-220-packaged, high-voltage, double-interdigitated (or rwo interdigi-tation levels—TIL) GTO thyristor. This novel power device was rated under both slightly and heavily inductive resistive loads, i.e. close to the real conditions encountered in practical power circuits employing GTO thyristors. Emphasis is laid on the ability of TIL GTOs to switch safely, with minimum power losses, a certain amount of anode current under high-voltage conditions and high commutation frequencies. The merits of TIL GTO thyristors are analysed in terms of their reliability and switching efficiency, which include the total power losses (conduction and switching losses), turn-on and turn-off gains and the switching speed. It is shown that thanks to their built-in self-protective features, these novel GTOs possess an enhanced current-handling capability at commutation frequencies up to 50kHz under extremely tough load conditions. The main implications of the results for power applications are outlined.     

新型数控高压电源的研制

针对电流变技术对控制高压电源要求的快速通断、智能控制以及缩小体积的要求,采用单片机技术与高频开关电源技术,设计制作了一台用于电流变元件控制的数控高压电源。本高压电源系统具有输出稳定、控制方便、体积小等优点,能满足电流变技术所要求的高电压、低电流以及高稳定性等特性。     

A soft-switching coupled inductor bidirectional DC–DC converter with high-conversion ratio

A soft-switching bidirectional DC–DC converter is presented herein as a way to improve the conversion efficiency of a photovoltaic (PV) system. Adoption of coupled inductors enables the presented converter not only to provide a high-conversion ratio but also to suppress the transient surge voltage via the release of the energy stored in leakage flux of the coupled inductors, and the cost can kept down consequently. A combined use of a switching mechanism and an auxiliary resonant branch enables the converter to successfully perform zero-voltage switching operations on the main switches and improves the efficiency accordingly. It was testified by experiments that our proposed converter works relatively efficiently in full-load working range. Additionally, the framework of the converter intended for testifying has high-conversion ratio. The results of a test, where a generating system using PV module array coupled with batteries as energy storage device was used as the low-voltage input side, and DC link was used as high-voltage side, demonstrated our proposed converter framework with high-conversion ratio on both high-voltage and low-voltage sides.     

A Three-Phase Current-Fed DC/DC Converter With Active Clamp for Low-DC Renewable Energy Sources

This paper focuses on a new three-phase high power current-fed dc/dc converter with an active clamp. A three-phase dc/dc converter with high efficiency and voltage boosting capability is designed for use in the interface between a low-voltage fuel-cell source and a high-voltage dc bus for inverters. Zero-voltage switching in all active switches is achieved through using a common active clamp branch, and zero current switching in the rectifier diodes is achieved through discontinuous current conduction in the secondary side. Further, the converter is capable of increased power transfer due to its three-phase power configuration, and it reduces the rms current per phase, thus reducing conduction losses. Moreover, a delta-delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. An efficiency of above 93% is achieved through both improvements in the switching and through reducing conduction losses. A high voltage ratio is achieved by combining inherent voltage boost characteristics of the current-fed converter and the transformer turns ratio. The proposed converter and three-phase PWM strategy is analyzed, simulated, and implemented in hardware. Experimental results are obtained on a 500-W prototype unit, with all of the design verified and analyzed.      

Characterization of hard- and soft-switching performance of high-voltage Si and 4H-SiC PiN diodes

This paper presents a study of the performance of high-voltage Si and 4H-SiC diodes in a DC-DC buck converter. Device operation in both hard- and zero-voltage switching conditions is presented with the help of measurements and two-dimensional (2-D) mixed device-circuit simulations. Experimental results show that SiC PiN diodes have a strong potential for use in high-speed high-voltage power electronics applications operating at high temperature. A combination of low excess carrier concentration and low carrier lifetime results in superior switching performance of the 4H-SiC diode over ultrafast Si diodes. Soft switching is shown to minimize the switching loss and allow operation at higher switching frequencies using Si diodes. The power loss of 4H-SiC diodes is dominated by conduction loss. Consequently, soft-switching techniques result in a marginal reduction in power loss. However, the low overall power loss implies that SiC diodes can be used at very high switching frequencies even in hard-switching configurations.     

一种380 V交流输入的多路输出开关电源

介绍了一种用于大功率IGBT厚膜驱动电路的380V系统输入、多路输出辅助开关电源。该开关电源采用新颖的双管串联模式,解决了高电压输入条件下开关管的选用难题。与传统供电电源相比,该电源电路简单、体积小、重量轻、效率高、允许输入电压范围宽,具有很高的实用价值。该电源已研制成功并已投入实际应用。     

The interruption of vacuum arcs at high DC voltages

In 1967, it was observed by the authors that an axial magnetic field applied to a vacuum-arc discharge in a coaxial diode was capable of extinguishing the discharge. A continuing effort to develop a high-voltage dc arc interrupter has resulted in a simple, lightweight device capable of interrupting 800 A at 25 kV. Operation at higher levels was limited, not by the interrupter, but by the lack of availability of adequate power supplies. This device has been operated at repetition frequencies of several pulses per second. Successful operation at a frequency of 1 kHz has been achieved at lower power levels. The turn-on and turn-off times are, respectively, as short as one and two microseconds, The pulsewidth is continuously variable from a few microseconds to infinity (dc operation). It has been demonstrated that operation above 10 kV requires very pure materials and the use of ultra-high vacuum techniques. Among the many uses for the interrupter are those in high-power modulators and high-power inverters. An enticing future application is for switching in high-voltage dc power transmission systems.     

Zero-voltage DC/DC converter with asymmetric pulse-width modulation for DC micro-grid system

This paper presents a zero-voltage switching DC/DC converter for DC micro-grid system applications. The proposed circuit includes three half-bridge circuit cells connected in primary-series and secondary-parallel in order to lessen the voltage rating of power switches and current rating of rectifier diodes. Thus, low voltage stress of power MOSFETs can be adopted for high-voltage input applications with high switching frequency operation. In order to achieve low switching losses and high circuit efficiency, asymmetric pulse-width modulation is used to turn on power switches at zero voltage. Flying capacitors are used between each circuit cell to automatically balance input split voltages. Therefore, the voltage stress of each power switch is limited at V_in/3. Finally, a prototype is constructed and experiments are provided to demonstrate the circuit performance.     

High Voltage High Frequency Class-E Converter Suitable for Miniaturization

A 120 V mains-driven class-E converter used as an electronic ballast for a 15 W fluorescent lamp is presented. The key element of the circuit is a cascoded bipolar metal-oxide semiconductor (BiMOS) switch which ensures high-voltage and high-frequency capability. In spite of the high switching frequency of 450 kHz an excellent efficiency of 91 percent could be achieved. Thus miniaturization becomes feasible.     

一种阴控速调管恒流灯丝电源的设计

阴控高功率速调管阴极工作在高压脉冲状态,灯丝电源悬浮在随阴极脉冲变化的电位上,开关稳压电源直接工作在阴极电位,极易受高压脉冲干扰无法工作。介绍了一种AC 220V输入低压端控制的恒流灯丝电源,具有抗干扰强、稳定度和可靠性高等特点。     

适用于包络跟踪的开关电源调制电路设计

包络跟踪技术已经成为提高功率放大器效率的重要研究方向,其中高效率、高功率开关电源调制器是研究重点.对实际的开关电源调制电路以及相应的参数进行了分析,提出了适用于包络跟踪技术的开关电源调制电路.利用Spice软件对设计的电路进行了电路仿真,利用Cadence软件进行了印制电路板(PCB)电路的设计.经过实际测试,该开关电源调制器的输出电压达到48 V,电流约为0.9A,整个功能模块效率接近96％.该开关电源调制电路不仅具有高效率高功率输出脉冲信号,还可以根据设计需求改变NMOS管型号,并设计出不同开关频率、不同功率输出的开关电源调制电路.     

Hi-MNOS II technology for a 64-kbit byte-erasable 5-V-only EEPROM

Improved high-performance MNOS (HiMNOS II) technology has been developed for application to a byte-erasable 5-V only 64-kbit EEPROM. A minimum feature size of 2 µm and scaling theory implementation for the MNOS device have led to the realization of a small cell size of 180 µm², a low programming voltage of 16 V, and a high packing density of 64 kbits. The high-voltage structure of the MNOS device, as well as the high-voltage circuit technology, has been developed to eliminate dc programming current in the memory array and the high-voltage switching circuits for the use of on-chip generated programming voltage. This voltage is regulated with an accuracy of ± 1 V by using a Zener diode formed in a p-type well. Moreover, in order to accomplish reliable byte erasing, high-voltage switching circuits and their control logic have been carefully designed so as to eliminate the possibility of erroneous writing or erasing due to a timing skew of the high-voltage application to the memory cells. The obtained 64K EEPROM chip shows such superior characteristics as a fast access time of 150 ns, low power dissipation of 55 mA, high-speed write and erase times of less than 1 ms, and high endurance of less than 1-percent failure after 10⁴write/erase cycles.     

Hi-MNOS II Technology for a 64-kbit Byte-Erasable 5-V-Only EEPROM

Improved high-performance MNOS (HiMNOS II) technology has been developed for application to a byte-erasable 5-V only 64-kbit EEPROM. A minimum feature size of 2 /spl mu/m and scaling theory implementation for the MNOS device have led to the realization of a small cell size of 180/spl mu/m2, a low programming voltage of 16 V, and a high packing density of 64 kbits. The high-voltage structure of the MNOS device, as well as the high-voltage circuit technology, has been developed to eliminate dc programming current in the memory array and the high-voltage switching circuits for the use of on-chip generated programming voltage. This voltage is regulated with an accuracy of /spl plusmn/1 V by using a Zener diode formed in a p-type well. Moreover, in order to accomplish reliable byte erasing, high-voltage switching circuits and their control logic have been carefully designed so as to eliminate the possibility of erroneous writing or erasing due to a timing skew of the high-voltage application to the memory cells. The obtained 64K EEPROM chip shows such superior characteristics as a fast access time of 150 ns, low power dissipation of 55 mA, high-speed write and erase times of less than 1 ms, and high endurance of less than 1-percent failure after 10/sup 4/ write/erase cycles.     

基于SG3525车载高压开关电源的启动电路的改进

分析了高压开关电源传统启动方案的不足,并在此基础上提出了基于SG3525车载高压开关电源的启动电路的改进。调试结果表明,该启动电路解决了传统启动方案中功耗大的问题．并具备了自启动功能,在设计上具有通用性。     

高压LED球泡灯的设计与分段优化

近年来在解决以开关电源为基础的传统LED驱动效率低、体积大和成本高等问题的过程中,高压线性分段驱动技术应运而生。为了研究高压线性分段驱动LED球泡灯的设计方法,以高压线性分段驱动芯片SM2087为例,通过实测LED效率得到合适的分段比例为8∶4∶3∶1;并根据该分段比例设计了一种高压LED球泡灯,LED采用COB的方式布置在陶瓷环基板上,散热采用太阳花结构,驱动电路置于灯头内,其具有较高的效率、良好的散热与耐高压能力以及较大的发光角度。