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.     

Novel zero-voltage and zero-current-switching (ZVZCS) full-bridge PWM converter using coupled output inductor

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulse-width-modulated (PWM) converter is proposed to improve the previously proposed ZVZCS full-bridge PWM converters. By employing a simple auxiliary circuit with neither lossy components nor active switches, soft-switching of the primary switches is achieved. The proposed converter has many advantages such as simple auxiliary circuit, high efficiency, low voltage stress of the rectifier diode and self-adjustment of the circulating current, which make the proposed converter attractive for the high voltage and high power applications. The principles of operation and design considerations are presented and verified on the 4 kW experimental converter operating at 80 kHz.     

Zero-voltage and zero-current-switching full-bridge PWM converterusing secondary active clamp

A new zero-voltage and zero-current-switching (ZVZCS) full-bridge (FB) pulse width modulation (PWM) power converter is proposed to improve the performance of the previously presented ZVZCS FB PWM power converters. By adding a secondary active clamp and controlling the clamp switch moderately, ZVS (for leading-leg switches) and ZCS (for lagging-leg switches) are achieved without adding any lossy components or the saturable reactor. Many advantages, including simple circuit topology, high efficiency and low cost, make the new power converter attractive for high-voltage and high-power (>10 kW) applications. The principle of operation is explained and analyzed. The features and design considerations of the new power converter are also illustrated and verified on a 1.8 kW 100 kHz IGBT-based experimental circuit     

A zero-current-switching PWM flyback converter with a simpleauxiliary switch

A simple and effective approach of turning an isolated hard-switched converter design into a soft-switched one is presented. By adding an auxiliary winding, switch and small capacitor to the conventional pulsewidth modulation (PWM) isolated flyback converter, all switches and diodes are softly turned on and off. No extra active or passive voltage clamp circuit is needed to suppress voltage stress on the switching devices that were usually found in classical converters. A zero-current-switching (ZCS) PWM flyback converter topology with multiple outputs is analyzed and examined. The proposal inherently utilizes the leakage inductance of the “flyback” transformer to achieve ZCS of all switching devices. A complete steady-state DC analysis and the operating principle are described. The performance of an 80 W experimental converter prototype with dual-voltage outputs is included     

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.     

An improved full-bridge zero-voltage-switched PWM converter using asaturable inductor

The saturable inductor is employed in the full-bridge (FB) zero voltage switched (ZVS) pulse width modulated (PWM) power converter to improve its performance. The current and voltage stresses of the switches as well as parasitic oscillations are significantly reduced compared to those of the conventional FB-ZVS-PWM power converter. The qualitative analysis is presented and is verified on a 500 kHz, 5 V/40 A converter     

New family of zero-current-switching PWM converters using a new zero-current-switching PWM auxiliary circuit

A new family of zero-current-switching (ZCS) pulsewidth-modulation (PWM) converters using a new ZCS-PWM auxiliary circuit is presented in this paper. The main switch and auxiliary switch operate at ZCS turn-on and turn-off, and the all-passive semiconductor devices in the ZCS-PWM converters operate at zero-voltage-switching (ZVS) turn-on and turn-off. Besides operating at constant frequency and reducing commutation losses, these new converters have no additional current stress and conduction loss in the main switch in comparison to the hard-switching converter counterpart. The PWM switch model and state-space averaging approach is used to estimate and examine the steady-state and dynamic character of the system. The new family of ZCS-PWM converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The principle of operation, theoretical analysis, and experimental results of the new ZCS-PWM boost converter, rated 1.6 kW and operating at 30 kHz, are provided in this paper to verify the performance of this new family of converters.     

Performance characteristics of the full-bridge zero voltageswitching PWM resonant converter

The authors present the exact analysis of the full-bridge zero voltage switching (ZVS) pulse width modulated (PWM) converter by using the state-plane technique. Based on the analysis, they derive the necessary conditions for ZVS operation and the performance characteristics of the converter in terms of characteristic curves from which the converter design procedure can be formulated. The performances of the converter operating outside the limits of ZVS operation, including the switching loss and the attainable efficiency under different load conditions, are also given. The analytical work is confirmed by experimental results     

Novel zero-current-switching PWM converters

This paper presents a new family of pulsewidth-modulated (PWM) converters, featuring soft commutation of the semiconductors at zero current (ZC) in the transistors and zero voltage (ZV) in the rectifiers. Besides operating at constant frequency and with reduced commutation losses, these new converters have output characteristics similar to the hard-switching-PWM counterpart, which means that there is no circulating reactive energy that would cause large conduction losses. The new family of zero-current-switching (ZCS)-PWM converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The advantages of the new ZCS-PWM boost converter employing IGBTs, rated at 1.6 kW and operating at 20 kHz, are presented. This new ZCS operation can reduce the average total power dissipation in the semiconductors practically by half, when compared with the hard-switching method. This new ZCS-PWM boost converter is suitable for high-power applications using IGBTs in power-factor correction. The principle of operation, theoretical analysis, and experimental results of the new ZCS-PWM boost converter are provided in this paper to verify the performance of this new family of converters     

A new ZVS-PWM full-bridge converter

A full-bridge 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 rectifier. The operation and performance of the proposed converter is verified on a 670 W prototype.     

用PWM芯片实现全桥移相ZVS隔离DC／DC变换器的研究

简述了市场上现有移相控制器的简单情况,分析了全桥移相的工作原理,进而介绍了采用常规PWM控制芯片及全桥驱动器HIP4081A实现50w／500kHz全桥移相ZVS隔离DC／DC变换器,通过有效的利用变压器漏感、MOSFET的输出电感以及MOSFET的体二极管实现ZVS,大幅度降低了开关损耗、热损耗、EMI和RFI。通过深入细致的实验观察,验证了理论设计的正确性、合理性,并给出了相关的实验波形和实验结果分析。     

A novel zero-voltage and zero-current-switching PWM full-bridgeconverter using two diodes in series with the lagging leg

This paper proposes a novel phase-shifted zero-voltage and zero-current-switching (ZVZCS) pulsewidth modulation full-bridge converter, which realizes ZVS for the leading leg and ZCS for the lagging leg. A blocking capacitor is added in series with the primary winding of the transformer to make the primary current decay to zero during zero state to ensure ZCS for the lagging leg. In order to prevent the primary current from reversing during zero state, two diodes in series with the lagging leg are added. The principle of operation, steady-state analysis, and design procedures are presented. The experimental results are also included to verify the theoretical analysis     

一种实用的大功率全桥ZVZCS变换器的设计

针对当前大功率的全桥ZVZCS变换器存在功耗过高,实用率不高的问题,提出一种实用的电路拓扑结构,并对该电路拓扑进行了简单的分析。该变换器超前管采用MOSFET,实现了零电压开通和关断,滞后管采用IGBT,实现了零电流开通和关断。对变换器主电路各参数进行选定后,通过采集的相关波形,验证了设计的变换器的正确性,将该变换器应用在电力操作电源上运行,性能优良,满足了市场要求。     

Small-signal and transient analysis of a full-bridge, zero-current-switched PWM converter using an average model

This paper presents a detailed small-signal and transient analysis of a full bridge zero-current-switched (FB-ZCS) PWM converter designed for high voltage, high power applications using an average model. The development shows the model follows directly from the converter's steady-state analysis and is produced by inspection of the converter's instantaneous waveforms. The method used in model development can be extended to other topologies that are not easily modeled by conventional methods. The derived model is implemented in a PSPICE subcircuit and used to produce the small-signal and transient characteristics of the converter. Results obtained in the analysis of the high voltage and high power design example are validated by comparison to the actual, switched-circuit simulations.     

An improved zero-voltage and zero-current-switching full-bridge PWMconverter using a simple resonant circuit

An improved zero-voltage and zero-current-witching full-bridge pulsewidth modulation (ZVZCS-FB-PWM) DC-to-DC converter is presented and analyzed. An auxiliary resonant circuit, which consists of a switch and a capacitor, are added to provide zero-current switching (ZCS) conditions to the primary lagging-leg switches. Due to the auxiliary circuit, when the primary current is being extinguished, the voltage applied on the leakage inductance of the transformer is larger than DC-link voltage. This large voltage increases the maximal output current that can be handled in ZCS. Furthermore, the auxiliary switch softly turns on and turns off     

A centroid-based PWM switching technique for full-bridge inverterapplications

A novel centroid-based pulse-width-modulation (PWM) switching strategy is proposed which is suitable for full-bridge inverter applications. This method is evaluated, and its performance is compared with existing PWM switching strategies. The performance evaluation and comparison are based on the total harmonic distortion (THD) and number of pulses per cycle of the inverter output waveform. The objective of the new switching strategy is to minimize both the THD and low-order harmonics. Simulation results show that this technique yields a significant improvement in performance. In addition, a hybrid switching sequence is developed for the proposed scheme, which can lead to further reduction in switching losses     

Zero-voltage and zero-current-switching full bridge PWM converterfor high-power applications

A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge (FB) pulse-width modulated (PWM) converter is proposed. The new converter overcomes the limitations of the zero-voltage-switching (ZVS)-FB-PWM converter, such as high circulating energy, loss of duty cycle, and limited ZVS load range for the lagging-leg switches. By using the DC blocking capacitor and adding a saturable inductor, the primary current during the freewheeling period is reduced to zero, allowing the lagging-leg switches to be operated with zero-current-switching (ZCS). Meanwhile, the leading-leg switches are still operated with ZVS. The new converter is attractive for high-voltage (400-800 V), high-power (2-10 kW) applications where IGBTs are predominantly used as the power switches. The principle of operation, features, and design considerations of the new converter are described and verified on a 2-kW, 100-kHz, IGBT-based experimental circuit     

A novel pulsewidth control scheme for fixed-frequencyzero-voltage-switching DC-to-DC PWM bridge converter

A new gating pulse scheme is proposed for the control of DC-to-DC pulsewidth-modulated (PWM) bridge converter that provides zero-voltage switching (ZVS) for all the switches for a wide variation in load and input voltage. This new complementary fixed-edge gating control scheme is compared to the traditional phase shift control scheme. Modes of operation are presented and analyzed. Based on the analysis, design procedure and design curves are obtained. An optimum design is given and a design example is presented. Results obtained from PSPICE simulation for the converter designed are given to verify the performance of the proposed converter for varying load as well as line voltage. Detailed results obtained from a 500 W experimental converter are given to verify the advantages of the proposed gating scheme     

A novel single-stage full-bridge buck-boost inverter

A novel single-stage full-bridge series-resonant buck-boost inverter (FB-SRBBI) is proposed in this paper. The proposed inverter only includes a full-bridge topology and a LC resonant tank without auxiliary switches. The output voltage of the proposed inverter can be larger or lower than the dc input voltage, depending on the instantaneous duty-cycle. This property is not found in the classical voltage source inverter, which produces an ac output instantaneous voltage always lower than the dc input voltage. The proposed inverter circuit topology provides the main switch for turn-on at ZCS by a resonant tank. The nonlinear control strategy is designed against the input dc perturbation and achieves well dynamic regulation. An average approach is employed to analyze the system. A design example of 500 W dc/ac inverter is examined to assess the inverter performance and it provides high power efficiency above 90% under the rated power.     

ZVS移相全桥变换器的优化设计与仿真

针对传统的零电压(ZVS)、零电压零电流(ZVZCS)移相全桥变换器的各种缺陷以及实际参数选取困难的问题,采用一种改进型零电压移相全桥软开关变换器,即在原边钳位两个超快恢复二极管与一隔直电容来降低副边电路的寄生震荡以防止变压器进入磁饱和,为进一步提高变换器的效率,副边采用全波整流。对所设计的电路进行细致的原理分析,给出若干关键值的优化计算过程,并以UC3875作为控制芯片,通过saber仿真验证理论分析的合理性,结果表明电路在实现软开关的同时也抑制了副边整流器件的电压应力,证明了所提优化方案的可靠性。