Zero-voltage Zero-current Transition Research Articles

A new optimized ZV-ZCS non-isolated high-gain boost converter for renewable energy systems

Abstract This paper proposes a novel zero-voltage zero-current transition (ZV-ZCT) DC/DC high gain coupled inductor based boost converter for applications in renewable energy systems. It employs an auxiliary resonant network to soft-switch transition of semiconductor switches and soft-recovery of power diodes over wide input voltage and output power range of the converter with high efficiency. The auxiliary cell of the proposed converter has negligible impact on the converter’s overall dynamics and it doesn’t contribute any extra current stress to the semiconductor switches compared to classical hard switched boost converters. A thorough theoretical analysis of each operating mode has been presented together with the converter’s steady-state performance. The mathematical equations illustrating the dynamic behaviour of the converter have been used to design the auxiliary cell components. The circulating current loss has been minimized and simultaneously soft-switched operation of the converter is maintained through optimal selection of auxiliary cell components. Additionally, a power loss study and the proposed converter’s advantages over existing traditional converters are discussed. The converter’s soft-switching behaviour is established by hardware testing on a 400 W, 100 kHz prototype model. The theoretically predicted behaviour of the converter has been well corroborated by experimental observations.

Novel Zero-Voltage Zero-Current Transition Buck Converter With Minimal Impact of Active Auxiliary Cell on Overall Dynamics

This paper presents a novel zero-voltage zero-current transition DC/DC buck converter, which uses an active auxiliary resonant network to achieve soft switching operation of semiconductor switches and soft-recovery of power diodes over wide output power range and offers high efficiency. The auxiliary cell in the proposed converter does not cause any additional current stress on the semiconductor switches and has minimal impact on overall dynamics of the converter. Steady-state performance of the converter has been presented with detailed theoretical analysis of all operating modes. The design of auxiliary cell components and development of small signal model of the converter have been carried out from the mathematical equations depicting its dynamic behaviour. A closed loop voltage mode controller with a type III compensator has been developed for the converter to achieve the desired transient response under the influence of external disturbances. Power loss analysis and superiority of the proposed converter over other conventional configurations are also presented here. Finally, soft-switching behaviour and step-input transient response of the converter are verified by hardware experimentation on a 150W, 100 kHz prototype model. The experimental measurements have successfully validated the theoretically predicted behaviour of the converter.

An improved zero-voltage zero-current transition boost converter employing L-C-S resonant network

An improved zero-voltage zero-current transition boost converter (IZVZCTBC) is introduced. This converter is basically a fourth-order DC-DC converter wherein a L-C-S (Inductor–Capacitor–Switch) resonant circuit is embedded for soft-switching. L-C-S tank network is the modified version of conventional ZVZCT switch cell. The main feature of L-C-S tank circuit is to enhance the performance of zero-voltage zero-current transition boost converter in terms of eliminating the high current stress, decreasing the switching losses and increasing the efficiency of converter. This converter exhibits both zero-voltage turn on and zero-current turn off switching characteristics based on the gating signals applied to switches. The principle of operation and time domain expressions of IZVZCT boost converter with L-C-S cell are presented. For the closed loop operation, digital controller is designed and the performance of the controller has been validated through simulation for different line and load variations. The mathematical and theoretical analysis is verified accurately by a 12-24 V, 30 W converter through PSIM simulation software and the results ensures that overall efficiency of the converter has improved to 97% along with elimination of current stress.

Zero-voltage Zero-current Transition Network for Dual Phase Interleaved Converter

In this article, a zero-voltage zero-current transition scheme suitable for a family of dual-phase interleaved converters is proposed. The transition network consists of an auxiliary transformer, a switch, and a clamp diode. This network uses a low component count structure, and yet achieves effective soft-transitions (zero-voltage turn-ON as well as zero-current turn-OFF) for the main switches. It facilitates zero-current turn-OFF of all the diodes along with zero-current turn-ON of the auxiliary switch. Additionally, the auxiliary transformer self-adjusts the current in the auxiliary network depending upon the loading conditions and thus the reactive energy during the soft-switching is low for the entire range of loads. A detailed theoretical analysis is presented by considering a high step-up dual-phase interleaved boost converter as an example. The feasibility of the proposed soft-switching scheme is implemented on the same and its effectiveness is demonstrated through experimental results which are obtained on a 400-W converter prototype.

An Optimized Zero-Voltage Zero-Current Transition Boost Converter Realized by Coupled Inductor

In this paper, a new zero-voltage zero-current transition (ZVZCT) boost converter using coupled inductors is proposed. The feature of this topology is: the main switch can be switched on with ZVZCT, and off with zero-voltage switching, without any voltage and current stress. The auxiliary switch is turned on with zero-current switching. Other semiconductor devices can also achieve soft switching (SS). Due to the existence of the coupling effect, the current impact of the auxiliary switch is completely suppressed when it is turned off . Lower input current and output voltage in the interval of the switch- off for the auxiliary switch are just equivalent to running at a low power level, which is an additional advantage of the coupled inductor ZVZCT solution. Another advantage of the topology is that the SS condition of the main switch for each specific load can be effectively optimized just by setting the ratio of coupling inductance corresponding to the circuit design and application load. Thus, the topology design can be improved to adapt to different load types. A 100 kHz experimental prototype has been verified, different load for 1 and 0.4 kW optimization comparison has been presented, and the case without optimization is also observed.

Design and Analysis of a Novel ZVZCT Boost Converter With Coupling Effect

In this paper, a new zero voltage zero current transition (ZVZCT) boost DC–DC converter using a coupled inductor is proposed. This topology provides the main switch ZVZCT for the turn-on and zero voltage switching (ZVS) for the turn-off. Moreover, the auxiliary switch turns on at zero current switching (ZCS) and turns off at ZVS. The main diode turns on with ZVT and turns off with ZCS, and other diodes also operate under soft-switching conditions. Besides, due to the coupling effect, the proposed converter improves efficiency additionally since resonant energy in the resonance tank could be transferred to the output, and the circulating current can be limited as well. The soft-switching can be realized in almost all the load rang. In this design, there always exist energy releasing circuits to conduct magnetic flux leakage currents, such that the surge currents are eliminated and switch current stress can be accordingly reduced. All the devices resonate in a unique direction within less than half of a resonance period, so power losses with respect to the resonance can be decreased. In this paper, the converter design and operation principles of the converter are given. It also has been verified by a 1-kW experimental prototype with switching frequency of 100 kHz, and the related experimental results are presented.

소프트 스위칭 형태의 보조 회로를 이용한 인터리브드 벅 컨버터

This paper proposes the interleaved buck converter using a soft switching auxiliary circuit. In this scheme, an auxiliary circuit is added to the conventional interleaved buck converter and used to achieve soft-switching conditions for both the main switch and freewheeling diode. In addition, the switch in the auxiliary circuit operates under soft-switching conditions. Also, according to the input to output conditions, the main switch achieved zero-current-transition(ZCT) or zero-current & zero-voltage-transition(ZCZVT) at turn on. Thus, the proposed interleaved buck converter provides a higher efficiency. The basic operations, in this paper, are discussed and design guidelines are presented. The usefulness of the proposed converter is verified on a 200kHz, 180W prototype converter.

Dynamics on a ZCZVT soft-switching DC/DC boost converter

The non-floating switches, zero-current–zero-voltage-transition (ZCZVT) soft-switching DC/DC boost power converter is proposed in this article. The AC small-signal mathematical model for the ZCZVT boost converter is then derived. It shows that the ZCZVT boost converter exhibits better dynamical behavior than the conventional PWM boost converter. The accuracy of theoretical results is verified by experiments and simulations. In addition, a classical and a modified integral variable structure controllers are designed to achieve output voltage regulation. They are used to eliminate the effect of the variations of input voltage and load on the output voltage. The performances of the proposed converter with these controllers are also validated by experimental results.

Zero-current zero-voltage transition inverters with magnetically coupled auxiliary circuits: analysis and experimental results

Hitherto, zero-current transition (ZCT) and zero-current zero-voltage transition (ZCZVT) inverters have provided desirable switching conditions for main semiconductors, chiefly for minority carrier ones, by means of a current impulse that unavoidably increases the reactive energy of the auxiliary circuit, penalising their efficiency and device ratings. This often offsets the benefits gained by the above-mentioned soft-switching techniques. This study presents a novel family of ZCZVT inverters that overcome this problem by using a non-resonant auxiliary circuit, which is magnetically coupled to the filter inductor, reducing the inverter component count, and associated circuitry. The principles of operation of the ZCZVT inverter with a magnetically coupled auxiliary circuit is presented and analysed. Experimental results from a 1 kW, 40 kHz, laboratory prototype are used to verify the theoretical analysis and also to compare different technologies applied to the auxiliary switches. The ZCZVT inverter with a magnetically coupled auxiliary circuit and MOSFET-based auxiliary switches presented the highest efficiency, achieving 96% at full load, meanwhile its insulated gate bipolar transistor (IGBT)-based counterpart reached 94.2%.

Zero-current Zero-voltage Transition Pwm Converters With Magnetically Coupled Auxiliary Circuit

This paper presents a novel methodology to synthesize Zero-Current Zero-Voltage Transition (ZCZVT) topologies. The proposed methodology is based on the Auxiliary Voltage Source (AVS) concept, which permits extend the proposed new circuits to an entire class of converters. As the AVS concept is derived directly from the Resonant Transition mechanism, the new class of ZCZVT converters resembles some of the well-known Zero-Voltage Transition (ZVT) converters, holding their main advantages such as simplicity, low reactive energy and high performance. Theoretical and experimental analyses are carried out throughout the paper taking the boost converter as the case study. Nevertheless, it can be extended to other PWM topologies, even the AC-DC and DC-AC converters. Experimental and comparative results have been obtained from three laboratory prototypes rated to 1 kW, 50 kHz, confirming the feasibility of the novel synthesis concept and also the reliability of the new ZCZVT converters in what refers to efficiency as well as to di/dt and dv/dt control.