An active‐clamping zero‐voltage‐switching flyback converter with integrated transformer

In this paper, a new multiport zero voltage switching dc-dc converter is proposed.Multiport dc-dc converters are widely applicable in hybrid energy generating systems to provide substantial power to sensitive loads. The proposed topology can operate in 3 operational modes of boost, buck, and buck-boost. Moreover, it has zero voltage switching operation for all switches and has the ability to eliminate the input current ripple; also, at low voltage side, the input sources can be extended. In addition, it has the ability of interfacing 3 different voltages only by using 3 switches. In this paper, the proposed topology is analyzed theoretically for all operating modes; besides, the voltage and current equations of all components are calculated. Furthermore, the required soft switching and zero input currents ripple conditions are analyzed. Finally, to demonstrate the accurate performance of the proposed converter, the Power System Computer Aided Design(PSCAD)/ Electro Magnetic Transient Design and Control(EMTDC) simulation and experimental results are extracted and presented. KEYWORDS input current ripple cancellation, nonisolated multiport dc-dc converter, soft switching, zero voltage switching

Section: Introductionmentioning

confidence: 99%

“…The nonisolated converters have lower losses in comparison to isolated converters. [9][10][11][12] Some multiport converters are presented in previous studies. [13][14][15] However, not only they suffer from hard switching constrains but also the related switching losses of these converters are rather high in value.…”

Section: Introductionmentioning

confidence: 99%

A new topology for nonisolated multiport zero voltage switching dc‐dc converter

Babaei

Saadatizadeh

Heris

2018

“…In recent years, the primary side‐regulated (PSR) flyback converter increasingly draws people's attention because of its elimination of opto‐coupler and feedback loop in conventional offline flyback converters . The elimination of the opto‐coupler and feedback loop would provide significant advantages such as cost reduction, higher power density and lower standby power loss.…”

Section: Introductionmentioning

confidence: 99%

Analysis and improvement of cross‐regulation effect in the primary side‐regulated multi‐output flyback converter

Guo

Luan

Liu

et al. 2017

In the multi-output primary side-regulated (PSR) flyback converters, cross-regulation effect denotes the phenomenon that change of load current in either one of the outputs would lead to the output voltage variations in other output terminals. Because the PSR flyback converters are frequently used to provide power supplies in a power system, the steady operation of the power system may be affected. Based on an improved Cantilever model, this paper proposes a thorough analysis on the cross-regulation effect in the PSR flyback converter. It has been found that the coupling between the output windings and the topology of the output terminal would have significant influence on the cross-regulation effect. Moreover, a mathematical expression has been derived to calculate the relationship, in the time domain, between the voltages of the output windings in the PSR flyback converter. In the mathematical expression, the leakage inductances in the improved cantilever model are lumped into a matrix R 0 . Hence, the winding method and the geometry of the transformer can be optimized to improve the precision of the multi-output voltages in the PSR flyback converter. A 10-W PSR flyback prototype with three output terminals is built. Experimental results are given to validate the theoretical analysis.where R L2 , R L3 and R L4 are the equivalent load resistance of the three output terminals V 2 , V 3 and V 4 . 1306 X. GUO ET AL.

“…They are popular in low power applications (<250 W) such as the single-stage flyback and forward converters [1][2][3]. The cost, size and complexity associated with operating the two stages converters are reduced in the single-stage converters.…”

Section: Introductionmentioning

confidence: 99%

“…The cost, size and complexity associated with operating the two stages converters are reduced in the single-stage converters. They are popular in low power applications (<250 W) such as the single-stage flyback and forward converters [1][2][3]. However, researches on the single-stage full-bridge (SSFB) converters, which are used in higher power applications (>500 W), are more challenging because of the larger variation in output load [4].…”

Section: Introductionmentioning

confidence: 99%

Magnetic flux density bias analysis and suppression strategy for voltage‐fed single‐stage full‐bridge converter

Zhang

Qian

et al. 2016

Power transformer in the voltage-fed single-stage full-bridge (SSFB) converter is easy to be saturated because of the special operating mode of this topology. First and foremost, detailed analysis about the generation mechanism of the transformer saturation in the voltage-fed SSFB converter is presented for the first time in this paper. Second, the mathematical expression of the maximum value of magnetic flux density bias (MFDB) during every line cycle is deduced. Furthermore, a novel suppressing strategy, consisted of the digital compensating algorithm and design considerations, is proposed based on the theoretical analysis and mathematical expression. The MFDB can be eliminated and additional circuits are not needed with the proposed strategy. Finally, a 1 kW prototype with the voltage-fed SSFB topology is built to verify the effect of the proposed approach. The voltage-second imbalance is reduced to less than 1% using the proposed suppression strategy compared with 14% when the strategy is not used. Consequently, the system reliability and the efficiency are improved. research is seldom studied comprehensively. In [10], the flux density bias problem is mentioned, and a protection circuit is used to limit the maximum magnetizing current. Detailed theoretical analysis is not involved, and the efficiency is still affected.In this paper, the generation principle of the MFDB is analyzed in detail. Then the mathematical expression of the maximum MFDB is deduced. Based on these theoretical analyses, a novel strategy is developed to avoid the transformer saturation in the voltage-fed SSFB converter. The paper is organized as follows. In Section 2, the principle of flux density bias generation is analyzed. Besides, the maximum MFDB is calculated in this section. Section 3 gives several conventional solutions for suppressing the MFDB. The proposed suppressing strategy including design consideration is presented in Section 4. In Section 5, a 1-kW prototype with voltage SSFB topology is built and tested. With the proposed strategy, the system reliability is improved, and the efficiency is increased. The conclusions are given in Section 6. GENERATION MECHANISM OF THE MFDBThe circuit diagram of the voltage-fed SSFB converter is shown in Figure 1. The two bridge legs of the full-bridge converter are composed of four transistors, Q 1 , Q 2 , Q 3 and Q 4 , in which, Q 2 and Q 4 are also used to perform the same current-shaping function as the switch in a boost converter. Components D S1 , D S2 , L 1 and L 2 make up a semi-bridgeless converter. The power transformer T r , resonant inductance L r (including the leakage inductance), output rectifier diodes D R1 and D R2 , output filter inductance L O and capacitance C O make up a standard full-bridge converter [11][12][13]]. An energy store capacitor C F is placed across the primary-side dc bus. MFDB generation mechanismThe MFDB occurs when the voltage-second balance of the magnetizing inductance is not achieved. Actually, this phenomenon may occur in most full-bridge converter b...