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This paper presents an improved circuit design of Gallium Nitride (GaN) based phase shifted full bridge (PSFB) converters along with a new adaptive burst mode control strategy, to achieve high efficiency over a wide power range, including light loads. The main challenges of PSFB converters addressed in this paper are: load-dependent zero-voltage sw...
Contexts in source publication
Context 1
... can be noticed that compared to Si devices, GaN devices have smaller C oss and faster di/dt, which lead to more frequent ringing and higher over-voltage peaks. To reduce this ringing, a diode clamping circuit is adopted as shown in Fig. 6. The ringing starts at the drain voltages of Q 5 and Q 6 and can be reflected to the primary side by the transformer. Thus, introducing D 1 and D 2 shown in Fig. 6 to clamp the voltage V T , can reduce the ringing issue. Its performance is shown in Fig. 7 (b) based on the simulation of a 375 V input, 70 V output GaN-based PSFB ...
Context 2
... devices have smaller C oss and faster di/dt, which lead to more frequent ringing and higher over-voltage peaks. To reduce this ringing, a diode clamping circuit is adopted as shown in Fig. 6. The ringing starts at the drain voltages of Q 5 and Q 6 and can be reflected to the primary side by the transformer. Thus, introducing D 1 and D 2 shown in Fig. 6 to clamp the voltage V T , can reduce the ringing issue. Its performance is shown in Fig. 7 (b) based on the simulation of a 375 V input, 70 V output GaN-based PSFB converter. Operating waveforms without clamping circuits are also included in Fig. 7 (a) as a ...
Citations
... where the phase shift of the PSFB converter is represented by D and Ts is the sampling period (Yao et al., 2022). ...
... In [113,155], an asymmetric pulse-width modulation strategy was adopted for the circulation problem so that the converter could achieve high efficiency in a wide range of output voltages. In [156], a new adaptive-burst-mode control strategy was proposed, which achieved a smaller effective switching frequency and lower switching loss. In [111], aiming to address some of the technical defects of PSFB converters in EV applications, such as the large circulating current and large reverse power, an improved control scheme was proposed by adjusting the phase-shift angle and duty cycle to increase the pre-charging stage and common charging stage. ...
With the rapid development of the electric vehicle (EV) industry, charging facilities for electric vehicles are gradually improving, thus meeting the demand for fast and safe charging. This paper comprehensively describes the current development status and future development trend of EVs and their charging infrastructure and analyzes in detail the EV fast-charging system architecture according to the AC/DC coupling configuration. The topologies and control techniques of the front AC/DC converter and rear DC/DC converter for the charging system are discussed, providing a reference for the future design of hundred-kilowatt level and above fast-charging systems for EVs. In addition, this paper summarizes the EV charging interface and the charging specifications applicable to the hundred-kilowatt power fast-charging system, as well as the impact of fast charging on power batteries, and emphasizes that high-power fast-charging technology is an inevitable trend for the future development of electric vehicles.
... 5) Low cost. To cover the above stringent requirements many concepts in design have been suggested in the literature [1], [2], [3], [7], [8], [9], [10], [11], [13], [14], [15], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32]. Notably, according to [1], [2], and [3], there are two concerns that should be particularly focused on, which decide the other remaining requirements. ...
... However, the small duty-cycle conditions place converters operating with wide circulation duration, therefore, low efficiency, large output ripple current, and large output voltage ringing [1], [2], [3], [4], [10], [22], [23], [24]. While the PSFB converter can be lost ZVS operation with a large N p :N s ratio because increasing N p :N s results in reducing primary current and consequently decreases the leakage inductor energy [22], [25], [26]. The high input voltage also puts pressure on primary switches. ...
... Because these internal diodes are opposite parallel with main switches, the current through these diodes is typically the re-generation current from the inductive source in the circuit back to the input source. It is the situation of the conventional PSFB converter and the proposed converter when inductive energy from the leakage inductor L lk of the transformer transfers to the input source in dead-time intervals [25], [26]. However, in the full parasitic model of switches, besides diodes, there is a parasitic capacitor C oss , which is also parallel with the main switches. ...
This paper proposes a new isolated high step-down DC-DC converter based on the phase-shift full-bridge converter. The proposed converter has some properties very suitable for high step-down applications including a high step-down ratio, low transformer turns ratio, low voltage stress on power switches, wide soft-switching range, and no saturation problem. These attractive features are achieved by a simple pulse-width modulation control method and a unique split-capacitor structure on the input side. By split-capacitor structure, both switching voltage and stress voltage are decreased significantly. As a result, the required ZVS energy is reduced greatly, which means that an extended ZVS range can be obtained. This structure also leads to an inherent high step-down ratio, low transformer turns ratio, and de-saturation feature because the primary transformer voltage is decreased to a quarter of the input voltage and there are capacitors in series with the primary winding in power modes. In this paper, the operation principle is presented; the ZVS range and de-saturation feature are discussed in detail. In addition, a comprehensive comparison with some new isolated high step-down converters in the literature is also completed. Finally, a simulation verification using the LTSpice simulation program and an 800 W, 400 V input, and 48 V output prototype are developed and tested to verify the salient features of the proposed converter.
This paper presents a new phase-shifted full-bridge topology using a new variable inductor. In this topology, a variable inductor is connected in parallel with a near-ideal transformer. The ZVS of the switches is achieved over the full load range using the parallel current provided by the variable inductor. And the adjustable parallel current reduces conduction losses. Under the orthogonal DC magnetic potential, the variable inductor has similar characteristics to the saturated inductor, which is beneficial to reduce the conduction loss caused by the parallel current. Since the topology has no series inductor and the leakage inductor is extremely small, the proposed converter has the advantages of extremely small duty cycle loss, larger transformer turns ratio, smaller primary current stress, smaller secondary voltage stress, and smaller output current ripple, which are beneficial to improve the efficiency and frequency of the converter. An experimental platform was established. Theoretical analysis and experimental verification were carried out.
This article proposes a two-stage power converter with novel control methods for pulsed load applications. The first stage is an isolated converter that transfers only average power to the second stage, which dramatically reduces the input filter size and components’ current rating. The second stage is a buck converter designed for a fast response during pulsed load transients. A flexible intermediate voltage is implemented to reduce the size of the midpoint energy storage capacitor that is responsible for compensating the instantaneous power difference between the two stages. A novel digital input feed-forward controller is proposed for the second stage to eliminate the poor line regulation issue caused by the flexible intermediate voltage. To verify the effectiveness of the two-stage power supply and the control methods, a full-scale 800 W (average)/4 kW (peak) converter prototype is built and tested. The results prove the feasibility of the proposed topology as well as control methods and demonstrate the advantages over traditional concepts.
