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In this paper, partial energy processing is applied to the current sharing technique for multiphase LLC resonant converters. The proposed circuit consists of an LLC resonant converter and a flyback converter, where the flyback converter is only used for partial energy processing. The input voltage of the LLC resonant converter is fine-tuned by the flyback converter to solve the problem of a voltage gain difference between the two phases of the LLC resonant converter caused by the error of the resonant tank components, which prevents the output current from being nonequalized. Since the compensation power is much smaller than the output power, and only one phase will be during circuit operation, the impact on the overall efficiency is minimal. Due to the low dependence between the LLC resonant converter and the flyback converter, they are operated at different switching frequencies. In addition, due to the low dependence between each phase, the circuit can be expanded using odd and even phases.

Both electric vehicles and Tokamak power supply use multiple parallel converters to realize high current operation in four quadrants. A finite‐time current sharing control algorithm based on disturbance compensation is proposed to improve the converter system's dynamic and steady‐state performance so that the system can achieve the required load current and branch‐current sharing in a finite time. In the proposed algorithm, this paper adopts a finite‐time observer for unknown disturbances in the converter system and load circuit due to disturbances, such as unknown inductance and resistance in the converter system. The results show that the load current control overshoot is minimal, and the dynamic performance of each branch current is higher than the traditional control algorithm. A finite‐time current sharing control algorithm based on disturbance compensation is proposed so that the converter system can achieve the required load current and branch current sharing in a finite time.

Microgrid technology is poised to transform the electricity industry. In the context of commercial/domestic buildings and data centers, where most loads are native direct current, DC microgrids are in fact a natural choice. Voltage stability and current/power-sharing between sources within a DC microgrid have been studied extensively in recent years. DC voltage droop control is known to have its drawbacks in that current or power-sharing is relatively poor. To eliminate this drawback, some have proposed to add a communication-based consensus control in addition to the primary voltage droop control loop. The current sharing performance is improved, however, the voltage deviation inherent in droop control requires a further, slower control to achieve voltage quality control. To overcome this complication, and reduction in response time, a low latency communication-based control technique that achieves proportional current sharing without significant voltage deviations is proposed in this work. The stability of the proposed control technique is compared to state-of-the-art using eigenvalue and transient analyses. The negative impact of communication delays on proposed control is discussed in detail.

A new control method for efficiency optimization in systems composed of parallel converters is presented in this paper. The proposed methodology considers the individual efficiency surfaces for given ratings of power and voltage and determines the optimum operating point for each converter such that the global system efficiency is maximized throughout the entire operating spectrum. Furthermore, a supervisory control strategy is proposed to manage the power-sharing of the converters according to the optimal surfaces provided by the methodology, enabling a performance enhancement for the system by improving its efficiency. Different approaches can be used to implement the active current sharing (ACS) scheme, and in-depth discussions are provided to guide the designer through the tradeoffs to achieve the desired transient and steady-state behavior for the system. Experimental results show that under light load operation, an improvement of 8.5% is achieved in comparison with a conventional technique of equal power-sharing. This points out that the proposed strategy is especially applicable and can significantly improve the performance of systems powered by batteries or renewable sources.

Planar transformers have been widely used in isolated power supplies. However, with a large current density, the parallel windings usually cannot share the current evenly. This uneven current-sharing may cause additional winding losses, and damage the performance of the power converter. In this paper, a novel central-tapped planar transformer structure is proposed. Regardless of whether it is in the first half cycle or the second half cycle, the proposed twelve-layer transformer can be simplified as four three-layer transformers connected in parallel. Moreover, there is a “shielding layer” between adjacent three-layer transformers. In addition, the proposed transformer structure is optimized with a symmetrical layer arrangement, and the skin effect and proximity effect can be further reduced. Simulation and experimental tests indicate that the optimized planar transformer can stably provide 476.1 W of output power at a frequency of 1.25 MHz. The peak efficiency of the optimized transformer is up to 99.2%, and there is no obvious hot spot on the PCB board. It is noteworthy that the temperature difference in the secondary windings is less than 5 °C, which means the current-sharing in the secondary windings works well.

Multi-chip parallel power modules are highly favored in applications requiring high capacity and high switching frequency. However, the dynamic current imbalance between parallel chips caused by asymmetric layouts limits the available capacity. This paper presents a method to optimize dynamic current distribution by adjusting the lengths and connection points of bond wires. For the first time, a response surface model and nonlinear constraint optimization algorithm are introduced, along with parameter analysis based on finite element methods, to establish the response surface models for the parasitic inductance of bond wires and DBC (direct bonded copper). By leveraging the optimization goals for parasitic inductance and the analytical expressions of all response surfaces, the dynamic current sharing issue was transformed into a nonlinear constrained optimization problem. The solution to this optimization problem identified the optimal connection points for the bond wires, enhancing dynamic current sharing performance. Simulations and experiments were conducted, revealing that the optimized automotive-grade module exhibited a significant reduction in current differences between parallel branches, from 41.7% to 5.03% compared with the original design. This indicated that the proposed optimization scheme for adjusting bond wire connection points could significantly mitigate current disparities, thereby markedly improving current distribution uniformity.

The interleaved flyback converters are widely used for the application of the renewable energy sources, electric vehicles, LED drivers et al. However, there are some challenges for this topology, such as leakage inductor energy of transformer, output current ripple, and high voltage stress of main switch. In order to solve the above problem existed in the converter, an improved interleaved flyback converter with adding series capacitor is proposed in this paper. Through utilizing of active clamp technique for the converter, leakage inductor energy is observed and released, zero voltage switching of main switch are achieved. Furthermore, intrinsic current sharing of two phase flyback converter could be automatic obtained without any voltage/current sensors by through charge balance for series capacitor existed in this converter topology. Thus, output current ripple is reduced and high efficiency of interleaved flyback converter is acquired. Comprehensive operational principle analysis and performance analysis are provided. Finally, a 60 W prototype is built to verify the analysis.

The low voltage, high current rectifier module is the core of the integrated DC output system based on synchronous generators. In addition, modular control improves the flexibility of the system control and fault-tolerant operation ability. Due to the dispersion of the on-state voltage drop of switching devices, it is possible to cause a circulating current fault between the parallel modules, which leads to the reduction of the current sharing characteristics and stability of the system. Therefore, it is significant to address the shortcomings of traditional current sharing methods such as poor anti-disturbance performance. This paper proposes a current sharing scheme that improves the control accuracy by filtering the sampled current on the basis of autonomous sharing of maximum current. Furthermore, a model of the integrated generator rectifier system was established by Simulink to realize the simulation of the modular SVPWM (Space-Vector Pulse-Width Modulation) rectifier control based on MA (Moving Average) filtering algorithm. At last, an experimental platform was built in this paper in order to verify the feasibility of the theory. In this experimental platform, the controller completes digital current sharing control and finally realizes the synchronous generator module paralleling system 5 V/1000A DC output. The simulation and experiment demonstrate that the integrated output current sharing control method in this paper has higher control precision and better anti-interference performance.

A new magnetic integrated parallel current sharing control method for parallel silicon carbide (SiC) power devices is presented in this article. The problem of the application of parallel connected SiC power devices is analyzed. The coupled inductance method is adopted to solve the problem. Based on the active-back converter, we establish the theoretical model of the coupled inductance, and figure out its working mechanism. The integrated magnetic device is designed based on the working mechanism, and the effectiveness is determined through simulation. A 12 V/10 A output magnetic integrated active-flyback converter prototype is fabricated and tested to verify the strategy. Measurement results show that, with the proposed magnetic integrated method, the mismatch voltage is suppressed to 0.1 V under all load conditions, and the efficiency increases by at most 6.52% under full load conditions.

In DC microgrids, if the oscillatory current is not shared among DGs, it may cause unallowable voltage distortion and overcurrent. In this paper, a distributed cooperative control scheme is introduced for DC microgrids in order to effectively share both the DC and the oscillatory components of current among DC sources. The hierarchical control method comprises four primary controllers namely voltage controller, conventional droop, oscillatory current droop and virtual conductance units, and three secondary controller units based on cooperative control principles. The primary controllers on each DG unit only use DGs' local information, while secondary controllers also require information of other DG units. In the secondary control part, firstly, via using the cooperative control, the DC current-sharing becomes accurate. Then, a novel droopbased oscillatory current-sharing controller unit is proposed in which by using the consensus method the error of oscillatory current-sharing is significantly reduced. A voltage observer, based on cooperative control is employed to compensate the inevitable voltage drop in DC microgrid, caused by droop controller. The voltage oscillation caused by oscillatory current-sharing unit is decreased through implementation of a virtual conductance signal applied to the inner current controller. The presented method is validated by a simulation with several cases.