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This paper presents the analysis of the mechanism of failure modes in bi-directional phase-shift full-bridge converters, composed of MOSFET, based on the circuit operation and parameters considering parasitic components of MOSFET. In addition, the relation between circuit operation and parameters are suggested through the experimental comparison. Using the relation, the suitable ranges of parameters...
This paper presents an advanced switching sequence based on boundary control for the Dual Active Bridge (DAB) DC-DC converter applied in a Solid-State Transformer (SST). The implementation of the switching sequence follows the recent advancements in curved switching surfaces for DAB converters — the Natural Switching Surface (NSS) — and contributes to higher efficiency and transient regulation. The...
During grid faults, grid codes required wind turbine (WT) to provide dynamic reactive support within tens of ms as well as maintain grid connection continuously, namely low voltage ride through (LVRT). But owing to the limited DC bus voltage, the rotor side convertor in doubly fed induction generator (DFIG) cannot actually output sufficient voltage to provide reactive support until the rotor-side...
The characteristic parameters of the micro-grids determine its transient response and the stability. The generation, the grid structure and the electric loads of all the whole micro-grids are always changing randomly due to the random load changes and the integration of large-scale batch energy, indicating that the characteristic parameters of the micro-grids also changes. A novel real-time and on-line...
A new, small and efficient voltage regulator realized using a resonant switched capacitor converter (RSCC) technology is introduced. Voltage regulation is implemented by means of simple digital pulse density modulation (PDM). It displays an ideal transient response with a zero-order response to all disturbance types. The newly developed RSCC acts as a gyrator with a wide range of voltage conversion...
The output voltage transient of a buck regulator during a load current step is often a key performance specification. However, many practical design approaches are based on frequency domain specifications like bandwidth and phase margin, without explicitly considering the constraints of the output filter. This paper derives an analytical expression for the peak transient output voltage due to a load...
This paper investigates how to integrate state-trajectory control functions of LLC resonant converter within a commercial low-cost microcontroller, including Simplified Optimal Trajectory Control (SOTC) for load transient, burst mode and soft start up. Simplified calculation process is proposed for SOTC to minimize digital delay. Guideline to select a proper microcontroller is presented to limit calculation...
This paper presents an online multivariable auto-tuning digital controller for DC-DC switching power converters. In the proposed scheme, all the variables/parameters (i.e. gain, zero(s) and pole(s)) of a digital PID compensator are auto-tuned simultaneously during system operation in order to achieve an optimized compensator that results in improved dynamic performance for a given power converter...
A new equivalent circuit model is presented to predict the small-signal characteristic of current-mode control with DCR current sensing accurately, and a simple auto-tuning method is proposed to solve the issue of time constant mismatch in DCR current sensing. The model shows that the mismatch between the current sensing RC network and the output inductor makes the output impedance deviate away from...
The control of boost converters using traditional linear techniques features fixed switching frequency and a simple implementation. Due to its characteristic non-minimum phase behaviour, the dynamic response can be improved only to a limited extent. On the other hand, excellent dynamic performance can be achieved with boundary controllers in which the demands placed on processors and sensors are greatly...
There is a large body of literature on modeling, design, and analysis of static-synchronous-series-compensator (SSSC) for voltage restoration and regulation. Most of them focus on investigating the impacts of source voltage disturbance only and give less emphasis on characterizing the whole system under load disturbances. This paper will derive a mathematical model to describe the static and dynamic...
This paper presents a method for current controller design in a single phase grid-connected inverter (GCI). The proposed controller addresses the following items: transient performance; steady state tracking; output current distortions and dc; active damping; and start-up transient. The proposed controller is based on various extensions of the linear quadratic regulator (LQR) method and it inherits...
This paper proposes a new phase shedding scheme for interleaved Boost PFC converter to improve the light load efficiency. In the proposed scheme, the power level in the slave channels is reduced linearly as the output loading drops for optimization of light load efficiency. The new scheme also prevents the PFC slaves from switching between the ON and OFF states immediately after phase shedding, thereby...
This paper describes a constant on-time controlled DC-DC converter that realizes both high efficiency under light loads and fast load transient response. To realize low-power operation, a combination of a simple common-source amplifier and a low-power differential amplifier is used instead of a differential comparator. Using a common-source amplifier cuts power consumption in half compared with using...
This paper introduces a flyback-based low-volume modular converter and complementary mixed-signal controller that provide input voltage and output current sharing as well as near optimal transient response. This serial-input paralleloutput switch-mode power supply (SMPS) is well suited for high-step down ratio applications where, compared to a conventionally used multi-phase buck, it requires a smaller...
Datacenter power consumption makes up two percent of United States electricity consumption or 80TWhr. Roughly half of this energy is spent on cooling or lost in power conversion. Further as datacenters try to maximize compaction, the need for small and highly efficient power supplies is highlighted. Telecom power supplies often rely on large and lossy transformers to achieve large conversion ratios...
Rapid advancement of gallium nitride (GaN) based device technologies enables the possibility to design inverters that have superior performance capabilities compared to Si-based inverters. It is prevalently acknowledged that GaN-based switching devices outperform the Si-based counterparts in many aspects such as lower power consumption, and faster switching frequencies. GaN devices will benefit many...
This paper investigates the effects of ringing on the switching losses of wide band-gap (WBG) devices in a phase-leg configuration. An analytical switching loss model considering the parasitic inductance, stray resistance, devices' junction capacitances, and reverse recovery characteristics of the freewheeling diode is derived to identify the switching energy dissipation induced by damping ringing...
The purpose of this paper is to analyze the impact of interconnection inductances to overvoltage during turn-off transient of silicon carbide (SiC) devices. To understand the switching behavior of the SiC devices, the ringing and overshoots of the voltage caused by the device capacitance and interconnection inductances are considered. Parametric studies are conducted to compare the influences of printed...
With the stator directly connected to the grid, doubly-fed induction generator is very sensitive to gird disturbance. However, wind turbines are required to stay connected to the grid for a given time duration during grid fault, according to the low voltage ride-through requirement. The key point of the low voltage ride-through solution is to depress high rotor current during grid fault. This paper...
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