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This paper proposes a digital online efficiency optimization technique for DC/DC Dual Half-Bridge Series Resonant Converters. The proposed technique implements an advanced modulation scheme which exploits the degrees of freedom inherently available in the converter modulation space in order to simultaneously regulate the output voltage and maintain the system in its maximum efficiency point. Furthermore,...
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...
This paper derives closed-loop input and output impedances of a number of dc-dc power electronic converters when operating in a dc distribution network. The derived impedances can be used for stability analysis and control design for dc distribution networks. In this paper, first the small-signal model of a power converter operating in a dc power system is introduced and the open-loop transfer functions...
Power hardware-in-the-loop (PHIL) simulation techniques are being increasingly applied in the power system field for novel equipment testing and validation. To ensure the accuracy and stability of the overall simulation, special care must be taken in the control of the virtual power interface between the hardware under test and software simulated system. The application of wideband system identification...
This paper propose a new maximum power point tracker called fractional order extremum seeking control for grid-connected photovoltaic (PV) systems tasks to better accommodate rapid varying solar irradiance for photovoltaic (PV) arrays. The new algorithm is benchmarked against the integer order extremum seeking control and incremental conductance algorithms. Our extensive simulation results show that...
Small-signal stability in balanced three-phase systems can be analyzed using the Generalized Nyquist stability Criterion (GNC), which is based on source and load impedance in the synchronous rotating (d-q) frame. This paper models the d-q frame impedance of three-phase grid-tied inverters with current feedback control and Phase-Locked Loop (PLL). The result unveils a very interesting and important...
Droop control and some improved droop control methods are adopted to control microgrid inverters not only in island mode, but also in grid-connected mode. This paper presents a state space model of three phase paralleled inverters in grid-connected microgrid based on droop control to facilitate the control design and stability analysis. This model is established in rotation framework based on modern...
In a motor control, a voltage saturation is a serious problem as a motor speed increases. To solve the problem, various field weakening methods were studied for a long time. The field weakening methods with PI current controllers are normally used, however the voltage angle control without PI current controllers is receiving attention because of its simple implementation. In this work, the field weakening...
Current trends in power distribution systems, such as telecommunications, computers, transportation and utility grid applications, are focused on distributed architectures instead of centralized approach. Distributed architectures are more complex since a network of power electronics converters is required to distribute power with appropriate performance. Hence, new challenges regarding integration...
Conventional three-phase rectifiers are controlled to achieve good power factor and low THD in the input. In the case of pulsating power loads, the fast dynamic response implies that the load pulses are reflected in the generator. These pulsating loads affect the life time operation of the generator, especially when it is not oversized (that is the case in aircraft applications). In order to smooth...
The method of using output-current-feedforward (OCFF) control to realize zero output impedance is widely applied in Buck converter. However, it is found that the converter may have stability problems with this method. The OCFF controller's transfer functions of basic DC/DC converters are calculated when different current (inductor current, load current) feedforward control is used in this paper There...
In this paper we investigate the nonlinear dynamics of a bidirectional boost converter by employing a nonlinear analysis method based on the Monodromy matrix. This approach can be used to study the influence of system parameters for the stability of power electronics systems. Specifically, it is applied to address and control the fast-scale instability phenomena of power converters for different input...
This paper proposes an optimization method to design the parameters of controls for power converters in order to achieve a very fast dynamic response while remaining stable and robust over the desired operation region. The proposed optimization algorithm is applied to different analog controls and is used to compare the dynamic response of the Voltage mode, V2 and V2Ic control for different cases...
The traditional method of MPPT control for singlestage three/single-phase inverter typically adjusts the DC voltage reference corresponding to the power variation of PV array. This method usually has two control loops which exhibit slow response speed. This paper discusses the series connection model of solar panes and partial shading issue aroused by it. Then it proposes a direct current control...
The conventional mathematic model of PV (Photovoltaic) cells contains logarithmic terms, which is not conducive to derivation calculation in small-signal modeling. The parameters of PV system are coupling due to its double-loop control method, and it's hard to precisely choose controller parameters. To solve these two problems above, this paper is based on PV system connected to an infinite power...
The characteristic parameters of micro-grid determine its transient response and stability. Due to uncertain load changes as well as large-scale intermittent energy accesses, the micro-grid systems are always subjected to large number of random disturbances which results in micro-grid structure parameters change. To solve this problem, this paper presents a novel model for characteristic parameters...
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