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High Voltage DC systems are gaining widespread attention due to the advances in power electronic devices and converters. MMCs are very popular nowadays in this type of application. This paper first revisits the dynamic equations of the circulating current of a MMC to incorporate a disturbance term. Based on the modified equations, a disturbance rejection controller is proposed to eliminate the double...
Synchronous generators are widely utilized in microgrids with high penetration of distributed renewable energy resources for small scale power generation. An accurate model of a synchronous generator is key to effective planning and operation of a grid-tied microgrid as well as stabilizing the frequency and regulating the voltage in an islanded microgrid. In this paper, a new strategy, based on the...
A real-time simulation for the Cascaded STATCOM fully implemented on field-programmable-gate-arrays (FPGA) is proposed in this paper. The switching-function model for the STATCOM is employed, where the IGBTs and diodes are taken as ideal switches, to reduce the amount of calculation. With the help of external circuit calculation, the operation in dead-time period is taken into consideration, which...
In recent years, there has been rapid growth of Photovoltaic (PV) system integration into diesel-based remote microgrids to reduce the diesel fuel consumption. However, due to low correlation of PV power availability with the load as well as uncertainty and variability of the PV power, the benefits of the integration have not been achieved properly. A large energy reserve is required to compensate...
This paper deals with a time-domain homogenization technique for litz-wire bundles embedded in a finite element (FE) model. An elementary FE model is used to determine dimensionless frequency- and time-domain coefficients regarding the skin and proximity effects in litz-wire bundles. Thanks to these coefficients, litz-wire bundles become homogeneous conductors which are easy to integrate into a FE...
An analysis of Hybrid Excitation Synchronous Generator (HESG) topologies for a direct drive wind turbine is investigated. Through an optimization process, the topologies of HESG are compared regarding the cost and the total losses. The optimizations are performed at the nominal on-load operating point of the generator. The trade-offs between each topology are analyzed according to a set of Pareto...
In Variable Frequency Drive (VFD) systems, long motor leads can have many detrimental effects, including cable charging current, overvoltage at the motor terminals, and voltage stress on power modules. Different types of AC system grounding can also interact with long motor leads to yield undesirable effects on drive operation. Analyzing models of various components of a drive system is useful to...
An FPGA implementation of Model Predictive Direct Current Control (MPDCC) is reported in this paper. A central scheduler enumerates switching sequences and assigns these to several explorer units, which predict the system response and compute their associated cost. The proposed FPGA design is scalable, modular and requires little hardware resources. A five-level active neutral point clamped inverter...
The modeling of Lithium-ion batteries usually utilizes discrete-time system identification methods to estimate parameters of discrete models. This paper adopts direct continuous-time system identification methods to estimate the parameters of equivalent circuit models for Lithium-ion batteries. Compared with discrete-time system identification methods, the continuous-time system identification methods...
Traditionally, the current control of grid-tied converters with LCL filter is based on proportional-resonant or proportional-integral controllers, which often need an additional active damping method to achieve stability. These solutions do not permit to place the closed-loop poles in convenient locations when dealing with such high-order plants. This constraint results in degraded reference-tracking...
Simulation of modular multilevel converter (MMC) based high-voltage direct current (HVDC) systems assumes significance due to their growing popularity. It could assist with the design of hardware, control systems of MMC and HVDC networks, and power system topology. However, simulation of MMC-HVDC using existing software takes a long time due to the presence of a large number of states and non-linear...
In this work the spatial electro-thermal modeling of power electronic modules is discussed. It is shown how physical and mathematical modeling techniques can be combined to obtain a compact time efficient electro-thermal simulation framework for power electronic modules. The framework can be used to evaluate the transient temperature distribution of a power module in an electric vehicle over driving...
In this paper, a fast finite element (FE)-based method for the calculation of eddy current losses in the stator windings of randomly wound electric machines with a focus on fractional slot concentrated winding (FSCW) permanent magnet (PM) machines will be presented. The method is particularly suitable for implementation in large-scale design optimization algorithms where a qualitative characterization...
This paper aims to compare different methods for the computation of the iron losses. First of all, a brief recall on iron losses models is considered. In particular, Bertotti's formula, a homogenization technique and a vectorized Jiles-Atherton model are implemented. Afterwards, the adopted methods are validated considering an iron ring and an inset PM synchronous machine. A comparison between experimental...
Switched power systems are inherently difficult to simulate, due to the significant sensitivity of the simulation algorithm to the timing of the switching events as well as the potentially complex dynamics of the components. Numerical simulation techniques, while flexible, are not well suited for large time scale simulation of such systems. Methods for increasing the accuracy of numerical simulation...
This paper proposes a numerical approach for the determination of convective heat transfer coefficients in the end region of a totally enclosed permanent magnet synchronous machine used as an integrated starter generator in a hybrid vehicle. A simplified numerical model based on CFD methods is developed to understand the mechanism of convective heat transfer over a large operation range. The effect...
The stringent requirements on both the control bandwidth and the supply standby current make it tough to design the IC controllers for the v-core converters in future computer applications. The effects of the non-ideal characteristics of the finite gain-bandwidth product and non-zero output impedance of an operational amplifier (OP) are investigated for such a purpose. The results show surprising...
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