1,721,065 research outputs found
Automated and scalable optimal control of three-Phase embedded power grids including PLL
No full textEmbedded grids have been increasingly adopted into applications such as More Electric Aircraft where different power converters are interconnected to each other. Interactions between the grid components poses the risk of instability to the system, more so when in the presence of reduced passive filters. An approach of automated and scalable tuning of such embedded grids with consideration for the dynamics introduced by a PLL is presented in this paper. A structured state feedback optimal control approach is proposed which enables a controller to be synthesised is such a way that maximum performance of the grid can be achieved, whilst guaranteeing power converter synchronisation to the grid, and avoiding instability due to converter interaction, and PLL dynamics. © 2017 IEEE
The design of a position-based repetitive control for speed ripple reduction in PMLSMs
No full text\ua9 2017 IEEE. Periodic speed errors can occur in permanent magnet linear synchronous machines for two reasons: 1) a periodic reference signal; 2) cogging force and friction. For reducing such periodic errors, iterative learning control or repetitive control approaches, used in conjunction with more common control actions, can be strongly effective. However, the design of the stability filter, robustness filter and other parameters for a traditional repetitive controller can be a complex task and may need to be adjusted when the frequency of such periodic error varies. Existing solutions tend to develop more adaptive tuning methods for repetitive controller to enhance the whole control system. This paper shows that the performance of a traditional speed loop can be enhanced with a repetitive controller without complicating the tuning of the repetitive controller. Consequently, a position-based repetitive control combined with deadbeat current control method is proposed. Simulation results show that the proposed method is effective for reducing speed ripple at difference frequencies without necessarily adjusting its parameters
Design of a repetitive controller as a feed-forward disturbance observer
No full text\ua9 2016 IEEE. From the structure point of view, a repetitive controller (RC) is considerably similar to a disturbance observer. By adding a correction term to the traditional RC and considering the disturbances as states, the repetitive controller can be designed in the same way as a disturbance observer. This paper presents therefore a new simple way of tuning a repetitive controller. Simulations show that, when compared with the traditional RC, the proposed RC configuration can achieve greater stability margin. As opposed to the traditional plug-in RC, the new RC structure studied in this paper is also shown to be robust against variations in the inner loop delays if it is used in a cascaded configuration. The immunity to plant parameter variations is another added benefit of the proposed controller
Parameters and Volt-Ampere Ratings of a Floating Capacitor Open-End Winding Synchronous Motor Drive for Extended CPSR
No full textThis article proposes an analytical method for the selection of machine parameters and inverter power ratings of a synchronous motor operated in an open-end winding (OEW) configuration with one of the two voltage-source inverters (VSIs) connected to a floating capacitor (FC) in order to meet a specific torque-speed profile. With the derived normalized expressions and curves, all the suitable synchronous motors operated with an OEW-FC and a standard two-level VSI drive can be easily compared according to the power rating and desired speed-torque characteristic
Identification of Linear Permanent Magnet Synchronous Motor Parameters and Inverter Non-Linearity Effects
No full text\ua9 2018 IEEE. The paper presents an automatic parameter identification procedure for linear permanent magnet synchronous motors. The electrical parameters of a test machine are estimated by identification tests performed through the inverter. The method employs the available feedback signals that are needed by the control. The stator resistance and machine inductances are estimated through signal injection at standstill. The permanent magnets\u27 flux-linkage identification instead requires carriage movement. Subsequently, the inverter nonlinearity characteristics are identified, again at standstill, through a flux-observer. The proposed self-commissioning process requires only the nameplate data of the machine and no datasheet information of the power electronic devices is needed. The developed techniques can be used both with and without a position sensor. The complete process is automatic and safe to run on its own and requires least intervention from the operator
Particle Swarm Optimization Tuning of Modular Multilevel Converters in a Time-Invariant Framework
No full textThis work investigates the Particle Swarm Optimization (PSO) algorithm as a tool to tune the control parameters of a Modular Multilevel Converter (MMC) in a single-terminal HVdc configuration. More precisely, due to its inherent capacity of handling system non-linearities, the PSO algorithm is used to tune a nonlinear control structure based on passivity arguments capable of ensuring global asymptotic stability of the converter. This nonlinear control strategy was successfully applied to the MMC in previous efforts, albeit with sub-optimal tuning, and therefore below par performance. Thus, this work aims to contribute to the state of the art by proving that system performance under the nonlinear control structure of interest can be further improved via PSO-tuning. Finally, to reduce the computational burden, we propose to apply the PSO algorithm directly to a recent state-space representation of an MMC with a constant equilibrium point. © 2019 IEEE
AC-DC Isolated Matrix Converter Charger: Topology and Modulation
No full textThis paper presents the modulation strategy for the 25 kW AC-DC isolated Matrix Charger three-phase rectifier (MCharger). The proposed topology allows current and voltage regulation for energy storage devices such as EVs batteries. Compared to a standard Dual-Active-Bridge topology, the Matrix converter allows to directly perform an AC-AC energy conversion thus eliminating the rectifying stage. A high frequency (HF) voltage waveform is generated to feed the isolation transformer, which is characterized by an almost negligible leakage inductance, allowing for the reduction of the transformer voltage drops. The rectification of the ac-waveform is achieved at the output stage, consisting of an H-bridge and an LC filter. The suggested topology powered with the proposed modulation is able to provide a wide output voltage range which can vary from 50 V to 500 V, providing up to a maximum power of 25 kW allowed for level I chargers. © 2020 IEEE
Controller Design of an Active Front-End Converter Keeping in Consideration Grid Dynamic Interaction
No full textThis article presents a systematic control
design procedure for an active front-end (AFE) converter
connected to a power electronics embedded grid. A parametric model of the grid is first identified using the AFE
itself to excite the system. This model is then integrated
with the AFE one in order to obtain a global system representation. Subsequently, a globally optimized local controller is synthesized for the AFE keeping in consideration
the interaction between the converter and the grid. The
proposed method is finally tested experimentally, and its
performance is compared with a traditional proportional–
integral controller in a dq synchronous reference fram
Model Predictive Control of a Double Input Bidirectional Boost DC-DC Converter
No full textThis paper presents a new model predictive control strategy for a boost dc-dc converter with two input sources and one output. The converter has three controllable switches and is designed for high efficiency in low and high load conditions. The proposed MPC strategy defines target values for controlled currents and applies the appropriate duty cycles to reach them. Its effectiveness is demonstrated by simulation results in a Matlab/Simulink environment
Open-Circuit Fault Tolerant Study of Bearingless Multi-Sector Permanent Magnet Machines
No full textThis paper presents a fault tolerant study of a multiphase sectored permanent magnet synchronous machine involving a tripel three-phase winding. The machine electro-megnetic model is written in a general way so that it can be extended and applied to all machines with a similar winding structure. An expression of the d-q axis reference currents of each three-phase winding as a function of the x - y force components and torque is provided taking into acccunt the Joule losses minimization. Then, the case of open-circuit of one winding sector is considered, the model of the faulty machine derived and an expression of the new reference currents needed to generate radial suspension force and motoring torque is written.Finally, the theoretical analysis are validated through finite elements simulations and the levitation performance of the machine considered are evaluated in the Matlab-Simulink environment in the case of one sector fault per time
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