Optimized Design of Double-Loops Controller for Single-Phase Pulse Rectifier without LC Resonant Filter Circuit

2014 ◽  
Vol 1061-1062 ◽  
pp. 1031-1038
Author(s):  
Wen Ming Zhang ◽  
Yong Xin Li ◽  
Xing Lai Ge ◽  
Yang Lu

Research on the lightweight issue of DC-link is an important direction in modern AC drive electric locomotive. Canceling LC filter circuit is an important way to achieve the goal of lightweight. Therefore, this paper focuses on single-phase pulse rectifier without LC filter circuit. The generation mechanism of DC voltage ripple and network-side current harmonics in grid-side converter is derived. Then, aiming to eliminate the current harmonics, the N-order notch filter and PR controller are introduced to the double-loops controller. The loop of voltage outer controller with N-order notch filter can filter out the ripple of DC-side voltage effectively without affecting the dynamic performance of the controller system. Meanwhile, the loop of current inner controller with PR controller can achieve zero steady-state error control to both the fundamental and harmonic current, and can suppress the low order harmonics in the line current effectively. Analysis shows that replacing the original L2C2 filter circuit with software controller is feasible. Finally, the validity and effectiveness of the proposed scheme are verified in computer simulation.

Author(s):  
Kamrul Hasan ◽  
Muhammad Murtadha Othman ◽  
Nor Farahaida Abdul Rahman ◽  
M. A. Hannan ◽  
Ismail Musirin

<p>This paper presents an analysis of a three-phase unified power quality conditioner (UPQC) in terms of design and performance. A back to back connection of a series compensator and a shunt compensator with a common DC-bus is utilized to build the UPQC model. The series compensator compensates the power quality problems such as grid voltage sags/swells for the grid side. During sag and swell condition, the compensated voltage is injected by the series compensator in phase with the point of common coupling (PCC) or out of phase with PCC. The load current harmonics is compensated by using the shunt compensator. The dynamic performance and  the steady state of the designed model are analyzed by using MATLAB-Simulink under several disturbances such as PCC voltage harmonics, voltage sags/swells and load unbalancing using a nonlinear load. </p>


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3596
Author(s):  
Chia-Ming Liang ◽  
Yi-Jen Lin ◽  
Jyun-You Chen ◽  
Guan-Ren Chen ◽  
Shih-Chin Yang

For pulse width modulation (PWM) inverter drives, an LC filter can cascade to a permanent magnet (PM) machine at inverter output to reduce PWM-reflected current harmonics. Because the LC filter causes resonance, the filter output current and voltage are required for the sensorless field-oriented control (FOC) drive. However, existing sensors and inverters are typically integrated inside commercial closed-form drives; it is not possible for these drives to obtain additional filter output signals. To resolve this integration issue, this paper proposes a sensorless LC filter state estimation using only the drive inside current sensors. The design principle of the LC filter is first introduced to remove PWM current harmonics. A dual-observer is then proposed to estimate the filter output current and voltage for the sensorless FOC drive. Compared to conventional model-based estimation, the proposed dual-observer demonstrates robust estimation performance under parameter error. The capacitor parameter error shows a negligible influence on the proposed observer estimation. The filter inductance error only affects the capacitor current estimation at high speed. The performance of the sensorless FOC drive using the proposed dual-observer is comparable to the same drive using external sensors for filter voltage and current measurement. All experiments are verified by a PM machine with only 130 μH phase inductance.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2118
Author(s):  
Elias Kaufhold ◽  
Simon Grandl ◽  
Jan Meyer ◽  
Peter Schegner

This paper introduces a new black-box approach for time domain modeling of commercially available single-phase photovoltaic (PV) inverters in low voltage networks. An artificial neural network is used as a nonlinear autoregressive exogenous model to represent the steady state behavior as well as dynamic changes of the PV inverter in the frequency range up to 2 kHz. The data for the training and the validation are generated by laboratory measurements of a commercially available inverter for low power applications, i.e., 4.6 kW. The state of the art modeling approaches are explained and the constraints are addressed. The appropriate set of data for training is proposed and the results show the suitability of the trained network as a black-box model in time domain. Such models are required, i.e., for dynamic simulations since they are able to represent the transition between two steady states, which is not possible with classical frequency-domain models (i.e., Norton models). The demonstrated results show that the trained model is able to represent the transition between two steady states and furthermore reflect the frequency coupling characteristic of the grid-side current.


2016 ◽  
Vol 78 (10-4) ◽  
Author(s):  
Amirullah Amirullah ◽  
Mochamad Ashari ◽  
Ontoseno Penangsan ◽  
Adi Soeprijanto

Randomly installed distributed generators (DGs) in households may cause unbalanced line current in a distribution network. This research presents a battery energy system for balancing of line current in a distribution network involving multi units of single phase photovoltaic (PV) distributed generators (DGs). In this paper, the PV generators were simulated consisting of a buck-boost DC/DC converter and single phase DC/AC inverter. It was connected to the distribution line through the low voltage 220 volt 50 Hz. The proposed phase balancing system uses battery energy storage and three single phase bidirectional inverters. The inverter is capable of injecting current or absorbing power from the line to the battery. This inverter operation is arranged to balance each distribution line separately, as well as to improve other power quality parameters, such as voltage and current harmonics. Simulation results show that the system was capable of improving the unbalanced line current from 15.59 % to 11, 48 % and unbalanced line voltage from 1.76 % to 0.58 %. The system was able for increasing current harmonics from 0.98 % to 1.03% and voltage harmonics from 38.96% to 39.08%.


2018 ◽  
Vol 41 (9) ◽  
pp. 2451-2464
Author(s):  
Moushumi Patowary ◽  
Gayadhar Panda ◽  
Bimal C Deka

This paper presents the collective operation and comparative assessment of artificial neural network (ANN)-based adaptive controller with detuned-inductor capacitor (LC) filter facility in grid-tied voltage source control (VSC) system. In order to facilitate proper shaping of VSC outputs and to avoid voltage surge or current surge issues that may occur during the synchronization, the controlling action should reflect importance of total impedance (Zt) effect for: (i) accurate online weight updating, (ii) generation of correct references for proper shaping of VSC outputs, (iii) accurate assessment and exclusion of current harmonics and (iv) robust in defending any system perturbation. This impedance is taken into consideration during the run-time weight updation process through extended control steps in order to pass over various losses that certainly occurs in transformers, filters, line parameters and so forth. Performance of the system is well improved with an inclusion of total impedance (Zt) measured between the VSC and point of common coupling (PCC). A detuned-LC filter is predominantly intended for reactive power compensation, power factor correction, prompt and accurate alleviation of the harmonics. A comparative assessment in between enhanced and conventional adaptive controllers that are designed in MATLAB/Simulink clarifies the robust performances of the proposed control design under sundry system turbulences. The verification of the proposed enhanced controller is approved with the hardware results obtained using dSPACE RTI 1202 kit.


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