Single phase inverter system using proportional resonant current control

This paper presents the harmonic reduction performance of proportional resonant (PR) current controller in single phase inverter system connected to nonlinear load. In the study, proportional resonant current controller and low pass filter is discussed to eliminate low order harmonics injection in single phase inverter system. The potential of nonlinear load in producing harmonics is showed and identified by developing a nonlinear load model using a full bridge rectifier circuit. The modelling and simulation is done in MATLAB Simulink while harmonic spectrum results are obtained using Fast Fourier Transfor. End result show PR current controller capability to overcome the injection of current harmonic problems thus improved the overall total harmonic distortion (THD)

A low‐noise high‐speed diode laser current controller

We describe a new diode laser current controller which features low current noise, excellent dc stability, and the capacity for high‐speed modulation. While it is simple and inexpensive to construct, the controller compares favorably with the best presently available commercial diode laser current controllers

A Digital Internal Model Current Controller for Salient Machines

The performance of anisotropic electrical machines is strongly dependent on the current loop characteristics. The problems for achieving robustness and fast response, without overshoot and oscillations, are mainly related to different values and behaviour of the direct and quadrature inductances (Ld, Lq), as well as to high output frequencies. In this paper, a novel current controller structure based on Internal Model Control (IMC) method is presented, taking into account the magnetic anisotropy (Ld != Lq). The model of salient machines is derived directly in the discrete domain and used to obtain a model-based controller. The controller derivation does not rely on transport-delay approximations, which enables improved decoupling of axes dynamics and the closed-loop robustness for very high output frequencies. The presented controller enables enhanced response for higher current loop bandwidth and output frequencies than the state-of-the-art methods. The experimental verification is performed on a 3-phase synchronous machine, using a standard industrial 3-phase inverter

Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters

The integration of AC-DC power converters to manage the connection of generation to the grid has increased exponentially over the last years. PV or wind generation plants are one of the main applications showing this trend. High power converters are increasingly installed for integrating the renewables in a larger scale. The control design for these converters becomes more challenging due to the reduced control bandwidth and increased complexity in the grid connection filter. A generalized and optimized control tuning approach for converters becomes more favored. This paper proposes an algorithm for estimating the dynamic performance of the stationary frame current controllers, and based on it a generalized and optimized tuning approach is developed. The experience-based specifications of the tuning inputs are not necessary through the tuning approach. Simulation and experimental results in different scenarios are shown to evaluate the proposal.Peer ReviewedPostprint (published version

New design of the LED current controller

In the work traditional and innovative methods for constant current LED drivers have been studied. The low-cost solutions for energy effective low lighting flicker current regulation have been proposed. The advantage is due to fact that auxiliary switch-mode regulator converts only small part of output power. The proposed solution can be used in LED drivers to reduce pulsations of the light flux, as well as in driverless AC LED modules to monitor LED currents and/for power correction

Implementing SVPWM Technique to an Axial Flux Permanent Magnet Synchronous Motor Drive with Internal Model Current Controller

This paper presents a study of axial flux permanent magnet synchronous motor (AFPMSM) drive system. An internal model control (IMC) strategy is introduced to control the AFPMSM drive through currents, leading to an extension of PI control with integrators added in the off-diagonal elements to remove the cross-coupling effects between the applied voltages and stator currents in a feed-forward manner. The reference voltage is applied through a space vector pulse width modulation (SVPWM) unit. A diverse set of test scenarios has been realized to comparatively evaluate the state estimation of the sensor-less AFPMSM drive performances under the implemented IMCbased control regime using a SVPWM inverter. The resulting MATLAB simulation outcomes in the face of no-load, nominal load and speed reversal clearly illustrate the well-behaved performances of IMC controller and SVPWM technique to an Axial Flux PM Motor Drive system

Optimal controller gains for inner current controllers in VSC inverters

The standard method for controlling an IGBT inverter (or any VSC inverter for that matter) is by vector current control. This control system consists of two cascaded control loops. One possible realisation of the outer controller is to control the DC bus voltage such that no more power is taken off the DC bus than is available. This creates a current reference, which is fed into the inner current controller. The inner current controller then regulates the current passing through the IGBT such that the desired power is dispatched onto the grid. Whilst most research treats the grid connection as a simple RL circuit, there is little consistency on the method by which the gains of the inner current controller are selected. Internal model control, modulus optimum and root locus methods are just a few of the methods used to find the gains. However, it is not clear which of these methods yields the best performance of the inner current controller. This work suggests that tuning on phase margin or manually tuning may not achieve the best results

Simulation of a single-phase active power filter based ANN controller

This project presents the employment of a single-phase active power filter (APF) to compensate harmonics generated by battery charger. The presence of the harmonics leads to various problems and poor power quality. The objectives of this project are to reduce the harmonic distortion and improve the power factor of the single-phase system with battery charger load. The operation of APF is verified using the simulations in Matlab/Simulink. Artificial neural network (ANN) control based shunt APF is compared to proportional-integral (PI) controller in order to regulate the DC-bus voltage and hysteresis current controller is employed to generate signal for switching purpose. The process is based on sensing line voltages, line currents, filter currents and DC side capacitor voltage. The error signal caused by the filter has been computed firstly. Then this error signal has been compensated using the controller and generates reference line current. The reference filter currents signal then obtained by subtracts the reference line current with the load current. This reference filter current is feed to the hysteresis current controller and compare with the sensed filter currents to obtain the switching signal for active power filter. Simulation results show that the ANN controller based shunt APF has better performance which has reduced harmonic distortion and improve system performance compared to the use of conventional PI controller. Keywords: Shunt APF, PI controller, ANN controller, Total Harmonic Distortion (THD