Voltage Ripple Reduction in Voltage Loop of Voltage Source Converter

Author(s):  
Jedsada Jaroenkiattrai ◽  
Viboon Chunkag

In order to achieve a good dynamical response of a full-bridge AC-DC voltage source converters (VSC). The bandwidth of PI controller must be relatively wide. This leads to the voltage ripple produced in the control signal, as known that its ripple frequency has twice of the line frequency and cause the 3rd harmonic of an input current. A Ripple Voltage Estimator (RVE) algorithm and Feed-Forward Compensation (FFC) algorithm are proposed and added to the conventional control. The RVE algorithm estimated the ripple signal to subtract it occurring in the voltage loop. As a result, the 3rd harmonic of the input current can be reduced, and hence the Total Harmonic Distortion of input current (THDi) are improved.  In addition, the FFC algorithm will offer a better dynamical response of output voltage. The performance evaluation was conducted through the simulation and experiment at 110Vrms/50Hz of the input voltage, with a 600 W load and 250 V<sub>dc</sub> output voltage. The overall system performances are obtained as follows: the power factor at the full load is higher 0.98, the harmonic distortion at AC input power source of the converter is under control in IEC61000-3-2 class A limit, and the overall efficiency is greater than 85%.

2018 ◽  
Vol 7 (4.30) ◽  
pp. 240 ◽  
Author(s):  
M. K. R. Noor ◽  
A. Ponniran ◽  
M. A. Z. A. Rashid ◽  
A. A. Bakar ◽  
J. N. Jumadril ◽  
...  

This paper discusses the current total harmonic distortion (THDi) and voltage ripple minimization of SEPIC converter based on parameters design optimization. This conventional PFC SEPIC converter is designed to operate in discontinuous conduction mode in order to achieve almost unity power factor. The passive components, i.e., inductor and capacitor are designed based on switching frequency and resonant frequency. Meanwhile, the ranges of duty cycle for buck and boost operations are between 0<D<0.5 and 0.5<D<1, respectively, for the output voltage variation of the converter. The principle of the parameters design optimization is based on the balancing energy compensation between the input capacitor and output inductor. The experimental results show that, the current THD is reduced to 2.66% from 70.9% after optimization process is conducted. Furthermore, it is confirmed that the output voltage ripple frequency is always double from the input line frequency, fL = 2foutand the output voltage ripple is always lower than the maximum input voltage ripple. Therefore, the designed parameters of the experimental converter is confirmed with approximately 65 W of the converter output power.


Author(s):  
R. S. Bajpai ◽  
Amarjeet Singh

This paper deals with sliding mode control of converter and its application to distributed generation. Sliding mode control is used to control the voltage source converter in voltage or current control mode. Modeling and control of H bridge converter system using sliding mode control is proposed. Easily implemented sliding surfaces provide prominent dynamic characteristics against changes in the load and in the input voltage. Distribution static compensator (DSTATCOM) is used to control the voltage of the bus to which it is connected to a balance sinusoid in respect of the harmonic distortion in supply or load side. A variable wind turbine generator is used to produces a variable DC voltage which is placed as input voltage source to converter of DSTATCOM. A control strategy for grid voltage control using DSTATCOM in voltage control mode has been implemented in respect of the wind variation. The results are validated using PSCAD/EMTDC simulation studies.


2019 ◽  
pp. 22-29

Caracterización del método SVPWM con inversor trifásico de dos niveles Juan Tisza1, 2, Javier Villegas2 1Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Rímac, Lima Perú 2Universidad Nacional Mayor de San Marcos, Ciudad Universitaria, Lima, Perú Recibido 17 de junio del 2019, Revisado el 17 de julio de 2019 Aceptado el 19 de julio de 2019 DOI: https://doi.org/10.33017/RevECIPeru2019.0005/ Resumen Las cargas en Corriente Alterna (CA) requieren voltaje variable y frecuencia variable. Estos requisitos se cumplen con un inversor de fuente de voltaje (VSI). Se puede lograr un voltaje de salida variable variando la tensión de CC de entrada y manteniendo constante la ganancia del inversor. Por otro lado, si la tensión de entrada CC es fija y no es controlable, se puede lograr una tensión de salida variable variando la ganancia del inversor, lo que normalmente se logra mediante el control de modulación por ancho de pulso dentro del inversor. Hay varias técnicas de modulación de ancho de pulso, pero la técnica de vector espacial es una buena opción entre todas las técnicas para controlar el inversor de fuente de voltaje. La modulación por ancho de pulso de vector espacial (SVPWM) es un método avanzado y muy popular con varias ventajas tales como la utilización efectiva del bus de CC, menos generación de armónicos en voltaje de salida, menos pérdidas de conmutación, amplio rango de modulación lineal, etc. En este documento, se ha tomado un inversor de fuente de voltaje constante CC y se ha implementado la SVPWM para VSI de dos niveles utilizando MATLAB / SIMULINK. Descriptores: Modulación de ancho de pulso (PWM), modulación de ancho de pulso de vector espacial (SVPWM), distorsión armónica total (THD), inversor de fuente de voltaje (VSI). Abstract Alternating Current (AC) loads require variable voltage and variable frequency. These requirements are met by a voltage supply inverter (VSI). A variable output voltage can be achieved by varying the input DC voltage and keeping the inverter gain constant. On the other hand, if the DC input voltage is fixed and not controllable, a variable output voltage can be achieved by varying the gain of the inverter, which is normally achieved by controlling the pulse width modulation within the inverter. There are several pulse width modulation techniques, but the spatial vector technique is a good choice among all the techniques for controlling the voltage source inverter. Spatial vector pulse width modulation (SVPWM) is an advanced and very popular method with several advantages such as effective utilization of CC bus, less harmonic generation in output voltage, less switching losses, wide range of linear modulation, etc. In this document, a CC constant voltage source inverter has been taken and SVPWM has been implemented for two-level VSI using MATLAB / SIMULINK. Keywords: Pulse Width Modulation (PWM), Space Vector Pulse Width Modulation (SVPWM), Total Harmonic Distortion (THD), Voltage Source Inverter (VSI).


2020 ◽  
Vol 39 (2) ◽  
pp. 589-599
Author(s):  
D.B.N. Nnadi ◽  
S.E. Oti ◽  
C.I. Odeh

Splitting of a dc voltage source with two capacitors has been the approach in generating 5-level output voltage with single- and three-phase full-bridge circuits and added bidirectional switch. Associated with this configuration is the problem of voltage imbalance between the splitting capacitors. In addition, the inverter output voltage magnitude is obviously limited to the value of the split input voltage source. Presented in this paper is a unit topology for single-phase 5-level multilevel inverter, MLI. It simply consists of a full-bridge circuit, a capacitor, charge-discharge unit and a dc source. The charge-discharge unit with the capacitor is the interface between the full-bridge and the dc source. The proposed unit cell can generate a 5-level output voltage waveform whose peak value is twice the input voltage value. For higher output voltage level, a cascaded structure of the developed unit cell is presented. Comparing the proposed inverter with CHB inverter and some recent developed MLI topologies, it is found that the proposed inverter configuration generates higher output voltage value, at reduced component-count, than other topologies, for a specified number of dc input voltages. For two cascaded modules, simulation and experimental verifications are carried out on the proposed inverter topology for an R-L load. Keywords: Cascaded multilevel, Inverter, total harmonic distortion, topologies, waveform


Author(s):  
Akram Qashou ◽  
Sufian Yousef ◽  
Abdallah A. Smadi ◽  
Amani A. AlOmari

AbstractThe purpose of this paper is to describe the design of a Hybrid Series Active Power Filter (HSeAPF) system to improve the quality of power on three-phase power distribution grids. The system controls are comprise of Pulse Width Modulation (PWM) based on the Synchronous Reference Frame (SRF) theory, and supported by Phase Locked Loop (PLL) for generating the switching pulses to control a Voltage Source Converter (VSC). The DC link voltage is controlled by Non-Linear Sliding Mode Control (SMC) for faster response and to ensure that it is maintained at a constant value. When this voltage is compared with Proportional Integral (PI), then the improvements made can be shown. The function of HSeAPF control is to eliminate voltage fluctuations, voltage swell/sag, and prevent voltage/current harmonics are produced by both non-linear loads and small inverters connected to the distribution network. A digital Phase Locked Loop that generates frequencies and an oscillating phase-locked output signal controls the voltage. The results from the simulation indicate that the HSeAPF can effectively suppress the dynamic and harmonic reactive power compensation system. Also, the distribution network has a low Total Harmonic Distortion (< 5%), demonstrating that the designed system is efficient, which is an essential requirement when it comes to the IEEE-519 and IEC 61,000–3-6 standards.


Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 154
Author(s):  
Wei Yao ◽  
Jiamin Cui ◽  
Wenxi Yao

This paper presents a novel digital control scheme for the regulation of single-phase voltage source pulse width modulation (PWM) inverters used in AC power sources. The proposed scheme adopts two deadbeat controllers to regulate the inner current loop and the outer voltage loop of the PWM inverter. For the overhead of digital processing, the change of duty of PWM lags one carrier period behind the sampling signal, which is modeled as a first-order lag unit in a discrete domain. Based on this precise modeling, the deadbeat controllers make the inverter get a fast dynamic response, so that the inverter’s output voltage is obtained with a very low total harmonic distortion (THD), even when the load is fluctuating. The parameter sensitivity of the deadbeat control was analyzed, which shows that the proposed deadbeat control system can operate stably when the LC filter’s parameters vary within the range allowed. The experimental results of a 2kW inverter prototype show that the THD of the output voltage is less than 3% under resistive and rectifier loads, which verifies the feasibility of the proposed scheme. An additional advantage of the proposed scheme is that the parameter design of the controller can be fully programmed without the experience of a designer.


2020 ◽  
Vol 11 (4) ◽  
pp. 64 ◽  
Author(s):  
Zhengxin Liu ◽  
Jiuyu Du ◽  
Boyang Yu

Direct current to direct current (DC/DC) converters are required to have higher voltage gains in some applications for electric vehicles, high-voltage level charging systems and fuel cell electric vehicles. Therefore, it is greatly important to carry out research on high voltage gain DC/DC converters. To improve the efficiency of high voltage gain DC/DC converters and solve the problems of output voltage ripple and robustness, this paper proposes a double-boost DC/DC converter. Based on the small-signal model of the proposed converter, a double closed-loop controller with voltage–current feedback and input voltage feedforward is designed. The experimental results show that the maximum efficiency of the proposed converter exceeds 95%, and the output voltage ripple factor is 0.01. Compared with the traditional boost converter and multi-phase interleaved DC/DC converter, the proposed topology has certain advantages in terms of voltage gain, device stress, number of devices, and application of control algorithms.


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