scholarly journals Capacitor Voltage Balancing with Online Controller Performance-Based Tuning for a Switch-Sharing-Based Multilevel Inverter

2021 ◽  
Vol 11 (10) ◽  
pp. 4428
Author(s):  
Zalifah Ramli ◽  
Jafferi Jamaludin ◽  
Nasrudin Abd Rahim ◽  
Saaidal Razalli Azzuhri
Keyword(s):  
Harmonic Distortion ◽  
Input Voltage ◽  
Ideal Condition ◽  
Actual Measurement ◽  
Voltage Balancing ◽  
Tuning Mechanism ◽  
High Modulation ◽  
Output Quality ◽  
Capacitor Voltage ◽  
Online Tuning

Switch-sharing-based multilevel inverters offer great advantages in terms of efficiency improvement and output quality enhancement for low-power photovoltaic (PV) applications. However, the capacitor voltage balancing issue may critically deteriorate the output voltages, and thus could nullify the aforementioned benefits. Hence, this paper proposes a capacitor voltage balancing solution based on a buck-boost converter with performance-based tuning controllers to address the issue. The proposed controllers are designed based on the proportional-integral (PI) configuration equipped with an online tuning mechanism. The main purpose of the online tuning mechanism is to fine tune the proportional gain according to the DC input voltage, based on the measured output current total harmonic distortion (THD) performance of the inverter, while at the same time preventing the controller from reaching a state of saturation. By using the actual measurement of current THD performance, online tuning accuracy can be improved since no ideal condition is assumed, and thus, the associated error can be minimized. Simulation and experimental results reveal that the capacitor voltages can be balanced at high modulation indexes with improved current harmonic performance able to be be acquired at the inverter’s output.

scholarly journals A Modified Switch-Mode Rectifier for Wide Range of Load Variations

2013 ◽  
pp. 28-30
Author(s):  
R. N. Pradhan ◽  
S. Behera ◽  
P. K. Modi
Keyword(s):  
Mixed Mode ◽  
Harmonic Distortion ◽  
Current Mode ◽  
Input Voltage ◽  
Resistive Load ◽  
Mode Operation ◽  
Prime Concern ◽  
Wide Range ◽  
Sinusoidal Input ◽  
Capacitor Voltage

The conventional rectifier [1] which is popularly referred as Unity Power Rectifiers (UPR)/ Boost rectifier (BR) suffers from various limitations such as low power factor, high ripple content on load voltage and increase in harmonic contents in source current due to non-linear load current that results in significant increase of total harmonic distortion (THD). The main objective of conventional SMR (i.e. shown in Fig.1) is to eliminate these problems so as to maintain unity pf, sinusoidal input current, constant dc voltage and restricted harmonic distortion based on IEEE std. To avoid the separate operation for discontinuous current mode (DCM) and continuous current mode (CCM), a mixed-mode operation [2] is proposed for wide-range of load variation. Since the ripple content on output capacitor voltage and harmonic contents in input ac current are prime concern, the authors [3] presented a robust technique to get rid of these problems. In SMR, the power flow is unidirectional and the circuit is to be operated as boost switch which enables the capacitor to keep the voltage slightly greater than peak of source voltage. But in order to double the level of capacitor voltage with respect to input voltage, a new topology [4] is proposed by Y.Neba and et.al. All these SMRs operate for resistive load, but Patil and et.al[5] changed this resistive load to induction motor to study its effect upon SMR. The mixed-mode operation [2], which has some limitations, has been overcome by modifying the SMR [6]. The topologies used [1-8] use boost inductor on dc side. So this suffers from following demerits.

scholarly journals Performance Evaluation of Multicarrier Based Techniques for Single Phase Hybrid Multilevel Inverter using Reduced Switches

2017 ◽  
Vol 7 (3) ◽  
pp. 676
Author(s):  
Nunsavath Susheela ◽  
P. Satish Kumar
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Harmonic Distortion ◽  
Low Frequency ◽  
Multilevel Inverter ◽  
Voltage Balancing ◽  
Multilevel Inverters ◽  
Capacitor Voltage ◽  
Sinusoidal Pulse Width Modulation

The multilevel inverters are very popular in high power high voltage applications. However the multilevel inverters has some demerits such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem. The hybrid multilevel inverter presented in this paper has superior characteristics over conventional multilevel inverters. The hybrid multilevel inverter employs fewer components and less carrier signals when compared to conventional multilevel inverters. It consists of level generation and polarity generation stages which involves high frequency and low frequency switches. The complexity and overall cost for higher output voltage levels are greatly reduced. Implementation of single phase 7-level, 9-level and 11-level hybrid multilevel inverter has been performed using sinusoidal pulse width modulation (SPWM) strategies i.e., phase disposition (PD), alternate phase opposition disposition (APOD) and carrier overlapping (CO). Also the three techniques are compared in terms of total harmonic distortion (THD) for various modulation indices and observed to be greatly improved when compared to conventional topologies. The performance of single phase eleven level hybrid inverter is analyzed for different loads.  Simulation is performed using MATLAB/ Simulink.

A Novel Capacitor-Voltage Balancing Strategy for Double-Y STATCOM Under Unbalanced Operations

2021 ◽  
pp. 1-1
Author(s):  
Ehsan Behrouzian ◽  
Massimo Bongiorno ◽  
Jan R. Svensson ◽  
Aravind Mohanaveeramani
Keyword(s):  
Voltage Balancing ◽  
Capacitor Voltage
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