scholarly journals A Review of Modular Multilevel Converters for Stationary Applications

2020 ◽  
Vol 10 (21) ◽  
pp. 7719
Author(s):  
Yang Wang ◽  
Ahmet Aksoz ◽  
Thomas Geury ◽  
Salih Baris Ozturk ◽  
Omer Cihan Kivanc ◽  
...  
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Current Control ◽  
Switching Frequency ◽  
Power Losses ◽  
Circulating Current ◽  
High Switching Frequency ◽  
Wide Range ◽  
Balancing Control

A modular multilevel converter (MMC) is an advanced voltage source converter applicable to a wide range of medium and high-voltage applications. It has competitive advantages such as quality output performance, high modularity, simple scalability, and low voltage and current rating demand for the power switches. Remarkable studies have been carried out regarding its topology, control, and operation. The main purpose of this review is to present the current state of the art of the MMC technology and to offer a better understanding of its operation and control for stationary applications. In this study, the MMC configuration is presented regarding its conventional and advanced submodule (SM) and overall topologies. The mathematical modeling, output voltage, and current control under different grid conditions, submodule balancing control, circulating current control, and modulation methods are discussed to provide the state of the MMC technology. The challenges linked to the MMC are associated with submodule balancing control, circulating current control, control complexity, and transient performance. Advanced nonlinear and predictable control strategies are expected to improve the MMC control and performance in comparison with conventional control methods. Finally, the power losses associated with the advanced wide bandgap (WBG) power devices (such as SiC, GaN) are explored by using different modulation schemes and switching frequencies. The results indicate that although the phase-shifted carrier-based pulse width modulation (PSC-PWM) has higher power losses, it outputs a better quality voltage with lower total harmonic distortion (THD) in comparison with phase-disposition pulse width modulation (PD-PWM) and sampled average modulation pulse width modulation (SAM-PWM). In addition, WBG switches such as silicon carbide (SiC) and gallium nitride (GaN) devices have lower power losses and higher efficiency, especially at high switching frequency in the MMC applications.

scholarly journals Power Loss Analysis in 15 Level Asymmetric Reduced Switch Inverter Using PLECS Thermal Model & SIMULINK Precise Models

2021 ◽  
Vol 54 (1) ◽  
pp. 73-84
Author(s):  
Gireesh Kumar Devineni ◽  
Aman Ganesh ◽  
Neerudi Bhoopal
Keyword(s):  
Pulse Width ◽  
Power Loss ◽  
Thermal Model ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Switching Frequency ◽  
Power Losses ◽  
Loss Assessment ◽  
Switching Losses ◽  
High Switching Frequency

Power losses are the most critical metrics in power converters analysis and has a significant impact on economic and technological assessments due to its sufficient approximation. This article aims to prove that the power losses (Switching & Conduction losses) are very low in low frequency switching modulation in contrast with high switching frequency modulation. Two switching modulation techniques Phase Disposition (PD-multi carrier-based pulse width modulation at high switching frequency) and Selective Harmonic Elimination Pulse Width Modulation (SHEPWM-fundamental switching frequency) are considered for the power loss assessment in 15-level reduced switch asymmetric multi-level inverter. This work proposed a simplified model for calculation of switching losses in multilevel inverters using MATAB SIMULINK. Further, the thermal model of the proposed inverter is implemented on PLECS for analyzing the power losses. The comparative analysis of switching and conduction losses of the proposed inverter with the PLECS thermal model and MATLAB precise models are integral part of this research.

Integrated DC-AC and AC-DC converter using H-converter for wide range voltage applications

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saravanan R. ◽  
Vijayshankar S. ◽  
Sathyaseelan Sathyaseelan ◽  
Suresh K.
Keyword(s):  
Pulse Width ◽  
Power Loss ◽  
Pulse Width Modulation ◽  
Modulation Scheme ◽  
Power Losses ◽  
Content Type ◽  
One Stage ◽  
Energy Storage Application ◽  
Wide Range ◽  
Zero Sequence

Purpose This paper aims to propose Hidden Converter (H-Converter) combined with dual port 3Ø inverter for energy storage application to produce wide range of voltage. Some of the application required wide range of voltages, but problem from E-chopper is either boost or buck mode of operations, both modes are not possible. To overcome this drawback, H-Converter is combined with dual port 3Ø inverter controlled by carrier-based pulse width modulation (CB-PWM) technique is added with zero sequence injection. Design/methodology/approach Hidden converter is a bidirectional DC-DC chopper used to convert fixed DC to variable DC and vice versa in both buck and boost modes of operations. Dual port inverter is combined with hidden DC-DC converter can produce wide range of voltages. Findings The bidirectional DC-AC converter requires less power for processing and consumes less power losses by using modest carrier built- pulse width modulation scheme through proposed zero structure addition. Originality/value By using this proposed strategy H-Converter can produce wide range of voltage in both the sides and mostly power is processed in the 3Ø inverter with a one stage conversion with less power loss. As a result, with one stage power conversion has more efficiency because of less power loss. This proposed converter has designed by analysis, and the real time result is tested in an experiment.

scholarly journals Hybrid Pulse Width Modulation Strategy of a High-Frequency Link Three-Phase Four-Leg Matrix Converter Based on Compensation Theory

2019 ◽  
Vol 10 (1) ◽  
pp. 39
Author(s):  
Rutian Wang ◽  
Fuxu Wang ◽  
Haining Pan ◽  
Sutong Liu
Keyword(s):  
High Frequency ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Matrix Converter ◽  
Compensation Method ◽  
Switching Frequency ◽  
Control Logic ◽  
Compensation Strategy ◽  
High Switching Frequency ◽  
Three Phase

A high-frequency link (HFL) three-phase four-leg matrix converter (MC) can output three-phase balanced voltage for unbalanced load conditions. It is an inverter with great development potential. This paper presents a hybrid pulse width modulation (HPWM) strategy for a four-wire matrix converter based on the fourth bridge leg compensation method. Firstly, the rear-stage topology of a high-frequency link three-phase four-leg matrix converter is decoupled into two sets of ordinary three-phase four-wire inverters. Then the compensation strategy is applied to separate the fourth bridge leg from the coupling of the ordinary inverter and realize its independent control. Under the theory of compensation, the fourth bridge leg plays a role in compensating the deviation of the neutral point potential when the load is unbalanced, the fourth bridge leg does not need to work when the load is balanced. Finally, the fourth bridge leg modulation wave obtained by the compensation method is combined with the front three bridge leg modulation waves to perform the coupling control using the hybrid pulse width modulation strategy. It has changed the problem that the previous hybrid pulse width modulation strategy cannot be directly applied to the four-wire matrix converter. This strategy is simple to control, without adding any auxiliary commutation detection circuitry, can effectively solve the inherent commutation problem in the bidirectional switch tube of the four-wire matrix converter. It simplifies the complexity of the system, reduced control cost, and high switching loss caused by high switching frequency. The fast adjustment function of compensation strategy makes the dynamic response performance of system under load fluctuation state more prominent, the harmonic distortion rate is smaller. The perfect combination of two strategies allows the high-frequency link three-phase four-leg matrix converter with any form of load to give full play to its structural advantages. The related work verifies the feasibility and effectiveness of the modulation method and control logic.

scholarly journals Evaluation of Medium Voltage Network for Propagation of Supraharmonics Resonance

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1093
Author(s):  
Shimi Sudha Letha ◽  
Angela Espin Delgado ◽  
Sarah K. Rönnberg ◽  
Math H. J. Bollen
Keyword(s):  
Wind Farm ◽  
Low Voltage ◽  
Electrical Network ◽  
Switching Frequency ◽  
Power Sources ◽  
Transfer Impedance ◽  
Medium Voltage ◽  
High Switching Frequency ◽  
Wide Range ◽  
The Impact

Power converters with high switching frequency used to integrate renewable power sources to medium and low voltage networks are sources of emission in the supraharmonic range (2 to 150 kHz). When such converters are connected to a medium voltage (MV) network these supraharmonics propagate through the MV network and can impact network and customer equipment over a wide range. This paper evaluates an existing Swedish MV electrical network and studies the pattern of supraharmonic resonance and the propagation of supraharmonics. The MV network consists of eight feeders including a small wind farm. Simulations reveal that, the bigger the MV network, the more resonant frequencies, but also the lower the amplitude of the resonance peaks in the driving point impedance. It was also identified that for short feeders as length increases, the magnitude of the transfer impedance at supraharmonic frequency decreases. For further increment in feeder length, the magnitude increases or becomes almost constant. For very long feeders, the transfer impedance further starts decreasing. The eight feeders in the network under study are similar but show completely different impedance versus frequency characteristics. Measurements at the MV side of the wind farm show time varying emissions in the supraharmonic range during low power production. The impact of these emissions coupled with system resonance is examined.

A Low Cost MCU Based Single Phase Sinusoidal Pulse-Width-Modulated Inverter

2014 ◽  
Vol 1014 ◽  
pp. 241-244
Author(s):  
Peng Lai Chen ◽  
Chun Yu Lin ◽  
Yu Lin Juan ◽  
Te Chau Chen ◽  
Chin Sung Lin
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Cost ◽  
Harmonic Distortion ◽  
Load Resistance ◽  
Sine Wave ◽  
Switching Frequency ◽  
Single Chip ◽  
High Switching Frequency ◽  
Sampling Points

Sinusoidal pulse width modulation (SPWM) technique has been widely used in inverters and motor driver ciruits. In this paper, SPWM was generated by a low cost HT66F50 single-chip, wherein the reduced sampling points of a sine wave, and the fewer sampling points were then used to produce SPWM singals. The full-bridge inverter was modulated by the high switching frequency SPWM for the high side switches and the 60Hz control signals for the low side switches. Thus, it not only reduces the required memory spacein MCU, but also reduces the switching power losses. When the SPWM frequency is 19.53 kHz or 11.72 kHz, the total harmonic distortion (THD) of the inverter’s output is less than 0.6% under the load resistance 50, which is in compliance with the specification of IEEE STD. 519-1992.

scholarly journals Insulation Life Span of Low-Voltage Electric Motors—A Survey

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1738
Author(s):  
Vanessa Neves Höpner ◽  
Volmir Eugênio Wilhelm
Keyword(s):  
Life Span ◽  
Electric Motor ◽  
Low Voltage ◽  
Frequency Converter ◽  
Rate Of Change ◽  
High Rate ◽  
Switching Frequency ◽  
Electric Motors ◽  
Frequency Converters ◽  
High Switching Frequency

The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

A Novel Soft Switching Based Fuzzy Logic Control for Single Phase Inverter

2014 ◽  
Vol 573 ◽  
pp. 143-149
Author(s):  
N. Ismayil Kani ◽  
B.V. Manikandan ◽  
Prabakar Perciyal
Keyword(s):  
Fuzzy Logic ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Soft Switching ◽  
Switching Frequency ◽  
Pwm Inverter ◽  
Zero Voltage Switching ◽  
Control Scheme ◽  
Zero Voltage ◽  
Voltage Switching

—This The Pulse Width Modulation (PWM) DC-to-AC inverter has been widely used in many applications due to its circuit simplicity and rugged control scheme. It is however driven by a hard-switching pulse width modulation (PWM) inverter, which has low switching frequency, high switching loss, high electro-magnetic interference (EMI), high acoustic noise and low efficiency, etc. To solve these problems of the hard-switching inverter, many soft-switching inverters have been designed in the past. Unfortunately, high device voltage stress, large dc link voltage ripples, complex control scheme and so on are noticed in the existing soft-switching inverters. This proposed work overcomes the above problems with simple circuit topology and all switches work in zero-voltage switching condition. Comparative analysis between conventional open loop, PI and fuzzy logic based soft switching inverter is also presented and discussed. Keywords—Zero voltage switching, Inverter, Dc link, PI controller, Fuzzy logic system control ,Modulation strategy, Soft switching

Improved Switching Characteristics Obtained by Using High-k Dielectric Layers in 4H-SiC IGBT: Physics-Based Simulation

2017 ◽  
Vol 897 ◽  
pp. 571-574 ◽  
Author(s):  
Vidya Naidu ◽  
Sivaprasad Kotamraju
Keyword(s):  
Switching Frequency ◽  
Power Losses ◽  
Switching Power ◽  
Mos Devices ◽  
High K ◽  
High Switching Frequency ◽  
Switching Characteristics ◽  
High K Dielectric ◽  
Current Duration ◽  
Physics Based Simulation

Silicon Carbide (SiC) based MOS devices are one of the promising devices for high temperature, high switching frequency and high power applications. In this paper, the static and dynamic characteristics of an asymmetric trench gate SiC IGBT with high-k dielectrics- HfO2 and ZrO2 are investigated. SiC IGBT with HfO2 and ZrO2 exhibited higher forward transconductance ratio and lower threshold voltage compared to conventionally used SiO2. In addition, lower switching power losses have been observed in the case of high-k dielectrics due to reduced tail current duration.

A high-power PCCM LED driver based on GaN eHEMT with hybrid dimming modes

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xixian Lin ◽  
Yuming Zhang ◽  
Yimeng Zhang ◽  
Guangjian Rong
Keyword(s):  
Printed Circuit Board ◽  
Pulse Width Modulation ◽  
Circuit Board ◽  
Switching Frequency ◽  
Led Driver ◽  
Power Circuit ◽  
Content Type ◽  
Wide Range ◽  
Circuit Function ◽  
Pwm Dimming

Purpose The purpose of this study is to design a more flexible and larger range of the dimming circuit that achieves the independence of multiple LED strings drive and can time-multiplex the power circuit. Design/methodology/approach The state-space method is used to model the BUCK circuit working in Pseudo continuous conduction mode, analyze the frequency characteristics of the system transfer function and design the compensation network. Build a simulation platform on the Orcad PSPICE platform and verify the function of the designed circuit through the simulation results. Use Altium Designer 16 to draw the printed circuit board, complete the welding of various components and use the oscilloscope, direct current (DC) power supply and a signal generator to verify the circuit function. Findings A prototype of the proposed LED driver is fabricated and tested. The measurement results show that the switching frequency can be increased to 1 MHz, Power inductance is 2.2 µH, which is smaller than current research. The dimming ratio can be set from 10% to 100%. The proposed LED driver can output more than 48 W and achieve a peak conversion efficiency of 91%. Originality/value The proposed LED driver adopts pulse width modulation (PWM) dimming at a lower dimming ratio and adopts DC dimming at a larger dimming ratio to realize switching PWM dimming to analog dimming. The control strategy can be more precise and have a wide range of dimming.

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