scholarly journals Hybrid PWM Strategy for Power Efficiency Improvement of 5-Level TNPC Inverter and Current Distortion Compensation Method

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 76 ◽  
Author(s):  
Taeyeong Lee ◽  
Hanyoung Bu ◽  
Younghoon Cho
Keyword(s):  
High Frequency ◽  
Power Efficiency ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Compensation Method ◽  
Switching Frequency ◽  
Efficiency Improvement ◽  
Switching Loss ◽  
Distortion Compensation ◽  
Output Filter

This paper proposes a pulse width modulation (PWM) strategy for improving the efficiency of a 5-level H-bridge T-type neutral point clamped (TNPC) inverter. In the case of the proposed PWM strategy, unlike the conventional PWM strategy in which both of the switching legs of the H-bridge inverter operate at a high frequency, one switching leg of the inverter operates at a low frequency. As the switching frequency is lowered, the switching loss is reduced, this improving the efficiency of the system. The duty references for the switching legs and the operating principle of the inverter are described in detail. The proposed PWM strategy, however, causes distortion of the output filter inductor current. The cause of the distortion has been analyzed and a compensation method is proposed to mitigate the distortion of the current. The effect of the proposed PWM strategy can be predicted through the loss calculation of the inverter for each modulation strategy. Furthermore, current distortion mitigation obtained by compensation method is confirmed through the simulation. In order to verify the effectiveness of the proposed strategy, a 2 kW H-bridge TNPC inverter prototype is implemented and tested. The simulation and experimental results show that the efficiency of the inverter is improved when the proposed PWM strategy is applied.

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.

Analysis of Fast-Scale Bifurcation in Peak Current Controlled Buck-Boost Inverter Based on Unified Averaged Model

2016 ◽  
Vol 26 (05) ◽  
pp. 1650074 ◽  
Author(s):  
Hao Zhang ◽  
Shuai Dong ◽  
Weimin Guan ◽  
Ye Liu
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Period Doubling ◽  
Current Control ◽  
High Frequency Oscillation ◽  
Switching Frequency ◽  
Unified Framework ◽  
Frequency Oscillation ◽  
Peak Current ◽  
Averaged Model

In this paper, a unified averaged modeling method is proposed to investigate the fast-scale period-doubling bifurcation of a full-bridge integrated buck-boost inverter with peak current control. In order to increase the resolution of the conventional classic averaged model to half the switching frequency, sample-and-hold effect of inductor current is absorbed into the averaged model, i.e. the proposed unified averaged model can capture the high-frequency dynamical characteristics of the buck-boost inverter, which is both an extension and a modification of conventional averaged model. Based on the unified mode, fast-scale bifurcation is identified, and the corresponding bifurcation point is predicted with the help of the locus movement of all the poles, and their underlying mechanisms are revealed. Detailed analysis shows that the occurrence of high-frequency oscillation means fast-scale bifurcation, while the occurrence of low-frequency oscillation leads to slow-scale bifurcation. Finally, it is demonstrated that the unified averaged model can provide not only a general method to investigate both the slow- and fast-scale bifurcations in a unified framework but also a quite straightforward design-oriented method which can be directly applicable.

scholarly journals A Fractional-Order Element (FOE)-Based Approach to Wireless Power Transmission for Frequency Reduction and Output Power Quality Improvement

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1029 ◽  
Author(s):  
Guidong Zhang ◽  
Zuhong Ou ◽  
Lili Qu
Keyword(s):  
Fractional Order ◽  
High Frequency ◽  
Power Efficiency ◽  
Power Transmission ◽  
Switching Frequency ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
High Switching Frequency ◽  
Power Quality Improvement ◽  
Power Inductors

A wireless power transmission (WPT) requires high switching frequency to achieve energy transmission; however, existing switching devices cannot satisfy the requirements of high-frequency switching, and the efficiency of current WPT is too low. Compared with the traditional power inductors and capacitors, fractional-order elements (FOEs) in WPT can realize necessary functions though requiring a lower switching frequency, which leads to a more favorable high-frequency switching performance with a higher efficiency. In this study, a generalized fractional-order WPT (FO-WPT) is established, followed by a comprehensive analysis on its WPT performance and power efficiency. Through extensive simulations of typical FO wireless power domino-resonators (FO-WPDRS), the functionality of the proposed FO-WPT for medium and long-range WPT is demonstrated. The numerical results show that the proposed FOE-based WPT solution has a higher power efficiency and lower switching frequency than conventional methods.

Intelligent Control Circuit Integral with Pattern Recognition Techniques for High-Pressure Sodium Lamps

2017 ◽  
Vol 26 (07) ◽  
pp. 1750108
Author(s):  
Yuzhuo Pan ◽  
Chen Lv ◽  
Shanhe Su ◽  
Jincan Chen
Keyword(s):  
Pattern Recognition ◽  
High Pressure ◽  
Intelligent Control ◽  
High Frequency ◽  
Pulse Width Modulation ◽  
Smart Cities ◽  
Control Strategies ◽  
Low Frequency ◽  
Acoustic Resonance ◽  
Working Device

The paper presents the analysis, simulation, and experimental methods to eliminate acoustic resonance in high-frequency high-pressure sodium (HPS) lamps and integrate intelligent control strategies in the working device. Based on the pulse-width modulation (PWM) output generated by the microcontroller, the acoustic resonance in the high-frequency lamp can be successfully eliminated by modulating the high-frequency driving current via a low-frequency signal. Particularly, by implementing the pattern recognition, the control system enables the lamp to have the abilities of accurate timing, gradient dimming, automatic protection, and intellisense. The proposed model will provide useful information for designing intelligent lighting system towards smart cities.

scholarly journals Common-Mode Reduction SVPWM for Three-Phase Motor Fed by Two-Level Voltage Source Inverter

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3884
Author(s):  
Jian Zheng ◽  
Mingcheng Lyu ◽  
Shengqing Li ◽  
Qiwu Luo ◽  
Keyuan Huang
Keyword(s):  
High Frequency ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Voltage Source ◽  
Switching Frequency ◽  
Voltage Source Inverter ◽  
Large Magnitude ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Three Phase

Aiming at the problem of large magnitude and high frequency of common-mode voltage (CMV) when space vector pulse width modulation (SVPWM) is used in a three-phase motor fed by a two-level voltage source inverter, a common-mode reduction SVPWM (CMRSVPWM) is studied. In this method, six new sectors are obtained by rotating six sectors of conventional SVPWM by 30°. In odd-numbered sectors, only three non-zero vectors with odd subscripts are used for synthesis, while in even-numbered sectors, only three non-zero vectors with even subscripts are used for synthesis. The actuation durations of three non-zero vectors in each switching period in each sector are given. Simulation and experimental results show that, compared with the conventional SVPWM, the CMV magnitude of CMRSVPWM is reduced by 66.67% and the CMV frequency of CMRSVPWM is reduced from the original switching frequency to the triple fundamental frequency. At the same time, the current, torque and speed of the motor are still good.

scholarly journals Low frequency operation and micro-controller implementation for multilevel quasi Z source inverter in photovoltaic application

2021 ◽  
Author(s):  
Salman Ahmad ◽  
Rahim Uddin ◽  
Zahoor Ahmad Ganie
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Low Frequency ◽  
Control Signal ◽  
Switching Frequency ◽  
Effective Implementation ◽  
Photovoltaic Application ◽  
Detailed Modelling ◽  
Component Design ◽  
Discontinuous Mode

A microcontroller based pulse width modulation implementation for multilevel quasi Z source inverter is proposed in this paper. The component design of quasi z source inverter (qZSI) is first considered with continuous and discontinuous mode of operations. The low switching frequency operation of multilevel quasi Z source inverter is proposed in this paper. The detailed modelling for qZSI is then established for effective implementation of PIC microcontroller (PIC 16F877A) for generating the switching signals. A prototype of five level quasi z-source inverter have been developed and the control signal to the gate drivers have been applied by properly adjusting the shoot through and non shoot through switching states. The hardware result shows the effective implementation of the proposed scheme.

scholarly journals Active EMI Reduction Using Chaotic Modulation in a Buck Converter with Relaxed Output LC Filter

Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 254 ◽  
Author(s):  
Van Nguyen ◽  
Hai Huynh ◽  
SoYoung Kim ◽  
Hanjung Song
Keyword(s):  
Electromagnetic Interference ◽  
Power Efficiency ◽  
Pulse Width Modulation ◽  
Buck Converter ◽  
Oxide Semiconductor ◽  
Switching Frequency ◽  
Cmos Process ◽  
Reference Case ◽  
Ramp Generator ◽  
Chaotic Mode

DC-DC buck converters are widely used in portable applications because of their high power efficiency. However, their inherent fast switching releases electromagnetic emissions, making them prominent sources of electromagnetic interference (EMI). This paper proposes a voltage-controlled buck converter that reduces EMI by using a chaotic pulse-width modulation (PWM) technique based on a chaotic triangular ramp generator. The chaotic triangular ramp generator is constructed from a simple on-chip chaotic circuit linked with a symmetrically triangular ramp circuit. The proposed converter can thus operate in the chaotic mode reducing the EMI without requiring any EMI filters. Additionally, using the triangular ramp signal can relax the requirement for a large LC output filter in chaotic mode. The effectiveness of the proposed scheme was experimentally verified with a chaotic triangular ramp generator embedded in a voltage-mode controller buck converter using a 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) process. The measurement results from a prototype showed that the EMI improvement from the proposed scheme is approximately 14.53 dB at the fundamental switching frequency with respect to the standard fixed-frequency PWM reference case.

scholarly journals Variable-Frequency Pulse Width Modulation Circuits for Resonant Wireless Power Transfer

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3656
Author(s):  
Li-Chuan Tang ◽  
Shyr-Long Jeng ◽  
Edward-Yi Chang ◽  
Wei-Hua Chieng
Keyword(s):  
Duty Cycle ◽  
High Frequency ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Wireless Power Transfer ◽  
Switching Frequency ◽  
Variable Frequency ◽  
Power Transfer ◽  
Wireless Power ◽  
Frequency Pulse

In this paper, we develop a variable-frequency pulse width modulation (VFPWM) circuit for input control of 6.78-MHz resonant wireless power transfer (WPT) systems. The zero-voltage switching control relies on the adjustments of both duty cycle and switching frequency for the class-E amplifier used in the WPT as the power transmission unit. High-frequency pulse wave modulation integrated circuits exist, but some have insufficiently high frequency or unfavorable resolution for duty cycle tuning. The novelty of this work is the VFPWM circuit design that we put together. A voltage-controlled oscillator (VCO) of radio frequency and capacitor-coupled difference amplifiers are used to simultaneously perform the frequency and duty cycle tuning required in resonant WPT applications. Different circuit topologies of VFPWM are compared analytically and numerically. The most favorable circuit topology, enabling independent control of the frequency and duty cycle, is employed in experiments. The experimental results demonstrate the validity of the novel VFPWM, which is capable of operating at 6.78 MHz and has a duty ratio adjustable from 20% to 45% of the range applicable in the resonant WPT applications.

scholarly journals Optimal Modulation Techniques of a DAB Based Isolated Bidirectional Single-stage Single-phase AC-DC Converter

2021 ◽  
Author(s):  
Dibakar Das ◽  
Kaushik Basu ◽  
Sayan Paul
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Degrees Of Freedom ◽  
Single Phase ◽  
Single Stage ◽  
Switching Frequency ◽  
Switching Loss ◽  
Two Stage ◽  
Wide Range ◽  
Bidirectional Power Flow

A bidirectional single-phase AC to DC converter with high-frequency isolation finds a wide range of applications, including charging electric vehicles in the vehicle to grid applications. A conventional two-stage solution, where an AC-DC front-end rectifier is connected to an isolated DC-DC converter, suffers from poor efficiency due to hard switching of the AC-DC stage and poor reliability due to the existence of an electrolytic capacitance at the interstage DC link. A Dual Active Bridge (DAB) based single-stage AC-DC converter with a potential of bidirectional power flow can overcome the problems of a two stage solution. A rich literature exists in search for finding an efficient modulation strategy for this converter. This paper presents two constant switching frequency modulation strategies that support bidirectional power flow at any power factor utilizing all three degrees of freedom in modulation, also known as triple phase-shift modulation (TPS). One of the strategies minimizes RMS high-frequency transformer current over the line cycle, and the other one optimizes peak current. Hence, the conduction loss and the component stress over the entire line cycle are minimized. ZVS conditions are met for all high-frequency switching devices for the whole operating region, while the AC side converter is line frequency switched, incurring negligible switching loss. AC line current waveforms are of high quality and free from low-frequency harmonics. UPF operation is of importance for single-phase power conversion. All possible modes that the converter will experience over a line cycle for UPF operation are elaborated through detailed analysis. The proposed strategies are validated through experiment and simulation with 230 V, 50 Hz AC grid, 400 V DC, UPF, and output power of 1.2 kW.

scholarly journals 4-level capacitor-clamped boost converter with hard-switching and soft-switching implementations

2019 ◽  
Vol 10 (1) ◽  
pp. 288
Author(s):  
A.N. Kasiran ◽  
Asmarashid Ponniran ◽  
A.A. Bakar ◽  
M.H. Yatim
Keyword(s):  
Pulse Width Modulation ◽  
Boost Converter ◽  
Soft Switching ◽  
Switching Frequency ◽  
Switching Loss ◽  
Snubber Circuit ◽  
High Switching Frequency ◽  
Parameters Analysis ◽  
Very High ◽  
Current Ripple

This paper presents parameters analysis of 4-level capacitor-clamped boost converter with hard-switching and soft-switching implementation. Principally, by considering the selected circuit structure of the 4-level capacitor-clamped boost converter and appropriate pulse width modulation (PWM) switching strategy, the overall converter volume able to be reduced. Specifically, phase-shifted of 120° of each switching signal is applied in the 4-level capacitor-clamped boost converter in order to increase the inductor current ripple frequency, thus the charging and discharging times of the inductor is reduced. Besides, volume of converters is greatly reduced if very high switching frequency is considered. However, it causes increasing of semiconductor losses and consequently the converter efficiency is affected. The results show that the efficiency of 2-level conventional boost converter and 4-level capacitor-clamped boost converter are 98.59% and 97.67%, respectively in hard-switching technique, and 99.31% and 98.15%, respectively in soft-switching technique. Therefore, by applying soft-switching technique, switching loss of the semiconductor devices is greatly minimized although high switching frequency is applied. In this study, passive lossless snubber circuit is selected for the soft-switching implementation in the 4-level capacitor-clamped boost converter. Based on the simulation results, the switching loss is approximately eliminated by applying soft-switching technique compared to the hard-switching technique implementation.

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