Optimal low switching frequency pulse width modulation of current-fed five-level inverter for solar integration

Author(s):  
Gnana Sambandam K ◽  
Akshay K. Rathore ◽  
Amarendra Edpuganti ◽  
Dipti Srinivasan
Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3656
Author(s):  
Li-Chuan Tang ◽  
Shyr-Long Jeng ◽  
Edward-Yi Chang ◽  
Wei-Hua Chieng

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.


2017 ◽  
Vol 32 (11) ◽  
pp. 8593-8605 ◽  
Author(s):  
Hussain A. Attia ◽  
Tan Kheng Suan Freddy ◽  
Hang Seng Che ◽  
Wooi Ping Hew ◽  
Ahmad H. El Khateb

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1998
Author(s):  
Shunbin Wu ◽  
Xinhua Guo ◽  
Rongkun Wang ◽  
Yulong Liu ◽  
Liaoyuan Lin ◽  
...  

The four-switch three-phase inverters have become an effective approach for fault-tolerant reconstruction and operation of the six-switch three-phase topology. However, the conventional control strategy for four-switch three-phase inverters can result in a large number of current harmonic components, high electromagnetic acoustic noise, and electromagnetic interference (EMI). Therefore, this paper proposes a random switching frequency pulse width modulation method under the centrosymmetry period with a two-state Markov chain based on four-switch three-phase inverters (RSFPWM-CPTMC). In this method, random numbers are optimized and evenly distributed on both sides of the center frequency within a specific frequency bandwidth range, which significantly reduces the current harmonics and EMI at the switching frequency and frequency multiplication. The spectral characteristics generated by the random switching frequency under the centrosymmetry period with the two-state Markov chain are evaluated and compared to that provided by the traditional fixed switching frequency pulse width modulation (FSFPWM). Simulations and experiments are carried out to illustrate the superiority of the proposal.


2014 ◽  
Vol 573 ◽  
pp. 143-149
Author(s):  
N. Ismayil Kani ◽  
B.V. Manikandan ◽  
Prabakar Perciyal

—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


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 853 ◽  
Author(s):  
Abdul Yasin ◽  
Muhammad Ashraf ◽  
Aamer Bhatti

The key issue in the implementation of the Sliding Mode Control (SMC) in analogue circuits and power electronic converters is its variable switching frequency. The drifting frequency causes electromagnetic compatibility issues and also adversely affect the efficiency of the converter, because the proper size of the inductor and the capacitor depends upon the switching frequency. Pulse Width Modulation based SMC (PWM-SMC) offers the solution, however, it uses either boundary layer approach or employs pulse width modulation of the ideal equivalent control signal. The first technique compromises the performance within the boundary layer, while the latter may not possess properties like robustness and order reduction due to the absence of the discontinuous function. In this research, a novel approach to fix the switching frequency in SMC is proposed, that employs a low pass filter to extract the equivalent control from the discontinuous function, such that the performance and robustness remains intact. To benchmark the experimental observations, a comparison with existing double integral type PWM-SMC is also presented. The results confirm that an improvement of 20% in the rise time and 25.3% in the settling time is obtained. The voltage sag during step change in load is reduced to 42.86%, indicating the increase in the robustness. The experiments prove the hypothesis that a discontinuous function based fixed frequency SMC performs better in terms of disturbances rejection as compared to its counterpart based solely on ideal equivalent control.


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