High frequency LLC DC-transformer based on GaN devices and the dead time optimization

2014 ◽  
Author(s):  
Ren Ren ◽  
Shuo Liu ◽  
Jinlong Wang ◽  
Fanghua Zhang
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Time Optimization ◽  
The Dead ◽  
Dc Transformer

Automatic dead time optimization in a high frequency DC-DC buck converter in 65 nm CMOS

2011 ◽  
Author(s):  
Gerhard Maderbacher ◽  
Thomas Jackum ◽  
Wolfgang Pribyl ◽  
Michael Wassermann ◽  
Andreas Petschar ◽  
...  
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Buck Converter ◽  
Time Optimization

scholarly journals Analysis and Elimination of Dead-Time Effect in Wireless Power Transfer System

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1577 ◽  
Author(s):  
Xin Liu ◽  
Tianfeng Wang ◽  
Nan Jin ◽  
Salman Habib ◽  
Muhammad Ali ◽  
...  
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Short Circuit ◽  
Wireless Power Transfer ◽  
Time Effect ◽  
Voltage Source ◽  
Power Transfer ◽  
Wireless Power ◽  
Voltage Distortion ◽  
The Dead

Dead time between the complementary driving signals is needed to avoid short circuit in voltage source inverters (VSIs), however, this raises issues such as voltage distortion and harmonic generation. In wireless power transfer (WPT) systems, the ratio of dead time versus operating period becomes more problematic due to the high frequency, where the dead time can cause serious concerns regarding the phase errors and control performance deterioration. Therefore, this paper presents a comprehensive analysis of the dead-time effect for WPT systems based on a series–series (SS) topology. Firstly, it is found that voltage distortion appears in two regions in comparison with the three in one active bridge WPT system, and seven regions, as compared to the eight in dual active bridge (DAB) WPT system. Afterwards, a novel pulse width modulation (PWM) method is proposed, where the driving signals of the same phase leg are no longer complementary to each other. By employing the proposed method, the dead-time effect can be addressed up to a certain extent, and the desired voltage can be obtained in all the regions. In addition, the proposed method is not influenced by the system parameters, and can be easily applied to other high-frequency resonant converters. Simulated and experimental results are added to verify the feasibility and efficacy of the proposed control scheme.

scholarly journals Delay compensation based controller for rotary electrohydraulic servo system

2021 ◽  
Author(s):  
Zakarya Omar ◽  
Xingsong Wang ◽  
Khalid Hussain ◽  
Mingxing Yang
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Sliding Mode ◽  
Servo System ◽  
Smith Predictor ◽  
Delay Compensation ◽  
Mechanical Parts ◽  
System Output ◽  
Electrohydraulic Servo System ◽  
The Stability

AbstractThe typical power-assisted hip exoskeleton utilizes rotary electrohydraulic actuator to carry out strength augmentation required by many tasks such as running, lifting loads and climbing up. Nevertheless, it is difficult to precisely control it due to the inherent nonlinearity and the large dead time occurring in the output. The presence of large dead time fires undesired fluctuation in the system output. Furthermore, the risk of damaging the mechanical parts of the actuator increases as these high-frequency underdamped oscillations surpass the natural frequency of the system. In addition, system closed-loop performance is degraded and the stability of the system is unenviably affected. In this work, a Sliding Mode Controller enhanced by a Smith predictor (SMC-SP) scheme that counts for the output delay and the inherent parameter nonlinearities is presented. SMC is utilized for its robustness against the uncertainty and nonlinearity of the servo system parameters whereas the Smith predictor alleviates the dead time of the system’s states. Experimental results show smoother response of the proposed scheme regardless of the amount of the existing dead time. The response trajectories of the proposed SMC-SP versus other control methods were compared for a different predefined dead time.

scholarly journals Dead-Time Correction Applied for Extended Flux-Based Sensorless Control of Assisted PMSMs in Electric Vehicles

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 220
Author(s):  
Cheng Lin ◽  
Jilei Xing ◽  
Xingming Zhuang
Keyword(s):  
Control System ◽  
Electric Vehicles ◽  
Dead Time ◽  
Sensorless Control ◽  
Correction Method ◽  
Time Effect ◽  
Dead Time Correction ◽  
Speed Range ◽  
Time Correction ◽  
The Dead

Sensorless control technology of PMSMs is of great importance for safety and reliability in electric vehicles. Among all existing methods, only the extended flux-based method has great performance over all speed range. However, the accuracy and reliability of the extended flux rotor position observer are greatly affected by the dead-time effect. In this paper, the extended flux-based observer is adopted to develop a sensorless control system. The influence of dead-time effect on the observer is analyzed and a dead-time correction method is specially designed to guarantee the reliability of the whole control system. A comparison of estimation precision among the extended flux-based method, the electromotive force (EMF)-based method and the high frequency signal injection method is given by simulations. The performance of the proposed sensorless control system is verified by experiments. The experimental results show that the proposed extended flux-based sensorless control system with dead-time correction has satisfactory performance over full speed range in both loaded and non-loaded situations. The estimation error of rotor speed is within 4% in all working conditions. The dead-time correction method improves the reliability of the control system effectively.

scholarly journals Adopting pade approximation for first order plus dead time models for blending process

2018 ◽  
Vol 7 (4) ◽  
pp. 2800
Author(s):  
Avani Kirit Mehta ◽  
R. Swarnalatha
Keyword(s):  
Dead Time ◽  
Padé Approximation ◽  
Continuous Process ◽  
Process Variable ◽  
Pade Approximation ◽  
Process Systems ◽  
First Order ◽  
Blending Process ◽  
The Dead ◽  
Control Feedback

Dead-time is common to real time processes and occurs when the process variable doesn’t acknowledge to any changes in the set point. Existence of dead time in the systems poses a challenge to control and stabilize, especially in a control feedback loop. Padé approximation provides a determinate approximation of the dead time in the continuous process systems, which can be utilized in the further simulations of equivalent First Order plus Dead Time Models. However, the standard Padé approximation with the same numerator- denominator derivative power, exhibits a jolt at time t=0. This gives an inaccurate approximation of the dead time. To avoid this phenomenon, increasing orders of Padé approximation is applied. In the following manuscript, equivalent First Order plus Dead-Time models of two blending systems of orders four and seven are analysed for the same. As the orders of the Padé approximation increases, the accuracy of the response also increases. The oscillations are increased on a much smaller scale rather than having one big dip in the negative region (as observed in the first few orders of Padé approximation), and the approximation tries to synchronize with the desired response curve in the positive region. All the simulations are done in MATLAB.  

High Frequency ZVS GaN-Inverter with Adaptive Dead Time

2021 ◽  
Author(s):  
Benedikt Kohlhepp ◽  
Thomas Foerster ◽  
Thomas Duerbaum
Keyword(s):  
High Frequency ◽  
Dead Time
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