Fraction Phase Lead Repetitive Control and its Application in Inverter

2015 ◽  
Author(s):  
Jianhong Wang ◽  
Yongqiang Ye ◽  
YangQuan Chen
Keyword(s):  
High Power ◽  
Stability Region ◽  
Sampling Rate ◽  
Repetitive Control ◽  
Switching Frequency ◽  
Harmonic Suppression ◽  
Tracking Accuracy ◽  
Power Devices ◽  
Phase Lead ◽  
The Stability

In order to reduce turn-off losses, the switching frequency of power devices, which is sampling rate, is usually chosen to be low in high power inverter application. Limited by the digital sampling, phase lead step should be integer, in which case the repetitive control tends to be unstable under low sampling application. Thus fractional phase lead repetitive control is proposed. This method enables the phase lead step can be fractional, thus enlarges the stability region and improves the tracking accuracy as well. The detailed parameters design is given. At last, simulations of inverter using fractional phase lead repetitive control are presented. The results verify that fractional phase lead repetitive control favors better stability and harmonic suppression.

Nonlinear Analysis for a Two-Phase Natural Circulation Loop Under Low-Pressure

2010 ◽  
Author(s):  
Arrdaneh Kazem ◽  
Zaferanlouei Salman ◽  
Mohsen Farahi ◽  
Asad Allah Ahmadi
Keyword(s):  
Low Power ◽  
High Power ◽  
Parametric Study ◽  
Stability Region ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Two Phase ◽  
Natural Circulation Loop ◽  
The Stability ◽  
Power Region

The purpose of this paper is to develop a nonlinear model to investigate the instabilities of a two-phase natural circulation loop under low-pressure condition. Inlet velocity oscillations and the corresponding trajectories are respectively presented in the time evolution planes and phase planes. We obtain a stability map to explore the instability regions of this natural circulation loop. The results show that the considered loop has two unstable regions, instability type-I in the low power region and instability type-II in the high power region. Then the parametric study is carried out to understand the relation between the parameters of system and two types of instability. The parametric study reveals that lengthening the riser has an unstable effect on system stability. Thus, lengthening the riser causes a reduction in the stability region in the both low power and high power levels. Also it can be observed that by increasing the form loss coefficient at the inlet of heated section or in the downcomer section, the stability region expands, however by increasing the form loss coefficient at the outlet of heated section or in the upper horizontal section, the stability region decreases consequently.

THE CONNECTION OF CONVERTERS INSTEAD OF SEMICONDUCTOR POWER DEVICES — A HIGH PERFORMANCE SOLUTION FOR THE MVA RANGE OF POWER COMVERTERS

1995 ◽  
Vol 05 (03) ◽  
pp. 503-521 ◽  
Author(s):  
LOURENCO MATAKAS ◽  
CATALIN BURLACU ◽  
EISUKE MASADA
Keyword(s):  
High Power ◽  
High Performance ◽  
Power Converters ◽  
State Of The Art ◽  
High Reliability ◽  
Motor Drives ◽  
Switching Frequency ◽  
Power Devices ◽  
Parallel Connection ◽  
Severe Limitation

Recently, there is an increased demand for high power, high performance converters for power system applications, motor drives, etc. The low switching frequency of the existing semiconductor power devices poses a severe limitation that can be overcome by the use of interconnected smaller power converters (multiconverter) with appropriate control. This paper gives an overview of the state of the art of multiconverters, followed by a comparison based on analytically calculated values of the spectra, RMS and peak values of their ripple currents, and the peak values of the transformer's flux. Special attention has been given to show that the transformerless parallel connection of converters is feasible and offers features such as simplicity, gracefully degrading operating, high reliability, easy expandability and easy maintenance.

scholarly journals A Novel SHMPWM Technique for Sensorless Control in High-Power PMSM

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yanjun Yu ◽  
Lixiao Gao ◽  
Yue Liu ◽  
Feng Chai ◽  
Shukang Cheng
Keyword(s):  
High Power ◽  
Sensorless Control ◽  
Transcendental Equation ◽  
Switching Frequency ◽  
Band Pass Filter ◽  
Harmonic Suppression ◽  
The Novel ◽  
Pass Filter ◽  
Rotor Position ◽  
Harmonic Signals

In view of the low switching frequency restriction of high-power permanent magnet synchronous motor (PMSM) drive system and longing for sensorless control in hostile conditions, a novel PWM control scheme, born out of selective harmonic mitigation pulse width modulation (SHMPWM) technique, was proposed for sensorless control of high-power PMSM. A new enhanced constraint was placed on the traditional SHMPWM nonlinear transcendental equation to selectively generate constant amount of a certain3k+1order harmonic signals while guaranteed that the undesired harmonic signals can be suppressed. At the same time, the3k+1order harmonic signals were extracted by band-pass filter, which had the constant amplitude and phase angle difference of 120°, equivalent to inject rotating voltage vector in the natural coordinate system of motor, and the rotor position can be estimated using the3k+1order harmonic signals. The nonlinear transcendental equation of the novel modulation technique had been designed, and its numerical method had been analyzed. The rotor position observer had been designed according to the3k+1order harmonic signals. Simulation results verify that the harmonic suppression of the system was implemented, and the sensorless control was efficient by the novel SHMPWM technique.

Study of Flow Instabilities in a Natural Circulation Boiling System

2010 ◽  
Author(s):  
Arrdaneh Kazem ◽  
Ahmadi Asad allah ◽  
Mohsen Farahi ◽  
Zaferanlouei Salman
Keyword(s):  
Low Power ◽  
High Power ◽  
Parametric Study ◽  
Stability Region ◽  
Natural Circulation ◽  
Loss Coefficient ◽  
Circulation Loop ◽  
Natural Circulation Loop ◽  
The Stability ◽  
Power Region

The purpose of this paper is to develop a nonlinear model to investigate the instabilities of a two-phase natural circulation loop. We obtain a stability map to explore the unstable regions of this natural circulation loop. The results show that the considered loop has two unstable regions, instability type-I in the low power region and instability type-II in the high power region. Then the parametric study is carried out to understand the relation between the parameters of system and two types of instability. The parametric study reveals that lengthening the riser has an unstable effect on system stability. Thus, lengthening the riser causes a reduction in the stability region in the both low power and high power levels. Also it can be observed that by increasing the form loss coefficient at the inlet of heated section or in the downcomer section, the stability region expands, however by increasing the form loss coefficient at the outlet of heated section or in the upper horizontal section, the stability region decreases consequently.

The influence of the Stokes and Archimedes forces on the stability of a two-phase flow

2003 ◽  
Vol 3 ◽  
pp. 266-270
Author(s):  
B.H. Khudjuyerov ◽  
I.A. Chuliev
Keyword(s):  
Spectral Method ◽  
Stability Region ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Solid Phase ◽  
Stability Characteristic ◽  
Phase Flow ◽  
Two Phase ◽  
The Stability

The problem of the stability of a two-phase flow is considered. The solution of the stability equations is performed by the spectral method using polynomials of Chebyshev. A decrease in the stability region gas flow with the addition of particles of the solid phase. The analysis influence on the stability characteristic of Stokes and Archimedes forces.

Enlarging the region of stability in robust model predictive controller based on dual-mode control

2021 ◽  
pp. 014233122110123
Author(s):  
Fatemeh Khani ◽  
Mohammad Haeri
Keyword(s):  
Stability Region ◽  
Linear Matrix ◽  
Input State ◽  
Dual Mode ◽  
Model Predictive Controller ◽  
Mode Control ◽  
Robust Model ◽  
Output Constraints ◽  
Predictive Controller ◽  
The Stability

Industrial processes are inherently nonlinear with input, state, and output constraints. A proper control system should handle these challenging control problems over a large operating region. The robust model predictive controller (RMPC) could be an linear matrix inequality (LMI)-based method that estimates stability region of the closed-loop system as an ellipsoid. This presentation, however, restricts confident application of the controller on systems with large operating regions. In this paper, a dual-mode control strategy is employed to enlarge the stability region in first place and then, trajectory reversing method (TRM) is employed to approximate the stability region more accurately. Finally, the effectiveness of the proposed scheme is illustrated on a continuous stirred tank reactor (CSTR) process.

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