A small-signal harmonic model of a closed-loop power converter

2012 ◽  
Author(s):  
K. L. Lian
Keyword(s):  
Closed Loop ◽  
Power Converter ◽  
Small Signal ◽  
Harmonic Model

Logic-Based Switching Adaptive Control of DC-DC Buck Converter

2012 ◽  
Vol 229-231 ◽  
pp. 2209-2212
Author(s):  
Bao Bin Liu ◽  
Wei Zhou
Keyword(s):  
Adaptive Control ◽  
Closed Loop ◽  
Buck Converter ◽  
Uncertain Parameters ◽  
Small Signal ◽  
Closed Loop System ◽  
Unknown Parameters ◽  
Signal Model ◽  
Small Signal Model ◽  
Control Scheme

Logic-based switching adaptive control scheme is proposed for the model of DC-DC buck converter in presence of uncertain parameters and power supply disturbance. All uncertain parameters and the disturbance are estimated together through constructing Lyapunov function. And a switching mechanism is used to ensure global asymptotic stability of the closed-loop system. The results of simulation show that even if there are multiple unknown parameters in the small-signal model, the control system of DC-DC buck converter can estimate unknown parameters quickly and accurately.

scholarly journals Small Signal Modeling and Analysis of a Dual Input Interleaved DC-DC Converter

2020 ◽  
Vol 8 (6) ◽  
pp. 5402-5411
Keyword(s):  
Performance Analysis ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Energy System ◽  
Vital Role ◽  
Performance Comparison ◽  
Small Signal ◽  
Solar Pv ◽  
Modeling And Analysis ◽  
Hybrid Energy

The idea of DC-DC converter with multi-input is yet to attain a vital role in the field of 'hybrid energy system (HES)' integration and electric vehicle applications. So, the analysis of the dynamic behavior of the multi input converters is crucial in designing a proper controller to achieve a stable performance. This paper reports a 'small signal model (SSM)' and the performance analysis of a 'dual-input DC-DC converter (DIC)'. The parasitic resistances of capacitor and inductor are considered in the modelling. The significant transfer function (TF)s are derived with the help of the SSM, and the Bode plots for the TFs have been obtained. The performance analysis shows that the derived TFs allow better closed loop performance of the system. The simulation of the DIC converter in MATLAB/ Simulink® has been carried out and the simulation waveforms are presented. A hardware setup of the DIC converter is fabricated and experimented in the laboratory. The dynamic performance of the DIC is analyzed under the variations in the source and load conditions. The presented converter with a closed loop controller can be used in the applications to formulate a HES with solar-PV, battery, fuel cell, etc. Also the performance comparison of the DIC converter has been performed with other reported converters which shows that the DIC converter has higher efficiency and several other potential merits.

scholarly journals Sufficient Condition-Based Stability Analysis of a Power Converter Applied Switching Transient Waveform Modification Using Kharitonov’s Theorem

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 245
Author(s):  
Tongkai Cui ◽  
Qishuang Ma ◽  
Ping Xu
Keyword(s):  
Stability Analysis ◽  
Closed Loop ◽  
Power Converters ◽  
System Stability ◽  
Sufficient Condition ◽  
Small Signal ◽  
Design Guideline ◽  
Saturation Region ◽  
Kharitonov’S Theorem ◽  
Kharitonov's Theorem

The rapid switching action of power metal-oxide-semiconductor field-effect transistor (MOSFET) causes high-level electromagnetic interference (EMI) in power converters. The switching transient waveform modification method realized by closed-loop gate drive has been recognized as an effective high-frequency EMI reduction approach. However, feedback control of power MOSFET in the saturation region would introduce stability problems. This paper presents a sufficient condition-based stability analysis of all the operating points during turn-off using Kharitonov’s theorem. Firstly, a small-signal MOSFET model during turn-off was used to derive the closed-loop system transfer function. The nonlinear capacitances and the rest constant parameters of the small-signal model were determined based on the device characteristics and the expected outcome of the drain-source voltage. Then we split the turn-off switching transient into several subintervals, during which the system characteristic equation became an interval polynomial due to the nonlinear capacitances. Finally, Kharitonov’s theorem was applied in each subinterval to evaluate the stability, thereby achieving the overall system stability analysis during turn-off. Experiments were conducted to investigate the system’s stability and the results confirmed the validity of the proposed analysis. This work presents an implementable design guideline for the applied switching transient waveform modification of power converters via closed-loop gate drive.

scholarly journals Review and Selection Strategy for High-Accuracy Modeling of PWM Converters in DCM

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Yu-Jun Mao ◽  
Chi-Seng Lam ◽  
Sai-Weng Sin ◽  
Man-Chung Wong ◽  
Rui Paulo Martins
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
High Accuracy ◽  
Operating Conditions ◽  
Selection Strategy ◽  
Small Signal ◽  
Pwm Converters ◽  
Modeling Methods ◽  
The Past ◽  
Conduction Mode

Among various modeling methods for DC-DC converters introduced in the past two decades, the state-space averaging (SSA) and the circuit averaging (CA) are the most general and popular exhibiting high accuracy. However, their deduction approaches are not entirely equivalent since they incorporate different averaging processes, thus yielding different small signal transfer functions even under identical operating conditions. Some research studies claimed that the improved SSA can obtain the highest accuracy among all the modeling methods, but this paper discovers and clearly verifies that this is not the case. In this paper, we first review and study these two modeling methods for various DC-DC converters operating in the discontinuous conduction mode (DCM). We also streamline the general model-deriving processes for DC-DC converters, and test and compare the accuracy of these two methods under various conditions. Finally, we provide a selection strategy for a high-accuracy modeling method for different DC-DC converters operating in DCM and verified by simulations, which revealed necessary and beneficial for designing a more accurate DCM closed-loop controller for DC-DC converters, thus achieving better stability and transient response.

Development of Robust Excitation Controller for Synchronous Generator

2014 ◽  
Vol 573 ◽  
pp. 328-333
Author(s):  
R. Ramya ◽  
K. Selvi ◽  
M. Tamilvanan
Keyword(s):  
Output Voltage ◽  
Closed Loop ◽  
Synchronous Generator ◽  
Local Mode ◽  
Small Signal ◽  
Closed Loop System ◽  
Robust Controller ◽  
Sensitivity Approach ◽  
Single Machine Infinite Bus ◽  
The Stability

This paper deals with the design and evaluation of robust excitation controller for a single-machine infinite-bus power system. The design of the regulator guarantees the stability of the closed loop system and ensures the output voltage is maintained within an acceptable threshold. In addition, it damps out local mode oscillations for small signal disturbances. The designed robust controller is also analyzed under change in step input and disturbance, which limits the heavy oscillations on the speed ω and voltage. Glover-McFarlane loop shaping algorithm is applied in designing the robust excitation controller. Two different techniques such as Optimal control and mixed sensitivity approach is used in this paper. The performance of the AVR was analyzed and compared with IEEE type2 Exciter.

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