scholarly journals A Detection Circuit for Improving the Unloading Transient Performance of the COT Controller

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2333
Author(s):  
Xi Zhang ◽  
Tianshi Wang ◽  
Bocheng Bao
Keyword(s):  
Transient Response ◽  
Output Voltage ◽  
Buck Converter ◽  
Control Technique ◽  
Time Interval ◽  
Transient Performance ◽  
Load Step ◽  
Light Load ◽  
Detection Circuit ◽  
Step Down

Fast load transient response and high light-load efficiency are two key features of the constant on-time (COT) control technique that has been widely used in numerous applications, such as for voltage regulators and point-of-load converters. However, when load step-down occurs during an on-time interval, the COT controller cannot respond until the COT interval expires. This delay causes an additional output voltage overshoot, resulting in unloading transient performance limitation. To eliminate the delay and improve the unloading transient response of the COT controller, a load step-down detection circuit is proposed based on capacitor current COT (CC-COT) control. In the detection circuit, the load step-down is monitored by comparing the measured capacitor current with the preset threshold voltage. Once the load step-down is monitored, the on-time is promptly truncated and the switch is turned off. With the proposed detection circuit, the CC-COT-controlled buck converter can monitor the load step-down without any delay and obtain less output voltage overshoot when the load step-down occurs during the on-time interval. PSIM circuit simulations are employed to demonstrate the feasibility of the detection circuit.

scholarly journals Dynamic Modeling and Closed-Loop Control of a Tapped Inductor Buck Converter

2021 ◽  
Author(s):  
Siripan Trakuldit ◽  
Chanin Bunlaksananusorn
Keyword(s):  
Dynamic Modeling ◽  
Transient Response ◽  
Output Voltage ◽  
Closed Loop ◽  
High Efficiency ◽  
Buck Converter ◽  
Closed Loop Control ◽  
Voltage Step ◽  
Loop Control ◽  
Step Down

Modern smart electronic and information technology (IT) devices require a low DC voltage for operation. The low supply voltage is typically provided by a dedicated DC−DC converter by stepping down the system’s bus voltage (e.g., 12 V). It is essential that the converter possesses a large voltage step-down gain and, at the same time, operates at high efficiency. A tapped inductor buck converter (TIBC) is a topology that has a potential to meet these requirements. It has a simple circuit structure and high efficiency similar to a buck converter, but can give a larger voltage step-down gain. This paper presents a dynamic modeling and closed-loop control of a TIBC. The state space averaging (SSA) method is adopted for the dynamic modeling to derive small-signal transfer functions of the converter. Based on the duty-cycle-to-output voltage transfer function, a closed-loop control is designed to keep the converter’s output voltage constant. To verify the design, a prototype TIBC with closed-loop control is implemented. Experimental results show that the prototype converter has good output voltage regulation and fast transient response when subject to a step load. The effect of the crossover frequency and phase margin on the converter’s transient response is also illustrated.

Improved Load Sharing Control Techniques for Inverters used in a Microgrid

2009 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Yao ◽  
Zhaoming Qian
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Single Phase ◽  
Load Sharing ◽  
Power Sharing ◽  
Experimental Results ◽  
Control Technique ◽  
Transient Performance ◽  
Control Techniques ◽  
Control Scheme

In this paper, an improved load sharing control scheme is presented, which is able to improve the transient response and power sharing accuracy of parallel-connected inverters used in microgrid. It also shows how the improved droop method can be easily adapted to account for the operation of parallel-connected inverters, providing good performance under the variation and disturbance of loads, as well as achieving good steady-state objectives and transient performance. Two DSP-based single-phase Microgrid inverters are designed and implemented. Simulation and experimental results are all reported, confirming the validity of the proposed control technique.

scholarly journals Novel Step-Down DC–DC Converters Based on the Inductor–Diode and Inductor–Capacitor–Diode Structures in a Two-Stage Buck Converter

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1131 ◽  
Author(s):  
Mauricio Dalla Vecchia ◽  
Giel Van den Broeck ◽  
Simon Ravyts ◽  
Johan Driesen
Keyword(s):  
Output Voltage ◽  
Buck Converter ◽  
Switching Frequency ◽  
Two Stage ◽  
Voltage Level ◽  
Multiple Strategies ◽  
Power Electronics Converters ◽  
Load Demand ◽  
Duty Cycles ◽  
Step Down

This paper explores and presents the application of the Inductor–Diode and Inductor-Capacitor-Diode structures in a DC–DC step-down configuration for systems that require voltage adjustments. DC micro/picogrids are becoming more popular nowadays and the study of power electronics converters to supply the load demand in different voltage levels is required. Multiple strategies to step-down voltages are proposed based on different approaches, e.g., high-frequency transformer and voltage multiplier/divider cells. The key question that motivates the research is the investigation of the aforementioned Inductor–Diode and Inductor–Capacitor–Diode, current multiplier/divider cells, in a step-down application. The two-stage buck converter is used as a study case to achieve the output voltage required. To extend the intermediate voltage level flexibility in the two-stage buck converter, a second switch was implemented replacing a diode, which gives an extra degree-of-freedom for the topology. Based on this modification, three regions of operation are theoretically defined, depending on the operational duty cycles δ2 and δ1 of switches S2 and S1. The intermediate and output voltage levels are defined based on the choice of the region of operation and are mapped herein, summarizing the possible voltage levels achieved by each configuration. The paper presents the theoretical analysis, simulation, implementation and experimental validation of a converter with the following specifications; 48 V/12 V input-to-output voltage, different intermediate voltage levels, 100 W power rating, and switching frequency of 300 kHz. Comparisons between mathematical, simulation, and experimental results are made with the objective of validating the statements herein introduced.

A HIGH EFFICIENCY ADAPTIVE CURRENT MODE STEP-UP/STEP-DOWN DC–DC CONVERTER WITH FOUR MODES FOR SMOOTH TRANSITION

2014 ◽  
Vol 23 (07) ◽  
pp. 1450097 ◽  
Author(s):  
YANZHAO MA ◽  
SHAOXI WANG ◽  
SHENGBING ZHANG ◽  
XIAOYA FAN
Keyword(s):  
Transient Response ◽  
Output Voltage ◽  
High Efficiency ◽  
Current Mode ◽  
Smooth Transition ◽  
Maximum Efficiency ◽  
Cmos Process ◽  
Voltage Ripple ◽  
Transition Modes ◽  
Step Down

This paper presents a current mode step-up/step-down DC–DC converter with high efficiency, small output voltage ripple, and fast transient response. The control scheme adaptively configures the converter into the proper operation mode. The efficiency is improved by reducing the switching loss, wherein the converter operates like a buck or boost converter, and conduction loss, wherein the average inductor current is reduced in transition modes. The output voltage ripple is significantly reduced by incorporating two constant time transition modes. A fast line transient response is achieved with small overshoot and undershoot voltage. An adaptive substrate selector (ASS) is introduced to dynamically switch the substrate of PMOS power transistors to the highest on-chip voltage. A lossless self-biased current sensor with high-speed and high-accuracy is also achieved. The proposed converter was designed with a standard 0.5 μm CMOS process, and can regulate an output voltage within the input voltage ranged from 2.5 V to 5.5 V. The maximum load current is 600 mA, and the maximum efficiency is 94%. The output voltage ripple is less than 15 mV in all operation modes.

scholarly journals Adaptive On-Time Control Buck Converter with a Novel Virtual Inductor Current Circuit

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2143 ◽  
Author(s):  
Hsiao-Hsing Chou ◽  
Hsin-Liang Chen ◽  
Yang-Hsin Fan ◽  
San-Fu Wang
Keyword(s):  
Control Mechanism ◽  
Circuit Complexity ◽  
Design Procedure ◽  
Input Voltage ◽  
Cmos Technology ◽  
Buck Converter ◽  
Load Step ◽  
Time Control ◽  
Simulation Results ◽  
Step Down

This study presents a new virtual inductor current circuit to reduce circuit complexity, which is not necessary to sense inductance current directly. The buck converter was designed to produce an output voltage of 1.0–2.5 V for a 3.0–3.6 V input voltage. The load current range was from 100 mA to 500 mA. It was simulated and verified by SIMPLIS and MathCAD. The simulation results of this buck converter show that the voltage error is within 1%, and the recovery time is smaller than 2 ms for step-up and step-down load transients. Additionally, it achieves less than 26 mV overshoot at full-load step transient response. The circuit topology would be able to fabricate using TSMC 0.35 mm 2P4M CMOS technology. The control mechanism, implementation, and design procedure are presented in this paper.

scholarly journals Stability Analysis in Positive Output and Negative Output DC to DC Converters Used in Renewable Energy Applications

2019 ◽  
Author(s):  
Maheswari Ellappan ◽  
Kavitha Anbukumar
Keyword(s):  
Renewable Energy ◽  
Stability Analysis ◽  
Output Voltage ◽  
Monodromy Matrix ◽  
Period Doubling ◽  
Current Mode ◽  
Power Converter ◽  
Control Technique ◽  
Step Down ◽  
The Stability

The renewable energy source plays a major role in the grid side power production. The stability analysis is very essential in the renewable energy converters. In this paper the bifurcation is analyzed in ZETA converter and Continuous input and output(CIO) power Buck Boost converter. The ZETA converter gives positive step down and step up output voltage and the CIO power converter gives the negative step up and step down output voltage. These converters are used in the DC micro grid with renewable energy as the source. The current mode control technique is applied to analyze the bifurcation behavior and the reference current is taken as the bifurcation parameter. When the reference current is varied, both the converters loses its stability and it enters into chaotic region through period doubling bifurcation. The simulation results are presented to study the performance behavior of both the converters. The stability region of both the converters are determined by deriving the Monodromy matrix approach.

Fuzzy Gain Scheduling of PI Plus Derivative Controller to Improve the Transient Response of Boost DC/DC Converter

2015 ◽  
Vol 781 ◽  
pp. 414-417
Author(s):  
Yutthana Kanthaphayao ◽  
Chalermpol Reaungepattanawiwat
Keyword(s):  
Control System ◽  
Steady State ◽  
Transient Response ◽  
Output Voltage ◽  
Input Voltage ◽  
Gain Scheduling ◽  
Voltage Regulation ◽  
Control Technique ◽  
Transient Responses ◽  
System Operation

This paper illustrates a fuzzy gain scheduling of PI plus derivative controller. The proposed control technique improves the transient response of a DC/DC converter. The proposed control system is easy to implement based on an STM32F4 microcontroller. The performance evaluation was done by an experiment through a boost DC/DC converter, with a 24W load, a 12V input voltage, and a 24V output voltage, respectively. The system operation achieves tight output voltage regulation, both for the steady-state and transient responses.

State Feedback Controller Using Pole Placement Method for Linear Buck Converter to Improve Overshoot and Settling Time

2015 ◽  
Vol 793 ◽  
pp. 211-215
Author(s):  
Mazwin Mazlan ◽  
Noor Haqkimi ◽  
Chanuri Charin ◽  
Nur Fairuz ◽  
Nurul Izni ◽  
...  
Keyword(s):  
Output Voltage ◽  
State Feedback ◽  
Input Voltage ◽  
Buck Converter ◽  
Pole Placement ◽  
Electronic Circuits ◽  
Solution Approach ◽  
Placement Method ◽  
Lqr Controller ◽  
Step Down

Switched mode DC-DC converters are electronic circuits which convert a voltage from one level to a higher or lower level voltage. This paper presents a new solution approach to controller and observer controller of DC-DC Buck converter. The designs in this paper of DC-DC Buck converter is input voltage 20V step down to 12V output voltage. For control the system simulation investigation into development of controller and observer controller using MATLAB Simulink® software. The simulation develops of the controller and observer controller with mathematical model of DC-DC Buck converter. This paper also providing LQR controller to compare the performance of the system. Finally, the performance output voltage of DC-DC Buck converter is analyzed in terms of time response, overshoot and steady state error.

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