Switching DC-DC Power Converters Research Articles

Online die temperature measurement using S-parameters in GaN-based power converters

Die temperature (Tj) measurement of GaN HEMTs is of high interest to enable reducing design margin and the implementation of reliability driven control schemes and protections. On-state resistance (Rds,on) has been identified as a relevant thermo-electric sensitive parameter (TSEP) for Tj measurement requiring no extra temperature sensor. It is commonly measured in time-domain, based on the on-state voltage drop and the load current. In this work, the Tj of a GaN-on-Si power IC in a dc-dc converter is deduced from measurements conducted online, directly in the frequency domain using RF injection and S-parameter measurements. Thereby, the stimulus is injected on top of the processed power to probe either Rds,on, or the resistance of an on-chip Schottky diode used as thermal sensor. Temperature dependent experimental validation up to 150 °C is performed on a switching dc-dc power converter, validating the approach for online temperature measurement using RF injection.

Dynamic Sensorless Control Approach for Markovian Switching Systems Applied to PWM DC-DC Converters with Time-Delay and Partial Input Saturation.

This paper provides a detailed analysis of the output voltage/current tracking control of a PWM DCDC converter that has been modeled as a Markov jump system. In order to achieve that, a dynamic sensorless strategy is proposed to perform active disturbance rejection control. As a convex optimization problem, a novel reformulation of the problem is provided to compute optimal control. Accordingly, necessary less conservative conditions are established via Linear Matrix Inequalities. First, a sensorless active disturbance rejection design is proposed. Then, to carry out the control process, a robust dynamic observer-predictive controller approach is introduced. Meanwhile, the PWM DC-DC switching power converters are examined as discrete-time Markovian switching systems. Considering that the system is subject to modeling uncertainties, time delays, and load variations as external disturbances, and by taking partial input saturation into account, the Lyapunov-Krasovskii function is used to construct the required feasibility frame and less conservative stability conditions. As a result, the proposed design provides an efficient control strategy with disturbance rejection and time-delay compensation capabilities and maintains robust performance with respect to constraints. Finally, a PWM DC-DC power converter simulation study is performed in different scenarios, and the obtained results are illustrated in detail to demonstrate the effectiveness of the proposed approach.

Comparison between boost and positive output super lift Luo converters to improve the performance of photovoltaic system

Employment DC-DC switching power converters in many different areas become is very important. In this paper, three different models of the photovoltaic solar module were proposed in order to designing, implementation, and simulated them in MATLAB/Simulink with the boost converter circuit first and then with the positive output super lift Luo (POSLL) converter circuit again. A comparison was made between the two circuits, as well as a theoretical and simulation values were made and compared between them (in the same standard conditions) for each of these selected models. So as to improving solar system performance and clarify the functions played by POSLL in power electronic circuits.

A Review of High Efficiency Non-Isolated DC-DC Power Converters for Electric Vehicle Charging Application

The electric vehicle (EV) charging systems employ dc-dc power converters as EV chargers. Currently, the expected high penetration of electric vehicle (EV) demands for the integration of the renewable energy sources (RES) into the electric vehicle charging system as a promising solution to cut down the load on the electrical grid. These systems interface with RES by implementing dc-dc power converters. Moreover, with the advent of high-power dc charging, the charging efficiency is largely dependent on the performance of the power converters. Hence, to improve the charging, the soft switching dc-dc converters are implemented to maintain low switching losses and to achieve high-efficiency operation. This paper reviews the non-isolated, soft switching dc-dc power converters for EV charging application. For this purpose, different types of soft switching topologies, namely the snubber, the series resonant, the shunt resonant and the pulse frequency modulated converters are investigated. The advantages and the disadvantages associated with these converters are highlighted. Furthermore, to perform a comparative evaluation, the topologies are simulated in a standard simulation platform. Consequently, the relative standing of the converters depending on several parameters, i.e. the component count, the output voltage and current ripple, the soft switching range, and the power losses are established. Finally, based on these results, the optimum applicability of the converters in the EV charging application is determined.
 GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 6(1), Dec 2019 P 60-74

Selection of Inductor and Snubber Capactor to Optimize the Size and Efficiency of DC-DC Switching Power Converter

This paper presents a selection of inductor and snubber capacitor in non-isolated synchronous DC-DC switching power converter. The circuit is made to operate in Synchronous Discontinuous Conduction Mode (SDCM)/Forced Continuous Conduction Mode (FCCM) of operation for minimum inductor value, to reduce the size, weight and cost of the converter. The turn off loss of the switch induced by SDCM of operation is minimized by connecting snubber capacitor across the transistor switch. Before the switch is turned ON, snubber capacitor requires certain amount of energy must be stored in the inductor to discharge the capacitor energy [1]. The question is how much capacitor and inductor value is required. A series of MATLAB script are executed to find minimum inductor value for FCCM of operation and to select snubber capacitor for maximum efficiency. Complementary gate signals are used to control the ON and OFF of main and auxiliary switch. SDCM of operation due to complementary control gate signal scheme, minimum turn on loss of the transistor switch and low diode reverse recovery loss are achieved. Thus the Zero Voltage Resonant Transition (ZVRT) of transistor switch is realized, both turn on and turn off loss is minimized and also removes the parasitic ringing in inductor current.

A Lyapunov Function for Switching Command of a DC–DC Power Converter With an LC Input Filter

This paper describes a method to control a dc-dc switching power converter with an LC input filter working under continuous conduction mode. It is known that the interaction between the low-pass filter and the tightly controlled switching converter occurs, and it might lead to an instability operation. The idea of this method relies on the Lyapunov stability criterion. The switching command of this control is defined by the manner of pre-evaluating the stability of the controlled system. All state variables are controlled in the same time. Therefore, the responses of this controlled system are fast while guaranteeing a stable operation. The proposed control is applied to a boost converter to demonstrate the implementation and its performance. The simulation and experimental results validate the proposed control approach.

CCM–DCM Power-Multiplexed Control Scheme for Single-Inductor Multiple-Output DC–DC Power Converter With No Cross Regulation

Single-inductor multiple-output (SIMO) switching dc-dc power converter architecture is a cost-effective alternative to multiple individual switching power converters solution in many power distribution system applications where multiple voltage rails are required at reduced cost. However, with multiple output voltage rails coupled to the same switching node, the SIMO power converters suffer from cross regulation between the multiple outputs, which complicates the closed-loop controller design of the SIMO converter and degrades regulation performance. In this paper, a power-multiplexed (PM) control scheme is proposed aiming to completely decouple the operations of multiple outputs from one another. The proposed PM control scheme results in eliminating the cross regulation among the multiple outputs while maintaining desired voltage regulation performance for each output under both steady-state and dynamic operations. Low-cost microcontroller or analog circuitries can be used to implement the proposed controller. Experimental proof of concept prototype results verify the feasibility and advantages of the proposed controller.

Optimization of Synchronous Non-Isolated Bidirectional DC-DC Switching Power Converter

This paper presents a high-efficiency non-isolated synchronous bidirectional DC-DC switching power converter. The circuit is made to operate in Synchronous Discontinuous Conduction Mode (SDCM)/Forced Continuous Conduction Mode (FCCM) of operation for minimum inductor value, to reduce the size, weight and cost of the converter. A snubber capacitor is used across the switch to minimize turn-off loss. The power dissipation through snubber capacitor and inductor is minimized by proper selection of their value, which improves the efficiency of the converter. Complementary gate signals are used to control the ON and OFF of main and auxiliary switch. By use of SDCM of operation, complementary gate signals control scheme and snubber capacitor, turn-on loss and parasitic ringing effect is minimized. State space averaging method is used to obtain control-to-current transfer function module. Using the transfer function module, Proportional Integral Derivative (PID) controller is tuned using PID tuner software, available in MATLAB simulink control design block to regulate load voltage and load current for change in inductor reference current (I*), change in load resistance and change in input voltage. The modules are verified using MATLAB simulink simulator.

Modeling and Evaluation of Carbon-Nanotube-Based Integrated Power Inductor for On-Chip Switching Power Converters

This paper presents a nanotechnology-based high power-density and low-power-loss on-chip power inductor for dc-dc switching power converters. This power inductor utilizes a composite of bundled multiwalled (concentric) carbon nanotubes (BMWCNTs) and Fe (iron) in order to achieve high performance in a small size. Titanium (Ti) is then added as a coating material on the BMWCNT-based power inductor. The BMWCNT-based power inductor with a single layer and three turns occupies an area of 200 μm × 200 μm. It exhibits an inductance of 206 nH, a quality factor of 427 at 20 MHz, and a dc rated current of 100 mA. The power inductor size and the performance characteristics are competitive with state-of-the-art power inductors. The design, analysis, modeling, and simulation results of the BMWCNT-based power inductor are presented and compared with state-of-the-art conventional power inductors from the literature.

Design of low-power high-frequency digital controlled DC-DC switching power converter

This paper models a low-power high-frequency digitally controlled synchronous rectifier (SR) buck converter. The converter is a hybrid system with three operation modes. Digital PID controler is used. Key problems such as quantization resolution of digital pulse-width modulation (DPWM) and steady-state limit cycles of digital control switching model power supply (SMPS) are discussed, with corresponding solutions presented. Simulation of a digital control synchronous buck is performed with a fixed-point algorithm. The results show that the described approach enables high-speed dynamic performance.

Digital PWM controller with one-bit noise-shaping interface

Conventionally, pulse width modulation (PWM) controllers for DC-DC switching power converters have been implemented in pure analog circuits. However, recent research showed the possibility of digit...

Novel Digital Controller with Static Model Reference for Switching DC-DC Power Converters

It is often observed that the operation of the digitally controlled dc-dc power converter becomes unstable when the relatively large integral coefficient is used to extend the regulation range of the output voltage to handle variations in the input voltage and load. This paper presents a novel digital controller with static model reference for switching dc-dc power converters to improve the performance characteristics and discusses its design-oriented analysis in the steady-state characteristics. It is clarified theoretically and experimentally that using the static model reference, the wide regulation range of the output voltage to handle variations in the input voltage and load current can be achieved with the appropriate small integral coefficient in the digital P-I-D controller. Therefore, since the integral coefficient is selected to cover the maximum instantaneous variation value of the static reference model, the integral coefficient is small and the operation is always stable.

Current-mode analogue integrated circuit for sliding-mode control of switching power converters

An analogue integrated circuit designed to implement sliding-mode control laws for high frequency switching DC-DC power converters is presented. The circuit operates in current-mode, providing high speed, modularity and the capability of including compensating dynamics. Experimental results for a 0.8 µm complementary metal-oxide-semiconductor (CMOS) technology prototype validate the high-speed functionality of the proposed sliding-mode controller implementation.

Recognition of dynamic patterns in DC-DC switching converters

Techniques for analyzing the dynamic patterns of power flow in high-frequency DC-DC switching power converters are developed. Emphasis is placed on exploring methods for developing reduced-order instantaneous and averaged models. of power electronic circuits for simulation, analysis, and control design. Tools from selective modal analysis are used to develop the dynamic pattern recognition algorithm that facilitates the classification of circuit modules.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>