Output Ripple Research Articles

A Two-Phase Three-Level Buck DC–DC Converter With X-Connected Flying Capacitors for Current Balancing

This letter presents a two-phase three-level (2P3L) buck converter with cross-connected flying capacitors ( $\text{X-}C_{\mathrm{ FLY}}$ ). The proposed converter suppresses the unbalanced inductor currents in two-phase operation, by alternately connecting the flying capacitors to across the branches. Meanwhile, three-level operation reduces the required inductance with lower inductor voltage, together with two-phase operation, helping to achieve fast transient response and small output ripple. Here, we design the power stage and feedback loop aiming for a bandwidth of 10 MHz. Then, the proposed 2P3L buck converter with $\text{X-}C_{\mathrm{ FLY}}$ fabricated and validated in 65-nm standard CMOS achieves a low unbalanced current of about 5 mA, and a small output ripple of 50 mV at a load current of 110 mA, using only 1-nF output capacitor. The measured peak efficiency is 86%. Besides, it can track fast 10-MHz 64QAM LTE envelope signal.

Design and simulation of a 1 MeV, 100 mA parallel-fed capacitive coupled cascade industrial accelerator

The construction of indigenous parallel-fed capacitive coupled cascade accelerators for industrial electron beam processing has been taken up at accelerator division of NSTRI at Iran atomic energy organization. This machine has been previously developed by Radiation Dynamics Inc. (RDI), IBA Industrial and High Voltage Engineering Europa B.V. (HVE) companies. Parallel-fed capacitive coupled cascade generators are reliable and high current sources of DC accelerators with many scientific, medical and industrial applications. We have selected this mechine because of some superiorities of that in comparison with many existing accelerators. These superiorities are as follows: compactness, simplicity, cheapness, having typically higher amount of beam current, wide range of beam energy and addressing many areas of applications. In this article, the main parts of a 1MeV, 100mA parallel-fed cascade industrial accelerator have been analyzed, designed and simulated. These parts are the electron gun, accelerating tube, voltage multiplier column (VMC) and some of the other components of the VMC. The electron gun is of a diode type with the Pierce configuration. Two electron guns with different cathode shapes have been designed and compared with each other. The intended cathode is a Dispenser type with a tungsten heater and porous tungsten matrix wich is impregnated with LaB6 and works in ambient vacuum of 10–7 Torr. The required current in our accelerator is about 100mA. For the next step, the accelerating tubes with different electrode geometries have been designed, simulated and compared with each other and the best geometry has been selected. For the VMC, we have tried to achieve a low ripple output DC voltage. The VMC has been analyzed and simulated with PSpice simulation software and optimum values of different parameters were achieved. We have tried to get the optimum values of the PSpice simulations by a mechanical design in CST Particle studio. At the end, the parameters of the mechanically designed VMC had a good accordance with the results from PSpice.

Design and construction of a digital solar array simulator with fast dynamics and high performance

This paper presents the hardware implementation of a digital solar array simulator (DSAS) to evaluate and validate the operation of maximum power point tracking (MPPT) algorithms and photovoltaic (PV) inverters used in solar power conditioning systems (SPCSs). The required criteria for designing and setting up a genuine SAS are high-accuracy static behavior, fast transient response, and high flexibility for the emulation of the different PV modules. A four-phase interleaved buck converter is chosen as the proposed power stage of the SAS because of its advantages of power management, filtering reduction requirements, and output ripple minimization. The proposed SAS control system has been digitally implemented by a digital signal processor (DSP)-based controller, in which third-order integral-lead compensator and resistive feedback method have been chosen to reproduce precise and stable operating points. Experimental results confirm the proper and satisfactory steady-state operation and dynamic response of the proposed DSAS.

Multivariable extremum-seeking by periodic switching functions with application to Raman optical amplifiers

A periodic switching function based extremum-seeking sliding-mode control strategy is addressed for uncertain nonlinear systems. We generalize previous results to a more challenging multivariable scenario, where the diagonal dominance condition is relaxed and can now be understood as a triangular dominance condition, which is significantly less restrictive. As an essential advantage over earlier results in the literature, the complete global convergence proof (with respect to the closed-loop initial conditions) of the overall multi-input multi-output (MIMO) closed-loop system is provided, rather than local stability results. The practical application of the proposed multivariable controller is exemplified through the optimization problem of the output signal power spectrum of Raman optical amplifiers. From a practical point of view, the extremum-seeking scheme enables the automatic adjustment of the control pump power signals in the presence of plant uncertainties, guaranteeing a flat power spectrum of the downstream data signals. Using a multi-objective approach, we develop the optimization algorithm to achieve this goal by simultaneously minimizing the output ripple and the deviation from some desired power level. The convergence analysis and control design are carried out in the presence of uncertainties, and the algorithm performance is tested through numerical examples, where a particular optical communication system with 32 channels is considered. This numerical example uses model parameters acquired experimentally and a representative fiber model, such that the results are close to what is expected to find in a practical implementation.

Fully Differential Chopper-Stabilized Multipath Current-Feedback Instrumentation Amplifier with R-2R DAC Offset Adjustment for Resistive Bridge Sensors

A fully differential multipath current-feedback instrumentation amplifier (CFIA) for a resistive bridge sensor readout integrated circuit (IC) is proposed. To reduce the CFIA’s own offset and 1/f noise, a chopper stabilization technique is implemented. To attenuate the output ripple caused by chopper up-modulation, a ripple reduction loop (RRL) is employed. A multipath architecture is implemented to compensate for the notch in the chopping frequency band of the transfer function. To prevent performance degradation resulting from external offset, a 12-bit R-2R digital-to-analog converter (DAC) is employed. The proposed CFIA has an adjustable gain of 16–44 dB with 5-bit programmable resistors. The proposed resistive sensor readout IC is implemented in a 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. The CFIA draws 169 μA currents from a 3.3 V supply. The simulated input-referred noise and noise efficiency factor (NEF) are 28.3 nV/√Hz and 14.2, respectively. The simulated common-mode rejection ratio (CMRR) is 162 dB, and the power supply rejection ratio (PSRR) is 112 dB.

Analysis and Design of Continuous-Time Multivariable Periodic Controllers: An $\mathcal {H}_{\infty }$/LTR-Based Approach

This article proposes a new high-frequency continuous-time two degrees of freedom (DOF) periodic control scheme to compensate linear time-invariant (LTI), square/nonsquare multivariable plants. The proposed scheme is more effective when the plant is nonminimum phase, or has more inputs than outputs. It is proved that, in averaged sense, the design of periodic controller can be recast as designing a 2-DOF LTI controller for an equivalent LTI plant. The conditions for which this equivalent plant becomes minimum phase are also obtained. When this plant is minimum phase and has no more inputs than outputs, the synthesis of the above-mentioned LTI controller is carried out using an linear matrix inequality-based $\mathcal {H}_{\infty }$ /loop transfer recovery (LTR) approach to achieve linear quadratic regulator (LQR) loop behavior asymptotically. The design method being based on LTR, the reference-input-to-output transfer function of the averaged compensated system becomes same as that using LQR. The periodic controller is shown to exhibit negligible ripples in the plant output, but $O(1)$ ripples in control input. Suitable examples are considered to show the superiority of the proposed control.

A Nine-Level Inverter for Low-Voltage Applications

A novel nine-level inverter topology for low-voltage applications is proposed in this paper. Each phase of the inverter is composed of a T-type three‐level cell and an active neutral point clamp three‐level cell. The operation principles and current conduction paths are analyzed in detail and phase-disposition sinusoidal pulsewidth modulation is used to balance voltages of flying capacitors and neutral point. The mathematical relationship between the capacitance and the desired ripple in the inverter output is established to select the intermediate capacitance value. Compared with other nine-level inverters suitable for low-voltage applications, the proposed inverter has advantages in a number of gate drivers, a number of dc sources, and efficiency. Simulation and experimental results under different settings of modulation index, power factor, output frequency, and load are presented to verify the effectiveness and performances of the proposed inverter.

Fractional techniques to characterize non-solid aluminum electrolytic capacitors for power electronic applications

Non-solid aluminum electrolytic capacitors are one type of reliability-critical components, and they are widely adopted in power electronic converters. The capacitance and equivalent series resistance of these components have significant effects on the performance and reliability of power electronic systems. In this work, by exploring the electrochemical principles of aluminum electrolytic capacitors, the fractional-order (FO) characteristics of the capacitors are revealed, according to which the frequency-dependent parameters of this kind of components are expressed by FO models, while the parameters of the models are estimated by a multi-objective optimization algorithm. Under the same conditions such as the number of arguments supplied and optimization algorithm, the proposed models perform better. Additionally, to show further applications of fractional techniques, a brief example on the output ripple analysis of DC–DC converters is offered, in which one of the proposed FO models of the capacitor is adopted. The effectiveness and superiority of the techniques for predicting the states of the converters are confirmed by comparison with traditional models.

A Regulated Charge Pump with Extremely Low Output Ripple

In this paper, we present a regulated charge pump with extremely low output ripple (<1 mV) that can be used for accurate programming of nonvolatile memory. We present a technique to include a low-drop-out regulator inside the charge-pump regulation loop to reduce the ripple. This charge pump was fabricated in a 0.35 μ m standard CMOS process. The die area of this charge pump is 0.163 mm 2 . While operating from a 2.5 V supply, this charge pump generates regulated voltages up to 10 V.

Circuit Topology Analysis for LED Lighting and its Formulation Development

Light emitted diode (LED) is becoming more popular in the illumination field, and the design of LED lighting is generally made to provide illumination at lower power usage, helping save energy. A power electronic converter is needed to provide the power conversion for these LEDs to meet high efficiency, reduce components, and have low voltage ripple magnitude. The power supply for LED is revisited in this paper. The LEDs connected in series with diode, transistor, or inductor paths are examined. The formulation for each of the cases is described, including the classical converters of buck, boost, buck–boost, and Ćuk. The circuit reductions of the classic circuit, circuit without the capacitor, and without a freewheeling diode are studied. Using LED to replace freewheeling diodes is proposed for circuit component reduction. General equations for different connection paths have been developed. The efficiency and output ripple amplitude of the proposed power converters are investigated. Analytical study shows that the efficiency of proposed circuits can be high and voltage ripple magnitude of proposed circuits can be low. The results show that the proposed circuit topologies can be easily adapted to design LED lighting, which can meet the criteria of high efficiency, minimum components, and low-voltage ripple magnitude at the same time.

Fuzzy Logic Controlled SEPIC Re-Lift Converter System - A Comparative Study

Voltage lift cascaded DC/DC converters are generally used to feed low power DC drives and batteries. This paper deals with the modelling, the simulation and the comparison of voltage lifted Single Ended Primary Inductor Converter (SEPIC) cascaded soft switched converter systems. The objective of this work is to improve the voltage gain and the efficiency of the voltage lifted SEPIC converter. Auxiliary switch with capacitor clamping is added in order to obtain the soft switching. SEPIC in self-lift and re-lift modes are simulated and the corresponding results are presented. The performance of the converter is studied in terms of output power and ripple voltage. Design and simulation results are presented in order to identify a cascaded system with high power output. The comparative study is presented in order to demonstrate the reduction in the ripple in the output voltage. The advantages of the proposed converter are high voltage gain, reduced switching loss and low electromagnetic interference (EMI). The open loop systems with fluctuating input voltages are simulated. Closed loop systems with proportional integral controller and Fuzzy Logic Controller (FLC) are simulated and their results are compared. Comparing the results, it can be observed that the time response has been improved in terms of settling time and steady state error.

All-GaN Power Integration: Devices to Functional Subcircuits and Converter ICs

This article reports the Au-free GaN power integration platform and a complete integration scheme from devices to functional subcircuits and to application-oriented GaN converter ICs. The design and experimental demonstration of all-GaN dc-dc converter IC with high level of integration is presented. Through the developed GaN power integration platform, devices are monolithically integrated and functional subcircuits are demonstrated, which have realized expected application-oriented functions and are feasible for high-level integration. The all-GaN converter IC with monolithically integrated high-side gate driver, pulse-width modulation (PWM) feedback controller, and overcurrent protection circuits are proposed, numerically analyzed, experimentally demonstrated, and characterized. It can realize stable 10-V output with constant output ripples below 4% from 15-30-V input line voltage. Stable output with constant ripples can be maintained according to the designed feedback control when input and load conditions are abruptly changed. When subjected to over-current incident, the converter IC can be protected according to the desired over-current threshold values within one duty cycle period. The developed all-GaN power integration platform, together with functional subcircuits and dc-dc converter IC, can be a practical verification of all-GaN IC scheme oriented toward power conversion application, and a useful reference for all-GaN IC designs.

PV based high level hybrid multilevel inverter

This paper presents a PV based high level hybrid multilevel inverter. SEPIC converter is the technologically advanced converter derived from the buck-boost converter. The proposed scheme is used in the SEPIC-converter to eradicate the output ripples and well enhance the output voltage level. Cascaded H Bridge and Neutral point clamped (NPC) inverter topologies are combined to obtain 127 level of output voltage using reduced number of switches and DC sources. To increasing the voltage level, Total Harmonic Distortion (THD) can be reduced and hence reduction in size of the filter. Simulation work is done using MATLAB and then to verify the performance of suggested scheme.

Design of Adjustable Switching Power Supply with Current Type Single-Ended Flyback Output

This study is based on the UC3845 controller, designed a flyback switching power supply, which has a wide input voltage range, high output voltage accuracy, and high load regulation. According to the characteristics of flyback switching power supply and UC3845, adding filter circuit, a feedback circuit, protection circuit, etc., develop a single-ended flyback switching power supply with adjustable output, stable and reliable, and high efficiency. According to the simulation results, it can be seen that the designed switching power supply has high output voltage accuracy, and the input voltage in the range of 200V∼240V, the accuracy of the output voltage is kept within 1.3%; the voltage adjustment is less than 1%, The output ripple factor is kept below 0.09%, and the output voltage is adjustable.

Disturbance Analysis and Implementation of High Voltage Gain Non-Isolated DC-DC Converter for Renewable Applications

A modified high gain single switch high-voltage converter is presented in this paper. The proposed converter is a blend of a voltage tripler and a SEPIC-boost mode converter. Its operational modes are presented in detail. This converter has advantages that include a single switch, reduced component stress and size, and reduced ripple output voltage and input ripple current. The simulation results of the suggested converter and a conventional multilevel SEPIC converter are presented. The prototype of a 30 V to 400 V input, 400 W output is developed and the performance of the designed topology is evaluated. The theoretical and experimental results conclude that this converter is suitable for high-voltage applications.

Modeling and adaptive control of modified LUO converter

This study presents the implementation and modeling of adaptive control of a modified LUO converter which eventually result in the progression of the dynamic functioning of power converter. In general, LUO converters include two series, which are major and additional series. DC-DC conversion has been executed to employing LUO converter and fly back converter. It uses VL technique in order that output voltage is intensified in every stage. The most important advantages of the proposed structure are that it has the benefits of the switched capacitor and as well VL technique. PI Controller has been used in order to simulate the experimental set-up. Embedded C programming was employed to create the PI controller set up. Kp and Ki values have been calculated using the Ziegler Nichols technique. Simulation has been done using MATLAB. Boosting has been accomplished using the voltage lifting technique. Findings emphasized that LUO converters are likely to improve the power transfer gain in energy progression. Also, the proposed LUO converter in the research has been proven to be able to provide a topology which eventually lessens the output ripple and losses. To verify the proposed DC-DC power converter performance, the simulation and experimental setup has been tested with certain parameters, including source voltage and current, capacitors, etc. Several forms of LUO converter voltage lifting (VL) methods performance including ultra-lift, re-lift and self-lift have been compared with that of the performance of the proposed design. Comparison between different voltage gains of LUO converter topologies have also been carried out in this research. The results reveal that the proposed design gives better boost in voltage, compared with that of the existing designs.

A Ripple Reduction Method for Switched-Capacitor DC–DC Voltage Converter Using Fully Digital Resistance Modulation

The output ripple of switched-capacitor dc–dc voltage converter (SCVC) severely degrades the energy efficiency, performance, and robustness of the VLSI system. In this paper, a fully digital resistance modulation (FDRM) technique is proposed to reduce the output ripple of SCVC, which is scalable and compatible with the exiting ripple reduction methods. The proposed FDRM technique suppresses the impulsive charging and discharging effects in the SCVC operation by dynamically modulating its equivalent switch resistances, resulting in a reduced output ripple. The FDRM control signals can be generated from simple logic gates with the interleaved clock signals, realizing a low implementation complexity. The proposed FDRM technique was verified by a fully integrated SCVC in 180-nm CMOS process with an active area of 0.93 mm2. The measurement results show that the SCVC prototype with the proposed FDRM technique achieves an averaged ripple reduction of 31.6% and a peak conversion efficiency of 88.96% under a loading range of 95–190 $\mu \text{A}$ .

Fuzzy Logic Based Controller For Buck Converter

This research aims to make buck converter prototype for PLTS system by using fuzzy logic controller. Buck converter is required in the PLTS system if the required unidirectional voltage is smaller than the output voltage of the solar cell. Buck converter used to convert 24 Volt dc voltage to 12 Volt dc with 60 watt capability. While fuzzy logic controller is used to improve buck converter performance based on pulse generation technique for switching. The application of fuzzy logic method is expected to improve the performance of the system by maintaining the stability of buck converter output voltage of 12 volts and reduce the output ripple value. Atmega8535 microcontroller is used to generate PWM pulses for switching on power circuits. The results obtained from the test using a 100 Ohm 5 Watt load obtained the buck converter output voltage of 12.4 Volt.

Speed Control of IDDB and SVPWM Controlled PMSM Motor in Fuel Cell Based Electrical Vehicle

The prominence of Fuel Cell Electric Vehicles (FCEV) has been soaring in technologies being implemented in electric automobiles due to their main advantages of eco-friendly nature, bountiful efficiency and extreme reliability .In this paper we deal with the simulation of electric vehicles that are fuel cell based. The voltage at the output stack of fuel cell is considerably low, hence it is increased by rendering IDDB converter with closed loop control. This type of boost converter with closed loop control is also utilized to priorate the converter output voltage consistent regardless of the pressure levels in the fuel cell. The output of the boost converter is coupled to the inverter for developing AC to run PMSM. Gating signals are produced to the inverter by the use of Space Vector PWM technique and the inverter output is supplied to the PMSM drive by means of an LC filter in order to diminish the ripples in the inverter output . In this work, in order to achieve better performance above induction motors such as higher speed, torque efficiency PMSM drive has been proposed . The results are verified by simulation techniques using MATLAB/Simulink.

Simulation Analysis of Boost Converter Using Naïve Bayes Classifier Algorithm

The DC-DC boost converters theoretically produces high step up voltage gain at high duty cycle. But in practice, Multilevel DC-DC boost converter fails to achieve higher power conversion efficiency due to switching losses. The inductor required the maximum duty ratio for providing better output voltage. More ripples in outputs will reduce the converter efficiency. By using individual soft-switching circuit in PWM results with higher cost and shows complexity of the circuit. The objective of the research work is to analyse and design a converter for Higher Efficiency and less ripple output voltage, suitable for the application in Renewable Energy related systems. To improve the efficiency of DC-DC converter in high power applications using, “Bayes Soft Switching Interleaved” Boost Converter (BSS-IBC). To compare performance of above technology based on switching time, ripple, power output and converter efficiency using MATLAB.