Peak Current Control Research Articles

Transformer-Less Seven-Level Inverter with Triple Boosting Capability and Common Ground

This paper proposes a single-phase, transformer-less, seven-level inverter that utilizes eight switches, three capacitors, and two diodes to produce seven voltage levels with triple boosting ability. The availability of the common-ground point eliminates the leakage current in PV applications. The proposed Transformer-Less Triple-Boosting Seven-Level Inverter (TLTB7LI) has the ability to feed different types of loads from non-unity to unity power factors. The voltage balancing of capacitors takes place naturally without the need for auxiliary circuits and complicated control strategies. This paper investigates the appropriateness of the proposed TLTB7LI for grid-connected application. The Peak Current Controller (PCC) is employed to generate the switching pulses and regulate the active/reactive power transfer between the converter and the output, which guarantees the high quality of injected current to the output. Moreover, the operational principles, its control technique, as well as the design procedure of the key components of the proposed inverter have been presented. The superiority of the proposed inverter over existing counterparts has been verified through comparative analysis. The simulation and experimental analysis validated the proper operation of the proposed TLTB7LI.

Feedforward Compensation for Phase-Shifted Full-Bridge DC–DC Converter Under Peak Current Mode Control

Feedforward Compensation for Phase-Shifted Full-Bridge DC–DC Converter Under Peak Current Mode Control

Peak current control of grid-feeding inverter with low voltage ride-through capability

Peak current control of grid-feeding inverter with low voltage ride-through capability

Low Distortion Boost Rectifier Discontinuous Conduction Mode with Peak Current Mode Control for Wind Power Systems

This work presents a Three-Phase Boost Rectifier with peak current mode control operated in Discontinuous Conduction Mode working as the input stage of wind power systems based on Permanent Magnet Synchronous Generators with variable speed operation. It is shown that the DCM operation significantly reduces the Total Harmonics Distortion of the currents in the Permanent Magnet Synchronous Generator, so that the vibrations and mechanical stress of the generator is minimized. The characteristics of the DCM Boost rectifier are studied considering: 1) The resistance in series of the inductors; 2) The modeling and adjustment of the current injected control yielding a stable loop; 3) The design of an input filter that reduces the switching noise in the currents of the generator.

Design and Simulation of Supercapacitor Energy Storage System

STATCOMs are widely used to enhance power system stability. They can exchange reactive power with the power system, but they have limited ability to exchange real power because they don’t include energy storage devices. STATCOMs coupled with energy storage devices such as batteries have been introduced to improve their ability to exchange real power. However, batteries have a limitation in their maximum deliverable power because of the slow chemical process required to release their energy. The trend now is to use supercapacitor energy storage systems "SCESS" as energy storage for STATCOMS. Supercapacitors have lower energy storage but higher power exchanging capability compared to batteries. This paper presents the analysis, design, and control of a supercapacitor energy storage system (SCESS) for a STATCOM. A peak current mode controller is used to control the SCESS system. Simulation results of the SCESS system are presented which indicate excellent performance of the proposed SCESS system.

Artificial Intelligence-Enhanced Peak Current Mode Control for Enhanced Power Regulation in High Power High Frequency Electrosurgical Generators

Artificial Intelligence-Enhanced Peak Current Mode Control for Enhanced Power Regulation in High Power High Frequency Electrosurgical Generators

Modeling and design of a photovoltaic‐fed single‐ended primary‐inductor converter for maximum power point tracking with current mode control

SummaryIn this work, the control of a Single‐Ended Primary‐Inductor Converter (SEPIC) supplied from a photovoltaic energy source and linked at its output to a DC current sink is addressed. The system is used for maximum power point tracking under varying environmental conditions. A strategy based on two loops of control is considered. A peak current mode controller is used for the inner loop, and a Proportional‐Integral (PI) controller is used for the outer voltage loop. Then, a comprehensive time‐domain and frequency‐domain modeling of the inner loop is theoretically addressed and then verified by the switched model of the system implemented in PSIM© software. The obtained results show that the system exhibits accurate tracking of the desired PV voltage while guaranteeing a fast maximum power point tracking under sudden changes in the environmental conditions. The mathematical modeling, design procedures, and the numerical simulations are validated using experimental results obtained from a laboratory prototype.

Small-Signal Modeling and Analysis of Converter Interactivity in 48 V DC Grid

Due to the flexibility of realization in decentralized form, environmentally genial, and the easy integration with renewable energy sources, storage units, and loads, the direct current (DC) microgrid has shaped as a subject matter worldwide. In a DC microgrid structure, the concurrent operation among multiple DC-DC converters, connected in parallel fashion across the common DC bus, realizes substantially with the average current information-based droop control technique. However, such control logic requires two minimal controllers with an inter-reliant design process to implement the overall control action. Considering the coupling effect during converter operation, this paper analyses the implementation of a mixed-signal peak current information-based droop control logic for the parallel connected converter system. A thorough small signal and switch-based modeling process for the interconnected systems are carried out with consideration of resistive and constant power loads. Adaptability to modeling with a first-order approximation-based approach makes the methodology easy for the design of the controller and stability analysis process in a parallel connected converter system. The veracity of the designed model is verified using simulation studies. A hardware prototype with two boost converters operating in parallel and feeding power to a resistive load and a buck converter (behaving as a constant power load) is fabricated to study the performance of the designed controller, along with the effect of different transient events on overall system performance.

Microcontroller-Based Trapezoidal Slope Compensation Technique for Peak Current Mode Control at MHz Frequencies

Slope compensation is necessary for the peak cur-rent mode control technique to ensure the stability of the power converter. Micro-controllers (μCs) existing in the market implement the slope compensation using built-in digital to analog converters (DACs). DACs exhibit finite transient times, which can be negligible when the μCs are used to control the power converters at switching frequencies in the order of a few hundreds of kHz. However, for high device switching frequency (HDSF) operation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\geq 1\, \rm{MHz}$</tex-math></inline-formula> ), the DAC transient time becomes significant and can make it difficult, if not impossible, to achieve the conventional ramp slope compensation. Hence, in this paper, a novel concept of ‘trapezoidal’ slope compensation is proposed by considering the transient time of the μC. A detailed analysis is performed to understand the effect of the transient period on the converter stability. The proposed technique is validated with an experimental prototype of 400 W at 1 MHz switching frequency and it is shown to ensure stability of the converter at all operating points within the specification.

Modeling and Nonlinear Dynamic Analysis of Cascaded DC–DC Converter Systems Based on Simplified Discrete Mapping

As a basic structure of the distributed power systems, cascaded DC-DC converter systems have attracted a lot of attention. However, due to the interaction between the sub-converters, classic methods for modeling cascaded systems are either not accurate enough, such as state-space averaging model, or not simple enough, such as discrete-time mapping model, especially the systems with different switching frequencies. To overcome this drawback, a simplified discrete-time mapping modeling method for cascaded DC-DC converter systems is proposed in this paper. Based on the idea of state-space average, the original problem is simplified to modeling cascaded DC-DC converter systems with same switching frequencies. The proposed method is able to predict the dynamic properties of the system at all stages, such as slow-scale and fast-scale instabilities. Then, two-stage cascaded boost converter with different switching frequencies under peak current double loop control is taken as an example to present the simplified discrete-time mapping model. Finally, the effectiveness of the proposed method is verified by simulations and experiments.

고효율 및 슬림형 전압 평형 3-레벨 벅 컨버터

The 3-level buck converter features half the switch voltage stress of the conventional synchronous buck converter. The operating frequency of the output inductor is also twice the switching frequency. The slope of the inductor current can be reduced as well due to the flying capacitor voltage, which can greatly reduce the size of the output inductor. Therefore, the 3-level buck converter can achieve high efficiency and high power density. The flying capacitor voltage must be half the input voltage to achieve the abovementioned strength. Most conventional control schemes for the voltage balance of the flying capacitor adopt a peak or valley current mode control method using real-time current sensing. Therefore, the control algorithm is complicated, and high performance and expensive digital controller is required. This study proposes an independent two-loop voltage mode control scheme that can guarantee the flying capacitor voltage to be half of the input voltage. The proposed control scheme can be simply implemented without current detection and does not require complicated control algorithms. Thus, simple and low-cost micro controller can be used. Experimental results from a rated prototype of 500 W are provided to verify the performance of the proposed control scheme.

A 20–200 mV, 92.52% peak efficiency, dual-mode boost converter with inductor peak-current-controlled and efficient ZCS for thermoelectric energy harvesting in bioimplantable devices

This paper presents a DC-DC boost converter in which a new inductor peak current control (IPCC) technique is adopted for efficient thermoelectric energy harvesting. The proposed technique reduces power loss and increases the efficiency of the boost converter. First, it is shown mathematically that the boost converter's minimum loss and maximum efficiency for each given input voltage occur at a certain unique amount of peak inductor current. It is also shown that by increasing the input power in the boost converter, the peak inductor current should be reduced to decrease the conduction loss and improve the efficiency. Then the proposed IPCC technique has been realized by using a smart switching frequency and duty cycle modulation. The proposed boost converter operates in discontinuous conduction mode (DCM) and critical conduction mode (CRM), decided by the input voltage range and maximum inductor current. To verify the technique, the circuit has been implemented in TSMC 0.18 μm standard CMOS process. Using zero current switching (ZCS) and IPCC techniques over an input range of 20–200 mV, the converter achieves a peak efficiency of 92.52% and 60.73% at 150 mV and 20 mV, respectively.

Expert knowledge-based peak current mode control of electrosurgical generators for improved output power regulation.

Electrosurgical generators (ESG) are widely used in medical procedures to cut and coagulate tissue. Accurate control of the output power is crucial for surgical success, but can be challenging to achieve. In this paper, a novel expert knowledge-based peak current mode controller (EK-PCMC) is proposed to regulate the output power of an ESG. The EK-PCMC leverages expert knowledge to adapt to changes in tissue impedance during surgical procedures. We compared the performance of the EK-PCMC with the classical peak current mode controller (PCMC) and fuzzy PID controller. The results demonstrate that the EK-PCMC significantly outperformed the PCMC, reducing the integral square error (ISE) and integral absolute error (IAE) by a factor of 3.88 and 4.86, respectively. In addition, the EK-PCMC outperformed the fuzzy PID controller in terms of transient response and steady-state performance. Our study highlights the effectiveness of the proposed EK-PCMC in improving the regulation of the output power of an ESG and improving surgical outcomes.

Design, implementation and performance evaluation of different digital control techniques for current controlled DC-DC Buck converter

The paper presents modelling, control architecture, analysis and design of digital compensators for single feedback-loop voltage mode control as well as two feedback-loop average current mode control and peak current mode control of current controlled DC-DC Buck converter operating in continuous conduction mode with output current as control variable. The compensators are derived using digital redesign approach, simulated on MATLAB, implemented as control algorithms on Texas Instruments' 32-bit TMS320F28069M microcontroller platform, and experimentally validated by testing with a laboratory prototype of current controlled Buck converter. Simulation and experimental results are discussed, compared and evaluated for converter output current performance in tracking reference current signal as well as in regulation against input voltage and load disturbances. Salient features of each control technique are identified and described to determine its suitability in applications of DC-DC converters requiring controlled output current.

Application of PCCS Method to PV Generation System with Half Bridge Inverter

A Power Conditioning System (PCS) for a PV power generation system obtains the maximum power from a photovoltaic (PV) array by Maximum Power Point Tracking (MPPT), but losses in the inverter are a factor in lowering the power obtained by the MPPT. The generation of harmonic currents is also a problem for PCS. This paper proposes the application of the Peak Current Control Switching (PCCS) method in PCS for PV Generation System using a half bridge inverter. The half bridge inverter improves efficiency by reducing the number of switching elements and further suppresses harmonic currents by controlling them using the PCCS method. In this paper, a comparative simulation of the conventional Hysteresis Current Control (HCC) method and the proposed PCCS method is performed using a half bridge inverter. The results of harmonic analysis and comparative simulation of total harmonic distortion (THD) show that the PCCS method generates harmonic components near the switching frequency, and that the proposed PCCS method always has a lower distortion rate than the conventional HCC method.

Dynamic behavior analysis of cascaded buck converter and boost converter system

PurposeCascaded DC-DC converters system is the main structure of distributed power system, and it has complex nonlinear phenomena during operation, which affect the power quality. Therefore, the dynamic behavior of the cascaded buck converter and boost converter system, as one of the typical cascaded DC-DC converters systems is analyzed.Design/methodology/approachFirstly, the studied cascaded system of the buck converter with peak current control and the boost converter with PI current control is introduced and its discrete modeling is built. Then, the Jacobian matrix of the cascaded system is calculated to research the stability when the parameter change. Finally, simulation by PSIM and experiments are carried out to verify the theoretical analysis.FindingsThe coexistence of fast and slow time scale bifurcations with the changes of reference current and input voltage are studied in the cascaded system, and using simulation analysis to further study the sensitivity of the inductor current of the front-stage converter and back-stage converter to different parameters.Originality/valueA discrete model of the cascaded buck converter and boost converter system is established, and its dynamic behavior is analyzed in detail for the first time.

Unified Model of Peak Current Mode Controlled Coupled SIDO Converters

Coupled inductor single-input–dual-output (CI-SIDO) converters are promising converters used in the applications that demand multiple voltage supplies due to their high efficiency and small volume. However, this class of converters suffers from poor cross-coupling and cross-regulation issues, which affects the dynamic performance and stability. These issues can be suppressed with peak current mode control because of its faster dynamic response. To design the controller and study dynamic performance, a small-signal model of the system is essential, which consists of a converter model and current modulator model. However, developing the current modulator model for PCM controlled CI-SIDO converters is challenging because it consists of two reference current for two inductor currents each consisting of three slopes. No literature is available that derives a unified model of PCM controlled CI-SIDO converters. Therefore, this article proposes a unified small-signal model for PCM controlled CI-SIDO converters. The proposed model is applicable to three topologies of CI-SIDO converters, i.e., CI-SIDO buck, CI-SIDO boost, CI-SIDO boost and buck converter. The proposed unified model is a useful tool to study the dynamic performances, stability, and design outer controllers. Finally, the accuracy of the proposed unified model is verified by performing simulation and experiment of PCM controlled CI-SIDO converters considering inner-loops closed.

An 8-A Sub-1ns Pulsed VCSEL Driver IC With Built-In Pulse Monitor and Automatic Peak Current Control for Direct Time-of-Flight Applications

An integrated laser diode driver for multi-junction vertical-cavity surface-emitting laser (VCSEL) arrays is presented in this brief. The driver chip, fabricated in 180nm bipolar-CMOS-DMOS (BCD) process, working under 12V supply, can pump more than 8A peak current into a triple-junction VCSEL array, producing up to 20.3W optical pulses. Measured optical pulses have tunable widths from 276ps to 2352ps with 120ps/160ps rise/fall time. When emitting 10MHz-frequency 960ps-width optical pulses with peak power ranging from 3.6W to 17.5W, the driver-VCSEL system has over 20% electrical-to-optical power conversion efficiency. The driver can record its output current waveform with a built-in pulse monitor. The peak data from the recorded waveform is used for automatic peak current control.

Hybrid Modulated DCDC Boost Converter for Wearable Devices

Wearable devices require power management systems to achieve high conversion efficiency over a wide range of load currents. Multi-mode mixed modulation can be used in DCDC converters to achieve high efficiency over a wide load current range. The DCDC boost converter proposed in this paper uses a hybrid modulation of DGM (Deep Green Control Mode), PCMC (Peak current mode control)-PFM (Pulse Frequency Modulation) and PCMC-PWM (Pulse Width Modulation). The converter switches smoothly from PCMC-PFM to PCMC-PWM mode under load-current-based conditions and without any mode selection module. The proposed DCDC boost converter is fabricated in a 0.18 μm CMOS process with a Die area of 1.24 × 0.78 μm2. The input voltage range is 0.8–5 V, the output voltage is 5 V, and the load current range is 5–300 mA. Experimental results show that the boost converter can achieve 94.7% peak efficiency. Efficiency of more than 90% can be achieved in the load current range of 30–300 mA.

Guest Editorial Special Issue on Power Electronics Systems for Aerospace Applications

Aerospace applications have been a major driver for the development of power electronics. The demand of light and efficient power supplies, common both for space and aeronautic applications, spearheaded the research and development efforts around switching mode power systems. Major seminal works in the field, such as those pioneered by Prof. R. D. Middlebrook, were developed under funding from National Aeronautics and Space Administration (NASA). Another example is that average current mode control or transconductance control was developed in the European Space Agency (ESA) laboratories while at the same time peak current mode control was invented in U.S. institutions.