Voltage Control Mode Research Articles

A 0.6V 119 dB High-CMRR Low-NEF PGA with common-mode voltage control for ECG recording

This paper proposes a programmable gain amplifier (PGA) with common-mode voltage control for ECG recording. In order to ensure that input common-mode interference (CMI) does not deteriorate amplifier performance, a novel common-mode voltage control module is proposed, which soaks up CMI and maintains the common-mode input within the expected range. Utilizing a standard 65 nm CMOS process, our PGA runs on a 0.6 V supply. This amplifier has a frequency response range of 10 Hz–57.0 kHz, a gain range of 0 dB–24 dB, and a noise efficiency factor (NEF) of 4.17. Its common-mode rejection ratio (CMRR) is over 119.2 dB, and input reference noise within the amplifier bandwidth is 6.6 μVrms.

Improved Voltage-Mode Control of a Buck-Boost Converter Based on Zeta Converter

Improved Voltage-Mode Control of a Buck-Boost Converter Based on Zeta Converter

Power Compatibility of Induction Motors in Industrial Grids Containing Synchronous Generators

Starting an induction motor causes voltage sag in the industrial grid that may disturb the operation of grid equipment. Direct-on-line starting is the simplest and most cost-effective method for starting induction motors, but also the most problematic. Large industries often use internal power plants with synchronous generators and starting powerful motors may impact the generator operations. The synchronous generators could be operated with the automatic or manual mode of voltage control. As the operation experience proves, the generator voltage control mode has a significant impact on the transient behaviours in the industrial power grid when starting a large induction motor. This article presents a case study of the synchronous generator tripping within a true medium-voltage industrial grid during the direct-on-line starting of a large induction motor driving the feed water pump. An analysis of the generator protection logs after the tripping showed that the synchronous generator was controlled in manual mode and its protection relay settings were exceeded. The transients initiated by induction motor starts were studied for possible configurations and operating conditions of the grid using a model developed on the Matlab/Simulink Software platform. The simulations have shown that concern about starting large motors in industrial grids containing internal synchronous generators needs to be solved considering the grid configurations and the coordination of generator protection and control devices.

Optimizing weighted voltage mode control for enhanced output cross-regulation in multi-output DC/DC converters

Weighted voltage mode control is a widely used method for regulating multiple output DC-DC converters, but inconsistent outcomes are often observed in design due to the complexity of the weighting variable optimization. This study proposes an optimization-based approach to accurately estimate the optimal weighting factors for improved output voltage regulation in multiple output forward DC-DC converters. Three optimization algorithms, the Imperialist Competitive Algorithm (ICA), Particle Swarm Optimization (PSO), and Ant Colony Optimization (ACO) are compared for their speed and accuracy in estimating the weighting factors. Additionally, a Fuzzy Logic Controller (FLC) is used to further reduce the overall steady-state error and improve transient characteristics. Simulations are performed using the MATLAB/Simulink software, and the results show that the proposed strategy significantly enhances output cross-regulation in multiple output forward DC-DC converters. The ICA-based weighting factor estimator is found to be the most effective algorithm among the three optimization algorithms tested. The main contribution of this study is to provide a more efficient and accurate method for estimating the weighting factors in multiple output forward DC-DC converters, which can lead to improved performance and reliability in various applications.

An Extended Continuation Power Flow Method for Static Voltage Stability Assessment of Renewable Power Generation-Penetrated Power Systems

The continuation power flow method (CPF) has been extensively used for obtaining the static voltage stability limit of power systems, which provides important guidance for the stable operation. However, the conventional CPF cannot account for the dynamic characteristics of renewable power generation, thus resulting in prominent errors for renewable power generation-penetrated power systems. In this paper, we investigate the static voltage stability assessment (SVSA) of power systems with high penetration of rgb0,0,0renewable power generation (RPG). An extended Jacobian matrix is firstly established by considering the dynamic characteristics of synchronous generators (SG) and renewable power generation in constant AC voltage control mode (CVRPG). Based on the extended Jacobian matrix, an extended CPF method is proposed for SVSA of the power system and a reactive power sensitivity index is proposed to indicate the voltage support capability of nodes. Simulation results show that the proposed extended CPF method has higher accuracy than conventional CPF in assessing the static voltage stability of power systems with high penetration of RPG. It is also revealed that that the voltage support capability of each node rises as the proportion coefficient is increases.

An integrated microfluidic platform for on-demand single droplet dispenser with high accuracy by electrohydrodynamic (EHD) printing technique

Droplet microfluidics has revolutionized single-cell analysis, allowing for ultra-high-throughput sorting of droplets to meet the demands of single-cell sorting. However, accurately and efficiently dispensing target droplets into specific containers for downstream analysis has remained a challenge. Here, we present an integrated microfluidic droplet dispenser based on the electrohydrodynamic (EHD) principle, capable of on-demand single droplet dispensing with high accuracy. Our system uses optical signal activation and EHD actuation to isolate and dispense droplets. The microfluidic droplet auto dispenser consists of four main modules: a pump-drive chip module, an optical automatic signal recognition module, a high voltage control module, and an automated X-Y translation stage module. By optimizing the chip structure and voltage parameter, this platform successfully isolates single Escherichia coli (E. coli) cells onto a Petri dish for downstream cultivation and heterogeneity analysis. In addition, the dispenser microfluidic system dispenses the sorted droplets in a "one droplet, one well" manner, providing an automated method for droplet interface from the micro- to macro- platform. This dispenser system provides a platform for phenotypic screening of single colony pick and single cell analysis

Current-mode PID controllers employing commercially available active components

This work describes two current-mode (CM) PID controllers using only two commercially active components, namely, current feedback operational amplifier (CFOA), and four passive components, i.e. two capacitors and two resistors. They have appropriate output and input impedance values, allowing them to be utilized in cascade connections without requiring a buffer circuit. Since all capacitors are grounded, it is suitable for integrated circuit (IC) technology. Moreover, the controllers can be easily modified to operate in voltage-mode (VM), transimpedance-mode (TIM), and transadmittance-mode (TAM) PID controllers. Using 0.18 µm CMOS parameters and the PSPICE program, the proposed circuits are simulated to verify the theoretical behavior. To demonstrate the viability of the circuits, experimental tests using commercially available AD844 integrated circuits are performed. The suggested PID circuits are alsoexperimental tested in a closed-loop system as an example.

A Nonlinear Multimode Controller for Seamless off-Grid of Energy Storage Inverter Under Unintentional Islanding

A nonlinear multimode controller (NMC) is proposed to achieve the whole process seamless off-grid of energy storage inverter (ESI) from the grid-connected state of current control mode (CCM) to the islanded state of voltage control mode (VCM) under unintentional islanding. Based on the presented design idea of intelligent equivalent substitution, NMC is composed of multimode voltage controller (MVC), multimode power compensator (MPC) and multimode current controller (MCC). MVC can control load voltage in islanding and maintain manipulated variables of load current in other modes. MPC can compensate the power flowing into grid and help inner loop reference value achieve the smooth drop, and also compensate for load current variation during grid-connection. MCC can track the given current during grid-connection and make MPC quickly obtain the compensation of load power variation. The reference values of inner loop are logically split into the output of MVC, MPC and MCC, so that the manipulated variables can be combined nonlinearly to achieve seamless off-grid of ESI under unintentional islanding. This paper also analyzes the ESI stability with NMC during the off-grid process, and analyzes the relationship between manipulated variables by simulations. Finally, the correctness and effectiveness of proposed NMC are verified by experiments.

FPGA CONTROLLED MPPT BASED BOOST CONVERTER FOR RENEWABLE ENERGY(SOLAR PV) POWER APPLICATIONS

This paper is proposing the Field Programmable Gate Array(FPGA) controlled multiphase DC-DC Boost. The proposed DC-DC boost converter is designed at high gain. The proposed converter is employed for higher power applications and controlled with the help of ZVS voltage mode control. The feasibility of proposed converting is verified by the simulation.

A Multi-Terminal Control Method for AC Grids Based on a Hybrid High-Voltage Direct Current with Cascaded MMC Converters

The hybrid high-voltage direct current (HVDC) transmission system with cascaded MMC converters has become a promising alternative for possessing the technical merits of both line-commuted converter (LCC) and voltage source converter (VSC), resulting in favorable characteristics and potential control of good prospect. This paper pays heightened attention to the feasible power and DC voltage control modes of a hybrid HVDC system; characteristics of master–slave control show higher flexibility than the LCC-VSC HVDC system, which demonstrates that the exceptional potential can serve to stability support the AC power grids. To optimize the control effect, besides damping level to attenuate power oscillations, the robustness suitable for various faults is also considered to obtain a multi-objective control problem. A detailed solution is proceeding using the TLS-ESPRIT identification algorithm and H2/H∞ hybrid robust control theory. This motivates multi-terminal controllers in the LCC rectifier and MMC inverters, which immensely improve the stability of both sending and receiving girds at the same time. According to the parameters of the actual hybrid HVDC project, the simulation model is established in PSCAD v4.6.2 software, and proposed control methods have been verified to satisfy damping objectives and perform well in multiple operating scenarios.

CONTROL OF VOLTAGE MODES AS A MEANS OF LOAD REGULATION

The article substantiates the regulation of power consumption modes of production facilities due to the management of voltage modes in the power supply system. It is shown that the regulation of electricity consumption with the help of consumers - regulators (CR) is quite often associated with losses that occur when the CR is turned off. Studies have shown that the management of voltage modes in the power supply system, which affects its level, can play a positive role in increasing the efficiency of the optimization of power consumption modes. It is shown that a comprehensive solution to the problem of power consumption management is expedient both at the expense of CR control and the influence on the voltage regimes of the power supply system. It is shown that the regulating effect of the load is characterized by static characteristics. Solving the problem of forming static characteristics is possible in two ways: through active experiments and based on the integration of static characteristics of individual consumers. Experimental studies were conducted to identify the static characteristics of the load. Experiments were carried out on transformers of the main step-down substation of the chemical industry enterprise, equipped with on-load tap-changers. Experimental static characteristics with linear changes are constructed. The parameters of the model are determined by the method of least squares. Constructed experimental and analytical static characteristics. The voltage mode control procedure for load regulation is implemented in the power consumption control system.

Experimental study on robust non‐fragile control of DC‐DC buck converter

AbstractThe presence of uncertainty in the converter model and controller parameters affects the system's stability and dynamic performance. This paper presents a comparative analysis of robust non‐fragile control based on (i) the Kharitonov method and (ii) the linear matrix inequality (LMI) technique so that the controller can cope with the effect of both uncertainties. The first approach based on Kharitonov theorem determines the robust performance region with guaranteed gain margin and phase margin under parametric uncertainty. The second approach (LMI technique) is based on devising a control law that can quadratically stabilize the closed‐loop system subject to uncertainties and satisfy the H∞ norm bound constraint on disturbance attenuation. Based on these two approaches, a robust non‐fragile PI controller is designed for voltage mode control of dc‐dc buck converter. The effectiveness of the control approaches is evaluated based on (i) robustness against large plant parameter perturbations and load disturbance and (ii) fragility against controller parameter perturbations. The performance of the designed controllers (using the Kharitonov method and the LMI technique) has been thoroughly evaluated and validated through simulation and experimental results.

Modeling and simulation of electrical generation systems based on PEM fuel cell-boost converter using a closed loop PI controller

This paper presents dynamic modeling and control of a proton exchange membrane fuel cell (PEMFC). The system consists of a DC–DC Boost converter, DC–DC regulator, and DC load. The goal of the research is the construction of an emulator of the PEM Fuel Cell stack, that of a device having the same behavior as the real system, and evaluates performances of a stand-alone power system. Since the fuel cell produces DC output voltage that is unregulated. PWM (pulse width modulated) DC–DC converters are assumed to operate in continuous-conduction mode and the PI compensator in the feedback path is designed with voltage-mode control to convert the unregulated voltage into a desired voltage level, during different load variations. The results show the output voltages of the studied PEMFC connected with PWM DC–DC converters during a DC load change are stable. A PEMFC system is modeled using Matlab/Simulink and is interfaced with the mathematical model of fuel cell and various waveforms are presented in the paper.

DC‐side stability analysis of grid‐tied converter with different control modes based on electrical torque analysis

AbstractThe DC‐side stability of the grid‐tied converter under different control modes is fully investigated using electrical torque analysis. The small‐signal model of a single converter connected to an ideal DC bus under various control modes is formulated. Accordingly, the damping and synchronising coefficient contributed by the DC network and controllers of grid‐tied converter are separately accessed using the electrical torque analysis method and the stabilising conditions of the grid‐tied converter operating under different control modes are further derived. The system stability mainly corresponds with DC network dynamics under constant active power control mode. On the contrary, the grid‐tied converter under constant DC‐link voltage control mode has no stability problem. Generally, elevating the DC‐link capacitance or decreasing the droop gain can greatly improve the stability margin reserve of the VSC‐HVDC links. In addition, the control gains of the classical PQ controller are proven to have limited impacts on DC‐side system stability. Finally, the results of numerical simulation prove the validity of the proposed stability analysis method and the stable boundary for the grid‐tied converter with different control modes.

Adaptive frequency deviation improvement using a voltage-controlled storage inverter in a weak distribution network with a high penetration level of stochastic photovoltaic power

With the rapid increase in the use of renewable energy sources, the strength of the power grid is reduced, which may lead to many weak distribution networks. The inertia of the weak distribution network decreases significantly, which leads to poor voltage quality. It means that the voltage and frequency are distorted and deviated. Battery storage can balance the frequent power disturbance and improve the frequency quality. However, it usually requires a central controller to dispatch the power in the current-controlled mode or respond natively with a fixed linear curve in voltage-controlled mode. The performance is poor when the power demand is in a wide range, which further deteriorates the frequency quality. To solve this problem, this paper proposes an adaptive frequency deviation improvement method for energy storage in the voltage-controlled mode. This method can change the power output characteristics of the storage inverter according to the magnitude and trend of power demand, where both frequency deviation and changing rate are used to shape the output power curve. A transfer function model for a voltage-controlled storage inverter is set up for theoretical analysis. Then, with the model, an adaptive frequency deviation improvement method is proposed with a fast response to power demand in a wide range. Finally, the results verify the effectiveness of the proposed method for frequency quality improvement with a high penetration level of stochastic photovoltaic power.

Design of Stable Digital V2 Controllers for the Synchronous Noninverting Buck–Boost Converter

The non-inverting buck-boost converter is suitable for battery powered applications as it can operate in buck, buck-boost, and boost modes. Traditional current mode and voltage mode controllers are generally employed to control it in closed loop. It is well established that a peak V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controller provides superior load-transient performance compared to conventional current mode and voltage mode controllers. However, a peak V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controller cannot be applied to the non-inverting buck-boost converter during boost and buck-boost modes because of its non-minimum phase behavior. This paper proposes a digital peak V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controller which can work effectively during all the modes. The proposed controller samples both the inductor current and output voltage at the rate of the switching frequency. Thus, digital implementation of this controller does not need high-speed ADCs. Unlike traditional peak V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> controllers, the proposed controller does not depend on effective series resistance (ESR) of the output capacitor. An average model-based small-signal model of the proposed controller is presented. Analysis shows that a sufficient current loop gain can make the system behave like a first order system. This enables the designer to employ a PI controller to achieve superior transient performance in all the modes. Furthermore, fast-scale stability analysis of the controller is carried out using approximate discrete-time models to derive an analytical stability boundary of slope compensation. A non-inverting buck-boost converter prototype is fabricated and the proposed controller is implemented using an FPGA platform. Experimental results show close correlation with the analysis.

A Current-Limiting Scheme for Voltage-Controlled Inverter Using Instantaneous Current to Generate Virtual Impedance

In this paper, a current-limiting scheme is proposed for the voltage-controlled inverter. The method utilizes instantaneous current to quickly activate a resistive fault-current-limiting virtual impedance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FCL</sub> ) to suppress the instantaneous impulse current and steady-state overload current, which can be directly integrated into the existing voltage-type control scheme. When a fault occurs, the inverter can be kept in the voltage control mode without mode switching. After the fault is cleared, it can automatically return to the normal operation mode. The parameter selection method of the current-limiting virtual impedance is analyzed, and the logic criterion for short-circuit fault clearance is presented to realize the automatic startup and exit of the current-limiting virtual impedance. Finally, the RT-LAB hardware in-loop experiment and the single-phase inverter platform experiment prove that the proposed current-limiting scheme can simplify the fault handling process and improve the anti-fault ability of the voltage-controlled inverter.

Analysis and Control of Chaos in Voltage Mode Control Superbuck Converter for Photovoltaic Systems

Superbuck converter is a high-order converter with complex nonlinear dynamic characteristics, such as bifurcation and chaos, which will affect the stability of photovoltaic power generation systems. In this paper, the nonlinear dynamics of the voltage mode control Superbuck converter are studied. Taking reference voltage, input voltage, and output voltage error amplification factor as bifurcation parameters, the evolution process of the system from a stable state to bifurcation to a chaotic state is analyzed. The bifurcation forms of the converter under three bifurcation parameters are all period-doubling bifurcations. In this paper, the linear sliding mode control method is used to suppress and clear the nonlinear phenomenon of the system so that the converter in the chaotic state and unstable operation state can be restored to a stable single-cycle state in about 0.6ms.

Robust current-mode control of bridgeless single-switch SEPIC PFC converter

In this paper, the nonlinear model of the bridgeless single-switch ac-dc single-ended primary-inductor converter (SEPIC) in discontinuous conduction mode is derived. In addition, a robust control method is introduced to accommodate the variations in input voltage and load current. The current-mode controlled power converter is designed to operate in buck and boost modes. The proposed closed-loop SEPIC converter is simulated in MATLAB to validate the design approach. The current-mode control scheme is also compared with the conventional voltage-mode controller. It is confirmed that the proposed control scheme exhibits precise tracking performance and enhanced transient response under large disturbances.

Cuk PFC Converter Based on Variable Inductor

When the input inductor operates in discontinuous current mode (DCM), the Cuk converter can automatically achieve power factor correction (PFC) function with only a simple voltage mode control loop. However, the conventional Cuk PFC converter suffers from high intermediate capacitor voltage because of the lack of feedback of the intermediate capacitor voltage and relatively low power factor (PF). In this paper, a Cuk PFC converter using variable inductor which varies with the transient rectified input voltage is proposed to enhance the PF and reduce the intermediate capacitor voltage by injecting a controlled DC bias current into the auxiliary winding of the variable input inductor. The operating principles of the proposed Cuk PFC converter based on variable inductor are analyzed in detail, and the analysis of PF, the voltage of intermediate capacitor, and design considerations are provided. To verify the feasibility of the proposed scheme and compare the characteristics of both the traditional and proposed Cuk PFC converter, a 108W experimental prototype of the proposed converter is built and tested. The experimental results show that the proposed Cuk PFC converter can significantly enhance the PF, decrease the intermediate capacitor voltage, and increase efficiency compared with the traditional Cuk PFC converter.