Input Current Sensor Research Articles

Detection and mitigation of false data injection attack in DC–DC synchronous boost converter: A real‐time implementation using shallow neural network model

AbstractWith implementing cyber‐physical systems, modern power systems are at continuous risk of cyber‐attacks. Sensor data that is communicated through the communication links is the most vulnerable entity. The attacker breaches the confidentiality of the data and affects the controller's performance, destabilizing the system. This article proposes a neural network‐based cyber‐attack detection and mitigation scheme to detect and mitigate false data injection attacks on the sensors. Neural networks are used to predict duty; a combination of a data sampler and binary attack detector detects the presence of an attack. Attack mitigation is performed in the final step by analysing the outputs of prediction and detection networks. The designed control scheme is demonstrated at the DC–DC converter level by considering the synchronous boost converter as a plant with an input voltage sensor, output voltage sensor, input current sensor, and output current sensor. The shallow neural network model is trained with appropriate hyperparameters to obtain a root mean square error of 0.003. The control scheme is designed and implemented in MATLAB Simulink platform and realized in real‐time hardware setup by deploying the neural network into the microcontroller and its results are explored.

Parameter-Variation-Tolerant Robust Current Sensorless Control of a Single-Phase Boost PFC

With the objective to eliminate the input current sensor in a totem-pole boost power factor corrector (PFC) for its low-cost design, a novel discretized sampling-based robust control scheme is proposed in this work. The proposed control methodology proves to be beneficial due to its ease of implementation and its ability to support high-frequency operation, while being able to eliminate one sensor and, thus, enhancing reliability and cost-effectiveness. In addition, detailed closed-loop stability analysis is carried out for the controller in discrete domain to ascertain brisk dynamic operation when subjected to sudden load fluctuations. To establish the robustness of the proposed control scheme, a detailed sensitivity analysis of the closed-loop performance metrics with respect to undesired changes and inherent uncertainty in system parameters is presented in this article. A comparison with the state-of-the-art (SOA) methods is provided, and conclusive results in terms of better dynamic performance are also established. To verify and elaborate on the specifics of the proposed scheme, a detailed simulation study is conducted, and the results show 25% reduction in response time as compared to SOA approaches. A 500-W boost PFC prototype is developed and tested with the proposed control scheme to evaluate and benchmark the system steady-state and dynamic performance. A total harmonic distortion of 1.68% is obtained at the rated load with a resultant power factor of 0.998 (lag), which proves the effectiveness and superiority of the proposed control scheme.

DC motor fault detection and isolation scheme with the use of directional residual set

The subject of research is presented as online-estimation of characteristics of DC motors under various loads. The paper is devoted to a modern approach to solve the problem of detecting DC motor failures. Proposed detection method is based on the set of full state Luenberger observers. Isolation scheme uses directional residual set and relationships between fault direction and residual vector. The procedure of synthesizing the fault detection and isolation algorithm for DC motor is designed. This scheme performance is proved with computer modeling of typical DC motor RK 370CA with faults caused by unaccounted force momentum acting on rotor, input voltage disturbance, velocity and current sensors failures. The algorithm correctly defines motor state (fault presence or absence) and also properly isolates fault cause. Proposed method advantage is compared to other solutions based on hardware and timing redundancy, identification and observers lies in the opportunity to detect and isolate faults of input and output signals with trivial synthesis and absence of the need to expand system hardware. Proposed method is applicable to any second order system, and also there is a possibility to use it for higher order systems with the corresponding changing of the equation systems solving for observer synthesis. This algorithm allows realizing online fault isolation and does not require additional measuring which promotes decrease of diagnostic costs, repair and serving time saving, modern accident detection. The results can be applied to DC motor control to increase reliability and to develop DC motor control systems.

Hot-Swappable Grid-Connected Multilevel Converter for Battery Energy Storage System

The objective of this brief is to propose a hot-swappable grid-connected multilevel converter (HGM-converter) for the battery energy storage system (BESS). The proposed HGM-converter is composed of series-connected bi-directional H-bridge sub-converters and a LCL filter. Advantages of the proposed HGM-converter include: hot-swappable capability, single-stage power conversion, low dc-bus voltage, and individual power control for each battery module. Therefore, the equalization, lifetime extension, and capacity flexibility of the BESS can be achieved. Based on the equivalent model, the power flow of the battery module can be estimated without the need of input current sensor. Also, with the interleaved operation between the sub-converters, the current ripple of the output inductor can be reduced too. The computer simulations and hardware experimental results are shown to verify the performance of the proposed HGM-converter.

Bidirectional Single-Stage Grid-Connected Inverter for a Battery Energy Storage System

The objective of this paper is to propose a bidirectional single-stage grid-connected inverter (BSG-inverter) for the battery energy storage system. The proposed BSG-inverter is composed of multiple bidirectional buck–boost type dc–dc converters (BBCs) and a dc–ac unfolder. Advantages of the proposed BSG-inverter include: single-stage power conversion, low battery and dc-bus voltages, pulsating charging/discharging currents, and individual power control for each battery module. Therefore, the equalization, lifetime extension, and capacity flexibility of the battery energy storage system can be achieved. Based on the developed equations, the power flow of the battery system can be controlled without the need of input current sensor. Also, with the interleaved operation between BBCs, the current ripple of the output inductor can be reduced too. The computer simulations and hardware experimental results are shown to verify the performance of the proposed BSG-inverter.

Modeling and Controller Design of PV Micro Inverter without Using Electrolytic Capacitors and Input Current Sensors

This paper outlines the modeling and controller design of a novel two-stage photovoltaic (PV) micro inverter (MI) that eliminates the need for an electrolytic capacitor (E-cap) and input current sensor. The proposed MI uses an active-clamped current-fed push-pull DC-DC converter, cascaded with a full-bridge inverter. Three strategies are proposed to cope with the inherent limitations of a two-stage PV MI: (i) high-speed DC bus voltage regulation using an integrator to deal with the 2nd harmonic voltage ripples found in single-phase systems; (ii) inclusion of a small film capacitor in the DC bus to achieve ripple-free PV voltage; (iii) improved incremental conductance (INC) maximum power point tracking (MPPT) without the need for current sensing by the PV module. Simulation and experimental results demonstrate the efficacy of the proposed system.

A fuzzy maximum power point tracking method for photovoltaic systems using a single input current sensor

Maximum power point tracking (MPPT) is one of the major issues in photovoltaic (PV) systems and plays a vital role in optimal utilization of these systems for practical applications. In this paper, we propose a new MPPT method that requires only one current sensor in PV panel side and uses a fuzzy controller to generate proper duty cycle for the DC–DC converter in a PV system. The input current sensor‐based fuzzy MPPT method (ICSF) exhibits proper operation both under steady state and dynamic tests and also performs well in case of severe environmental variations. The proposed method has been simulated in the MATLAB/Simulink workspace and compared with some major MPPT methods. The results reveal that the proposed method behaves well in various conditions. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

교류측 전압 및 전류 센서가 없는 3상 Z-소스 PWM 정류기의 퍼지-PI 제어

In this paper, we proposes the AC input voltage and current sensorless control scheme to control the input power factor and DC output voltage of the three-phase Z-source PWM rectifier. For DC-link voltage control which is sensitive to the system parameters of the PWM rectifier, fuzzy-PI controller is used. Because the AC input voltage and current are estimated using only the DC-link voltage and current, AC input voltage and current sensors are not required. In addition, the unity input power factor and DC output voltage can be controlled. The phase-angle of the detected AC input voltage and estimated voltage, the response characteristics of the DC output voltage according to the DC voltage references, the FFT results of the estimated voltage and current, efficiency, and the response characteristics of the conventional PI controller and fuzzy-PI controller are verified by PSIM simulation.

AC voltage and current sensorless control of three-phase PWM rectifiers

In this paper, a novel control scheme of three-phase PWM rectifiers eliminating both the AC input voltage and current sensors is proposed. The phase angle and the magnitude of the source voltage are estimated by controlling the deviation between the rectifier current and its model current to be zero. The input currents can be reconstructed from switching states of the PWM rectifier and the measured DC link currents. To eliminate the calculation time delay effect of the microprocessor, the currents ahead one sampling period are estimated by a state observer and then are used for feedback control. The proposed control scheme reduces the system cost and improves its reliability. The feasibility of the proposed AC sensorless technique for three-phase PWM rectifiers has been verified through experiments using a high performance DSP chip.

Mixed-mode operation of boost switch-mode rectifier for wide range of load variations

A mixed-mode input current sensorless predictive current control at constant but two different switching frequencies for a single-phase boost type switch-mode rectifier (SMR) with single switch topology is proposed. The SMR operates in continuous input current mode (CCM) or in discontinuous input current mode (DCM) depending upon the load. This load dependent operating mode selection avoids the operation of the SMR in the dual mode, where the input current harmonic distortion is maximum. The closed loop output voltage regulation is achieved without the need of an input current sensor. The control scheme is optimized to result in an economic size of the boost inductor along with the compliance of IEC 1000-3-2 harmonic limits for input current.

A fuzzy-controlled active front-end rectifier with current harmonic filtering characteristics and minimum sensing variables

A control strategy which allows conventional voltage-source current-controlled (VSCC) pulsewidth modulation (PWM) rectifiers to work simultaneously as active power filters is presented. The proposed control strategy also allows compensating the system power factor and compensating unbalanced loads. The measurement and/or calculation of the harmonics and reactive power are not required, making the proposed control scheme very simple. The active front-end rectifier acts directly on the mains line currents, forcing them to be sinusoidal and in phase with the mains voltage supply. To improve the dynamic of the system, the amplitude of the current is controlled by a fuzzy system, which adjusts the DC-link voltage of the PWM rectifier. The strategy is based on connecting all the polluting loads between the PWM rectifier and their input current sensors. The main advantages of this approach are the following: (1) there is no need to install a specially dedicated active power filter; (2) it also works simultaneously as a power factor compensator; and (3) no special and complicated calculations are required for harmonic elimination. The viability of the proposed active front-end rectifier is proved by simulation and with experimental results obtained from a 2 kVA PWM prototype.

A novel load current control method for a leading power factor voltage source PWM rectifier

A novel PWM voltage source rectifier, controlled by the load DC current instead of the DC voltage, has been developed. Its main characteristics are: (a) there is neither input current sensors nor DC voltage sensor; (b) it works with an unchangeable and predefined PWM pattern; (c) it presents a very strong stability; (d) its stability does not depend on the size of the DC capacitor; (e) it can work at leading power factor for all load conditions; and (f) it can also work with zero regulation for all load conditions. Digital simulations, analyses, and experiments confirm all these characteristics of the control method. >