Multivariable integral linear quadratic Gaussian robust control of islanded microgrid to mitigate voltage oscillation for improving transient response

Sarker, Subrata; Badal, Faisal R.; Das, Purnima; Das, Sajal K.

doi:10.1002/asjc.2215

Cited by 25 publications

(14 citation statements)

References 28 publications

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“…Here, the inverter is represented by power converter block where terminal P and Q are connected to the grid side through filter inductors. The leakage current is thus the function of grid voltage(V G ), parasitic capacitance (C P ), V PN , V QN and filter inductances and capacitance, where, V PN is the voltage between the points P and N, and V QN is the voltage between the points Q and N. Thus, The differential mode (DM) voltage, V PQ can be represented as [43], (11) and the CM voltage is,…”

Section: Leakage Current Problem Analysis Of Transformerless Invementioning

confidence: 99%

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A Blended Improved H5 Topology With ILQG Controller to Augment the Performance of Microgrid System for Grid-Connected Operations

et al. 2020

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The development of the world demands on the progress of electricity operation and quality enhancement. Microgrid (MG) is a solution that manages the additional need of electricity. The MG generates electricity mostly from renewable energy sources, e.g. solar, wind and hydro. Most renewable energy sources require energy storage system as they are highly unpredictable in nature. An inverter is needed to convert that stored DC power to AC. The presence of a capacitor within the grid provides a galvanic connection that varies the common mode (CM) voltage of the inverter. Thus, the leakage current as well as the total harmonic distortion (THD) of the grid voltage and current increases. The increase of the leakage current hampers the safe operation of the MG. Now-a-days transformerless inverter is gaining more attention because of high efficiency, low cost, less weight and the capability of eliminating the high frequency component from the inverter CM voltage. In addition, a controller inclusion with a transformerless inverter can maintain a near-seamless performance. This paper proposes a blended technique of an improved H5 topology with an Integral Linear Quadratic Gaussian (ILQG) controller for grid-connected MG operations, that reduces the inverter leakage current by keeping the CM voltage constant. Thus it has the capability to reduce the THD of voltage and current. A comparative analysis has been carried out between this technique and existing topologies with different modulation techniques that helps to find out the most optimum inverter package to eliminate the leakage current and reduce the THD of grid voltage and grid current to almost zero. INDEX TERMS Microgrid, transformerless inverter, improved H5 inverter, ILQG controller.

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Section: Leakage Current Problem Analysis Of Transformerless Invementioning

confidence: 99%

“…During the large disturbance, the MG is disconnected from the main grid through PCC and allow to operate independently. The VSI is the key element that converts the DC power which is stored in the energy storage system to AC whose operation is quite challenging [10], [11]. These inverters are built with or without transformer.…”

Section: Introductionmentioning

confidence: 99%

A Blended Improved H5 Topology With ILQG Controller to Augment the Performance of Microgrid System for Grid-Connected Operations

et al. 2020

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“…Linear quadratic regulator (LQR), designed by linearization technique, is an approach to achieve accurate operation of the microgrid system [30], [31]. The LQR is developed using a mean value theorem.…”

Section: B Literature Reviewmentioning

confidence: 99%

A Novel Blended State Estimated Adaptive Controller for Voltage and Current Control of Microgrid Against Unknown Noise

et al. 2019

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In this study, a novel blended state estimated adaptive controller is designed for voltage and current control of microgrid against unknown noise. The core feature of the microgrid (MG) is its ability to integrate more than one distributed energy resource into the main grid. The state of a microgrid may deteriorate due to many reasons, for example malicious cyber-attacks, disturbances, packet losses, etc. Therefore, it is necessary to achieve the true state of the system to enhance the control requirement and automation of the microgrid. To achieve the true state of a microgrid, this study proposes the use of an algorithm based on the unscented kalman filter (UKF). The proposed state estimator technique is developed using an unscented-transformation and sigma-points measurement technique capable of minimizing the mean and covariance of a nonlinear cost function to estimate the true state of a single-phase, three-phase single-source and three-phase multi-source microgrid system. The advantage of the proposed estimator over using extended kalman filter (EKF) is investigated in simulations. The results demonstrate that the use of the UKF estimator produces a superior estimation of the system compared with the use of the EKF. An adaptive PID controller is also developed and used in system conjunction with the estimator to regulate its voltage and current against the number of loads. Deviation in load parameters hamper the function of the MG system. The performance of the developed controller is also evaluated against number of loads. Results indicate the controller provides a more stable and high-tracking performance with the inclusion of the UKF in the system. INDEX TERMS Microgrid, model reference adaptive control, state estimation, unscented kalman filter, voltage and current control.

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“…The frequency counter gives the accurate line frequency value of 50.41 Hz as shown in Fig. 12 and the phase difference between voltage and current is 53.716 • obtained from (4). After collecting the instrumental data and finishing some calculations, the system obtains some parameters, as shown in Table 2.…”

Section: Ac Power Measured By the Measuring Devicementioning

confidence: 99%

“…The power factor directly relates to the system efficiency and performance. A large amount of load current results in lower voltage regulation of the system and provides a large joule loss in the power lines [4,5]. The lower voltage level generates heat in the motor windings that reduces the lifetime, reliability and performance of the machine [6,7].…”

Section: Introductionmentioning

confidence: 99%

A novel fractional order power factor measurement

et al. 2019

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This paper presents the design and experimental implementation of a smart power factor metering system to measure the fractional order power factor of a load. The variation of grid frequency or power factor (PF) increases the utility charges. The proposed design provides an accurate PF measurement by using a real-time AC power triangle. The system is designed by proposing a novel embedded system based controller that enables reading the main-line frequency, load voltage, current and their phase differences. A converter is designed first to transform the high voltage and current to the controller. The converter consists of a potential transformer, a current transformer, high differential strobe terminal based comparator and a logic gate that detects the phase delay between the load voltages and currents. A set of parallel capacitors are interconnected with the load terminal for improved PF measurement. The improved power factor confirms the saving of the utility charges for inductive loads. The simulation and experimental results are demonstrated to validate the effectiveness of proposed metering system.

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Multivariable integral linear quadratic Gaussian robust control of islanded microgrid to mitigate voltage oscillation for improving transient response

Cited by 25 publications

References 28 publications

A Blended Improved H5 Topology With ILQG Controller to Augment the Performance of Microgrid System for Grid-Connected Operations

A Blended Improved H5 Topology With ILQG Controller to Augment the Performance of Microgrid System for Grid-Connected Operations

A Novel Blended State Estimated Adaptive Controller for Voltage and Current Control of Microgrid Against Unknown Noise

A novel fractional order power factor measurement

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