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Specified structure mixed H2=H∞ control-based robust frequency stabilization in a smart grid by plug-in hybrid electric vehicles
(2013-01-16)
Ngamroo, Issarachai
In the future smart grid, the penetration of wind power tends to increase significantly. This may cause the tie-line power and frequency fluctuations in the power grid. On the other hand, the plug-in hybrid electric vehicles (PHEV) are highly expected to be installed in the customer side. The bidirectional power control of PHEV can be applied to stabilize the power and frequency fluctuations. This paper proposes the specified structure mixed H<inf>2</inf>=H<inf>∞</inf> control design of bidirectional power controller of PHEV for robust frequency stabilization of the smart grid with large wind farms. System uncertainties are represented by the multiplicative perturbation model. The structure of power controller is specified as a proportional integral (PI) with single input. The PI parameters optimization problem is formulated based on the enhancement of control performance and robustness against system uncertainties. Without the difficulty of weighting functions selection as in a mixed H<inf>2</inf>=H<inf>∞</inf> control, the PI parameters are automatically tuned by particle swarm optimization. Simulation results confirm that the proposed robust controller is much superior to the conventional controller in terms of control performance and robustness against various uncertainties. © 2013 ICIC International.
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Robust coordinated control of electrolyzer and PSS for stabilization of microgrid based on PID-based mixed H 2/H ∞ control
(2012-09-01)
Ngamroo, Issarachai
In the stand-alone microgrid with hybrid wind, fuel cell (FC) with electrolyzer (EZ) and diesel generations, the intermittent wind power may cause the serious power fluctuation. In addition to the hydrogen production for FC, the EZ can be used to alleviate power fluctuation by an appropriate control of the absorbed power. Nevertheless, the EZ may fail to suppress the power fluctuation due to large disturbances. To enhance the EZ control performance, a power system stabilizer (PSS) which is assumed to be equipped with a diesel generator can be used. This paper proposes the robust coordinated control of EZ and PSS for microgrid stabilization. The structure of power controller of EZ and PSS is a proportional-integral-derivative (PID). To improve the damping performance and robustness of EZ controller and PSS, the PID parameters of both EZ and PSS are simultaneously tuned based on the mixed H <inf>2</inf>/H <inf>∞</inf> control by bee colony optimization. Simulation studies show that the stabilizing performance and robustness of the proposed EZ and PSS are superior to those of the individual device under system uncertainties such as various wind patterns, loading conditions and severe faults. © 2012 Elsevier Ltd.
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PMU-based system identification for wide area robust PSS design in interconnected power systems with wind farm
(2012-01-01)
Ngamroo, Issarachai
It is well known that the penetration of wind power in the smart power grids not only causes the power fluctuation problem, but also results in the system instability. To tackle this problem, a sophisticated design of robust power system stabilizer (PSS) based on system identification using multiple synchronized phasor measurement units (PMUs) is proposed. The small load fluctuation is applied to the system in order to generate the phasor data measured from multiple PMUs which are assumed to be located in the system. Applying the least square method, the phasor data are used to identify the coupled vibration model (CVM) which represents the dominant inter-area oscillation modes. The CVM is used to design the PSS which is a 2nd-order lead-lag compensator. To take system uncertainties such as variation of system parameters etc., in the CVM, the inverse additive perturbation model is applied. Based on an enhancement of the robust stability margin and damping effect, the PSS parameters optimization problem is formulated. The genetic algorithm is used to solve the problem and achieve the PSS parameters. The performance and robustness of the proposed PSS are evaluated in the IEEJ Western Japan 10 machine power system with wind farm in comparison with a conventional PSS. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.
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Simultaneous optimization of SMES coil size and control parameters for robust power system stabilization
(2011-06-01)
Ngamroo, Issarachai
As the coil size is the heart of superconducting magnetic energy storage (SMES), the simultaneous optimization of coil size and control parameters of SMES for robust power system stabilization is proposed. The structure of active and reactive power controllers of SMES is the practical first-order lead/lag compensator. To handle system uncertainties such as various generating and loading conditions, unpredictable network structures etc., the multiplicative uncertainty model is embedded in the system modeling. As a result, the optimization problem of SMES coil size and controller parameters based on the enhancement of system damping and robust stability margin against system uncertainties can be formulated. Solving the problem by a particle swarm optimization, both optimal coil size and controller parameters are obtained simultaneously and automatically. Simulation study in the West Japan six-area interconnected power system with two SMES units confirms the superior robustness and damping performance of the proposed SMES controller with an optimal coil size under various situations in comparison with the conventional SMES controller. © 2011 IEEE.
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Robust controller design of heat pump and plug-in hybrid electric vehicle for frequency control in a smart microgrid based on specified-structure mixed H2/H∞ control technique
(2011-01-01)
Vachirasricirikul, Sitthidet
;
Ngamroo, Issarachai
This paper proposes a new robust controller design of heat pump (HP) and plug-in hybrid electric vehicle (PHEV) for frequency control in a smart microgrid (MG) system with wind farm. The intermittent power generation from wind farm causes severe frequency fluctuation in the MG. To alleviate frequency fluctuation, the smart control of power consumption of HP and the power charging of PHEV in the customer side can be performed. The controller structure of HP and PHEV is a proportional integral derivative (PID) with single input. To enhance the performance and robustness against system uncertainties of the designed controller, the particle swarm optimization based-mixed H<inf>2</inf>/H<inf>∞</inf> control is applied to design the PID controllers of HP and PHEV. Simulation studies confirm the superior robustness and frequency control effect of the proposed HP and PHEV controllers in comparison to the conventional controller. © 2011.
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Coordinated SVC and AVR for robust voltage control in a hybrid wind-diesel system
(2010-12-01)
Vachirasricirikul, Sitthidet
;
Ngamroo, Issarachai
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Kaitwanidvilai, Somyot
This paper proposes a robust control of voltage fluctuation due to the variation of reactive loads in an isolated wind-diesel hybrid power system using Static Var Compensator (SVC) and Automatic Voltage Regulator (AVR). The structure of the voltage controller of SVC and AVR is the proportional integral (PI) controller with single input. In the system modeling, a normalized coprime factorization is applied to represent possible unstructured uncertainties in the power system such as variation of system parameters and generating and loading conditions. Based on the H<inf>∞</inf> loop shaping, the performance and robust stability conditions of the control system are formulated as the optimization problem. The genetic algorithm is applied to solve an optimization problem and to achieve PI control parameters of SVC and AVR simultaneously. Simulation studies show the control effect and robustness of the proposed coordinated SVC and AVR. © 2010 Elsevier Ltd. All rights reserved.
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Robust frequency control in the smart microgrid by heat pump and plug-in hybrid electric vehicle
(2010-12-01)
Rattanapornchai, Chalotorn
;
Ngamroo, Issarachai
;
Vachirasricirikul, Sitthidet
This paper proposes a new controller design of heat pumps (HP) and plug-in hybrid electric vehicles (PHEV) for robust frequency control in a smart microgrid (MG) system with wind farm. The system frequency can be controlled by the smart power charging of HP and PHEV. The structure of power charge controller is a proportional integral derivative (PID) with single input. System uncertainties are modeled by the multiplicative uncertainty. By taking the robust stability margin into account, the particle swarm optimization (PSO) is applied to optimize the PID controller parameters of HP and PHEV concurrently based on specified-structure mixed H<inf>2</inf>/H<inf>∞</inf> control approach. Simulation results confirm the superior robustness and performance of the proposed control.
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Design of robust centralized PSS based on WAMS considering system and signal transmission delay uncertainties
(2010-12-01)
Saejia, Mongkol
;
Ngamroo, Issarachai
It is well known that the time delay due to the wide-area phasor measurement unit (PMU) as well as various system operations may deteriorate the stabilizing effect of wide area monitoring system (WAMS). To overcome this problem, this paper proposes the design of robust centralized power system stabilizer (PSS) for wide area stabilization taking uncertainties due to system operations and signal transmission delay into account. The uncertainties due to system operations and time delay are represented by the inverse input and output multiplicative model. The structure of centralized PSS controller is the practical second order lead/lag compensator. To automatically tune the control parameter, the optimization problem based on the enhancement of damping performance and system robust stability margin is achieved by particle swarm optimization. Simulation studies in the two-area four-machine interconnected power system confirm that the proposed robust PSS centralized controller is superior to the conventional PPS in terms of robustness against system and time delay uncertainties.
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Wide area robust TCSC controller design considering communication delay uncertainty
(2010-07-30)
Saejia, Mongkol
;
Ngamroo, Issarachai
This paper focuses on a robust fixed structure controller design of thyristor controlled series capacitor (TCSC) for wide area stabilization taking uncertainty due to communication delay into account. Since the control signals measured from phasor measurement units (PMU) are global signals, the communication delay is an inevitable problem. When these PMU signals are used as the input of TCSC, the stabilization effect of TCSC may be deteriorated. To tackle this problem, an uncertainty due to time delay is represented by the inverse input multiplicative model. The structure of controller is the practical lead/lag compensator with single input. To enhance the robustness, the controller parameters are optimized by genetic algorithm (GA). Simulation studies in the two-area four-machine interconnected power system confirm the robustness of the proposed TCSC controller against the delay uncertainty.
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Robust SMES controller design based on inverse additive perturbation for stabilization of interconnected power systems with wind farms
(2010-03-01)
Ngamroo, Issarachai
This paper proposes a robust controller design of Superconducting Magnetic Energy Storage (SMES) for stabilization of tie-line power oscillation in the interconnected power systems with wind farms. The inverse additive perturbation model is applied to represent system uncertainties such as several generating and loading conditions, variation of system parameters, wind power fluctuations, etc. The structure of active and reactive power controllers of SMES is the first-order lead-lag compensator. To tune the controller parameters, the optimization problem is formulated based on the enhancement of additive stability margin. The genetic algorithm is used to solve the problem and achieve the controller parameters. Simulation studies in the two-area four-machine interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions. © 2009 Elsevier Ltd. All rights reserved.

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