Chunwen Li

Adaptive H ∞ excitation control of multimachine power systems via the Hamiltonian function method

Using the Hamiltonian function method, this paper investigates the adaptive H ∞ excitation control of multimachine power systems with disturbances and parameter perturbations. A key step in applying the Hamiltonian function method to the multimachine system is to express the system as a dissipative Hamiltonian system, i.e. to complete dissipative Hamiltonian realization (DHR). By using pre-feedback technique, this paper expresses the multimachine power system as a dissipative Hamiltonian system. Then, the stability analysis of the achieved dissipative Hamiltonian system is proceeded. Finally, based on the achieved DHR form, the adaptive H ∞ excitation control of the multimachine power system is investigated and a decentralized simple excitation control strategy is obtained. Simulations on a six-machine system show that the adaptive H ∞ excitation control strategy proposed in the paper is more effective than some other control schemes.

Energy-Based

Using an energy-based method, this paper investigates the L 2 disturbance attenuation excitation control of multimachine power system connected with constant power loads. First, a general result is presented for the L 2 disturbance attenuation control of nonlinear differential algebraic systems with dissipative Hamiltonian realization. Then, pre-feedback is employed to transform the power system into a dissipative Hamiltonian form. Based on this, a decentralized L 2 excitation control scheme is proposed to improve the transient stability of the system. Simulation results demonstrate the effectiveness of the controller.

L_2

This paper investigates some basic problems of the dissipative Hamiltonian realization (DHR) of nonlinear differential algebraic systems (NDAS). First, based on a novel DHR formulation which can present the internal structure properties of NDAS, the stability of the Hamiltonian realizable autonomous NDAS is analyzed. Then, the dissipation of series, parallel and feedback combination of NDAS is discussed. These results will facilitate the analysis and synthesis of complex NDAS.

Disturbance Attenuation Excitation Control of Differential Algebraic Power Systems

Using the Hamiltonian function method, we investigate the excitation control of power systems presented by nonlinear differential algebraic equations. First, a novel Hamiltonian realization structure for nonlinear differential algebraic systems is applied to the power system. Then we propose a decentralized nonlinear excitation control scheme and analyze the stability of the closed loop system. This strategy takes advantage of the intrinsic properties including especially the internal power balance of the differential algebraic power system model. Simulation illustrates the effectiveness of the control strategy.

On the Dissipative Hamiltonian Realization of Nonlinear Differential Algebraic Systems

Passivity-based control is widely used in electronic circuit systems because it can utilize their internal structures to facilitate the controller design. In this paper, we first propose a dissipative Hamiltonian realization of power systems and discuss the disadvantages of the traditional passivity-based excitation controller. Then, a novel excitation controller is put forward to reassign the interconnection and dissipative matrix, and the corresponding Hamiltonian function. Simulation results verify that the proposed controller can effectively improve the transient stability of the power system.

Energy-based Decentralized Excitation Control of Nonlinear Differential Algebraic Power Systems

Port-controlled Hamiltonian system method is very useful in the performance enhancement control of power systems, of which the key step is to model the power system as a dissipative Hamiltonian system, i.e., to complete the dissipative Hamiltonian realization (DHR). This paper proposes a DHR for multi-machine multi-load power systems based on a novel DHR structure for nonlinear differential algebraic systems, with which we derive a sufficient condition for the existence and construction of DHRs with constant structure matrices. An example shows that the proposed DHR can facilitate the excitation controller design of power systems.

Passivity-Based Nonlinear Excitation Control of Power Systems with Structure Matrix Reassignment

Using an energy-based Hamiltonian function method, this paper investigates the robust excitation control of multi-machine multi-load power systems described by a set of uncertain differential algebraic equations. First, we complete the dissipative Hamiltonian realization of the power system and adjust its operating point by the means of pre-feedback control. Then, based on the obtained Hamiltonian realization, we discuss the robust excitation control of the power system and put forward an H ∞ excitation control strategy. Simulation results demonstrate the effectiveness of the control scheme.

Dissipative Hamiltonian Realization of Multi-machine Multi-load Power Systems

Using the Hamiltonian function method, this paper investigates the coordinated control of generator and static var compensator (SVC) in power systems with nonlinear loads. First, via a proper variable transformation and pre-feedback control, the dissipative Hamiltonian realization of the power system is completed. The operating point is set to a desired value simultaneously. Then, based on the dissipative Hamiltonian realization, an energy-based coordinated controller is constructed. The proposed controller can effectively utilize the internal structure of the system and is simple in form. Simulation results indicate that the coordinated controller can improve the transient stability of the system.

Saturated Excitation Control of Multi-machine Multi-load Power Systems Using Hamiltonian Function Method

Interconnection and damping assignment passivity-based control (IDA-PBC) is a technique that regulates the behavior of nonlinear systems by assigning a desired port-controlled Hamiltonian structure. In this paper, based on the original dissipative Hamiltonian realization of a single-machine-infinite-bus power system, we design a controller to re-formulate the interconnection matrix and stabilize the power system. Simulation result verifies the effectiveness of the proposed control scheme.

Energy-based coordinated control of generator and static var compensator in power systems with nonlinear loads

The asymptotic stable observer design for a class of nonlinear descriptor system is investigated in this paper. First, we further extend the LaSalles invariance principle of index one nonlinear descriptor systems and put forward a sufficient condition for the asymptotically stability of the system. Then, we discuss the observer design of the nonlinear descriptor systems satisfying the Lipschitz condition. Some sufficient conditions are proposed for the existence of asymptotically stable observer. An algorithm is put forward for the construction of the observer gain matrix.