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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.

The port-controlled Hamiltonian (PCH) system has gained increasing interest in the control and energy community [

By utilizing the energy concept and the internal structural property, several methods have been developed for the controller design of PCH systems [

For power systems, the energy shaping is generally achieved by modifying the energy transfer pattern between the mechanical and the electrical components, which is obtained by injecting damping into the electrical dynamic. The conventional IDA-PBC excitation controller cannot directly reassign the mechanical damping in the swing equation, though the damping in the swing equation is very important for transient stability improvement. In this paper, we propose a novel IDA-PBC excitation controller to enhance the transient stability of power systems by choosing a convenient interconnection matrix and find a solution for the matched partial derivative equation. The proposed excitation controller not only provides a compensation damping into electrical dynamic equation, but also into the mechanical swing equation. Simulation results verify that, compared to the conventional energy-shaping method [

The rest of the paper is organized as follows. In

Consider the following nonlinear system:

Suppose the system can be represented as the following PCH formulation,

If the Hamiltonian function

Generally, for a dissipative Hamiltonian realization of the system in Equation (1), we have following result [

According to Lemma 1, the main procedure of the IDA-PBC methodology can be briefly described as follows:

Fix the desired structure of the interconnection and damping matrix.

Derive a partial differential equation (PDE) parameterized by the chosen matrices whose solutions characterize all the energy functions that can be assigned.

Choose one solution that satisfies the minimum requirement and computer the control.

Consider a single machine infinite bus power system as shown in

the configuration of a single machine infinite bus power system.

The dynamic of the system can be presented as

Let

It can be verified that

Noticing that the largest invariant set

The closed loop system can be written as

It can be seen from the matrix

In the following, we use the IDA-PBC method to design an effective excitation controller to improve the performance of the system. First, assume the desired dissipative Hamiltonian realization of the power system can be formulated as

Let the feedback stabilization controller

Thus we have

From above equations we can see that

Let

In order to guarantee a positive definite

According to Lemma 1, under the desired Hamiltonian realization the stabilization control scheme of the system can be chosen as

To show the effectiveness of the proposed controller, we compare it with the conventional IDA-PBC controller [

Response of the rotor angle under a circuit fault.

During the simulation, a three-phase temporary short-circuit fault is assumed to occur at the transmission line, starting at time

Response of the terminal voltage of generator under a circuit fault.

From the simulation results, it can be seen that, when the fault occurs, the proposed nonlinear stabilization control scheme makes the system responds much faster than the conventional passivity-based controller and PSS+AVR controller . It follows that the proposed controller outperforms the traditional controller in transient stability enhancement of the power system.

The excitation control of a single machine infinite bus power system based on the IDA-PBC method is investigated . We propose a novel excitation controller by choosing the desired interconnection and damping matrix, and solving the PDE to get the corresponding Hamiltonian function. An excitation controller is put forward based on the new Hamiltonian realization system, which not only injects damping into the electronic equation, but also reshapes the mechanical swing equation. Simulation results show that the proposed control scheme can effectively improve the transient stability of the power system.

This work was supported by the National Natural Science Foundation of China (No. 60974005 and 61104022), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20094101120008) and the Science and Technique Research Program of Henan Educational Committee (No. 13A520379).

The authors declare no conflict of interest.