CN114142471B - A Reconfiguration Method of Ship Integrated Power System Considering Communication Failure - Google Patents

Abstract

The invention relates to a reconstruction method of a ship comprehensive power system in a partially observable state, which comprises the following steps: step 1, if an event is observed to occur, performing step 2, otherwise, waiting for an observable event; step 2, performing state estimation; step 3, judging whether the system can perform fault-tolerant control; step 4: judging whether the system fails, if so, performing step 5, otherwise, returning to step 1; step 5: judging whether the system can perform recovery operation or not, if so, triggering a corresponding event sequence by the controller after the staff agrees to perform recovery operation so that the system enters a recoverable state to wait for recovery event occurrence, otherwise, sending a signal that recovery operation cannot be performed; step 6: and if the recovery operation cannot be performed currently, performing reconstruction operation on the system with the aim of recovering the maximum load power, and waiting for the recovery operation. The invention can estimate the system state under partial observability, increase the reconstruction application scene and improve the coping capability of the system under faults.

Description

A Reconfiguration Method of Ship Integrated Power System Considering Communication Failure

technical field

The invention relates to the technical field of ship integrated power systems, in particular to a reconfiguration method for improving the vitality of ship comprehensive power systems, especially a reconfiguration method for ship comprehensive power systems considering communication failures.

Background technique

Different from the land power system, the ship integrated power system is a highly integrated system, which is equivalent to a small island microgrid, and has the characteristics of small capacity and harsh working environment. Compared with land power systems, ship integrated power systems are more fragile and prone to failure due to their electrical and physical closure, limited power generation capacity, and complex operating conditions. When a ship is operating at sea, it is isolated and helpless in a harsh environment. When equipment failure, combat damage, improper operation of managers and other factors damage the communication system and other facilities, the comprehensive power system of the ship will fail or run abnormally. In some cases, the state of some electrical equipment in the system is not appreciable, and the system cannot be clear about the current state. If it is not handled properly, it will lead to power supply interruption or grid collapse, which greatly threatens the safety and reliability of the system. , may result in shipwreck and death, so a reconstruction strategy under partial observability is needed to restore the performance of the power supply guarantee system.

However, there is currently no research on the reconfiguration of the ship's integrated power system under partial observability, and with the increase of the system structure and complexity, the status feedback of the system equipment and the communication between the equipment become more and more important, so the problem of communication interruption is in the reconfiguration It is one of the problems that cannot be ignored. However, the reconfiguration of the system due to communication interruption due to faults and the unsatisfactory state of electrical equipment has not been fully considered at present.

Contents of the invention

According to the characteristics of the ship's integrated power system, the present invention provides a method based on state estimation for the reconstruction of the ship's integrated power system due to internal or external causes of cable failures and communication network failures, which cause the entire ship's power system to be in a partially observable state. A reconfiguration strategy of ship integrated power system considering partial observability is proposed.

In order to achieve the above object, the present invention is achieved through the following technical solutions:

The present invention is a method for reconfiguring a ship's integrated power system in a partially observable state, specifically comprising the following steps:

Step 1: If an event is observed, go to step 2, otherwise wait for a considerable event;

Step 2: Perform state estimation. After state estimation in step 2, it is necessary to check whether there is an uncontrollable event in this state that makes the system enter an illegal state. If so, disable the uncontrollable and enter the illegal state. The last controllable event.

Step 3: Determine whether the system can perform fault-tolerant control. If fault-tolerant control can be performed, the controller disables the corresponding event, otherwise it sends a signal that fault-tolerant control is not possible;

Step 4: Determine whether the system is faulty, if there is a fault, go to step 5, otherwise return to step 1;

Step 5: Determine whether the system can perform the recovery operation. If the recovery operation is possible, when the staff agrees to perform the recovery operation, the controller triggers the corresponding event sequence to make the system enter the recoverable state and wait for the recovery event to occur. Otherwise, the recovery operation cannot be performed. signal of;

Step 6: If the restoration operation is currently not possible, perform the reconstruction operation on the system with the goal of restoring the maximum load power, and wait for the restoration operation.

A further improvement of the present invention is that the state estimation specifically includes the following steps:

Step 2-1: According to the current state of the system, calculate the state of the system after the events observed at this time;

Step 2-2: Calculate the state of the system after all unobservable events occur when the system is in the state obtained in step 1;

Step 2-3: If the unobservable range does not exist, set the controller to empty, otherwise calculate and disable events in the controller;

Steps 2-4: Output state estimates and disabled events in the state estimate-based controller.

Beneficial effects of the present invention:

1. The present invention can effectively calculate the current state of the system by using the state estimation method of the ship's integrated power system, making the system state more clear;

2. Compared with other reconfiguration methods, the fault-tolerant control method of the ship's integrated power system adopted in the present invention can effectively improve the operating efficiency of the system under fault conditions and improve the system's ability to cope with faults.

3. Compared with other reconfiguration methods, the present invention considers the reconfiguration of the ship's integrated power system under partial observability, can minimize the impact of communication problems on the system, and at the same time improve the vitality of the system.

Description of drawings

Fig. 1 is a flow chart of the reconfiguration of the ship's integrated power system under partial observation in the present invention.

Fig. 2 is a structure diagram of the hybrid system of the present invention.

Fig. 3 is a flow chart of state estimation in the present invention.

Fig. 4 is a structural diagram of the integrated power system of a ship according to the present invention.

Fig. 5 is a diagram of simulation results of the present invention.

Detailed ways

Embodiments of the present invention will be disclosed in the following diagrams. For the sake of clarity, many practical details will be described together in the following description. It should be understood, however, that these practical details should not be used to limit the invention. That is, in some embodiments of the invention, these practical details are not necessary.

1. Hybrid model of ship integrated power system

The invention adopts the hybrid automaton to model the comprehensive power system of the ship, that is, the automaton model can be extended by embedding the differential equation into the automaton model. The present invention adopts the hybrid system structure as shown in Fig. 2, and divides the system into three parts: discrete controller, interface and continuous controlled system. Among them, the discrete controller is described by an automaton, and its behavior is controlled by discrete inputs and discrete events at the interface; the interface is composed of an event generator and a control behavior generator, which is a bridge connecting the discrete dynamic system and the continuous variable dynamic system. information exchange; a continuously controlled system is described by differential equations, whose behavior is affected by continuous inputs and continuous disturbances. In this way, the continuous variable dynamic system and the discrete event dynamic system can be combined to form a hybrid system, and the two systems can influence and interact with each other, which is consistent with the joint influence of continuous dynamic and discrete events when the ship's integrated power system is reconfigured.

The integrated power system of a ship can be represented by a hybrid automaton H:

H=(Q, X, U, Init, f, ∑, EG, T, R) (1)

In formula (1), Q represents the set of all discrete states; Represents a collection of continuous states in a discrete state; Q∪X represents a state space, and Q is a finite set;/> is the set of continuous control inputs; /> Represents the set of initial conditions; f: Q×X×U→X is used to describe the evolution law (differential equations) in the continuous state of q∈Q. ∑＝∑ _c ∪∑ _uc is a set of discrete events, ∑ _c represents a controllable event set, ∑ _uc is an uncontrollable event set; EG is an event generator function; T: ∑×Q→2 ^Q represents a discrete state transition relationship; R : Q×X×U→2 ^X×U is the reset relation, and also represents the control behavior generator function.

2. State estimation under partial observability

When the ship's integrated power system is hit or fails due to its own reasons, in order to ensure system performance, it needs to be reconfigured to maintain a safe state or have a chance to return to a normal structure in a fault state. The former needs fault-tolerant control, while the latter needs to analyze the reconfigurability of the system. By judging whether the system can trigger an event, it can return to the normal state. Finally, by controlling the language sequence of the hybrid automaton, the system can enter the recovery state. Wait for the recovery command after system troubleshooting.

When a fault occurs, the system enters the fault structure H _j from the normal operation structure H _i , and the initial state set Q _{0, j} of the fault structure H _j is defined as:

Define all uncontrollably entered illegal state set Q _il,j state set as:

Then the fault-tolerant control is: if and only if When , the system can perform fault-tolerant control, and its control strategy is:

Then when the above conditions are met, the controller can make the system never enter the illegal state.

Define all the state sets Q _{re, j} that can return to the normal operation structure after entering:

When the system satisfies the fault-tolerant control condition, when When , the system is reconfigurable, and there exists a controller Φ(q) that makes it possible for the system to return to a normal state.

Due to the occurrence of unobservable events due to faults, it is necessary to estimate the state of the system according to the observable event sequence to judge the current state of the system, and perform fault-tolerant control and reconstruction operations based on the obtained state estimation.

When a considerable event occurs, it is necessary to first calculate the state set that the system may directly reach, expressed by the reachable range OR(·):

In formula (20), is the previous state estimate of the current state estimate; σ∈∑ _{o, exd} is an observable event, then the state pre-estimated value is />

final calculation and /> where /> is the unobservable range of x(j) relative to a set of disabled events is the set of states that the system can reach from x(j) through some undisabled unobservable events, defined as follows:

In summary, through the observable events that occur in the system, the state of the system can be estimated, as shown in Figure 3, which specifically includes the following steps:

Step 2-1: According to the current state of the system, calculate the state of the system after the events observed at this time;

Step 2-2: Calculate the state of the system after all unobservable events occur when the system is in the state obtained in step 1;

Step 2-3: If the unobservable range does not exist, set the controller to empty, otherwise calculate and disable events in the controller;

Steps 2-4: Output state estimates and disabled events in the state estimate-based controller.

After state estimation in step 2, it is necessary to check whether there is an uncontrollable event in this state that causes the system to enter an illegal state, and if so, disable the last controllable event in the prefix symbol string of uncontrollable entry into an illegal state.

If it is judged according to the state estimation that the current state may cause the system to enter an illegal state, the fault-tolerant control in the previous section will be adopted, and the disabled can enter Set controllable events to prevent the system from entering an illegal state, otherwise take no action.

When all elements in the state estimation of the system are recoverable, the recovery event can be triggered to return the system to the normal structure. Combined with the content of the previous section, then the recoverable condition under partial observability is:

According to the above analysis, as shown in Figure 1, a reconstruction strategy based on state estimation specifically includes the following steps:

Step 1: If an event is observed, go to step 2, otherwise wait for a considerable event;

Step 2: Do State Estimation

Step 3: Determine whether the system can perform fault-tolerant control. If fault-tolerant control can be performed, the controller disables the corresponding event, otherwise it sends a signal that fault-tolerant control is not possible;

Step 4: Determine whether the system is faulty, if there is a fault, go to step 5, otherwise return to step 1;

Step 5: Determine whether the system can perform the recovery operation. If the recovery operation is possible, when the staff agrees to perform the recovery operation, the controller triggers the corresponding event sequence to make the system enter the recoverable state and wait for the recovery event to occur. Otherwise, the recovery operation cannot be performed. signal of;

Step 6: If the restoration operation is currently not possible, perform the reconstruction operation on the system with the goal of restoring the maximum load power, and wait for the restoration operation.

3. Calculation results

The invention performs partially observable reconfiguration simulation on the annular ship comprehensive power system to demonstrate the above-mentioned strategy reconfiguration process. The simplified structure of the ship's integrated power system is shown in Figure 4. The system consists of three generators, port side busbar, starboard busbar, etc. The power load includes propulsion system, communication system, daily load, etc., and it is divided into upper The three types of loads mentioned in the article assume that the generator power is 36MW, the important load power is 36MW, the secondary load is 2MW, and the unimportant load is 1MW. SWj represents the switching device (where j=1,2,...,24), using 1- 4 represents each load status, double-terminal power supply equipment 1 represents no power supply, 2 represents port power supply, 3 represents starboard power supply, 4 represents double-terminal power supply, unimportant load 1 represents no power supply, 2 represents power supply, the bus switch is similar to double-terminal power supply equipment.

Assume that the state of area 1 before the fault is 4322, that is, the generator is powered by both ends, the secondary load is powered by the right bus, the unimportant load is online, the bus switch sw6 is closed and sw7 is opened, and after 5 seconds, the port bus in area 1 and the secondary in area 2 The failure of the load to the right chord bus branch causes the failure of the communication line of sw4 to cause its state to be unsatisfactory, the failure of sw5 to cause its opening to be uncontrollable, and the failure of sw11 to be unsatisfactory and uncontrollable. As shown in Figure 3. The illegal state is defined as the important load power off and the load is powered by two paths. For area 1, according to the second section,

have The system can perform fault-tolerant control, that is, when the secondary load is in state 3, sw4 is prohibited from closing, and when the fault is isolated, the system can perform recovery operations. The recoverable state set is:

Q _{re, j} = {1111, 1121, 1311, 1321, 3111, 3121, 3311, 3321}

Calculated, For all 128 states, satisfy /> Restoration is possible.

Initial state x(0)={4322} after a fault, since there is a disable event sw5 closed, then After 2 seconds, it is observed that the uncontrollable event sw5 is turned on, then x(1)={4122}, the same reason /> because Then the recovery operation cannot be performed at this time.

For zone 2, There are 160 states that will not be listed in this article. When sw24 is turned on in area 3, the recoverable state set is:

Assuming that the state of area 2 before the fault is 4234, the initial state x(0)={4234} after the fault, and there are disabled events sw10 and sw13 closed, then Then area 2 cannot be reconstructed. In this paper, 8s simulation is carried out, and the simulation is shown in Figure 5.

The simulation shows that after a fault occurs in the 5th second, the system power drops by 2MW, and the system power is 78MW when sw5 is turned on in the 7th second, and then the system is reconfigured at this time, that is, sw5 is closed, and the system power rises to 80MW.

The invention can estimate part of the observable system state, increase the reconstruction application scene, and improve the response ability of the system under failure.

The above descriptions are only embodiments of the present invention, and are not intended to limit the present invention. Various modifications and variations of the present invention will occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims (4)

1. A ship comprehensive power system reconstruction method considering communication faults is characterized in that: the reconstruction method utilizes state estimation to complete reconstruction, and specifically comprises the following steps:

step 1: starting to wait for an observable event, if the occurrence of the event is observed, performing step 2, otherwise, waiting for the observable event;

step 2: performing state estimation;

step 3: judging whether the system can perform fault-tolerant control, if so, disabling a corresponding event by the controller, otherwise, sending a signal of non-fault-tolerant control;

step 4: judging whether the system fails, if so, performing step 5, otherwise, returning to step 1;

step 5: judging whether the system can perform recovery operation or not, if so, triggering a corresponding event sequence by the controller after the staff agrees to perform recovery operation so that the system enters a recoverable state to wait for recovery event occurrence, otherwise, sending a signal that recovery operation cannot be performed;

step 6: if the recovery operation is not currently possible, performing the reconstruction operation on the system with the maximum recovery load power as a target, and waiting for the recovery operation, wherein:

the state estimation in the step 2 specifically includes the following steps:

step 2-1: calculating the state of the system after the event observed at the moment according to the current state of the system;

step 2-2: calculating the state of the system after all the unobservable events occur when the system is in the state obtained in the step 1;

step 2-3: if the unobservable range does not exist, setting the controller to be empty, otherwise, calculating a forbidden event in the controller;

step 2-4: outputs a state estimate and events disabled in the state estimate based controller,

after the state estimation is performed in the step 2, whether an uncontrollable event exists in the state needs to be checked to enable the system to enter an illegal state, and if yes, the last controllable event in the prefix symbol string of the uncontrollable entering the illegal state is forbidden.

2. The method for reconstructing the comprehensive power system of the ship taking communication faults into consideration as recited in claim 1, wherein the method comprises the following steps of: modeling the ship comprehensive power system by adopting a hybrid automaton, and dividing the ship comprehensive power system into three parts: the system comprises a discrete controller, an interface and a continuous controlled system, wherein the behavior of the discrete controller is controlled by discrete input and discrete events at the interface, the interface consists of an event generator and a control behavior generator, the continuous controlled system is described by a differential equation, and the behavior of the continuous controlled system is influenced by continuous input and continuous disturbance.

3. The ship integrated power system reconstruction method considering communication faults according to claim 1 or 2, wherein: the ship comprehensive power system is represented by a hybrid automaton H:

H＝(Q，X，U，Init，f，∑，EG，T，R)

wherein: q represents a set of all discrete states;representing a set of continuous states in discrete states, Q.u.X representing a state space, Q being a finite set; />Is a continuous set of control inputs; />Representing an initial set of conditions; f: q X U → X is used to describe the evolution law of Q ε Q in continuous state, Σ= Σ _c ∪∑ _uc Is a collection of discrete events Σ _c Representing a set of controllable events, Σ _uc Is an uncontrollable event set; EG is an event generator function; t: Σxq→2 ^Q Representing discrete state transition relationships; r: q X U2 ^X×U Is a reset relationship and also represents a control behavior generator function.

4. The method for reconstructing the comprehensive power system of the ship taking communication faults into consideration as recited in claim 2, wherein the method comprises the following steps of: the fault-tolerant control in the step 3 has a control strategy of:

when the conditions are met, the discrete controller enables the ship comprehensive power system to never enter an illegal state;

define all state sets Q that enter the return to normal operation configuration _re，j The method comprises the following steps:

the saidWhen the comprehensive power system of the ship meets the fault-tolerant control condition, when the comprehensive power system of the ship meets the fault-tolerant control conditionWhen the integrated power system of the vessel is reconfigurable, the presence controller phi (q) makes it possible to return the integrated power system of the vessel to a normal state,