CN105301963B - A kind of thrust optimizing distribution method based on ship power management system - Google Patents

Abstract

The invention discloses a thrust optimization distribution method based on a ship power management system. The controller obtains the resultant force and the resultant force distance that need to be distributed currently, and then adopts the basic thrust distribution method to optimize the thrust distribution for the given thrust, and sends the optimization result to the The power management system analyzes and judges, and if it does not meet the requirements of the power grid, optimizes the secondary thrust distribution; the power management system adjusts the entire ship's power grid according to the thrust after the secondary distribution. The present invention adopts the propeller offset thrust optimization distribution method to adjust the power of the propeller, thereby adjusting the power grid of the whole ship. Reduce host wear and energy consumption.

Description

A Thrust Optimal Allocation Method Based on Ship Power Management System

technical field

The invention relates to a thrust distribution method for a dynamic positioning ship, in particular to a thrust optimization distribution method based on a ship power management system.

Background technique

The 21st century is the era of marine economy. With the rapid rise of the marine industry, the dynamic positioning system has become an important part of offshore operations for offshore engineering ships\platforms such as offshore drilling platforms, lifting pipe-laying ships, cable-laying ships, and platform supply ships. In particular, it is an indispensable support system for deep sea operations, and it is an indispensable marine engineering equipment for my country to accelerate the development of marine resources.

The dynamic positioning system of a ship refers to the use of its own propulsion device to effectively generate reaction forces and moments to resist the effects of wind, waves, currents and other external forces on the ship without anchoring, so that the ship can be kept at the set position and heading, or the ship can be accurately positioned. A system that tracks a given trajectory. The dynamic positioning system is composed of a filter, a controller, and thrust optimization distribution; the filter eliminates the high-frequency information from the sensor and sends it to the controller, and the controller calculates the force required to return to the set position and heading according to the position and heading deviation And moment, thrust optimization distribution According to the force and moment calculated by the controller, the thrust of each propeller on the ship is optimized, and then the control command of each propeller is obtained, so that the ship returns to the set position and heading.

Since the ship adopting the all-electric propulsion method does not need the shafting of the traditional mechanical propulsion method, it has the advantages of layout flexibility; the number of operating generator sets can be adjusted arbitrarily according to the change of the ship's speed, displacement and power load on the ship, which has high efficiency. , energy saving and other good economy. At present, the all-electric propulsion method has become the standard propulsion method for offshore engineering ships, especially those equipped with dynamic positioning systems.

In addition to the thruster loads that account for the larger power of the ship, there are other loads such as heave compensators, cranes, winches, pumps, drilling systems, etc. on a dynamic positioning ship. The large impact caused by the ship's power system will affect the frequency and voltage changes of the entire ship's power grid, which will increase the wear and energy consumption of the generator set, and even cause the entire ship's power system to fail. The existing thrust distribution method only calculates the optimal speed or pitch, azimuth or rudder of each propeller according to the resultant force and force distance given by the DP (dynamic positioning) controller or the Joystick (joystick) controller. Angle command, without taking into account the impact of thruster load regulation and other sudden changes in load power on the frequency and voltage of the entire ship's grid, and the impact on the energy efficiency and wear of the generator set.

The application number is 201210177475.9, and the invention patent titled "A Dynamic Positioning Ship Thrust Distribution Method Based on Thrust Distribution Management" has invented a ship dynamic positioning system thrust distribution method, but the invention is only a method obtained through thrust distribution calculation The method of propeller thrust. The application number is 201210177458.5, and the invention patent titled "Dynamic Positioning Ship Thruster Load Limiting Method Based on Online Available Power" has invented a dynamic positioning ship propeller load limiting method based on online available power. The load limiting factor of the propeller controls the propeller to prevent its overload, but does not take into account the influence of other high-power loads on board and the dynamic characteristics of the power station on the power grid.

Contents of the invention

Purpose of the invention: The present invention aims to provide a system based on ship power management, which can adopt a propeller biased secondary thrust optimization distribution method based on the rate of change of other loads on the ship when the ship is subjected to other loads and sudden changes in the environment Dynamically adjust the thrust of the propeller, thereby adjusting the entire ship's power system, so that the frequency and voltage of the entire ship's power grid fluctuate within an appropriate range, prevent the power failure of the ship's power system, improve the safety of the ship's offshore operations, and reduce the wear and tear of the ship's propulsion system. energy consumption.

Technical solution: a thrust optimization allocation method based on a ship power management system, including the following steps:

A) The thrust distribution unit obtains the resultant force and resultant distance that need to be distributed currently from the DP controller or the Joystick controller;

B) using the basic thrust distribution method to optimize the thrust distribution of the resultant force and the resultant moment, and send the thrust and the minimum propulsion power of the propeller calculated by optimization to the power management system;

C) The power management system analyzes according to the heavy load request of other loads at the moment, the current propeller power consumption, the total remaining power of the whole ship, the operation status of the ship power grid, and the minimum required propulsion power, and judges whether the current required power consumption is in the power grid The frequency and voltage fluctuation range and whether the economic benefits are optimal, if the above conditions are met, the thrust allocation unit sends the thruster instructions optimized and calculated by the basic thrust allocation method to each thruster; if not satisfied, use the power Adjust the thrust distribution method for secondary distribution;

D) The thrust distribution unit selects the bias power of the propeller according to the maximum allowable power of the propulsion system given by the power management system, other load power changes, and the current power consumption of the propeller, and uses the power adjustment thrust distribution method to optimize the secondary thrust distribution, and Send the assigned thrust value of each thruster to the power management system;

E) The power management system controls the start and stop of diesel engines in the power grid, adjusts the speed of diesel engines, the status of main circuit breakers, the status of generators and the status of propellers according to the thrust size after the secondary distribution of the power adjustment thrust distribution method in the thrust distribution unit, thereby adjusting The voltage and frequency of the whole ship's power grid to prevent the power outage of the whole ship's power grid.

Preferably, the power adjustment thrust allocation method described in step D) uses the minimum power, thrust, the difference between the propeller power change rate and other load power change rates and thrust error as the thrust allocation purpose, and uses thrust balance, power constraint, propeller The dynamic thrust range is a constraint condition, and the Lagrangian optimization method is used for optimization, and the thrust distribution model adopted is:

st.B(a)Kf=τ _d +s

P _max ≥P _c K|f| ^3/2 ≥P _min +P _bias

f ^- ≤ f ≤ f ⁺

Among them, P _c is the power relationship vector, K is the thrust coefficient matrix, f is the thrust of the thruster, Ψ is the weight matrix, Θ is the power difference change rate factor, is the propeller power change rate, is the change rate of other load power, Q is the weight matrix, s is the relaxation factor to ensure that the thrust distribution has a solution, B(a)Kf is the thrust equation, τ _d is the resultant force and moment, P _max is the maximum available power of the current propeller, P _min is the minimum available power of the current thruster, P _bias is the bias power value of the thruster, f ^- is the lower limit of the current thrust of the thruster, and f ⁺ is the upper limit of the current thrust of the thruster.

Beneficial effect:

1. The thruster biasing method adopted in the present invention enables the thrusters to produce mutual thrusts without changing the resultant force and resultant force distance produced by all propellers of the whole ship, which makes up for the shortcoming of the slow response of the diesel engine turbocharging system and improves The whole ship's power system responds quickly to sudden load changes; this method adjusts the whole ship's power grid through the power management system, uses the least number of generators online, avoids diesel engines running at a power far below the rated power for a long time, improves fuel efficiency, and reduces emissions , which reduces the wear and tear of the propulsion unit, and the economic benefits brought by the propeller bias are far greater than the energy consumption increased by the bias.

2. Based on the ship power management system, the present invention adopts the propeller bias method to optimize the distribution of thrust and dynamically adjust the power of the propeller, thereby adjusting the power of the whole ship, so that the power system of the whole ship can withstand other sudden load changes and a certain generator failure. 1. Partial loop short-circuit failure of the power system prevents power failure of the whole ship's power system and improves the safety of the ship.

Description of drawings

Fig. 1 is the control structure diagram that the present invention is applied to the dynamic positioning system of the ocean engineering ship and the power station system;

Figure 2 is a structural diagram of the power system of an ocean engineering ship.

Detailed ways

The present invention will be described in more detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the dynamic positioning system of an ocean engineering vessel and the power station system control system include: power management system, power station, ship propeller, other loads, DP controller or Joystick controller, thrust distribution unit, and the thrust distribution unit includes basic The thrust distribution unit and the power adjustment thrust distribution unit, wherein the basic thrust distribution unit uses the basic thrust distribution method, and the power adjustment thrust distribution unit uses the power adjustment thrust distribution method.

A thrust optimization distribution method based on a ship power management system of the present invention comprises the following steps:

1. The DP controller or Joystick controller calculates the resultant force and resultant moment τ _d of the ship’s surge, sway and yaw directions according to the difference between the ship’s feedback position and heading signal and the set value, and calculates τ _d to the thrust distribution unit.

2. The basic thrust allocation unit uses the basic thrust allocation method to optimize the thrust allocation for the given τ _d , and sends the optimized calculation results: the thrust f of each ship propeller to the power management system, and the required minimum propulsion power P _min It is sent to the power management system; the basic thrust allocation method takes the minimum power and thrust error as the thrust allocation purpose, takes the thrust balance and the mechanical characteristics of the ship propeller as constraints, and adopts the Lagrangian optimization method for optimization. The thrust allocation model adopted is :

st.B(a)Kf=τ _d +s (2)

f ^- ≤ f ≤ f ⁺ (3)

Among them, P _c is the power relationship vector, K is the thrust coefficient matrix, f is the thrust of the thruster, Q is the weight matrix, s is the relaxation factor to ensure that the thrust distribution has a solution, B(a)Kf is the thrust equation, τ _d is Resultant force and resultant moment, f ^- is the lower limit of the current thrust of the propeller, and f ⁺ is the upper limit of the current thrust of the propeller.

3. The power management system analyzes according to the heavy load request of other loads at the moment, the current ship propeller power consumption P _prev , the total remaining power of the ship, the operation status of the ship power grid, and the required minimum propulsion power P _min to judge the current required power. Whether the power consumption is within the frequency and voltage fluctuation range of the power grid and whether the economic benefits such as diesel engine energy consumption are optimal. If the above conditions are met, the thrust distribution unit converts the thrust f of each ship propeller calculated by the optimal calculation of the basic thrust distribution method into The corresponding ship propeller speed and azimuth angle control commands are sent to each ship propeller; if not satisfied, use the power adjustment thrust distribution method to perform secondary distribution on the given τ _d .

4. The thrust distribution unit selects the appropriate ship propeller bias power value P _bias according to the maximum allowable power P _max of the propulsion system given by the power management system, other load power changes P _ff , and current ship propeller consumption power P _prev , using The power adjustment thrust allocation method performs the secondary thrust optimal allocation under given conditions. The power adjustment thrust allocation method uses the minimum power, thrust, the difference between the ship propeller power change rate and other load power change rates, and thrust error as the thrust allocation purpose. Taking the thrust balance, power constraint, and ship propeller mechanical characteristics as constraints, the Lagrangian optimization method is used for optimization, and the thrust distribution model adopted is:

st.B(a)Kf=τ _d +s (5)

P _max ≥P _c K|f| ^3/2 ≥P _min +P _bias (6)

f ^- ≤ f ≤ f ⁺ (7)

Equation (4) is the optimized objective function, the first item is the propeller power of the ship, the second item is the thrust of the ship propeller, the third item is the difference between the power change of the ship propeller and other load power changes, and the fourth The term is the error for a given thrust _τd and the thrust B(a)Kf after distribution.

Equation (5) is given the first equality constraint for the objective function (4), which requires that after allocation be equal to the given value τ _d .

Equation (6) is the constraint on the propeller power of the ship, which requires the power of the propeller to be greater than the sum of the required minimum propulsion power P _min and the bias power P _bias of the ship propeller, and less than the maximum allowable power P of the given propulsion system _max .

Equation (7) is the constraint on the thrust change rate of the ship propeller, which takes into account factors such as the maximum and minimum thrust values and the maximum and minimum change rates of the thrust determined by the propeller size and mechanical characteristics of each ship.

The goal of the power adjustment thrust distribution method is to minimize Equation (4) and satisfy the constraints of Equations (5), (6), and (7) to obtain the thrust f of a ship propeller, where τ _d is the DP controller Control quantity, ship thruster bias power P _bias and other load power change rates is the control quantity of the power management system, the ship propeller thrust and power relationship vector P _c , the thrust coefficient matrix K, the lower limit f ^- of the dynamic change of the ship propeller thrust, and the upper limit f ⁺ of the dynamic change of the ship propeller thrust are determined by the Determined by the physical characteristics of the ship propeller, the weight matrix Ψ and Q, and the power difference change rate factor Θ are the parameters that need to be adjusted during the optimization process.

5. The power management system regulates the power grid voltage of the whole ship by controlling the diesel engine start and stop, diesel engine speed, main circuit breaker, generator and other equipment in the power grid according to the thrust f after the secondary distribution of the thrust distribution method in the thrust distribution unit. , frequency, prevent power outage of the whole ship's power grid, improve the safety of the ship, and reduce the wear and tear of the main engine and energy consumption.

Combined with Figure 2 to illustrate how the power management system regulates the entire ship power grid:

The power management system can control generator sets G1, G2, G3, adjust the speed of diesel engine 1, diesel engine 2, and diesel engine 3, control whether generator 1 is connected to the grid through main circuit breaker CB1, and control whether ship propeller 1 is available through main circuit breaker CB2 , through the main circuit breaker CB3 to control whether to connect to other transmission network segments, and through the frequency converter FC to adjust the speed of the propulsion motor M1, thereby adjusting the voltage and frequency range of the entire ship’s power grid, optimizing the quality of the entire ship’s power grid, and preventing the power outage of the entire ship’s power grid.

Combined with Table 1, the effect of this thrust distribution method is illustrated:

Assuming that generator sets 1, 2, and 3 in Figure 2 are the same, the dynamic load change rate that each generator set can withstand is 30% of the rated capacity, and the power requested by other load devices from the power management system is the capacity of a single generator set 90% of the propulsion power required for DP positioning is 90% of the rated capacity of a single generator set. When the ship is performing DP operations, it is necessary to completely ensure that the power system is continuously powered. Set the bias power of the ship propeller to the capacity of a single generator set 30% of. Table 1 shows the operation status of the whole ship's power system after the propeller biased thrust distribution is adopted:

Table 1:

It can be seen from Table 1 that the system requirements cannot be met by running two generators without using the propeller bias power adjustment thrust distribution method, and all three generators need to be operated to prevent the power grid from being cut off; using the ship propeller bias power adjustment Thrust distribution method running 2 generator sets can prevent the power grid from being cut off. Although the ship propeller bias consumes a lot of power, when running 3 generator sets, it will run at 30% load for a long time. At this time, the generator sets will wear out greatly, Poor energy efficiency, poor emissions, far less economical than running 2 generators.

Claims (2)

1. A thrust optimization distribution method based on ship power management system, is characterized in that, comprises the steps: A) The thrust distribution unit obtains the resultant force and resultant distance that need to be distributed currently from the DP controller or the Joystick controller; B) using the basic thrust allocation method to optimize the thrust distribution of the resultant force and the resultant moment, and send the thrust calculated by optimization and the minimum required propulsion power to the power management system; C) The power management system analyzes according to the heavy load request of other loads at the moment, the current propeller power consumption, the total remaining power of the whole ship, the operation status of the ship power grid, and the minimum required propulsion power, and judges whether the current required power consumption is in the power grid The frequency and voltage fluctuation range and whether the economic benefits are optimal, if the above conditions are met, the thrust allocation unit sends the thruster instructions optimized and calculated by the basic thrust allocation method to each thruster; if not satisfied, use the power Adjust the thrust distribution method for secondary distribution; D) The thrust distribution unit selects the bias power of the propeller according to the maximum allowable power of the propulsion system given by the power management system, other load power changes, and the current power consumption of the propeller, and uses the power adjustment thrust distribution method to optimize the secondary thrust distribution, and Send the assigned thrust value of each thruster to the power management system; E) The power management system controls the start and stop of diesel engines in the power grid, adjusts the speed of diesel engines, the status of main circuit breakers, the status of generators and the status of propellers according to the thrust size after the secondary distribution of the power adjustment thrust distribution method in the thrust distribution unit, thereby adjusting The voltage and frequency of the whole ship's power grid to prevent the power outage of the whole ship's power grid. 2. A kind of thrust optimization distribution method based on ship power management system according to claim 1, it is characterized in that, described in step D) the power adjustment thrust distribution method is based on minimum power, thrust, thruster power change rate and other The difference between the load power change rate and the thrust error is the purpose of thrust allocation, and the thrust balance, power constraint, and propeller dynamic thrust range are taken as constraints, and the Lagrangian optimization method is used for optimization. The thrust allocation model adopted is: <mfenced open = "" close = ""><mtable><mtr><mtd><munder><mrow><mi>m</mi><mi>i</mi><mi>n</mi></mrow><mrow><mi>f</mi><mo>,</mo><mi>s</mi><mo>,</mo><msub><mi>&amp;tau;</mi><mi>e</mi></msub></mrow></munder></mtd><mtd><mrow><msub><mi>P</mi><mi>c</mi></msub><mi>K</mi><msup><mrow><mo>|</mo><mi>f</mi><mo>|</mo></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msup><mo>+</mo><msup><mi>&amp;Psi;</mi><mi>T</mi></msup><mi>K</mi><mi>f</mi><mi>&amp;Psi;</mi><mo>+</mo><mi>&amp;Theta;</mi><msup><mrow><mo>(</mo><msub><mover><mi>P</mi><mo>&amp;CenterDot;</mo></mover><mrow><mi>t</mi><mi>h</mi></mrow></msub><mo>-</mo><msub><mover><mi>P</mi><mo>&amp;CenterDot;</mo></mover><mrow><mi>f</mi><mi>f</mi></mrow></msub><mo>)</mo></mrow><mn>2</mn></msup><mo>+</mo><msup><mi>Q</mi><mi>T</mi></msup><mi>s</mi><mi>Q</mi></mrow></mtd></mtr></mtable></mfenced> st.B(a)Kf=τ _d +s P _max ≥P _c K|f| ^3/2 ≥P _min +P _bias f ^- ≤ f ≤ f ⁺ Among them, P _c is the power relationship vector, K is the thrust coefficient matrix, f is the thrust of the thruster, Ψ is the weight matrix, Θ is the power difference change rate factor, is the propeller power change rate, is the change rate of other load power, Q is the weight matrix, s is the relaxation factor to ensure that the thrust distribution has a solution, B(a)Kf is the thrust equation, τ _d is the resultant force and moment, P _max is the maximum available power of the current propeller, P _min is the minimum available power of the current thruster, P _bias is the bias power value of the thruster, f ^- is the lower limit of the current thrust of the thruster, and f ⁺ is the upper limit of the current thrust of the thruster.