CN103332284A - Energy management and control method for electric propulsion system of hybrid power ship - Google Patents

Abstract

The invention provides an energy management and control method of a hybrid ship electric propulsion system, so as to obtain the minimum energy consumption, minimum emission, and maximum endurance, and ensure the performance of the ship power system as the ultimate goal. The hybrid ship electric propulsion system includes: an energy system, an electric propulsion device, a charging device, a DC bus, an energy conversion device and an energy management system. The energy management and control method controls the supply and conversion of the ship's hybrid power energy in two working modes, and the method includes: (1) Obtaining the current power demand of the ship, (2) Obtaining the SOC value of the lithium battery through the CAN bus, ( 3) Provide energy control rules. It realizes the reasonable distribution of multi-energy in the hybrid ship electric propulsion system, improves the energy utilization efficiency, can recover excess energy, obtains the least energy consumption, the least emission, the maximum endurance, and guarantees the goal of the ship's power system performance.

Description

An energy management and control method for a hybrid ship electric propulsion system

technical field

The invention belongs to the technical field of ship electric propulsion, and in particular relates to an energy management and control method of a hybrid ship electric propulsion system.

Background technique

The hybrid ship propulsion system can make full use of diesel-electric power generation, wind energy, solar energy and battery energy storage, which can save fuel and reduce operating costs. It is a comprehensive and optimal utilization system for ship energy with great development prospects. The hybrid electric propulsion system is the latest technology to solve the energy saving and emission reduction of ships, and it is the combination of diesel electric propulsion and pure electric propulsion. This technology applies renewable emerging energy technologies such as light energy and wind energy. Its key core and hub are energy management and control strategies. The hybrid ship energy management system has the characteristics of complex structure and extensive use of nonlinear power electronic equipment. A nonlinear system that combines mechanical, electrical, chemical, and thermodynamic systems. The main function of the hybrid ship energy management system is to control ship power control and work mode switching. By commanding the coordination of various subsystems, it can achieve the best efficiency, emission and power performance, while taking into account the stability and stability of the sailing ship. safety. The mixed access of multiple energy sources will cause various instantaneous interferences to the ship power system, including energy mixed interference and harmonic interference generated by energy conversion, which will affect the navigation safety of the ship. Choosing a reasonable and optimal control strategy will improve the ship's safety and stability. At present, domestic research on the energy management strategy of hybrid ship electric propulsion system is very little, and it is still in the initial stage. development is of great significance.

Contents of the invention

In view of the above-mentioned current situation and the problems existing in the related technologies, the present invention provides an energy management and control method for the electric propulsion system of a hybrid ship, so as to obtain the minimum energy consumption, minimum emission, and maximum endurance, and ensure the performance of the ship's power system as the ultimate goal .

The present invention proposes a hybrid ship electric propulsion system consisting of the following parts:

(1) Energy system. The energy system includes diesel generator sets (referred to as: diesel generator sets), lithium batteries, super capacitors and solar photovoltaic cells.

(2) Electric propulsion device. The electric propulsion device consists of a frequency converter, a propulsion motor, an operating console and a propeller.

(3) Charging device. The charging device is divided into a DC charging device and an AC charging device.

(4) DC bus. The DC bus is the confluence point of the energy system, and all the energy is aggregated to the bus in the form of DC, and then sent to the electric propulsion device.

(5) Energy conversion device. Energy conversion devices are divided into: AC/DC, DC/DC, DC/AC.

(6) Energy management system. The energy management system reasonably allocates the energy output of diesel generator sets (abbreviation: diesel generator sets), lithium batteries, and super capacitors according to system requirements.

During normal navigation, the working conditions of the hybrid ship electric propulsion system are divided into two types: the diesel-electric unit is used as the main power source, and the lithium battery is used as the auxiliary power source. This working condition is working mode 1; the lithium battery is used as the main power source. , the diesel-electric unit is used as the auxiliary power source, and this working condition is working mode 2.

(1) Working mode 1. The diesel generator set in the system is always running under the best efficiency working condition, and its output power P _e is a fixed value. When the ship’s demand power P _l is less than the power P _e provided by the diesel generator set, the diesel generator set can provide energy for the ship , can also charge lithium batteries and supercapacitors. When the power P _l required by the ship is greater than the power P _e provided by the diesel generator set, the system energy is supplemented by discharging the lithium battery (output power is P _b ).

(2) Working mode 2. According to the working characteristics of the lithium battery, when its state of charge (SOC) can meet the power demand of the system, the lithium battery will provide all the energy. When the SOC drops to a certain level, it is necessary to start the diesel generator set to meet the power demand of the system. After that, the system switches to the diesel generator set as the main power source, and the lithium battery and other energy sources are used as the auxiliary power source. When the lithium battery SOC can meet the ship's power requirements alone, it can switch to the lithium battery as the main power source.

The energy demand at the moment of starting will be large, and the large energy at the moment of starting will be supplemented by the discharge of the super capacitor.

When the ship is docked, the lithium battery and supercapacitor are charged by the shore power.

When the diesel generator set charges the lithium battery and super capacitor, its output power is P _ec ; when the solar photovoltaic battery charges the lithium battery and super capacitor, its output power is P _sc , when the ship brakes, the feedback energy is sent to the lithium battery and The supercapacitor is charged with a power of P _bc .

Solar photovoltaic cells can always charge lithium batteries and supercapacitors.

In order to achieve the minimum energy consumption, minimum emission, and maximum endurance, and ensure the performance of the ship's power system, the energy management and control method of the hybrid ship's electric propulsion system includes the following steps:

(1) Obtain the current required power of the ship. When the current ship is sailing, the current torque T ₀ is obtained through the torque sensor, and the current speed n ₀ is obtained by the rotational speed sensor, so as to obtain the current required power P ₀ of the ship.

(2) The system can obtain the SOC value of the lithium battery through the CAN bus.

(3) Energy control rules:

1) The priority of mode 2 is higher than that of working mode 1, that is, as long as the conditions of working mode 2 are met, the system will preferentially enter the working mode of working mode 2.

2) If SOC≥50%, the system enters working mode 2, at this time P _l =P _b , P _e =0.

3) If 30%≤SOC<50%, the system exits working mode 2 and enters working mode 1. If P _l ≤ P _e , P _l =P _e -P _ec , the charging state of the lithium battery; if P _l >P _e , P _l =P _e + P _b , the diesel generator set and the lithium battery are mixed for power supply.

4) If SOC<30%, the system enters working mode 1, if P _l ≤ P _e , P _l =P _e -P _ec , the charging state of the lithium battery; if P _l >P _e , the system performs power limitation, and the system requires power Limit at P _l =P _e , until SOC>30%, cancel the power limit, return to 3). If SOC≥50%, the system returns to 2).

It can be known from the above technical solution that the present invention proposes an energy management and control method for a hybrid ship electric propulsion system, which can realize the rational distribution of multiple energies in the hybrid ship electric propulsion system, improve the utilization efficiency of energy, and recover excess energy. Energy, which can achieve the goal of minimum energy consumption, minimum emission, maximum endurance, and guarantee the performance of the ship's power system.

Description of drawings

Fig. 1 is a structural diagram of a hybrid ship electric propulsion system of the present invention;

Fig. 2 is the power analysis graph when the diesel unit of the hybrid ship electric propulsion system of the present invention is used as the main power source;

Fig. 3 is the power analysis graph when the lithium battery of the hybrid ship electric propulsion system of the present invention is used as the main power source;

Fig. 4 is a flow chart of the energy control rules of the present invention.

Detailed ways

In order to make the means, purpose and final effect of the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations.

The structure of a hybrid ship electric propulsion system is shown in Figure 1, and the direction of the solid arrow is the direction of energy flow.

(1) The energy system is composed of diesel generator sets, lithium batteries, supercapacitors and solar photovoltaic cells. Among them, the diesel generator set can output 400V alternating current; the lithium battery, super capacitor and photovoltaic battery all output direct current. the

(2) The electric propulsion device consists of frequency converter, propulsion motor, operation console and propeller.

(3) The charging device is divided into a DC charging device and an AC charging device. Among them, the DC charging device is mainly used for photovoltaic cells to charge lithium batteries and supercapacitors; the AC charging device is mainly used for shore power and diesel generators to charge photovoltaic cells for lithium batteries and supercapacitors.

(4) DC bus. The DC bus is the confluence point of the energy system, and all the energy is aggregated to the bus in the form of DC, and then sent to the electric propulsion device. It connects three sets of energy conversion devices: AC/DC, DC/DC, and DC/AC.

(5) Energy conversion device. Energy conversion devices are divided into: AC/DC, DC/DC, DC/AC. Among them, AC/DC is used to convert the alternating current generated by the diesel generator set into direct current and send it to the DC bus; DC/DC is used to control the energy flow direction between the lithium battery and the DC bus; DC/AC is used for the DC bus. The electrical energy is converted into alternating current and sent to the electric propulsion unit.

(6) Energy management system. According to the actual working conditions and power requirements of the system, combined with energy control rules to achieve effective energy utilization, reduce energy consumption and emissions, and ensure maximum battery life.

An energy management and control method for a hybrid ship electric propulsion system provided by the present invention comprises the following steps:

(1) The diesel-electric unit is used as the main power source, and other energy sources such as lithium batteries are used as the auxiliary power source, as shown in Figure 2. In the system, the diesel generator set is always running at the best efficiency working state (fixed power output), when the energy demanded by the ship (area 0y ₁ at ₀ ) is less than the energy provided by the diesel generator set (area 0yat ₀ ), at this time, area A is diesel At this time, the diesel-electric unit can charge energy storage devices such as lithium batteries to recover excess energy. When the energy required by the ship (area t ₀ ambt ₁ ) is greater than the energy provided by the diesel generator set (area abx ₂ x ₁ ), at this time area B is the energy that the system still lacks. In this case, the system energy is supplemented by discharging the lithium battery. The area t ₀ ambt ₁ is a mixed power supply area.

(2) The lithium battery is used as the main power source, and other energy sources such as diesel generator sets are used as the auxiliary power source, as shown in Figure 3. According to the working characteristics of the lithium battery, when its SOC can meet the system power demand, the lithium battery will provide all the energy (area 0y ₁ mbt ₀ ), when the SOC drops to a certain level, it is necessary to start the diesel generator set to meet the system power demand. Start the diesel generator set from point a. At this time, the working condition is the same as (1), until the lithium battery SOC alone can meet the power demand of the ship, stop the diesel generator set.

(3) Since the supercapacitor has the characteristics of high current and rapid charge and discharge, when starting, the supercapacitor can be used in conjunction with the diesel generator set and lithium battery to supplement the large energy at the moment of starting; when braking, the supercapacitor can be used to quickly recover energy.

(4) When the ship is docked, the lithium battery and supercapacitor are charged by the shore power to ensure the energy of the lithium battery and supercapacitor.

(5) When the ship sails normally, the energy control rules are as follows:

1) The priority of mode 2 is higher than that of working mode 1, that is, as long as the conditions of working mode 2 are met, the system will preferentially enter the working mode of working mode 2.

2) If SOC ≥ 50%, the system enters working mode 2, the power required by the ship is all provided by the lithium battery, and the lithium battery is in the discharge state, at this time P _l =P _b , P _e =0.

3) If 30%≤SOC<50%, the system exits working mode 2 and enters working mode 1, and the diesel generator set operates in the working state with the best efficiency and constant power output. If P _l ≤ P _e , P _l =P _e -P _ec , the diesel generator set is in the power supply state, and the lithium battery is in the charging state; if P _l ＞P _e , P _l =P _e + P _b , the diesel generator set and the lithium battery Battery hybrid.

4) If SOC < 30%, the system enters working mode 1, and the diesel generator set operates at the best efficiency working state, with constant power output. If P _l ≤ P _e , P _l =P _e -P _ec , the diesel generator set is in the power supply state, and the lithium battery is in the charging state; if P _l >P _e , the system performs power limitation, and the system demand power is limited to P _l =P _e , until the SOC > 30%, cancel the power limit, back to 3). If SOC≥50%, the system returns to 2).

The present invention is not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the present invention. within the scope of protection.

Claims (1)

1. energy management and the control method of a hybrid power boats and ships electric propulsion system, described hybrid power boats and ships electric propulsion system comprises: energy resource system, electric propulsion apparatus, charging unit, dc bus, energy conversion device and energy management system, described energy resource system comprises diesel powerplant, lithium cell, super capacitor and solar-energy photo-voltaic cell, it is characterized in that energy management and the control method of described hybrid power boats and ships electric propulsion system comprise:

(1) obtains the current demand power of boats and ships: during described ship's navigation, obtain current torque by torque sensor, obtain current rotating speed by tachogen, thereby obtain the current demand power of described boats and ships;

(2) obtain described lithium cell SOC value by the CAN bus;

(3) provide the energy control law:

When a. described boats and ships pull in to shore, give described lithium cell and the charging of described super capacitor by the bank electricity, guarantee the energy of described lithium cell and described super capacitor;

When b. starting, use described super capacitor cooperate described diesel powerplant and described lithium cell replenish starting moment than macro-energy, during drag, use the quick recuperated energy of described super capacitor;

C. in normal navigation process, described hybrid power boats and ships electric propulsion system operating mode be divided into two kinds: described diesel powerplant is made main power, described lithium cell is made auxiliary power source, this operating mode is mode of operation 1, described lithium cell is made main power, described diesel powerplant is made auxiliary power source, and this operating mode is mode of operation 2, and described boats and ships demand power is P _l, the power that described diesel powerplant provides is P _e, described lithium cell discharge rate is P _b, the energy control law is as follows:

C1) pattern 2 priority are higher than mode of operation 1, as long as just satisfy under the condition of mode of operation 2, system preferentially enters the mode of operation of mode of operation 2;

C2) if SOC 〉=50%, system enters mode of operation 2, this moment P _l=P _b, P _e=0;

C3) if 30%≤SOC＜50%, system's pattern 2 of deactivating enters mode of operation 1, if P _l≤ P _e, P _l=P _e-P _Ec, the lithium cell charging state; If P _l＞P _e, P _l=P _e+ P _b, bavin group of motors and lithium cell hybrid power supply;

C4) if SOC＜30%, system enters mode of operation 1, if P _l≤ P _e, P _l=P _e-P _Ec, the lithium cell charging state; If P _l＞P _e, system carries out Power Limitation, and the system requirements Power Limitation is at P _l=P _e, behind SOC＞30%, the cancellation Power Limitation is got back to c3); If SOC 〉=50%, c2 gets back in system).

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