Solid oxide fuel cell coupled with thermoelectric power generation for ship integrated energy system and method

Abstract

The application discloses a kind of solid oxide fuel cell and temperature difference power generation coupling ship integrated energy system and method, SOFC power generation module utilizes fuel high-efficiency power generation and generates high-temperature tail gas, and high-temperature tail gas heat energy is recycled by waste heat recovery heat exchange module, and heat is transmitted to the high-temperature side of temperature difference power generation module, with sea water as low-temperature cold source to form cold and hot end temperature difference, and realize waste heat power generation. Through energy storage module and DC bus, multi-energy collaborative energy supply is realized, and intelligent energy management method based on model predictive control is used, according to different operating conditions of ship, SOFC output power, TEG working state and energy storage charging and discharging strategy are optimized and controlled, to realize system fuel consumption minimization and comprehensive efficiency maximization. The application can effectively improve SOFC tail gas waste heat utilization rate, improve ship integrated energy system operating efficiency and dynamic response capability, reduce fuel consumption and pollution emission, and is suitable for green intelligent ship, polar ship and new energy ship.

Description

Technical Field

[0001] This invention relates to a ship integrated energy system coupled with a solid oxide fuel cell and thermoelectric power generation, and its control method, belonging to the field of ship new energy and integrated energy utilization technology. Background Technology

[0002] With the International Maritime Organization (IMO) continuously raising its requirements for ship energy efficiency and carbon emissions, traditional diesel engine-based ship propulsion systems face problems such as high fuel consumption, large pollution emissions, and low energy efficiency. This is especially true in the fields of polar vessels, research vessels, cruise ships, and high-end green ships, where the demand for high-efficiency, low-emission, and intelligent integrated energy systems is increasingly urgent. Therefore, developing new clean ship energy systems has become an important direction for the development of current ship propulsion technology.

[0003] Solid oxide fuel cells (SOFCs) are considered an important energy form for future green ships due to their advantages such as high power generation efficiency, strong fuel adaptability, low noise, and low pollution emissions. SOFCs operate under high-temperature conditions, generating a large amount of high-temperature exhaust gas during their electrochemical reactions, with exhaust gas temperatures typically exceeding 600°C. In current technologies, most SOFC exhaust gas waste heat is treated only through simple heat exchange or direct emission, resulting in significant room for improvement in the overall energy utilization efficiency of the system.

[0004] Meanwhile, thermoelectric generators (TEGs) can directly convert heat energy into electrical energy based on the Seebeck effect, featuring compact structure, no moving mechanical parts, high reliability, and suitability for complex marine environments. Particularly in ship environments, seawater can serve as a natural low-temperature cold source, creating a significant temperature difference with SOFC exhaust gas, providing a solid foundation for TEG applications. However, in existing ship energy systems, SOFCs and TEGs often operate independently, lacking efficient coupling and coordinated control mechanisms, making it difficult to fully leverage the advantages of waste heat cascade utilization.

[0005] Furthermore, ship operating conditions are complex and varied, with significant fluctuations in propulsion and daily operating loads under different conditions. For example, port operation, cruising operation, icebreaking operation, and dynamic positioning operation all have different energy demand characteristics. Most existing energy management strategies adopt fixed rule control or single power allocation methods, which are difficult to balance system efficiency, fuel economy, and operational stability. In particular, in multi-energy coupled systems, there is a lack of intelligent control methods for the coordinated optimization of SOFC, TEG, and energy storage.

[0006] Existing related patent technologies, such as the intelligent ship distributed integrated energy management system and energy management method disclosed in patent document (CN113212723A), have significant technical limitations and unresolved "technical problems" in terms of the micro-coupling characteristics of multi-energy devices, dynamic constraints on energy storage status, thermodynamic quality matching, and the robustness of control algorithms. The "electro-thermal coupling cost function" in this patent is mostly a static algebraic equation, failing to consider the dynamic energy efficiency decay caused by equipment thermal inertia, making it difficult to balance system efficiency and operational stability during transient processes. It does not consider thermodynamic temperature stratification and heat dissipation losses, easily leading to actual usable thermal energy being lower than predicted values. It lacks a refined valve opening coordination optimization strategy for prioritizing high-temperature heat sources for high-temperature needs (such as fuel preheating and steam drive) and using low-temperature heat sources for daily heating. It does not constrain the variable load frequency and depth of the hydrogen energy system, making it difficult to achieve a true balance between "fuel economy" and "equipment operational stability / lifespan." Open-loop optimization is difficult to cope with sudden sea conditions: under complex sea conditions (sudden changes in wind, waves, and currents), the load on ships exhibits extremely strong time-varying characteristics. Allocation based on single-prediction and PI control lacks a rolling time-domain closed-loop correction mechanism of model predictive control (MPC). Once a prediction error occurs, the system cannot self-correct in the next time domain.

[0007] While the patent introduces "generalized noise," it fails to consider communication delays, data loss, or local topology faults in the harsh electromagnetic environment of ships. In the absence of event-triggered mechanisms or robust consistency constraints, this can easily lead to power oscillations between multiple energy subsystems.

[0008] Therefore, it is urgent to propose a ship integrated energy system based on SOFC and thermoelectric power generation coupling and its intelligent energy management method, so as to realize the efficient recovery and utilization of SOFC exhaust heat, improve the overall power generation efficiency of the system, reduce ship fuel consumption and carbon emissions, and enhance the dynamic response capability and operational stability of ship energy system under complex operating conditions. Summary of the Invention

[0009] The purpose of this invention is to provide a ship integrated energy system and control method that couples solid oxide fuel cells with thermoelectric power generation, in order to solve the problems of low waste heat utilization, insufficient overall energy efficiency and poor adaptability to dynamic operating conditions in existing ship energy systems.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A ship integrated energy system coupled with a solid oxide fuel cell and thermoelectric power generation includes a fuel supply system, an SOFC power generation module, a thermoelectric power generation module, a waste heat recovery heat exchange module, a ship integrated DC bus, an energy storage module, a DC / DC converter 1, a DC / DC converter 2, a DC / AC converter, an intelligent energy management and control module, ship propulsion loads, and daily loads. The fuel supply system is connected to the SOFC power generation module and is used to supply natural gas, methanol or other hydrogen-containing fuels to the SOFC power generation module; The SOFC power generation module is used to convert the chemical energy of fuel into electrical energy and generate high-temperature exhaust gas. The waste heat recovery heat exchange module is connected to the exhaust gas outlet of the SOFC power generation module to recover the heat energy in the high-temperature exhaust gas of SOFC and form a high-temperature heat source for supplying the thermoelectric power generation module. The thermoelectric power generation module is connected to the waste heat recovery heat exchange module. It utilizes the temperature difference between the high-temperature heat output from the waste heat recovery heat exchange module and the low-temperature cold source to achieve thermoelectric power generation. The thermoelectric power generation module is connected to a seawater cooling system on its low-temperature side, and the cold source is seawater cooling medium. The SOFC power generation module is connected to DC / DC converter 1, the thermoelectric power generation module is connected to DC / DC converter 2, and both DC / DC converter 1 and DC / DC converter 2 are connected to the ship's integrated DC bus. The energy storage module is connected to the ship's integrated DC bus and is used for system peak shaving, power regulation, and transient load compensation. The DC / AC converter is connected between the ship's integrated DC bus and the ship's propulsion load and daily load, and is used to supply power to the AC load. The intelligent energy management and control module is communicatively connected to each functional module to realize system operation status monitoring, energy scheduling, and power coordination control.

[0012] Furthermore, the SOFC power generation module includes a fuel reforming unit, an SOFC stack, an air supply unit, and an exhaust gas emission unit; wherein the SOFC stack operates at a temperature of 600–1000°C.

[0013] Furthermore, the waste heat recovery heat exchange module adopts one or more combinations of plate heat exchangers, finned heat exchangers, or microchannel heat exchangers.

[0014] Furthermore, the thermoelectric power generation module includes a top clamping plate, a high-temperature exhaust channel, a high-temperature side heat-conducting layer, a diffusion heat-equalizing layer, a thermoelectric conversion module, a low-temperature side heat-conducting layer, a seawater channel, and a floor; wherein the thermoelectric power generation unit array of the thermoelectric power generation module is disposed between the high-temperature side heat-conducting layer and the low-temperature side heat-conducting layer.

[0015] Furthermore, the thermoelectric power generation unit in the thermoelectric power generation module is made of Bi2Te3-based, PbTe-based, Skutterudite-based, or semi-Hall materials.

[0016] Furthermore, the seawater cooling system on the low-temperature side of the thermoelectric power generation module includes a seawater pump, a cooling channel, and a flow regulating valve; seawater flows through the cooling channel to the cold end of the thermoelectric power generation module to achieve continuous cooling.

[0017] Furthermore, the energy storage module is a lithium battery pack, a supercapacitor pack, or a combination of both; used to provide transient power support under sudden load changes on the ship.

[0018] Furthermore, the intelligent energy management and control module includes a data acquisition unit, a status monitoring unit, a power distribution unit, and an optimization control unit; the optimization control unit performs comprehensive energy scheduling based on SOFC output power, thermoelectric power generation output power, energy storage charge status, and ship load requirements; the ship's integrated DC bus adopts a medium-voltage DC bus structure with a voltage level of 750V to 10kV.

[0019] Furthermore, under low-load operating conditions, the SOFC power generation module provides the basic power output of the ship's integrated energy system, while the thermoelectric power generation module uses the waste heat from the SOFC exhaust gas for auxiliary power generation, and the energy storage module is charged. Under medium-load operating conditions, the SOFC power generation module and the thermoelectric power generation module provide the load output, and the energy storage module is in a charge-discharge balance. Under high-dynamic load operating conditions, the energy storage module performs rapid power compensation, and the SOFC power generation module, the thermoelectric power generation module, and the energy storage module jointly provide the load output.

[0020] A control method for a ship integrated energy system coupled with a solid oxide fuel cell and thermoelectric power generation includes the following steps: Step S1: Real-time acquisition of SOFC output power, SOFC exhaust gas temperature, TEG temperature difference, energy storage SOC, and ship load power; Step S2: Identify the current operating condition based on the ship's navigation status, including port operating condition, cruise operating condition, icebreaking operating condition, and dynamic positioning operating condition; Step S3: Establish SOFC model, TEG model, energy storage model and load model, and predict the system operating status in the future prediction time domain based on the models; Step S4: Based on the Model Predictive Control (MPC) algorithm, with the objective functions of minimizing system fuel consumption and maximizing overall power generation efficiency, perform rolling optimization to solve for SOFC output power, TEG operating status, and energy storage charging and discharging power; Step S5: Determine whether the optimization result meets the preset operating constraints; if the constraints are met, output the optimal control quantity; if the constraints are not met, recalculate the MPC optimization iteration; the constraints include: ship load power balance constraint; SOFC safe operating temperature constraint; thermoelectric generator module temperature difference constraint; energy storage module SOC upper and lower limit constraint; DC bus voltage stability constraint. Step S6: Based on the output optimal control quantity, coordinate control is performed on the ship's integrated energy system. The coordinated control includes SOFC power setting, TEG operating point adjustment, and energy storage module charging and discharging strategy.

[0021] Compared with the prior art, the present invention has the following significant advantages: This invention relates to a shipboard integrated energy system coupled with a solid oxide fuel cell (SOFC) and thermoelectric power generation, and its control method. It solves the problems of low waste heat utilization, insufficient overall energy efficiency, and poor adaptability to dynamic operating conditions in existing shipboard energy systems. By utilizing the high-temperature exhaust gas of the SOFC to drive thermoelectric power generation, waste heat is reused, improving the overall energy utilization efficiency of the ship. The system employs a model predictive control algorithm to optimize power allocation according to different navigation conditions, exhibiting advantages such as high efficiency, low emissions, and high reliability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the SOFC-TEG integrated marine energy system of the present invention; Figure 2 The diagram shows the energy flow of a ship under different operating conditions, including: (a) port operating condition (low load), (b) cruising operating condition (medium load), and (c) icebreaking operating condition (high load). Figure 3 This is a flowchart of energy management based on model predictive control. Figure 4 The diagram shows the structure of the thermoelectric generator module, including: (a) a plan view (front view) of the TEG, and (b) a cross-sectional view (AA) of the TEG. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] As shown in the figure Figures 1 to 4 As shown, the present invention discloses a ship integrated energy system coupled with a solid oxide fuel cell and thermoelectric power generation, comprising a fuel supply system, an SOFC power generation module, a thermoelectric power generation module, a waste heat recovery heat exchange module, a ship integrated DC bus, an energy storage module, a DC / DC converter 1, a DC / DC converter 2, a DC / AC converter, an intelligent energy management and control module, a ship propulsion load, and a daily load.

[0025] The fuel supply system supplies natural gas, methanol, or other hydrogen-containing fuels to the SOFC power generation module; the SOFC power generation module converts the chemical energy of the fuel into electrical energy and generates high-temperature exhaust gas; the waste heat recovery heat exchange module is connected to the exhaust gas outlet of the SOFC power generation module to recover the heat energy in the high-temperature exhaust gas of the SOFC and form a high-temperature heat source for the thermoelectric power generation module; the thermoelectric power generation module utilizes the high-temperature heat output from the waste heat recovery heat exchange module and the low-temperature cold source to form a temperature difference, realizing thermoelectric power generation; the low-temperature cold source of the thermoelectric power generation module is seawater cooling medium; the SOFC power generation module... The module is connected to DC / DC converter 1, and the thermoelectric generator module is connected to DC / DC converter 2. Both DC / DC converter 1 and DC / DC converter 2 are connected to the ship's integrated DC bus. The energy storage module is connected to the ship's integrated DC bus for peak shaving, power regulation, and transient load compensation. The DC / AC converter is connected between the ship's integrated DC bus and the ship's propulsion load and daily load for supplying power to the AC load. The intelligent energy management and control module communicates with each functional module to realize system operation status monitoring, energy scheduling, and power coordination control.

[0026] The control method of the present invention includes the following steps: Step S1: Real-time acquisition of SOFC output power, SOFC exhaust gas temperature, TEG temperature difference, energy storage SOC, ship load power, etc.

[0027] Step S2: Identify the current operating condition based on the ship's navigation status, including port operating condition, cruise operating condition, icebreaking operating condition and dynamic positioning operating condition.

[0028] Step S3: Establish SOFC model, TEG model, energy storage model and load model, and predict the system operating status in the future prediction time domain based on the models; Step S4: Based on the Model Predictive Control (MPC) algorithm, with the objective functions of minimizing system fuel consumption and maximizing overall power generation efficiency, perform rolling optimization to solve for SOFC output power, TEG operating status, and energy storage charging and discharging power; Step S5: Determine whether the optimization result meets the preset operating constraints; when the constraints are met, output the optimal control quantity; when the constraints are not met, recalculate the MPC optimization iteration; the constraints include: ship load power balance constraints; SOFC safe operating temperature constraints; thermoelectric power generation module temperature difference constraints; energy storage module SOC upper and lower limit constraints; DC bus voltage stability constraints, etc.

[0029] Step S6: Based on the output optimal control quantity, coordinate the control of the ship's integrated energy system. The coordinated control includes SOFC power setting, TEG operating point adjustment, and energy storage module charging and discharging strategy.

[0030] Preferred SOFC power generation module includes a fuel reforming unit, an SOFC stack, an air supply unit, and an exhaust gas emission unit; wherein the SOFC stack operates at a temperature of 600–1000°C.

[0031] Preferably, the waste heat recovery heat exchange module adopts one or more of the following structures: plate heat exchanger, finned heat exchanger, or microchannel heat exchanger.

[0032] Preferred: Thermoelectric power generation module, such as Figure 4 As shown, it includes a top clamping plate 1, a high-temperature exhaust channel 2, a high-temperature side heat-conducting layer 3, a diffusion and heat-equalizing layer 4, a thermoelectric conversion module 5, a diffusion and heat-equalizing layer 6, a low-temperature side heat-conducting layer 7, a seawater channel 8, a bottom plate 9, etc.; wherein the thermoelectric power generation module has a thermoelectric power generation unit array arranged between the high-temperature side heat-conducting layer and the low-temperature side heat-conducting layer.

[0033] Preferably, the thermoelectric power generation unit in the thermoelectric power generation module is made of Bi2Te3-based, PbTe-based, Skutterudite-based, or semi-Hall materials.

[0034] Preferably, the low-temperature side seawater cooling system of the thermoelectric generator module includes a seawater pump, a cooling channel, and a flow regulating valve; seawater flows through the cooling channel to the cold end of the thermoelectric generator module to achieve continuous cooling.

[0035] Preferred: The energy storage module is a lithium battery pack, a supercapacitor pack, or a combination of both; used to provide transient power support under sudden load changes on ships.

[0036] Preferably, the intelligent energy management and control module includes a data acquisition unit, a status monitoring unit, a power distribution unit, and an optimization control unit; the optimization control unit performs comprehensive energy scheduling based on SOFC output power, thermoelectric power generation output power, energy storage state of charge, and ship load requirements.

[0037] Preferred configuration: The intelligent energy management and control module includes a data acquisition unit, a status monitoring unit, a power distribution unit, and an optimization control unit; the ship's integrated DC bus adopts a medium-voltage DC bus structure with a voltage level of 750V to 10kV.

[0038] Preferred configuration: Under low-load operating conditions, the SOFC power generation module provides basic power output, while the thermoelectric power generation module utilizes the waste heat from the SOFC exhaust gas for auxiliary power generation, and the energy storage module is charged. Under medium-load operating conditions, the SOFC power generation module and the thermoelectric power generation module provide load output, and the energy storage module is in charge-discharge balance. Under high-dynamic load operating conditions, the energy storage module provides rapid power compensation, and the SOFC power generation module, the thermoelectric power generation module, and the energy storage module jointly provide load output.

[0039] This embodiment is merely an exemplary description of the present invention and does not limit its scope of protection. Those skilled in the art can make partial changes to it, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A shipboard integrated energy system coupling a solid oxide fuel cell and thermoelectric power generation, characterized in that: It includes a fuel supply system, SOFC power generation module, thermoelectric power generation module, waste heat recovery heat exchange module, ship integrated DC bus, energy storage module, DC / DC converter 1, DC / DC converter 2, DC / AC converter, intelligent energy management and control module, ship propulsion load and daily load; The fuel supply system is connected to the SOFC power generation module and is used to supply natural gas, methanol or other hydrogen-containing fuels to the SOFC power generation module; The SOFC power generation module is used to convert the chemical energy of fuel into electrical energy and generate high-temperature exhaust gas. The waste heat recovery heat exchange module is connected to the exhaust gas outlet of the SOFC power generation module to recover the heat energy in the high-temperature exhaust gas of SOFC and form a high-temperature heat source for supplying the thermoelectric power generation module. The thermoelectric power generation module is connected to the waste heat recovery heat exchange module. It utilizes the temperature difference between the high-temperature heat output from the waste heat recovery heat exchange module and the low-temperature cold source to achieve thermoelectric power generation. The thermoelectric power generation module is connected to a seawater cooling system on its low-temperature side, and the cold source is seawater cooling medium. The SOFC power generation module is connected to DC / DC converter 1, the thermoelectric power generation module is connected to DC / DC converter 2, and both DC / DC converter 1 and DC / DC converter 2 are connected to the ship's integrated DC bus. The energy storage module is connected to the ship's integrated DC bus and is used for system peak shaving, power regulation, and transient load compensation. The DC / AC converter is connected between the ship's integrated DC bus and the ship's propulsion load and daily load, and is used to supply power to the AC load. The intelligent energy management and control module is communicatively connected to each functional module to realize system operation status monitoring, energy scheduling, and power coordination control.

2. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The SOFC power generation module includes a fuel reforming unit, an SOFC stack, an air supply unit, and an exhaust gas emission unit; wherein the SOFC stack operates at a temperature of 600–1000°C.

3. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The waste heat recovery heat exchange module adopts one or more combinations of plate heat exchangers, finned heat exchangers, or microchannel heat exchangers.

4. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The thermoelectric power generation module includes a top clamping plate, a high-temperature exhaust channel, a high-temperature side heat-conducting layer, a diffusion heat-equalizing layer, a thermoelectric conversion module, a low-temperature side heat-conducting layer, a seawater channel, and a bottom plate; the thermoelectric power generation unit array of the thermoelectric power generation module is disposed between the high-temperature side heat-conducting layer and the low-temperature side heat-conducting layer.

5. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The thermoelectric power generation unit in the thermoelectric power generation module is made of Bi2Te3-based, PbTe-based, Skutterudite-based, or semi-Hall materials.

6. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The seawater cooling system on the low-temperature side of the thermoelectric power generation module includes a seawater pump, a cooling channel, and a flow regulating valve; seawater flows through the cooling channel to the cold end of the thermoelectric power generation module to achieve continuous cooling.

7. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The energy storage module is a lithium battery pack, a supercapacitor pack, or a combination of both; it is used to provide transient power support under sudden load changes on ships.

8. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: The intelligent energy management and control module includes a data acquisition unit, a status monitoring unit, a power distribution unit, and an optimization control unit. The optimization control unit performs comprehensive energy scheduling based on SOFC output power, thermoelectric power generation output power, energy storage charge status, and ship load requirements. The ship's integrated DC bus adopts a medium-voltage DC bus structure with a voltage level of 750V to 10kV.

9. The integrated marine energy system coupled with a solid oxide fuel cell and thermoelectric power generation according to claim 1, characterized in that: Under low-load operating conditions, the integrated ship energy system provides basic power output from the SOFC power generation module, while the thermoelectric power generation module utilizes the waste heat from the SOFC exhaust gas for auxiliary power generation, and the energy storage module is charged. Under medium-load operating conditions, the SOFC power generation module and the thermoelectric power generation module provide load output, and the energy storage module is in a charge-discharge balance. Under high-dynamic load operating conditions, the energy storage module provides rapid power compensation, and the SOFC power generation module, the thermoelectric power generation module, and the energy storage module jointly provide load output.

10. A control method for a ship integrated energy system coupled with a solid oxide fuel cell and thermoelectric power generation as described in any one of claims 1-9, characterized in that, Includes the following steps: Step S1: Real-time acquisition of SOFC output power, SOFC exhaust gas temperature, TEG temperature difference, energy storage SOC, and ship load power; Step S2: Identify the current operating condition based on the ship's navigation status, including port operating condition, cruise operating condition, icebreaking operating condition, and dynamic positioning operating condition; Step S3: Establish SOFC model, TEG model, energy storage model and load model, and predict the system operating status in the future prediction time domain based on the models; Step S4: Based on the Model Predictive Control (MPC) algorithm, with the objective functions of minimizing system fuel consumption and maximizing overall power generation efficiency, perform rolling optimization to solve for SOFC output power, TEG operating status, and energy storage charging and discharging power; Step S5: Determine whether the optimization result meets the preset running constraints; When the constraints are met, the optimal control quantity is output; If the constraints are not met, repeat the MPC optimization iteration calculation. The constraints include: ship load power balance constraints; SOFC safe operating temperature constraints; thermoelectric power generation module temperature difference constraints; energy storage module SOC upper and lower limit constraints; and DC bus voltage stability constraints. Step S6: Based on the output optimal control quantity, coordinate control is performed on the ship's integrated energy system. The coordinated control includes SOFC power setting, TEG operating point adjustment, and energy storage module charging and discharging strategy.

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