Regenerative electric energy recovery and optimal utilization system and method for port electrical equipment

Abstract

The invention discloses a regenerative electric energy recovery and optimal utilization system and method for port electrical equipment, and belongs to the technical field of port energy recovery, and the system comprises a regenerative electric energy capturing unit, a bidirectional conversion unit, a hybrid energy storage unit, an intelligent energy management unit and a multi-element utilization unit. The high-power response speed and the high energy storage density are both considered, the adaptability problem of a single energy storage medium is solved, and the regeneration electric energy recovery efficiency is improved to 95% or above. An intelligent energy management strategy based on a fuzzy PID algorithm is constructed, dynamic distribution of regenerative electric energy in a three-level utilization path of equipment self consumption, auxiliary power supply and power grid feedback is achieved, and the method adapts to complex operation conditions of a shore bridge and load changes of a power grid. The bidirectional converter unit integrates harmonic suppression and power factor correction functions, the total harmonic distortion (THD) of electric energy fed back to a power grid is less than or equal to 3%, and impact pollution to the power grid is remarkably reduced.

Description

Regenerative Energy Recovery and Optimization System and Method for Port Electrical Equipment Technical Field

[0001] This invention relates to the field of port energy recovery technology, specifically to a system and method for the recovery and optimized utilization of regenerated electrical energy from port electrical equipment. Background Technology

[0002] Ports, as key nodes in land and water transportation, are important carriers of human civilization exchange and trade. Embedded at the confluence of coastlines, rivers, and lakes, they bear the core mission of connecting the interior and exterior, and linking the north and south. Geographically, high-quality ports often rely on natural deep-water coastlines, possessing natural conditions such as shelter from wind, ice-free conditions, and suitable water depth. With the assistance of artificial dredging, wharf construction, and other engineering optimizations, they form comprehensive hubs with loading, unloading, warehousing, and transshipment functions. Functionally, ports are the core hubs of the global supply chain. In container terminals, giant quay cranes, like steel giants, precisely grab containers, quickly transferring electronic products from Asia, machinery and equipment from Europe, and agricultural products from the Americas to the inland. Bulk cargo terminals handle industrial raw materials such as coal and iron ore, supporting the industrial lifeline of the regional economy. At the same time, passenger ports play an important role in cross-border tourism and inter-island commuting. Luxury cruise ships and high-speed passenger ships take off and land here, witnessing the departures and reunions of countless people.

[0003] Throughout history, ports have always been witnesses to the evolution of civilization. In ancient times, Quanzhou and Alexandria were the starting and ending points of the Maritime Silk Road. Silk, spices, and porcelain flowed through these ports, facilitating the collision and fusion of different civilizations. In modern times, ports have become the forefront of the Industrial Revolution, driving the rise of coastal cities such as Shanghai Port and New York Port. Today, they have developed into economic centers with dense populations and industrial clusters. As the core equipment for container loading and unloading, port quay cranes generate a large amount of regenerative electricity during the lowering of heavy objects and deceleration braking processes.

[0004] Although existing renewable energy recovery technologies have incorporated energy storage units, they still have significant drawbacks: First, the energy storage medium mostly uses a single lithium battery or capacitor, which is difficult to balance the requirements of high-power charging and discharging speeds and high energy storage density, resulting in insufficient adaptability; Second, energy management lacks intelligent control strategies, making it impossible to dynamically allocate renewable energy according to the operating conditions of the quay crane, the energy storage status, and the grid load; Third, the utilization of renewable energy is limited to single pathways, mostly confined to equipment self-consumption, failing to achieve efficient cascade utilization of surplus power. Therefore, those skilled in the art have provided a system and method for the recovery and optimized utilization of renewable energy in port electrical equipment to solve the problems mentioned in the background. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for the recovery and optimized utilization of regenerative energy in port electrical equipment, in order to address the significant shortcomings of existing regenerative energy recovery technologies mentioned in the background: First, the energy storage medium mostly uses a single lithium battery or capacitor, which is difficult to meet the requirements of high-power charging and discharging speed and high energy storage density, resulting in insufficient adaptability; Second, energy management lacks intelligent control strategies, making it impossible to dynamically allocate regenerative energy according to the operating conditions of the quay crane, the energy storage status, and the grid load; Third, the utilization of regenerative energy is limited to the self-consumption of equipment, failing to achieve the efficient cascade utilization of surplus power.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A system and method for the recovery and optimized utilization of regenerative electrical energy in port electrical equipment includes a regenerative energy capture unit, a bidirectional converter unit, a hybrid energy storage unit, an intelligent energy management unit, and a multi-utilization unit. The regenerative energy capture unit includes a hoisting motor, a speed sensor, a voltage monitoring module, and a rectifier and filter circuit. The intelligent energy management unit includes a central controller and an operating condition monitoring module. The multi-utilization unit includes a quay crane self-consumption circuit, a port auxiliary equipment power supply circuit, and a grid feedback interface.

[0008] As a further aspect of the present invention: the lifting motor is a variable frequency asynchronous motor, which can switch to power generation mode when the heavy object is lowered or decelerated; the bidirectional converter unit adopts a three-level bidirectional converter based on IGBT and integrates active rectification and inversion functions.

[0009] As a further embodiment of the present invention: the hybrid energy storage unit is composed of a carbon-based capacitor module and a lithium iron phosphate energy storage battery pack connected in parallel, and the carbon-based capacitor module is made of nano-scale activated carbon material, and the grid feedback interface is equipped with a harmonic filter.

[0010] A system and method for the recovery and optimized utilization of regenerative electrical energy from port electrical equipment, comprising the following steps:

[0011] S1: Regenerative Energy Capture Stage: When the hoisting mechanism of the quay crane performs the operation of lowering heavy objects or deceleration braking, the speed of the hoisting motor is higher than the synchronous speed, and it enters the power generation state to generate regenerative energy; when the voltage monitoring module detects that the voltage of the common DC bus is higher than the preset threshold (usually 1.1 times the rated voltage), it triggers the regenerative energy capture process, the rectifier filter circuit starts working, and the power output is stabilized.

[0012] S2: Energy Conversion and Storage Stage: The intelligent energy management unit calculates the regenerated power based on the signal collected by the speed sensor and dynamically allocates the energy storage path in conjunction with the real-time SOC value of the hybrid energy storage unit.

[0013] When the regeneration power is ≥500kW, the energy is preferentially absorbed through the carbon-based capacitor module to avoid a sudden voltage rise;

[0014] When the regenerative power is less than 500kW and the SOC of the energy storage battery is less than 80%, the electrical energy is stored in the energy storage battery pack via a bidirectional DC / DC converter.

[0015] When the energy storage battery SOC is ≥ 90% and the carbon-based capacitor module is fully charged, the surplus power distribution process is initiated.

[0016] S3: Intelligent Optimization Utilization Stage: The central controller formulates a three-level utilization strategy based on the quay crane operation plan, energy storage status, and grid load.

[0017] Primary utilization: During subsequent lifting operations of the quay crane, the hybrid energy storage unit releases electrical energy through the bidirectional converter unit to assist the power grid and reduce peak power load;

[0018] Secondary utilization: When the quay crane is in standby mode and the energy storage SOC is ≥60%, it outputs electrical energy to the power supply circuit of port auxiliary equipment to replace the power grid supply.

[0019] Level 3 utilization: When the hybrid energy storage unit is fully charged and the grid load is low (peak-valley electricity price difference ≥ 0.5 yuan / kWh), the surplus electricity is purified and fed back to the grid through the grid feedback interface to maximize the benefits.

[0020] S4: Safety Protection Phase: The system is equipped with overvoltage, overcurrent, overtemperature, and SOC protection mechanisms. When the common DC bus voltage exceeds 1.3 times the rated value, the bidirectional converter unit automatically cuts off; when the hybrid energy storage unit's SOC is ≤10%, it stops supplying power to the outside; both the carbon-based capacitor module and the energy storage battery pack are equipped with temperature monitoring devices, and the cooling system is activated when the temperature exceeds 60℃.

[0021] As a further aspect of the present invention:

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] The system and method for recycling and optimizing the regenerative electrical energy of the port's electrical equipment adopts a hybrid energy storage architecture of carbon-based capacitors and lithium iron phosphate batteries, which balances high power response speed and high energy storage density, solves the compatibility problem of a single energy storage medium, and improves the regenerative electrical energy recovery efficiency to over 95%.

[0024] A smart energy management strategy based on fuzzy PID algorithm is constructed to realize the dynamic allocation of renewable energy in the three-level utilization path of "equipment self-consumption - auxiliary power supply - grid feedback", which can adapt to the complex operating conditions of quay cranes and changes in grid load.

[0025] The bidirectional converter unit integrates harmonic suppression and power factor correction functions, and the total harmonic distortion (THD) of the power fed back to the grid is ≤3%, which significantly reduces the impact pollution on the power grid.

[0026] Expanding the application scenarios of renewable electricity and maximizing energy value through tiered utilization can increase annual energy saving rate by 25%-40% compared to traditional technologies and reduce annual carbon emissions. Attached Figure Description

[0027] Figure 1 is a system diagram of the system and method for the recycling and optimized utilization of regenerative electrical energy in port electrical equipment.

[0028] In the diagram: 1. Regenerative energy capture unit; 101. Lifting motor; 102. Speed ​​sensor; 103. Voltage monitoring module; 104. Rectifier and filter circuit; 2. Bidirectional converter unit; 3. Hybrid energy storage unit; 4. Intelligent energy management unit; 401. Central controller; 402. Operating condition monitoring module; 5. Multi-utilization unit; 501. Shore crane self-consumption circuit; 502. Port auxiliary equipment power supply circuit; 503. Grid feedback interface. Detailed Implementation

[0029] Please refer to Figure 1. In this embodiment of the invention, the system and method for the recovery and optimized utilization of regenerative electrical energy in port electrical equipment includes a regenerative energy capture unit 1, a bidirectional converter unit 2, a hybrid energy storage unit 3, an intelligent energy management unit 4, and a multi-functional utilization unit 5. The regenerative energy capture unit 1 includes a hoisting motor 101, a speed sensor 102, a voltage monitoring module 103, and a rectifier filter circuit 104. The intelligent energy management unit 4 includes a central controller 401 and a working condition monitoring module 402. The central controller 401 incorporates a fuzzy PID control algorithm and acquires the real-time operating status of the quay crane via a CAN bus. The system uses data on lifting / lowering / standby, regenerated power, energy storage unit SOC (State of Charge) value, and real-time grid load to achieve dynamic allocation and optimized scheduling of regenerated power. The multi-utilization unit 5 includes a quay crane self-consumption circuit 501, a port auxiliary equipment power supply circuit 502, and a grid feedback interface 503. The quay crane self-consumption circuit 501 provides power to the hoisting mechanism, trolley running mechanism, etc.; the port auxiliary equipment power supply circuit 502 provides power to lighting, monitoring, and cooling equipment, etc.; and the grid feedback interface 503 feeds back the surplus power to the grid after purification when the hybrid energy storage unit 3 is fully charged and the grid load is low.

[0030] The hoisting motor 101 is a variable frequency asynchronous motor that switches to power generation mode when lowering or decelerating the load. The bidirectional converter unit 2 uses a three-level bidirectional converter based on IGBTs and integrates active rectification and inversion functions. The rectifier side converts regenerated power into stable DC power through an SPWM control strategy. The inverter side can output AC power at different voltage levels according to load requirements. The conversion efficiency is not less than 96%, and it has harmonic suppression and power factor correction functions. The hybrid energy storage unit 3 is composed of a carbon-based capacitor module and a lithium iron phosphate energy storage battery pack connected in parallel. The carbon-based capacitor module uses nano-level activated carbon material, which can absorb short-term high-power regenerated power with a response time of ≤5ms, adapting to the high-frequency power fluctuations of the quay crane. The energy storage battery pack is responsible for medium- and long-term energy storage and provides continuous power supply support. The two are independently controlled by a bidirectional DC / DC converter to achieve complementary advantages. The grid feedback interface 503 is equipped with a harmonic filter.

[0031] A system and method for the recovery and optimized utilization of regenerative electrical energy from port electrical equipment, comprising the following steps:

[0032] S1: Regenerative Energy Capture Stage: When the hoisting mechanism of the quay crane performs the lowering of heavy objects or deceleration braking operation, the speed of the hoisting motor 101 is higher than the synchronous speed, and it enters the power generation state to generate regenerative energy; when the voltage monitoring module 103 detects that the voltage of the common DC bus is higher than the preset threshold, which is usually 1.1 times the rated voltage, it triggers the regenerative energy capture process, and the rectifier filter circuit 104 starts to work to stabilize the power output.

[0033] S2: Energy Conversion and Storage Stage: The intelligent energy management unit 4 calculates the regenerated power based on the signal collected by the speed sensor 102, and dynamically allocates the energy storage path in conjunction with the real-time SOC value of the hybrid energy storage unit 3.

[0034] When the regeneration power is ≥500kW, the energy is preferentially absorbed through the carbon-based capacitor module to avoid a sudden voltage rise;

[0035] When the regenerative power is less than 500kW and the SOC of the energy storage battery is less than 80%, the electrical energy is stored in the energy storage battery pack via a bidirectional DC / DC converter.

[0036] When the energy storage battery SOC is ≥ 90% and the carbon-based capacitor module is fully charged, the surplus power distribution process is initiated.

[0037] S3: Intelligent Optimization Utilization Phase: The central controller 401 formulates a three-level utilization strategy based on the quay crane operation plan, energy storage status, and grid load.

[0038] Primary utilization: During subsequent lifting operations of the quay crane, the hybrid energy storage unit 3 releases electrical energy through the bidirectional converter unit 2 to assist the power grid and reduce peak power load;

[0039] Secondary utilization: When the quay crane is in standby mode and the energy storage SOC is ≥60%, it outputs electrical energy to the port auxiliary equipment power supply circuit 502 to replace the power grid supply;

[0040] Level 3 utilization: When the hybrid energy storage unit 3 is fully charged and the peak-valley electricity price difference is ≥0.5 yuan / kWh, the surplus electricity is purified and fed back to the grid through the grid feedback interface 503 to maximize the benefits.

[0041] S4: Safety Protection Phase: The system is equipped with overvoltage, overcurrent, overtemperature, and SOC protection mechanisms. When the voltage of the common DC bus exceeds 1.3 times the rated value, the bidirectional converter unit 2 will automatically disconnect; when the SOC of the hybrid energy storage unit 3 is ≤10%, it will stop supplying power to the outside; both the carbon-based capacitor module and the energy storage battery pack are equipped with temperature monitoring devices, and the heat dissipation system will be activated when the temperature exceeds 60℃.

[0042] Example 1

[0043] Taking a 45-ton quayside container crane as the application object, the system parameters are configured as follows: the hoisting motor has a rated power of 630kW and a common DC bus rated voltage of 750V; the bidirectional converter unit has a rated capacity of 800kVA and a conversion efficiency of 96.5%; the carbon-based capacitor module has a capacity of 500F and the energy storage battery pack has a capacity of 200kWh; the intelligent energy management unit adopts a PLC controller with a sampling frequency of 100Hz.

[0044] In actual operation, when the quay crane lowers a 45-ton container, the lifting motor generates approximately 580kW of regenerative energy. When the voltage monitoring module detects that the DC bus voltage has risen to 825V, it triggers the capture process. The carbon-based capacitor module first absorbs 300kW of instantaneous power, and the remaining 280kW of energy is stored in the energy storage battery pack. When the quay crane subsequently lifts a container of the same weight, the hybrid energy storage unit releases 420kW of energy to assist in power supply, reducing the grid power load by 66.7%. During standby periods, it supplies power to the port lighting system, saving an average of 120kWh of grid electricity per day. During off-peak periods each month, it feeds back approximately 3000kWh of surplus electricity, generating additional revenue. Tests show that the system operates stably, with a comprehensive utilization rate of 95.2% for regenerative energy, annual energy savings of approximately 78,000 yuan, and an annual reduction of 55 tons of carbon emissions.

[0045] Example 2

[0046] In multi-quay crane cluster operations, multiple systems are networked through the port energy management platform to achieve cross-equipment scheduling of renewable energy. When the No. 1 quay crane generates renewable energy and its own energy storage is fully charged, the intelligent energy management unit distributes the surplus power to the No. 2 quay crane, which is in the hoisting operation state, through the platform to achieve energy complementarity of the cluster, further reduce the overall grid dependence, and increase the overall energy saving rate of the cluster to 42%.

[0047] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of the equivalent elements of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A system and method for the recovery and optimized utilization of regenerative electrical energy in port electrical equipment, characterized in that, The system includes a regenerative energy capture unit (1), a bidirectional converter unit (2), a hybrid energy storage unit (3), an intelligent energy management unit (4), and a multi-functional utilization unit (5). The regenerative energy capture unit (1) includes a hoisting motor (101), a speed sensor (102), a voltage monitoring module (103), and a rectifier filter circuit (104). The intelligent energy management unit (4) includes a central controller (401) and a working condition monitoring module (402). The multi-functional utilization unit (5) includes a quay crane self-consumption circuit (501), a port auxiliary equipment power supply circuit (502), and a grid feedback interface (503).

2. The system and method for regenerating and optimizing the use of electrical energy in port electrical equipment according to claim 1, characterized in that, The hoisting motor (101) is a variable frequency asynchronous motor, which can switch to power generation mode when the heavy object is lowered or decelerated. The bidirectional converter unit (2) adopts a three-level bidirectional converter based on IGBT and integrates active rectification and inversion functions.

3. The system and method for regenerating and optimizing the utilization of electrical energy in port electrical equipment according to claim 1, characterized in that, The hybrid energy storage unit (3) is composed of a carbon-based capacitor module and a lithium iron phosphate energy storage battery pack connected in parallel, and the carbon-based capacitor module uses nano-level activated carbon material. The grid feedback interface (503) is equipped with a harmonic filter.

4. The system and method for recycling and optimizing the use of regenerative electrical energy in port electrical equipment according to claim 1 includes the following steps: S1: Regenerative electrical energy capture stage: When the hoisting mechanism of the quay crane performs the operation of lowering heavy objects or deceleration braking, the speed of the hoisting motor (101) is higher than the synchronous speed, and it enters the power generation state to generate regenerative electrical energy; when the voltage monitoring module (103) detects that the voltage of the common DC bus is higher than the preset threshold (usually 1.1 times the rated voltage), it triggers the regenerative electrical energy capture process, and the rectifier filter circuit (104) starts working to stabilize the electrical energy output. S2: Energy Conversion and Storage Stage: The intelligent energy management unit (4) calculates the regenerated power based on the signal collected by the speed sensor (102) and dynamically allocates the energy storage path in conjunction with the real-time SOC value of the hybrid energy storage unit (3): When the regenerated power is ≥500kW, the energy is absorbed through the carbon-based capacitor module first to avoid voltage surge; when the regenerated power is <500kW and the energy storage battery SOC is <80%, the energy is stored in the energy storage battery pack through the bidirectional DC / DC converter; when the energy storage battery SOC is ≥90% and the carbon-based capacitor module is fully charged, the surplus power allocation process is started. S3: Intelligent Optimization Utilization Stage: The central controller (401) formulates a three-level utilization strategy based on the quay crane operation plan, energy storage status, and grid load: Level 1 utilization: During subsequent quay crane lifting operations, the hybrid energy storage unit (3) releases electrical energy through the bidirectional converter unit (2) to assist the grid power supply and reduce peak power load; Level 2 utilization: When the quay crane is in standby mode and the energy storage SOC ≥ 60%, it outputs electrical energy to the port auxiliary equipment power supply circuit (502) to replace the grid power supply; Level 3 utilization: When the hybrid energy storage unit (3) is fully charged and the grid load is low (peak-valley electricity price difference ≥ 0.5 yuan / kWh), it feeds back the surplus electricity to the grid after purification through the grid feedback interface (503) to maximize revenue. S4: Safety Protection Stage: The system is equipped with overvoltage, overcurrent, overtemperature, and SOC protection mechanisms. When the voltage of the common DC bus exceeds 1.3 times the rated value, the bidirectional converter unit (2) is automatically cut off; when the hybrid energy storage unit 3SOC≤10%, it stops supplying power to the outside; both the carbon-based capacitor module and the energy storage battery pack are equipped with temperature monitoring devices, and the heat dissipation system is activated when the temperature exceeds 60℃.

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