CN-115714446-B - Improved distributed cooperative control method for shipborne hybrid energy storage system

Abstract

The invention discloses an improved distributed cooperative control method of a shipborne hybrid energy storage system, which comprises the following steps of obtaining actual current and voltage on a direct-current bus, obtaining current and voltage of an output port of a direct-current converter to obtain output power of the direct-current converter, respectively obtaining voltage output by a storage battery and a super capacitor based on a proportional droop control method and an integral droop control method, obtaining a charge state of the super capacitor based on the voltage output by the super capacitor, compensating a bus voltage regulating factor into the proportional droop control method to accelerate the recovery speed of the charge state of the super capacitor, obtaining an SoC dynamic regulating factor based on a novel SoC dynamic regulating algorithm to enable the storage battery to gradually realize SoC balance in a charging and discharging process without current phenomenon, realizing transient power distribution between the storage battery and the super capacitor, wherein a high-frequency part of load power change is automatically distributed to the super capacitor, and a low-frequency part of load power change is compensated by the battery.

Inventors

• ZHANG QINJIN
• ZHANG YU
• LIU YANCHENG
• Qu tengda
• HU ZHIYONG
• WU MING

Assignees

• 大连海事大学

Dates

Publication Date

20260508

Application Date

20221107

Claims (2)

1. 1. An improved distributed cooperative control method for a ship-borne hybrid energy storage system is characterized by comprising the following steps: acquiring actual current and voltage on a direct current bus; obtaining current and voltage of an output port of the direct-current converter to obtain output power of the direct-current converter; Comparing the actual current and the actual voltage on the direct current bus with rated current and rated voltage respectively to obtain comparison voltage and comparison current of the direct current bus, and respectively obtaining voltages output by the storage battery and the super capacitor based on a proportional droop control method and an integral droop control method; Obtaining the charge state of the super capacitor based on the voltage output by the super capacitor; Compensating the busbar voltage regulating factor into proportional droop control to accelerate the recovery speed of the super-capacitor state of charge; Based on the SoC dynamic regulation algorithm, a SoC dynamic regulation factor is obtained, so that the storage battery gradually realizes SoC equalization in the charge and discharge process, and no current phenomenon exists; the expression of the bus voltage regulating factor is as follows: (14) (15) (16) V th and V OBi are respectively a rated value of a direct current bus voltage and an actual output voltage of an ith storage battery converter, G v is a PI regulator, gi is a pinning gain, and is set to be 1 or 0 according to the actual situation of a ship micro-grid, when gi is set to be 1, the local storage battery is shown to increase output power, the recovery speed of the direct current bus voltage is accelerated, and when gi is set to be 0, the local storage battery cannot increase the output power for the recovery of the direct current bus voltage; the expression of the dynamic SoC regulating factor is as follows: (18) (19) (20) Wherein: i Is a SoC adjustment factor, C Bi and S avgi are respectively SoC and locally measured SoC average values of the i-th battery, i N i is the number of adjacent nodes of the node i, and a s is the uniformity gain of the average SoC.
2. 2. The apparatus of claim 1, wherein the means for improved distributed cooperative control of the onboard hybrid energy storage system comprises: the acquisition module I is used for acquiring actual current and voltage on the direct current bus; The acquisition module II acquires current and voltage of an output port of the direct-current converter to obtain output power of the direct-current converter; the comparison module is used for comparing the actual current and the actual voltage on the direct current bus with the rated current and the rated voltage respectively to obtain the comparison voltage and the comparison current of the direct current bus, The control module is used for comparing the voltage and the current of the direct current bus and respectively obtaining the output voltages of the storage battery and the super capacitor based on a proportional sagging control method and an integral sagging control method; The obtaining module is used for obtaining the charge state of the super capacitor based on the voltage output by the super capacitor; The compensation module is used for compensating the busbar voltage regulating factor into proportional droop control and accelerating the recovery speed of the super-capacitor state of charge; and the adjusting module is used for obtaining a SoC dynamic adjusting factor based on the SoC dynamic adjusting algorithm, so that the storage battery gradually realizes SoC equalization in the charging and discharging process and has no current phenomenon.

Description

Improved distributed cooperative control method for shipborne hybrid energy storage system Technical Field The invention belongs to the field of shipborne micro-grids, and relates to an improved shipborne hybrid energy storage system distributed cooperative control method. Background With the development progress of a direct-current power system, a double-electric ship taking a storage battery and a super capacitor as power is generated. Super-capacitors have a higher power density but a lower energy density. Lithium batteries have a higher energy density, but a lower power density. The hybrid energy storage system combines the advantages of the two systems together to ensure the transient power sharing required by the ship power system, realize the peak clipping and valley filling of bus voltage fluctuation, effectively reduce the emission of polluted gas, and is an important research direction for developing green shipping in the future. The control method of the hybrid energy storage system can be divided into three types according to the different dependence degree of the system on the communication network, and the first type is distributed control. Decentralized control does not rely on any communication infrastructure to improve system scalability. For example, document Frequency-coordinating virtual impedance for autonomous power management of DC microgrid [1] integrates a high-pass filter and a low-pass filter into a hybrid energy storage system, dividing the load power into high-Frequency and low-Frequency components. However, the distributed control is adopted, the control precision is not high, and the problem of over-charge and over-discharge possibly occurring when a plurality of groups of energy storage units are connected in parallel is not considered. The second type is centralized control, which is to collect the information of the whole system through a central controller and flexibly implement various control schemes. In document A model predictive control system for a hybrid battery-ultracapacitor power source [2], a control scheme based on model prediction is proposed, wherein a high-frequency part of load power is distributed to a super capacitor, and a battery responds to a low-frequency component, so that the service life of the battery can be effectively prolonged, but the method is complex to control and has higher communication requirements. The third type is distributed control, and the two control methods are analyzed, so that the accuracy of the distributed control is not high, and the voltage deviation of the direct current bus is easy to exceed the allowable range, which may damage the voltage sensitive load. Document "ASemi-Consensus Strategy Toward Multi-Functional Hybrid Energy Storage System in DC Microgrids"[3] describes a distributed control scheme based on proportional integral droop control, which achieves transient power distribution of the battery and super capacitor and restores the dc bus voltage to a nominal value, but when SoC equalization between batteries is achieved, a circulation phenomenon occurs. Meanwhile, due to the differences of production and use processes and storage conditions, each energy storage unit is easy to have the condition of SoC inconsistency, the mixed energy storage system can have a circulation phenomenon in the operation process, and when serious, part of the energy storage units can be withdrawn from operation, the service life of the system is influenced, and the stability of the ship direct-current micro-grid is reduced. Meanwhile, compared with a land direct current micro-grid, the ship direct current micro-grid is required to have higher stability due to complex and changeable loads of ship operation conditions, which means that a storage battery and a super capacitor are required to have higher SoC equalization speed and recovery speed. To solve the above problems, a new control method needs to be developed. Disclosure of Invention In order to solve the problems, the invention provides an improved distributed cooperative control method of a ship-borne hybrid energy storage system, which comprises the following steps: acquiring actual current and voltage on a direct current bus; obtaining current and voltage of an output port of the direct-current converter to obtain output power of the direct-current converter; Comparing the actual current and the actual voltage on the direct current bus with rated current and rated voltage respectively to obtain comparison voltage and comparison current of the direct current bus, and respectively obtaining voltages output by the storage battery and the super capacitor based on a proportional droop control method and an integral droop control method; Obtaining the charge state of the super capacitor based on the voltage output by the super capacitor; Compensating the busbar voltage regulating factor into proportional droop control to accelerate the recovery speed of the super-capacitor state of