Energy-saving optimization control method and system for hybrid energy of a ship

Abstract

The application provides a ship hybrid energy-saving optimization control method and system, which is applied to the ship propulsion control technical field. The voltage ripple period is extracted, the physical mapping relationship between the shaft frequency and the blade frequency is used to determine the cycle interval boundary value, the voltage ripple period is divided into three intervals of high frequency, medium frequency and low frequency, and then the different amplitude adjustment constraints in the preset cycle adjustment strategy are matched. The insufficient high frequency suppression or slow low frequency response caused by the unified amplitude limitation is avoided. The dynamic response and energy-saving effect of the propulsion system are considered while suppressing the load disturbance and improving the power quality. In addition, the phase adjustment direction and the danger degree of the disturbance phase are accurately matched, the power response lag or resonance deterioration caused by blind adjustment is avoided, the mechanical resonance risk is effectively suppressed, the control responsiveness of the propulsion system is ensured, and the safety hidden danger caused by the phase-resonance coupling in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of ship propulsion control technology, and in particular to an energy-saving optimization control method and system for ship hybrid energy. Background Technology

[0002] With the increasing demands for energy conservation and emission reduction in the global shipping industry, hybrid propulsion systems (comprising generators, energy storage units, and propulsion motors) are widely used due to their ability to optimize energy allocation and improve fuel economy. During ship propulsion, the propeller experiences periodic load disturbances due to factors such as uneven wake field, the periodic passage of blades through the stern, and changes in sea state. These disturbances are transmitted to the DC bus via the propulsion motor, causing voltage ripple and directly affecting the power quality, energy efficiency, and mechanical lifespan of the hybrid propulsion system. Therefore, designing a propulsion motor power control method that balances energy optimization and operational safety, considering the periodic disturbance characteristics of the propeller load, has become an important research direction in the field of ship hybrid propulsion systems.

[0003] In existing technologies, passive suppression methods based on filtering or energy management strategies based on fixed thresholds are commonly used to address periodic disturbances in propeller loads. Filtering-based methods use low-pass filters or notch filters to remove bus voltage ripple, smoothing the propulsion motor's power command and reducing the impact on the energy storage unit. Fixed-threshold energy management strategies set several thresholds based on the amplitude of the bus voltage or power; when the detected value exceeds the threshold, the propulsion power or energy storage charging / discharging power is adjusted to maintain system stability. Furthermore, some existing technologies compensate for the propulsion power command by introducing speed feedback or power feedforward into the control system to suppress the effects of load disturbances.

[0004] However, in existing technologies, voltage ripple is simply treated as an interference signal that needs to be filtered out. The propeller load disturbance characteristics contained in the ripple are not utilized, and differentiated amplitude adjustment cannot be implemented based on the correlation between the disturbance frequency and the propeller physical characteristics. This results in a uniform power limiting strategy being used in different disturbance frequency ranges, making it difficult to achieve optimal energy-saving effects while ensuring system stability. At the same time, existing technologies do not consider the mechanical resonance characteristics of the propeller shaft system when adjusting propulsion power. When the load disturbance frequency is close to the shaft system's natural frequency, if the power command is still adjusted in the conventional way, mechanical resonance may be aggravated due to improper power output timing, causing shaft fatigue damage or even structural damage, affecting the operational safety of the propulsion system. Summary of the Invention

[0005] This application provides an energy-saving optimization control method and system for ship hybrid energy systems. The core of this method lies in: acquiring the shaft frequency and blade frequency signals of the propeller; determining the boundary values ​​of the periodic interval using the physical relationship between the reference rotational frequency and the blade passing frequency; classifying the voltage ripple period into intervals; and applying differentiated amplitude adjustment constraints based on the different intervals of the disturbance frequency to achieve refined control of the propulsion power command. Simultaneously, by performing interval mapping processing on the voltage ripple phase data and combining it with preset mechanical resonance frequency interval information, when the disturbance frequency falls into the resonance danger zone, determining the phase adjustment direction based on the phase interval information, and adjusting the output timing of the propulsion power command to avoid the risk of mechanical resonance. Through the synergistic effect of amplitude and phase adjustment, this application effectively ensures the operational safety of the propulsion shaft system while suppressing the impact of periodic propeller load disturbances on the hybrid energy system and achieving energy-saving optimization.

[0006] To achieve the above objectives, this application adopts the following technical solution: This application provides an energy-saving optimization control method for ship hybrid energy, the method including: Acquire voltage ripple period, voltage ripple phase data, and propulsion power reference command caused by periodic changes in propeller load; Acquire the shaft frequency signal, blade frequency signal, and preset mechanical resonance frequency range information of the propeller; Based on the shaft frequency signal and the blade frequency signal, determine the boundary values ​​of the period interval; Based on the boundary value of the period interval, the voltage ripple period is determined to obtain the period interval information where the voltage ripple period is located; Based on the period interval information and combined with the preset period adjustment strategy, the amplitude adjustment constraint of the propulsion power reference command is determined. The voltage ripple phase data is subjected to interval mapping processing to map the voltage ripple phase data to a preset phase interval, thereby obtaining the phase interval information where the voltage ripple phase data is located. Based on the phase interval information, combined with the preset phase adjustment strategy and the preset mechanical resonance frequency interval information, the phase adjustment direction of the propulsion power reference command is determined; Based on the amplitude adjustment constraint and the phase adjustment direction, the propulsion power reference command is modified to generate a propulsion motor power command; Output the propulsion motor power command to control the propulsion motor to drive the propeller.

[0007] An energy-saving optimization control system for ship hybrid energy, the system comprising: Acquisition module, processing module, instruction generation module, and output module; The acquisition module is used to acquire voltage ripple period, voltage ripple phase data and propulsion power reference command caused by the periodic change of propeller load, as well as to acquire shaft frequency signal, blade frequency signal and preset mechanical resonance frequency range information of the propeller. The processing module includes a period processing unit and a phase processing unit. The period processing unit is used to determine the period interval boundary value based on the shaft frequency signal and the blade frequency signal, and to perform interval determination on the voltage ripple period according to the period interval boundary value to obtain the period interval information where the voltage ripple period is located. Based on the period interval information and a preset period adjustment strategy, the amplitude adjustment constraint of the propulsion power reference command is determined. The phase processing unit is used to perform interval mapping processing on the voltage ripple phase data, map the voltage ripple phase data to a preset phase interval, obtain the phase interval information where the voltage ripple phase data is located, and determine the phase adjustment direction of the propulsion power reference command based on the phase interval information combined with a preset phase adjustment strategy and the preset mechanical resonance frequency interval information. The instruction generation module is used to modify the propulsion power reference instruction based on the amplitude adjustment constraint and the phase adjustment direction to generate a propulsion motor power instruction. The output module is used to output the power command of the propulsion motor and control the propulsion motor to drive the propeller.

[0008] As can be seen from the above technical solution, this application has the following beneficial effects: 1. This application extracts the voltage ripple period and uses the physical mapping relationship between shaft frequency and blade frequency to determine the boundary value of the period interval, dividing the voltage ripple period into three intervals: high frequency, medium frequency, and low frequency. Then, it matches different amplitude adjustment constraints in the preset period adjustment strategy, thereby avoiding insufficient high-frequency suppression or sluggish low-frequency response caused by uniform amplitude limitation. This allows the dynamic response and energy-saving effect of the propulsion system to be taken into account while suppressing load disturbances and improving power quality. It solves the drawback of the prior art that cannot dynamically adjust the amplitude constraint according to the disturbance frequency.

[0009] 2. This application maps voltage ripple phase data to a preset phase range and pre-calibrates dangerous and safe phase windows based on shaft dynamics tests. When the disturbance frequency falls into the resonance range, only the phase of the dangerous window is delayed or advanced, so that the power output is offset from the phase point of resonance aggravation, while the phase of the safe window remains unchanged. Moreover, the phase adjustment direction is precisely matched with the degree of danger of the disturbance phase, avoiding blind adjustment that causes power response lag or resonance deterioration. Thus, while effectively suppressing the risk of mechanical resonance, the control responsiveness of the propulsion system is guaranteed, solving the safety hazards caused by the failure to consider phase-resonance coupling in the prior art.

[0010] 3. This application achieves synergistic optimization of load disturbance suppression and mechanical resonance avoidance through an energy-saving optimization control system for ship hybrid energy, effectively improving the energy efficiency, operational stability and shafting safety of the ship hybrid energy system. Attached Figure Description

[0011] The present application will be further described below with reference to the accompanying drawings.

[0012] Figure 1 A flowchart of an energy-saving optimization control method for ship hybrid energy provided in this application; Figure 2 An example diagram of an energy-saving optimization control system for ship hybrid energy provided in this application. Detailed Implementation

[0013] The terms "first," "second," and "third," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0014] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0015] Research has revealed that in existing technologies, voltage ripple is simply treated as interference signals that need to be filtered out. The propeller load disturbance characteristics contained within the ripple are not utilized, and differentiated amplitude adjustments cannot be implemented based on the correlation between disturbance frequency and propeller physical characteristics. This results in a uniform power limiting strategy being used across different disturbance frequency ranges, making it difficult to achieve optimal energy-saving effects while ensuring system stability. Furthermore, existing technologies do not consider the mechanical resonance characteristics of the propeller shaft system when adjusting propulsion power. When the load disturbance frequency approaches the shaft system's natural frequency, adjusting the power command in the conventional manner may exacerbate mechanical resonance due to inappropriate power output timing, causing shaft fatigue damage or even structural damage, thus affecting the operational safety of the propulsion system.

[0016] Example 1: To address the above problems, this application provides an energy-saving optimization control method for ship hybrid energy. Please refer to [link / reference]. Figure 1 .

[0017] S1 acquires voltage ripple period, voltage ripple phase data, propulsion power reference command, propeller shaft frequency signal, blade frequency signal, and preset mechanical resonance frequency range information.

[0018] Acquire voltage ripple period, voltage ripple phase data, and propulsion power reference commands caused by periodic changes in propeller load.

[0019] Specifically, the DC bus voltage signal is acquired in real time by a voltage sensor, and a propulsion power reference command is obtained from the ship's hybrid energy control system. The propulsion power reference command is used to characterize the target output power of the propulsion motor. The acquired bus voltage signal is processed to extract the ripple component. The AC ripple component is separated from the bus voltage signal by a filtering separation method to obtain the voltage ripple signal. Feature extraction is performed on the voltage ripple signal. The periodic variation law of the voltage ripple signal is identified by a zero-crossing detection method, and the time interval between two adjacent cycle starting points is extracted to obtain the voltage ripple period. The starting phase angle of the voltage ripple signal within the period is extracted by a waveform matching method to obtain the voltage ripple phase data.

[0020] Simultaneously, the shaft frequency signal, blade frequency signal, and preset mechanical resonance frequency range information of the propeller are acquired.

[0021] Specifically, a rotational speed sensor installed on the propeller shaft system collects the shaft rotational speed signal, and performs spectral analysis on the shaft rotational speed signal to obtain the shaft frequency signal, which is used to characterize the rotational frequency of the propeller; a water pressure sensor installed near the propeller collects the blade passing signal in real time, and performs spectral analysis on the blade passing signal to obtain the blade frequency signal, which is used to characterize the frequency at which the propeller blades periodically pass through the stern region; preset mechanical resonance frequency range information is read from the parameter database of the ship propulsion system. The preset mechanical resonance frequency range information includes the shaft torsional resonance frequency range and the bending resonance frequency range, which is used to subsequently determine whether the load disturbance frequency is close to the mechanical resonance point.

[0022] Through the above processing, voltage ripple period, voltage ripple phase data, propulsion power reference command, shaft frequency signal, blade frequency signal, and preset mechanical resonance frequency range information were obtained, providing a data foundation for subsequent differential amplitude and phase adjustment based on propeller physical characteristics.

[0023] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: Bus voltage signal refers to the real-time measured voltage on the DC bus of a ship. This signal contains a DC component and an AC ripple component, where the AC ripple component is caused by periodic disturbances of the propeller load.

[0024] The propulsion power reference command refers to the raw command signal generated by the ship's hybrid energy control system to indicate the target output power of the propulsion motor, which includes the target power value and output timing information.

[0025] Ripple component extraction processing refers to the process of separating the AC ripple component from the bus voltage signal to obtain the voltage ripple signal that reflects the characteristics of propeller load disturbance. It is a conventional technique in the field of signal processing.

[0026] Voltage ripple signal refers to the AC ripple component extracted from the bus voltage signal. Its period and phase variation are directly related to the propeller load disturbance.

[0027] Voltage ripple period refers to the time interval between the starting points of two adjacent periods of the voltage ripple signal, and is used to characterize the frequency characteristics of propeller load disturbance.

[0028] Voltage ripple phase data refers to the starting phase angle of the voltage ripple signal within one cycle, used to characterize the phase characteristics of load disturbance.

[0029] Shaft speed signal refers to the real-time data of propeller shaft rotation speed collected by a speed sensor, which is used to extract shaft frequency signal.

[0030] Shaft frequency signal refers to the rotational frequency of the propeller shaft system, that is, the number of revolutions the propeller makes per second. It is obtained by spectrum analysis of the shaft speed signal and is used to characterize the physical rotational characteristics of the propeller.

[0031] The blade passage signal refers to the signal collected by the water pressure sensor as the propeller blades periodically pass through the stern area of ​​the ship, which is used to extract the blade frequency signal.

[0032] The blade frequency signal refers to the frequency at which the propeller blades pass through the stern region of the ship. It is equal to the shaft frequency multiplied by the number of blades and is obtained by spectral analysis of the blade passing signal. It is used to characterize the blade passing characteristics of the propeller.

[0033] The preset mechanical resonance frequency range information refers to the shaft torsional resonance frequency range and bending resonance frequency range stored in advance in the ship propulsion system, which is used to determine whether the load disturbance frequency is close to the mechanical resonance point.

[0034] In some possible implementations, the voltage ripple actually contains complete characteristic information of the propeller load disturbance, including the disturbance frequency (corresponding to the voltage ripple period) and the disturbance phase (corresponding to the voltage ripple phase data). This information has a definite correlation with the physical characteristics of the propeller (shaft frequency, blade frequency). If these correlations can be utilized, differentiated amplitude adjustments can be implemented according to the range of the disturbance frequency, and the timing of power output can be optimized by combining mechanical resonance characteristics, thereby achieving energy-saving optimization while suppressing load disturbances.

[0035] This step provides the data foundation for subsequent differentiated control. When processing voltage ripple, since the bus voltage contains both DC and AC ripple components, filtering and separation methods (such as high-pass filtering and notch filtering) are needed to extract the AC ripple component and obtain a pure voltage ripple signal. This signal removes DC offset and power frequency interference and can truly reflect the periodic variation law of propeller load disturbance.

[0036] During feature extraction, the voltage ripple period can be obtained through the zero-crossing detection method, that is, detecting the time point when the voltage ripple signal waveform crosses zero from the negative or positive direction, and the time interval between two adjacent zero-crossing points is the voltage ripple period; the voltage ripple phase data is obtained through the waveform matching method, that is, matching the voltage ripple signal with a standard sine waveform to determine its starting phase angle within the period.

[0037] When acquiring shaft frequency and blade frequency signals, the shaft frequency signal can be obtained by performing spectral analysis on the shaft rotation speed signal; the blade frequency signal can be obtained by performing spectral analysis on the blade passage signal.

[0038] Furthermore, there is a definite mapping relationship between the shaft frequency signal and the blade frequency signal and the voltage ripple period; that is, the voltage ripple period is usually between the shaft frequency period (the reciprocal of the shaft frequency) and the blade frequency period (the reciprocal of the blade frequency). Therefore, the shaft frequency signal and the blade frequency signal can be used as boundary value references for subsequent determination of the voltage ripple period range.

[0039] The data obtained in this step enables the system to extract disturbance characteristic information related to the propeller's physical characteristics from the original bus voltage signal, providing accurate input for subsequent steps and solving the problem in the prior art of simply treating voltage ripple as an interference signal and discarding the load disturbance characteristic information it contains.

[0040] S2, based on the shaft frequency signal and the blade frequency signal, determines the boundary value of the period interval, and according to the boundary value of the period interval, determines the period interval of the voltage ripple period to obtain the period interval information where the voltage ripple period is located.

[0041] The shaft frequency signal is analyzed to obtain the reference rotational frequency, and the blade frequency signal is analyzed to obtain the blade passage frequency. The reference rotational frequency is used as the first reference frequency, and based on the correspondence between period and frequency, a first period value corresponding to the first reference frequency is determined. The blade passage frequency is used as the second reference frequency, and based on the correspondence between period and frequency, a second period value corresponding to the second reference frequency is determined. The first period value and the second period value are compared, and based on the correspondence between period and frequency, the first period value is found to be greater than the second period value. The first period value and the second period value are defined as the boundary values ​​of the period intervals, where the first period value is the boundary value of the maximum period interval, and the second period value is the boundary value of the minimum period interval.

[0042] The voltage ripple period is compared with the boundary value of the period interval to obtain the first comparison result, and the first comparison result is determined as the period interval information where the voltage ripple period is located.

[0043] Specifically, the voltage ripple period is compared with the second period value. When the voltage ripple period is less than the second period value, the voltage ripple period is in the first period interval, and the first period interval is determined as the first comparison result. When the voltage ripple period is greater than or equal to the second period value and less than or equal to the first period value, the voltage ripple period is in the second period interval, and the second period interval is determined as the first comparison result. When the voltage ripple period is greater than the first period value, the voltage ripple period is in the third period interval, and the third period interval is determined as the first comparison result.

[0044] Through the above processing, by utilizing the physical correlation between shaft frequency signal, blade frequency signal and voltage ripple period, the boundary value of the period interval with shaft frequency period as the upper limit and blade frequency period as the lower limit was determined, and the voltage ripple period was divided into the first period interval, the second period interval and the third period interval, thus obtaining the period interval information of the voltage ripple period, which provides a basis for subsequently determining the amplitude adjustment constraint of the propulsion power reference command.

[0045] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: The reference rotational frequency refers to the rotational frequency of the propeller shaft system extracted from the shaft frequency signal, that is, the number of revolutions the propeller makes per second, which is used to determine the period value corresponding to the shaft frequency.

[0046] The blade passage frequency refers to the frequency at which the propeller blades pass through the stern region, extracted from the blade frequency signal. It is equal to the reference rotational frequency multiplied by the number of blades and is used to determine the period value corresponding to the blade frequency.

[0047] The correspondence between period and frequency refers to the physical relationship that period and frequency are reciprocals of each other, that is, period equals the reciprocal of frequency, and is used to convert frequency value into period value.

[0048] The first period value refers to the period value corresponding to the reference rotation frequency, that is, the value of the shaft frequency period, which is the larger value among the boundary values ​​of the period interval.

[0049] The second period value refers to the period value corresponding to the frequency of the blade passage, that is, the value of the leaf frequency period, which is the smaller value among the boundary values ​​of the period interval.

[0050] The period interval boundary value refers to the interval boundary formed by the first period value and the second period value, which is used to divide the voltage ripple period into different intervals. The first period value is the boundary value of the maximum period interval, and the second period value is the boundary value of the minimum period interval.

[0051] The maximum period interval boundary value refers to the boundary value with the larger value among the period interval boundary values, which corresponds to the shaft frequency period and serves as the upper limit benchmark for determining the voltage ripple period interval.

[0052] The minimum period interval boundary value refers to the boundary value with the smaller value among the period interval boundary values, corresponding to the blade frequency period, and serves as the lower limit benchmark for determining the voltage ripple period interval.

[0053] The first comparison result refers to the interval assignment result obtained by comparing the voltage ripple period with the boundary value of the period interval, including the first period interval, the second period interval, or the third period interval.

[0054] The first period interval refers to the period interval where the voltage ripple period is less than the second period value.

[0055] The second period interval refers to the period interval where the voltage ripple period is greater than or equal to the second period value and less than or equal to the first period value.

[0056] The third period interval refers to the period interval where the voltage ripple period is greater than the first period value.

[0057] Period interval information refers to the period interval to which the voltage ripple period belongs. It is used to compare with the preset period adjustment strategy to determine the corresponding amplitude adjustment constraint.

[0058] In some possible implementations, the voltage ripple is caused by the periodic variation of the propeller load, and the frequency of the propeller load variation is between the shaft frequency and the blade frequency. That is, the shaft frequency corresponds to the disturbance frequency of the propeller per revolution, and the blade frequency corresponds to the disturbance frequency of each blade passing by.

[0059] Therefore, the theoretical range of the voltage ripple period should be between the shaft frequency period (larger value) and the blade frequency period (smaller value). Using this physical relationship, the effective range boundary of the voltage ripple period can be determined by the shaft frequency and the blade frequency.

[0060] This step extracts the reference rotational frequency and blade passage frequency from the shaft frequency and blade frequency signals, respectively. Utilizing the reciprocal relationship between period and frequency, it calculates the first period value corresponding to the shaft frequency and the second period value corresponding to the blade frequency. Since frequency and period are inversely proportional, and the reference rotational frequency is less than the blade passage frequency, the first period value is greater than the second period value; that is, the shaft frequency period is greater than the blade frequency period. The first period value is used as the boundary value of the maximum period interval, and the second period value is used as the boundary value of the minimum period interval, forming a physically defined period interval with the blade frequency period as the lower limit and the shaft frequency period as the upper limit.

[0061] Based on this, by comparing the voltage ripple period with these two boundary values, the range of the voltage ripple period can be determined.

[0062] For example, suppose the propeller's shaft frequency period (first period value) is 0.5 seconds and the blade frequency period (second period value) is 0.125 seconds. If the currently detected voltage ripple period is 0.2 seconds, since 0.2 seconds is greater than 0.125 seconds and less than 0.5 seconds, the voltage ripple period is in the second period range; if the voltage ripple period is 0.1 seconds, which is less than 0.125 seconds, it is in the first period range; and if the voltage ripple period is 0.6 seconds, which is greater than 0.5 seconds, it is in the third period range.

[0063] The period interval information determined in this step will serve as the input for determining the amplitude adjustment constraint of the propulsion power reference command in subsequent S3, enabling the system to adopt differentiated amplitude adjustment strategies according to different intervals of the voltage ripple period, thereby providing a basis for subsequent targeted power control.

[0064] S3, based on period interval information and combined with a preset period adjustment strategy, determines the amplitude adjustment constraint of the propulsion power reference command.

[0065] A preset periodic adjustment strategy is obtained, in which the first, second, and third period intervals correspond to different amplitude adjustment constraints. The period interval information is compared with the preset periodic adjustment strategy to determine the target strategy corresponding to the period interval information within the preset periodic adjustment strategy, and the target strategy is determined as the amplitude adjustment constraint of the propulsion power reference command.

[0066] Specifically, when the period interval information is the first period interval, the amplitude adjustment constraint is the first amplitude adjustment constraint; when the period interval information is the second period interval, the amplitude adjustment constraint is the second amplitude adjustment constraint; and when the period interval information is the third period interval, the amplitude adjustment constraint is the third amplitude adjustment constraint. The amplitude adjustment constraint is used to limit the range of power amplitude variation of the propulsion power reference command to avoid drastic power fluctuations caused by load disturbances.

[0067] Through the above processing, based on the period range in which the voltage ripple period is located, the corresponding amplitude adjustment constraint is matched from the preset period adjustment strategy, providing an amplitude limit basis for subsequent modification of the propulsion power reference command.

[0068] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: The preset cycle adjustment strategy refers to the pre-defined correspondence between different cycle intervals and different amplitude adjustment constraints, which is used to determine the amplitude limitation method of the propulsion power reference command based on the interval where the voltage ripple cycle is located.

[0069] The first amplitude adjustment constraint refers to the amplitude limitation rule corresponding to the first cycle interval, which is used to limit the power amplitude of the propulsion power reference command accordingly.

[0070] The second amplitude adjustment constraint refers to the amplitude limitation rule corresponding to the second period interval, which is used to limit the power amplitude of the propulsion power reference command accordingly.

[0071] The third amplitude adjustment constraint refers to the amplitude limitation rule corresponding to the third cycle interval, which is used to limit the power amplitude of the propulsion power reference command accordingly.

[0072] Amplitude adjustment constraints refer to rules used to limit the range of variation in the amplitude of propulsion power reference command power, including parameters such as upper limit of amplitude, lower limit of amplitude, or rate of change limit.

[0073] In some possible implementations, load disturbances of different frequencies have varying impacts on the power demand of the propulsion motor. High-frequency disturbances (corresponding to the first cycle interval) are typically caused by blade passage, resulting in significant fluctuations but relatively low energy; therefore, larger amplitude constraints are needed to prevent frequent and large changes in power command. Mid-frequency disturbances (corresponding to the second cycle interval), falling between the shaft frequency and blade frequency, are conventional propeller rotation disturbances, requiring only moderate amplitude adjustment. Low-frequency disturbances (corresponding to the third cycle interval) are usually caused by slow factors such as changes in sea state; amplitude constraints can be smaller or nonexistent to maintain the responsiveness of the propulsion power. Therefore, it is necessary to select the appropriate amplitude adjustment constraint based on the cycle interval information.

[0074] This step is crucial for achieving this selection. The preset periodic adjustment strategy pre-stores the mapping relationship between three periodic intervals and three amplitude adjustment constraints.

[0075] For example, the first cycle interval corresponds to the first amplitude adjustment constraint, which can be set to a power change rate not exceeding 5% / s; the second cycle interval corresponds to the second amplitude adjustment constraint, which can be set to a power change rate not exceeding 15% / s; the third cycle interval corresponds to the third amplitude adjustment constraint, which can be set to a power change rate not exceeding 30% / s or without restriction.

[0076] By comparing the period interval information obtained from S2 with the preset period adjustment strategy, the amplitude adjustment constraint to be used at the current time can be determined.

[0077] This amplitude adjustment constraint will be used to modify the propulsion power reference command in subsequent S6 operations. Since load characteristics differ at different disturbance frequencies, employing differentiated amplitude adjustment constraints can maximize energy savings and avoid excessive restrictions that could negatively impact propulsion response, while ensuring system stability.

[0078] For example, under low-frequency disturbances, if the stringent amplitude limits (such as 5% / s) used under high-frequency disturbances are still applied, it will lead to sluggish propulsion power response and affect ship maneuverability; while using more lenient limits (such as 30% / s or no limit) can balance response speed. This step solves the problem in the prior art that the uniform amplitude limit strategy cannot balance system stability and responsiveness under different disturbance frequencies by matching the period range and amplitude adjustment constraints.

[0079] This step achieves differentiated amplitude limits on propulsion power reference commands by matching the period range (high frequency, medium frequency, low frequency) of the voltage ripple period with different amplitude adjustment constraints in the preset period adjustment strategy. While suppressing load disturbances and improving power quality, it avoids sluggish propulsion power response or over-adjustment caused by uniform amplitude limits. This balances the energy-saving effect, operational stability, and control responsiveness of the ship's hybrid energy system, and solves the drawback of existing technologies that cannot dynamically adjust amplitude constraints according to disturbance frequency.

[0080] S4. Perform interval mapping processing on the voltage ripple phase data, mapping the voltage ripple phase data to a preset phase interval to obtain the phase interval information where the voltage ripple phase data is located.

[0081] A preset phase interval is obtained and extracted to obtain the phase interval boundary values ​​corresponding to the preset phase interval. The phase interval boundary values ​​include a first phase boundary value, a second phase boundary value, a third phase boundary value, and a fourth phase boundary value. The first phase boundary value, the second phase boundary value, the third phase boundary value, and the fourth phase boundary value divide a complete phase cycle into four phase intervals, and the fourth phase boundary value corresponds to the end point of the complete phase cycle.

[0082] In this implementation, the first phase boundary value is preset to 90 degrees, the second phase boundary value is preset to 180 degrees, the third phase boundary value is preset to 270 degrees, and the fourth phase boundary value is preset to 360 degrees.

[0083] Using one phase period as the modulus, the voltage ripple phase data is mapped to a preset phase interval to obtain mapped phase data. The mapped phase data is compared with the boundary values ​​of the phase interval to obtain a second comparison result, which is then determined as the phase interval information where the voltage ripple phase data is located.

[0084] Specifically, the mapped phase data is compared with the boundary value of the phase interval. When the mapped phase data is greater than or equal to 0 degrees and less than the first phase boundary value, the mapped phase data is in the first phase interval, and the first phase interval is determined as the second comparison result. When the mapped phase data is greater than or equal to the first phase boundary value and less than the second phase boundary value, the mapped phase data is in the second phase interval, and the second phase interval is determined as the second comparison result. When the mapped phase data is greater than or equal to the second phase boundary value and less than the third phase boundary value, the mapped phase data is in the third phase interval, and the third phase interval is determined as the second alignment result. When the mapped phase data is greater than or equal to the third phase boundary value and less than the fourth phase boundary value, the mapped phase data is in the fourth phase interval, and the fourth phase interval is determined as the second alignment result.

[0085] Through the above processing, the voltage ripple phase data is mapped to a preset phase interval to obtain the phase interval information where the voltage ripple phase data is located, which provides a basis for determining the phase adjustment direction of the propulsion power reference command in combination with the preset mechanical resonance frequency interval information.

[0086] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: A preset phase interval refers to a pre-defined numerical range used to divide the voltage ripple phase. It consists of multiple phase boundary values ​​within a complete phase cycle and is used to classify phase data into different phase regions.

[0087] Phase interval boundary values ​​refer to the boundary values ​​used to divide phase intervals, including the first phase boundary value, the second phase boundary value, the third phase boundary value, and the fourth phase boundary value.

[0088] The first phase boundary value refers to the first boundary value in the preset phase interval, which is 90 degrees in this embodiment, and is used to separate the first phase interval and the second phase interval.

[0089] The second phase boundary value refers to the second boundary value in the preset phase interval, which is 180 degrees in this embodiment, and is used to separate the second phase interval and the third phase interval.

[0090] The third phase boundary value refers to the third boundary value in the preset phase interval, which is 270 degrees in this embodiment, and is used to separate the third phase interval and the fourth phase interval.

[0091] The fourth phase boundary value refers to the fourth boundary value in the preset phase interval, which corresponds to the end of the complete phase cycle. In this embodiment, it is 360 degrees.

[0092] Using one phase period as the modulus means using 360 degrees or 2π radians as the period for modulo operation. This is used to constrain the voltage ripple phase data within the range of 0 to 360 degrees, eliminating out-of-bounds errors caused by phase accumulation.

[0093] Mapped phase data refers to the phase value obtained by performing a modulo operation on the original voltage ripple phase data with one phase period as the modulus. Its range is between 0 degrees and 360 degrees.

[0094] The second comparison result refers to the phase interval assignment result obtained by comparing the mapped phase data with the phase interval boundary value, including the first phase interval, the second phase interval, the third phase interval, or the fourth phase interval.

[0095] The first phase interval, in this embodiment, refers to the phase interval where the mapped phase data is greater than or equal to 0 degrees and less than 90 degrees.

[0096] The second phase interval, in this embodiment, refers to the phase interval where the mapped phase data is greater than or equal to 90 degrees and less than 180 degrees.

[0097] The third phase interval, in this embodiment, refers to the phase interval where the mapped phase data is greater than or equal to 180 degrees and less than 270 degrees.

[0098] The fourth phase interval, in this embodiment, refers to the phase interval where the mapped phase data is greater than or equal to 270 degrees and less than 360 degrees.

[0099] Phase interval information refers to the phase interval at which the voltage ripple phase data belongs, which is used to subsequently determine the phase adjustment direction of the propulsion power reference command by combining it with the preset mechanical resonance frequency interval information. In some possible implementations, different disturbance phases can have varying effects on the timing of the propulsion motor's power output, especially when the load disturbance frequency is close to the mechanical resonance frequency. The relative relationship between the power output phase and the disturbance phase directly determines whether mechanical resonance will be exacerbated. Therefore, it is necessary to divide the voltage ripple phase data into different phase intervals to select the phase adjustment direction of the power command based on the interval where the disturbance phase is located.

[0100] This step is designed to address this problem. Because voltage ripple phase data may accumulate over time and exceed the range of 0 to 360 degrees (for example, the phase value increases continuously after multiple cycles), directly using the original phase value for interval determination will lead to errors.

[0101] Therefore, using one phase period (360 degrees or 2π radians) as the modulus, the voltage ripple phase data is subjected to modulo operation and mapped to the standard range of 0 to 360 degrees to obtain the mapped phase data.

[0102] Based on the preset phase interval boundary values, the mapped phase data is assigned to one of the four phase intervals. For example, if the mapped phase data is 45 degrees, it belongs to the first phase interval; if the mapped phase data is 270 degrees, it belongs to the fourth phase interval.

[0103] This step involves performing modulo mapping and interval division on the voltage ripple phase data, classifying the original phase data into four preset phase intervals. This eliminates the numerical out-of-bounds problem caused by phase accumulation and discretizes the continuously changing phase into physically meaningful interval labels. This provides a unified reference for subsequent determination of the phase adjustment direction based on the mechanical resonance frequency. The system can distinguish between "dangerous phase windows" and "safe phase windows" based on the specific interval where the disturbance phase is located. Thus, when the load disturbance frequency is close to the resonance frequency, phase advance or delay adjustment is only applied to dangerous intervals (such as the first and third intervals), while the phase remains unchanged in safe intervals (such as the second and fourth intervals). This avoids power response lag or resonance aggravation caused by blind adjustment, achieving a balance between the accuracy of phase adjustment and system responsiveness, and effectively improving the mechanical safety and control quality of the propulsion shaft system.

[0104] S5, based on phase interval information, combined with preset phase adjustment strategy and preset mechanical resonance frequency interval information, determines the phase adjustment direction of the propulsion power reference command.

[0105] The disturbance frequency is determined based on the voltage ripple period. The disturbance frequency is then matched with the preset mechanical resonance frequency range information to obtain the frequency matching result, which includes both conforming and non-conforming results.

[0106] When the frequency matching result is satisfactory, the preset phase adjustment strategy is invoked based on the phase interval information to determine the phase adjustment direction of the propulsion power reference command.

[0107] In the preset phase adjustment strategy, different phase intervals correspond to different phase adjustment directions, including phase advance, phase delay, or phase remain unchanged.

[0108] For example, when the phase interval information is the first phase interval, the phase adjustment direction is phase delay; When the phase interval information is the second phase interval, the phase adjustment direction is to keep the phase unchanged; When the phase interval information is the third phase interval, the phase adjustment direction is phase advance; When the phase interval information is the fourth phase interval, the phase adjustment direction is to keep the phase unchanged.

[0109] When the frequency matching result is not met, the phase adjustment direction of the propulsion power reference command will be set to the default direction, which means that the phase remains unchanged.

[0110] Through the above processing, the phase adjustment direction of the propulsion power reference command is determined based on whether the disturbance frequency falls within the mechanical resonance frequency range and the range where the voltage ripple phase is located, providing a phase adjustment basis for subsequent modification of the output timing of the propulsion power reference command.

[0111] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: Disturbance frequency refers to the frequency value calculated based on the voltage ripple period, which is equal to the reciprocal of the voltage ripple period. It is used to characterize the frequency characteristics of propeller load disturbance.

[0112] Frequency matching result refers to the result obtained by comparing the disturbance frequency with the preset mechanical resonance frequency range information, including conformity (the disturbance frequency falls within the resonance frequency range) and non-conformity (the disturbance frequency does not fall within the resonance frequency range).

[0113] The preset phase adjustment strategy refers to the pre-defined correspondence that maps different phase intervals to different phase adjustment directions, and is used to determine the phase adjustment method of the propulsion power reference command based on the interval where the voltage ripple phase is located.

[0114] Phase adjustment direction refers to the direction in which the output timing of the propulsion power reference command is adjusted, including phase advance, phase delay, or phase remaining unchanged.

[0115] The default direction refers to the phase adjustment direction used when the frequency matching result is not satisfactory. It usually keeps the phase unchanged to avoid unnecessary phase adjustment.

[0116] In some possible implementations, when the propeller load disturbance frequency is close to the shaft system's mechanical resonant frequency, propulsion power is typically controlled using fixed phase compensation or by completely disregarding phase effects. This approach ignores the strong correlation between resonant excitation and disturbance phase: within a disturbance cycle, not all phases excite resonance to the same degree; only within a specific "dangerous phase window" will the power output significantly exacerbate vibration. However, the location of the dangerous phase window varies for different shaft systems, depending on the shaft system's mode shape, damping characteristics, and load disturbance type. Using fixed phase adjustment rules (e.g., uniform delay or advance) may be effective under certain operating conditions, but may worsen resonance under others.

[0117] This step is based on the above understanding and achieves targeted phase adjustment through a preset phase adjustment strategy. This strategy does not rigidly divide the danger zone according to a fixed angle (such as 0 degrees-90 degrees), but is pre-calibrated based on the dynamic test data of the actual shaft system.

[0118] The specific calibration method includes: applying an excitation with a known phase to the shaft system, measuring the amplitude of the resonance response, and thus plotting a "phase-resonance response" curve to identify the phase window (usually one or two consecutive intervals) where the excitation resonance is most significant. Then, the phase interval corresponding to this window is marked as the "interval that needs adjustment", and the rest are "safe intervals".

[0119] In this embodiment, for ease of explanation, the calibration results are assumed to be as follows: the first and third phase intervals are danger windows and require adjustment; the second and fourth phase intervals are safe windows and do not require adjustment. This division may stem from the symmetry characteristics of the shaft system and does not represent this for all shaft systems.

[0120] For the intervals requiring adjustment, the adjustment direction is further selected based on the resonance mechanism: if the danger window is located in the rising segment of the disturbance, phase delay is used to avoid power output; if it is located in the falling segment, phase advance is used. In this embodiment, the first interval is set as phase delay and the third interval is set as phase advance.

[0121] This step matches and judges the disturbance frequency with the mechanical resonance frequency range. Based on whether the disturbance frequency threatens mechanical safety and whether the disturbance phase is in a dangerous window, it achieves differentiated phase adjustment. While effectively suppressing the risk of mechanical resonance caused by load disturbance, it avoids unnecessary phase adjustment that causes power response lag. Thus, it takes into account both shaft safety and the dynamic response performance of the propulsion system. It solves the problem of resonance aggravation or response sluggishness caused by using fixed phase compensation or completely ignoring phase coupling in the prior art.

[0122] It should be noted that the above mapping relationship between the phase interval and the adjustment direction is only an example. In actual applications, it can be recalibrated according to the specific characteristics of the shaft system. This embodiment does not constitute a limitation.

[0123] S6 modifies the propulsion power reference command based on amplitude adjustment constraints and phase adjustment direction, generates propulsion motor power command, and outputs propulsion motor power command to control the propulsion motor to drive the propeller.

[0124] The propulsion power reference command is extracted to obtain the target power value and output timing. Based on amplitude adjustment constraints, the target power value is limited to obtain a modified target power value. Based on phase adjustment direction, the output timing is adjusted to obtain a modified output timing. The modified target power value and modified output timing are encapsulated to generate the propulsion motor power command.

[0125] The propulsion motor power command is output to the propulsion motor controller, which controls the propulsion motor to drive the propeller according to the modified target power value and output timing.

[0126] Through the above processing, the power amplitude is limited by the amplitude adjustment constraint determined by the period interval where the voltage ripple period is located, and the output timing is adjusted by the phase adjustment direction determined by the phase interval where the voltage ripple phase is located and the mechanical resonance frequency matching result. This generates a propulsion motor power command that takes into account both power quality and mechanical safety, thereby realizing energy-saving optimization control of the ship's hybrid energy system.

[0127] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first: The target power value refers to the expected output power value of the propulsion motor extracted from the propulsion power reference command, which is used for subsequent amplitude limiting processing.

[0128] Output timing refers to the time sequence information of power output extracted from propulsion power reference commands, including the start time, duration, and variation pattern of power output.

[0129] The modified target power value refers to the power value obtained after limiting the target power value according to the amplitude adjustment constraint, which is used to generate the propulsion motor power command.

[0130] The modified output timing refers to the time sequence obtained after adjusting the output timing according to the phase adjustment direction, which is used to generate the propulsion motor power command.

[0131] The propulsion motor power command is the final command generated after modifying the amplitude and phase of the propulsion power reference command. It is used to control the propulsion motor to drive the propeller.

[0132] A propulsion motor controller is a control unit that receives power commands from the propulsion motor and drives the propulsion motor to perform the corresponding power output.

[0133] In some possible implementations, this step modifies the propulsion power reference command through two dimensions: amplitude adjustment constraints and phase adjustment direction.

[0134] The amplitude adjustment constraint is determined based on the period interval (i.e., the disturbance frequency interval) where the voltage ripple period is located, and is used to limit the range and rate of change of the power amplitude.

[0135] For example, when the voltage ripple period is in the first period range (high-frequency disturbance), the amplitude adjustment constraint can be set to ensure that the power change rate does not exceed a certain small threshold to suppress high-frequency fluctuations; when it is in the third period range (low-frequency disturbance), the amplitude adjustment constraint can be set to be more lenient or not restricted to ensure propulsion response speed.

[0136] The phase adjustment direction is determined based on the phase range of the voltage ripple phase and whether the disturbance frequency falls within the mechanical resonant frequency range, and is used to adjust the timing of the power output. For example, when the disturbance frequency is close to the resonant frequency and the phase is in a certain dangerous range, the phase adjustment direction is set to phase delay, so that the power output is staggered from the phase point where the resonance intensifies.

[0137] In practice, the target power value and output timing are extracted from the propulsion power reference command.

[0138] Amplitude limiting can be achieved using a limiter or a rate of change limiter, for example, by setting an upper and lower limit for the power value, or by setting the maximum allowable value for the power difference between adjacent times.

[0139] Timing adjustment can be achieved by delay or phase shift. For example, the overall output timing can be advanced or delayed by a preset phase angle depending on the phase adjustment direction.

[0140] After the modified target power value and the modified output timing are repackaged, a propulsion motor power command is generated and sent to the propulsion motor controller for execution.

[0141] This step enables power command correction based on load disturbance characteristics and mechanical resonance characteristics, which suppresses power quality problems while ensuring shaft mechanical safety. It solves the problems of existing filtering methods being unable to distinguish disturbance frequencies and not considering phase and resonance coupling, and achieves the synergistic control effect of energy-saving optimization and operational safety of ship hybrid energy systems.

[0142] This application extracts the voltage ripple period and uses the physical mapping relationship between shaft frequency and blade frequency to determine the boundary value of the period interval, dividing the voltage ripple period into three intervals: high frequency, medium frequency, and low frequency. Then, it matches different amplitude adjustment constraints in the preset period adjustment strategy, thereby avoiding insufficient high-frequency suppression or sluggish low-frequency response caused by uniform amplitude limitation. This allows the dynamic responsiveness and energy-saving effect of the propulsion system to be taken into account while suppressing load disturbances and improving power quality. It solves the drawback of existing technologies that cannot dynamically adjust amplitude constraints according to the disturbance frequency.

[0143] This application maps voltage ripple phase data to a preset phase range and pre-calibrates dangerous and safe phase windows based on shaft dynamics tests. When the disturbance frequency falls into the resonance range, only the dangerous window is delayed or advanced to make the power output staggered from the phase point of resonance aggravation, while the safe window remains unchanged in phase. Moreover, the phase adjustment direction is precisely matched with the degree of danger of the disturbance phase, avoiding blind adjustment that would cause power response lag or resonance deterioration. Thus, while effectively suppressing the risk of mechanical resonance, it ensures the control responsiveness of the propulsion system and solves the safety hazards caused by the failure to consider phase-resonance coupling in the prior art.

[0144] Example 2: This application provides an energy-saving optimization control system for ship hybrid energy. The system functions according to the specific implementation steps in Example 1, including a data acquisition module, a processing module, an instruction generation module, and an output module. Please refer to [link to example 1]. Figure 2 .

[0145] The acquisition module is used to acquire voltage ripple period, voltage ripple phase data and propulsion power reference command caused by the periodic change of propeller load, as well as to acquire shaft frequency signal, blade frequency signal and preset mechanical resonance frequency range information of the propeller. The processing module includes a period processing unit and a phase processing unit. The period processing unit is used to determine the boundary value of the period interval based on the shaft frequency signal and the blade frequency signal, and to determine the period interval of the voltage ripple period according to the boundary value of the period interval, thereby obtaining the period interval information where the voltage ripple period is located. Based on the period interval information and the preset period adjustment strategy, the amplitude adjustment constraint of the propulsion power reference command is determined. The phase processing unit is used to perform interval mapping processing on the voltage ripple phase data, map the voltage ripple phase data to a preset phase interval, obtain the phase interval information where the voltage ripple phase data is located, and determine the phase adjustment direction of the propulsion power reference command based on the phase interval information combined with the preset phase adjustment strategy and the preset mechanical resonance frequency interval information. The instruction generation module is used to modify the propulsion power reference instruction based on the amplitude adjustment constraint and the phase adjustment direction to generate the propulsion motor power instruction; The output module is used to output power commands for the propulsion motor, controlling the propulsion motor to drive the propeller.

[0146] The functions of the above modules correspond to the method description in Example 1, and will not be described in detail here.

[0147] This application provides an energy-saving optimization control system for ship hybrid energy, which achieves synergistic optimization of load disturbance suppression and mechanical resonance avoidance, effectively improving the energy efficiency, operational stability and shafting safety of the ship hybrid energy system.

[0148] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for energy-saving optimization control of ship hybrid energy, characterized in that, The method includes: Acquire voltage ripple period, voltage ripple phase data, and propulsion power reference command caused by periodic changes in propeller load; Acquire the shaft frequency signal, blade frequency signal, and preset mechanical resonance frequency range information of the propeller; Based on the shaft frequency signal and the blade frequency signal, determine the boundary values ​​of the period interval; Based on the boundary value of the period interval, the voltage ripple period is determined to obtain the period interval information where the voltage ripple period is located; Based on the period interval information and combined with the preset period adjustment strategy, the amplitude adjustment constraint of the propulsion power reference command is determined. The voltage ripple phase data is subjected to interval mapping processing to map the voltage ripple phase data to a preset phase interval, thereby obtaining the phase interval information where the voltage ripple phase data is located. Based on the phase interval information, combined with the preset phase adjustment strategy and the preset mechanical resonance frequency interval information, the phase adjustment direction of the propulsion power reference command is determined; Based on the amplitude adjustment constraint and the phase adjustment direction, the propulsion power reference command is modified to generate a propulsion motor power command; Output the propulsion motor power command to control the propulsion motor to drive the propeller; The step of determining the boundary values ​​of the period interval based on the shaft frequency signal and the blade frequency signal includes: The shaft frequency signal is analyzed to obtain the reference rotation frequency; The blade frequency signal is analyzed to obtain the blade passing frequency; Using the reference rotation frequency as the first reference frequency, and based on the correspondence between the period and the frequency, a first period value corresponding to the first reference frequency is determined. The frequency through which the blade passes is used as the second reference frequency. Based on the correspondence between the period and the frequency, the second period value corresponding to the second reference frequency is determined. By comparing the first period value with the second period value and combining the correspondence between period and frequency, it is found that the first period value is greater than the second period value. The first period value and the second period value are determined as the boundary values ​​of the period interval; Wherein, the first period value is the boundary value of the maximum period interval, and the second period value is the boundary value of the minimum period interval.

2. The method according to claim 1, characterized in that, The step of determining the voltage ripple period based on the period interval boundary value to obtain the period interval information where the voltage ripple period is located includes: The voltage ripple period is compared with the boundary value of the period interval to obtain a first comparison result, and the first comparison result is determined as the period interval information where the voltage ripple period is located.

3. The method according to claim 2, characterized in that, The step of comparing the voltage ripple period with the boundary value of the period interval to obtain a first comparison result includes: When the voltage ripple period is less than the second period value, the voltage ripple period is in the first period interval, and the first period interval is determined as the first comparison result. When the voltage ripple period is greater than or equal to the second period value and less than or equal to the first period value, the voltage ripple period is in the second period interval, and the second period interval is determined as the first comparison result. When the voltage ripple period is greater than the first period value, the voltage ripple period is in the third period interval, and the third period interval is determined as the first comparison result.

4. The method according to claim 3, characterized in that, The step of determining the amplitude adjustment constraint of the propulsion power reference command based on the period interval information and in conjunction with a preset period adjustment strategy includes: The period interval information is compared with the preset period adjustment strategy to determine the target strategy corresponding to the period interval information within the preset period adjustment strategy, and the target strategy is determined as the amplitude adjustment constraint of the propulsion power reference command. In the preset period adjustment strategy, the first period interval, the second period interval, and the third period interval each correspond to different amplitude adjustment constraints.

5. The method according to claim 1, characterized in that, The step of performing interval mapping processing on the voltage ripple phase data, mapping the voltage ripple phase data to a preset phase interval, and obtaining the phase interval information where the voltage ripple phase data is located, includes: Obtain a preset phase interval, and extract the preset phase interval to obtain the phase interval boundary value corresponding to the preset phase interval; Using one phase period as the modulus, the voltage ripple phase data is mapped to a preset phase interval to obtain mapped phase data; The mapped phase data is compared with the phase interval boundary value to obtain a second comparison result, and the second comparison result is determined as the phase interval information where the voltage ripple phase data is located; The phase interval boundary values ​​include a first phase boundary value, a second phase boundary value, a third phase boundary value, and a fourth phase boundary value. The first phase boundary value, the second phase boundary value, the third phase boundary value, and the fourth phase boundary value divide a complete phase cycle into four phase intervals, and the fourth phase boundary value corresponds to the end of the complete phase cycle.

6. The method according to claim 5, characterized in that, The step of comparing the mapped phase data with the phase interval boundary value to obtain a second comparison result includes: The mapped phase data is compared with the phase interval boundary value. When the mapped phase data is less than the first phase boundary value, the mapped phase data is in the first phase interval, and the first phase interval is determined as the second comparison result. When the mapped phase data is greater than or equal to the first phase boundary value and less than the second phase boundary value, the mapped phase data is in the second phase interval, and the second phase interval is determined as the second comparison result. When the mapped phase data is greater than or equal to the second phase boundary value and less than the third phase boundary value, the mapped phase data is in the third phase interval, and the third phase interval is determined as the second comparison result. When the mapped phase data is greater than or equal to the third phase boundary value and less than or equal to the fourth phase boundary value, the mapped phase data is in the fourth phase interval, and the fourth phase interval is determined as the second comparison result.

7. The method according to claim 6, characterized in that, The step of determining the phase adjustment direction of the propulsion power reference command based on the phase interval information, combined with a preset phase adjustment strategy and the preset mechanical resonance frequency interval information, includes: The disturbance frequency is determined based on the voltage ripple period; The perturbation frequency is matched with the preset mechanical resonance frequency range information to obtain a frequency matching result, which includes both conforming and non-conforming results. When the frequency matching result is satisfactory, based on the phase interval information, a preset phase adjustment strategy is invoked to determine the phase adjustment direction of the propulsion power reference command; If the frequency matching result is not met, the phase adjustment direction of the propulsion power reference command is determined as the default direction.

8. The method according to claim 7, characterized in that, The modification of the propulsion power reference command based on the amplitude adjustment constraint and the phase adjustment direction to generate a propulsion motor power command includes: The propulsion power reference command is extracted to obtain the target power value and output timing. Based on the amplitude adjustment constraint, the target power value is amplitude limited to obtain the modified target power value; Based on the phase adjustment direction, the output timing is adjusted to obtain the modified output timing; The modified target power value and the modified output timing are encapsulated to generate a propulsion motor power command.

9. An energy-saving optimization control system for ship hybrid energy, characterized in that, The system includes: Acquisition module, processing module, instruction generation module, and output module; The acquisition module is used to acquire voltage ripple period, voltage ripple phase data and propulsion power reference command caused by the periodic change of propeller load, as well as to acquire shaft frequency signal, blade frequency signal and preset mechanical resonance frequency range information of the propeller. The processing module includes a period processing unit and a phase processing unit. The period processing unit is used to determine the period interval boundary value based on the shaft frequency signal and the blade frequency signal, and to perform interval determination on the voltage ripple period according to the period interval boundary value to obtain the period interval information where the voltage ripple period is located. Based on the period interval information and a preset period adjustment strategy, the amplitude adjustment constraint of the propulsion power reference command is determined. The phase processing unit is used to perform interval mapping processing on the voltage ripple phase data, map the voltage ripple phase data to a preset phase interval, obtain the phase interval information where the voltage ripple phase data is located, and determine the phase adjustment direction of the propulsion power reference command based on the phase interval information combined with a preset phase adjustment strategy and the preset mechanical resonance frequency interval information. The instruction generation module is used to modify the propulsion power reference instruction based on the amplitude adjustment constraint and the phase adjustment direction to generate a propulsion motor power instruction. The output module is used to output the power command of the propulsion motor and control the propulsion motor to drive the propeller to run; The step of determining the boundary values ​​of the period interval based on the shaft frequency signal and the blade frequency signal includes: The shaft frequency signal is analyzed to obtain the reference rotation frequency; The blade frequency signal is analyzed to obtain the blade passing frequency; Using the reference rotation frequency as the first reference frequency, and based on the correspondence between the period and the frequency, a first period value corresponding to the first reference frequency is determined. The frequency through which the blade passes is used as the second reference frequency. Based on the correspondence between the period and the frequency, the second period value corresponding to the second reference frequency is determined. By comparing the first period value with the second period value and combining the correspondence between period and frequency, it is found that the first period value is greater than the second period value. The first period value and the second period value are determined as the boundary values ​​of the period interval; Wherein, the first period value is the boundary value of the maximum period interval, and the second period value is the boundary value of the minimum period interval.

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