Ship integrated power system based on load current feedforward

Abstract

This invention relates to a shipboard integrated power system based on load current feedforward, which solves the problem of DC bus voltage fluctuations caused by rapid load changes in shipboard power systems. It belongs to the field of shipboard power system and DC microgrid technology. The invention includes: a generator-rectifier system connected to the DC bus as the main power supply; an energy storage system connected to the DC bus as a compensation device for the main power supply; a load power supply system connected to the DC bus through a corresponding load converter; and a microgrid controller connected to the generator-rectifier system, energy storage system, and load power supply system. The microgrid controller includes: a data acquisition module for acquiring the total load current of the load power supply system; a frequency division module for decomposing the total load current into low-frequency and high-frequency components; and a feedback coordination control module for sending the low-frequency component as a feedforward quantity to the generator-rectifier system and the high-frequency component as a feedforward quantity to the energy storage system.

Description

Technical Field

[0001] This invention relates to a ship integrated power system based on load current feedforward, belonging to the field of ship power system and DC microgrid technology. Background Technology

[0002] With the rapid development of power electronics technology and control theory, ship systems are gradually integrating power systems with propulsion systems, becoming integrated shipboard power systems. Centralized power supply and unified dispatching of propulsion devices and auxiliary equipment through integrated shipboard power systems can improve the overall energy efficiency and maneuverability of ships. However, as an isolated DC microgrid, the shipboard microgrid mostly uses diesel engines and gas turbines for power supply, resulting in weaker voltage support compared to land-based DC microgrids supported by a large power grid. Simultaneously, with the development of various electrical equipment, the types of electrical equipment on ships have increased. These devices generate significant voltage fluctuations during startup, speed changes, or load switching during navigation. As the power demand of shipboard electrical equipment gradually increases, the switching of various high-power electrical loads, such as propulsion loads, affects the voltage stability of the shipboard microgrid bus, thereby reducing system power quality and affecting the normal operation of various electrical equipment.

[0003] Currently, to reduce voltage fluctuations caused by high-power load switching and improve the stability of shipboard power systems, existing research mainly adopts measures such as increasing bus capacitance, adding energy storage modules, and improving control strategies to reduce DC bus voltage fluctuations. However, increasing bus capacitance increases equipment size and only provides minor suppression; adding energy storage modules such as flywheels and lithium batteries incurs high configuration and maintenance costs; while improving control strategies places higher demands on the controller, it effectively reduces costs and eliminates the need for large, heavy equipment. In shipboard integrated power systems, voltage fluctuations mainly stem from the inability of traditional converter control methods to quickly track sudden increases and decreases in load power. These improved control strategies aim to change the dynamic response speed of the control loop and improve system responsiveness. By optimizing converter voltage and current control strategies for coordinated control of the integrated power system, they can effectively mitigate large bus voltage fluctuations caused by rapid changes in high-power loads. Summary of the Invention

[0004] To address the problem of DC bus voltage fluctuations caused by rapid load changes in ship power systems, this invention provides a ship integrated power system based on load current feedforward.

[0005] The present invention provides a shipboard integrated power system based on load current feedforward, comprising:

[0006] The generator-rectifier system is connected to the DC bus as the main power source;

[0007] The energy storage system is connected to the DC bus and serves as a compensation device for the main power supply.

[0008] The load power supply system is connected to the DC bus through a corresponding load converter;

[0009] The microgrid controller is connected to the generator-rectifier system, the energy storage system, and the load power supply system, respectively.

[0010] The microgrid controller includes:

[0011] The acquisition module is used to obtain the total load current of the load power supply system;

[0012] The frequency divider module is used to decompose the total load current into low-frequency and high-frequency components.

[0013] The feedback coordination control module is used to send low-frequency components as feedforward to the generator-rectifier system and high-frequency components as feedforward to the energy storage system.

[0014] As a preferred approach, the feedback coordination control module sends low-frequency components as feedforward quantities to the generator-rectifier system.

[0015] The d-axis and q-axis reference currents are:

[0016]

[0017] in, Based on the fundamental current component, the current component introduced by the low-frequency component is...

[0018]

[0019] This is the measured value of the DC bus voltage. Let be the d-axis component of the generator's three-phase terminal voltage in a rotating coordinate system. Low-frequency components;

[0020] A dual closed-loop control architecture of voltage and current is adopted for the rectifier in the generator-rectifier system. Without changing the outer voltage loop, the d-axis and q-axis reference currents are input into the inner current loop to control the generator-rectifier system.

[0021] As a preferred option, the basic current component for:

[0022]

[0023] in, This is the voltage loop proportionality coefficient. The voltage loop integral coefficient, This is the reference value for the DC bus voltage. Indicates time.

[0024] Preferably, in the feedback coordination control module, the method of sending high-frequency components as feedforward quantities to the energy storage system includes:

[0025] Through high frequency components The converted current reference value was calculated. for:

[0026]

[0027] in, This refers to the input voltage of the DC-DC converter in the energy storage system. This refers to the output voltage of the DC-DC converter in the energy storage system.

[0028] For current reference value Dynamic amplitude limiting:

[0029]

[0030] in, and These are the maximum allowable output current and the maximum allowable input current of the battery, respectively.

[0031] The current reference value after limiting The input is fed into the current control loop to control the energy storage system.

[0032] Preferably, the current reference value The modulation signal is input into the current control loop. :

[0033]

[0034] in, This is the proportional coefficient of the current control loop. The integral coefficient of the current control loop. Indicates the current on the energy storage device side. Indicates time;

[0035] According to the modulation signal Control the energy storage system.

[0036] As a preferred method, the acquisition module uses the following method to obtain the total load current of the load power supply system:

[0037] A low-pass filter is used to remove high-frequency interference near the switching frequency, and the current after interference removal is used for load current feedback. :

[0038]

[0039] Among them, the angular frequency of the low-pass filter , The cutoff frequency, and , The frequency of the pulse load, This represents the switching frequency.

[0040] As a preferred option, the low-frequency component is:

[0041]

[0042] The high-frequency components are:

[0043]

[0044] This is the total load current. , As the frequency division point, It is a complex frequency.

[0045] Preferably, the generator-rectifier system includes a generator, an L-type filter, a three-phase rectifier, and a filter capacitor; the three-phase AC output terminal of the generator is connected in series with the input terminal of the L-type filter, and the output terminal of the L-type filter is electrically connected to the AC input side of the three-phase rectifier; the DC output side of the three-phase rectifier is connected in parallel with the filter capacitor, and the two ends of the filter capacitor are connected to the DC bus.

[0046] The transmission of electrical energy between the generator-rectifier system and the DC bus is controlled based on the low-frequency component.

[0047] Preferably, the energy storage system includes a battery pack, a bidirectional Buck / Boost converter, an input-side filter capacitor, and an output-side filter capacitor. The positive and negative terminals of the battery pack are connected in parallel with the low-voltage side of the bidirectional Buck / Boost converter, and an input-side filter capacitor is connected in parallel between the battery pack and the bidirectional Buck / Boost converter.

[0048] The high-voltage side of the bidirectional Buck / Boost converter is connected in parallel with an output-side filter capacitor, and the two ends of the output-side filter capacitor are connected to the DC bus.

[0049] The bidirectional Buck / Boost converter uses a current control loop to control the bidirectional transmission of electrical energy between the battery pack and the DC bus based on high-frequency components.

[0050] Preferably, the load power supply system includes at least one of a propulsion motor system, a pulse load power supply system, an AC load power supply system, and a DC load power supply system. The beneficial effects of this invention are that it supports the DC bus voltage using a generator-rectifier system as the main power source. For different types of loads on the ship, the microgrid controller is configured with dedicated and adapted control strategies. By simplifying the architecture and clearly defining the division of labor, it achieves differentiated and precise power supply for AC and DC loads to adapt to the operating characteristics of the ship's isolated DC microgrid. This invention uses a load current frequency division method, employing a low-pass filter to attenuate signals near the switching frequency, reducing the impact of high-frequency disturbances on the control loop. Simultaneously, it adapts to the dynamic response characteristics of the generator-rectifier system and the energy storage system to achieve reasonable segmentation of the low-frequency and high-frequency components of the load current, avoiding problems such as untimely generator response and excessive burden on the energy storage system. This invention improves the response speed of the generator-rectifier system to sudden load current changes by using a coordinated control method based on load current feedback. It also compensates for high-frequency load current impacts by relying on the rapid response of the energy storage system. This achieves synergistic cooperation and complementary advantages between the two micro-sources, eliminating the need for additional large-volume bus capacitors and significantly improving the power quality of the ship's integrated power system. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the integrated power system structure of a ship.

[0052] Figure 2 This is a schematic diagram of the circuit structure of each parallel converter in a ship's microgrid.

[0053] Figure 3 This is a diagram illustrating the load current filtering and frequency division process.

[0054] Figure 4 This is a control block diagram of a generator-rectifier system.

[0055] Figure 5 This is a control block diagram of an energy storage system.

[0056] Figure 6 This is a flowchart of the energy storage system operation. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0059] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0060] The ship's integrated electric power system is a microgrid located on each of the ship's port and starboard sides. It controls the electrical energy within the system through converters. A schematic diagram of the ship's integrated electric power system is shown below. Figure 1 As shown, this embodiment of the ship's integrated power system based on load current feedforward includes a generator-rectifier system, an energy storage system, a load power supply system, and a microgrid controller. The control method of this embodiment operates in the microgrid controller. As the core coordination and real-time control unit of the ship's DC microgrid, the microgrid controller is responsible for the unified coordination and centralized control of multiple source, storage, and load devices within the system.

[0061] The generator-rectifier system connects to the DC bus as the main power source, providing the bus voltage required for system operation. The energy storage system acts as a compensation device, supplementing the current required by the system. The microgrid controller collects real-time operating status information of each source, storage, and load device, and combines it with preset control strategies to uniformly allocate and dynamically adjust control commands for each device. On the one hand, it collects key status information such as bus voltage and load current and completes data processing. On the other hand, through load current feedforward, it distributes the power components of load fluctuations to the energy storage and generator sets respectively, realizing rapid compensation for power fluctuations and steady-state power support. It constructs a closed-loop control system for source and storage coordinated regulation, ensuring the stable operation and optimized energy distribution of the entire microgrid under load fluctuation conditions.

[0062] As a DC microgrid, the ship's integrated power system includes various power sources and loads connected in parallel to the same DC bus through converters. The basic structure of this integrated power system includes: generator-rectifier system, energy storage system, and load power supply system.

[0063] In the integrated shipboard power system provided in this embodiment, in terms of power transmission, the power from the generator-rectifier system is transmitted to the DC bus to supply the load power supply system. Each load power supply system is powered through a separate converter. The energy storage system, acting as a power compensation device, is connected to the DC bus. The power of the energy storage system flows bidirectionally and can be flexibly adjusted according to the system's conditions. The topology of each subsystem is as follows:

[0064] The main structure of the generator-rectifier system consists of a generator, a three-phase rectifier, and a filter capacitor. The generator-rectifier system includes a generator, an L-type filter, a three-phase rectifier, and a filter capacitor. The three-phase AC output of the generator is connected in series with the input of the L-type filter. After filtering by the L-type filter, the output of the L-type filter is electrically connected to the AC input side of the three-phase rectifier. The rectifier converts AC to DC and adjusts the voltage to the level required by the DC bus. The DC output of the three-phase rectifier is connected in parallel with the filter capacitor, and both ends of the filter capacitor are connected to the DC bus. The transmission of electrical energy between the generator-rectifier system and the DC bus is controlled based on low-frequency components. The control method used is a dual closed-loop control architecture of voltage and current, providing stable bus voltage support for the system through an outer voltage loop and an inner current loop.

[0065] Its detailed circuit structure diagram is as follows: Figure 2 As shown in (a), the generator generates electricity, and its port voltage is... The generator port is connected in series with an L-type filter for filtering before being connected to the rectifier. To accommodate the current flowing through the AC-side filter inductor L, the main structure of the rectifier is a three-phase bridge converter. A capacitor C is connected in parallel at the output port of the rectifier, and finally, it is connected to the DC bus. The rectifier operates in voltage source mode, outputting a stable bus voltage. This generator-rectifier system acts as a power source, providing electrical energy and voltage support to the loads of the entire DC microgrid. The rectifier port voltage... This is the DC bus voltage.

[0066] The energy storage system includes a battery pack, a bidirectional Buck / Boost converter, an input-side filter capacitor, and an output-side filter capacitor. The positive and negative terminals of the battery pack are connected in parallel with the low-voltage side of the bidirectional Buck / Boost converter, and an input-side filter capacitor is connected in parallel between the battery pack and the bidirectional Buck / Boost converter. An output-side filter capacitor is connected in parallel with the high-voltage side of the bidirectional Buck / Boost converter, and its two ends are connected to the DC bus. The bidirectional Buck / Boost converter uses a current control loop to control the bidirectional transmission of electrical energy between the battery pack and the DC bus based on high-frequency components. The main structure of the energy storage system consists of a battery pack, a bidirectional Buck / Boost converter, and capacitors. Its circuit diagram is shown below. Figure 2 As shown in (b), the input capacitor is connected in parallel to the battery pack port. Then it is connected to a bidirectional Buck / Boost converter. A capacitor connected in parallel to the output port of a bidirectional Buck / Boost converter, and a switching transistor. and With complementary conduction, this converter is controlled by a current control loop. The input current of the converter, This is the output current of the converter.

[0067] The load power supply system includes at least one of the following: propulsion motor system, pulse load power supply system, AC load power supply system, and DC load power supply system. The propulsion motor system, as the core load of the ship, provides power for its navigation. It supplies power to the motor via an inverter connected to the bus, and its power is affected by speed commands or load torque. The pulse load power supply system outputs stable low-voltage DC power through an isolated dual active bridge DC-DC converter connected to the DC bus to power this special type of DC load. Other AC load power supply systems output stable low-voltage AC power through inverters to centrally power other AC loads besides the propulsion motor. Other DC load power supply systems output stable low-voltage DC power through DC-DC converters to centrally power other DC loads besides the pulse load. The topology is as follows: The main structure of the propulsion motor system consists of a three-phase inverter, a permanent magnet synchronous motor, and the propulsion load, such as... Figure 2 As shown in (c), the input of the converter is connected in parallel to the DC bus. Electrical energy is converted to AC by the inverter and supplied to the permanent magnet synchronous motor. Simultaneously, the permanent magnet synchronous motor has a propulsion load. When the speed or torque of the propulsion motor system changes abruptly, it will cause significant fluctuations in the bus voltage; as shown in (c). Figure 2 As shown in (d), the main structure of the pulse load power supply system consists of an LC filter at the input, a dual active bridge DC / DC converter, parallel capacitors on the input and output sides, and a pulse load. The output voltage of the converter is stabilized near the reference value through a voltage control loop, while the load current will exhibit a high-frequency pulse form, causing periodic fluctuations in the bus voltage. The main structure of other AC load power supply systems consists of a three-phase inverter and an AC load, such as... Figure 2 As shown in (e), the inverter operates in voltage source mode, providing stable AC power to the load. Switching between parallel AC loads on the output side causes bus voltage fluctuations. Other DC load power supply systems mainly consist of a Buck converter and DC loads, such as... Figure 2 As shown in (f), the Buck converter operates in voltage source mode, providing a stable voltage to the DC load. The switching of each parallel DC load on the output side will cause bus voltage fluctuations.

[0068] Various loads are powered by connecting to the bus via corresponding converters. The permanent magnet synchronous motor of the propulsion motor system is powered by an inverter connected to the bus, using a dual closed-loop control method of speed and current. Its power is mainly affected by the speed command of the control loop and the load torque of the propulsion motor. The pulse load of the pulse load power supply system is powered by an isolated DC-DC converter connected to the bus, using a voltage control loop. Its power is affected by its own pulse load current. Other AC load power supply systems and other DC load power supply systems are powered by inverters and DC-DC converters respectively, all using a dual closed-loop control architecture. The power is affected by the load switching.

[0069] As can be seen from the above, all the main converters of this ship's integrated power system are connected to the DC bus of the microgrid in parallel. The stability of the DC bus voltage determines the power quality of this ship's integrated power system. Sudden changes in high-power loads will generate large current fluctuations. At the same time, the load connected to the bus through multiple switching converters will also bring high-frequency disturbances to the system. It is necessary to improve the controller's response speed to sudden changes in load current and compensate for the load current, thereby reducing the bus voltage fluctuations caused by sudden changes in load.

[0070] To address load current and bus voltage fluctuations caused by sudden load changes, the microgrid controller in this embodiment employs coordinated control of the generator-rectifier system and the energy storage system. Different frequency bands of current feedforward are introduced to improve system response speed and DC bus voltage stability. Generator sets have slow response and low regulation bandwidth, making them suitable for providing low-frequency current, while energy storage systems have fast response and high regulation bandwidth, making them suitable for providing high-frequency current. Therefore, the load current needs to be frequency-divided when designing the current feedforward. The load current filtering and frequency division process is as follows: Figure 3 As shown, the following is the specific process of current processing:

[0071] The microgrid controller in this embodiment includes:

[0072] The acquisition module is used to obtain the total load current of the load power supply system;

[0073] The frequency divider module is used to decompose the total load current into low-frequency and high-frequency components.

[0074] The feedback coordination control module is used to send low-frequency components as feedforward to the generator-rectifier system and high-frequency components as feedforward to the energy storage system.

[0075] The acquisition module samples and summarizes the system's load current to obtain the total system load current. ;

[0076] Due to the total load current of the system High-frequency interference, represented by the switching frequency, exists. Therefore, the total load current needs to be preprocessed. A first-order low-pass filter is used to filter out high-frequency interference, while retaining the current components adapted to the generator and energy storage system, thus obtaining the load current after filtering out interference near the switching frequency. As shown in the following formula:

[0077]

[0078] in, This is the filtered load current. The measured total load current before filtering. , This is the transfer function of the switching frequency filter.

[0079] As the cutoff frequency of the switching frequency filter, The value needs to be sufficiently attenuated from the switching frequency. And it cannot be lower than the frequency of the pulse load. That is, it cannot affect the current feedforward component used to reduce bus voltage fluctuations, therefore its selection principle is as follows:

[0080]

[0081] The frequency divider module filters the total load current obtained after switching frequency filtering. Frequency segmentation is performed, decomposing the frequency into high-frequency and low-frequency components. A reasonable frequency division point is then set based on the operating characteristics of the DC microgrid and the dynamic response characteristics of the generator-rectifier system and energy storage system. Its value range is This avoids the generator-rectifier system failing to respond promptly due to excessively high frequency division points and avoids overburdening the energy storage system. The frequency segmentation is shown in the following formula:

[0082]

[0083] in, It is a low-frequency current component. For high-frequency current components, frequency segmentation is achieved through filters.

[0084] The frequency division principle is shown in the following formula:

[0085]

[0086] in, and These are the transfer functions of the low-pass filter and the high-pass filter, respectively. .

[0087] Based on the above frequency segmentation results, the feedback coordination control module connects the two separated current components to the control loops of the generator-rectifier system and the energy storage system DC converter, respectively, as reference current components for the current control loop. In the form of current feedforward, it realizes bus voltage fluctuation suppression and fast response control.

[0088] For the control of the generator-rectifier system, in this embodiment, the feedback coordination control module adopts a voltage and current dual closed-loop control architecture for the three-phase rectifier to ensure a stable output voltage. The generator-rectifier system rectifier control block diagram is as follows: Figure 4 As shown, the voltage outer loop output signal serves as the reference current component of the d-axis current loop, and the q-axis current reference value is 0, meaning that the rectifier is controlled to output only active current to reduce reactive power loss and improve energy utilization efficiency.

[0089] In this embodiment, the feedback coordination control module samples the generator terminal three-phase voltage in real time during the sampling process of the generator-rectifier system. and three-phase current ,pass Transformation and The transformation converts the voltage and current in the three-phase stationary coordinate system into components in the dq coordinate system. For use in voltage and current dual closed-loop control, and the resulting d-axis voltage component Reference value for current feedforward component in load current feedforward circuit The calculation ensures that the current feedforward component matches the required form of the converter control loop. The calculation method is as follows:

[0090] First of all, Assuming the output power is 0, based on the power balance relationship where the DC power on the rectifier output side and the AC power on the input side are approximately equal, we can obtain:

[0091]

[0092] Furthermore, the feedforward component of the current inner loop reference value The calculation method is shown in the following formula:

[0093]

[0094] To achieve stable voltage control, the outer control loop is a voltage loop that acquires the DC bus voltage in real time. And compared with the preset bus voltage reference value The comparison shows that the output active current reference value, after being adjusted by a proportional-integral (PI) controller, is based on the fundamental component. As shown in the following formula:

[0095]

[0096] in, The d-axis signal output from the outer voltage loop is used as the base current component for the inner current loop reference value. This is the voltage loop proportionality coefficient. The voltage loop integral coefficient, This is the reference value for the DC bus voltage. This is the measured value of the DC bus voltage.

[0097] The inner current loop input of the three-phase rectifier is the dq-axis reference current, and its input signal is shown in the following formula:

[0098]

[0099] Among them, the base component of the current reference value output by the outer voltage loop is... Reference value corresponding to the low-frequency feedforward component of the load current The two values ​​are superimposed and together constitute the active current reference value of the inner current loop. , The reference value of the q-axis current in the inner current loop is used. The difference between the reference value of the dq-axis current and the current measurement value in the sampling loop is calculated. The modulation signal is obtained through PI regulation and current decoupling. Through the fast adjustment of the rectifier, the low-frequency component generated by the sudden change of load current is responded to in a timely manner, reducing the impact of the sudden change of current on the DC bus voltage.

[0100] Meanwhile, overcurrent and overvoltage protection modules are designed for the rectifier. When the output current exceeds 1.3 times the rated current or the DC bus voltage exceeds 1.2 times the voltage reference value, the current loop output command is automatically reduced until the system returns to normal operation, thus preventing damage to the generator-rectifier system due to abnormal operating conditions.

[0101] For energy storage systems, the feedback coordination control module in this embodiment uses a current loop for control. The control block diagram of the energy storage system is as follows: Figure 5 As shown. The current reference value connected to the current control loop of the energy storage system is... This reference value is calculated using the high-frequency component of the load current feedforward. This utilizes the fast response speed and high adjustment accuracy of the battery and its matching DC converter to quickly offset the impact of high-frequency current surges caused by load changes on the DC bus voltage.

[0102] First, since the load current is on the bus side, i.e. the output side of the energy storage converter, the current needs to be converted to the input side for power balance. The relationship obtained according to power conservation is as follows:

[0103]

[0104] in, and These represent the input voltage and current of the DC-DC converter in the energy storage system, respectively. and These represent the output voltage and current of the DC-DC converter in the energy storage system, respectively.

[0105] Obtain the coefficient for the output current to be referred to the input current. :

[0106]

[0107] This refers to the input voltage of the DC-DC converter in the energy storage system. This refers to the output voltage of the DC-DC converter in the energy storage system.

[0108] Obtain the reference current value connected to the control loop of the energy storage system. The calculation formula is as follows:

[0109]

[0110] Furthermore, the reference current is dynamically limited to prevent overcharging and discharging from damaging the battery, while ensuring the effectiveness of the feedforward compensation. The limiting formula is as follows:

[0111]

[0112] in, and These are the maximum allowable output current and the maximum allowable input current of the battery, respectively, and their values ​​are affected by the battery's state of charge (SOC).

[0113] Furthermore, the difference between the current reference value and the measured value is used to obtain the desired modulation signal through a PI controller. The corresponding current loop adjustment formula is shown below:

[0114]

[0115] in, , These are the proportional coefficient and integral coefficient of the current loop, respectively. This is the current reference value, corresponding to the high-frequency component of the load current. The current on the energy storage device side is d, and the calculation result d is used as the PWM modulation reference signal output by the current control loop.

[0116] The operation flowchart of the energy storage system is as follows: Figure 6 As shown, the process of combining current limiting and current loop control yields the following steps:

[0117] Step 1: Obtain the system load current i load .

[0118] Step 2: Through coefficients and , Will Extracting the actual current components that need to be processed in the current loop .

[0119] Step 3: When When, the reference current value remains unchanged; when At that time, the reference current value is ;otherwise The reference current value is .

[0120] Step 4: Input the current reference value into the current loop to obtain the output modulation signal d. Based on the modulation signal... Control the energy storage system.

[0121] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other embodiments.

Claims

1. A shipboard integrated electric power system based on load current feedforward, characterized in that, include: The generator-rectifier system is connected to the DC bus as the main power source; The energy storage system is connected to the DC bus and serves as a compensation device for the main power supply. The load power supply system is connected to the DC bus through a corresponding load converter; The microgrid controller is connected to the generator-rectifier system, the energy storage system, and the load power supply system, respectively. The microgrid controller includes: The acquisition module is used to obtain the total load current of the load power supply system; The frequency divider module is used to decompose the total load current into low-frequency and high-frequency components. The feedback coordination control module is used to send the low-frequency component as a feedforward quantity to the generator-rectifier system and the high-frequency component as a feedforward quantity to the energy storage system.

2. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The method for sending the low-frequency component as a feedforward quantity to the generator-rectifier system in the feedback coordination control module is as follows: The d-axis and q-axis reference currents are: in, Based on the fundamental current component, the current component introduced by the low-frequency component is... This is the measured value of the DC bus voltage. Let be the d-axis component of the generator's three-phase terminal voltage in a rotating coordinate system. The low-frequency component; A dual closed-loop control architecture of voltage and current is adopted for the rectifier in the generator-rectifier system. Without changing the outer voltage loop, the d-axis and q-axis reference currents are input into the inner current loop to control the generator-rectifier system.

3. The shipboard integrated power system based on load current feedforward according to claim 2, characterized in that, Fundamental current components for: in, This is the voltage loop proportionality coefficient. The voltage loop integral coefficient, This is the reference value for the DC bus voltage. Indicates time.

4. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, In the feedback coordination control module, the method for sending the high-frequency component as a feedforward quantity to the energy storage system includes: Through the high frequency components The converted current reference value was calculated. for: in, This refers to the input voltage of the DC-DC converter in the energy storage system. This refers to the output voltage of the DC-DC converter in the energy storage system. For the current reference value Dynamic amplitude limiting: in, and These are the maximum allowable output current and the maximum allowable input current of the battery, respectively. The current reference value after limiting The input is fed into the current control loop to control the energy storage system.

5. The shipboard integrated power system based on load current feedforward according to claim 4, characterized in that, Current reference value The modulation signal is input into the current control loop. : in, This is the proportional coefficient of the current control loop. The integral coefficient of the current control loop. Indicates the current on the energy storage device side. Indicates time; According to the modulation signal Control the energy storage system.

6. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The method for obtaining the total load current of the load power supply system in the acquisition module is as follows: A low-pass filter is used to remove high-frequency interference near the switching frequency, and the current after interference removal is used for load current feedback. : Among them, the angular frequency of the low-pass filter , The cutoff frequency, and , The frequency of the pulse load, This represents the switching frequency.

7. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The low-frequency component is: The high-frequency component is: This is the total load current. , As the frequency division point, It is a complex frequency.

8. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The generator-rectifier system includes a generator, an L-type filter, a three-phase rectifier, and a filter capacitor; the three-phase AC output terminal of the generator is connected in series with the input terminal of the L-type filter, and the output terminal of the L-type filter is electrically connected to the AC input side of the three-phase rectifier; the DC output side of the three-phase rectifier is connected in parallel with the filter capacitor, and the two ends of the filter capacitor are connected to the DC bus. The transmission of electrical energy between the generator-rectifier system and the DC bus is controlled according to the low-frequency component.

9. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The energy storage system includes a battery pack, a bidirectional Buck / Boost converter, an input-side filter capacitor, and an output-side filter capacitor. The positive and negative terminals of the battery pack are connected in parallel with the low-voltage side of the bidirectional Buck / Boost converter, and an input-side filter capacitor is connected in parallel between the battery pack and the bidirectional Buck / Boost converter. The high-voltage side of the bidirectional Buck / Boost converter is connected in parallel with an output-side filter capacitor, and the two ends of the output-side filter capacitor are connected to the DC bus. The bidirectional Buck / Boost converter employs a current control loop to control the bidirectional transmission of electrical energy between the battery pack and the DC bus based on the high-frequency components.

10. The shipboard integrated power system based on load current feedforward according to claim 1, characterized in that, The load power supply system includes at least one of the following: a propulsion motor system, a pulse load power supply system, an AC load power supply system, and a DC load power supply system.

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