Ship direct current networking parallel operation method

Abstract

The invention discloses a ship direct-current networking parallel operation method, which belongs to the technical field of ship power supply, and comprises the following steps that: a main controller receives operation signals of each parallel operation controller and judges the type of a current operation power supply module according to each operation signal, and the main controller enters each operation mode according to the type of the current operation power supply module; the operation modes comprise a generator set parallel operation mode, a power battery pack parallel operation mode and a generator set and power battery pack parallel operation mode; by configuring a multi-mode load distribution scheme in the main controller, the realization of functions of load distribution, energy transfer and the like between the generator sets, between the power battery packs and between the generator sets and the power battery packs can be ensured, and multi-mode parallel connection of the generator sets and the power battery packs can be conveniently and effectively controlled; and the current distribution precision and the bus voltage stabilization capability during parallel operation of multiple power supply modules are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ship power supply, and in particular relates to a ship DC networking and paralleling method. Background Art

[0002] The ship's electric propulsion system has two power distribution methods: AC networking and DC networking. The DC networking power distribution method has the advantages of low loss, high power quality, and efficient energy distribution management, which solves the shortcomings of the AC networking power distribution method such as low energy utilization and slow energy conversion.

[0003] The prior art only describes the control method of parallel connection of two diesel generator sets in a DC network or the parallel connection of power batteries / supercapacitors, and does not involve the control method of parallel connection of generator sets and other power modules such as power batteries. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a ship DC networking and paralleling method, which can ensure the realization of functions such as load distribution and energy transfer between generator sets, between power battery sets, and between generator sets and power battery sets.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A ship DC networking and parallel operation method, comprising: a main controller receives operation signals from each parallel operation controller and determines the type of a currently operating power module according to each operation signal, and the main controller enters each operation mode according to the type of the currently operating power module; the operation modes include a generator set parallel operation mode, a power battery group parallel operation mode and a generator set and power battery group parallel operation mode; when the generator sets are in parallel operation mode, the main controller controls each converter to distribute the load in proportion according to the rated power of each generator set; when the power battery groups are in parallel operation mode, the main controller controls each converter to distribute the load in proportion according to the charge of each power battery group; when the generator sets and power battery groups are in parallel operation mode, according to the daily operation load, the generator sets and the power battery groups distribute the load in proportion to their rated powers, or the generator sets bear fixed loads and the power battery groups are in peak load regulation mode.

[0007] Furthermore, when the main controller distributes the load in proportion to the rated power of each power module, the main controller adopts the voltage-power / current droop mode for primary regulation, and calculates the current signal of each converter and compares it with the average current value and compensates it by the compensation coefficient K1 as secondary regulation.

[0008] Furthermore, the compensation coefficient K1 is calculated as follows:

[0009]

[0010] Among them, ΔI(k) is the current secondary regulation amount of the converter in the i-th power module at the current moment, ΔI(k-1) is the current secondary regulation amount of the converter in the i-th power module at the previous moment, I i (k) is the current signal of the converter in the i-th power module at the current moment, It is the average current of the converters in all power modules at the current moment.

[0011] Furthermore, when the main controller distributes the load in proportion to the charge of each power battery pack, the main controller adopts the voltage-power / current droop mode for primary regulation, and calculates the charge of each converter and compares it with the average charge and compensates it by the compensation coefficient K2 as secondary regulation.

[0012] Furthermore, the compensation coefficient K2 is calculated as follows:

[0013]

[0014] Among them, ΔSOC(k) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the current moment, ΔSOC(k-1) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the previous moment, SOC i (k) is the charge of the converter in the i-th power battery pack at the current moment, It is the average value of the current charge of the converters in all power battery packs.

[0015] Furthermore, in the parallel operation mode of the generator set and the power battery pack, when the daily operating load is greater than the total power of the operable generator set or the total power of the power battery, the power battery pack and the generator set power are distributed according to their rated power ratio; when the daily operating load fluctuates within the set operating load power of the generator set, the generator set bears a fixed load and the power battery pack is in peak-shaving mode.

[0016] Furthermore, the specific way in which the generator set bears a fixed load and the power battery group is in peak-shaving mode is as follows: when the online load is less than or equal to the set operating load of the generator set, the unit carries the load, and the power battery is connected online in parallel, but does not carry the load; when the online load is greater than the set operating load of the generator set, the generator set carries the set operating load, and the remaining load is borne by the power battery group.

[0017] Furthermore, the generator set is set to operate at a load of 75% of the rated power of the generator set.

[0018] After adopting the above technical solution, the beneficial effects of the present invention are:

[0019] Since the ship DC networking parallel operation method of the present invention includes a main controller receiving operation signals of each parallel operation controller and judging the type of the currently operating power module according to each operation signal, the main controller enters each operation mode according to the type of the currently operating power module; the operation mode includes a generator set parallel operation mode, a power battery group parallel operation mode and a generator set and a power battery group parallel operation mode; when the generator set is in parallel operation mode, the main controller controls each converter to distribute the load in proportion according to the rated power of each generator set; when the power battery group is in parallel operation mode, the main controller controls each converter to distribute the load in proportion according to the charge of each power battery group; when the generator set and the power battery group are in parallel operation mode, according to the daily operation load, the generator set and the power battery group distribute the load in proportion to their rated power, or the generator set bears a fixed load and the power battery group is in peak load mode, by configuring a plurality of modes of load distribution schemes, it is possible to ensure the realization of functions such as load distribution and energy transfer between generator sets, between power battery groups and between generator sets and power battery groups, facilitate effective control of multiple modes of parallel connection of generator sets and power battery groups, and improve the current distribution accuracy and bus voltage stabilization capability when multiple power modules are in parallel operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the ship DC networking system;

[0021] Figure 2 It is a schematic diagram of the flow chart of the parallel operation mode of the generator sets of the present invention;

[0022] Figure 3 It is a schematic diagram of the adjustment of the load distribution according to the rated power of the present invention;

[0023] Figure 4 It is a schematic diagram of load regulation according to the load amount of the present invention;

[0024] Figure 5 It is a flow chart of the generator set taking on fixed load and the power battery group in peak load regulation mode;

[0025] In the figure, 1-energy management cabinet, 11-touch screen, 12-main controller, 2-switch, 3-rectifier cabinet 1, 31-parallel controller 1, 32-marine generator set 1, 33-unit monitor 1, 34-rectifier 1, 35-AC circuit breaker 1, 4-rectifier cabinet 2, 41-parallel controller 2, 42-marine generator set 2, 43-unit monitor 2, 44-rectifier 2, 45-AC circuit breaker 2, 5-chopper cabinet 1, 51-parallel controller 3, 52-power battery pack 1, 53-battery management system 1, 54-chopper 1, 55-DC circuit breaker 1, 6-chopper cabinet 2, 61-parallel controller 4, 62-power battery pack 2, 63-battery management system 2, 64-chopper 2, 65-DC circuit breaker 2. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0027] Ship DC networking system powered by ship generator set and power battery pack Figure 1 As shown, the system is described below by taking two generator sets 32, 42 and two power battery sets 52, 62 as examples. The DC networking parallel control system consists of an energy management cabinet (EMS) 1, rectifier cabinets 3, 4, and chopper cabinets 5, 6. The energy management cabinet 1 is equipped with a touch screen 11, a main controller 12, and a switch 2. The main controller 12 uses Siemens CPU1513R13, and the touch screen 11 and the main controller 12 communicate via Modbus RS485.

[0028] The rectifier cabinet 3 is installed with the parallel controller 31, rectifier (AC / DC1) 34, AC circuit breaker 35 and other related devices. The parallel controller 31 controls the start-up and operation of the unit monitoring instrument 33 and the marine generator set 32, and then controls the closing of the AC circuit breaker 35 to transmit the AC power of the generator set 32 ​​to the incoming line terminal of the rectifier 34, and finally controls the rectifier 34 to convert the AC power into DC power and transmit it to the DC bus. The control method set in the parallel controller 31 is used to realize the load distribution function. The rectifier cabinet 4 is installed with the parallel controller 41, rectifier (AC / DC2) 44, AC circuit breaker 45 and other related devices, and its control function and connection method are the same as those in the rectifier cabinet 3.

[0029] The chopper cabinet 5 is equipped with a parallel controller 51, a chopper (DC / DC1) 54, a DC circuit breaker 55 and other related devices. The parallel controller 51 controls the startup and operation of the battery management system 53 and the power battery pack 52, and then controls the DC circuit breaker 55 to transmit the DC power of the power battery pack 52 to the incoming line terminal of the chopper 54, and finally controls the chopper 54 to transmit the DC power to the DC bus after the voltage value of the DC power. The parallel controller 51 collects the power battery pack 52 including SOC, voltage and other related parameters from the battery management system 53 through communication, and sets the control method in the parallel controller 51 to realize the load distribution function. The chopper cabinet 6 is equipped with a parallel controller 61, a chopper (DC / DC2) 64, a DC circuit breaker 65 and other related devices, and its control function and connection method are the same as those in the chopper cabinet 5.

[0030] PN communication is used between the main controller 12 and the parallel controllers 31, 41, 51, 61 to complete data exchange and control, and realize power distribution and scheduling between the generator sets and the power batteries.

[0031] like Figure 2 As shown, a ship DC networking and parallel operation method of the present application includes: a main controller 12 receives operation signals of each parallel operation controller and determines the type of the currently running power module according to each operation signal, and the main controller enters each operation mode according to the type of the currently running power module; the operation mode includes a generator set parallel operation mode, a power battery group parallel operation mode and a generator set and power battery group parallel operation mode.

[0032] When the generator sets are in parallel operation mode, the main controller controls each converter to distribute the load in proportion to the rated power of each generator set. When the power battery packs are in parallel operation mode, the main controller controls each converter to distribute the load in proportion to the charge of each power battery pack. When the generator sets and power battery packs are in parallel operation mode, according to the daily operating load, the generator sets and power battery packs distribute the load in proportion to their rated power, or the generator sets bear fixed loads and the power battery packs are in peak load mode.

[0033] Specifically, in the parallel operation mode of the generator set and the power battery pack, when the daily operation load (i.e., the economic operation load) is greater than the total power of the operable generator set or the total power of the power battery, the power battery pack and the generator set power are distributed according to their rated power ratio. When the daily operation load fluctuates within the power of the generator set's set operation load, the generator set bears a fixed load and the power battery pack is in peak load regulation mode.

[0034] Combine the following Figure 1 And each view describes in detail the control method of each parallel operation mode:

[0035] (1) Figure 2As shown, when the generator sets are in parallel operation mode, or the generator sets and the power battery packs are in parallel operation mode and the power battery packs and the generator set power distribute the load in proportion to their rated power, the generator sets 32 and 42 are connected in parallel, or the generator sets 32, 42 and the power battery packs 52, 62 are connected in parallel, and the main controller 12 controls each inverter, i.e., rectifiers 34, 44, choppers 54, 64 to distribute the load in proportion to the rated power of each power module, i.e., the marine generator sets 32, 42, and the power battery packs 52, 62.

[0036] The calculation formula for distributing the load between the generator sets 32 and 42 is as follows:

[0037]

[0038] P i ′ is the load that the i-th operating power supply should carry, P 在线 is the load currently carried by the DC bus, P i额 is the rated load of the i-th operating power supply.

[0039] like Figure 3 As shown, in this working mode, the main controller 12 adopts the voltage-power / current droop mode for primary regulation, and calculates the current signal of each converter 34, 44, 54, 64 and compares it with the average current value and compensates it by the compensation coefficient K1 as secondary regulation. Specifically, the current I currently borne by the power modules 32, 42, 52, 62 i Or the current power P i Warp sag coefficient K droop Adjustment, compensation by compensation coefficient K1, and finally current / power control.

[0040] In primary regulation, K droop The calculation method is:

[0041] K droop =P i *(U2-U1) / P n ,

[0042] Among them, U2 is the voltage when no load, U1 is the voltage when full load, P n is the rated power, P i is the current power;

[0043] Or, K droop =I i *(U2-U1) / I n ,

[0044] Among them, U2 is the voltage when no load, U1 is the voltage when full load, I n is the rated current, I iis the current currently borne.

[0045] In the secondary adjustment, the compensation coefficient K1 is calculated as follows:

[0046]

[0047] Among them, ΔI(k) is the current secondary regulation amount of the converter in the i-th power module at the current moment, ΔI(k-1) is the current secondary regulation amount of the converter in the i-th power module at the previous moment, I i (k) is the current signal of the converter in the i-th power module at the current moment, It is the average current of the converters in all power modules at the current moment.

[0048] (2) When in the power battery pack parallel operation mode, the power battery packs 52 and 62 are connected in parallel, and the main controller 12 controls each converter, namely the chopper 54 and 64 to distribute the load in proportion to the charge of each power battery pack 52 and 62 .

[0049] like Figure 4 As shown, in this working mode, the main controller uses the voltage-power / current droop mode for primary regulation, and uses the calculation of the charge of each converter and the average charge to compare and compensate by the compensation coefficient K2 as the secondary regulation. Specifically, the current I currently borne by the power module i Or the current power P i Warp sag coefficient K droop Adjustment, compensation by compensation coefficient K2, and finally current / power control. In this working mode, the droop coefficient K droop Droop factor K in parallel operation with generator sets droop Consistent.

[0050] In the secondary adjustment, the compensation coefficient K2 is calculated as follows:

[0051]

[0052] Among them, ΔSOC(k) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the current moment, ΔSOC(k-1) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the previous moment, SOC i (k) is the charge of the converter in the i-th power battery pack at the current moment, It is the average value of the current charge of the converters in all power battery packs.

[0053] When the power battery packs are operated in parallel, the SOCs of the n power battery packs are different. When the energy management cabinet 1 distributes the load, the SOCs of the power battery packs are introduced to ensure that the performance of the power batteries operated in parallel remains consistent. After a period of load operation according to the above method, the SOCs of the two power battery packs will tend to be consistent and the output will be uniform.

[0054] (3) When the generator sets 32 and 42 are in parallel operation mode with the power battery sets 52 and 62, and the daily operating load fluctuates within the power set of the generator set, the generator sets 32 and 42 bear the fixed load and the power battery sets 52 and 62 are in peak load regulation mode.

[0055] like Figure 5 As shown, the specific way in which the generator set bears a fixed load and the power battery group is in peak-shaving mode is: when the online load is less than or equal to the set operating load of the generator set, the unit carries the load, and the power battery is connected online in parallel, but does not carry the load; when the online load is greater than the set operating load of the generator set, the generator set carries the set operating load, and the remaining load is borne by the power battery group.

[0056] The operating load setting of the generator set can be set according to work experience and needs, such as 70% to 90% of the rated power of the generator set. The present application preferably sets the operating load of the generator set to 75% of the rated power of the generator set.

[0057] The ship DC networking and parallel operation method of the present invention configures multiple modes of load distribution schemes through the main controller, which can ensure the realization of functions such as load distribution and energy transfer between generator sets, between power battery sets, and between generator sets and power battery sets, facilitates effective control of multiple modes of parallel connection of generator sets and power battery sets, and improves the current distribution accuracy and bus voltage stabilization capability when multiple power modules are operated in parallel.

[0058] In the description of this specification, unless otherwise clearly defined, words such as "setting", "installation", and "connection" should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention based on the specific content of the technical solution.

[0059] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the described embodiments are only some embodiments of the present invention, rather than all embodiments, which are merely examples, and the protection scope of the present invention is defined by the claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention and without any creative work, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for paralleling DC networks for ships, characterized in that: include: The main controller receives the operation signals of each parallel controller and determines the type of the currently running power module according to each operation signal, and the main controller enters each operation mode according to the type of the currently running power module; The operation modes include a generator set parallel operation mode, a power battery pack parallel operation mode, and a generator set and power battery pack parallel operation mode; When the generator sets are in parallel operation mode, the main controller controls each converter to distribute the load in proportion to the rated power of each generator set; When the power battery packs are in parallel operation mode, the main controller controls each converter to distribute the load in proportion to the charge of each power battery pack; When the generator set and the power battery pack are in parallel operation mode, the generator set and the power battery pack distribute the load in proportion to their rated power according to the daily operating load, or the generator set bears a fixed load and the power battery pack is in peak load regulation mode.

2. The ship DC networking and paralleling method according to claim 1, characterized in that: When the main controller distributes the load in proportion to the rated power of each power module, the main controller adopts the voltage-power / current droop mode for primary regulation, and calculates the current signal of each converter and compares it with the average current value and compensates it by the compensation coefficient K1 as secondary regulation.

3. The ship DC networking and paralleling method according to claim 2, characterized in that: The calculation method of the compensation coefficient K1 is: Among them, ΔI(k) is the current secondary regulation amount of the converter in the i-th power module at the current moment, ΔI(k-1) is the current secondary regulation amount of the converter in the i-th power module at the previous moment, I i (k) is the current signal of the converter in the i-th power module at the current moment, It is the average current of the converters in all power modules at the current moment.

4. The ship DC networking and paralleling method according to claim 1, characterized in that: When the main controller distributes the load in proportion to the charge of each power battery pack, the main controller adopts the voltage-power / current droop mode for primary regulation, and calculates the charge of each converter and compares it with the average charge and compensates it by the compensation coefficient K2 as secondary regulation.

5. The ship DC networking and paralleling method according to claim 4, characterized in that: The compensation coefficient K2 is calculated as follows: Among them, ΔSOC(k) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the current moment, ΔSOC(k-1) is the charge secondary adjustment amount of the converter in the i-th power battery pack at the previous moment, SOC i (k) is the charge of the converter in the i-th power battery pack at the current moment, It is the average value of the current charge of the converters in all power battery packs.

6. The ship DC networking and paralleling method according to any one of claims 1 to 5, characterized in that: In the parallel operation mode of the generator set and the power battery pack, when the daily operating load is greater than the total power of the operable generator set or the total power of the power battery, the power battery pack and the generator set power are distributed according to their rated power ratio; when the daily operating load fluctuates within the set operating load power of the generator set, the generator set bears a fixed load and the power battery pack is in peak load regulation mode.

7. The ship DC networking and paralleling method according to claim 6, characterized in that: The specific way in which the generator set bears a fixed load and the power battery pack is in peak-shaving mode is as follows: when the online load is less than or equal to the set operating load of the generator set, the unit carries the load and the power battery is connected online in parallel but does not carry the load; when the online load is greater than the set operating load of the generator set, the generator set carries the set operating load and the remaining load is borne by the power battery pack.

8. The ship DC networking and paralleling method according to claim 7, characterized in that: The generator set is set to operate at a load of 75% of the rated power of the generator set.

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