Battery charging system, battery charging control method, and battery charging control device

Abstract

The present invention makes it possible to appropriately manage power output from a plurality of power generation modules. Therefore, in a battery charging system (100), a battery charging control device (6, 7) is provided with: a main control unit (21) that increases the output power of a converter (3) in a main module (30M) as a result of subtracting a battery voltage (Vb), which is the voltage of a battery (52), from a predetermined battery voltage command value (Vb *), increases; and a secondary control unit (22-k) that causes the power output by each secondary module (30S) to approach the respective corresponding secondary power command value (Pk *).

Description

Technical Field

[0001] The present invention relates to a battery charging system, a battery charging control method and a battery charging control device. Background Art

[0002] As background art in this technical field, the following Patent Documents 1 and 2 describe techniques for managing power output from a plurality of power supply devices.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-298330

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-055839 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In the above-mentioned technology, there is a desire to more appropriately manage the power output from a plurality of power supply devices (power generation modules).

[0009] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a battery charging system, a battery charging control method, and a battery charging control device capable of appropriately managing power output from a plurality of power generation modules.

[0010] Solutions to Problems

[0011] To solve the above problems, the battery charging system of the present invention is characterized by comprising: a plurality of power generation modules, each of the plurality of power generation modules including an engine, a generator driven by the engine, and a converter for converting a voltage output from the generator into a charging voltage and supplying the converted voltage to a battery to be charged; and a battery charging control device for controlling the power generation modules, the battery charging control device including: a function allocation unit for selecting one of the power generation modules as a primary module and selecting one or more of the power generation modules other than the primary module for charging the battery as secondary modules based on a predicted charging power, which is power predicted to be supplied to the battery; a power command unit for outputting a secondary power command value, which is a command value for power generated by each of the secondary modules; a primary control unit for increasing the output power of the converter of the primary module as the result of subtracting a battery voltage, which is the voltage of the battery, from a predetermined battery voltage command value, increases; and a secondary control unit for adjusting the power output of each of the secondary modules to approach the corresponding secondary power command value.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to appropriately manage the power output from a plurality of power generation modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a block diagram showing the structure of a distributed battery charging system according to a first embodiment.

[0015] Figure 2 This is a diagram showing an example of battery voltage and charging current.

[0016] Figure 3 It is a block diagram of a computer.

[0017] Figure 4 This is a diagram showing an example of a fuel consumption map of an engine.

[0018] Figure 5 is a block diagram of a control system of a sub-controller in a comparative example.

[0019] Figure 6 This is a block diagram of the control system in the first embodiment.

[0020] Figure 7 This is a block diagram of the main control unit.

[0021] Figure 8 This is a block diagram of the secondary control unit.

[0022] Figure 9 This is a flowchart of the main control process.

[0023] Figure 10 This is a flowchart of the sub-control process.

[0024] Figure 11 This is a diagram showing an example of charging power and fuel efficiency in the first embodiment.

[0025] Figure 12 It is a block diagram of a control system in the second embodiment. DETAILED DESCRIPTION

[0026] [Overview of Embodiments]

[0027] As energy decarbonization progresses and renewable energy expands, the importance of regulating power generation systems using renewable energy-derived fuels such as hydrogen (hereinafter referred to as RE fuels) is increasing in order to cope with power fluctuations. Large-scale gas-fired power plants can be used to regulate power, but their output regulation range is often limited to a range of 30% to 100% of rated operation, which cannot achieve sufficient regulation. In addition, since large-scale thermal power generation equipment is installed in a fixed location, power lines need to be strengthened, which increases equipment costs. Furthermore, since the procurement range of fuel used by large-scale thermal power generation equipment is limited, it is difficult to effectively utilize RE fuel that is widely available in the region.

[0028] Distributed power generation systems using engine generators compatible with RE fuels hold great promise as systems that utilize RE fuels that are ubiquitous in a region and can cope with fluctuations in renewable energy. In particular, by utilizing existing mass-produced engines, such as automotive and industrial engines, and combining multiple of them for a stationary power generation system, initial equipment costs can be minimized. Furthermore, electric vehicles (EVs) are expected to increase in number as one of the loads for these engine-generated power systems. The batteries installed in EVs are generally lithium-ion batteries (high-energy-density storage batteries). These new batteries have a wide range of output variations, from a high output range at the beginning of charging to a low output range at the end of charging, and require highly precise voltage control.

[0029] Therefore, in a power generation system using the aforementioned engine as a driving source, it is preferable to first perform fuel-efficient power generation from the engine's high output range to its low output range. Applying the technology of Patent Document 1 above is believed to enable system operation while utilizing the most efficient operating point possible. Specifically, in a vehicle power supply system, if low-cost power supply such as regenerative power can be used, it is believed that increasing its utilization rate can reduce average electricity costs. This technology is believed to suppress frequent battery charging and discharging while effectively utilizing inexpensive power generated by regenerative power generation and other means.

[0030] Furthermore, by applying the technology of Patent Document 2, it is conceivable that a power supply system can be constructed comprising multiple power supply units and an integrated control unit capable of comprehensively controlling each power supply unit in accordance with the total power generation request. Specifically, it is conceivable that at least one of the multiple power supply units can be selected and the voltage control unit of the selected power supply unit can be controlled so that the selected power supply unit generates power at a maximum power level less than the total power generation request at the generator speed. This technology is conceivable to operate multiple power supply units using generators with reduced energy consumption, allowing the multiple power supply units to generate power corresponding to the total power generation request.

[0031] Among the above-mentioned technologies, the technology of patent document 1 is a technology that aims to increase the power of the load to reduce energy consumption in an operating state with good power consumption, that is, in a regenerative state, in a power supply system. Therefore, when the engine efficiency (fuel consumption) of the engine generator is intended to be improved during power generation, it is difficult to achieve this goal. In addition, the technology of patent document 2 is a technology that controls the voltage of the storage devices connected to a plurality of power supply devices respectively. Therefore, in a power generation system in which a specific battery is controlled by a plurality of power generation modules, it is difficult to achieve the goal of charging the battery with high precision while efficiently operating each power generation module. Therefore, the embodiment described below provides a control device that achieves high power generation efficiency and high-precision charging of the connected batteries in a distributed charging system including a plurality of engine power generation modules.

[0032] [First embodiment]

[0033] <Hardware Configuration of First Embodiment>

[0034] Figure 1 is a block diagram showing the structure of a distributed battery charging system 100 according to the first embodiment.

[0035] exist Figure 1 In the distributed battery charging system 100, a switching connection unit 4, a master controller 7 (charging control device), and multiple (n) power generation modules 30-1 to 30-n are included. In the following description, multiple components, information, etc. with the same or similar functions or meanings may be denoted by appending a "-" and alphanumeric characters to the same reference numerals, such as in "power generation modules 30-1, 30-2." However, when it is not necessary to distinguish between these multiple components, the "-" and alphanumeric characters may be omitted, such as in "power generation module 30."

[0036] The distributed battery charging system 100 is connected to a battery 52 and a battery controller 54. The battery 52 can be a battery used in power equipment or a mobile device such as an electric vehicle. The voltage of the battery 52 is referred to as the battery voltage Vb, and the current supplied from the distributed battery charging system 100 to the battery 52 is referred to as the charging current Ib. The product of these two is referred to as the charging power Pb. The battery controller 54 measures the battery voltage Vb, the charging current Ib, and other various battery 52 conditions and supplies the results to the main controller 7.

[0037] The power generation modules 30-1 to 30-n respectively include engines 1-1 to 1-n, generators 2-1 to 2-n, converters 3-1 to 3-n (AC / DC converters), and sub-controllers 6-1 to 6-n (charging control devices). The switching connection unit 4 selects one or more power generation modules 30 and supplies the power output from the selected power generation modules 30 to the battery 52. ​​The battery controller 54 performs various controls on the battery 52.

[0038] Each sub-controller 6 sends and receives various command signals and status signals with the main controller 7 in its upper-level system. Furthermore, the main controller 7 controls and monitors the switching and connection status of the power generation modules 30 by communicating with the switching and connection unit 4. Furthermore, the main controller 7 establishes communication with the battery controller 54. Thus, the main controller 7 continuously collects data such as the specifications and charge status of the battery 52 from the battery controller 54 and executes control corresponding to the charge status of the battery 52. ​​The battery 52 is, for example, a lithium-ion battery.

[0039] Figure 2 1 is a diagram showing an example of the battery voltage Vb and the charging current Ib.

[0040] When the battery 52 (refer to Figure 1 ) is charged, the sub-controller 6 and the main controller 7 charge the battery 52 in the CC charging mode during the initial CC (Constant Current) charging period. Figure 2 In the example shown, the period from time t0 to t1 is the CC charging period. During this period, the charging current Ib matches the predetermined limit current value Im (e.g., the rated current), and the charging power is relatively high. Subsequently, the battery voltage Vb gradually approaches the predetermined battery voltage command value Vb*, i.e., the charging completion voltage.

[0041] Next, when the battery voltage Vb reaches the battery voltage command value Vb*, the sub-controller 6 and the main controller 7 charge the battery 52 in the CV (Constant Voltage) charging period using the CV charging mode. Figure 2 In the example shown in FIG1 , the period after time t1 is the CV charging period. During this period, sub-controller 6 and main controller 7 control charging current Ib so that battery voltage Vb is maintained at battery voltage command value Vb*. Therefore, during the CV charging period, the charging power is relatively low, and charging current Ib gradually decreases over time.

[0042] Figure 3 is a block diagram of computer 980. Figure 1 The sub-controller 6, main controller 7 and battery controller 54 shown include one or more Figure 3The computer 980 shown.

[0043] In Figure 3 the computer 980 includes a CPU 981, a storage unit 982, a communication I / F (interface) 983, an input / output I / F 984, and a medium I / F 985. Here, the storage unit 982 includes a RAM 982a, a ROM 982b, and a HDD 982c. The communication I / F 983 is connected to a communication circuit 986. The input / output I / F 984 is connected to an input / output device 987. The medium I / F 985 reads and writes data from and to a recording medium 988.

[0044] In the ROM 982b, an IPL (Initial Program Loader) and the like to be executed by the CPU are stored. In the HDD 982c, a control program and various data are stored. The CPU 981 realizes various functions by executing the control program and the like read from the HDD 982c into the RAM 982a. The internal structures such as the sub-controller 6 and the main controller 7, which will be described later (refer to Figure 6 , Figure 7 , Figure 8 ) show the functions realized by the control program and the like as blocks.

[0045] Figure 4 is a diagram showing an example of the fuel consumption map of the engine 1.

[0046] For example, diesel engines and the like used in the industrial field and the transportation field have Figure 4 characteristics like the fuel consumption map shown. Moreover, the engine 1 in the present embodiment (refer to Figure 1 ) also has the same characteristics.

[0047] In Figure 4 the horizontal axis is the engine speed and the vertical axis is the torque. In Figure 4 the contour lines H1 to H7 are lines connecting the operating points with the same fuel consumption (fuel consumption), and the fuel consumption related to these contour lines has the relationship of H1 < H2 < H3 < H4 < H5 < H6 < H7. As shown in the figure, at the operating points with high output, the tendency for fuel consumption to decrease is strong, and at the operating points with low output, the tendency for fuel consumption to increase is strong.

[0048] Details will be described later, but in the present embodiment, it is intended to make each engine 1 of the power generation modules 30 generate electricity at an operating point near the optimal fuel consumption, so that the efficiency of the entire system approaches the highest value. Here, as Figure 2As shown, during CV charging, the charging current Ib gradually decreases. If a single power generation module 30 were used to generate the required power for charging, fuel efficiency would increase in the later stages of charging, resulting in unnecessary fuel consumption. In contrast, the distributed battery charging system 100 of this embodiment can utilize the optimal combination of power generation modules 30 for the required charging current Ib. Consequently, the distributed battery charging system 100 can consistently generate power at near-optimal fuel efficiency throughout the entire charging period.

[0049] <Comparative Example>

[0050] Here, before describing the operation of the first embodiment, a comparative example will be described.

[0051] The hardware configuration of the comparative example is the same as that of the first embodiment (see Figure 1 However, in this comparative example, the main controller 7 and the switching connection unit 4 only select the power generation module 30 of any one system and connect it to the battery 52.

[0052] Figure 5 : is a block diagram of the control system of the sub-controller 6 in the comparative example.

[0053] The sub-controller 6 of the comparative example includes a voltage control unit 10 , a current limiting unit 11 , and a current control unit 12 .

[0054] The voltage control unit 10 subtracts the battery voltage Vb from the battery voltage command value Vb*, which is the battery voltage Vb when the battery 52 is fully charged, and outputs a larger current request value Ir as the subtraction result increases. The current limiting unit 11 outputs a current target value It. When the current request value Ir exceeds a predetermined limit current value Im, the current target value It is the limit current value Im, and otherwise, the current request value Ir. Here, the limit current value Im is as follows: Figure 2 As shown, for example, is the rated current value of the charging current Ib.

[0055] The current control unit 12 outputs the current command value Ic* to the converter 3 (see Figure 1 ), the current command value Ic* makes the charging current Ib close to the current target value It. The converter 3 outputs a current corresponding to the current command value Ic* to the battery 52. ​​When the battery voltage Vb is relatively low, that is, when the SOC (State of Charge) is low, the current request value Ir (see Figure 5 ) becomes larger, but since the current target value It is limited by the current limiting unit 11, the current target value It is equal to the limit current value Im. Figure 5 ) performs CC charging mode control.

[0056] That is, the current control unit 12 outputs the current command value Ic* to the converter 3 so as to realize the current target value It output by the current limiting unit 11 = the limit current value Im. Thereafter, charging is continued, and if the battery voltage Vb rises and the SOC becomes higher, the battery voltage Vb eventually reaches the battery voltage command value Vb* (see Figure 2 ). Thus, if the current request value Ir decreases, the current target value It and the current request value Ir are made consistent, and the control of the sub-controller 6 shifts to the CV charging mode.

[0057] As described above, in this comparative example, only the power generation module 30 of any one system is connected to the battery 52 via the switch connection unit 4. This is because when multiple power generation modules 30 are connected to the battery 52 via the switch connection unit 4, the control system of each power generation module 30 is generated (see Figure 5 ) interference, the possibility of pulsation in the charging power.

[0058] (Control System of First Embodiment)

[0059] Figure 6 This is a block diagram of the control system in the first embodiment.

[0060] The main controller 7 includes an information acquisition section 71 , a function allocation section 72 , a power instruction section 74 , and an output variation suppression section 76 .

[0061] The information acquisition section 71 acquires various information from the power generation modules 30 - 1 to 30 - n and the battery controller 54 .

[0062] In addition, the function allocation unit 72 selects at least two power generation modules 30 from among all power generation modules 30 for charging the battery 52. Figure 6 In the example shown, all power generation modules 30-1 to 30-n are selected as power generation modules 30 for supplying charging. Furthermore, the function allocation unit 72 selects one of the power generation modules 30 for supplying charging as the master module 30M and selects the other power generation modules 30 as the slave modules 30S. In the example shown, power generation module 30-1 is selected as the master module 30M, and the other power generation modules 30-k (where 2 ≤ k ≤ n) are selected as the slave modules 30S.

[0063] Here, as charging of the battery 52 progresses, the charging current Ib that can be supplied to the battery 52 gradually decreases. Therefore, the function allocation unit 72 reduces the number of secondary modules 30S in response to the decrease in charging current Ib. Furthermore, the function allocation unit 72 also has the function of setting any secondary module 30S as the new primary module 30M if the primary module 30M stops for some reason.

[0064] The power command unit 74 calculates a predicted charging power Pbest (not shown), which is a predicted value of the charging power Pb, based on the capacity of the battery 52, the current battery voltage Vb, the charging current Ib, the charging rate, and the like. Furthermore, the power command unit 74 calculates a predicted main power Pmest (not shown), which is a predicted value of output power that will achieve good (less than a predetermined threshold) fuel efficiency, based on the engine fuel efficiency characteristic data DE from the main module 30M.

[0065] The power command unit 74 subtracts the predicted main power Pmest from the predicted charging power Pbest to determine the total secondary power command value Psa*, which is the sum of the powers that all the secondary modules 30S should generate. The power command unit 74 then distributes the total secondary power command value Psa* to each of the secondary modules 30S. Figure 6 In the example, secondary power command values ​​Pk* are allocated to the power generation modules 30-k (where 2≤k≤n), and are determined as command values ​​of power output by each power generation module 30-k.

[0066] In other words, the total slave power command value Psa* is the sum of the slave power command values ​​Pk*. When determining the slave power command value Pk* for each slave module 30S, the power command unit 74 determines the slave power command value Pk* based on the engine fuel consumption characteristic data DE so as to achieve good fuel consumption (below a predetermined threshold value).

[0067] If the output of any power generation module 30 decreases for some reason, the output variation suppression unit 76 increases the output of the other power generation modules 30 or designates any power generation module 30 that is not outputting power as a new slave module 30S. Thus, the output variation suppression unit 76 suppresses changes in the charging power supplied to the battery 52.

[0068] The sub-controller 6 of the main module 30M, that is, the sub-controller 6-1 in the illustrated example, is called the main controller 6M, and the sub-controller 6 in the secondary module 30S, that is, the sub-controller 6-k (where 2≤k≤n) in the illustrated example, is called the secondary controller 6S.

[0069] The sub-controllers 6-1 to 6-n store engine fuel consumption characteristic data DE-1 to DE-n related to the engines 1-1 to 1-n they control. The engine fuel consumption characteristic data DE is a fuel consumption diagram (see FIG. 1 ) that describes the fuel consumption of the engine 1 in a table or the like. Figure 4 Each sub-controller 6 supplies the engine fuel consumption characteristic data DE of the local engine to the main controller 7.

[0070] The main controller 6M includes a main setting unit 18 and a main control unit 21. In other words, when the power generation module 30-1 is designated as the main module 30M, the sub-controller 6-1 serving as the main controller 6M activates the functions of the main setting unit 18 and the main control unit 21.

[0071] Furthermore, the secondary controller 6S, or sub-controller 6-k (where 2 ≤ k ≤ n), includes a secondary setting unit 19-k and a secondary control unit 22-k. Specifically, when the power generation module 30-k is designated as the secondary module 30S, the sub-controller 6-k, acting as the secondary controller 6S, activates the functions of the secondary setting unit 19-k and the secondary control unit 22-k.

[0072] Figure 7 2 is a block diagram of the main control unit 21 .

[0073] exist Figure 7 In FIG. 1 , main control unit 21 includes voltage control unit 212 (main voltage control unit), current limiting unit 214 (main current limiting unit), current calculation unit 215 (addition current calculation unit), adder 216, and current control unit 218 (main current control unit). Voltage control unit 212 subtracts battery voltage Vb from battery voltage command value Vb* and outputs a larger main current request value Irm as the subtraction result increases.

[0074] In addition, the current limiting unit 214 outputs the main current target value Itm. When the main current request value Irm exceeds the limit current value Im (see Figure 2 ), the main current target value Itm is the limited current value Im; otherwise, it is the main current request value Irm. The current calculation unit 215 outputs a current addition command value Iad based on the total secondary power command value Psa* and the battery voltage Vb. This current addition command value Iad is an estimated value of the sum of the output currents of the secondary modules 30S.

[0075] Adder 216 adds main current target value Itm to current addition command value Iad and outputs the result as charging current command value Ib*. Current control unit 218 outputs main current command value Icm* to converter 3-1 so that charging current Ib approaches charging current command value Ib*.

[0076] As a result, converter 3-1 outputs a current corresponding to main current command value Icm*. In other words, main control unit 21 has a function that increases the output power of main module 30M as the result of subtracting battery voltage Vb from battery voltage command value Vb* increases. Furthermore, since the power output of main module 30M is close to the predicted main power Pmest calculated by power command unit 74, engine 1 of main module 30M achieves good fuel efficiency.

[0077] Figure 8 It is a block diagram of the secondary control unit 22-k.

[0078] exist Figure 8 In the example, the secondary control unit 22-k includes a current calculation unit 222-k (secondary current calculation unit), a current limiter 224-k (secondary current limiter), and a current control unit 228-k (secondary current control unit). The current calculation unit 222-k outputs a secondary current request value Irsk based on the secondary power command value Pk* and the battery voltage Vb. The secondary current request value Irsk is the current value that realizes the secondary power command value Pk*.

[0079] Current limiting unit 224-k outputs a secondary current target value Itsk. When secondary current request value Irsk exceeds limit current value Im, this secondary current target value Itsk is set to limit current value Im; otherwise, it is set to secondary current request value Irsk. Based on output current Ibsk of converter 3-k and secondary current target value Itsk, current control unit 228-k outputs a secondary current command value Icsk* to converter 3-k, such that output current Ibsk approaches secondary current target value Itsk.

[0080] The converter 3-k outputs a current corresponding to the secondary current command value Icsk* to the battery 52. ​​In this manner, the secondary control unit 22-k has a function of making the power outputted by each of the secondary modules 30S approach the corresponding secondary power command value Pk*.

[0081] Figure 9 This is a flowchart of the main control process.

[0082] When the battery 52 and the battery controller 54 are connected to the distributed battery charging system 100 of the present embodiment, the main controller 7 starts the processing of this routine.

[0083] When Figure 9 When the process proceeds to step S12, the information acquisition unit 71 (refer to Figure 6 ) Obtain various information from the battery controller 54 and the sub-controller 6.

[0084] That is, the information acquisition unit 71 acquires the charge completion voltage and the limit current value Im (see Figure 2 Then, the information acquisition unit 71 sets the acquired charge completion voltage as the battery voltage command value Vb*. In addition, the information acquisition unit 71 acquires the engine fuel consumption characteristic data DE for the corresponding engine 1 from each power generation module 30.

[0085] Next, when the process proceeds to step S14, the power command unit 74 calculates the predicted charging power Pbest, which is a predicted value of the charging power Pb, based on the current state of the battery 52. ​​Next, when the process proceeds to step S16 (function allocation process), the function allocation unit 72 allocates functions to the power generation modules 30 based on the predicted charging power Pbest. Specifically, the function allocation unit 72 selects a power generation module to be charged from among all power generation modules 30, selects one of the power generation modules 30 to be charged as the master module 30M, and selects the remaining power generation modules as the slave modules 30S.

[0086] Next, when processing proceeds to step S18 (power command process), the power command unit 74 sets various data for each power generation module 30. Specifically, the power command unit 74 calculates the predicted main power Pmest and subtracts the predicted main power Pmest from the predicted charging power Pbest to determine the total secondary power command value Psa*. The power command unit 74 then distributes the total secondary power command value Psa* to each secondary module 30S to determine the secondary power command value Pk* to achieve good fuel efficiency (below a predetermined threshold).

[0087] Next, the power command unit 74 supplies the total secondary power command value Psa*, the battery voltage command value Vb*, the limit current value Im, and the charging current Ib to the main controller 6M. In addition, the power command unit 74 supplies the secondary power command value Pk* and the limit current value Im to each secondary controller 6S.

[0088] Thereafter, the process returns to step S14 and the processes of steps S14 to S18 are repeated. As the charging current Ib gradually decreases during this process, the function allocating section 72 gradually decreases the number of slave modules 30S in step S16.

[0089] Although not shown, the main controller 7 sequentially determines whether charging of the battery 52 is complete based on whether the charging current Ib is less than a predetermined value. When the charging current Ib is less than the predetermined value, the main controller 7 stops each power generation module 30 via each sub-controller 6.

[0090] Figure 10 This is a flowchart of the sub-control process.

[0091] When the battery 52 and the battery controller 54 are connected to the distributed battery charging system 100 of the present embodiment, the sub-controller 6 starts the processing of this routine.

[0092] When Figure 10 When the process proceeds to step S32, the sub-controller 6 acquires various information from the main controller 7. Next, when the process proceeds to step S34, the sub-controller 6 determines whether this machine is designated as the main controller 6M.

[0093] When the determination is "yes" in step S34, the process proceeds to step S36 (main control process). Figure 9 ), the main controller 7 supplies the total secondary power command value Psa*, the battery voltage command value Vb*, the limit current value Im, and the charging current Ib to the main controller 6M. Therefore, in step S36, the main setting unit 18 sets these parameters to the main control unit 21.

[0094] On the other hand, when it is determined as "No" in step S34, the process proceeds to step S38 (secondary control process). Figure 9 ), the master controller 7 supplies the slave power command value Pk* and the limit current value Im to the slave controller 6S. Therefore, in step S38, the slave setting unit 19-k sets these parameters to the slave control unit 22-k.

[0095] Next, when the process proceeds to step S40 (secondary control process, main control process), the sub-controller 6 performs charging control on the battery 52. ​​That is, in the main controller 6M, through the main control unit 21 (refer to Figure 7 ) algorithm to control the converter 3-1. In addition, in the secondary controller 6S, the secondary control unit 22-k (see Figure 8 ) algorithm to control the converter 3-k.

[0096] After that, the process returns to step S32 and the processes of steps S32 to S40 are repeated. In particular, in this embodiment, since the determination process of step S34 is repeatedly executed, the main controller 7 can appropriately switch the function of the sub-controller 6 to the main controller 6M or the secondary controller 6S.

[0097] Figure 11 This is a diagram showing an example of charging power Pb and fuel efficiency F in the first embodiment.

[0098] exist Figure 11The fuel efficiency FC in the comparative example is also shown by a dotted line. "Fuel efficiency" refers to the amount of electrical energy obtained by using a certain fuel and can be considered the inverse of the above-mentioned "fuel consumption."

[0099] As described above, charging power Pb decreases over time t. Furthermore, in the comparative example where only one power generation module 30 is used, fuel efficiency FC decreases significantly over time. On the other hand, according to the first embodiment, since the function allocation unit 72 reduces the number of power generation modules 30 over time, fuel efficiency F can be maintained at a relatively high level. Furthermore, according to the first embodiment, the control of varying charging power Pb in response to battery voltage Vb is primarily performed solely by the main module 30M. This enables highly precise charging control that suppresses pulsation in charging power Pb.

[0100] [Second embodiment]

[0101] Figure 12 1 is a block diagram of a control system in the second embodiment. In the following description, parts corresponding to those in the first embodiment are sometimes given the same reference numerals, and their descriptions are sometimes omitted.

[0102] In the second embodiment, a power generation module state detection unit 25 connected to the main controller 7 is provided. Other configurations are the same as those of the first embodiment (see Figure 1 、 Figure 6 ).

[0103] The power generation module state detection unit 25 detects the state of each power generation module 30, determines whether a failure has occurred in each power generation module 30, and supplies the result to the main controller 7. As a result, the main controller 7 can appropriately select the power generation module 30 to be operated and the power generation module 30 among them as the master module 30M.

[0104] [Effects of the embodiment]

[0105] As described above, according to the above embodiment, the battery charging system (100) includes: a plurality of power generation modules 30, each of the plurality of power generation modules 30 includes: an engine 1; a generator 2 driven by the engine 1; and a converter 3 that converts a voltage output from the generator 2 into a charging voltage and supplies it to a battery 52 as a charging target; and a battery charging control device (6, 7) that controls the power generation modules 30, and the battery charging control device (6, 7) includes: a function allocation unit 72 that selects a power generation module 30 as a main module 30M based on a predicted charging power Pbest that is power predicted to be supplied to the battery 52, and selects a power generation module 30 other than the power supply module 30M. One or more power generation modules 30 other than the main module 30M for charging the battery 52 serve as slave modules 30S. The power command unit 74 outputs a slave power command value Pk*, which is a command value for the power generated by each slave module (30-k). The main control unit 21 increases the output power of the converter 3 of the main module 30M as the result of subtracting the battery voltage Vb, which is the voltage of the battery 52, from a predetermined battery voltage command value (Vb*) for the main module 30M increases. The secondary control unit 22-k adjusts the output power of each slave module 30S to approach the corresponding slave power command value Pk*. This allows for appropriate management of the power output from multiple power generation modules. Specifically, using multiple power generation modules allows for high power generation efficiency and highly accurate charging of the connected battery 52.

[0106] Furthermore, it is more preferable that the power command unit 74 determines the slave power command value Pk* for each slave module 30S so as to achieve a fuel efficiency below a predetermined threshold value based on the fuel efficiency characteristics (DE) of the generator 2 of each slave module 30S. This allows determination of an appropriate slave power command value Pk* based on the fuel efficiency characteristics (DE).

[0107] Furthermore, the power command unit 74 preferably includes a function for calculating a predicted main power Pmest based on the fuel consumption characteristics (DE) of the generator 2 of the master module 30M, the predicted main power Pmest being a predicted value of the output power of the master module 30M to achieve a fuel consumption below a predetermined threshold; a function for calculating a total secondary power command value Psa*, which is the sum of the secondary power command values ​​Pk*, by subtracting the predicted main power Pmest from the predicted charging power Pbest; and a function for determining a secondary power command value Pk* for the secondary module 30S to achieve a fuel consumption below a predetermined threshold based on the total secondary power command value Psa* and the fuel consumption characteristics (DE) of the generator 2 of each of the secondary modules 30S. Thus, a more appropriate secondary power command value Pk* can be determined based on the fuel consumption characteristics (DE), the predicted main power Pmest, and the predicted charging power Pbest.

[0108] Furthermore, when the master module 30M stops, the function allocation unit 72 preferably sets any of the slave modules 30S as a new master module 30M. This allows the distributed battery charging system 100 to continue operating even if the master module 30M stops for some reason.

[0109] Furthermore, it is more preferable that the battery charging control device (6, 7) further includes an output variation suppressing unit 76. When the output of any power generation module 30 decreases, the output variation suppressing unit 76 suppresses the variation of the charging power supplied to the battery 52 by increasing the output of the other power generation modules 30 or designating any power generation module 30 that is not outputting as a new slave module (30-k). Thus, even if the output of any power generation module 30 decreases, the variation of the charging power supplied to the battery 52 can be suppressed.

[0110] Furthermore, the function allocation unit 72 determines the number of slave modules 30S based on the capacity of the battery 52 and reduces the number of slave modules 30S in response to a decrease in the charging current Ib flowing through the battery 52. ​​This allows an appropriate number of slave modules 30S to be operated in response to a decrease in the charging current Ib.

[0111] Furthermore, it is more preferred that the main control unit 21 includes: a main voltage control unit (212) for outputting a main current request value Irm, wherein the larger the result obtained by subtracting the battery voltage Vb from the battery voltage command value (Vb*), the larger the main current request value Irm; an addition current calculation unit (215) for outputting a current addition command value Iad based on a total secondary power command value Psa* which is the sum of the secondary power command values ​​Pk* and the battery voltage Vb, wherein the current addition command value Iad corresponds to the sum of the currents output by the secondary modules 30S; and a main current limiting unit. (214) outputs a main current target value Itm, which is the limit current value Im when the main current request value Irm exceeds the predetermined limit current value Im, and is the main current request value Irm otherwise; and a main current control unit (218) controls the output current of the converter (3-1) of the main module 30M so that the charging current Ib flowing through the battery 52 approaches the charging current command value (Ib*), which is the sum of the main current target value Itm and the current addition command value Iad. Thus, the main control unit 21 can more appropriately control the output power of the converter 3 of the main module 30M.

[0112] Furthermore, more preferably, the secondary control unit 22-k includes: a secondary current calculation unit (222-k) for calculating a secondary current request value Irsk for each slave module 30S based on a secondary power command value Pk* for each slave module 30S and a battery voltage Vb; a secondary current limiting unit (224-k) for outputting a secondary current target value Itsk, wherein when each secondary current request value Irsk exceeds a limit current value Im, the secondary current target value Itsk is the limit current value Im, and otherwise is the corresponding secondary current request value Irsk; and a secondary current control unit (228-k) for controlling a secondary output current (Ibsk), which is an output current of the converter (3-k) of each slave module 30S, so as to approach each secondary current target value Itsk. Thus, the secondary control unit 22-k can more appropriately control the power output of each slave module 30S.

[0113] [Modifications]

[0114] The present invention is not limited to the above-mentioned embodiments, and various modifications are possible. The above-mentioned embodiments are exemplified embodiments for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to embodiments including all the structures described. In addition, a part of the structure of a specific embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a specific embodiment. In addition, a part of the structure of each embodiment can be deleted, or other structures can be added / replaced. In addition, the control lines and information lines shown in the figures show structures that are considered necessary for the description, and not all the control lines and information lines required on the product are necessarily shown. In fact, it can be considered that almost all the structures are connected to each other. Possible modifications to the above embodiments are, for example, the following modifications.

[0115] (1) Since the hardware of the sub-controller 6 and the main controller 7 in the above embodiment can be realized by a common computer, the execution Figure 9 、 Figure 10 The flowcharts shown, other programs of the various processes described above, and the like are stored in a storage medium (a computer-readable recording medium having the program recorded thereon) or distributed via a transmission path.

[0116] (2) In the above embodiment, Figure 9 、 Figure 10 The processing shown and other aforementioned processing are described as software processing using a program, but part or all of them may be replaced by hardware processing using an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0117] (3) In each of the above-described embodiments, the power command unit 74 determines the predicted main power Pmest (not shown) and the secondary power command value Pk* based on the engine fuel consumption characteristic data DE so as to achieve good fuel consumption (below a predetermined threshold value). However, instead of using the engine fuel consumption characteristic data DE, an output power range that can achieve good fuel consumption (below a predetermined threshold value) may be precalculated for each power generation module 30, and the predicted main power Pmest (not shown) and the secondary power command value Pk* may be determined so as to fall within this output power range.

[0118] (4) In the above embodiment, the limiting current value Im (see Figure 7 ) and the limiting current value Im of each secondary control unit 22-k (refer to Figure 8 ) are the same value. However, these limiting current values ​​Im may also be different values. For example, the rated output current of each power generation module 30 may be set as the limiting current value Im.

[0119] (5) Various processes executed in the above embodiments may be executed by a server computer via a network (not shown), and various data stored in the above embodiments may be stored in the server computer.

[0120] Description of labels

[0121] 1 engine

[0122] 2 generators

[0123] 3 Converters

[0124] 6-sub controller (battery charging control device)

[0125] 7 Main controller (battery charging control device)

[0126] 21 Main Control Department

[0127] 22-k Secondary Control Department

[0128] 30 Power Generation Module

[0129] 30M main module

[0130] 30S secondary module

[0131] 52 batteries

[0132] 72 Function Allocation Department

[0133] 74 Power command unit

[0134] 76 Output variation suppression unit

[0135] 100 distributed battery charging systems (battery charging systems)

[0136] 212 Voltage control unit (main voltage control unit)

[0137] 214 Current limiting unit (main current limiting unit)

[0138] 215 current calculation unit (addition current calculation unit)

[0139] 218 current control unit (main current control unit)

[0140] 222-k current calculation unit (secondary current calculation unit)

[0141] 224-k current limiting unit (secondary current limiting unit)

[0142] 228-k current control unit (secondary current control unit)

[0143] DE engine fuel consumption characteristics data (fuel consumption characteristics)

[0144] Ib charging current

[0145] Im limit current value

[0146] Vb battery voltage

[0147] Pk*Secondary power command value

[0148] Iad Current addition command value

[0149] Irm Main current request value

[0150] Itm Main current target value

[0151] Step S16 (Function Allocation Process)

[0152] Step S18 (Power Instruction Process)

[0153] Step S36 (Main Control Process)

[0154] Step S38 (Secondary Control Process)

[0155] Step S40 (Secondary Control Process, Primary Control Process)

[0156] Psa* Total secondary power command value

[0157] Ibsk output current (secondary output current)

[0158] Irsk Secondary current request value

[0159] Itsk secondary current target value

[0160] Pbest predicted charging power

[0161] Pmest predicts primary power.

Claims

1. A battery charging system, characterized in that: include: a plurality of power generation modules, each of the plurality of power generation modules including an engine, a generator driven by the engine, and a converter for converting a voltage output from the generator into a charging voltage and supplying the voltage to a battery to be charged; as well as A battery charging control device controls the power generation module. The battery charging control device comprises: a function allocation section that selects one of the power generation modules as a primary module and selects one or more of the power generation modules other than the primary module for charging the battery as secondary modules based on predicted charging power that is power predicted to be supplied to the battery; a power instruction unit, outputting a secondary power instruction value, wherein the secondary power instruction value is an instruction value of power generated by each of the secondary modules; a main control unit configured to increase the output power of the converter of the main module as a result of subtracting a battery voltage, which is the voltage of the battery, from a predetermined battery voltage command value increases for the main module; as well as The secondary control unit makes the power output by each of the secondary modules approach the corresponding secondary power command value.

2. The battery charging system according to claim 1, wherein: The power command unit determines the slave power command value of the slave module so as to achieve a fuel consumption equal to or less than a predetermined threshold value based on the fuel consumption characteristics of the generator of each slave module.

3. The battery charging system according to claim 1, wherein: The power command unit includes: a function of calculating a predicted main power based on the fuel consumption characteristics of the generator of the main module, wherein the predicted main power is a predicted value of the output power of the main module when the fuel consumption is below a predetermined threshold; a function of calculating a total secondary power command value as a sum of the secondary power command values ​​by subtracting the predicted primary power from the predicted charging power; and The function is to determine the slave power command value of the slave module for achieving a fuel consumption equal to or less than a predetermined threshold value based on the total slave power command value and the fuel consumption characteristics of the generator of each slave module.

4. The battery charging system according to claim 1, wherein: When the main module stops, the function allocation section sets any one of the secondary modules as the new main module.

5. The battery charging system according to claim 4, wherein: It also includes an output variation suppression unit that suppresses variations in charging power supplied to the battery by increasing the output of the other power generation modules or designating any power generation module that is not outputting as a new secondary module when the output of any of the power generation modules decreases.

6. The battery charging system according to claim 1, wherein: The function allocation unit determines the number of the slave modules according to the capacity of the battery, and then reduces the number of the slave modules in response to a decrease in the charging current flowing through the battery.

7. The battery charging system according to claim 5, wherein: The main control unit includes: a main voltage control unit configured to output a main current request value, wherein the larger the result obtained by subtracting the battery voltage from the battery voltage command value, the larger the main current request value; an addition current calculation unit that outputs a current addition command value corresponding to the total of the currents output by the slave modules based on a total slave power command value that is a sum of the slave power command values ​​and the battery voltage; a main current limiting unit configured to output a main current target value, wherein when the main current request value exceeds a predetermined limit current value, the main current target value is the limit current value, and otherwise is the main current request value; and A main current control unit controls an output current of the converter of the main module so that a charging current flowing through the battery approaches a charging current command value, the charging current command value being a sum of the main current target value and the current addition command value.

8. The battery charging system according to claim 7, wherein: The secondary control unit includes: a secondary current calculation unit for calculating a secondary current request value in each of the secondary modules based on the secondary power command value for each of the secondary modules and the battery voltage; a secondary current limiting unit configured to output a secondary current target value, wherein when each of the secondary current request values ​​exceeds the current limit value, the secondary current target value is the current limit value, and otherwise is the corresponding secondary current request value; as well as The secondary current control unit controls a secondary output current, which is an output current of the converter of each of the secondary modules, so as to approach each of the secondary current target values.

9. A battery charging control method, applied to a battery charging system, the battery charging system comprising: A plurality of power generation modules and a battery charging control device for controlling the power generation modules, wherein each of the plurality of power generation modules includes an engine, a generator driven by the engine, and a converter for converting a voltage output from the generator into a charging voltage and supplying the voltage to a battery to be charged. The battery charging control method includes: a function allocation process of selecting one of the power generation modules as a primary module and selecting one or more of the power generation modules other than the primary module for charging the battery as secondary modules based on a predicted charging power that is power predicted to be supplied to the battery; A power instruction process outputs a secondary power instruction value, wherein the secondary power instruction value is an instruction value of the power generated by each of the secondary modules; a main control process for increasing the output power of the converter of the main module as a result of subtracting the battery voltage, which is the voltage of the battery, from a predetermined battery voltage command value, for the main module; and The secondary control process makes the power output by each of the secondary modules close to the corresponding secondary power command value.

10. A battery charging control device, characterized in that: include: a function allocation unit for controlling a plurality of power generation modules, selecting one power generation module as a primary module and selecting one or more power generation modules other than the primary module for charging the battery as secondary modules based on a predicted charging power that is power predicted to be supplied to the battery, each of the plurality of power generation modules including an engine, a generator driven by the engine, and a converter that converts a voltage output from the generator into a charging voltage and supplies the converted voltage to the battery to be charged; a power instruction unit, outputting a secondary power instruction value, wherein the secondary power instruction value is an instruction value of power generated by each of the secondary modules; a main control unit configured to increase the output power of the converter of the main module as a result of subtracting a battery voltage, which is the voltage of the battery, from a predetermined battery voltage command value increases for the main module; as well as The secondary control unit makes the power output by each of the secondary modules approach the corresponding secondary power command value.

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