Power supply

Abstract

To provide a power source device in which the operational time can be increased and the frequency of input / output restrictions can be reduced while a circuit component is thermally protected.SOLUTION: A power source device according to the present invention includes a plurality of power storage units that are connected in parallel to an input / output power line via at least one reactor element and at least one switching element. The power source device includes a calculation unit that calculates, as a limit power amount of each of the power storage units, an amount of power that can be inputted to / outputted from the power storage unit on the basis of the temperature of the reactor element and / or the temperature of the switching element, and a control unit that distributes a requested input / output power amount to the plurality of power storage units on the basis of the differential value between the average remaining capacity of the plurality of power storage units and the remaining capacity of each of the power storage units, calculates an excess power amount and a power shortage amount of each of the power storage units on the basis of the differential value between the requested input / output power amount distributed to the power storage unit and the limited power amount of the power storage unit, and redistributes the total value of the power shortages of the power storage units, to a power storage unit having an excess power amount.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply device. [Background technology]

[0002] Patent Document 1 describes a control method for controlling multiple input / output adjustment devices electrically connected between multiple batteries and a load, thereby giving priority to outputting power from a battery with a higher State Of Charge (SOC) than the overall average SOC during powering (and vice versa during regeneration). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 220906 Summary of the Invention [Problem to be solved by the invention]

[0004] In the control method described in Patent Document 1, even if the temperature of the circuit components constituting the power supply device becomes high, the power output continues, which may cause overheating and burnout. On the other hand, if the power output is stopped to prevent overheating and burnout, the operation of the entire power supply device will stop.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a power supply device that can increase the operating time and reduce the frequency of input / output restrictions while protecting circuit components from heat. [Means for solving the problem]

[0006] The power supply device of the present invention is a power supply device having a plurality of storage units connected in parallel to input / output power lines via at least one reactor element and switching element, and is equipped with a calculation unit that calculates, for each storage unit, the amount of power that the storage unit can input / output as a limited power amount based on the temperature of at least one of the reactor element and the switching element, and a control unit that distributes the required input / output power amount among the plurality of storage units based on the difference value between the average remaining capacity of the plurality of storage units and the remaining capacity of each storage unit, calculates the power margin and power deficit of each storage unit from the difference value between the required input / output power amount distributed to each storage unit and the limited power amount of the corresponding storage unit, and redistributes the total value of the power deficit of each storage unit to the storage unit with a power margin. Effect of the Invention

[0007] According to the power supply device of the present invention, the required input / output power amount is redistributed among a plurality of power storage units in consideration of the limited power amount of the power storage unit calculated based on the temperature of at least one of the reactor element and the switching element, so that it is possible to increase the operating time and reduce the frequency of input / output restrictions while providing thermal protection to the circuit components. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a power supply system according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing the flow of power control processing according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram for explaining the distribution process of the total power request amount after upper and lower limit restrictions. [Figure 4] FIG. 4 is a diagram showing an example of a map that defines the relationship between the element temperature and the load factor of the battery pack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration and operation of a power supply system according to an embodiment of the present invention will be described with reference to the drawings.

[0010] 〔composition〕 First, with reference to FIG. 1, a configuration of a power supply system according to an embodiment of the present invention will be described.

[0011] Fig. 1 is a schematic diagram showing the configuration of a power supply system according to one embodiment of the present invention. As shown in Fig. 1, the power supply system 1 according to one embodiment of the present invention includes a power supply device 2, temperature sensors 3(N) (N=1 to n), and a control device 4.

[0012] The power supply device 2 includes a plurality (n pieces) of battery packs 21(N) (N=1 to n) that can be charged and discharged, such as lithium ion secondary batteries, nickel hydrogen secondary batteries, and capacitors. The battery packs 21(N) function as a power storage unit according to the present invention. The plurality of battery packs 21(N) may be the same battery, capacitor, or the like, or may be different types of batteries, capacitors, or the like. However, when different types of batteries, capacitors, or the like are used, the control device 4 performs control described later taking into consideration differences in the electrical characteristics of the batteries, such as capacity and voltage. Furthermore, even when the same battery, capacitor, or the like is used, when the battery packs have different degrees of deterioration, the control device 4 performs control described later taking into consideration the differences in the degrees of deterioration.

[0013] Each battery pack 21(N) is connected in parallel to bus bars L1, L2 that are connected to a load 5 and a system 6 via switching elements 22(N), 23(N) and a reactor element (inductor element) 24(N). The bus bars L1, L2 function as input / output power lines according to the present invention. A smoothing capacitor C and a reactor element R for smoothing the power flowing between the power supply device 2 and the control device 4 are connected between the bus bars L1 and L2. The switching elements 22(N), 23(N) are composed of semiconductor switching elements.

[0014] Here, an IGBT (Insulated Gate Bipolar Transistor) is used as the semiconductor switching element. A diode (rectifier element) is connected between the collector terminal and emitter terminal of the IGBT, with the side connected to the emitter terminal as the anode. When a semiconductor switching element other than an IGBT is used, a diode is connected in parallel to the semiconductor switching element so that a current flows in the opposite direction to the current that flows when the switching element is conductive. The diode may be a parasitic diode associated with the semiconductor switching element. In this specification, the combination of a semiconductor switching element and a diode is called a switching element.

[0015] A smoothing capacitor 25(N) that smoothes the power flowing between the switching elements 22(N), 23(N) and the battery pack (N) is connected in parallel to each battery pack 21(N). A positive electrode side relay is connected to the positive electrode of each battery pack 21(N), and a negative electrode side relay is connected to the negative electrode. A resistive element and a precharge relay connected in series are connected in parallel to the negative electrode side relay. This allows the smoothing capacitor 25(N) to be precharged by controlling the on / off of these relays at a predetermined timing, such as at startup.

[0016] The temperature sensor 3(N) detects the temperatures of the switching elements 22(N), 23(N) and the reactor element 24(N), and outputs an electrical signal indicating the detected temperatures to the control device 4. Note that the temperature sensor 3(N) may be configured to detect the temperature of only one of the switching elements 22(N), 23(N) and the reactor element 24(N).

[0017] The control device 4 is composed of an information processing device such as an ECU (Electronic Control Unit), and an arithmetic processing device within the information processing device executes a computer program to control the operation of the entire power supply system 1. Specifically, the control device 4 controls the on / off of switching elements 22(N), 23(N) of the power supply device 2 to charge the battery pack 21(N) using power supplied from the system 6 and to supply the charging power of the battery pack 21(N) to the load 5. The control device 4 functions as a calculation unit and a control unit according to the present invention.

[0018] In the power supply system 1 having such a configuration, the control device 4 executes the power control process described below, thereby achieving an increase in operating time and a reduction in the frequency of input / output restrictions while providing thermal protection to the switching elements 22(N), 23(N) and the reactor element 24(N). Hereinafter, the operation of the control device 4 when executing the power control process according to one embodiment of the present invention will be described with reference to Fig. 2.

[0019] [Power control processing] Fig. 2 is a flowchart showing the flow of the power control process according to one embodiment of the present invention. The flowchart shown in Fig. 2 starts when an output request signal or an input request signal is input from the load 5 or the system 6 to the control device 4, and the power control process proceeds to step S1.

[0020] In the process of step S1, the control device 4 detects the temperatures of the switching elements 22(N), 23(N) and the reactor element 24(N) using the temperature sensor 3(N), and calculates the amount of power that the corresponding battery pack 21(N) can input or output based on the detected temperature as the limited power amount Win'(N) / Wout'(N). Specifically, the control device 4 calculates the limited power amount Win'(N) / Wout'(N) of each battery pack (N) so as to reduce the amount of power that can be input or output as the temperature of the switching elements 22(N), 23(N) and the reactor element 24(N) increases. Then, the control device 4 calculates the sum of the limited power amounts Win'(N) / Wout'(N) of each battery pack (N) as the total limited power amount Win' / Wout', which is the amount of power that can be input or output by the entire power supply device 2. This completes the process of step S1, and the power control process proceeds to the process of step S2.

[0021] In the process of step S2, the control device 4 calculates a total power request amount after upper and lower limit restrictions, which restricts the upper and lower limits of the total power request amount from the loads 5 or the grid 6 according to the total limited power amount Win' / Wout' calculated in the process of step S1. This completes the process of step S2, and the power control process proceeds to the process of step S3.

[0022] In the process of step S3, the control device 4 distributes the total power request amount after upper and lower limit restrictions calculated in the process of step S2 among the battery packs (N) based on the difference between the remaining capacity (or voltage) of the battery pack 21(N) and the average remaining capacity of the entire power supply device 2. Specifically, during discharging, as shown in Fig. 3 for example, if the average SOC of the entire power supply device 2 is higher than the SOC of the battery pack 21(N), the control device 4 sets the output coefficient k(N) of the battery pack 21(N) to be larger than a predetermined value (average value) kav, and if the average SOC of the entire power supply device 2 is smaller than the SOC of the battery pack 21(N), the control device 4 sets the output coefficient k(N) of the battery pack 21(N) to be smaller than the predetermined value kav. Similarly, when charging, the control device 4 sets the input coefficient of the battery pack 21(N) to be smaller than a predetermined value (average value) when the average SOC of the entire power supply device 2 is larger than the SOC of the battery pack 21(N), and sets the input coefficient of the battery pack 21(N) to be larger than a predetermined value when the average SOC of the entire power supply device 2 is smaller than the SOC of the battery pack 21(N). Then, the control device 4 calculates the power distribution amount (input / output power amount) Win(N) / Wout(N) of each battery pack (N) by multiplying the value k(N) / Σk(N) obtained by dividing the output coefficient k(N) (or input coefficient) by the sum Σk(N) of the output coefficients k(N) (or input coefficients) by the total power request amount after upper and lower limit restrictions. This completes the process of step S3, and the power control process proceeds to the process of step S4.

[0023] In the process of step S4, the control device 4 calculates the load factor I(N) of the battery pack 21(N) corresponding to the temperature of the switching elements 22(N), 23(N) and the reactor element 24(N) detected in the process of step S1 by using a map that defines the relationship between the element temperature and the load factor I(N) of the battery pack 21(N) as shown in FIG. 4. In the map shown in FIG. 4, the relationship between the element temperature and the load factor I(N) of the battery pack 21(N) is defined so that the load factor I(N) decreases when the element temperature becomes equal to or higher than a predetermined temperature T1, and becomes zero when the element temperature becomes equal to or higher than a predetermined temperature T2. Then, the control device 4 calculates the upper and lower limit limited power distribution amount by multiplying the power distribution amount Win(N) / Wout(N) calculated in the process of step S3 by the load factor I(N). This completes the process of step S4, and the power control process proceeds to the process of step S5.

[0024] In the process of step S5, the control device 4 calculates the power margin and power shortage for each battery pack 21(N) from the difference between the power distribution amount Win(N) / Wout(N) calculated in the process of step S3 and the power distribution amount after upper and lower limit restrictions calculated in the process of step S4. Then, the control device 4 calculates the total value of the power shortage amounts of each battery pack 21(N) as the total power shortage amount, and redistributes the insufficient power amount (additional burden power amount) to the battery packs 21(N) having the power margin in ascending order of the power margin so as to reduce the total power shortage amount. Note that the control device 4 may equally redistribute the insufficient power amount to the battery packs 21(N) having the power margin. With this, the process of step S5 is completed, and the power control process proceeds to the process of step S6.

[0025] In the process of step S6, the control device 4 controls each battery pack 21(N) to input and output the amount of power after the process of step S5. This completes the process of step S6, and the series of power control processes ends.

[0026] As is clear from the above explanation, in the control processing which is one embodiment of the present invention, the control device 4 calculates, for each battery pack 21(N), the amount of power that the battery pack 21(N) can input or output as the limited power amount based on the temperatures of the switching elements 22(N), 23(N) and the reactor element 24(N), distributes the requested input / output power amount between the battery packs 21(N) based on the difference between the average SOC of the battery packs 21(N) and the remaining capacity of each battery pack 21(N), calculates the power margin and power deficit of each battery pack 21(N) from the difference between the requested input / output power amount distributed to each battery pack 21(N) and the limited power amount of the corresponding battery pack 21(N), and redistributes the total value of the power deficit of each battery pack 21(N) to the battery pack 21(N) with a power margin.

[0027] That is, the control device 4 redistributes the requested input / output power amount between the battery packs 21(N) in consideration of the limited power amount of the battery pack 21(N) calculated based on the temperatures of the switching elements 22(N), 23(N) and the reactor element 24(N). This makes it possible to increase the operating time and reduce the frequency of input / output restrictions while providing thermal protection to the switching elements 22(N), 23(N) and the reactor element 24(N). The control device 4 may calculate the limited power amount of the battery pack 21(N) based on the temperature of one of the switching elements 22(N), 23(N) and the reactor element 24(N).

[0028] Although the embodiments of the invention made by the present inventors have been described above, the present invention is not limited by the descriptions and drawings that form part of the disclosure of the present invention according to the present embodiments. In other words, other embodiments, examples, operation techniques, etc. made by those skilled in the art based on the present embodiments are all included in the scope of the present invention. [Explanation of symbols]

[0029] 1 Power System 2 Power supply 3(N) Temperature sensor 4. Control device 5. Load 6 lines 21(N) Battery pack 22(N), 23(N) Switching element 24(N) Reactor element 25(N) smoothing capacitor L1,L2 busbar

Claims

[Claim 1] A power supply device including a plurality of power storage units connected in parallel to an input / output power line via at least one reactor element and a switching element, a calculation unit that calculates an amount of power that can be input / output to / from each power storage unit as a limited amount of power based on a temperature of at least one of the reactor element and the switching element, and calculates a total value of the limited amounts of power of each power storage unit as an overall limited amount of power that is an amount of power that can be input / output to / from the entire power supply device; calculating a total power request amount after upper and lower limit restrictions by restricting upper and lower limits of a total power request amount from a load or a system in accordance with the total limited power amount, calculating a power distribution amount of each power storage unit by multiplying a value obtained by dividing an output coefficient or an input coefficient by a sum of an output coefficient or an input coefficient, and distributing the total power request amount after upper and lower limit restrictions among the power storage units in accordance with the power distribution amount of each power storage unit; calculating a load factor of the power storage unit corresponding to the temperatures of the switching element and the reactor element using a map that defines the relationship between element temperature and the load factor of the power storage unit, and multiplying the power distribution amount of each power storage unit by the load factor to calculate a post-upper / lower limit restricted power distribution amount that restricts upper and lower limit values ​​of the power distribution amount for each power storage unit; a control unit that calculates a power margin and a power deficit for each power storage unit from a difference between the power distribution amount of each power storage unit and the power distribution amount after the upper and lower limits are restricted, calculates a total value of the power deficit amounts of each power storage unit as an overall power deficit, and redistributes the amount of power that is in deficit to the power storage units having a power margin so as to reduce the overall power deficit; A power supply device comprising:

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