JP2022023722A - Conversion device, power storage module, and power supply system - Google Patents

Abstract

To provide a technique that achieves electric power transfer between power storage batteries with a power conversion device having a relatively small output capacity.SOLUTION: In a power distribution system, a conversion device 120 for transferring electric power between a plurality of storage batteries 110, 116, includes: first terminal pairs 124 connected to one storage battery of the plurality of storage batteries; second terminal pairs 126 connected to another storage battery of the plurality of storage batteries; and an insulated conversion circuit 122 which has third terminal pairs 128 and fourth terminal pairs 130, and provides DC output of input of DC power into one of the third terminal pairs and the fourth terminal pairs to the other terminal pairs by controlling a voltage or a current. The first terminal pairs and the third terminal pairs are connected in parallel, and the first terminal pairs and the fourth terminal pairs are serially connected. The first terminal pairs and the fourth terminal pairs, which are serially connected, are connected with the second terminal pairs in parallel.SELECTED DRAWING: Figure 2

Description

The present invention relates to a converter, a power storage module and a power supply system.

For example, Patent Document 1 obtains a charging / discharging device capable of preventing electric power from moving between a power storage battery included in an electric vehicle and a stationary storage battery and suppressing a loss due to the movement of electric power. Disclosed are inventions relating to a charging / discharging device and a charging / discharging system for the purpose of this. In the present invention, a charge / discharge system is configured together with a charge / discharger for a storage battery that charges a stationary storage battery installed in a house and discharges the stationary storage battery to supply power to a load, and is provided in an electric vehicle. A charging / discharging device that performs a charging operation of a power storage battery and a discharging operation of discharging the power storage battery to supply power to the load, and detects the value of the current flowing between the stationary storage battery and the load. The control unit includes a control unit that controls the charging operation of the power storage battery and the discharging operation of the power storage battery based on the value of the current detected by the current detection unit. Based on the value of the current, it is determined whether or not power transfer occurs between the power storage battery and the stationary storage battery, and if the power transfer occurs, the operation of the charge / discharge device is changed. Has been done. The control unit stops the charging operation when the power transfer occurs and the charging / discharging device is executing the charging operation, the power transfer occurs, and the charging / discharging device performs the discharging operation. It is said that the discharge operation is stopped when it is being executed.

For example, Patent Document 2 aims to suppress battery deterioration in an electric vehicle such as an EV, maintain vehicle performance for a long period of time, and reduce the cost burden of a user due to battery replacement. The invention relating to the control device is disclosed. In the present invention, as a battery for driving an electric vehicle, a main battery that has a large capacity and is used in an area of small deterioration narrower than the normal SOC usage range, and a small capacity and an upper limit value of the normal SOC usage range. It is equipped with a sub-battery that is used within the range between the lower limit values, and power is appropriately transferred between the main battery and the sub-battery so that the SOC of the main battery becomes a suitable value from the viewpoint of extending the life. , The sub-battery is premised on regular replacement, and the SOC setting value of the sub-battery is set to give priority to the life of the main battery. As a result, the incidental cost increases by the amount of the sub-battery installed, but it is said that the life cost of the system as a whole will be reduced and the burden on the user will be reduced by extending the life of the main battery. It is said that a power transfer means for transferring power between a main battery and a sub battery is provided, and a DCDC converter is disclosed as the power transfer means.

For example, Patent Document 3 discloses a control method for a hybrid vehicle drive control device and a hybrid vehicle drive device, which aims not only to reduce the weight of the hybrid vehicle but also to reduce the cost of the hybrid vehicle. And the invention relating to the program. In the present invention, a first battery, a second battery, a voltage conversion member that converts a voltage between a first power supply voltage of the first battery and a second power supply voltage of the second battery, and a voltage conversion member. When the battery environment detector for detecting the battery environment and the predetermined battery among the first and second batteries are placed under the predetermined battery environment, power is transferred from one battery to the other battery. It is said to have a power transfer processing means 91. In this case, when a predetermined battery among the first and second batteries is placed in a predetermined battery environment, power is transferred from one battery to the other battery, so that the other battery is sufficient. It is said that it can be discharged. A DC / DC converter is disclosed as the voltage conversion member.

Japanese Patent No. 6548854 Japanese Unexamined Patent Publication No. 2014-147197 Japanese Patent Application Laid-Open No. 2003-299210

By using the inventions disclosed in Patent Documents 1 to 3, it is possible to transfer electric power from one storage battery to another storage battery in two or more storage batteries (batteries). However, when transferring power, it is necessary to control the voltage or current of at least one of the storage battery at the source or the storage battery at the destination, and a power converter capable of such control, for example, a DC / DC converter is required. Become.

However, the above-mentioned power conversion device (DC / DC converter) requires an output capacity according to the amount of power to be handled. For example, when moving power at 1 kW, a power conversion device having an output capacity of 1 kW is used. is necessary. A power conversion device corresponding to such a large power capacity is generally expensive, and there is a problem that the product cost is high.

Further, there is a problem that the efficiency is limited by the performance of the power conversion device. For example, in a power conversion device having a maximum efficiency of 95%, there is a problem that the power of a storage battery cannot be transferred with an efficiency of 95% or more.

An object of the present invention is to provide a technique for realizing power transfer between storage batteries by a power conversion device having a relatively small output capacity. Another object of the present invention is to provide a technique for improving the efficiency of power transfer between storage batteries.

In order to solve the above problems, in the first aspect of the present invention, it is a conversion device for transferring electric current between a plurality of storage batteries, and is connected to one of the plurality of storage batteries. It has one terminal pair, a second terminal pair connected to another storage battery among the plurality of storage batteries, a third terminal pair and a fourth terminal pair, and one of the third terminal pair and the fourth terminal pair. It has an isolated conversion circuit that controls the voltage or current of the DC power input to the terminal pair and outputs the DC power to the other terminal pair, and the first terminal pair and the third terminal pair are in parallel. A conversion in which the first terminal pair and the fourth terminal pair are connected in series, and the first terminal pair and the fourth terminal pair connected in series and the second terminal pair are connected in parallel. Disclose the device.

The terminal voltage V1 of the first terminal pair is lower than the terminal voltage V2 of the second terminal pair (V1 <V2), and the storage battery connected to the first terminal pair is connected to the second terminal pair. In the conversion circuit, one end of the fourth terminal pair connected to the negative voltage side of the first terminal pair is a positive voltage, the other end is a negative voltage, and the third terminal pair is an input terminal. The first configuration is such that the fourth terminal pair functions as an output terminal, the terminal voltage V1 of the first terminal pair is higher than the terminal voltage V2 of the second terminal pair (V1> V2), and the first terminal pair. When attempting to transfer power from a storage battery connected to a terminal pair to a storage battery connected to the second terminal pair, the fourth terminal pair connected to the negative voltage side of the first terminal pair in the conversion circuit. A second configuration in which one end serves as a negative electrode and the other end serves as a positive electrode, the third terminal pair functions as an output terminal, and the fourth terminal pair functions as an input terminal. The terminal-to-terminal voltage V1 of the first terminal pair is the second terminal pair. When the voltage between terminals of the terminal pair is higher than V2 (V1> V2) and power is to be transferred from the storage battery connected to the second terminal pair to the storage battery connected to the first terminal pair, in the conversion circuit, One end of the fourth terminal pair connected to the negative voltage side of the first terminal pair is a negative voltage, the other end is a positive voltage, the third terminal pair functions as an input terminal, and the fourth terminal pair functions as an output terminal. 3 or the terminal voltage V1 of the first terminal pair is lower than the terminal voltage V2 of the second terminal pair (V1 <V2), and the first terminal from the storage battery connected to the second terminal pair. When trying to transfer power to a storage battery connected to a pair, in the conversion circuit, one end of the fourth terminal pair connected to the negative voltage side of the first terminal pair is used as a positive voltage and the other end is used as a negative voltage. It may have any of a fourth configuration, in which the three terminal pair functions as an output terminal and the fourth terminal pair functions as an input terminal.

Further, the inrush current suppressing means for suppressing the inrush current that may occur when the storage battery is connected to the first terminal pair or the second terminal pair is further provided, and the inrush current suppressing means is connected to the connected terminal pair to be connected. It is a switch mechanism arranged between the connected storage battery to be connected, and after controlling the voltage between the terminals of the connected terminal pair to match the output voltage of the connected storage battery in the conversion circuit, the switch mechanism is operated. The first configuration, which is turned on, is feedback in which the inrush current suppressing means feedback-controls the current meter that measures the current flowing through the connected storage battery and the conversion circuit so that the measured value of the current meter gradually increases or decreases. The second configuration or the inrush current suppressing means having the circuit is a DC power conversion device similar to the conversion device, and the series connection voltage between the DC power conversion device and the connection storage battery is connected to the DC power conversion device. It may have any of the third configurations, which control the DC power conversion device so as to match the voltage between the terminals of the terminal pair.

The first terminal pair or the second terminal pair may connect a plurality of storage batteries connected in parallel to each other. In this case, corresponding to each of the plurality of storage batteries, the rush current suppressing means for suppressing the rush current that may occur when one of the plurality of storage batteries is added is further provided, and the rush current suppressing means will be added. It is a switch mechanism arranged between the connected terminal pair to be added and the connected storage battery to be added, and controls the voltage between the terminals of the connected terminal pair to match the output voltage of the connected storage battery in the conversion circuit. After that, the first configuration for turning on the switch mechanism or the inrush current suppressing means is a DC power conversion device similar to the conversion device, and the DC power conversion device and the connected storage battery are connected in series. It may have any of the second configurations, which control the DC power conversion device so that the connection voltage matches the voltage between the terminals of the connected terminal pair.

The watt-hour meter that measures the amount of power output from the first terminal pair or the second terminal pair and the amount of power that is output when the measured value of the watt-hour meter reaches a predetermined value becomes zero. Further, a control device for controlling the conversion circuit can be provided. In addition, the control device can output billing information according to the amount of output power. The billing information may be calculated by determining the unit price of the unit electric energy and multiplying the output electric energy by the unit price. Further, regarding the amount of power output from the first terminal pair or the second terminal pair, it is decided to move a certain amount of power at regular time intervals, and billing information is calculated from the moved time. May be good.

In the second aspect of the present invention, there is provided a power storage module having the above-mentioned conversion device and a single or a plurality of storage batteries connected to the first terminal pair or the second terminal pair.

In the third aspect of the present invention, the DC power distribution device for supplying DC power from the DC power source to the DC load and the above-mentioned power storage module are provided, and surplus power is stored in the power storage module to reduce insufficient power. A power supply system supplied from the power storage module is provided. As the DC power source, a DC power generation device such as a solar cell can be exemplified.

In the fourth aspect of the present invention, a DC distribution device that supplies DC power from a DC power source to a DC load, and a conversion device for transferring DC power from the DC distribution device to a single or a plurality of storage batteries. , The conversion device receives DC power from the DC distribution device, a first terminal pair, a second terminal pair connected to the single or a plurality of storage batteries, a third terminal pair, and a third terminal pair. An isolated conversion circuit that has four terminal pairs and outputs DC power input to one terminal pair of the third terminal pair and the fourth terminal pair by controlling the voltage or current to the other terminal pair. The second terminal pair and the third terminal pair are connected in parallel, the first terminal pair and the fourth terminal pair are connected in series, and the first terminal pair connected in series is connected. And to provide a power supply system in which the fourth terminal pair and the second terminal pair are connected in parallel.

The power supply system described above further includes an AC / DC converter that receives AC power and converts the received AC power into DC power, and the DC power distribution device comprises the AC DC in addition to the DC power from the DC power source. DC power from the converter may be distributed. The AC power to be received may be, for example, AC power generated by an AC generator or commercial AC power distributed by an electric power company or the like. Further, there may be a plurality of AC / DC converters that receive AC power and convert the received AC power into DC power.

The outline of the above invention does not list all the necessary features of the present invention. A subcombination of these feature groups can also be an invention.

It is a block diagram which shows an example of a power generation and distribution system 100. It is a block diagram which shows the detail of a conversion apparatus 120. It is a circuit diagram which shows an example of a conversion circuit 122. It is a block diagram which shows the conversion apparatus 140. It is a block diagram which shows the conversion apparatus 142. It is a block diagram which shows the conversion apparatus 146. It is a block diagram which shows the detail of a power storage module 150. It is a block diagram which shows the example which a plurality of storage batteries are connected in parallel to the 2nd terminal pair 126 of a conversion apparatus 120. It is a block diagram which shows the example which a plurality of storage batteries are connected in parallel to the 2nd terminal pair 126 of a conversion apparatus 120. It is a block diagram which shows the modification example of the conversion apparatus 120. It is a block diagram which shows an example of a power generation and distribution system 200. It is a block diagram which shows the detail of a conversion apparatus 220. It is a block diagram which shows the conventional connection.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention to which the claims are made. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

(Embodiment 1)
FIG. 1 is a block diagram showing an example of a power generation / distribution system 100. The power generation / distribution system 100 has a power supply system 102, and the power supply system 102 receives power from the DC power supply 104 or the AC power 106 and distributes the DC power to the DC load 108. Further, the power supply system 102 supplies DC power to the second storage battery 110 and receives DC power from the second storage battery 110. Examples of the DC power source include a DC power generation device such as a solar cell. Further, as the AC power 106, for example, commercial AC power received from an electric power company or the like can be mentioned. The AC power 106 is not an essential configuration requirement for the power generation / distribution system 100.

The power supply system 102 includes a DC distribution device 112, an AC / DC conversion device 114, a first storage battery 116, and a conversion device 120. The AC / DC converter 114 receives power from the AC power 106 and converts the received AC power into DC power. The first storage battery 116 stores excess DC power when it is generated, and discharges the stored DC power when a shortage occurs to compensate for the shortage. When the AC power 106 is not received, the AC / DC converter 114 is not an indispensable configuration requirement.

The DC power distribution device 112 supplies DC power from the DC power supply 104 to the DC load 108. When the DC power source 104 is a solar cell, the DC power distribution device 112 has a function of maximizing the output power from the solar cell. When receiving the AC power 106, the DC distribution device 112 integrates the DC power from the DC power supply 104 and the DC power from the AC / DC converter 114 and supplies the DC power to the DC load 108. Further, the DC distribution device 112 supplies surplus power to the first storage battery 116, receives insufficient power from the first storage battery 116, and supplies it to the DC load 108.

FIG. 2 is a block diagram showing details of the conversion device 120. The conversion device 120 is a power conversion device for transferring DC power between a plurality of storage batteries, in this example, between the first storage battery 116 and the second storage battery 110. The conversion device 120 has a conversion circuit 122, a first terminal pair 124 and a second terminal pair 126. The first terminal pair 124 is connected to the first storage battery 116, and the second terminal pair 126 is connected to the second storage battery 110. The first storage battery 116 is an example of one storage battery among a plurality of storage batteries, and the second storage battery 110 is an example of another storage battery among the plurality of storage batteries.

The conversion circuit 122 has a third terminal pair 128 and a fourth terminal pair 130, and a DC power input to one terminal pair of the third terminal pair 128 and the fourth terminal pair 130 is voltageed or transferred to the other terminal pair. Controls the current and outputs DC. The third terminal pair 128 and the fourth terminal pair 130 are insulated from each other. Further, the first terminal pair 124 and the third terminal pair 128 are connected in parallel, the first terminal pair 124 and the fourth terminal pair 130 are connected in series, and the first terminal pair 124 and the fourth terminal pair are connected in series. The 130 and the second terminal pair 126 are connected in parallel.

FIG. 3 is a circuit diagram showing an example of the conversion circuit 122. The conversion circuit 122 is a general bidirectional isolated DCDC converter circuit, and can be a flyback converter circuit. Q1 to Q8 are field effect transistors (FETs), and the parasitic diodes and gate drive circuits of Q1 to Q8 are omitted.

The conversion circuit 122 can step up, step down, and invert the output of the input power by controlling the ON / OFF cycle, the ON / OFF time ratio, and the timing of Q1 to Q8. Further, since the conversion circuit 122 is symmetrical, power is input from the bridge circuit on the right side and power is taken out from the circuit on the left side, and conversely, power is input from the bridge circuit on the left side and the circuit on the right side is used. It is also possible to extract power from. By using the output voltage or output current for feedback, it is possible to obtain a constant voltage output or a constant current output. Similarly, by using the input voltage or input current for feedback, it is possible to keep the input voltage constant or keep the input current constant.

The conversion circuit 122 can be operated, for example, as follows.
-By turning off all of Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8, the circuits on the right and left sides are completely disconnected both in terms of direct current and alternating current.
-By repeating the operation of turning on Q1 and Q4 and turning off Q2 and Q3 and the operation of turning on Q2 and Q3 and turning off Q1 and Q4, a square wave is given to VT1 and the VT1 is passed through a transformer. It is possible to generate an electromotive force in the VT2. At this time, according to the polarity of the voltage of VT2, when the side indicated by "+" becomes a positive voltage, Q6 and Q7 are turned ON, Q5 and Q8 are turned OFF, and the side indicated by "+" is negative. By turning on Q5 and Q8 and turning off Q6 and Q7 when the voltage is reached, T1 can be set to + and T2 can be set to −. By reversing ON / OFF, the polarities of the voltages appearing in T1 and T2 can be reversed.
-Since this circuit is symmetrical, the operations performed in Q1, Q2, Q3, and Q4 are performed in Q5, Q6, Q7, and Q8, and the operations performed in Q5, Q6, Q7, and Q8 are performed in Q1, Q2, and Q3. By performing in Q4, power can be transferred in the opposite direction (from the right side to the left side of the circuit).

The conversion circuit 122 outputs the input to one of the two terminal pairs (third terminal pair 128, fourth terminal pair 130) to the other by voltage control or current control, and is output to the first terminal pair 124, first. By connecting the two-terminal pair 126, the third terminal pair 128, and the fourth terminal pair 130 as described above, the conversion circuit 122 is connected to the first terminal pair 124 or the second terminal pair 126 as an auxiliary power source for the storage battery. It becomes possible to function as. That is, even if the voltage of the first storage battery 116 connected to the first terminal pair 124 and the voltage of the second storage battery 110 connected to the second terminal pair 126 are different, it corresponds to the voltage difference between the two storage batteries. The voltage to be generated is compensated by the conversion circuit 122, and both storage batteries can be safely connected.

Further, by controlling the output voltage or output current of the conversion circuit 122 and controlling which terminal pair of the conversion circuit 122 is used as the input or the output, the charge / discharge (charging direction) between the two storage batteries is controlled. Will be possible.

Table 1 shows each terminal (T1) of the fourth terminal pair 130 (TP4) when the magnitude relationship between the voltage V1 of the first storage battery 116 and the voltage V2 of the second storage battery 110 and the power transfer direction (charging direction) are given. , T2) and a table showing whether the third terminal pair 128 (TP3) and the fourth terminal pair 130 (TP4) function as an input or an output.

The terminal voltage V1 of the first terminal pair 124 is lower than the terminal voltage V2 of the second terminal pair 126 (V1 <V2), and the first storage battery 116 connected to the first terminal pair 124 is connected to the second terminal pair 126. In the case of the configuration 1 in which the DC power is to be transferred (BAT1 → BAT2) to the second storage battery 110, one end (T1) of the fourth terminal pair 130 connected to the negative electrode side of the first terminal pair 124 in the conversion circuit 122. ) Is a positive electrode, the other end (T2) is a negative electrode, the third terminal pair 128 is an input terminal, and the fourth terminal pair 130 is an output terminal.

By operating the conversion circuit 122 in this way, the insufficient voltage of V1 can be supplemented by the conversion circuit 122. That is, the shortage of the voltage required to transfer power from the first storage battery 116 to the second storage battery 110 (the shortage of the output voltage in the first storage battery 116) is the output voltage of the conversion circuit 122 (fourth terminal pair 130 (TP4)). The voltage can be supplemented by the voltage assisted by the conversion circuit 122, so to speak.

The terminal voltage V1 of the first terminal pair 124 is higher than the terminal voltage V2 of the second terminal pair 126 (V1> V2), and the first storage battery 116 connected to the first terminal pair 124 is connected to the second terminal pair 126. In the case of the configuration 2 in which the DC power is to be transferred (BAT1 → BAT2) to the second storage battery 110, one end (T1) of the fourth terminal pair 130 connected to the negative electrode side of the first terminal pair 124 in the conversion circuit 122. ) Is the negative electrode, the other end (T2) is the positive electrode, the third terminal pair 128 is the output terminal, and the fourth terminal pair 130 is the input terminal.

By operating the conversion circuit 122 in this way, it is possible to reduce the voltage of V1 that is too high by the conversion circuit 122 and at the same time return the reduced power (do not move the power corresponding to the reduced power). .. As a result, the electric power can be transferred from the first storage battery 116 to the second storage battery 110 without waste.

The terminal voltage V1 of the first terminal pair 124 is higher than the terminal voltage V2 of the second terminal pair 126 (V1> V2), and the second storage battery 110 connected to the second terminal pair 126 is connected to the first terminal pair 124. In the case of the configuration 3 in which the DC power is to be transferred (BAT2 → BAT1) to the first storage battery 116, one end (T1) of the fourth terminal pair 130 connected to the negative electrode side of the first terminal pair 124 in the conversion circuit 122. ) Is the negative electrode, the other end (T2) is the positive electrode, the third terminal pair 128 is used as an input terminal, and the fourth terminal pair 130 is used as an output terminal.

By operating the conversion circuit 122 in this way, the output voltage of the conversion circuit 122 can be added to the voltage of V2, and the insufficient voltage of V2 can be supplemented by the conversion circuit 122. In the case of this configuration 3, the output of the conversion circuit 122 (power output from the fourth terminal pair 130 (TP4)) is the input of the conversion circuit 122 (power input to the third terminal pair 128 (TP3)). Since it is used as a part, the power from the second storage battery 110 is not supplied to the input of the conversion circuit 122 until the output of the conversion circuit 122 is started. Even in such a case, the first storage battery 116 Since the power from is supplied to the input of the conversion circuit 122, the operation is started without any particular problem. After the operation of the conversion circuit 122, the power from the second storage battery 110 is supplied to the input of the conversion circuit 122 (third terminal pair 128 (TP3)), and the DC power is transferred to the first storage battery 116.

The terminal voltage V1 of the first terminal pair 124 is lower than the terminal voltage V2 of the second terminal pair 126 (V1 <V2), and the second storage battery 110 connected to the second terminal pair 126 is connected to the first terminal pair 124. In the case of the configuration 4 for transferring DC power (BAT2 → BAT1) to the first storage battery 116, one end (T1) of the fourth terminal pair 130 connected to the negative electrode side of the first terminal pair 124 in the conversion circuit 122. ) Is a positive electrode, the other end (T2) is a negative electrode, the third terminal pair 128 is an output terminal, and the fourth terminal pair 130 is an input terminal.

By operating the conversion circuit 122 in this way, the voltage of V2 that is too high can be reduced by the conversion circuit 122, and at the same time, the reduced power can be combined and transferred to the first storage battery 116.

By making the conversion circuit 122 function as in any of the above configurations 1 to 4, even if there is a difference between the voltage V1 of the first storage battery 116 and the voltage V2 of the second storage battery 110, the voltage difference (| V1-V2 |), and realizes power transfer from the first storage battery 116 to the second storage battery 110 (BAT1 → BAT2) or power transfer from the second storage battery 110 to the first storage battery 116 (BAT2 → BAT1). The conversion device 120 can be controlled.

Further, by using the conversion device 120, the efficiency of power transfer from the first storage battery 116 to the second storage battery 110 (BAT1 → BAT2) or power transfer from the second storage battery 110 to the first storage battery 116 (BAT2 → BAT1) can be improved. Can be enhanced.

For example, in the case of configuration 1 (V1 <V2, BAT1 → BAT2), T1 functions as a positive electrode, T2 functions as a negative electrode, the fourth terminal pair 130 functions as an output, and the third terminal pair 128 functions as an input. Assuming that the total power output from the first storage battery 116 is P1, the input power of the conversion circuit 122 is P3, the output power of the conversion circuit 122 is P4, and the power supplied to the second storage battery 110 is P2.
P2 = P1-P3 + P4 ... (Equation 1)
Here, if the efficiency of the conversion circuit 122 is X, then P3 × X = P4, and if X is transferred to the right side, then
P3 = P4 / X ... (number 2)
Substituting the number 2 into the number 1 and setting η = (1-X) / X,
P2 = P1-η × P4
P1 = P2 + η × P4 ... (number 3)
On the other hand, since the efficiency E of the power transfer (BAT1 → BAT2) from the first storage battery 116 to the second storage battery 110 is E = P2 / P1, the equation 3 is substituted.
E = P2 / (P2 + η × P4) ... (Equation 4)
Assuming that the current flowing on the fourth terminal pair 130 side of the conversion circuit 122 is I, P2 = V2 × I, P4 = V4 × I, V4 = V2-V1, so if it is substituted into equation 4,
E = (V2 × I) / (V2 × I + η × (V2-V1) × I)
= 1 / (1 + η × (1-V1 / V2)) ... (Equation 5)
Will be.

As specific numerical values, for example, the voltage V1 = 300V of the first storage battery 116, the voltage V2 = 310V of the second storage battery 110, the current I = 10A flowing through the second storage battery 110, and the efficiency X = 0.95 of the conversion circuit 122. Assuming, from the definition of η and the number 5, η = (1-0.95) /0.95=0.0526
E = 1 / (1 + 0.0526 × (1-300 / 310))
≒ 0.9983
And the loss is 1% or less. In the case of the conventional connection method shown in FIG. 13, the first storage battery 116 and the second storage battery 110 are connected via the conversion circuit 122. In this case, the efficiency is 0.95, which is the efficiency of the conversion circuit 122. It can be seen that the efficiency can be significantly improved by using the conversion device 120 of the present embodiment as compared with the conventional case in which a loss of about 5% has occurred. It can be seen that the efficiency is significantly improved by the same calculation in configurations 2 to 4. Further, from Equation 5, it can be seen that the closer the voltage V1 of the first storage battery 116 and the voltage V2 of the second storage battery 110 are, the closer E approaches 1 (the efficiency increases). It can be seen that this method is particularly effective when the potential difference between the original storage battery that transfers electric power and the storage battery at the destination is small and the respective voltages are high.

Further, the required capacity of the conversion circuit 122 can also be reduced according to the conversion device 120 of the present embodiment. That is, in the above assumed numerical value, the output voltage V4 of the conversion circuit 122 is V4 = V2-V1 = 10 [V] and the current I = 10 [A]. Therefore, the output power P4 of the conversion circuit 122 is P4. = V4 × I = 100 [W]. On the other hand, if it is a conventional conversion device, it is necessary to convert the input power P2 = V2 × I = 3100 [W] to the second storage battery 110, so it is necessary to use a component with a withstand voltage corresponding to the conversion, and the product. There is a problem that the cost becomes high. On the other hand, in the conversion device 120 of the present embodiment, the capacity of the conversion circuit 122 can be reduced and the cost of the parts used can be kept low, so that the product cost can be reduced.

As described above, according to the conversion device 120 of the present embodiment, it is possible to transfer power between two storage batteries (first storage battery 116, second storage battery 110) having different voltages extremely efficiently, and the product cost. Can be kept low. Further, in the power supply system 102 of the present embodiment, the surplus power can be charged to the first storage battery 116 and the insufficient power can be replenished from the first storage battery 116, and if the second storage battery 110 is installed, the first storage battery 116 can be used. Electric power can be transferred to and from the second storage battery 110, and the second storage battery 110 can function as an external rechargeable battery.

In the above-described embodiment, the case where the first storage battery 116 and the second storage battery 110 are already connected to the conversion device 120 has been described, but the first storage battery 116 or the second storage battery 110 is newly added to the conversion device 120. When trying to connect, if there is a voltage difference between the storage battery to be connected and the terminal pair, an inrush current is generated at the time of connection, which is not preferable. As a countermeasure in such a case, the conversion device 120 suppresses the inrush current between the first terminal pair 124 and the first storage battery 116, or between the second terminal pair 126 and the second storage battery 110. An inrush current suppressing means can be provided.

FIG. 4 is a block diagram showing a conversion device 140 which is a modification of the conversion device 120, and shows an example when a switch is used as the above-mentioned inrush current suppressing means. The conversion device 140 shown in FIG. 4 is an example in which the switch SW2 is arranged between the second terminal pair 126 of the conversion device 120 and the second storage battery 110. In this case, the second terminal pair 126 is the "connected terminal pair to be connected", and the second storage battery 110 is the "connected storage battery to be connected". When the second storage battery 110 is to be connected to the second terminal pair 126, the conversion circuit 122 uses the terminal voltage of the second terminal pair 126 (connected terminal pair) as the output voltage of the second storage battery 110 (connected storage battery). After that, the switch mechanism SW2 is turned on. By providing the switch SW2 and controlling the conversion circuit 122 as described above, the second storage battery 110 can be safely connected without generating an inrush current. Similarly, when the first storage battery 116 is to be connected to the first terminal pair 124, a switch can be provided between the first terminal pair 124 and the first storage battery 116.

FIG. 5 is a block diagram showing a conversion device 142 which is another modification of the conversion device 120, and shows an example when a feedback circuit is used as the above-mentioned inrush current suppressing means. The conversion device 142 shown in FIG. 5 is a feedback circuit 144b that feedback-controls the ammeter 144a for measuring the current flowing through the second storage battery 110, which is a connected storage battery, and the conversion circuit 122 so that the measured value of the ammeter 144a gradually increases or decreases. And have. By configuring the feedback circuit 144b, the second storage battery 110 can be safely connected without generating an inrush current. Even when the first storage battery 116 is to be connected to the first terminal pair 124, a similar feedback circuit can be configured on the side of the first terminal pair 124 to prevent an inrush current to the first storage battery 116.

FIG. 6 is a block diagram showing a conversion device 146 which is still another modification of the conversion device 120, and shows an example when the DC power conversion device 148 is used as the above-mentioned inrush current suppressing means. The DC power conversion device 148 shown in FIG. 6 is a device that converts DC power in the same manner as the conversion device 120, and is provided between the second terminal pair 126 and the second storage battery 110. Further, the DC power conversion device 148 is controlled so that the series connection voltage between the conversion circuit 122 of the DC power conversion device 148 and the connected storage battery matches the voltage between the terminals of the connected terminal pair. The control and operation of the DC power converter 148 are the same as those of the converter 120. By providing the DC power conversion device 148, the second storage battery 110 can be safely connected without generating an inrush current. When the first storage battery 116 is to be connected to the first terminal pair 124 in the conversion device 120, a DC power conversion device can be similarly provided between the first terminal pair 124 and the first storage battery 116. ..

The DC power conversion device 148 and the second storage battery 110 shown in FIG. 6 can also be grasped as the power storage module 150. FIG. 7 is a block diagram showing details of the power storage module 150. The power storage module 150 includes a storage battery 152 and a conversion circuit 154. The conversion circuit 154 is the same as the conversion circuit 122. The power from the storage battery 152 is input to the input of the conversion circuit 154, and the output of the conversion circuit 154 is connected in series with the storage battery 152. That is, the power storage module 150 is a single or a plurality of storage batteries (first storage battery 116 or second storage battery 110) connected to the above-mentioned conversion device 120 and the first terminal pair 124 or the second terminal pair 126 of the conversion device 120. ), And can be said to be equivalent to those having.

(Embodiment 2)
In the first embodiment, the case where the first storage battery 116 and the second storage battery 110 are each single has been described, but one or both of the first storage battery 116 and the second storage battery 110 may be plural. That is, the first terminal pair 124 or the second terminal pair 126 may connect a plurality of storage batteries connected in parallel to each other. When trying to connect a plurality of storage batteries in parallel to each other, if there is a voltage difference between the two storage batteries, an inrush current is generated at the time of connection, which is not preferable. As a countermeasure in such a case, an inrush current suppressing means for suppressing the inrush current can be provided corresponding to each of the plurality of storage batteries.

FIG. 8 is a block diagram showing an example in which a plurality of storage batteries are connected in parallel to the second terminal pair 126, and shows an example in the case where a switch is used as the above-mentioned inrush current suppressing means. A switch mechanism between the connected terminal pair to be added (second terminal pair 126) and the connected storage battery (second storage battery 110-2, third storage battery 110-3, nth storage battery 110-n) to be added. (SW2, SW3, SWn) are arranged. In this case, the terminal voltage of the terminal pair (connected terminal pair) of the already connected storage battery is controlled by the conversion circuit 122 so as to match the output voltage of the connected storage battery to be connected, and then the switch mechanism (SW2) is used. , SW3, SWn), the switch mechanism connected to the storage battery with the same voltage is turned on. This can prevent inrush current due to parallel connection.

When one or more of the switch mechanisms are already ON and another storage battery is connected, a part of the power stored in the already connected connected storage battery is moved to the first storage battery 116, or the first storage battery 116 is connected. By moving a part of the electric power stored in the storage battery 116 to the connected storage battery that is already connected, the voltage of the second terminal to 126 can be adjusted, and the voltage with the storage battery to be connected matches. Sometimes, the switch mechanism connected to the storage battery to be connected can be turned on.

FIG. 9 is a block diagram showing an example in which a plurality of storage batteries are connected in parallel to the second terminal pair 126, and shows an example in the case where a DC power conversion device is used as the above-mentioned inrush current suppressing means. For each of the plurality of storage batteries (second storage battery 110-2, third storage battery 110-3, nth storage battery 110-n) connected in parallel with each other, the same DC power conversion device 160-2, 160-3 as the conversion device 120 , 160-n are arranged. The DC power converters 160-2, 160-3, 160-n receive power from the connected storage battery to be connected, and the series connection voltage with the connected storage battery is the terminal of the connected terminal pair to which the connected storage battery is already connected. It is controlled to match the inter-voltage. This can prevent inrush current due to parallel connection. In this example, the conversion circuit 122 can be omitted, and in this case, the first terminal pair 124 and the second terminal pair 126 are directly connected.

By providing the inrush current suppressing means shown in FIGS. 8 and 9, a plurality of storage batteries are connected in parallel, and the plurality of storage batteries connected in parallel can be connected to the second terminal pair 126. As a result, the capacity of the storage battery connected to the second terminal pair 126 can be appropriately increased or decreased. It should be noted that a plurality of storage batteries connected in parallel can be connected to the first terminal pair 124, and in this case, the inrush current suppressing means described above is provided for each of the plurality of storage batteries connected to the first terminal pair 124. Can be provided.

(Embodiment 3)
FIG. 10 is a block diagram showing a modified example of the conversion device 120. In the example shown in FIG. 10, in addition to the configuration of the conversion device 120 described above, the electric energy meter 170 and the control device 172 are provided. The watt-hour meter 170 measures the amount of power output from the second terminal pair 126, and the control device 172 reduces the amount of power output when the measured value of the watt-hour meter 170 reaches a predetermined value to zero. The conversion circuit 122 is controlled so as to be. Thereby, the amount of electric power supplied to the second storage battery 110 can be controlled. For example, when the DC power generated by the power generation / distribution system 100 is sold, the sold power can be stored in the second storage battery 110 and sold. In such a case, the control device 172 may output the billing information 174 according to the output electric energy. The same configuration may be provided on the side of the first terminal pair 124.

The billing information 174 may be calculated by determining the unit price of the unit electric energy and multiplying the electric energy obtained by the electricity meter 170 by the unit price. Further, regarding the amount of power output from the first terminal pair 124 or the second terminal pair 126, it is decided to move a fixed amount of power at regular time intervals, and billing information is calculated from the moved time. May be good.

(Embodiment 4)
In the first embodiment, an example in which the power supply system 102 has the first storage battery 116 has been described, but in the present embodiment, an example in which the power supply system does not include the storage battery will be described. FIG. 11 is a block diagram showing an example of the power generation / distribution system 200. The power generation / distribution system 200 has a power supply system 202, and the power supply system 202 receives power from a DC power source 104 or an AC power 106 and distributes DC power to a DC load 108. Further, the power supply system 202 supplies DC power to the second storage battery 110 and receives DC power from the second storage battery 110. The AC power 106 is not an essential configuration requirement for the power generation / distribution system 200.

The power supply system 202 includes a DC distribution device 112, an AC / DC conversion device 114, and a conversion device 220. The DC power distribution device 112 and the AC / DC conversion device 114 are the same as those described in the first embodiment.

FIG. 12 is a block diagram showing details of the conversion device 220. The conversion device 220 is a power conversion device for transferring the DC power from the DC distribution device 112 to a single or a plurality of storage batteries, in this example, the second storage battery 110. The conversion device 220 has a conversion circuit 122, a first terminal pair 124, and a second terminal pair 126 similar to those described in the first embodiment. The first terminal pair 124 is connected to the DC power distribution device 112, and the second terminal pair 126 is connected to the second storage battery 110. The second storage battery 110 is an example of a single or a plurality of storage batteries.

Similar to the first embodiment, the conversion circuit 122 has a third terminal pair 128 and a fourth terminal pair 130, and receives DC power input to one terminal pair of the third terminal pair 128 and the fourth terminal pair 130. DC output is performed by controlling the voltage or current to the other terminal pair. The third terminal pair 128 of the conversion circuit 122 in the present embodiment is connected in parallel with the second terminal pair 126, unlike the case of the first embodiment. As a result, the conversion circuit 122 input can always receive power from the second storage battery 110. The point that the first terminal pair 124 and the fourth terminal pair 130 are connected in series and the first terminal pair 124 and the fourth terminal pair 130 and the second terminal pair 126 connected in series are connected in parallel is an embodiment. It is the same as 1.

By configuring the conversion device 220 as described above, even in the power supply system 202 that does not have a storage battery, the conversion circuit 122 can be normally operated when the external storage battery (second storage battery 110) is connected. .. By not including the storage battery in the power supply system 202, the cost of the power supply system 202 is reduced, and an external storage battery (second storage battery 110) is installed as needed to move the surplus power to the external storage battery, resulting in insufficient power. Can be supplemented by receiving power from an external storage battery. Further, by providing the configuration of the second embodiment, the number of external storage batteries can be increased or decreased, and by providing the configuration of the third embodiment, the generated power can be sold.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

For example, the external storage battery exemplified for the second storage battery 110 can be an in-vehicle storage battery, and the power transfer with the external storage battery can be used not only for selling power but also for buying power.

100 ... power generation and distribution system, 102 ... power supply system, 104 ... DC power supply, 106 ... AC power, 108 ... DC load, 110 ... second storage battery, 112 ... DC power distribution device, 114 ... AC / DC converter, 116 ... first Storage battery, 120 ... Conversion device, 122 ... Conversion circuit, 124 ... 1st terminal pair, 126 ... 2nd terminal pair, 128 ... 3rd terminal pair, 130 ... 4th terminal pair, 140 ... Conversion device, SW2 ... Switch mechanism, 142 ... Conversion device, 144a ... Current meter, 144b ... Feedback circuit, 146 ... Conversion device, 148 ... DC power conversion device, 150 ... Power storage module, 152 ... Storage battery, 154 ... Conversion circuit, SW3, SWn ... Switch mechanism, 110- 2 ... 2nd storage battery, 110-3 ... 3rd storage battery, 110-n ... nth storage battery, 160-2, 160-3, 160-n ... DC power converter, 170 ... power meter, 172 ... control device, 174 ... Billing information, 200 ... Power generation and distribution system, 202 ... Power supply system, 220 ... Conversion device.

Claims (11)

A converter for transferring power between multiple storage batteries.
A first terminal pair connected to one of the plurality of storage batteries,
A second terminal pair connected to another storage battery among the plurality of storage batteries,
It has a third terminal pair and a fourth terminal pair, and outputs DC power input to one terminal pair of the third terminal pair and the fourth terminal pair by controlling the voltage or current to the other terminal pair. With an isolated conversion circuit,
The first terminal pair and the third terminal pair are connected in parallel,
The first terminal pair and the fourth terminal pair are connected in series, and the first terminal pair is connected in series.
A conversion device in which the first terminal pair, the fourth terminal pair, and the second terminal pair connected in series are connected in parallel. The terminal voltage V1 of the first terminal pair is lower than the terminal voltage V2 of the second terminal pair (V1 <V2), and the storage battery connected to the first terminal pair is connected to the second terminal pair. In the conversion circuit, one end of the fourth terminal pair connected to the negative electrode side of the first terminal pair is a positive electrode, the other end is a negative electrode, and the third terminal pair is an input terminal. , The first configuration, which causes the fourth terminal pair to function as an output terminal.
The terminal voltage V1 of the first terminal pair is higher than the terminal voltage V2 of the second terminal pair (V1> V2), and the storage battery connected to the first terminal pair is connected to the second terminal pair. In the conversion circuit, one end of the fourth terminal pair connected to the negative electrode side of the first terminal pair is a negative electrode, the other end is a positive electrode, and the third terminal pair is an output terminal. , A second configuration in which the fourth terminal pair functions as an input terminal,
The terminal voltage V1 of the first terminal pair is higher than the terminal voltage V2 of the second terminal pair (V1> V2), and the storage battery connected to the second terminal pair is connected to the first terminal pair. In the conversion circuit, one end of the fourth terminal pair connected to the negative electrode side of the first terminal pair is a negative electrode, the other end is a positive electrode, and the third terminal pair is an input terminal. , A third configuration, or a third configuration in which the fourth terminal pair functions as an output terminal.
The terminal voltage V1 of the first terminal pair is lower than the terminal voltage V2 of the second terminal pair (V1 <V2), and the storage battery connected to the second terminal pair is connected to the first terminal pair. In the conversion circuit, one end of the fourth terminal pair connected to the negative electrode side of the first terminal pair is a positive electrode, the other end is a negative electrode, and the third terminal pair is an output terminal. , A fourth configuration in which the fourth terminal pair functions as an input terminal,
The conversion device according to claim 1, which has any of the above configurations. Further having an inrush current suppressing means for suppressing an inrush current that may occur when the storage battery is connected to the first terminal pair or the second terminal pair.
The inrush current suppressing means is a switch mechanism arranged between the connected terminal pair to be connected and the connected storage battery to be connected, and the terminal voltage of the connected terminal pair is connected in the conversion circuit. The first configuration, in which the switch mechanism is turned on after being controlled to match the output voltage of the storage battery,
A second configuration in which the inrush current suppressing means includes an ammeter that measures the current flowing through the connected storage battery, and a feedback circuit that feedback-controls the conversion circuit so that the measured value of the ammeter gradually increases or decreases. ,or,
The inrush current suppressing means is a DC power conversion device similar to the conversion device, and the DC power is such that the series connection voltage between the DC power conversion device and the connected storage battery matches the terminal voltage of the connected terminal pair. A third configuration that controls the converter,
The conversion device according to claim 1 or 2, which has any of the above configurations. The conversion device according to any one of claims 1 to 3, wherein the first terminal pair or the second terminal pair connects a plurality of storage batteries connected in parallel to each other. Further, it has an inrush current suppressing means for suppressing an inrush current that may occur when one of the plurality of storage batteries is added corresponding to each of the plurality of storage batteries.
The inrush current suppressing means is a switch mechanism arranged between the connected terminal pair to be added and the connected storage battery to be added, and the terminal voltage of the connected terminal pair is connected in the conversion circuit. After controlling to match the output voltage of the storage battery, the switch mechanism is turned on, the first configuration, or
The inrush current suppressing means is a DC power conversion device similar to the conversion device, and the DC power is such that the series connection voltage between the DC power conversion device and the connected storage battery matches the terminal voltage of the connected terminal pair. A second configuration that controls the converter,
The conversion device according to claim 4, which has any of the above configurations. A watt-hour meter that measures the amount of power output from the first terminal pair or the second terminal pair,
Any one of claims 1 to 5, further comprising a control device that controls the conversion circuit so that the amount of power output when the measured value of the watt-hour meter reaches a predetermined value becomes zero. The converter described in the section. The conversion device according to claim 6, wherein the control device outputs billing information according to the amount of output power. The conversion device according to any one of claims 1 to 7.
A power storage module having a single or a plurality of storage batteries connected to the first terminal pair or the second terminal pair. A DC power distribution device that supplies DC power from a DC power supply to a DC load,
The power storage module according to claim 8 is provided.
A power supply system that stores surplus power in the power storage module and supplies insufficient power from the power storage module. A DC power distribution device that supplies DC power from a DC power supply to a DC load,
It has a conversion device for transferring DC power from the DC distribution device to a single or a plurality of storage batteries, and has.
The conversion device
A first terminal pair that receives DC power from the DC distribution device,
A second terminal pair connected to the single or multiple storage batteries,
It has a third terminal pair and a fourth terminal pair, and outputs DC power input to one terminal pair of the third terminal pair and the fourth terminal pair by controlling the voltage or current to the other terminal pair. With an isolated conversion circuit,
The second terminal pair and the third terminal pair are connected in parallel, and the second terminal pair is connected in parallel.
The first terminal pair and the fourth terminal pair are connected in series, and the first terminal pair is connected in series.
A power supply system in which the first terminal pair, the fourth terminal pair, and the second terminal pair connected in series are connected in parallel. It also has an AC-DC converter that receives commercial AC power and converts the received AC power into DC power.
The power supply system according to claim 9 or 10, wherein the DC distribution device distributes DC power from the AC / DC conversion device in addition to DC power from the DC power source.

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