JP6924068B2 - Parallel connection storage battery system and its control device - Google Patents

Description

The present invention relates to a parallel connection storage battery system and a control technique thereof.

Error comparing the output voltage with the reference signal of the sine wave In the parallel operation of the inverters in which the output of the amplification circuit is controlled by connecting multiple inverters in parallel via the PWM drive circuit, the output current of the inverters is detected. When a means for adding or subtracting a signal to or subtracts from the input or output of the error amplification circuit is provided so as to lower the output voltage of the inverter, the output current detection signal is added to the signal from the sinusoidal generation circuit. , When giving to the error amplification circuit together with the output voltage detection signal and raising the output voltage of the inverter, add the current detection signal and the voltage detection signal, give the signal from the sinusoidal wave generation circuit to the error amplification circuit, and between the inverters. There is known an inverter parallel operation method characterized by controlling the cross current in the above (see Patent Document 1).

Special Fair 6-40704 Gazette

In the technique described in Patent Document 1, the output of an inverter is connected to a parallel bus, other inverters are also connected to the parallel bus, and a plurality of inverters are operated in parallel to supply AC power to a load. Further, the output power and the output current are detected, and the inverter is controlled through the error amplification circuit and the PWM drive circuit together with the reference sine wave generation circuit.

However, when parallel operation is controlled based on the information of the inverter output, there is a slight deviation in the voltage signal for operating each inverter. Due to this deviation, a slight deviation also occurs in the discharge power of each storage battery.

In particular, in the discharge operation of the storage battery, a slight deviation of the output voltage signal of the inverter is accumulated, resulting in a large deviation of the discharge power amount of the storage battery. Then, the voltage of the storage battery having a large amount of discharge power drops early, and the inverter stops when the voltage becomes lower than the input voltage used by the inverter.

As described above, when the conventional control is used, there is a problem that the operable time of the load by the storage battery is shortened due to a slight deviation of the output power of the inverter.
An object of the present invention is to increase the operable time in parallel operation of storage batteries.

According to one aspect of the present invention, it is a plurality of power conversion devices having a plurality of DC / DC converters and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and the AC outputs of the DC / DC converters are parallel to each other. It has a plurality of power conversion devices for connecting and supplying power to a load, and a plurality of storage batteries connected to each of the plurality of the power conversion devices, and at least one of the output voltage and the remaining capacity of the storage battery. Provided is a parallel connection storage battery system characterized by having a control circuit for controlling an output voltage of an inverter connected to the storage battery based on electrical information.

It is preferable that the control circuit controls to change the output voltage of the inverter connected to the storage battery in a direction in which the output voltages of the plurality of storage batteries become equal to each other, based on the output voltage of the storage battery.
The control circuit may control the output voltage of the inverter connected to the storage battery to be changed in a direction in which the remaining capacities of the plurality of storage batteries are equal to each other, based on the remaining capacity of the storage battery.
The control circuit changes the output voltage of the inverter connected to the storage battery in a direction in which the output voltages of the plurality of storage batteries become equal, based on the difference between the output voltage of the storage battery and the average value of all the storage battery voltages. It is good to control.
The control circuit sets the output voltage of the inverter connected to the storage battery in a direction in which the remaining capacities of the plurality of storage batteries become equal to each other, based on the difference between the remaining capacity of the storage batteries and the average value of the remaining capacities of all the storage batteries. The control to change may be performed.
The control circuit includes a storage battery information processing circuit and an inverter voltage control circuit, and the storage battery information processing circuit outputs an inverter output voltage command value to the inverter voltage control circuit based on the electrical characteristics of the storage battery. The inverter voltage control circuit may control the inverter voltage based on the inverter output voltage command value from the storage battery information processing circuit.

Further, it may be connected to the node between the DC / DC converter and the inverter, and may have a series connection circuit of the renewable energy generator and the converter.
Further, it may be connected to the node between the DC / DC converter and the inverter to have a series connection circuit of the commercial power supply and the AC / DC converter.

Further, the present invention is a plurality of power conversion devices having a plurality of DC / DC converters and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and each AC output is connected in parallel to load. A control device for a parallel connection storage battery system having a plurality of power conversion devices for supplying power to the power conversion device and a plurality of storage batteries connected to each of the plurality of power conversion devices, and the output voltage or remaining capacity of the storage batteries. It is a control device of a parallel connection storage battery system that controls the output voltage of the inverter connected to the storage battery based on the electrical information of at least one of the above.

According to the present invention, the operable time in the parallel operation of the storage batteries can be lengthened.

It is a functional block diagram which shows one configuration example of the parallel connection storage battery system which used the parallel connection storage battery control technique by 1st Embodiment of this invention. It is a functional block diagram which shows one configuration example of the inverter control circuit which controls the inverter device by this embodiment. It is a functional block diagram which shows one configuration example of the inverter control circuit which controls the inverter device by this embodiment. It is a functional block diagram which shows one structural example of the inverter control circuit which controls the inverter device by 2nd Embodiment of this invention. It is a functional block diagram which shows one structural example of the inverter control circuit which controls the inverter device by 2nd Embodiment of this invention. It is a functional block diagram which shows one structural example of the inverter voltage control circuit common to 1st Embodiment and 2nd Embodiment. It is a functional block diagram which shows one configuration example of the parallel connection storage battery system using the parallel connection storage battery control technique according to the 3rd Embodiment of this invention. It is a functional block diagram which shows one configuration example of the parallel connection storage battery system which used the parallel connection storage battery control technique by 4th Embodiment of this invention.

Hereinafter, the parallel connection storage battery control technique according to the embodiment of the present invention will be described in detail with reference to the drawings.

(First Embodiment)
FIG. 1 is a functional block diagram showing a configuration example of a parallel connection storage battery system using the parallel connection storage battery control technology according to the embodiment of the present invention.
As shown in FIG. 1, the parallel connection storage battery system 1 includes DC / DC converters 13, ..., 23 and inverters 15, ..., 25 that convert the output voltages of the DC / DC converters 13, ..., 23 into AC voltage. It has a plurality of power conversion devices 16, ..., 26 having a plurality of. The power conversion devices 16, ..., 26 connect their AC outputs in parallel and supply power to the load 31. A plurality of storage batteries 11, ..., 21 are provided as power supply sources on the input sides of the plurality of power converters 16, ..., 26. The inverter devices 10, ..., 20 are power conversion devices 16, ..., 26 that are connected to the storage batteries 11, ..., 21, respectively.

Further, the parallel connection storage battery system 1 has control circuits 51, ..., 61 in the power conversion devices 16, ..., 26. The control circuits 51, ..., 61 are based on their own electrical information of at least one of the output voltage and the remaining capacity (SOC) of the storage batteries 11, ..., 21 for each of the power converters 16, ..., 26. , Control / adjust the output voltage of the inverter connected to its own storage battery. The control circuit 51 includes, for example, storage battery information processing circuits 53, ..., 63, and inverter voltage control circuits 55, ..., 65. The storage battery information processing circuits 53, ..., 63 have inverter output voltage command values (S2) in the storage battery information processing circuits 53, ..., 63 based on the electrical characteristics (S1, ..., S11) of the storage batteries 11, ..., 21. , ..., S21) is output. The inverter voltage control circuits 55, ..., 65 control signals (S3, ..., S31) based on the inverter output voltage command values (S2, ..., S21) from the storage battery information processing circuits 53, ..., 63. ) Is output. The storage battery information processing circuits 53, ..., 63 and the inverter voltage control circuits 55, ..., 65 may be integrated.

FIG. 2A is a functional block diagram showing a configuration example of a storage battery information processing circuit 53 (, ..., 63) (see FIG. 1) that controls the inverter devices 10, ..., 20 according to the present embodiment. Here, the storage battery information processing circuit 53 will be described. As shown in FIG. 2A, the storage battery information processing circuit 53 has, for example, a circuit configuration in which the subtractor 161 and the proportional control unit 163 and the adder 165 are connected in series.

Let V1 be the storage battery voltage that can be used as its own electrical information. The reference value Vs is, for example, the center voltage in the operating range of the storage battery 11. The subtractor 161 subtracts the reference value Vs of the storage battery voltage from the storage battery voltage V1 to obtain the differential voltage (V1-Vs). The proportional control unit 163 amplifies or attenuates the differential voltage.

The inverter output voltage reference value Vinvs is a reference value of the effective output voltage value of the inverter 15. The adder 165 adds the output of the proportional control unit 163 and the inverter output voltage reference value Vinvs. Then, when the storage battery voltage V1 is higher than the reference value Vs, the inverter output voltage command value Vinv1 becomes large, and when the storage battery voltage V1 is lower than the reference value Vs, the inverter output voltage command value Vinv1 is corrected to be small. The inverter output voltage command value Vinv1 corrected in this way is output to the inverter voltage control circuit 55.
The inverter voltage control circuit 55 controls the gate voltage of the inverter 15 based on the inverter output voltage command value Vinv1.
Therefore, the control circuit 51 controls the input of the inverter 15 based on the storage battery voltage V1, and as a result, controls the output voltage of the inverter 15 to the load 31.

In the parallel connection storage battery system 1 shown in FIGS. 1 and 2A, the control circuits 51, ..., 61 monitor the voltages of the storage batteries 11, ..., 21 and the inverters 15, ... Based on the voltages of the storage batteries 11, ..., 21. , 25 output voltage is changed. Then, the control circuits 51, ..., 61 control so that the voltages of the respective storage batteries 11, ..., 25, 21 change in the same direction. The control contents will be described in detail below.

When the voltage of its own storage battery is high, the output voltage of the inverter is changed in the high direction. Then, the load sharing amount of the own inverter increases. Therefore, the discharge power from the storage battery increases, and the voltage of the own storage battery drops faster. As a result, the voltage of each storage battery becomes equal.
On the other hand, when the voltage of the own storage battery is low, the output voltage of the inverter is changed in the low direction. Then, the load sharing amount of the own inverter becomes small. Therefore, the discharge power from the storage battery is reduced, and the voltage drop of the own storage battery is delayed. As a result, the voltage of each storage battery becomes equal.

In the above example, the storage battery voltage V1 is used as the self-electrical information, but as shown in FIG. 2B, the battery capacity SOCs of the storage batteries 11, ..., 21 are used as the self-electrical information. State Of Charge), for example, the current remaining capacity may be a percentage when the full charge is 100%.
As the storage battery SOC reference value, the central SOC in the operating range of the storage battery or the like can be used.

The proportional control unit 163 amplifies or attenuates the difference between the storage battery calculation capacity SOC1 and the storage battery calculation capacity reference value SOCs.

As described above, according to the present embodiment, there is an advantage that the shortening of the operable time of the load by the storage battery is suppressed due to the slight deviation of the output power of the inverter.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 3A is a functional block diagram showing a configuration example of a storage battery information processing circuit 53 (, ..., 63) that controls the inverter devices 10, ..., 20 according to the first embodiment, and is a storage battery information shown in FIG. 2B. It is a figure corresponding to the processing circuit 53. As shown in FIG. 3A, the storage battery information processing circuit 53 according to the present embodiment includes a subtractor 161, a proportional control unit 163, and an adder 165. However, instead of the reference value Vs of the storage battery voltage of FIG. 2A, as shown in FIG. 3A, an average value calculation unit 67 for obtaining statistical values, for example, average values of the storage batteries 11, ..., 21 is provided.

The storage battery voltage of the storage batteries 11, ..., 21 is the storage battery voltage of each device transmitted from each device by communication or the like. The average value calculation unit 67 calculates the average value of the storage battery voltage of each storage battery. Alternatively, the master device may calculate the average voltage and pass it to each device.

Note that FIG. 4 is a functional block diagram showing a configuration example of the inverter voltage control circuits 55, ..., 65 common to the first embodiment and the second embodiment. Here, the inverter voltage control circuit 55 will be described.
The inverter voltage control circuit 55 subtracts a value obtained by applying the effective value circuit 83 to the output of the inverter output voltage detector 81 from the inverter output voltage command value Vinv by the subtractor 85.

Then, the output of the subtractor 85 is PI-controlled by the PI control unit 87 and output to the multiplier 91. The multiplier 91 multiplies the output of the PI control unit 87 with the reference sine wave Ws. The subtractor 93 subtracts the output of the multiplier 91 from the inverter output voltage detector 81, and the output is amplified by the amplifier 95.

The output of the amplifier 95 is subtracted from the output of the inverter output current detector 99 by the subtractor 97 and output to the PWM signal generation circuit 101. The output of the PWM signal generation circuit 101 becomes the gate signal of the inverter.

As described above, the inverter output voltage detection detected by the voltage detector (not shown) is converted into the effective value by the effective value circuit 83. The difference voltage between the signal converted to the effective value and the inverter output voltage command value sent from the control circuit is calculated. The differential voltage signal is amplified by PI control and controlled in the direction in which the differential voltage signal becomes zero.

That is, the reference sine wave, which is controlled so that the effective value of the output voltage of the inverter is equal to the inverter output voltage command value, is not described here, but is transmitted by a circuit that matches the phase with the output frequency of the inverter of each device. This is the reference sine wave of the inverter to be used.

The differential voltage signal amplified by PI control is multiplied by the reference sine wave and becomes the AC inverter output voltage reference. The difference between the AC inverter output voltage reference and the inverter output voltage detection is calculated, amplified by an amplifier, and controlled so that the difference signal becomes zero.

The inverter output current detection is subtracted from the output signal of the amplifier, and the gate signal of the inverter is generated by the PWM signal generation circuit. As a result, the AC waveform of the inverter output voltage is controlled to be the AC inverter output voltage reference value.

Subtracting the signal for detecting the inverter output current from the output of the amplifier is, for example, a technique shown in Japanese Patent Publication No. 6-40704, and can control the cross flow between the inverters.

In the above example, an example in which the storage battery voltage is used as its own electrical information is shown, but as shown in FIG. 3B, as its own electrical information, the storage batteries 11, ..., 21 The battery capacity SOC (State Of Charge) of the above, for example, the percentage of the current remaining capacity when the full charge is 100% may be used.

(Third Embodiment)
FIG. 5 is a functional block diagram showing a configuration example of a parallel connection storage battery system using the parallel connection storage battery control technology according to the third embodiment of the present invention.
Unlike the circuit configuration shown in FIG. 1, in the circuit configuration 201 shown in FIG. 5, the solar cells 210, ..., 220 and the converters 213, ..., 223 are connected in series on the input side of the inverters 15, ..., 25. It differs in that it does. Other configurations are the same as in FIG. The power conversion device is indicated by the reference numerals 16a and 26a.

The solar cell may use renewable electric power such as a rechargeable battery based on geothermal power generation, which can be regenerated by other natural energy.
In a system equipped with a solar cell, the storage battery is charged by power generation from the solar cell. Therefore, the operation time of the inverter considering the charging from the solar cell is assumed. Since the operating time of this parallel connection storage battery system is longer than in other examples, the accumulation of the difference in discharge power becomes larger, and the ratio of the operating time shortening compared to the assumed operating time becomes large.
Therefore, in the system as shown in FIG. 5, there is an advantage that the control according to the present embodiment is more effective.

(Fourth Embodiment)
FIG. 6 is a functional block diagram showing a configuration example of a parallel connection storage battery system using the parallel connection storage battery control technology according to the fourth embodiment of the present invention.
Compared with the configuration shown in FIG. 1, in the configuration shown in FIG. 6, the commercial power supply (AC power supply) 310, ..., 320 and the converters 213, ..., 223 are connected in series on the input side of the inverters 15, ..., 25. It differs in that it has. Other configurations are the same as in FIG. The power converter is indicated by the reference numerals 16b, ... 26b.
The system shown in FIG. 6 has an advantage that it can be operated by a storage battery when a commercial power source becomes unavailable during a power failure.

In the above embodiment, the configuration and the like shown in the accompanying drawings are not limited to these, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the scope of the object of the present invention. For example, it goes without saying that different circuits having similar functions may be used for the components of the circuit.
In addition, each component of the present invention can be arbitrarily selected, and an invention having the selected configuration is also included in the present invention.

The present invention can be used in a parallel connection storage battery system and a control device thereof.

1 ... Parallel connection storage battery system, 10 ... Inverter device, 11 ... Storage battery, 13 ... DC / DC converter, 15 ... Inverter, 16 ... Power converter, 31 ... Load, 51 ... Control circuit, 53 ... Storage battery information processing circuit, 55 … Inverter voltage control circuit.

Claims (6)

A plurality of power conversion devices including a DC / DC converter and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and a plurality of power conversion devices that connect the AC outputs in parallel to supply power to a load. It has a power converter and a plurality of storage batteries connected to the input side of each of the DC / DC converters of the power converter.
It has a control circuit that controls the output voltage of the inverter connected to the storage battery based on the output voltage of the storage battery.
The control circuit
When the voltage of the storage battery is high, the output voltage of the inverter is changed in a high direction based on the difference between the output voltage of the storage battery and the average value of all the storage battery voltages, and when the voltage of the storage battery is low. A parallel connection storage battery system that controls the output voltage of the inverter connected to the storage battery so as to change the output voltage of the inverter in a low direction. A plurality of power conversion devices including a DC / DC converter and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and a plurality of power conversion devices that connect the AC outputs in parallel to supply power to a load. It has a power converter and a plurality of storage batteries connected to the input side of each of the DC / DC converters of the power converter.
It has a control circuit that controls the output voltage of the inverter connected to the storage battery based on the remaining capacity of the storage battery.
The control circuit
A remaining capacity of the battery, based on the difference between the average value of the remaining capacity of all of the storage battery, wherein when the remaining capacity of the storage battery is not much, to change the output voltage of the inverter to a higher direction, of said battery If the remaining capacity is not small, parallel-connected battery system for controlling the output voltage of the inverter connected to the battery so as to change the output voltage of the inverter to a lower direction. The parallel connection storage battery system according to claim 1 or 2, further comprising a series connection circuit of a renewable energy generator and a converter connected to a node between the DC / DC converter and the inverter. The parallel connection storage battery system according to claim 1 or 2, further comprising a series connection circuit of a commercial power supply and an AC / DC converter connected to a node between the DC / DC converter and the inverter. A plurality of power conversion devices including a DC / DC converter and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and a plurality of power conversion devices that connect the AC outputs in parallel to supply power to a load. A control device for a parallel connection storage battery system having a power conversion device and a plurality of storage batteries connected to the input side of the DC / DC converter of the power conversion device.
It has a control circuit that controls the output voltage of the inverter connected to the storage battery based on the output voltage of the storage battery.
The control circuit
When the voltage of the storage battery is high, the output voltage of the inverter is changed in a high direction based on the difference between the output voltage of the storage battery and the average value of all the storage battery voltages, and when the voltage of the storage battery is low. A control device for a parallel connection storage battery system that controls the output voltage of the inverter connected to the storage battery so as to change the output voltage of the inverter in a low direction. A plurality of power conversion devices including a DC / DC converter and an inverter that converts the output voltage of the DC / DC converter into an AC voltage, and a plurality of power conversion devices that connect the AC outputs in parallel to supply power to a load. A control device for a parallel connection storage battery system having a power conversion device and a plurality of storage batteries connected to the input side of the DC / DC converter of the power conversion device.
It has a control circuit that controls the output voltage of the inverter connected to the storage battery based on the remaining capacity of the storage battery.
The control circuit
Based on the difference between the remaining capacity of the storage battery and the average value of the remaining capacity of all the storage batteries, when the remaining capacity of the storage battery is large, the output voltage of the inverter is changed in a high direction to obtain the remaining capacity of the storage battery. When the amount is small, a control device for a parallel connection storage battery system that controls the output voltage of the inverter connected to the storage battery so as to change the output voltage of the inverter in a low direction.

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