JP2018191393A - Parallel connection storage battery system and control device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong an operable time in parallel operation of storage batteries. SOLUTION: This 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 power a load. It has a plurality of power conversion devices for supplying power and a plurality of storage batteries connected to each of the plurality of power conversion devices, and is based on electrical information of at least one of the output voltage and the remaining capacity of the storage battery. A parallel connection storage battery system characterized by having a control circuit for controlling the output voltage of an inverter connected to the storage battery. [Selection diagram] Fig. 1

Description

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

  Inverter output current detection in parallel operation of multiple inverters connected in parallel with the output of an error amplifier circuit that compares the output voltage with a sine wave reference signal controlled via a PWM drive circuit A means for adding or subtracting the signal to or from the input or output of the error amplifier circuit is provided, whereby when the output voltage of the inverter is lowered, the output current detection signal is added to the signal from the sine wave generation circuit. When the output voltage of the inverter is raised together with the output voltage detection signal, the current detection signal and the voltage detection signal are added, and the signal from the sine wave generation circuit is supplied to the error amplification circuit. There is known an inverter parallel operation method characterized by controlling cross current in (see Patent Document 1).

Japanese Patent Publication No. 6-40704

  In the technique described in Patent Document 1, the output of an inverter is connected to a parallel bus, and 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 the 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 shift in the output voltage signal of the inverter is accumulated, resulting in a large shift in the discharge power amount of the storage battery. Then, the voltage of the storage battery with a large amount of discharged electric power decreases early, and the inverter stops when it becomes equal to or lower than the use input voltage of 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 this invention is to lengthen the operation possible time in the parallel operation of a storage battery.

  According to an aspect of the present invention, there is provided a plurality of power conversion devices including a plurality of DC / DC converters and inverters that convert the output voltage of the DC / DC converter into an AC voltage, and the AC outputs are parallel to each other. A plurality of power converters connected to supply power to the load, and a plurality of storage batteries connected to each of the plurality of power converters, and at least one of the output voltage or remaining capacity of the storage batteries A parallel-connected storage battery system comprising a control circuit for controlling an output voltage of an inverter connected to the storage battery based on electrical information is provided.

The control circuit preferably performs control 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 are equal based on the output voltage of the storage battery.
The control circuit may perform control to change 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 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. Control is good.
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, the output voltage of the inverter connected to the storage battery in a direction in which the remaining capacity of the plurality of storage batteries becomes equal You may make it perform control to change.
The control circuit has 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 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 a node between the DC / DC converter and the inverter, and may have a series connection circuit of a natural energy generator and the converter.
Further, it may be connected to a node between the DC / DC converter and the inverter, and may have a series connection circuit of a commercial power source and an AC / DC converter.

  The present invention is also a plurality of power converters having a plurality of DC / DC converters and inverters that convert the output voltage of the DC / DC converter into an AC voltage, and each AC output is connected in parallel and loaded. A control device of a parallel-connected storage battery system having a plurality of power conversion devices that supply power to the plurality of storage batteries connected to each of the plurality of power conversion devices, the output voltage or remaining capacity of the storage batteries It is a control apparatus of the parallel connection storage battery system which controls the output voltage of the inverter connected to a storage battery based on at least any one electrical information.

  ADVANTAGE OF THE INVENTION According to this invention, the driving | operation possible time in the parallel operation of a storage battery can be lengthened.

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

  Hereinafter, a parallel connection storage battery control technique according to an 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 a parallel connection storage battery control technique according to an 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 output voltages of the DC / DC converters 13,. , 26 having a plurality of power conversion devices 16... The power converters 16,..., 26 connect the 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 conversion devices 16,. The inverter devices 10, ..., 20 are power conversion devices 16, ..., 26 connected to the storage batteries 11, ..., 21, respectively.

  Furthermore, the parallel connection storage battery system 1 includes control circuits 51,..., 61 in the power conversion devices 16,. The control circuits 51,..., 61 are based on the electric information of at least one of the output voltage or the remaining capacity (SOC) of the storage batteries 11,. 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,. The storage battery information processing circuits 53,..., 63 are connected to the inverter output voltage command value (S2) based on the electrical characteristics (S1,..., S11) of the storage batteries 11,. , ..., S21) is output. The inverter voltage control circuits 55,..., 65 are signals (S3,..., S31) for controlling the inverter voltage based on the inverter output voltage command values (S2,..., S21) from the storage battery information processing circuits 53,. ) 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 the 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 a subtracter 161, a proportional control unit 163, and an adder 165 are connected in series.

  The storage battery voltage that can be used as its own electrical information is V1. The reference value Vs is, for example, the center voltage in the operating range of the storage battery 11. The subtracter 161 subtracts the reference value Vs of the storage battery voltage from the storage battery voltage V1 to obtain a 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 output voltage effective 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. When the storage battery voltage V1 is higher than the reference value Vs, the inverter output voltage command value Vinv1 is increased. When the storage battery voltage V1 is lower than the reference value Vs, the inverter output voltage command value Vinv1 is corrected to be decreased. 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 to the load 31 of the inverter 15.

  In the parallel-connected storage battery system 1 shown in FIG. 1 and FIG. 2A, the control circuits 51,..., 61 monitor the voltages of the storage batteries 11, ..., 21 and based on the voltages of the storage batteries 11,. , 25 output voltage is changed. Then, the control circuits 51,..., 61 perform control so that the voltages of the respective storage batteries 11,. The details of the control will be described below.

When the voltage of its own storage battery is high, the output voltage of the inverter is changed in the higher direction. Then, the load sharing amount of its own inverter increases. Therefore, the discharge power from the storage battery increases, and the voltage drop of the own storage battery is accelerated. As a result, the voltage of each storage battery becomes equal.
On the other hand, when the voltage of its own storage battery is low, the output voltage of the inverter is changed in a lower direction. Then, the load sharing amount of its own inverter is reduced. 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 its own electrical information. However, as shown in FIG. 2B, the battery capacity SOC ( 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 center SOC in the operation range of the storage battery can be used.

  Proportional control unit 163 amplifies or attenuates the difference between storage battery calculated capacity SOC1 and storage battery calculated capacity reference value SOCs.

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

(Second Embodiment)
A second embodiment of the present invention will be described. 3A is a functional block diagram showing a configuration example of the storage battery information processing circuit 53 (..., 63) that controls the inverter devices 10, ..., 20 according to the first embodiment, and storage battery information shown in FIG. 2B. 3 is a diagram corresponding to a processing circuit 53. FIG. 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 in 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,.

  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.

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.

  Then, the output of the subtracter 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 and the reference sine wave Ws. The subtracter 93 subtracts the output from the inverter output voltage detector 81 from the output of the multiplier 91 and amplifies the output by the amplifier 95.

  The subtracter 97 subtracts the output of the amplifier 95 from the output of the inverter output current detector 99 and outputs the result to the PWM signal generation circuit 101. The output of the PWM signal generation circuit 101 is an inverter gate signal.

  As described above, the inverter output voltage detection in which the output voltage of the inverter is detected by a voltage detector (not shown) is converted into an effective value by the effective value circuit 83. A differential voltage between the signal converted into 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 so that the differential voltage signal becomes zero.

  That is, a reference sine wave that is controlled so that the effective value of the inverter output voltage is equal to the inverter output voltage command value is sent from a circuit that matches the output frequency and phase of the inverter of each device, although not described here. The reference sine wave of the inverter to be used.

  The differential voltage signal amplified by the PI control is multiplied by a reference sine wave to become an 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 inverter gate signal 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.

  Note that subtracting the inverter output current detection signal from the output of the amplifier is, for example, a technique disclosed in Japanese Patent Publication No. 6-40704, and can control cross current between inverters.

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

(Third embodiment)
FIG. 5: is a functional block diagram which shows the example of 1 structure of the parallel connection storage battery system using the parallel connection storage battery control technique by the 3rd Embodiment of this invention.
Unlike the circuit configuration shown in FIG. 1, in the circuit configuration 201 shown in FIG. 5, solar cells 210,..., 220 and converters 213,. It differs in that it is. Other configurations are the same as those in FIG. The power converters are indicated by reference numerals 16a and 26a.

The solar cell may use renewable power such as a rechargeable battery based on geothermal power generation that can be regenerated by other natural energy.
In a system including a solar battery, the storage battery is charged by power generation from the solar battery. Therefore, the operation time of the inverter in consideration of charging from the solar battery is assumed. Since the operation time of this parallel-connected storage battery system is longer than that of the other examples, the accumulation of the difference in discharge power is further increased, and the rate at which the operation time is shortened compared to the assumed operation time is increased.
Therefore, the system as shown in FIG. 5 has 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 to the configuration shown in FIG. 1, in the configuration shown in FIG. 6, commercial power sources (AC power sources) 310,..., 320 and converters 213,. It is different in having. Other configurations are the same as those in FIG. The power converter is indicated by reference numerals 16b,... 26b.
The system shown in FIG. 6 has the advantage that it can be operated with a storage battery when the commercial power supply becomes unavailable during a power failure.

In the above-described embodiment, the configuration and the like illustrated in the accompanying drawings are not limited to these, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention. For example, it is needless to say that different circuits having the same function may be used as circuit components.
Each component of the present invention can be arbitrarily selected, and an invention having a selected configuration is also included in the present invention.

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

DESCRIPTION OF SYMBOLS 1 ... Parallel connection storage battery system, 10 ... Inverter apparatus, 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 (9)

A plurality of power conversion devices having a plurality of DC / DC converters and inverters for converting the output voltage of the DC / DC converters into AC voltages, and supplying power to a load by connecting the AC outputs in parallel. And a plurality of storage batteries connected to each of the plurality of power conversion devices,
A parallel-connected storage battery system comprising a control circuit that controls an output voltage of an inverter connected to the storage battery based on electrical information of at least one of the output voltage and remaining capacity of the storage battery. The control circuit includes:
The parallel connection storage battery system of Claim 1 which performs control which changes the output voltage of the said inverter connected to the said storage battery in the direction in which the output voltage of the said several storage battery becomes equal based on the output voltage of the said storage battery. The control circuit includes:
The parallel connection storage battery system of Claim 1 which performs control which changes the output voltage of the said inverter connected to the said storage battery in the direction in which the remaining capacity of the said several storage battery becomes equal based on the remaining capacity of the said storage battery. The control circuit includes:
The control is performed 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 based on the difference between the output voltage of the storage battery and the average value of all the storage battery voltages. The parallel connection storage battery system according to 1. The control circuit includes:
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, control is performed to change the output voltage of the inverter connected to the storage battery in a direction in which the remaining capacity of the plurality of storage batteries becomes equal. The parallel connection storage battery system according to claim 1. The control circuit has a storage battery information processing circuit and an inverter voltage control circuit,
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 parallel-connected storage battery system according to any one of claims 1 to 5, wherein the inverter voltage control circuit controls an inverter voltage based on the inverter output voltage command value from the storage battery information processing circuit.   Furthermore, the parallel connection storage battery system of any one of Claim 1-6 connected to the node of the said DC / DC converter and the said inverter, and having a series connection circuit of a natural energy generator and a converter.   Furthermore, the parallel connection storage battery system of any one of Claim 1-5 which has a serial connection circuit of a commercial power supply and an AC / DC converter connected to the node of the said DC / DC converter and the said inverter. A plurality of power conversion devices having a plurality of DC / DC converters and inverters for converting the output voltage of the DC / DC converters into AC voltages, and supplying power to a load by connecting the AC outputs in parallel. A parallel-connected storage battery system control device having a plurality of storage batteries connected to each of the plurality of power conversion devices,
The control apparatus of the parallel connection storage battery system which controls the output voltage of the inverter connected to a storage battery based on the electrical information of at least any one of the output voltage or remaining capacity of the said storage battery.

Images