JPH11262187A - Controller of power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a power storage system for making a voltage drop compensation function exhibit to the maximum, when a wind power generator is interconnected to a power system. SOLUTION: A mode changeover unit 39 decides on the priority between a charging/discharging function and a voltage compensation function and changes the values of current command limiters 35 and 36. At normal times, the large value of the active current command limiter and a small value of the reactive current command limiter are set, to give priority to the charging discharging functions. When a system interconnection signal is outputted from a wind power generator, the values of the active current command is reduced, and the value of the reactive current command is increased to give priority to the voltage fluctuation compensation function for only a certain period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling the active power and the reactive power of a power storage system such as a secondary battery, and more particularly to an electric power suitable for performing a system voltage fluctuation compensation when a wind power generator is incorporated. The present invention relates to a control device for a storage system.

[0002]

2. Description of the Related Art In recent years, interconnection of wind power generation using natural energy to a power system has been increasing. However, in the case of an induction machine type wind power generator, a large excitation rush current flows when the power generation is incorporated into a system, resulting in a decrease in system voltage. Therefore, a static var compensator (SVC: Static Var Com
A method of suppressing a decrease in system voltage using a pensator or the like has been studied.

On the other hand, a power storage device using a secondary battery or the like absorbs and releases active power for the purpose of load leveling and system stabilization, but absorbs and releases reactive power by controlling a power converter. It is also possible to do. For example, sodium-equipped with multiple functions such as SVC function in addition to charge / discharge function.
An example of a sulfur battery power storage system is described in the 1997 IEEJ Power Energy Division Conference No. 236.

If such a power storage device is used, in addition to the functions of load leveling and system stabilization in normal times, the SVC function can compensate for a system voltage drop when wind power generation is incorporated.

[0005]

However, the reactive current at the time of wind power generation is generally said to be several times the rated current, and a large-capacity SVC is required to compensate for it. If the converter capacity of the power storage system is large enough,
Voltage fluctuation compensation can be performed by outputting reactive power while charging / discharging, but otherwise the current upper limit of the converter is affected and sufficient voltage fluctuation compensation cannot be performed. In order for the voltage fluctuation compensation function to work sufficiently, the charge / discharge function must be suppressed so that a large reactive current can flow. However, the above-described method has not considered how to cope with such a case.

An object of the present invention is to provide a control device of a power storage system that can exhibit a sufficient voltage compensation function when wind power generation is combined.

[0007]

In order to achieve the above object, a control device for controlling power input / output of a power storage system includes a charge / discharge function, a system voltage compensation function, and a charge / discharge function and a system voltage compensation function. And a mode switching unit for determining the priority of the active current command and the limit value of the reactive current command based on the determination result of the priority.

Further, the mode switching means gives priority to the system voltage compensation function when the signal incorporated into the power system of wind power generation is obtained, reduces the limit value of the active current command, and limits the limit value of the reactive current command. Increased the value.

Thus, when the wind power generator is connected to the system, the effective current command is reduced, and the reactive current can be increased accordingly, so that the voltage compensation function can be effectively exhibited.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a secondary battery power storage system to which the present invention is applied. The system includes a secondary battery 11, a power converter 12, and a controller 13, and is connected to a power system via a conversion transformer 14. Further, a wind power generator 15 is connected to the grid as natural energy power generation.

The power converter 12 is constituted by using a semiconductor element such as an IBGT or a diode.
Converts the DC power of the secondary battery 11 into AC power, or vice versa, based on the control signal from.

The control device 13 includes a wind power calculator 31, an output fluctuation compensator 32, a power controller 33, and a voltage fluctuation compensator 3.
4, current command limiters 35 to 36, a current control unit 37, and a pulse generation unit 38. A mode switching unit 3 for switching the values of the current command limiters 35 to 36.
9 is provided.

The wind power calculation unit 31 is provided with the wind current sensor 2
1 and the output power of the wind power generation is calculated based on the current and voltage detected by the system voltage sensor 22. Output fluctuation compensator 32
Calculates the output fluctuation compensation amount based on the calculated value of the wind power. The sum of the output of the output fluctuation compensator 32 and the charge / discharge command value is the active power command value for the battery.

The power control unit 33 outputs the actual inverter output power to the system voltage sensor 22 and the inverter current sensor 23.
Calculated from the detected voltage and current, a deviation from the active power command value is obtained, and an active current command value for the inverter is created based on the deviation (charge / discharge function).

The voltage fluctuation compensating section 34 includes the system voltage sensor 2
2 based on the deviation between the detected voltage value and the voltage reference value,
Create a reactive current command value for the inverter to eliminate the deviation (voltage fluctuation compensation function).

The active current command value and the reactive current command value pass through current command limiters 35 to 36, respectively, and the current control unit 37
Is input to The current control unit 37 calculates a deviation between the inverter current command value and the actual inverter current, and creates an output voltage command value of the power converter so that the deviation is eliminated.
The pulse generator 38 performs PWM based on the output voltage command value.
(Pulse Width Modulation) generates a gate pulse signal of the power converter 12.

The mode switching section 39 determines the priority of the charge / discharge function and the voltage fluctuation compensation function, and
Change the value of 5-36. As a method of determining the priority, for example, a combined signal from the wind power generator 15 is used.
Normally, the charge / discharge function is prioritized, and when a combined signal is issued from the wind power generator 15, the voltage compensation function is prioritized for a certain period (for example, 10 seconds) therefrom.

The setting of the current command limiter according to the priority is as follows. Generally, in a power converter, the upper limit of the magnitude of a current flowing through an element is determined. The magnitude of the current is determined by the vector sum of the active current and the reactive current, and the operable range is represented by a circle as shown in FIG. Therefore, when giving priority to the charge / discharge function, as shown in FIG. 2, for example, the active current command limiter is set to ± 90 A, and the reactive current command limiter is set to ± 43 A. When giving priority to the voltage fluctuation function, for example, the effective current command limiter is set to ± 1.
0A and the reactive current command limiter are set to ± 99A.

As described above, by changing the value of the current command limiter according to the priority, each function can be effectively exerted. In particular, when incorporating wind power,
There is an effect that the voltage compensation effect can be maximized.

When the combined signal from the wind power generator cannot be obtained, it is possible to determine the priority by lowering the system voltage. If the amount of system voltage drop is large and the reactive current command sticks to the limiter,
The voltage compensation function is determined to have priority. In this case, there is an effect that the operation can be performed without providing a special signal line from the wind power generator.

[0022]

According to the present invention, there is an effect that the power storage system can maximize the function of compensating for the system voltage drop when the wind power generator is incorporated into the system.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a secondary battery power storage system to which the present invention is applied.

FIG. 2 is a graph showing an operation range of a power converter.

[Explanation of symbols]

11 ... secondary battery, 12 ... power converter, 13 ... control device,
14: Transformer for transformation, 15: Wind power generator, 21: Wind current sensor, 22: System voltage sensor, 23: Inverter current sensor, 31: Wind power calculation unit, 32: Output fluctuation compensation unit, 33: Power control unit , 34 ... voltage fluctuation compensator, 35 ...
Effective current command limiter, 36 ... reactive current command limiter,
37: current control unit, 38: pulse generation unit, 39: mode switching unit.

Claims (2)

[Claims] 1. A control device for controlling power input / output of a power storage system, comprising: a charge / discharge function; a system voltage compensation function; and mode switching means for determining a priority between the charge / discharge function and the system voltage compensation function. The control device for a power storage system, wherein the mode switching means sets a limit value of an active current command and a reactive current command of the control device based on a priority determination result. 2. The system according to claim 1, wherein the mode switching means gives priority to the system voltage compensation function based on a signal incorporated into a power system of wind power generation, and sets a limit value of an effective current command of the control device. A control device for a power storage system, wherein the control device sets a small limit value of a reactive current command to a large value.