JPH11262186A - Controller of power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively compensate for the output fluctuations of a generated power having a plurality of periods with a power storage device. SOLUTION: Compensation values are calculated by a short-period fluctuation compensation unit 32 and a long-period fluctuation compensation unit 33 for respective periods, based on the output fluctuation calculated by a wind power calculation unit 31, and a power command value to a secondary battery 11 is set by adding the sum of the compensation values to a steady charging discharging command value. Control signals to a power converter 12 are generated by a power control unit 34, a current control unit 35 and a pulse generating unit 36, on the basis of the set power command value. The short-period fluctuation compensation unit 32 and the long-period fluctuation compensation unit 33 extract fluctuation period components, which are the compensation objects of the respective compensation units by filters and set with suitable phase compensations and compensation gains to conduct proper fluctuation compensation control which matches the responsiveness and capacity of a power storage system.

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 input or output power of a power storage system such as a secondary battery, and more particularly to a control device suitable for performing output fluctuation compensation of natural energy power generation such as wind power generation. .

[0002]

2. Description of the Related Art In recent years, interconnection of power generation using natural energy such as wind power or sunlight to a power system has been increasing. However, since natural energy fluctuates and power generation output fluctuates, fluctuations in the frequency and voltage of the system due to the influence may be a problem.

Therefore, a method has been devised in which a power storage system such as a secondary battery is used to absorb or discharge power to compensate for fluctuations in power generation output. When the power generation output increases, the power release of the power storage increases or the power absorption decreases, and when the power generation output decreases,
By operating in reverse, fluctuations in the power generation output can be compensated.

[0004] For example, Material P of the Institute of Electrical Engineers of Japan
E-97-111 describes a method of controlling a fluctuation compensation output using a superconducting energy storage device so as to suppress the output fluctuation in a period of 2 to 4 seconds.

[0005]

There are cases where fluctuations in power generation output of natural energy include fluctuations in a plurality of cycles. For example, in the case of wind power generation, 0.5
A fluctuation of a period of 2 seconds and a fluctuation of a period of 10 seconds or more due to a change of wind intensity may be mixed.

[0006] However, in the above-mentioned method, no study has been made on a method for effectively compensating for both fluctuations when a plurality of fluctuations are present.

An object of the present invention is to provide a control device of a power storage device that can exhibit a sufficient fluctuation compensation effect even when power generation output fluctuations in a plurality of cycles are mixed.

[0008]

In order to achieve the above object, a filter means for extracting a fluctuation period component to be compensated and a compensation amount calculating means for determining a fluctuation compensation amount according to the extracted fluctuation period component. Equipped. In addition, a filter means and a compensation amount calculating means are provided for each of a plurality of fluctuation periods, and the respective fluctuation compensation amounts are summed to obtain the entire fluctuation compensation amount.

Thus, it is possible to set appropriate control constants such as compensation gain and phase compensation for each target fluctuation cycle, and to perform effective fluctuation compensation according to the response and capacity of the power storage system. Will be able to

[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 unit 13 includes a wind power calculation unit 31, fluctuation compensation units 32-33, a power control unit 34, and a current control unit 3.
5, a pulse generator 36.

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. Fluctuation compensation units 32-33
Calculates the fluctuation compensation amount based on the calculated value of the wind power. Details will be described later. The sum of the outputs of the fluctuation compensators 32 to 33 and the charge / discharge command value is the active power command value for the battery.

A power control unit (APR: Automatic Power Re
gulator) 34 calculates the actual inverter output power from the voltage and current detected by the system voltage sensor 22 and the inverter current sensor 23, and calculates a deviation from the active power command value.
Based on this, a current command value for the inverter is created.

A current control unit (ACR: Automatic Current)
Regulator) 35 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 as to eliminate the deviation. The pulse generator 36 generates a PWM (Pulse Width) based on the output voltage command value.
Modulation) creates a gate pulse signal of the power converter 12.

Next, the fluctuation compensators 32 to 33 are shown in FIG.
This will be described with reference to FIG. The fluctuation compensator is a short-period fluctuation compensator 32.
And a long-period fluctuation compensating unit 33, each of which includes a filter 41, a phase compensation 42, a gain 43, and a limiter 44. In general, it is said that output fluctuations of wind power include short-period fluctuations of 0.5 to 2 seconds due to the rotation of wings and long-period fluctuations of 10 seconds or more due to fluctuations in wind intensity. , The two fluctuation periods are compensated by independent fluctuation compensation units.

In the short-period fluctuation compensating unit 32, first, a fluctuation component having a period of 0.5 to 2 seconds is extracted by the filter 41, and the phase advance is compensated by the phase compensation 42 in consideration of the response delay of the inverter. As an actual constant value, for example, Ta1 =
0.02, Ta2 = 1.0, Ta3 = 0.02, Ta4 = 0.
04, Ka = 0.9.

In the long-period fluctuation compensating section 33, first, a fluctuation component having a period of 10 seconds or more is extracted by the filter 41. Since the response delay of the inverter has no effect on the long cycle, no phase compensation is required. The gain is determined in consideration of the difference between the capacity of the wind power generation and the capacity of the power storage system. In general, output fluctuations due to wind fluctuations are large, and if the capacity of the power storage system is not large enough, it is necessary to set a small gain so as not to stick to the output limit. . As an example of the constant, Tb1 =
1.0, Tb2 = 30, Tb3 = 1.0, Tb4 = 1.
0, Kb = 0.4, etc.

FIGS. 4 to 6 show examples of simulation of the fluctuation compensating unit set as described above. As a simulated wind power output, as shown in FIG. 4, a fluctuating output was generated by synthesizing signals of 0.5 second, 1.4 second, and 20 second periods, and the effect of fluctuation compensation was verified.

When a simple low-pass filter and a control method using only a gain as shown in FIG. 3 are used, as shown in FIG. 5, the effect of suppressing short-period fluctuation is not sufficiently obtained. In addition, since the maximum output of the battery system is as small as 25 kW, the output is stuck to the limit value due to long-period fluctuation.

In the case of the control method of the present invention (FIG. 2), FIG.
As shown in (1), the short-period fluctuation is sufficiently suppressed, and the long-period fluctuation is exhibited within a small capacity range.

As described above, in the present embodiment, short-period fluctuations of wind power generation can be sufficiently suppressed, and long-period vibrations can also exhibit the effect of suppressing power fluctuations according to the capacity of the power storage system. There is an effect that can be.

[0024]

According to the present invention, when the power storage system compensates for the output fluctuation of the renewable energy power generation, even when the output fluctuations of a plurality of periods are mixed, the capacity of the power storage system is matched. There is an effect that sufficient fluctuation compensation can be performed.

[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 block diagram of a fluctuation compensation unit according to the present invention.

FIG. 3 is a block diagram of a conventional fluctuation compensation unit.

FIG. 4 is a graph showing simulated output fluctuation.

FIG. 5 is a graph showing a fluctuation suppressing effect according to a conventional method.

FIG. 6 is a graph showing a fluctuation suppressing effect of the present method.

[Explanation of symbols]

11 ... secondary battery, 12 ... power converter, 13 ... control device,
14: Transformer for conversion, 15: Wind power generator, 21: Wind current sensor, 22: System voltage sensor, 23: Inverter current sensor, 31: Wind power calculation unit, 32: Short cycle fluctuation compensation unit, 33: Long cycle Fluctuation compensator 34, power controller 3,
5: current controller, 36: pulse generator, 41: filter, 42: phase compensation, 43: gain, 44: limiter.

Claims (2)

[Claims] 1. A control device for controlling an active power input or output to an electric power storage system, comprising: output fluctuation detecting means for detecting power generation output fluctuation from natural energy power generation connected to an electric power system; Fluctuation compensation means for adding a fluctuation compensation amount according to the command value of the active power input or output, the fluctuation compensation means, a filter means for extracting a fluctuation period component to be compensated from the detected output fluctuation, A control device for a power storage system, comprising: a compensation amount calculating unit that determines a variation compensation amount according to an extracted variation period component. 2. The apparatus according to claim 1, wherein said filter means and said compensation amount calculating means are provided for a plurality of fluctuation periods, respectively, and the sum of the respective fluctuation compensation amounts is used as the entire fluctuation compensation amount. Power storage system control device.