Power systems and control devices for power systems

Abstract

This invention provides a power system that allows for arbitrary control of the active and reactive power of an AC / DC converter. [Solution] A power system comprising: a first control unit that calculates the difference between the effective value of active power and the effective power offset value, and the difference between the effective value of reactive power and the reactive power offset value; a second control unit that calculates a first target value which is the difference between the average value of active power and the average value of active power offset values ​​obtained based on the calculation results of the first control unit, and a second target value which is the difference between the average value of reactive power and the average value of reactive power offset values; and a third control unit that determines a voltage control target value from the difference between the first target value and the effective value of active power of the AC / DC converter, and the difference between the second target value and the effective value of reactive power of the AC / DC converter, wherein the power system has a control controller that controls the active power and reactive power of the AC / DC converter by commanding each of the AC / DC converters with the voltage control target value.

Description

[Technical Field]

[0001] The present invention relates to a power system and a control device for a power system. [Background technology]

[0002] A method for autonomously and distributedly controlling the balance of current and power of inverter power supplies connected to an AC bus line has been disclosed (Patent Document 1). In this technology, the average values ​​of the active current and reactive current are obtained via communication, and the active current and reactive current of each inverter power supply are controlled to be equal to the average value. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-161868 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In AC microgrids independent of the power grid, distributed power sources such as stationary batteries, electric vehicles, and solar panels are considered promising as grid-controlled power sources. It is envisioned that multiple distributed power sources will be connected to a single microgrid via AC / DC converters.

[0005] Incidentally, if there is variation in the impedance of the wiring between each AC / DC converter and the grid of the AC bus line, the output voltages of each AC / DC converter will not be equal even if the active current and reactive current are equal. This can lead to significant variations in active power and reactive power.

[0006] Furthermore, it is desirable to be able to change the distribution ratio of active power and reactive power according to the rated power of the inverter power supply and the capacity of the battery connected to the inverter power supply. However, the conventional technology described above assumes a power system in which the same power supply is connected in parallel, and is configured to follow the average value of the active current and reactive current, making it impossible to change the power distribution ratio.

[0007] Furthermore, in order to control the charging and discharging of batteries connected to the inverter power supply according to the state of charge (SOC) and usage schedule, it is desirable to be able to individually adjust the offset amounts of the active power and reactive power of each AC / DC converter. However, in the conventional technology described above, power offset control is impossible because the system is configured to follow the average value of the active current and reactive current.

[0008] Furthermore, in the conventional technology described above, instantaneous voltage control is performed by determining the phase using the active current deviation and the voltage amplitude using the reactive current deviation. However, when the wiring impedance is small, such as in short-distance wiring, the current change in response to phase and voltage changes becomes large, making control prone to failure.

[0009] As shown in Figure 12, a simulation was conducted when two AC / DC converters applying the above prior art were operated in a power system with wiring impedance assuming short-distance wiring of approximately 5 to 10 m in length. At the start of the simulation, the units were operated without load, and 10 seconds after the start, the switches were turned on and a load of 10 + j 10 Ω was connected to the AC bus line. Figure 13 shows the simulation results of the active power (P1, P2) and reactive power (Q1, Q2) of each AC / DC converter. The control failed because it was not possible to control the active and reactive power to be equal to the average value of the two AC / DC converters.

[0010] Another existing method for controlling load sharing between AC / DC converters is droop control. This method controls the voltage amplitude based on the active power of the AC / DC converters and the frequency based on the reactive power, under the condition that the wiring impedance is resistive. However, a problem with this control is that if the wiring resistance between each AC / DC converter and the AC bus line is mismatched, the output voltages from each AC / DC converter will be different, resulting in errors in the distribution of active power. [Means for solving the problem]

[0011] One aspect of the present invention relates to a power system comprising an AC / DC converter having an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, wherein the system comprises a first control unit that calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters, and the first control unit The power system is characterized by having a control controller that controls the active power and reactive power of the AC / DC converter by commanding each of the AC / DC converters with the voltage control target value. This control controller comprises a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results in the above, and a second target value which is the difference between the average reactive power value and the average reactive power offset value, and a third control unit which determines a voltage control target value from the difference between the first target value and the effective active power value of the AC / DC converter, and the difference between the second target value and the effective reactive power value of the AC / DC converter.

[0012] Another aspect of the present invention relates to a power system comprising an AC / DC converter having an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, wherein the system comprises: a first control unit that calculates the effective active power value calculated from the voltage and current for each of the AC / DC converters, and the effective reactive power value calculated from the voltage and current for each of the AC / DC converters; a first target value obtained by weighting the average active power value obtained from the effective active power value by the number of AC / DC converters and an arbitrary active power distribution ratio; and the AC / DC The power system is characterized by having a control controller that controls the active power and reactive power of each AC / DC converter by commanding each AC / DC converter with the voltage control target value, and further comprising: a second control unit that calculates a second target value weighted by the number of AC / DC converters and an arbitrary reactive power distribution ratio; a third control unit that determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each AC / DC converter, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each AC / DC converter, and a control controller that controls the active power and reactive power of each AC / DC converter by commanding each AC / DC converter with the voltage control target value.

[0013] Another aspect of the present invention relates to a power system comprising an AC / DC converter having an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, wherein the system comprises a first control unit that calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters, and the difference between the average effective power value and the average effective power offset value obtained based on the calculation results of the first control unit, with respect to the number of AC / DC converters and an arbitrary effective power distribution ratio. The power system is characterized by having a control controller that controls the active power and reactive power for each of the AC / DC converters by commanding the AC / DC converters with the voltage control target value, and further comprising: a second control unit that calculates a second target value which is weighted by the number of AC / DC converters and an arbitrary reactive power distribution ratio, based on the difference between the weighted first target value and the average value of the average reactive power and the average value of the reactive power offset obtained from the calculation results of the first control unit; and a third control unit that determines a voltage control target value from the difference between the value obtained by weighting the first target value by the active power distribution ratio and the effective active power of each of the AC / DC converters, and the difference between the value obtained by weighting the second target value by the reactive power distribution ratio and the effective reactive power of each of the AC / DC converters.

[0014] Here, the system preferably includes a single centralized control controller that implements the second control unit, and distributed control controllers equal to the number of AC / DC converters that implement the first control unit and the third control unit, wherein the centralized control controller and the distributed control controllers are each connected to a communication line, and each of the distributed control controllers transmits to the centralized control controller the difference between the effective value of active power and the effective power offset value, and the difference between the effective value of reactive power and the reactive power offset value, and the centralized control controller transmits to each of the distributed control controllers a weighted value of the difference between the average value of active power and the average value of active power offset, and a weighted value of the difference between the average value of reactive power and the average value of reactive power offset, and each of the AC / DC converter input / output controllers transmits to the centralized control controller voltage and current for each of the AC / DC converters, and the centralized control controller transmits to each of the AC / DC converter input / output controllers the voltage control target value or the current control target value obtained from the voltage control target value.

[0015] Furthermore, it is preferable to include a distributed control controller equal to the number of AC / DC converters on which the first control unit, the second control unit, and the third control unit are implemented, wherein the distributed control controllers are connected by communication lines, and each of the distributed control controllers transmits the effective active power value and the effective reactive power value for each of the AC / DC converters to the other distributed control controllers.

[0016] Furthermore, it is preferable to have a control controller that further includes a fourth control unit which determines a current control target value using a controller that includes an integrator determined from the voltage of each of the AC / DC converters and the voltage of the voltage of the third control unit, and controls the active power and reactive power of each of the AC / DC converters by commanding each of the AC / DC converters with the current control target value.

[0017] Another aspect of the present invention relates to a control device for a power system having an AC / DC converter having an AC / DC converter input / output controller and an AC bus in which a plurality of devices having power supplies capable of input and output are connected in parallel, the control device comprising: a first control unit that calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters, and The power system control device comprises: a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results of the first control unit; a second target value which is the difference between the average reactive power value and the average reactive power offset value; and a third control unit which determines a voltage control target value from the difference between the first target value and the effective active power value of the AC / DC converter, and the difference between the second target value and the effective reactive power value of the AC / DC converter; and controls the active power and reactive power of the AC / DC converter by commanding each of the AC / DC converters with the voltage control target value.

[0018] Another aspect of the present invention is a control device for a power system having an AC / DC converter having an AC / DC converter input / output controller and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, wherein the control device includes a first control unit that calculates the effective active power value calculated from the voltage and current for each of the AC / DC converters, and the effective reactive power value calculated from the voltage and current for each of the AC / DC converters, and a first target value obtained by weighting the average active power value obtained from the effective active power value by the number of AC / DC converters and an arbitrary active power distribution ratio, and the average reactive power value obtained from the effective reactive power value The power system control device comprises: a second control unit that calculates a second target value weighted by the number of AC / DC converters and an arbitrary reactive power distribution ratio; and a third control unit that determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters; and controls the active power and reactive power of each of the AC / DC converters by commanding the voltage control target value to each of the AC / DC converters.

[0019] Another aspect of the present invention relates to a control device for a power system having an AC / DC converter having an AC / DC converter input / output controller and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, the control device comprising: a first control unit that calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters, and the number of AC / DC converters and an arbitrary effective A power system control device comprising: a second control unit that calculates a second target value weighted by the number of AC / DC converters and an arbitrary reactive power distribution ratio based on a first target value weighted by the power distribution ratio and the difference between the average reactive power value and the average reactive power offset value obtained from the calculation results of the first control unit; and a third control unit that determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each AC / DC converter, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each AC / DC converter, wherein the active power and reactive power are controlled for each AC / DC converter by commanding the AC / DC converters with the voltage control target value. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a power system and a control device for the power system that can arbitrarily control the active power and reactive power of an AC / DC converter. [Brief explanation of the drawing]

[0021] [Figure 1] This figure shows the configuration of a power system in an embodiment of the present invention. [Figure 2]This figure shows the configuration of a control controller for a power system in an embodiment of the present invention. [Figure 3] This figure shows the configuration of a control controller for a power system in an embodiment of the present invention. [Figure 4] This figure shows the configuration used in the simulation of a power system according to an embodiment of the present invention. [Figure 5] This figure shows the results of a simulation of a power system in an embodiment of the present invention. [Figure 6] This figure shows the results of a simulation of a power system in an embodiment of the present invention. [Figure 7] This diagram shows the configuration of the power system control controller in Modification Example 1. [Figure 8] This diagram shows the configuration of the power system control controller in modified example 2. [Figure 9] This diagram shows the configuration of the power system control controller in modified example 3. [Figure 10] This diagram shows the configuration of the power system control controller in modified example 4. [Figure 11] This figure shows a specific example of the power system configuration in Modification Example 5. [Figure 12] This figure shows a specific example of the configuration of a conventional power system. [Figure 13] This figure shows the results of a simulation of a conventional power system. [Modes for carrying out the invention]

[0022] As shown in Figure 1, the power system 100 in the embodiment of the present invention comprises an ACDC converter 10 (10a to 10n), an input / output controller 12 (12a to 12n), a current controller 14 (14a to 14n), and a power reference value calculation unit 16. The current controller 14 (14a to 14n) and the power reference value calculation unit 16 together function as a control controller 18.

[0023] The input / output controller 12 and the current controller 14 are provided in the same number as the number of ACDC converters 10 that are the control targets. In the example of the power system 100 shown in FIG. 1, for n ACDC converters 10 (10a to 10n), input / output controllers 12 (12a to 12n) and current controllers 14 (14a to 14n) are provided respectively.

[0024] In the following description, for the power, voltage, and current related to the first ACDC converter 10a, input / output controller 12a, and current controller 14a, a number 1 is added to the symbol for indication. Similarly, for the power, voltage, and current related to the nth ACDC converter 10n, input / output controller 12n, and current controller 14n, a number n is added to the symbol for indication. Also, when explaining the common functions, the nth ACDC converter 10n, input / output controller 12n, current controller 14n, and power reference value calculation unit 16 are described as representatives.

[0025] The ACDC converter 10n is a circuit that performs AC-DC conversion between the DC power source and the AC bus connected thereto. The DC power source is not particularly limited, and for example, it can be a secondary battery, a solar cell, a fuel cell, or the like.

[0026] The input / output controller 12n controls the output voltage V and the output current I ACDCn output from the ACDC converter 10n based on the current target value I refn input from the current controller 14n so that the output current I ACDCn becomes the current target value I ACDCn . Alternatively, when the current controller 14n is not provided, the input / output controller 12n controls the output voltage V refn and the output current I ACDCn output from the ACDC converter 10n based on the target voltage value V refn input from the power reference value calculation unit 16 so that the output voltage V ACDCn becomes the target voltage value V ACDCn .

[0027] The current controller 14n outputs the output voltage V ACDCnand output current I ACDCn Upon receiving the detected values, these values ​​are output to the power reference value calculation unit 16. Furthermore, the power reference value calculation unit 16 outputs the target voltage value V refn In response, the target voltage value V refn Current target value I refn It generates and outputs to the input / output controller 12n. Note that the target voltage value V refn In a configuration where the AC / DC converter 10n is controlled based on this, the current controller 14n is not required.

[0028] The power reference value calculation unit 16 calculates the output voltage V ACDCn and output current I ACDCn Based on the detected value, the target voltage value V for controlling the ACDC converter 10n is determined. refn The process for generating the power reference value is described below.

[0029] [Control Controller Configuration and Functions] Figure 2 is a diagram showing the configuration of the power system 100, with a detailed representation of the power reference value calculation unit 16. The power reference value calculation unit 16 consists of a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n).

[0030] The first control unit 16-1 and the third control unit 16-3 are provided in the same number as the number of ACDC converters 10 to be controlled. In the example of the power system 100 shown in Figure 2, the first control unit 16-1 (16-1a to 16-1n) and the third control unit 16-3 (16-3a to 16-3n) are provided for each of the n ACDC converters 10 (10a to 10n).

[0031] The power reference value calculation unit 16 is configured to achieve the distribution of active and reactive power according to a desired power distribution ratio and power offset, regardless of the wiring impedance of the power system 100.

[0032] In the first control unit 16-1n, the output voltage V of the AC / DC converter 10nACDCn and output current I ACDCn The active power output P depends on the measured value. ACDCn and reactive power output Q ACDCn To determine the value of the active power output P, ​​when setting a power offset on the output of the AC / DC converter 10n, ACDCn From the active power offset value P refn Subtracting this, the reactive power output Q ACDCn The reactive power offset value Q refn The process involves subtracting the active power offset value P. refn and reactive power output Q ACDCn These can each be set independently to a positive or negative value. The first control unit 16-1n determines the effective power output P ACDCn and reactive power output Q ACDCn This is output to the second control unit 16-2 and the third control unit 16-3n.

[0033] The second control unit 16-2 is configured to include an active power reference value calculation unit 16-2p and a reactive power reference value calculation unit 16-2q.

[0034] The active power reference value calculation unit 16-2p calculates the active power output P obtained by the first control unit 16-1 (16-1a to 16-1n) corresponding to each of the AC / DC converters 10 (10a to 10n). ACDC (P ACDC1 ~P ACDCn ) and the active power output P is calculated using equation (1). ACDC (P ACDC1 ~P ACDCn Calculate the first target value weighted by ).

number

[0035] Here, the average value of the active power output P mean and the average value of the active power offset P refmean These are expressed by equations (2) and (3), respectively. Also, the coefficient K pk These are the active power outputs P, respectively. ACDCk This is a weighting coefficient for setting the active power distribution ratio.

number

number

[0036] The active power reference value calculation unit 16-2p outputs the calculated first target value to the third control units 16-3 (16-3a to 16-3n) corresponding to each of the AC / DC converters 10 (10a to 10n).

[0037] Furthermore, the reactive power reference value calculation unit 16-2q calculates the reactive power output Q obtained by the first control unit 16-1 (16-1a to 16-1n) corresponding to each of the AC / DC converters 10 (10a to 10n). ACDC (Q ACDC1 ~Q ACDCn ) and the reactive power output Q is calculated using equation (4). ACDC (Q ACDC1 ~Q ACDCn Calculate a second target value weighted by ).

number

[0038] Here, the average value of the reactive power output Q mean and reactive power offset average value Q refmean These are expressed by equations (5) and (6), respectively. Also, the coefficient K qk These are the reactive power outputs Q, respectively. ACDCk This is a weighting coefficient for setting the reactive power distribution ratio.

number

number

[0039] The reactive power reference value calculation unit 16-2q outputs the calculated second target value to the third control units 16-3 (16-3a to 16-3n) corresponding to each of the AC / DC converters 10 (10a to 10n).

[0040] When the third control unit 16-3n receives the first target value and the second target value from the second control unit 16-2, it outputs an active power output P for each of them. ACDCk Weighting coefficient K for setting the active power distribution ratio pk and reactive power output Q ACDCk Weighting coefficient K for setting the reactive power distribution ratio qk The value obtained by multiplying by the first control unit 16-1n is the effective power output P ACDCn and reactive power output Q ACDCn The process involves subtracting from to find the difference. Furthermore, the calculated difference value is input to the PI controller, and the voltage target value V is set. refn The third control unit 16-3n calculates the calculated voltage target value V. refn This is output to the input / output controller 12n.

[0041] As described above, the input / output controller 12n receives the target voltage value V from the power reference value calculation unit 16. refn Based on this, the output voltage V output from the ACDC converter 10n is V. ACDCn The target voltage value V refn Output voltage V ACDCn and output current I ACDCn Control.

[0042] As described above, the power system 100 in this embodiment can accurately distribute active and reactive power according to a desired power distribution ratio and power offset, regardless of the wiring impedance.

[0043] Furthermore, as shown in Figure 3, the control controller 18 may also include current controllers 14 (14a to 14n). The number of current controllers 14 is equal to the number of ACDC converters 10 that are to be controlled. In the example of the power system 100 shown in Figure 3, there are n ACDC converters 10 (10a to 10n), each of which has a current controller 14 (14a to 14n).

[0044] The current controller 14n receives the target voltage value V from the third control unit 16-3n. refnBased on this, the target voltage value V refn Output voltage V ACDCn After subtracting that value, the difference is input to the PI controller to set the current target value I refn The current controller 14n outputs the calculated current target value I. refn This is output to the input / output controller 12n.

[0045] The input / output controller 12n receives the current target value I from the control controller 18. refn Based on this, the output current I output from the AC / DC converter 10n ACDCn Current target value I refn Output voltage V ACDCn and output current I ACDCn Control.

[0046] Circuit simulations were performed to confirm that the desired power distribution could be achieved with the configuration of the power system 100 shown in Figures 1 and 3. Figure 4 shows the circuit diagram used in the simulation.

[0047] Two AC / DC converters 10 are connected to the AC bus with different wiring impedances (0.1 + j0.1Ω, 0.2 + j0.2Ω). The simulation was started with no load, and 10 seconds after the start, the switches were turned on and a load of 10 + j10Ω was connected to the AC bus and the simulation was performed. The active power distribution ratio was also considered (K p1 ,K p2 )=(1,2), for the reactive power distribution ratio (K q1 ,K q2 We set ) = (1,2).

[0048] Figure 5 shows the active power (P1, P2) and reactive power (Q1, Q2) of AC / DC converters 10a and 10b, respectively. After 15 seconds, when the load was connected to the AC bus and the active and reactive powers stabilized, the ratio of active power P1:P2=1:2 and the ratio of reactive power Q1:Q2=1:2 respectively, achieving the desired power distribution ratio.

[0049] Also, regarding the active power offset values of each of the AC-DC converters 10a and 10b (P ref1 , P ref2 ) = (1000, 0), and regarding the reactive power offset values (Q ref1 , Q ref2 ) = (1000, 0), a simulation was performed. FIG. 6 shows the active power (P1, P2) and reactive power (Q1, Q2) of each of the AC-DC converters 10a and 10b. An offset of 1000 W was applied to each of the active power and reactive power.

[0050] As described above, it was confirmed that the power system 100 in the embodiment of the present invention performs the desired operation.

[0051] [Modification Example 1] FIG. 7 shows the configuration of the power system 100 when power distribution is not set in a plurality of AC-DC converters 10.

[0052] The power reference value calculation unit 16 includes a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n). The first control unit 16-1 and the third control unit 16-3 are provided in the same number as the number of AC-DC converters 10 that are the control targets.

[0053] In the first control unit 16-1n, the active power output P ACDCn and the reactive power output Q ACDCn are obtained according to the measured values of the output voltage V ACDCn and the output current I ACDCn of the AC-DC converter 10n. Further, when a power offset is set for the output of the AC-DC converter 10n, the active power offset value P ACDCn is subtracted from the active power output P refn , and the reactive power offset value Q ACDCn is subtracted from the reactive power output Q refn . The active power offset value P refn and the reactive power output Q ACDCncan be independently set to a positive value or a negative value. The first control unit 16-1n outputs the obtained active power output P ACDCn and the reactive power output Q ACDCn to the second control unit 16-2 and the third control unit 16-3n.

[0054] The second control unit 16-2 is configured to include an active power reference value calculation unit 16-2p and a reactive power reference value calculation unit 16-2q.

[0055] The active power reference value calculation unit 16-2p receives the active power output P ACDC (P ACDC1 ~P ACDCn ) obtained by the first control unit 16-1(16-1a~16-1n) corresponding to each of the ACDC converters 10(10a~10n), and calculates its average value P mean . Further, the average value P refn of the active power offset value P refmean is calculated. Then, as the difference value of these values, the average value P mean of the active power output is subtracted from the average value P refmean of the active power offset value, and the result is output to the third control unit 16-3(16-3a~16-3n) as the first target value.

[0056] The reactive power reference value calculation unit 16-2q receives the reactive power output Q ACDC (Q ACDC1 ~Q ACDCn [[ID=3८]]) obtained by the first control unit 16-1(16-1a~16-1n) corresponding to each of the ACDC converters 10(10a~10n), and calculates its average value Q mean . Further, the average value Q refn of the reactive power offset value Q refmean is calculated. Then, as the difference value of these values, the average value Q mean of the reactive power output is subtracted from the average value Q refmean of the reactive power offset value, and the result is output to the third control unit 16-3(16-3a~16-3n) as the second target value.

[0057] The third control unit 16-3n determines the first target value and the second target value of the active power output P obtained by the first control unit 16-1n. ACDCn and reactive power output Q ACDCn The process involves subtracting from to find the difference. Furthermore, the calculated difference value is input to the PI controller, and the voltage target value V is set. refn The third control unit 16-3n calculates the calculated voltage target value V. refn This is output to the input / output controller 12n.

[0058] As described above, the input / output controller 12n receives the target voltage value V from the power reference value calculation unit 16. refn Based on this, the output voltage V output from the ACDC converter 10n is V. ACDCn The target voltage value V refn Output voltage V ACDCn and output current I ACDCn Control.

[0059] Furthermore, as shown in Figure 3, a current controller 14 (14a~14n) is provided to set the target voltage value V refn From current target value I refn It may also be configured to calculate and output the current target value I input from the control controller 18. In this case, the input / output controller 12n receives the current target value I from the control controller 18. refn Based on this, the output current I output from the AC / DC converter 10n ACDCn Current target value I refn Output voltage V ACDCn and output current I ACDCn Control.

[0060] [Differentiation 2] Figure 8 shows the configuration of the power system 100 when no power offset is set in the multiple AC / DC converters 10.

[0061] The power reference value calculation unit 16 is composed of a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n). The first control unit 16-1 and the third control unit 16-3 are provided in the same number as the number of ACDC converters 10 to be controlled.

[0062] In the first control unit 16-1n, the output voltage V of the AC / DC converter 10n ACDCn and output current I ACDCn The active power output P depends on the measured value. ACDCn and reactive power output Q ACDCn The first control unit 16-1n determines the effective power output P. ACDCn and reactive power output Q ACDCn This is output to the second control unit 16-2 and the third control unit 16-3n.

[0063] The second control unit 16-2 is composed of an active power reference value calculation unit 16-2p and a reactive power reference value calculation unit 16-2q. In this modified example 2, the active power reference value calculation unit 16-2p and the reactive power reference value calculation unit 16-2q perform the same processing as the power system 100 shown in Figure 2. The third control unit 16-3n processes the first target value and the second target value input from the second control unit 16-2. In this modified example 2, the third control unit 16-3n performs the same processing as the power system 100 shown in Figure 2. The input / output controller 12n then processes the target voltage value V input from the power reference value calculation unit 16. refn Based on this, the output voltage V output from the ACDC converter 10n is V. ACDCn The target voltage value V refn Output voltage V ACDCn and output current I ACDCn Control.

[0064] Furthermore, as shown in Figure 3, a current controller 14 (14a~14n) is provided to set the target voltage value V refn From current target value I refn It may also be configured to calculate and output the current target value I input from the control controller 18. In this case, the input / output controller 12n receives the current target value I from the control controller 18. refn Based on this, the output current I output from the AC / DC converter 10n ACDCn Current target value I refn Output voltage V ACDCn and output current I ACDCn Control.

[0065] [Difference 3] Figure 9 shows the configuration of the power system 100 in modified example 3. In the power system 100 of modified example 3, the control controller 18 is configured to include a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n).

[0066] In the power system 100 of the modified example 3, information is exchanged between the second control unit 16-2 (16-2p, 16-2q), the first control unit 16-1 (16-1a to 16-1n), and the third control unit 16-3 (16-3a to 16-3n) via a communication line (CL). In communication via the communication line (CL), the information may be digitized before communication, or it may be communicated as an analog signal.

[0067] The processing in the first control unit 16-1 (16-1a to 16-1n), the second control unit 16-2 (16-2p, 16-2q), and the third control unit 16-3 (16-3a to 16-3n) is the same as that of the power system 100 shown in Figure 2, so no explanation is provided. Furthermore, as shown in Figure 3, a current controller 14 (14a to 14n) is provided to control the target voltage value V refn From current target value I refn You may also perform control by seeking this value.

[0068] In the present invention, a communication line is used, but the second control unit 16-2 is provided in common for multiple ACDC converters 10 (10a to 10n), which reduces the manufacturing cost of the power system 100.

[0069] [Differentiation Example 4] Figure 10 shows the configuration of the power system 100 in modified example 4. In the power system 100 of modified example 3, the control controller 18 is configured to include a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2a to 16-2n: 16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n).

[0070] In the power system 100 of Modified Example 4, a second control unit 16-2 (16-2a to 16-2n: 16-2p, 16-2q) is provided for each of the ACDC converters 10 (10a to 10n). That is, in the power system 100 of Modified Example 4, the second control units 16-2n are distributed for each of the ACDC converters 10n.

[0071] Information is exchanged between the first control unit 16-1 (16-1a to 16-1n) and the second control unit 16-2 (16-2p, 16-2q) via a communication line (CL). In communication via the communication line (CL), the information may be transmitted digitized or as an analog signal.

[0072] The first control unit 16-1n outputs an active power output P to each of the second control units 16-2 (16-2a to 16-2n) via the communication line (CL). ACDCn and reactive power output Q ACDCn The second control unit 16-2n receives the active power output P from all first control units 16-1 (16-1a to 16-1n). ACDCn and reactive power output Q ACDCn Receive and process the data.

[0073] The processing in the first control unit 16-1 (16-1a to 16-1n), the second control unit 16-2 (16-2a to 16-2n: 16-2p, 16-2q), and the third control unit 16-3 (16-3a to 16-3n) is the same as that of the power system 100 shown in Figure 2, so no explanation is given. Furthermore, as shown in Figure 3, a current controller 14 (14a to 14n) is provided to control the target voltage value V refn From current target value I refn You may also perform control by seeking this value.

[0074] In this way, by using communication lines and providing a second control unit 16-2 for each of the ACDC converters 10 (10a to 10n), distributed control can be achieved, including the second control unit 16-2. Distributed control reduces the computational load on the second control unit 16-2, which is the higher-level controller, and eliminates the need for high-frequency communication.

[0075] [Difference 5] Figure 10 shows the configuration of the power system 100 in Modification Example 5. In the power system 100 of Modification Example 5, the ACDC converter 10 (10a~10n) and the control controller 18 are connected by a communication device (communication line). In communication via the communication device (communication line), information may be digitized before communication, or it may be communicated as an analog signal.

[0076] The configuration of the control controller 18 includes a current controller 14 (14a to 14n) and a power reference value calculation unit 16. The power reference value calculation unit 16 may be configured in the same way as in any of the above embodiments and modified examples, and includes a first control unit 16-1 (16-1a to 16-1n), a second control unit 16-2 (16-2a to 16-2n: 16-2p, 16-2q), and a third control unit 16-3 (16-3a to 16-3n). Note that a configuration without the current controller 14 is also possible.

[0077] [Technical effects] According to the power systems in the embodiments and various modifications of the present invention, it is possible to provide a power system and a control device (control controller) for the power system that can arbitrarily control the active power and reactive power of an AC / DC converter. Specifically, the control loop includes control terms that can control the power distribution ratio and power offset of the active power and reactive power, respectively, so that the distribution ratio and offset of the active power and reactive power of the AC / DC converter can be arbitrarily controlled.

[0078] Furthermore, the power systems in the embodiments and various modifications of the present invention are applicable to AC microgrids using various types of power sources.

[0079] Furthermore, within the control of the AC / DC converter, a control system including an integrator determines the current command value based on the voltage command value. This suppresses current changes in response to changes in phase and voltage amplitude command values, even in systems with low wiring impedance, enabling stable control.

[0080] [Overview of the prefecture] [Configuration 1] An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results in the first control unit, and a second target value which is the difference between the average reactive power value and the average reactive power offset value. A third control unit determines a voltage control target value from the difference between the first target value and the effective value of the active power of the AC / DC converter, and the difference between the second target value and the effective value of the reactive power of the AC / DC converter. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power of the AC / DC converters by commanding each of the AC / DC converters with the aforementioned voltage control target value. [Configuration 2] An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit that calculates the effective value of active power calculated from the voltage and current for each of the AC / DC converters, and the effective value of reactive power calculated from the voltage and current for each of the AC / DC converters, A second control unit calculates a first target value obtained by weighting the average active power value, which is determined based on the effective active power value, by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the average reactive power value, which is determined based on the effective reactive power value, by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and from the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power of each AC / DC converter by commanding the aforementioned voltage control target value to each AC / DC converter. [Configuration 3] An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value obtained by weighting the difference between the average active power value and the average active power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the difference between the average reactive power value and the average reactive power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power for each of the AC / DC converters by commanding the AC / DC converters with the aforementioned voltage control target value. [Structure 4] The power system described in configuration 3, A standalone centralized control controller that implements the second control unit, Includes a distributed control controller equal to the number of AC / DC converters that implement the first control unit and the third control unit, The centralized control controller and the distributed control controller are each connected to a communication line. Each of the distributed control controllers transmits to the central control controller the difference between the effective value of the active power and the effective power offset value, and the difference between the effective value of the reactive power and the reactive power offset value. The centralized control controller transmits to each of the distributed control controllers a weighted value obtained by weighing the difference between the average active power value and the average active power offset value, and a weighted value obtained by weighing the difference between the average reactive power value and the average reactive power offset value. Each of the AC / DC converter input / output controllers transmits voltage and current for each of the AC / DC converters to the central control controller. A power system characterized in that the centralized control controller transmits the voltage control target value or the current control target value obtained from the voltage control target value to each of the AC / DC converter input / output controllers. [Composition 5] The power system described in configuration 3, The system includes a distributed control controller equal to the number of AC / DC converters that implement the first control unit, the second control unit, and the third control unit, and the distributed control controllers are connected to each other by communication lines. A power system characterized in that each of the distributed control controllers transmits the effective active power value and the effective reactive power value for each of the AC / DC converters to the other distributed control controllers. [Composition 6] The power system described in configuration 3, The system further comprises a fourth control unit that determines a current control target value using a controller that includes an integrator determined from the voltage control target value determined by the third control unit and the voltage of each of the AC / DC converters, A power system characterized by having a control controller that controls the active power and reactive power of each of the AC / DC converters by commanding each of the AC / DC converters with the current control target value. [Composition 7] A control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results in the first control unit, and a second target value which is the difference between the average reactive power value and the average reactive power offset value. A third control unit determines a voltage control target value from the difference between the first target value and the effective value of the active power of the AC / DC converter, and the difference between the second target value and the effective value of the reactive power of the AC / DC converter. Equipped with, A power system control device characterized by controlling the active power and reactive power of the AC / DC converters by commanding each of the AC / DC converters with the aforementioned voltage control target value. [Structure 8] A control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit that calculates the effective value of active power calculated from the voltage and current for each of the AC / DC converters, and the effective value of reactive power calculated from the voltage and current for each of the AC / DC converters, A second control unit calculates a first target value obtained by weighting the average active power value, which is determined based on the effective active power value, by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the average reactive power value, which is determined based on the effective reactive power value, by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and from the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system control device characterized by controlling the active power and reactive power of each AC / DC converter by commanding the aforementioned voltage control target value to each AC / DC converter. [Composition 9] A control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value obtained by weighting the difference between the average active power value and the average active power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the difference between the average reactive power value and the average reactive power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system control device characterized by controlling the active power and reactive power for each of the AC / DC converters by commanding the AC / DC converters with the aforementioned voltage control target value. [Explanation of Symbols]

[0081] 10 (10A~10N) AC / DC converter, 12 (12A~12N) Input / Output controller, 14 (14A~14N) Current controller, 16 Power reference value calculation unit, 16-2p Active power reference value calculation unit, 16-2q Reactive power reference value calculation unit, 18 Control controller, 100 Power system.

Claims

1. An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results in the first control unit, and a second target value which is the difference between the average reactive power value and the average reactive power offset value. A third control unit determines a voltage control target value from the difference between the first target value and the effective value of the active power of the AC / DC converter, and the difference between the second target value and the effective value of the reactive power of the AC / DC converter. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power of the AC / DC converters by commanding each of the AC / DC converters with the aforementioned voltage control target value.

2. An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit that calculates the effective value of active power calculated from the voltage and current for each of the AC / DC converters, and the effective value of reactive power calculated from the voltage and current for each of the AC / DC converters, A second control unit calculates a first target value obtained by weighting the average active power value, which is determined based on the effective active power value, by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the average reactive power value, which is determined based on the effective reactive power value, by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and from the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power of each AC / DC converter by commanding the aforementioned voltage control target value to each AC / DC converter.

3. An AC / DC converter having an AC / DC converter input / output controller, An AC bus in which multiple devices with power supplies capable of input and output are connected in parallel, In a power system having, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value obtained by weighting the difference between the average active power value and the average active power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the difference between the average reactive power value and the average reactive power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system characterized by having a control controller that controls the active power and reactive power for each of the AC / DC converters by commanding the AC / DC converters with the aforementioned voltage control target value.

4. The power system according to claim 3, A standalone centralized control controller that implements the second control unit, Includes a distributed control controller equal to the number of AC / DC converters that implement the first control unit and the third control unit, The centralized control controller and the distributed control controller are each connected to a communication line. Each of the distributed control controllers transmits to the central control controller the difference between the effective value of the active power and the effective power offset value, and the difference between the effective value of the reactive power and the reactive power offset value. The centralized control controller transmits to each of the distributed control controllers a weighted value obtained by weighing the difference between the average active power value and the average active power offset value, and a weighted value obtained by weighing the difference between the average reactive power value and the average reactive power offset value. Each of the AC / DC converter input / output controllers transmits voltage and current for each of the AC / DC converters to the central control controller. A power system characterized in that the centralized control controller transmits the voltage control target value or the current control target value obtained from the voltage control target value to each of the AC / DC converter input / output controllers.

5. The power system according to claim 3, The system includes a distributed control controller equal to the number of AC / DC converters that implement the first control unit, the second control unit, and the third control unit, and the distributed control controllers are connected to each other by communication lines. A power system characterized in that each of the distributed control controllers transmits the effective active power value and the effective reactive power value for each of the AC / DC converters to the other distributed control controllers.

6. The power system according to claim 3, The system further comprises a fourth control unit that determines a current control target value using a controller that includes an integrator determined from the voltage control target value determined by the third control unit and the voltage of each of the AC / DC converters, A power system characterized by having a control controller that controls the active power and reactive power of each of the AC / DC converters by commanding each of the AC / DC converters with the current control target value.

7. In a control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted effective active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value which is the difference between the average active power value and the average active power offset value obtained based on the calculation results in the first control unit, and a second target value which is the difference between the average reactive power value and the average reactive power offset value. A third control unit determines a voltage control target value from the difference between the first target value and the effective value of the active power of the AC / DC converter, and the difference between the second target value and the effective value of the reactive power of the AC / DC converter. Equipped with, A power system control device characterized by controlling the active power and reactive power of the AC / DC converters by commanding the aforementioned voltage control target value to each of the AC / DC converters.

8. In a control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit that calculates the effective value of active power calculated from the voltage and current for each of the AC / DC converters, and the effective value of reactive power calculated from the voltage and current for each of the AC / DC converters, A second control unit calculates a first target value obtained by weighting the average active power value, which is determined based on the effective active power value, by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the average reactive power value, which is determined based on the effective reactive power value, by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and from the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system control device characterized by controlling the active power and reactive power of each AC / DC converter by commanding the aforementioned voltage control target value to each AC / DC converter.

9. In a control device for a power system having an AC / DC converter with an AC / DC converter input / output controller, and an AC bus in which multiple devices having power supplies capable of input and output are connected in parallel, A first control unit calculates the difference between the effective active power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted active power offset value for each of the AC / DC converters, and the difference between the effective reactive power value calculated from the voltage and current for each of the AC / DC converters and an arbitrary weighted reactive power offset value for each of the AC / DC converters. A second control unit calculates a first target value obtained by weighting the difference between the average active power value and the average active power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary active power distribution ratio, and a second target value obtained by weighting the difference between the average reactive power value and the average reactive power offset value obtained based on the calculation results of the first control unit by the number of AC / DC converters and an arbitrary reactive power distribution ratio. A third control unit determines a voltage control target value from the difference between the first target value weighted by the active power distribution ratio and the effective active power value of each of the AC / DC converters, and the difference between the second target value weighted by the reactive power distribution ratio and the effective reactive power value of each of the AC / DC converters. Equipped with, A power system control device characterized by controlling the active power and reactive power for each of the AC / DC converters by commanding the AC / DC converters with the aforementioned voltage control target value.

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