WO2017009921A1

WO2017009921A1 - Power distributor and power distribution method

Info

Publication number: WO2017009921A1
Application number: PCT/JP2015/070002
Authority: WO
Inventors: 重雄大前; 直樹丸
Original assignee: 株式会社日立製作所
Priority date: 2015-07-13
Filing date: 2015-07-13
Publication date: 2017-01-19

Abstract

The present invention minimizes any imbalance in a three-phase current while preventing a loss of power. In the present invention, a power distributor is provided with: a plurality of switching devices that are connected to a three-phase AC power supply and are connected in a respective manner to a plurality of electronic devices; and a control device for acquiring electrical current information that indicates the magnitude of electrical current measured at a plurality of sites, selecting two of three phases on the basis of the electrical current information, and issuing an instruction to the switching devices to output the selected two phases. The switching devices output single-phase alternating current to a corresponding electronic device by outputting the two instructed phases of the three phases.

Description

Power distributor and power distribution method

The present invention relates to a power distributor.

In general, facilities that use large-scale power, such as factories and data centers, transmit power from power companies using three-phase AC with less power loss than single-phase AC. In factories and data centers, for electronic devices that operate with single-phase AC, power is distributed from three-phase AC to single-phase AC using a power distribution facility such as a distribution board.

In the world, there are many electronic devices that operate with three-phase alternating current, but in Japan electronic devices that operate with single-phase alternating current are common. In recent years, the number of products that support three-phase alternating current has increased in electronic computers such as servers due to power saving and increased power consumption due to improved performance. However, most computers are operated by single-phase alternating current. In addition, products that operate with single-phase alternating current are also common in network devices and storage devices.

When a plurality of electronic devices that operate with single-phase AC power supply and have different loads are connected to a three-phase AC power supply facility, the current balance of each phase of the power supply facility becomes unbalanced. If the current balance is in an unbalanced state, the current in one phase will increase, and overcurrent will be easily detected by the protection mechanism, and loss in the phase with a large current will increase. Become.

As a technique to balance the unbalanced state of the current of each phase of the three-phase AC power supply so that the current of each phase of the three-phase AC power supply is in a balanced state when the three-phase AC power supply is in an unbalanced state A method of connecting an appropriate dummy resistor between each phase (Patent Document 1) has been proposed. Also, a method of connecting a three-phase input single-phase output conversion device composed of a rectifier circuit and a single-phase inverter circuit between a three-phase AC power supply facility and an electronic device that operates by single-phase AC power supply (Patent Document 2) ) Has been proposed.

JP 2009-301742 A JP 2011-015569 A

If the current in only one of the three phases becomes large due to the above-mentioned unbalanced state, overcurrent may be detected by the protection mechanism on the equipment side, so the power equipment capacity cannot be used effectively. In addition, when the current of only a certain phase increases, the loss in that phase increases, so that the phase voltage drop increases and may lead to malfunction of the electronic device.

In the method of Patent Document 1, since power is consumed by a dummy load in order to achieve an equilibrium state, there is a problem that power is wasted. In the method of Patent Document 2, conversion from a three-phase alternating current to a direct current and conversion from a direct current to a single-phase alternating current are performed in a three-phase input single-phase output conversion device. There is a problem that loss occurs.

In order to solve the above problems, a power divider according to one aspect of the present invention is measured at a plurality of switching devices connected to a three-phase AC power source and connected to a plurality of electronic devices, and a plurality of locations. A control device that obtains current information indicating a magnitude of current, selects two phases of the three phases based on the current information, and instructs the output of the selected two phases for each switching device; Prepare. Each switching device outputs a single-phase alternating current to the corresponding electronic device by outputting the designated two phases of the three phases.

三 Three-phase current imbalance can be suppressed while preventing power loss.

The structure of the power divider | distributor of embodiment of this invention is shown. The structure of the phase switching part 3n of a 1st modification is shown. The structure of the phase switching part 3n of a 2nd modification is shown. The direction of the current flowing in the load between each phase is shown. The time change of the voltage between each phase is shown. The current value comparison process is shown. The phase switching control process is shown. The specific example of a phase switching control process is shown.

In the following description, information may be described using the expression “xxx table”, but the information may be expressed in any data structure. That is, “xxx table” can be referred to as “xxx information” to indicate that the information does not depend on the data structure. In the following description, the configuration of each table is an example, and one table may be divided into two or more tables, or all or part of the two or more tables may be a single table. Good.

In the following description, an ID is used as element identification information, but other types of identification information may be used instead of or in addition thereto.

In the following description, when a description is made without distinguishing the same type of element, a reference number or a common number in the reference number is used, and when a description is made by distinguishing the same type of element, the reference number of the element is used. Alternatively, an ID assigned to the element may be used instead of the reference code.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a power distributor according to an embodiment of the present invention.

The power distributor 100 receives a three-phase AC power supply and outputs a plurality of single-phase AC power supplies. The power distributor 100 includes a three-phase AC power receiving unit 1 (three-phase input terminal), three-

phase AC ammeters

21, 22, and 23 (current measuring unit), and n (n is a positive integer) phase switching unit. 31 to 3n, n single-phase AC output units 61 to 6n (output terminals, single-phase output terminals), and a control unit 7 (control device). Phase switching units 31 to 3n (switching devices) include switching units 411 to 4n1, respectively, include switching units 412 to 4n2, and include switching control units 51 to 5n. The switches 411 to 4n1 include switching switches SW111A to SWn11A, respectively, include switching switches SW112A to SWn12A, and include switching switches SW113A to SWn13A. The switches 412 to 4n2 include changeover switches SW121A to SWn21A, respectively, SW122A to SWn22A, and SW123A to SWn23A.

Note that the power distributor 100 according to the present embodiment may not include the external signal input terminal 9 and the electronic device information SIG81 to SIG8n.

The power distributor 100 receives the three-phase AC power from the three-phase AC power receiving unit 1. The three-phase AC power source passes through three-

phase AC ammeters

21, 22, and 23. The three-phase AC power source that has passed through the three-

phase AC ammeters

21, 22, and 23 is switched to a single-phase AC power source by the phase switching units 31 to 3n. The phase switching units 31 to 3n output the two phases L11 and L12, L21 and L22,..., Ln1 and Ln2 in the three-phase AC power source to the single-phase AC output units 61 to 6n, respectively. The single-phase AC output units 61 to 6n supply single-phase AC power to the electronic devices 81 to 8n connected thereto.

Each of the three-

phase AC ammeters

21, 22, and 23 is an ammeter, for example, and converts the effective value of the AC current of the corresponding phase into a DC voltage. The three-

phase AC ammeters

21, 22, and 23 output phase current information SIG21, SIG22, and SIG23, respectively, indicating phase current values based on the DC voltage at preset measurement time intervals. The phase current information may be an I2C signal.

Each of the change-over switches SW111A to SWn11A, SW112A to SWn12A, SW113A to SWn13A, SW121A to SWn21A, SW122A to SWn22A, SW123A to SWn23A has a terminal for receiving a switch signal indicating a high or low level from the outside. This is a switch element having a function of switching contacts according to the level.

JEITA IT-1004A Industrial information processing / control equipment installation environment standard describes the instantaneous power failure time that guarantees the quality of the power supply for electronic devices against instantaneous power failure. The instantaneous power failure time of Class A having the shortest instantaneous power failure time is 3 mS or less. That is, the operation quality of the Class A electronic device must be guaranteed in an instantaneous power failure of 3 mS. The switching time of a switch having a general control terminal is on the order of several nS to several μS for a transistor-based switch, and is about several tens of μS even for a switch product sold for a load line. Since these switching times are sufficiently shorter than the above-described instantaneous power failure time, the operation quality of the electronic device is not impaired by switching the contacts of the switching switch.

The switching control units 51 to 5n receive the phase switching instruction signals SIG31 to SIG3n (control signals) from the control unit 7, respectively. Each of the phase switching instruction signals SIG31 to SIG3n is, for example, an I2C signal. Each of the switching control units 51 to 5n outputs a switching signal indicating a high or low level to each switching switch. The switching control units 51 to 5n are, for example, integrated circuits such as I / O Expander and FPGA.

The control unit 7 acquires the phase current values Ir [t], Is [t], and It [t] of the R phase, the S phase, and the T phase indicated in the phase current information SIG21, SIG22, and SIG23 at time t, respectively. Remember. The control unit 7 determines the stored three phase current values in order from the largest value as the maximum phase current value MaxI [t], the intermediate phase current value MidI [t], and the minimum phase current value MinI [t]. The current difference DeltaI [t] between the maximum phase current value MaxI [t] and the minimum phase current value MinI [t] is calculated, the magnitude relationship between the phase current values, and the current difference between the maximum phase current value and the minimum phase current value Then, two phases to be output from each of the phase switching units 31 to 3n are selected. The control unit 7 outputs phase switching instruction signals SIG31 to SIG3n such as I2C signals to the switching control units 51 to 5n, respectively. The control unit 7 includes, for example, an integrated circuit such as an FPGA or an embedded microprocessor, and a memory.

The switching control units 51 to 5n are connected to the switching switches SW111A to SWn11A, SW112A to SWn12A, SW113A to SWn13A, and SW113A to SWn13A, SW113A to SnnA, S112A to Sn12A, S113A to Sn13A, S121A to Sn21A, By switching ON / OFF of SWn21A, SW122A to SWn22A, SW123A to SWn23A, the output of each of the switches 411 to 4n1, 412 to 4n2 is set to any one of R phase, S phase, and T phase. Is possible.

FIG. 2 shows a configuration of the phase switching unit 3n according to the first modification.

In the phase switching unit 3n of the first modification, the switches 4n1 and 4n2 include contact switching switches SWn11B and SWn21B that output any one of the R phase and the S phase, respectively. The switches 4n1 and 4n2 further include contact switching switches SWn12B and SWn22B that output one of the outputs of the contact switching switches SWn11B and SWn21B and the T phase, respectively.

The switching control unit 5n switches the contacts of the contact selector switches SWn11B, SWn12B, SWn21B, and SWn22B according to the switching signals Sn11B, Sn12B, Sn21B, and Sn22B, respectively, and outputs the outputs of the switches 4n1 and 4n2 to the R phase and Sn, respectively. It can be set to either one of the phase and the T phase.

According to the first modification, the number of parts and the number of signals can be reduced as compared with the phase switching unit 3n in FIG.

FIG. 3 shows the configuration of the phase switching unit 3n of the second modification.

In the phase switching unit 3n of the second modification, the switch 4n1 includes a contact switch SWn11C that outputs any one of the R phase and the S phase. The switch 4n2 includes a contact switch SWn21C that outputs one of the S phase and the T phase. The switching control unit 5n can set the output of the switch 4n1 to one of the R phase and the S phase by switching the contacts of the SWn11C and SWn21C respectively by the switching signals Sn11C and Sn21C, and the output of the switch 4n2 Can be set to one of the S phase and the T phase.

According to the second modification, the number of parts and the number of signals can be reduced as compared with the phase switching unit 3n in FIG.

According to each phase switching unit 3n described above, the two phases indicated in the phase switching instruction signal from the control unit 7 among the three phases input from the three-phase AC power receiving unit 1 are converted into corresponding single-phase AC outputs. Can be output to the unit 6n.

FIG. 4 shows the direction of the current flowing through the load between the phases.

Z1 is a load to which a voltage is applied between the R phase and the S phase. Z2 is a load to which a voltage is applied between the S phase and the T phase. Z3 is a load to which a voltage is applied between the T phase and the R phase or between the R phase and the T phase. In a general three-phase AC delta connection, a voltage is applied to Z3 between the T phase and the R phase. In Example 1 and the first modification, the load current flowing through Z1 is represented by a load current value I1 from the R phase toward the S phase, and the load current flowing through Z2 is the load current value I2 from the S phase toward the T phase. The load current flowing through Z3 is represented by a load current value I3 from the T phase to the R phase. In the second modification, the output of the switch 4n1 can be set to any one of the R phase and the S phase, and the output of the switch 4n2 can be set to any one of the S phase and the T phase. As a result, since a voltage is applied to Z3 between the R phase and the T phase, the load current flowing through Z3 is represented by a load current value I3 'from the R phase to the T phase. In the first embodiment and the first modification, the current flowing through Z3 may be represented by either I3 or I3 '.

FIG. 5 shows the time change of the voltage between the phases.

The R phase-S phase voltage, the S phase-T phase voltage, and the T phase-R phase voltage are out of phase by 120 °. In the first embodiment and the first modified example, the control unit 7 calculates the R-phase current vector, the S-phase current vector, and the T-phase current vector according to the equations (1), (2), and (3), respectively. calculate. Further, the control unit 7 calculates phase current values Ir, Is, It, which are absolute values of the R-phase, S-phase, and T-phase current vectors, using the equations (7), (8), and (9), respectively. . In the second modification, the control unit 7 calculates the R-phase, S-phase, and T-phase current vectors using Equation (4), Equation (5), and Equation (6), respectively.

FIG. 6 shows a current value comparison process.

In the current value comparison process, the control unit 7 sets the phase current values Ir [t], Is [t], and It [t] at time t in descending order of the maximum phase current value MaxI [t] and the intermediate phase current value MidI [ t] and the minimum phase current value MinI [t].

The control unit 7 first compares the magnitudes of the phase current value Ir [t] of the R phase and the phase current value Is [t] of the S phase (S110), and the larger one is obtained as a result of the first magnitude comparison. The phase current value It [t] of the T phase is compared (S120 or S320). Then, the control unit 7 determines the larger phase current value as the maximum phase current value MaxI [t] as a result of the second magnitude comparison (S130, S230, S330, or S430). When the intermediate phase current value MidI [t] and the minimum phase current value MinI [t] are determined based on the result of the first magnitude comparison and the result of the second magnitude comparison, the control unit 7 determines the intermediate phase current value MidI. [T] and the minimum phase current value MinI [t] are determined (S250 or S450). On the other hand, when the intermediate phase current value MidI [t] and the minimum phase current value MinI [t] are not determined, the control unit 7 compares two phase current values other than the maximum phase current value MaxI [t] (S140 or In step S340, the intermediate phase current value MidI [t] and the minimum phase current value MinI [t] are determined based on the comparison result (S150, S160, S350, or S360).

Through the above current value comparison processing, the phase current values Ir [t], Is [t], It [t] are changed from the largest phase current value to the maximum phase current value MaxI [t] and the intermediate phase current value MidI [t. ], The minimum phase current value MinI [t]. The phase corresponding to the maximum phase current value is the first phase (maximum phase), the phase corresponding to the intermediate phase current value is the second phase (intermediate phase), and the phase corresponding to the minimum phase current value is the third phase (minimum phase). Phase).

FIG. 7 shows the phase switching control process.

Here, the case where n = 6 will be described.

The voltage of each output of the phase switching units 31 to 36 is any one of the R phase-S phase voltage, the S phase-T phase voltage, and the T phase-R phase voltage. The control unit 7 changes the state of the phase switching units 31 to 36 by sending a phase switching instruction signal for setting the switch to the switching control unit of each phase switching unit. The control unit 7 stores output state values (state values) indicating the output states of the phase switching units 31 to 36 at time t as arrays O61C [t] to O66C [t], respectively. The output state value is represented as RS between R phase and S phase, ST between S phase and T phase, and TR between T phase and R phase. For example, when the output of the phase switching unit 31 is set between the R phase and the S phase, the output state value O61C [t] = RS is set.

The control unit 7 stores the switching priorities of the phase switching units 31 to 36 at time t as arrays O61P [t] to O66P [t]. The switching priority is set as a numerical value from 1 to n. The control unit 7 selects the phase switching unit in which 1 which is the smallest numerical value is set, and changes the phase switching instruction signal of the selected phase switching unit. Further, the maximum switching priority that is the maximum value of the RS switching priority is a variable X, the maximum switching priority of ST is a variable Y, and the maximum switching priority of TR is a variable Z.

For example, the output state values of the

phase switching units

31, 32, and 33 are O61C [t] = RS, O62C [t] = RS, O63C [t] = RS, and the switching priority of the

phase switching units

31, 32, and 33 Are O61P [t] = 2, O62P [t] = 1, and O63P [t] = 3, the control unit 7 selects the phase switching unit 32 corresponding to O62P [t] which is the minimum value thereof. The phase switching instruction signal of the phase switching unit 32 is changed, and the output state value O62C [t] of the phase switching unit 32 is changed according to the phase switching instruction signal. In this case, the maximum switching priority order X corresponding to RS is 3.

In FIG. 7, as an initial setting (S510), the control unit 7 sets the phase switching instruction signals of the

phase switching units

31 and 34 to the R phase and the S phase, and accordingly the output state values of the

phase switching units

31 and 34 RS is stored, phase switching instruction signals of the

phase switching units

32 and 35 are set to S phase and T phase, and ST is stored in the output state values of the

phase switching units

32 and 35 accordingly, and the

phase switching unit

33 , 36 are set to the T phase and the R phase, and TR is stored in the output state values of the

phase switching units

33, 36 accordingly. Further, the control unit 7 sets the switching priority of the

phase switching units

31, 32, and 33 to 1, sets the switching priority of the

phase switching units

34, 35, and 36 to 2, sets the maximum switching priority X of the RS to 2, ST Is set to 2 and the maximum switching priority Z of TR is set to 2. Here, the control unit 7 sets the initial value of each maximum switching priority as n / 3 phase = 6/3 = 2. Further, the control unit 7 sets a current threshold Ith (evaluation threshold) indicating a target current difference to 3A.

Next, the control unit 7 acquires the effective value of the current and executes a current value comparison process (S520). Here, the control unit 7 receives the phase current values of the three-

phase AC ammeters

21, 22, and 23 at time t and stores the respective phase current values in the arrays Ir [t], Is [t], and It [t]. To do. Next, the control unit 7 determines the maximum phase current value MaxI [t], the intermediate phase current value MidI [t], and the minimum phase current value MinI [t] by the above-described current value comparison processing.

Next, the control unit 7 calculates the current difference DeltaI [t] (evaluation value) by subtracting the minimum phase current value MinI [t] from the maximum phase current value MaxI [t] (S530).

Next, the control unit 7 compares the current difference DeltaI [t] with the current threshold value Ith (S540). When the current difference DeltaI [t] is less than the current threshold Ith (S540: YES), the control unit 7 determines that the R phase, the S phase, and the T phase are in an equilibrium state, and the phase switching units 31 to 3n Without changing the phase switching instruction signal, 1 is added to t as shown in Equation (10) (S550), and after the measurement time interval elapses from the acquisition of the phase current value, the three-

phase AC ammeters

21, 22, 23 The process returns to the operation of acquiring the phase current value (S520). When the current difference DeltaI [t] is equal to or greater than the current threshold Ith (S540: NO), the control unit 7 determines that the state is unbalanced, selects one phase switching unit, and changes the phase switching instruction signal. To do.

T = t + 1 (10)

The current difference DeltaI [t] is equal to or greater than the current threshold Ith (S540: NO), the maximum phase current value is the R-phase phase current value (MaxI [t] = Ir [t]) (S610: YES), and the minimum When the phase current value is the phase current value of the S phase (MinI [t] = Is [t]) (S620: YES), the control unit 7 determines the phase of the maximum phase current value MaxI [t] and the intermediate phase current value MidI. TR representing between the phases of [t] is selected as a change source state, and ST representing between the phase of the intermediate phase current value MidI [t] and the phase of the minimum phase current value MinI [t] is changed. Select as the destination state. The control unit 7 selects a phase switching unit whose output state value is the change source state TR and whose switching priority is set to 1 as a changed phase switching unit (specific switching device). Here, the control unit 7 selects the phase switching unit 33 having the output state value O63C [t] = TR and the switching priority O63P [t] = 1 as the changed phase switching unit. Next, the control unit 7 changes the phase switching instruction signal of the changed phase switching unit to the change destination state. That is, the control unit 7 sets the phase switching instruction signal TR of the phase switching unit 33 to ST (S700). Thereafter, the control unit 7 adds 1 to the time t as shown in Expression (10) (S710). Thereafter, the control unit 7 sets the output state value in the phase switching unit 33 to O63C [t] = ST in accordance with the change destination state, and changes to the switching priority order of the phase switching unit 33 according to the equation (11). By adding the maximum switching priority Y corresponding to the previous state ST, O63P [t] = 3 is set (S720).

O63P [t] = Y + 1 = 2 + 1 = 3 (11)

Thereafter, the control unit 7 selects a phase switching unit other than the changed phase switching unit as the maintenance phase switching unit in the phase switching unit having the change source state, and decreases the switching priority of the maintenance phase switching unit. That is, the control unit 7 selects the phase switching unit 36 whose output state value is TR and is a phase switching unit other than the phase switching unit 33 as a maintenance phase switching unit. By subtracting 1 from the switching priority, O66P [t] = 1 is set (S730).

O66P [t] = O66P [t-1] -1 = 2-1 = 1 (12)

Next, the control unit 7 adds 1 to the maximum switching priority Y corresponding to the change destination state ST by the equation (13), and 1 from the maximum switching priority Z corresponding to the change source state TR by the equation (14). Is reduced (S740). Thereafter, the control unit 7 returns to the operation (S520) of acquiring the phase current values of the three-

phase AC ammeters

21, 22, and 23 after the measurement time interval has elapsed since the acquisition of the phase current values.

Y = Y + 1 = 2 + 1 = 3 (13)
Z = Z-1 = 2-1 = 1 (14)

When the maximum phase current value is the phase current value of the R phase (S610: YES) and the minimum phase current value is the phase current value of the S phase (S620: NO), the control unit 7 changes in the same manner as S700 to S740. A process (S750 to S790) in which the original state is RS and the change destination state is ST is executed, and after the measurement time interval elapses from the acquisition of the phase current value, the process returns to S520.

When the maximum phase current value is the phase current value of the S phase (S610: NO, S630: YES) and the minimum phase current value is the phase current value of the T phase (S640: YES), the control unit 7 is the same as S700 to S740. Then, the process (S800 to S840) is executed in which the change source state is RS and the change destination state is TR (S800 to S840), and after the measurement time interval elapses from the acquisition of the phase current value, the process returns to S520.

When the maximum phase current value is the phase current value of the S phase (S610: NO, S630: YES) and the minimum phase current value is the phase current value of the R phase (S640: NO), the control unit 7 is the same as S700 to S740. Then, the process (S850 to S890) is executed in which the change source state is ST and the change destination state is TR (S850 to S890), and after the measurement time interval elapses from the acquisition of the phase current value, the process returns to S520.

When the maximum phase current value is the phase current value of the T phase (S610: NO, S630: NO), and the minimum phase current value is the phase current value of the R phase (S640: YES), the control unit 7 is the same as S700 to S740. Then, a process (S900 to S940) is executed in which the change source state is ST and the change destination state is RS (S900 to S940), and after the measurement time interval elapses from the acquisition of the phase current value, the process returns to S520.

When the maximum phase current value is the phase current value of the T phase (S610: NO, S630: NO), and the minimum phase current value is the phase current value of the S phase (S640: NO), the control unit 7 is the same as S700 to S740. Then, a process (S950 to S990) is executed in which the change source state is TR and the change destination state is RS (S950 to S990), and after the measurement time interval elapses from the acquisition of the phase current value, the process returns to S520.

According to the above phase switching control processing, the control unit 7 calculates the evaluation value indicating the magnitude of the unbalance of the three-phase current, and changes the phase switching on the condition that the magnitude of the unbalance is reduced. By selecting the part and the change destination state, the current unbalance rate can be reduced. When the control unit 7 periodically acquires phase current information, determines whether the evaluation value satisfies a preset unbalance condition, and determines that the evaluation value satisfies the unbalance condition In addition, the current unbalance rate can be reduced by selecting the changed phase switching unit from among the plurality of phase switching units. Moreover, the control part 7 can adapt the state of a phase switching part even when the load current of an electronic device fluctuates, and can prevent an unbalanced state. In addition, the control unit 7 can maintain the state of the phase switching unit when the evaluation value does not satisfy the unbalanced condition.

Further, the control unit 7 can evaluate the magnitude of the unbalance of the three-phase current by setting the current difference obtained by subtracting the minimum phase current value from the maximum phase current value as an evaluation value. Further, when the current difference exceeds the current threshold, the control unit 7 can recognize the unbalanced state by selecting the changed phase switching unit and controlling the changed phase switching unit. Moreover, the control part 7 selects the state which outputs a 1st phase and a 2nd phase as a change origin state, selects the state which outputs a 2nd phase and a 3rd phase as a change destination state, and changes a change origin state By switching the phase switching unit to the change destination state, the current unbalance rate can be reduced.

Also, the control unit 7 selects the phase switching unit having the highest switching priority from the phase switching unit group in the change source state as the changed phase switching unit, and decreases the switching priority of the changed phase switching unit. Thereby, the control part 7 can select an appropriate change phase switching part, even when a some phase switching part is a change origin state. Moreover, the control part 7 can prevent that two states are repeated alternately because the same phase switching part is continuously selected as a change phase switching part.

Note that priority may be used instead of switching priority. For example, the control unit 7 selects the phase switching unit having the highest priority from the phase switching unit group in the change source state as the changed phase switching unit, and decreases the priority of the changed phase switching unit.

FIG. 8 shows a specific example of the phase switching control process.

The effective value of the load current flowing through the electronic device is called the load current value. Here, n = 6, the load current value of the electronic device 81 is 25 A, the load current value of the electronic device 82 is 8 A, the load current value of the electronic device 83 is 11 A, the load current value of the electronic device 84 is 15 A, the electronic The state transition when the load current value of the device 85 is 5A, the load current value of the electronic device 86 is 10A, and the current threshold Ith is 3A is shown.

This figure shows the state at time t for each measurement time interval. Each state includes a load current flowing through each of the electronic devices 81 to 86, a state of the phase switching units 31 to 36 output to the electronic device (phase switching unit state), and phase current values Ir [t] and Is [t]. , It [t] (MaxI [t], MidI [t], MinI [t] in descending order) and current difference determination results.

At time t = 0, the current difference DeltaI [0] = 23.96A is larger than the current threshold Ith = 3A, and the maximum phase current value MaxI [0] is the R-phase phase current value Ir [0]. Since the minimum phase current value MinI [0] is the T-phase phase current value It [0], the control unit 7 outputs two values in the phase switching unit 31 whose output state value is RS and whose switching priority is 1. The switch is switched to the S phase and the T phase, respectively. As a result, the control unit 7 sets the output state value O61C [1] of the phase switching unit 31 to ST and sets the switching priority O61P [1] to 3 at time t = 1. Further, the control unit 7 sets the switching priority O64P [t] of the phase switching unit 34 other than the phase switching unit 31 among the phase switching units whose output state value is RS at time t = 0 to 1.

At time t = 1, the current difference Delta [1] = 2.48A is larger than the current threshold Ith = 3A, and the maximum phase current value MaxI [1] is the T-phase phase current value It [1]. Since the minimum phase current value MinI [1] is the R-phase phase current value Ir [1], the control unit 7 has two output states in the phase switching unit 32 in which the output state value is ST and the switching priority is 1. The switch is switched to the R phase and the S phase, respectively. Thereby, the control unit 7 sets the output state value O62C [2] of the phase switching unit 32 to RS and sets the switching priority order O62P [2] to 2 at time t = 2. Further, the control unit 7 sets the switching priority O61P [2] to 2 for the

phase switching units

31 and 35 other than the phase switching unit 32 among the phase switching units whose output state value is ST at time t = 1. And set the switching priority O65P [2] to 1.

At time t = 2, the current difference Delta [2] = 7.91A is larger than the current threshold Ith = 3A, and the maximum phase current value MaxI [2] is the S-phase phase current value Is [2]. Since the minimum phase current value MinI [2] is the R-phase phase current value Ir [2], the control unit 7 has two output states in the phase switching unit 35 whose output state value is ST and whose switching priority is 1. The switch is switched to the T phase and the R phase, respectively. As a result, the control unit 7 sets the output state value O65C [3] of the phase switching unit 35 to TR and sets the switching priority O65P [3] to 3 at time t = 3. Further, the control unit 7 sets the switching priority O61P [3] of the phase switching unit 31 other than the phase switching unit 35 among the phase switching units whose output state value is ST at time t = 2 to 1.

Since the current difference Delta [3] = 2.59A is smaller than the current threshold Ith = 3A at time t = 3, the output state values of the phase switching units 31 to 36 from time t = 3 to time t = 4. There is no change in the switching priority.

Since the current difference Delta [3] = 2.59A is smaller than the current threshold Ith = 3A at time t = 4, the output state values of the phase switching units 31 to 36 from time t = 4 to time t = 5. There is no change in the switching priority.

Assume that the load current value of the electronic device 81 changes from 25 A to 5 A at time t = 5. Thus, the current difference DeltaI [5] = 16.60A is larger than the current threshold Ith = 3A, the maximum phase current value MaxI [5] is the R-phase phase current value Ir [5], and the minimum phase current Since the value MinI [5] is the phase current value Is [5] of the S phase, the control unit 7 sets the two switches in the phase switching unit 33 whose output state value is TR and the switching priority is 1 to S Switch to phase and T phase, respectively. As a result, the control unit 7 sets the output state value O63C [6] of the phase switching unit 33 to ST and sets the switching priority O63P [6] to 2 at time t = 6. Further, the control unit 7 sets the switching priority O65P [6] to 2 for the

phase switching units

35 and 36 other than the phase switching unit 33 among the phase switching units whose output state value is TR at time t = 5. And set the switching priority O66P [6] to 1.

At time t = 6, the current difference DeltaI [6] = 7.10A is larger than the current threshold Ith = 3A, and the maximum phase current value MaxI [6] is the S-phase phase current value Is [6]. Since the minimum phase current value MinI [6] is the T-phase phase current value It [6], the control unit 7 outputs two values in the phase switching unit 34 whose output state value is RS and whose switching priority is 1. The switch is switched to the T phase and the R phase, respectively.

Thereafter, the control unit 7 changes the output state values of the phase switching units 31 to 36 so that the current difference DeltaI [t] becomes smaller than the current threshold value Ith.

According to the present embodiment, the power distributor 100 measures the input three-phase current, and controls the phase switching unit based on the measured current, thereby suppressing the three-phase current imbalance. be able to. Thereby, overcurrent of one phase can be prevented while suppressing power consumption.

Compared to the first embodiment, each of the electronic devices 81 to 8n of the present embodiment measures the direct current converted from the single-phase alternating current power source to the direct current power source in the electronic device, and based on the measured direct current value. Load current information indicating the effective value of the load current is generated. Furthermore, each of the electronic devices 81 to 8n stores connection information indicating which of the single-phase AC output units 61 to 6n of the power distributor 100 is connected to the electronic device. The connection information includes, for example, electronic device identification information that identifies an electronic device, and terminal identification information that identifies a single-phase AC output unit connected to the electronic device. Further, each of the electronic devices 81 to 8n outputs electronic device information SIG81 to SIG8n including load current information and connection information to the power distributor 100. The electronic device information SIG81 to SIG8n is, for example, an I2C signal.

Note that the power distributor 100 of the present embodiment may not include the three-

phase AC ammeters

21, 22, and 23 and the phase current information SIG21, SIG22, and SIG23.

The electronic device information SIG81 to SIG8n is input to the control unit 7 through the external signal input terminal 9.

The control unit 7 is connected to the load current information, the electronic device corresponding to the electronic device identification information, the single-phase AC output unit corresponding to the terminal identification information, and the single-phase AC output unit based on the electronic device information. And the output state value of the phase switching unit. Further, based on this association and the load current information, the control unit 7 loads the load current value I1 of the voltage between the R phase and the S phase, the load current value I2 of the voltage between the S phase and the T phase, and the voltage between the T phase and the R phase voltage. A load current value I3 is calculated. When n = 6, the load current value of the electronic device 81 is I81, the load current value of the electronic device 82 is I82, the load current value of the electronic device 83 is I83, the load current value of the electronic device 84 is I84, and the electronic device 85 Is assumed to be I85, and the load current value of the electronic device 86 is assumed to be I86.

Control is performed in a state where the

electronic devices

81 and 84 are connected between the R phase and the S phase, the

electronic devices

82 and 85 are connected between the S phase and the T phase, and the

electronic devices

83 and 86 are connected between the T phase and the R phase. The unit 7 calculates the load current values I1, I2, and I3 by the equations (15), (16), and (17), respectively.

I1 = I81 + I84 (15)
I2 = I82 + I85 (16)
I3 = I83 + I86 (17)

The control unit 7 uses the load current values I1, I2, and I3, and the expressions (1), (2), (3), (7), (8), and (9). The phase current value Ir of the R phase, the phase current value Is of the S phase, and the phase current value It of the T phase are calculated. Thus, the control part 7 can calculate a three-phase phase current value by receiving load current information and connection information from an electronic device.

The control unit 7 uses the phase switching unit control process similar to that in the first embodiment using the phase current value Ir of the R phase, the phase current value Is of the S phase, and the phase current value It of the T phase at the time t. The maximum phase current value MaxI [t], the intermediate phase current value MidI [t], and the minimum phase current value MinI [t] are determined, and the current difference DeltaI [t] is calculated and compared with the current threshold Ith. Thus, the equilibrium state of the R phase, the S phase, and the T phase is determined. If it is determined that the state is an unbalanced state, the output state values and switching priority of the phase switching units 31 to 36 are changed.

The control unit 7 may store the connection information by inputting the connection information to the control unit 7 in advance. In this case, the electronic device information does not include connection information.

In addition, the electronic device may measure load information indicating the magnitude of the load on the electronic device instead of the load current value. The load information is, for example, a CPU usage rate or a memory usage rate in the electronic device. For example, when n electronic devices are of the same type, the control unit 7 may estimate the load current value from the load information.

According to the present embodiment, the power distributor 100 acquires the load current value measured by the electronic devices 81 to 8n without measuring the input three-phase AC phase current value, and sets the load current value as the load current value. By calculating the phase current value based on this, the phase switching unit can be controlled as in the first embodiment.

In addition, the control part 7 may call phase current information, load current information, etc. as current information. The control unit 7 can detect an unbalanced state of three-phase currents by acquiring current information indicating the magnitudes of currents measured at a plurality of locations in this way. Based on the current information, the control unit 7 outputs a control signal indicating two of the three phases to each phase switching unit.

The present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the scope of the invention. For example, in each embodiment, the single-phase AC output voltage is the R-phase to S-phase voltage, the S-phase to T-phase voltage, and the T-phase to R-phase voltage, but is not limited thereto.

In each embodiment, the control unit 7 uses the current difference DeltaI [t] as the evaluation value in S530, but is not limited thereto. For example, the control unit 7 calculates a normal phase current and a reverse phase current from Ir, Is, It, calculates a current unbalance rate as an evaluation value from the positive phase current and the reverse phase current, and sets the current unbalance rate in advance. It may be the unbalanced condition that the current unbalance rate is equal to or greater than the threshold value.

According to each embodiment described above, the control unit 7 acquires phase current information, load current information, and the like as current information, and outputs a phase switching instruction signal for each phase switching unit based on the current information. In this way, the control unit 7 controls the phase switching unit based on currents measured at a plurality of locations such as a three-phase current and a plurality of electronic devices, thereby suppressing a three-phase current imbalance. Can do. Moreover, power loss can be prevented by using a plurality of switches without using a dummy load, an AC / DC power converter, a DC / AC power converter, or the like. In addition, even when multiple single-phase loads are connected to a three-phase power supply facility without considering current balance, the three-phase current imbalance can be reduced, and only a specific phase has a large current. It is possible to prevent the occurrence of abnormalities such as overcurrent and to effectively use the power equipment capacity.

DESCRIPTION OF SYMBOLS 1 ... Three-phase alternating current

power receiving part

21, 22, 23 ... Three-phase alternating current ammeter, 3n ... Phase switching part, 4n1, 4n2 ... Switching part, 5n ... Switching control part, 6n ... Single phase alternating current output part, 7 ... Control 8n ... electronic equipment, 9 ... external signal input terminal, 100 ... power distributor, SWn11A, SWn12A, SWn13A, SWn21A, SWn22A, SWn23A, SWn11B, SWn12B, SWn21B, SWn22B, SWn11C, SWn21C ...

Claims

A plurality of switching devices connected to a three-phase AC power source and respectively connected to a plurality of electronic devices;
Current information indicating the magnitude of the current measured at a plurality of locations is obtained, and for each switching device, two phases of the three phases are selected based on the current information, and the selected two-phase output is obtained. A control device to direct;
With
Each switching device outputs a single-phase alternating current to the corresponding electronic device by outputting the indicated two phases of the three phases.
A power distributor comprising:
The control device calculates an evaluation value indicating the magnitude of the unbalance of the three-phase current based on the current information,
The control device selects a specific switching device from the plurality of switching devices on condition that the magnitude of the unbalance is reduced, changes two phases output to the specific switching device, and changes the change Directing the specified two-phase output to the specific switching device,
The power distributor according to claim 1.
The control device periodically acquires the current information, calculates the evaluation value based on the current information, determines whether the evaluation value satisfies a preset unbalance condition, When it is determined that the evaluation value satisfies the unbalanced condition, the specific switching device is selected and the specific switching device is controlled.
The power distributor according to claim 2.
The control device acquires the current value of the three phases based on the current information, and selects the first phase, the second phase, and the third phase from the three phases in descending order of the current value, The evaluation value is calculated by subtracting the current value of the third phase from the current value of the first phase, whether or not the evaluation value exceeds a preset evaluation threshold value, and the evaluation value is If it is determined that the evaluation threshold is exceeded, the evaluation value is determined to satisfy an unbalanced condition;
The power distributor according to claim 3.
When it is determined that the evaluation value satisfies the unbalanced condition, the control device selects the specific switching device that outputs the first phase and the second phase from the plurality of switching devices, Instructing the specific switching device to output the second phase and the third phase;
The power distributor according to claim 4.
The control device stores a state value indicating two phases output to each switching device, and a priority of selection of each switching device,
The control device selects a switching device group that outputs the first phase and the second phase from the plurality of switching devices based on a state value of each switching device, and selects the switching device group from the switching device group Selecting the switching device corresponding to the highest priority as the specific switching device, and lowering the priority of the specific switching device;
The power distributor according to claim 5.
Each switching device includes two or more switches that connect the indicated two phases of the three phases to a corresponding electronic device.
The power distributor according to claim 1.
Further comprising a current measurement unit that measures the current values of the three phases each indicating the magnitude of the current of the three phases, and outputs the current information including the current values of the three phases to the control device;
The power distributor according to claim 1.
The control device stores connection information indicating a relationship between each electronic device and a switching device connected to the electronic device,
By each electronic device, a current value indicating the magnitude of the current flowing through the electronic device is measured, and the current information including the measured current value is output,
The control device obtains the current information;
The control device calculates the three-phase current value based on the current information and the connection information, and selects the selected two phases for each switching device based on the three-phase current value.
The power distributor according to claim 1.
The control device receives the connection information from each electronic device;
The power distributor according to claim 9.
With a control device that controls a plurality of switching devices connected to a three-phase AC power source and connected to each of a plurality of electronic devices, current information indicating the magnitude of current measured at a plurality of locations is acquired,
By the control device, for each switching device, select the two phases of the three phases based on the current information and instruct the output of the selected two phases,
By each switching device, by outputting the indicated two phases of the three phases, to output a single-phase alternating current to the corresponding electronic device,
Power distribution method to do that.