JP2013009478A - Device of controlling power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly transition to an autonomous operation when an inverter detects a single operation or when a system voltage is reduced.SOLUTION: A bi-directional power conversion circuit 2 and inverter bridges 4u and 4v converting a power from a battery 1 into an AC voltage are provided. The inverter bridges are operated as a converter when the battery 1 is charged from a system power supply 13, and the inverter bridges are operated as an inverter when the battery is discharged. At an interconnected operation, interconnected relays 10u and 10v are turned on and autonomous relays 31u, 31v and 31n are turned off by an inverter output to supply a power to a single-phase three-wire load. System relays 30u and 30v arranged in series to the interconnected relays and operating with the autonomous relays are turned on to supply a power to the system power supply. In the case that the system voltage is lost, the interconnected relays are turned off and the system relays are turned off, and autonomous relays are turned on in conjunction with turning off of the system relays to switch over to an autonomous operation for supplying a power from the battery to the single-phase three-wire load.

Description

  Embodiments described herein relate generally to a control device for a power conditioner.

  2. Description of the Related Art Conventionally, when using natural energy, a technique for storing energy in a battery and converting it into alternating current using an inverter when necessary is known. In that case, a control device for the power conditioner is used to switch between a self-sustained operation using a battery and the use of electric power from the system.

The control device for the inverter is
(1) Charge the battery from the grid power supply.
(2) Supply energy discharged from the battery to the grid.
(3) When the system voltage is lost, the battery runs on its own and supplies power to the single-phase three-wire load.
Used for such applications. As this control apparatus, the thing of patent documents 1 and 2 is known, for example.

  As a control device for a power conditioner, a device using U-phase, N-phase, and V-phase half-bridge elements is known for converting electric power from a battery into a single-phase three-wire AC. However, this prior art requires one set of half-bridge elements for producing the N phase, and the circuit is complicated. In general, according to the difference in power capacity of the grid from the stand-alone operation from the battery side and the grid interconnection guidelines established by the power company, the conventional technology separates the load during stand-alone operation from the grid interconnection load. Provided. For this reason, it is necessary to switch the load in accordance with the independent operation and the grid connection.

JP 2003-018859 A Japanese Patent No. 3539455

The purpose of this embodiment is to make it possible to quickly shift to independent operation when the inverter detects isolated operation or when the system voltage decreases, and the system power supply and the independent power supply may interfere during operation. It is not to provide a control device for the inverter.
Another object of the present embodiment is to configure the control device for the power conditioner as described above with a simple circuit.

  In order to achieve the above object, the power conditioner control apparatus of the embodiment is characterized by the following points.

(1) A bidirectional power conversion circuit that converts electric power from the battery into an AC voltage and an inverter bridge are provided.
(2) When the battery is charged from the system power supply, the inverter bridge is operated as a converter, and when the battery is discharged, the inverter bridge is operated as an inverter to perform a linked operation of the battery and the system power supply.
(3) When the system voltage disappears, the operation is switched to the self-sustaining operation and the electric power from the battery is supplied to the single-phase three-wire load.
(4) At the time of interconnection operation, the interconnection relay is turned on and the independent relay is turned off to supply power to the single-phase three-wire load from the inverter output, and is arranged in series with the interconnection relay and interlocked with the autonomous relay. Turn on the grid relay to supply power to the grid power supply.
(5) When the system voltage disappears, the interconnection relay is turned off and the system relay is turned off, the self-supporting relay is turned on in conjunction with the system relay being turned off, and the single-phase three-wire load Switch to independent operation to supply power.

The circuit diagram of a 1st embodiment. The circuit diagram of a 2nd embodiment.

1. First Embodiment [Configuration]
A first embodiment will be described with reference to FIG.
Capacitors 3u and 3v are connected in series to the output of the bidirectional power conversion circuit 2 connected to the battery 1. A U-phase half-bridge circuit 4u and a V-phase half-bridge circuit 4v are connected to the output of the bidirectional power conversion circuit 2 in parallel with the capacitors 3u and 3v.

  The output of the U-phase half-bridge circuit 4u is connected to a U-phase interconnection relay 10u via a reactor 7u and a current detector 8u connected in series. The output of the U-phase interconnection relay 10u is connected to the U-phase of the AC power supply 13 through the system relay 30u and the circuit breaker 12u. The output of the V-phase half-bridge circuit 4v is connected to a V-phase interconnection relay 10v via a reactor 7v and a current detector 8v connected in series. The output of the V-phase interconnection relay 10v is connected to the V-phase of the AC power supply 13 through the system relay 30v and the circuit breaker 12v. The circuit breakers 12u and 12v are for safety switches and manually open / close with the system power supply 13.

  Filter capacitors 9u and 9v are connected to the U-phase and V-phase reactors 7u and 7v, respectively. The reactors 7u and 7v and the filter capacitors 9u and 9v absorb high-frequency components (output ripples) in the power of each phase. The other ends of the filter capacitors 9u and 9v are connected to an N-phase wiring extending from an intermediate point between the capacitors 3u and 3v connected in parallel with the bidirectional power conversion circuit 2.

  Autonomous relays 31u and 31v are connected in parallel to the U-phase and V-phase interconnection relays 10u and 10v, respectively. These self-supporting relays 31u and 31v are connected to the control circuit 21 via the b contact (normally open contact) 12b of the circuit breakers 12u, 12v and 12n and the b contact (normally open contact) 30b of the system relays 30u and 30v. ing.

On the other hand, the system relays 30u and 30v are connected to the control circuit 21 via b-contacts (normally-open contacts) 31b of the self-supporting relays 31u and 31v. This
(1) Independent relays 31u, 31v,
(2) Circuit breakers 12u-12n and system relays 30u, 30v
Only either (1) or (2) is input, and both (1) and (2) are not input simultaneously.

That is, the exciting winding for operating the self-supporting relays 31u to 31n is
(1) The circuit breakers 12u to 12n are turned off by the b contacts 12b of the circuit breakers 12u to 12n.
(2) The system relays 30u and 30v are turned off.
When the above two conditions are satisfied, the self-supporting relay 31 is turned on by exciting the winding.

  Further, since the b contacts 31b of the self-supporting relays 31u to 31n are connected in series to the system relays 30u and 30v, the system relays 30u and 30v are not turned on when the self-supporting relays 31u to 31n are turned on. The system power supply 13 and the independent power supply by the battery 1 are not mixed.

  The single-phase three-wire load 15 takes out 200V from two points of a connection point between the U-phase interconnection relay 10u and the system relay 30u and a connection point between the V-phase interconnection relay 10v and the system relay 30v. Moreover, 100V of the single-phase three-wire load 15 is taken out from the N phase of the circuit breaker 12n. In other words, when the battery is operated independently, the independent relays 31u to 31n are turned on, and the N phase taken out from the circuit breaker 12n is connected to the midpoint of the capacitors 3u and 3v through the independent relay 31n, and the half-bridge inverter Composed.

  The voltage of the battery 1 is detected by a voltage detection circuit 22 provided at its output end. The battery voltage detected by the voltage detection circuit 22 is input to the control circuit 21.

The control circuit 21 controls the gate drive circuits 18u and 18v of the half bridge circuits 4u and 4v, the interconnection relays 10u and 10v, the system relays 30u and 30v, and the independent relays 31u to 31n, and performs the following processing.
(1) When the battery is charged, the half bridge circuits 4u and 4v are operated as a converter, and when the battery is discharged, the half bridge circuits 4u and 4v are operated as an inverter.
(2) During the interconnection operation, the half bridge circuits 4u and 4v are operated as a grid interconnection inverter.
(3) During the independent operation, the half bridge circuits 4u and 4v are operated as an independent inverter.

  In addition, the control circuit 21 detects an abnormality or disappearance of the system voltage based on information from the current detectors 8u, 8v, the load 15, and the like, for example, information such as an abnormality in the frequency, voltage, and frequency change rate. According to the detection result, the control circuit 21 controls the gate drive circuits 18u and 18v of the half bridge circuits 4u and 4v to detect the single operation, and shuts off the U-phase and V-phase gate signals and switches to the independent operation. To supply power to the load.

[Action]
The operation of the present embodiment having the above configuration will be described.

(1) System interconnection operation When the circuit breakers 12u, 12v, and 12n are turned on, the b-contact 12b of the circuit breakers 12u, 12v, and 12n is opened, so that the self-supporting relays 31u to 31n are turned off. Therefore, the b contact 31 b of the self-supporting relays 31 u to 31 n is turned on, the winding connected to the b contact 31 b is excited, the system relays 30 u and 30 v are turned on, and the system power supply 13 is connected to the single-phase three-wire load 15. Connected.

  In this state, the control circuit 21 turns on the interconnection relays 10u and 10v to drive the half bridge circuits 4u and 4v as inverters. As a result, the battery 1 side and the system power supply 13 are connected to each other at 200 V AC at the connection point between the U-phase interconnection relay 10 u and the system relay 30 u and the connection point between the V-phase interconnection relay 10 v and the system relay 30 v. To go. As a result, power from the battery 1 can be supplied to the system or the load 15.

  On the other hand, when the battery 1 is charged by the system power supply 13, the battery is charged via the bidirectional power conversion circuit 2 by operating the half bridge circuits 4 u and 4 v as a converter by the control circuit 21.

(2) Independent operation detection When an abnormality or disappearance of the system voltage occurs, the control circuit 21 detects the abnormality or disappearance to detect an isolated operation. When the isolated operation is detected, the control circuit 21 cuts off the U-phase and V-phase gate signals and simultaneously turns off the interconnection relays 10u and 10v. As described above, the abnormality of the system power supply 13 is determined based on the frequency and voltage detected by the control circuit 21, changes in the frequency change rate, and the like. The control circuit 21 turns off the system relays 30u and 30v according to the abnormality determination result.

(3) Independent operation Next, independent operation will be described. Since the voltage from the system power supply 13 is not applied to the load 15, when the circuit breakers 12 u to 12 n are manually turned off, the control circuit 21 outputs an independent signal to the independent relay 31. Thereby, the conditions of the b contact 12b of the circuit breakers 12u to 12n and the b contact 30b of the system relays 30u and 30v are established, and the self-supporting relays 31u to 31n are turned on. In this case, when the self-supporting relays 31u to 31n are turned on, the coil of the system relays 30u and 30v includes the condition of the b contact 31b of the self-supporting relays 31u to 31n, so that the system relay 30 is locked in the off state. The

  In this state, U-phase and V-phase gate signals are output from the control circuit 21 to cause the herb bridge circuits 4u and 4v to perform a half-bridge operation between the midpoints of the capacitors 3u and 3v. Then, two sets of AC100V are output from the herb bridge circuits 4u and 4v, and one set of AC100V is output from between the middle points of the capacitors 3u and 3v. As a result, since the self-supporting relays 31u to 31v are turned on, a single-phase three-wire voltage is applied to the load 15, and the load starts operation.

[effect]
As described above, in the first embodiment, the circuit breakers 12u to 12n are manually turned off when the system is interrupted, thereby changing the connection to the load 15 that has been operated with the power of the system power supply 13. Without this, it is possible to automatically supply a single-phase three-wire self-supporting power source to the load 15. As a result, the operation of the load 15 can be reliably restarted with a simple operation of manually turning off the circuit breakers 12u to 12n. Further, since the N-phase half-bridge circuit is not required for generating the three-phase alternating current, the circuit configuration is simplified.

2. Second Embodiment [Configuration]
In the first embodiment, the self-sustaining operation is automatically performed by turning off the circuit breakers 12u to 12n. However, manual operation is still necessary. In the second embodiment, the circuit breaker is automatically switched from the grid operation to the independent operation without manually turning off the circuit breaker. The configuration of the second embodiment is shown in FIG.

  In the second embodiment, the voltage detection relay 40 is connected to the load side of the circuit breakers 12u and 12v. A contact (normally closed contact) 40 a of the voltage detection relay 40 is provided between the N phase of the system power supply 13 and the neutral point of the load 15. Similarly, the control circuit 21 is also provided with an a contact 40a of the voltage detection relay 10, and is configured to turn off the system relays 30u and 30v when the a contact 40a is opened. On the other hand, the b contact 40b of the voltage detection relay 40 is connected to the exciting coil of the self-supporting relay 31 instead of the b contact 12b of the circuit breakers 12u to 12n of the first embodiment.

[Action]
The operation of the second embodiment having such a configuration is as follows.
(1) System interconnection operation When the system power supply 13 is normally supplied and the circuit breakers 12u and 12v are on, the voltage value detected by the voltage detection relay 40 provided on the load side is also normal. Therefore, the a contact 40a of the voltage detection relay 40 provided between the N phase of the system power supply 13 and the neutral point of the load 15 is turned on, and the power from the system power supply 13 is supplied to the load 15.

  At the same time, since the b contact 40b of the voltage detection relay 40 is turned off, the self-supporting relays 31u to 31n are turned off. Accordingly, the b contact 31b of the self-supporting relays 31u to 31n is turned on, and the system relays 30u and 30v are turned on. As a result, the load 15 is supplied with single-phase three-wire power.

  When the interconnection relays 10u and 10v are turned on by a command from the control device 21, the U-phase and V-phase half-bridge circuits 4u and 4v operate as inverters. To be connected to the grid.

(2) Independent operation detection and independent operation When the system power supply 13 disappears, the control device 21 detecting this turns off the power elements used in the half-bridge circuits 4u and 4v and turns off the interconnection relays 10u and 10v. Turn off. When the voltage detection relay 40 is turned off due to the disappearance of the system power supply 13, the a contact 40a of the voltage detection relay 40 input to the control circuit 21 is opened, and the system relays 30u and 30v are turned off.

  When the b contact 40b of the voltage detection relay 40 and the b contact 30b of the system relays 30u and 30v are connected, the self-supporting relays 31u and 31v are turned on. As a result, the power supply to the exciting coil to which the b-contact 31b of the self-supporting relays 31u and 31v is connected is cut off, and the system relays 30u and 30v are turned off.

  After a certain time determined in advance from the operation time of each relay, the control device 21 drives the half bridge circuits 4u and 4v as inverters. As a result, the battery 1 operates independently and supplies a single-phase three-wire voltage to the load 15.

[effect]
In the present embodiment, even if the circuit breakers 12u and 12v are not manually turned off, it is possible to automatically switch to the independent operation and supply power to the load.

3. Other Embodiments Although the method for switching from the system power supply to the self-sustained power supply in the relay sequence has been described above, it goes without saying that these can also be achieved by control by digital logic or a microcomputer. Further, as shown in FIG. 2, the effect is the same even if the capacitor 9 of the filter is inserted on the 200V side. Moreover, you may use a power failure detection circuit instead of the voltage detection relay in FIG.

  In addition, the said embodiment is shown as an example in this specification, Comprising: It does not intend limiting the range of invention. In other words, the present invention can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof in the same manner as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Bidirectional power converter circuit 3u, 3v ... Capacitor 4u, 4v ... Half bridge circuit 7u, 7v ... Reactor 8u, 8v ... Current detector 9u, 9v ... Filter capacitor 10u, 10v ... Interlinked relay 12u, 12v , 12n ... circuit breaker 13 ... system power supply 15 ... load 18u, 18v ... gate drive circuit 21 ... control circuit 22 ... voltage detectors 30u, 30v ... system relays 31u, 31v, 31n ... self-sustaining relay 40 ... voltage detection relay

Claims (6)

It has a bidirectional power conversion circuit that converts power from the battery into AC voltage and an inverter bridge,
When charging the battery from the system power supply, the inverter bridge is operated as a converter, and when the battery is discharged, the inverter bridge is operated as an inverter, and the battery and the system power supply are connected.
In the control device of the power conditioner that supplies power from the battery to the single-phase three-wire load by switching to the independent operation when the system voltage disappears,
A power relay is connected to the single-phase three-wire load by turning on the relay and turning off the independent relay from the inverter output during the grid operation, and is connected in series with the grid relay and interlocking with the autonomous relay. Turn it on to supply power to the grid power supply,
When the system voltage disappears, turn off the grid relay and the system relay, turn on the self-sustaining relay in conjunction with the system relay off, and supply power from the battery to the single-phase three-wire load A control device for a power conditioner, characterized in that it switches to a self-sustaining operation.   2. The power conditioner control device according to claim 1, wherein the self-supporting relay and the system relay are interlocked with each other by a b-contact of the other party and are not simultaneously turned on.   The circuit breaker is provided between the system power supply and the single-phase three-wire load, and when the circuit breaker is turned off, the self-sustained relay is turned on to perform self-sustaining operation. The control apparatus of the power conditioner of 2. An inverter bridge has a configuration in which two capacitors connected in series are connected in parallel with the bidirectional conversion circuit, and two half-bridge circuits of U phase and V phase are connected in parallel with the bidirectional conversion circuit. With
When the self-supporting relay is turned on, the midpoint of the two capacitors on the DC side is connected to the N phase of the single-phase three-wire load,
The inverter control apparatus according to claim 1 or 2, wherein the inverter bridge shifts to a half-bridge operation. An AC power supply voltage detection relay is provided on the system power supply side of the system relay, and the b contact of this voltage detection relay is connected in series to the self-supporting relay,
The control of the power conditioner according to claim 1 or 2, wherein when the system voltage is detected to drop or disappear by the voltage detection relay, the self-sustained relay is turned on and the self-sustaining operation is started. apparatus. 5. The control apparatus for a power conditioner according to claim 4, wherein a filter capacitor that absorbs output ripple of the inverter is connected to output sides of two half-bridge circuits of U phase and V phase.

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