JP6210952B2 - Power supply system - Google Patents

Description

  According to the present invention, a power generation device and a power conversion device that bidirectionally converts AC power from the power line and DC power from the power storage device to a power line for supplying power to a load from the power system are close to the power system. The present invention relates to a power supply system connected in this order from the side.

  Conventionally, a photovoltaic power generation device that supplies power generated by connecting to a power system to a load, a distributed power generation device such as a fuel cell, and temporarily stores power from the power generation device and / or the power system. Many systems have been proposed that combine power storage devices that supply loads.

  For example, in Patent Document 1, a DC / DC converter that converts a voltage of DC power generated by a solar cell and a charger / discharger that charges and discharges a storage battery are connected by a DC system in a power conditioner. A solar power generation system is described in which DC power on the system side and AC power on the power system side to which a load is connected are bidirectionally converted by an AC / DC converter.

  The system described in Patent Document 1 is used for charging a storage battery without temporarily converting the generated power from the generator into alternating current, so that charging / discharging efficiency is good, but a DC / DC converter, and AC / DC Special control is required to add DC output power to the converter or charger / discharger. In addition, since the power conditioner is disconnected from the power system at the time of a power failure of the power system, there is a restriction that power is not supplied to a load connected to the power system.

  On the other hand, Patent Document 2 discloses a dispersion in which a charging / discharging device and a power generation device are connected in this order from the side close to the power system to an AC power line connecting the power system and the load (first power consuming device). Type power system is described. In this distributed power supply system, it is possible to supply AC power from the generator to the load and charge / discharge device on the premise that no reverse power flow is made to the power system when there is no power outage of the power system. The AC power from the charging / discharging device and the power generation device is supplied to the load.

  In the above distributed power supply system, it is necessary for the charging / discharging device to detect the power generation device by flowing a current to the load line between the self device and the power generation device in the event of a power failure. The order is as above. Further, in order to supply AC power from the power generator to the charge / discharge device on the power system side of the power generator and charge the storage battery during a non-power failure, the current flowing through the power line on the power system side of the charge / discharge device By switching so that is detected by the power generator, reverse power flow to the power system is prevented.

  On the other hand, Patent Document 3 describes a self-supporting power feeding system in which a power generation device and a charge / discharge device are connected in this order from the side close to the power system to an AC power line connecting between the power system and a load (power consumption device). Has been. In this self-sustained power supply system, similarly to the distributed power supply system described in Patent Document 2, it is possible to supply AC power from the power generator to the load and the charge / discharge device when the power system is not powered down. When the power system cannot supply power to the power line, AC power from the charging / discharging device and the power generation device that perform independent operation is supplied to the load.

  In the above self-sustained power supply system, it is necessary to cause the power generator to detect the current by flowing the current to the load side not only at the time of non-power failure but also at the time of power failure to the power line in which the power generator detects the current by the current transformer. . For this reason, a changeover switch is interposed in the power line between the power system and the current transformer, the power line is disconnected at the time of a power failure by this switch, and the power generator from the power line in which the current from the charging / discharging device is disconnected. It is supplied to the load.

JP 2013-172514 A JP 2014-39385 A JP 2013-176180 A

  However, in the technologies disclosed in Patent Documents 2 and 3, when the charging / discharging device performs a self-sustained operation, the power generation device generates power so that current does not flow in the direction opposite to the load side through the power line that detects the current. Therefore, a part or all of the generated power is not charged in the storage battery of the charging / discharging device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to charge a power storage device with surplus power generated by a power generation device when the power conversion device performs a self-sustaining operation. It is to provide a power supply system.

  A power supply system according to the present invention includes a detection unit that detects a current flowing in a power line for supplying power to a load from an electric power system and outputs a signal indicating a detection result, and is connected to the power line between the detection unit and the load. Connected to the power line between the power generation device and the load, and the AC power from the power line and the power storage device are connected to the power generation device that controls the generated power based on the signal acquired from the detection unit. A power supply system including a power conversion device that bi-directionally converts DC power into a second, and detects a current flowing in the power line between the power conversion device and a load, and outputs a second signal related to a detection result And a changeover switch that switches a source of a signal acquired by the power generation device to either the detection unit or the second detection unit, and the power conversion device includes the power storage device. When the power conversion device performs a self-sustained operation, the signal acquisition destination is the second switch by the changeover switch. It is characterized in that it is switched to the detection unit.

In the power supply system according to the present invention, when the AC voltage from the power generator exceeds a reference voltage to be output in the self-sustained operation, the power converter is a DC power obtained by AC / DC conversion of the AC power from the power generator. The power storage device is charged .

The power supply system according to the present invention includes a disconnection detection unit that detects a disconnection from the power system, and the power converter performs a self-sustained operation when the disconnection detection unit detects the disconnection. It is characterized by that.

  In the power supply system according to the present invention, the power conversion device includes a switching unit that switches the signal acquisition source to the second detection unit by the changeover switch when the disconnection detection unit detects a disconnection. It is characterized by that.

  In the power supply system according to the present invention, the power conversion device acquires an SOC of the storage battery included in the power storage device when the switching unit is switched to the second detection unit, and the acquisition unit acquires Means for determining whether or not the determined SOC is greater than a predetermined threshold, and second switching means for switching the signal acquisition source to the detection unit by the changeover switch when the means is determined to be large. It is characterized by.

In the power supply system according to the present invention, when the second switching unit switches to the detection unit, the power conversion device is configured such that the SOC acquired by the acquiring unit is equal to or less than a second threshold value smaller than the predetermined threshold value. Means for determining whether or not there is, and means for switching the acquisition source of the signal to the second detection unit by the changeover switch when the means is determined to be as follows.

  In the power supply system according to the present invention, the power conversion device has an H bridge circuit in which a parasitic diode or a commutation diode is connected in parallel to a switching element included in each arm, and both DC power and AC power are supplied. It is characterized by comprising an inverter that converts the direction.

  The electric power supply system which concerns on this invention is connected to the said electric power line between the said detection part and an electric power grid | system, and is provided with the solar power generation device which produces electric power using sunlight.

  In the present invention, the detection unit detects the current flowing through the power line for supplying power to the load from the power system, outputs a signal indicating the detection result, and is connected to the load-side power line from the detection unit. Controls the generated power based on the signal acquired from the detection unit, and the power converter connected to the power line on the load side of the power generator converts AC power from the power line and DC power from the power storage device bidirectionally. Then, the power storage device is charged and discharged. In addition, the second detection unit outputs a second signal related to the detection result of the current flowing in the power line between the power conversion device and the load, and the acquisition source of the signal for the power generation device to control the generated power is It is possible to switch to either the detection unit or the second detection unit by a changeover switch. When the power conversion device performs the self-sustained operation with this configuration, the acquisition source of the signal viewed from the power generation device 8 is switched from the detection unit to the second detection unit by the changeover switch.

  As a result, the power generation device performs the interconnection operation linked to the independent operation of the power conversion device, and generates the generated power based on the second signal related to the detection result of the current flowing through the power line on the load side of the power conversion device. Control. In this case, current inevitably flows from the power conversion device to the load side, and the detection result related to the signal output from the second detection unit is detected when a current in the opposite direction to the reverse power flow is detected. It corresponds to the result. For this reason, the power generation device that is not concerned with switching the signal acquisition destination by the changeover switch continues to generate power in the same manner as when a signal indicating that a current in the direction opposite to the reverse power flow is detected is acquired from the detection unit. AC power is supplied to the power converter and the load.

In the present invention, when the disconnection detection unit detects the disconnection of the own system from the power system, the power converter converts the DC power from the power storage device into AC power and supplies the load to the load. Do.
Thereby, for example, when a power failure of the power system is detected and the system is disconnected from the power system, the power conversion device to be connected to the power generator starts independent operation.

  In the present invention, when a part of the AC power from the power generator becomes surplus power with respect to the power consumed by the load during the autonomous operation of the power converter, the AC voltage at the output terminal of the power converter is It will exceed the reference voltage in autonomous operation. In this case, the power conversion device takes in AC power from the power generation device, converts it into DC power, and charges the power storage device with the converted DC power. Thereby, since the surplus electric power from a power generator is taken in into an electrical storage apparatus, the alternating voltage in the output terminal of a power converter device is maintained at a reference voltage.

In the present invention, when the system is disconnected from the power system, the power conversion device captures the detection result of the disconnection detection unit and controls the changeover switch, and detects the acquisition source of the signal viewed from the power generation device. To the second detector.
This eliminates the need for an additional circuit that switches the changeover switch according to the detection result of the disconnection detection unit, for example, and further switches the acquisition source of the signal from the second detection unit to the detection unit by the changeover switch (that is, switching). The condition for returning can be arbitrarily set.

In the present invention, after the power conversion device controls the changeover switch and switches the acquisition source of the signal viewed from the power generation device from the detection unit to the second detection unit, the charging of the power storage device continues. When the SOC of the storage battery included in the power storage device becomes greater than a predetermined threshold, the power conversion device controls the changeover switch to switch the acquisition source of the signal from the second detection unit to the detection unit.
In this case, the detection unit does not detect a current in the opposite direction to the reverse power flow, and it is not guaranteed that no reverse power flow occurs, so the power generation device stops power generation.

In the present invention, after the power conversion device controls the changeover switch and switches the acquisition source of the signal viewed from the power generation device from the second detection unit to the detection unit, the acquired SOC of the storage battery is the predetermined value. When it becomes below the 2nd threshold value smaller than a threshold value, a power converter switches the acquisition place of the said signal from a detection part to a 2nd detection part.
As a result, when discharging progresses until charging can be accepted by the power storage device, power generation is resumed based on the detection result of the second detection unit that detects the current in the direction opposite to the reverse power flow.

In the present invention, DC power and AC power are bidirectionally transmitted by an inverter using an H bridge (full bridge) in which a parasitic diode or a commutation (reflux) diode is connected in parallel to a switching element included in each arm. Convert.
As a result, when the AC voltage applied from the power generator is higher than the AC voltage that the inverter attempts to output when converting DC power to AC power, the AC power from the power generator is The power is rectified by the diode or the commutation diode and converted into DC power, and the power storage device is charged with the converted DC power.

In the present invention, a solar power generation device that generates power using sunlight is connected to the power line between the detection unit and the power system.
Thereby, since the electric power generated by the solar power generation device is supplied to the power conversion device and the load, surplus power that is not consumed by the load is converted into DC power by the power conversion device and is temporarily charged in the power storage device.

According to the present invention, the current flowing from the power converter connected to the load-side power line to the load side from the power generator and flowing to the load side is detected by the second detection unit, and the second signal related to the detection result is Acquired by the generator. For this reason, the power generation device that is not concerned with switching the signal acquisition destination by the changeover switch continues to generate power in the same manner as when a signal indicating that a current in the direction opposite to the reverse power flow is detected is acquired from the detection unit. AC power is supplied to the power converter and the load.
Therefore, when the power conversion device performs a self-sustained operation, it becomes possible to charge the storage battery of the power conversion device with the surplus power generated by the power generation device.

It is a block diagram which shows the structural example of the electric power supply system which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the flow of the electric power feeding at the time of the non-power failure of the electric power supply system which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the flow of the electric power feeding at the time of the power failure of the electric power supply system which concerns on Embodiment 1 of this invention. 3 is a circuit diagram illustrating a configuration example of an inverter 3. FIG. It is a flowchart which shows the process sequence of CPU which controls switching from a grid operation to a self-sustained operation with the power converter device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process sequence of CPU which switches on / off of a relay contact (switch) in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structural example of the electric power supply system which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the flow of the electric power feeding at the time of the non-power failure of the electric power supply system which concerns on Embodiment 4 of this invention. It is explanatory drawing which shows the flow of the electric power feeding at the time of the power failure of the electric power supply system which concerns on Embodiment 4 of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of a power supply system according to Embodiment 1 of the present invention.
In the figure, reference numeral 1 denotes a power conversion device. The power conversion device 1 receives DC power from a storage battery 41 (refer to FIG. 2 described later) of an electric vehicle (corresponding to a power storage device: hereinafter referred to as an EV (Electric Vehicle)) 4. The inverter 3 which converts into single-phase alternating current power, and the control part 10 which instruct | indicates the content of conversion to the inverter control circuit 20 which controls the conversion of the electric power by this inverter 3 are provided. The interface between the power converter 1 and the EV 4 conforms to, for example, the CHAdeMO method proposed by the CHAdeMO Council. The power converter device 1 may incorporate a storage battery.

  The control unit 10 includes a CPU (Central Processing Unit) 11. The CPU 11 includes a ROM 12 that stores information such as programs, a RAM 13 that stores temporarily generated information, and a timer 14 that measures various times. They are bus connected to each other. The CPU 11 also has a CAN communication unit 15 for performing communication with the EV 4 via a CAN (Controller Area Network), an I / O port 16 for interfacing with various circuits described later, and an operation display unit 27. A panel I / F unit 17 for interfacing with the bus is connected to the bus. The operation display unit 27 includes a button for accepting an operation by the user, a touch panel, and an LCD.

  The inverter 3 is a bidirectional type that can also convert AC power into DC power. The storage battery 41 of the EV 4 is charged by the DC power converted from the AC power by the inverter 3. The AC side of the inverter 3 is connected to the bus in the distribution board 5 through the electric circuit 31, the relay contact 32 a of the disconnecting relay 32, the electric circuit 33, and the branch breaker 53 arranged in the distribution board 5. 50.

  The electric circuit 31 is connected to a voltage detection circuit 21 that detects an AC voltage of the electric circuit 31. A drive coil 32 c that drives the relay contact 32 a is connected to the relay drive circuit 22. The inverter control circuit 20, the voltage detection circuit 21 and the relay drive circuit 22 are connected to the I / O port 16. The voltage detection circuit 21 may detect the AC voltage of the electric circuit 33.

  The bus 50 is a power line for feeding power from the power system 7 to the loads 61 and 62 via the connection point of the branch breaker 53. Between the bus 50 and the power system 7, a relay contact 55a of the disconnect relay 55 and a main breaker 56 are connected in series. Each of the loads 61 and 62 is connected to the bus 50 via the branch breakers 51 and 52. A current transformer (corresponding to a second detection unit) 66 is coupled to a power line between the connection point of the branch breaker 53 and the connection point of the branch breakers 51 and 52 in the bus 50.

  The power generation device 8 is connected to the power line between the connection point of the branch breaker 53 and the connection point of the relay contact 55 a in the bus 50 via the branch breaker 57. A current transformer 63 is coupled to the power line between the connection point of the branch breaker 53 and the connection point of the branch breaker 57 in the bus 50. A current transformer (corresponding to a detector) 65 is coupled to a power line between the connection point of the branch breaker 57 and the connection point of the relay contact 55a in the bus 50.

  The current transformer 66 is connected to a NO (Normally Open) terminal of a c-contact type relay contact (corresponding to a changeover switch) 64a of a relay 64 made of, for example, a semiconductor relay or a photomoss relay. The current transformer 63 is connected to a current detection circuit 23 that detects a current flowing through the primary coil of the current transformer 63. The current transformer 65 is connected to the NC (Normally Close) terminal of the relay contact 64a. A drive coil 64 c that drives the relay contact 64 a is connected to the relay drive circuit 24.

  Note that switching of the current transformers 65 and 66 requires two circuit relay contacts, but for the sake of simplicity, only one circuit relay contact 64a is shown in FIG. The same applies to other relay contacts, breakers and the like. The current transformers 65 and 66 preferably include an overvoltage clamp element. The current transformer 65 or 66 that is opened when the relay contact 64a is switched may be short-circuited.

  The drive coil 55c that drives the relay contact 55a is connected to a relay drive monitoring circuit (corresponding to the disconnection detection unit) 25 together with both ends of the auxiliary contact 551 that outputs a contact signal indicating the on / off state of the disconnection relay 55. Yes. A power failure detector 26 is connected to the electrical path between the relay contact 55 a and the main breaker 56. The current detection circuit 23, the relay drive circuit 24, the relay drive monitoring circuit 25, and the power failure detector 26 are connected to the I / O port 16.

  The power generation device 8 includes a power generation unit 81 formed of a fuel cell, an inverter 82 that converts DC power generated by the power generation unit 81 into AC power, and a control that controls power conversion by the inverter 82 and power generation by the power generation unit 81. Part 83. The AC side of the inverter 82 is connected to the branch breaker 57 via the relay contact 84 a of the disconnection relay 84. A drive coil 84 c that drives the relay contact 84 a is connected to the control unit 83. The controller 83 is also connected to a COM (Common) terminal of the relay contact 64a. The power generation device 8 is a general-purpose device including a fuel cell, but is not limited to this, and may be another power generation device including a power generation unit other than the fuel cell.

  The control unit 83 controls the inverter 82 so as to perform an interconnection operation in which an AC voltage is output in conjunction with a main body that applies an AC voltage to the bus 50. In this case, the disconnect relay 84 is controlled to be turned on by the control unit 83. During the interconnection operation, the control unit 83 controls power generation by the power generation unit 81 based on a signal indicating the current detection result by the current transformer 65 or a signal indicating the current detection result by the current transformer 66. Specifically, the control unit 83 determines that the current flowing through the bus 50 to which the current transformer 65 or 66 switched by the relay contact 64a is coupled is opposite to the current flowing toward the loads 61 and 62, that is, the reverse power flow. When the current is the current, the power generation unit 81 continues the power generation, and when the current flows to the power system 7 side, the power generation unit 81 is stopped.

  In the above-described configuration, the main breaker 56 and the branch breakers 51, 52, 53, 57 of the distribution board 5 are closed and closed, and the power failure detector 26 detects whether or not the power system 7 has a power failure. . The detection result is taken into the CPU 11. When the power system 7 is not out of power, the CPU 11 controls the disconnect relay 55 to be turned on using the relay drive monitoring circuit 25, so that the AC voltage from the power system 7 is applied to the bus 50. Then, the power generation device 8 performs an interconnection operation linked to the power system 7 and supplies AC power to the loads 61 and 62. However, in this case, since the relay contact 64a is off and the COM terminal is connected to the NC terminal, the power generation device 8 causes the current flowing through the bus 50 to which the current transformer 65 is coupled to the loads 61 and 62 side. When it becomes current, it generates electricity.

  On the other hand, the power conversion device 1 performs an operation for converting DC power from the storage battery 41 of the EV 4 into AC power or an operation for converting AC power from the bus 50 into DC power according to the setting from the operation display unit 27. It is selected whether to perform or not perform any operation. When performing any of the operations, the CPU 11 controls the disconnect relay 32 to be turned on using the relay drive circuit 22 and instructs the inverter control circuit 20 of the operation details.

  The operation in which the power conversion device 1 converts the DC power into the AC power when the power system 7 is not interrupted is an interconnected operation linked to the power system 7. The voltage of the electric circuit 31 during the interconnection operation and the detection result of the current flowing through the bus 50 to which the current transformer 63 is coupled are taken into the CPU 11 from the voltage detection circuit 21 and the current detection circuit 23, respectively. The CPU 11 gives an instruction to the inverter control circuit 20 so that the current flowing through the bus 50 to which the current transformer 63 is coupled becomes a current flowing toward the loads 61 and 62, that is, a current opposite to the reverse power flow.

  Here, when the power system 7 fails, or when the main breaker 56 is manually opened, when the detection result of the power failure is taken into the CPU 11 from the power failure detector 26, the CPU 11 is solved by the relay drive monitoring circuit 25. The power converter 1 and the power generator 8 are disconnected from the power system 7 by controlling the column relay 55 to be off.

  Further, the CPU 11 takes in the contact signal of the auxiliary contact 551 by the relay drive monitoring circuit 25 and confirms that the disconnecting relay 55 is in an OFF state, and then drives the relay contact 64a to be ON and is independent from the inverter 3. Start driving. Thereby, the electric power generating apparatus 8 performs the interconnection operation linked to the autonomous operation of the power conversion apparatus 1. In this case, since the COM terminal of the relay contact 64a is connected to the NO terminal, the power generation device 8 allows the current flowing through the bus 50 to which the current transformer 66 is coupled to the load 61, 62 side. Continue power generation.

  When the power conversion device 1 performs a self-sustained operation, the inverter control circuit 20 performs control so that the voltage and frequency of the AC power output from the inverter 3 to the electric circuit 31 are the target voltage and the target frequency instructed from the CPU 11, respectively. . In the first embodiment, a standard target voltage and a target frequency are set to a reference voltage (for example, 200 V) and a reference frequency (for example, 50.0 Hz or 60.0 Hz).

Hereinafter, the behavior of the power conversion device 1 and the power generation device 8 in the power supply system will be described with reference to the drawings.
FIG. 2 is an explanatory diagram showing the flow of power supply during a non-power failure of the power supply system according to Embodiment 1 of the present invention, and FIG. 3 is during a power failure of the power supply system according to Embodiment 1 of the present invention. It is explanatory drawing which shows the flow of electric power feeding. In the figure, reference numeral 41 denotes a storage battery included in the EV 4. In particular, in FIG. 2, the relay contact 64a is not driven on and the COM terminal is connected to the NC terminal, whereas in FIG. 3, the relay contact 64a is driven on and the COM terminal is connected to the NO terminal. Is different. 2 and 3, the flow of AC power from the power system 7 is indicated by black arrows, the flow of AC power from the power generator 8 is indicated by white arrows, and the flow of AC power from the power converter 1 is parenthesized. Shown with a black arrow. The main circuit breaker 56, branch breakers 51, 52, 53, 57, the electric circuit 33, etc. are not shown.

  In FIG. 2, the power generation device 8 is connected to the power system 7, converts the DC power generated by the power generation unit 81 into AC power by the inverter 82, and supplies the AC power to the bus 50 with a constant current. In this case, the current flowing through the bus 50 to which the current transformer 65 connected to the NC terminal of the relay contact 64a is coupled is controlled so as to be in the direction opposite to the reverse power flow. Such control is normally performed by a general-purpose power generator including a fuel cell. When the power conversion device 1 stops conversion, the AC power (hereinafter, generated power) from the power generator 8 is compared with the AC power (hereinafter referred to as power consumption) consumed by the loads 61 and 62 including the electrical equipment. When the power supply is insufficient, the shortage of AC power is supplied from the power system 7.

  When the power converter 1 converts the AC power from the bus 50 into DC power and charges the storage battery 41, the generated power indicated by the white arrow is diverted and flows into the power converter 1 and the loads 61 and 62. . In this state, when the generated power is less than the sum of the power consumption and the power flowing into the power conversion device 1, the shortage of AC power is supplied from the power system 7.

  When the generated power is at least greater than the consumed power, the power of the same amount as the surplus power obtained by subtracting the consumed power from the generated power or the power slightly larger than the surplus power is converted into DC power by the power conversion device 1 and the storage battery 41 It is preferable to control so as to be charged. For that purpose, for example, it is necessary to sequentially detect generated power and consumed power to calculate surplus power, and control so that AC power greater than the calculated surplus power is converted by the power conversion device 1. However, since such control is beyond the scope of the present invention, only that possibility is described here.

  On the other hand, when the power conversion device 1 converts the DC power from the storage battery 41 into AC power and supplies it to the loads 61 and 62, it is a major premise that the generated power does not exceed the power consumption. Furthermore, it is necessary to perform control so that power having the same magnitude as power obtained by subtracting generated power from power consumption (hereinafter referred to as insufficient power) or AC power less than the insufficient power is supplied from the power conversion device 1. When controlled in this way, the loads 61 and 62 include all of the generated power indicated by white arrows, AC power from the power system 7 indicated by black arrows, and power indicated by black arrows with parentheses. AC power from the converter 1 flows in.

  In order to supply AC power less than the above shortage power from the power converter 1, for example, the generated power and the power consumption are sequentially detected to calculate the shortage power, and the AC power less than the calculated shortage power is calculated. It is necessary to control the power converter 1 so that it is converted. However, since such control is beyond the scope of the present invention, only that possibility is described here.

  Moving to FIG. 3, when the power system 7 fails or when the main breaker 56 is manually opened, the power conversion device 1 confirms that the disconnect relay 55 is in the off state as described above. The relay contact 64a is driven to be turned on so that the COM terminal is connected to the NO terminal, and the inverter 3 is switched to the independent operation. That is, the CPU 11 gives an instruction to the inverter control circuit 20 so that the inverter 3 converts the DC power from the storage battery 41 into AC power and supplies it to the bus 50. In this case, the target voltage and the target frequency are set and instructed to the inverter control circuit 20 so that the AC voltage applied to the bus 50 by the inverter 3 becomes the above-described reference voltage and reference frequency.

  One power generation device 8 does not know that the connection destination of the COM terminal of the relay contact 64a has been switched from the current transformer 65 to the current transformer 66, and the current transformer 66 to which the COM terminal is connected is coupled. The generated power is controlled so that the current flowing through the bus 50 is in a direction opposite to the reverse power flow. By the way, in the state shown in FIG. 3, at least AC power from the power converter 1 is inevitably supplied to the loads 61 and 62, so the bus 50 to which the current transformer 66 is coupled must be connected to the loads 61 and 62 side. Current will flow to As a result, the power generation device 8 can continue the operation by performing the interconnection operation linked to the independent operation of the power conversion device 1.

  As described above, when the connection destination of the COM terminal of the relay contact 64a is the current transformer 66, the signal indicating the current detection result by the current transformer 66 is a signal indicating the current in a certain direction. For this reason, a circuit that generates a dummy signal that simulates a signal indicating the current in the certain direction may be connected to the NO terminal of the relay contact 64a in place of the current transformer 66. Hereinafter, the signal indicating the current detection result by the current transformer 66 and any one of the dummy signals are referred to as a “second signal related to the current detection result by the current transformer 66”.

  When the power converter 1 performs a self-sustained operation, the power consumption consumed by the loads 61 and 62 is insufficient with only the AC power indicated by the white arrows that the power generator 8 supplies to the loads 61 and 62 via the bus 50. While this occurs, insufficient power is supplied from the power conversion device 1 to the loads 61 and 62.

  On the other hand, when the AC power that the power generator 8 should supply to the loads 61 and 62 via the bus 50 exceeds the power consumed by the loads 61 and 62, the surplus power is converted to DC power by the power converter 1. It is converted and used for charging the storage battery 41. Thereby, since the voltage rise of bus 50 is suppressed, the alternating voltage of bus 50 is maintained at the above-mentioned reference voltage. Switching of the conversion direction in the power converter 1 is autonomously performed by the inverter 3, for example. That is, when the AC voltage of the bus 50 exceeds the reference voltage output by the inverter 3 as the target voltage, the inverter 3 converts the AC power into DC power so that the regenerative power is regenerated to the DC side. To do.

Next, the operation of the inverter 3 having the above function will be described with reference to a specific example.
FIG. 4 is a circuit diagram illustrating a configuration example of the inverter 3. The inverter 3 includes switching elements such as IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors), and power transistors in an H-bridge. In the first embodiment, switches Q1, Q2, Q3, Q4 made of IGBT are used as switching elements. The collectors and emitters of the switches Q1, Q2, Q3, and Q4 are connected to the cathodes and anodes of commutation (reflux) diodes (hereinafter simply referred to as diodes) D1, D2, D3, and D4.

  The collectors of the switches Q1 and Q3 included in each of the upper arms of the H bridge are connected to one end of the smoothing capacitor C1 and connected to the plus side of the electric circuit for connecting to the EV4 via the inductor L1. The emitters of the switches Q2 and Q4 included in each of the lower arms of the H bridge are connected to the other end of the smoothing capacitor C1 and to the negative side of the electric circuit for connecting to the EV4.

  The emitter of the switch Q3 is connected to the collector of the switch Q4, and is connected to one end of the smoothing capacitor C2 and one of the pair of electric paths 31 (shown by one line in FIG. 1) via the inductor L2. The emitter of the switch Q1 is connected to the collector of the switch Q2, and is connected to the other end of the smoothing capacitor C2 and the other of the pair of electric paths 31 via the inductor L3. The gates of the switches Q1, Q2, Q3, and Q4 are connected to the inverter control circuit 20. The inverter control circuit 20 includes a drive circuit that drives these switches Q1, Q2, Q3, and Q4.

  In FIG. 4, when the DC power from the EV 4 is converted into AC power, the inverter 3 operates as a step-down DC / AC inverter, for example. Moreover, when converting the alternating current power from the electric circuit 31 into direct current power, the inverter 3 operates as a step-up AC / DC converter (that is, a switching power supply), for example. Hereinafter, the conversion operation will be specifically described. When the disconnection relay 32 is in the on state and the branch breaker 53 is closed, the AC voltage of the electric circuit 31 and the AC voltage of the bus 50 are the same.

When converting DC power from EV4 to AC power,
(A) By driving the switches Q3 and Q2 on / off by the PWM signal from the inverter control circuit 20, a voltage corresponding to one half wave of the AC voltage forming a sine wave is generated, and the generated voltage is expressed as L2. , L3 and C2 for smoothing.
(B) By driving the switches Q1 and Q4 on / off by the PWM signal from the inverter control circuit 20, a voltage corresponding to the other half wave of the AC voltage forming a sine wave is generated, and the generated voltage is expressed as L3 , L2 and C2 for smoothing.

When converting AC power from the electric circuit 31 to DC power,
(A) During the period corresponding to one half wave of the AC voltage forming the sine wave, the switch Q4 is connected to the PWM from the inverter control circuit 20 during the period when the voltage at one end is positive with respect to the other end of the smoothing capacitor C2. When driven on by a signal, a current flows through the path of the inductor L2, the switch Q4, the diode D2, and the inductor L3, and energy is stored in the inductors L2 and L3.
(B) When the switch Q4 is turned off, current flows back to the path of the inductor L2, the diode D3, the inductors L1, EV4, the diode D2, and the inductor L3, and the energy of the inductors L2 and L3 is released.
(C) During the period corresponding to the other half wave of the AC voltage forming the sine wave, the switch Q2 is connected to the PWM from the inverter control circuit 20 during the period when the voltage at one end is negative with respect to the other end of the smoothing capacitor C2. By driving on by the signal, a current flows through the path of the inductor L3, the switch Q2, the diode D4, and the inductor L2, and energy is stored in the inductors L3 and L2.
(D) When the switch Q2 is turned off, current flows back to the path of the inductor L3, the diode D1, the inductors L1, EV4, the diode D4, and the inductor L2, and the inductors L3 and L2 release energy.

  Now, as indicated by the black arrows with parentheses in FIG. 3, the AC power from the power generator 8 is consumed by the loads 61 and 62 while the inverter 3 of the power converter 1 is converting the DC voltage into the AC voltage. When the electric power exceeds the generated power, the AC voltage of the bus 50, that is, the AC voltage of the electric circuit 31, exceeds the reference voltage that the inverter 3 outputs as the target voltage. For this reason, the voltage exceeding the reference voltage actively output by the inverter 3 among the AC voltage of the electric circuit 31 is the path of the inductor L2, the diode D3, the inductors L1, EV4, the diode D2 and the inductor L3, and the inductor L3, the diode. Rectification is performed in the path of D1, inductors L1, EV4, diode D4, and inductor L2.

  As a result, of the AC power from the power generation device 8, AC power that is not consumed by the loads 61 and 62, that is, surplus power, is taken into the inverter 3 from the bus 50 through the electric paths 33 and 31 and converted into DC power. The Therefore, the voltage rise from the reference voltage in the electric paths 31 and 33 and the bus 50 is suppressed, and the state shown in FIG. 3 continues stably.

Below, operation | movement of the control part 10 of the power converter device 1 mentioned above is demonstrated using the flowchart which shows it. The processing shown below is executed by the CPU 11 in accordance with a control program stored in advance in the ROM 12.
FIG. 5 is a flowchart illustrating a processing procedure of the CPU 11 that controls switching from the grid operation to the independent operation in the power conversion device 1 according to the first embodiment of the present invention. The processing of FIG. 5 is started at a constant cycle (for example, every second) during the interconnected operation of the power conversion device 1. Before a power failure is detected, the “switch flag” is set to off.

  When the process of FIG. 5 is started, the CPU 11 determines whether or not a power failure of the power system 7 is detected by the power failure detector 26 (S11). The power failure here includes a case where the main breaker 56 is manually opened. When no power failure is detected (S11: NO), the CPU 11 ends the process of FIG. 5 without executing any special process.

  When a power failure is detected in step S11 (S11: YES), the CPU 11 controls the disconnect relay 55 in the distribution board 5 to be turned off by the relay drive monitoring circuit 25 (S12), and waits for, for example, 50 ms (S13). . This 50 ms allows for the time from when the drive coil 55c is driven until the ON / OFF state of the contact signal output from the auxiliary contact 551 is stabilized, and is not limited to 50 ms. Thereafter, the CPU 11 determines whether or not the disconnection from the power system 7 is detected by the auxiliary contact 551 and the relay drive monitoring circuit 25 (S14), and when the disconnection is not detected (S14: NO), more The process of FIG. 5 is terminated without executing the process of FIG.

  When disconnection is detected in step S14 (S14: YES), the CPU 11 drives the relay contact (switch) 64a to be turned on by the relay drive circuit 24 so that the COM terminal is connected to the NO terminal (S15). : Equivalent to the switching means) and a switching flag is set to ON to memorize that the relay contact 64a is driven ON (S16). Next, the CPU 11 instructs the inverter control circuit 20 to perform the independent operation of the inverter 3 (S17), controls the disconnect relay 32 of the own device to be on (S18), and ends the process of FIG.

  When it is detected that the present system has been disconnected from the power system 7 and the power conversion device 1 is switched to the self-sustained operation, the power failure of the power system 7 is restored, or the main breaker 56 is manually closed The disconnection relay 55 can be controlled to be turned on, the relay contact 64a can be turned off, and the power conversion apparatus 1 can be switched to the interconnected operation to continue the operation of the system. Do not explain.

  As described above, according to the first embodiment, the current transformer 65 detects the current flowing through the bus (power line) 50 for supplying power to the loads 61 and 62 from the power system 7 and outputs a signal indicating the detection result. The power generation device 8 connected to the power lines closer to the loads 61 and 62 than the current transformer (detection unit) 65 via the branch breaker 57 generates the generated power based on the signal acquired from the current transformer 65 via the relay contact 64a. The power converter 1 connected to the power lines closer to the loads 61 and 62 than the power generator 8 bi-directionally converts the AC power from the power line and the DC power from the EV 4 bidirectionally to charge and discharge the EV 4. Further, the current transformer (second detection unit) 66 or a circuit that generates a dummy signal outputs a second signal related to the detection result of the current flowing through the power line between the power converter 1 and the loads 61 and 62. The signal acquisition source for the power generation device 8 to control the generated power can be switched to either the current transformer 65 or the current transformer 66 by a relay contact (switch) 64a. When the power conversion device 1 performs the self-sustained operation with this configuration, the acquisition source of the signal viewed from the power generation device 8 is switched from the current transformer 65 to the current transformer 66 by the relay contact (switch) 64a.

Thus, the second signal related to the detection result of the current flowing through the power lines closer to the loads 61 and 62 than the power conversion device 1 while the power generation device 8 performs the interconnection operation linked to the independent operation of the power conversion device 1. The generated power is controlled based on the above. In this case, a current inevitably flows from the power conversion device 1 to the loads 61 and 62, and the detection result related to the signal output from the current transformer 66 indicates that a current in the direction opposite to the reverse power flow is detected. Corresponds to the detection result. For this reason, the power generation apparatus 8 that is not concerned with switching of the signal acquisition destination by the relay contact 64a generates power in the same manner as when the signal indicating that the current in the direction opposite to the reverse power flow is detected is acquired from the current transformer 65. The AC power is continuously supplied to the power conversion device 1 and the loads 61 and 62.
Therefore, when the power conversion device 1 performs a self-sustained operation, it is possible to charge the EV 4 with the surplus power generated by the power generation device 8. Moreover, it becomes possible to continue the self-sustained operation of the power converter 1 for a longer time than in the case where the surplus power of the power generator 8 is not charged to the EV 4.

Furthermore, according to the first embodiment, when the disconnection of the own system from the power system 7 is detected by the auxiliary contact 551 of the disconnection relay 55 and the relay drive monitoring circuit 25 (disconnection detection unit), the power conversion device 1 performs a self-sustaining operation in which DC power from the EV 4 is converted into AC power and supplied to the loads 61 and 62.
Therefore, for example, when a power failure of the power system 7 is detected and the system is disconnected from the power system 7, the power conversion device 1 that should be a connection destination of the power generation device 8 can start a self-sustaining operation.

Further, according to the first embodiment, when a part of the AC power from the power generation device 8 becomes surplus power with respect to the power consumed by the loads 61 and 62 during the autonomous operation of the power conversion device 1, the power conversion The AC voltage at the output end of the device 1 will exceed the reference voltage in the independent operation. In this case, the power conversion device 1 takes in AC power from the power generation device 8 and converts it into DC power, and charges the storage battery 41 of the EV 4 with the converted DC power.
That is, since surplus power from the power generation device 8 is taken into the EV 4, the AC voltage at the output end of the power conversion device 1 can be maintained at the reference voltage.

Furthermore, according to the first embodiment, when the system is disconnected from the power system 7, the power conversion device 1 takes in the detection result by the auxiliary contact 551 and the relay drive monitoring circuit 25 (disconnection detection unit) and relays it. The contact (switch) 64 a is driven to turn on, and the signal acquisition source viewed from the power generation device 8 is switched from the current transformer 65 to the current transformer 66.
Therefore, for example, an additional circuit for switching the relay contact 64a according to the detection result of the disconnection detection unit is not required, and the acquisition destination of the signal is switched from the current transformer 66 to the current transformer 65 by the relay contact 64a (that is, switching is performed). It is possible to arbitrarily set a condition for returning.

Furthermore, according to the first embodiment, an H bridge in which diodes (commutation diodes) D1, D2, D3, and D4 are connected in parallel to switches (switching elements) Q1, Q2, Q3, and Q4 included in each arm. The inverter 3 using (full bridge) converts the DC power and the AC power bidirectionally.
Therefore, when the AC voltage applied from the power generation device 8 is higher than the AC voltage that the inverter 3 intends to output when converting DC power to AC power, the AC power from the power generation device 8 is used. The diodes D1, D2, D3, and D4 can be rectified and converted to DC power, and the EV (power storage device) 4 can be charged with the converted DC power.

(Embodiment 2)
In the first embodiment, when a part of the AC power from the power generation device 8 becomes surplus power, the storage battery 41 is charged without limitation by the surplus power, while the second embodiment is different from the storage battery 41. This is a mode in which AC power from the power generation device 8 is cut off when there is no room to accept charging power.

  The configuration of the power supply system in the second embodiment, the flow of power supply at the time of non-power failure and at the time of power failure, the configuration of the inverter 3, and the processing procedure of the CPU 11 that controls the switching from the grid operation to the independent operation in the power conversion device 1 Since each of them is the same as that shown in FIGS. 1 to 5, the same reference numerals are given to the portions corresponding to the first embodiment, and the description and explanation of these drawings are omitted.

Below, the procedure which interrupts | blocks the alternating current power from the electric power generating apparatus 8 during the independent operation of the power converter device 1 is demonstrated using a flowchart.
FIG. 6 is a flowchart showing a processing procedure of the CPU 11 for switching on / off of the relay contact (changeover switch) 64a in the power conversion device 1 according to the second embodiment of the present invention. The process of FIG. 6 is started at a constant cycle (for example, every second) during the autonomous operation of the power conversion device 1.

  When the process of FIG. 6 is activated, the CPU 11 acquires the SOC of the storage battery 41 of the EV 4 using the CAN communication unit 15 (S22: equivalent to an acquisition unit), and is set in step S16 of the process of FIG. It is determined whether or not the switching flag is on (S23). When the switching flag is on (S23: YES), that is, when the COM terminal of the relay contact 64a is connected to the NO terminal, the CPU 11 determines whether or not the SOC acquired in step S22 is greater than 99%, for example. (S24: equivalent to means for determining whether or not the SOC is greater than a predetermined threshold). If not (S24: NO), the process of FIG. 6 is terminated without executing any special process.

  When the obtained SOC is larger than 99% (S24: YES), that is, when the storage battery 41 has no room for accepting the charging power, the CPU 11 turns off the relay contact (changeover switch) 64a by the relay drive circuit 24 and sets the COM terminal. Is connected to the NC terminal (S25: corresponding to the second switching means), the switching flag is set to OFF (S26), and the processing of FIG.

  By switching so that the COM terminal is connected to the NC terminal in step S25, the control unit 83 of the power generation device 8 controls the power generation by the power generation unit 81 based on the signal indicating the current detection result by the current transformer 65. . However, in this case, the disconnection relay 55 is in an off state, and the current flowing through the bus 50 to which the current transformer 65 is coupled does not become a current opposite to the reverse power flow. The part 81 is stopped. Thereafter, since the power conversion device 1 converts the DC power from the EV4 storage battery 41 into AC power and supplies it to the loads 61 and 62, the storage battery 41 is discharged over time and the SOC decreases.

  When the switching flag is not on in step S23 (S23: NO), that is, when the COM terminal of the relay contact 64a is not connected to the NO terminal and the power generation device 8 has already stopped, the CPU 11 performs step S22. It is determined whether or not the SOC acquired in step S1 has decreased to 90% or less, that is, whether or not the discharge has progressed until there is room for the storage battery 41 to accept the charging power (S27: whether or not it is equal to or less than a second threshold value). Equivalent to means for determining). When the SOC is not 90% or less (S27: NO), the CPU 11 ends the process of FIG. 6 with the relay contact 64a turned off.

  On the other hand, when the SOC is 90% or less (S27: YES), the CPU 11 drives the relay contact (switch) 64a to be turned on by the relay drive circuit 24 so that the COM terminal is connected to the NO terminal (S28). : Equivalent to the means for switching to the second detection unit) and the switching flag is set to ON (S29), and the processing of FIG. Thereby, the electric power generating apparatus 8 returns to the state which can perform the interconnection | linkage operation | movement linked to the self-sustained operation of the power converter device 1, as demonstrated using FIG.

As described above, according to the second embodiment, the power conversion device 1 drives the relay contact (changeover switch) 64a to turn on, and the acquisition source of the signal viewed from the power generation device 8 is changed from the current transformer 65 to the current transformer 66. When the SOC of the storage battery 41 included in the EV 4 becomes larger than a predetermined threshold due to the continued charging of the EV 4 after switching to the power conversion device 1, the power conversion device 1 turns off the relay contact 64 a and acquires the above signal Is switched from the current transformer 66 to the current transformer 65.
In this case, the current transformer 65 does not detect a current in the opposite direction to the reverse power flow, and it is not guaranteed that no reverse power flow will occur, so the power generation device 8 stops power generation. Therefore, it is possible to stop excessive charging of the EV4.

Further, according to the second embodiment, after the power conversion device 1 turns off the relay contact (switch) 64a and switches the acquisition source of the signal viewed from the power generation device 8 from the current transformer 66 to the current transformer 65, When the obtained SOC of the storage battery 41 becomes equal to or smaller than the second threshold value smaller than the predetermined threshold value, the power conversion device 1 switches the acquisition source of the signal from the current transformer 65 to the current transformer 66.
Therefore, when the discharge progresses until EV 4 can accept the charge, the power generation device 8 restarts the power generation based on the detection result of the current transformer 66 in which the current in the direction opposite to the reverse flow is detected. Is possible.

  In the second embodiment, the relay contact 64a is switched from on to off in order to cut off the AC power from the power generation device 8, but the AC power output by the power conversion device 1 in the self-sustaining operation is switched. The target voltage or the target frequency may be changed. Specifically, the target voltage or the target frequency is changed so that the voltage or frequency of the AC power output from the power conversion device 1 becomes a voltage or a frequency at which the grid connection protection function is exhibited in the power generation device 8.

(Embodiment 3)
In the first embodiment, when the system is disconnected from the power system 7, the power converter 1 switches the relay contact (switch) 64a, whereas in the third embodiment, the power system 7 In the case of a power failure, an additional circuit not included in the power conversion device 1 disconnects the system and switches the relay contact 64a.

Since the flow of power supply at the time of non-power failure and power failure in the third embodiment and the configuration of the inverter 3 are the same as those shown in FIGS. 2 to 4, the same reference numerals are given to the portions corresponding to the first embodiment. The description and explanation of these figures will be omitted.
FIG. 7 is a block diagram illustrating a configuration example of the power supply system according to Embodiment 3 of the present invention.

  The main breaker 56 has an auxiliary contact 561 that outputs a contact signal indicating the open / closed state of the main breaker 56. One end of the auxiliary contact 561 is connected to the electric circuit between the main breaker 56 and the relay contact 55 a, and the other end is connected to the drive coil 55 c of the disconnecting relay 55.

  The disconnection relay 55 has a second auxiliary contact 552 that is turned on / off together with the relay contact 55a. One end of the second auxiliary contact 552 is connected to the electric circuit between the main breaker 56 and the relay contact 55 a, and the other end is connected to the drive coil 64 c of the relay 64. Both ends of the auxiliary contact 551 are connected to a relay monitoring circuit 28 that monitors the on / off state of the disconnecting relay 55.

  The current transformer 66 is connected to an NC terminal of a relay contact 64 (corresponding to a changeover switch) 64a of the relay 64. The current transformer 65 is connected to the NO terminal of the relay contact 64a. That is, in the configuration of the third embodiment, it should be noted that the connection destination of the NC terminal and the NO terminal of the relay contact 64a is reversed as compared with the configuration shown in FIG. 1 of the first embodiment. .

The relay monitoring circuit 28 is connected to the I / O port 16.
In addition, the same code | symbol is attached | subjected to the location corresponding to FIG. 1 of Embodiment 1, and the description is abbreviate | omitted.

  In the above configuration, when the main circuit breaker 56 of the distribution board 5 is turned on and the power system 7 is not out of power, the auxiliary contact 561 is turned on, whereby the power system is connected via the main circuit breaker 56 and the auxiliary contact 561. 7 is applied to the drive coil 55c, and the disconnect relay 55 is turned on. Further, when the second auxiliary contact 552 is turned on, the AC voltage of the power system 7 is applied to the drive coil 64c via the main breaker 56 and the second auxiliary contact 552, and the relay contact 64a is driven on. The

  In this case, since the COM terminal is connected to the NO terminal, the power generation device 8 generates power when the current flowing through the bus 50 to which the current transformer 65 is coupled becomes the current toward the loads 61 and 62. This state is substantially the same as the state shown in FIG. 2 of the first embodiment, and the operation of power conversion device 1 is the same as that of the first embodiment.

  Next, when the power system 7 fails, or when the main breaker 56 is manually opened, the AC voltage is not applied to the drive coil 55c via the auxiliary contact 561, and the disconnecting relay 55 is turned off. Further, when the second auxiliary contact 552 is turned off, the AC voltage is not applied to the drive coil 64c via the main breaker 56 and the second auxiliary contact 552, and the relay contact 64a is turned off. In this case, since the COM terminal is connected to the NC terminal, the power generation device 8 continues power generation when the current flowing through the bus 50 to which the current transformer 66 is coupled becomes the current toward the loads 61 and 62.

  One power conversion device 1 determines whether or not a disconnection from the power system 7 has been detected before the power system 7 fails or before the main breaker 56 is manually opened. If the disconnection is detected, the autonomous operation is started. In this case, the CPU 11 executes steps S14, S17, and S18 shown in FIG. 5 of the first embodiment (not shown). The state where the power conversion device 1 starts the self-sustained operation is substantially the same as the state shown in FIG. 3 of the first embodiment.

  As described above, according to the third embodiment, the power conversion device 1 detects a power failure (including the opening of the main breaker 56) and power recovery of the power system 7, and controls the disconnection relay 55 to be turned off and on. Except that the relay contact 64a is not switched, the operation of the system is the same as that of the first embodiment, so that the same effect as that of the first embodiment is obtained.

(Embodiment 4)
The first embodiment is a mode including one power generation device 8, whereas the fourth embodiment is a mode including a solar power generation device 9 in addition to the power generation device 8.
The configuration of the power supply system excluding the solar power generation device 9 according to the fourth embodiment, the configuration of the inverter 3, and the processing procedure of the CPU 11 that controls the switching from the interconnection operation to the independent operation by the power conversion device 1 are illustrated in FIG. Since it is the same as that shown in 1, 4 and 5, the same reference numerals are given to the portions corresponding to the first embodiment, and the description and explanation of these figures are omitted.

  FIG. 8 is an explanatory diagram showing the flow of power supply during a non-power failure of the power supply system according to Embodiment 4 of the present invention, and FIG. 9 is during a power failure of the power supply system according to Embodiment 4 of the present invention. It is explanatory drawing which shows the flow of electric power feeding. 8 and 9, the flow of AC power from the power system 7 is indicated by black arrows, and the flow of AC power from the power generation device 8 and the solar power generation device 9 is indicated by white arrows and white arrows with parentheses. Furthermore, the flow of AC power from the power converter 1 is indicated by a black arrow with parentheses.

  In FIG. 8, the solar power generation device 9 performs an interconnection operation linked to the electric power system 7. When the power conversion device 1 stops conversion, AC power from the power generation device 8 and the solar power generation device 9 (hereinafter referred to as AC power consumed by the loads 61 and 62 including the electric devices) When only the sum of the generated power is insufficient, the shortage of AC power is supplied from the power system 7.

  When the power converter 1 converts AC power from the bus 50 into DC power and charges the storage battery 41, when the sum of generated power is less than the sum of power consumption and power flowing into the power converter 1, white The sum of the generated power indicated by the open arrows and the white arrows with parentheses is diverted into the power converter 1 and the loads 61 and 62, and insufficient AC power is supplied from the power system 7.

  When the sum of the generated power is greater than at least the power consumption, a little more power than the surplus power obtained by subtracting the power consumption from the sum of the generated power is converted into DC power by the power conversion device 1 and charged to the storage battery 41. It is preferable to control as described above.

  On the other hand, when the power conversion device 1 converts the DC power from the storage battery 41 into AC power and supplies it to the loads 61 and 62, it is a major premise that the sum of the generated power does not exceed the power consumption. Furthermore, it is necessary to perform control so that less AC power than power obtained by subtracting the sum of generated power from power consumption is supplied from the power converter 1. When controlled in this way, the loads 61 and 62 have a sum of generated power indicated by a white arrow and a white arrow with parentheses, AC power from the power system 7 indicated by a black arrow, and parentheses. AC power from the power converter 1 indicated by the black arrow flows.

  Moving to FIG. 9, when the power system 7 fails or when the main breaker 56 is manually opened, the power conversion device 1 switches the inverter 3 to the independent operation. The power generator 8 and the solar power generator 9 continue the operation by performing the interconnection operation linked to the independent operation of the power conversion device 1. In this case, only the AC power indicated by the white arrow and the white arrow with parentheses supplied to the loads 61 and 62 by the power generator 8 and the solar power generator 9 via the bus 50 is consumed by the loads 61 and 62. While the power consumption is insufficient, the insufficient power is supplied from the power converter 1 to the loads 61 and 62.

  On the other hand, when the sum of the AC power that the power generator 8 and the solar power generator 9 should supply to the loads 61 and 62 via the bus 50 exceeds the power consumed by the loads 61 and 62, the surplus power is It is converted into direct current power by the power conversion device 1 and directed to charging the storage battery 41. Thereby, since the voltage rise of bus 50 is suppressed, the alternating voltage of bus 50 is maintained at the above-mentioned reference voltage.

As described above, according to the fourth embodiment, the solar power generation device 9 that generates power using sunlight is connected to the power line between the current transformer 65 and the relay contact 55a of the disconnection relay 55.
Thereby, since the generated power of the solar power generation device 9 is supplied to the power conversion device 1 and the loads 61 and 62, surplus power that is not consumed by the loads 61 and 62 is temporarily converted into DC power by the power conversion device 1. EV4 is charged. Therefore, it is possible to continue the independent operation for a longer time than in the case where the solar power generation device 9 is not provided.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. In addition, the technical features described in each embodiment can be combined with each other.

DESCRIPTION OF SYMBOLS 1 Power converter 10 Control part 11 CPU
12 ROM
13 RAM
15 CAN communication unit 25 Relay drive monitoring circuit 28 Relay monitoring circuit 3 Inverter D1, D2, D3, D4 Commutation diode Q1, Q2, Q3, Q4 Switch 4 EV
41 storage battery 5 distribution board 50 bus 55 disconnection relay 55a relay contact 551 auxiliary contact 552 second auxiliary contact 56 main breaker 561 auxiliary contact 61, 62 load 64a relay contact 65, 66 current transformer 7 power system 8 power generator 81 power generation Part 9 Solar power generator

Claims (8)

A detection unit that detects a current flowing in a power line for supplying power to the load from the power system and outputs a signal indicating a detection result, and is connected to the power line between the detection unit and the load, and is acquired from the detection unit A generator that controls the generated power based on the generated signal and the power line between the power generator and the load, and bidirectionally AC / DC converts AC power from the power line and DC power from the power storage device. In a power supply system comprising a power conversion device,
A second detector that detects a current flowing through the power line between the power converter and a load and outputs a second signal according to a detection result;
A changeover switch that switches the acquisition source of the signal acquired by the power generation device to either the detection unit or the second detection unit;
The power conversion device is configured to be capable of independent operation in which direct current power from the power storage device is converted into alternating current power and supplied to the load.
When the power conversion device performs a self-sustained operation, the signal acquisition destination is switched to the second detection unit by the changeover switch. The power conversion device charges the power storage device with DC power obtained by AC / DC conversion of AC power from the power generation device when the AC voltage from the power generation device exceeds a reference voltage to be output in the independent operation. The power supply system according to claim 1, wherein the power supply system is provided. A disconnection detector for detecting disconnection from the power system;
Power supply system according to claim 1 or 2, characterized in that said power converter, said disconnection detecting unit are to perform the autonomous operation if it detects a disconnection. 4. The power converter according to claim 3, further comprising: a switching unit configured to switch the acquisition source of the signal to the second detection unit by the changeover switch when the disconnection detection unit detects a disconnection. 5. The power supply system described. The power converter is
An acquisition means for acquiring the SOC of the storage battery included in the power storage device when the switching means is switched to the second detection unit;
Means for determining whether or not the SOC acquired by the acquisition means is greater than a predetermined threshold;
5. The power supply system according to claim 4, further comprising: a second switching unit configured to switch the acquisition source of the signal to the detection unit by the switch when the unit is determined to be large. The power converter is
Means for determining whether or not the SOC acquired by the acquisition means is equal to or smaller than a second threshold value smaller than the predetermined threshold when the second switching means is switched to the detection unit;
The power supply system according to claim 5, further comprising: a unit that switches the acquisition source of the signal to the second detection unit by the switch when the unit determines that the following is the following.   The power conversion device includes an H bridge circuit in which a parasitic diode or a commutation diode is connected in parallel to a switching element included in each arm, and includes an inverter that bidirectionally converts DC power and AC power. The power supply system according to claim 1, wherein the power supply system is a power supply system.   The power supply according to any one of claims 1 to 7, further comprising a solar power generation device that is connected to the power line between the detection unit and a power system and generates power using sunlight. system.

Images