JP6119332B2 - Inverter and program - Google Patents

Description

  The present invention relates to a power conditioner and a program.

In Patent Document 1, the maximum power estimated value of the solar cell module estimated based on the input power input to the converter and the voltage accumulated in the capacitor is compared with the activation determination value, and the power conditioner is based on the comparison result. A photovoltaic power generation system that determines whether or not to start the system is disclosed.
Japanese Patent Application Laid-Open No. 2009-247184

  In recent years, the types of solar cell modules connected to the power conditioner have increased, and solar cell modules having various specifications may be connected to the power conditioner. In connection with this, the precision which estimates the electric power of a solar cell module falls, and the precision of determination of the decision | availability of starting of a power conditioner may fall. Therefore, it is desired to improve the accuracy of determining whether or not the inverter can be activated.

  A power conditioner according to an aspect of the present invention includes a booster circuit that boosts a voltage from a power supply, an inverter that converts direct current output from the booster circuit into alternating current, and outputs the alternating current to a load or a system power supply, and the inverter and the system power supply Alternatively, a shut-off unit that switches whether or not to electrically shut off the load, a control unit that controls the operation of the inverter, and a shut-off in response to the voltage output from the power supply becoming higher than the reference voltage Start determination that determines whether or not startable power can be obtained from the power supply by operating the booster circuit and the inverter with the control section in a state where the inverter and the system power supply or load are electrically disconnected via the control section And an activation determination unit that determines that startable electric power can be obtained from the power source. And a control unit.

  In the power conditioner, when the voltage output from the booster circuit is lower than the upper limit voltage higher than the reference voltage, the start determination unit electrically disconnects the inverter from the system power supply or the load via the cutoff unit Thus, the control unit may operate the inverter and the booster circuit to determine whether or not startable power can be obtained from the power source.

  In the power conditioner, the start determination unit can obtain startable power from the power supply when the voltage output from the booster circuit when the power output from the booster circuit reaches the reference power is equal to or higher than the startable voltage. May be determined.

  A program according to one embodiment of the present invention includes a booster circuit that boosts a voltage from a power supply, an inverter that converts direct current output from the booster circuit into alternating current, and outputs the alternating current to a load or a system power supply, and an inverter and the system power supply or load A program for causing a computer to function as a control device for determining whether or not to start a power conditioner, which includes a shut-off unit that switches whether or not to electrically shut off between the booster circuit and the operation of the booster circuit In response to the voltage output from the power source being equal to or higher than the reference voltage, the control unit is electrically disconnected between the inverter and the system power source or the load via the cutoff unit. A start determination unit that determines whether or not startable power can be obtained from the power source by operating the inverter, and the start determination unit obtains startable power from the power source. In response to determining that that, as the cutoff controller for electrically connecting between the inverter and the load or system power supply via a blocking unit, causes the computer to function.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 is a system configuration diagram illustrating an example of an overall configuration of a solar cell system according to an embodiment. It is a flowchart which shows an example of the procedure of the starting process performed by a control apparatus. It is a figure which shows an example of the functional block of the control apparatus which concerns on this embodiment. It is a flowchart which shows the procedure in which a control apparatus performs the starting determination of a power conditioner.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a system configuration diagram showing an example of the overall configuration of the solar cell system according to the present embodiment. The solar cell system includes a solar cell array 200 and a power conditioner 10. In the solar cell array 200, a plurality of solar cell strings in which a plurality of solar cell modules are connected in series are connected in parallel. The plurality of solar cell arrays 200 is an example of a power source that outputs a DC voltage.

  The power conditioner 10 boosts the DC voltage output from the solar cell array 200, converts the boosted DC voltage into an AC voltage, and outputs the AC voltage to the system power supply 300 side. The power conditioner 10 includes a capacitor C1, a booster circuit 20, a capacitor C2, an inverter 40, a coil L2, a capacitor C3, a relay 50, a power supply 60, and a control device 100.

  One end and the other end of the capacitor C <b> 1 are electrically connected to the positive terminal and the negative terminal of the solar cell array 200 to smooth the DC voltage output from the solar cell array 200. The booster circuit 20 includes a coil L1, a switch Tr, and a diode D1. The booster circuit 20 may be a so-called chopper type switching regulator. The booster circuit 20 boosts the voltage from the solar cell array 200.

  The switch Tr may be, for example, an insulated gate bipolar transistor (IGBT). One end of the coil L1 is connected to one end of the capacitor C1, and the other end of the coil L1 is connected to the collector of the switch Tr. The collector of the switch Tr is connected to the anode of the diode D1, and the emitter of the switch Tr is connected to the other end of the capacitor C1. The coil L1 accumulates energy based on the electric power from the solar cell array 200 while the switch Tr is on, and releases the energy accumulated while the switch Tr is off. As a result, the booster circuit 20 boosts the DC voltage from the solar cell array 200. The diode D1 rectifies the output from the coil L1. The diode D1 prevents the boosted DC voltage from flowing from the output side of the booster circuit 20 to the input side.

  Note that the booster circuit 20 is not limited to the above-described configuration, and may be configured by, for example, an insulating booster circuit having a transformer winding such as a half-bridge booster circuit or a full-bridge booster circuit.

  Capacitor C2 smoothes the DC voltage output from booster circuit 20. The inverter 40 includes a switch. When the switch is turned on / off, the inverter 40 converts the DC voltage output from the booster circuit 20 into an AC voltage and outputs the AC voltage to the system power supply 300 or the load 310. The inverter 40 may be constituted by, for example, a single-phase full-bridge PWM inverter that includes four semiconductor switches that are bridge-connected. Of the four semiconductor switches, one pair of semiconductor switches is connected in series. Of the four semiconductor switches, the other pair of semiconductor switches are connected in series and connected in parallel with the one pair of semiconductor switches.

  A coil L2 and a capacitor C3 are provided between the inverter 40 and the system power supply 300. The coil L2 and the capacitor C3 remove noise from the AC voltage output from the inverter 40. A relay 50 is provided between the capacitor C3 and the system power supply 300. Relay 50 switches whether to electrically disconnect between inverter 40 and system power supply 300 or load 310. When the relay 50 is turned on, the power conditioner 10 and the system power supply 300 or the load 310 are electrically connected. When the relay 50 is turned off, the power conditioner 10 and the system power supply 300 or the load 310 are electrically disconnected. . The relay 50 is an example of a blocking unit.

  The power supply 60 is constituted by, for example, a power supply IC chip. The supply power source 60 is connected to the output side of the booster circuit 20, generates electric power indicating a predetermined voltage supplied to the control device 100 from a DC voltage extracted from the booster circuit 20, and uses the generated electric power to the control device. 100. The power supply 60 is activated when the output voltage from the booster circuit 20 reaches the reference voltage when the switch Tr of the booster circuit 20 is in the OFF state. After the start-up, the supply power supply 60 generates drive power for driving the control device 100 using the power output from the booster circuit 20 and supplies the drive power to the control device 100. The power supply 60 may generate power to be supplied to the control device 100 by directly using power from the system power supply 300.

  The control device 100 controls the switching operation of the booster circuit 20 so as to obtain the maximum power from the solar cell array 200, boosts the DC voltage output from the solar cell array 200, and converts the boosted DC voltage to AC. The voltage is converted and output to the system power supply 300 side.

  The power conditioner 10 further includes voltage sensors 12 and 16 and current sensors 14 and 18. The voltage sensor 12 detects a voltage Vin corresponding to a potential difference between both ends of the solar cell array 200. The voltage sensor 16 detects a voltage Vout corresponding to a potential difference between both ends on the output side of the booster circuit 20. The current sensor 14 detects a current Iin output from the solar cell array 200 and flowing to the input side of the booster circuit 20. The current sensor 18 detects the current Iout output from the booster circuit 20.

  FIG. 2 is a flowchart illustrating an example of a processing procedure executed when the control device 100 is activated.

  Corresponding to the fact that the output voltage Vout input from the solar cell array 200 and output from the booster circuit 20 becomes equal to or higher than the reference voltage Vth1 when the booster circuit 20, the inverter 40, the supply power source 60, and the control device 100 are stopped. (S10), the power supply 60 is activated. The power supply 60 generates driving power for driving the control device 100 using the power from the solar cell array 200. The control device 100 receives power from the power supply 60 and starts up (S12).

  The control device 100 starts the operation of the booster circuit 20 in a state where the inverter 40 and the system power supply 300 or the load 310 are electrically disconnected via the relay 50 (S14). The control device 100 estimates the power Wa that can be output from the booster circuit 20 using, as a parameter, the amount of change in the power output from the booster circuit 20 when the input voltage input to the booster circuit 20 is changed (S16). ).

  Next, the control device 100 determines whether or not the power Wa is equal to or higher than the power Wt necessary to operate the control device 100, the booster circuit 20, and the inverter 40 (S18). When the voltage Wa is smaller than the power Wt, the control device 100 determines that the power obtained from the solar cell array 200 does not satisfy the power necessary for starting the power conditioner 10, and the control device 100 The operation is stopped (S20), and when a predetermined standby period elapses (S22), the operation of the booster circuit 20 is started again.

  On the other hand, when it is determined that the estimated power Wa is equal to or greater than the power Wt, the control device 100 turns on the relay 50 (S24), starts the operation of the inverter 40, and establishes the grid connection with the grid power supply 300. Start (S26).

  According to the above processing procedure, the control device 100 determines that the estimated power satisfies the power that can operate the control device 100, the booster circuit 20, and the inverter 40. And the inverter 40 is operated. In this case, if the accuracy of the estimated power is insufficient, the actual power obtained from the solar cell array may be insufficient, and the inverter 40 may not be operated by the power obtained from the solar cell array. In this case, after the process of step S26, control device 100 stops the operation of booster circuit 20 and inverter 40 and temporarily turns off relay 50. Then, the control device 100 starts the operation of the booster circuit 20 again and performs power estimation again. That is, when the power conditioner 10 is activated, the relay 50 may be repeatedly turned on and off by repeatedly estimating the power. Moreover, since the electric power obtained may change with the kind of solar cell array connected to the power conditioner 10, if there are many kinds of solar cell arrays connectable to the power conditioner 10, the control apparatus 100 will be accurate. It becomes even more difficult to estimate power.

  Therefore, according to the present embodiment, when the control device 100 operates the inverter 40 in addition to the booster circuit 20 with the relay 50 turned off, based on the electric power output from the booster circuit 20, It is determined whether or not startable power corresponding to the minimum power required to start the power conditioner 10 is obtained from the solar cell array 200. Thereby, the precision of the starting determination of the power conditioner 10 can be improved. Further, when the power conditioner 10 is activated, it is possible to prevent the relay 50 from being repeatedly turned on and off by repeatedly estimating the power. Therefore, it is possible to reduce the frequency of the generation of the operation sound that occurs when the relay 50 is turned on / off. Further, the progress of the deterioration of the relay 50 accompanying the ON / OFF of the relay 50 can be suppressed.

  FIG. 3 shows an example of functional blocks of the control device 100 according to the present embodiment. The control device 100 includes a control unit 102, a relay control unit 104, and an activation determination unit 106. Control unit 102 controls operations of booster circuit 20 and inverter 40. The control unit 102 controls the step-up ratio by turning on and off the switch Tr provided in the step-up circuit 20 based on the PWM control, so that the maximum or maximum power can be obtained from the solar cell array 200. The voltage Vin is controlled. The control unit 102 controls the input voltage of the inverter 40 by turning on and off each switch included in the inverter 40 based on PWM control, and the alternating current obtained by synchronizing the direct current output from the booster circuit 20 with the voltage of the system power supply 300. Convert to

  Relay control unit 104 electrically connects or disconnects between inverter 40 and system power supply 300 or load 310 by turning relay 50 on and off. The activation determination unit 106 electrically connects the inverter 40 and the system power supply 300 or the load 310 via the relay 50 in response to the voltage output from the solar cell array 200 being equal to or higher than the reference voltage Vth1. In the shut-off state, the booster circuit 20 and the inverter 40 are operated by the control unit 102.

  In addition, activation determination unit 106 determines whether or not startable power can be obtained from solar cell array 200 in a state where booster circuit 20 and inverter 40 are operating. The activation determination unit 106 determines that the power that can be activated from the solar cell array 200 is the voltage that is output from the voltage booster circuit 20 when the power output from the voltage booster circuit 20 reaches the reference power Wth is equal to or higher than the voltage Vth3 that can be activated. You may determine with obtaining (step S110 of FIG. 3).

  The purpose of causing the control unit 102 to operate the inverter 40 with the relay 50 turned off is that the activation determination unit 106 is necessary to activate the inverter 40 in addition to the control device 100 and the booster circuit 20 from the solar cell array 200. The purpose is to more accurately determine whether or not electric power can be obtained. Therefore, the control unit 102 may operate each inverter 40 by controlling each switch of the inverter 40 under an arbitrary condition. For example, the control unit 102 may operate the inverter 40 by controlling each switch of the inverter 40 with a duty ratio of 50%. By controlling each switch of the inverter 40 with a duty ratio of 50%, the processing burden on the control device 100 can be reduced.

  The relay control unit 104 electrically connects between the inverter 40 and the system power supply 300 or the load 310 via the relay 50 in response to the start determination unit 106 determining that startable power can be obtained from the solar cell array 200. Connect.

  Here, if the voltage output from the solar cell array 200 is high, the voltage output from the booster circuit 20 may be too high when the booster circuit 20 is operated. In this case, an element such as the capacitor C2 provided on the output side of the booster circuit 20 may be adversely affected.

  Therefore, when the voltage output from the booster circuit 20 is equal to or higher than the upper limit voltage Vth2 higher than the reference voltage Vth1 in a state where the booster operation of the booster circuit 20 is stopped, the activation determination unit 106 is connected to the inverter 40 via the relay 50. The control unit 102 may operate the inverter 40 in a state where the system power supply 300 or the load 310 is electrically disconnected (Step 104 and Step S108 in FIG. 3). Then, the start determination unit 106 determines whether or not startable power can be obtained from the solar cell array 200 in a state where the boost operation of the boost circuit 20 is stopped and the switch of the inverter 40 is turned on / off. It is also possible (step S110 in FIG. 3). That is, when the voltage output from the booster circuit 20 is equal to or higher than the upper limit voltage Vth2 that is higher than the reference voltage Vth1, the activation determination unit 106 stops the booster operation of the booster circuit 20 and performs only the on / off operation of the switch of the inverter 40. Thus, it may be determined whether or not startable power is obtained from the solar cell array 200.

  FIG. 4 is a flowchart illustrating a procedure in which the control device 100 performs the activation determination of the power conditioner 10.

  Corresponding to the fact that the output voltage Vout input from the solar cell array 200 and output from the booster circuit 20 becomes equal to or higher than the reference voltage Vth1 when the booster circuit 20, the inverter 40, the supply power source 60, and the control device 100 are stopped. Thus, the power supply 60 is activated. The power supply 60 generates driving power for driving the control device 100 using the power from the solar cell array 200. The control device 100 receives power from the power supply 60 and starts up (S102).

  When the control device 100 is activated, the activation determining unit 106 determines whether or not the output voltage Vout of the booster circuit 20 is equal to or higher than the upper limit voltage Vth2 (S104). When the output voltage Vout is smaller than the upper limit voltage Vth2, the activation determination unit 106 is electrically connected between the inverter 40 and the system power supply 300 or the load 310 via the relay 50, and the control unit 102 causes the boost circuit 20 to be disconnected. Then, the operation of the inverter 40 is started (S106). The control unit 102 may start an on / off operation of each switch included in the booster circuit 20 and the inverter 40.

  Next, activation determination unit 106 calculates electric power Wout output from booster circuit 20 based on voltage Vout and current Iout output from booster circuit 20. Activation determination unit 106 determines whether or not output voltage Vout of the booster circuit when electric power Wout reaches reference electric power Wth is equal to or higher than activation possible voltage Vth3 (S110). When the output voltage Vout is equal to or higher than the startable voltage Vth3, the start determination unit 106 determines that startable power is obtained from the solar cell array 200, and the control unit 102 temporarily stops the operation of the inverter 40 ( (S112), the relay control unit 104 turns on the relay 50 (S114). After the relay control unit 104 turns on the relay 50, the control unit 102 starts the operation of the inverter 40 again (S116). Note that, when the power conditioner 10 is not linked to the system power supply 300, the control unit 102 does not have to temporarily stop the inverter 40 before turning on the relay 50.

  On the other hand, when the output voltage Vout is equal to or higher than the upper limit voltage Vth2, the activation determination unit 106 is in a state where the inverter 40 and the system power supply 300 or the load 310 are electrically disconnected via the relay 50, and In a state where 20 is stopped, the control unit 102 starts the operation of the inverter 40 (S108). Next, activation determination unit 106 determines whether or not output voltage Vout of the booster circuit when electric power Wout reaches reference electric power Wth is equal to or higher than activation possible voltage Vth3 (S110).

  When the output voltage Vout is smaller than the startable voltage Vth3, the start determination unit 106 temporarily stops the operation of the booster circuit 20 and the inverter 40 or the operation of the inverter 40 by the control unit 102 (S118). If a predetermined waiting period has elapsed after the stop (S120), the activation determination unit 106 executes the processes subsequent to step S104 again.

  As described above, according to the present embodiment, when the power conditioner 10 performs the activation determination, the power output from the solar cell array 200 is estimated while the inverter 40 is operated, and the estimated power The activation can be determined from Therefore, the activation determination can be performed with higher accuracy regardless of the type of the solar cell array 200 connected to the power conditioner 10. Therefore, when the power conditioner 10 is activated, it is possible to prevent the relay 50 from being repeatedly turned on and off by repeatedly estimating the power. Moreover, the frequency of the operation sound generated when the relay 50 is turned on and off can be reduced, and the progress of deterioration of the relay 50 caused when the relay 50 is turned on and off can be suppressed.

  In addition, each part with which the control apparatus 100 which concerns on this embodiment is provided installs the program recorded on the computer-readable recording medium which performs various processes regarding the starting determination of the power conditioner 10, and makes this computer run this program It may be configured. In other words, the control device 100 may be configured by causing a computer to function as each unit included in the control device 100 by causing the computer to execute programs that perform various processes relating to the activation determination of the power conditioner 10.

  The computer has various memories such as a CPU, ROM, RAM, and EEPROM (registered trademark), a communication bus, and an interface. The CPU reads and sequentially executes a processing program stored in the ROM as firmware in advance, and thereby the control device 100. Function as.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Power conditioner 20 Booster circuit 40 Inverter 50 Relay 60 Supply power supply 100 Control apparatus 102 Control part 104 Relay control part 106 Starting determination part 200 Solar cell array 300 System power supply 310 Load

Claims (6)

A booster circuit for boosting the voltage from the power supply;
An inverter that converts direct current output from the booster circuit into alternating current and outputs the load to a system power supply;
A shut-off unit that switches whether to electrically shut off between the inverter and the system power supply or the load;
A control unit for controlling operations of the booster circuit and the inverter;
In response to the voltage output from the power source being equal to or higher than a reference voltage, the control unit is electrically disconnected between the inverter and the system power source or the load via the cutoff unit. And a start determination unit that determines whether or not startable power can be obtained from the power source by operating the inverter.
In response to determining that the startable power can be obtained from the power source by the start determination unit, a disconnection control for electrically connecting the inverter and the load or the system power supply via the disconnection unit And a power conditioner.   When the voltage output from the booster circuit is smaller than the upper limit voltage higher than the reference voltage, the start determination unit electrically cuts off the inverter and the system power supply or the load via the cut-off unit. 2. The power conditioner according to claim 1, wherein in the state, the control unit operates the inverter and the booster circuit to determine whether or not startable power can be obtained from the power source. When the voltage output from the booster circuit is equal to or higher than the upper limit voltage, the activation determination unit is in a state where the inverter and the system power supply or the load are electrically disconnected via the interruption unit, and The power conditioner according to claim 2, wherein the inverter is operated by the control unit in a state where the booster circuit is stopped, and it is determined whether or not startable power can be obtained from the power source. The start determination unit obtains the startable power from the power supply when the voltage output from the booster circuit when the power output from the booster circuit reaches a reference power is equal to or higher than the startable voltage. The power conditioner as described in any one of Claim 1 to 3 which determines . The start determination unit operates the inverter by controlling each switch of the inverter to a duty ratio of 50% by the control unit, and determines whether startable power can be obtained from the power source. The power conditioner according to any one of 1 to 4. A booster circuit that boosts a voltage from a power supply, an inverter that converts direct current output from the booster circuit into alternating current and outputs the alternating current to a load or a system power supply, and an electrical connection between the inverter and the system power supply or the load A program for causing a computer to function as a control device for determining whether or not to start a power conditioner including a shut-off unit that switches whether or not to shut down
A control unit for controlling operations of the booster circuit and the inverter;
In response to the voltage output from the power source being equal to or higher than a reference voltage, the control unit is electrically disconnected between the inverter and the system power source or the load via the cutoff unit. And a start determination unit that determines whether or not startable power can be obtained from the power source by operating the inverter.
In response to determining that the startable power can be obtained from the power source by the start determination unit, a disconnection control for electrically connecting the inverter and the load or the system power supply via the disconnection unit A program for causing the computer to function as a unit.

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