JP3796460B2 - Power conditioner for photovoltaic system - Google Patents

Power conditioner for photovoltaic system Download PDF

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Publication number
JP3796460B2
JP3796460B2 JP2002091886A JP2002091886A JP3796460B2 JP 3796460 B2 JP3796460 B2 JP 3796460B2 JP 2002091886 A JP2002091886 A JP 2002091886A JP 2002091886 A JP2002091886 A JP 2002091886A JP 3796460 B2 JP3796460 B2 JP 3796460B2
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Japan
Prior art keywords
power
voltage
solar cell
unit
inverter
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Expired - Fee Related
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JP2002091886A
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JP2003289626A (en
Inventor
司 竹林
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シャープ株式会社
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power conditioner for a photovoltaic power generation system, and more particularly to a power conditioner that receives electric power from a solar cell and converts it into AC power.
[0002]
[Prior art]
As long as sunlight is irradiated, the solar cell operates as a DC power source and outputs DC power. Solar cells are known as simple and clean energy sources because they can output direct current power without intervening other energy sources such as secondary batteries and do not discharge harmful substances.
[0003]
In a conventional solar power generation system, a plurality of solar cell modules are connected in series to form a string, and a plurality of strings are connected in parallel to form a solar cell array, and the direct current generated by the solar cell The electric power is converted into AC power in the power conditioner, and the electric power is supplied to a general AC load or an existing commercial power system. In the power conditioner, a plurality of solar cell strings are connected via a connection box that is an external device having a connection function.
[0004]
Further, the solar cell array includes a standard solar cell string composed of a standard number of solar cell modules connected in series and a non-standard string composed of less than the standard number of solar cell modules connected in series.
[0005]
For example, when installing a solar cell array on the roof of a house, depending on the shape and area of the roof, it is not possible to configure a solar cell array by arranging solar cell modules only on the south surface of the roof with the highest amount of solar radiation There is. Solar cell modules that were not placed on the south side of the roof were also placed on the west and east sides of the roof to form a solar cell string, or after the solar cell module was placed on the main part of the south side of the roof. In some cases, a solar cell string is configured including a small solar cell module arranged in the remaining region. That is, the number of solar cell modules included in some solar cell strings may be different from that of other solar cell strings, and in this case, the output voltage is different between the solar cell strings.
[0006]
When a solar cell string composed of a standard number of solar cell modules and a solar cell string composed of less than the standard series number of solar cell modules are connected in parallel to the power conditioner, the respective maximum power is obtained. Because the operating voltage is different, even if the power conditioner performs maximum power point tracking control based on the synthesized voltage-power characteristics, the combined power of each maximum power is not output, and the generated power of the solar cell Cannot be used to the maximum extent possible. In such a case, it is possible to effectively use the generated power of the solar cell by providing a booster unit in front of the power conditioner and matching the output voltage of the solar cell string less than the standard series number to the standard series number of solar cells. Become.
[0007]
FIG. 3 is a circuit block diagram showing the configuration of such a photovoltaic power generation system, and FIG. 4 is a specific block diagram of the boost control unit shown in FIG.
[0008]
In FIG. 3, this solar power generation system includes a standard solar cell string 31a, a non-standard solar cell string 31b, a boost unit 32, a connection box 40, and a power conditioner 45. Although only two solar cell strings are shown in FIG. 3 for simplification of the drawing, it goes without saying that usually more solar cell strings are included.
[0009]
The standard solar cell string 31 a is connected to the power conditioner 45 through the connection box 40, while the nonstandard solar cell string 31 b is connected to the power conditioner 45 through the booster unit 32 and the connection box 40.
[0010]
The step-up unit 32 includes a step-up circuit, a gate drive circuit, a control circuit, and a power supply circuit. The step-up circuit 33 includes a reactor 34, a transistor 35, diodes 36 and 37, and a capacitor 38 to form a step-up chopper circuit. The power supply circuit generates the power supply voltage required for the gate drive circuit and the control circuit from the boost unit input and supplies it to each circuit. The control circuit creates an ON / OFF signal for the transistor of the booster circuit in accordance with a preset booster ratio, and outputs the signal to the gate drive circuit. The control circuit performs circuit protection functions for the boost unit, start / stop control, and the like. The gate drive circuit unit drives the transistors of the booster circuit based on the ON / OFF signal output by the control circuit unit.
[0011]
As shown in FIG. 4, the boost control unit 39 includes a boost ratio setting unit 51, a signal setting calculation unit 52, a triangular wave generation unit 53, a signal comparison unit 54, and a gate drive unit 55. The step-up ratio setting unit 51 sets the ratio between the number n1 of solar cell modules included in the standard solar cell string 31a and the number n2 of solar cell modules included in the non-standard solar cell string 31b, that is, the step-up ratio n1 / n2. The boost ratio setting unit 51 is provided with a selector switch for switching the boost ratio, and the boost ratio is set by manually switching the selector switch in advance according to the solar cell strings 31a and 31b.
[0012]
Based on the boost ratio set by the boost ratio setting unit 51, the signal setting value Vt generated by the signal setting calculation unit 52 and the triangular wave signal φT generated by the triangular wave generation unit 53 and having an amplitude value from 0 to Vd are signals. The comparison unit 54 compares them. The signal comparison unit 54 performs PWM (pulse width modulation) control by outputting a gate-off level when the signal set value Vt is higher than the level of the triangular wave signal φT. The output pulse signal PS of the signal comparison unit 54 is input to the gate of the switching transistor 35 via the gate drive unit 55.
[0013]
The connection box 40 includes backflow prevention diodes 41 and 42 for preventing a backflow of current from the power conditioner 45 side to the solar cell strings 31a and 31b, and a lightning strike from the solar cell strings 31a and 31b side to the power conditioner 45 side. In order to prevent a lightning surge from entering, a lightning surge absorber 43 and a breaker 44 for connecting and disconnecting the solar cell side strings 31a and 31b and the power conditioner 45 side are included.
[0014]
The power conditioner 45 includes an inverter unit as a main circuit, a gate drive circuit, a control circuit, a display unit, and an operation unit, and is configured by a power supply circuit unit that supplies necessary power to these units. The power conditioner 45 converts the DC power supplied through the connection box 40 into AC power having the same phase and frequency 50/60 Hz as the commercial power system and supplies the AC power to the commercial power system 46. ing. In the inverter unit, the combined DC power of each solar cell string is switched through a connection box by a switching device such as an IGBT and converted into AC power. The inverter drive circuit is a circuit for turning on / off the switching device, and performs switching control such as timing for turning on / off and system control such as starting and stopping by the control circuit. In addition, the control circuit controls a display unit and an operation unit that display the operation status and generated power as user interfaces. The power supply circuit is taken out from the input part of the inverter unit, and the power to each circuit is converted into an appropriate power supply voltage by the power supply circuit and supplied.
[0015]
Next, the operation of this solar power generation system will be described. FIG. 5 is a diagram illustrating an example of output characteristics of the standard solar cell string 31a and the non-standard solar cell string 31b. In FIG. 5, the horizontal axis indicates the output voltage V of the solar cell strings 31a and 31b, and the vertical axis indicates the output power P of the solar cell strings 31a and 31b. Since the number n1 of solar cell modules of the standard solar cell string 31a is larger than the number n2 of solar cell modules of the nonstandard solar cell string 31b, the maximum output power Pa and the operating voltage Va at the maximum output of the standard solar cell string 31a. Is larger than the maximum output power Pb of the non-standard solar cell string 31b and the operating voltage Vb at the maximum output. (Pa> Pb, Va> Vb)
FIG. 6 is a diagram showing characteristics obtained by synthesizing the output characteristics of the standard solar cell string 31a and the non-standard solar cell string 31b. In the combined output characteristics, when the output voltage is Vb, the output power becomes the maximum value Pa + α (<Pa + Pb). When the boosting unit is not used, the power of the solar cell strings 31a and 31b is input to the power conditioner with this characteristic. In this case, the standard solar cell string 31a and the non-standard solar cell string 31b have different voltages Va and Vb for outputting the maximum powers Pa and Pb. Therefore, the power Pa + Pb obtained by adding the maximum powers Pa and Pb is output. Therefore, the output power of the solar cell strings 31a and 31b cannot be utilized to the maximum extent possible.
[0016]
When the booster unit 32 is used, as shown in FIG. 7, the voltage at the time of maximum power Pb output of the non-standard solar cell string 31b can be matched with the voltage Va at the time of maximum power Pa output of the standard solar cell string 31a. As a result, it is possible to output Pa + Pb obtained by adding the maximum powers Pa and Pb of the solar cell strings 31a and 31b, and the output power of the solar cell strings 31a and 31b can be utilized to the maximum extent possible.
[0017]
[Problems to be solved by the invention]
However, in the conventional solar power generation system, the boost ratio n1 / n2 of the boost unit 32 is determined based on the number n1 of solar cell modules of the standard solar cell string 31a and the number n2 of solar cell modules of the nonstandard solar cell string 31b. It is necessary to set in advance at the time of installation, and the work at the time of installation becomes complicated.
[0018]
Moreover, the number of solar cells differs and the output voltage differs depending on the type of solar cell module. In order to support all types of solar cell modules and combinations of the number of solar cell modules in series, it is necessary to prepare a large number of set values (step-up ratios) in advance. It is very complicated to confirm and set an optimum value from the set value.
[0019]
Further, even when the optimum step-up ratio is set for the combination of the types of solar cell modules and the number of series cells, the voltage ratio between the solar cell strings 31a and 31b is not always constant. For example, when the installation directions of the solar cell strings 31a and 31b are different and the element temperature of the non-solar cell string 31b changes from Ts to Ts ′ due to the influence of solar radiation or shadow, as shown in FIG. The output characteristics of the battery string 31b also change. FIG. 8 shows a state in which the maximum output power of the non-standard solar cell string 31b is reduced from Pb to Pb ′, and the voltage at the maximum output is reduced from Vb to Vb ′. In this case, as shown in FIG. 9, the output voltage Va ′ of the non-standard solar cell string 31b after boosting is lower than the output voltage Va of the standard solar cell string 31a, and the generated power of the solar cell strings 31a and 31b is maximized. It cannot be used as effectively as possible.
[0020]
Further, when the set value of the boosting ratio of the boosting unit 32 is approximated by a typical boosting ratio instead of a fine setting value for each combination of the types of solar cell modules and the number of series, it is not necessary to prepare many setting values. The operation at the time of setting is not comparatively complicated, but the operating voltage that is the maximum power is different at the set step-up ratio, and the power that is the sum of the maximum power is not output, and the generated power of the solar cell strings 31a and 31b Cannot be used to the maximum extent possible.
[0021]
Therefore, a main object of the present invention is to allow a plurality of solar cell strings having different output voltages to be simply linked to a commercial power source and to efficiently use the maximum power of the solar cell strings. That is.
[0022]
[Means for Solving the Problems]
The present invention relates to a power conditioner for converting DC power generated by a solar cell into AC power, voltage adjusting means for adjusting the voltage of the solar cell, and an inverter for converting the output of the voltage adjusting means into AC power as an input. And the inverter and the voltage adjusting means are each provided with a control circuit and a power supply circuit, and are arranged inside as a unitized inverter unit and voltage adjusting unit.
[0023]
As a result, even if solar cell strings having different numbers of series are configured, it is possible to perform maximum power follow-up control for each solar cell string, and solar cell power generated according to solar radiation conditions can be effectively utilized.
[0024]
Further, the apparatus is characterized by comprising means for communicating signals between the units.
Also, the power supply circuit of the voltage adjustment unit is supplied from the input part of each voltage adjustment unit, and the power supply circuit of the inverter unit is supplied from the point where the input part of each voltage adjustment unit is connected via a diode. .
[0025]
Further, the detection of the input voltage of the power conditioner is characterized in that the input part of each voltage adjustment unit is detected at a point connected via a diode.
[0026]
The detection of a short-circuit fault in the input portion of each voltage adjustment unit is detected by the inverter unit based on the temperature rise of each voltage adjustment unit.
[0027]
Furthermore, the inverter unit is provided with a user interface function including a display and an operation unit or an interface with a remote controller that can be remotely operated.
[0028]
The display is characterized by displaying information on each voltage adjustment unit and information on the inverter unit.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0030]
FIG. 1 is a block diagram showing a configuration for a photovoltaic power generation system according to an embodiment of the present invention. In FIG. 1, this solar power generation system includes a plurality of solar cell strings 31 a and 31 b having different numbers of series and a power conditioner 10.
[0031]
The power conditioner 10 includes voltage adjustment units 10a and 10b, an inverter unit 12, and a remote controller 13. The voltage adjustment units 10a and 10b and the inverter unit 12 are connected by bus bars 21 and 22.
[0032]
In FIG. 1, only two voltage adjustment units 10a and 10b are shown as voltage adjustment units for simplification of the drawing, but the number of units is determined on the photovoltaic power generation system according to the number of solar cell strings. It will be.
[0033]
The voltage adjustment units 10a and 10b include an input terminal unit 101, an input switch 102, a DC-DC converter 103, a power supply circuit 104, a control circuit 105, a gate drive circuit 106, an input voltage detector 107, an input current detector 108, and an output overvoltage detection. A vessel 109 is provided.
[0034]
An example of the DC-DC converter 103 is shown in FIG. The DC-DC converter 103 includes an IGBT 17 that is a switching element, a leakage transformer 25, a resonant capacitor 26, diodes 27 and 28 for voltage doubler rectification, a capacitor 29, and an output buffer capacitor 19. The gate drive circuit 106 is a circuit that receives a control signal from the control circuit 105 and drives the switching element. The control circuit 105 performs power control of the DC-DC converter 103 and controls communication between the units. The power supply circuit 104 supplies the power from the solar cell string 31b connected to the voltage adjustment unit 10b to the gate drive circuit 106 and the control circuit 105.
[0035]
In addition, two connectors 111 and 112 for supplying power to the inverter unit 12 and detecting input voltage are provided from the input switch 102 via the diode 110. Furthermore, a communication connector 113 for communicating between the units from the control circuit 105 is provided. Further, the DC-DC converter 103 is provided with a temperature fuse for detecting a temperature abnormality and outputs a signal to the inverter unit 12.
[0036]
On the other hand, the inverter unit 12 includes an inverter circuit 121, a power supply circuit 122, a control circuit 123, a gate drive circuit 124, an inverter unit input voltage detector 125, an output current detector 126, a system voltage detector 127, an interconnection relay 128, an output. A terminal unit 129 and a power conditioner input voltage detector 130 are provided.
[0037]
The inverter circuit 121 includes an IPM that is a module including a plurality of switching elements, and a reactor and a capacitor that are filters. The gate drive circuit 124 receives a control signal from the control circuit 123 and drives the switching element. The control circuit 123 performs output current control, protection control, communication with each unit, and system control of the remote control communication control power conditioner. The power supply circuit 122 supplies power from the solar cell string connected to the power conditioner 10 to the gate drive circuit 124, the control circuit 123, and the remote controller 13.
[0038]
Although not shown in detail, the remote controller 13 includes a communication circuit with a main body, a control microcomputer, a display unit, and operation switches, and the operation switches include operation / stop switching and display item switching.
[0039]
Next, power supply of each unit will be described. When the voltage adjustment units 10a and 10b receive the directly connected solar cell strings 31a and 31b as input, and the voltage of the connected solar cell strings 31a and 31b becomes equal to or higher than the specified voltage due to an increase in the amount of solar radiation, the power supply circuit 104 is activated to supply power to the control circuit 105 and the gate drive circuit 106. While the solar radiation amount continues and the solar cell strings 31a and 31b generate electricity, the power supply is continued. Moreover, when the voltage of the solar cell strings 31a and 31b becomes below a specified value due to a decrease in the amount of solar radiation, the power supply is stopped.
[0040]
On the other hand, the inverter unit 12 connects the inputs of the voltage adjustment units 10 a and 10 b via diodes and serves as the input of the power supply circuit 122. When the voltage of any solar cell string becomes equal to or higher than the specified voltage due to an increase in the amount of solar radiation, the power supply circuit 122 is activated to supply power to the control circuit 123 and the gate drive circuit 124. At this time, it is not necessary that all the voltages of the connected solar cell strings 31a and 31b become equal to or higher than a specified value. While the solar radiation amount is sustained and the solar cell strings 31a and 31b are generating power, the power supply is continued. Moreover, when the voltage of the solar cell strings 31a and 31b becomes below a specified value due to a decrease in the amount of solar radiation, the power supply is stopped. At this time, the operation continues until all the voltages of the connected solar cell strings 31a and 31b are equal to or lower than a specified value.
[0041]
Next, starting and stopping of the operation of each unit will be described. A description will be given assuming that the power supply circuit is operating. The voltage adjustment units 10a and 10b detect the voltages of the directly connected solar cell strings 31a and 31b, and start the switching operation and operate when the voltage exceeds a specified value. Further, the switching operation is stopped when the voltage of the solar cell strings 31a and 31b becomes equal to or lower than the specified value.
[0042]
On the other hand, in the inverter unit 12, the input of each voltage adjustment unit 10a, 10b is connected via a diode as a power conditioner input voltage when the system power supply is normal and there is no abnormality in the power conditioner. When the voltage at the point is detected and the voltage is equal to or higher than the specified value, and when the input voltage of the inverter unit 12 is higher than the specified value, the interconnection relay is turned on to start the switching operation. Start driving.
[0043]
Usually, the specified input voltage value of the inverter unit 12 required for starting the grid operation is set to be equal to or higher than the system power supply voltage peak voltage. If it is less than the specified value, the inrush current flowing into the electrolytic capacitors at the output of the voltage adjustment units 10a and 10b from the system power source via the inverter unit 12 when the interconnection relay 128 is turned on becomes large, which is not preferable. The inverter 10 cannot operate because the overcurrent protection function of the inverter 10 is activated.
[0044]
As for the stop, the switching operation is stopped when all the voltages of the connected solar cell strings 31a and 31b are equal to or lower than a specified value. The interconnection relay 128 is disconnected when the power of the inverter unit 12 is stopped.
[0045]
Next, the interconnection operation will be described. The voltage adjustment units 10a and 10b are control circuits 105 that calculate input power based on the input current value detected by the input current detector 108 and the input voltage value detected by the input voltage detector 107. Change the target input voltage setting value to maximize. Also, a gate pulse signal is created so that the input voltage value matches the target input voltage setting value, and if the output voltage exceeds the maximum specified voltage of the output voltage by the output overvoltage detector 109, a signal that turns off the gate is created. Then, the switching element is driven by the gate driving circuit 106 in accordance with the signal.
[0046]
On the other hand, the inverter unit 12 is inputted with the outputs of the voltage adjustment units 10a and 10b being connected in parallel. The control circuit 123 performs control so that the inverter input voltage detected by the input voltage detector 130 becomes a predetermined input operation regulation voltage. That is, when the input voltage is greater than the input operation specified voltage, control is performed to increase the target output current set value, and when the input voltage is less than the input operation specified voltage, control is performed to decrease the target output current set value. Further, the system power supply voltage is detected by the system voltage detector 127, and the control circuit 123 controls the output current waveform so as to be in phase with the system power supply voltage. The control circuit 123 detects the output current by the output current detector 126, controls the amplitude so as to coincide with the output current target set value, further creates a gate pulse, and the gate drive circuit 124 uses the signal to switch the switching element. To drive.
[0047]
Next, protection and operation at the time of abnormality will be described. When an IGBT that is a switching element of one of the plurality of voltage regulation units 10a and 10b has a short circuit failure, current flows into the corresponding voltage regulation unit from the connected solar cell string, and solar radiation is generated. Even if there is, power cannot be supplied from the power supply circuit 104. On the other hand, the failed IGBT rises in temperature due to the current flowing from the solar cell string. The inverter unit 12 detects an abnormal temperature rise, disconnects the input switch of the corresponding voltage adjustment unit, and stops the short-circuit current.
[0048]
If the gate signal cannot be turned off beyond the maximum specified voltage due to a failure of the output overvoltage detection circuit 109 of the voltage adjustment unit 10a, 10b, the withstand voltage of the diode or electrolytic capacitor of the voltage adjustment unit 10a, 10b and the IPM of the inverter unit There is a risk that the number of failures will increase. Since the outputs of the voltage adjustment units 10a and 10b are connected to the inverter unit 12, and the inverter unit 12 detects the inverter unit input voltage, the inverter unit 12 can also detect the overvoltage. When the inverter unit 12 detects an overvoltage at the location, a communication signal is output so as to inhibit the operation of each voltage adjustment unit 10a, 10b.
[0049]
When a voltage higher than the specified voltage is applied to the power conditioner 10, the inverter unit 12 detects the voltage by the power conditioner input voltage detector 125, stops the inverter by the control circuit 123 of the inverter unit 12, and each voltage adjustment unit 10a. , 10b, an abnormal signal is output by inter-unit communication, and the voltage adjustment units 10a, 10b are stopped. Further, when there is a possibility of damaging the device, the input breaker is disconnected from the control circuit 123 of the inverter unit 12.
[0050]
When the voltage adjustment units 10a and 10b cannot be operated due to other abnormalities, an error signal is output by the communication means, and the other units can be stopped by the error signal. Further, when each unit is operable depending on the type of the error signal, the other voltage adjustment units 10a and 10b and the inverter unit 12 are operated. However, it is displayed on the remote controller 13 to notify the user that a unit that cannot be operated is included.
[0051]
Next, communication between units will be described. When normal or abnormal is communicated, an error signal is output to notify the other units of the abnormality, and the other voltage adjustment units stop switching. Further, the inverter unit 12 stops the interconnection operation, displays a status on the remote controller 13, and notifies the user. An example of a communication circuit is shown in the figure.
[0052]
Further, when the operation state / power information is communicated between the units, the inverter unit 12 is used as a host, and a request signal is output to each voltage adjustment unit 10a, 10b. Each voltage adjustment unit 10a, 10b Returns power data. When the operation state is abnormal, a code indicating the content of the abnormality is transmitted instead of the output power. Also, when an abnormality is detected in the inverter unit, or when abnormality information is received from the voltage adjustment unit and other voltage adjustment units need to be stopped, an error signal is output to each voltage adjustment unit 10a, 10b, Each voltage regulation unit stops.
[0053]
Next, display will be described. The display section of the remote controller 13 shows the operating status (running / stopping), operating power, integrated power consumption from installation, period power consumption within a certain period, converted value of carbon dioxide reduction, and status in case of abnormal stop. The error code to be displayed and the power display during operation include the output power of the power conditioner 10 and the generated power (input power of the voltage adjusting unit) of each of the solar cell strings 31a and 31b. Each display content is arbitrarily switched by the user with an operation key, or automatically at regular intervals.
[0054]
The embodiment disclosed this time should 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 description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0055]
【The invention's effect】
As described above, according to the present invention, even if the characteristics of all the solar cell strings connected to the power conditioner are different, it is possible to take out the maximum output according to the characteristics of each solar cell string. Battery power can be used effectively. That is, even if solar cell strings having different numbers of series are configured, it is possible to perform maximum power tracking control for each solar cell string, and solar cell generated power corresponding to solar radiation conditions can be effectively utilized.
[0056]
Moreover, it becomes possible to arrange | position an internal voltage adjustment unit according to the number of solar cell strings to install, and the apparatus according to a system capacity | capacitance can be manufactured easily.
[0057]
By providing a power supply circuit and a control circuit for each unit, each voltage adjustment unit performs maximum power tracking control and output overvoltage protection, and each unit operates independently by performing input voltage and output current control, Inverter operation is possible.
[0058]
The power supply circuit of the inverter unit is not supplied from the voltage adjustment unit output but via the diode connection from the voltage adjustment unit input, so that the solar cell is generating power, but the voltage adjustment unit cannot operate due to an abnormality, etc. Even in this case, since the power supply circuit operates in the inverter unit, an abnormal state can be detected. In addition, information can be displayed on the remote controller to notify the user.
[0059]
In addition, by performing communication between the units, the units normally operate independently. However, when an abnormality occurs, it is possible to detect the abnormal state and reliably perform the protective operation. In addition, the inverter unit responsible for the main control can perform centralized management of each unit by performing communication control of the remote controller. In normal times, the generated power of each unit can be displayed, and abnormal information can be displayed in the event of an abnormality. .
[0060]
In addition, when an IGBT, which is a switching element of one of the plurality of voltage adjustment units, has a short circuit failure, the corresponding voltage adjustment unit loses the power supply, and therefore detects the voltage adjustment unit having a short circuit failure. However, since another solar cell string power supply is supplied to the inverter unit and the temperature increase of the IGBT is detected by the inverter unit, a short-circuit state can be detected, so that a protective operation and information display are possible.
[0061]
Further, by detecting the inverter input voltage with the inverter unit, an input undervoltage and input overvoltage protection operation can be performed. In the case of an undervoltage, it is possible to detect that the voltage of all the solar cell strings is equal to or lower than a specified value, and in the case of an overvoltage, it is possible to detect that any one solar cell string is equal to or higher than the specified value.
[0062]
That is, it is possible to communicate operation information such as output power or failure information due to occurrence of an abnormality, to safely operate or stop the power conditioner, and display the information to notify the user.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
2 is a circuit block diagram showing a configuration of the DC-DC converter shown in FIG. 1. FIG.
FIG. 3 is a circuit block diagram showing a configuration of a conventional photovoltaic power generation system.
4 is a block diagram showing a configuration of a boost control unit shown in FIG. 3. FIG.
5 is an operation explanatory diagram of the photovoltaic power generation system shown in FIG. 3. FIG.
6 is an operation explanatory diagram of the photovoltaic power generation system shown in FIG. 3. FIG.
7 is an operation explanatory diagram of the photovoltaic power generation system shown in FIG. 3. FIG.
8 is a diagram for explaining problems of the photovoltaic power generation system shown in FIG. 3. FIG.
FIG. 9 is a diagram for explaining problems of the photovoltaic power generation system shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Power conditioner, 10a, 10b Voltage adjustment unit, 12 Inverter unit, 13 Remote controller, 21, 22 Bus bar, 31a, 31b Solar cell string, 101 Input terminal, 102 Input switch, 103 DC-DC converter, 104, 122 Power supply Circuit, 105, 123 Control circuit, 106, 124 Gate drive circuit, 107, 125, 130 Input voltage detector, 108 Input current detector, 110 Backflow prevention diode, 111-113 connector, 121 Inverter circuit, 126 Output current detection , 127 system voltage detector, 128 interconnection relay, 129 output terminal part.

Claims (7)

  1. A power conditioner that converts DC power generated by a solar cell into AC power,
    Voltage adjusting means for adjusting the voltage of the solar cell;
    An inverter that converts the output of the voltage adjusting means into AC power as an input;
    The inverter and the voltage adjustment means are each provided with a control circuit and a power supply circuit, and are arranged inside as a unitized inverter unit and voltage adjustment unit, a power conditioner for a photovoltaic power generation system.
  2. The power conditioner for a photovoltaic power generation system according to claim 1, further comprising means for communicating a signal between the units.
  3. The power supply circuit of the voltage regulation unit is supplied from the input part of each voltage regulation unit,
    The power conditioner for a photovoltaic power generation system according to claim 1, wherein the power supply circuit of the inverter unit supplies the input part of each voltage adjustment unit from a point connected via a diode.
  4. The power conditioner for a photovoltaic power generation system according to claim 1, wherein the input voltage of the power conditioner is detected at a point where an input portion of each voltage adjustment unit is connected via a diode.
  5. 2. The power conditioner for a photovoltaic power generation system according to claim 1, wherein the detection of a short-circuit fault in the input portion of each voltage adjustment unit is detected by a temperature increase of each voltage adjustment unit by an inverter unit.
  6. The power conditioner for a photovoltaic power generation system according to claim 1, wherein the inverter unit has a user interface function including a display and an operation unit or an interface with a remote controller that can be remotely operated.
  7. The power conditioner for a photovoltaic power generation system according to claim 1, wherein the display displays information on each voltage adjustment unit and information on an inverter unit.
JP2002091886A 2002-03-28 2002-03-28 Power conditioner for photovoltaic system Expired - Fee Related JP3796460B2 (en)

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