JP2008005638A - Power supply - Google Patents

Abstract

In isolated operation detection in a grid-connected inverter, reliable and high-speed detection performance and the influence on the load and system facilities due to an active disturbance signal are minimized by compensating distortion components, and power supply It aims at providing the power supply device carrying the isolated operation detection system which can make stabilization compatible.
A power supply apparatus includes a grid interconnection inverter unit 3 that outputs generated power from a solar cell 1 serving as a power generation unit to a grid power source 2, and a power saving unit 5 that reduces power supplied to a load 4. When the isolated operation detection means 3a provided in the grid interconnection inverter unit 3 determines that there is a possibility of a power failure, the power command of the power control unit 5a provided in the power saving unit 5 is disrupted. By providing the command changing means 6 to be changed, the isolated operation is more reliably detected and stopped.
[Selection] Figure 1

Description

  The present invention relates to a grid-connected inverter used for photovoltaic power generation using inverter technology.

  In recent years, fossil fuel depletion and global warming have occurred due to an increase in the load on ordinary households. Use of clean energy and energy-saving devices such as solar power generation systems, power-saving devices, and system voltage stabilization devices have been developed. It has been demanded.

  Conventionally, a grid interconnection inverter in this type of photovoltaic power generation system is known to output a disturbance signal to the system in an active manner and detect it by divergence of the disturbance signal (for example, Patent Document 1 or Patent Document). 2).

  Hereinafter, detection of an isolated operation in Patent Document 1 will be described with reference to FIG.

  As shown in the figure, a power source device 7 that outputs DC power, such as a solar cell, an inverter circuit 8 that converts DC power output from the power source device 7 into AC power, and a load 9 that is linked to the inverter circuit 8. Based on the voltage at the connection point detected by the voltage detection means 11, the voltage detection means 11 for detecting the voltage at the connection point between the inverter circuit 8 and the commercial power system 10. The commercial power system 10 is stopped and the single operation determination unit 12 that determines that the commercial power system 10 is in the single operation state, the active fluctuation creation unit 13 that varies the output current of the inverter circuit 8, and the commercial power system 10 are stopped. When the isolated operation determination unit 12 determines that the system is in the isolated operation state, it has a system interconnection protection device 14 that disconnects the inverter circuit 8 and the commercial power system 10. When the output current of the inverter circuit 8 is varied, a random variation output unit 15 is provided, so that a random value is selected from a certain range of numerical values, and an active variation signal is generated with a random amount variation amount at predetermined time intervals. Will be output. By giving a random value variation, it is possible to detect an isolated operation even when a power generation facility that employs an active method is connected to the same wiring.

  Next, detection of isolated operation in Patent Document 2 will be described with reference to FIG.

  FIG. 11 shows the configuration of the inverter device 16. The inverter device 16 converts the DC power input from the DC power supply 17 into AC power and supplies it to the load 18; the voltage detector 20 that detects the load supply voltage Vo supplied to the load 18; A zero-cross detection circuit 21 that generates the output synchronization signal Vs based on the load supply voltage Vo, a current detector 22 that detects the output current Io of the inverter main circuit 19, and an A / D that converts the output current Io from analog to digital. Converter 23, digital signal processor 24 for PWM control of inverter main circuit 19 based on output current Io and output synchronization signal Vs, and voltage abnormality for detecting voltage abnormality of load supply voltage Vo supplied to load 18 A timer count that generates a gate pulse signal Gp based on the PWM data output from the detection circuit 25 and the digital signal processor 24 A circuit 26, and a gate drive circuit 27 for controlling switching of switching elements of the inverter main circuit 19 based on the gate pulse signal Gp.

In this inverter device 16, when the AC power system 28 becomes a single operation state due to a power failure or the like, when the active power from the inverter device 16, the reactive power and the active power of the load 18, the reactive power is unbalanced, When an abnormality in the load supply voltage Vo or the frequency of the load supply voltage is detected and the single operation state is entered, the switching control of the inverter main circuit 19 is stopped, whereby the inverter main circuit 19 stops the inverter output. Next, when the inverter device 16 enters the single operation state in a state where the active power and reactive power supplied by the inverter device 16 substantially match the active power and reactive power required by the load 18, the load supply voltage Vo And since the frequency hardly fluctuates, by adding distortion to the inverter output, regardless of the power factor of the load impedance, the frequency of the load supply voltage Vo in the single operation state is changed and the single operation state is reliably detected. is doing.
Japanese Patent No. 3402159 (FIG. 1) JP-A-8-134656 (FIG. 1)

  The isolated operation detection in such a conventional grid-connected inverter outputs a disturbance signal to the system in an active manner, but the disturbance affects the load and the system equipment, especially in practice. At the moment when a power outage accident occurs, there is a problem that the power supply environment such as the frequency suddenly rises or falls, or the voltage suddenly rises or falls, and there is a problem that the load may be damaged in some cases. There is a need for stability in supply.

  Further, even when the system power supply is in a healthy state, the distortion of the system may increase due to the distortion output from the system interconnection inverter. In particular, when grid-connected inverters are installed concentrated in a specific area, and the grid-operated operation is performed, there is a problem in that the system is adversely affected by distortion components such as power harmonics. In addition, since there is a possibility of an isolated operation due to a decrease in sensitivity of the isolated operation detection function due to concentration in a specific area, there is a risk of an electric shock accident during maintenance of the system power supply, such as power harmonics. There is a demand for detecting an isolated operation more reliably and at high speed while suppressing distortion.

  The present invention solves such a conventional problem, and compensates for the distortion component superimposed on the output of the grid interconnection inverter, so that even when an actual power outage accident occurs, a sudden change in frequency ( By connecting a grid-connected inverter, the power supply environment is deteriorated due to a power failure, or even when the system power supply is healthy, while suppressing power supply harmonics and more reliably and faster. Another object of the present invention is to provide a power supply device that can detect an isolated operation.

  In order to achieve the above object, a power supply device of the present invention is a power supply device having a grid interconnection inverter unit that outputs generated power from power generation means to a grid power source, and a power saving unit that reduces power supplied to a load. When the isolated operation detection means provided in the grid interconnection inverter unit determines that there is a possibility of a power failure, the power command of the power control unit provided in the power saving unit is changed so as to disrupt the power supply / demand balance. It is set as the structure provided with the instruction | command change means to do.

  By this means, when it is determined that there is a possibility of a power outage, the power supply / demand is forcibly brought into an unbalanced state, and the output voltage of the grid interconnection inverter part fluctuates by breaking the balance of the power supply / demand. The isolated operation detection function of the grid-connected inverter unit that detects the fluctuation can be detected more reliably and at high speed, and the safety of the maintenance worker of the power distribution equipment can be ensured.

  The command changing means is configured to control in a direction to stop power saving.

  By this means, when it is determined that there is a possibility of a power failure and the system side is in a healthy state, that is, when an unnecessary operation occurs, the instantaneous disturbance of the load supply voltage due to the command change is suppressed. Can do.

  Further, the command changing means is configured to control power saving in a direction to accelerate.

  By this means, when it is determined that there is a possibility of a power failure, an increase in load supply voltage can be suppressed.

  The isolated operation detecting means is configured to superimpose a disturbance on the frequency of the current output from the grid interconnection inverter unit.

  By this means, a special circuit for detecting the isolated operation is not required, and the isolated operation detection function can be realized with a simpler and less expensive configuration.

  Furthermore, the isolated operation detection means is configured to superimpose a disturbance on a predetermined phase of the current output from the grid interconnection inverter unit.

  By this means, a special circuit for detecting the isolated operation is not required, and the isolated operation detection function can be realized with a simpler and less expensive configuration.

  Further, the isolated operation detection means is configured to superimpose a disturbance on the reactive power output from the grid interconnection inverter unit.

  By this means, a special circuit for detecting the isolated operation is not required, and the isolated operation detection function can be realized with a simpler and less expensive configuration.

  Furthermore, the power saving unit is configured to superimpose electric power that cancels the disturbance superimposed by the isolated operation detecting means.

  By this means, since the disturbance for detecting the isolated operation is canceled by the power saving unit, the adverse effect on the load or the system can be suppressed.

  Further, the power saving unit is configured to monitor the grid current and determine the power to be canceled.

  By this means, it is possible to more effectively detect the influence of disturbance on the system side to detect islanding operation, and cancel the adverse effects at the power-saving part, so that the adverse effect on the load or system is further effective. Can be suppressed.

  Furthermore, the power saving unit is configured by a series transformer and a full bridge inverter.

  By this means, the power saving unit is connected in parallel to the system or load, so that in the event of an abnormal failure of the device, the device can be disconnected from the system side and power can be sent directly, so the stability of power supply to the load is improved. Can be improved.

  Moreover, the full-bridge inverter of the power saving unit and the full-bridge inverter provided in the grid interconnection inverter unit are configured to share one arm.

  By this means, the configuration can be simplified, so that it can be realized with a small and low-cost apparatus.

  Furthermore, the command value of the command changing means is configured to have a predetermined change amount as an upper and lower limit value.

  By this means, it is possible to detect an isolated operation within a healthy voltage range without exceeding the normal fluctuation range of the system voltage by changing the command.

  Also, the feedforward control is performed by calculating the compensation amount to be compensated by the power saving unit from the disturbance superimposed by the isolated operation detecting means.

  By this means, it is possible to prevent adverse effects on the power distribution equipment by improving the compensation response to disturbance generated by the apparatus.

  According to the present invention, there is provided a power supply device having a grid interconnection inverter unit that outputs generated power from a power generation means to a grid power source, and a power saving unit that reduces power supplied to a load, wherein the grid interconnection inverter unit A command change means for changing the power command of the power control means provided in the power saving unit so as to break the power supply-demand balance when the isolated operation detection means provided in Therefore, when it is determined that there is a possibility of a power failure, the power supply and demand can be forced to be unbalanced, and the isolated operation of the grid interconnection inverter can be detected more reliably, and maintenance of the power distribution equipment It is possible to provide a power supply device having an effect of ensuring the safety of the worker.

  In addition, the command changing means is configured to control in a direction to stop power saving, so that it is determined that there is a possibility of a power failure and the system side is in a healthy state, that is, an unnecessary operation has occurred. In this case, it is possible to provide a power supply device that is effective in suppressing an instantaneous disturbance of the load supply voltage due to a command change.

  Further, the command changing means is configured to control power saving in a direction that accelerates power, so that it is possible to suppress an increase in load supply voltage when it is determined that there is a possibility of a power failure. Can provide.

  In addition, the islanding operation detection means is configured to superimpose disturbance on the frequency of the current output from the grid interconnection inverter unit, so that a special circuit for detecting islanding operation is not required, and it is simpler and more It is possible to provide a power supply device that is effective in that the isolated operation detection function can be realized with an inexpensive configuration.

  Furthermore, the isolated operation detection means is configured to superimpose a disturbance on the predetermined phase of the current output from the grid interconnection inverter unit, so that it does not require a special circuit for detecting isolated operation and is simpler. In addition, it is possible to provide a power supply apparatus having an effect that the isolated operation detection function can be realized with a cheaper configuration.

  In addition, the isolated operation detection means is configured to superimpose the disturbance on the reactive power output from the grid interconnection inverter unit, so that a special circuit for detecting isolated operation is not required, and it is simpler and less expensive. Thus, it is possible to provide a power supply device having an effect of being able to realize the isolated operation detection function with a simple configuration.

  Furthermore, the power saving unit is configured to superimpose power that cancels the disturbance superimposed by the isolated operation detection means, so that the disturbance for detecting isolated operation is canceled by the power saving unit. It is possible to provide a power supply device having an effect of being able to be suppressed.

  In addition, the power saving unit is configured to determine the power to be canceled by monitoring the system current, so that it is possible to more effectively detect the influence on the system side of the disturbance for detecting isolated operation. Since the minutes are canceled out by the power saving unit, it is possible to provide a power supply device that can effectively suppress the adverse effect on the load or the system.

  Furthermore, the power saving unit is configured with a series transformer and a full bridge inverter, so that the power saving unit is connected in parallel to the system or load. Since direct transmission is possible, it is possible to provide a power supply device that is effective in improving the stability of power supply to the load.

  In addition, the full-bridge inverter in the power-saving unit and the full-bridge inverter provided in the grid-connected inverter unit can be simplified in configuration by sharing one arm. It is possible to provide a power supply device that can be realized.

  Furthermore, the command value of the command change means is configured to have a predetermined change amount as the upper and lower limit values, so that it is possible to detect an isolated operation in a healthy voltage range without exceeding the normal system voltage fluctuation range due to the command change. Therefore, it is possible to provide a power supply device that has the effect of being able to perform the above.

  In addition, by calculating the amount of compensation to be compensated by the power saving unit from the disturbance superimposed by the isolated operation detecting means and performing the feedforward control, the compensation response to the disturbance generated from the apparatus is improved. Thus, it is possible to provide a power supply device that is effective in preventing adverse effects on the power distribution equipment.

  Invention of Claim 1 of this invention is a power supply device which has the grid connection inverter part which outputs the electric power generated from an electric power generation means to a system power supply, and the power-saving part which reduces the electric power supplied to load, Command change to change the power command of the power control means provided in the power saving unit so as to disrupt the power supply-demand balance when the isolated operation detection means provided in the grid interconnection inverter unit determines that there is a possibility of power failure When it is determined that there is a possibility of a power outage, the power supply / demand is forced to be unbalanced, and when the power supply / demand balance breaks down, the voltage rises or falls when a power outage accident occurs. Since a phenomenon such as an increase or decrease occurs, the isolated operation of the grid-connected inverter unit can be detected more reliably, reducing the risk of electric shock accidents, etc. An effect that it is possible to ensure maintenance worker safety Bei.

  Also, the command change means is configured to control in the direction to stop power saving, and it is determined that there is a possibility of a power failure and when the system side is in a healthy state, that is, unnecessary operation occurs. In this case, since the system power supply is brought close to the direct power supply state, instantaneous disturbance of the load supply voltage due to the command change can be suppressed.

  Furthermore, the command changing means is configured to control power saving in the direction of acceleration, and when it is determined that there is a possibility of a power failure, the power supply / demand balance is adjusted even when the load is small. Thus, it is possible to suppress an increase in load supply voltage.

  Further, the isolated operation detecting means is configured to superimpose disturbance on the frequency of the current output from the grid interconnection inverter unit, and does not require a special circuit for detecting isolated operation, and is simpler and It has the effect | action that an independent operation detection function is realizable with a cheaper structure.

  Furthermore, the isolated operation detecting means is configured to superimpose a disturbance on a predetermined phase of the current output from the grid interconnection inverter unit, and does not require a special circuit for detecting isolated operation, and is simpler. In addition, the isolated operation detection function can be realized with a cheaper configuration.

  In addition, the isolated operation detection means is configured to superimpose disturbance on the reactive power output from the grid interconnection inverter unit, does not require a special circuit for detecting isolated operation, is simpler and more It has the effect that the isolated operation detection function can be realized with an inexpensive configuration.

  Furthermore, the power saving unit is configured to superimpose electric power that cancels the disturbance superimposed by the isolated operation detecting means. Since the disturbance for detecting isolated operation is canceled by the power saving unit, there is an adverse effect on the load or the system. It has the effect | action that it can suppress.

  In addition, the power saving unit is configured to determine the power to be canceled by monitoring the system current, and can more effectively detect the influence on the system side of the disturbance for detecting the isolated operation. Since the adverse effect is canceled out by the power saving unit, the adverse effect on the load or the system can be more effectively suppressed.

  In addition, the power saving unit is composed of a series transformer and a full bridge inverter. In order to connect the power saving unit in parallel to the system or load, the device is disconnected from the system side in the event of an abnormal failure of the device. Therefore, the stability of power supply to the load can be improved.

  In addition, the full-bridge inverter in the power-saving unit and the full-bridge inverter provided in the grid-connected inverter unit are configured to share one arm, and the configuration can be simplified, resulting in a compact and low-cost device. It has the effect that it can be realized.

  Furthermore, the command value of the command change means is configured to have a predetermined change amount as an upper and lower limit value, so that it does not exceed the fluctuation range of the normal system voltage due to the command change and can be operated independently in a healthy voltage range. It has the effect | action that it can detect.

  In addition, a compensation amount to be compensated by the power saving unit is calculated from the disturbance superimposed by the isolated operation detecting means, and feedforward control is performed. This improves the compensation responsiveness to the disturbance generated from the apparatus. Thus, it has an effect that an adverse effect on the power distribution equipment can be prevented.

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

(Embodiment 1)
FIG. 1 is a configuration diagram of a power supply device according to the first embodiment.

  As shown in the figure, the power supply device has a grid-connected inverter unit 3 that outputs generated power from a solar cell 1 as power generation means to a system power source 2 and a power saving unit 5 that reduces power supplied to a load 4. When the isolated operation detection means 3a provided in the grid interconnection inverter unit 3 determines that there is a possibility of a power failure, the power command of the power control means 5a provided in the power saving unit 5 is disrupted. The command changing means 6 for changing is provided.

  Next, the basic operation of the power control means 5a will be described with reference to FIG. As shown in the figure, the power control means 5a includes a series transformer 5b connected in series with the system power supply 2, a power saving inverter 5c connected to the series transformer 5b, and a power saving control unit 5d controlled by the power saving inverter 5c. ing. The power saving control unit 5d detects the voltage supplied to the load 4, and controls the voltage applied to the series transformer 5b in comparison with the command voltage. As a result, since the voltage vector induced at both ends of the series transformer 5b and the voltage vector of the system power supply 2 can be combined, the voltage supplied to the load 4 can be controlled to the command voltage. For example, assuming that the system voltage is 105V, the command voltage is 100V, and the primary / secondary turns ratio of the series transformer 5b is 1:10, the voltage across the power saving inverter 5c is controlled to 50V.

  Next, the isolated operation detection means 3a will be described. The isolated operation detection means 3a superimposes a disturbance on the current command value so as to reduce the frequency of the current output from the grid interconnection inverter unit 3. For example, a disturbance having a frequency that does not adversely affect the power source, such as 0.01 Hz to 0.05 Hz, is superimposed on the power source frequency. The disturbance of the frequency gives distortion to the current output from the grid interconnection inverter unit 3. In the isolated operation state, i.e., the power failure state, applying this distortion causes the frequency to change in the direction in which the disturbance is superimposed (for example, a decrease of 0.01 Hz). It is determined that there is a possibility that an operation, that is, a power failure has occurred.

  Next, FIG. 2 shows a control flowchart of the command changing means 6 when the isolated operation detecting means 3a determines that there is a possibility of a power failure. As shown in the figure, a signal indicating whether or not there is a possibility of a power failure is input from the isolated operation detection means 3a. When there is a possibility of a power failure and there is a signal input, the command changing means 6 controls the power control means 5a to reduce the control command value, that is, the voltage setting value, for example, by 1 V, that is, to accelerate power saving. Here, the direction of accelerating power saving means increasing the power saving power, and indicates that the power saving power is changed from 50 W to 100 W, for example. However, the lower limit is set so that the voltage of the load 4 does not fall below 95V. At this time, if the load 4 has a device whose power consumption changes according to the input voltage, that is, the internal circuit does not perform control according to the input voltage and has a load 4a mainly including a resistance component, the load 4 responds to the voltage drop. Therefore, the effective power consumed will decrease. Due to this command value change, the supply and demand of electric power will transition to an unbalanced state even in a balanced state. When the command changing means 6 decreases the voltage set value, it inputs whether or not the isolated operation detecting means 3a has determined that there is a power failure, and if it is determined that there is no power failure for a specified time (for example, 100 ms). Restore the voltage setting to the value before the change. If it is determined that a power failure has occurred within the specified time, a stop command is transmitted to the power control means 5a.

  With the above configuration, when it is determined that there is a possibility of a power failure, the power supply / demand is forcibly brought into an unbalanced state, and the isolated operation of the grid interconnection inverter unit 3 is more reliably detected.

  As described above, according to the first embodiment, it is possible to detect more quickly and reliably even in a state where it is difficult to detect an isolated operation in which the supply and demand of electric power is balanced or the detection speed is reduced. it can.

  In the first embodiment, the voltage set value is reduced by 1 V when controlling power saving in the acceleration direction. However, if the reduction is in accordance with the system capacity, the change width is reduced by 0.5 V, or There is no difference in effect even when the change width of 2 V is increased.

  Further, although the power control means 5a is configured to include the power saving inverter 5c, there is no difference in operational effect even if the voltage control value is decreased by switching the taps of the series transformer 5b.

(Embodiment 2)
FIG. 3 is a configuration diagram of the power supply device according to the second embodiment.

  In addition, the same thing as Embodiment 1 attaches | subjects the same symbol, and abbreviate | omits detailed description.

  As shown in the figure, the power supply device has a grid-connected inverter unit 3B that outputs the generated power from the solar cell 1 as power generation means to the system power source 2, and a power saving unit 5 that reduces the power supplied to the load 4. The command change means 6B for changing the power command of the power control means 5a provided in the power saving section 5 when the isolated operation detection means 3Ba provided in the grid interconnection inverter section 3B determines that there is a possibility of power failure. It has.

  Next, the independent operation detection means 3Ba will be described. The isolated operation detecting means 3Ba superimposes a disturbance on a predetermined phase of the current output from the grid interconnection inverter unit 3B. For example, a disturbance having a frequency that does not adversely affect the power supply is superimposed on the zero cross point. The disturbance of the frequency superimposed on the zero cross point will distort the current output from the grid interconnection inverter unit 3B.

  Next, FIG. 4 shows a control flowchart of the command changing means 6B when the isolated operation detecting means 3Ba determines that there is a possibility of power failure. As shown in the figure, a signal indicating the possibility of a power failure is input from the isolated operation detection means 3Ba. When there is a possibility of a power failure and there is a signal input, the command changing means 6B increases the control command value of the power control means 5a, that is, the voltage set value, for example, by 1V, that is, controls the direction to stop power saving. Here, the direction of stopping power saving means to reduce power saving power, and for example, indicates that the power saving power is changed from 100 W to 50 W. However, the upper limit value is set so that the voltage of the load 4 does not exceed 107V. At this time, if the load 4 has a device whose power consumption changes according to the input voltage, that is, the internal circuit does not perform the control according to the input voltage and the load 4a mainly including a resistance component, the load 4 responds to the voltage rise. As a result, the effective power consumed increases. Due to this command value change, the supply and demand of electric power will transition to an unbalanced state even in a balanced state. When the command changing means 6B increases the voltage set value, it inputs whether or not the isolated operation detecting means 3Ba has determined that there is a power failure, and if it is determined that there is no power failure for a specified time (for example, 100 ms) Restore the voltage setting to the value before the change. If it is determined that a power failure has occurred within the specified time, a stop command is transmitted to the power control means 5a.

  With the above configuration, when it is determined that there is a possibility of a power failure, the power supply and demand is forcibly brought into an unbalanced state, and the isolated operation of the grid interconnection inverter unit 3B is more reliably detected.

  As described above, according to the second embodiment, it is possible to detect more quickly and reliably even in a state where it is difficult to detect an isolated operation in which the supply and demand of electric power is balanced or the detection speed is reduced. it can.

  In the second embodiment, the voltage set value is increased by 1 V when controlling in the direction of stopping power saving. However, if the increase is in accordance with the system capacity, the change width is reduced by 0.5 V, or There is no difference in effect even when the change width of 2 V is increased.

  Moreover, although the power control means 5a is configured to include the power saving inverter 5c, there is no difference in operation and effect even if the voltage control value is increased by switching a plurality of taps of the series transformer 5b.

(Embodiment 3)
FIG. 5 is a configuration diagram of the power supply device according to the third embodiment.

  In addition, the same thing as Embodiment 1 or Embodiment 2 attaches | subjects the same symbol, and abbreviate | omits detailed description.

  As shown in the figure, the power supply device has a grid-connected inverter unit 3C that outputs the generated power from the solar cell 1 as a power generation means to the system power source 2, and a power saving unit 5 that reduces the power supplied to the load 4. The command change means 6B for changing the power command of the power control means 5a provided in the power saving section 5 when the isolated operation detection means 3Ca provided in the grid interconnection inverter section 3C determines that there is a possibility of power failure. It has.

  Next, the independent operation detection means 3Ca will be described. The isolated operation detection means 3Ca superimposes predetermined reactive power on the current output from the grid interconnection inverter unit 3C. The predetermined reactive power is, for example, reactive power in a range where the power factor does not fall below 0.85.

  With the above configuration, when it is determined that there is a possibility of a power failure, the power supply / demand is forcibly brought into an unbalanced state, and the isolated operation of the grid-connected inverter unit 3C is more reliably detected.

  As described above, according to the third embodiment, it is possible to detect more rapidly and reliably even in a state where it is difficult to detect an isolated operation in which the supply and demand of electric power is balanced or the detection speed is reduced. it can.

(Embodiment 4)
FIG. 6 is a configuration diagram of the power supply device according to the fourth embodiment.

  In addition, the same thing as Embodiment 1-3 is attached | subjected the same symbol, and detailed description is abbreviate | omitted.

  As shown in the figure, the power supply device is a grid-connected inverter unit 3 that outputs the generated power from a solar cell 1 as a power generation means to the system power supply 2 and the isolated operation detection means 3a while simultaneously reducing the power supplied to the load 4. If the isolated operation detecting means 3a provided in the grid interconnection inverter unit 3 determines that there is a possibility of a power failure, the power saving unit 5B Command change means 6 for changing the power command of the provided power control means 5Ba is provided.

  Next, a control flowchart of the power saving unit 5B will be described with reference to FIG. As shown in the figure, the power saving unit 5B receives the disturbance amount superimposed from the grid interconnection inverter unit 3. It is determined whether or not the received disturbance amount is a disturbance amount that can be compensated by the power saving unit 5B. If the amount exceeds the upper limit, the upper limit value is set as the compensation amount. The compensation amount to be compensated by the power saving unit 5B is calculated, limited by the upper limit value, and the compensation amount is determined by feedforward control. Further, the compensation amount is output to the power control means 5Ba. Further, the power saving unit 5B outputs the compensation amount to the isolated operation detecting means 3a, and the isolated operation detecting means 3a detects the isolated operation from the output disturbance amount and compensation amount.

  With the above configuration, the power saving unit 5B cancels the disturbance superimposed by the single operation detection means 3a.

  As described above, according to the fourth embodiment, it is possible to reliably detect a single operation at high speed and to suppress an adverse effect on the load or the system with a quicker response speed.

(Embodiment 5)
FIG. 8 is a configuration diagram of the power supply device according to the fifth embodiment.

  In addition, the same thing as Embodiment 1-4 is attached | subjected the same symbol, and detailed description is abbreviate | omitted.

  As shown in the figure, the power supply device monitors the grid current at the same time as reducing the power supplied to the grid-connected inverter unit 3 that outputs the generated power from the solar cell 1 as the power generation means to the grid power supply 2 and the load 4. The power saving unit 5C that superimposes the electric power to cancel the disturbance superimposed by the isolated operation detecting means 3a, and the isolated operation detecting means 3a provided in the grid interconnection inverter unit 3 determines that there is a possibility of power failure In addition, a command changing means 6 for changing the power command of the power control means 5Ca provided in the power saving unit 5C is provided.

  Next, a control flowchart of the power saving unit 5C will be described with reference to FIG. As shown in the figure, the power saving unit 5C calculates the grid current effective value from the instantaneous detection value of the grid current. A disturbance amount that can be superimposed by the isolated operation detecting means 3a is calculated from the calculated system current effective value. It is determined whether or not the calculated disturbance amount is a disturbance amount that can be compensated by the power saving unit 5C, and if the upper limit is exceeded, the compensation amount is set to the upper limit value. If it is within the compensation range, the compensation amount is output to the power control means 5Ca. Further, the power saving unit 5C outputs the compensation amount to the isolated operation detection means 3a, and the isolated operation detection means 3a detects the isolated operation from the output disturbance amount and compensation amount.

  With the above configuration, the power saving unit 5C cancels the disturbance superimposed by the single operation detection means 3a.

  As described above, according to the fifth embodiment, it is possible to reliably detect a single operation at high speed and to suppress adverse effects on the load or the system.

  Applications that require centralized installation of power generation systems while maintaining harmony with the system side, because voltage fluctuations of the system power supply can be suppressed, and the system power supply can be detected at a higher speed and disconnected from the system power supply. It can also be applied to.

1 is a configuration diagram of a power supply device according to a first embodiment of the present invention. Control flow chart of the command changing means 6 Configuration diagram of a power supply device according to a second embodiment of the present invention Control flow chart of the command changing means 6B Configuration diagram of power supply device according to Embodiment 3 of the present invention Configuration diagram of a power supply device according to a fourth embodiment of the present invention Control flowchart of power saving unit 5B Configuration diagram of a power supply device according to a fifth embodiment of the present invention Control flowchart of power saving unit 5C Explanatory drawing about the independent operation detection method of the conventional patent document 1 Explanatory drawing about the independent operation detection method of the conventional patent document 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 System power supply 3, 3B, 3C System interconnection inverter part 3a, 3Ba, 3Ca Single operation detection means 4, 4a Load 5, 5B, 5C Power saving part 5a, 5Ba, 5Ca Power control means 5b Series transformer 5c Power saving Inverter 5d Power saving control unit 6, 6B Command changing means

Claims (12)

A power supply device having a grid-connected inverter unit that outputs generated power from a power generation means to a grid power source and a power-saving unit that reduces power supplied to a load, the islanding operation detection provided in the grid-connected inverter unit A power supply apparatus comprising: a command changing unit that changes a power command of a power control unit provided in the power saving unit when it is determined that there is a possibility of a power failure. The power supply apparatus according to claim 1, wherein the command changing unit performs control in a direction to stop power saving. The power supply apparatus according to claim 1, wherein the command changing unit controls power saving in a direction to accelerate. 2. The power supply device according to claim 1, wherein the isolated operation detecting means superimposes a disturbance on the frequency of the current output from the grid interconnection inverter unit. The power supply apparatus according to claim 1, wherein the isolated operation detecting means superimposes a disturbance on a predetermined phase of the current output from the grid interconnection inverter unit. 2. The power supply apparatus according to claim 1, wherein the isolated operation detection means superimposes a disturbance on the reactive power output from the grid interconnection inverter unit. 2. The power supply apparatus according to claim 1, wherein the power saving unit superimposes electric power that cancels the disturbance superimposed by the isolated operation detecting means. The power saving device according to claim 7, wherein the power saving unit determines the power to be canceled by monitoring the system current. 2. The power supply device according to claim 1, wherein the power saving unit is constituted by a series transformer and a full bridge inverter. The power supply device according to claim 9, wherein the full bridge inverter of the power saving unit and the full bridge inverter provided in the grid interconnection inverter unit share one arm. 2. The power supply apparatus according to claim 1, wherein the command value determined by the command changing means uses a predetermined change amount as an upper and lower limit value. The power supply apparatus according to claim 1, wherein a feed-forward control is performed by calculating a compensation amount to be compensated by the power saving unit from a disturbance superimposed by the isolated operation detecting means.

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