JP2007236193A - Power supply including system interconnection inverter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply including a system interconnection inverter capable of properly supplying surplus power to a false load that fluctuates every moment with a simple equipment configuration, as well as capable of suppressing an influence to electromagnetic interference, without impairing distorted wave ratio of output voltage/output current. <P>SOLUTION: A power supply system includes a system interconnection inverter 13 for reverse converting DC power to AC power, and supplying AC power to a load 17 connected to a system power supply 20, a false load 21 connected to the load in parallel via a power element 22, circuits 23, 24 for detecting voltages of the system power supply, and electric currents that flow out of/into the system power supply, a controller 15 for turning on/off the power element according to voltages and currents detected by the circuits, a computing portion 29 for computing power flow based on voltages and currents detected by the circuits, and a storage device 31 for storing power flow data computed by the computing portion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device including a grid-connected inverter, for example, a DC power source such as a solar cell or a fuel cell, or a DC power source formed by rectifying AC power generated from a gas turbine generator or a wind power generator, It is related with the power supply device containing the grid connection inverter which transforms the voltage of this and supplies the alternating current power reversely converted to the load connected to the commercial alternating current system power supply (henceforth a system power supply).

  In recent years, small-scale power generation facilities such as solar cells, fuel cells, and gas turbine generators are becoming widespread. In these power generation facilities, DC power generated by solar cells, fuel cells, or the like, or DC power obtained by rectifying AC power generated by a gas turbine generator, a wind power generator, etc., is converted into a DC / DC converter, In many cases, a transformer is transformed by a chopper circuit or the like, and is converted back to AC power by an inverter to supply power to a load. In such a case, the load is connected to the system power supply, and when power is not supplied from the power generation facility or when it is insufficient, power is supplied from the system power supply.

  In a power generation facility including a grid-connected inverter that reversely converts such DC power into AC power and supplies power to a load connected to the grid power supply, various regulations are provided because it is connected to the grid power supply. ing. One of them is the restriction of restricting reverse power flow. An example of this regulation is “to prevent the flow of active power (tidal current) from the premises of the power generation facility to the system power supply side from occurring in the bank of the distribution substation”. That is, all the active power generated by the power generation facility is supplied to the line load in the premises where the power generation facility exists, and the active power is restricted from flowing out to the system power source side.

  By the way, the required power of the line load in the power generation facility varies from time to time. On the other hand, the power generation capacity of the power generation facility is determined by the sunshine conditions for solar cells, for example, and the generated power cannot immediately follow the required power of the line load. For this reason, when the required power of the line load is lower than the generated power, surplus power is generated, and the surplus generated power is directed to the system power supply side, which is a so-called reverse power flow. Therefore, a method is generally adopted in which the generated power is kept approximately constant, a pseudo load (for example, a power resistor such as a heater) is provided, and the surplus power is absorbed by the pseudo load in accordance with fluctuations in the line load (for example, (See JP 2000-320401 A and JP 2002-281672 A).

However, since the line load changes from moment to moment, it cannot be predicted in advance. In practice, the magnitude of the pseudo load includes manufacturing errors and the like, and varies depending on the environment such as temperature and humidity. And, it is not always easy to accurately supply surplus power other than that consumed by the line load to the pseudo load among the power generation outputs that are generated at a constant pace.
In addition, if a thyristor or the like is used as a power element for controlling the opening and closing of the pseudo load, and the power element is controlled linearly at the energization angle, the output voltage or output current waveform of the inverter is distorted and THD (Total Harmonic Distortion) is generated. The standard value may be exceeded.
Similarly, when a device such as a half-bridge inverter is used, there is an adverse effect of generating a noise voltage (noise), a filter needs to be attached, and there is a problem that the price increases.

  The present invention has been made in view of the above-described circumstances, and can easily supply surplus power that varies from moment to moment to a pseudo load with a simple equipment configuration, and can also provide a distortion wave rate of output voltage and output current. It is an object of the present invention to provide a power supply device including a grid interconnection inverter that can suppress the influence on the electromagnetic interference without damaging it.

  A power supply apparatus including a grid interconnection inverter according to the present invention includes a grid interconnection inverter that reversely converts DC power into AC power and supplies the AC power to a load connected to the grid power supply, and a power element in the load. Through the pseudo load connected in parallel, the voltage of the system power supply, the circuit for detecting the current flowing into and out of the system power supply, and the power element based on the voltage and current detected by the circuit A control unit that turns on / off, a calculation unit that calculates a power flow based on the voltage and current detected by the circuit, and a storage device that stores data of the power flow calculated by the calculation unit It is characterized by.

  Here, the arithmetic processing detects a system voltage value and a current value flowing in and out from the system power source to the load side by a circuit that detects the system voltage and current installed on the load and system power source side, and the system voltage value The power value flowing in and out from the system power supply to the load side by the current value is calculated at a constant cycle such as one cycle or half cycle of AC, and the calculated power value of a fixed cycle such as one cycle or half cycle of AC is further calculated. The state value of the power flow is calculated by sequentially accumulating. As for the calculation of the power value, it is preferable to perform an integral calculation between zero-cross points of one AC cycle or half cycle, but the power value may be calculated from a peak value, for example. Also, the calculation cycle does not necessarily have to be one AC cycle or half cycle, and can be any fixed cycle. For example, the AC cycle may be two cycles or three cycles. Then, the accumulated value (state value) of the calculation of the power value in the fixed period is set to a pseudo load by turning on the power element after a predetermined level, for example, the next period or an arbitrary time after becoming zero or less. Supply power.

  As a result, it is possible to accurately grasp the power consumption state of the load that changes from moment to moment, and to supply surplus power to the pseudo load accurately with a simple equipment configuration. For example, various power switching elements such as an SSR (solid state relay), a relay, or a thyristor can be used as the power element. Moreover, it is possible to accurately prevent a so-called reverse power flow in which the active power flows out to the system power supply side only by providing a simple integration / addition means or the like by a program such as a microcomputer as the arithmetic unit. Further, a control cycle such as an AC cycle or a half cycle does not impair the distortion wave rate of the output voltage / output current. Moreover, it is possible to suppress the influence on electromagnetic interference.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same function, and the duplicate description is abbreviate | omitted.
FIG. 1 shows a schematic configuration of a power supply apparatus including a grid interconnection inverter according to an embodiment of the present invention. The DC power source 11 is a DC power source such as a solar cell or a fuel cell, or a DC power source obtained by rectifying the AC output of a gas turbine generator. Since the output voltage of the DC power supply 11 is generally low, it is boosted to a voltage sufficient to form an AC voltage of the system power supply by the DC / DC converter 12 or the like, and this boosted DC voltage is supplied to the inverter 13. Is done. When the output voltage of the DC power supply 11 is high, the voltage is stepped down as necessary.

  The inverter 13 includes a power switching element. The power switching element is on / off controlled by, for example, a pulse width modulation (PWM) signal supplied from the controller 15, and AC power reversely converted from DC power is output from its output terminal. Is output. Since the output voltage waveform of the inverter 13 is formed by a pulse width modulation (PWM) signal, it contains a large amount of harmonic components. For this reason, the harmonic component is removed by the filter 16, and the sine wave voltage of the inverter output is supplied to the load line 18 connected to the load 17 connected to the system power supply.

  Here, the power generation and power supply facilities from the DC power supply 11 to the load 17 are arranged on the premises of the power generation facility installer. The load line 18 to which the load 17 is connected is connected to a system power supply 20 outside the power generation facility installer. Therefore, for example, in a time zone where the DC power source 11 such as a solar battery does not generate power, power is supplied to the load facility 17 by power transmission from the system power source 20 side. Further, even when the generated power amount of the DC power supply 11 is lower than the required power amount of the load facility 17, a part of the power consumed by the load facility 17 is sent from the system power source 20 side.

  By the way, when the generated power amount of the DC power source 11 exceeds the required power amount of the load facility 17, so-called power sale may be performed in which surplus power is sent to the system power source 20 side. There may be cases where no reverse flow is allowed. The grid interconnection inverter device of this embodiment is suitable when no such reverse power flow is observed. That is, when the generated power amount of the DC power supply 11 exceeds the required power amount of the load 17, surplus power out of the inverter output power is supplied to the pseudo load 21 via the power element 22.

  Here, as the pseudo load 21, a device such as a battery charger or a flywheel, or a power resistor such as a heater may be used. That is, in the case of a battery charger or the like, surplus power can be stored as power energy, and in the case of a heater or the like, power energy is converted into heat energy by supplying a load current to the power resistor, and the surroundings of the power resistor The surplus power can be absorbed by heating the water or the like disposed in the. As the power element 22, various power switching elements such as an SSR (solid state relay), a thyristor, or a relay are used. By turning on the power element 22, surplus power of the inverter output is supplied to the pseudo load 21, and by turning off the power element 22, the supply of power to the pseudo load 21 is cut off.

  The power element 22 is preferably turned on / off between the zero cross points every half cycle or one cycle so as not to impair the distortion wave rate (THD) of the output voltage / output current waveform of the inverter. In addition, during the control every half cycle, in order not to output a DC component, control is performed so that positive half waves or negative half waves are not output continuously, and overall positive half waves and negative half waves are output. Control each output to be balanced. If the waveform distortion wave rate (THD) can be ignored, it is possible to perform on / off control at an arbitrary fixed time interval without considering the period of zero crossing or the like.

  A reverse power flow flowing from the load 17 side to the system power supply 20 side is detected by the current detector 23 and the voltage detector 24. The current detector 23 is connected to the current sensor circuit 25 and inputs the detected current value to the controller 15. The voltage detector 24 is connected to the voltage sensor circuit 26 and similarly inputs the detected voltage value to the controller 15. The current detector 23 is arranged at a connection part to the system power supply and detects a current input to and output from the system power supply. The voltage detector 24 is disposed on the output side of the filter 16 and detects the voltage of the system power supply.

  Then, the controller 15 calculates the detected current value and voltage value at regular intervals such as one cycle of AC or half cycle, so that the power value flowing into and out of the system power supply 20 and the load 17 side is calculated by the controller 15. Detected. At this time, the power flowing from the system power supply 20 side to the load line 18 side is a forward power flow, and the power flowing from the load line 18 side to the system power supply 20 side is a reverse power flow. Therefore, it is possible to detect the magnitude of the so-called reverse power flow that flows from the load line 18 side to the system power supply 20 side from this calculation result.

  FIG. 2 shows a configuration example of a control device that supplies surplus power to the pseudo load. In this embodiment, an SSR (solid state relay) 22 a is used as a power element that controls the supply of power to the pseudo load 21 connected in parallel to the load 17. The controller 15 includes a power calculation unit 28 that performs arithmetic processing on signals input from the current sensor circuit 25 and the voltage sensor circuit 26 and detects power flowing into and out of the system power supply side from the load side. As power elements, various power switching elements such as relays and thyristors can be used instead of SSR (solid state relay).

  The power detected by the power calculation unit 28 is input to the calculation unit 29, and the detected power is calculated at regular intervals such as one cycle of AC or half cycle, so that the power flow at that time, so-called reverse power flow The magnitude (power value) of is detected. Then, the power of the pseudo load 21 is calculated based on the accumulated power value (the power flow state value) obtained by adding (subtracting) the power value for each fixed period such as one AC cycle or half cycle by the calculation unit 29. A control unit 30 for generating a control signal for turning on / off the element 22a is provided. Here, the calculation unit 29 and the control unit 30 perform calculation of the power detected by the power calculation unit 28 every fixed period such as one AC cycle or half cycle, and accumulates and accumulates each cycle. The power element 22a is turned on and electric power is supplied to the pseudo load 21 in the next period when the value becomes a predetermined level, for example, zero or less. Accordingly, at this time, the pseudo load 21 absorbs all or a part of the generated power of the inverter, the sum of the required power of the pseudo load and the load 17 exceeds the power supplied by the inverter, and the shortage flows from the system power source 20 to the forward power flow. Supplied as

  That is, when a reverse power flow occurs, the magnitude of the reverse power flow with the power element 22 turned off is accumulated for each period, and this state value (accumulated value) is a constant value (for example, the pseudo load 21). When the power element 22 is turned on, the output power of the inverter can be absorbed by the pseudo load by turning on the power element 22, and the load 17 has a forward power flow corresponding to the accumulated value of the reverse power flow from the system power supply. Can be supplied. Therefore, on average, reverse power flow can be canceled by forward power flow, and reverse power flow can be prevented from occurring on the system power supply side.

  The controller 15 is configured by a microcomputer or the like, and the power calculation unit 28, the calculation unit 29, and the control unit 30 are all configured as logical calculation means provided inside the microcomputer. And since a calculating means only adds the output value of a power calculating part for every minute time, it is realizable by a very simple program process. Further, the controller 15 includes a storage unit 31 including a storage device such as a memory for storing power flow data calculated by the calculation unit 29, and an output unit 32 for outputting the data to a display unit. Similarly, the controller 15 includes a selection unit 33 that selects ON / OFF of the power flow control.

Next, a specific operation example will be described with reference to FIG. As described above, the operations of the power calculation unit and the calculation unit are performed based on one AC cycle or half cycle of the system power supply. That is, in the 50 Hz area, one period is 20 msec, and in the 60 Hz area, it is 16.67 msec. The power value is calculated for each period or half period, and the calculation result is added (subtracted). Based on the calculated value (state value of power flow), processing such as output of the control unit is performed. The example shown in FIG. 3 shows the addition / subtraction (accumulation) result of the calculation value (power value) in the calculation unit every 20 msec and the output control signal to the power element in the control unit. Here, T ₁ , T ₂ ,... Are each 20 msec.

In this example, when the generated power of the DC power supply 11 is 1 kW and the pseudo load is also 1 kW, the load is changed from ₁ kW to 800 W at time T ₁ . Then, the initial value as e.g. 500W of system power accumulated value (state value) is given at time T _1. In this case, since the power generation output is 1 kW and the required power of the load is 800 W, a reverse power flow of 200 W occurs when the pseudo load is off. Therefore, at time _{T 2,} the system power accumulated value is 300W (500W-200W) next, at time _{T 3,} the system power accumulated value is 100W (300W-200W). In this way, at the time _{T 4,} the system power accumulated value (state value) -100W (negative), and the control unit 30 at the next time _{T 5} outputs the ON signal to the power element 22a. At this time, all of the 1 kW power generated by the inverter is absorbed by the pseudo load 21, and the forward power flow 800 W is supplied to the load 17 from the system power supply 21 side.

For this reason, the accumulated value of the system power at this time is 700 W (−100 W − (− 800 W)). Then, at time T ₆ through T _9, for control signals of the power element 22a in the control unit 30 are both OFF, the dummy load is not powered in the meantime, the reverse flow state of 200 W. Therefore grid power accumulated value is 500W at _{T 6.}

Next, the accumulated power value is 300 W at time T ₇ , the accumulated power value is 100 W at T ₈ , and the accumulated power value is −100 W at T ₉ . Accordingly, an ON signal is formed for the power elements in the next time T _10. That is, at this time point, the accumulated value 800 W of the reverse power flow in the periods T ₆ , T ₇ , T ₈ , and T ₉ is canceled by the forward power flow in the period T ₁₀ . It will not occur. _Then, the _{T 10} after the cycle _T 6 _{through T 10} are repeated.

  Therefore, in the arithmetic unit 29, when the accumulated value turns negative by accumulating (subtracting) the power value of the reverse power flow from the initial value, the control unit 30 causes the power element in the next cycle. An ON signal is supplied to 22 so that power equivalent to the generated power is absorbed by the pseudo load. As a result, when viewed on average, the accumulated value of reverse power flow and the accumulated value of forward power flow are automatically balanced to prevent the occurrence of reverse power flow to the grid power source viewed from the average value. . Then, for example, 20 msec or 16.67 msec, or the magnitude of the reverse power flow is detected by calculation every half cycle, and this is sequentially added and subtracted (accumulated), and the forward current corresponding to this is pseudo-loaded. Since the power is formed with the power on, the surplus power of the generated power can be accurately supplied to the pseudo load corresponding to the required power of the load that varies from moment to moment, and the reverse power flow as a whole does not occur Can do.

  In the above, for simplification, the grid power, inverter output, pseudo load, and load size are all expressed as integers. However, the grid power is actually calculated in finer units by the voltage / current sensor. Since the power value is accumulated and added and subtracted, the power flow can be accurately calculated as a result. Therefore, even when the manufacturing error of the pseudo load or the load fluctuates every moment, surplus power can be accurately supplied to the pseudo load.

  In the above example, the control unit 30 determines ON / OFF of the power element on the condition that the accumulation result of the accumulated value of the calculation unit 29 is smaller than zero. However, it is also possible to set a predetermined set value such that the hysteresis determined based on zero instead of zero is set to be positive or negative.

  Here, the pseudo load 21 generally selects a load capacity slightly larger than the inverter rated output when designing the hardware. For example, when the inverter rated output is 1 kW, a 1.2 kW heater is selected as a pseudo load. If the user's power consumption during normal use is known in advance, the pseudo load capacity may be selected accordingly.

By changing the capacity of the pseudo load according to the situation of the installation site, it is possible to cope with the case where the inverter output is different without changing the control method.
Further, by setting the capacity of the pseudo load in advance by the input means, the power consumption of the pseudo load can be adjusted by the on / off pattern of the power element.

  Further, it is preferable that a circuit for detecting a current flowing into and out of the pseudo load is added and a set value of power consumed by the pseudo load can be input by a setting unit such as a touch panel, in addition to the capacity of the pseudo load. As a result, the user comprehensively considers when selling power is advantageous in terms of cost, or when it is advantageous in terms of cost to supply power to a pseudo load and convert it into heat energy such as hot water, for example. Then you can choose. Further, by setting the power consumption value of the pseudo load by the setting means, it is possible to perform power supply control to the pseudo load in accordance with the power consumption setting value.

Furthermore, in addition to the contents described above, by setting the power sale and the supply to the pseudo load for each time zone, control the power sale and the supply to the pseudo load according to the time zone such as day and night, for example. It is also possible to do.
The power flow data calculated by the calculation unit 29 is stored in a storage device 31 such as a memory, and the grid power flow can be displayed on a display device such as an LED by data processing means such as a digital filter as will be described later. In addition, by outputting the stored power flow data to an external device via the output unit 32, the power flow status before and after the occurrence of the failure can be used as a reference for repair work, or the user can check the power flow status. Therefore, it can be used as a reference for predicting the economic effects of electricity sales or reverse power flow.

In addition, by outputting the power flow data calculated by the calculation unit 29 to the external device by signal or communication, the external host device not only outputs the grid-connected inverter device but also the entire power flow including the load. I can grasp.
In addition, for example, by outputting information on reverse power flow or power consumption of a pseudo load to an external host device such as a power generation system, the above-mentioned set capacity of the pseudo load is input from the external host device via communication or contact. It is also possible to perform control based on the setting.
In addition, when the power is supplied from a micro gas turbine, fuel cell, etc., the external host device can adjust the power supply based on the power flow data, so that it can be economically operated to meet the load-side requirements. become.

  For example, in the above example, the power flow has a reverse power flow of 200 W each time except for the period when the power device is turned on from the previous power-on to the current power-on. The numerical value 200W is smoothed by a moving average method or the like, and can be calculated as a reduction command value of the supplied power. According to the supply power reduction command value 200W, the external host device performs adjustment control to lower the supply power from 1 kW to 800 W at a relatively slow speed, so that the inverter output and the load are finally balanced and no reverse power flow occurs. Can be.

  Further, when the inverter output and the load are balanced, for example, when the load increases by 100 W, the power flow becomes 100 W, which is a forward flow. At that time, the power element is naturally turned off. Therefore, the forward current value of 100 W is smoothed by a moving average method or the like, and can be calculated as an increase command value of the supplied power. The external host device increases the supplied power from 800 W to 900 W at a relatively slow speed and performs adjustment control, and finally the inverter output can be balanced with the load under the condition that no reverse power flow occurs. Here, care must be taken so that the inverter output does not exceed the maximum output of 1 kW. By performing adjustment control of the supplied power up and down according to the above-described method, the output of the power supply device is finally balanced with the load side, and operation with high economics becomes possible.

  Further, the control for turning on / off the pseudo load can be selected by the selection unit 33. Of course, this control is performed when reverse power flow and power selling are not permitted, but it may be preferable to perform this control even when power selling is permitted. According to the result of comparison based on advantages and disadvantages such as economic effects, the selection unit 33 performs the sale of power and the case where the electrical energy is accumulated or converted into thermal energy by supplying power to the pseudo load. There is an advantage that the user can set this control on / off.

FIG. 4 shows a configuration example of a control system according to another embodiment of the present invention. 2 differs from the control system shown in FIG. 2 in that the SSR (solid state relay) is used as the power element in the embodiment shown in FIG. 2, whereas the thyristor 22b is used in this embodiment. Other configurations are exactly the same. The thyristor 22b is turned on during the ignition period according to the angle command value of the ignition angle. For this reason, for example, in the example shown in FIG. 3, by supplying an ON signal such as T ₅ , T _10, etc., all sections are fired in each period, and all the sections are turned on. Also in this embodiment, it is shown in FIG. 2 and FIG. 3 that by integrating and calculating the power input / output amount to the system power source for each period, the surplus power can be absorbed accurately in the pseudo load and the reverse power flow can be prevented. This is the same as the embodiment shown.

  In some cases, the amount of power supplied to the pseudo load can be adjusted by controlling the firing angle. That is, when the maximum power consumption of the pseudo load is 1 kW, the generated power is 1 kW, and there is no load, all firing is adopted, and when the load power is 200 W, for example, the firing angle corresponding to that is controlled. Thus, the pseudo load power consumption can be changed to 800 W without changing the heater capacity, which is the absorbed power amount of the pseudo load. In this way, by using the thyristor 22b capable of controlling the firing angle as the power element 22, the power capacity of the pseudo load is adjusted to correspond to the load power and the total power consumption is adjusted to match the generated power. Is possible.

  In each of the above two embodiments, the power element and the pseudo load are connected between the output filter and the system power source or the load. If the power element and the pseudo load are connected to another place, for example, if the power element and the pseudo load are connected before the output filter, the harmonics included in the inverter output directly flow into the pseudo load. This has the adverse effect of generating noise voltage (noise) for the entire power supply device.

Furthermore, a circuit for detecting the inflow / outflow current is added not only to the system power supply 20 side but also to the load side 17, the inverter side 13, and the pseudo load side 21, thereby reversing the power consumption of the pseudo load. It is possible to more easily recognize the power flowing.
In addition, the said embodiment described the one aspect | mode of the Example of this invention, Of course, a various deformation | transformation Example is possible, without deviating from the meaning of this invention.

  As described above, according to the present invention, the inverter controller calculates the power flow to the system power supply every fixed period such as one AC cycle or half cycle, and calculates the constant cycle such as one AC cycle or half cycle. By providing a calculation unit that sequentially adds power values and a power element that controls the supply of power to the simulated load based on the calculation result, the simulated load is designed to prevent reverse power flow on the grid power supply side on average. The amount of power supplied can be controlled. As described above, the arithmetic unit and the control unit can be configured by simple program processing such as a microcomputer, and the power element is a very simple power switching element such as SSR (solid state relay) or a relay or thyristor. Therefore, it is possible to perform extremely economical and stable control for preventing reverse power flow. At the same time, by performing one-cycle or half-cycle control separated by zero crossing, the distortion wave rate (THD) is not impaired in the output voltage / current of the grid-connected inverter. In addition, it is possible to provide a device capable of suppressing the influence on electromagnetic interference.

  The present invention transforms the voltage of a DC power source such as a solar cell or a fuel cell, or a DC power source formed by rectifying AC power generated from a gas turbine generator or a wind power generator, and connects it to a commercial AC grid power source. It can be used for a power supply device including a grid-connected inverter that supplies reverse-converted AC power to a load.

FIG. 1 is a block diagram showing an outline of a power supply apparatus including a grid interconnection inverter according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration example of the controller in FIG. FIG. 3 is a time chart showing an operation example of the calculation unit and the control unit of the controller shown in FIG. FIG. 4 is a block diagram showing a modification of FIG.

Claims (8)

A grid-connected inverter that reverse-converts DC power into AC power and supplies the AC power to a load connected to a grid power supply;
A pseudo load connected in parallel to the load via a power element;
A circuit for detecting a voltage of the system power supply and a current flowing into and out of the system power supply;
Based on the voltage and current detected by the circuit, a control unit for turning on and off the power element;
A computing unit for computing a power flow based on the voltage and current detected by the circuit;
A power supply device comprising: a storage device for storing power flow data calculated by the calculation unit.   The power supply device according to claim 1, wherein the arithmetic unit calculates the data of the power flow from an average value of the power flow when the power element is off.   The power supply apparatus according to claim 1, further comprising means for outputting the data of the power flow stored in the storage unit to an external device by a signal or communication.   The power supply apparatus according to claim 3, further comprising an input unit configured to input a command value of power supply determined by the external device based on the data of power flow by a signal or communication.   The power supply apparatus according to claim 1, further comprising a setting unit configured to set power consumption consumed by the pseudo load.   The power supply apparatus according to claim 1, further comprising a setting unit configured to set whether or not to perform control for turning on / off the power element.   The power supply apparatus according to claim 6, wherein the setting unit is configured to be able to set whether or not to perform control to turn on / off the power element for each time zone.   A power generation system comprising the power supply device according to claim 1 and a generator.

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