JP2015047024A - Power supply system including power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve continued operation of a system when a power converter is failed in the system in which a power generation system and a power storage system are connected in series.SOLUTION: The power supply system includes: the power generation system including a power generator and a first power converter connected to the power generator on the DC side; the power storage system including a plurality of second power converters mutually connected in series on the AC side and storage units respectively connected to the DC sides of the plurality of second power converters; and a control device for controlling the power generation system and the power storage system, where the power generation system and the power storage system are mutually connected in series. The power supply system further includes a bypass device connected to the power storage system in parallel.

Description

  The present invention relates to a power supply system including a power converter, and more particularly to a technique that is effective when applied to a system that supplies power by connecting generated power to a power system such as a solar power generation system.

  In recent years, the use of renewable energy has been promoted to improve the energy self-sufficiency rate. As one of the wings, there are solar power generation and wind power generation. They don't worry about exhausting energy sources and don't emit CO2 during power generation, but their output is unstable because they depend on the weather. Therefore, when expanding the use of renewable energy, a power storage device is indispensable in order to suppress fluctuations in power output. One of the power storage devices is a power storage system. For example, by combining solar power generation and a power storage system, fluctuations in output power of solar power generation can be suppressed.

  As disclosed in Non-Patent Document 1, conventionally, a solar power generation system and a power storage system are connected in series, and the output voltage of the solar power generation system and the power storage system is synthesized, thereby generating a harmonic of the alternating current of the entire system. There are systems that reduce distortion and supply power to the power system.

Real Time Digital Simulation of a novel Battery-integrated PV System for High Penetration Application, 2010 2nd IEEE International Symposium on Power Electronics for Distributed Generation Systems, p.786-790

  Non-Patent Document 1, however, because the power generation system and the power storage system are connected in series, even when power is not supplied from the power storage system, the power generated by the solar power generation system passes through the power converter of the power storage system, However, there is a problem that the power is consumed and the power cannot be supplied effectively.

  In a system in which a power generation system and a power storage system are connected in series, when power is not supplied from the power storage system when only the power generation system is operated, the power storage system is disconnected from the system, and only the solar power generation system is connected to the power system. The purpose is to interconnect, suppress loss generated in the power storage system, and effectively supply power to the power system.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  A power generation system having a power generation device, a first power converter connected to the power generation device on the DC side, a plurality of second power converters connected in series on the AC side, and the plurality of second powers In a power supply system including a power storage system having a power storage device connected to each DC side of the converter, a control device for controlling the power generation system and the power storage system, the power generation system and the power storage system connected in series, A power supply system comprising a bypass device connected in parallel with the power storage system.

  The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

  In the power supply system of the present invention, when power is not supplied from the power storage system, the power storage system is disconnected from the system, and only the photovoltaic power generation system is connected to the power system, and the loss generated in the power storage system is suppressed. It can be supplied effectively.

1 is a system block diagram illustrating a schematic configuration example of an entire power supply system according to the present invention. It is a circuit diagram which shows the connection structural example of the power converter of the power supply system of this invention. It is a circuit diagram which shows the connection structural example of the small power converter of the electric power supply system of this invention. It is a block diagram which shows the example of the control content of the control apparatus of the electric power supply system of this invention. It is a figure explaining the operation example of the electric power supply system of this invention, Comprising: It is a related figure which shows the relationship between solar radiation intensity and the control signal of the switch which is a bypass device. It is a figure explaining the operation example of the electric power supply system of this invention, Comprising: The relationship of the target voltage of an electric power supply system, an output voltage, and an output current, the control signal of a bypass device, the output voltage of a power converter and each small power converter FIG. In order to demonstrate PWM control of an Example, it is a related figure which shows the example of a relationship between the target voltage of a power converter device, a carrier wave, the switching pattern of a power converter, and the output voltage of a power converter. It is a figure explaining the operation example of the power supply system of this invention, Comprising: It is a related figure which shows the relationship between the target voltage of a power supply system, the control signal of a bypass apparatus, and the output voltage of a power converter. It is a figure explaining the operation example of the electric power supply system of this invention, Comprising: The relationship of the target voltage of an electric power supply system, an output voltage, and an output current, the control signal of a bypass device, the output voltage of a power converter and each small power converter FIG. It is a figure explaining the operation example of the electric power supply system of this invention, Comprising: The relationship of the target voltage of an electric power supply system, an output voltage, and an output current, the control signal of a bypass device, the output voltage of a power converter and each small power converter FIG.

  Hereinafter, in the embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments, but they are not irrelevant unless otherwise specified. Some or all of the modifications, details, supplementary explanations, and the like are related. Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 shows a power converter 101 as an embodiment of the power supply system of the present invention. The power conversion device 101 is a device that supplies power to the power system 105 via the reactor 104. The power conversion device 101 includes a solar power generation system 102, a power storage system 103, a control device 106, a measurement device 107, and a bypass device 119. In the present embodiment, the case where the power system 105 is a single phase will be described as an example, but the power system 105 may be a three-phase. In this case, the three-phase power storage system 103 provided corresponding to each of the three phases is linked to the three-phase power system 105 via the three-phase reactor.

  The bypass device 119 is means for electrically disconnecting or connecting the power storage system, and any form may be employed. For example, a switch is installed in a bypass path connecting both ends of the power storage system. A configuration in which the bypass is realized only by opening and closing the switch may be used, or a bypass state may be established by combining this with an operation in the power storage system.

  Reactor 104 has an effect of smoothing output voltages of synthesized power generation system 102 and power storage system 103 and suppressing harmonic components transmitted to the system. The solar power generation system 102 includes a solar panel 109, a capacitor 110, a power converter 111 that converts direct current and alternating current, and a diode 112 for preventing a current from flowing backward to the solar panel 109. The solar panel 109 and the capacitor 110 are connected in parallel, and a diode 112 is connected in series with the solar panel 109 between the solar panel 109 and the capacitor 110, and these are connected to the DC side terminal of the power converter 111. . In addition, the solar panel 109 shall be provided with the measuring device which measures the solar panel 109 electric current value in an output terminal.

  The power storage system 103 includes power storage devices 116 to 118 and small power converters 113 to 115 that convert direct current and alternating current. The power storage devices 116 to 118 are connected to the direct current side connection portions of the small power converters 113 to 115, respectively, and the small power converters 113 to 115 are connected in series at the alternating current side connection portion. In FIG. 1, a storage battery is described as an example of a power storage device, but another power storage device such as a capacitor may be used.

  The bypass device 119 is connected in parallel to the power storage system. As an example of the bypass device 119, a switch is used in FIG.

  The measurement device 107 in FIG. 1 measures the voltage value and current value of the power system 105 and transmits the measured voltage value data to the control device 106. FIG. 2 shows the configuration of the power converter 111. The power converter 111 includes a switching circuit 20, a DC connection unit 21, an AC connection unit 22, a control device 27, a smoothing capacitor 28, and a switch 29. The DC connection unit 21 includes a measuring device that measures the voltage and current on the DC side of the power converter 111, and transmits the measured voltage data and current data to the control device 27. The control device 27 transmits the acquired data to the control device 106.

  The switching circuit 20 includes switching elements 23a to 26a that are IGBTs (Insulated Gate Bipolar Transistors). In the present embodiment, the case where an IGBT is used as the switching elements 23a to 26a will be described as an example. However, other switching elements such as a MOSFET (Metal Oxide Field Effect Transistor) may be used.

  The switching circuit 20 includes a first leg configured by electrically connecting an emitter of the switching element 23a of the upper arm and a collector of the switching element 24a of the lower arm, and an emitter of the switching element 25a of the upper arm. A second leg constructed by electrically connecting the collector of the lower arm switching element 26a in series; the drains of the upper arm switching elements 23a and 25a; and the lower arm switching elements 24a and 26a. Is a single-phase full-bridge inverter circuit in which the first and second legs are electrically connected in parallel.

  Diodes 23b to 26b are provided between the collectors and emitters of the switching elements 23a to 26a, respectively.

  FIG. 3 shows the configuration of the small power converter 113. The small power converter 113 includes a switching circuit 30, a DC connection unit 31, an AC connection unit 32, a control device 37, a smoothing capacitor 38, and a switch 39. The DC connection unit 31 includes a measuring device that measures the voltage and current on the DC side of the small power converter 113, and transmits the measured voltage value and current value data to the control device 37. The control device 37 transmits the acquired data to the control device 106.

  The switch 39 is opened due to an overcurrent, and has a function of notifying the controller 37 that the switch 39 has been opened.

  The switching circuit 30 includes switching elements 33a to 36a that are MOSFETs. In the present embodiment, the case where MOSFETs are used as the switching elements 33a to 36a will be described as an example. However, other switching elements such as IGBTs may be used.

  The switching circuit 30 includes a first leg configured by electrically connecting a source of the upper arm switching element 33a and a drain of the lower arm switching element 34a in series, a source of the upper arm switching element 35a, A second leg configured to be electrically connected in series with the drain of the lower arm switching element 36a; the drains of the upper arm switching elements 33a and 35a; and the lower arm switching elements 34a and 36a. Is a single-phase full-bridge inverter circuit in which the first and second legs are electrically connected in parallel.

Parasitic diodes 33b to 36b are provided between the sources and drains of the switching elements 33a to 36a, respectively, due to the MOSFET structure. For this reason, it is not necessary to separately provide a diode between the drain and the source of the switching element.

  Hereinafter, control in the case where the power conversion apparatus 101 supplies constant power to the AC power system at normal time will be described.

  FIG. 4 shows an example of the control contents of the control device 106 in a block diagram. The control device 106 outputs the data and current of the output current value data of the solar panel 109 from the measurement device provided with the solar panel 109 and the voltage value measured from the measurement device of the DC side connection portion 21 of the power converter 111. Data obtained by measuring values, data obtained by measuring voltage values and current values from the measuring device of the AC side connection portion 22 of the power converter 111, data obtained by measuring voltage values and current values of the power system 105 from the measuring device 107, And the data which measured the voltage value from the measuring device of the direct current side connection part 31 of small power converters 113-115, the data which measured the current value, and the data which show the switching state of the switch 39 are acquired. Note that the data obtained by measuring the voltage value of the DC side connection portion 21 of the power converter 111 corresponds to the data obtained by measuring the voltage value at both ends of the capacitor 110.

  Hereinafter, each calculation is performed in each block based on the acquired data.

  The measurement data obtained by measuring the AC voltage and AC current of the power system 105 acquired from the measuring device 107 are input to the target voltage calculation block 401, and the target voltage Vm of the voltage output from the power converter 101 is calculated. This target voltage Vm is a target voltage waveform that the power converter 101 should output in order for the power converter 101 to supply power to the AC power system 105 via the reactor 104.

  The switching pattern generation block uses the data obtained by measuring the voltage values at both ends of the capacitor 110, the data obtained by measuring the current value obtained from the measuring device provided in the solar panel 109, and the target voltage Vm calculated by the target voltage calculation block 401. Input to 402 to generate a switching pattern Vu.

  Data obtained by measuring the target voltage Vm calculated by the target voltage calculation block 401, the switching pattern Vu calculated by the switching pattern generation block 402, and the voltage across the capacitor 110 are input to the output voltage pattern calculation block 403, and the power converter 111 The voltage waveform Ve to be output is calculated. Specifically, the output voltage V1 of the power converter 111 can be estimated by multiplying Vu generated by the switching pattern generation block 402 by data obtained by measuring the voltage values at both ends of the capacitor 110.

  The output voltage Ve of the power converter 111 estimated in the output voltage pattern calculation block 403 is differentiated from the target voltage Vm, and the voltage waveform is divided as the target voltage waveform Vb to be output by the power storage system that the small power converters 113 to 115 are responsible for. This is input to the block 405, where it is divided in the voltage direction and input to the correction pattern generation block 408.

  First, voltage waveforms Vs1 to Vs3 output from the small power converters 113 to 115 of the power storage system 103 are obtained by calculation. Since the small power converters 113 to 115 are electrically connected in series, the voltage waveforms Vs1 to Vs3 to be output by the small power converters 113 to 115 are added to the target voltage waveform Vb to be output by the power storage system. Corresponding stepped multilevel voltage. A specific dividing method for obtaining the individual voltages Vs1 to Vs3 is based on the voltage values Vba1 to Vba3 at both ends of each of the storage batteries 116 to 118, and the target voltage waveform Vb to be output by the power storage system is 3 in the voltage direction. To divide. Using these, the voltage waveforms of the small power converters 113 to 115 are obtained sequentially.

  First, in the small power converter 113, when the voltage value of the target voltage waveform Vb to be output by the power storage system is between 0 and less than Vba1, a rectangular wave having an amplitude of Vba1 in the positive voltage direction is generated. When the voltage value of the voltage waveform Vb is greater than −Vba1 and less than or equal to 0, the voltage waveform Vs1 of the small power converter 113 is generated by calculation assuming that a rectangular wave having an amplitude of −Vba1 is generated in the negative voltage direction. To do.

  Similarly, in the small power converter 114, when the voltage value of the target voltage waveform Vb to be output from the power storage system is between Vba1 and less than Vba1 + Vba2, a rectangular wave having an amplitude of Vba2 in the positive voltage direction is generated. When the voltage value of the voltage waveform Vb is greater than − (Vba1 + Vba2) and less than or equal to −Vba1, the voltage waveform Vs2 of the small power converter 114 is calculated assuming that a rectangular wave having an amplitude of −Vba2 is generated in the negative voltage direction. Generate with.

  Similarly, in the small power converter 115, when the voltage value of the target voltage waveform Vb to be output from the power storage system is between Vba1 + Vba2 and less than Vba1 + Vba2 + Vba3, a rectangular wave having an amplitude of Vba3 in the positive voltage direction is generated. When the voltage value of the voltage waveform Vb is greater than-(Vba1 + Vba2 + Vba3) and less than-(Vba1 + Vba2), the voltage waveform Vs3 of the small power converter 114 is assumed to generate a rectangular wave having an amplitude of -Vba3 in the negative voltage direction. Is generated by calculation.

  The output current of the solar panel 109, the voltage at both ends of the capacitor 110, the data of the voltage value and the current value measured by the measuring device of each AC side connection part 32 of the small power converters 113 to 115, and the small power converters 113 to Data indicating the open / close state of each of the switches 39 is input to the state diagnosis block 406. The state diagnosis block 406 is based on the solar radiation intensity estimated from the output current of the solar panel 109 and the voltage across the capacitor 110, or the voltage value and current value data measured by the measuring devices of the small power converters 113 to 115, respectively. The operation state of the small power converter is diagnosed and the state Sj is output.

  Here, the diagnosis of the operating state of the small power converter refers to diagnosing whether each of the plural small power converters is operating normally, or whether an element in the power converter is abnormal and has failed. It is. If the small converter is in a failure state, the small power converter corresponding to the failure is additionally diagnosed as a failure state that can be bypassed in the switching circuit using the switching element of the small converter. For example, when the switching elements 34a and 35a of the small power converter 113 have an open failure, the small power converter 113 cannot be bypassed by controlling the switching elements. Such a state of the switching element of the small power converter is estimated from the measurement data of the voltage value and the current value acquired from the measuring device of the AC side connection portion 32 of the small power converter and the open / closed state of the switch 39. .

  The bypass signal generation block 407 generates a control signal for controlling the opening / closing of the bypass device 119 using the state Sj diagnosed by the state diagnosis block 406. By this control signal, the bypass device 119 is closed at an appropriate timing, whereby the power storage system is disconnected, and only the photovoltaic power generation system is connected to the power system to supply power.

  Output voltage pattern Ve calculated by the output voltage pattern calculation block 403, voltage waveforms Vs1 to Vs3 to be output by the small power converters 113 to 115 divided by the voltage waveform division block, and the state Sj diagnosed by the state diagnosis block 406 are corrected patterns. By inputting to the generation block 408, the switching patterns of the power converter 111 and the small power converter are corrected.

  Specifically, when the solar radiation intensity is low, or when at least one or more small power converters cannot be bypassed using the switching elements of the small converters, the bypass device bypasses as described above. As a result, the power storage system is disconnected, and the solar power generation system alone is connected to the power system, so that efficient power transmission can be continued. The correction pattern Vq generated by the correction pattern generation block 408 is added to the switching pattern Ve of the power converter 111 to correct the output voltage of the power converter 111. This correction complements the voltage carried by the bypassed power storage system, and the voltage waveform output to the system by this complementary voltage approaches a sine wave. This correction can reduce harmonic distortion of the alternating current of the system.

  Next, in the case where all of the small power converters in which an abnormality has occurred are faults that can be bypassed using the switching elements, the small power converters 113 to 115, the power The switching pattern generation block 410 adds the correction pattern Vq to the switching pattern Vu generated by the switching pattern generation block 402 so that the converter 111 outputs a correction voltage. With this correction, the power converter 111 outputs a correction voltage for a voltage that cannot be output by the failed small power converter, so that an output waveform close to a sine wave is maintained, and harmonic distortion of the alternating current of the system can be reduced. . Correction patterns Vp1 to Vp3 are input to a switching pattern generation block 409 that generates a switching pattern of the small power converter so that only the small power converter corresponding to the failure can be bypassed. When there is one small power converter that is bypassed in the switching circuit, the correction pattern input to the switching pattern generation block 409 may be only Vp1 to Vp2. When there are two small power converters that are bypassed in the switching circuit, the input correction pattern may be only Vp1.

  If all small power converters are abnormal, even if all the small power converters can be bypassed in the switching circuit using switching elements, there will be no voltage contribution from the power storage system. Since power loss in the power storage system that can be reduced by the configuration of the embodiment occurs, it is desirable to bypass the storage battery system with a bypass device and disconnect from the system. However, a situation in which all the small power converters are connected by a bypass in the switching circuit for some reason, such as a malfunction of the bypass device, may be desirable from the viewpoint of power transmission continuity.

  The switching pattern generation block 409 generates a switching pattern output from the small power converter according to the correction pattern calculated by the correction pattern calculation block 408.

  The switching pattern generation block 410 inputs the switching pattern Vu generated by the switching pattern generation block 402 and the correction pattern generated by the correction pattern generation block 408 to the switching pattern generation block 410, and generates the switching pattern of the power converter 111. .

  The control device 106 sends the switching pattern of the power converter 111 generated by the switching pattern generation block 410 to the power converter 111 using communication means. The switching patterns of the small power converters 113 to 115 generated by the switching pattern generation block 409 are sent to the small power converters 113 to 115 using communication means, respectively.

  A method for controlling the bypass device according to the solar radiation intensity will be described.

  FIG. 5 shows the relationship between the control signal of the bypass device bypass device 119 and the solar radiation intensity. The upper graph shows the voltage waveform of the control signal of the bypass device 119, and the lower graph shows the solar radiation intensity. The upper graph shows voltage on the vertical axis and time on the horizontal axis. The lower graph shows solar radiation intensity on the vertical axis and time on the horizontal axis. For example, two threshold values of Eth_u and Eth_l are provided, and the bypass device 119 is controlled from the relationship between these threshold values and the solar radiation intensity. Specifically, when the solar radiation intensity is lower than Eth_l, the bypass device 119 is closed, the power storage system is disconnected, and the solar power generation system alone is connected to the power system. When the solar radiation intensity is higher than Eth_u, the bypass device 119 is opened and connected to the power system by a circuit connecting the solar power generation system and the power storage system.

  When the solar radiation intensity decreases, the voltage supplied by the power generation and supply system decreases, which is insufficient to supply a rectangular wave to the system that combines the output voltages of the solar power generation system 102 and the power storage system 103 and supplies them to the system. Therefore, there is a risk that it will be difficult to maintain the output in a waveform close to a sine wave. Moreover, if the solar radiation intensity | strength falls, the electric power loss which generate | occur | produces by passing a storage battery system will become large as a ratio with respect to the electric power transmitted to a system | strain. By performing bypassing of the bypass device and disconnecting the power storage system from the power supply system when the solar radiation intensity decreases, power loss due to the power storage system can be suppressed. At the same time, by appropriately changing the output waveform of the power converter 111, the generation of harmonics can be suppressed. Furthermore, even if the output of the solar power generation system is low, the allowable range of solar radiation intensity required to continue power transmission becomes wider by the amount of loss being suppressed, and the power transmission continuity of the solar power generation system can be improved. is there. As a method of determining the decrease in solar radiation intensity, two threshold values may be set as described above, or a single threshold value of solar radiation intensity is set, or an output value threshold value of the power generation system is set, It is also possible to perform bypass when the control device detects that the threshold value has been exceeded.

Furthermore, the correction voltage output by the power converter 111 so as to complement the output voltage of the storage battery system bypassed as described above is preferably a comb-like voltage in order to reduce harmonic distortion. The condition that the loss generated in the power converter 111 to generate such a comb voltage is lower than the loss generated by passing through the small power converters 11 to 115 is the solar radiation intensity that is a criterion for bypass determination. For example, the threshold value can be determined.

  Hereinafter, the voltage waveform output by each converter and the output current waveform of the power converter 101 according to the switching patterns of the power converter 111 and the small power converters 113 to 115 calculated by the control device 106 will be described.

  FIG. 6 shows the relationship between the output voltage and target voltage of the power conversion device 101 and the output current of the power converter, the output voltage of the power converter 111, and the output voltages of the small power converters 113 to 115 when the small power converter operates normally. (1 cycle). The vertical axis represents voltage (positive and negative), the horizontal axis represents time, and the output voltage Vout and target voltage (dotted line) Vm of the power converter 101, the output voltage V1 of the power converter 111, and the power converter 101 in order from the top. Output current Iout, output control signal of bypass device 119, output voltage V4 of small power converter 115, output voltage V3 of small power converter 114, and output voltage V2 of small power converter 113, respectively. It is assumed that the solar radiation intensity is greater than or equal to the threshold Eth_u.

  The target voltage (dotted line) Vm of the power converter 101 is calculated by the target voltage calculation block 401 shown in the block diagram of FIG.

  The output voltage Vout of the power conversion device 101 is a combined waveform of the output voltages V1 to V4 of the power converter 111 and the small power converters 113 to 115 that are electrically connected in series.

  The output control signal of the bypass device 119 generates a signal for controlling the bypass device 119 by the bypass signal generation block 407 from the operation state Sj of the small power converter diagnosed by the state diagnosis block 406 shown in the block diagram of FIG. .

  The output voltage V1 of the power converter 111 is generated by the switching circuit 20 of the power converter 111 by the switching pattern generated by the switching pattern generation block 410 shown in the block diagram of FIG. It is the generated output voltage waveform.

  The output voltage V2 of the small power converter 113 is operated by the switching circuit 30 generated by the switching pattern generation block 409 shown in the block diagram of FIG. 32 is an output voltage waveform generated in FIG.

  Similarly to the small power converter 113, the output voltages V3 and V4 of the small power converters 114 and 115 are also converted into small power converters by the respective switching patterns generated by the switching pattern generation block 409 shown in the block diagram of FIG. This is an output voltage waveform generated at each AC side connection by the operation of the switching circuits of the respective devices 114 and 115.

  As shown in FIG. 5, the output control signal of the bypass device 119 can output a logical value 1 so that the bypass device 119 performs bypass at times T5 to T6. In that case, also in the period from T11 to T12, the logic value 1 is output so that the bypass is performed in the same period as the period in which the bypass device 119 performs the bypass in the corresponding period from time 0 to T11. In this way, when the power supplied from the power supply system to the system is output only from the photovoltaic power generation system, the output control signal of the bypass device 119 outputs a logical value 1, and the bypass device is bypassed. Only the solar power generation system is connected to the grid.

  As for the output voltage V1 of the power converter 111, a rectangular wave having a positive voltage is generated at the AC connection unit 22 at times T4 to T7. In the period of time T11 to T12, the positive voltage is the same period (width of the same amplitude) and the same amplitude height (absolute value) as the positive voltage generated in the period of time 0 to T11. The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  As shown in FIG. 6, the output voltage V2 of the small power converter 113 generates a positive voltage rectangular wave at the AC connection portion 32 during the period of time T1 to T4, T5 to T6, and T7 to T10, and the time T4. A rectangular wave having a negative voltage is generated at the AC connection portion 32 during the periods of T5 and T6 to T7. In the period from time T11 to time T12, the positive voltage and the negative voltage generated in the period from time 0 to T11 have the same period (the same amplitude width) and the same amplitude height (absolute value), respectively, and the amplitude direction is the same. The reverse voltage is generated symmetrically.

  As shown in FIG. 6, the output voltage V <b> 3 of the small power converter 114 generates a rectangular wave having a positive voltage at the AC connection portion of the small power converter 114 in the period of time T <b> 2 to T <b> 4 and T <b> 7 to T <b> 9. In the period from the time T11 to the time T12, the positive voltage generated in the period from the time 0 to the time T11 has the same period (same amplitude width) and the same amplitude height (absolute value). The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  Similarly, as shown in FIG. 6, the output voltage V4 of the small power converter 115 generates a rectangular wave having a positive voltage at the AC connection portion of the small power converter 115 in the period of time T3 to T4 and T7 to T8. . In the period from the time T11 to the time T12, the positive voltage generated in the period from the time 0 to the time T11 has the same period (same amplitude width) and the same amplitude height (absolute value). The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  Since the power converter 111 and the small power converters 113 to 115 are electrically connected in series with each other, the output voltage Vout of the power converter 101 is as shown in FIG. 6 by adding these output voltages V1 to V4. In addition, a voltage close to a stepped sine wave corresponding to the target voltage Vm is output.

  The output current Iout of the power converter 101 has a waveform with little distortion because the output voltage V1 of the power converter 111 is a voltage close to a sine wave.

  The outline of PWM (Pulse Width Modulation) control will be described with reference to FIG. In FIG. 7, the vertical axis represents voltage, the horizontal axis represents time, and the target voltage Vm and carrier wave Vcr of the power conversion device 101, the switching pattern of the power converter 111, and the power converter 111 when performing PWM control in order from the top. A half cycle of the output voltage V1 is shown. In the PWM control, a switching pattern of the power converter 111 is generated using a carrier wave Vcr that is a triangular wave and a target voltage Vm. As shown in FIG. 7, the voltage values of the carrier wave Vcr and the target voltage Vm are compared, and when the target voltage Vm is larger than the carrier wave Vcr, a logical value 1 is generated, and conversely, the target voltage Vm is greater than the carrier wave Vcr. When the value is smaller, a switching value of the power converter 111 is generated by generating a logical value 0. By operating the switching circuit 20 of the power converter 111 using this switching pattern, the output voltage V1 of the power converter 111 as shown in FIG. 7 is generated. The generated output voltage V1 of the power converter 111 by PWM control changes the duty ratio of the voltage to generate a waveform that approximates the target voltage Vm of the power converter 101 with a rectangular wave. Regardless of the switching pattern, a waveform output so as to approximate the target voltage with a plurality of rectangular waves having the same peak voltage is expressed as a comb-like waveform.

  PWM control for outputting a comb-like waveform is used by the power converter 111 according to the situation. For example, when the bypass device 119 is bypassed when the solar radiation intensity is reduced or when any of the small power converters 113 to 115 cannot bypass the switching circuit, the power converter 111 is configured as shown in FIG. 0 to T12, that is, constant PWM control can be considered. As a result, a voltage close to a sine wave is output and harmonic components are suppressed. As another method, a rectangular voltage is output as usual between T4 to T5 and vice versa, and the PWM control is output only at the other part that complements the voltage that the power storage system was carrying until bypassed. It can also be considered. Thereby, although the harmonic component suppression effect is slightly reduced as compared with the case where all PWM control is performed, it is possible to suppress the power loss that occurs when the PWM control is performed.

  Further, when any one or more of the small power converters 113 to 115 are bypassed in the switching circuit, the bypass device 119 is bypassed at a timing at which the power converter 111 outputs a voltage that complements it. However, it is conceivable that the power converter 111 partially performs PWM control at that timing.

  In FIG. 8, when any of the small power converters 113 to 115 cannot be bypassed using the switching element of the small converter, or when the solar radiation intensity is low, the bypass device 119 is fixed in the bypass state, and the power converter 111 The relationship between the output voltage of the power converter 101, the target voltage, and the control signal to the bypass device 119 (one cycle) in the case where PWM control is continuously used in FIG.

  Voltage (positive and negative) is taken on the vertical axis, time is taken on the horizontal axis, and the target voltage (dotted line) Vm of the power converter 101, the control signal of the bypass device 119, and the output voltage V1 of the power converter 111 are respectively shown from the top. Show.

  The target voltage (dotted line) Vm of the power converter 101 is calculated by the target voltage calculation block 401 shown in the block diagram of FIG.

  The output voltage Vout of the power conversion device 101 is generated by PWM control. It is assumed that the carrier wave can be generated inside the switching pattern generation block 402 shown in the block diagram of FIG.

  The control signal of the bypass device 119 is generated by the bypass signal generation block 407 in FIG.

  As shown in FIG. 8, the output voltage V1 of the power converter 111 is time T1-T2, T3-T4, T5-T6, T7-T8, T9-T10, T11-T12, T13-T14, T15-T16, T17. At T18, a positive voltage having an amplitude (absolute value) with the same amplitude as the voltage value at both ends of the capacitor 110 is generated at the AC connection portion 22. In the period from time T19 to T20, the positive voltage is the same period (the same amplitude width) and the same amplitude height (absolute value) as the positive voltage generated in the period from time T1 to T18. The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  When the solar radiation intensity is low, specifically when the solar radiation intensity is lower than Eth_l, or when it is in a state in which it cannot be bypassed in the switching circuit using a switching element in any of the small power converters, the bypass device 119 As the control signal, a logical value 1 is output so that the control signal is linked to the grid only by the output of the solar sunlight power generation system in the period of time 0 to T16.

  In the power supply system of the present embodiment, the power storage system is composed of three small power converters 113 to 115. However, even when there are two or four small power converters, all the small power converters By having the bypass device 119 that simultaneously bypasses the converter, the effects as described above can be obtained. In such a configuration, when combining the electric power output from the power storage system and the photovoltaic power generation system, the switching patterns output from the small power converters are appropriately distributed in order to obtain a desired stepped waveform.

  In the power supply system of the present embodiment, the power generator is solar power generation, but the effect of the present embodiment can be obtained as long as the output that requires the power storage system connected in series is not stable. For example, when a wind power generator is connected to the power supply system of the present embodiment, a power converter that converts an AC voltage output from the wind power generator into a direct current is installed between the power converter 111 and the same as the present embodiment. Can be implemented.

  In the present embodiment, the control device 106 that controls the power generation system 102 and the power storage system 103, and the control device 27 and the control device 28 that control switching of each power converter and sensing of the periphery thereof are described separately. However, the role classification for each configuration is not limited to the classification of the explanation so far. In the description, the instruction between the control devices is not clarified. However, the control device 106 designates the type of switching control performed by the control device 27, and the control is performed by transmitting the sensor signal input to the control device 27. It is conceivable that the device 106 instructs the bypass device 119 to bypass.

  As described above, the power supply system according to the present embodiment uses the bypass device connected in parallel to the power storage system in the case where the small converter cannot be individually bypassed in the power storage system 103 or when the solar radiation intensity is low. It can be connected to the grid only by the output of the photovoltaic system. Therefore, in a system in which a photovoltaic power generation system and a power storage system are connected in series, even when the solar radiation intensity is low and the amount of power generation is small, power can be effectively supplied to the system. Further, even when the failed part cannot be bypassed in the power storage system, the power supply to the system can be continued.

In addition, when the power storage system is operating normally or when some of the small power converters are abnormal, when the power is supplied from the power generation system only to the system without the output from the power storage system, the bypass device 119 bypasses the system. By carrying out, it is possible to obtain a stabilizing effect by the power storage system at the timing of use, and at the same time, suppress power loss that occurs in the power storage system.

  In the second embodiment, an operation continuation method when a small converter breaks down will be described. In this embodiment, an operation continuation method and a harmonic distortion reduction method at the time of a failure that a small power converter can bypass in a switching circuit using a switching element of the small converter will be described.

  The configuration of the power supply system and its control flow are the same as in FIGS.

  First, the waveform will be described as a comparison with the present embodiment when the power converter 111 does not supplement the voltage of the small converter 115 bypassed in the switching circuit.

  FIG. 9 shows output voltages and target voltages of the power converter 101, the power converter 111, and the small power converters 113 to 115 when the small power converter 115 is bypassed by a switching element of the small converter due to a failure. (1 cycle).

  The vertical axis represents voltage (positive and negative), the horizontal axis represents time, and the output voltage Vout and target voltage (dotted line) Vm of the power converter 101, the output voltage V1 of the power converter 111, and the power converter 101 in order from the top. , Output voltage V2 of the small power converter 113, output voltage V3 of the small power converter 114, and output voltage V4 of the small power converter 115, respectively.

  The target voltage (dotted line) Vm of the power converter 101 is calculated by the target voltage calculation block 401 shown in the block diagram of FIG.

  The output voltage Vout of the power conversion device 101 is a combined waveform of the output voltages V1 to V4 of the power converter 111 and the small power converters 113 to 115 that are electrically connected in series.

  The output voltage V1 of the power converter 111 is generated by the switching circuit 20 of the power converter 111 by the switching pattern generated by the switching pattern generation block 410 shown in the block diagram of FIG. It is the generated output voltage waveform.

  The output voltages V2 and V3 of the small power converters 113 and 114 are switched by the switching patterns generated by the switching pattern generation block 409 shown in the block diagram of FIG. Is an output voltage waveform generated at each AC side connection by operating.

  The output voltage V4 of the small power converter 115 is generated by the switching pattern generation block 409 based on the state Sj generated by the state diagnosis block shown in the block diagram of FIG. It is the output voltage waveform of the bypass state generated in the AC side connection part by the switching circuit 30 operating.

  As shown in FIG. 9, the output voltage V <b> 1 of the power converter 111 generates a positive voltage rectangular wave at the AC connection unit 22 at times T <b> 4 to T <b> 7. In the period of time T11 to T12, the positive voltage is the same period (width of the same amplitude) and the same amplitude height (absolute value) as the positive voltage generated in the period of time 0 to T11. The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  As shown in FIG. 9, the output voltage V2 of the small power converter 113 generates a positive voltage rectangular wave at the AC connection portion 32 during the period of time T1 to T4, T5 to T6, and T7 to T10. A rectangular wave having a negative voltage is generated at the AC connection portion 32 during the periods of T5 and T6 to T7. In the period from time T11 to time T12, the positive voltage and the negative voltage generated in the period from time 0 to T11 have the same period (the same amplitude width) and the same amplitude height (absolute value), respectively, and the amplitude direction is the same. The reverse voltage is generated symmetrically.

  As shown in FIG. 9, the output voltage V3 of the small power converter 114 generates a rectangular wave having a positive voltage at the AC connection portion of the small power converter 114 in the period of time T2 to T4 and T7 to T9. In the period from the time T11 to the time T12, the positive voltage generated in the period from the time 0 to the time T11 has the same period (same amplitude width) and the same amplitude height (absolute value). The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  Since the small power converter 115 is in a bypass state due to a failure, the output voltage V4 has a voltage waveform having an amplitude of 0 (absolute value) at the AC connection portion of the small power converter 115 as shown in FIG. Will occur.

  Since the power converter 111 and the small power converters 113 to 115 are electrically connected in series with each other, the output voltage Vout of the power conversion device 101 is as shown in FIG. 9 by adding these output voltages V1 to V4. In addition, a stepped voltage corresponding to the target voltage Vm is output. Originally, the output voltage Vout of the power conversion device 101 has a voltage waveform close to a sine wave, but the small power converter 115 does not output a voltage in a bypass state using the switching element of the small converter due to a failure. The voltage waveform is not close to a wave.

The output current Iout of the power converter 101 has a waveform with a large distortion as shown in FIG. 9 because the output voltage V1 of the power converter 111 does not become a voltage close to a sine wave.

  Next, in the power supply system of the present embodiment, a waveform when the power converter 111 outputs power supplementing the output voltage of the small power converter bypassed in the switching circuit will be described.

  In FIG. 10, the power converter 101, the power converter 111, when the small power converter 115 is bypassed by using the switching element of the small converter due to a failure, and the correction voltage from the power converter 111 is added, The relationship (for 1 cycle) of the output voltage of small power converters 113-115 and a target voltage is shown.

  The vertical axis represents voltage (positive and negative), the horizontal axis represents time, and the output voltage Vout and target voltage (dotted line) Vm of the power converter 101, the output current Iout of the power converter 101, and the power converter 111 in order from the top. A correction pattern Vq added to the switching pattern, an output voltage V1 of the power converter 111, an output voltage V2 of the small power converter 113, an output voltage V3 of the small power converter 114, and an output voltage V4 of the small power converter 115, respectively. Show.

  The target voltage (dotted line) Vm of the power converter 101 is calculated by the target voltage calculation block 401 shown in the block diagram of FIG.

  The output voltage Vout of the power conversion device 101 is a combined waveform of the output voltages V1 to V4 of the power converter 111 and the small power converters 113 to 115 that are electrically connected in series.

  The correction pattern Vq added to the switching pattern of the power converter 111 is a correction pattern generated by the correction pattern generation block 408 shown in the block diagram of FIG. By inputting the correction pattern Vq generated by the correction pattern generation block 408 of FIG. 4 and the switching pattern generation block 410 generated by the switching pattern generation block 402, the switching pattern of the power converter 111 is generated.

  The output voltage V1 of the power converter 111 is generated by the switching circuit 20 of the power converter 111 by the switching pattern generated by the switching pattern generation block 410 shown in the block diagram of FIG. This is a generated output voltage waveform.

  The output voltages V2 and V3 of the small power converters 113 and 114 are switched by the switching patterns generated by the switching pattern generation block 409 shown in the block diagram of FIG. Is an output voltage waveform generated at each AC side connection by operating.

  The output voltage V4 of the small power converter 115 is generated by the switching pattern generation block 409 based on the state Sj generated by the state diagnosis block shown in the block diagram of FIG. It is the output voltage waveform of the bypass state generated in the AC side connection part by the switching circuit 30 operating.

  As shown in FIG. 10, the correction pattern Vq added to the switching pattern of the power converter 111 is a comb-like positive correction voltage applied to the AC connection portion 22 of the power converter 111 during the time T3 to T4 and the time T7 to T8. It is a correction pattern that generates a waveform. Similarly, in the period from time T11 to T12, the positive period is the same as the positive voltage generated by the power converter 111 in the period from time 0 to T11 (the same amplitude width) and the same amplitude height (absolute value). The correction pattern is such that a voltage (negative voltage) whose amplitude is opposite to that of the negative voltage is generated symmetrically to the positive voltage.

  As shown in FIG. 10, the output voltage V1 of the power converter 111 is a comb-like positive voltage waveform at times T3 to T4, a positive voltage rectangular wave at times T4 to T7, and a comb-like positive voltage at times T7 to T8. Are generated in the AC connection 22 respectively. In the period of time T11 to T12, the positive voltage is the same period (width of the same amplitude) and the same amplitude height (absolute value) as the positive voltage generated in the period of time 0 to T11. The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  As shown in FIG. 10, the output voltage V2 of the small power converter 113 generates a rectangular wave having a positive voltage at the AC connection portion 32 during the period from time T1 to T3, T5 to T6, and T8 to T10. A rectangular wave having a negative voltage is generated at the AC connection portion 32 during the periods of T5 and T6 to T7. In the period from time T11 to time T12, the positive voltage and the negative voltage generated in the period from time 0 to T11 have the same period (the same amplitude width) and the same amplitude height (absolute value), respectively, and the amplitude direction is the same. The reverse voltage is generated symmetrically.

  As shown in FIG. 10, the output voltage V3 of the small power converter 114 generates a rectangular wave having a positive voltage at the AC connection portion of the small power converter 114 in the period of time T2 to T3 and T8 to T9. In the period from the time T11 to the time T12, the positive voltage generated in the period from the time 0 to the time T11 has the same period (same amplitude width) and the same amplitude height (absolute value). The reverse voltage (negative voltage) is generated symmetrically with the positive voltage.

  Since the small power converter 115 is in a state using a switching element of the small converter due to a failure, the output voltage V4 has a high amplitude at the AC connection portion of the small power converter 115 as shown in FIG. A voltage waveform with (absolute value) 0 is generated.

  Since the power converter 111 and the small power converters 113 to 115 are electrically connected in series with each other, the output voltage Vout of the power conversion device 101 is as shown in FIG. 10 by adding these output voltages V1 to V4. Is output.

  Since the output current Iout of the power converter 101 corrects the output voltage V1 of the power converter 111, the distortion of the output current Iout of the power converter 101 shown in FIG. The distortion of the output current Iout becomes smaller.

  As described above, in the present embodiment, the state where the small power converter 115 is abnormal and bypassed in the switching circuit has been described, but the other small power converter 113 or 114 or a plurality of them are bypassed in the circuit. It is possible to become. In that case, two countermeasures are given as examples.

  Consider a situation where not the small power converter 115 but the small power converter 114 fails and is bypassed in the switching circuit. In the first countermeasure, the switching pattern output from the small power converter 115 in FIG. 6 and the switching pattern output from the small power converter 114 are switched. As a result, the small power converter 115 outputs the output voltage V3, the small power converter 114 is bypassed, and the output becomes zero voltage. As a result, an abnormality occurs in the small power converter 115 in this embodiment, and the waveform is the same as when the circuit is bypassed, and the output voltage of the power converter 111 outputs the same complementary power as in the previous example. Will do. Even when the small power converter 113 fails, it can be dealt with by appropriately switching the sharing of the output voltage pattern with the small power converter 115. In the first coping method, the comb voltage output to be complemented by the power converter 111 is only the voltage V4 that is the least frequent and short period, so that the loss of comb voltage generation is minimized. And is efficient. Even in a state where a plurality of small power converters are bypassed, the small power converters may be appropriately connected between the small power converters so that the power converter 111 may complement a combination of switching patterns with the least frequency and a short period. Switch patterns.

  As a second countermeasure, when the small power converter 114 fails and is bypassed in the switching circuit, the power converter 111 supplements a voltage corresponding to the output voltage V4 of FIG. That is, the power converter 111 outputs a comb-like voltage corresponding to V4 during the period of T2 to T4 and T7 to T10 in FIG. At the same time, since the bypass device 119 is bypassed between T2 and T9, the output voltage of the storage battery system becomes zero. Even when the small power converter 113 and the small power converter 114 are abnormal at the same time and the two small power converters are bypassed in the circuit, the power converter 111 corresponds to T2 to T4 and T7 to T10. The same complementary voltage may be output during the reverse voltage period. Further, when the small power converter 113 is bypassed, the power converter 111 outputs a comb voltage during T1 to T4, T7 to T10 and the corresponding reverse voltage. In the first countermeasure, there is a disadvantage that the planned management of storage battery consumption becomes complicated when switching the switching pattern between small power converters on a case-by-case basis according to the failure. Then, since the normal small power converter is operated as it is, such a disadvantage is eliminated.

  These countermeasures may be adopted in combination so that the loss is minimized in accordance with the number of small power converters constituting the power supply system and the number of small power converters that are individually bypassed. desirable.

  In the power supply system of this embodiment, each small power converter is described on the condition that it can be bypassed in the switching circuit using a switching element. As a result, it is not necessary to newly add means for bypassing individual power converters, and an efficient power supply system with good power transmission continuity can be realized with only a bypass device that bypasses all storage battery systems. Yes.

The configuration of the present embodiment is advantageous in terms of cost particularly in a system having a large number of small power converters, but when the conversion efficiency is more important than the cost, the AC side terminals of the individual small power converters are individually bypassed. A bypass device may be installed. In that case, the failed small power converter is individually bypassed regardless of whether or not it can be bypassed in the circuit, and the power converter 111 supplements the corresponding voltage. While the complementary voltage is being output, the bypass device 119 that bypasses the entire storage battery system performs bypass in order to suppress loss caused by passing through the storage battery system, as in the present embodiment.

  A power generation system operation method using the power supply system as described in the first and second embodiments will be described.

  Since the photovoltaic power generation system is a target for investment and the total power generation is directly linked to the return on investment, the continuity of power generation is very important. For this reason, it is desirable to repair immediately when a problem occurs so that power generation can be continued in the most efficient state. However, since solar power generation systems are constructed to be scattered in large quantities at various scales, there are cases where it cannot be immediately addressed due to personnel issues. In addition, since maintenance costs are labor-intensive, if the opportunity loss caused by a failure does not exceed the maintenance cost, the failure may be left until the next major failure occurs, and the total power generation may decrease accordingly. It is done. The failure may be, for example, a failure of a switching element of a converter or deterioration of a storage battery.

  The high-efficiency power supply system having the power storage system according to the first and second embodiments has a configuration that provides optimum operation according to various types of abnormality occurrences that can occur without increasing the initial investment amount. Thereby, the power generation opportunity loss caused by the failure can be suppressed to a minimum range according to the part / scale of the failure. At the same time, the frequency of maintenance situations decreases, so the maintenance frequency and cost can be reduced. In addition, since the output waveform of the power converter 111 is partially switched to a comb pattern, the efficiency is maintained to the maximum, and the power quality supplied to the system does not deteriorate even in an operation state including an abnormality. You can reduce the urgency you have to do. Furthermore, since the operation can be continued with a desirable waveform output in which harmonics are suppressed even in a state where the power storage system is completely disconnected, the fault tolerance regarding the storage battery system is high.

  As an operation method that effectively exhibits the characteristics of the power supply system that suppresses the generation opportunity loss and the maintenance cost as described above, when an abnormality occurs in the power storage system, the power transmission is not stopped. 2. Bypassing the location where an abnormality has occurred using the method described in 2, switch control appropriately, and continue power transmission to the system. In addition, the control device 106 does not immediately give a display indicating the necessity of repair, but continues to operate while containing the abnormality until a certain condition is reached.

  In order to perform the above operation method, the control device 106 of the power supply system 101 has a function of calculating a power generation opportunity loss or a converter power loss caused by a switching pattern switched in response to the abnormality that has occurred. Specifically, the power supplied from the power supply system to the system is measured and stored from the voltage and current values measured at the AC side of the power converter 111 and the power storage system. After the control device 106 detects an abnormality in the power storage system and the bypass corresponding to the abnormality is performed, from the switching pattern information corresponding to the bypass state of which small power converter is performing the bypass, or From the voltage measurement values on the DC side of the power converter 111 and the small power converters 113 to 115, the power output that should be obtained when there is no abnormality in the power storage system at that time, or should be obtained when the abnormality is repaired The power output is estimated and stored from the coefficient set in advance in association with the generating unit or the learning data during normal operation. The power generation opportunity loss amount is integrated and stored from the difference between the actual power output and the power output that should be obtained.

  The control device 106 uses the data related to the calculated power generation opportunity loss amount and the information related to the abnormality determined in the state diagnosis block 406 to calculate a future loss prediction, and the corresponding abnormality input in advance in the form of a table. It is displayed on the display screen along with the repair costs at the occurrence location. Further, the control device 106 may compare the loss prediction and the repair cost, determine the time for repairing the location where the abnormality has occurred, and display it on the display device. As a repair time determination method, for example, a parameter of 0.5 is set in the control device 106 in advance, and the judgment to perform maintenance is determined before the opportunity loss predicted amount exceeds 0.5 times the predicted repair cost. Maintenance personnel can perform maintenance based on the displayed information. The power supply apparatus has a function of determining a period during which operation is continued in a state where there is an abnormality detected by the control apparatus 106, and can be operated based on the determination.

  The calculation described above and the screen display need not be performed by the control device 106 on-site of the power supply system, but may be performed, for example, by a server in a remote management center where maintenance personnel reside. In that case, the control device 106 has a function of transmitting data related to the power generation opportunity loss amount to the management center together with information on the abnormality determined in the state diagnosis block 406, and the management center server performs the calculation and display described above. It has an electronic computer and a display device for performing. The server of the management center has a function to determine the priority for the power supply system that needs to be maintained early based on the information on the loss of power generation opportunity and the location of the abnormality received from multiple power supply systems. May be. Furthermore, the server may have a function of determining the order of performing maintenance of the power supply system based on the determined priority. In the power supply systems according to the first and second embodiments, the location where an abnormality has occurred, the bypass method at that time, and the output pattern of the converter are clearly associated with each other, so the power generation opportunity according to the bypass status and the output pattern of the power supply system There is also an advantage that it is easy to estimate the amount of loss.

  As described above, the power supply system of the present embodiment outputs a complementary voltage from the photovoltaic power generation system when the small power converter of the power storage system has a failure that can be bypassed using the switching element of the small converter. The operation of the system can be continued while reducing the harmonic distortion of the output current that increases due to the failure of the small power converter.

The power supply system of each embodiment described above includes a solar panel 109 that is a solar power generation device, a power converter 111 that is a first power converter connected to the solar panel 109 on the DC side, Small power that is a photovoltaic power generation system 102 having a capacitor 110 connected in parallel between the optical panel 109 and the DC side of the power converter 111, and a plurality of second power converters connected in series on the AC side Converter 113, 114, 115, power storage system 103 having power storage devices 116, 117, 118 connected to the DC side of small power converters 113, 114, 115, respectively, power converter 111, and small power converter 113 , 114, and 115, and controls the voltage generated on the AC side of the power converter 111 and the small power converters 113, 114, and 115. The power converter 101, which is a power supply system that combines the voltage generated on the side and supplies power to the system via the reactor 104, has a bypass device connected in parallel to the power storage system Supply system. With such a configuration, in a system in which the photovoltaic power generation system and the power storage system are connected in series, the operation of the system can be continued when the power converter fails. Furthermore, harmonic distortion of the output current of the system can be reduced.

DESCRIPTION OF SYMBOLS 20 Switching circuit 21 DC connection part 22 AC connection part 23a-26a Switching element 22b-25b Diode 27 Control apparatus 28 Smoothing capacitor 29 Switch 30 Switching circuit 31 DC connection part 32 AC connection part 33a-36a Switching element 33b-36b Parasitic Diode 37 Control device 38 Smoothing capacitor 39 Switch 101 Power conversion device 102 Solar power generation system 103 Power storage system 104 Reactor 105 Power system 106 Control device 109 Solar panel 110 Capacitor 111 Power converter 112 Diodes 113 to 115 Small power converter 116 to 118 Power storage device 119 Bypass device

Claims (15)

A power generation system, and a power generation system having a first power converter connected to the power generation apparatus on the DC side;
A plurality of second power converters connected in series on the alternating current side, and a power storage system having power storage devices respectively connected to the direct current sides of the plurality of second power converters,
A control device for controlling the power generation system and the power storage system;
In the power supply system in which the power generation system and the power storage system are connected in series,
A power supply system comprising a bypass device connected in parallel with the power storage system.
The power supply system according to claim 1,
The power supply system, wherein the control device controls the bypass device to perform bypass when the power supplied from the power supply system to the system is only the output of the power generation system.
The power supply system according to claim 2,
The control device controls the power generation system to output a voltage that complements the output voltage of the power storage system so that the power supplied to the grid approaches a sine wave when the bypass device performs bypass. A power supply system characterized by performing.
The power supply system according to claim 3, wherein
The power supply system, wherein the complementary output voltage is a comb-like voltage.
The power supply system according to claim 1,
The first power converter has a function of switching between rectangular wave output and PWM control output,
The control device controls the first power converter to switch to PWM control in a state where the bypass device performs bypass.
The power supply system according to any one of claims 1 to 5,
The control device bypasses the bypass device when it detects a solar radiation intensity that is lower than a set first threshold value or when it detects an output of the power generation device that is lower than a set second threshold value. A power supply system characterized by performing control.
The power supply system according to any one of claims 1 to 5,
The control device calculates a first power loss generated when the first converter generates a comb voltage, calculates a second power loss generated by passing the storage battery system, When it is determined that the second loss power exceeds the first loss power, a control for performing bypass of the bypass device is performed.
The power supply system according to any one of claims 1 to 5,
The control device is in a state where an abnormality has occurred in one or more of the plurality of second power converters and cannot be bypassed in a switching circuit in any of the second power converters in which the abnormality has occurred In this case, the power supply system is configured to perform control to perform bypass of the bypass device.
The power supply system according to claim 1,
The control device performs control to individually bypass the second power converter in which the abnormality has occurred in the power storage system when an abnormality has occurred in one or more of the plurality of second power converters. A power supply system characterized by performing.
The power supply system according to claim 1,
When the abnormality occurs in one or more of the plurality of second power converters, the control device performs control to bypass in the switching circuit in all of the second power converters in which the abnormality has occurred. Power supply system characterized by
The power supply system according to claim 10, wherein
The control device controls the power generation system to output a voltage that complements the output voltage of the second power converter that is bypassed in the switching circuit so that the power supplied to the system approaches a sine wave. A power supply system characterized by
The power supply system according to claim 11, wherein
The control device performs control to perform bypass of the bypass device when the power generation system is in a state of complementing the output of the second power converter that is bypassed in the switching circuit. Power supply system.
A power generator,
A first power converter connected to the power generator on the DC side;
A plurality of power storage devices;
A second power converter connected to each of the power storage devices on the DC side;
In the power supply system operation method in which the first power converter and the second power converter are connected in series on the AC side,
A method for operating a power supply system, characterized in that when the solar radiation intensity decreases or when an abnormality occurs in the second power converter, the second power converter is all bypassed.
The power supply system operation method according to claim 13,
When bypassing the second power converter,
A method of operating the power supply system, wherein the control method of the first power converter is switched.
A method of operating a power supply system,
The power supply system includes a power generation device, and a power generation system including a first power converter connected to the power generation device on a direct current side,
A plurality of second power converters connected in series on the alternating current side, and a power storage system having power storage devices respectively connected to the direct current sides of the plurality of second power converters,
A control device for controlling the power generation system and the power storage system;
A bypass device connected in parallel with the power storage system,

The power generation system and the power storage system are connected in series,
When an abnormality occurs in the power storage system,
The output pattern of the first power converter is set so as to bypass the location where the abnormality occurs in the power storage system in units of the second power converter and complement the output of the bypassed second power converter. Switching,
A method for operating a power supply system, wherein a power generation opportunity loss amount is calculated from the bypass state information or the output pattern information, and based on the calculated power generation opportunity loss amount, a period during which operation is continued in the presence of the abnormality is determined.