JP2019103160A - Power conversion system - Google Patents

Abstract

To provide a power conversion system capable of performing a control in accordance with a failure part.SOLUTION: A power conversion system 100 comprises: a plurality of power conversion circuits 1; a control part 20; and a failure detection part 21. The plurality of power conversion circuits 1 are electrically connected in parallel between a pair of first terminals and a pair of second terminals, and convert an input voltage into a desired voltage. The control part 20 controls the operation of the plurality of power conversion circuits 1. The failure detection part 21 detects the failure occurrence in any one of a plurality of first measurement parts 5, a second measurement part 6, and the plurality of power conversion circuits 1 from measurement values of the first measurement parts and the second measurement parts. The plurality of first measurement parts 5 correspond to the plurality of power conversion circuits 1 one by one and measure currents flowing through the power conversion circuits 1. The second measurement part 6 measures the current flowing through the pair of first terminals.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates generally to power conversion systems, and more particularly to power conversion systems that include multiple power conversion circuits.

  Patent Document 1 discloses an example of a conventional power converter. In the power conversion device of Patent Document 1, three DC-DC converters (power conversion circuits) are connected in parallel to the rear stage of the smoothing capacitor. A load is connected to the output of the parallel-connected DC-DC converter through three output current sensors that respectively measure the output current. The control means controls three DC-DC converters from the output current measured by the three output current sensors.

  The control means includes a DC-DC converter failure determination means. The DC-DC converter failure judging means judges the failure of the three DC-DC converters from the output currents measured by the three output current sensors. In this power converter, the DC-DC converter in which the output current is equal to or higher than the output current failure threshold when any of the output currents detected by the output current sensor is equal to or higher than a predetermined output current failure threshold. Is determined to be a failure.

JP, 2015-95970, A

  In Patent Document 1, for example, even when a failure occurs in an output current sensor (first measurement unit), a failure of a DC-DC converter (power conversion circuit) whose output current is measured by the output current sensor It is determined that For this reason, in patent document 1, there existed a problem that it was difficult to perform control according to the actual fault location (output current sensor or DC-DC converter).

  This indication is made in view of the above-mentioned reason, and aims at providing a power conversion system which enables performing control according to a fault part.

  A power conversion system according to an aspect of the present disclosure includes a plurality of power conversion circuits, a control unit, and a failure detection unit. The plurality of power conversion circuits are electrically connected in parallel between the pair of first terminals and the pair of second terminals, and convert the input voltage into a desired voltage. The control unit controls the operation of the plurality of power conversion circuits. The failure detection unit is any of the plurality of first measurement units, the second measurement unit, and the plurality of power conversion circuits from the measurement values of the plurality of first measurement units and the measurement values of the second measurement unit. To detect if a failure has occurred. The plurality of first measurement units are provided in a one-to-one correspondence with the plurality of power conversion circuits, and measure the current flowing through the corresponding power conversion circuits. The second measurement unit measures the current flowing through the pair of first terminals.

  A power conversion system according to another aspect of the present disclosure includes a plurality of power conversion circuits, a control unit, and a failure detection unit. In the plurality of power conversion circuits, the first capacitors provided in each are electrically connected in series between the pair of first terminals, and the second capacitors provided in each are connected in series between the pair of second terminals. . Each of the plurality of power conversion circuits converts a voltage input through one of the first and second capacitors into a desired voltage and outputs the voltage from the other of the first and second capacitors. The control unit controls the operation of the plurality of power conversion circuits. The failure detection unit is any of the plurality of first measurement units, the second measurement unit, and the plurality of power conversion circuits from the measurement values of the plurality of first measurement units and the measurement values of the second measurement unit. To detect if a failure has occurred. The plurality of first measurement units are provided in one-to-one correspondence with the plurality of power conversion circuits, and respectively measure the voltage between the first capacitors of the corresponding power conversion circuits. The second measuring unit measures a voltage between the pair of first terminals.

  The present disclosure has the advantage that control can be performed according to the failure location.

FIG. 1 is a circuit diagram of the power conversion system of the first embodiment. FIG. 2 is a circuit diagram of a power conversion circuit in the above power conversion system. FIG. 3 is a flowchart showing the operation of the above power conversion system. FIG. 4 is a flowchart showing the operation of the power conversion system same as the above, and is a continuation of FIG. FIG. 5 is a circuit diagram of the power conversion system of the second embodiment. FIG. 6 is a circuit diagram of a power conversion circuit according to a modification.

  The embodiments described below are only one of various embodiments of the present invention. Embodiments of the present invention are not limited to the following embodiments, but may include others. In addition, various modifications can be made according to the design and the like as long as the following embodiments do not deviate from the technical idea according to the present invention.

(1) Embodiment 1
(1.1) Outline FIG. 1 is a system configuration diagram of a power conversion system 100 according to the present embodiment.

  As shown in FIG. 1, the power conversion system 100 includes a plurality of (N; N is an integer of 2 or more, where N = 3) power conversion circuits 11 to 13 and a processing device 2. ing. The processing device 2 includes a control unit 20, a failure detection unit 21, a storage unit 22, and a notification unit 23. The plurality of power conversion circuits 11 to 13 are electrically connected in parallel between the pair of first terminals and the pair of second terminals.

  In the present embodiment, the power conversion system 100 is electrically connected between the DC power supply 8 and the intermediate bus 9. In power conversion system 100, one of the pair of first terminals and the pair of second terminals is a pair of power supply side terminals 31, 32 electrically connected to DC power supply 8, and the other is an intermediate bus 9 are a pair of bus side terminals 41 and 42 electrically connected to 9. Here, it is assumed that the pair of first terminals is the pair of power supply side terminals 31 and 32, and the pair of second terminals is the pair of bus side terminals 41 and 42.

  As shown in FIG. 1, a plurality of first measurement units 51 to 53 are provided to correspond to the plurality of power conversion circuits 11 to 13 one by one. Each of the plurality of first measurement units 51 to 53 measures the current flowing through the corresponding power conversion circuits 11 to 13. More specifically, each of the plurality of first measurement units 51 to 53 measures the current flowing between the corresponding power conversion circuits 11 to 13 and the pair of first terminals (a pair of power supply side terminals 31 and 32) Do.

  In addition, a second measurement unit 6 is provided on an electric path between the pair of first terminals (a pair of power supply side terminals 31 and 32) and the DC power supply 8. The second measurement unit 6 measures the current flowing through the pair of first terminals (the pair of power supply side terminals 31 and 32). The second measurement unit 6 is, for example, a current sensor that is provided integrally with the DC power supply 8 and is used to adjust the magnitude of the output current.

  In the power conversion system 100, each of the plurality of power conversion circuits 11 to 13 converts the input voltage into a desired voltage. The control unit 20 controls the operations of the plurality of power conversion circuits 11 to 13 using the measurement results (measurement values) of the plurality of first measurement units 51 to 53. The failure detection unit 21 uses the measurement values of the plurality of first measurement units 51 to 53 and the measurement values of the second measurement unit 6 to generate the plurality of first measurement units 51 to 53, the second measurement unit 6, and the plurality of measurement units. It is detected which of the power conversion circuits 11 to 13 has a failure.

  In the power conversion system 100 according to the present embodiment, which one of the plurality of first measurement units 51 to 53, the second measurement unit 6, and the plurality of power conversion circuits 11 to 13 has a failure caused by the failure detection unit 21 Are identified. Therefore, in the power conversion system 100 of the present embodiment, the control unit 20 can cause the plurality of power conversion circuits 11 to 13 to perform an operation according to the failure location identified by the failure detection unit 21.

(1.2) Details The configuration of the power conversion system 100 of the present embodiment will be described using FIGS. 1 and 2. In the following description, when each of the plurality of power conversion circuits 11 to 13 is not distinguished, it is referred to as the power conversion circuit 1, and when each of the plurality of first measurement units 51 to 53 is not distinguished, it is referred to as the first measurement unit 5. Moreover, below, the 1st measurement part 5 (1st measurement part 51-53) is called the 1st current measurement part 5 (1st current measurement part 51-53), and the 2nd measurement part 6 is a 2nd current measurement part. It is called six. The “terminal” may not necessarily have a substance as a component for connecting a wire, and may be, for example, a lead of an electronic component or a part of a conductor included in a circuit board.

  As shown in FIG. 1, the power conversion system 100 according to the present embodiment includes a plurality of (here, three) power conversion circuits 11 to 13, a processing device 2, and a notification device 230. The processing device 2 includes a control unit 20, a failure detection unit 21, a storage unit 22, and a notification unit 23. Moreover, the power conversion system 100 of this embodiment is provided with a pair of power supply side terminals 31 and 32, and a pair of bus side terminals 41 and 42. Furthermore, the power conversion system 100 is provided with a plurality of (in this case, three) first current measurement units 51 to 53 and a second current measurement unit 6.

  A DC power supply 8 is electrically connected to the pair of power supply side terminals 31 and 32. A DC voltage is input from the DC power supply 8 between the pair of power supply side terminals 31 and 32. Hereinafter, the DC voltage input between the pair of power supply side terminals 31 and 32 is referred to as “input voltage V1”. Here, although the storage battery is assumed as the DC power supply 8, it is not limited to this. The DC power supply 8 may be a solar cell, a fuel cell or the like.

  The pair of bus side terminals 41 and 42 are electrically connected to the intermediate bus 9. For example, an inverter circuit (DC-AC inverter circuit) 91 is electrically connected to the intermediate bus 9. Therefore, the DC voltage output from the pair of bus terminals 41 and 42 is input to the inverter circuit 91. Hereinafter, the voltage output from between the pair of bus side terminals 41 and 42 is referred to as "output voltage V2". The inverter circuit 91 is, for example, a full bridge inverter including four switching elements, and converts a DC voltage output from the power conversion system 100 into an AC voltage. The alternating voltage output from the inverter circuit 91 is supplied to a load 92.

  The load 92 is a device or a power system that operates by receiving an AC voltage, and is here a power system. When the load 92 is a power system, the inverter circuit 91 is controlled such that a current synchronized with the phase of the system voltage of the power system flows.

  The power conversion system 100 of the present embodiment constitutes a power conditioner together with an inverter circuit 91. The power conditioner performs grid-connected operation in a steady state, converts DC power input from the DC power supply 8 into AC power, and outputs the AC power to the power system. In addition, at the time of abnormality such as a power failure of the electric power system, the power conditioner performs a self-sustaining operation in which the disconnecting device is opened and AC power is output in a state of being disconnected from the electric power system.

  In the power conversion system 100 of the present embodiment, the plurality of power conversion circuits 1 are electrically connected in parallel between the pair of power supply side terminals 31 and 32 and the pair of bus side terminals 41 and 42. The plurality of power conversion circuits 1 boost and output the input voltage V1 so that the output voltage V2 is stabilized. Here, "the output voltage V2 is stabilized" means that the variation of the voltage value of the output voltage V2 is suppressed so that the voltage value of the output voltage V2 does not significantly vary, and the output voltage V2 is constant In addition to the state maintained at the voltage V.sub.2, the state where the output voltage V2 falls within a certain range including a constant voltage. For example, if the load 92 is a power system, the power conversion circuit 1 boosts the input voltage V1 such that the output voltage V2 is equal to or higher than the reference voltage (that is, the output voltage V2 is higher than the system voltage). . The reference voltage is, for example, 300 to 330 [V].

  In the present embodiment, each of the plurality of power conversion circuits 1 is a non-insulated step-up DC-DC converter. As shown in FIG. 2, the power conversion circuit 1 includes a pair of input terminals T11 and T12, two capacitors C1 and C2, an inductor L1, a diode D1, a switching element Q1, and a pair of output terminals T21 and T22. And have.

  The capacitor C1 is electrically connected between the pair of input terminals T11 and T12. The capacitor C2 is electrically connected between the pair of output terminals T21 and T22. The first end of the inductor L1 is electrically connected to the high potential side input terminal T11, and the second end is electrically connected to the anode of the diode D1. The cathode of the diode D1 is electrically connected to the output terminal T21 on the high potential side. The switching element Q1 is formed of an enhancement type n-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The source of the switching element Q1 is electrically connected to the low potential side input terminal T12 and the output terminal T22. The drain of the switching element Q1 is electrically connected to the second end of the inductor L1 and the anode of the diode D1. The switching element Q1 is turned on / off by a control signal supplied from the control unit 20. In other words, the switching element Q1 is controlled by the control unit 20. The switching element Q1 is not limited to a MOSFET, and may be another semiconductor switch element such as an IGBT (Insulated Gate Bipolar Transistor) or a bipolar transistor.

  The pair of input terminals T11 and T12 in the power conversion circuit 1 are electrically connected to the pair of power supply side terminals 31 and 32 in the power conversion system 100, respectively. Therefore, a DC voltage (input voltage V1) is input from the DC power supply 8 between the pair of input terminals T11 and T12. The pair of output terminals T21 and T22 in the power conversion circuit 1 are electrically connected to the pair of bus side terminals 41 and 42 in the power conversion system 100, respectively. Power conversion circuit 1 converts a DC voltage (input voltage V1) input between a pair of input terminals T11 and T12 into a desired DC voltage (output voltage V2), and converts the DC voltage after conversion into a pair of output terminals Output from T21 and T22 to the intermediate bus 9 (inverter circuit 91).

  The plurality of first current measurement units 51 to 53 are provided in one-to-one correspondence with the plurality of power conversion circuits 11 to 13. Specifically, the first current measurement unit 51 corresponds to the power conversion circuit 11, the first current measurement unit 52 corresponds to the power conversion circuit 12, and the first current measurement unit 53 corresponds to the power conversion circuit 13. Each of the plurality of first current measurement units 5 has a function of detecting the current flowing through the corresponding power conversion circuit 1.

  As shown in FIG. 1, each of the plurality of first current measurement units 5 is provided between the input terminal T11 on the high potential side of the corresponding power conversion circuit 1 and the branch point P1. The branch point P1 is a point branched from the power supply side terminal 31 on the high potential side into a path through which current flows to the power conversion circuit 1 and a path through which the other power conversion circuit 1 flows. That is, in the present embodiment, each of the plurality of first current measurement units 5 measures the current flowing from the power supply side terminal 31 (or the branch point P1) on the high potential side to the corresponding power conversion circuit 1 .

  As shown in FIG. 1, the second current measurement unit 6 is provided between the pair of power supply side terminals 31 and 32 and the DC power supply 8. The second current measurement unit 6 has a function of detecting the current flowing through the pair of power supply side terminals 31 and 32. Specifically, the second current measurement unit 6 is provided between the output terminal on the high potential side of the DC power supply 8 and the power supply side terminal 31 on the high potential side. That is, in the present embodiment, the second current measurement unit 6 measures the current flowing from the DC power supply 8 to the power supply side terminal 31 (or the branch point P1) on the high potential side.

  Each of the plurality of first current measurement units 5 and second current measurement units 6 is configured using, for example, a current transformer, and outputs a signal according to the measurement value (effective value of current) to the processing device 2 .

  The processing device 2 acquires the measurement results (measurement values) of the plurality of first current measurement units 5 and the second current measurement unit 6, and refers to the acquired measurement values to switch the switching elements of the plurality of power conversion circuits 1 Control Q1.

  The processing device 2 mainly includes, for example, a microcomputer (microcomputer) or a DSP (digital signal processor), and executes various processes by executing a program stored in a memory. The processing device 2 implements the functions of the control unit 20 and the failure detection unit 21 by executing a program. The program may be stored in advance in a memory, may be provided through a telecommunication line, and may be stored and provided in a storage medium.

  The storage unit 22 of the processing device 2 is, for example, a semiconductor memory such as a ROM (Read Only Memory) or an EEPROM (Electrically Erasable Programmable Read Only Memory), and stores various information.

  The notification unit 23 of the processing device 2 is an interface for communication, and is used to transmit a signal including various information to the notification device 230. The notification unit 23 may be connected to the notification device 230 by wire and transmit a signal to the notification device 230 by wire, or, for example, wirelessly signal the notification device 230 using near-field wireless communication or the like. May be sent.

  The control unit 20 controls the operation of the plurality of power conversion circuits 1 by providing a control signal to each switching element Q1 of the plurality of power conversion circuits 1 and switching on / off. This control signal is a PWM (Pulse Width Modulation) signal. The control signal is not limited to the PWM signal, and may be, for example, a PFM (Pulse Frequency Modulation) signal or a PAM (Pulse Amplitude Modulation) signal.

  Specifically, control unit 20 performs control such that output voltage V2 approaches the target voltage and, for each of the plurality of power conversion circuits 1, the measurement value of corresponding first current measurement unit 5 approaches the target value. ing. The above target values of the plurality of power conversion circuits 1 may be a common value or different values. For example, when the control signal is a PWM signal, the control unit 20 realizes the above control by adjusting the duty of the control signal supplied to the plurality of power conversion circuits 1.

  The failure detection unit 21 measures the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement from the measurement values of the plurality of first current measurement units 5 and the measurement values of the second current measurement unit 6. It is detected whether or not a failure has occurred in any of the units 6. In addition, the failure detection unit 21 determines, based on the measurement values of the plurality of first current measurement units 5 and the measurement values of the second current measurement unit 6, the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second It is specified in which of the current measurement units 6 a failure has occurred. A method in which the failure detection unit 21 detects the occurrence of a failure, and a method for identifying which of the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement unit 6 has a failure Will be described in the section “(1.3) Operation of Failure Detection Unit”.

  When the failure detection unit 21 detects that a failure has occurred in any of the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement unit 6, the failure of the control unit 20 occurs. Report occurrences. Further, the failure detection unit 21 determines which of the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement unit 6 has a failure (that is, a failure point), The control unit 20 is notified. Further, the failure detection unit 21 causes a failure in any of the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement unit 6 in the notification device 230 via the notification unit 23. Notify what you are doing.

  When receiving the notification of the failure point from the failure detection unit 21, the control unit 20 controls (changes) the operation of the plurality of power conversion circuits 1 according to the failure point. The method of controlling (changing) the operation of the plurality of power conversion circuits 1 when the notification of the failure point is received from the failure detection unit 21 is described in “(1.4) Operation at the time of failure detection”. I will explain in the column.

  The notification device 230 includes, for example, a device such as a display that visually displays information. The notification device 230 displays, for example, character information indicating a failure point based on the signal received from the notification unit 23. However, the configuration of the notification device 230 is not limited to this. For example, the notification device 230 includes a plurality of light sources (for example, LEDs: Light Emitting Diodes) respectively associated with the plurality of power conversion circuits 1, the plurality of first current measurement units 5, and the second current measurement units 6. The light source corresponding to the failure point may be turned on. Further, the notification device 230 is not limited to a device that visually displays information, and may be a device that aurally outputs information by voice or buzzer sound, for example.

(1.3) Operation of Failure Detection Unit Next, a method of detecting the occurrence of a failure and a method of specifying a failure location will be described with reference to the flowcharts of FIGS. 3 and 4. In the description of this section, the numbers of the plurality of power conversion circuits 1 and the plurality of first current measurement units 5 are represented by “N (N is an integer of 2 or more)”. In addition, N power conversion circuits 1 are appropriately described as power conversion circuits 1 n (n is an arbitrary integer of 1 to N) to distinguish them from one another, and the N first current measurement units 5 are They are described as the current measurement units 5 n (n is an arbitrary integer of 1 to N) to distinguish them from each other.

  When the operation is started, the failure detection unit 21 first determines whether or not the measurement unit is in a failure state. The measurement unit failure state is a state in which a failure occurs in any one of the plurality of first current measurement units 51 to 5N and the second current measurement unit 6.

Failure detection unit 21, the measurement values from the plurality of first current measuring unit 51~5N _I 11 _{~I 1N} were respectively obtained, it acquires the measured value _{I 2} from the second current measuring unit 6 (S1). Then, the failure detection unit 21 calculates the total value of the acquired measured value _I 11 _{~I 1N} plurality of first current measuring section 51 to 5N, the measured value of the calculated sum value and the second current measuring unit 6 I the difference between the ₂ Request (absolute value) I _dif. Further, the failure detection unit 21 determines whether the obtained difference I _dif is _equal to or _larger than a predetermined determination threshold I _th (S2). Here, the determination threshold I _th may have an arbitrary size, but is set to, for example, a value smaller than the size of the measurement value I ₂ of the second current measurement unit 6. As described above, the second current measurement unit 6 measures the current of the electric path on the DC power supply 8 side of the branch point P1, and the plurality of first current measurement units 51 to 5N are branched from the branch point P1. The currents flowing through the plurality of power conversion circuits 11 to 1N are respectively measured. Therefore, when no failure occurs in any of the plurality of first current measurement units 51 to 5N and the second current measurement unit 6, the measurement values I _{11 to} I _1N of the plurality of first current measurement units 51 to 5N are obtained. The total value and the measurement value I _{2 of} the second current measurement unit 6 become substantially equal, and the difference I _dif becomes substantially zero. Based on this, the failure detection unit 21 selects one of the plurality of first current measurement units 51 to 5N and the second current measurement unit 6 when the difference I _dif is equal to or greater than the determination threshold I _th (S2: Yes). It is detected that a failure has occurred in the sensor (the measurement unit is in a failure state) (S3).

If the measurement unit is in a failure state, the failure detection unit 21 specifies which one of the plurality of first current measurement units 51 to 5N and the second current measurement unit 6 has a failure. Specifically, the failure detection unit 21 determines, for each of the plurality of power conversion circuits 1 n (n is an arbitrary integer of 1 to N), the measurement value I _{1 n} of the corresponding first current measurement unit 5 _n and the target Find the difference (absolute value) D _n with the value. Further, the failure detection unit 21 determines, for each of the plurality of power conversion circuits 1 _n , whether or not the calculated difference D _n is _{equal to} or greater than a predetermined first threshold Th _n . If there is a power conversion circuit 1 that satisfies the condition that the difference D _n is _{equal to} or more than the first threshold Th _n , the failure detection unit 21 breaks the first current measurement unit 5 corresponding to the power conversion circuit 1 that satisfies the condition. It detects that it is a fault measurement part which has occurred. The first threshold Th _n may be common to the plurality of power conversion circuits 1 n or may be different from each other.

More specifically, in the failure state of the measurement unit, the failure detection unit 21 sequentially determines whether or not the corresponding first current measurement unit 5n is a failure measurement unit for each of the plurality of power conversion circuits 1n. judge. The failure detection unit 21 first determines (S4) the first (i = 1) power conversion circuit 11 in which the determination order i (i is an integer of 1 to N) is the difference D ₁ obtained is the first threshold Th ₁ It is judged whether it is above (S5). If the difference _{D 1} is first smaller than the threshold Th ₁ (S5: No), the failure detection unit 21, a first current measuring unit 51 corresponding to the first power conversion circuit 11, a fault has not occurred correctly measured It is determined that it is a copy (S6). On the other hand, the difference _{D 1} is the first threshold value Th ₁ or more when (S5: Yes), the failure detection unit 21, a first current measuring unit 51 corresponding to the first power conversion circuit 11, a fault has occurred It is determined that it is a failure measurement unit (S7). The failure detection unit 21 stores in the storage unit 22 of the processing device 2 that the first current measurement unit 51 is a failure measurement unit (S8). Further, the failure detection unit 21 increases the number of failures FS (initial value is 0) indicating the number of failure measurement units by 1 (S9).

  After either step S6 or step S9, the failure detection unit 21 increases the determination order i by 1 (S10), and determines whether the determination order i exceeds the number N of the first current measurement units 5 or not. It determines (S11). If the determination order i does not exceed the number N of the first current measurement units 5 (S11: No), the failure detection unit 21 returns to step S5, and performs the operations of steps S5 to S9 for the next power conversion circuit 1i. . On the other hand, if the determination order i exceeds the number N of the first current measurement units 5 in step S11 (S11: Yes), the failure detection unit 21 determines the first current measurement units 5n for all the power conversion circuits 1n. It is determined that the determination as to whether or not the part is a failure measurement part is completed.

  Subsequently, the failure detection unit 21 determines whether the number of failures FS is larger than the initial value (S12). If the number of failures FS is larger than the initial value (S12: Yes), the failure detection unit 21 determines that a failure has occurred in any one of the plurality of first current measurement units 51 to 5N (S13). Further, the failure detection unit 21 reads out from the storage unit 22 which first current measurement unit 5 is the failure measurement unit, and notifies the control unit 20 and the notification device 230 of the failure measurement unit (S14 ), End the operation. On the other hand, when the number of failures FS remains the initial value (S12: No), the failure detection unit 21 determines that the second current measurement unit 6 has a failure (S15), and the control unit 20 and the notification The device 230 is notified that a failure has occurred in the second current measuring unit 6 (S14), and the operation is ended.

Returning to step S2, when the difference I _dif is less than the determination threshold I _th (S2: No), the failure detection unit 21 detects a failure in the plurality of first current measurement units 51 to 5N and the second current measurement unit 6 Is not generated (the measurement unit is in a normal state) (S21). In the normal state of the measurement unit, the failure detection unit 21 determines whether or not a failure occurs in the plurality of power conversion circuits 1 n.

When the measurement unit is in the normal state, the failure detection unit 21 determines, for each of the plurality of power conversion circuits 1n, the difference (absolute value) D _n between the measurement value I _{1 n} of the corresponding first current measurement unit 5 _n and the target value. Ask. Further, the failure detection unit 21 determines, for each of the plurality of power conversion circuits 1 _n , whether or not the calculated difference D _n is _{equal to} or more than a predetermined second threshold value Tx _n . If there is a power conversion circuit 1 that satisfies the condition that the difference D _n is the second threshold value Tx _n or more, the failure detection unit 21 converts the power conversion circuit 1 that satisfies the condition into a failed power conversion in which a failure occurs. It detects that it is a circuit. Note that the second threshold Tx _n may be common to the plurality of power conversion circuits 1 n or may be different from each other. Further, in each of the plurality of power conversion circuits 1 _n , the second threshold Tx _n may be the same as or different from the first threshold Th _n .

More specifically, when the measurement unit is in the normal state, the failure detection unit 21 sequentially detects whether or not each of the plurality of power conversion circuits 1 n is a failed power conversion circuit. Failure detection unit 21 first, for each of the plurality of power conversion circuit 1n, the difference (absolute value) between the measured value I _1n and the target value of the corresponding first current measuring unit 5n Request D _n. Then, the failure detection unit 21, determines the order j (i is 1 to N integer) (S22) for the power conversion circuit 11 of the first (j = 1), 2 is the difference _{D 1} obtained first threshold value Tx ₁ It is judged whether it is above (S23). If the difference _{D 1} is smaller than the second threshold value Tx ₁ (S23: No), the failure detection unit 21, a first power conversion circuit 11, detects that the failure is a normal power conversion circuit not occurred (S24 ). On the other hand, when the difference _{D 1} is the second threshold value Tx ₁ or more (S23: Yes), determines that the failure detection unit 21, the first power converter circuit 11, which is an object to be failed power conversion circuit failure has occurred (S25). The failure detection unit 21 stores in the storage unit 22 of the processing device 2 that the power conversion circuit 11 is a power failure conversion circuit (S26). Further, the failure detection unit 21 increases the number of failures FC (initial value is 0) indicating the number of power conversion circuits to be increased by 1 (S27).

  After either step S24 or step S27, the failure detection unit 21 increases the determination order j by 1 (S28), and determines whether the determination order j exceeds the number N of power conversion circuits 1 or not. (S29). If the determination order j does not exceed the number N of power conversion circuits 1 (S29: No), the failure detection unit 21 returns to step S23, and performs the operations of steps S23 to S28 for the next power conversion circuit 1j. On the other hand, if the determination order j exceeds the number N of the power conversion circuits 1 in step S29 (S29: Yes), the failure detection unit 21 determines whether all the power conversion circuits 1n are failure power conversion circuits. It is determined that the determination of the

  Subsequently, the failure detection unit 21 determines whether the number of failures FC is larger than the initial value (S30). If the failure number FC is larger than the initial value (S30: Yes), the failure detection unit 21 determines that a failure has occurred in any of the plurality of power conversion circuits 11 to 1N (S31). Further, the failure detection unit 21 reads from the storage unit 22 which power conversion circuit is the power conversion circuit to be damaged, and notifies the control unit 20 and the notification device 230 of the power conversion circuit to be failed (S14). End the operation. On the other hand, when the number of failures FC remains the initial value (S30: No), the failure detection unit 21 is any of the plurality of first current measurement units 5, the second current measurement unit 6, and the plurality of power conversion circuits 1. Also, it is determined that no failure has occurred (S32), and the operation is ended.

  The failure detection unit 21 performs the above-described operation at an arbitrary timing (for example, a fixed cycle), and determines whether or not a failure occurs and identifies a failure point.

(1.4) Operation at the Time of Failure Detection Next, an operation of the control unit 20 when receiving a notification of a failure point from the failure detection unit 21 will be described using an example shown in FIG. The control unit 20 controls (changes) the operation of the plurality of power conversion circuits 1 in accordance with the notified failure point.

(1.4.1) At the time of failure of the first measurement unit First, the control unit 20 causes the failure detection unit 21 to cause a failure in any one of the plurality of first current measurement units 51 to 53 (a plurality of The case where the notification indicating that any one of the first current measurement units 51 to 53 is the failure measurement unit will be described.

  When the control unit 20 receives the notification from the failure detection unit 21, the control unit 20 determines the number of failure measurement units (the number of failures FS). The control unit 20 determines that there is a possibility that difficulty may arise in operating the plurality of power conversion circuits 1 normally if the number of failures FS is 2 or more, and, for example, all the power conversion circuits 11 to Stop the operation of 13.

  On the other hand, if the number of failures FS is 1, the control unit 20 determines that the plurality of power conversion circuits 11 to 13 can operate normally, and continues the operation of the plurality of power conversion circuits 11 to 13 Let At this time, a method of causing the control unit 20 to operate the plurality of power conversion circuits 11 to 13 will be described below. In the following, the case where a failure occurs in the first current measurement unit 51 among the plurality of first current measurement units 51 to 53 will be described, but the failure in the first current measurement unit 52 or the first current measurement unit 53 is described. Is the same as when.

As described above, the control unit 20 acquires the measurement values I _{11 to} I ₁₃ from the plurality of first current measurement units 51 to 53, and acquires the measurement value I ₂ from the second current measurement unit 6. Here, the control unit 20, when the first current measuring unit 51 has received from the failure detection unit 21 a notice indicating that the failure measurement unit, the measurement value obtained from the first current measuring unit 51 I ₁₁ is the correct value (It does not reflect the current actually flowing through the power conversion circuit 11). Then, the control unit 20 uses the measurement value I ₂ acquired from the second current measurement unit 6 and the measurement values I ₁₂ and I ₁₃ acquired from the remaining first current measurement units 52 and 53 (normal measurement unit). The first current measurement unit 51 calculates the correct value (computed value) of the current to be measured. Specifically, the control unit 20 subtracts the total value of the measurement values I ₁₂ and I ₁₃ acquired from the first current measurement units 52 and 53 from the measurement value I ₂ acquired from the second current measurement unit 6 Let (I ₂ − (I ₁₂ + I ₁₃ )) be a calculated value. The control unit 20 controls the operation of the power conversion circuit 11 such that the calculated value obtained approaches the target value for the power conversion circuit 11 corresponding to the failure measurement unit (first current measurement unit 51). . In the power conversion circuits 12 and 13 corresponding to the first current measurement units 52 and 53 which are normal measurement units, the measurement values I ₁₂ and I ₁₃ of the corresponding first current measurement units 52 and 53 approach the target value. Thus, the control unit 20 may control the operations of the power conversion circuits 12 and 13 respectively.

As described above, in the present embodiment, instead of the measured value I ₁₁ of the failure measurement unit, the measurement by the first current measuring unit 52, 53 is a measured value I ₂ and the normal measurement unit by the second current measuring section 6 The calculated value is calculated from the values I ₁₂ and I ₁₃ . Then, in the present embodiment, the operation of the power conversion circuit 11 corresponding to the failure measurement unit is continued using the calculated operation value. As a result, even when a failure occurs in any of the first current measurement units 5, it is possible to continue the operation of all the power conversion circuits 11 to 13. That is, it is possible to cause the power conversion system 100 to output the same level of power as when there is no failure in the plurality of first current measurement units 51 to 53.

Further, in the present embodiment, when the number of failure measurement units (number of failures FS) is two or more, the operation of all the power conversion circuits 11 to 13 is stopped. Here, if the number of the failure measurement unit 2 or more, than from only the measured value by the measurement value I ₂ and the remainder of the first current measuring unit 5 of the second current measuring section 6 (normal measurement unit), the fault It is not possible to accurately obtain each of the current values to be measured by the measurement unit. That is, only the sum value of the currents flowing through the two or more power conversion circuits corresponding to the two or more fault measurement units can be calculated. Therefore, in order to obtain the current flowing through the power conversion circuit corresponding to two or more fault measurement units, it is necessary to assume, for example, that the currents flowing through the power conversion circuit corresponding to the fault measurement unit are equal to each other. . For this reason, there is a possibility that a problem may occur such as the operation of the power conversion circuit corresponding to the failure measurement unit becoming unstable. On the other hand, as in the present embodiment, when the number of failure measurement units (number of failures FS) is two or more, such operations can be performed by stopping the operation of all the power conversion circuits 11 to 13. It becomes possible to suppress the occurrence of a defect.

  Of course, if the value to be measured by the failure measurement unit can be correctly estimated from the measurement value of the second current measurement unit 6 and the measurement value of the normal measurement unit, even if there are two or more failure measurement units. The operation of the plurality of power conversion circuits 1 may be continued. For example, the plurality of power conversion circuits 11 to 13 all have the same configuration, and the same control signal is transmitted to the plurality of power conversion circuits 11 to 13 to perform the same operation on the plurality of power conversion circuits 11 to 13 In the case of the configuration, the currents flowing through the plurality of power conversion circuits 11 to 13 become substantially equal. In this case, the total value of the measurement values of the normal measurement unit is subtracted from the measurement value of the second current measurement unit 6, and the obtained value is equally divided to obtain the current flowing through the power conversion circuit corresponding to the failure measurement unit. It is possible to estimate the value.

(1.4.2) When the Second Measurement Unit Fails Next, when the control unit 20 receives a notification from the failure detection unit 21 that the second current measurement unit 6 has a failure, explain.

As described above, the control unit 20 acquires the measurement values I _{11 to} I ₁₃ from the plurality of first current measurement units 51 to 53, and acquires the measurement value I ₂ from the second current measurement unit 6. Here, when the control unit 20 receives from the failure detection unit 21 a notification that the second current measurement unit 6 is a failure measurement unit, the measurement value I ₂ acquired from the second current measurement unit 6 is a correct value. (It does not reflect the current which actually flows through the pair of power supply side terminals 31 and 32). The control unit 20 then uses the measurement values I _{11 to} I ₁₃ acquired from the plurality of first current measurement units 51 to 53 to calculate the correct value (calculation value) of the current to be measured by the second current measurement unit 6. Calculate Specifically, the control unit 20 obtains a total value of the measurement values I _{11 to} I ₁₃ acquired from the plurality of first current measurement units 51 to 53 as a calculation value. The control unit 20 transmits the calculated operation value to, for example, the DC power supply 8, and the DC power supply 8 continues the operation using the operation value received from the control unit 20.

On the other hand, the failure detection unit 21 continues the operation of the plurality of power conversion circuits 11 to ₁₃ using the measurement values I _{11 to} I ₁₃ acquired from the plurality of first current measurement units 51 to 53.

As described above, in the present embodiment, instead of the measured value _{I 2} of the second current measuring unit 6, from the measured value _I 11 _{~I 13} by a plurality of first current measuring section 51 to 53, seeking operation value There is. Then, for example, as such transmits the calculated value to the DC power source 8 which operates using the measurement value I ₂ of the second current measuring section 6, by using the calculated value obtained, a plurality of power conversion circuits 11 to 13 The operation of is continued. As a result, even when a failure occurs in the second current measurement unit 6, the operation of the power conversion circuits 11 to 13 can be continued. That is, it is possible to cause the power conversion system 100 to output the same amount of power as when there is no failure in the second current measurement unit 6.

(1.4.3) At the time of failure of the power conversion circuit Finally, the control unit 20 causes the failure detection unit 21 to cause a failure in any of the plurality of power conversion circuits 11 to 13 (a plurality of power conversions) A case will be described in which one of the circuits 11 to 13 is notified that the received power is a faulty power conversion circuit. Although the case where a failure occurs in the power conversion circuit 11 among the plurality of power conversion circuits 11 to 13 will be described below, the same applies to the case where a failure occurs in the power conversion circuit 12 or the power conversion circuit 13.

When receiving notification from power failure detection unit 21 that power conversion circuit 11 is a power failure conversion circuit, control unit 20 stops the operation of power conversion circuit 11. On the other hand, the control unit 20 continues the operation of the power conversion circuits 12 and ₁₃ using the measurement values I ₁₂ and I ₁₃ of the first current measurement units 51 and 52. As described above, in the present embodiment, when it is detected that a failure occurs in any of the plurality of power conversion circuits 11 to 13, the operation of the power conversion circuit 11 detected as having the failure is stopped, and the remaining The operation of the power conversion circuits 12 and 13 is continued. As a result, although the maximum value of the power that can be output from the power conversion system 100 decreases by the amount of stopping the operation of the power conversion circuit 11, it is possible to continue the output of power from the power conversion system 100.

  In the case where the operation of the power conversion circuit 11 is stopped when the plurality of power conversion circuits 11 to 13 are operating in a state where the output power is smaller than the rated power, the control unit 20 The output powers of the remaining power conversion circuits 12 and 13 may be increased. For example, it is assumed that the rated power of each of the plurality of power conversion circuits 11 to 13 is 1000 W, and each is operating at an output power of 700 W (that is, the total output power is 2100 W). In this state, when the power conversion circuit 11 is stopped, the control unit 20 controls the control signal to increase the output power of the power conversion circuits 12 and 13 to 1000 W (the total output power is 2000 W). Thereby, the reduction of the power output from power conversion system 100 can be suppressed.

(2) Embodiment 2
The power conversion system 200 of Embodiment 2 will be described with reference to FIG. FIG. 5 is a system configuration diagram of the power conversion system 200 of the present embodiment.

  The power conversion system 200 according to the present embodiment is characterized in that the plurality of power conversion circuits 11 to 13 are connected in a so-called series between the pair of first terminals and the pair of second terminals. It differs from the power conversion system 100. Further, in the power conversion system 200 of the present embodiment, a plurality of first measurement units 251 to 253 and a second measurement unit 26 are provided instead of the plurality of first measurement units 51 to 53 and the second measurement unit 6. And the power conversion system 100 of the first embodiment. Each of the plurality of first measurement units 251 to 253 respectively measure the voltage between the first capacitors (here, the capacitor C1) (see FIG. 2) of the corresponding power conversion circuits 11 to 13. The second measurement unit 26 measures the voltage between the pair of first terminals (here, the pair of power supply side terminals 31 and 32). In the present embodiment, the same components as in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Moreover, below, the 1st measurement part 25 (1st measurement part 251-253) is called 1st voltage measurement part 25 (1st voltage measurement part 251-253), and 2nd measurement part 26 is 2nd voltage measurement part. It is called 26.

  In the power conversion system 200 of the present embodiment, the capacitors C1 respectively provided in the plurality of power conversion circuits 11 to 13 are electrically connected in series between the pair of power supply side terminals 31 and 32. Specifically, the high potential side power supply side terminal 31 is electrically connected to the high potential side input terminal T11 of the power conversion circuit 11, and the low potential side input terminal T12 of the power conversion circuit 11 is power conversion It is electrically connected to the input terminal T11 on the high potential side of the circuit 12. Further, the low potential side input terminal T12 of the power conversion circuit 12 is electrically connected to the high potential side input terminal T11 of the power conversion circuit 13, and the low potential side input terminal T12 of the power conversion circuit 13 is low. It is electrically connected to the power supply side terminal 32 on the potential side (see FIGS. 2 and 5). Further, capacitors C2 respectively provided in the plurality of power conversion circuits 11 to 13 are electrically connected in series between the pair of bus side terminals 41 and 42. Specifically, the high potential side bus side terminal 41 is electrically connected to the high potential side output terminal T21 of the power conversion circuit 11, and the low potential side output terminal T22 of the power conversion circuit 11 is power conversion The output terminal T21 on the high potential side of the circuit 12 is electrically connected. Further, the low potential side output terminal T22 of the power conversion circuit 12 is electrically connected to the high potential side output terminal T21 of the power conversion circuit 13, and the low potential side output terminal T22 of the power conversion circuit 13 is low. It is electrically connected to the potential-side bus side terminal 42 (see FIGS. 2 and 5).

  Each of the plurality of power conversion circuits 1 converts the voltage (input voltage V1) input via the pair of input terminals T11 and T12 into a desired voltage (output voltage V2), and outputs the pair of output terminals T21 and T22. Output from That is, in the power conversion system 200, DC voltages input to the pair of power supply side terminals 31 and 32 are divided by the capacitors C1 provided in the plurality of power conversion circuits 11 to 13, respectively. Each of the plurality of power conversion circuits 11 to 13 converts the voltage between the capacitors C1 into a desired voltage and outputs the voltage from the capacitor C2. The power conversion system 200 outputs the combined voltage of the capacitors C2 respectively provided in the plurality of power conversion circuits 11 to 13 from the pair of bus side terminals 41 and 42 to the intermediate bus 9.

  Each of the plurality of first voltage measurement units 25 is electrically connected across the first capacitor (here, the capacitor C1) of the corresponding power conversion circuit 1. Each of the plurality of first voltage measurement units 25 has a function of measuring the voltage between the first capacitors of the corresponding power conversion circuit 1.

  The second voltage measurement unit 26 is electrically connected between the pair of first terminals (here, the pair of power supply side terminals 31 and 32). The second voltage measurement unit 26 has a function of measuring the voltage between the pair of first terminals.

  Each of the plurality of first voltage measuring units 25 and the second voltage measuring unit 26 is configured using, for example, a pair of voltage dividing resistors, and outputs a signal corresponding to the measured value (voltage value) to the processing device 2 Do.

  The processing device 2 acquires the measurement results (measurement values) of the plurality of first voltage measurement units 25 and the second voltage measurement unit 26, and refers to the acquired measurement values so that the output voltage V2 approaches the target voltage Control the switching elements Q1 of the plurality of power conversion circuits 1; Specifically, in the control unit 20 of the processing device 2, the output voltage V 2 approaches the target voltage, and for each of the plurality of power conversion circuits 1, the measurement value of the corresponding first voltage measurement unit 25 becomes the target value. The duty of the control signal given to the plurality of power conversion circuits 1 is adjusted to be close.

  The failure detection unit 21 obtains a difference between the measurement value of the second voltage measurement unit 26 and the measurement values of the plurality of first voltage measurement units 251 to 253. When the calculated difference is equal to or greater than the determination threshold, the failure detection unit 21 has a failure in any one of the plurality of first voltage measurement units 251 to 253 and the second current measurement unit 26 (measurement unit failure Detect that).

  The other operations of the control unit 20 and the failure detection unit 21 are the same as in the first embodiment, and thus detailed description will be omitted.

  Even in the power conversion system 200 of the present embodiment, it is detected which of the plurality of power conversion circuits 1, the plurality of first voltage measuring units 25 and the second voltage measuring unit 26 has a failure. It becomes possible. Moreover, it becomes possible to perform control according to a failure part.

(3) Modification Below, the power conversion system which concerns on the modification of the said embodiment is listed. In addition, each composition of a modification explained below is applicable suitably combining with each composition explained by the above-mentioned embodiment.

  The functions similar to those of the processing apparatus 2 (the control unit 20 and / or the failure detection unit 21) in the first and second embodiments are embodied by a failure detection method, a computer program, or a non-temporary recording medium recording the program. May be

  The failure detection method according to an aspect is used in a power conversion system 100 including a plurality of power conversion circuits 1 and a control unit 20 that controls the operation of the plurality of power conversion circuits 1. The failure detection method is based on the measurement values of the plurality of first measurement units 5 and the measurement values of the plurality of second measurement units 6 to obtain a plurality of first measurement units 5, a second measurement unit 6, and a plurality of power conversion circuits. It is detected which of 1 has a failure. Here, the plurality of power conversion circuits 1 are electrically connected in parallel between the pair of first terminals (a pair of power supply side terminals 31 and 32) and the pair of second terminals (a pair of bus side terminals 41 and 42). It is connected and converts the input voltage into a desired voltage. Further, the plurality of first measurement units 5 are provided to correspond to the plurality of power conversion circuits 1 in a one-to-one manner, and respectively measure the current flowing through the corresponding power conversion circuits 1. The second measuring unit 6 measures the current flowing through the pair of first terminals.

  A program according to an aspect is a program for causing a computer system to execute a failure detection process. The program is used in a power conversion system 100 including a plurality of power conversion circuits 1 and a control unit 20 that controls the operation of the plurality of power conversion circuits 1. The failure detection process is performed based on the measurement values of the plurality of first measurement units 5 and the measurement values of the second measurement unit 6, in the plurality of first measurement units 5, second measurement units 6, and the plurality of power conversion circuits 1. This is a process of detecting which one has a failure. Here, the plurality of power conversion circuits 1 are electrically connected in parallel between the pair of first terminals (a pair of power supply side terminals 31 and 32) and the pair of second terminals (a pair of bus side terminals 41 and 42). It is connected and converts the input voltage into a desired voltage. Further, the plurality of first measurement units 5 are provided to correspond to the plurality of power conversion circuits 1 in a one-to-one manner, and respectively measure the current flowing through the corresponding power conversion circuits 1. The second measuring unit 6 measures the current flowing through the pair of first terminals.

  The failure detection method according to an aspect is used in a power conversion system 200 including a plurality of power conversion circuits 1 and a control unit 20 that controls the operations of the plurality of power conversion circuits 1. The failure detection method is based on the measurement values of the plurality of first measurement units 25 and the measurement values of the second measurement unit 26, in the plurality of first measurement units 25, the second measurement units 26, and the plurality of power conversion circuits 1. It detects which failure has occurred. Here, in the plurality of power conversion circuits 1, the first capacitors (capacitors C1) respectively provided are electrically connected in series between the pair of first terminals (the pair of power supply side terminals 31, 32). In the plurality of power conversion circuits 1, the second capacitors (capacitors C2) respectively provided are electrically connected in series between the pair of second terminals (the pair of bus side terminals 41 and 42). The plurality of power conversion circuits 1 convert a voltage input through one of the first and second capacitors into a desired voltage, and output the voltage from the other of the first and second capacitors. The plurality of first measurement units 25 are provided to correspond to the plurality of power conversion circuits 1 in a one-to-one manner, and respectively measure the voltage between the first capacitors of the corresponding power conversion circuits 1. The second measurement unit 26 measures the voltage between the pair of first terminals.

  A program according to an aspect is a program for causing a computer system to execute a failure detection process. The program is used in a power conversion system 200 including a plurality of power conversion circuits 1 and a control unit 20 that controls the operation of the plurality of power conversion circuits 1. The failure detection process is performed based on the measurement values of the plurality of first measurement units 25 and the measurement values of the second measurement unit 26, in the plurality of first measurement units 25, second measurement units 26, and the plurality of power conversion circuits 1. This is a process of detecting which one has a failure. Here, in the plurality of power conversion circuits 1, the first capacitors (capacitors C1) respectively provided are electrically connected in series between the pair of first terminals (the pair of power supply side terminals 31, 32). In the plurality of power conversion circuits 1, the second capacitors (capacitors C2) respectively provided are electrically connected in series between the pair of second terminals (the pair of bus side terminals 41 and 42). The plurality of power conversion circuits 1 convert a voltage input through one of the first and second capacitors into a desired voltage, and output the voltage from the other of the first and second capacitors. The plurality of first measurement units 25 are provided to correspond to the plurality of power conversion circuits 1 in a one-to-one manner, and respectively measure the voltage between the first capacitors of the corresponding power conversion circuits 1. The second measurement unit 26 measures the voltage between the pair of first terminals.

  Here, the control unit 20, the control method and / or the failure detection unit 21, and the execution subject of the failure detection method include a computer system. The computer system mainly includes a processor and memory as hardware. The processor executes the program stored in the memory of the computer system, whereby the function as the execution subject of the control unit 20, the control method and / or the failure detection unit 21 or the failure detection method is realized. The program may be pre-recorded in the memory of the computer system. Also, the program may be provided through a telecommunication line, or may be provided by being recorded on a non-transitory recording medium such as a computer system readable memory card, an optical disk, a hard disk drive and the like. A processor of a computer system is configured of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The plurality of electronic circuits may be integrated into one chip or may be distributed to a plurality of chips. The plurality of chips may be integrated into one device or may be distributed to a plurality of devices.

  Moreover, although the processing apparatus 2 of Embodiment 1, 2 is implement | achieved by one apparatus, it is not limited to this structure. At least one of the functions of control unit 20, failure detection unit 21, and notification unit 23 of power conversion systems 100 and 200 may be distributed to two or more systems. Further, the functions of the control unit 20, the failure detection unit 21, and the notification unit 23 may be distributed to a plurality of devices. For example, certain functions of power conversion system 100 may be distributed to a plurality of systems. Also, at least part of the functions of the power conversion system 100 may be realized by, for example, a cloud (cloud computing).

  Control unit 20 stops the operation of power conversion circuit 1 corresponding to the failure measurement unit when it is detected that any one of the plurality of first measurement units 51 to 53 (251 to 253) is the failure measurement unit. The operation of the remaining power conversion circuit 1 may be continued. For example, when the failure detection unit 21 detects that the first current measurement unit 51 is a failure measurement unit, the control unit 20 stops the operation of the power conversion circuit 11 corresponding to the first current measurement unit 51, The operation of the remaining power conversion circuits 12 and 13 may be continued. In this case, although the maximum value of the power that can be output from the power conversion system 100 decreases by stopping the operation of the power conversion circuit 1 corresponding to the failure measurement unit, the output of power from the power conversion system 100 is continued. It is possible to

  The control unit 20 detects that a failure has occurred in any of the plurality of power conversion circuits 1, the plurality of first measuring units 51 to 53 (251 to 253), and the second measuring unit 6 (26). Then, the operation of all the power conversion circuits 11 to 13 may be stopped. In this case, all the operations of the system including the devices (the first measuring unit 5 (25), the second measuring unit 6 (26), and the power conversion circuit 1) which may have a failure are stopped. Therefore, it is possible to improve safety.

  The circuit configuration of the power conversion circuit 1 is not limited to the configuration of FIG. For example, as shown in FIG. 6, the power conversion circuit 1 may be configured by a bidirectional chopper circuit. The power conversion circuit 1 includes a switching element Q2 in place of the diode D1 in the circuit of FIG. The switching element Q2 is formed of an enhancement type n-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Specifically, the power conversion circuit 1 includes two capacitors C1 and C2, an inductor L1, and two switching elements Q1 and Q2. The capacitor C1 is electrically connected between the pair of first connection terminals T11 and T12. The capacitor C2 is electrically connected between the pair of second connection terminals T21 and T22. The first end of the inductor L1 is electrically connected to the first connection terminal T11 on the high potential side, and the second end is electrically connected to the drain of the switching element Q1 and the source of the switching element Q2. The source of the switching element Q1 is electrically connected to the low potential first connection terminal T12 and the second connection terminal T22. In the power conversion circuit 1, the control unit 20 controls the switching elements Q1 and Q2 to convert a DC voltage input between the pair of first connection terminals T11 and T12 to convert the pair of second connection terminals T21, It has a function to output during T22. The power conversion circuit 1 further has a function of converting a DC voltage input between the pair of second connection terminals T21 and T22 and outputting the voltage between the pair of first connection terminals T11 and T12. Therefore, in the power conversion system 100 including the power conversion circuit 1, it is possible to perform charging and discharging of the storage battery as the DC power supply 8.

  The power conversion circuit 1 is not limited to a so-called DC-DC converter that converts a DC voltage into a DC voltage. The power conversion circuit 1 may be a so-called DC-AC inverter that converts a DC voltage into an AC voltage. In this case, for example, an alternating current load 92 such as a power system is electrically connected to the pair of bus side terminals 41 and 42.

  The pair of first terminals may be the pair of bus side terminals 41 and 42, and the pair of second terminals may be the pair of power supply side terminals 31 and 32. In one specific example, in the power conversion circuit 100 of the first embodiment, each of the plurality of first current measurement units 5 includes the pair of output terminals T21 and T22 of the corresponding power conversion circuit 1 and the pair of bus side terminals 41 and 42. And the second current measurement unit 6 is provided to the pair of bus side terminals 41 and 42. In this case, each of the plurality of first current measurement units 5 measures the current flowing through the pair of output terminals T21, T22 of the corresponding power conversion circuit 1, and the second measurement unit 6 measures the pair of bus side terminals 41, Measure the current flowing through 42. In another specific example, in the power conversion device 200 of the second embodiment, each of the plurality of first voltage measurement units 25 is provided between the pair of output terminals T21 and T22 of the corresponding power conversion circuit 1, and the second The voltage measurement unit 26 is provided between the pair of bus side terminals 41 and 42. In this case, each of the plurality of first voltage measurement units 25 measures the voltage between the pair of output terminals T21 and T22 of the corresponding power conversion circuit 1, and the second voltage measurement unit 26 measures the pair of bus side terminals 41. , 42 and measure the voltage.

  Furthermore, each of the plurality of first current measurement units 5 measures the current flowing through the pair of input terminals T11 and T12 of the corresponding power conversion circuit 1, and the second current measurement unit 6 measures the pair of bus side terminals 41, The current flowing through 42 may be measured. In this case, the failure detection unit 21 determines the pair of power supply side terminals 31 from the product of the measurement value measured by the second current measurement unit 6 and the ratio (V2 / V1) of the input voltage V1 to the output voltage V2. Convert the value of the current flowing through 32. Then, from the difference between the converted value and the total value of the measurement values of the plurality of first current measurement units 5, the failure detection unit 21 determines that the failure in the first current measurement unit 5 or the second current measurement unit 6 has occurred. Detect the occurrence.

  Similarly, each of the plurality of first voltage measurement units 25 measures the voltage between the pair of input terminals T11 and T12 of the corresponding power conversion circuit 1, and the second voltage measurement unit 6 measures the pair of bus side terminals 41. , 42 may be measured. Then, the failure detection unit 21 may convert the voltage between the pair of power supply side terminals 31 and 32. Conversely, each of the plurality of first current measurement units 5 measures the current flowing through the pair of output terminals T21, T22 of the corresponding power conversion circuit 1, and the second current measurement unit 6 measures the pair of power supply side terminals 31. , 32 may be measured. Then, the failure detection unit 21 may convert the current flowing through the pair of power supply side terminals 41 and 42. Further, each of the plurality of first voltage measurement units 25 measures the voltage between the pair of output terminals T21 and T22 of the corresponding power conversion circuit 1, and the second voltage measurement unit 6 measures the pair of power supply side terminals 31, The voltage between 32 may be measured. Then, the failure detection unit 21 may convert the voltage between the pair of bus side terminals 41 and 42.

  The number of power conversion circuits 1 and the corresponding first measuring units 5 (25) is not limited to three. The number of power conversion circuits 1 and the corresponding first measuring units 5 may be two or four or more.

  The plurality of power conversion circuits 1, the plurality of first measurement units 5, and the processing device 2 may be housed in one case. For example, a plurality of sub-housings accommodating one power conversion circuit 1 and the corresponding first measurement unit 5 may be accommodated in one case.

  The second measurement unit 6 may be housed together in a housing in which the power conversion circuit 1 is housed, may be housed in another housing, or in a housing for housing the DC power supply 8. It may be accommodated.

  The failure of the first measurement unit 5 (25) and the second measurement unit 6 (26) is not limited to the state where the measurement value is not output from the measurement unit. For example, the failure of the first measurement unit 5 (25) and the second measurement unit 6 (26) includes a state in which the measurement value is output from the measurement unit but the measurement value is not appropriate.

  In steps S4 to S11, the failure detection unit 21 determines the failure of the plurality of first measurement units 5 in order, but may perform the determination at the same time. Similarly, in steps S22 to S29, the failure detection unit 21 sequentially determines the failure of the plurality of power conversion circuits 1, but may simultaneously perform the determination.

  The control unit 20 controls the operation of each power conversion circuit 1 such that the measurement value of the first measurement unit 5 (25) approaches the target value for each of the plurality of power conversion circuits 1. I can not. The control unit 20 causes the measurement values of the plurality of first measurement units 5 (25) to approach each other, and the total value of the measurement values of the plurality of first measurement units 5 approaches the target value. The operation may be controlled. In this case, the failure detection unit 21 determines whether a plurality of first measurement units 5 (25) or a plurality of first measurement units 5 (25) are based on whether the difference between the measurement values of the plurality of first measurement units 5 (25) exceeds a predetermined threshold. It may be determined in which of the power conversion circuits 1 a failure occurs.

  The load 92 is not limited to a device or a power system that operates by receiving an AC voltage, or may be a device that operates by receiving a DC voltage. In this case, the inverter circuit 91 is unnecessary.

  The notification device 230 may be integral with the processing device 2.

  In the first embodiment, the control unit 20 controls the output voltage V2 to approach the target voltage, and controls the measurement value of the corresponding first current measurement unit 5 to approach the target value for each of the plurality of power conversion circuits 1. But it is not limited to this. For example, the control unit 20 causes the current (output current) flowing through the pair of bus side terminals 41 and 42 to approach the target current, and the measured value of the corresponding first current measurement unit 5 for each of the plurality of power conversion circuits 1 May be controlled to approach the target value. Similarly, in the second embodiment, the control unit 20 causes the output voltage V2 to approach the target voltage, and for each of the plurality of power conversion circuits 1, the measurement value of the corresponding first voltage measurement unit 25 approaches the target value. Although it controls, it is not restricted to this. For example, the control unit 20 causes the current (output current) flowing through the pair of bus terminals 41 and 42 to approach the target current, and the measured value of the first voltage measurement unit 25 corresponding to each of the plurality of power conversion circuits 1. May be controlled to approach the target value.

(4) Advantages As described above, the power conversion system (100) according to the first aspect includes the plurality of power conversion circuits (1), the control unit (20), and the failure detection unit (21). Prepare. The plurality of power conversion circuits (1) are electrically connected in parallel between the pair of first terminals (power supply side terminals 31, 32) and the pair of second terminals (bus side terminals 41, 42), and are input. Convert the voltage into the desired voltage. The control unit (20) controls the operation of the plurality of power conversion circuits (1). The failure detection unit (21) measures a plurality of first measurements from the measurement values of the plurality of first measurement units (the first current measurement unit 5) and the measurement values of the second measurement unit (the second current measurement unit 6). It is detected which of the unit (5), the second measuring unit (6), and the plurality of power conversion circuits (1) has a failure. The plurality of first measurement units (5) are provided to correspond to the plurality of power conversion circuits (1) in a one-to-one manner, and measure the currents flowing through the corresponding power conversion circuits (1). The second measurement unit (6) measures the current flowing through the pair of first terminals.

  According to the first aspect, the failure detection unit (21) causes a failure in any of the plurality of first measurement units (5), the second measurement units (6), and the plurality of power conversion circuits (1). Are identified. Therefore, the control unit (20) can cause the plurality of power conversion circuits (1) to perform an operation according to the failure location specified by the failure detection unit (21).

  A power conversion system (200) according to a second aspect includes a plurality of power conversion circuits (1), a control unit (20), and a failure detection unit (21). In the plurality of power conversion circuits (1), the first capacitors (capacitors C1) included in each are electrically connected in series between the pair of first terminals (power supply side terminals 31, 32). In the plurality of power conversion circuits (1), the second capacitors (capacitors C2) respectively provided are electrically connected in series between the pair of second terminals (bus-side terminals 41 and 42). The plurality of power conversion circuits (1) convert a voltage input through one of the first capacitor and the second capacitor into a desired voltage, and output the voltage from the other of the first capacitor and the second capacitor. The control unit (20) controls the operation of the plurality of power conversion circuits (1). The failure detection unit (21) generates a plurality of first measurements from the measurement values of the plurality of first measurement units (the first voltage measurement unit 25) and the measurement values of the second measurement unit (the second voltage measurement unit 26). It is detected which of the measurement unit (25), the second measurement unit (26), and the plurality of power conversion circuits (1) has a failure. The plurality of first measurement units 25 are provided to correspond to the plurality of power conversion circuits (1) in a one-to-one manner, and measure the voltage between the first capacitors (C1) of the corresponding power conversion circuits (1). . The second measurement unit (26) measures the voltage between the pair of first terminals.

  According to the second aspect, the failure detection unit (21) causes a failure in any of the plurality of first measurement units (5), the second measurement units (6), and the plurality of power conversion circuits (1). Are identified. Therefore, the control unit (20) can cause the plurality of power conversion circuits (1) to perform an operation according to the failure location specified by the failure detection unit (21).

  The power conversion system (100; 200) according to the third aspect is configured as follows in the first or second aspect. That is, in the failure detection unit (21), the difference between the total value of the measurement values of the plurality of first measurement units (5; 25) and the measurement value of the second measurement unit (6; 26) is equal to or greater than a predetermined determination threshold And detect that the measurement unit is in a failure state. The measurement unit failure state is a state in which a failure has occurred in any one of the plurality of first measurement units (5; 25) and the second measurement units (6; 26).

  According to the third aspect, it is possible to detect that a failure has occurred in any of the plurality of first measuring units (5; 25) and the second measuring units (6; 26). Thereby, the control unit (20) performs a plurality of operations corresponding to occurrence of a failure in any one of the plurality of first measuring units (5; 25) and the second measuring units (6; 26). It is possible to cause the power conversion circuit (1) to perform.

  In the power conversion system (100; 200) according to the fourth aspect, in the third aspect, the control unit (20) controls, for each of the plurality of power conversion circuits (1), a corresponding first measurement unit (5; Control is performed so that the measured value in 25) approaches the target value. The failure detection unit (21) has a condition that the measurement unit is in a failure state and any one of the plurality of first measurement units (5; 25) has a difference between the measurement value and the target value equal to or more than the threshold value. If satisfied, the first measurement unit (5; 25) that satisfies the condition is detected as a failure measurement unit in which a failure has occurred.

  According to the fourth aspect, it is possible to detect the occurrence of a failure in the first measurement unit (5; 25), and to specify the first measurement unit (5; 25) in which the failure occurs. It becomes possible. As a result, the control unit (20) can cause the plurality of power conversion circuits (1) to perform an operation according to the first measurement unit (5; 25) in which the failure has occurred.

  In the power conversion system (100; 200) according to the fifth aspect, in the fourth aspect, the control unit (20) is a power conversion circuit corresponding to the failure measurement unit among the plurality of power conversion circuits (1). The operation of (1) is stopped, and the operation of the remaining power conversion circuit (1) is continued.

  According to the fifth aspect, even when a failure occurs in any of the first measurement units (5; 25), it is possible to continue the output of power from the power conversion system (100; 200).

  In the power conversion system (100; 200) according to the sixth aspect, in the fourth or fifth aspect, the control unit (20) performs all of the plurality of powers when the number of fault measurement units is two or more. Stop the operation of the conversion circuit (1).

  According to the sixth aspect, since the operation of the system including the first measuring unit (5; 25) which may have a failure is all stopped, the safety can be improved.

  The power conversion system (100; 200) according to the seventh aspect operates as follows in the fourth aspect. That is, the control unit (20) substitutes the measurement value of the failure measurement unit and measures the measurement value by the second measurement unit (6; 26) and the measurement by the first measurement unit (5; 25) other than the failure measurement unit. The operation of the power conversion circuit (1) corresponding to the failure measurement unit is continued using the value calculated from the value.

  According to the seventh aspect, even when a failure occurs in any of the first measurement units (5; 25), it is possible to continue the operation of all the power conversion circuits (1). That is, from the power conversion system (100; 200), it is possible to cause the plurality of first measuring units (5) to output the same level of power as when there is no failure.

  The power conversion system (100; 200) according to the eighth aspect operates as follows in the fourth aspect. That is, when the failure detection unit (21) is in the measurement unit failure state and none of the plurality of first measurement units (5; 25) satisfy the above condition, the second measurement unit (6; 26) is detected as a failure measurement unit in which a failure has occurred.

  According to the eighth aspect, it is possible to detect that a failure has occurred in the second measurement unit (6; 26). Thus, the control unit (20) can cause the plurality of power conversion circuits (1) to perform an operation according to the occurrence of the failure in the second measurement unit (6; 26).

  The power conversion system (100; 200) according to the ninth aspect operates as follows in the eighth aspect. That is, the control unit (20) substitutes the measurement values of the second measurement unit (6; 26) with a plurality of values calculated using the measurement values of the plurality of first measurement units (5; 25). The operation of the power conversion circuit (1) is continued.

  According to the ninth aspect, even when a failure occurs in the second measurement unit (5; 25), it is possible to continue the operation of the plurality of power conversion circuits (1).

  In the power conversion system (100; 200) according to the tenth aspect, in the third aspect, the control unit (20) controls, for each of the plurality of power conversion circuits (1), a corresponding first measurement unit (5; Control is performed so that the measured value in 25) approaches the target value. The failure detection unit (21) operates as follows when the measurement unit is not in a failure state. That is, the failure detection unit (21) performs the first measurement when any of the plurality of first measurement units (5; 25) satisfies the condition that the difference between the measurement value and the target value is equal to or more than the threshold value. The power conversion circuit (1) corresponding to the unit (5; 25) is detected as a power failure conversion circuit under fault. The failed power conversion circuit is a power conversion circuit in which a failure has occurred.

  According to the tenth aspect, it is possible to detect the occurrence of a failure in the power conversion circuit (1), and it is possible to identify the power conversion circuit (1) in which the failure has occurred. As a result, the control unit (20) can cause the plurality of power conversion circuits (1) to perform an operation corresponding to the power conversion circuit (1) in which the failure has occurred.

  In the power conversion system (100; 200) according to the eleventh aspect, in the tenth aspect, the control unit (20) causes the operation of the power conversion circuit to be failed among the plurality of power conversion circuits (1) to stop. , To continue the operation of the remaining power conversion circuit.

  According to the eleventh aspect, although the maximum value of the power that can be output is reduced, it is possible to continue the output of power from the power conversion system (100; 200).

  In the power conversion system (100; 200) according to the twelfth aspect, in the first or second aspect, when the occurrence of a fault is detected by the fault detection unit (21), the control unit (20) The operation of the plurality of power conversion circuits is stopped.

  According to a twelfth aspect, the apparatus includes a device (a first measuring unit (5; 25), a second measuring unit (6; 26), or a power conversion circuit (1)) which may have a failure. Since all operations of the system are stopped, it is possible to improve the safety.

  A power conversion system (100; 200) according to a thirteenth aspect relates to the notification unit (23) for notifying a failure location detected by the failure detection unit (21) in any of the first to twelfth aspects, Further equipped.

  According to the thirteenth aspect, since the failure location is notified, it is possible to urge an external device or a user to take measures according to the failure location.

DESCRIPTION OF SYMBOLS 1 Power conversion circuit 20 Control part 21 Failure detection part 23 Notification part 31, 32 Power supply side terminal (1st terminal)
41, 42 Bus side terminal (second terminal)
5, 51-53 1st current measurement part (1st measurement part)
6 Second current measurement unit (second measurement unit)
25, 251-253 1st voltage measurement part (1st measurement part)
26 Second voltage measurement unit (second measurement unit)
100 power conversion system 200 power conversion system C1 capacitor (first capacitor)
C2 capacitor (second capacitor)

Claims (13)

A plurality of power conversion circuits electrically connected in parallel between the pair of first terminals and the pair of second terminals to convert the input voltage into a desired voltage;
A control unit that controls the operation of the plurality of power conversion circuits;
The measurement values of a plurality of first measurement units provided to correspond to the plurality of power conversion circuits in one-to-one correspondence and respectively measuring the current flowing through the corresponding power conversion circuits, and the currents flowing through the pair of first terminals A failure detection unit that detects which one of the plurality of first measurement units, the second measurement unit, and the plurality of power conversion circuits has a failure from the measurement values of the second measurement unit to be measured;
Power conversion system. The first capacitor provided in each is electrically connected in series between the pair of first terminals, and the second capacitor provided in each is electrically connected in series between the second terminals in the pair, A plurality of power conversion circuits that convert a voltage input through one of the second capacitors into a desired voltage and output the voltage from the other of the first and second capacitors;
A control unit that controls the operation of the plurality of power conversion circuits;
Measurement values of a plurality of first measurement units provided to correspond to the plurality of power conversion circuits and respectively measuring voltages between the first capacitors of the corresponding power conversion circuits, and the pair of first measurement units Based on the measurement value of the second measurement unit that measures the voltage between the terminals, it is detected which of the plurality of first measurement units, the second measurement unit, and the plurality of power conversion circuits has a failure. A failure detection unit,
Power conversion system. The failure detection unit is configured such that the difference between the sum of the measurement values of the plurality of first measurement units and the measurement value of the second measurement unit is equal to or greater than a predetermined determination threshold, The power conversion system according to claim 1 or 2, wherein it is detected that a measurement unit failure state in which a failure occurs in any of the second measurement units is detected. The control unit controls, for each of the plurality of power conversion circuits, the measurement value of the corresponding first measurement unit approaches a target value,
The failure detection unit is in the failure state of the measurement unit, and any one of the plurality of first measurement units satisfies the condition that the difference between the measurement value and the target value is equal to or more than a threshold value. The power conversion system according to claim 3, wherein the first measurement unit satisfying the condition is detected as a failure measurement unit in which a failure has occurred. The power conversion system according to claim 4, wherein the control unit stops the operation of the power conversion circuit corresponding to the failure measurement unit among the plurality of power conversion circuits, and continues the operation of the remaining power conversion circuits. The power conversion system according to claim 4 or 5, wherein the control unit stops the operation of all of the plurality of power conversion circuits when the number of the failure measurement units is two or more. The control unit is a measurement value by the second measurement unit and a measurement value by a first measurement unit other than the failure measurement unit among the plurality of first measurement units, instead of the measurement value of the failure measurement unit. The power conversion system according to claim 4, wherein the operation of the power conversion circuit corresponding to the failure measurement unit is continued using the value calculated from. The failure detection unit is in a failure state of the measurement unit, and when any of the plurality of first measurement units does not satisfy the condition, a failure occurs in the second measurement unit. The power conversion system according to claim 4 which detects that it is a measurement part. The control unit continues the operation of the plurality of power conversion circuits using values calculated from the measurement values of the plurality of first measurement units instead of the measurement values of the second measurement unit. Power conversion system as described. The control unit controls, for each of the plurality of power conversion circuits, the measurement value of the corresponding first measurement unit approaches a target value,
The failure detection unit is not the measurement unit failure state, and any one of the plurality of first measurement units satisfies the condition that the difference between the measurement value and the target value is equal to or more than the threshold value. The power conversion system according to claim 3, wherein the power conversion circuit corresponding to the satisfying first measurement unit is detected as a failed power conversion circuit in which a failure has occurred. The power conversion system according to claim 10, wherein the control unit stops the operation of the power conversion circuit under fault among the plurality of power conversion circuits and continues the operation of the remaining power conversion circuits. The power conversion system according to claim 1 or 2, wherein the control unit stops the operation of all of the plurality of power conversion circuits when occurrence of a failure is detected in the failure detection unit. The power conversion system according to any one of claims 1 to 12, further comprising: a notification unit that notifies a failure point detected by the failure detection unit.

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