JP2020058179A - Power output device - Google Patents

Abstract

To appropriately perform a predetermined process using a voltage of a capacitor detected by a voltage sensor regardless of a degree of deterioration of the smoothing capacitor.SOLUTION: A power output device includes: an inverter capable of converting DC power from a DC power supply into AC power and outputting the AC power; a smoothing capacitor provided between a positive electrode bus bar and a negative electrode bus bar of the inverter; a voltage sensor for detecting a voltage of the capacitor; and a control device for controlling a predetermined process on the basis of a voltage detected by the voltage sensor. The control device determines a degree of deterioration of the capacitor and adjusts parameters used in the predetermined process on the basis of a determined degree of deterioration.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power output device.

  Conventionally, this type of power output device includes an inverter, a smoothing capacitor connected between the positive and negative buses of the inverter, a resistor connected in parallel to the smoothing capacitor, and a normally open capacitor connected in series to the resistor. There has been proposed a device including a contactor of the type and a voltage detector connected in parallel to a smoothing capacitor (for example, see Patent Document 1). When the power to the inverter is turned off, the contactor is closed to discharge the electric charge stored in the smoothing capacitor, and the discharge time when the voltage detected by the voltage detector is attenuated by the discharging of the smoothing capacitor. Is measured and the progress of deterioration of the smoothing capacitor is detected by comparing the discharge time with a preset reference time. Thus, it is described that a reduction in the capacity of the smoothing capacitor can be detected and it is possible to determine whether or not replacement is necessary.

JP-A-6-165523

  However, in the above-described power output device, although it is possible to determine the necessity of replacement by detecting a decrease in the capacity of the smoothing capacitor, it is unnecessary until replacement, but the power output when the deterioration of the smoothing capacitor has progressed to some extent. No consideration is given to the effect on the processing performed by the device.

  A main object of the power output device of the present invention is to provide a power output device that appropriately performs a predetermined process using a voltage of a capacitor detected by a voltage sensor regardless of the degree of deterioration of a smoothing capacitor. I do.

  The power output device of the present invention employs the following means to achieve the above-described main object.

The power output device of the present invention,
An inverter capable of converting DC power from a DC power supply to AC power and outputting the AC power, a smoothing capacitor provided between a bus of a positive bus and a negative bus of the inverter, and a voltage sensor for detecting a voltage of the capacitor. A control device that performs a predetermined process based on a voltage detected by the voltage sensor,
The control device determines a degree of deterioration of the capacitor, and adjusts a parameter used in the predetermined process based on the determined degree of deterioration,
That is the gist.

  The power output device of the present invention includes a voltage sensor for detecting the voltage of a smoothing capacitor provided between the positive and negative buses of the inverter, and performs a predetermined process based on the voltage detected by the voltage sensor. In the process, the degree of deterioration of the capacitor is determined, and parameters used in the predetermined processing are adjusted based on the determined degree of deterioration. As a result, the predetermined processing using the voltage of the capacitor detected by the voltage sensor can be appropriately performed regardless of the degree of deterioration of the smoothing capacitor.

  In such a power output device of the present invention, the predetermined processing is feedback control for controlling the inverter so that a voltage of the capacitor detected by the voltage sensor approaches a target voltage, and the control device includes The gain used in the feedback control as the parameter may be adjusted based on the degree of deterioration. In this case, the gain may be adjusted so as to decrease as the deterioration of the capacitor progresses. In this way, hunting of the voltage of the capacitor can be suppressed, frequent occurrence of voltage abnormality between the buses due to progress of deterioration of the capacitor can be suppressed, and pulsation of the output current and distortion of the output current can be suppressed. it can.

  Further, in the power output device of the present invention, the predetermined processing is performed by determining whether or not the voltage of the capacitor detected by the voltage sensor is equal to or higher than a first threshold with a first detection time period. An overvoltage detection process for detecting an overvoltage, wherein the control device adjusts the first threshold value and / or the first detection time period used in the overvoltage detection process as the parameter based on a degree of deterioration of the capacitor. Is also good. In this case, the first threshold value may be adjusted so as to decrease as the deterioration of the capacitor progresses. Further, the first detection time limit may be adjusted so that the smaller the deterioration of the capacitor, the smaller the first detection time. In this way, it is possible to suppress a hardware failure due to an overvoltage between the buses accompanying the progress of the deterioration of the capacitor.

  Further, in the power output device according to the present invention, the predetermined processing is performed by determining whether or not the voltage of the capacitor detected by the voltage sensor is equal to or less than a second threshold with a second detection time period. An undervoltage detection process for detecting an undervoltage, wherein the control device adjusts the second threshold value and / or the second detection time period used in the undervoltage detection process as the parameter based on a degree of deterioration of the capacitor. You may do it. In this case, the second threshold value may be adjusted so as to increase as the deterioration of the capacitor progresses. Further, the second detection time limit may be adjusted so that the smaller the deterioration of the capacitor, the smaller the tendency. By doing so, it is possible to suppress power loss due to insufficient voltage between the buses due to progress of deterioration of the capacitor.

  In the power output device of the present invention, the power output device further includes a converter that converts the DC power of the DC power supply into a desired voltage and outputs the voltage between the buses, and the control device sets a target voltage so that the voltage of the capacitor changes. Controlling the converter by changing the voltage, measuring the time required until the voltage of the capacitor reaches the voltage corresponding to the target voltage after the change, and determining the degree of deterioration of the capacitor based on the measured required time. You may do it. This eliminates the need to provide a discharge resistor for discharging the capacitor in order to determine the degree of deterioration of the capacitor. Alternatively, in the power output device according to the present invention, the inverter is capable of performing a boosting operation in which a system power supply is connected to an output terminal via a reactor, boosts a voltage of the system power supply, and outputs the boosted voltage to the capacitor. The apparatus sets the target voltage larger than the voltage of the capacitor, and controls the inverter so that the voltage of the capacitor rises to the target voltage until the voltage of the capacitor reaches a voltage corresponding to the target voltage. May be measured, and the degree of deterioration of the capacitor may be determined based on the measured required time.

  In the power output device of the present invention, when the degree of deterioration of the capacitor has not reached the predetermined degree, the control device performs the predetermined process using a parameter adjusted based on the degree of deterioration. When the degree of deterioration of the capacitor reaches the predetermined degree, a predetermined warning may be output.

A second power output device according to the present invention includes:
A converter that converts a DC voltage from a DC power supply and outputs the DC voltage between the buses of the positive bus and the negative bus, an inverter that converts the DC voltage between the buses into an AC voltage and outputs the AC voltage, and is provided between the buses. A power output device including a smoothing capacitor, a voltage sensor that detects a voltage of the capacitor, and a deterioration diagnosis unit that diagnoses a degree of deterioration of the capacitor,
The deterioration diagnosis means controls the converter by changing a target voltage so that a voltage of the capacitor detected by the voltage sensor changes, and the voltage of the capacitor reaches a voltage corresponding to the changed target voltage. Measuring the required time until, and determining the degree of deterioration of the capacitor based on the measured required time,
That is the gist.

  The second power output device of the present invention controls the converter by changing the target voltage so that the voltage of the capacitor changes, and reduces the time required for the voltage of the capacitor to reach a voltage corresponding to the changed target voltage. The degree of deterioration of the capacitor is determined based on the measured required time. Accordingly, it is not necessary to provide a discharge resistor for discharging the capacitor in order to determine the degree of deterioration of the capacitor, so that the device can be further simplified.

FIG. 2 is a configuration diagram illustrating a schematic configuration of a power output device. It is a flowchart which shows an example of a capacitor deterioration diagnosis process. It is a flowchart which shows an example of a control parameter adjustment process. FIG. 4 is an explanatory diagram illustrating an example of a gain adjustment map. It is explanatory drawing which shows an example of the DC link overvoltage threshold value adjustment map. It is explanatory drawing which shows an example of a DC link undervoltage threshold adjustment map. It is explanatory drawing which shows an example of the map for detection time limit adjustment.

  An embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a power output device 10 of the present embodiment. The power output device 10 according to the present embodiment is configured as a system interconnection device that interconnects a power generation device 20 installed in a house or the like and the AC system power supply 1, and includes a power generation device 20, a DC / DC converter 21, It includes an inverter 22, a smoothing circuit 23, a parallel-off relay 24, a DC / DC converter 41, an auxiliary machine 42, and a control device 50. In this embodiment, a single-phase three-wire system is used as a power distribution system of the system power supply 1. However, the present invention can be applied to other systems such as a single-phase two-wire system and a three-phase three-wire system.

  The power generation device 20 generates DC power, and in the present embodiment, is configured as a fuel cell unit that generates power by an electrochemical reaction based on a fuel gas containing hydrogen and an oxidizing gas containing oxygen. The power generation device 20 may be configured by a power generator with a motor that generates power by power from a motor such as a gas engine, a solar power generation device, or the like.

  The DC / DC converter 21 has a switching element, a reactor, and the like (not shown). The DC power (for example, 100 V DC) from the power generation device 20 is boosted to a predetermined voltage (for example, 250 V DC), and the positive bus 31 and the negative bus of the inverter 22. 32 and (DC link unit 30). A smoothing capacitor 33 and a voltage sensor 34 for detecting the voltage of the capacitor 33 (capacitor voltage Vc) are connected between the positive bus 31 and the negative bus 32.

  The inverter 22 includes four transistors T11 to T22 and diodes D11 to D22 connected in anti-parallel to the transistors T11 to T22. The transistors T11 to T22 are arranged in pairs each of which is on the source side and the sink side with respect to the positive electrode bus 31 and the negative electrode bus 32. The output terminals 22a and 22a are connected to the connection points of the paired transistors. 22b is connected. One output terminal 22a of the inverter 22 is connected to the electric wire 2 of one phase (for example, U phase) of the system power supply 1, and the other output terminal 22b is connected to another phase (for example, V phase) of the system power supply 1. Are connected. Accordingly, the inverter 22 can convert the DC voltage from the DC / DC converter 21 into an AC voltage and supply the AC voltage to the system power supply 1 by performing switching control of the paired transistors.

  The smoothing circuit 23 removes high-frequency components of the output current of the inverter 22 and makes the output current a sine wave. The smoothing circuit 23 includes reactors 23a and 23b provided on the electric wires 2 and 3, and a capacitor 23c connected between the electric wires 2 and 3. One of the reactors 23a and 23b may be omitted.

  The disconnection relay 24 connects and disconnects the power output device 10 with the system power supply 1 and includes a first disconnection relay 24a and a second disconnection relay 24b. The first disconnection relay 24a is provided between the reactor 23a and a connection point of the capacitor 23c to the electric wire 2, and the second disconnection relay 24b is connected to the reactor 23b and the connection of the capacitor 23c to the electric wire 3. It is provided between the points.

  An auxiliary machine 42 and a control device 50 are connected between the positive bus 31 and the negative bus 32 via a DC / DC converter 41. As the auxiliary device 42, for example, a pump for supplying a fuel gas to the fuel cell unit, a blower for supplying air as an oxidizing gas, a pump for circulating hot water for recovering heat generated in the fuel cell unit, A radiator fan that blows air to a radiator provided in the circulation path of the stored hot water, a cooling fan that cools the inverter 22, and the like can be given.

  Although not shown, the control device 50 is configured as a microprocessor centered on a CPU. In addition to the CPU, the control device 50 includes a ROM for storing various programs, a RAM for temporarily storing data, an input port and an output port. Prepare. The control device 50 receives a capacitor voltage Vc from the voltage sensor 34 via an input port. On the other hand, a control signal from the control device 50 to the switching element of the DC / DC converter 21, a control signal to the switching element (transistors T11 to T22) of the inverter 22, and a control signal to the switching element of the DC / DC converter 41 On / off signals to the disconnection relay 24 (the first disconnection relay 24a, the second disconnection relay 24b), a display signal to the display device 51, and the like are output via the output port.

  Next, the operation of the power output device 10 thus configured will be described. When the power generation device 20 is in a state capable of generating power and outputs power to the system power supply 1 side, the control device 50 first sets the peak of the system voltage of the system power supply 1 to the target capacitor voltage Vc * which is the target voltage of the capacitor 33. A voltage slightly higher than the value (for example, 250 V) is set. Subsequently, a duty ratio Dc, which is an on / off ratio of the switching element of the DC / DC converter 21, is set based on the set target capacitor voltage Vc *, and the switching element of the DC / DC converter 21 is switched at the set duty ratio Dc. Control. Then, the duty ratio Di, which is the ratio of the on / off state of the switching element of the inverter 22, is obtained by feedback control using the gain K such that the voltage of the capacitor 33 (capacitor voltage Vc) detected by the voltage sensor 34 becomes the target capacitor voltage Vc *. And the switching control of the switching element of the inverter 22 is performed at the set duty ratio Di. Here, the gain K includes a proportional gain when controlling the inverter 22 by proportional control, and includes a proportional gain and an integral gain when controlling the inverter 22 by proportional integral control.

  Further, control device 50 performs an overvoltage detection process of detecting an overvoltage of DC link unit 30 by comparing capacitor voltage Vc with overvoltage threshold VO. In the overvoltage detection process, when the capacitor voltage Vc is equal to or higher than the overvoltage threshold VO and the state continues over the detection time limit TL1, it is determined that an overvoltage has occurred in the DC link unit 30. When the control device 50 determines that an overvoltage has occurred in the DC link unit 30, the DC / DC converter 21 and the inverter 22 are stopped and the power generation of the power generation device 20 is stopped to protect the DC / DC converter 21 and the inverter 22. I do.

  Further, control device 50 also performs an undervoltage detection process of detecting the undervoltage of DC link unit 30 by comparing capacitor voltage Vc with undervoltage threshold VU. In the undervoltage detection process, when the capacitor voltage Vc is equal to or lower than the undervoltage threshold VU and the state continues over the detection time limit TL2, it is determined that an undervoltage has occurred in the DC link unit 30. The control device 50 also stops the DC / DC converter 21 and the inverter 22 and stops the power generation of the power generation device 20 when determining that an undervoltage occurs in the DC link unit 30. Note that the detection time limit TL2 used in the undervoltage detection process may be the same as or different from the detection time limit TL1 used in the overvoltage detection process.

  Next, a process of diagnosing deterioration of the capacitor 33 will be described. FIG. 2 is a flowchart illustrating an example of a capacitor deterioration diagnosis process performed by the control device 50. This process is executed after the start-up of the power generation device 20 (fuel cell) is completed and before the connection to the system power supply 1 side (before the disconnection relay 24 is turned on).

  In the capacitor deterioration diagnosis process, first, control device 50 sets first voltage V1 as target capacitor voltage Vc * (step S100), and controls DC / DC converter 21 with the set target capacitor voltage Vc * (step S110). ). Here, the first voltage V1 can be set to, for example, a voltage slightly higher than the peak value of the system voltage of the system power supply 1 (for example, 250 V). Subsequently, the capacitor voltage Vc from the voltage sensor 34 is input (Step S120), and it is determined whether the input capacitor voltage Vc has reached the target capacitor voltage Vc * (first voltage V1) (Step S130). If it is determined that the capacitor voltage Vc has not reached the target capacitor voltage Vc *, the process returns to step S110 to repeat the processing. On the other hand, when it is determined that the capacitor voltage Vc has reached the target capacitor voltage Vc *, the target capacitor voltage Vc * is set to the second voltage V2 lower than the above-described first voltage V1 (step S140), and the timer T is measured. (Step S150), and waits until the capacitor voltage Vc reaches the target capacitor voltage Vc * (second voltage V2) while controlling the DC / DC converter 21 with the target capacitor voltage Vc * (steps S160 to S180). . When it is determined that the capacitor voltage Vc has reached the target capacitor voltage Vc *, the measurement of the timer T is terminated (step S190), and it is determined whether or not the measured value of the timer T is equal to or more than the deterioration determination threshold Tref (step S200). ). Here, the measurement value of the timer T indicates a time (discharge time) required for the capacitor voltage Vc to reach the second voltage V2 from the first voltage V1. An auxiliary machine 42 is connected via a DC / DC converter 41 to a positive bus 31 and a negative bus 32 to which the capacitor 33 is connected, and a DC / DC converter 41 to connect the target capacitor voltage Vc * to the first voltage V1. Is changed to a lower second voltage V2, the electric charge stored in the capacitor 33 is consumed by the auxiliary machine 42, so that the capacitor voltage Vc decreases. At this time, as the capacity of the capacitor 33 is smaller, the rate of decrease of the capacitor voltage Vc is faster. That is, the smaller the capacity of the capacitor 33, the shorter the discharge time of the capacitor 33. Therefore, by examining the length of the measurement value (discharge time) of the timer T, it is possible to determine the reduction in the capacity of the capacitor 33, that is, the degree of progress of the deterioration. The measurement of the discharge time of the capacitor 33 may be performed a plurality of times, and the degree of progress of the deterioration of the capacitor 33 may be determined based on the average value or the like.

  If it is determined that the measured value of the timer T is equal to or greater than the deterioration determination threshold Tref, it is determined that the capacitor 33 has not deteriorated enough to require replacement (step S210), and the measured value of the timer T (discharge time) is determined. Based on the above, a control parameter adjustment process for adjusting control parameters such as the gain K, the overvoltage threshold VO, the undervoltage threshold VU, and the detection time limit TL (detection time limits TL1 and TL2) is executed (step S220), and the capacitor deterioration diagnosis process is performed. To end. On the other hand, when it is determined that the measured value of the timer T is not equal to or more than the deterioration determination threshold Tref and is less than the deterioration determination threshold Tref, it is determined that the capacitor 33 has deteriorated enough to require replacement (step S230), and power generation is performed. The device 20 is stopped (step S240), and a warning that the capacitor 33 needs to be replaced is output to the display device 51 (step S250), and the capacitor deterioration diagnosis process ends.

  Next, the details of the control parameter adjustment processing performed in step S220 will be described. FIG. 3 is a flowchart illustrating an example of a control parameter adjustment process performed by the control device 50. In the control parameter adjustment processing, first, the control device 50 adjusts the gain K based on the measurement value (discharge time) of the timer T measured in steps S150 and S190 (step S300). In the present embodiment, the relationship between the gain K and the discharge time is determined in advance in the present embodiment and stored in the ROM of the control device 50 as a gain adjustment map. This is performed by deriving the gain K. FIG. 4 shows an example of the gain adjustment map. The gain K is adjusted to decrease as the discharge time becomes shorter, that is, as the degree of deterioration of the capacitor 33 increases. As a result, hunting of the capacitor voltage Vc can be suppressed, and pulsation of the output current and distortion of the output current can be suppressed. For this reason, it is possible to suppress the occurrence of an overvoltage or undervoltage abnormality of the DC link unit 30 due to frequent deterioration of the capacitor 33 and a decrease in the amount of power generation.

  Next, control device 50 adjusts overvoltage threshold VO based on the measured value (discharge time) of timer T (step S310). In the present embodiment, the adjustment of the overvoltage threshold VO is performed in such a manner that the relationship between the overvoltage threshold VO and the discharge time is obtained in advance and stored in the ROM of the control device 50 as an overvoltage threshold adjustment map. From the corresponding overvoltage threshold VO. FIG. 5 shows an example of the overvoltage threshold adjustment map. Subsequently, control device 50 adjusts undervoltage threshold VU based on the measured value (discharge time) of timer T (step S320). In the present embodiment, the adjustment of the undervoltage threshold VU is determined in advance in the relationship between the undervoltage threshold VU and the discharge time, and stored in the ROM of the control device 50 as an undervoltage threshold adjustment map, and the discharge time is given. And deriving the corresponding undervoltage threshold VU from the map. FIG. 6 shows an example of the undervoltage threshold adjustment map. Then, control device 50 adjusts detection time limit TL based on the measurement value (discharge time) of timer T (step S330), and ends the control parameter adjustment process. In the present embodiment, the adjustment of the detection time TL is performed in such a manner that the relationship between the detection time TL and the discharge time is obtained in advance and stored in the ROM of the control device 50 as a detection time adjustment map. , The corresponding detection time limit TL is derived. FIG. 7 shows an example of the detection time adjustment map.

  As shown in FIGS. 5 to 7, the overvoltage threshold VO is adjusted to be smaller as the discharge time is shorter, and the undervoltage threshold VU is adjusted to be larger as the discharge time is shorter. Is adjusted to be smaller as the discharge time is shorter. In this way, the overvoltage threshold VO, the undervoltage threshold VU, and the detection time limit TL are adjusted such that the shorter the discharge time, that is, the greater the degree of deterioration of the capacitor 33, the easier it is to detect the overvoltage or the undervoltage. In this way, as the degree of deterioration of the capacitor 33 increases, the detection sensitivity is increased, thereby suppressing a hardware failure.

  In the power output device 10 of the present embodiment described above, the degree of deterioration (discharge time) of the capacitor 33 is determined by performing feedback control of the inverter 22 so that the capacitor voltage Vc becomes the target capacitor voltage Vc *. The gain K used in the feedback control is adjusted based on the degree of deterioration. Specifically, the gain K is adjusted such that the larger the degree of deterioration of the capacitor 33 is, the smaller the gain is. As a result, hunting of the capacitor voltage Vc can be suppressed. As a result, frequent occurrence of overvoltage or undervoltage of the DC link unit 30 as deterioration of the capacitor 33 progresses can be suppressed, and pulsation of the output current and distortion of the output current can be suppressed.

  Further, in the power output device 10 of the present embodiment, an overvoltage detection process for detecting the overvoltage of the DC link unit 30 is performed by determining whether or not the capacitor voltage Vc * is equal to or higher than the overvoltage threshold VO by the detection time limit TL1. The overvoltage threshold VO and the detection time limit TL1 used in the overvoltage detection process are adjusted based on the degree of deterioration (discharge time). Specifically, the overvoltage threshold VO is adjusted so as to decrease as the degree of deterioration of the capacitor 33 increases, and the detection time limit TL1 is adjusted to decrease as the degree of deterioration of the capacitor 33 increases. As a result, it is possible to suppress a hardware failure accompanying the deterioration of the capacitor 33.

  Furthermore, in the power output device 10 of the present embodiment, an undervoltage detection process for detecting the undervoltage of the DC link unit 30 is performed by determining whether or not the capacitor voltage Vc * is equal to or less than the undervoltage threshold VU using the detection time limit TL2. The undervoltage threshold VU and the detection time limit TL2 used in the undervoltage detection process are adjusted based on the degree of deterioration (discharge time) of the capacitor 33. Specifically, the undervoltage threshold value VU is adjusted to increase as the degree of deterioration of the capacitor 33 increases, and the detection time limit TL2 is adjusted to decrease as the degree of deterioration of the capacitor 33 increases. As a result, loss of power due to deterioration of the capacitor 33 can be suppressed.

  Further, in the power output device 10 of the present embodiment, the DC / DC converter 21 is controlled by changing the target capacitor voltage Vc * from the first voltage V1 to the second voltage V2, and the changed capacitor voltage Vc is changed to the target capacitor voltage. The time required to reach Vc * (second voltage V2) (discharge time) is measured, and the degree of deterioration of capacitor 33 is determined based on the measured required time. This eliminates the need to provide a discharge resistor for discharging the capacitor 33 in order to determine the degree of deterioration of the capacitor 33.

  In the above-described embodiment, the gain K, the overvoltage threshold VO, the undervoltage threshold VU, and the detection time limit TL are adjusted based on the degree of deterioration (discharge time) of the capacitor 33. However, some adjustments are omitted. Is also good. Further, the parameter to be adjusted based on the degree of deterioration (discharge time) of the capacitor 33 is not limited to the above-described gain K, overvoltage threshold VO, undervoltage threshold VU, and detection time limit TL, but may be any processing performed based on the capacitor voltage Vc. Any parameter may be used.

  In the above-described embodiment, in the capacitor deterioration diagnosis processing, the DC / DC converter 21 is controlled by changing the target capacitor voltage Vc * from the first voltage V1 to the second voltage V2 lower than the first voltage V1. By measuring the required time (discharge time) required to decrease from the voltage V1 to the second voltage V2, the degree of deterioration of the capacitor 33 is determined based on the discharge time. However, the DC / DC converter 21 is controlled by changing the target capacitor voltage Vc * from the first voltage V1 to the third voltage V3 higher than this, and the capacitor voltage Vc rises from the first voltage V1 to the third voltage V3. By measuring a required time (charging time) required until the charging time, the degree of deterioration of the capacitor 33 may be determined based on the charging time. In this case, it may be determined that the shorter the charging time, the greater the degree of deterioration of the capacitor 33. The measurement of the charging time of the capacitor 33 may be performed a plurality of times, and the degree of deterioration of the capacitor 33 may be determined based on the average value or the like. Alternatively, the measurement of the discharge time of the present embodiment and the measurement of the charge time of this modification may be performed, and the two may be combined to determine the degree of deterioration.

  In the above-described embodiment, the DC / DC converter 21 is controlled so that the capacitor voltage Vc becomes the target capacitor voltage Vc *, and the time required for the capacitor voltage Vc to reach the target capacitor voltage Vc * is measured. Is determined. However, the inverter 22 is controlled instead of the DC / DC converter 21 so as to increase the target capacitor voltage Vc * so that the capacitor voltage Vc becomes the target capacitor voltage Vc *, and the capacitor voltage Vc reaches the target capacitor voltage Vc *. The time required to measure the deterioration degree of the capacitor 33 may be determined. The inverter 22 forms a boost chopper circuit by the reactor 23a, the diode D11 and the transistor T12 and the reactor 23b, the diode D21 and the transistor T22, so that the voltage of the system power supply 1 can be boosted and output to the capacitor 33.

  In the above-described embodiment, the auxiliary device 42 is connected to the positive bus 31 and the negative bus 32 (DC link unit 30) of the inverter 22 via the DC / DC converter 41. However, the output terminals 22a and 22b of the inverter 22 are connected. Auxiliary equipment may be connected between the disconnection relay 24 (the first disconnection relay 24a and the second disconnection relay 24b) via a DC / DC converter.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of “Means for Solving the Problems” will be described. In the embodiment, the inverter 22 corresponds to an “inverter”, the capacitor 33 corresponds to a “capacitor”, the voltage sensor 34 corresponds to a “voltage sensor”, and the control device 50 corresponds to a “control device”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of the means for solving the problem is as follows. This is merely an example for specifically describing a mode for carrying out the invention, and thus does not limit the elements of the invention described in the section of “Means for Solving the Problems”. That is, the interpretation of the invention described in the section of the means for solving the problem should be interpreted based on the description of the section, and the embodiment is an embodiment of the invention described in the section of the means for solving the problem. This is only a specific example.

  As described above, the embodiments for carrying out the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments at all, and various forms are possible without departing from the gist of the present invention. Of course, it can be implemented.

  INDUSTRIAL APPLICABILITY The present invention can be used in the manufacturing industry of power output devices.

  1 system power supply, 2, 3 wires, 10 power output device, 20 power generation device, 21 DC / DC converter, 22 inverter, 22a, 22b output terminal, 23 smoothing circuit, 23a, 23b reactor, 23c capacitor, 24 disconnect relay, 24a 1st disconnection relay, 24b 2nd disconnection relay, 30 DC link part, 31 positive electrode bus, 32 negative electrode bus, 33 capacitor, 34 voltage sensor, 41 DC / DC converter, 42 auxiliary equipment, 50 control device, 51 display Device, T11-T22 transistor, D11-D22 diode.

Claims (6)

An inverter capable of converting DC power from a DC power supply to AC power and outputting the AC power, a smoothing capacitor provided between a bus of a positive bus and a negative bus of the inverter, and a voltage sensor for detecting a voltage of the capacitor. A control device that performs a predetermined process based on a voltage detected by the voltage sensor,
The control device determines a degree of deterioration of the capacitor, and adjusts a parameter used in the predetermined process based on the determined degree of deterioration,
Power output device. The power output device according to claim 1,
The predetermined process is a feedback control that controls the inverter so that the voltage of the capacitor detected by the voltage sensor approaches a target voltage,
The control device adjusts a gain used in the feedback control as the parameter based on a degree of deterioration of the capacitor,
Power output device. The power output device according to claim 1 or 2,
The predetermined process is an overvoltage detection process of detecting an overvoltage between the buses by determining whether a voltage of the capacitor detected by the voltage sensor is equal to or more than a first threshold with a first detection time limit,
The control device adjusts the first threshold value and / or the first detection time period used in the overvoltage detection process as the parameter based on a degree of deterioration of the capacitor.
Power output device. The power output device according to any one of claims 1 to 3, wherein
The predetermined process is an undervoltage detection process of detecting an undervoltage between the buses by determining with a second detection time whether or not the voltage of the capacitor detected by the voltage sensor is equal to or less than a second threshold. Yes,
The control device adjusts the second threshold value and / or the second detection time period used in the undervoltage detection process as the parameter based on a degree of deterioration of the capacitor.
Power output device. The power output device according to any one of claims 1 to 4, wherein
A converter that converts the DC power of the DC power supply to a desired voltage and outputs the voltage between the buses,
The control device controls the converter by changing the target voltage so that the voltage of the capacitor changes, and measures a time required until the voltage of the capacitor reaches a voltage corresponding to the changed target voltage, Determining the degree of deterioration of the capacitor based on the measured required time;
Power output device. The power output device according to any one of claims 1 to 5, wherein
When the degree of deterioration of the capacitor has not reached the predetermined degree, the control device performs the predetermined processing using a parameter adjusted based on the degree of deterioration, and determines the degree of deterioration of the capacitor. When the degree has been reached, a predetermined warning is output,
Power output device.

Images