JP6812775B2 - Power converter and power conversion method - Google Patents

Description

The present invention relates to a power conversion device and a power conversion method.

Conventionally, there are known power conversion devices that convert DC voltage supplied from high-side and low-side power input terminals and intermediate power input terminals between them into AC voltage. In such a power converter, capacitors are connected between the high side power input terminal and the intermediate power input terminal and between the low side power input terminal and the intermediate power input terminal, respectively, and the DC voltage is maintained and the supply voltage is supplied. (See, for example, Patent Documents 1 to 3).

Of these, in the power conversion device described in Patent Document 1, when a difference exceeding the reference threshold value occurs between the charging voltages of the two capacitors, an abnormality is detected and the charging voltage is equalized.
Patent Document 1 Patent No. 5591188 Specification Patent Document 2 Patent No. 5631445 Specification Patent Document 3 Patent No. 4489891

However, if a certain threshold value is used for the difference in charging voltage between capacitors, an abnormality may not be detected properly.

In the first aspect of the present invention, the charging voltage of the high side capacitor connected between the high side terminal and the intermediate terminal, the low side capacitor connected between the low side terminal and the intermediate terminal, and the high side capacitor. And, the first threshold is adjusted according to the DC voltage between the abnormality detection unit that detects an abnormality when the differential voltage of the charging voltage of the low-side capacitor exceeds the first threshold and the high-side terminal and the low-side terminal. A power converter comprising an adjusting unit is provided.

In the second aspect of the present invention, there is an adjustment step of adjusting the first threshold value according to the DC voltage between the high side terminal and the low side terminal, and the high side connected between the high side terminal and the intermediate terminal. Power conversion including an abnormality detection step for detecting an abnormality when the difference voltage between the charging voltage of the capacitor and the charging voltage of the low side capacitor connected between the low side terminal and the intermediate terminal exceeds the first threshold value. A method is provided.

The outline of the above invention does not list all the features of the present invention. Sub-combinations of these feature groups can also be inventions.

The power supply device which concerns on this embodiment is shown. Indicates an adjustment unit and an abnormality detection unit. An example of the relationship between the DC voltage between the high-side and low-side terminals and the first threshold value is shown. The configuration of the control unit for performing recovery is shown. The waveform of the voltage command value during the recovery operation is shown. The power conversion method according to this embodiment is shown. An example of the configuration of the computer according to this embodiment is shown.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the inventions claimed in the claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

FIG. 1 shows a power supply device 1 according to the present embodiment.
The power supply device 1 includes a power supply 10 and a power conversion device 2.

The power source 10 is a voltage source for DC power. For example, the power supply 10 may be a private generator such as a solar cell, or a circuit that rectifies AC power of a commercial frequency (for example, 50 Hz or 60 Hz) into DC power by a rectifier circuit including a rectifier diode and a capacitor. It may be.

The power conversion device 2 converts and outputs the DC voltage supplied from the power supply 10. In the present embodiment, the power conversion device 2 is described as converting a DC voltage into an AC voltage as an example, but other forms of conversion such as stepping up or lowering the DC voltage may be performed. The power converter 2 includes a high-side terminal P, an intermediate terminal M, a low-side terminal N, a power output terminal U, a high-side capacitor 21, a low-side capacitor 22, an output-side power converter 28, and a control device 3. To be equipped.

The high side terminal P is a terminal that receives an input of a voltage (for example, a positive voltage) higher than that of the low side terminal N and the intermediate terminal M. The high side terminal P is connected to the high side terminal of the power supply 10.

The intermediate terminal M is a terminal that receives an input of a voltage (for example, a voltage of zero) between the high side terminal P and the low side terminal N. The intermediate terminal M is connected between the high-side and low-side capacitors 21 and 22 described later.

The low side terminal N is a terminal that receives an input of a voltage (for example, a negative voltage) lower than that of the high side terminal P and the intermediate terminal M. The low side terminal N is connected to the low side terminal of the power supply 10.

The power output terminal U is a terminal that outputs the converted power by the output side power converter 28 described later. For example, when the power supply device 1 generates three-phase AC power, the power supply output terminal U may be connected to a single-phase inverter (not shown) of each phase. Further, the power output terminal U may be connected to a commercial power source to supply power. An output capacitor (not shown) may be connected between the power output terminal U and the low side terminal N.

The high-side capacitor 21 and the low-side capacitor 22 each hold a DC voltage to smooth the supply voltage. The high-side capacitor 21 is connected between the high-side terminal P and the intermediate terminal M, and the low-side capacitor 22 is connected between the low-side terminal N and the intermediate terminal M.

The output side power converter 28 is connected to the high side terminal P, the low side terminal N, and the intermediate terminal M to receive power from the high side capacitor 21 and the low side capacitor 22, and receives an AC voltage V _out from the power output terminal U. , AC current I _out power is output. In the present embodiment, as an example, the output side power converter 28 is a 3-level inverter, and converts the DC voltage from the high-side capacitor 21 and the low-side capacitor 22 into a 3-level AC voltage for output.

The control device 3 controls each part of the power supply device 1. The control device 3 includes a high-side charging voltage measuring unit 30, a low-side charging voltage measuring unit 31, a DC voltage measuring unit 32, an alternating current measuring unit 33, an abnormality detecting unit 35, an adjusting unit 37, and a control unit. It has 39 and.

The high-side charging voltage measuring unit 30 measures the charging voltage Vpm of the high-side capacitor 21, and the low-side charging voltage measuring unit 31 measures the charging voltage Vnm of the low-side capacitor 22. The high-side charging voltage measuring unit 30 and the low-side charging voltage measuring unit 31 may supply the measured charging voltages Vpm and Vnm to the abnormality detection unit 35 and the control unit 39, respectively.

The DC voltage measuring unit 32 measures the DC voltage Vpn between the high side terminal P and the low side terminal N. The DC voltage measuring unit 32 may measure the DC voltage Vpn based on the charging voltage Vpm of the high-side capacitor 21 and the charging voltage Vnm of the low-side capacitor 22. The DC voltage measuring unit 32 may supply the measured DC voltage Vpn to the adjusting unit 37.

The AC current measuring unit 33 measures the AC current I _out output from the output side power converter 28. The AC current measuring unit 33 may supply the measured AC current I _out to the control unit 39.

The abnormality detection unit 35 detects an abnormality when the difference voltage between the charging voltage Vpm of the high-side capacitor 21 and the charging voltage Vmn of the low-side capacitor 22 exceeds the first threshold value.

The adjusting unit 37 adjusts the first threshold value according to the DC voltage Vpn between the high side terminal P and the low side terminal N. The adjusting unit 37 may supply the adjusted first threshold value to the abnormality detecting unit 35.

The control unit 39 controls the power conversion device 2 so that the DC voltage Vpn is within the reference range. For example, the control unit 39 may control the DC voltage VPN supplied to the output side power converter 28 by adjusting the output power by the output side power converter 28 described later and / or by controlling the power supply 10. Here, the reference range of the DC voltage Vpn may be a range included in the operable operating range of the power converter 2 (for example, 500 to 1000 (V)), and is, for example, the same range as the operating range. Good.

Further, the control unit 39 may stop the power conversion device 2 in response to the detection of the abnormality by the abnormality detection unit 35. Further, the control unit 39 may recover from the abnormality by using the charging voltage Vpm, the charging voltage Vnm, the alternating current I _out, or the like according to the detection of the abnormality, and the power supply device 1 may perform the recovery from the abnormality during the recovery period. May be disconnected from the power supply destination system. The operation at the time of recovery will be described in detail later.

According to the above power supply device 1, an abnormality is detected when the difference voltage between the charging voltage Vpm of the high side capacitor 21 and the charging voltage Vmn of the low side capacitor 22 exceeds the first threshold value, and the high side terminal P and the low side The first threshold is adjusted according to the DC voltage Vpn between the terminals N. Therefore, the abnormality can be appropriately detected according to the magnitude of the DC voltage VPN.

FIG. 2 shows an adjusting unit 37 and an abnormality detecting unit 35.
The adjusting unit 37 may include an upper range threshold adjusting unit 371, a lower range threshold adjusting unit 372, a comparator 375, and a switch 376. The upper range threshold adjustment unit 371 and the lower range threshold adjustment unit 372 calculate the first threshold value ΔVth1 when the DC voltage Vpn is above or below the reference range (for example, the operation range).

Here, the upper range of the reference range is, for example, the upper range from the intermediate voltage of the reference range, that is, the upper half range in the present embodiment, but it may be a part of the range. Further, the lower range of the reference range is, for example, the lower range from the intermediate voltage of the reference range, that is, the lower half range in the present embodiment, but it may be a part of the range.

The upper range threshold value adjusting unit 371 has a first threshold value when the DC voltage Vpn is a second voltage higher than the first voltage in the upper range of the reference range as compared with the case where the DC voltage is the first voltage. May be made smaller. For example, the upper range threshold value adjusting unit 371 may make the first threshold value smaller as the DC voltage Vpn increases on the upper side within the reference range. In the present embodiment, as an example, the upper range threshold value adjusting unit 371 linearly lowers the first threshold value with respect to an increase in the DC voltage Vpn. The upper range threshold adjustment unit 371 may include a subtractor 3711, a multiplier 3712, an adder 3713, and a lower limit limiter 3714.

The subtractor 3711 subtracts the DC voltage VPN between the high terminal P and the low terminal N from the intermediate voltage Vm in the reference range for the DC voltage VPN between the high terminal P and the low terminal N. The intermediate voltage Vm may be stored in the adjusting unit 37 in advance. The DC voltage VPN may be supplied from the DC voltage measuring unit 32. In the present embodiment, when the DC voltage Vpn is above the reference range, the subtraction result may be a negative value and may be supplied to the multiplier 3712.

The multiplier 3712 multiplies the subtraction result of the intermediate voltage Vm and the DC voltage Vpn by the reference gain Gain1. Here, as an example in the present embodiment, when the DC voltage Vpn is the intermediate voltage Vm in the reference range, the first threshold value ΔVth1 becomes the maximum value ΔVth _MAX , and the first threshold value ΔVth1 becomes as the DC voltage Vpn deviates from the intermediate voltage Vm. It becomes smaller. The reference gain Gain1 may be a value obtained by multiplying the rate of change of the first threshold value ΔVth1 when the DC voltage Vpn is larger than the intermediate voltage Vm by (-1), and is a positive fixed value as an example. It may be a changeable value. The reference gain Gain 1 may be stored in the adjusting unit 37 in advance. The multiplication result may be a negative value and may be supplied to the adder 3713.

The adder 3713 adds the maximum value ΔVth _MAX of the first threshold value ΔVth1 and the multiplication result (negative value) by the multiplier 3712. As a result, a temporary first threshold value ΔVth1 corresponding to the current DC voltage Vpn is calculated so that the first threshold value ΔVth1 linearly decreases as the DC voltage Vpn rises from the intermediate voltage Vm. The calculation result may be supplied to the lower limit limiter 3714.

Here, the maximum value ΔVth _MAX of the first threshold value ΔVth1 is set based on a value obtained by subtracting the lower limit voltage from the upper limit voltage of the reference range for the DC voltage Vpn, and may be stored in the adjusting unit 37 in advance. For example, the maximum value ΔVth _MAX may be a value obtained by subtracting the lower limit voltage (500 (V) as an example) from the upper limit voltage (1000 (V) as an example) of the operating range of the power converter 2. In this case, when the DC voltage Vpn is the intermediate voltage Vm (750 (V) as an example), one of the charging voltages Vpm and Vmn of the high-side capacitor 21 and the low-side capacitor 22 is the upper limit voltage of the operating range, and the other is. Even if it is the lower limit voltage, these differential voltages ΔV become equal to or less than the first threshold value ΔVth1 (= ΔVth _MAX ), and no abnormality is detected. In this way, by increasing the first threshold value ΔVth1 when there is no risk of deterioration of output power quality and capacitor destruction, it is possible to prevent unnecessary abnormality detection and maintain power output. it can.

The lower limit value limiter 3714 outputs the lower limit value ΔVthH as the first threshold value ΔVth1 when the temporary first threshold value ΔVth1 calculated by the adder 3713 is smaller than the lower limit value ΔVthH, and in other cases, the provisional first threshold value ΔVthH is output. The threshold value ΔVth1 is output as it is as the first threshold value ΔVth1.

Here, the lower limit value ΔVthH may be the first threshold value ΔVth1 when the DC voltage Vpn is the upper limit voltage of the reference range. As a result, when the DC voltage Vpn is above the reference range, the first threshold value ΔVth1 becomes constant, so that the first threshold value ΔVth1 becomes too small, an abnormality is unnecessarily detected, and the power output stops. It is prevented from being stolen. Further, the lower limit value ΔVthH performs appropriate power conversion (DC / AC conversion as an example) from the operating lower limit voltage (250 (V) as an example) of one of the high side capacitor 21 and the low side capacitor 22. It may be set based on the value obtained by subtracting the lower limit voltage (230 (V) as an example) of one capacitor required for the above. As an example, the lower limit value ΔVthH may be calculated from the following formula.

Lower limit value ΔVthH = {(Lower voltage of operation of one capacitor)-(Lower voltage of one capacitor required for proper power conversion)} × 2

As a result, when the charging voltage of one capacitor is the lower limit voltage for operation and the charging voltage of the other capacitor is the lower limit voltage required for proper power conversion, that is, when proper power conversion is possible, the power is supplied. Output is secured.

The first threshold value ΔVth1 output from the lower limit value limiter 3714 may be supplied to the switch 376. The lower limit value limiter 3714 does not necessarily have to be provided in the upper range threshold value adjusting unit 371. When the lower limit value limiter 3714 is not provided, the countable result by the adder 3713 may be directly set as the first threshold value ΔVth1 and supplied to the switch 376.

The lower range threshold value adjusting unit 372 has a first threshold value when the DC voltage Vpn is a fourth voltage lower than the third voltage in the lower side of the reference range as compared with the case where the DC voltage is the third voltage. May be made smaller. For example, the lower range threshold value adjusting unit 372 may make the first threshold value smaller as the DC voltage Vpn becomes lower on the lower side within the reference range. In the present embodiment, as an example, the lower range threshold value adjusting unit 372 linearly lowers the first threshold value with respect to the lowering of the DC voltage Vpn. The lower range threshold adjuster 372 may include a subtractor 3721, a multiplier 3722, a subtractor 3723 and a lower limit limiter 3724.

The subtractor 3721 performs the same subtraction as the subtractor 3711 of the upper range threshold adjustment unit 371. However, in the present embodiment, when the DC voltage Vpn is below the reference range, the subtraction result may be a positive value and may be supplied to the multiplier 3722.

The multiplier 3722 multiplies the subtraction result of the intermediate voltage Vm and the DC voltage Vpn by the reference gain Gain2. Here, the reference gain Gain2 may be the rate of change of the first threshold value ΔVth1 when the DC voltage Vpn is smaller than the intermediate voltage Vm, and is a positive fixed value as an example, but is a value that can be changed by setting. You may. The reference gain Gain 2 may be stored in the adjusting unit 37 in advance. The multiplication result may be a positive value and may be supplied to the subtractor 3723.

The subtractor 3723 subtracts the multiplication result by the multiplier 3722 from the maximum value ΔVth _MAX of the first threshold value ΔVth1. As a result, a tentative first threshold value ΔVth1 corresponding to the current DC voltage Vpn is calculated so that the first threshold value ΔVth1 linearly decreases as the DC voltage Vpn decreases from the intermediate voltage Vm. The calculation result may be supplied to the lower limit limiter 3724.

The lower limit value limiter 3724 outputs the lower limit value ΔVthL as the first threshold value ΔVth1 when the temporary first threshold value ΔVth1 calculated by the subtractor 3723 is smaller than the lower limit value ΔVthL, and in other cases, the provisional first threshold value ΔVth1 is output. The threshold value ΔVth1 is output as it is as the first threshold value ΔVth1.

Here, the lower limit value ΔVthL may be the first threshold value ΔVth1 when the DC voltage Vpn is the lower limit voltage in the reference range. As a result, when the DC voltage Vpn is below the reference range, the first threshold value ΔVth1 becomes constant, so that the first threshold value ΔVth1 becomes too small, an abnormality is unnecessarily detected, and the power output stops. It is prevented from being lost. Further, the lower limit value ΔVthL may be set based on a value obtained by subtracting the operation upper limit voltage from the withstand voltage of one of the high side capacitor 21 and the low side capacitor 22. As an example, the lower limit value ΔVthL may be calculated from the following formula.

Lower limit value ΔVthL = {(withstand voltage of one capacitor)-(upper limit voltage of operation of one capacitor)} × 2

As a result, the power output is ensured when the charging voltage of one capacitor is the withstand voltage and the charging voltage of the other capacitor is the operation upper limit voltage, that is, when there is no risk of the capacitor being destroyed.

The first threshold value ΔVth1 output from the lower limit value limiter 3724 may be supplied to the switch 376. The lower limit value limiter 3724 does not necessarily have to be provided in the lower range threshold value adjusting unit 372. When the lower limit value limiter 3724 is not provided, the subtraction result by the subtractor 3723 may be directly set as the first threshold value ΔVth1 and supplied to the switch 376.

The comparator 375 compares the DC voltage Vpn with the intermediate voltage Vm in the reference range for the DC voltage Vpn. The DC voltage VPN may be supplied from the DC voltage measuring unit 32. The intermediate voltage Vm may be stored in the abnormality detection unit 35 in advance. The comparison result may be supplied to the switch 376.

The switch 376 selects the first threshold value ΔVth1 from the upper range threshold value adjusting unit 371 when the DC voltage Vpn is larger than the intermediate voltage Vm, that is, when the DC voltage Vpn is the upper voltage within the reference range. In other cases, the first threshold value ΔVth1 from the lower range threshold value adjustment unit 372 may be selected and supplied to the abnormality detection unit 35.

According to the above adjustment unit 37, the upper range threshold value adjustment unit 371 and the lower range threshold value adjustment unit 372 can calculate the first threshold value ΔVth1 corresponding to the DC voltage Vpn and supply it to the abnormality detection unit 35, respectively.

Here, when the DC voltage Vpn is small and the differential voltage is large, the voltage value of the capacitor with the smaller charging voltage among the high-side capacitor 21 and the low-side capacitor 22 becomes low, which is appropriate for the output-side power converter 28. There is a risk that the quality of output power will deteriorate because power conversion cannot be performed. As an example, if the voltage value of one of the capacitors becomes low, the waveform of the AC voltage may be distorted. On the other hand, according to the lower range threshold value adjusting unit 372, when the DC voltage Vpn is the fourth voltage lower than the third voltage in the lower range within the reference range, it is compared with the case where it is the third voltage. The first threshold value is reduced. As a result, when the DC voltage Vpn is small and the quality of the output power may deteriorate, the abnormality can be detected at an early stage, so that the quality of the output power can be prevented from deteriorating. Further, when the DC voltage Vpn is large and there is no risk of quality deterioration of the output power, it is possible to prevent an abnormality from being unnecessarily detected and maintain the power output.

On the other hand, if the DC voltage Vpn is large and the differential voltage is large, the capacitor with the larger charging voltage of the high-side capacitor 21 and the low-side capacitor 22 may be destroyed by applying a high voltage or the like. On the other hand, according to the upper range threshold value adjusting unit 371, when the DC voltage Vpn is the second voltage higher than the first voltage in the upper range within the reference range, it is the first voltage as compared with the case where it is the first voltage. 1 The threshold is reduced. As a result, when the DC voltage Vpn is large and there is a risk of capacitor destruction, it is possible to detect an abnormality at an early stage and protect the capacitor. Further, when the DC voltage Vpn is small and there is no risk of capacitor destruction, it is possible to prevent an abnormality from being unnecessarily detected and maintain the power output.

The adjusting unit 37 may always supply the first threshold value ΔVth1 or may supply the first threshold value ΔVth1 at each reference time interval. Further, the upper range threshold value adjusting unit 371 and the lower range threshold value adjusting unit 372 may non-linearly lower the first threshold value. The upper range threshold value adjusting unit 371 may make the first threshold value smaller when the DC voltage Vpn is larger than one or a plurality of reference threshold values as compared with the case where the DC voltage Vpn is smaller than the reference threshold value. Similarly, the lower range threshold value adjusting unit 372 may make the first threshold value smaller when the DC voltage Vpn is smaller than one or a plurality of reference threshold values as compared with the case where the DC voltage Vpn is larger than the reference threshold value.

The abnormality detection unit 35 may include a subtractor 354, an absolute value calculator 355, and a comparator 357.

The subtractor 354 subtracts the charging voltage Vmn of the low-side capacitor 22 from the charging voltage Vpm of the high-side capacitor 21 to calculate the difference voltage ΔV. The charging voltages Vpm and Vmn may be supplied from the high-side charging voltage measuring unit 30 and the low-side charging voltage measuring unit 31. The calculated difference voltage ΔV may be supplied to the absolute value calculator 355.

The absolute value calculator 355 calculates the absolute value of the difference voltage ΔV. The calculated absolute value of the differential voltage ΔV may be supplied to the comparator 357.

The comparator 357 compares the absolute value of the differential voltage ΔV with the first threshold value ΔVth1. The comparator 247 may detect an abnormality when the absolute value of the differential voltage ΔV is larger.

According to the above abnormality detection unit 35, when the current DC voltage Vpn is above the reference range, an abnormality is detected when the difference voltage ΔV is larger than the first threshold value ΔVth1 from the upper range threshold adjustment unit 371. Then, when the current DC voltage Vpn is below the reference range, an abnormality is detected when the difference voltage ΔV is larger than the first threshold value ΔVth1 from the lower range threshold value adjusting unit 372. The abnormality detection may be performed at all times or at reference time intervals.

FIG. 3 shows an example of the relationship between the DC voltage Vpn between the high-side and low-side terminals P and N and the first threshold value ΔVth1. Here, the horizontal axis in the figure shows the DC voltage Vpn, and the vertical axis shows the absolute value of the difference voltage ΔV between the high side capacitor 21 and the low side capacitor 22. The thick line in the figure indicates the first threshold value ΔVth1 for the differential voltage ΔV, and the region where the differential voltage ΔV is smaller than the first threshold voltage ΔVth1 indicates the region where the power conversion device 2 can operate normally. The shaded area where the differential voltage ΔV is large indicates the area where the power conversion device 2 should be stopped abnormally.

As shown in this figure, the first threshold value ΔVth1 for the differential voltage ΔV is an intermediate voltage Vm (750 (V) as an example) in which the DC voltage Vpn is in a reference range (an operating range of 500 to 1000 (V) as an example). When is, the maximum value is ΔVth _MAX (500 (V) as an example).

Further, when the DC voltage Vpn rises from the intermediate voltage Vm in the reference range to the upper limit voltage Vh (1000 (V) as an example) in the upper range of the reference range, the first threshold value ΔVth1 is maximum. The value decreases linearly with respect to the DC voltage Vpn from the value ΔVth _MAX to the lower limit value ΔVthH. The slope of the graph of the first threshold value ΔVth1 in this range is Gain1 × (-1) described above, and in this figure, Gain1 = − (ΔVth _MAX −ΔVthH) / (Vh−Vm) as an example. When the DC voltage Vpn exceeds the upper limit voltage Vh in the reference range, the first threshold value ΔVth1 becomes constant at the lower limit value ΔVthH.

Further, when the DC voltage Vpn drops from the intermediate voltage Vm in the reference range to the lower limit voltage Vl (500 (V) as an example) in the lower range of the reference range, the first threshold value ΔVth1 is set. It decreases linearly with respect to the DC voltage Vpn from the maximum value ΔVth _MAX to the lower limit value ΔVthL. The slope of the graph of the first threshold value ΔVth1 in this range is Gain2 described above, and in this figure, Gain2 = (ΔVth _MAX −ΔVthL) / (Vm−Vl) as an example. When the DC voltage Vpn is lower than the lower limit voltage Vl in the reference range, the first threshold value ΔVth1 becomes constant at the lower limit value ΔVthL.

FIG. 4 shows the configuration of the control unit 39 for performing recovery.
The control unit 39 recovers from the abnormality in response to the detection of the abnormality, controls the output side power converter 28 during the recovery period, and charges the charging voltage of the high side capacitor 21 and the low side capacitor 22. The amount of discharge from a higher capacitor may be increased. As an example, the control unit 39 may control the output side power converter 28 during the recovery period to discharge only the high side capacitor 21 and the low side capacitor 22 having a higher charging voltage. The control unit 39 may include a recovery operation command calculation unit 391 that outputs a recovery operation command for instructing execution / cancellation of recovery, and a recovery voltage command calculation unit 392 that outputs a voltage command at the time of recovery.

The recovery operation command calculation unit 391 may include a subtractor 3911, an absolute value calculation unit 3912, a comparator 3913, 3914, a flip-flop 3916, and an AND circuit 3917.

The subtractor 3911 calculates the difference voltage ΔV by subtracting the charging voltage Vmn of the low-side capacitor 22 from the charging voltage Vpm of the high-side capacitor 21. The charging voltages Vpm and Vmn may be supplied from the high-side charging voltage measuring unit 30 and the low-side charging voltage measuring unit 31. The difference voltage ΔV may be supplied to the absolute value calculator 3912 and the comparator 3928 in the recovery operation command calculation unit 391 described later, respectively.

The absolute value calculator 3912 calculates the absolute value of the difference voltage ΔV. The calculated absolute value of the differential voltage ΔV may be supplied to the comparators 3913 and 3914, respectively.

The comparator 3913 compares the absolute value of the differential voltage ΔV with the execution threshold value for executing the recovery. The execution threshold value may be a positive value and may be smaller than the above-mentioned lower limit values ΔVthL and ΔVthH. In the present embodiment, the execution threshold value is a fixed value (for example, 5, 0.05, etc.), but it may be a value that can be changed in advance by setting. The comparison result may be supplied to the flip-flop 3916.

The comparator 3914 compares the absolute value of the differential voltage ΔV with the release threshold value for canceling the recovery operation. The release threshold value may be a positive value and may be smaller than the above-mentioned lower limit values ΔVthL and ΔVthH. Further, the release threshold value may be smaller than the above-mentioned execution threshold value so that the recovery operation has hysteresis. In the present embodiment, the release threshold value is a fixed value (for example, 1, 0.01, etc.), but it may be a value that can be changed in advance by setting. The comparison result may be supplied to the flip-flop 3916.

The flip flop 3916 outputs an execution signal of the recovery operation when the absolute value of the differential voltage ΔV is larger than the execution threshold value, and maintains the output signal when the absolute value of the differential voltage ΔV is between the execution threshold value and the release threshold value. , The release signal is output when the absolute value of the differential voltage ΔV is less than the release threshold value. For example, the flip-flop 3916 is an RS type flip-flop circuit, and the set terminal (S) may be connected to the comparator 3913 and the reset terminal (R) may be connected to the comparator 3914. In this case, when the difference voltage ΔV is larger than the execution threshold value, the output of the execution signal is set, and when the difference voltage ΔV becomes less than the release threshold value, the output of the execution signal is reset. The output signal from the flip-flop 3916 may be supplied to the AND circuit 3917.

The AND circuit 3917 issues a recovery operation command instructing the execution of the recovery operation when the recovery operation execution signal is output from the flip-flop 3916 and the abnormality detection signal of the difference voltage ΔV is output from the abnormality detection unit 35. Output. In other cases, the AND circuit 3917 outputs a recovery operation command instructing the cancellation of the recovery operation.

According to the recovery operation command calculation unit 391 described above, when the absolute value of the difference voltage ΔV is larger than the execution threshold value, a command for instructing the execution of the recovery operation is output until it becomes smaller than the release threshold value.

The recovery voltage command calculation unit 392 may include a current limit calculation unit 393, a multiplier 3925, a lower limit value limiter 3926, an upper limit value limiter 3927, a comparator 3928, and a switch 3929.

During the recovery period, the current limit calculation unit 393 controls the output side power converter 28 to limit the magnitude of the alternating current I _out output from the output side power converter 28 to protect the element. For example, the current limit calculating unit 393, to the alternating current I _out outputted from the power conversion device 2 to reduce the AC current I _out when the reference is greater than, reduce the amplitude of the voltage command value for the output-side power converter 28 You can do it. The current limit calculation unit 393 may include a subtractor 3933, a PI controller 3934, a lower limit limiter 3935, and a subtractor 3936.

The subtractor 3933 subtracts the overcurrent threshold value from the AC current I _out output from the output side power converter 28 to calculate the excess amount of the AC current I _out with respect to the overcurrent threshold value, that is, the overcurrent amount. Here, the overcurrent threshold value is a value equal to or less than the target current (an example of the second threshold value), and is 100 (A) as an example in the present embodiment. The overcurrent threshold value may be stored in the control unit 39 in advance. The alternating current I _out may be supplied from the alternating current measuring unit 33. When the power output from the power conversion device 2 is converted into U-phase, V-phase, and W-phase AC power, the current measurement values of the three-phase AC power may be supplied. The calculated overcurrent amount may be supplied to the PI controller 3934.

The PI controller 3934 adjusts the overcurrent amount by performing proportional integration (PI) control so that the overcurrent amount smoothly approaches the target value (for example, zero). The adjusted overcurrent amount may be supplied to the lower limit limiter 3935.

The lower limit value limiter 3935 outputs the adjusted overcurrent amount to the subtractor 3936 as zero when the adjusted overcurrent amount is smaller than zero, and outputs the adjusted overcurrent amount as it is in other cases.

The subtractor 3936 calculates the reduction command ratio by subtracting the amount of overcurrent from the voltage command gain value (100% as an example) indicating the gain of the command voltage. For example, when the amount of overcurrent is 0 and 20, the reduction command ratio is calculated as 100% and 80%, respectively. The voltage command gain value may be stored in the control unit 39 in advance. The reduction command ratio may be supplied to the multiplier 3925.

The multiplier 3925 multiplies the reference command value for the AC voltage V _{out by} the reduction command ratio from the subtractor 3936. As a result, the amplitude of the reference command value is reduced by the reduction command ratio, and as a result, the magnitude of the AC current I _out is limited to the target current or less. The multiplication result may be supplied to the lower limit value limiter 3926 and the upper limit value limiter 3927, respectively.

The lower limit value limiter 3926 outputs the reference lower limit value as the reference lower limit value when the command value for the AC voltage V _out supplied from the multiplier 3925 is smaller than the reference lower limit value, and outputs the reference lower limit value as the AC voltage command value for high side discharge in other cases. The command value is output as it is as the AC voltage command value for high-side discharge. As a result, a high-side discharge AC voltage command value having a waveform in which the discharge ratio of the high-side capacitor 21 is increased is generated. In the present embodiment, as an example, the reference lower limit value is zero, but may be 0.05 (V) or the like. The AC voltage command value for high-side discharge may be supplied to the switch 3929.

The upper limit value limiter 3927 outputs the reference upper limit value as the low side discharge AC voltage command value when the command value for the AC voltage V _out supplied from the multiplier 3925 is larger than the reference upper limit value, and in other cases. The command value is output as it is as the low side discharge AC voltage command value. As a result, a low-side discharge AC voltage command value having a waveform in which the discharge ratio of the low-side capacitor 22 is increased is generated. In this embodiment, as an example, the reference upper limit value is zero, but it may be −0.05 (V) or the like. The low-side discharge AC voltage command value may be supplied to the switch 3929.

The comparator 3928 compares the differential voltage ΔV supplied from the subtractor 3911 with zero, and outputs “1” to the switch 3929 when the differential voltage ΔV is positive and “2” when the differential voltage ΔV is negative. To do.

The switch 3929 selects and outputs an AC voltage command value output from either the lower limit value limiter 3926 or the upper limit value limiter 3927 according to the output signal from the comparator 3928. For example, the switch 3929 outputs the AC voltage command value output from the lower limit value limiter 3926 when the output signal from the comparator 3928 is "1", and the upper limit value limiter when the output signal is "2". The AC voltage command value output from 3927 is output. The voltage command value output from the switch 3929 may be supplied to the control unit 39 and used for controlling the output side power converter 28.

According to the above recovery voltage command calculation unit 392, by outputting the high side or low side discharge AC voltage command value according to the positive / negative of the differential voltage ΔV, the high side capacitor 21 and the low side are output during the recovery period. Since the amount of discharge from the capacitor 22 having a higher charging voltage is increased, the difference voltage can be reduced at an early stage to eliminate the abnormality. Further, when the AC current I _out output from the power converter 2 is larger than the overcurrent threshold value, the element can be protected by reducing the amplitude of the voltage command value with respect to the output side power converter 28.

FIG. 5 shows the waveform of the voltage command value during the recovery operation. As shown in this figure, the AC voltage command value for high-side discharge may be a waveform obtained by extracting only the upper portion from the reference command value of the AC voltage. Further, the AC voltage command value for low-side discharge may be a waveform obtained by extracting only the lower portion from the reference command value of the AC voltage.

FIG. 6 shows a power conversion method according to the present embodiment. When the power supply device 1 starts operation, the DC voltage measuring unit 32 measures the DC voltage Vpn between the high side terminal P and the low side terminal N (step S1).

Next, the adjusting unit 37 adjusts the first threshold value ΔVth1 according to the measured DC voltage Vpn (step S3). For example, the adjusting unit 37 has a first threshold value ΔVth1 when the DC voltage Vpn is a second voltage higher than the first voltage in the upper range of the reference range as compared with the case where the DC voltage Vpn is the first voltage. May be made smaller. Further, the adjusting unit 37 sets the first threshold value ΔVth1 when the DC voltage Vpn is the fourth voltage lower than the third voltage in the lower side of the reference range as compared with the case where the DC voltage Vpn is the third voltage. You can make it smaller.

Next, the high-side charging voltage measuring unit 30 and the low-side charging voltage measuring unit 31 measure the charging voltages Vpm and Vmn of the high-side and low-side capacitors 21 and 22, and the abnormality detecting unit 35 calculates the difference voltage ΔV ( Step S5).

Next, the abnormality detection unit 35 determines whether or not an abnormality has been detected based on whether or not the difference voltage ΔV of the charging voltages Vpm and Vmn exceeds the first threshold value ΔVth1 (step S7). If it is determined in step S7 that no abnormality is detected (step S7; No), the power supply device 1 shifts the process to step S1 described above.

When it is determined in step S7 that the differential voltage ΔV exceeds the first threshold value ΔVth1 and an abnormality is detected (step S7; Yes), the control unit 39 stops the power conversion device 2 and powers the power supply device 1. Disconnect from the supply destination system (step S9).

Next, the control unit 39 determines whether or not the absolute value of the differential voltage ΔV is larger than the execution threshold value for executing the recovery (step S11). When the absolute value of the differential voltage ΔV is equal to or less than the execution threshold value (step S11; No), the control unit 39 shifts the process to step S23 described later without executing the recovery operation described later.

When the absolute value of the differential voltage ΔV is larger than the execution threshold value in step S11 (step S11; Yes), the control unit 39 shifts to the recovery mode (step S13) and executes the recovery operation (step S15). For example, the control unit 39 may control the output-side power converter 28 to increase the amount of discharge from the high-side capacitor 21 and the low-side capacitor 22 having a higher charging voltage. During the recovery period, the control unit 39 may disconnect the power supply device 1 from the power supply destination system.

Next, the control unit 39 determines whether or not the absolute value of the differential voltage ΔV is smaller than the release threshold value for canceling the recovery operation (step S17). When the absolute value of the differential voltage ΔV is equal to or greater than the release threshold value (step S17; No), the control unit 39 shifts the process to step S15 described above.

When the absolute value of the differential voltage ΔV is smaller than the release threshold value in step S17 (step S17; Yes), the control unit 39 cancels the recovery operation (step S19) and shifts from the recovery mode to the normal mode (step S17). S21).

Next, after the control unit 39 restarts the power conversion device 2 (step S23), the power supply device 1 shifts the process to the above-mentioned step S1.

The above steps S1 to S7 may be performed in another order, or at least a part thereof may be performed at the same time.

Further, in the above embodiment, the power conversion device 2 has been described as including the control unit 39 and the output side power converter 28, but these may not be provided. When the power converter 2 does not include the output side power converter 28, the output side power converter 28 may be provided in the power supply device 1 as a configuration separate from the power converter 2.

In addition, various embodiments of the present invention may be described with reference to flowcharts and block diagrams, wherein the block serves (1) the stage of the process in which the operation is performed or (2) the role of performing the operation. It may represent a section of the device it has. Specific stages and sections are implemented by dedicated circuits, programmable circuits supplied with computer-readable instructions stored on a computer-readable medium, and / or processors supplied with computer-readable instructions stored on a computer-readable medium. You can. Dedicated circuits may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuits are memory elements such as logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, flip-flops, registers, field programmable gate arrays (FPGA), programmable logic arrays (PLA), etc. May include reconfigurable hardware circuits, including.

The computer-readable medium may include any tangible device capable of storing instructions executed by the appropriate device, so that the computer-readable medium having the instructions stored therein is specified in a flowchart or block diagram. It will be equipped with a product that contains instructions that can be executed to create means for performing the operation. Examples of computer-readable media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer-readable media include floppy® disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), Electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray (RTM) disc, memory stick, integrated A circuit card or the like may be included.

Computer-readable instructions are assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or object-oriented programming such as Smalltalk, JAVA®, C ++, etc. Contains either source code or object code written in any combination of one or more programming languages, including languages and traditional procedural programming languages such as the "C" programming language or similar programming languages. Good.

Computer-readable instructions are applied locally to a general purpose computer, a special purpose computer, or the processor or programmable circuit of another programmable data processing device, or to a wide area network (WAN) such as the local area network (LAN), the Internet, etc. ) May be executed to create a means for performing the operation specified in the flowchart or block diagram. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers and the like.

FIG. 7 shows an example of a computer 2200 in which a plurality of aspects of the present invention may be embodied in whole or in part. The program installed on the computer 2200 can cause the computer 2200 to function as an operation or one or more sections of the device according to an embodiment of the invention, or the operation or the one or more. Sections can be run and / or the computer 2200 can be run a process according to an embodiment of the invention or a stage of such process. Such a program may be run by the CPU 2212 to cause the computer 2200 to perform certain operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

The computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphic controller 2216, and a display device 2218, which are interconnected by a host controller 2210. The computer 2200 also includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via the input / output controller 2220. There is. The computer also includes legacy input / output units such as the ROM 2230 and keyboard 2242, which are connected to the input / output controller 2220 via an input / output chip 2240.

The CPU 2212 operates according to the programs stored in the ROM 2230 and the RAM 2214, thereby controlling each unit. The graphic controller 2216 acquires the image data generated by the CPU 2212 in a frame buffer or the like provided in the RAM 2214 or itself so that the image data is displayed on the display device 2218.

The communication interface 2222 communicates with other electronic devices via the network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads the program or data from the DVD-ROM 2201 and provides the program or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from the IC card and / or writes programs and data to the IC card.

The ROM 2230 contains a boot program or the like executed by the computer 2200 at the time of activation, and / or a program depending on the hardware of the computer 2200. The input / output chip 2240 may also connect various input / output units to the input / output controller 2220 via a parallel port, serial port, keyboard port, mouse port, and the like.

The program is provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The program is read from a computer-readable medium, installed on a hard disk drive 2224, RAM 2214, or ROM 2230, which is also an example of a computer-readable medium, and executed by the CPU 2212. The information processing described in these programs is read by the computer 2200 and provides a link between the program and the various types of hardware resources described above. The device or method may be configured to implement the manipulation or processing of information in accordance with the use of computer 2200.

For example, when communication is executed between the computer 2200 and an external device, the CPU 2212 executes a communication program loaded in the RAM 2214, and performs communication processing on the communication interface 2222 based on the processing described in the communication program. You may order. Under the control of the CPU 2212, the communication interface 2222 reads and reads transmission data stored in a transmission buffer processing area provided in a recording medium such as a RAM 2214, a hard disk drive 2224, a DVD-ROM 2201, or an IC card. The data is transmitted to the network, or the received data received from the network is written to the reception buffer processing area or the like provided on the recording medium.

Further, the CPU 2212 causes the RAM 2214 to read all or necessary parts of a file or database stored in an external recording medium such as a hard disk drive 2224, a DVD-ROM drive 2226 (DVD-ROM2201), or an IC card. Various types of processing may be performed on the data on the RAM 2214. The CPU 2212 then writes back the processed data to an external recording medium.

Various types of information, such as various types of programs, data, tables, and databases, may be stored on recording media and processed. The CPU 2212 describes various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, and information retrieval described in various parts of the present disclosure with respect to the data read from the RAM 2214, and is specified by the instruction sequence of the program. Various types of processing may be performed, including / replacement, etc., and the results are written back to RAM 2214. Further, the CPU 2212 may search for information in a file, a database, or the like in the recording medium. For example, when a plurality of entries each having an attribute value of the first attribute associated with the attribute value of the second attribute are stored in the recording medium, the CPU 2212 specifies the attribute value of the first attribute. Search for an entry that matches the condition from the plurality of entries, read the attribute value of the second attribute stored in the entry, and associate it with the first attribute that satisfies the predetermined condition. The attribute value of the second attribute obtained may be acquired.

The program or software module described above may be stored on a computer 2200 or on a computer readable medium near the computer 2200. Also, a recording medium such as a hard disk or RAM provided within a dedicated communication network or a server system connected to the Internet can be used as a computer-readable medium, thereby providing the program to the computer 2200 over the network. To do.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention.

The order of execution of each process such as operation, procedure, step, and step in the device, system, program, and method shown in the claims, specification, and drawings is particularly "before" and "prior to". It should be noted that the output of the previous process can be realized in any order unless it is used in the subsequent process. Even if the scope of claims, the specification, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. It's not a thing.

1 power supply, 2 power converter, 3 controller, 10 power supply, 21 high side capacitor, 22 low side capacitor, 28 output side power converter, 30 high side charging voltage measuring unit, 31 low side charging voltage measuring unit, 32 DC voltage measuring unit, 33 AC current measuring unit, 35 anomaly detection unit, 37 adjustment unit, 39 control unit, 354 subtractor, 355 absolute value calculator, 357 comparer, 371 upper range threshold adjustment unit, 372 lower range threshold Adjuster, 375 comparer, 376 switch, 391 recovery operation command calculation unit, 392 recovery voltage command calculation unit, 393 current limit calculation unit, 3711 subtractor, 3712 multiplier, 3713 adder, 3714 lower limit limiter, 3721 subtractor , 3722 adder, 3723 subtractor, 3724 lower limit limiter, 3911 subtractor, 3912 absolute value calculator, 3913 comparer, 3914 comparer, 3916 flip flop, 3925 multiplier, 3926 lower limit limiter, 3927 upper limit limiter, 3928 comparer, 3929 switch, 3933 subtractor, 3934 PI controller, 3935 lower limit limiter, 3936 subtractor, 2200 computer, 2201 DVD-ROM, 2210 host controller, 2212 CPU, 2214 RAM, 2216 graphic controller, 2218 display device 22,20 input / output controller, 2222 communication interface, 2224 hard disk drive, 2226 DVD-ROM drive, 2230 ROM, 2240 input / output chip, 2242 keyboard, P high side terminal, M intermediate terminal, N low side terminal, U power output Terminal, Vmn DC voltage, Vmn charging voltage, Vpm charging voltage, V _out AC voltage, I _out AC current, ΔV differential voltage, ΔVth1 1st threshold

Claims (16)

With the high side capacitor connected between the high side terminal and the intermediate terminal,
A low-side capacitor connected between the low-side terminal and the intermediate terminal,
An abnormality detection unit that detects an abnormality when the difference voltage between the charging voltage of the high-side capacitor and the charging voltage of the low-side capacitor exceeds the first threshold value.
An adjusting unit that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal.
A control unit that controls the DC voltage so that it is within the reference range,
Equipped with a,
In the upper side of the reference range, when the DC voltage is a second voltage higher than the first voltage, the adjusting unit is compared with the case where the DC voltage is the first voltage. power converter decrease the threshold. With the high side capacitor connected between the high side terminal and the intermediate terminal,
A low-side capacitor connected between the low-side terminal and the intermediate terminal,
An abnormality detection unit that detects an abnormality when the difference voltage between the charging voltage of the high-side capacitor and the charging voltage of the low-side capacitor exceeds the first threshold value.
An adjusting unit that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal.
A control unit that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment unit, at the upper side of the said reference range, the power converter you smaller first threshold value as the DC voltage increases. The power conversion device according to claim 2 , wherein the adjusting unit linearly lowers the first threshold value with respect to an increase in the DC voltage on the upper side within the reference range. In the lower side of the reference range, when the DC voltage is a fourth voltage lower than the third voltage, the adjusting unit has the third voltage as compared with the case where the DC voltage is the third voltage. 1 The power conversion device according to any one of claims 1 to 3 , which reduces the threshold value. The power conversion device according to claim 1 , wherein the adjusting unit reduces the first threshold value as the DC voltage decreases on the lower side within the reference range. The power conversion device according to claim 5 , wherein the adjusting unit linearly lowers the first threshold value with respect to the decrease in the DC voltage on the lower side within the reference range. With the high side capacitor connected between the high side terminal and the intermediate terminal,
A low-side capacitor connected between the low-side terminal and the intermediate terminal,
An abnormality detection unit that detects an abnormality when the difference voltage between the charging voltage of the high-side capacitor and the charging voltage of the low-side capacitor exceeds the first threshold value.
An adjusting unit that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal.
A control unit that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment unit, the maximum value of the first threshold value, the power conversion apparatus to be set based on the value obtained by subtracting the lower limit voltage from the upper limit voltage of the reference range. With the high side capacitor connected between the high side terminal and the intermediate terminal,
A low-side capacitor connected between the low-side terminal and the intermediate terminal,
An abnormality detection unit that detects an abnormality when the difference voltage between the charging voltage of the high-side capacitor and the charging voltage of the low-side capacitor exceeds the first threshold value.
An adjusting unit that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal.
A control unit that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment unit, in case the DC voltage is at least one of above and below the reference range, the power conversion device shall be the constant first threshold.
With the high side capacitor connected between the high side terminal and the intermediate terminal,
A low-side capacitor connected between the low-side terminal and the intermediate terminal,
An abnormality detection unit that detects an abnormality when the difference voltage between the charging voltage of the high-side capacitor and the charging voltage of the low-side capacitor exceeds the first threshold value.
An adjusting unit that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal.
A control unit that controls the DC voltage so that it is within the reference range,
An output-side power converter that is connected to the high-side terminal, the low-side terminal, and the intermediate terminal, receives power from the high-side capacitor and the low-side capacitor, and outputs an output voltage.
With
In response to the detection of the abnormality, the control unit controls the output side power converter during the recovery period for recovering from the abnormality, and the charging voltage of the high side capacitor and the low side capacitor. There power converter Ru is greater amount of discharge from a higher capacitor. The ninth aspect of claim 9 , wherein the control unit controls the output-side power converter during the recovery period to discharge only a capacitor having a higher charging voltage among the high-side capacitor and the low-side capacitor. Power converter. The control unit controls the output side power converter during the recovery period to limit the magnitude of the output current output from the output side power converter to the second threshold value or less according to claim 9 or 10 . The power converter described. An adjustment step that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal,
The first threshold value is the difference voltage between the charging voltage of the high-side capacitor connected between the high-side terminal and the intermediate terminal and the charging voltage of the low-side capacitor connected between the low-side terminal and the intermediate terminal. Anomaly detection stage that detects anomalies when the value exceeds
A control stage that controls the DC voltage so that it is within the reference range,
Equipped with a,
In the adjustment step, when the DC voltage is a second voltage higher than the first voltage on the upper side within the reference range, the first voltage is compared with the case where the DC voltage is the first voltage. smaller to that power conversion method threshold. An adjustment step that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal,
The first threshold value is the difference voltage between the charging voltage of the high-side capacitor connected between the high-side terminal and the intermediate terminal and the charging voltage of the low-side capacitor connected between the low-side terminal and the intermediate terminal. Anomaly detection stage that detects anomalies when the value exceeds
A control stage that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment step, the upper side of the said reference range, smaller to that power conversion method the first threshold value as the DC voltage increases. An adjustment step that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal,
The first threshold value is the difference voltage between the charging voltage of the high-side capacitor connected between the high-side terminal and the intermediate terminal and the charging voltage of the low-side capacitor connected between the low-side terminal and the intermediate terminal. Anomaly detection stage that detects anomalies when the value exceeds
A control stage that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment step, the maximum value of the first threshold value, the power conversion method to set based on the value obtained by subtracting the lower limit voltage from the upper limit voltage of the reference range. An adjustment step that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal,
The first threshold value is the difference voltage between the charging voltage of the high-side capacitor connected between the high-side terminal and the intermediate terminal and the charging voltage of the low-side capacitor connected between the low-side terminal and the intermediate terminal. Anomaly detection stage that detects anomalies when the value exceeds
A control stage that controls the DC voltage so that it is within the reference range,
Equipped with a,
The adjustment step, when the DC voltage is at least one of above and below the reference range, the power conversion how to constant the first threshold value. An adjustment step that adjusts the first threshold value according to the DC voltage between the high-side terminal and the low-side terminal,
The first threshold value is the difference voltage between the charging voltage of the high-side capacitor connected between the high-side terminal and the intermediate terminal and the charging voltage of the low-side capacitor connected between the low-side terminal and the intermediate terminal. Anomaly detection stage that detects anomalies when the value exceeds
A control stage that controls the DC voltage so that it is within the reference range,
Equipped with a,
An output-side power converter that receives power from the high-side capacitor and the low-side capacitor and outputs an output voltage is connected to the high-side terminal, the low-side terminal, and the intermediate terminal.
In the control stage, in response to the detection of the abnormality, the output side power converter is controlled during the recovery period for recovering from the abnormality, and the charging voltage of the high side capacitor and the low side capacitor is charged. power conversion method but that Ru is greater amount of discharge from a higher capacitor.

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