JP2007049837A - Controller for power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converter that seldom produces trouble in a main circuit, wherein deterioration in a main circuit element, a smoothing capacitor, and a smoothing reactor due to thermal stress is determined from accumulated information on the state of inverter operation. <P>SOLUTION: A device is for controlling the power converter 1 that drives an induction motor by an inverter having a main circuit element. This device includes means 14 for detecting the temperature of the main circuit element of the inverter; means 20 for computing a first coefficient normalized from a switching frequency; means 21 for computing a second coefficient normalized from an output voltage command; means 22 for multiplying the first coefficient, second coefficient, and detected temperature to compute an amount of thermal stress; means 23 for determining the states of gate start and stop of the inverter; means 25 for adding and storing the amounts of thermal stress during the operating time of the inverter; means 26 for accumulating added values to compute an accumulated value; and means 27 that, when the computed accumulated value becomes equal to or higher than a predetermined value, determines that the main circuit element has been deteriorated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for controlling a power converter that drives an induction motor using a variable voltage and variable frequency inverter, and more particularly to a control apparatus for a power converter that takes into account deterioration protection of an inverter main circuit.

  Many inverters that drive induction motors by converting direct current to alternating current, particularly inverters that use high-speed, high-voltage switching elements in the main circuit, have been put to practical use in electric vehicles. As these inverters, a two-level inverter that outputs a two-level potential to an AC terminal, and an intermediate potential point between a high potential point and a low potential point of a DC power source, and selective ON / OFF control of a switching element There is a three-level inverter that outputs three-level potentials of a high potential point, a low potential point, and an intermediate potential point to an AC terminal. As a switching element of the main circuit, an insulated gate bipolar transistor (hereinafter referred to as “IGBT”) capable of high-frequency switching is applied to reduce current ripple and reduce magnetic noise of the motor.

  However, the high-frequency switching increases the heat loss of the switching element, and the deterioration of the switching element is a problem due to the long-term heat loss stress. Further, the same deterioration problem occurs in the smoothing capacitor and the smoothing reactor.

  Conventionally, a thermistor or the like is connected to the main circuit element to measure the temperature, and in combination with the loss data of the main circuit element prepared in advance, the chip temperature of the main circuit element is estimated. If it rises above, the main circuit is opened or the inverter operation is stopped, but this is only a protective operation due to the temperature rise during inverter operation, and the effect of continuous thermal stress on the main circuit is considered. Not done.

  In view of the above circumstances, an object of the present invention is to determine deterioration due to thermal stress of a main circuit element, a smoothing capacitor, and a smoothing reactor from accumulation of operating states of an inverter, and provide a power converter with less main circuit failure There is to do.

  The above problem is to detect the temperature of the main circuit element of the inverter, the smoothing capacitor, and the smoothing reactor, and determine the amount of thermal stress from the detected temperature and the normalized stress coefficient calculated from the inverter switching frequency and output voltage command. This thermal stress amount is multiplied during the inverter energization time from gate start to gate stop, and the calculation result is accumulated. This is achieved by determining that the main circuit has deteriorated when the value exceeds the value.

  That is, the present invention relates to a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element, and means for detecting the temperature of the main circuit element of the inverter, and switching of the inverter Means for calculating a first coefficient normalized from the frequency; means for calculating a second coefficient normalized from the output voltage command of the inverter; the calculated first coefficient and second coefficient; and the detection. Means for multiplying the temperature to calculate the amount of thermal stress; means for determining the gate start and stop states of the inverter; and the inverter operating time from the gate start to stop of the inverter. Means for accumulating and storing the accumulated value, means for accumulating the stored accumulated value and calculating the accumulated value, and the calculated accumulated value is predetermined. A control device for a power converter and a means for determining the deterioration of the main circuit element when it becomes higher.

  According to another aspect of the present invention, there is provided a device for controlling a power converter for driving an induction motor by a variable voltage, variable frequency inverter having a smoothing capacitor, a means for detecting the temperature of the smoothing capacitor of the inverter, Means for calculating a first coefficient normalized from the frequency; means for calculating a second coefficient normalized from the output voltage command of the inverter; the calculated first coefficient and second coefficient; and the detection. Means for multiplying the temperature to calculate the amount of thermal stress; means for determining the gate start and stop states of the inverter; and the inverter operating time from the gate start to stop of the inverter. Means for accumulating and storing the data, means for accumulating the stored accumulated value and calculating a cumulative value, and the calculated cumulative There is a controller of a power converter and a means for determining the deterioration of the smoothing capacitor when it becomes more than a predetermined value.

  According to another aspect of the present invention, there is provided an apparatus for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a smoothing reactor, and means for detecting the temperature of the smoothing reactor of the inverter, and switching of the inverter Means for calculating a first coefficient normalized from the frequency; means for calculating a second coefficient normalized from the output voltage command of the inverter; the calculated first coefficient and second coefficient; and the detection. Means for multiplying the temperature to calculate the amount of thermal stress; means for determining the gate start and stop states of the inverter; and the inverter operating time from the gate start to stop of the inverter. Means for accumulating and storing the accumulated value, means for accumulating the stored accumulated value and calculating the accumulated value, and the calculated accumulated value Value is the controller of a power converter and a means for determining the deterioration of the smoothing reactor when it becomes more than a predetermined value.

  Furthermore, the present invention provides a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element and a smoothing capacitor, and means for detecting the temperature of the main circuit element of the inverter; Means for detecting the temperature of the smoothing capacitor of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; and calculating a second coefficient normalized from the output voltage command of the inverter. Means for calculating the thermal stress amount of the main circuit element by multiplying the calculated first coefficient and second coefficient by the detected temperature of the main circuit element; and the calculated first coefficient And means for multiplying the second coefficient by the detected temperature of the smoothing capacitor to calculate the amount of thermal stress of the smoothing capacitor, and the gates of the inverter Means for determining a start and stop state, means for accumulating and storing the calculated thermal stress amount of the main circuit element during an inverter operation time from gate start to stop of the inverter, and the stored main circuit element Means for accumulating the accumulated value of the thermal stress amount and calculating the accumulated value, means for accumulating and storing the calculated thermal stress amount of the smoothing capacitor during the inverter operating time, and the stored smoothing capacitor A means for accumulating the integrated value of the thermal stress amount and calculating the accumulated value, and deterioration of the main circuit element when the accumulated value of the calculated thermal stress amount integrated value of the main circuit element exceeds a predetermined value. And means for determining deterioration of the smoothing capacitor when the cumulative value of the calculated integrated value of the thermal stress of the smoothing capacitor becomes equal to or greater than a predetermined value. A converter control apparatus.

  Further, the present invention provides a device for controlling a power converter for driving an induction motor by a variable voltage, variable frequency inverter having a main circuit element and a smoothing reactor, and means for detecting the temperature of the main circuit element of the inverter; Means for detecting the temperature of the smoothing reactor of the inverter, means for calculating a first coefficient normalized from the switching frequency of the inverter, and calculating a second coefficient normalized from the output voltage command of the inverter Means for calculating the thermal stress amount of the main circuit element by multiplying the calculated first coefficient and second coefficient by the detected temperature of the main circuit element; and the calculated first coefficient And means for multiplying the second coefficient by the detected temperature of the smoothing reactor to calculate a thermal stress amount of the smoothing reactor, Means for determining a start and stop state, means for accumulating and storing the calculated thermal stress amount of the main circuit element during an inverter operation time from gate start to stop of the inverter, and the stored main circuit element Means for accumulating the integrated value of the thermal stress amount and calculating the accumulated value; means for integrating and storing the calculated thermal stress amount of the smoothing reactor during the inverter operating time; and the stored smoothing reactor Means for accumulating the integrated value of the thermal stress amount and calculating the accumulated value, and determining that the main circuit element has deteriorated when the accumulated value of the integrated value of the thermal stress amount of the main circuit element exceeds a predetermined value. And a means for determining that the smoothing reactor has deteriorated when the cumulative value of the integrated thermal stress amount of the smoothing reactor becomes equal to or greater than a predetermined value. It is a device.

  And, in the apparatus for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a smoothing capacitor and a smoothing reactor, the present invention detects a temperature of the smoothing capacitor of the inverter; Means for detecting the temperature of the smoothing reactor of the inverter, means for calculating a first coefficient normalized from the switching frequency of the inverter, and calculating a second coefficient normalized from the output voltage command of the inverter Means for multiplying the calculated first and second coefficients by the detected temperature of the smoothing capacitor to calculate the amount of thermal stress of the smoothing capacitor; and the calculated first coefficient And means for multiplying the second coefficient by the detected temperature of the smoothing reactor to calculate the amount of thermal stress of the smoothing reactor; Means for determining a gate start and stop state of the inverter, means for integrating and storing the calculated thermal stress amount of the smoothing capacitor during an inverter operation time from the gate start to the stop of the inverter; Means for accumulating the cumulative value of the thermal stress amount of the smoothing capacitor and calculating the cumulative value; means for accumulating and storing the thermal stress amount of the smoothing reactor calculated during the inverter operating time; and Means for accumulating the integrated value of the thermal stress amount of the reactor for calculating the accumulated value, and deterioration of the smoothing capacitor when the accumulated value of the integrated value of the thermal stress of the smoothing capacitor exceeds a predetermined value And the smoothing reactor when the cumulative value of the integrated thermal stress amount of the smoothing reactor becomes equal to or greater than a predetermined value. A control device for a power converter and a means for determining the deterioration.

  Furthermore, the present invention is a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element, a smoothing capacitor and a smoothing reactor, and detects the temperature of the main circuit element of the inverter. Means for detecting the temperature of the smoothing capacitor of the inverter, means for detecting the temperature of the smoothing reactor of the inverter, and means for calculating the normalized first coefficient from the switching frequency of the inverter; Means for calculating a normalized second coefficient from the output voltage command of the inverter, and multiplying the calculated first coefficient and second coefficient by the detected temperature of the main circuit element. The means for calculating the amount of thermal stress, the calculated first coefficient and the second coefficient, and the detected temperature of the smoothing capacitor. The thermal stress amount of the smoothing reactor is calculated by multiplying the means for calculating the thermal stress amount of the condenser, the calculated first coefficient and second coefficient, and the detected temperature of the smoothing reactor. Means for determining the gate start and stop states of the inverter, means for accumulating and storing the calculated thermal stress amount of the main circuit element during the inverter operation time from the start to the stop of the inverter, Means for calculating a stored cumulative value of the accumulated thermal stress amount of the main circuit element; means for integrating and storing the calculated thermal stress amount of the smoothing capacitor during the inverter operation time; Means for accumulating the integrated value of the thermal stress amount of the condenser for calculating the cumulative value and the calculated thermal stress amount of the smoothing reactor Means for accumulating and storing data during the operation time of the data, means for accumulating the accumulated value of the stored thermal stress of the smoothing reactor of the inverter, and calculating the accumulated value, and integrating the thermal stress of the main circuit element Means for determining that the main circuit element has deteriorated when the accumulated value of the smoothing capacitor exceeds a predetermined value; and when the accumulated value of the thermal stress integrated value of the smoothing capacitor exceeds the predetermined value, A power converter comprising: means for determining deterioration of a capacitor for use; and means for determining deterioration of the smoothing reactor when a cumulative value of integrated thermal stress values of the smoothing reactor becomes equal to or greater than a predetermined value. It is a control device.

  According to the present invention, from the detected value of the temperature of the main circuit element of the power converter, the smoothing capacitor, and the smoothing reactor, and the coefficient normalized from the switching frequency to the power converter and the output voltage command, the power converter is obtained. It is possible to predict the deterioration of the main circuit element, smoothing capacitor, and smoothing reactor by calculating the amount of thermal stress of the power converter and taking into account the operating time of the power converter, and the power converter with less main circuit failure Can be provided.

The best mode for carrying out the present invention will be described.
Hereinafter, a case where the present invention is applied to an inverter-driven vehicle will be described as an embodiment of a control device for a power converter of the present invention.

  Example 1 will be described. In FIG. 1, DC power is supplied from an overhead wire 5 to a power converter 1 via a smoothing reactor (FL) 3 and a smoothing capacitor (FC) 2, and the power converter 1 is controlled by a variable voltage and a variable frequency. The output is supplied to an induction motor (IM) 4. The induction motor 4 is mechanically connected to a wheel of an electric vehicle (not shown), and the electric vehicle is controlled according to the output of the power converter 1.

  The switching (carrier) frequency 10 is a means for setting the switching frequency of the main circuit element of the power converter 1, and the output voltage command 11 is a means for generating a command for obtaining a predetermined output from the power converter 1. Normally, the switching frequency setting value, the output voltage command value, the current feedback of the induction motor 4, the voltage across the smoothing capacitor 2, etc. are input to the instantaneous output voltage command 12, and the voltage command value to be output instantaneously is created. The PWM signal creation 13 converts the pulse width-modulated PWM pulse, sends it to the power converter 1 as a gate signal, and performs variable voltage and variable frequency control.

  As described above, since the power converter 1 is switched at a high speed by the gate signal, heat loss occurs. Deterioration of the main circuit element proceeds due to stress due to the heat loss over time. Further, this switching also affects the smoothing capacitor and the smoothing reactor.

  Therefore, the thermal stress applied to the main circuit element of the power converter 1 is estimated from the set switching frequency, the output voltage state, and the temperature state of the element, etc. Therefore, it is possible to prevent a failure of the main circuit.

  In FIG. 1, the temperature detector 14 detects the temperature of the main circuit element of the power converter 1. Further, the normalization coefficient 1 calculation unit 20 calculates a normalization coefficient 1 (first coefficient) corresponding to the magnitude of the switching frequency 10. As the normalization coefficient 1, for example, as shown in FIG. 2, a value proportional to the switching frequency to be used is selected. In the case of an inverter-driven vehicle, since the switching frequency is about 500 Hz to 3 kHz, the normalization factor 1 may be set to a required value of K11 at F2 = 500 Hz and K10 at F2 = 3 kHz. Specific values such as the characteristic curve of FIG. 2 and K10 and K11 can be obtained in advance by experiments or the like according to the type of the main circuit element used.

  On the other hand, the normalization coefficient 2 (second coefficient) corresponding to the magnitude of the output voltage command 11 is calculated by the normalization coefficient 2 calculation unit 21. The output voltage is proportional to the gate signal that is the output of the PWM signal generation unit 13, and in the region where the output voltage is low, the number of pulses during one cycle of the AC voltage is large, and the number of pulses is controlled to decrease as the output voltage increases. The carrier frequency of the PWM signal has characteristics as shown in FIG. When the output voltage command value is to the left of the command value P5 (low output voltage region), the output voltage increases in a so-called asynchronous pulse state, and the carrier frequency increases proportionally with the increase in inverter frequency. However, in the asynchronous pulse, when the output voltage becomes high, an imbalance occurs in the phase voltage, and it becomes necessary to generate a pulse synchronized with the inverter output voltage. FIG. 4 shows an example in which five synchronous pulses are introduced, and switching from the asynchronous mode to the synchronous five pulses at the time of the command value P5. In the synchronization pulse, the voltage region where the number of pulses can be generated is limited, and it is necessary to switch to another synchronization pulse in order to continuously control the output voltage. FIG. 4 shows an example in which three synchronous pulses are introduced, and switching from synchronous five pulses to synchronous three pulses at time P3. Since an output voltage of about 98% can be output with three synchronous pulses, the mode is switched to a so-called one-pulse mode in which all voltages are output at P1. As shown in FIG. 4, the carrier frequency changes greatly every time the synchronization pulse is switched. Since this carrier frequency may be considered to be substantially equal to the number of times of switching of the main circuit element, the normalization coefficient 2 in FIG. 3 selects a characteristic that takes into account the change in the carrier frequency according to the pulse mode in FIG. ~ K23. Specific values such as the characteristic curve of FIG. 3 and K20 to K23 can be obtained in advance by experiments or the like according to the type of the main circuit element used.

  The normalization coefficient 1 and normalization coefficient 2 and the element temperature of the power converter 1 detected by the temperature detection unit 14 are input to the stress amount calculation unit 22 to calculate an instantaneous thermal stress amount. The element of the power converter 1 performs switching because the gate signal is applied. Therefore, the gate start 23 determines the gate start and stop states, and the energization time measurement unit 24 applies the gate signal. The time (inverter operating time) is measured, and the calculated thermal stress amount is integrated by the integrating circuit 25 only during the period when the gate signal is applied. Accumulation results are sequentially stored, and the cumulative value adding unit 26 adds the thermal stress amount integrated value to obtain the cumulative value.

  The accumulated value addition result is compared and determined by the deterioration determination circuit 27 with the predetermined value set as the deterioration determination value 28, and a deterioration determination signal 30 is output when the accumulated value exceeds the predetermined value. Further, the date and time data is input from the timer 28 to the deterioration determination circuit 27, and the date and time when the deterioration determination signal 30 is output is stored. The specific value of the predetermined value can be obtained by an experiment or the like in advance according to the type of the main circuit element used.

  As described above, in this embodiment, it is possible to estimate the amount of thermal stress from the operating state of the power converter and determine the deterioration of the main circuit element, thereby preventing the failure of the element.

  A second embodiment will be described. Another embodiment of the present invention is shown in FIG. FIG. 5 is the same as FIG. 1 except that the temperature detecting unit 15 detects the temperature of the smoothing capacitor FC2. The output of the temperature detection unit 15 is input to the stress amount calculation unit 22, and the thermal stress amount of the smoothing capacitor FC2 is calculated. Therefore, it is possible to determine the deterioration of the smoothing capacitor FC2 by the same processing as in FIG.

  A third embodiment will be described. Yet another embodiment of the present invention is shown in FIG. 6 is the same as FIG. 1 except that the temperature detecting unit 16 detects the temperature of the smoothing reactor FL3. The output of the temperature detection unit 16 is input to the stress amount calculation unit 22, and the thermal stress amount of the smoothing reactor FL3 is calculated. Therefore, it is possible to determine the deterioration of the smoothing reactor FL3 by the same processing as in FIG.

  Example 4 will be described. FIG. 7, FIG. 8, and FIG. 9 show still other embodiments of the present invention. That is, in the embodiments shown in FIGS. 1 to 6, the main circuit element, the smoothing capacitor, and the smoothing reactor are individually determined for deterioration, but may be configured by combining them. FIG. 7 shows an embodiment in which the deterioration of the main circuit element and the smoothing capacitor can be determined. As described above, the normalization coefficient 1 is calculated from the switching frequency to be used, and the normalization coefficient 2 is calculated from the magnitude of the output voltage command. Therefore, only one calculation circuit for the normalization coefficient 1 and the normalization coefficient 2 is required. In combination with the main circuit element detection temperature and the smoothing capacitor detection temperature, the respective stress amounts are calculated by 22 and 42, and the respective thermal stress amounts are integrated by the integration circuit 25 and the integration circuit (2) 45. The accumulated value is added by the accumulated value adding unit 26 and the accumulated value adding unit (2) 46, respectively. Deterioration of the main circuit element can be determined by the deterioration determination circuit 27, and deterioration of the smoothing capacitor can be determined by the deterioration determination unit (2) 47, and deterioration determination signals 30 and 50 can be output.

  FIG. 8 shows a modified example in which the deterioration judgment of the main circuit element and the smoothing reactor can be performed, and FIG. 9 shows another modified example in which the deterioration judgment of the smoothing capacitor and the smoothing reactor can be performed. The operation is the same as that shown in FIG.

  Example 5 will be described. FIG. 10 shows still another embodiment of the present invention. In FIG. 10, it is possible to determine the deterioration of the main circuit element, the smoothing capacitor, and the smoothing reactor. Also in FIG. 10, the calculation circuit of the normalization coefficient 1 and the normalization coefficient 2 may be one each, the main circuit element detection temperature, the smoothing capacitor detection temperature, the smoothing reactor detection temperature, the normalization coefficient 1 and the normalization coefficient The deterioration determination circuits 27, 47, and 67 can determine the deterioration states of the main circuit element, the smoothing capacitor, and the smoothing reactor by combining 2 respectively. Each operation is the same as in FIG.

1 is a block diagram of an inverter device according to a first embodiment. FIG. 5 is a diagram for explaining calculation of a normalization coefficient 1 in the first embodiment. FIG. 6 is a diagram for explaining calculation of a normalization coefficient 2 in the first embodiment. FIG. 6 is a diagram supplementing the calculation of the normalization coefficient 2 in the first embodiment. FIG. 5 is a block diagram of an inverter device according to a second embodiment. FIG. 6 is a block diagram of an inverter device according to a third embodiment. FIG. 6 is a block diagram of an inverter device according to a fourth embodiment. FIG. 9 is a block diagram of a modification of the inverter device according to the fourth embodiment. FIG. 10 is a block diagram of another modification of the inverter device according to the fourth embodiment. FIG. 10 is a block diagram of an inverter device according to a fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Power converter, 2 ... Smoothing capacitor, 3 ... Smoothing reactor, 4 ... Induction motor, 10 ... Switching frequency, 11 ... Output voltage command, 12 ... Instantaneous output voltage command, 13 ... PWM signal generation, 14 ... Main Circuit element temperature detection unit, 15 ... smoothing capacitor temperature detection unit, 16 ... smoothing reactor temperature detection unit, 20 ... normalization coefficient 1 calculation unit, 21 ... normalization coefficient 2 calculation unit, 22 ... stress amount calculation unit, 23 ... Gate start, 24 ... Energizing time measurement unit, 25 ... Integration circuit, 26 ... Cumulative value addition unit, 27 ... Deterioration detection circuit, 28 ... Deterioration determination value, 29 ... Timer

Claims (7)

In a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element,
Means for detecting the temperature of the main circuit element of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; and calculating a second coefficient normalized from the output voltage command of the inverter. Means for multiplying the calculated first coefficient and second coefficient by the detected temperature to calculate a thermal stress amount; means for determining a gate start and stop state of the inverter; and the calculation Means for accumulating and storing the thermal stress amount during the inverter operation time from the gate start to the stop of the inverter, means for accumulating the accumulated value and calculating the accumulated value, and the calculated accumulated value is predetermined. And a means for determining that the main circuit element has deteriorated when the value exceeds the value. In a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a smoothing capacitor,
Means for detecting the temperature of the smoothing capacitor of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; and calculating a second coefficient normalized from the output voltage command of the inverter. Means for multiplying the calculated first coefficient and second coefficient by the detected temperature to calculate a thermal stress amount; means for determining a gate start and stop state of the inverter; and the calculation Means for accumulating and storing the thermal stress amount during the inverter operation time from the gate start to the stop of the inverter, means for accumulating the accumulated value and calculating the accumulated value, and the calculated accumulated value is predetermined. And a means for judging that the smoothing capacitor has deteriorated when the value becomes equal to or greater than the value. In a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a smoothing reactor,
Means for detecting the temperature of the smoothing reactor of the inverter, means for calculating a first coefficient normalized from the switching frequency of the inverter, and calculating a second coefficient normalized from the output voltage command of the inverter Means for multiplying the calculated first coefficient and second coefficient by the detected temperature to calculate a thermal stress amount; means for determining a gate start and stop state of the inverter; and the calculation Means for accumulating and storing the thermal stress amount during the inverter operation time from the gate start to the stop of the inverter, means for accumulating the accumulated value and calculating the accumulated value, and the calculated accumulated value is predetermined. And a means for determining that the smoothing reactor has deteriorated when the value becomes equal to or greater than the value. In a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element and a smoothing capacitor,
Means for detecting the temperature of the main circuit element of the inverter; means for detecting the temperature of the smoothing capacitor of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; Means for calculating a second coefficient normalized from the output voltage command, and multiplying the calculated first coefficient and the second coefficient by the detected temperature of the main circuit element to cause thermal stress of the main circuit element; Means for calculating an amount; means for multiplying the calculated first coefficient and second coefficient by the detected temperature of the smoothing capacitor; and calculating a thermal stress amount of the smoothing capacitor; Means for determining the gate start and stop states, and the calculated thermal stress amount of the main circuit element based on the inverter operation time from the gate start to the stop of the inverter Means for accumulating and storing the accumulated time, means for accumulating the accumulated value of the stored thermal stress amount of the main circuit element, and calculating the accumulated value, and calculating the calculated thermal stress amount of the smoothing capacitor as the inverter operating time. Means for accumulating and storing the accumulated value, means for accumulating the accumulated value of the stored thermal stress amount of the smoothing capacitor, and calculating the accumulated value, and the calculated accumulated value of the accumulated thermal stress value of the main circuit element. Means for determining that the main circuit element has deteriorated when the value becomes equal to or greater than a predetermined value, and when the cumulative value of the calculated thermal stress integrated value of the smoothing capacitor becomes equal to or greater than a predetermined value, A power converter control device comprising: means for determining deterioration. In an apparatus for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element and a smoothing reactor,
Means for detecting the temperature of the main circuit element of the inverter; means for detecting the temperature of the smoothing reactor of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; Means for calculating a second coefficient normalized from the output voltage command, and multiplying the calculated first coefficient and the second coefficient by the detected temperature of the main circuit element to cause thermal stress of the main circuit element; Means for calculating an amount; means for multiplying the calculated first and second coefficients by the detected temperature of the smoothing reactor; and calculating a thermal stress amount of the smoothing reactor; and Means for determining the gate start and stop states, and the calculated thermal stress amount of the main circuit element based on the inverter operation time from the gate start to the stop of the inverter Means for accumulating and storing the accumulated time, means for accumulating the stored accumulated value of the thermal stress amount of the main circuit element, and calculating the accumulated value, and calculating the calculated thermal stress amount of the smoothing reactor as the inverter operating time. Means for accumulating and storing the accumulated time, means for accumulating the accumulated value of the stored thermal stress amount of the smoothing reactor and calculating the accumulated value, and the accumulated value of the accumulated thermal stress amount of the main circuit element is a predetermined value. Means for determining that the main circuit element is deteriorated at the time when the above is reached, and determining that the smoothing reactor is deteriorated when the cumulative value of the integrated thermal stress amount of the smoothing reactor becomes equal to or greater than a predetermined value. And a control device for the power converter. In a device for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a smoothing capacitor and a smoothing reactor,
Means for detecting the temperature of the smoothing capacitor of the inverter; means for detecting the temperature of the smoothing reactor of the inverter; means for calculating a first coefficient normalized from the switching frequency of the inverter; Thermal stress of the smoothing capacitor obtained by multiplying the calculated first coefficient and the second coefficient by the detected temperature of the smoothing capacitor by means for calculating the normalized second coefficient from the output voltage command Means for calculating an amount; means for multiplying the calculated first and second coefficients by the detected temperature of the smoothing reactor; and calculating a thermal stress amount of the smoothing reactor; and Means for determining a gate start and stop state, and the calculated thermal stress of the smoothing capacitor is stopped from the gate start of the inverter. Means for accumulating and storing the inverter during the operating time of the inverter, means for accumulating the stored integrated value of the thermal stress amount of the smoothing capacitor and calculating the accumulated value, and the smoothing reactor calculated during the inverter operating time Means for accumulating and storing the thermal stress amount, means for accumulating the stored thermal stress amount of the smoothing reactor and calculating the accumulated value, and the thermal stress amount integrated value of the smoothing capacitor. Means for determining that the smoothing capacitor has deteriorated when the accumulated value exceeds a predetermined value; and the smoothing reactor when the accumulated value of the integrated thermal stress amount of the smoothing reactor exceeds a predetermined value. And a power converter control device. In an apparatus for controlling a power converter that drives an induction motor by a variable voltage, variable frequency inverter having a main circuit element, a smoothing capacitor and a smoothing reactor,
Means for detecting the temperature of the main circuit element of the inverter, means for detecting the temperature of the smoothing capacitor of the inverter, means for detecting the temperature of the smoothing reactor of the inverter, and normalization from the switching frequency of the inverter Means for calculating the first coefficient, means for calculating a second coefficient normalized from the output voltage command of the inverter, detection of the calculated first coefficient, the second coefficient, and the main circuit element Means for calculating the amount of thermal stress of the main circuit element by multiplying by the temperature, and multiplying the calculated first coefficient and second coefficient by the detected temperature of the smoothing capacitor. The thermal stress amount of the smoothing reactor by multiplying the calculated first coefficient and the second coefficient by the detected temperature of the smoothing reactor. Means for calculating, means for determining the gate start and stop states of the inverter, means for integrating and storing the calculated thermal stress amount of the main circuit element during the inverter operation time from start to stop of the inverter; Means for calculating a cumulative value of the stored thermal stress amount integrated value of the main circuit element; means for integrating and storing the calculated thermal stress amount of the smoothing capacitor during the inverter operating time; Means for accumulating the accumulated value of the thermal stress amount of the smoothing capacitor and calculating the accumulated value; means for accumulating and storing the calculated thermal stress amount of the smoothing reactor during the inverter operating time; Means for accumulating the integrated value of the thermal stress amount of the smoothing reactor of the inverter and calculating the accumulated value, and the thermal stress of the main circuit element Means for determining that the main circuit element has deteriorated when the cumulative value of the integrated value exceeds a predetermined value; and when the cumulative value of the integrated value of the thermal stress of the smoothing capacitor exceeds the predetermined value, Means for determining that the smoothing capacitor has deteriorated, and means for determining that the smoothing reactor has deteriorated when the cumulative value of the integrated thermal stress amount of the smoothing reactor becomes equal to or greater than a predetermined value. A power converter control device.

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