JP5454902B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device that drives an AC motor or a motor generator using a semiconductor element for power conversion such as an IGBT (Insulated Gate Bipolar Transistor), and particularly has a function of detecting the temperature of the semiconductor element with a temperature detection element. The present invention relates to a power conversion device.

  Conventionally, as in the power conversion device described in Patent Document 1, the detected temperature of a semiconductor element such as a switching element is output as an analog signal, converted into a digital signal, and then detected by a microcomputer (microcomputer). The circuit which recognizes is equipped.

  A method called PWM modulation (pulse width modulation) is widely known as a method for modulating an analog signal into a digital signal and outputting the digital signal. In this modulation method, for example, as described in Patent Document 2, the level of a reference waveform such as a triangular wave or sawtooth wave and an analog input signal are compared by a comparator or the like to generate a digital signal. Alternatively, a system such as using a duty conversion unit that generates a duty signal according to a digital value acquired by an A / D (analog / digital) converter is common.

  In the above-described power conversion device of Patent Document 1 that performs analog / digital conversion, an IGBT (Insulated Gate Bipolar Transistor) as a semiconductor element that outputs three-phase power of an inverter includes a diode as a temperature detection element. Has been. By converting the voltage of the diode into a digital signal and sending it to the microcomputer, the microcomputer can recognize the temperature of the IGBT, thereby enabling optimal control.

JP 2008-51775 A Japanese Patent Laid-Open No. 10-337036

  In the power conversion device of Patent Document 1 described above, a plurality of IGBTs may be connected and used in parallel. In this case, in order to control the power converter safely, it is necessary for the microcomputer to detect the temperature of the IGBT on the high temperature side in particular. For this reason, in Patent Document 1, only the temperature of the IGBT on the high temperature side is selected and sent to the microcomputer. However, since the detection characteristics of temperature detection elements such as diodes actually vary, it is impossible to accurately determine which IGBT temperature is higher simply by detecting the voltage of the temperature detection element. There's a problem.

  In order to properly detect the temperature of the IGBT on the high temperature side, it is necessary to take measures such as selecting a temperature detection element whose detection error is within an allowable range in advance, or improving variation of the temperature detection element itself, When these measures are implemented, there is a problem that the cost becomes high.

  Further, in order to accurately recognize the temperatures of the plurality of IGBTs, as shown in FIG. 1, two analog temperature signals 1 and 2 are respectively input to the individual duty conversion means 3 and 4, and the respective duty signals 5 and 5 are input. A configuration is also conceivable in which this is converted to 6 and input to the microcomputer 9 via the individual photocouplers 7 and 8. However, when such two signal transmission paths are provided, the number of photocouplers 7 and 8 is increased and the wiring area to the microcomputer 9 is increased, resulting in an increase in cost and the overall size. There is a problem of getting bigger.

  The present invention has been made in view of such circumstances, and can accurately detect temperatures of a plurality of semiconductor elements that perform power conversion, and can realize this with an inexpensive and small circuit. An object is to provide a conversion device.

In order to achieve the above object, the invention according to claim 1 has a converter having a plurality of semiconductor elements for boosting a DC voltage and a plurality of semiconductor elements for converting the boosted voltage in the converter into an AC voltage. In the power converter having a plurality of temperature detection elements that have both or any one of the inverters and that individually correspond to the plurality of semiconductor elements and generate a voltage according to the temperature of each semiconductor element, A plurality of duty conversion means that are individually connected to each voltage generation side of a plurality of temperature detection elements and convert each generated voltage into a duty signal having a different duty by pulse width modulation, and conversion by the plurality of duty conversion means Selecting means for selecting the duty signals having different duties, and selecting the duty signals having different duties by the selecting means. Connected to the output side of the selection means via a signal transmission element for transmitting the duty signal selected by the selection means. And a calculation control unit, wherein the generated voltages of the plurality of temperature detection elements are individually held between the plurality of temperature detection elements and the plurality of duty conversion units and output to the duty conversion unit. connect the holding means, the control means converts into two of the duty signal in two of the duty converting unit individually retained generated voltage by said holding means, select the two duty signals alternately arranged to control the selection of said selection means as the set of duty signal of the arrangement sequence is repeated several times in the same order, the arithmetic control means, said temperature detecting element A characteristic variation is stored, and temperature information detected from a duty signal input from the selection unit via the signal transmission element is corrected by the stored characteristic variation, and is selected by the selection unit. The same plurality of sets of duty signals are compared, and the duty signal is employed for the detection of the temperature information only when the difference between them is within a predetermined reference value.

  According to this configuration, the voltages indicating the temperatures of the plurality of semiconductor elements individually detected by the plurality of temperature detection elements are individually converted by the duty conversion means, and then selected by the selection means to be transmitted through one system. It is transmitted on the route. This eliminates the need for conventional signal transmission paths for multiple temperature information, reducing the signal transmission elements such as photocouplers and the wiring area for each path that were required in the subsequent stage of each signal transmission path. I can do it. As a result, the circuit of the temperature detection portion of the semiconductor element can be realized at a low cost and in a small size.

In addition , the temperature of each semiconductor element can be accurately detected.

Even if the voltage generated by the temperature detection element is affected by noise, the duty signal affected by the noise is not adopted as temperature information by the calculation control means, so the calculation control means may misrecognize the temperature information. Disappear. In other words, since only proper temperature information is employed in the arithmetic control means, the temperature information can be accurately recognized.

According to the second aspect of the present invention, there is provided a converter having a plurality of semiconductor elements for boosting a DC voltage and / or an inverter having a plurality of semiconductor elements for converting a boosted voltage in the converter into an AC voltage. And a plurality of temperature detection elements that are individually associated with the plurality of semiconductor elements and generate a voltage corresponding to the temperature of each of the semiconductor elements. A plurality of duty converters that are individually connected to the generator side and convert each generated voltage into duty signals having different duties by pulse width modulation, and duty signals having different duties converted by the plurality of duty converters The selecting means for selecting and the selecting means so that the duty signals having different duties are alternately selected. A control means for controlling the selection means; and an arithmetic control means connected to the output side of the selection means via a signal transmission element for transmitting the duty signal selected by the selection means. A holding means for individually holding the generated voltages of the plurality of temperature detecting elements and outputting them to the duty converting means is connected between each of the temperature detecting elements and the plurality of duty converting means. the converted individually retained generated voltage holding means into two of the duty signal in two of the duty converting unit, these two are arranged to select alternately the duty signal, the duty signal in this arrangement sequence set of controls the selection of the selection means as repeated multiple times in the same order of said operation control means stores the characteristic variation of the temperature detecting element, the selection The temperature information detected from the duty signal input from the stage via the signal transmission element is corrected by the stored characteristic variation, and the duty in the same plurality of sets selected by the selection means A duty signal that exceeds a predetermined reference value is excluded from the signals, and a duty signal that is not excluded is adopted for detection of the temperature information.

  According to this configuration, even if the voltage generated by the temperature detection element is affected by noise, the duty signal affected by the noise is not adopted as temperature information by the calculation control means. Will not be performed. In other words, since only proper temperature information is employed in the arithmetic control means, the temperature information can be accurately recognized.

According to a third aspect of the present invention, the duty converter includes a reference wave generator that generates a reference wave that repeats rising and falling at a constant period, a reference wave generated by the reference wave generator, and the plurality of temperatures. It comprises a plurality of operational amplification means for comparing the generated voltage of the detection element and converting the generated voltage into a duty signal.

  According to this configuration, since each duty conversion means performs duty conversion based on one reference wave, this conversion operation is synchronized. Therefore, when each duty signal is alternately selected by the selection means subsequent to each duty conversion means, for example, each duty signal can be alternately selected from the head at a predetermined cycle at the same timing. Therefore, when the duty signals are not synchronized, the selection positions of the duty signals are different, and the output waveform from the selection means is not disturbed.

According to a fourth aspect of the present invention, the duty converter further includes level shift means for offsetting the voltages generated by the plurality of temperature detecting elements and outputting the offset voltages to the plurality of operation amplification means, and the plurality of operation amplification means. By using the generated voltage offset by the level shift means for comparison with the reference wave, each duty signal converted by the plurality of operational amplification means has a different duty. It is characterized by.

  According to this configuration, it is possible to reliably determine the voltages generated by the plurality of temperature detection elements, and after this determination, the voltages can be converted into duty signals having different duties.

According to a fifth aspect of the present invention, the duty conversion unit further includes a second level shift unit that offsets a level of the reference wave generated by the reference wave generation unit, and is any one of the plurality of operational amplification units. By using the reference wave offset by the second level shift means for comparison with the generated voltage, each duty signal converted by the plurality of operational amplification means has a different duty. Features.

  According to this configuration, it is possible to reliably convert the voltages generated by the plurality of temperature detection elements into duty signals having different duties.

According to a sixth aspect of the present invention, the reference wave generating means generates a peak signal at the peak of the reference wave, and the control means synchronizes with the peak signal generated by the reference wave generating means, Selection control of duty signals having different duties from a plurality of operational amplification means is performed on the selection means.

  According to this configuration, the selection operation of the selection unit that selects the duty signals having different duties output from the plurality of operation amplification units and outputs the duty signals to the calculation control unit is performed in synchronization with the constant peak signal generated. Therefore, the duty signal can be properly acquired by the arithmetic control means. Further, since the duty signal is selected in synchronization with the peak signal that is constantly generated, it is possible to prevent erroneous selection.

According to a seventh aspect of the present invention, the calculation control means includes a counter that starts a count operation after resetting at a rising edge or a falling edge of the duty signal input from the selection means via the signal transmission element; An operation including a calculation for obtaining a duty value of the duty signal using the register value held in the register, the register holding the count value of the counter as a register value before the reset at the rising edge or the falling edge It is characterized in that the cycle of the duty signal is set longer than the cycle of the main loop of the arithmetic control means for performing the arithmetic processing.

  According to this configuration, since the cycle of the duty signal is longer than the cycle of the main loop of the calculation control unit, the calculation control unit reads the register value and calculates the duty of the duty signal in the main loop. This can be done without interruption.

According to an eighth aspect of the present invention, when any of the plurality of duty conversion means converts the voltage generated by the plurality of temperature detection elements into a duty signal, the duty ratio of the duty signal is less than 100%. It is characterized by restricting as follows.

  According to this configuration, if the duty ratio of the duty signal is less than 100%, there is always a rising edge or falling edge of the duty signal, so that the duty signal can always be identified by the arithmetic control means.

According to a ninth aspect of the present invention, the reference wave generating means generates a triangular wave that repeats rising and falling alternately at a constant slope as the reference wave, and falls or rises at the apex or lowest point of the triangular wave The second peak signal is generated, and the plurality of operational amplification units compare the generated voltages of the plurality of temperature detection elements including the generated voltage offset by the level shift unit with the triangular wave, thereby respectively changing the duty cycle. The control means generates at least two identical duty signals based on the second peak signal among duty signals having different duties output from the plurality of operational amplification means. The selection of the selection means is controlled so as to be continuous.

  According to this configuration, since at least two identical duty signals are continuous, the same “L” or “H” level is continuous at the time of switching the duty signal, and any duty signal in this continuous section. It is possible to eliminate the fact that the correct duty cannot be obtained by the calculation control means. That is, if two identical duty signals are continuous, for example, an “L” section between “H” and “H” can be detected, and thus the duty can be accurately obtained.

According to a tenth aspect of the present invention, the reference wave generating means generates a sawtooth wave that repeats rising and falling at a constant cycle as the reference wave, and the plurality of operational amplification means are offset by the level shift means. The generated voltage of the plurality of temperature detecting elements including the generated voltage is compared with the sawtooth wave to generate a duty signal having a different duty, and the control means is a duty having a different duty by the selection means. The selection means is controlled so that signals are alternately selected.

  According to this configuration, since the duty signals having different duties are alternately transmitted, it is possible to increase the transmission speed compared to the configuration in which at least two identical duty signals are continuous using the triangular wave according to claim 11. I can do it.

According to an eleventh aspect of the present invention, the duty conversion unit replaces the generated voltage of the plurality of temperature detection elements with a duty signal having a predetermined duty by pulse width modulation, and generates the plurality of temperature detection elements. It is characterized by comprising analog / digital conversion means for converting any one of the voltages into a digital signal and counter means for converting the width of the converted digital signal into a duty signal of a predetermined duty.

  According to this configuration, since the plurality of types of generated voltages are converted into digital signals by the analog / digital conversion means, the voltage of the reference wave for performing the pulse width modulation as in the means for converting to the duty signal by the pulse width modulation is reduced. Since there is no change, a duty signal having an appropriate duty can be obtained.

It is a block diagram which shows the structure of the temperature detection circuit of the conventional power converter device. It is a block diagram which shows the structure of the temperature detection circuit of the power converter device which concerns on 1st Embodiment of this invention. It is a circuit diagram which shows the structure of the power converter device of this invention. It is a figure which shows the arrangement pattern of the data signal input into the microcomputer of the temperature detection circuit of the power converter device of 1st Embodiment. It is a block diagram which shows the structure of the 1st modification of the temperature detection circuit of the power converter device which concerns on 1st Embodiment. It is a block diagram which shows the structure of the 2nd modification of the temperature detection circuit of the power converter device which concerns on 1st Embodiment. It is a figure which shows the arrangement pattern of the data signal input into the microcomputer of the temperature detection circuit of the power converter device of a 2nd modification. It is a block diagram which shows the structure of the temperature detection circuit of the power converter device which concerns on 2nd Embodiment of this invention. It is a signal waveform diagram for demonstrating operation | movement of the temperature detection circuit of the power converter device which concerns on 2nd Embodiment. It is a signal waveform diagram for demonstrating the arithmetic processing of the microcomputer of the temperature detection circuit of the power converter device which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the 1st modification of the temperature detection circuit of the power converter device which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the 2nd modification of the temperature detection circuit of the power converter device which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the temperature detection circuit of the power converter device which concerns on 3rd Embodiment of this invention. It is a signal waveform diagram for demonstrating operation | movement of the temperature detection circuit of the power converter device which concerns on 3rd Embodiment. It is a block diagram which shows the structure of the modification of the temperature detection circuit of the power converter device which concerns on 3rd Embodiment. It is a signal waveform diagram for demonstrating operation | movement of the temperature detection circuit of the power converter device which concerns on the modification of 3rd Embodiment. It is a block diagram which shows the structure of the temperature detection circuit of the power converter device which concerns on 4th Embodiment of this invention. It is a block diagram which shows the structure of the temperature detection circuit of the power converter device which concerns on 5th Embodiment of this invention. It is a block diagram which shows the detailed circuit structure of the reference wave production | generation part for sawtooth wave production | generation. It is a block diagram which shows the other structure of the duty converter of the temperature detection circuit of the power converter device of this embodiment. It is a signal waveform diagram for demonstrating the fault of the temperature detection circuit of the power converter device of 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.

(First embodiment)
FIG. 2 is a block diagram showing the configuration of the temperature detection circuit of the power conversion device according to the first embodiment of the present invention.

  2 includes a switching circuit 102 connected to the motor generator MG, an Ach (A channel) side duty converter (duty conversion means) 106a, and a Bch (B channel) side duty converter (duty). Conversion means) 106b, changeover switch (selection means) 104, control unit (control means) 110, photocoupler (signal transmission element) 112, microcomputer (arithmetic control means) 114, and buffer 116. Has been.

  Switching circuit 102 is provided in power conversion device 10 shown in FIG. 3. Power conversion device 10 includes converter 20 and inverter 30 that drives and controls motor generator MG, and is controlled by microcomputer 114. It is configured.

  A battery 40 is connected to the converter 20, and the battery 40 supplies DC power to the converter 20 and stores DC power regenerated from the converter 20. Converter 20 boosts the DC power supplied from battery 40 and outputs the boosted DC power to inverter 30, and steps down the DC power output from inverter 30 and outputs it to battery 40. Further, the converter 20 includes a capacitor 23, a reactor 24, an upper arm switching element (power conversion switching element) 21 which is a high voltage side semiconductor element, and a lower arm which is a high voltage GND (ground) side semiconductor element. Switching element (power conversion switching element) 22 and diodes D1 and D2.

  In these components, one end of the capacitor 23 and the reactor 24 is connected to the positive electrode side of the battery 40, and the other end of the capacitor 23 and the emitter terminal of the switching element 22 are connected to the negative electrode side. The switching element 21 and the switching element 22 are connected in series, and the other end of the reactor 24 is connected between them, that is, the emitter terminal of the switching element 21 and the collector terminal of the switching element 22.

  The collector terminal of the switching element 21 for the upper arm is connected to one end side of the inverter 30. The emitter terminal of the switching element 22 for the lower arm is connected to the other end side of the inverter 30. Between the collector and emitter of the switching element 21, a diode D <b> 1 that allows current to flow from the emitter side to the collector side is connected. Similarly, a diode D <b> 2 is also connected between the collector and emitter of the switching element 22.

  Motor generator MG is connected to inverter 30 and is driven by electric power supplied from battery 40. When working as a generator, AC power is output to the inverter 30.

  The inverter 30 includes a U phase, a V phase, and a W phase, and the U phase, the V phase, and the W phase are connected in parallel to the converter 20, and converts the DC power boosted by the converter 20 into a three-phase AC, Output to motor generator MG. When motor generator MG functions as a generator, AC power output from motor generator MG is converted to DC and output to converter 20. Furthermore, the inverter 30 includes a capacitor 31 for absorbing a surge voltage that also serves as a power storage, on the connection side with the converter 20.

  The U phase of the inverter 30 is formed by connecting a switching element 34 for the upper arm of the semiconductor element on the high voltage side and a switching element 35 for the lower arm of the semiconductor element on the high voltage GND side in series. Similarly, the switching element 36 for the upper arm and the switching element 37 for the lower arm are connected in the V phase, and the switching element 38 for the upper arm and the switching element 39 for the lower arm are connected in series in the W phase.

  Between the collectors and emitters of the respective switching elements 34 to 39, diodes D3 to D8 for passing a current from the emitter side to the collector side are respectively connected. An intermediate point of each UVW phase is connected to each phase end of each phase coil (not shown) of motor generator MG. Here, it is assumed that a power device such as an IGBT is used as the switching element included in each of the converter 20 and the inverter 30.

  Further, each of the switching elements 21 and 22 of the converter 20 and each of the switching elements 34 to 39 of the inverter 30 is such that when the upper arm switching element is on, the lower arm switching element is off and the upper arm switching element is off. In the off state, the microcomputer 114 performs switching control (on / off control) so that the lower arm switching element is turned on.

  According to the power conversion device 10, the DC power of the battery 40 is boosted by the converter 20 by the switching control of the switching elements 21 and 22 of the converter 20 and the switching elements 34 to 39 of the inverter 30 by the control unit 11. The motor generator MG is driven by this three-phase alternating current. On the other hand, when motor generator MG functions as a generator, AC power output from motor generator MG is converted into DC power by inverter 30, further stepped down by converter 20, and regenerated by battery 40.

  By the way, each switching element 34-39 of the inverter 30 of the power converter device 10 becomes the switching circuit 102 of the structure shown in FIG. 2 so that it may surround with the broken-line frame 102 on behalf of the switching element 35 in detail. .

  The switching circuit 102 includes two switching elements 35a and 35b connected in parallel between the motor generator MG and the earth (ground), and is individually associated with the switching elements 35a and 35b and indicated by alternate long and short dashed lines 120a and 120b. The two diodes 122a and 122b as temperature detecting elements packaged in one package, two constant current circuits 124a and 124b individually connected to the anode side of each diode 122a and 122b, and these constant current circuits 124a and 124b. And a resistor 126 connected between the base end of each of the switching elements 35a and 35b and the buffer 116. However, the power source 126 is the battery 40 via the converter 20.

  Here, one diode 122a is defined as the Ach side, and the other diode 122b is defined as the Bch side. A current corresponding to the temperature of the switching element 35a flows from the constant current circuit 124a to the diode 122a on the Ach side, and a current corresponding to the temperature of the switching element 35b is supplied to the diode 122b on the Bch side. It starts to flow from 124b. The anode end of the Ach-side diode 122a is wired to the Ach-side duty converter 106a, and the anode end of the Bch-side diode 122b is wired to the Bch-side duty converter 106b.

  The Ach-side duty converter 106a performs PWM modulation on the analog signal, which is the generated voltage on the Ach side, and converts it into an Ach duty signal (digital signal) AD having a duty of 0 to 49%. Output to the input terminal. The Bch-side duty converter 106b PWM-modulates an analog signal, which is a generated voltage on the Bch side, and converts the analog signal into a Bch duty signal (digital signal) BD having a duty of 51 to 100%. Output to the input terminal. That is, the Ach duty signal AD and the Bch duty signal BD are unique signals having different duties. FIG. 4A shows an example of the Ach duty signal AD and the Bch duty signal BD.

  The changeover switch 104 alternately selects the Ach or Bch duty signal AD or BD as shown in FIG. 4A according to the control of the control unit 110 and outputs it to the photocoupler 112. As a result, a data signal DS in which Ach or Bch duty signals AD or BD are alternately arranged is output to the microcomputer 114 via the photocoupler 112.

  The microcomputer 114 detects a different duty from the signal arrangement of the data signal DS to detect the Ach duty signal AD or the Bch duty signal BD, and the switching elements 35a and 35b, which are semiconductor elements, from the detected duty signals AD and BD. Detect the temperature of In response to this detection, the switching element 35a or 35b is controlled to be below a predetermined temperature via the buffer 116.

  Here, the diodes 122a and 122b, which are temperature detection elements, have characteristic variations at the time of manufacture, and therefore, the duty signals AD, BD, which are detection temperature information, also include errors. Therefore, the microcomputer 114 stores in advance that the characteristics of the diodes 122a and 122b vary, for example, the diode 122a has a 3% variation in output characteristics and the diode 122b has a 5% variation, and is detected from the duty signal AD of the Ach. 3% correction is performed on the detected temperature information, and 5% correction is performed on the temperature information detected from the Bch duty signal BD.

  In the power conversion apparatus 10 according to the first embodiment, as the temperature detection circuit 100 of the plurality of switching elements 35a and 35b, the voltage generation of each of the plurality of diodes 122a and 122b associated with the switching elements 35a and 35b. A plurality of duty converters 106a and 106b, which are individually connected to the side and convert each generated voltage into duty signals AD and BD having different duties by pulse width modulation, and each converted by the duty converters 106a and 106b. A selector switch 104 that selects duty signals AD and BD having different duties, and a control unit 110 that controls the selector switch 104 so that duty signals having different duties are alternately selected by the selector switch 104. did.

  As a result, voltages indicating the temperatures of the plurality of switching elements 35a and 35b that are individually detected by the plurality of diodes 122a and 122b are individually converted by the duty converters 106a and 106b and then selected by the changeover switch 104. Are transmitted through a single signal transmission path. This eliminates the need for conventional signal transmission paths for multiple temperature information, reducing the signal transmission elements such as photocouplers and the wiring area for each path that were required in the subsequent stage of each signal transmission path. I can do it. Thereby, the temperature detection circuit 100 of the switching elements 35a and 35b in the power conversion device 10 can be realized at low cost and in a small size.

  Further, the microcomputer 114 as a calculation control unit connected to the output side of the changeover switch 104 via the photocoupler 112 stores the characteristic variation of each of the diodes 122a and 122b, and from the changeover switch 104 via the photocoupler 112. The temperature information detected from the input duty signal is corrected by the stored characteristic variation. Thereby, the temperature of each diode 122a, 122b can be detected accurately.

  Further, as in the temperature detection circuit 100-1 shown in FIG. 5, a hold as a holding unit that holds a generated voltage for each of the diodes 122a and 122b between the diodes 122a and 122b and the duty converters 106a and 106b. The units 130a and 130b may be connected. Each hold unit 130a, 130b holds the voltage generated from each diode 122a, 122b by the holding control of the control unit 110, outputs the held voltage to the duty converters 106a, 106b, and also by the release control. Release the hold.

  While the hold units 130a and 130b hold and output the Ach generation voltage and the Bch generation voltage, the same voltage is converted into the duty signals AD and BD in the respective duty conversion units 106a and 106b, and the changeover switch 104. Will be output. Therefore, as shown in FIG. 4B, the control unit 110 outputs, for example, two sets of the Ach duty signal 201 and the Bch duty signal 202 to the microcomputer 114 via the photocoupler 112 in the same order. The changeover switch 104 is controlled as described above.

  Thereafter, the control unit 110 temporarily releases the holding of the holding units 130a and 130b, and holds new generated voltages from the diodes 122a and 122b by holding control again. Then, as shown in FIG. 4B, the selector switch 104 is configured so that two sets of the Ach duty signal 211 and the Bch duty signal 212 are output to the microcomputer 114 via the photocoupler 112, for example, two sets in the same order. To control. This control may be performed so that Ach and Bch are reversed as shown in FIG.

  By controlling in this way, the following effects can be obtained. In a device that handles high power, such as the inverter 30, there is a case where a data signal cannot be read accurately due to the influence of noise. In particular, the temperature information of the duty signal handled here changes when the waveform collapses due to noise.

  Therefore, as shown in FIG. 4 (b) or (c) described above, the same duty signal is transmitted at least twice, and the microcomputer 114 compares the read value (temperature value) of the two duty signals, The read value (temperature value) is adopted only when the difference between the two is within a predetermined reference value. Alternatively, when the same data signal is transmitted three times or more, only the reading values that occupy a large number of those reading values are validated. Further, when the same data signal is transmitted three times or more, reading values exceeding a predetermined reference value are excluded from the reading values, and the remaining reading values are validated.

  In this way, even if the voltage generated by the diodes 122a and 122b is affected by noise, the duty signal as a data signal affected by the noise is not adopted as temperature information by the microcomputer 114, and thus erroneous recognition occurs. Will disappear. Further, since only appropriate temperature information is adopted in the microcomputer 114, the temperature information can be accurately recognized.

  In the above description, the diodes 122a and 122b as temperature detection elements have two configurations. However, as shown in FIG. 6, the same effect can be obtained in the case of three configurations in which one diode 122c is added. I can do it. That is, in the case of the three configurations, the switching element 35c connected to the output side of the buffer 116 via the resistor Rc is associated with the Cch-side diode 122c as shown by a one-dot chain line frame 120c to form one package. The anode end of the Cch side diode 122b is connected to the Cch side duty converter 106c by wiring. Further, each duty converter 106a, 106b, 106c is connected to a three-input type changeover switch 104-1.

  However, in this configuration, each of the duty converters 106a to 106c performs PWM modulation so that the duty signals AD, BD, and CD have different duties. For example, the Ach-side duty converter 106a PWM modulates the Ach-side generated voltage to become an Ach duty signal AD with a duty of 0 to 33%, and the Bch-side duty converter 106b The PWM modulation is performed so that the duty signal BD of 34 to 66% Bch is obtained, and the Cch side duty converter 106c performs PWM modulation so that the generated voltage on the Cch side becomes the duty signal CD of Cch having a duty of 67 to 100%. .

  In the temperature detection circuit 100-2 having such a configuration, as shown in FIGS. 7A to 7C, the Ach duty signal AD, the Bch duty signal BD, and the Cch duty signal CD are AD, BD, and CD, AD, CD and BD, or CD, BD and AD are arranged in this order and output to the microcomputer 114 via the photocoupler 112.

(Second Embodiment)
FIG. 8 is a block diagram showing the configuration of the temperature detection circuit of the power conversion device according to the second embodiment of the present invention.

  The temperature detection circuit 100-3 illustrated in FIG. 8 includes a duty converter 106 that converts a plurality of generated voltages into duty signals having different duties, comparators (operational amplification means) 106a1 and 106b1 using operational amplifiers, and a non-inverting input of the comparator 106b1. A level shift unit 106j connected between the terminal “+” and the anode side of the Bch side diode 122b, and a reference wave generation unit 106k that generates a sawtooth wave J1 shown in FIG. 9B as a reference wave. The PWM modulation is used.

  The level shift unit 106j offsets (level shifts) the level of the generated voltage on the Bch side higher than the level of the generated voltage on the Ach side, as shown in FIG. 9B, and compares the comparators 106-1 and 106-2. Then, when the Ach and Bch duty signals AD and BD are generated by comparing the Ach side or Bch side level with the sawtooth wave J1, the duty of the Ach duty signal AD falls within the range of 0 to 49%. The duty signal BD is offset so that the duty is in the range of 51 to 100%.

  One comparator 106a1 has a non-inverting input terminal “+” connected to the anode side of the Ach side diode 122a, and an inverting input terminal “−” connected to the generation end of the sawtooth wave J1 of the reference wave generation unit 106b. One end is connected to one input end of the changeover switch 104.

  The other comparator 106b1 has a non-inverting input terminal “+” connected to the output terminal of the level shift unit 106j, an inverting input terminal “−” connected to the generation terminal of the sawtooth wave J1 of the reference wave generating unit 106b, and an output terminal. Is connected to the other input terminal of the changeover switch 104.

  In addition to generating the sawtooth wave J1, the reference wave generation unit 106k generates a pulsed peak signal P1 that rises long and narrow as shown in FIG. 9C at the falling edge of the sawtooth wave J1, and supplies this to the control unit 110. It is designed to output.

  The controller 110 outputs the switching control signal K1 shown in FIG. 9D to the changeover switch 104 with the peak signal P1 as a reference. That is, the peak signal P1 is generated by the apex (peak) of the sawtooth wave J1 at time t1, and the switching control signal K1 rises by this peak signal P1, and the changeover switch 104 selects the Ach duty signal AD accordingly. Switch to The sawtooth wave J1 falls instantaneously from the peak to “L”, and gradually rises to the right again and is supplied to the inverting input terminal “−” of the rise comparator 106a1. By supplying the sawtooth wave J1, the Ach duty signal AD from the comparator 106a1 becomes "H".

  When the level of the gradually rising sawtooth wave J1 exceeds the generated voltage level on the Ach side supplied to the non-inverting input terminal “+” of the comparator 106a1 at time t2, the Ach duty signal AD from the comparator 106a1. Falls from “H” to “L”.

  Further, when the level of the sawtooth wave J1 gradually increases and peaks at time t3, a peak signal P1 is generated, and the changeover switch 104 switches to the side for selecting the Bch duty signal BD by this peak signal P1. The sawtooth wave J1 falls instantaneously from the peak to “L”, and gradually rises to the right again and is supplied to the inverting input terminal “−” of the rise comparator 106b1. By supplying the sawtooth wave J1, the Bch duty signal BD from the comparator 106b1 becomes “H”.

  When the level of the gradually rising sawtooth wave J1 exceeds the generated voltage level on the Bch side supplied to the non-inverting input terminal “+” of the comparator 106b1 at time t4, the Bch duty signal BD from the comparator 106b1. Falls from “H” to “L”.

  Further, when the level of the sawtooth wave J1 gradually increases and peaks at time t5, a peak signal P1 is generated, and the changeover switch 104 is switched to the side for selecting the Ach duty signal AD by this peak signal P1. Thereafter, operations similar to those at times t1 to t5 are repeated.

  Next, calculation processing when the data signal DS shown in FIG. 9A is input to the microcomputer 114 via the photocoupler 112 will be described. The data signal DS is also shown in FIG.

  The microcomputer 114 includes a timer counter (not shown) and first and second registers. FIG. 10B shows the count value TC of the timer counter, FIG. 10C shows the first register value RT1 of the first register, and FIG. 10D shows the second register value RT2 of the second register.

  The timer counter resets the count value TC at the rising edge or falling edge of the data signal DS, and counts the “L” or “H” section of the data signal DS from zero. The first register acquires the count value TC at the falling edge of the data signal DS, and holds this as the first register value RT1. The second register acquires the count value TC at the rising edge of the data signal DS, and holds this as the second register value RT2.

  For example, when the Ach duty signal ad falls at time t1 in FIG. 10, “A1”, which is the count value TC of the “H” section of the Ach duty signal AD of the timer counter at this falling edge, is the first register value. The count value “A1” is reset after being held as RT1. The timer counter then counts the “L” section of the Ach duty signal AD. When the Bch duty signal BD rises at time t2, “A2” of the count value TC in the “L” section of the Ach duty signal AD is held as the second register value RT2 at this rising edge. TC is reset. The timer counter then counts the “H” section of the Bch duty signal BD.

  Next, when the Bch duty signal BD falls at time t3, the count value “B1” of the “H” section of the Bch duty signal BD is held as the first register value RT1 at this falling edge. The count value “B1” of the timer counter is reset. The timer counter then counts the “L” section of the Bch duty signal BD. When the Ach duty signal AD rises at time t4, the count value TC “B2” of the “L” section of the Bch duty signal BD is held as the second register value RT2 at this rising edge. The count value “B2” is reset. The timer counter then counts the “H” section of the Ach duty signal AD.

  Next, when the Ach duty signal AD falls at time t5, the count value “A1” of the “H” section of the Ach duty signal AD is held as the first register value RT1 at this falling edge. The count value “A1” of the timer counter is reset. Thereafter, the operations at times t1 to t5 are repeated.

  Further, the microcomputer 114 calculates each duty of the Ach duty signal AD and the Bch duty signal BD using the first and second register values RT1 and RT2 held in the first and second registers as described above. To do. The duty ADD of the Ach duty signal AD is calculated by A1 / (A1 + A2). The duty BDD of the Bch duty signal BD is calculated by B1 / (B1 + B2).

  As described above, the microcomputer 114 reads the first and second register values RT1 and RT2, and calculates the duty by interrupting at the falling edge or the rising edge of the duty signals AD and BD of the Ach and Bch. A method is also conceivable. With this method, the entire count value TC can be obtained with certainty, but the original processing of the microcomputer 114 may be delayed if interrupt processing is entered.

  Therefore, paying attention to the fact that the update of the first and second register values RT1, RT2 always takes longer than the basic period Dcy (see FIG. 10) of the duty signals AD, BD, the basic period Dcy is set to the main of the microcomputer 114. It was set longer than the loop time. By setting in this way, the microcomputer 114 reads the first and second register values RT1, RT2, and calculates the duty of the Ach and Bch duty signals AD, BD without interruption in the main loop. Can be done.

  Further, as shown in FIG. 11, in the case of three or more configurations in which one diode 122c is added, the duty converter 106-1 includes three comparators as indicated by reference numerals 106a1, 106b1, and 106c1, The level shift unit 106j1 may be connected between the non-inverting input terminal “+” of the comparators 106a1, 106b1, and 106c1 and the anode side of each of the diodes 122a to 122c.

  The level shift unit 106j1 offsets the generated voltages on the Ach side to Cch side to different levels and outputs the offset voltages to the non-inverting input terminals “+” of the comparators 106a1, 106b1, and 106c1, respectively. Accordingly, each of the comparators 106a1, 106b1, 106c1 compares the individual voltage offset by the level shift unit 106m with the sawtooth wave J1, and converts the individual voltage into duty signals AD, BD, CD having different duties. .

  As described above, in the power converter of the second embodiment, in the temperature detection circuit 100-3 or 100-4, the duty converter 106 generates the reference wave generator 106k that generates the sawtooth wave J1, the sawtooth wave J1, and each A plurality of comparators 106a1 and 106b1 that compare the generated voltages of the channel diodes 122a and 122b and convert the generated voltages into duty signals AD and BD, and offset one of the generated voltages to output to the comparators 106a1 and 106b1. And a level shift unit 106j. Then, by using the generated voltage offset by the level shift unit 106j in any of the comparators 106b1 for comparison with the sawtooth wave J1, the duty signals AD and BD converted by the comparators 106a1 and 106b1 have different duties. It was made to become.

  As a result, the voltages generated by the plurality of diodes 122a and 122b can be reliably determined, and after this determination, they can be converted into duty signals AD and BD having different duties, respectively.

  Further, since each of the comparators 106a1 and 106b1 performs duty conversion based on the sawtooth wave J1 that is one reference wave, this conversion operation is synchronized. Accordingly, when the duty signals AD and BD are alternately selected, for example, by the selector switch 104 at the subsequent stage of the comparators 106a1 and 106b1, the duty signals AD and BD can be alternately selected from the head at a predetermined cycle at the same timing. . Therefore, when the duty signals AD and BD are not synchronized, the selection positions of the duty signals AD and BD are different and the output waveform from the changeover switch 104 is not disturbed.

  Further, the reference wave generation unit 106k generates a pulsed peak signal P1 at the peak of the sawtooth wave J1, and the control unit 110 synchronizes with the peak signal P1, and each of the duty from each of the plurality of comparators 106a1 and 106b1. Selection control of different duty signals AD and BD is performed on the changeover switch 104.

  As a result, the selection operation of the changeover switch 104 that selects the duty signals with different duties output from the plurality of comparators 106a1 and 106b1 and outputs them to the microcomputer 114 is performed in synchronization with the constant peak signal P1 generated. The microcomputer 114 can properly acquire the duty signal. Further, since the duty signals AD and BD are selected in synchronism with the peak signal P1 that is generated constantly, it is possible to prevent erroneous selection.

  In addition to the temperature detection circuit 100-3 shown in FIG. 8, the duty conversion unit 106-3 includes a reference wave generation unit 106k and a temperature detection circuit 100-5 shown in FIG. And a plurality of comparators 106a1 and 106b1 and a level shift unit 106j2 (second level shift means) for offsetting the level of the sawtooth wave J1 generated by the reference wave generation unit 106k. Then, by using the sawtooth wave J1 offset by the level shift unit 106j2 for any of the comparators 106a1 for comparison with the voltage generated on the Ach side, the duty signals converted by the plurality of comparators 106a1 and 106b1 are different from each other. You may make it become a duty. As a result, the voltages generated by the plurality of diodes 122a and 122b can be reliably converted to the duty converters 106a and 106b having different duties.

  The microcomputer 114 also includes a timer counter that starts a count operation after resetting at the rising edge or falling edge of the duty signals AD and BD input from the changeover switch 104 via the signal transmission element, and the rising edge or falling edge. And a register for holding the count value TC of the timer counter as first and second register values RT1 and RT2 before the reset, and a duty signal using the first and second register values RT1 and RT2 held in the registers Arithmetic processing including calculation for obtaining the duty of AD and BD is performed. In the present embodiment, the period of the duty signals AD and BD is set longer than the period of the main loop of the microcomputer 114 that performs the arithmetic processing.

  Accordingly, since the cycle of the duty signals AD and BD is longer than the cycle of the main loop of the microcomputer 114, the microcomputer 114 reads the register value and calculates the duty of the duty signals AD and BD in the main loop. This can be done without interruption.

  Further, when the duty converters 106 to 106-3 convert the generated voltages of the plurality of channels into the duty signals AD and BD by pulse width modulation, the duty ratio of the duty signals AD and BD is less than 100%. Restrict.

  In this way, since there is always a rising edge or falling edge of the duty signals AD and BD, the microcomputer 114 can always identify the duty signals AD and BD.

(Third embodiment)
FIG. 13 is a block diagram showing a configuration of a temperature detection circuit of the power conversion device according to the third embodiment of the present invention.

  A temperature detection circuit 100-6 illustrated in FIG. 13 includes a duty converter 106-4 that converts a plurality of generated voltages into duty signals having different duties, comparators 106a1 and 106b1, and a non-inverting input terminal “+” of the comparator 106b1. PWM modulation is performed using a level shift unit 106j connected between the Bch side diode 122b and the anode side, and a reference wave generation unit 106m that generates a triangular wave J2 shown in FIG. 14B as a reference wave. It is configured.

  The level shift unit 106j offsets the level of the generated voltage on the Bch side to be lower than the level of the generated voltage on the Ach side as shown in FIG. Alternatively, when the Ach and Bch duty signals AD and BD are generated by comparing the Bch side level with the triangular wave J2, the duty of the Ach duty signal AD is in the range of 0 to 49%, and the Bch duty signal BD Offset is performed so that the duty is in the range of 51 to 100%.

  In addition to generating the triangular wave J2, the reference wave generating unit 106m rises at the lowest point (also referred to as the lower peak) and falls at the apex (also referred to as the upper peak) as shown in FIG. 14 (c). A rectangular peak signal (second peak signal) P <b> 2 is generated and output to the control unit 110.

  The control unit 110 outputs a switching control signal K2 shown in FIG. 14D to the changeover switch 104 based on the peak signal P2. In other words, the switching control signal K2 rises at the rising edge of the peak signal P2 at time t1, and the changeover switch 104 switches to the side for selecting the Ach duty signal AD in response to this, whereby the duty signal AD becomes a photo signal as the data signal DS1. The data is output to the microcomputer 114 via the coupler 112.

  Thereafter, the triangular wave J2 supplied to the inverting input terminal “−” of each of the comparators 106a1 and 106b1 gradually rises to the right from the time t1 and is supplied to the non-inverting input terminal “+” on the Ach side. When the level of the generated voltage is exceeded at time t2, the Ach duty signal AD output from the comparator 106a1 rises from "L" to "H".

  When the triangular wave J2 reaches an upper peak at time t3, the peak signal P2 falls. Further, when the triangular wave J2 falls from the upper peak and falls below the Ach side generated voltage at time t4, the Ach duty signal AD falls from “H” to “L”. Further, when the triangular wave J2 becomes a lower peak at time t5, the peak signal P2 rises, and thereafter, at time t5 to t9, an operation similar to that at times t1 to t4 is performed, so that the duty signal AD of a predetermined duty is selected by the changeover switch 104. Is done. That is, at time t1 to t9, two duty signals AD having the same duty are continuously output to the microcomputer 114.

  Next, the switching control signal K2 falls due to the falling edge of the peak signal P2 at time t9, and the changeover switch 104 switches to the side for selecting the Bch duty signal BD in response to this, whereby the duty signal BD becomes the data signal. DS1 is output to the microcomputer 114 via the photocoupler 112.

  After that, when the triangular wave J2 rises gradually from time t9 and rises upward and exceeds the level of the Bch-side generated voltage offset by the level shift unit 106j at time t10, the Bch output from the comparator 106b1 The duty signal BD rises from “L” to “H”.

  When the triangular wave J2 reaches an upper peak at time t11, the peak signal P2 falls. Further, when the triangular wave J2 falls from the upper peak and falls below the generated voltage on the Bch side after the offset at time t12, the Bch duty signal BD falls from “H” to “L”. Further, when the triangular wave J2 becomes a lower peak at time t13, the peak signal P2 rises, and thereafter, at time t13 to t17, the same operation as at time t9 to t13 is performed, so that the duty signal BD of a predetermined duty Bch is selected by the changeover switch 104. Is done. That is, two duty signals BD having the same duty are continuously output to the microcomputer 114 at times t9 to t17. Thereafter, operations similar to those at times t1 to t17 are repeated.

  The reason why the two duty signals AD or BD of the same channel are continued in this way is as follows. For example, at the switching timing from the Ach duty signal AD to the Bch duty signal BD at time t9, the switching is performed at the same “L” level, so the microcomputer 114 cannot determine the switching timing. In this case, since “L” of Ach or Bch cannot be accurately detected, the duty of Ach or Bch cannot be accurately detected.

  Therefore, as shown at times t9 to t17, if an “L” section between “H” and “H” of two consecutive Bch duty signals BD is detected and used for duty calculation, Bch can be accurately detected. Can be obtained. The same applies to the Ach side.

  As described above, in the power conversion device according to the third embodiment, in the temperature detection circuit 100-6, the reference wave generation unit 106m generates a triangular wave J2 that alternately repeats rising and falling with a constant slope as a reference wave, and the triangular wave J2 A second peak signal P2 that falls or rises at the apex or the lowest point is generated. The plurality of comparators 106a1 and 106b1 generate duty signals AD and BD having different duties by comparing the generated voltage of the plurality of diodes 122a and 122b including the generated voltage offset by the level shift unit 106j with the triangular wave J2. To do. Then, the control unit 110 causes at least two of the same duty signal AD or BD to be continuous based on the peak signal P2 among the duty signals AD and BD having different duties output from the comparators 106a1 and 106b1. In addition, the selection of the changeover switch 104 is controlled.

  As a result, the same effects as those of the first and second embodiments can be obtained. Further, since at least two or more of the same channels of the duty signal AD or BD are continuous, the same “L” or “H” level is continuous at the time of switching the channels of the duty signals AD and BD. Thus, it is possible to eliminate the fact that any data signal cannot be recognized and the microcomputer 114 cannot obtain an accurate duty. That is, if the duty signal AD of two identical channels (for example, Ach) is continuous, the “L” section between the “H” and “H” can be detected. At 114, the duty can be obtained.

  In addition, as in the temperature detection circuit 100-7 illustrated in FIG. 15, a hold unit 130a serving as a holding unit is provided between the diode 122a and the non-inverting input terminal “+” of the comparator 106a1, and the diode 122b and the level shift unit 106j. A hold unit 130b may be connected between the two.

  As shown in FIG. 16, the hold units 130a and 130b are controlled by the switching control signal K3 of the control unit 110, and when the switching control signal K3 is “H” for four periods of the peak signal P2, The generated voltage on the Ach side is held, and the held voltage is output to the duty converter 106a1. Further, when the switching control signal K3 is “L” for four periods of the peak signal P2, the generated voltage on the Bch side from the diode 122b is held, and the held voltage is supplied to the duty conversion unit via the level shift unit 106j. To 106b.

  By controlling in this way, the following effects can be obtained. In a device that handles high power, such as the inverter 30, there is a case where a data signal cannot be read accurately due to the influence of noise. In particular, the temperature information of the duty signal handled here changes when the waveform collapses due to noise.

  Therefore, the generated voltage on the Ach side or Bch side is held, and the same duty signal based on the held generated voltage is transmitted a plurality of times, and the read value (temperature value) of the plurality of duty signals is read by the microcomputer 114. In comparison, the read value (temperature value) is adopted only when the difference between the two is within a predetermined reference value. Alternatively, when the same data signal is transmitted three times or more, only the reading values that occupy a large number of those reading values are validated. Further, when the same data signal is transmitted three times or more, reading values exceeding a predetermined reference value are excluded from the reading values, and the remaining reading values are validated.

  In this way, even if the voltage generated by the diodes 122a and 122b is affected by noise, the duty signal as a data signal affected by the noise is not adopted as temperature information by the microcomputer 114, and thus erroneous recognition occurs. Will disappear. Further, since only appropriate temperature information is adopted in the microcomputer 114, the temperature information can be accurately recognized.

  Incidentally, as shown in FIG. 8, in the temperature detection circuit 100-3 of the second embodiment, the reference wave generation unit 106k generates the sawtooth wave J1, and the comparators 106a1 and 106b1 are offset by the level shift unit 106j. Duty signals AD and BD having different duties are generated by comparing the generated voltages of a plurality of channels including the generated voltage with the sawtooth wave J1. Then, the control unit 110 controls the changeover switch 104 so that duty signals AD and BD having different duties are alternately selected as shown in FIG.

  Therefore, in the case of the configuration of the temperature detection circuit 100-3 of the second embodiment, the duty signals AD and BD having different duties are alternately transmitted, so that the same duty signal is at least 2 using the triangular wave J2 of the third embodiment. The transmission can be speeded up as compared with a configuration where two or more are continuous.

(Fourth embodiment)
FIG. 17 is a block diagram showing a configuration of a temperature detection circuit of the power conversion device according to the fourth embodiment of the present invention.

  The temperature detection circuit 100-8 of the fourth embodiment shown in FIG. 17 is different from the temperature detection circuit 100-3 of the second embodiment shown in FIG. 2 in that the changeover switch 104 and the control unit 110 are eliminated, and duty conversion is performed. The part 106-5 is configured as follows. That is, the duty conversion unit 106-5 includes a level shift unit 106j, a two-input type changeover switch 105, a comparator 106ab, and a reference wave generation unit 106k that generates the sawtooth wave J1 and the peak signal P1. The anode of the diode 122a is connected to one input terminal of the changeover switch 105, the output terminal of the changeover switch 105 is connected to the non-inverting input terminal “+” of the comparator 106ab, and the anode of the Bch side diode 122b is switched. The other input terminal of the switch 105 was connected, and the output terminal of the comparator 106ab was connected to the photocoupler 112. Further, the sawtooth wave J1 of the reference wave generator 106k is supplied to the inverting input terminal “−” of the comparator 106ab, and the peak signal P1 is supplied to the control terminal of the changeover switch 105.

  According to such a configuration, the Ach side generated voltage or the Bch side generated voltage offset by the level shift unit 106j is selected by the changeover switch 105 that switches according to the peak signal P1. The selected Ach side or Bch side generated voltage is supplied to the non-inverting input terminal “+”, and at the time of the supply, the sawtooth wave J1 supplied to the inverting input terminal “−” causes the duty signals AD, Converted to BD. The converted duty signals AD and BD are output to the photocoupler 112.

  The effect similar to 2nd Embodiment can be acquired also by the temperature detection circuit 100-8 of the power converter device of such 4th Embodiment.

(Fifth embodiment)
FIG. 18 is a block diagram showing a configuration of a temperature detection circuit of the power conversion device according to the fifth embodiment of the present invention.

  The temperature detection circuit 100-9 according to the fourth embodiment shown in FIG. 18 is different from the temperature detection circuit 100-5 according to the application example of the second embodiment shown in FIG. The duty converter 106-6 is configured as follows. That is, the duty conversion unit 106-6 includes a level shift unit 106j2, a 4-input type 2-output type changeover switch 106, a comparator 106ab, and a reference wave generation unit 106k that generates the sawtooth wave J1 and the peak signal P1. It is prepared for. However, the changeover switch 106 includes a switching configuration of the first and second input ends and the first output end, and a switching configuration of the third and fourth input ends and the second output end.

  The anode of the Ach-side diode 122a is connected to the first input terminal of the changeover switch 106, the anode of the Bch-side diode 122b is connected to the second input terminal, and the first output terminal is connected to the non-inverting input terminal “+” of the comparator 106ab. Connected. The output terminal of the level shift unit 106j to which the sawtooth wave J1 from the reference wave generator 106k is supplied is connected to the third input terminal of the changeover switch 106, and the output terminal of the sawtooth wave J1 of the changeover switch 106 is the fourth input. The second output terminal is connected to the inverting input terminal “−” of the comparator 106ab. Further, the peak signal P1 of the reference wave generator 106k is supplied to the control terminal of the changeover switch 106.

  According to such a configuration, when the first input terminal of the changeover switch 106 is connected to the first output terminal and the third input terminal is connected to the second output terminal according to the peak signal P1, the comparator 106a. The generated voltage on the Ach side is supplied to the non-inverting input terminal “+”, and the sawtooth wave J1 offset to the inverting input terminal “−” is supplied. As a result, the voltage generated on the Ach side is converted into a duty signal AD having a predetermined duty and output to the photocoupler 112.

  Thereafter, when the next peak signal P1 is input to the changeover switch 106, the second input terminal is connected to the first output terminal, the fourth input terminal is connected to the second output terminal, and the non-inverting input terminal of the comparator 106a. The generated voltage on the Bch side is supplied to “+”, and the sawtooth wave J1 is supplied to the inverting input terminal “−”. As a result, the generated voltage on the Bch side is converted into a duty signal BD having a predetermined duty and output to the photocoupler 112. Thereafter, the Ach or Bch duty signals AD and BD are alternately output to the photocoupler 112 in this way.

  The effect similar to that of the application example of the second embodiment can also be obtained by the temperature detection circuit 100-9 of the power conversion device of the fifth embodiment.

  However, the detailed circuit of the reference wave generating unit 106k described above includes a power supply 126, constant current circuits 131a and 131b, a comparator 134, switches 135 and 136, a capacitor C1, and a resistor Rc as shown in FIG. , Rd, and Re. In this configuration, the comparator 134 detects the voltage of the capacitor C1 via the non-inverting input terminal “+”, and if the voltage is low, the constant current circuit 131a supplies current to the capacitor C1. As a result, the voltage gradually increases, and when this voltage reaches a predetermined value, the comparator 134 is turned on to generate the peak signal P1, and the switches 135 and 136 are turned on by the peak signal P1.

  As a result, the charge of the capacitor C1 is discharged by the constant current circuit 131b connected in series to the constant current circuit 131a and having a current drawn twice as large as that of the constant current circuit 131a, and the voltage value of the capacitor C1 rapidly decreases. When this voltage falls below a predetermined value, the peak signal P1 disappears, the switches 135 and 136 are turned off, and charging to the capacitor C1 is started again. Thereafter, the same process is repeated, and the sawtooth wave J1 is continuously generated. In addition, although the reference wave generation unit 106b that generates the sawtooth wave J1 is used in the temperature detection circuits 100-8 to 100-9, the reference wave generation unit 106m that generates the triangular wave J2 and the peak signal P2 may be used.

  In addition, in the temperature detection circuits 100 to 100-7 in the above-described embodiment, the duty converters 106 to 106-4 are configured so that the Ach side and Bch generated voltages are A / D (analog / digital) as shown in FIG. The converter 141 may convert the digital signal into a digital signal, and the duty signal may be obtained by reading the width of the digital signal with the counter value of the timer 142. Reading the width of the digital signal with the counter value by the timer 142 means, for example, that one period of the duty signal is “100”, the width of “H” of the digital signal is “10”, and the width of “L” is “ 90 ”and a duty signal with a duty“ 10 ”is obtained.

  Thus, in the configuration using the A / D converter 141 and the timer 142 in the duty converter, the duty change due to the voltage drop delay from the peak of the sawtooth wave J1 as in the temperature detection circuit 100-3 shown in FIG. You do not have to think about.

  For example, as shown in FIG. 21 (b), the fall from the peak of the sawtooth wave J1 in the temperature detection circuit 100-3 of the second embodiment causes a charge to a capacitor (not shown) for generating the sawtooth wave J1. Since the discharge is performed during charging / discharging, the discharge may take longer than necessary. For this reason, it may take from time t9 to time t9b when time has elapsed tdb more than necessary.

  Thus, when the discharge takes time, the slope of the falling edge of the sawtooth wave J1 becomes smooth. In the case of this smooth falling edge, the falling edge that actually falls below the Bch-side generated voltage at time t9 falls below the Bch-side generated voltage at time t9a delayed by time tda, and at this time, the header signal HdB to Bch To the duty signal BD. In this case, the duty of the Bch duty signal BD differs from the predetermined value by the delay time tda. If the duty is different in this way, there is a concern that the microcomputer 114 may recognize it as an incorrect value.

  However, in the configuration using the A / D converter 141 and the timer 142 in the above-described duty conversion unit, it is not necessary to consider the voltage drop time during discharge unlike the sawtooth wave J1, and therefore the duty does not change. Will not be mistakenly recognized.

DESCRIPTION OF SYMBOLS 10 Power converter 20 Converter 21, 22 Switching element 23 Capacitor 24 Reactor 30 Inverter 34-39 Switching element D1-D8 Diode MG Motor generator 100, 100-1 to 100-9 Temperature detection circuit 102 Switching circuit 104-106 Changeover switch 106 106-6 Duty conversion unit 110 Control unit 112 Photocoupler 114 Microcomputer 116 Buffer 35a, 35b Switching element 120a, 120b Package 122a, 122b Diode 124a, 124b, 131a, 131b Constant current circuit 126 Power supply Ra, Rb, Rc, Rd, Re resistor 130a, 130b Hold unit 106a, 134 Comparator 106b, 106c Reference wave generator P1, P2 Peak signal J1 sawtooth J2 triangular wave K1, K2, K3 switching control signal AD, BD duty signal DS~DS1 data signal 135 and 136 switch 141 A / D converter 142 timer C1 capacitor

Claims (11)

A converter having a plurality of semiconductor elements for boosting a DC voltage and an inverter having a plurality of semiconductor elements for converting the boosted voltage in the converter into an AC voltage; In a power conversion device having a plurality of temperature detection elements that are individually associated and generate a voltage corresponding to the temperature of each semiconductor element,
A plurality of duty conversion means connected individually to each voltage generation side of the plurality of temperature detection elements, and converting each generated voltage into a duty signal having a different duty by pulse width modulation;
Selecting means for selecting duty signals having different duties converted by the plurality of duty converting means;
Control means for controlling the selection means so that the selection means alternately select the duty signals having different duties;
Arithmetic control means connected to the output side of the selection means via a signal transmission element that transmits the duty signal selected by the selection means;
With
Between each of the plurality of temperature detection elements and the plurality of duty conversion means, connecting a holding means for individually holding the generated voltages of the plurality of temperature detection elements and outputting them to the duty conversion means,
The control means converts the generated voltages individually held by the holding means into two duty signals by the two duty conversion means, and alternately selects and arranges these two duty signals. Controlling the selection of the selection means such that the set of duty signals is repeated a plurality of times in the same order ,
The arithmetic control unit stores the characteristic variation of the temperature detection element, and corrects the temperature information detected from the duty signal input from the selection unit via the signal transmission element with the stored characteristic variation. Comparing a plurality of identical duty signals selected by the selection means, and adopting the duty signal for detecting the temperature information only when the difference between them is within a predetermined reference value. The power converter characterized by this. A converter having a plurality of semiconductor elements for boosting a DC voltage and an inverter having a plurality of semiconductor elements for converting the boosted voltage in the converter into an AC voltage; In a power conversion device having a plurality of temperature detection elements that are individually associated and generate a voltage corresponding to the temperature of each semiconductor element,
A plurality of duty conversion means connected individually to each voltage generation side of the plurality of temperature detection elements, and converting each generated voltage into a duty signal having a different duty by pulse width modulation;
Selecting means for selecting duty signals having different duties converted by the plurality of duty converting means;
Control means for controlling the selection means so that the selection means alternately select the duty signals having different duties;
Arithmetic control means connected to the output side of the selection means via a signal transmission element that transmits the duty signal selected by the selection means;
With
Between each of the plurality of temperature detection elements and the plurality of duty conversion means, connecting a holding means for individually holding the generated voltages of the plurality of temperature detection elements and outputting them to the duty conversion means,
The control means converts the generated voltages individually held by the holding means into two duty signals by the two duty conversion means, and alternately selects and arranges these two duty signals. Controlling the selection of the selection means such that the set of duty signals is repeated a plurality of times in the same order ,
The arithmetic control unit stores the characteristic variation of the temperature detection element, and corrects the temperature information detected from the duty signal input from the selection unit via the signal transmission element with the stored characteristic variation. A duty signal exceeding a predetermined reference value is excluded from duty signals in the same plurality of sets selected by the selection means, and a duty signal that is not excluded is used for detecting the temperature information. The power converter characterized by the above-mentioned. The duty conversion means compares a reference wave generation means for generating a reference wave that repeats rising and falling at a constant cycle, and a reference wave generated by the reference wave generation means and the generated voltages of the plurality of temperature detection elements. The power converter according to claim 1 , further comprising: a plurality of operational amplification units that convert the generated voltage into a duty signal. The duty conversion means further comprises level shift means for offsetting generated voltages of the plurality of temperature detection elements and outputting the offset to the plurality of operational amplification means,
By using the generated voltage offset by the level shift means in any of the plurality of operational amplification means for comparison with the reference wave, each duty signal converted by the multiple operational amplification means has a different duty. The power conversion device according to claim 3 , wherein: The duty conversion means further includes second level shift means for offsetting the level of the reference wave generated by the reference wave generation means,
Each of the plurality of operational amplification means uses the reference wave offset by the second level shift means for comparison with the generated voltage, whereby each duty signal converted by the plurality of operational amplification means The power converter according to claim 3 , wherein the duty is different. The reference wave generating means generates a peak signal at the peak of the reference wave;
The control means controls the selection means to select duty signals having different duties from the plurality of operational amplification means in synchronization with a peak signal generated by the reference wave generation means. The power converter according to claim 4 or 5 . The arithmetic control means includes a counter that starts a count operation after resetting at the rising edge or falling edge of the duty signal input from the selection means via the signal transmission element, and at the rising edge or the falling edge. A register that holds the count value of the counter as a register value before the reset, and performs an arithmetic process including an operation for obtaining the duty of the duty signal using the register value held in the register. The power converter according to any one of claims 3 to 6 , wherein the cycle of the duty signal is set to be longer than the cycle of the main loop of the arithmetic control means. Any of the plurality of duty conversion means limits the duty ratio of the duty signal to be less than 100% when converting the voltage generated by the plurality of temperature detection elements into a duty signal. power converter according to any one of claims 3-7. The reference wave generating means generates a triangular wave that alternately repeats rising and falling at a constant slope as the reference wave, and generates a second peak signal that falls or rises at the apex or lowest point of the triangular wave,
The plurality of operational amplifiers generate duty signals each having a different duty by comparing the generated voltage of the plurality of temperature detection elements including the generated voltage offset by the level shift unit with the triangular wave,
The control means is configured to select at least two identical duty signals based on the second peak signal among duty signals having different duties output from the plurality of operational amplification means. 5. The power converter according to claim 4 , wherein selection of means is controlled. The reference wave generating means generates a sawtooth wave that repeats rising and falling at a constant cycle as the reference wave,
The plurality of operational amplifiers generate duty signals having different duties by comparing the generated voltages of the plurality of temperature detection elements including the generated voltage offset by the level shift unit with the sawtooth wave,
10. The power conversion apparatus according to claim 4 , wherein the control unit controls the selection unit so that the selection unit alternately selects the duty signals having different duties. 11. The duty conversion means converts one of the voltages generated by the plurality of temperature detection elements into a digital signal instead of means for converting the voltage generated by the plurality of temperature detection elements into a duty signal having a predetermined duty by pulse width modulation. 3. The power conversion according to claim 1, further comprising: an analog / digital conversion unit that performs conversion; and a counter unit that converts the width of the converted digital signal into a duty signal having a predetermined duty. apparatus.

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