WO2017179095A1 - Power conversion device - Google Patents

Power conversion device Download PDF

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Publication number
WO2017179095A1
WO2017179095A1 PCT/JP2016/061687 JP2016061687W WO2017179095A1 WO 2017179095 A1 WO2017179095 A1 WO 2017179095A1 JP 2016061687 W JP2016061687 W JP 2016061687W WO 2017179095 A1 WO2017179095 A1 WO 2017179095A1
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WO
WIPO (PCT)
Prior art keywords
current
switching element
pulse width
switching elements
switching
Prior art date
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PCT/JP2016/061687
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French (fr)
Japanese (ja)
Inventor
田村　憲一
西尾　直樹
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2016/061687 priority Critical patent/WO2017179095A1/en
Priority to JP2018511552A priority patent/JP6570735B2/en
Publication of WO2017179095A1 publication Critical patent/WO2017179095A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode

Definitions

  • the present invention relates to a power converter for converting DC power into AC power.
  • the power converter performs power conversion by controlling the switching element with pulse width modulation (PWM).
  • PWM pulse width modulation
  • the switching element is mounted as a chip on a substrate in the power conversion device, the smaller the chip area, the higher the yield when taking out from the wafer, so the cost of the power conversion device can be reduced, but the chip area is reduced. As the current capacity decreases.
  • a technique is known in which power conversion is performed by controlling on / off of each of a plurality of switching elements connected in parallel with the same drive signal.
  • each of the plurality of switching elements connected in parallel has a characteristic difference such as an on threshold voltage, an on resistance, and a switching time. Furthermore, the current flowing through each of the plurality of switching elements connected in parallel has different values depending on the temperature. Therefore, when determining the current capacity of an inverter module composed of a plurality of switching elements, it is necessary to select each switching element in consideration of current imbalance in order not to exceed the current capacity of each switching element. is there. Therefore, the conventional power conversion device has a problem that the chip area is large and the cost merit by reducing the chip area is small.
  • Patent Document 1 the inductances of a plurality of signal lines for supplying a drive signal to each of a plurality of switching elements connected in parallel are made equal to each other, thereby turning on / off each of the plurality of switching elements connected in parallel.
  • a technique for suppressing current imbalance caused by different timings is disclosed.
  • Patent Document 1 since the actual power supply device and printed circuit board have a low degree of freedom due to wiring, it is difficult to make the inductances of the plurality of signal lines equal to each other. Further, when characteristics such as the ON threshold voltage, ON resistance, and switching time of the switching element change over time, the conventional technique disclosed in Patent Document 1 may not be able to correct the current imbalance. Therefore, the prior art of Patent Document 1 has a problem that it is difficult to achieve both cost reduction and large current.
  • the present invention has been made in view of the above, and an object of the present invention is to obtain a power conversion device that can achieve both reduction in cost and increase in current.
  • a power conversion device includes an inverter module in which a plurality of switching element pairs in which two switching elements are connected in series, and a switching element.
  • a control unit that generates a pulse width modulation signal to be controlled, and a current detection unit that detects a current flowing through the switching element, the control unit using each of the plurality of switching element pairs using the current detected by the current detection unit
  • a pulse width adjustment unit for adjusting the pulse width of the pulse width modulation signal for driving the signal.
  • the power conversion device according to the present invention has an effect that both cost reduction and large current can be achieved.
  • Configuration diagram of power conversion device according to Embodiment 1 The figure which shows an example of the PWM signal after the pulse width was adjusted in the control part shown in FIG.
  • Configuration diagram of power conversion device according to Embodiment 2
  • FIG. 1 is a configuration diagram of a power conversion device according to the first embodiment.
  • Power conversion apparatus 100 according to Embodiment 1 is connected to DC power supply 1 and commercial power supply system 8.
  • the DC power source 1 is a DC power supply means such as a solar cell module or a storage battery that supplies DC power to the power converter 100.
  • the power conversion device 100 has a function of converting DC power supplied from the DC power source 1 into AC power and outputting the AC power to the commercial power supply system 8, and serves as a power conditioner for photovoltaic power generation or a power conditioner for a storage battery. Used.
  • the power conversion apparatus 100 converts a DC voltage supplied from the DC power source 1 into a DC voltage having a desired value and outputs it, and a DC voltage output from the converter 50 having a desired value.
  • the inverter 51 which converts into an alternating voltage and outputs it, and the control part 18 are provided.
  • the control unit 18 includes a control circuit 9 that generates a PWM signal that is a pulse width modulation signal for controlling each of the inverter module 5, the inverter module 6, and the inverter module 7, and a drive circuit 39 that is a pulse width adjustment unit. Prepare. Details of the control circuit 9 and the drive circuit 39 will be described later.
  • the power conversion device 100 includes a reactor 11, a reactor 12, and a capacitor 10 that constitute a low-pass filter that attenuates a high-frequency component of the AC voltage output from the inverter 51.
  • the power conversion device 100 includes a relay 13 and a relay 14 that connect or disconnect the power conversion device 100 and the commercial power supply system 8.
  • the converter 50 is a general step-up chopper type DC-DC converter circuit.
  • the converter 50 has one end connected to the positive electrode of the DC power supply 1 and the other end connected to the negative electrode of the DC power supply 1, and one end connected to the capacitor 2.
  • a connected reactor 3 and an inverter module 5 connected to the other end of the reactor 3 are provided.
  • the inverter module 5 is used as a switching device in the converter 50.
  • the inverter module 5 includes a plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f.
  • a set of three switching elements connected in parallel is defined as an arm
  • a parallel connection circuit of the switching elements 5a, 5c, and 5e is referred to as an upper arm
  • the parallel connection of the switching elements 5b, 5d, and 5f is called the lower arm.
  • the plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f are connected in parallel, The current capacity can be increased.
  • the switching element 5a and the switching element 5b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
  • switching element 5c and switching element 5d constitute a switching element pair
  • switching element 5e and switching element 5f constitute a switching element pair
  • one end of each of these switching element pairs is connected to positive side DC bus 19a.
  • the other end of the switching element pair is connected to the negative-side DC bus 19b.
  • the converter 50 detects a current flowing through each of the plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f and outputs a plurality of currents corresponding to the current to the drive circuit 39 of the control unit 18. Detectors 21, 22, 23, 30, 31, 32 are provided. Converter 50 also detects capacitor 4 having one end connected to positive-side DC bus 19a and the other end connected to negative-side DC bus 19b, and detects the output voltage of converter 50 and controls a voltage signal corresponding to the output voltage. And a voltage detection unit 15 that outputs to the control circuit 9 of the unit 18.
  • the inverter 51 includes an inverter module 6 and an inverter module 7 that are used as switching devices in the inverter 51.
  • the inverter module 6 includes a plurality of switching elements 6 a, 6 b, 6 c, 6 d, 6 e, and 6 f in the same manner as the inverter module 5.
  • a parallel connection circuit of the switching elements 6a, 6c, and 6e is referred to as an upper arm, and a parallel connection circuit of the switching elements 6b, 6d, and 6f is referred to as a lower arm.
  • the plurality of switching elements are connected in parallel, The current capacity can be increased.
  • the switching element 6a and the switching element 6b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
  • switching element 6c and switching element 6d constitute a switching element pair
  • switching element 6e and switching element 6f constitute a switching element pair
  • one end of each of these switching element pairs is connected to positive side DC bus 19a.
  • the other end of the switching element pair is connected to the negative-side DC bus 19b.
  • the inverter module 7 includes a plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f, similarly to the inverter modules 5 and 6.
  • a parallel connection circuit of the switching elements 7a, 7c, and 7e is referred to as an upper arm, and a parallel connection circuit of the switching elements 7b, 7d, and 7f is referred to as a lower arm.
  • the plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f are small, the plurality of switching elements are connected in parallel, The current capacity can be increased.
  • the switching element 7a and the switching element 7b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
  • switching element 7c and switching element 7d constitute a switching element pair
  • switching element 7e and switching element 7f constitute a switching element pair
  • one end of each of these switching element pairs is connected to positive side DC bus 19a.
  • the other end of the switching element pair is connected to the negative-side DC bus 19b.
  • the inverter 51 detects a current flowing through each of the plurality of switching elements 6 a, 6 b, 6 c, 6 d, 6 e, 6 f and sends a current signal corresponding to the current to the drive circuit 39 of the control unit 18.
  • a plurality of current detectors 24, 25, 26, 33, 34, and 35 for outputting are provided.
  • the inverter 51 detects a current flowing through each of the plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f and outputs a plurality of currents corresponding to the current to the drive circuit 39 of the control unit 18. Detectors 27, 28, 29, 36, 37, and 38 are provided.
  • the output side of the inverter 51 is provided with a current detection unit 17 that detects the output current of the inverter 51 and outputs a current signal corresponding to the output current to the control circuit 9.
  • the output side of the inverter 51 is provided with a voltage detector 16 that detects the output voltage of the inverter 51 and outputs a voltage signal corresponding to the output voltage to the control circuit 9.
  • the control circuit 9 controls the inverter modules 5, 6, 7. ON / OFF operations of a plurality of switching elements constituting each of the above are controlled. Thereby, power conversion is performed in the power conversion device 100.
  • the control circuit 9 includes a parallel connection circuit that constitutes an upper arm of each of the inverter modules 5, 6, and 7, and a parallel connection circuit that constitutes a lower arm of each of the inverter modules 5, 6, and 7. These are regarded as one switching element having a large current capacity, and a PWM signal for driving these parallel connection circuits is generated.
  • the drive circuit 39 Based on the PWM signal generated by the control circuit 9, the drive circuit 39 generates a PWM signal, which is a drive signal, for PWM driving a plurality of switching elements constituting each of the inverter modules 5, 6, and 7. Specifically, the drive circuit 39 replicates three of each of the PWM signal of the parallel connection circuit that constitutes the upper arm and the PWM signal of the parallel connection circuit that constitutes the lower arm, and outputs the duplicated signal to the inverter module 5. , 6 and 7 are output.
  • the drive circuit 39 when the drive circuit 39 suppresses an imbalance of the current flowing through each of the inverter modules 5, 6, and 7, the drive circuit 39 performs a pulse width adjustment described later on the duplicated signal, The signal is output to each of the inverter modules 5, 6, and 7.
  • any element may be used, but GaN (gallium nitride) called a wide band gap semiconductor, SiC (silicon carbide) which is silicon carbide, or diamond can be used.
  • GaN gallium nitride
  • SiC silicon carbide
  • the withstand voltage is high and the allowable current density is also high, so that the module can be miniaturized.
  • the wide band gap semiconductor has high heat resistance, it is possible to reduce the size of the radiating fin of the radiating portion.
  • the switching element is mounted as a chip, the yield at the time of taking out from the wafer is improved by reducing the chip area.
  • SiC silicon carbide
  • the inverter in which the three switching elements are connected in parallel The current capacity of the module is ideally 3 ⁇ Am.
  • the drive circuit 39 has a function of generating individual PWM signals for PWM driving the switching elements 6 a, 6 b, 6 c, 6 d, 6 e, 6 f based on the PWM signal generated by the control circuit 9.
  • the control circuit 9 may have a function of generating individual PWM signals.
  • a drive circuit having a function of generating individual PWM signals may be provided in each of the inverter modules 5, 6, and 7.
  • the current detection unit 21 To 38 are input to the corresponding inverter modules 5, 6, and 7, or the current detection units 21 to 38 are provided inside the corresponding inverter modules 5, 6, and 7.
  • the three switching elements constituting the same arm each perform the same operation. Accordingly, the currents flowing through the three switching elements that constitute the same arm are substantially the same. However, in reality, even if three switching elements constituting the same arm perform the same operation due to a difference in various conditions including temperature, a difference occurs in the current flowing through each of the three switching elements. That is, an imbalance occurs in the current flowing through each of the three switching elements constituting the same arm.
  • the on-resistance decreases and the current flows more easily when the current increases and the temperature increases. If this occurs, the temperature of the element through which a large amount of current flows increases, and a larger amount of current flows.
  • a switching element having a negative temperature characteristic such as an IGBT (Insulated Gate Bipolar Transistor) formed of Si in addition to the switching element formed of SiC.
  • IGBT Insulated Gate Bipolar Transistor
  • the current capacity of the entire inverter module is set to a value obtained by subtracting a certain margin from the ideal 3 ⁇ Am described above. Must be set.
  • the margin value is small. Therefore, in this embodiment, in order to suppress current imbalance, the current of the switching element is detected and the pulse width is controlled based on the current. Even when a switching element that does not have a negative temperature characteristic is used, the pulse width may be controlled based on the current of the switching element as in this embodiment.
  • the drive circuit 39 narrows the pulse width of the PWM signal of the switching element having a large current value flowing through each of the switching elements 6b, 6d, and 6f, that is, a current value detected by the current detection units 24, 25, and 26.
  • the current value flowing through the switching elements 6b, 6d, 6f is lowered.
  • the drive circuit 39 increases the value of the current flowing through the switching elements 6b, 6d, and 6f by widening the pulse width of the PWM signal of the switching element having a small current value detected by the current detection units 24, 25, and 26.
  • a specific method for adjusting the pulse width of the PWM signal is to reduce the pulse width of the PWM signal of the switching element having a relatively large current value among the current values flowing through the switching elements 6b, 6d, and 6f.
  • any method may be used, but two examples are given below.
  • the first example is a method of adjusting the pulse widths of the detection results of the current detection units 24, 25, and 26, that is, the largest and smallest of the current values flowing through the switching elements 6b, 6d, and 6f, respectively. It is.
  • the drive circuit 39 obtains a current difference ⁇ I between the largest and smallest of the detection results of the current detection units 24, 25, and 26.
  • the current difference ⁇ I is an absolute value of the difference between the current values.
  • the drive circuit 39 obtains an increase / decrease amount p ⁇ of the pulse width corresponding to 1 ⁇ 2 of the obtained current difference ⁇ I.
  • the drive circuit 39 may hold the relationship between the pulse width and the current in advance, and use this relationship to obtain the increase / decrease amount p ⁇ of the pulse width corresponding to 1 ⁇ 2 of the current difference ⁇ I.
  • the drive circuit 39 may store the current difference ⁇ I and the increase / decrease amount p ⁇ of the pulse width as a table, and obtain the increase / decrease amount p ⁇ of the pulse width by referring to the table.
  • the drive circuit 39 duplicates the PWM signal output from the control circuit 9 to generate three PWM signals, and uses the increase / decrease amount p ⁇ of the pulse widths of the three PWM signals to switch the switching elements 6b, 6d, 6f. Increase or decrease the value of current flowing through each.
  • FIG. 2 is a diagram showing an example of a PWM signal after the pulse width is adjusted in the control unit shown in FIG.
  • the solid line represents the waveform of the PWM signal after being adjusted by the drive circuit 39
  • the dotted line represents the pulse width p0 of the PWM signal before being adjusted by the drive circuit 39.
  • P ⁇ is an increase / decrease amount of the pulse width corresponding to 1/2 of the current difference ⁇ I.
  • p0 is the PWM signal for driving each of the switching elements 6b, 6d, 6f before the increase / decrease of the pulse width, that is, the pulse width of the PWM signal output from the control circuit 9.
  • the current value that flows through the switching element 6b is the largest among the switching elements 6b, 6d, and 6f
  • the current value that flows through the switching element 6d is the next largest current value
  • the current value that flows through the switching element 6f is The smallest shall be assumed. That is, among the detection results of the current detection units 24, 25, and 26, the detection result of the current detection unit 24 is the largest, the detection result of the current detection unit 25 is the next largest, and the detection result of the current detection unit 26 is the smallest. To do.
  • the drive circuit 39 obtains a current difference ⁇ I between the detection result of the current detection unit 24 and the detection result of the current detection unit 26. Then, the drive circuit 39 obtains an increase / decrease amount p ⁇ of the pulse width corresponding to the current difference ⁇ I, widens the pulse width of the PWM signal for the switching element 6f by the increase / decrease amount ⁇ , and increases / decreases the pulse width of the PWM signal for the switching element 6b. Narrow by p ⁇ .
  • the pulse width increase / decrease amount p ⁇ has an upper limit value from the viewpoint of preventing arm short-circuiting, and is set to be equal to or less than the pause time width of each of the upper arm and lower arm PWM signals.
  • the pulse width of the PWM signal is adjusted according to the detection results of the current detectors 24, 25, and 26, that is, the amount of deviation from the average value of the current flowing through each of the switching elements 6b, 6d, and 6f. It is a method to do.
  • the drive circuit 39 obtains the average value of the current flowing through each of the current detection units 24, 25, and 26 and the current difference ⁇ I of each switching element.
  • the drive circuit 39 obtains the increase / decrease amount of the pulse width corresponding to the obtained current difference ⁇ I, and with respect to the PWM signal obtained by duplicating the PWM signal output from the control circuit 9 in the same manner as in the first example,
  • the pulse width of each PWM signal for each switching element is increased or decreased.
  • the amount of increase / decrease in the pulse width is set to an upper limit value from the viewpoint of preventing an arm short circuit, and is set to be equal to or less than the pause time width of the PWM signals of the upper arm and the lower arm.
  • the method for increasing / decreasing the pulse width described above is an example. Besides the above example, the current value flowing through each switching element is not used, but the current value flowing through each switching element is used instead of the current difference ⁇ I.
  • the threshold value is exceeded, the pulse width of the PWM signal for the switching element in which the current exceeding the threshold flows among the switching elements constituting the upper arm or the lower arm is reduced by a certain value, A method of increasing the pulse width of the PWM signal for the switching element by a certain value may be used.
  • the control circuit 9 performs power conversion by switching the switching elements 6a, 6b, 6c, 6d, 6e, and 6f between an on state and an off state at a constant period. In addition, the control circuit 9 adjusts the power by changing the ON / OFF time width of the switching elements 6a, 6b, 6c, 6d, 6e, and 6f in a state where the period is fixed.
  • the cycle of one cycle between the ON state and the OFF state of the switching elements 6a, 6b, 6c, 6d, 6e, and 6f is called a carrier cycle, and the ON / OFF time width is changed with the carrier cycle fixed.
  • the control is called PWM control.
  • the drive circuit 39 performs the pulse width adjustment described above at regular intervals. This fixed time may be a carrier cycle or may be longer than the carrier cycle. For example, the control may be performed such that the pulse width is adjusted for 10 seconds every minute and the pulse width is not adjusted for the remaining 50 seconds.
  • the drive circuit 39 provided outside the inverter module 6 adjusts the pulse width, that is, increases or decreases the pulse width.
  • the pulse width is adjusted inside the inverter module 6. May be.
  • signals indicating detection results of the current detection units 24, 25, and 26 are input to the inverter module 6.
  • a signal indicating the switching element having the largest current value may be output to the outside, or a signal indicating the current difference ⁇ between the current values of the switching elements having the largest current value may be output to the outside.
  • the pulse width of the PWM signal is increased / decreased at the timing when the PWM signal is switched from on to off.
  • the same effect can be achieved even when the PWM signal is switched from off to on. can get.
  • the method for adjusting the pulse width of the PWM signal for each of the switching elements 6a, 6c, 6e constituting the upper arm is the same as the method for adjusting the pulse width of the PWM signal for each of the switching elements 6b, 6d, 6f constituting the lower arm. It is.
  • the method for adjusting the pulse width of the inverter module 5 and the inverter module 7 is the same as the method for adjusting the pulse width of the inverter module 6.
  • current detection units 21 to 38 are provided in association with each of a plurality of switching elements constituting the inverter module, and detect currents flowing through each of the plurality of switching elements. Configured as follows. With this configuration, as a protection when an overcurrent flows through the switching element, when at least one of the currents detected by the current detection units 21 to 38 exceeds an allowable value, the drive circuit 39 performs all switching. The operation of the power conversion device 100 may be stopped by outputting an off signal to the element. As a result, the operation of the power conversion device 100 can be stopped based on the current detection result with a fast response speed. Therefore, the power conversion device 100 can be stopped quickly when an abnormality occurs, and the switching element can be prevented from being destroyed. Further, smoke and ignition of the power conversion device 100 can be prevented.
  • the current detection unit 17 detects the output current of the inverter 51 without using the current detection units 21 to 38 and detects that the current is an overcurrent and stops the protection
  • the current detection unit 17 After the current detection result is once transmitted to the control circuit 9 and the control circuit 9 determines an overcurrent, an operation of transmitting an off signal to the drive circuit 39 is required. Therefore, it takes several hundreds of seconds to stop the protection.
  • the overcurrent is detected by the current detectors 21 to 38, and the result of the overcurrent is transmitted directly to the drive circuit 39 without passing through the control circuit 9, and the drive circuit 39 is switched.
  • the time required to stop the protection is only a few u seconds.
  • the overcurrent protection operation when the overcurrent protection operation is performed using the current detection units 21 to 38, the operation can be stopped based on the current detection with a fast response speed, so that the operation can be quickly stopped at the time of abnormality, and the element is destroyed. Can be prevented.
  • the drive circuit 39 of the power conversion apparatus 100 adjusts the pulse width at regular intervals. As a result, it is possible to correct the current unbalance due to the temperature change over time or the current unbalance due to the characteristic change due to the secular change.
  • the power conversion device includes a switching element pair in which two switching elements are connected in series, and a plurality of inverter modules connected in parallel for each phase. For this reason, it is possible to realize a large current at a reduced cost.
  • the power conversion device detects the current flowing through the switching element, estimates the characteristic difference between the switching elements, and adjusts the pulse width of the PWM signal that is the drive signal, thereby imbalances the current. Configured to suppress. Thereby, when determining the current capacity as the inverter module, it is not necessary to consider the current unbalance, and the current capacity of each switching element can be used effectively.
  • one inverter module is configured by three pairs of switching elements.
  • the example is not limited to the example of FIG. 1, and one inverter module is configured by two or more pairs of switching elements. May be.
  • Embodiment 2 a power converter according to Embodiment 2 will be described.
  • a current detection unit that detects a current is provided for each switching element.
  • a current detection unit is provided for each arm of each inverter module.
  • FIG. 3 is a configuration diagram of the power conversion device according to the second embodiment.
  • FIG. 3 illustrates only a part of functions constituting the power conversion device 100-2 according to the second embodiment.
  • the difference from the first embodiment is that a power conversion device 100-2 according to the second embodiment includes a current detection unit 40 instead of the current detection units 24, 25, and 26 of the first embodiment. 1 is provided with a current detection unit 41 instead of the current detection units 33, 34, and 35, and a drive circuit 39 a is provided instead of the drive circuit 39.
  • Other components are the same as those in the first embodiment.
  • the current detection unit 40 detects a current at the junction of the connection lines of the switching elements 6b, 6d, and 6f on the lower arm of the inverter module 6.
  • the current detection unit 41 detects a current at the junction of the connection lines of the switching elements 6a, 6c, and 6e of the upper arm of the inverter module 6.
  • the inverter module 5 includes a current detection unit that detects current at the junction of the connecting lines of the lower arm switching elements 5b, 5d, and 5f, and the upper arm switching elements 5a, 5c, and 5e.
  • a current detection unit that detects current at a junction of the connection lines.
  • the inverter module 7 includes a current detection unit that detects current at the junction of the connecting lines of the lower arm switching elements 7b, 7d, and 7f, and the upper arm switching elements 7a, 7c, and 7e.
  • a current detection unit that detects current at a junction of the connection lines.
  • the current detection unit 40 can individually detect the current that flows through each of the switching elements 6b, 6d, and 6f.
  • the switching elements 6b, 6d are made to flow by changing the combination of opening and closing of the switching elements 6b, 6d, 6f while the power converter 100-2 is not normally operated. , 6f, that is, variation in on-resistance.
  • the drive circuit 39a controls to turn on the switching element 6b and turn off the switching elements 6d and 6f. In this state, the drive circuit 39a acquires and stores the current value detected by the current detection unit 40, that is, the current value flowing through the switching element 6b.
  • the drive circuit 39a turns on the switching element 6d and turns off the switching elements 6b and 6f, acquires and holds the current value flowing through the switching element 6d, turns on the switching element 6f, and turns on the switching element 6b. , 6d are turned off, and the current flowing through the switching element 6f is acquired and held. By detecting these currents, the drive circuit 39a can determine the ratio of the on resistances of the switching elements 6b, 6d, and 6f, that is, the variation in the characteristics of the switching elements 6b, 6d, and 6f. The drive circuit 39a calculates and holds the on-resistance ratios R6b, R6d, and R6f of the switching elements 6b, 6d, and 6f.
  • the drive circuit 39a also changes the combination of opening and closing of the switching elements 6a, 6c, and 6e for the switching elements 6a, 6c, and 6e of the upper arm, and allows the current to flow to change the switching elements 6a, 6c, and 6e.
  • the on-resistance ratios R6a, R6c, and R6e are calculated and held. Similarly, for the inverter modules 5 and 7, the ratio of the on-resistance of the switching element can be obtained for each arm.
  • the drive circuit 39a of the inverter module 6 is based on the current detected by the current detection unit of the upper arm and the on-resistance ratios R6a, R6c, and R6e that are held.
  • the current flowing through each of the switching elements 6a, 6c, 6e, that is, the shunt current is calculated.
  • the drive circuit 39a duplicates the upper arm PWM signal Up output from the control circuit 9 into three, and based on the calculated currents flowing through the switching elements 6a, 6c, and 6e, the pulse widths of the three signals.
  • the PWM signal after adjusting the pulse width is output to the corresponding switching element.
  • the method for adjusting the pulse width based on the current flowing through each of the switching elements 6a, 6c, 6e is the same as in the first embodiment.
  • the drive circuit 39a of the inverter module 6 includes switching elements 6b, 6d, and 6d based on the current detected by the current detection unit 40 of the lower arm and the on-resistance ratios R6b, R6d, and R6f that are held. The current flowing through each of 6f, that is, the shunt current is calculated. Then, the drive circuit 39a of the inverter module 6 duplicates the lower arm PWM signal Un output from the control circuit 9 into three, and based on the calculated currents flowing through the switching elements 6b, 6d, and 6f, The pulse width of the signal is adjusted, and the PWM signal after the pulse width adjustment is output to the corresponding switching element.
  • the method for adjusting the pulse width based on the current flowing through each of the switching elements 6b, 6d, 6f is the same as in the first embodiment.
  • the inverter modules 5 and 7 perform the duplication of the PWM signal input from the control circuit 9 and the adjustment of the pulse width according to the current for each arm, similarly to the inverter module 6.
  • the ratio of the on-resistance is calculated by changing the combination of opening and closing of the switching elements and flowing the current in a period in which the power conversion device is not normally operated.
  • the on-resistance ratio may be measured in advance, and the on-resistance ratio may be held as a table.
  • the temperature equivalent to the temperature of each switching element may be detected inside or outside the inverter module, and the ratio of the on-resistance for each switching element may be obtained based on the temperature detection result.
  • both the upper arm and the lower arm are provided with a current detection unit for each arm.
  • the upper arm is provided with a current detection unit for each arm, and the lower arm is described in the first embodiment.
  • the current detection unit is provided for each switching element, or the lower arm includes the current detection unit for each arm, and the upper arm includes the current detection unit for each switching element as described in the first embodiment.
  • the first embodiment and this embodiment may be combined.
  • the pulse may be adjusted according to a difference in switching timing that causes other current imbalance. For example, when the threshold voltage of the element varies, a difference occurs in the switching timing. Therefore, the element whose threshold voltage is low first when turning on is turned on first, and the element whose threshold voltage is high when turning off is finally turned off. Current concentrates on.
  • the difference in switching timing can be determined by detecting the current value after a lapse of a certain time from the rise of the drive signal, and the same effect as the example of calculating the on-resistance ratio by adjusting the pulse based on this can be obtained. it can.
  • current detection unit 40 and current detection unit 41 are provided in association with the upper arm and the lower arm constituting the inverter module, and flow to the upper arm and the lower arm. It is configured to detect current.
  • the pulse width of the PWM signal output to the switching element is adjusted based on the current detected for each arm and the ratio of the on-resistance between the switching elements in the same arm. Therefore, current imbalance can be suppressed as in the first embodiment, the number of current detection units can be reduced as compared with the first embodiment, and cost and size can be reduced.
  • the configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

Abstract

A power conversion device 100 is provided with: inverter modules 5, 6, 7, each of which has a plurality of switching element pairs that are connected in parallel, each of said switching element pairs having two switching elements connected in series; a control unit 18 that generates pulse width modulation signals for controlling the switching elements; and a current detection unit that detects currents flowing in the switching elements. The control unit 18 is provided with a drive circuit 39, i.e., a pulse width adjusting unit that adjusts, using the currents detected by the current detection unit, the pulse widths of the pulse width modulation signals for driving the switching element pairs, respectively.

Description

電力変換装置Power converter
　この発明は直流電力を交流電力に変換する電力変換装置に関する。 The present invention relates to a power converter for converting DC power into AC power.
　電力変換装置は、スイッチング素子をパルス幅変調（Ｐｕｌｓｅ　Ｗｉｄｔｈ　Ｍｏｄｕｌａｔｉｏｎ：ＰＷＭ）制御することにより電力変換を行う。電力変換装置内の基板に、スイッチング素子をチップとして実装する場合、チップ面積を小さくするほど、ウェハから取り出す際の歩留りが向上するため、電力変換装置のコストを低減できるが、チップ面積を小さくするほど電流容量が低下する。低コスト化と大電流化とを両立させるため、並列に接続された複数のスイッチング素子の各々を同一の駆動信号でオンオフ制御して電力変換を行う技術が知られている。 The power converter performs power conversion by controlling the switching element with pulse width modulation (PWM). When the switching element is mounted as a chip on a substrate in the power conversion device, the smaller the chip area, the higher the yield when taking out from the wafer, so the cost of the power conversion device can be reduced, but the chip area is reduced. As the current capacity decreases. In order to achieve both reduction in cost and increase in current, a technique is known in which power conversion is performed by controlling on / off of each of a plurality of switching elements connected in parallel with the same drive signal.
　しかしながら、並列に接続された複数のスイッチング素子の各々には、オンしきい値電圧、オン抵抗およびスイッチング時間といった特性の差異がある。さらに並列に接続された複数のスイッチング素子の各々に流れる電流は温度によって異なる値となる。従って複数のスイッチング素子で構成されたインバータモジュールの電流容量を決定する際、各スイッチング素子の電流容量を超えないようにするため、電流のアンバランス分を考慮して各スイッチング素子を選定する必要がある。従って従来の電力変換装置ではチップ面積が大きくなり、チップ面積を縮小することによるコストメリットが小さくなるという課題があった。 However, each of the plurality of switching elements connected in parallel has a characteristic difference such as an on threshold voltage, an on resistance, and a switching time. Furthermore, the current flowing through each of the plurality of switching elements connected in parallel has different values depending on the temperature. Therefore, when determining the current capacity of an inverter module composed of a plurality of switching elements, it is necessary to select each switching element in consideration of current imbalance in order not to exceed the current capacity of each switching element. is there. Therefore, the conventional power conversion device has a problem that the chip area is large and the cost merit by reducing the chip area is small.
　特許文献１には、並列に接続された複数のスイッチング素子の各々に駆動信号を与える複数の信号線のインダクタンスを互いに等しい値にすることによって、並列に接続された複数のスイッチング素子の各々のオンオフのタイミングが異なることに起因して生じる電流のアンバランスを抑制する技術が開示されている。 In Patent Document 1, the inductances of a plurality of signal lines for supplying a drive signal to each of a plurality of switching elements connected in parallel are made equal to each other, thereby turning on / off each of the plurality of switching elements connected in parallel. A technique for suppressing current imbalance caused by different timings is disclosed.
特許第５５５９２６５号公報Japanese Patent No. 5559265
　しかしながら、実際の電源装置およびプリント基板は、配線の引き回しによる自由度が低いため、複数の信号線のインダクタンスを互いに等しい値にすることは困難である。またスイッチング素子のオンしきい値電圧、オン抵抗およびスイッチング時間といった特性が経年変化した場合、特許文献１に開示される従来技術では電流のアンバランスを補正できない場合がある。従って特許文献１の従来技術は低コスト化と大電流化とを両立させることが困難という課題があった。 However, since the actual power supply device and printed circuit board have a low degree of freedom due to wiring, it is difficult to make the inductances of the plurality of signal lines equal to each other. Further, when characteristics such as the ON threshold voltage, ON resistance, and switching time of the switching element change over time, the conventional technique disclosed in Patent Document 1 may not be able to correct the current imbalance. Therefore, the prior art of Patent Document 1 has a problem that it is difficult to achieve both cost reduction and large current.
　本発明は、上記に鑑みてなされたものであって、低コスト化と大電流化を両立させることができる電力変換装置を得ることを目的とする。 The present invention has been made in view of the above, and an object of the present invention is to obtain a power conversion device that can achieve both reduction in cost and increase in current.
　上述した課題を解決し、目的を達成するために、本発明に係る電力変換装置は、２つのスイッチング素子が直列に接続されたスイッチング素子対が複数並列に接続されたインバータモジュールと、スイッチング素子を制御するパルス幅変調信号を生成する制御部と、スイッチング素子に流れる電流を検出する電流検出部とを備え、制御部は、電流検出部が検出した電流を用いて、複数のスイッチング素子対の各々を駆動するためのパルス幅変調信号のパルス幅を調整するパルス幅調整部を備える。 In order to solve the above-described problems and achieve the object, a power conversion device according to the present invention includes an inverter module in which a plurality of switching element pairs in which two switching elements are connected in series, and a switching element. A control unit that generates a pulse width modulation signal to be controlled, and a current detection unit that detects a current flowing through the switching element, the control unit using each of the plurality of switching element pairs using the current detected by the current detection unit A pulse width adjustment unit for adjusting the pulse width of the pulse width modulation signal for driving the signal.
　本発明に係る電力変換装置は、低コスト化と大電流化を両立させることができるという効果を奏する。 The power conversion device according to the present invention has an effect that both cost reduction and large current can be achieved.
実施の形態１に係る電力変換装置の構成図Configuration diagram of power conversion device according to Embodiment 1 図１に示す制御部においてパルス幅が調整された後のＰＷＭ信号の一例を示す図The figure which shows an example of the PWM signal after the pulse width was adjusted in the control part shown in FIG. 実施の形態２に係る電力変換装置の構成図Configuration diagram of power conversion device according to Embodiment 2
　以下に、本発明の実施の形態に係る電力変換装置を図面に基づいて詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。 Hereinafter, a power converter according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
実施の形態１．
　図１は実施の形態１に係る電力変換装置の構成図である。実施の形態１に係る電力変換装置１００は直流電源１および商用電源系統８に接続される。直流電源１は、電力変換装置１００に直流電力を供給する太陽電池モジュールまたは蓄電池といった直流電力供給手段である。電力変換装置１００は、直流電源１から供給される直流電力を交流電力に変換して商用電源系統８に出力する機能を有し、太陽光発電用のパワーコンディショナまたは蓄電池用のパワーコンディショナとして用いられる。 Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a power conversion device according to the first embodiment. Power conversion apparatus 100 according to Embodiment 1 is connected to DC power supply 1 and commercial power supply system 8. The DC power source 1 is a DC power supply means such as a solar cell module or a storage battery that supplies DC power to the power converter 100. The power conversion device 100 has a function of converting DC power supplied from the DC power source 1 into AC power and outputting the AC power to the commercial power supply system 8, and serves as a power conditioner for photovoltaic power generation or a power conditioner for a storage battery. Used.
　具体的には、電力変換装置１００は、直流電源１から供給される直流電圧を所望の値の直流電圧に変換して出力するコンバータ５０と、コンバータ５０が出力される直流電圧を所望の値の交流電圧に変換して出力するインバータ５１と、制御部１８とを備える。制御部１８は、インバータモジュール５、インバータモジュール６およびインバータモジュール７の各々を制御するためのパルス幅変調信号であるＰＷＭ信号を生成する制御回路９と、パルス幅調整部である駆動回路３９とを備える。制御回路９および駆動回路３９の詳細は後述する。 Specifically, the power conversion apparatus 100 converts a DC voltage supplied from the DC power source 1 into a DC voltage having a desired value and outputs it, and a DC voltage output from the converter 50 having a desired value. The inverter 51 which converts into an alternating voltage and outputs it, and the control part 18 are provided. The control unit 18 includes a control circuit 9 that generates a PWM signal that is a pulse width modulation signal for controlling each of the inverter module 5, the inverter module 6, and the inverter module 7, and a drive circuit 39 that is a pulse width adjustment unit. Prepare. Details of the control circuit 9 and the drive circuit 39 will be described later.
　また電力変換装置１００は、インバータ５１から出力される交流電圧の高周波成分を減衰させるローパスフィルタを構成するリアクトル１１、リアクトル１２、およびコンデンサ１０を備える。また電力変換装置１００は、電力変換装置１００と商用電源系統８とを接続しまたは接続を解除するリレー１３およびリレー１４を備える。 Further, the power conversion device 100 includes a reactor 11, a reactor 12, and a capacitor 10 that constitute a low-pass filter that attenuates a high-frequency component of the AC voltage output from the inverter 51. The power conversion device 100 includes a relay 13 and a relay 14 that connect or disconnect the power conversion device 100 and the commercial power supply system 8.
　コンバータ５０は、一般的な昇圧チョッパ型の直流－直流変換回路であり、一端が直流電源１の正極に接続され他端が直流電源１の負極に接続されたコンデンサ２と、一端がコンデンサ２に接続されたリアクトル３と、リアクトル３の他端に接続されたインバータモジュール５とを備える。 The converter 50 is a general step-up chopper type DC-DC converter circuit. The converter 50 has one end connected to the positive electrode of the DC power supply 1 and the other end connected to the negative electrode of the DC power supply 1, and one end connected to the capacitor 2. A connected reactor 3 and an inverter module 5 connected to the other end of the reactor 3 are provided.
　インバータモジュール５は、コンバータ５０におけるスイッチングデバイスとして用いられる。インバータモジュール５は、複数のスイッチング素子５ａ，５ｂ，５ｃ，５ｄ，５ｅ，５ｆを備える。本実施の形態では、並列に接続された３つのスイッチング素子の組をアームと定義し、スイッチング素子５ａ，５ｃ，５ｅの並列接続回路を上アームと称し、スイッチング素子５ｂ，５ｄ，５ｆの並列接続回路を下アームと称する。本実施の形態に係る電力変換装置１００では、複数のスイッチング素子５ａ，５ｂ，５ｃ，５ｄ，５ｅ，５ｆの各々の電流容量が小さい場合でも、複数のスイッチング素子が並列に接続されることにより、電流容量を大きくできる。 The inverter module 5 is used as a switching device in the converter 50. The inverter module 5 includes a plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f. In the present embodiment, a set of three switching elements connected in parallel is defined as an arm, a parallel connection circuit of the switching elements 5a, 5c, and 5e is referred to as an upper arm, and the parallel connection of the switching elements 5b, 5d, and 5f. The circuit is called the lower arm. In the power conversion device 100 according to the present embodiment, even when the current capacities of the plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f are small, the plurality of switching elements are connected in parallel, The current capacity can be increased.
　スイッチング素子５ａおよびスイッチング素子５ｂは、直列に接続されたスイッチング素子対を構成し、当該スイッチング素子対の一端は正極側直流母線１９ａに接続され、当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 The switching element 5a and the switching element 5b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
　同様に、スイッチング素子５ｃおよびスイッチング素子５ｄはスイッチング素子対を構成し、スイッチング素子５ｅおよびスイッチング素子５ｆはスイッチング素子対を構成し、これらのスイッチング素子対の各々の一端は正極側直流母線１９ａに接続され、これらの当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 Similarly, switching element 5c and switching element 5d constitute a switching element pair, switching element 5e and switching element 5f constitute a switching element pair, and one end of each of these switching element pairs is connected to positive side DC bus 19a. The other end of the switching element pair is connected to the negative-side DC bus 19b.
　またコンバータ５０は、複数のスイッチング素子５ａ，５ｂ，５ｃ，５ｄ，５ｅ，５ｆの各々に流れる電流を検出して当該電流に相当する電流信号を制御部１８の駆動回路３９に出力する複数の電流検出部２１，２２，２３，３０，３１，３２を備える。またコンバータ５０は、一端が正極側直流母線１９ａに接続され他端が負極側直流母線１９ｂに接続されるコンデンサ４と、コンバータ５０の出力電圧を検出して当該出力電圧に相当する電圧信号を制御部１８の制御回路９に出力する電圧検出部１５とを備える。 The converter 50 detects a current flowing through each of the plurality of switching elements 5a, 5b, 5c, 5d, 5e, and 5f and outputs a plurality of currents corresponding to the current to the drive circuit 39 of the control unit 18. Detectors 21, 22, 23, 30, 31, 32 are provided. Converter 50 also detects capacitor 4 having one end connected to positive-side DC bus 19a and the other end connected to negative-side DC bus 19b, and detects the output voltage of converter 50 and controls a voltage signal corresponding to the output voltage. And a voltage detection unit 15 that outputs to the control circuit 9 of the unit 18.
　インバータ５１は、インバータ５１におけるスイッチングデバイスとして用いられるインバータモジュール６およびインバータモジュール７を備える。 The inverter 51 includes an inverter module 6 and an inverter module 7 that are used as switching devices in the inverter 51.
　インバータモジュール６は、インバータモジュール５と同様に、複数のスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆを備える。スイッチング素子６ａ，６ｃ，６ｅの並列接続回路を上アームと称し、スイッチング素子６ｂ，６ｄ，６ｆの並列接続回路を下アームと称する。本実施の形態に係る電力変換装置１００では、複数のスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆの各々の電流容量が小さい場合でも、複数のスイッチング素子が並列に接続されることにより、電流容量を大きくできる。 The inverter module 6 includes a plurality of switching elements 6 a, 6 b, 6 c, 6 d, 6 e, and 6 f in the same manner as the inverter module 5. A parallel connection circuit of the switching elements 6a, 6c, and 6e is referred to as an upper arm, and a parallel connection circuit of the switching elements 6b, 6d, and 6f is referred to as a lower arm. In the power conversion device 100 according to the present embodiment, even when the current capacities of the plurality of switching elements 6a, 6b, 6c, 6d, 6e, and 6f are small, the plurality of switching elements are connected in parallel, The current capacity can be increased.
　スイッチング素子６ａおよびスイッチング素子６ｂは、直列に接続されたスイッチング素子対を構成し、当該スイッチング素子対の一端は正極側直流母線１９ａに接続され、当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 The switching element 6a and the switching element 6b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
　同様に、スイッチング素子６ｃおよびスイッチング素子６ｄはスイッチング素子対を構成し、スイッチング素子６ｅおよびスイッチング素子６ｆはスイッチング素子対を構成し、これらのスイッチング素子対の各々の一端は正極側直流母線１９ａに接続され、これらの当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 Similarly, switching element 6c and switching element 6d constitute a switching element pair, switching element 6e and switching element 6f constitute a switching element pair, and one end of each of these switching element pairs is connected to positive side DC bus 19a. The other end of the switching element pair is connected to the negative-side DC bus 19b.
　インバータモジュール７は、インバータモジュール５，６と同様に、複数のスイッチング素子７ａ，７ｂ，７ｃ，７ｄ，７ｅ，７ｆを備える。スイッチング素子７ａ，７ｃ，７ｅの並列接続回路を上アームと称し、スイッチング素子７ｂ，７ｄ，７ｆの並列接続回路を下アームと称する。本実施の形態に係る電力変換装置１００では、複数のスイッチング素子７ａ，７ｂ，７ｃ，７ｄ，７ｅ，７ｆの各々の電流容量が小さい場合でも、複数のスイッチング素子が並列に接続されることにより、電流容量を大きくできる。 The inverter module 7 includes a plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f, similarly to the inverter modules 5 and 6. A parallel connection circuit of the switching elements 7a, 7c, and 7e is referred to as an upper arm, and a parallel connection circuit of the switching elements 7b, 7d, and 7f is referred to as a lower arm. In the power conversion device 100 according to the present embodiment, even when the current capacities of the plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f are small, the plurality of switching elements are connected in parallel, The current capacity can be increased.
　スイッチング素子７ａおよびスイッチング素子７ｂは、直列に接続されたスイッチング素子対を構成し、当該スイッチング素子対の一端は正極側直流母線１９ａに接続され、当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 The switching element 7a and the switching element 7b constitute a switching element pair connected in series, one end of the switching element pair is connected to the positive side DC bus 19a, and the other end of the switching element pair is the negative side DC bus 19b. Connected to.
　同様に、スイッチング素子７ｃおよびスイッチング素子７ｄはスイッチング素子対を構成し、スイッチング素子７ｅおよびスイッチング素子７ｆはスイッチング素子対を構成し、これらのスイッチング素子対の各々の一端は正極側直流母線１９ａに接続され、これらの当該スイッチング素子対の他端は負極側直流母線１９ｂに接続される。 Similarly, switching element 7c and switching element 7d constitute a switching element pair, switching element 7e and switching element 7f constitute a switching element pair, and one end of each of these switching element pairs is connected to positive side DC bus 19a. The other end of the switching element pair is connected to the negative-side DC bus 19b.
　インバータ５１は、コンバータ５０と同様に、複数のスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆの各々に流れる電流を検出して当該電流に相当する電流信号を制御部１８の駆動回路３９に出力する複数の電流検出部２４，２５，２６，３３，３４，３５を備える。またインバータ５１は、複数のスイッチング素子７ａ，７ｂ，７ｃ，７ｄ，７ｅ，７ｆの各々に流れる電流を検出して当該電流に相当する電流信号を制御部１８の駆動回路３９に出力する複数の電流検出部２７，２８，２９，３６，３７，３８を備える。 Similarly to the converter 50, the inverter 51 detects a current flowing through each of the plurality of switching elements 6 a, 6 b, 6 c, 6 d, 6 e, 6 f and sends a current signal corresponding to the current to the drive circuit 39 of the control unit 18. A plurality of current detectors 24, 25, 26, 33, 34, and 35 for outputting are provided. The inverter 51 detects a current flowing through each of the plurality of switching elements 7a, 7b, 7c, 7d, 7e, and 7f and outputs a plurality of currents corresponding to the current to the drive circuit 39 of the control unit 18. Detectors 27, 28, 29, 36, 37, and 38 are provided.
　インバータ５１の出力側には、インバータ５１の出力電流を検出して当該出力電流に相当する電流信号を制御回路９に出力する電流検出部１７が設けられている。またインバータ５１の出力側には、インバータ５１の出力電圧を検出して当該出力電圧に相当する電圧信号を制御回路９に出力する電圧検出部１６が設けられている。 The output side of the inverter 51 is provided with a current detection unit 17 that detects the output current of the inverter 51 and outputs a current signal corresponding to the output current to the control circuit 9. The output side of the inverter 51 is provided with a voltage detector 16 that detects the output voltage of the inverter 51 and outputs a voltage signal corresponding to the output voltage to the control circuit 9.
　以下では、インバータモジュール６を構成する複数のスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆを制御する例を説明し、インバータモジュール５，７に関しては、インバータモジュール６と同様に制御されるものとしてその説明を割愛する。 Below, the example which controls the some switching element 6a, 6b, 6c, 6d, 6e, 6f which comprises the inverter module 6 is demonstrated, and the inverter modules 5 and 7 are controlled similarly to the inverter module 6 I will omit that explanation.
　制御回路９は、電圧検出部１５で検出された電圧値と、電圧検出部１６で検出された電圧値と、電流検出部１７で検出された電流値とに基づき、インバータモジュール５，６，７の各々を構成する複数のスイッチング素子のオンオフ動作を制御する。これにより電力変換装置１００では電力変換が行われる。具体的には、制御回路９は、インバータモジュール５，６，７のそれぞれの上アームを構成する並列接続回路と、インバータモジュール５，６，７のそれぞれの下アームを構成する並列接続回路とを、それぞれ電流容量の大きな一つのスイッチング素子であるとみなし、これらの並列接続回路を駆動するためのＰＷＭ信号を生成する。 Based on the voltage value detected by the voltage detector 15, the voltage value detected by the voltage detector 16, and the current value detected by the current detector 17, the control circuit 9 controls the inverter modules 5, 6, 7. ON / OFF operations of a plurality of switching elements constituting each of the above are controlled. Thereby, power conversion is performed in the power conversion device 100. Specifically, the control circuit 9 includes a parallel connection circuit that constitutes an upper arm of each of the inverter modules 5, 6, and 7, and a parallel connection circuit that constitutes a lower arm of each of the inverter modules 5, 6, and 7. These are regarded as one switching element having a large current capacity, and a PWM signal for driving these parallel connection circuits is generated.
　駆動回路３９は、制御回路９により生成されたＰＷＭ信号に基づいて、インバータモジュール５，６，７の各々を構成する複数のスイッチング素子をＰＷＭ駆動するため駆動信号であるＰＷＭ信号を生成する。具体的には、駆動回路３９は、上アームを構成する並列接続回路のＰＷＭ信号と、下アームを構成する並列接続回路のＰＷＭ信号とを各々３つ複製し、複製した信号を、インバータモジュール５，６，７の各々に出力する。 Based on the PWM signal generated by the control circuit 9, the drive circuit 39 generates a PWM signal, which is a drive signal, for PWM driving a plurality of switching elements constituting each of the inverter modules 5, 6, and 7. Specifically, the drive circuit 39 replicates three of each of the PWM signal of the parallel connection circuit that constitutes the upper arm and the PWM signal of the parallel connection circuit that constitutes the lower arm, and outputs the duplicated signal to the inverter module 5. , 6 and 7 are output.
　また駆動回路３９は、インバータモジュール５，６，７の各々の内部に流れる電流のアンバランスを抑制する場合、複製した信号に対して、後述するパルス幅の調整を行い、パルス幅の調整後の信号をインバータモジュール５，６，７の各々へ出力する。 In addition, when the drive circuit 39 suppresses an imbalance of the current flowing through each of the inverter modules 5, 6, and 7, the drive circuit 39 performs a pulse width adjustment described later on the duplicated signal, The signal is output to each of the inverter modules 5, 6, and 7.
　スイッチング素子としては、どのような素子を用いてもよいが、ワイドバンドギャップ半導体と呼ばれるＧａＮ（窒化ガリウム）、炭化珪素であるＳｉＣ（シリコンカーバイド）、またはダイヤモンドを用いることができる。ワイドバンドギャップ半導体を用いることで耐電圧性が高く、許容電流密度も高くなるため、モジュールの小型化が可能となる。ワイドバンドギャップ半導体は、耐熱性も高いため、放熱部の放熱フィンの小型化も可能になる。スイッチング素子をチップとして実装する場合、チップ面積を小さくすると、ウェハから取り出す際の歩留りが向上する。特に、スイッチング素子としてＳｉＣを用いる場合、ウェハが高価であることから、低コスト化のためにはチップ面積を小さくすることが望ましい。 As the switching element, any element may be used, but GaN (gallium nitride) called a wide band gap semiconductor, SiC (silicon carbide) which is silicon carbide, or diamond can be used. By using a wide band gap semiconductor, the withstand voltage is high and the allowable current density is also high, so that the module can be miniaturized. Since the wide band gap semiconductor has high heat resistance, it is possible to reduce the size of the radiating fin of the radiating portion. When the switching element is mounted as a chip, the yield at the time of taking out from the wafer is improved by reducing the chip area. In particular, when SiC is used as the switching element, since the wafer is expensive, it is desirable to reduce the chip area for cost reduction.
　チップ面積を小さくすると電流容量が小さくなるが、電流容量が小さい複数のスイッチング素子を並列に接続することにより、低コスト化と大電流化とを両立できる。 When the chip area is reduced, the current capacity is reduced. However, by connecting a plurality of switching elements having a small current capacity in parallel, both cost reduction and large current can be achieved.
　本実施の形態のように、上アームのスイッチング素子および下アームのスイッチング素子をそれぞれ３並列で構成し、各スイッチング素子の電流容量をＡｍとしたとき、３つのスイッチング素子が並列に接続されたインバータモジュールの電流容量は、理想的には３×Ａｍとなる。 As in the present embodiment, when the switching element of the upper arm and the switching element of the lower arm are respectively configured in parallel, and the current capacity of each switching element is Am, the inverter in which the three switching elements are connected in parallel The current capacity of the module is ideally 3 × Am.
　なお図１では、制御回路９により生成されたＰＷＭ信号に基づいてスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆをＰＷＭ駆動するための個別のＰＷＭ信号を生成する機能を、駆動回路３９が有する例を示す。しかしながら、制御回路９が個別のＰＷＭ信号を生成する機能を有していてもよい。また、インバータモジュール５，６，７のそれぞれの内部に、個別のＰＷＭ信号を生成する機能を有した駆動回路を設けてもよい。 In FIG. 1, the drive circuit 39 has a function of generating individual PWM signals for PWM driving the switching elements 6 a, 6 b, 6 c, 6 d, 6 e, 6 f based on the PWM signal generated by the control circuit 9. The example which has is shown. However, the control circuit 9 may have a function of generating individual PWM signals. Further, a drive circuit having a function of generating individual PWM signals may be provided in each of the inverter modules 5, 6, and 7.
　なおインバータモジュール５，６，７のそれぞれの内部に、個別のＰＷＭ信号を生成する機能を有した駆動回路を設けて、電流のアンバランスを抑制するパルス幅の調整を行う場合、電流検出部２１から３８で検出された電流値が、対応するインバータモジュール５，６，７へ入力され、または電流検出部２１から３８が、対応するインバータモジュール５，６，７の内部に設けられる。インバータモジュール５，６，７の内部に駆動回路を設けることにより、基板面積を低減できる。 When a drive circuit having a function of generating individual PWM signals is provided in each of the inverter modules 5, 6, and 7 to adjust the pulse width to suppress current imbalance, the current detection unit 21 To 38 are input to the corresponding inverter modules 5, 6, and 7, or the current detection units 21 to 38 are provided inside the corresponding inverter modules 5, 6, and 7. By providing a drive circuit inside the inverter modules 5, 6 and 7, the substrate area can be reduced.
　本実施の形態では、同一のアームを構成する３つのスイッチング素子は各々が同様の動作を行う。従って、同一のアームを構成する３つのスイッチング素子に流れる電流は、概略同じである。しかしながら、実際には温度を含む諸条件の差異により、同一のアームを構成する３つのスイッチング素子が同一の動作を行っていたとしても、３つのスイッチング素子のそれぞれに流れる電流には差異が生じる。すなわち、同一のアームを構成する３つのスイッチング素子のそれぞれに流れる電流にアンバランスが生じる。 In the present embodiment, the three switching elements constituting the same arm each perform the same operation. Accordingly, the currents flowing through the three switching elements that constitute the same arm are substantially the same. However, in reality, even if three switching elements constituting the same arm perform the same operation due to a difference in various conditions including temperature, a difference occurs in the current flowing through each of the three switching elements. That is, an imbalance occurs in the current flowing through each of the three switching elements constituting the same arm.
　特にＳｉＣにより形成されたスイッチング素子のように、電流が流れて温度が上昇するとオン抵抗が低下しさらに電流が流れやすくなる特性、すなわち温度負特性を有するスイッチング素子を使用する場合、電流のアンバランスが生じると、電流が多く流れている素子の温度が上昇し、さらにより多くの電流が流れることになってしまう。ＳｉＣにより形成されたスイッチング素子以外にも、Ｓｉで形成されたＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）といった温度負特性を有するスイッチング素子を用いる場合も同様である。電流のアンバランスが生じた場合でも各スイッチング素子が電流容量を超えないようにするためには、インバータモジュール全体の電流容量を、上述した理想的な３×Ａｍから一定のマージンを減じた値として設定する必要がある。しかしながら、インバータモジュールの電流容量を大きくするためには、上記のマージンの値は小さい方が望ましい。このため本実施の形態では、電流のアンバランスを抑制するために、スイッチング素子の電流を検出し、電流に基づいてパルス幅を制御する。なお、温度負特性を有しないスイッチング素子を用いる場合においても、本実施の形態のようなスイッチング素子の電流に基づくパルス幅の制御を行ってもよい。 In particular, when using a switching element having a negative temperature characteristic, such as a switching element formed of SiC, the on-resistance decreases and the current flows more easily when the current increases and the temperature increases. If this occurs, the temperature of the element through which a large amount of current flows increases, and a larger amount of current flows. The same applies to a switching element having a negative temperature characteristic such as an IGBT (Insulated Gate Bipolar Transistor) formed of Si in addition to the switching element formed of SiC. In order to prevent each switching element from exceeding the current capacity even when current imbalance occurs, the current capacity of the entire inverter module is set to a value obtained by subtracting a certain margin from the ideal 3 × Am described above. Must be set. However, in order to increase the current capacity of the inverter module, it is desirable that the margin value is small. Therefore, in this embodiment, in order to suppress current imbalance, the current of the switching element is detected and the pulse width is controlled based on the current. Even when a switching element that does not have a negative temperature characteristic is used, the pulse width may be controlled based on the current of the switching element as in this embodiment.
　次にパルス幅の調整例として、インバータモジュール６の下アームを構成するスイッチング素子６ｂ，６ｄ，６ｆのパルス幅の調整について説明する。 Next, adjustment of the pulse width of the switching elements 6b, 6d, and 6f constituting the lower arm of the inverter module 6 will be described as an example of adjusting the pulse width.
　駆動回路３９は、スイッチング素子６ｂ，６ｄ，６ｆのそれぞれに流れる電流値、すなわち電流検出部２４，２５，２６で検出された電流値が大きいスイッチング素子のＰＷＭ信号のパルス幅を狭くすることによって、スイッチング素子６ｂ，６ｄ，６ｆに流れる電流値を下げる。また駆動回路３９は、電流検出部２４，２５，２６で検出された電流値が小さいスイッチング素子のＰＷＭ信号のパルス幅を広くすることによってスイッチング素子６ｂ，６ｄ，６ｆに流れる電流値を上げる。 The drive circuit 39 narrows the pulse width of the PWM signal of the switching element having a large current value flowing through each of the switching elements 6b, 6d, and 6f, that is, a current value detected by the current detection units 24, 25, and 26. The current value flowing through the switching elements 6b, 6d, 6f is lowered. Further, the drive circuit 39 increases the value of the current flowing through the switching elements 6b, 6d, and 6f by widening the pulse width of the PWM signal of the switching element having a small current value detected by the current detection units 24, 25, and 26.
　ＰＷＭ信号のパルス幅の具体的な調整方法は、スイッチング素子６ｂ，６ｄ，６ｆのそれぞれに流れる電流値の内、電流値が相対的に大きいスイッチング素子のＰＷＭ信号のパルス幅を狭くし、電流値が相対的に小さいスイッチング素子のＰＷＭ信号のパルス幅を広くできれば、どのような方法で行ってもよいが、以下に例を２つ挙げる。 A specific method for adjusting the pulse width of the PWM signal is to reduce the pulse width of the PWM signal of the switching element having a relatively large current value among the current values flowing through the switching elements 6b, 6d, and 6f. As long as the pulse width of the PWM signal of the switching element having a relatively small value can be increased, any method may be used, but two examples are given below.
　一例目は、電流検出部２４，２５，２６の検出結果、すなわちスイッチング素子６ｂ，６ｄ，６ｆのそれぞれに流れる電流値の内、最も大きいものと最も小さいものとの各々のパルス幅を調整する方法である。 The first example is a method of adjusting the pulse widths of the detection results of the current detection units 24, 25, and 26, that is, the largest and smallest of the current values flowing through the switching elements 6b, 6d, and 6f, respectively. It is.
　駆動回路３９は、電流検出部２４，２５，２６のそれぞれの検出結果の内、最も大きいものと最も小さいものとの電流差ΔＩを求める。なお電流差ΔＩは電流値の差の絶対値とする。そして駆動回路３９は、求めた電流差ΔＩの１／２に相当するパルス幅の増減量ｐαを求める。駆動回路３９は、パルス幅と電流との関係を予め保持しておき、この関係を用いて、電流差ΔＩの１／２に相当するパルス幅の増減量ｐαを求めてもよい。また駆動回路３９は、電流差ΔＩとパルス幅の増減量ｐαとを対応付けたテーブルとして保持しておき、テーブルを参照してパルス幅の増減量ｐαを求めてもよい。 The drive circuit 39 obtains a current difference ΔI between the largest and smallest of the detection results of the current detection units 24, 25, and 26. Note that the current difference ΔI is an absolute value of the difference between the current values. Then, the drive circuit 39 obtains an increase / decrease amount pα of the pulse width corresponding to ½ of the obtained current difference ΔI. The drive circuit 39 may hold the relationship between the pulse width and the current in advance, and use this relationship to obtain the increase / decrease amount pα of the pulse width corresponding to ½ of the current difference ΔI. Alternatively, the drive circuit 39 may store the current difference ΔI and the increase / decrease amount pα of the pulse width as a table, and obtain the increase / decrease amount pα of the pulse width by referring to the table.
　そして駆動回路３９は、制御回路９から出力されたＰＷＭ信号を複製して３つのＰＷＭ信号を生成し、３つのＰＷＭ信号のパルス幅の増減量ｐαを用いて、スイッチング素子６ｂ，６ｄ，６ｆのそれぞれに流れる電流値を増減させる。 Then, the drive circuit 39 duplicates the PWM signal output from the control circuit 9 to generate three PWM signals, and uses the increase / decrease amount pα of the pulse widths of the three PWM signals to switch the switching elements 6b, 6d, 6f. Increase or decrease the value of current flowing through each.
　図２は図１に示す制御部においてパルス幅が調整された後のＰＷＭ信号の一例を示す図である。実線は駆動回路３９で調整された後のＰＷＭ信号の波形を表し、点線は駆動回路３９で調整される前のＰＷＭ信号のパルス幅ｐ０を表す。Ｐαは電流差ΔＩの１／２に相当するパルス幅の増減量である。ｐ０は、パルス幅の増減前のスイッチング素子６ｂ，６ｄ，６ｆのそれぞれを駆動するためのＰＷＭ信号、すなわち制御回路９から出力されたＰＷＭ信号のパルス幅である。 FIG. 2 is a diagram showing an example of a PWM signal after the pulse width is adjusted in the control unit shown in FIG. The solid line represents the waveform of the PWM signal after being adjusted by the drive circuit 39, and the dotted line represents the pulse width p0 of the PWM signal before being adjusted by the drive circuit 39. Pα is an increase / decrease amount of the pulse width corresponding to 1/2 of the current difference ΔI. p0 is the PWM signal for driving each of the switching elements 6b, 6d, 6f before the increase / decrease of the pulse width, that is, the pulse width of the PWM signal output from the control circuit 9.
　図２の例では、スイッチング素子６ｂ，６ｄ，６ｆの内、スイッチング素子６ｂに流れる電流値が最も大きく、スイッチング素子６ｄに流れる電流値が次に電流値が大きく、スイッチング素子６ｆに流れる電流値が最も小さいものとする。すなわち電流検出部２４，２５，２６の検出結果の内、電流検出部２４の検出結果が最も大きく、電流検出部２５の検出結果が次に大きく、電流検出部２６の検出結果が最も小さいものとする。 In the example of FIG. 2, the current value that flows through the switching element 6b is the largest among the switching elements 6b, 6d, and 6f, the current value that flows through the switching element 6d is the next largest current value, and the current value that flows through the switching element 6f is The smallest shall be assumed. That is, among the detection results of the current detection units 24, 25, and 26, the detection result of the current detection unit 24 is the largest, the detection result of the current detection unit 25 is the next largest, and the detection result of the current detection unit 26 is the smallest. To do.
　駆動回路３９は、電流検出部２４の検出結果と電流検出部２６の検出結果との電流差ΔＩを求める。そして、駆動回路３９は、電流差ΔＩに対応するパルス幅の増減量ｐαを求め、スイッチング素子６ｆに対するＰＷＭ信号のパルス幅を増減量ｐαだけ広げ、スイッチング素子６ｂに対するＰＷＭ信号のパルス幅を増減量ｐαだけ狭くする。なおパルス幅の増減量ｐαには、アーム短絡防止の観点から上限値が設けられ、上アームと下アームのそれぞれのＰＷＭ信号の休止時間幅以下に設定されている。 The drive circuit 39 obtains a current difference ΔI between the detection result of the current detection unit 24 and the detection result of the current detection unit 26. Then, the drive circuit 39 obtains an increase / decrease amount pα of the pulse width corresponding to the current difference ΔI, widens the pulse width of the PWM signal for the switching element 6f by the increase / decrease amount α, and increases / decreases the pulse width of the PWM signal for the switching element 6b. Narrow by pα. The pulse width increase / decrease amount pα has an upper limit value from the viewpoint of preventing arm short-circuiting, and is set to be equal to or less than the pause time width of each of the upper arm and lower arm PWM signals.
　二例目は、電流検出部２４，２５，２６のそれぞれの検出結果、すなわちスイッチング素子６ｂ，６ｄ，６ｆのそれぞれに流れる電流の平均値からの乖離量に応じて、ＰＷＭ信号のパルス幅を調整する方法である。 In the second example, the pulse width of the PWM signal is adjusted according to the detection results of the current detectors 24, 25, and 26, that is, the amount of deviation from the average value of the current flowing through each of the switching elements 6b, 6d, and 6f. It is a method to do.
　駆動回路３９は、電流検出部２４，２５，２６のそれぞれに流れる電流の平均値と、各スイッチング素子の電流差ΔＩとを求める。駆動回路３９は、求めた電流差ΔＩに相当するパルス幅の増減量を求め、一例目と同様の方法で、制御回路９から出力されたＰＷＭ信号を複製して得られるＰＷＭ信号に対して、各スイッチング素子に対するそれぞれのＰＷＭ信号のパルス幅を増減させる。一例目と同様に、このパルス幅の増減量には、アーム短絡防止の観点から上限値が設けられ、上アームと下アームのＰＷＭ信号の休止時間幅以下に設定されている。 The drive circuit 39 obtains the average value of the current flowing through each of the current detection units 24, 25, and 26 and the current difference ΔI of each switching element. The drive circuit 39 obtains the increase / decrease amount of the pulse width corresponding to the obtained current difference ΔI, and with respect to the PWM signal obtained by duplicating the PWM signal output from the control circuit 9 in the same manner as in the first example, The pulse width of each PWM signal for each switching element is increased or decreased. As in the first example, the amount of increase / decrease in the pulse width is set to an upper limit value from the viewpoint of preventing an arm short circuit, and is set to be equal to or less than the pause time width of the PWM signals of the upper arm and the lower arm.
　以上に述べたパルス幅の増減方法は例であり、上記の例以外にも、電流差ΔＩを用いるのではなく、各スイッチング素子に流れる電流値自体を用いて、スイッチング素子に流れる電流値がしきい値以上となった場合、上アームまたは下アームを構成するスイッチング素子の内、しきい値以上の電流が流れたスイッチング素子に対するＰＷＭ信号のパルス幅を一定値分減少させ、当該スイッチング素子以外のスイッチング素子に対するＰＷＭ信号のパルス幅を一定値分増加させる方法を用いてもよい。 The method for increasing / decreasing the pulse width described above is an example. Besides the above example, the current value flowing through each switching element is not used, but the current value flowing through each switching element is used instead of the current difference ΔI. When the threshold value is exceeded, the pulse width of the PWM signal for the switching element in which the current exceeding the threshold flows among the switching elements constituting the upper arm or the lower arm is reduced by a certain value, A method of increasing the pulse width of the PWM signal for the switching element by a certain value may be used.
　制御回路９は、スイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆを一定周期でオン状態とオフ状態に切り替えることで電力変換を行う。また、制御回路９は、前記周期を固定した状態で、スイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆのオンとオフの時間幅を変動させることで電力の調整を行う。一般的にスイッチング素子６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆのオン状態とオフ状態の１サイクルの周期はキャリア周期と呼ばれ、キャリア周期を固定した状態でオンとオフの時間幅を変動させる制御をＰＷＭ制御と呼ぶ。駆動回路３９は、以上に述べたパルス幅の調整を一定時間おきに実施する。この一定時間は、キャリア周期であってもよいし、キャリア周期より長くてもよい。例えば、１分ごとにパルス幅の調整を１０秒間行い、残りの５０秒間はパルス幅の調整をしない、というような制御を実施してもよい。 The control circuit 9 performs power conversion by switching the switching elements 6a, 6b, 6c, 6d, 6e, and 6f between an on state and an off state at a constant period. In addition, the control circuit 9 adjusts the power by changing the ON / OFF time width of the switching elements 6a, 6b, 6c, 6d, 6e, and 6f in a state where the period is fixed. In general, the cycle of one cycle between the ON state and the OFF state of the switching elements 6a, 6b, 6c, 6d, 6e, and 6f is called a carrier cycle, and the ON / OFF time width is changed with the carrier cycle fixed. The control is called PWM control. The drive circuit 39 performs the pulse width adjustment described above at regular intervals. This fixed time may be a carrier cycle or may be longer than the carrier cycle. For example, the control may be performed such that the pulse width is adjusted for 10 seconds every minute and the pulse width is not adjusted for the remaining 50 seconds.
　また、処理を単純化するために、電流差ΔＩがしきい値未満の場合には調整を行わず、電流差ΔＩがしきい値を超えたときに、最も電流値が大きいスイッチング素子のパルス幅を固定値分狭め、最も電流値が小さいスイッチング素子のパルス幅を固定値分広げるという調整を行ってもよい。 In order to simplify the processing, no adjustment is made when the current difference ΔI is less than the threshold value, and the pulse width of the switching element having the largest current value when the current difference ΔI exceeds the threshold value. May be adjusted such that the pulse width of the switching element having the smallest current value is widened by a fixed value.
　なお、図１の例では、インバータモジュール６の外部に設けられた駆動回路３９がパルス幅の調整、すなわちパルス幅の増減を行うようにしたが、インバータモジュール６の内部でパルス幅の調整を行ってもよい。この場合、インバータモジュール６へ電流検出部２４，２５，２６の検出結果を示す信号を入力する。この場合、電流検出部２４，２５，２６の検出結果自体をインバータモジュール６へ入力する替わりに、電流検出部２４，２５，２６の検出結果に基づいて、スイッチング素子６ｂ，６ｄ，６ｆの内、最も電流値の大きいスイッチング素子を示す信号を外部へ出力し、または最も電流値の大きいスイッチング素子の電流値の電流差Δとを示す信号を外部へ出力してもよい。 In the example of FIG. 1, the drive circuit 39 provided outside the inverter module 6 adjusts the pulse width, that is, increases or decreases the pulse width. However, the pulse width is adjusted inside the inverter module 6. May be. In this case, signals indicating detection results of the current detection units 24, 25, and 26 are input to the inverter module 6. In this case, instead of inputting the detection results of the current detection units 24, 25, and 26 to the inverter module 6, based on the detection results of the current detection units 24, 25, and 26, of the switching elements 6b, 6d, and 6f, A signal indicating the switching element having the largest current value may be output to the outside, or a signal indicating the current difference Δ between the current values of the switching elements having the largest current value may be output to the outside.
　また、図１の例では、ＰＷＭ信号がオンからオフに切り替わるタイミングでＰＷＭ信号のパルス幅の増減を行うようにしたが、ＰＷＭ信号がオフからオンに切り替わるタイミングで実施しても同様の効果が得られる。 In the example of FIG. 1, the pulse width of the PWM signal is increased / decreased at the timing when the PWM signal is switched from on to off. However, the same effect can be achieved even when the PWM signal is switched from off to on. can get.
　上アームを構成するスイッチング素子６ａ，６ｃ，６ｅのそれぞれに対するＰＷＭ信号のパルス幅の調整方法は、下アームを構成するスイッチング素子６ｂ，６ｄ，６ｆのそれぞれに対するＰＷＭ信号のパルス幅の調整方法と同様である。また、インバータモジュール５およびインバータモジュール７のパルス幅の調整方法は、インバータモジュール６のパルス幅の調整方法と同様である。 The method for adjusting the pulse width of the PWM signal for each of the switching elements 6a, 6c, 6e constituting the upper arm is the same as the method for adjusting the pulse width of the PWM signal for each of the switching elements 6b, 6d, 6f constituting the lower arm. It is. The method for adjusting the pulse width of the inverter module 5 and the inverter module 7 is the same as the method for adjusting the pulse width of the inverter module 6.
　また本実施の形態に係る電力変換装置１００は、電流検出部２１から３８がインバータモジュールを構成する複数のスイッチング素子のそれぞれに対応付けて設けられ、複数のスイッチング素子のそれぞれに流れる電流を検出するように構成される。この構成により、スイッチング素子に過電流が流れた場合の保護として、電流検出部２１から３８により検出された電流の内、少なくとも１つの電流が許容値を超えた場合、駆動回路３９が全てのスイッチング素子にオフ信号を出力して、電力変換装置１００の動作を停止するようにしてもよい。これにより応答速度の速い電流検出結果に基づいて電力変換装置１００の動作を停止させることができるため、異常発生時に速やかに電力変換装置１００を停止でき、スイッチング素子の破壊を防止できる。またこれに伴う電力変換装置１００の発煙および発火を防止できる。 Further, in power conversion device 100 according to the present embodiment, current detection units 21 to 38 are provided in association with each of a plurality of switching elements constituting the inverter module, and detect currents flowing through each of the plurality of switching elements. Configured as follows. With this configuration, as a protection when an overcurrent flows through the switching element, when at least one of the currents detected by the current detection units 21 to 38 exceeds an allowable value, the drive circuit 39 performs all switching. The operation of the power conversion device 100 may be stopped by outputting an off signal to the element. As a result, the operation of the power conversion device 100 can be stopped based on the current detection result with a fast response speed. Therefore, the power conversion device 100 can be stopped quickly when an abnormality occurs, and the switching element can be prevented from being destroyed. Further, smoke and ignition of the power conversion device 100 can be prevented.
　比較として、電流検出部２１から３８を使用せず、インバータ５１の出力電流を電流検出部１７で検出し、その電流が過電流であることを検出して保護停止させる場合、電流検出部１７の電流検知結果が一旦制御回路９に送信され、制御回路９で過電流を判定した後に、駆動回路３９へオフ信号を送信する動作が必要となる。そのため保護停止までに数１００ｕ秒を要する。 As a comparison, when the current detection unit 17 detects the output current of the inverter 51 without using the current detection units 21 to 38 and detects that the current is an overcurrent and stops the protection, the current detection unit 17 After the current detection result is once transmitted to the control circuit 9 and the control circuit 9 determines an overcurrent, an operation of transmitting an off signal to the drive circuit 39 is required. Therefore, it takes several hundreds of seconds to stop the protection.
　これに対して、実施の形態１のように電流検出部２１から３８で過電流を検出し、過電流の結果を制御回路９を介さずに直接駆動回路３９に送信され、駆動回路３９がスイッチング素子を直接停止させた場合、保護停止までに要する時間は数ｕ秒で済む。 On the other hand, as in the first embodiment, the overcurrent is detected by the current detectors 21 to 38, and the result of the overcurrent is transmitted directly to the drive circuit 39 without passing through the control circuit 9, and the drive circuit 39 is switched. When the element is stopped directly, the time required to stop the protection is only a few u seconds.
　以上より、電流検出部２１から３８を用いて過電流の保護動作を行う場合、応答速度の速い電流検出に基づいて動作を停止させることができるため、異常時に速やかに停止でき、素子の破壊を防止できる。 As described above, when the overcurrent protection operation is performed using the current detection units 21 to 38, the operation can be stopped based on the current detection with a fast response speed, so that the operation can be quickly stopped at the time of abnormality, and the element is destroyed. Can be prevented.
　また本実施の形態に係る電力変換装置１００の駆動回路３９は、パルス幅の調整を一定時間おきに実施する。これにより、経時的な温度変化に起因する電流のアンバランス分、または経年変化による特性変化に起因する電流のアンバランス分を補正できる。 In addition, the drive circuit 39 of the power conversion apparatus 100 according to the present embodiment adjusts the pulse width at regular intervals. As a result, it is possible to correct the current unbalance due to the temperature change over time or the current unbalance due to the characteristic change due to the secular change.
　以上のように、本実施の形態に係る電力変換装置は、２つのスイッチング素子が直列に接続されたスイッチング素子対を、複数並列に接続されたインバータモジュールを相ごとに備える。このため、コストを抑えて大電流化を実現できる。また本実施の形態に係る電力変換装置は、スイッチング素子に流れる電流を検出して各スイッチング素子の特性差異を推定し、駆動信号であるＰＷＭ信号のパルス幅を調整することにより、電流のアンバランスを抑制するように構成される。これにより、インバータモジュールとしての電流容量を決定する際、電流のアンバランスの分を考慮しなくてよく、各スイッチング素子の電流容量を有効に活用できる。 As described above, the power conversion device according to the present embodiment includes a switching element pair in which two switching elements are connected in series, and a plurality of inverter modules connected in parallel for each phase. For this reason, it is possible to realize a large current at a reduced cost. In addition, the power conversion device according to the present embodiment detects the current flowing through the switching element, estimates the characteristic difference between the switching elements, and adjusts the pulse width of the PWM signal that is the drive signal, thereby imbalances the current. Configured to suppress. Thereby, when determining the current capacity as the inverter module, it is not necessary to consider the current unbalance, and the current capacity of each switching element can be used effectively.
　なお、図１の例では、１つのインバータモジュールが３対のスイッチング素子で構成される例を示したが、図１の例に限定されず、２対以上のスイッチング素子で１つのインバータモジュールを構成してもよい。 In the example of FIG. 1, an example in which one inverter module is configured by three pairs of switching elements is shown. However, the example is not limited to the example of FIG. 1, and one inverter module is configured by two or more pairs of switching elements. May be.
実施の形態２．
　次に実施の形態２に係る電力変換装置を説明する。実施の形態１では、スイッチング素子ごとに電流を検出する電流検出部を備える例を説明したが、実施の形態２では、各インバータモジュールのアームごとに電流検出部を備える例について説明する。 Embodiment 2. FIG.
Next, a power converter according to Embodiment 2 will be described. In the first embodiment, an example in which a current detection unit that detects a current is provided for each switching element has been described. In the second embodiment, an example in which a current detection unit is provided for each arm of each inverter module will be described.
　図３は実施の形態２に係る電力変換装置の構成図である。図３には、実施の形態２に係る電力変換装置１００－２を構成する機能の内、一部の機能のみが例示される。実施の形態１との相違点は、実施の形態２に係る電力変換装置１００－２は、実施の形態１の電流検出部２４，２５，２６の代わりに電流検出部４０を備え、実施の形態１の電流検出部３３，３４，３５の代わりに電流検出部４１を備え、駆動回路３９の代わりに駆動回路３９ａを備えることである。その他の構成要素は実施の形態１と同様である。 FIG. 3 is a configuration diagram of the power conversion device according to the second embodiment. FIG. 3 illustrates only a part of functions constituting the power conversion device 100-2 according to the second embodiment. The difference from the first embodiment is that a power conversion device 100-2 according to the second embodiment includes a current detection unit 40 instead of the current detection units 24, 25, and 26 of the first embodiment. 1 is provided with a current detection unit 41 instead of the current detection units 33, 34, and 35, and a drive circuit 39 a is provided instead of the drive circuit 39. Other components are the same as those in the first embodiment.
　電流検出部４０は、インバータモジュール６の下アームのスイッチング素子６ｂ，６ｄ，６ｆの接続線の合流点で電流を検出する。同様に、電流検出部４１は、インバータモジュール６の上アームのスイッチング素子６ａ，６ｃ，６ｅの接続線の合流点で電流を検出する。なおインバータモジュール５は、インバータモジュール６と同様に、下アームのスイッチング素子５ｂ，５ｄ，５ｆの接続線の合流点で電流を検出する電流検出部と、上アームのスイッチング素子５ａ，５ｃ，５ｅの接続線の合流点で電流を検出する電流検出部とを備える。またインバータモジュール７は、インバータモジュール６と同様に、下アームのスイッチング素子７ｂ，７ｄ，７ｆの接続線の合流点で電流を検出する電流検出部と、上アームのスイッチング素子７ａ，７ｃ，７ｅの接続線の合流点で電流を検出する電流検出部とを備える。 The current detection unit 40 detects a current at the junction of the connection lines of the switching elements 6b, 6d, and 6f on the lower arm of the inverter module 6. Similarly, the current detection unit 41 detects a current at the junction of the connection lines of the switching elements 6a, 6c, and 6e of the upper arm of the inverter module 6. As in the inverter module 6, the inverter module 5 includes a current detection unit that detects current at the junction of the connecting lines of the lower arm switching elements 5b, 5d, and 5f, and the upper arm switching elements 5a, 5c, and 5e. A current detection unit that detects current at a junction of the connection lines. Similarly to the inverter module 6, the inverter module 7 includes a current detection unit that detects current at the junction of the connecting lines of the lower arm switching elements 7b, 7d, and 7f, and the upper arm switching elements 7a, 7c, and 7e. A current detection unit that detects current at a junction of the connection lines.
　図３に示した電流検出部４０は、スイッチング素子６ｂ，６ｄ，６ｆの全てが電流の流れる状態、すなわちオンとなっている場合、スイッチング素子６ｂ，６ｄ，６ｆに流れる電流の和を検出できる。一方、スイッチング素子６ｂ，６ｄ，６ｆの全てが電流の流れる状態では、電流検出部４０は、スイッチング素子６ｂ，６ｄ，６ｆの各々に流れる電流を個別に検出することはできない。 3 can detect the sum of currents flowing through the switching elements 6b, 6d, and 6f when all of the switching elements 6b, 6d, and 6f are in a state where current flows, that is, when the switching elements 6b, 6d, and 6f are turned on. On the other hand, in the state where all of the switching elements 6b, 6d, and 6f flow, the current detection unit 40 cannot individually detect the current that flows through each of the switching elements 6b, 6d, and 6f.
　このため、本実施の形態では、電力変換装置１００－２を通常運転させていない期間で、スイッチング素子６ｂ，６ｄ，６ｆの開閉の組み合わせを変更して電流を流すことにより、スイッチング素子６ｂ，６ｄ，６ｆの素子特性、すなわちオン抵抗のばらつきを求める。具体的には、駆動回路３９ａは、スイッチング素子６ｂをオンとしかつスイッチング素子６ｄ，６ｆをオフとするよう制御する。この状態で、駆動回路３９ａは、電流検出部４０により検出された電流値、すなわちスイッチング素子６ｂに流れる電流値を取得して記憶する。また、駆動回路３９ａは、同様に、スイッチング素子６ｄをオンとしかつスイッチング素子６ｂ，６ｆをオフとして、スイッチング素子６ｄに流れる電流値を取得して保持し、スイッチング素子６ｆをオンとしかつスイッチング素子６ｂ，６ｄをオフとして、スイッチング素子６ｆに流れる電流を取得して保持する。駆動回路３９ａは、これらの電流の検出により、スイッチング素子６ｂ，６ｄ，６ｆのオン抵抗の比率、すなわちスイッチング素子６ｂ，６ｄ，６ｆの特性のばらつきを求めることができる。駆動回路３９ａは、スイッチング素子６ｂ，６ｄ，６ｆのオン抵抗の比率Ｒ６ｂ，Ｒ６ｄ，Ｒ６ｆを算出して保持する。 For this reason, in the present embodiment, the switching elements 6b, 6d are made to flow by changing the combination of opening and closing of the switching elements 6b, 6d, 6f while the power converter 100-2 is not normally operated. , 6f, that is, variation in on-resistance. Specifically, the drive circuit 39a controls to turn on the switching element 6b and turn off the switching elements 6d and 6f. In this state, the drive circuit 39a acquires and stores the current value detected by the current detection unit 40, that is, the current value flowing through the switching element 6b. Similarly, the drive circuit 39a turns on the switching element 6d and turns off the switching elements 6b and 6f, acquires and holds the current value flowing through the switching element 6d, turns on the switching element 6f, and turns on the switching element 6b. , 6d are turned off, and the current flowing through the switching element 6f is acquired and held. By detecting these currents, the drive circuit 39a can determine the ratio of the on resistances of the switching elements 6b, 6d, and 6f, that is, the variation in the characteristics of the switching elements 6b, 6d, and 6f. The drive circuit 39a calculates and holds the on-resistance ratios R6b, R6d, and R6f of the switching elements 6b, 6d, and 6f.
　同様に、駆動回路３９ａは、上アームのスイッチング素子６ａ，６ｃ，６ｅについても、スイッチング素子６ａ，６ｃ，６ｅの開閉の組み合わせを変更して電流を流すことにより、スイッチング素子６ａ，６ｃ，６ｅのオン抵抗の比率Ｒ６ａ，Ｒ６ｃ，Ｒ６ｅを算出して保持する。インバータモジュール５，７についても、同様に、アームごとにスイッチング素子のオン抵抗の比率を求めることができる。 Similarly, the drive circuit 39a also changes the combination of opening and closing of the switching elements 6a, 6c, and 6e for the switching elements 6a, 6c, and 6e of the upper arm, and allows the current to flow to change the switching elements 6a, 6c, and 6e. The on-resistance ratios R6a, R6c, and R6e are calculated and held. Similarly, for the inverter modules 5 and 7, the ratio of the on-resistance of the switching element can be obtained for each arm.
　そして、電力変換装置を通常運転させる期間では、インバータモジュール６の駆動回路３９ａは、上アームの電流検出部により検出された電流と、保持しているオン抵抗の比率Ｒ６ａ，Ｒ６ｃ，Ｒ６ｅとに基づいて、スイッチング素子６ａ，６ｃ，６ｅの各々に流れる電流、すなわち分流を算出する。そして、駆動回路３９ａは、制御回路９から出力される上アーム用のＰＷＭ信号Ｕｐを３つに複製し、算出したスイッチング素子６ａ，６ｃ，６ｅに流れる電流に基づいて、３つの信号のパルス幅を調整し、パルス幅調整後のＰＷＭ信号を、対応するスイッチング素子へ出力する。スイッチング素子６ａ，６ｃ，６ｅの各々に流れる電流に基づくパルス幅の調整方法は、実施の形態１と同様である。 In the period in which the power converter is normally operated, the drive circuit 39a of the inverter module 6 is based on the current detected by the current detection unit of the upper arm and the on-resistance ratios R6a, R6c, and R6e that are held. Thus, the current flowing through each of the switching elements 6a, 6c, 6e, that is, the shunt current is calculated. Then, the drive circuit 39a duplicates the upper arm PWM signal Up output from the control circuit 9 into three, and based on the calculated currents flowing through the switching elements 6a, 6c, and 6e, the pulse widths of the three signals. The PWM signal after adjusting the pulse width is output to the corresponding switching element. The method for adjusting the pulse width based on the current flowing through each of the switching elements 6a, 6c, 6e is the same as in the first embodiment.
　インバータモジュール６の駆動回路３９ａは、同様に、下アームの電流検出部４０により検出された電流と、保持しているオン抵抗の比率Ｒ６ｂ，Ｒ６ｄ，Ｒ６ｆとに基づいて、スイッチング素子６ｂ，６ｄ，６ｆの各々に流れる電流、すなわち分流を算出する。そして、インバータモジュール６の駆動回路３９ａは、制御回路９から出力される下アーム用のＰＷＭ信号Ｕｎを３つに複製し、算出したスイッチング素子６ｂ，６ｄ，６ｆに流れる電流に基づいて、３つの信号のパルス幅を調整し、パルス幅調整後のＰＷＭ信号を、対応するスイッチング素子へ出力する。スイッチング素子６ｂ，６ｄ，６ｆの各々に流れる電流に基づくパルス幅の調整方法は、実施の形態１と同様である。 Similarly, the drive circuit 39a of the inverter module 6 includes switching elements 6b, 6d, and 6d based on the current detected by the current detection unit 40 of the lower arm and the on-resistance ratios R6b, R6d, and R6f that are held. The current flowing through each of 6f, that is, the shunt current is calculated. Then, the drive circuit 39a of the inverter module 6 duplicates the lower arm PWM signal Un output from the control circuit 9 into three, and based on the calculated currents flowing through the switching elements 6b, 6d, and 6f, The pulse width of the signal is adjusted, and the PWM signal after the pulse width adjustment is output to the corresponding switching element. The method for adjusting the pulse width based on the current flowing through each of the switching elements 6b, 6d, 6f is the same as in the first embodiment.
　インバータモジュール５，７は、インバータモジュール６と同様に、アームごとに、制御回路９から入力されるＰＷＭ信号の複製、および電流に応じたパルス幅の調整を実施する。 The inverter modules 5 and 7 perform the duplication of the PWM signal input from the control circuit 9 and the adjustment of the pulse width according to the current for each arm, similarly to the inverter module 6.
　なお、上記の例では、電力変換装置を通常運転させていない期間で、スイッチング素子の開閉の組み合わせを変更して電流を流すことにより、オン抵抗の比率を算出したが、これに限らず、予めオン抵抗の比率を測定しておき、オン抵抗の比率をテーブルとして保持してもよい。 In the above example, the ratio of the on-resistance is calculated by changing the combination of opening and closing of the switching elements and flowing the current in a period in which the power conversion device is not normally operated. The on-resistance ratio may be measured in advance, and the on-resistance ratio may be held as a table.
　また、インバータモジュール内またはインバータモジュール外で各スイッチング素子の温度と等価な温度を検出し、スイッチング素子ごとのオン抵抗の比率を温度の検出結果に基づいて求めてもよい。 Also, the temperature equivalent to the temperature of each switching element may be detected inside or outside the inverter module, and the ratio of the on-resistance for each switching element may be obtained based on the temperature detection result.
　また、上記の例では、上アームと下アームの両方を、アームごとに電流検出部を備えるようにしたが、上アームはアームごとに電流検出部を備え、下アームは実施の形態１で述べたようにスイッチング素子ごとに電流検出部を備える、または、下アームはアームごとに電流検出部を備え、上アームは実施の形態１で述べたようにスイッチング素子ごとに電流検出部を備えるというように、実施の形態１と本実施の形態を組み合わせてもよい。 In the above example, both the upper arm and the lower arm are provided with a current detection unit for each arm. However, the upper arm is provided with a current detection unit for each arm, and the lower arm is described in the first embodiment. As described in the first embodiment, the current detection unit is provided for each switching element, or the lower arm includes the current detection unit for each arm, and the upper arm includes the current detection unit for each switching element as described in the first embodiment. In addition, the first embodiment and this embodiment may be combined.
　また、本実施の形態ではオン抵抗比率を算出する例を挙げたが、その他電流のアンバランスを生じる要因となるスイッチングタイミングの差異に応じてパルスを調整してもよい。例えば素子のしきい値電圧がばらついている場合、スイッチングタイミングに差異が生じるため、ターンオン時にはしきい値電圧が低く先にオンする素子に、またターンオフ時にはしきい値電圧が高く最後にオフする素子に電流が集中する。駆動信号の立ち上りから一定時間経過後の電流値を検出することによってスイッチングタイミングの差異を判断でき、これを基にパルスを調整することでオン抵抗比率を算出する例と同様の効果を得ることができる。 In the present embodiment, an example of calculating the on-resistance ratio has been described. However, the pulse may be adjusted according to a difference in switching timing that causes other current imbalance. For example, when the threshold voltage of the element varies, a difference occurs in the switching timing. Therefore, the element whose threshold voltage is low first when turning on is turned on first, and the element whose threshold voltage is high when turning off is finally turned off. Current concentrates on. The difference in switching timing can be determined by detecting the current value after a lapse of a certain time from the rise of the drive signal, and the same effect as the example of calculating the on-resistance ratio by adjusting the pulse based on this can be obtained. it can.
　以上のように本実施の形態に係る電力変換装置１００は、電流検出部４０および電流検出部４１がインバータモジュールを構成する上アームおよび下アームに対応付けて設けられ、上アームおよび下アームに流れる電流を検出するように構成される。この構成により、アームごとに検出した電流と、同一アーム内のスイッチング素子間のオン抵抗の比率とに基づいて、スイッチング素子に出力するＰＷＭ信号のパルス幅を調整するようにした。このため、実施の形態１と同様に電流のアンバランスを抑制でき、実施の形態１に比べ電流検出部の数を低減させることができ、低コストと小型化を実現できる。 As described above, in power conversion device 100 according to the present embodiment, current detection unit 40 and current detection unit 41 are provided in association with the upper arm and the lower arm constituting the inverter module, and flow to the upper arm and the lower arm. It is configured to detect current. With this configuration, the pulse width of the PWM signal output to the switching element is adjusted based on the current detected for each arm and the ratio of the on-resistance between the switching elements in the same arm. Therefore, current imbalance can be suppressed as in the first embodiment, the number of current detection units can be reduced as compared with the first embodiment, and cost and size can be reduced.
　以上の実施の形態に示した構成は、本発明の内容の一例を示すものであり、別の公知の技術と組み合わせることも可能であるし、本発明の要旨を逸脱しない範囲で、構成の一部を省略、変更することも可能である。 The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.
　１　直流電源、２，４，１０　コンデンサ、３，１１，１２　リアクトル、５，６，７　インバータモジュール、５ａ，５ｂ，５ｃ，５ｄ，５ｅ，５ｆ，６ａ，６ｂ，６ｃ，６ｄ，６ｅ，６ｆ，７ａ，７ｂ，７ｃ，７ｄ，７ｅ，７ｆ　スイッチング素子、８　商用電源系統、９　制御回路、１３，１４　リレー、１５，１６　電圧検出部、１７，２１，２２，２３，２４，２５，２６，２７，２８，２９，３０，３１，３２，３３，３４，３５，３６，３７，３８，４０，４１　電流検出部、１８　制御部、１９ａ　正極側直流母線、１９ｂ　負極側直流母線、３９，３９ａ　駆動回路、５０　コンバータ、５１　インバータ、１００，１００－２　電力変換装置。 1 DC power supply, 2, 4, 10 capacitor, 3, 11, 12 reactor, 5, 6, 7 inverter module, 5a, 5b, 5c, 5d, 5e, 5f, 6a, 6b, 6c, 6d, 6e, 6f, 7a, 7b, 7c, 7d, 7e, 7f switching element, 8 commercial power supply system, 9 control circuit, 13, 14 relay, 15, 16 voltage detector, 17, 21, 22, 23, 24, 25, 26, 27 , 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 40, 41 Current detection unit, 18 control unit, 19a positive side DC bus, 19b negative side DC bus, 39, 39a drive Circuit, 50 converter, 51 inverter, 100, 100-2 power converter.

Claims (6)

  1. 　２つのスイッチング素子が直列に接続されたスイッチング素子対が複数並列に接続されたインバータモジュールと、
    　前記スイッチング素子を制御するパルス幅変調信号を生成する制御部と、
    　前記スイッチング素子に流れる電流を検出する電流検出部と
    　を備え、
    　前記制御部は、前記電流検出部が検出した電流を用いて、前記複数のスイッチング素子対の各々を駆動するためのパルス幅変調信号のパルス幅を調整するパルス幅調整部を備えることを特徴とする電力変換装置。     An inverter module in which a plurality of switching element pairs in which two switching elements are connected in series are connected in parallel;
    A control unit for generating a pulse width modulation signal for controlling the switching element;
    A current detection unit for detecting a current flowing through the switching element,
    The control unit includes a pulse width adjustment unit that adjusts a pulse width of a pulse width modulation signal for driving each of the plurality of switching element pairs using the current detected by the current detection unit. Power converter.
  2. 　前記電流検出部は、前記インバータモジュールを構成する複数のスイッチング素子のそれぞれに対応付けて設けられ、前記インバータモジュールを構成する複数のスイッチング素子のそれぞれに流れる電流を検出することを特徴とする請求項１に記載の電力変換装置。 The current detection unit is provided in association with each of a plurality of switching elements constituting the inverter module, and detects a current flowing through each of the plurality of switching elements constituting the inverter module. The power converter according to 1.
  3. 　前記電流検出部は、前記インバータモジュールを構成する上アームおよび下アームに対応付けて設けられ、前記上アームおよび前記下アームに流れる電流を検出することを特徴とする請求項１に記載の電力変換装置。 2. The power conversion according to claim 1, wherein the current detection unit is provided in association with an upper arm and a lower arm constituting the inverter module, and detects a current flowing through the upper arm and the lower arm. apparatus.
  4. 　パルス幅調整部は、前記パルス幅の調整を一定時間おきに実施することを特徴とする請求項１から請求項３の何れか一項に記載の電力変換装置。 The power converter according to any one of claims 1 to 3, wherein the pulse width adjustment unit performs the adjustment of the pulse width at regular intervals.
  5. 　前記スイッチング素子は、ワイドバンドギャップ半導体によって形成されていることを特徴とする請求項１から請求項４の何れか一項に記載の電力変換装置。 The power conversion device according to any one of claims 1 to 4, wherein the switching element is formed of a wide band gap semiconductor.
  6. 　前記ワイドバンドギャップ半導体は、炭化珪素であることを特徴とする請求項５に記載の電力変換装置。
          The power converter according to claim 5, wherein the wide band gap semiconductor is silicon carbide.
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JP2014138538A (en) * 2013-01-18 2014-07-28 Fuji Electric Co Ltd Power conversion device

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JP2014138538A (en) * 2013-01-18 2014-07-28 Fuji Electric Co Ltd Power conversion device

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CN113597738A (en) * 2019-03-28 2021-11-02 三菱电机株式会社 Motor driving device, electric vacuum cleaner and hand dryer
US11831249B2 (en) 2019-11-06 2023-11-28 Toshiba Mitsubishi-Electric Industrial Systems Corporation Power conversion apparatus

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